Systems of simultaneous operation of low- and high ... · Systems of simultaneous operation of low-...

International Geothermal Conference, Reykjavík, Sept. 2003 Session #3

Systems of simultaneous operation of low- and high-temperature heating installations and the effect on

the degree of geothermal energy utilization in a geothermal heating plant

Władysław Nowak, Aleksander A. Stachel Department of Heat Engineering, Technical University of Szczecin,

al. Piastów 19, PL 70-310 Szczecin, Poland E-mail: [email protected]

Abstract

One of the conditions for rationalisation of geothermal water use is to improve the geothermal system load factor. In order to fulfill this condition it is advised to target predominantly low-temperature heat customers, or a combination of customers having high temperature installations with customers having low-temperature installations. This enables more effective cooling of municipal heating water and increasing the geothermal system load factor. The authors carried out analyses to determine the influence the combining of high-temperature and low-temperature installations had on improving the utilisation of geothermal energy in a geothermal heating plant. The main purpose of this work was to evaluate the level of influence the application of low-temperature heating systems has on the degree of the geothermal energy in the geothermal heating plant, which supplements the heat distribution network supplying two groups of heat customers having the distinct shares in a heat consumption. These studies are very interesting as concerns the possibility of modernising the existing heating systems by the application of the geothermal unit in a conventional heating plant.

Keywords: geothermal energy, geothermal heating plant, geothermal energy utilisation.

1 Geothermal energy potential in Poland Poland belongs to the group of countries having a large potential of low or medium enthalpy geothermal waters (Wisniewski, 1997). The temperature and the degree of geothermal water mineralisation usually depend on the depth of rock deposits creating the underground water reservoir heated with energy from the Earth's centre. Sokolowski, Gorecki and Ney (Ney and Sokolowski, 1987; Gorecki, 1996; Sokolowski, 1997) prepared an evaluation of the Polish energy potential that presented the geological conditions and defined the areas for geothermal water deposits. According to Sokolowski, the Polish geothermal water resources comprise ca. 6500 km3. This geothermal water resource has the temperature range of 25-120°C, which makes it useful for direct utilisation for heating, hot tap water production as well as technological and medical purposes. The potential is rather equally distributed within the major part of the Polish territory, in separate geothermal basins and subbasins, in defined geothermal provinces and regions. According to the existing evaluations, some 60% of this potential may be used in practice. The most favourable conditions are in Polish Lowlands (Niż Polski), which makes the region a potential geothermal basin. Favourable conditions are also found in Podhale and Sudety (Southern Poland).

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1.1 General rules for geothermal water management Heat demand differs with time. It relies mostly on space heating demand, which varies with outdoor temperature. The ordered chart is the basis for defining the amount of useful heat (Kabat et al., 1999; Nowak et al., 2000; Nowak and Stachel, 1999, 2000b, 2001). While preparing the ordered heat demand chart, it is necessary to take into consideration technological heat consumption for industrial plants, agriculture, handicraft and other customers. The chart is very helpful for deciding the concepts and design of the heat sources structure, especially when choosing systems for energy supply from geothermal water. The systems depend on the geothermal water parameters used for the process and customers demand resulting from an ordered curve. Three sets are possible in this case (Nowak et al., 2000; Sobanski et al., 2000): • Monovalent set where all the heat is taken from a geothermal installation. The

installed capacity is set according to the heat demand, defined for the calculated outdoor temperature. Low value of the annual co-efficient of the power leads to heat cost increase. The set may be used at high geothermal water temperature (ca. 110°C) and/or at cascade utilisation of water enthalpy in various heating- and technological devices.

• Bivalent set where conventional boilers support the geothermal source. In this set, it is possible to use its capacity more completely throughout the whole heating period. A boiler supports the system only during the peak load period. Outside the heating period, the geothermal source supplies energy only for hot tap or technological water production, depending on the demand. The set makes it possible to reach high values for geothermal intake utilisation and it is therefore often used. Existing boilers may be used as peak load heat sources. If it is necessary to build a new peak load energy source, investment costs increase.

• Combined set where a part of customers are supplied by a geothermal installation (low temperature heating) and the remaining part by a conventional boiler (traditional heating). By combining the two systems, it is possible to increase the utilisation value for the geothermal installation, which out of the heating season, is used for hot tap or technological water production for all the customers. Utilisation of nearly full capacity of the geothermal installation may be reached in this case and it causes a decrease of heat production costs.

The generally presented schemes constitute the basic methods for geothermal energy management. Detailed solutions and their technical and operational effects are directly dependent on local geothermal solutions and possibilities of utilisation of periodical surplus geothermal energy heat, occurring mostly out of the heating season (Kabat, 2001).

1.2 Concept of geothermal energy utilisation Geothermal waters constituting a potential heat source for the economy present within the Polish territory are usually of 100°C temperature. Therefore, it differs from temperatures traditionally used in district heating networks (150/70°C), which are used by fossil fuelled systems. Maximum temperature of heating water used in heating installations in buildings is 95/70°C. Conventional heat sources supply centralised district heating systems with energy carriers (steam, circulation water) of temperature usually exceeding the temperature of heat required by heat or technological heat customers. On the other hand, geothermal water often has the temperature close or even lower than the temperature required for most district heating installations. This limits the direct

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utilisation of geothermal waters energy to low temperature heat customers or requires the use of various devices supporting the geothermal energy source. Such constraint results from the kind of heating systems used in Poland, where the supply heating water temperature is 95/70°C, which corresponds to the minimum external calculation temperature of –16°C. Utilisation of geothermal energy for heating purposes in municipal systems, agriculture, technical processes as support for conventional heating and power plants and as the basic energy carrier in low temperature power plants is the most effective and simplest way of geothermal energy management. When the temperature of a geothermal energy carrier is insufficient for water heating in a heating installation, heat pumps or peak load boilers are introduced into the installation, or the installation has to be improved and changed. Their task is to increase the temperature of the heated water to the required value. The variety of possible technical solutions and structures of the source devices for heat production from the Earth's centre energy results from the need of adjusting the kind and size of the geothermal intake for the needs and parameters of the heat customer installation taking into consideration local parameters of water and the results of economic analysis (Ney and Sokolowski, 1987; Nowak et al., 2000; Nowak and Stachel, 1999, 2000). The scheme of an example of a geothermal heating plant is presented in Figure 1.

e of a geothermal heating plant with a heat exchanger and a peak

The concept of producing geothermal energy presented in the figure is based on a

low heat exchanger where geothermal water heat is passed to the n

• hen the heat supplied by the geothermal heat e

„by-pass”

Peak-demand boiler

wm∆ &wm& 2TT gww −=

2TT gzp −=

spT

szT,m&

Heatexchanger

wm& m&

ggz V,T &ggw V,T &

km&Consumers

of heat

Figure 1: Schemboiler.

two-hole system, in combintion with a conventional heating plant, consisting among others things of:

• counterfetwork circulation water, a peak load boiler, used wxchanger does not satisfy the demand and if the temperature of the

circulation water behind the Tw heat exchanger is lower than the required temperature for the network water at Tsz supply.

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Heat for heating purposes and for hot tap water production is produced in a central heat source and distributed to customers by a transmission network, consisting of a circulation network of water at the temperature of 95/70°C.

1.3 Evaluation of possibilities of geothermal energy production The amount of geothermal energy possible for production in a heat exchanger is dependent upon the geothermal deposit- and characteristics of district heating networks. The characteristics of the resource may be presented in the form of property charts, presenting possibilities of geothermal energy production. The chart presenting the useful energy content of geothermal water taken from the ground, which depends upon the quantity of geothermal water taken from the ground, its temperature and the level of cooling achieved in the heat exchanger (Figure 2). The temperature of the geothermal water taken from the ground determines its quality and is a quantity significant from the point of view of its possibilities for utilisation (Kabat et al., 1999; Nowak and Stachel, 1999, 2001). Intake system operation time is an important factor deciding on the effectiveness of geothermal energy utilisation and limiting the amount of produced geothermal energy. The maximum heat quantity may be achieved in case of the system operating all year (Kabat et al., 1999; Nowak et al., 2000; Sobanski et al., 2000).

Tsp=25°C

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

25 35 45 55 65 75 85

Temperature of geothermal water Tg [°C]

Geo

ther

mal

ene

rgy

[GJ/

a] Vg= 50m3/h

Vg= 75m3/h

Vg=100m3/h

Vg=125m3/h

Vg=150m3/h

Figure 2: Possibilities of producing geothermal energy from a geothermal deposit.

The quantities presented in Figure 2 only define possibilities of geothermal energy production and are equal to its utilisation in a geothermal heat exchanger. This results mostly from possibilities of its utilisation in heat customers and depends upon their characteristics, which constitute of the thermal demand and temperatures of the energy carrier on the inflow and outflow. On this basis, real possibilities of geothermal energy production for heating purposes in a heat exchanger may be determined (Nowak and Stachel, 1999, 2000a, 2001a; Kabat et al., 1999). Securing the proper temperature of the energy carrier for heat customers is an important factor for a geothermal heating plant operation. This topic was discussed in many papers (Kabat et al., 1999; Nowak et al., 2000; Nowak and Stachel, 2000b; Sobanski et al., 2000). When the temperature on customer-end-user inlet is supposed

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to be higher than geothermal water, further water may be heated in a correctly chosen peak load boiler. In a schema presented in Figure 2 one may clearly see that temperature of the network circulation water (supplying and return water) has a significant influence on the level of geothermal energy utilisation for a certain temperature of geothermal water taken from the ground and for a given quantity of geothermal water. The return water temperature should be as low as possible. Therefore, under real conditions, one should analyse the possibilities of heat utilisation for heating, hot tap water production and technological purposes taking into consideration possibilities of reducing the pumped geothermal water by decreasing the temperature return water of the district-heating network. The small temperature difference between district heating water and geothermal water gives a narrow degree of geothermal energy utilisation. If the geothermal water temperature is high enough, parameters of the return district heating water have no influence on the amount of the transferred heat.

2 Possibilities of increasing utilization of geothermal heat As was shown, the temperature of the pumped geothermal water, limited by the return district heating water, has significant influence on the maximal utilisation of geothermal energy. The district heating return water temperature should be as low as possible. In extreme conditions, conventional heating systems work at water temperatures 95/70°C. High return district heating water temperature significantly limits or eliminates the possibilities of using geothermal heat in water of a similar or lower temperature. One may suggest that in such a situation, modernisation of the existing heating systems by replacing high temperature installations with low temperature ones would be most appropriate. The solution is, however, most often impossible – for many reasons. Therefore, decrease in temperature of the return water is another solution. Joining high- and low temperature installations is one of the solutions, too. Cascadeing various heat customers, requiring supply of a heat carrier of gradually lower and lower temperature is an example here. The authors have made a series of analyses aiming at defining the influence of combining high- and low temperature heating installations for improving the degree of geothermal energy utilisation in a heating plant with a bivalent set where the geothermal source is supported by a conventional peak load boiler (Nowak and Stachel, 1999, 2000a, 2000b, 2001a, 2001b). Geothermal energy production is based on a doublet operation pumping system. Geothermal water is pumped through a heat exchanger and its heat is passed to the district heating water. The analyses are interesting because they relate to the possibility of modernisation of the existing, developed high temperature heating systems by implementing a geothermal element and increasing the efficiency due to gradual constructing low temperature installations. The results of the analyses were discussed below, on the example of chosen solutions of geothermal heating plants. To evaluate the influence of using a low temperature heating element on the degree of geothermal energy utilisation with cascading groups of heat customers, it was assumed here that the heat produced in the central heat source is distributed to the consumers by means of the water main with the hot water circuit, which consists of the network supply-water pipeline as well as the network return-water line. The pipe network links the consumers with diversified heating systems. Some of those consumers have the conventional heating systems (the high-temperature ones) with

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the unit heaters, while others are connected to the low-temperature heating systems with the floor heating. Three different systems of combination of a geothermal power station with customers have been analysed. First a scheme of geothermal power station is presented in Figure 3. District heating water heated in the geothermal heat exchanger flows to two parallel groups of heat customers. After giving the heat to the two customers, water is mixed and flows to the geothermal reservoir. A characteristic feature of a described system is that the feeding temperature of both groups of heat customers is the same in both cases and corresponds to the temperature resulting from the regulation graph for radiator-type heating. On the other hand, the heating water temperature at the outlet from both groups of customers is differentiated and independent from external temperature, which occurs in both cases. The second system of the geothermal power station scheme is presented in Figure 4. This kind of installation can be found predominantly in newly designed and newly developed district heating systems with different, separated feeding of particular groups of low and high-temperature heat customers. In the presented system, heating water with different temperatures is directed to both kinds of heat customers. Temperature of heating water supplied to the radiator-type heating and floor-type heating results from regulation graphs corresponding to particular kind of heating.

High-temperatureheating system

Low-temperatureheating system

Heat exchanger

Peak-load boiler

sgm& , Tgz=Tpz

spm& , Tpz

sm& , Tgz

gV& , Tsp+2gV& , Tg

sm& , Tsw1

wm& , Tsw

gs WW && =

wm& , Tsp

sgm& , Tgp

spm& , Tpp

sm& , Tsp

um& , Tsp

Figure 3: Scheme of a geothermal plant with the network supplying two parallel joint

Figure 4: Scheme of a geothermal pl

groups of heat customers (variant I).

ant with the network supplying two parallel joint groups of heat customers (variant II).

gusg mm && − , Tgp

High-temperatureheating system

Heat exchanger

Peak-load boiler

Low-temperatureheating system

wm& , Tsw

gV& , Tg gV& , Tsp+2

gs WW && =

sgm& , Tgk

spm& ,Tpk

sgm& , Tgz sgm& , Tgp

spm& , Tpz spm& , Tpp

gum& , Tgp

gusp mm && + , Tspwm& , Tsp

pum& , Tsp

gum& , Tsw

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The third system of the geothermal power station scheme is presented in Figure 5. In the presented system the applicable heat distribution network feeds that network

supplying two

d, which results from the regulation graph for a given

The calculations allowed the preparation of charts presenting the influence of share of gree of geothermal heat production for various

and Stachel, 2000a). A sample chart for an

water to the heat customers, connected in series. It is assumed that the network water of the required temperature is first fed to the customers for the high-temperature heating and then to those for the low-temperature heating.

Peak-load boiler

Heat exchanger

Low- temperatureheating system

B

Figure 5: Scheme of geothermal plant operating jointly with a network groups of customers in a serial.

In all these cases, when the temperature of heating water beyond the heat exchanger is lower than requirekind of heating (i.e. radiator or floor-type), then a peak-load boiler is utilised, where heating water from the radiator-type heating or even floor-type heating attains the required temperature.

3 Results of the analysis

low temperature heating on the deparameters of geothermal water (Nowak installation with cascaded heating customers is presented in Figure 6. The chart for installations with a parallel connecting of heating customers is presented in Figures 7. The analysis of the achieved calculation results regarding the influence of the type of heating on the degree of geothermal energy utilisation proved that both serial and parallel connecting of customers with high- and low temperature heating is very reasonable in achieving improved cooling of district heating return water and thus more effective utilisation of geothermal energy. Along with increase in low temperature heating share in the total heat consumption, the degree of geothermal energy utilisation increases. So, variants with floor heating share as high as possible are most favourable. The influence of the type of heating on the degree of geothermal energy utilisation is more visible at low parameters of geothermal water withdrawal. If the geothermal water parameters (especially temperature) are high, the type of heating is not that significant as regards the amount of geothermal energy produced. The calculations proved that the maximum amount of geothermal energy might be used in the case of customers equipped only with low temperature heating installations with the assumed maximal temperature of geothermal water and the minimal district heating return water. The lowest utilisation of geothermal energy takes place when geothermal water has low temperature and heat consumption is not effective.

by-pass No 1by-pass No 2

gV& gV&gw1T gw2T

sg WW && =

sw1T

s1m&

sw2Ts2m&

spm&

sgpm&sg2m&

pwm&.varTgz =

.varTgp = sgm&

gppT

idem=°= C30Tpp

idem=°= C55Tpz

sw3T

AC

heatingsystem

High-temperature

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0

5000

10000

15000

20000

25000

30000

0 25 50 75 100Share of the floor heating in the total heat cosumption [%]

Geo

ther

mal

ene

rgy

[MW

h/a]

35000

Figure 6: Geothermal heat utilisation as influenced by the volume flow of geothermal water Vg, and the share of floor heating, for high- and low-temperature

) and return heating water (T ), for high- and low-temperature heating systems connected in parallel

tem trict heating return water decreases and, on the contrary, at low

peratures of geotherm

The paper presents the evaluation possibilities of the utilisation of geothermal energy perating with low- and high-temperature heating installations

heating systems connected in series (for temperature of geothermal water Tg = 75°C).

Vg = 50 [m3/h] Vg = 75 [m3/h]Vg = 100 [m3/h] Vg = 125 [m3/h]Vg = 150 [m3/h] Vg = 175 [m3/h]

0

10000

20000

30000

40000

50000

000

25 35 45 55 65 75

Temperature of geothermal water Tg [°C]

Geo

ther

mal

ene

rgy

[GJ/

a].

60

Variant-ITsp=25°CTsp=30°CTsp=35°CTsp=40°CVariant-IITsp=25°CTsp=30°CTsp=35°CTsp=40°C

Figure 7: Amount of geothermal energy possible for utilisation in a geothermal plant in function of temperatures: extracted geothermal water (Tg

sp(variant I and II).

In the case of high temperature geothermal water, the influence of the perature of the dis

tem al water and increase of the temperature of the district heating return water, the amount of energy produced decreases.

4 Conclusions

in geothermal plant co-oconnected in parallel and in series. On that basis, the following conclusions may be drawn:

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• detailed solutions and the effects of geothermal energy utilisation resulting from them, are closely dependent on local geothermal conditions and possibilities of the

• ture of the water taken from the ground and the

• mperature difference

• the ground and the minimal

•

•

are very few. A majority of buildings eating installations are supplied with heating water with

produced heat management, the amount of energy produced in the geothermal heat exchanger increases along with the increase of temperadecrease in temperature of the district heating return water, in areas of low temperature of geothermal water, heat customers have a significant influence on the amount of energy produced. Small tebetween the district heating return water and the geothermal water allows for using the source potential to a very small extent, geothermal energy may be used to the largest extent in case of floor heating at maximal temperature of the water taken fromtemperature of the district heating return water. The smallest utilisation of geothermal resources is when geothermal water is of low temperature and heat consumption is not effective (high temperature of the return water), replacing high temperature heating with low temperature heating, particularly at lower geothermal water temperatures is a favourable solution,

• analysis of operation efficiency for a geothermal plant supplying two groups of heat customers presents the variant of the biggest possible share of floor heating as the most favourable. Floor heating, owing to the low temperatures of the return water, increases the efficiency of a geothermal plant significantly. But floor heating is maybe the most expensive alternative to increase the cooling of the district heating water. It is good, and pleasant, but expensive. a situation when a geothermal plant has a district heating network divided into a low- and high temperature heating system is a favourable solution.

5 Supplement In Poland low-temperature heating installationswith remote central htemperature range as high as 95/70°C, where the first value regards the supply water temperature whereas the second one pertains to the return waters from the heat customers. These values correspond to so-called minimum external calculation temperature, which in the case of Szczecin is -18°C. Temperatures of supply heating water as well as the return water vary with external temperature. According to Polish calculation standards traditional heating systems have been designed (and still are) to conform to such extreme parameters of heating water. In the case of large heating installations, encompassing large numbers of customers of heat supplied by the thermal power stations the heating water delivered to local heat distribution networks, the heating water has temperature of 150/70°C. In such exchange stations there takes place a transfer of heat from the heating water to the water circulating within the building, which has extreme temperature of 95/70°C. In Poland municipal district heating installations are very extensive and for example in Stargard the total length of the transmission networks in over 44,4 km, heat is delivered to about 1000 buildings (customers) and the thermal power station power is 98,9 MW. A similar situation holds in a majority of towns, where there is a possibility of utilization of geothermal resources for heating purposes. Due to a fact that Polish geothermal resources are characterized by a low or medium enthalpy the possibilities of utilization of their energy in existing heating installations are rather limited. Available for utilization is only that part of energy, which results from the

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temperature surplus of extracted geothermal water to the return heating water from the heat customers. In the majority of cases concerned with the development of geothermal power plants it would be ideal if a complex modernization of heating installations in buildings (heat customers) was possible as well as transition to the low-temperature heating systems. Due to massive costs of such operation such solution cannot be considered, at least at the present economical situation of Poland. Therefore under Polish conditions the geothermal power can be utilized in a majority of cases as the supplementary source of energy aiding the conventional heat sources. Such status can be improved by implementation of for example heat pumps in power stations. Such situation can also be improved by incorporation of low temperature heating installations (60/30°C) to the existing ones (95/70°C). This leads to a reduction of the return heating water temperature going to the geothermal heat exchanger. Such issues have been discussed in the principal part of that paper. The described concepts of the improvement of the degree of utilization of the geothermal energy in existing heating installations, stem from the parameters of Polish geothermal waters as well as the specifics of high-temperature heating installations. The problems of operation between the geothermal well and the heat customers are most pronounced on the examples of existing geothermal power plants in Poland. For example, the geothermal power plant in Pyrzyce uses the geothermal water with temperature of 63°C, geothermal power plant in Mszczonow – water with temperature of 41°C, whereas the heating installations in buildings are designed for heating water at 95/70°C. This gives rise to several operational, technical and economical problems (Meyer and Szaflik, 2001). The present paper is an attempt to provide answer to such problems.

6 References Gorecki W. i inni (Towarzystwo Geosyn

1966). Atlas zasobów energii geotermalnej na Niżu Polskim, optyków GEOS, Kraków.

ków. Grant KBN 7TO7G-010-10,

Slovaka, 3(2001), pp. 429-434.

dings of the International Conference:

yd. Uczelniane Politechniki Szczecińskiej,

f the water in small heating systems. Acta Mechanica Slovaka, 3(1999),

l-energy use in the central heat source. Acta Mechanica Slovaka,

Kabat M., Nowak W., Sobanski R. (1999). Zasady wykorzystania energii wód geotermalnych do celów ogrzewczych budynSzczecin. Kabat M. (2001). Integrated systems for utilization of renewable energy. Acta MechanicaMeyer Z., Szaflik W. (2001). Geothermal heating plant in Pyrzyce – current cooperation with heat consumers. ProceeRenewable Energy Sources on the Verge of the XXI Century, Warsaw, pp. 226-232. Ney R., Sokolowski J. (1987). Wody geotermalne Polski i możliwości ich wykorzystania, Nauka Polska, 6(1987). Nowak W., Sobanski R., Kabat M., Kujawa T. (2000). Systemy pozyskiwania i wykorzystania energii geotermalnej, WSzczecin. Nowak W, Stachel A. (1999). Influence of parameters of geothermal water on utilisation opp. 187-192. Nowak W, Stachel A. (2000a). Analysis of the floor-heating influence on the degree of geo-therma3(2000), pp. 417-422.

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Nowak W, Stachel A. (2000b). Ecological estimation of work of a geothermal heating plant. In: Proceedings of the ASME International Thermal Science Seminar, pp. 522-528, Bled. Nowak W, Stachel A. (2001a). Evaluation of effectiveness of utilization of geothermal energy in the heating systems with the parallel-connected heat customers and a quality governing. Acta Mechanica Slovaka, 3(2001), pp. 321-326. Nowak W, Stachel A. (2001b): Modelling of thermal-hydraulic processes of geothermal energy extraction and utilisation. Transactions of IFFM, (109) 2001, pp. 45-57. Sobanski R., Kabat M., Nowak W. (2000). Jak pozyskać ciepło z Ziemi, COIB, 2000. Sokolowski J. (1997): Metodyka oceny zasobów geotermalnych i warunki ich występowania w Polsce, Materiały Polskiej Szkoły Geotermalnej, PGA i CPPGSMiE PAN, Kraków. Wisniewski G. (1997): Odnawialne źródła energii, [w] Wybrane zagadnienia polityki energetycznej Polski, Polski Klub Ekologiczny, Warszawa.

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Recent large scale ground-source heat pump installations in Ireland

Sarah O’Connell and Stephen F. Cassidy1

Mechanical & Manufacturing Engineering Dept, CIT, Cork, Ireland Email: [email protected], [email protected]

Abstract

This paper examines the effectiveness and suitability of Ground Source Heat Pump technology for the Irish climate. The success of the installations to date is evaluated in the areas of operation of overall system, environmental benefits and financial benefits accrued. Geothermal resources in Ireland are mainly low temperature. As a result of this, geothermal energy is used for heating and cooling of buildings as there is insufficient resources for electricity generation. Ground Source Heat Pumps are mainly used for heating, as there is little need for summer cooling. While there are over 500 domestic installations in the country it is only recently that large-scale projects have been introduced. Buildings in both urban and rural settings are looked at. Building types range from swimming pools to office buildings. The performance of ground source heat pumps in large-scale applications has been excellent. There are significant reductions in CO2 emissions. Payback periods are 4-6 years despite installation costs being high. More installers and a reduction in heat pump costs could reduce installation costs.

Keywords: Ground-source heat pumps, Ireland, case studies.

1 Introduction Thermal energy consumption in Ireland is 1.032 Mtoe (155.67 TWh) for domestic heating. For the tertiary sector it is 0.421 Mtoe (63.50 TWh) (Dubuisson 2002). Less than 1% of Irish households are heated using a heat pump. This contrasts sharply with Switzerland, one of the world leaders in heat pump technology, in which 67% of homes are equipped with a heat pump (Rybach and Sanner 2000). The reasons for such a low number of installations in Ireland is due to a) low public awareness of heat pump technology and its advantages over conventional heating systems, b) air conditioning, which drove the heat pump market, especially in the US, is not required in Ireland, c) a lack of hot springs, a feature which usually promotes the use of ground source heat pumps (GSHP) and d) few installers to promote and install heat pump systems. There are between 500 to 600 domestic ground source heat pump installations in Ireland, typically in the range between 10 and 14 kW. Presently, there are approximately 17 large-scale commercial systems installed (Sikora 2002). The installed thermal capacity in Ireland is 6-7 MWt. This paper deals with these large-scale commercial installations that have an output larger than 12kW. This figure was chosen so direct comparisons with other countries could be made using the data compiled by Lund and Freeston (2000) in their assessment of global geothermal energy. While the number of GSHP systems currently installed in Ireland is low, there appears to be a large potential for growth in the area due to the prevailing climatic and soil conditions. Ireland has a mild climate due to the proximity of Gulf Stream currents in the Atlantic Ocean. The average annual air temperature is 9°C. The lowest mean daily minimum temperature in winter is 2.5°C. The country has both a high 1 Corresponding author.

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rainfall rate, 800 to 2,800 mm per annum, and high relative humidity values are between 71% and 91% (Met Eireann 2002). These factors combine to ensure a large moisture content in the soil thereby increasing its thermal conductivity. Saturated soil has a thermal conductivity value up to four times greater than dry soil. The overall geological composition in Ireland, 40% of parent soil composition at depths of 1m and greater consists of either Sandstone or Limestone (Gardiner and Radford 1980). Sandstone has a thermal conductivity of between 1.28 W/mK and 5.10 W/mK. Limestone has thermal conductivity between 1.96 W/mK and 3.93 W/mK. Average ground temperatures at depths of 1m and greater are between 9oC to 13oC (Connor 1998). Horizontal collector ground loops may thus be used in Ireland, as the collector will not encounter external frost since diurnal damping depths are 0.2 m for sandstone, and 0.1 m for damp soil consisting of organic matter. This, together with the easy availability of land and the cheaper installation cost over conventional vertical borehole collectors, means that horizontal collectors are the most common form of collector type used.

Installed Capacity (MWt)

0

100

200

300

400

500

Switzerl

and

Sweden

German

y

Austria

Finlan

d

France

Poland

Lithu

ania

Bulgari

a

Netherl

ands

Czech

Rep

ublic

Irelan

d (es

t)

Norway

Serbia

Hunga

ry

Denmark

Sloven

ia

Slovak

Rep

ublic Ita

ly UK

Greece

MW

t

Figure 1: Installed Ground-source Heat Pump capacity in Europe. (Lund and Freeston 2000).

Installed ground-source heat pump capacity for Europe is shown in Figure 1. Total European installed capacity is 1,577 MW of which the estimated installed capacity for Ireland is 3.7 MW. The European annual growth rate is 15% (Rivoalen 2001). Geothermal heat pump installations in the US have total capacity of 1,356 MW, comparable to the whole of Europe and are expected to increase at a rate of 10% annually (Lund and Freeston 2000). The estimated Irish annual growth rate is 30%. The high Irish growth rate is due to the lack of maturity in the heat pump market.

2 Recent large scale GSHP installations in Ireland The following is an analysis of installations that have been recently installed in Ireland. Most have been extremely successful and indicate that ground-source heat pumps are well suited to the Irish climate. The majority of these large scale installations have been in showcase buildings which feature a range of renewable energy technologies such as solar panels for hot water heating, sustainable building design and layout and natural ventilation. Table 1 gives a summary of these installations.

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Table 1: Commercial GSHP installations in Ireland.

Building Location Building Type InstalledCollector Type

Collector Length (m)

Heat Pump (k W) COP

Payback period (years)

Estimated % CO2 Emissions Reduction

Trinity College, Dublin (out of commission)

4 University buildings

Aquifer Boreholes (solar add-on)

4 x 12 6 Heat Pumps 450 kW

~ 4 1.5 - 4 60

Motor Tax Office, Tralee, Co. Kerry

Office 1999 Horizontal Closed Loop

5100 130 kW

3.7 4 52 (B. & E. M. 2001)

Share Hostel, Cork.

Residential 2002 Shallow Aquifer Borehole

20 100 kW 3.5 30

Mallow Swimming Pool, Co. Cork

Swimming Pool

1987

Geothermal Aquifer Borehole

75

100 kW 4

11.5

Carbery GAA, Co. Kildare

Sports Hall 2003 Direct Expansion Horizontal

440 46 kW 6 (max)

Dolmen Centre, Co. Donegal

Sports Complex 2000 Horizontal Closed Loop

1800 45 kW ~ 3 45

Marlton House, Wicklow Town

Residential with Swimming Pool

Horizontal Closed Loop

2800 40 kW 3.5 6 - 8 45

Sports Centre Churchfield, Cork

Sports Complex 1997 Horizontal & Vertical

600 Horiz 120 Vert

34 kW

2.37

Camp Hill Community, Callan, Co. Kilkenny

Residential Care Facility

1996 Artesian Well & Tubing on Roof

30 kW 3.5 6 - 8 45

Spiddal, Co. Galway Private dwelling &swimming pool

2001 Horizontal Closed Loop

1500 30 kW 3.5 6 - 8 45

An Seanscoill, Co. Galway

Old School House Horizontal Closed Loop

1500 30 kW 3.5 6 - 8 45

Caheroye House, Athenry, Co. Galway

Country Hotel 2002 Horizontal Closed Loop

1500 30 kW 3.5 6 - 8 45

Navan, Co. Meath

Private dwelling & Offices

2000 Pipe in stream Closed Loop

1500 30 kW 3.5 6 - 8 45

Briar Hill Large Private Dwelling

1500 30kW 3.5 6 - 8

Landfill Site Office, Kinsale Road, Cork.

Office

2000

Horizontal Closed Loop

2400 28 kW

3.5

4.5 - 6 30

Pairc Gno an Daingan, Co.Kerry.

Technology Park Offices

2002 Horizontal Closed Loop

960 26 kW

Green Building, Temple Bar, Dublin

Apartments / Office / Retail

1994

Vertical Borehole

150

23 kW

4.87

2.5

86 (Cooper 1995)

Heritage House Ballyhooley, Co.Cork

Residential Listed building

1995

Air & Horizontal in compost

1050 19 kW 3.3 – 3.6

6 45

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Horizontal collectors are the preferred option as vertical boreholes are 4-5 times more expensive to install in Ireland than horizontal systems (O’Brien 2002). The horizontal collectors have all been installed at a depth of 1 m with the exception of the Churchfield installation, which was installed at 0.5 m depth. Ireland is not a densely populated country with only 52 persons per square kilometre thus accounting for the availability of land to install horizontal collectors. Typically ¾ inch diameter pipe is laid in parallel and manifolded together. The borehole collector at Mallow Swimming pool uses the Mallow geothermal aquifer as its source. The water from this aquifer has an average recorded temperature of 19oC. The borehole at Churchfield was installed to compare its performance with that of the horizontal collector. The horizontal loop proved to be more efficient. A vertical borehole was chosen for the Green Building in Temple Bar due to space restrictions. Some seepage from the bedrock also increases the heat pump COP. The decomposing waste at the Kinsale Road Landfill site is used as the heat source for the Administration building. The Share Hostel in Cork uses the Lee Valley aquifer, which, due to the heat island effect, has a water temperature of 12-13oC. The collector installed in Navan was placed on a streambed and consists of stainless steel piping. Where possible, favourable geophysical features have been used for the collector, for example, the artesian well in Callan, Co. Kilkenny. In theory this should improve the system performance, however, the systems have not been monitored so the reduction in energy consumption has not been quantified. The 5 heat pumps installed in Trinity College, Dublin range in size from 50 kW to 150 kW. The 30 kW systems are a standard size and the associated horizontal collectors are 1500 m in length. Tralee Motor Tax office is the largest installation serving a single building.Mallow Swimming pool payback period is significantly higher because the project was the first of its kind in the country and encountered much higher exploration costs to determine the heating potential of the aquifer. For the Green Building in Temple Bar, the payback period for the entire building is estimated to be 18 years. As ground source heat pumps are a much more commercially attractive solution than other forms of renewable energy, they have a significantly shorter payback period than the building as a whole. For the Tralee Motor Tax office, the payback period was good due to its use for both heating and cooling. This can be accounted for by the very low running costs for the GSHP system. For example, in February 2001, heating costs amounted to approximately 15 euros per week. For the Tralee Motor Tax office, CO2 emissions were reduced by 52% as compared with a BRESCU type-3 office building. For the entire Green Building in Temple Bar, the reduction was 86%. This reduction was enhanced by the inclusion of foliant species as well as other renewable energies. The heat pumps in Trinity reduced CO2 emissions by 920,000 kgCO2/kWh annually. In Churchfield, a natural gas fired boiler is running continuously so there is a neglible reduction in emissions. CO2 emissions for the other buildings have been estimated based on heat pump annual energy consumption and using BRECSU CO2 emissions indicators (BRECSU 2000). The 45% reduction is based on a comparison with an oil-fired boiler while the 30% reduction is based on comparison with Natural Gas where it is available. Future projects include geothermal heating systems for Nursing home and health care projects with floor areas between 1200-1800m2 in planning or progress. The Ballymun regeneration project in Dublin plans to install ground-source heat pumps in five houses to evaluate their practicality in high-density urban dwellings (Sikora 2002). Macroom Environmental Industrial Estate is a project initiated by Cork County Council. The pilot building will use an open loop water source heat pump to

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provide heating for the building. A 200kW system is under construction for University College Cork utilising boreholes in a gravel aquifer. Inniscarra Environmental offices will have a buried horizontal loop installation with a proposed total heat output of 42kW, due to start on site in Sept 2003.

3 Discussion Running costs for GSHP systems in Ireland are significantly lower than other forms of heating. For example, a domestic oil boiler has running costs 66% greater than a ground-source heat pump. However, the high initial investment may be a deterrent to prospective users. Installation costs are 40% greater than oil or gas fired boilers, the most common forms of residential space heating, and 50% greater than electric storage heaters (O’Brien 2000). This is largely due to the lack of competition installing ground-source heat pump systems and the high cost of heat pump units. As the environmental and cost saving benefits of ground-source heat pumps becomes more widely known, this should encourage growth in the market and so reduce the initial installation costs. Organisations such as The Geothermal Association of Ireland, Sustainable Energy Ireland, and government funded Energy Offices at both national and local level are raising the profile of ground-source heat pumps in Ireland. The increasing urbanisation of Ireland will require GSHP installations to become more compact. An alternative to borehole heat exchangers is to install the collector under or in building foundations. This technology has never been applied in Ireland although it has been developed extensively in Austria mainly using foundation piles containing HDPE piping with brine as the heat transfer fluid. Collector piping has also been installed in raft foundations and diaphragm walls (Brandl 1998). This technology has also been implemented in Canada for a 211 kW heat pump capacity system under an office building (Caneta 1999) and in the US for a 6-ton (21kW) sub-slab heat pump installation (Drown et al. 1992). A project is currently underway at Cork Institute of Technology to install a collector under the footprint of a building (O’Connell in prep.). The aim of this project is to demonstrate the technical and economic feasibility of locating collectors in the foundations of buildings in Ireland. This, it is hoped, will make the use of GSHP in the urban environment more widespread in Ireland. Ireland exceeded the maximum permissible greenhouse gas emission target set by the Kyoto protocol at 13% over 1990 levels in 1999. To limit energy related CO2 gas emissions, renewable energy may be used to reduce emissions of CO2 by over 4.25 million tonnes, which is over 35% of Ireland’s target (Kellett 2002). Ground-source heat pumps may contribute greatly to this reduction as they reduce CO2 emissions by between 30% and 100% as compared with conventional heating systems (Dubuisson 2002).

4 Conclusions and recommendations The majority of the projects detailed in this paper have received funding incentives from local, national or EU level. It is hoped that these buildings will demonstrate the commercial viability of ground source heat pumps to the wider public and so increase the take up of this technology. The potential for ground source heat pumps in Ireland is extensive. At present the percentage of heating requirements met by heat pumps is insignificant. The potential primary energy savings for residential and tertiary sectors is 2,426 TWh/year equivalent to 80,000 units as estimated by Sustainable Energy Ireland. These would reduce CO2 emissions by 617000 tonnesCO2/year and the

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primary energy requirement for heating would be cut by 5%. The extra investment required would be 602.6 million euros (Dubuisson 2002). The barriers preventing this potential from being realised include: higher capital cost of GSHP systems; higher perceived risk; price distortions (external cost of fossil fuels, subsidies for infrastructures); unfavourable market characteristics; lack of installation experience; absence of quality standards and, finally, low level of awareness among the general public and decision makers in government and county councils. To encourage greater use of GSHP systems, the following measures should be undertaken:

• Subsidies for installation of domestic heat pumps as well as the existing subsidies for developers.

• Certified installers. • Standards for new building codes with regard to technical/economic

considerations for heat-pump installation. • Standards for use of heating and cooling systems in buildings with air

conditioning. • Restrictions on use of fossil fuel and direct electricity heating. • Carbon fuel tax. • Continual research and development of heat-pump systems specially designed

for conditions in Ireland.

Acknowledgements Funding received from the HEA under PRTL Cycle II Environmental Research Institute – New Energy Systems in Buildings. The author would also like to thank Dunstar Ltd (Clonakilty, Co. Cork) for technical expertise and information shared.

5 References Brandl, H. (1998). Energy Piles for heating and cooling of buildings. Seventh International Conference & Exhibition on Pilling and Deep Foundations, Vienna, Austria. BRESCU (2000). Energy Consumption Guide 19 – Energy use in offices. UK Government Energy Efficiency Best Practice programme BRESCU. Building and Energy Management (2001). Energy Survey Report of Motor Tax Office, Tralee, Co. Kerry. Report for Malachy Walsh & Partners, Cork, Ireland. Caneta (1999). A Ground Source System at the Trustcan Realty Office. Report for Centre for the Analysis and Dissemination of Demonstrated Energy Technologies (CADDET), Canada. Central Statistics Office. (1996). Principal Statistics - Demography and Labour Force. Irish CSO statistics available at http://www.cso.ie/principalstats/pristat2.html#figure1 Connor, B. P. (1998). National Survey on Low Temperature Geothermal Energy. Geothermal Association of Ireland Newsletter. Issue no. 1 pp. 3. Collins, C. (1998). Development of a Geothermal Heat Pump Test Facility. Masters Thesis, Department of Mechanical and Manufacturing Engineering, Cork Institute of Technology.

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Cooper, T. (1995). Use of energy efficient technologies to minimize fossil fuel derived energy in a landmark building. Project report for Green Building Temple Bar. Trinity College, Dublin. Cork Corporation. (2002). Knockfree geothermal project. Internal report, Cork City Energy Agency, Cork. Dohan, F. (2002). The Dolmen Centre. Personal correspondence, Portnoo, Co. Donegal. Drown, D.C., Kast, T.P. and Den Braven, K.R. (1992). A ground coupled storage heat pump system with waste heat recovery. ASHRAE Journal, Vol.35, pp. 20-24. Dubuisson, X. (2002). Sun in Action – The Sustainable Energy Revolution. Presentation to Irish Solar Energy Conference, June 2002, Tralee, Co. Kerry, Ireland. Dunstar Ltd. (2000). System description and operation manual for Solterra Geoenergy System using a York YCWM 120 Heat Pump. Operating Manual for Tralee Motor Tax Office, Co. Kerry, Ireland. Gardiner, M.J., Radford, T. (1980). Soil Associations of Ireland and their land use potential – explanatory bulletin to soil map of Ireland 1980. Soil Survey Bulletin No. 36. National Soil survey of Ireland, An Foras Taluntais. Kellett, P. (2002) Irelands Natural Energy Opportunity: See the Light – No Bills from the Sun Presentation to Irish Solar Energy Conference, June 2002, Tralee, Co. Kerry, Ireland. Lund, J.W., Freeston, D.H. (2001). World-wide direct uses of geothermal energy 2000. Geothermics, Vol. 30 pp. 29-68. Met Eireann. (2002). www.meteireann.ie/climate/. O’Brien, M. (2002). Presentation to the Institute of Leisure Management March 21st 2002: Geothermal and Other Alternative Energy Uses in Cork Leisure Facilities. Cork City Energy Agency, Cork, Ireland. O’Brien, M., McGovern, C. and Walsh, M. (2000). Geothermal Energy Utilisation in Cork City. Geothermal Association of Ireland Newsletter. Issue no 3 pp. 4–6. O’Connell, S. (in prep.). Renewable Energy in Buildings – Ground Source Heat Pumps. Masters project in progress, Department of Mechanical and Manufacturing Enginering, Cork Institute of Technology, Ireland. Rivoalen, H. (2001). Heat Pump Market Overview in Europe. Report for EDF Research and Development group on Heat Pumps, Air Conditioning and Indoor air quality. Rybach, L., Sanner, B. (2000). Ground – Source Heat Pump Systems the European Experience. GHC Bulletin, March 2000. pp. 16–26. Sikora, P. (2002). Technology and illustrative Large Scale Installations. Personal correspondence, Dunstar Ltd, Clonakilty, Co. Cork.

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Balneological prospects in Iceland using geothermal resources

Hrefna Kristmannsdóttir1) and Ólafur Grímur Björnsson2)

1)University of Akureyri, Solborg, Nordurslod, 600 Akureyri, Iceland, 2)National University Hospital, Hringbraut, 107 Reykjavik, Iceland

E-mail: [email protected]

Abstract Balneotheraphy has been practiced all over the world from early history. In Iceland bathing in geothermal pools was popular for recreation from early settlement some 1100 years ago. The Icelandic Sagas written in the thirteenth century report the use of geothermal bathing for balneotheraphy to ease rheumatic pain. In modern Iceland the Health and rehabilitation clinic in Hveragerði and the Blue lagoon spa by the Svartsengi power plant are the main balneological resorts. Further prospects to build several spas and health resorts appear to be very promising in Iceland. The geothermal waters are of varied chemical composition, there are ample resources of uncontaminated spring water and clean air as well as magnificient scenery. Further there is access to geothermal clay and precipitates as aid in balneotherapy treatment. The local food supplies are also very fresh and free for contamination and the health care system is of high quality. More research is needed as well as enforced market survey and enforcement of the service needed for the varying market targets. Classification of Icelandic geothermal water reveals that sulfide water, fluoride water and saline waters are commonly encountered. Iron rich water is rather rare and iodide water and radioactive water has not been found. Mineral water suitable for drinking is not uncommon. Saline geothermal water resources encountered at several localities in Iceland bear resemblance to that of famous Spa localites as Baden-Baden in Germany. Among those are Seltjarnarnes, a suburb of the capital city Reykjavík, the small towns Stykkishólmur and Húsavík as well as some localities in rural areas of the country.

Keywords: balneology, balneotheraphy, geothermal pools, classification of Icelandic geothermal water, spa, resources.

1 Introduction There is a long tradition in Iceland for the use of geothermal baths as entertainment, relaxation and also for rehabilitation and curing of rheumatism and other illnesses. There has been an interest for a long time to build out the tourist industry to include balneotheraphy (Checci and comp., 1975), but so far there has been a rather slow growth rate and no big projects have been launched in the last years in spite of considerable interest of the government and private investors. Geothermal activity is widespread in Iceland (Björnsson et al., 1990) and the resources are varied both in temperature and chemical properties. The geothermal fields are classified as high-temperature geothermal fields and low-temperature geothermal fields according to the base temperature at 1 km depth. The high-temperature fields have temperatures exceeding 200 °C , but below 150 °C in the low-temperature geothermal fields.The high-temperature geothermal fields are all located within the active volcanic zone and closely related to volcanic centers, whereas the low-temperature fields are found in older geologic settings. There are available data of the chemical compostion of spring water, gas and steam from fumaroles and fluids from wells from most of the geothermal fields in the country (Kristmannsdóttir, 1990, 1992). The data span over long time interval and are

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of varying quality, some are published and some are contained within official and privately owned data banks. Data of cold water are much more scarce as many of the private and municipal waterworks are fairly small and have not had the means to make chemical analysis of the waters according to quality assurance criteria. The first step in building up a balneological industry is to define the resources, physical and social. This entails the classification of geothermal waters, checking the availabilty of mineral water, clay deposits and geothermal precipitates, the purity of the air and potable water as well as the available medical service, and recreation. The next steps are to make market analyses and then to define business projects based on results from those two primary steps. A part of the resource definition as well as the definition of a business project is to designate the kind of balneoteraphy possible for the type of waters and other resources accessible. This requires a close cooperation of specialists from different fields; geoscientists, medical doctors and people educated in economics. In this paper an effort to classify the resources is described and some primary steps taken on the way to maket analysis and project definitions.

2 Chemistry of icelandic geothermal waters Geothermal water in Iceland is in most cases of meteoric origin and only in a few places sea-water originated. In general the salinity of Icelandic groundwaters is in direct relation to the distance from the ocean (Fig. 1) The low-temperature geothermal waters are generally very diluted, with typically 200-400 mg/l, of dissolved solids (TDS) and gases, but the mineralization increases by increased reservoir temperatures. In the non-saline high-temperature geothermal waters TDS exceeds 1000 mg/l. A few fields are either sea-water contaminated or the waters seep through sediments formed in sea-water. Their salinity is most commonly less than 10 % that of of sea-water. On the Reykjanes peninsula, in SW Iceland and in Öxarfjördur in NE Iceland (Fig. 2) there occur waters with much higher salinity, up to that of normal sea-water (Kristmannsdóttir and Ólafsson, 1989). The dominant reservoir rocks in the Icelandic geothermal fields are basaltic lavas and hyalo-clastites and the fluids evolved by reaction with such rocks at elevated temperatures have high pH values. Acidic igneous rocks are encountered within the central volcanoes, past and present, but account to about 10 % of the total volume of rock formations in Iceland. The pH values are typically 9-10 for the low-temperature waters, but lower for the high-temperature geothermal waters due to their higher concentrations of acidic gases. Waters with extremely high pH, about or even exceeding 11 are also encountered, especially on the boarders of the active volcanic zones in SW and NE Iceland where young, glassy, basalt lavas, which are highly reactive, are common in the underground reservoir rocks (Fig. 3). The geothermal waters are in equilibrium with silica minerals, alkali-, iron-, magnesium and aluminium silicates, calcium carbonate and metal sulfides and oxydes (Arnórsson et al., 1983, Kristmannsdóttir, 1990). The silica concentration of the waters is in direct relation with increasing temperature, carbonate concentration is in inverse relation to increasing temperature and the waters are highly depleted in magnesium, even at moderate temperatures. The waters are devoid of dissolved oxygen and the gas phase is mainly constituated of nitrogen and minor argon as well as carbon dioxide and hydrogensulfide. Waters reacting with acidic rocks will contain somewhat higher chloride concentration than those reacting with basaltic rocks and also have higher concentrations of fluoride, boron, lithium and radioactive elements. In general all the elements, which are not bound in the minerals of the basaltic rocks, will be concentrated in the acidic rocks

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and hence in the waters reacting with them. Other elements as iron, manganese, copper, cobolt and zink will be more enriched in the basalts and therefore also in the waters reacting with such rocks. The mineral concentrations of the waters will also be highly dependent on the age and weathering and alteration state of the rocks. The high temperature geothermal waters are much more mineralized due to increasing solubility by increased temperature of most of the minerals determining the water-rock equilibrium in the geothermal systems. As in the case of the low-tempera-ture waters there do exist geothermal brines, mainly on the Reykjanes peninsula. Reaction with basaltic and acidic rocks affects the high-temperature geothermal waters in a similar way as at lower temperatures. The high-temperature geothermal fields offer a great variability in water chemistry of associated spring water by the addition of steam to either the boiled and cooled geothermal water or to cold spring water. By the variation of those components waters with a range of pH and mineral concentration can be created.

3 Balneological classification of Icelandic waters The Icelandic geothermal waters have been classified by their chemical character and balneological properties (Kristmannsdóttir et al., 2000, 2001) using a classification slightly adapted for Icelandic conditions but based on both German (Fresnius and Kuβmaul, 1998) and Japanese (Agishi et al., 1995) classifications for health resort water. The classification groups are: 1. Carbonate water containing total carbonate (calculated as CO2) in excess of 300 mg/l 2. Sulfide water containing H2S in excess of 1 mg/l and of temperature > 40 °C. 3. Highly mineralized warm (>40 °C) waters with TDS (total dissolved solids)

exceeding 1000 mg/l. 4. Iron rich water containing iron in excess of 20 mg/l and of temperature > 40 °C. 5. Fluoride water containing fluoride in excess of 2 mg/l and of temperature > 40 °C. 6. Iodide water containing iodide in excess of 1 mg/l. 7. Radioactive water containing radon in excess of 666 Bq/l . In Iceland carbonate waters (Fig. 4), both thermal and cold waters, are most common in the Snæfellsnes peninsula (Arnórsson, 1982, Arnórsson and Barnes, 1983). The carbon dioxide of both the thermal and cold waters is believed to have a different origin from the waters and be derived from deep seated intrusions or the mantle. All high-temperature waters are carbonate waters. Carbon dioxide springs commonly occur on the outskirts of high-temperature geothermal fields and are formed by either mixing of hot and cold water or by steam heating of shallow cold groundwater. The sulfide waters (Fig. 5) are encountered in all high-temperature geothermal fields and many low temperature fields especially in younger geological formations. The highly mineralized waters (Fig. 2) are either saline (brines), carbonate or high-temperature waters. Iron rich water is not common in Iceland and mostly associated with carbonate waters. Fluoride water is rather common (Fig. 6) and often associated with central volcanoes, high-temperature geothermal fields and acidic reservoir rocks. Iodide waters have not been encountered in Iceland. The radioactivity of the thermal waters has not been studied in any detail. Radon in Icelandic geothermal waters has been monitored in the aim to forecast earthquakes (Hauksson and Goddard, 1981) and to map the flow pattern in geothermal fields (Ármannsson et al., 1982). The limited data existing indicate a relatively low concentration of radon in Icelandic waters,

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which is not unexpected in light of the low concentration of radioactive elements in the Icelandic rocks (Poliakov and Sobornov, 1975). A correlation between chemical classification and balneological properties is not always a straightforward task and it appears that in spas different water types have been used for the treatment of many diseases (Björnsson, 2000, Agishi et al., 1995). Balneotherapy is an alternative treatment often used for uncurable illnesses and when an effective medicine is discovered it will mostly replace the balneotherapy methods. Many Icelandic waters of the groups 1, 2, 3 and 5 above are similar to those of renowned foreign spas and have already proved to be effective in the treatment of skin diseases and reumatism. Further study of their effectiveness in treatment of other ailments remains to be made.

4 Other available resources Hydrothermal clay deposits, silica precipates and steam sublimates, which are of importance for balneological uses, are usually readily available at the sites of high-temperature geothermal fields. The mining of hydrothermal clay in situ is usually rather difficult due to the inhomogenity of the deposits and mixing with other hydrothermal deposits. Some places like in Hveragerdi, which is one of the Hengill high-temperature fields, the clay has been redeposited and enriched and is therefore easily mined. There it has been utilized for a long time in Icelands oldest spa resort (Gunnarsson, 1998). Mapping of Icelandic clay deposits, hydrothermal and sedimentary, is still rather incomplete and needs to be enforced. Most places in Iceland there are ample resources of fresh and uncontaminated potable water, even though their documentation might be improved. Likewise the atmospheric air is clean, healthy and fresh. The nature is magnificent and the environment peaceful. The cousine is rather tasty and based on good and uncontamined local food provisions. The national health care system is good and in the larger towns there are high-tech hospitals providing first class treatment for all kinds of illnesses. The possibilities offered for recreation are ample.

5 Comparison with other countries As compared to geothermal waters in other countries the waters in Iceland are generally much less mineralized although there are geothermal brines and highly mineralized waters in a few places (Fig. 2). The thermal waters in central Europa are much more highly mineralized than typical low-temperature geothermal waters in Iceland, but some low-temperature brines in Iceland are rather similar to water in many European health resorts like Baden Baden (Björnsson, 2000, Kristmannsdóttir et al., 2000). The existing data indicate that the concentration of radon in Icelandic waters is very low as compared to values in other European countries. Geothermal waters in Japan (Hotta and Ishiguro, 1986) are varied in composition and many are quite comparable in composition to waters in Iceland, especially in the high-temperature geothermal fields. Geothermal bathing is traditional in Iceland from early settlement some 1100 years ago and the Icelandic sagas written in the thirtieth century report “going to baths” as a popular entertainment and also as treatment to ease rheumatic pain. Nowadays the average Icelandair uses the swimmingpools as an everyday recreation and relaxation enjoying more numerous swimmingpools per capita than in any other country. Spa treatment however is not as popular nor common in Iceland as in many European and Asian countries.

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6 Places of special interest On basis of the primary market analyses and definition of some possible business projects based on the classification of geothermal waters, definition of other resources and appraisal of the kind of balneoteraphy possible for the type of waters (Björnsson, 2000) some places of special interest for the building of health spas have been pointed out. All the high-temperature geothermal fields offer great variability in the possible water/bath composition as steam or condensate addition to the hot water or even to cold water will give a broad spectrum of different water composition. At the sites there will generally be ample deposits of geothermal mud, clay and silica deposits. The main places of interest are the ones located near densely populated areas like the Reykjanes, Svartsengi, Krísuvík and Hveragerði fields in SW Iceland and the Námafjall field in NE Iceland (Fig. 2). The Blue lagoon spa in the Svartsengi field (the Blue lagoon committee, 1996) has become one of the main touristic trademarks of Iceland and is renowned for effective treatment for psoriasis (Ólafsson, 1996). In Hveragerði the Health Clinic of the Nature health Association of Iceland was established in Hveragerdi in 1955 with preventive measures in view. “The clinic is only a short walk from the mineralrich, geothermal mud pools which provide the essential ingredient for its mud baths, a miracle in alleviating the joint pains common to arthritis." (Gunnarsson, 1998). Reykjanes and Svartsengi are brine fields whereas in the Krísuvík and Hveragerði fields the waters are not very saline. In northern Iceland the Námafjall high-temperature, freshwater geothermal field is a quite interesting site, beeing near great turist attractions, well known and studied and some balneotherapeutic development is underway at the site.

Figure 2: The main distribution ofhighly mineralized waters in Iceland.

Figure 1: Chloride concentration inIcelandic groundwater (Sigurðsson andEinarsson, 1988).

Figure 4: The main distribution of carbonate waters in Iceland.

S

Figure 3: pH in selected typical low-temperature geothermal waters in Iceland.

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Figure 5: The main distribution ofsulfide waters in Iceland.

Figure 6: The main distribution offluoride waters in Iceland.

Places with low-temperature brines are known especially on the Reykjanes and Snæfellsnes peninsula and in Öxarfjördur NE Iceland (Fig. 2). Near Húsavík (Figs. 2-6) in NE Iceland low-temperature geothermal brine has been used for the treatment of psoriasis. On the Snæfellsnes peninsula the small town Stykkishólmur (Figs. 2-6) utilizes similar low-temperature brine for heating and has been planning the outbuilding of a health resort in cooperation with the local hotel as well as the hospital. The water has been used successfully for the treatment of psoriasis and has been attested by Institut Fresnius in Germany as “Heilwasser” (Sturludóttir pers. comm.). It is claimed to be appropriate for health cures by drinking as well as for bathing therapy for rheumatism. An interesting location within an urban area is the town of Seltjarnarnes (Figs. 2-6), one of the suburbs of the capital city Reykjavík, where ample sources of low-temperature brine of a similar type as the ones in Stykkishólmur and Húsavík are available. There are several places with exessive water and special other attractions, like the Reykhólar field, north of the bay of Breidafjördur (Fig. 2-6) in western Iceland. There the water is fresh, just over 100 °C and available in ample quantities. The largest known sedimentary mud deposits in Iceland are found nearby. There are several tourist attractions in the area, which is also very scenic. In several of the islands in the bay of Breidafjördur south of the area there are springs with hot water of varying salinity. Places with carbon dioxide water and geothermal water available at the same site are not common. The Lýsuhóll field on Snæfellsnes is one of the few known places.

7 Conclusion Prospects to build spas and health resorts in Iceland appear to be very promising. The geothermal waters are of varied chemical composition; there is access to geothermal clay and precipitates as aid in balneotherapy treatment and ample resources of uncontaminated spring water and clean air as well as magnificient scenery and numerous tourist attractions. The local food supplies are fresh and free for contamination and the health system in the country is of high quality. There have been pointed out several places of special interest for further study and market survey. Except for the Hveragerdi and Blue Lagoon Spas and for Stykkishólmur town the kind of balneoteraphy possible for the type of waters and other resources accessible have not been defined yet in any of the places considered promising for outbuilding.

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8 References Agishi, Y., Ohtsuka, Y., Watnabe, I., Yabunaka, N. and Noro, H. (1996). Present features of medical balneology in Japan. Recent progress in medical balneology and climatology. (eds. Agishi and Ohtsuka) Hokkaido University medical library series, 34, 1-10. Ármannnsson, H., Gíslason, G. and Hauksson, T. (1982). Magmatic gases in well fluids aid the mapping of the flow pattern in a geothermal system. Geochim. Cosmochim. Acta, 46, 167-177. Arnórsson, S. (1982). “Carbon dioxide waters in Iceland” (in Icelandic). Eldur í Norðri. (eds. Thorarinsdottir et al.), Sögufélag Íslands, Reykjavík, 401-407. Arnórsson, S. and Barnes, I. (1983). The nature of carbon dioxide waters in Snæfellsnes, Western Iceland. Geothermics, 12, 171-176. Arnórsson, S., Gunnlaugsson, E. and Svavarsson, H. (1983). The chemistry of geothermal waters in Iceland.II. Mineral equilibria and independent variables controlling water compositions. Geochim. Cosmochim. Acta 47, 547-566. Björnsson Ó. G. (2000). Balneotheraphy, medicin and culture. (In Icelandic) Orkustofnun, OS-2000/027, Reykjavík, 108 pp. Björnsson, A., Axelsson, G. and Flóvenz, Ó.G., (1990). “The nature of hot spring systems in Iceland” (in Icelandic), Náttúrufrædingurinn, 60, 15-38. The Blue lagoon Committee (1996). A report to the Ministry of Health (In Icelandic). Reykjavík, 30 pp. Checchi and Company, (1975). Tourism in Iceland. Volume II: Thecnical Reports. Feasibility analyses of specific tourism projects and a tourism developmentprogram for the republic of Iceland. Fresenius W. & Kuβmaul H., 1998. Einführung in die Chemie und Charakteristik der Heilwässer und Peloide. in Deutscher Bäderkalender, Flöttmann Verlag Gütersloh , 45-67. Gunnarsson, Á. (1998). "HNLFI wishes you well and means it", Iceland business, 2, 18. Hauksson, E. and Goddard, J.G. (1992). Radon earthquake precursor studies in Iceland. J. Geophys. Res., 86, 7037-7054. Hotta, A. and Ishiguro, Y. (1986). A guide to Japanese hot springs. Tokyo. Kristmannsdóttir, H. (1990). Types of water used in Icelandic “hitaveitas”. Orkustofnun, Report, OS-91033/JHD-18 pp. Kristmannsdóttir, H. (1992). Geothermal fluids in Iceland. Chemistry and places of special interest for balneological purpose. Orkustofnun, Report, HK-92/08, 10 pp. Kristmannsdóttir, H., Björnsson, Ó.G., Hauksdóttir, S., Tulinius, H. and Hjalmarsson, H. (2000). The utilization of geothermal resources in the tourist industry especially concerning balneology.(In Icelandic). Orkustofnun report, OS-2000/025, 28 pp. Kristmannsdóttir, H., Hauksdóttir, S. and Björnsson, Ó.G. (2001). Balneology-New opportunities in the tourist industry in Iceland (In Icelandic). Orkuþing 2001, (ed. M. J. Gunnarsdóttir) Reykjavík 541-546. Ólafsson, J.H. (1996). The blue lagoon in Iceland and psoriasis. Clinics in Dermatology, 14, 647-651.

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Poliakov, A.I. and Sobornov, O.P. (1975). Uranium, thorium and potassium in volcanic rocks of Iceland. Geochimica, 9. Sigurðsson, F. And Einarsson, K. (1988). Groundwater resources of Iceland. Availability and demand. Jökull, 38, 35-54.

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The effects of developing the geothermal energy in Uniejów town, Poland

Aneta Sapińska-Śliwa Voivodship Fund for Environmental Protection and Water Management in Łódź,

Poland Email: [email protected]

Abstract

There is a growing interest in the use of the geothermal energy in Poland. It is caused by the need of energy sources diversification as well as the necessity to meet the requirements of the European Community. The strategy of EC is based on the increase of the share of energy coming from renewable resources in the general energy balance. The development of the geothermal energy brings a lot of benefits for the heating industry. The report presents the conditions to be met by the geothermal district heating in Uniejów. The aim of the above mentioned analysis was examination of the influence of unconventional heating sources in a town of about 3 000 inhabitants, situated in the central Poland. The town was heated through small, dispersed and traditional boilers using conventional energy sources. The effects are grouped in 3 sections: social issues, ecological issues and economic ones. The results coming from the analysis have an essential impact on planning the future geothermal plants in the Polish Lowland. The advantageous, geological conditions typical of this region are not enough to guarantee the success of geothermal investments. The experience gained from Uniejów ought to be used at the first stage for planning geothermal district heating in such places as Koło, Poddębice, Czarnków, Stargard Szczeciński and others.

Keywords: geothermal utilization, district heating, ecology.

1 Introduction Poland is about to be incorporated in the EU structures; therefore Polish law needs to be adjusted to the EU standards. The most essential of Energy Legal Acts is Energetics Law. There were also other formulated and accepted documents: Policy of Ecology, The Second Policy of Ecology, The Strategy of Development of Renewable Energy and Foundation of Energy Policy upto the year 2002. Solid legal foundations and comprehensible tax policy are a basis for the development of a stable, renewable energy market in Poland. That is also connected with meeting EU obligations. People have been interested in using heat accumulated in geothermal water in Poland for years. At the end of the 1980s the first such projects were attempted (Górecki, 1990). They resulted in making a few boreholes in the Podhale region and in Uniejów in order to substantiate and develop geothermal energy. Three deep geothermal wells were drilled in Uniejów. Due to economic problems connected with political transformation at the beginning of 1990s, further works on two geothermal projects had to be abandoned. The essential research concentrated in the Podhale region because of the convenient geothermal conditions. As a consequence of these works, the Geothermal Research Institute, operating as a division of the Polish Academy of Sciences was founded, the first in Poland. Since that moment geothermal energy for heating purposes has been exploited by three district heating stations in Podhale, Pyrzyce and Mszczonów. An interest in heating plants projects in Uniejów was observed at the turn of the century.

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Thanks to the efforts of Voivodship Fund for Environmental Protection and Water Management in Łódź, the fourth Polish station that runs exploitation of geothermal system was established in 1999. The advantages of using geothermal water for heating purposes are the following:

− reduction of heat production costs, − elimination or significant reduction of air pollution, − decrease of charges connected with pollution emission, − end user independence on price increase of conventional energy sources.

2 Geothermal conditions in Uniejów Resources of geothermal water in the region of Uniejów occur in the lower Cretaceous sandstone at a depth of 2000 m. Temperature of water at the production well head reaches 70°C. Artesian flow rate reaches about 68 m3/h. Water have been classified as sodium chloride, fluoride water, boron water with mineralization of approximately 6.8-8.8 g/dm3 depending on well. It was necessary to rebabilitate injection wells upon investing in geothermal heating systems. This was made at the end of 2000 thanks to the support of the National Fund for Environmental Protection and Water Management in Warsaw. The aim of the reconstruction was to obtain technological and economically advantageous conditions for water injection into the reservoir. As a result, positive parameters of geothermal water injection were obtained, a pressure of 7.1 bar at the flow rate corresponding to the self outlet productivity. The exploitation of geothermal water for heating purposes circulates in a closed cycle. Geothermal water is produced from the well Uniejów PIG/AGH-2 and after going through heat exchanges and transferring heat to heat carrier, it is directed to the same water-bearing layer through the injection well Uniejów PIG/AGH-1. The hydraulic contact in the deposit was confirmed by hydrogeologic tests carried out in winter 2000/2001. At present, chilling water is injected into the injection well Uniejów PIG/AGH-1 at the appropriate economical and pressure parameters of injection. However, taking into account the chemical composition of brine as well as the planned growth in the use of Uniejów geothermal water for the needs of balneotherapy sanatorium, the third borehole should be considered as an additional injection well, e.g. well Uniejów IG-1. Its location is advantageous and due to a relatively small distance from the present well injection site. There were also conducted researches on geothermal water for therapeutic purposes. They proved to have a beneficial influence on health. Besides, they can be used for recreation and balneotherapy purposes. The geothermal water in Uniejów is recommended for curing the following illnesses:

− rheumatic illnesses, − orthopedist and traumatic illnesses, − nerve system (neuralgia, neurosis), − illnesses of vessels of lower limps.

The research study contributed to starting water therapy and making Uniejów a spa center. This is especially important as no health resorts can be found in that region of Poland. These plans may succeed not only because of the Uniejów's location (in the Warta river valley) but also because of geothermal heating systems and clean air.

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3 Development of geothermal energy Works on the geothermal system heating started at the beginning of 2000 and lasted to the end of 2001. In the framework of the geothermal investment, ten kilometers long heating pipelines have been lied out and addition installments have been made. Geothermal district heating extends from public buildings, e.g. school, teacher's house, kindergarten, church, presbytery, health center, chemists, block of flats and two detached house estates. About 170 new customers were linked to the system. A heating central using geothermal water energy of 3.2 MW was constructed, and heating plant and oil boilers of 2.4 MW were installed as a peak-load heating source. The geothermal energy coming from water is presently used for central heating and heating of tap water. Tap water that is used for private and public residential buildings is produced in the heating plants. The maximum production of tap water is determined by total heating power of heat exchangers. It reaches up to 0.4 MW (Sapińska, 2000). The percentage share of thermal energy production for the individual heating sources in the period of October 2001 to September 2002 is shown in the Figure 1.

0%20%40%60%80%

100%

Oct

ober

Nov

embe

r

Dec

embe

r

Janu

ary

Febr

uary

Mar

ch

Apr

il

May

June

July

Aug

ust

Sept

embe

r

geothermal energyconventional energy

Figure 1: The percentage share of heating energy production in the period of October 2001-September 2002.

Plans are made to use the chilling geothermal water for recreation and balneotherapy purposes. It will be directly used for bathing in small swimming pools with brine. In the open and covered swimming pools, low temperature heating waste included in the water leaving heat exchangers in the geothermal heating plant is utilized for bathing purposes. Cascaded receipt of heat as the most advantageous way of development of geothermal water enables a better use of heat and improvement of economic efficiency of the investment. At present, there is a need to look for an investor who would be able to build an injection well on the ground belonging to the Geothermal Company. An aquapark is planned there. There are arguments for a recreation center in Uniejów with its geothermal waters, i.e. a short distance to the urban area of Łódź (over 800 000 of inhabitants) and clean environment.

3.1 Economic effects The geothermal heating plant in Uniejów supplied heat to 104 buildings during the period of 01/10/2001 until 30/09/2002. There were 15 institutions and 75 individual recipients among the 90 heat recipients. The heating plant has sold almost 20.000 GJ heating energy and about 2 650 m3 of hot tap water.

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During the heating season 2002/2003, about 64 buildings will be heated by geothermal energy. In comparison with the last season, the number of individual recipients dropped down. That was connected with the change of heat charging systems in accordance with the rates set by Energetic Control Office. It follows from the Energetics Law of 01/10/02 that there were introduced charges for the actual consumed heat and also regular payments for ordering heat power, transferring the energy, and addition to the heating system. In spite of the dropping number of heat recipients, the heat sale seems to increase. Geothermal Company gained two new customers, therefore sale indexes increased. Figure 2 presents the structure of incomes of energetic plant. The increase of incomes obtained from regular costs of heat supplies increases the reliability of incomes forecasts. At the same time it has a negative impact on the decisions of individual customers. The increase of constant heat price causes that the cost of energy for individual recipients depends to a smaller degree on real consumption of heating. It may tempting to look for other energy sources, the cost of which will depend solely on the quantity of consumed energy. The right rates always should be an element of economic calculation but on the other hand the psychological aspect is also important. The monopolistic heat energy supplies are a specific of Uniejów. However, that monopoly is limited; most of the recipients have had the possibility to use individual coal heating.

12%

84%

4% 19%4%1%

71%

5%

a) b)

variable charge for consumed heat Invariable charge for yearly energy

transfer

variable charge for hot tap water invariable charge for yearly ordered heating power

standing charges for links for heating chain

Figure 2: The structure of incomes of energetic plant. a) during heating season 2001/02, b) during heating season 2002/03 (forecast).

Polish heating company used to charge separately for heat and warm tap water, because they use separate pipe systems for both purposes. Unfortunately, the income coming from the sale of heat and warm tap water did not cover the operating costs of the Company, inevitably leading to losses in the first season of its activity. Even with a loan granted to the Company, it will not be easy to generate net profit very quickly. Total costs consist of the costs of repairs and conservation of the installation. Their share increases with the growing salinity of geothermal water. The salinity of geothermal water necessitates frequent cleaning of heat exchangers, shortens the life of the pipelines and casing. Therefore, it is necessary to increase heat sales. There is an essential technical reserve. It seems sensible to use the heating in agriculture (Dziubiński and Sapińska, 1999). The big potential is connected with the recreation center where the low

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temperature geothermal water (before the injection) can be used. As a big recipient of waste heat, the acquapark can get preferential energy price. The idea seems to be much more reasonable as there is no such a recreation center. The next possibility for improving the economical aspect of the investment is balneology services. The Geothermal Company Uniejów has started its activity in this field in September 2002. It gained considerable profits during the first three months. The development of operation base, as well as the rehabilitation and health care based on balneology could have a profitable influence on the investment in Uniejów.

3.2 Ecological effects Before setup of the geothermal heating chain, the town of Uniejów did not have a centralized heating system. The heat was supplied from a few small boiler houses. Most of detached houses were heated using individual heat coming from stoves for charcoal or coal dust. The annual coal consumption in 10 local boiler houses and 160 stoves in detached houses amounted to about 3 000 tons. Most of all generation stoves in the public buildings were over-measured. They were low efficiency stoves from 45 to 67%. The average temperature of supply and return in the central heating installation in the heating season was about 75/70oC. None of the considered boiler houses was equipped with dust-filter appliances. Building of geothermal heating plant contributed to the decreasing amount of dusts and pollutions emitted to the atmosphere in Uniejów. After activating the geothermal center, the main emission come from burning fuel oil in the peak boiler house, operating during cold weather outside. The ecological effect will be in proportion with the number of recipients who will be using the geothermal heat during the season. The quantity of emission to the atmosphere before and after activation of the heating plant in Uniejów may be found in the Table 1. Reference is made to the number of replaced traditional boiler houses and heat sold during the year.

Table 1: The quantity of emission to the atmosphere before and after replacing traditional coal boiler houses with the geothermal heating plant in Uniejów.

The element of emission CO2 SO2 NOx CO Dust BenzapirenUnit Mg/year kg/year

The distracting coal boiler houses 5500 38240 3000 300000 135000 60 The centralized heating system based on

geothermal heating plant with peak energy source 180 135 500 50 275 1

3.3 Social effects Uniejów is a small town with about 3000 inhabitants situated in the central Poland. It is located nearby Łódź (800 000 of inhabitants), Poddębice and Koło – potential geothermal energy users. The analysis of social phenomena in Uniejów may contribute to the acceptance of a more advantageous policy in towns where geothermal plants will be built. This is the first geothermal plant in Poland in a small urban area. Only 30% of all Uniejów’s inhabitants leave in the blocks of flats. The rest of the buildings are detached houses. A significant number of heating recipients are individual ones. This causes that the investment costs of making a geothermal plant will increase. The company makes efforts to gain every individual recipient because of the excess of power in the heating plant. The individual recipients are very demanding.

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It is expected that the development of balneotherapy and building of the acquapark should increase the attractiveness of the town for tourists to the benefit of the inhabitants. It follows from the analysis of geothermal investments in other towns, that social aspect must be taken into account along with geological, technical and economical analyses. Social aspects should be taken into consideration in the project. A program should be created to help prepare people to such an investment.

4 Conclusions • The Geotermia Uniejów Ltd. is the first heating plant that supplies energy to the

recipients in a small town. The experience gained at the investment and exploitation stages should be properly used. This is connected with additional costs resulting form the innovation character of such investments in the Polish conditions.

• The condition of effective consumption of geothermal heat is taking away the biggest quantity of energy from geothermal water. The project should point to the cascaded use of heat. Therefore, at the beginning of the project one should consider using energy for heating buildings than for other purposes required lower temperatures like balneotherapy, swimming pools, glass houses or acquaparks (that are still not very popular now.)

• To make efficient investments means to carefully analyze the market for the energy gained from geothermal heating systems. The starting point for any further analyses should concentrate on the technical availability of geological energy sources. Among its more important elements are sociological and marketing issues.

• Because of their localization, big cities are more advantageous for geological investments. A significant majority of recipients could be public and group recipients. In order to work out a reliable study of real profits coming from the heat sale, only public and individual recipients who declared their wish to be connected to a new chain should be analyzed at the beginning of preparing the project.

• The ecological aspect is very important in small towns, where geothermal energy covers a considerable percentage of heat demand in the whole town. Unfortunately, the benefits resulting from the reduction of pollution emission cannot be included in the economical calculation of investment.

Acknowledgements The author thanks the Board of management of Geotermia Uniejów Ltd. for access to material and documentation and also the Polgeol Company for precious remarks in reference to the paper.

5 References Dziubiński, M. and Sapińska, A. (1999). Preliminary concept of using geothermal energy in greenhouses in Skierniewice. Exploration Technology, Geosynoptics and Geothermal Energy Vol. 6/99 (in polish), 37-44. Energy Law. (1997). Regulation of 10 April 1997, Official Journal No. 54, item 348. Górecki,W. (1990). A project of the Utilization of the Lower Cretaceous Geothermal Waters in the Mogilno-Łódź Synclinorium with the Special Regard to the Uniejów

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Region. Report: Conference “Possibilities of the Utilization of Geothermal Waters in Poland with Special Regard to the Mogilno-Łódź Synclinorium”, University of Mining and Metallurgy Publishing, Cracow (in polish). 14 pp. Sapińska, A. (2000). The state of works on a developmenet of the geothermal plant in Uniejów, Report: International Seminar „Role of Geothermal Energy in Sustained Development of Mazowsze and Łódź Regions”, Minerals and Energy Economy Research Centre of the Polish Academy of Sciences Publishing, Symposia and Conferences, Vol. 45, Cracow (in Polish). 12 pp.

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Meeting the annual heat demand Þorleikur Jóhannesson M.Sc. mech. eng. and Þrándur S. Ólafsson M.Sc.

Fjarhitun hf. Borgartún 17, 105 Reykjavík, Iceland Email: [email protected], [email protected]

Abstract

The paper describes a study of the optimum utilization of a low temperature geothermal field in one of the larger cities in China. The main task is to meet the annual space heating demand by seeking the combination of geothermal energy (low running costs) and conventional boilers and/or heat pumps (low investment cost) that result in the overall lowest energy cost. Different combinations of heat sources are compared for different sizes of areas are considered. The solutions for different sizes vary and play a main role in finding a strategy to meet the heat demand. The environmental aspects of the district heating system are considered as well. Finally the energy price to the consumer is calculated for the project’s amortization time of 10 and 25 years respectively.

Keywords: geothermal utilization, heat pumps, boilers, district heating, emissions.

1 Introduction The task of how to utilize a low temperature geothermal field is a practical one. In its most general form, the goal is to find a solution where as few wells as possible need to be used. The demand of power for space heating is unfortunately not uniform and there is a peak demand during the coldest days. To meet the demand a trade-off has to be considered to combine geothermal energy (low running costs) and conventional boilers (low investment cost) for the lowest overall energy cost. Not only must the project be evaluated on an economic basis, the environmental aspect also plays an important role and should be given due consideration.

2 Load curve The district-heating load depends strictly upon two factors: weather conditions and thermal insulation of the buildings in question. The weather conditions encountered are continental, i.e. cold winters and hot summers. The insulation (resistance to cold during cold days and vice versa) is estimated to be R = 0,93 (m2K)/W (or k = 1,08 W/ m2K). An average apartment is 65 m2 inhabited by roughly 3 persons. The total load for an area of 400.000m2 of housing, during an average year is 65 GWh. Of those, 46 GWh are used for space heating, while the remaining 19 GWh are used for heating of domestic hot water. Figure 1 depicts the average load duration curves for the appropriate buildings in the area. Curves are set forth assuming 3 different values of total floor space to be heated. The geothermal field in question has been explored during recent years. Its production potential has been estimated from wells already drilled. Based on a pre-feasibility analysis of the wells, the estimated annual average flow from each well is 20 l/s of 70°C water and the maximum flow 35 l/s. All additional wells in the field are expected to posess the same capacity. In their article the authors discuss the different approaches of meeting the heat demand, for a short period, when these constraints are relaxed. Figure 1 indicates the geothermal usage of two 35 l/s production wells and one reinjection well for three given values of heated floor space.

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0

10

20

30

40

50

60

0 50 100 150 200 250 300 350 400Days cumulated

Pow

er (M

W)

Total load-400.000m2 Geothermal-400.000m2Total load-800.000m2 Geothermal-800.000 m2Total load-1.000.000m2 Geothermal-1.000.000m2

22,2 MW

2,2 MW

55,5 MW

Geothermal

Alternative peak powerAnnual average flow:400.000m 2 : 32,4 l/s800.000m 2 : 43,0 l/s1.000.000m 2 : 47,1 l/s

Figure 1: The load duration curves in the cases of 400.000 m2, 800.000 m2 and 1.000.000 m2 floor space. The utilization of geothermal water is shown as well.

As can be seen in Figure 1 the utilization of the geothermal energy increases with the size of the total floor space. The smallest area considered consists of 400.000 m2 of floor space, and at maximum demand times, the peak power demand is 11 MW. The utilization of geothermal water and the peak power demand increases, as the total floor space increases. In the case of a total floor space area of 1.000.000 m2 the maximum demand for peak power is 44,2 MW. Figure 1 also shows that when the peak geothermal utilization of the water is reached (around the 150th and 75th day on the chart for 800.000 m2 and 400.000 m2 of floor space respectively) the lines representing geothermal utilization at higher loads are not fully parallel. This occurs since the return temperature from heating systems at different relative loads is not constant. The annual flow of geothermal water exceeds the permissible limits for two production wells (2 x 20 l/s) for the larger areas, i.e. for 800.000 m2 and beyond. Thus, when the total floor space is larger than 400.000 m2, three or more production wells are needed to meet the demand, or the use of alternative peak power sources.

3 Alternative peak power sources Alternative peak power sources evaluated are boilers and heat pumps. Boilers can be driven with various kinds of fossil fuels or natural gas while the heat pumps can be driven with electricity or heat (compressor or absorption heat pumps). For this study the potential peak power sources considered are a natural gas boiler and an absorption type heat pump, driven by a natural gas boiler station.

4 The price of energy The price of energy differs greatly between geothermal energy sources and their alternatives. The costs influencing the energy price are the initial investment costs of the district heating system and the system’s operational costs. Investment cost consists of all equipment and its installation, and any related work (e.g. drilling of wells) but does not take into account costs related to exploitation rights. Operational cost

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consists of basic operational costs (such as maintenance) and fuel costs (fossil fuels or electricity). Table 1 shows a comparison of typical investment costs per produced MW, as well as operational costs per GWh. Investment costs and operating costs set forth in Table 1 do not include costs related to distribution systems nor house connections.

Table 1: Typical basic investment cost and operational cost for different sources of energy.

Initial cost / MW Running cost / GWhGeothermal US$450.000 US$50 Boiler US$40.000 US$30.000 Heat pump US$240.000 US$18.000

Table 1 is only instructive for a geothermal system in this particular geothermal area. With total floor space of housing amounting to 400.000 m2, the district heating demand can be met by using various energy sources in combination. The following table summarizes the associated costs, investment and operational, now including costs associated with distribution systems and house connections for each of the options. It also shows an estimate of the emitted CO2. All values are set forth for weather conditions encountered over an average year.

Table 2: The investment and operating costs in thou. US$, for various ways of meeting the annual heat demand and their respective CO2 emissions in tons. The total floor space of housing is 400.000 m2.

Power sources Investment

costs

Annual average fuel

costs

Annual operational

costs

Total annual operational

costs

Annual average CO2

emissions 22,2 MW boiler only 3.610 1.980 91 2.071 14.022 System 2-1 + 11 MW boiler 10.530 181 263 444 1.368 System 2-1 + 10,5 MW heat pump 12.570 107 314 421 805 System 3-2 + 5 MW boiler 13.980 20 350 370 163 System 4-2 15.230 1 381 382 17 A general assumption would be to assume that the lifetime of the power plant is finite. When the power plant is shut down the wells and boilers are assumed to be worthless, for the sake of simplicity. Under these conditions, a known formula can be used to calculate the accumulated present value of the project. This formula is as follows:

N

N

n

N

n PVAIr

rAIr

AIPV *111

*)1(

1*1

+=

⎟⎟⎟⎟⎟

⎠

⎞

⎜⎜⎜⎜⎜

⎝

⎛⎟⎠⎞

⎜⎝⎛

+−

+=+

+= ∑=

, for finite N’s (1)

where: PV: present value, I: Total investment cost,

A: Total annual operational costs, N: number of years, r: interest rate.

Using formula (1) and the values provided in Table 2, the present value (cost) of the district heating system’s life cycle cost can be calculated as a function of the system

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lifetime. Figure 3 shows the results, for a total floor space of heating of 400.000 m2. In Figure 3, sys 2-1 means 2 production wells and 1 reinjection well, sys 3-1 means 3 production wells and 1 reinjection well and so on. In Figure 3, the interest rate is assumed constant at 6% per annum.

10.000

15.000

20.000

25.000

30.000

35.000

40.000

0 5 10 15 20 25 30 35 40Years

Acc

umul

ated

PV

in 1

03 $’

s

Sys 2-1 + 32 MW boiler Sys 3-2 + 26 MW boilerSys 4-2+20,5 MW boiler Sys 4-2 10,5 MW hp.+ 10 MW boilerSys 5-2 + 10,5 MW hp + 4,5 MW boiler Sys 5-2 + 15 MW boilerSys 6-3 + 9,3 MW boiler 44,4 MW boiler only

Figure 3: The present value (cost) of the district heating system’s life cycle cost as a function of system life. Total heated floor space is 400.000 m2.

As seen in Figure 3 the most economical way to heat the 400.000 m2 of floor space is to use system 2-1 and an 11 MW boiler, unless the system is intended to operate for 3 years or less. When the total floor space is 800.000 m2, many other different combinations of heat sources can be put forth. These combinations are listed in Table 3.

Table 3. The investment and operating costs in thous. $ for different ways of meeting the annual heat demand and their respective CO2 emissions in tons. Total floor space is 800.000 m2.

Power sources Investment

costs

Annual average fuel

costs

Annual operational

costs

Total annual operational

costs

Annual average CO2

emissions 44,4 MW boiler only 4.590 3.960 115 4.075 28.044 System 2-1 + 32 MW boiler 12.660 1.487 317 1.804 11.224 System 3-2 + 26 MW boiler 16.010 929 400 1.329 7.501 System 4-2 + 20,5 MW boiler 17.610 469 440 909 3.569 System 4-2 + 10,5 MW heat pump + 10 MW boiler 19.690 300 492 792 2.297 System 5-2 + 15 MW boiler 21.270 224 532 756 2.081 System 5-2 + 10,5 MW heat pump + 4,5 MW boiler 19.210 159 480 639 1.596 System 6-3 + 9,3 MW boiler 22.530 597 563 1.161 233

As indicated in Table 3 the solutions for a total floor space of 800.000 m2 are not mere duplications of the solutions for a total floor space of 400.000 m2. For instance,

2the sys 2-1 and a 11 MW boiler solution, for 400.000 m , are not duplicated but has

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changed to sys 4-2 and a 20,5 MW boiler, since the tap water load does not double as the area doubles. The resulting present value of the district heating life cycle cost is considered

igure 4: The present value of the district heating life cycle cost as a function of system

The graph indicates that all attractive long-term solutions involve at least 4 production

5 Environmental aspects 2 for all options have been set forth in Table 2

he

for 800.000 m2 in Figure 4. Figure 4 compares the different options over time, and by doing so, it gives an overview of the most economical combination of power sources.

22.500

5.000

7.500

10.000

12.500

15.000

17.500

20.000

0 5 10 15 20 25 30 35 40Years

Acc

umul

ated

PV

in 1

03 $’s

Sys 3-2 + 5 MW boiler Sys 4-2 Sys 2-1 + 11 MW boilerSys 2-1 + 10,5 MW hp. 22,2 MW boiler

Flife. Total heated floor space 800.000 m2. The result for a 44,4 MW boiler is only shown partially.

wells. One way to utilize the geothermal field would be to have a cautious preliminary drilling schedule, since the solutions differ very slightly. When four production wells and two reinjection wells have successfully been drilled, a decision could be made whether to add one more production well. This decision should above all be based on experience regarding the previous 6 wells (4-2). If, the total area of housing is expanded further than 800.000 m2, towards a total floor space of 1.000.000 m2 or even higher, additional wells seem to become more feasible than other alternative options, based on these two scenes. In such a case, a geothermal utilization time-schedule has to be laid out to simultaneously meet all needs of the area.

The estimated annual emissions of COand Table 3. Air pollution is a serious problem in some areas of China, partially since large amounts of H2S, SO2, NOx and CO2 are emitted when the predominant energy source, coal, is burned in power plants. For this reason it might be feasible to select the more expensive solutions since they reduce overall pollution to a larger degree. The Global Environment Fund (GEF), and other global funds such as tPrototype Carbon Fund (PCF), have provided grants to various geothermal projects, similar to this one. The policy of these funds is to grant a specific amount for each ton of CO2 not released to the environment, compared with traditional methods. Here an initial grant of $4/ton CO2 over a period of 25 years (discounted at r=3,60%) will be considered for comparative purposes only. This amount has been granted from GEF, and similar institutions, in geothermal projects e.g. in East-Europe and is in line with environmental policies as of today. The expected amount of the grant for the various

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combinations of heat sources is shown in Table 4. If an environmental grant, as indicated in Table 4, is taken into account and added to the analysis of the district heating system, the order of feasibility does not change in the first phase of the project (400.000 m2) and the changes for the second phase (800.000 m2) are small (<5%).

Table 4. Expected environmental grants in $ for the various combinations.

Ar -2+hp. Sys 6-3+boil.ea (m2) Sys 2-1+boil. Sys 2-1+hp. Sys 3-2+boil. Sys 4-2+boil. Sys 4-2+hp. Sys 5-2+boil. Sys 5400.000 825.000 862.000 904.000 913.000 - - - - 800.000 1 1.679.000 1.693.000 1.725.000 1.814.000 .097.000 - 1.369.000 1.596.000

6 Price to the consumer as been evaluated (Figure 3 and Figure 4), a price

Table 5: The prices for the project to pay off in 10 and 25 years.

The price to pay off in 10 years Price to pay off in 25 years

When the total cost of the energy hto the consumer can be calculated. The following table indicates the minimum price that each customer should be charged for the different combinations in order to break even. Table 5 assumes that all users pay for their energy usage, at the right time.

Power source Area

US$/m Yuan/m(m2) US$/

2 2kWh Yuan/m2

w. grantUS

US$/m Yuan/m$/

2 2kWh Yuan/m2

w. grant22,2MW gas boiler 400.000 0,044 6,71 55,0 55,0 0,040 6,19 50,8 50,8 System 2-1 + 11 MW boiler 400.000 0,030 4,60 37,8 35,5 0,020 3,15 25,8 24,5 System 2-1 + 10,5 MW heat pump 400.000 0,034 5,24 43,0 40,6 0,023 3,49 28,6 27,2 System 3-2 + 5 MW boiler 400.000 0,037 5,73 47,0 44,5 0,024 3,71 30,5 29,0 System 4-2 400.000 0,039 6,06 49,7 47,1 0,025 3,92 32,1 30,6 44,4 MW boiler 800.000 0,040 6,18 50,7 50,7 0,038 5,85 48,0 48,0 System 2-1 + 32 MW boiler 800.000 0,028 4,23 34,7 33,2 0,022 3,45 28,3 27,4 System 3-2 + 26 MW boiler 800.000 0,029 4,48 36,7 34,8 0,022 3,33 27,3 26,2 System 4-2 + 20,5 MW boiler 800.000 0,027 4,20 34,4 33,7 0,019 2,93 24,0 23,1 System 4-2 + 10,5 MW heat pump + 10,5 MW boiler 800.000 0,029 4,39 36,0 33,7 0,019 2,98 24,4 23,1 System 5-2 + 15 MW boiler 800.000 0,028 4,26 35,0 32,6 0,019 2,88 23,6 22,3 System 5-2 + 10,5 MW heat pump + 4 MW boiler 800.000 0,029 4,47 36,6 34,2 0,019 2,93 24,0 22,7 System 6-3 + 9,3 MW boiler 800.000 0,029 4,53 37,2 34,6 0,019 2,95 24,2 22,7

As indicated in Table 5, an environmental grant does not influence the price to

7 Conclusions Different approaches of meeting the annual heat demand exist. The comparison between different selections discussed in this report can be of assistance in a final selection for housing areas of 400.000m2 and 800.000m2 in specific parts of China.

consumer greatly. Values in Table 5 assume a zero residual value of all system components. In actuality this residual value is higher since the distribution system, boilers and heat pumps etc. can be sold as second hand equipment when operations cease. The consumer price should thus be somewhat lower (3-10%), depending on the system’s age upon closure. For some areas in China, a comparison with a pure boiler would be the most logical one, but in this case it is assumed that the use of pure boilers have already been permitted.

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Estimated geothermal analysis and the accur

flows used in this analysis are based on a pre-feasibility acy of the posted results depends on the exactness of results

s, Pergamon Press, Oxford. 558 pp.

Holman, J.P. (1997). Heat transfer, 8th ed. McGraw-Hill, Inc, New York. 696 pp. n and Þrándur Ólafsson. (2003) Estimating short-term capacities

from that analysis. If the results from the pre-feasibility analysis turn out to be typical for geothermal wells in the area, this analysis may turn out to be useful in meeting the annual heat demand in the area.

Acknowledgements The authors thank Dr. Oddur B. Björnsson at Fjarhitun hf. for his advice, suggestions and help in completing the study.

8 References Harrison, R., Mortimer and N.D., Smarason, O.B. (1990). Geothermal heating, ahandbook of engineering economic

Þorleikur Jóhannessoof geothermal wells, IGC 2003, Reykjavík.

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District heating for holiday homes Jakob S. Friðriksson

Mechanical Engineer M.Sc., Reykjavik Energy, Iceland E-mail: [email protected]

Abstract

Reykjavík Energy is constantly pursuing new market opportunities for energy products. One recent project was the development of a district heating service in an area mainly consisting of holiday homes in Grímsnes, 60 km east of Reykjavík. District heating systems for holiday homes change dramatically the utilisation period, enabling the owners to use it all year round despite of the harsh Icelandic climate. Tackling this project required different approach than in densely populated areas, both technically and from a marketing perspective. The following article will describe the concepts of heating holiday homes using district heating, challenges that were met on the way, solutions to problems and a summary of the project.

Keywords: district heating, holiday homes, new products, sparsely populated areas.

1 New markets for district heating In Iceland most of the traditional market for district heating services has been covered. Most of the city’s, towns and villages that are close to geothermal energy utilise it for space heating. Reykjavík Energy however has taken the initiative and began looking at different market areas for district heating, namely holiday homes, normally located in the countryside. The demand for district heating in holiday home areas has caught us at Reykjavik Energy by a surprise. District heating is a commodity celebrated by many holiday homeowners. The purpose of this paper is to describe projects in this market area hoping it may challenge others to start looking for new ways to utilise geothermal energy and work towards increasing the utilisation of geothermal energy in the energy markets.

2 The concept of holiday homes It is becoming more and more popular in Iceland to have access to holiday homes, either by owning or renting short term. There is a strong desire for many urban residents to retrieve from the rat race into the tranquillity of the countryside to relax and find comfort at a unique location chosen or developed by you. Those who can, spend a lot of their time and effort in their holiday homes, building, maintaining, gardening and/or relaxing. Holiday home areas are usually built on small section 5 to 10 thousand square meters, normally built in clusters where services such as roading, waterworks and electricity are accessible. The holiday home gives shelter from the harsh and rather unpredictable Icelandic climate. Typically the main occupancy is during the summer time. But summer time in Iceland is quite different from the typical European summer climate, all sorts of weather can be expected. As can be seen from the weather data shown in Figure 1 the heating season lasts the whole year for holiday homes, or at least during its occupancy.

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2.1 Holiday homes Holiday homes can be categorised into two basis categories, privately owned and public usage (in some cases limited e.g. to union members).

Average temperature in Reykjavik

-2

0

2

4

6

8

10

12

jan feb mar apr mai jun jul agu sep oct nov des

Month

Temperature [°C]

Figure 1: Monthly avarage tempertures in Reykjavík, Iceland.

2.1.1 Public holiday homes The demand for public holiday homes is normally huge during the summer season. Every week is booked months in advance. For several reasons this time of peak demand is getting shorter, e.g. shorter school holidays and more concentrated vacation periods. Outside the peak periods most of the houses are vacant. This has put some strain on the owners; increased utilisation of the homes is essential for the financial well being.

2.1.2 Private holiday homes The ownes and the closest family and friends generally use private holiday house. The occupancy is normally more distributed and less frequent than for public holiday homes. Still the demand for comfort is increasing; attraction is needed for the children and grandchildren to come for a visit.

2.1.3 Increased utilisation Holiday houses are normally far from being some kind of bungalows, the investment is considerable and normally the holiday homes are quality houses. And the comfort shouldn’t be less than at home e.g. demand for similar appliances as at home. Most holiday homes have some space heating appliances, electricity, gas or district heating which is getting more and more common. Considering the investment people and organisations have made in their holiday homes it does not come as a surprise that the majority of the owners wants to increase the utilisation period of the houses. The houses must be inhabitable despite the climate and fully equipped with all modern appliances to provide the comfort and leisure. The best way to increase the utilisation is to plug the holiday homes into a district heating system. Heat the houses all year round and the possibility to install a spa (Icelandic: “heitur pottur”), which has a huge attraction for all generations. Holiday homes with access to district heating service and equipped with a spa pools

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have higher utilisation than those without. Owners of public holiday homes are experiencing a boycott of those homes without spa pools. Similar applies to new holiday home areas, those with access to district heating service are much more popular.

3 Feasibility The market for district heating in holiday home areas is definitely there. But there are of course few conditions that have to be met before the district heating service can be built. Necessary prerequisites are:

1. Geothermal energy 2. Market 3. Feasibility

3.1 Geothermal energy Geothermal resources can be found in quite a few places in Iceland. Most of the geothermal energy located close to traditional market e.g. towns and villages have already been harnessed for district heating. Many holiday home areas are located in the vicinity of geothermal resources that can easily be harnessed. Other energy sources for the district heating such as electricity and oil are too expensive.

3.2 Market Holiday home areas that are potential for district heating project have to be densely populated. The number of holiday homes must also be considerable. Those parameters are however case sensitive, based on the investment in each project.

3.3 Feasibility Project must be planned ahead and its profitability must be determined. Availability of the geothermal energy, harnessing costs, transportation and distribution must be planned and estimated. The income will then determine the feasibility with acceptable rate of return for the investment. Reykjavík Energy uses methods of cash flow analysis to determine wether projects are feasible or not.

4 Grímsnes district heating service The first project on district heating for holiday homes, Reykjavík Energy initiated was in Grímsnes. Grímsnes is located 60 km east of Reykjavík and is located between the rivers Sogið and Hvítá.

4.1 Grímsnes holiday home area Over 1500 holiday homes have been built in Grímsnes. It was estimated feasible to build a district heating in a part of the area, which covers approximately 750 holiday homes. This area is the most populated and concentrated making it the most feasible. It is not fully built yet; the estimated number of sections is well over 1000. Our expectations are that most of the un-built sections will be occupied within ten years. The number of holiday homes in the neighbourhood is constantly growing. The demand for sections is huge in this area. This gives us good hope for the future, extending the district heating in Grímsnes even further now that we have the basic structure ready.

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4.2 The district heating service The district heating service in Grimsnes was commissioned in December 2002, after approximately one year of construction and additional year for planning and design.

4.2.1 The geothermal resource The geothermal field is located very close to the market. Three production boreholes have been drilled and the capacity of the most successful bore is 60-70 litres per second of 84°C water. The chemistry of the water allows it to be distributed directly to our consumers and it can be used for washing and bathing. The full capacity of the field is unknown but the above-mentioned boreholes can supply a total of 1200 holiday homes with sufficient hot water.

4.2.2 The distribution system The main supply pipe running through the area is of pre-insulated (Poly-Urethane) steel, dimensions DN 200, 150 and 100. For all dimension below DN 100 and throughout distribution network we used pre-insulated PEX (poly-ethylen-crossbound). The distribution network is of course a one-pipe system no return pipes being necessary. The return water is discharged into the lava. The flexibility of the PEX pipes has an advantage over the rigid steel pipes. This has been especially helpful when tracing paths, bypassing trees or other structures inside the sections. The supply temperature measured at the holiday homes ranges from 55° to 80°C, depending on the distrance from the geothermal field and the number of connected holiday homes in the vicinity. The supply pressure varies from 2 to 6 bar.

4.2.3 The delivery and sales Reykjavík Energy connects the supply pipe to each customer in a cabinet normally located on the exterior of the holiday home. The customer connects his heating systems into the cabinet as well. By using the cabinet as a connection point Reykjavík Energy can have access to the connection at all times, doesn’t matter whether the holiday home is occupied or not. Reykjavík Energy supplies bypass valve, filter and flow restriction into each of the cabinets. The customer supplies all other equipment necessary. The energy tariffs are simple, the customer subscribes to a certain flow and the flow determines his annual tariff. The flow restriction in the cabinet is adjusted to the subscribed flow. Minimum subscribed flow is 3 litres per minute, which is in most cases sufficient for heating a normally sized holiday home. The customers can add to the minimum flow according to their needs. Many customers with spa pools have subscribed to additional one or two litres per minute.

Table 1: District heating tariffs in Grímsnes.

Item Cost [kr] Cost [$] Cost [€] Annual fee: -Min. flow 3 litres per minute

47,364

592

526

-Additional 1 litres per minute 9,848 123 109 Connection fees

104,415

1,305

1,160

Selling energy by restricting the flow does seem awkward at first, especially when energy savings are considered. The sale does not encourage the customer to

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save energy, but it encourages the utilisation of the peak flow to its fullest. Critics have claimed it would have been better to install meters at each holiday home and sell the energy by cubic meters. The tariff structure was determined bearing two things in mind:

• The structure may not encourage customers to turn down the heating of the holiday homes during periods of non-occupancy, which normally are during winter periods. This would affect the neighbouring customers, decreasing the flow in the distribution system and increase the risk of frost damages in the system.

• With flow restriction at each holiday home it is easier to determine the simultaneous flow and therewith dimensions of the distribution network. In fact this means smaller diameters and less investment in the system as a whole.

4.2.4 Marketing The most challenging task in this project is marketing part. It was impossible to predict the participation of holiday homeowners and their rate of connection to the district heating. In towns were district heating had been built most of the potential customers hooked up within a year from its commissioning. It was, in most cases, far cheaper to use geothermal district heating service than electricity or oil. The encouragement to connect holiday homes to district heating is not only about money; it is about increasing the comfort levels and it enables extended utilisation of the holiday homes all year round. The risks of the projects in regards to the marketing were identified and challenged by a team at Reykjavík Energy. Most of the foreseeable problems were solved before the construction began:

• Press releases, direct mail and meeting with the association of holiday homeowner in the areas were used to inform people about the plan to build a district heating service, get responces and discussion on the project.

• Reykjavík Energy prepared guidelines on how to connect to the district heating system and recommendations on how holiday homeowners should plan their heating systems. Simple things such for instance having a closed circuit heating system through a heat exchanger with anti-frost fluid circuling in the house, minimizing the risk of leaks in case of frost damages.

• Rule number one during construction, never go into a section without consulting the owner on where and how to lay the supply pipe. By doing it this way the damage was minimised to the vegetation and structures. By consolidating the owner he was partly responsible. Before the project started we expected to get a lot of claims regarding this issue, but until today there has been relatively few.

• Tariffs are kept at a minimum to get as much participation as possible. Tariffs are very low when compared to similar district heating services. This required a cost focused project, where each part was tendered out to contractors, to keep the cost at a minimum.

• Extended services were offered to those interested. Reykjavík Energy offered to design and build the heating system for the holiday home owners. The interest caught us by surprise, almost 10% of applicants have used this service.

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4.2.5 Achievements The participation in Grímsnes district heating has been very good, beyond our original estimates. Of 750 holiday homes, 500 have applied for connection to the district heating and 350 have already been connected to the district heating service. This achievement is considerable taking into account the fact the district heating was commissioned in December 2002. The priority over the next two years will be to increase the number of participants, getting to those 250 holiday homes that have not participated and keeping a close eye on the neigbouring holiday home areas with possible extention of the district heating in mind.

5 Other projects based on the Grimsnes model

5.1 Munaðarnes Next year Reykjavík Energy will begin construction on a new DH service in a holiday home area approximately 100 km north of Reykjavík. 160 holiday homes are in the area, about 90 of them are publicly owned that is owned by a union. The number of holiday homes is much smaller there than in Grímsnes, the tarfiffs will be somewhat higher as the investment will be distributed onto fewer customers.

5.2 Hlíðaveita Tthe district heating service Hlíðaveita, which has been in operation since 1980’s, was recently aquired by Reykjavik Energy. Hlíðaveita was originally built to service approximately 15 farms located in the vicinity of the geothermal field that is utilised. With increased contruction of holiday homes in the area that have been hooked onto the DH system and the fact that the district heating service was primarily designed to service farms, it does not come as a surprise that the service is in need of restructuring. Reykjavík Energy sees the potential in the area as a holiday home area servicing more than 500 homes within few years. The DH service will be restructered and build according to the model used in Grímsnes.

6 Summary Based on the experience from Grímsnes, we are convinced there is a future for district heating services in holiday home areas and other sparsely populated areas. We have considerable knowledge about the market and learned much, which will come in handy in future projects of similar kind during the construction phase.

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The geothermal heat pump boom in Switzerland and its background

L. Rybach1),2) and Th. Kohl1),2)

1) Institute of Geophysics ETH Zurich, 2) GEOWATT AG, Zurich [email protected]

Abstract

Geothermal heat pump systems spread out rapidly in Switzerland, with annual increase rates up to 15%. The reasons for rapid market penetration are technical, economic, and environmental. In 2001, the total installed capacity of GHP systems was 440 MWt, the energy produced about 660 GWh. With over 1 GHP units every 2 km2 their areal density is the highest worldwide. This secures Switzerland a prominent worldwide rank in geothermal direct use.

Keywords: market penetration, technical, environmental and economic incentives, growth rates.

1 Introduction At present there are over 25,000 geothermal heat pump (GHP) systems in operation in Switzerland. With over 1 GHP units every 2 km2 their areal density is the highest worldwide; new systems are installed with an annual rate of increase >10%. Small systems (<20 kW) show the highest growth rates (>15 % p.a.). There are three types of heat supply from the ground: shallow horizontal loops (<5% of all GHPs), borehole heat exchangers (100-400 m deep BHEs; 65%), and groundwater heat pumps (30%). The GHP systems rapidly spread out in Switzerland; alone in 2002 a total of 600 kilometer boreholes have been drilled to be equipped with BHEs. The aim of this paper is to present the current situation in Switzerland as well as the reasons for this remarkable boom. Much of the material originates from a statistical survey of geothermal energy utilization in Switzerland in 2000 and 2001 (Kohl et al., 2002, carried out for the Swiss Federal Office of Energy).

2 Reliability and sustainability GHP systems are ideally suited to tap the ubiquitous shallow geothermal resources. The reliability of long-term performance of GHP systems is now proved by theoretical and experimental studies as well as by measurement campaigns conducted over several heating seasons (Eugster and Rybach, 2000). Seasonal performance factors >3.5 can be achieved. The studies were performed at a commercially installed GHP system with BHE in Elgg, near Zurich. During the production period of a BHE, the drawdown of the temperature around the BHE is strong during the first few years of operation. Later, the yearly deficit decreases asymptotically practically to zero. During the recovery period after a virtual stop-of-operation, the ground temperature shows a similar behavior: during the first years, the temperature increase is strong but tends with increasing recovery time asymptotically towards zero (Figure 1). The time to reach nearly complete recovery depends on how long the BHE has been operational. Principally, the recovery period equals the operation period.

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The measurements and model simulations prove that sustainable heat extraction can be achieved with such systems (Rybach and Eugster 2002). The installation in Elgg supplies about 13 MWh per year on the average. In fact, the BHE’s show stable and reliable performance, which can be considered renewable. Reliable long-term performance provides a solid base for problem-free application; correct dimensioning of BHE-coupled GHPs gives great scope of widespread use and optimisation. In fact, the installation of GHPs, starting at practically zero level in 1980, progressed rapidly and provide now the largest contribution to geothermal direct use in Switzerland, as revealed by statistical data.

0 10 20 30 40 50 60Time [years]

-2.0

-1.5

-1.0

-0.5

0.0

0.5

Tem

pera

ture

cha

nge

[K]

-2.0

-1.5

-1.0

-0.5

0.0

0.5

production period recovery period

∆T

Figure 1: Calculated temperature change at a depth of 50 m and in a distance of 1 m from a 100 m deep BHE over a production and a recovery period of 30 years each (from Eugster and Rybach, 2000).

3 Statistics, trends of growth A statistical data compilation and evaluation, performed to assess the geothermal energy usage in Switzerland for the years 2000 and 2001 (Kohl et al., 2002) reveals that GHPs contribute with 634 GWh in 2001 over 62% to the total geothermal heat production (Table 1).

Table 1: Direct use of geothermal heat in Switzerland (from Kohl et al. 2002).

Energy source / use Heat produced in 2001 (GWh)

Percent of total (%)

GHP with borehole heat exchangers (incl. shallow horizontal loops)

532 52.3

GHP with groundwater 102 10.1 Thermal springs/boreholes (balneology) 322 31.7 Deep aquifers 37 3.7 Tunnel waters 14 1.3 Deep borehole heat exchangers 1 0.1 Geostructures 9 0.9 Total 1018 100.0

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The installation of GHP systems in Switzerland proceeds since their introduction in the late 70ties at high speed: Figures 2 and 3 show the impressive growth.

Number of Ground Coupled Heat Pump Systems

02'0004'0006'0008'000

10'00012'00014'00016'00018'00020'000

1980 1985 1990 1995 2000

Year

# (P

<50

kW)

0

100

200

300

400

500

600

700

800

# (P

>50

kW)

< 20 kW20 - 50 kW50 - 100 kW> 100 kW

Figure 2: Development of geothermal heat pump installations in Switzerland in the years 1980-2001. From Kohl et al. (2002).

Thermal Power [MWt]

0

50

100

150

200

250

300

350

400

450

1980 1985 1990 1995 2000

Year

Groundwater HP Systems

Ground coupled HP Systems

Figure 3: Development of installed capacities (MWt) of BHE-coupled (top) and groundwater-based (bottom) geothermal heat pumps in Switzerland during the years 1980-2001 (from Kohl et al., 2002).

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The annual increase rates are remarkable: the number of newly installed systems increase with an annual rate of >10%. Small systems (<20 kW) show the highest growth rate (>15% p.a., see also Figure 2). In 2001 the total installed capacity of GHP systems was 440 MWt, the energy produced about 660 GWh. With over 1 GHP units every 2 km2 their areal density is the highest worldwide.

4 Reasons for rapid market penetration The main reason for the rapid market penetration of GHP systems is that in Switzerland there is practically no other resource for geothermal energy utilization than the ubiquitous heat content within the uppermost part of the earth crust, directly below our feet. Besides, there are numerous and various further reasons: these are technical, environmental, and economic. Technical incentives • Appropriate climatic conditions of the Swiss Plateau (where most of the

population lives): Long heating periods with air temperatures around 0°C, little sunshine in the winter, ground temperatures around 10-12°C already at shallow depth.

• The constant ground temperature provides, by correct dimensioning, a favourable seasonal performance factor and long lifetime for the heat pump.

• The GHP systems are installed, to fit individual needs. Costly heat distribution (like with district heating systems) is superfluous in a decentral manner.

• Relatively free choice of position next (or even underneath) to buildings and little space demand inside.

• No need, at least for smaller units, of thermal recharge of the ground; the thermal regeneration of the ground during heat extraction breaks is continuous and automatical.

Environmental incentives • No risk with transportation, storage, and operation (as e.g. with oil). • No risk of groundwater contaminations (as with oil tanks). • The systems operate emission-free and helps to reduce greenhouse gas emissions

like CO2. Economic incentives • The installation cost of the environmentally favourable GHP solution is

comparable to that of a conventional (oil based) system (Table 2). • Low operating costs (no oil or gas purchases, burner controls etc. like with fossil-

fueled heating systems). • Local utility electricity rebates for environmentally favourable options like heat

pumps. • A CO2 tax is in sight (introduction foreseen for 2004). Further incentives and reasons for rapid spreading of GHP systems is “Energy Contracting” by public utilities. The latter implies that the utility company plans, installs, operates, and maintains the GHP system at its own cost and sells the heat (or cold) to the property owner at a contracted price (cents/kWh).

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Table 2: Comparison of BHE/HP installation and operation cost with a conventional oil burner heating system (from Rybach, 2001). BHE

(1 BHE 90 m) Oil burner

(Tank 2x2000 l) Basis: heating demand 6.5 kW Heating energy need per year (kWh/a) 13,600 13,600 System efficiency (%) 95 80 Seasonal Performance Factor 3.5 - Effective energy used (kWh/a) 4,900 17,000 Fuel consumption (liter/a) - 1,703 Space required (m3) 2.6 23 CO2 emission (tons/a) - 3.8 Installation costs (CHF; Swiss francs)* Complete system incl. storage 12,730.- 16,300.- BHE 11,010.- - Space in house (400.-/m3) 1,040.- 9,200.- Miscellaneous costs (trenches, chimney...) 1,620.- 1,600.-

4.1.1.1 Total 26,400.- 27,100.-

Energy costs (per year, CHF) Electricity, high tariff 337.40 49.- Electricity, low tariff 224.95 22.- Basic payment 102.- 8.- Fuel cost (68.-/100 l)** - 1,158.- Total 664.35 1,237.- Running costs (per year, CHF) Maintenance 150.- 370.- Chimney cleaning, smoke gas control - 180.- Total 150.- 550.- *) 1 CHF = 0.74 US$ (as of March 2003); **) Price in March 2003

5 Novel solutions, outlook Whereas the majority of GHP installations serve for space heating of single-family dwellings (± sanitary water warming), novel solutions like multiple BHE’s, combined heating/cooling, “energy piles” are rapidly emerging. • Multiple BHE’s: There is a tendency to increase the size of geothermal

installations by using a multitude of BHE’s. Extensive studies are being carried out to determine optimum depths and borehole spacings in order to guarantee an economic life span. As an example, the BHE field with 2x49 160 m deep BHE’s at the Technology Park in Root/LU can be mentioned.

• Combined heat extraction/storage: Multiple BHE’s can also be used to access a ground storage volume for seasonal storage of waste heat from large buildings or with solar energy (solar collectors, flat building roofs, surfaces of streets or parking areas). Several such installations work satisfactorily, e.g. the road bridge snow/ice melting system SERSO at Därligen/BE with 91 65 m deep BHE’s, no heat pump.

• Heating/cooling: Climatic warming leads, even within the meteorological conditions of Switzerland, to an increasing demand for climatization. Therefore, GHP operation in the combined heating/cooling mode is increasingly popular,

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especially for larger building complexes like factories. As an example, the BHE field with 32 BHEs, each 135 m deep each at the Meister jewellery factory in Wollerau/ZH can be mentioned.

• Geostructures, “Energy piles”: Foundation piles can be equipped with heat exchangers. A prominent example represents the new Terminal “Dock Midfield” at the Zurich Airport (315 piles, 30 m deep each), for heating and air-conditioning.

6 Conclusions • Geothermal heat pump (GHP) systems spread out rapidly in Switzerland; at

present there are over 25,000 geothermal heat pump systems in operation. In 2001, the total installed capacity of GHP systems was 440 MWt, the energy produced about 660 GWh.

• New systems are installed with an annual rate of increase >10%. Small systems (<20 kW) show the highest growth rates (>15% p.a.). The reasons for rapid market penetration are technical, economic, and environmental.

• GHP systems with borehole heat exchangers (BHE) are the most frequent types of heat supply from the ground. Alone in 2002 a total of 600 kilometer boreholes have been drilled to be equipped with BHEs.

• With over 1 GHP units every 2 km2 their areal density is the highest worldwide; this secures Switzerland a prominent rank in geothermal direct use (for installed capacity per capita among the first five countries worldwide).

• The main reason for the rapid market penetration of GHP systems that in Switzerland there is practically no other resource for geothermal energy utilization than the ubiquitous heat content within the uppermost part of the earth crust, directly below our feet. Besides, there are numerous and various further reasons: these are technical, environmental, and economic.

• Novel solutions (multiple BHEs, combined heat extraction/storage e.g. of solar energy, geothermal heating/cooling, “energy piles”) are rapidly emerging.

Acknowledgements Generous support by the Swiss Federal Office of Energy and, especially, by Markus Geissmann and Harald Gorhan is gratefully acknowledged.

7 References Eugster, W.J., Rybach, L. (2000). Sustainable production from borehole heat exchanger systems. In: Proc. World Geothermal Congress 2000, Kyushu-Tohoku, Japan, p. 825-830. Kohl, Th., Andermatten, N., Rybach, L. (2002). Statistik Geothermische Nutzung in der Schweiz für die Jahre 2000 und 2001. Report to Swiss Federal Office of Energy Bern, 25 p. Rybach, L. (2001). Design and performance of borehole heat exchanger/heat pump systems. Proc. European Summer School of Geothermal Energy Applications, Oradea/Romania (CD-ROM). Rybach, L., Eugster, W.J. (2002). Sustainability aspects of geothermal heat pumps. Proc. 27th Workshop on Geothermal Reservoir Engineering, Stanford University, California/USA (CD-ROM).

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Medicinal tourism in Hungary Oasis-farm Benő Rátóti Dr., Ph.D. cartographer, geologist

Member of Hungarian Geothermal Association Budapest, Tavaszmező u. 1., Hungary 1084

Abstract

Hungary is located in the central part of Europe, in a basin sorrounded by the Carpathian Mountains. During Pliocene this basin was covered by the so-called Pannonian Sea which reached its maximum extent in this period. The 3-4000 meter thick sedimentary sequence deposited in this time facilitated the formation of thermal-waters in which Hungary became considerably rich. This paper is aimed at presenting this woderful natural resource. Scientific investigations conducted so far provided fundamental knowledge on it. Our objective is the most costeffective utilization of these waters – natural sources or driven wells – ascending to the surface. The opportunities are diverse. In the Oasis-farm we try to demonstrate its aspect associated with medicinal tourism considered as a new, original proposal. The complex use of thermal-waters (integrated multipurpose thermal-water system) seems to be a successful solution. In order to demonstrate our concept we selected a region in the central part of the country covered by dry and poor soil but rich in thermal-waters. The description of geographical, geological and geothermal settings, the brief account on the historical development of spa-culture and the presentation of the geographical values of Hungary as well as its potential in the given subject provide the background necessary to understand the article. In some of the following paragraphs we draw up the conceptual structure of the Oasis-farm, the “circulation” of thermal water within the farm, the technical solutions, and the “centre” concept of the farm as well as the related establishments (spa-hotels), sports and recreation facilities and different bathing-pools, etc. of the complex. The so-called “circle round the moon” is also addressed together with the small boarding houses, farms for hoarse-riding, etc. These latters reinforce the centre character of the Oasis-farm, since the all year round operation of the farm can give a new impulse to its continuous attendance.

Keywords: balneotherapic hospital, thermal-water, recreational "oasis" establishments.

1 Geographical, geological and geothermal background Hungary is located in the central part of the Carpathian Basin, its flat plains are dotted by rolling hills, block-mountains and areas of past volcanic activity. Beeing surrounded by the Carpathian Mountains the country’s surface has a basin-like character. The basin of the Pannonian Sea, reaching its biggest extent in the Pliocene, had sunk whereas its edges had risen. These geohistoric events are indicated by a 3-4000 meter thick diversified sedimentary sequence deposited in the Pannonian Sea. The mineral- and thermal-waters utilizied nowadays originate from the upper 500-2000 meter thick buried sedimentary complex. The miscellaneous types of waters have different medicinal properties and are useful for preventive treatment and recovery from illness of 9 different types as well as providing recreation and relaxation.

2 Historical development and spa-culture The usefulness of thermal-waters for medical treatment was discovered by the Celts 4000 years ago. The Romans used them for recreation and recovery and the Turks developed spas in the 16th and 17th centuries. The baths built by the Turks (Rudas, Rác, Király, Lukács, Eger) are still in use today and are famous all over the world.

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The spa-culture had developed further in the following centuries: Hévíz 1785, Harkány 1824, Margitsziget 1867, Városliget 1878. Famous spas, such as Hajdúszoboszló, Bükfürdő, Balf, Debrecen, Gyula, Zalakaros etc., were built in a recent wave of balneological interest. According to a survey made in 2000, there are 1289 known thermal springs in Hungary with temperatures between 30-100°C; the number of thermal-baths is 243, which are located in 50 settlements.

3 Geographical values of Hungary Beyond the thermal-waters Hungary has several other values for the benefit of visitors, such as its location, climate, diversified topology, varied agricultural regions and the influence of ample sunshine (2000-2200 hours) on the quality of agricultural products. These factors all together promote both domestic and international medicinal tourism. Furthermore there are several contemporary sights, the archeological findings of earlier millennia, the still existing monuments, excavation findings, traditions, the heritances of thousand of years old culture.

4 Perspective In Hungary the geothermal gradient is very advantageous for geothermal activity. While the continental average is 33 meters per °C, it is 16-22 meters in this country. Considering the rise in temperature: in 1000 meters depth the world average is 30-35°C, whereas the domestic one is 60-70°C. The highest values are obtained by the drillings in the Great Hungarian Plain (Alföld). It has also to be noted that geothermal energy (earth-heat) is a form of environmentally friendly and renewable energy as compared to fossil energies (coal, oil, natural gas). The given opportunities, the word ranking thermal-water reserves (e.g. heat capacity of our dynamic thermal-water reserve is equivalent to about 1,5 million tons of oil per year) are fortunate fundamentals on which we can plan for longer periods – as earlier mentioned, since earth-heat renews itself and it is renewable on the scale of human existence. The idea of OASIS-FARM was promoted at the beginning of the “nineties”. Two-thirds of the surface of our country is underlain by a thermal-lake. As indicated on Figure 1, wells can be located almost all over the country. More than 3000 deep wells have been completed so far (hydrocarbon drillings), and these, mostly closed wells are suitable – in case of need and opportunity – for thermal-water production.

Map 1: Significant thermal-springs.

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In Hungary many medicinal hotels and medical thermal-baths operate, but there are “blank spots” in many places with all the necessary resources available like the Alföld, where new establishments are missing. We wish to set up the OASIS on these areas.

Figure 2: Thermal-waters (oasis).

4.1 Some comments on the construction of OASIS-FARMs The OASIS-FARM is a new kind of tourist-, convalescent holiday-, therapeutic-, entertaining establishments, planned to be on thermal-springs. This new facility is to be a spectacular, independent bioestate with the objective of multiple integrated use of the water of geothermal springs – like thermal-water supply of medical institutions, heating of buildings and green-houses, acquisition of medical – mud by sedimentation, etc. The “OF” projects are planned to be completed on dry grounds in the central part of the Plain, in areas of low productivity (e.g. in the vicinity of Kecskemét–Helvécia). The “OF”-s – depending on their individual thermal-water composition – would be different economic units each with their own unique set of characteristics in therapy, tourism and recreation. The intended sites in the above-mentioned region are the dryest areas in the country (precipitation 450-500 mm per year, 200-250 mm between April–Sept.), where the main temperature between April–September is 18°C and 75% of the 2000-2200 hours of early sunshine occurs during these months. Warm climate with dry, hot summers and droughts is perfect for summer vacationing and bathing.

5 “Circulation” of thermal-water at the “OF” project The complex use of thermal- and medical-waters at Oasis-Farm (integrated multipurpose thermal-water system) connects the entire path of circulation of thermal-water produced by the wells. Further on we outline its key methods and technics based on the Helvécia Project. We have to point out that our aim in designing this complex system is to utilize the thermal capacity of the thermal-water with as small a heat-loss as possible. At the beginning of the process the 60-70°C warm thermal-water is carried from springs to bio growing green-houses through fitting pipelines (closed system free from pollution), then on to bio stock-raising buildings (closed system), where – according to earlier calculations – the water cools down to 30-38°C degrees suitable for bathing; this water then supplies the open-air pools and those inside the hotel. Another spring – with the required higher temperature – supplies heat for hotel-rooms

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and medical-buildings and provides steam baths, hot-water basins needing a higher temperature etc. Thermal- (medical-) waters – after the previously outlined usage – uniformly flow into settling ponds, which are working gravitationally, with straines. These filter beds arranged in tiers ensure the utilization of grains with different size. The No. 1. settler catches the rough-grained mud (medical mud). The No. 2. settler catches the fine-grained one (row material for ointments, materials for curative massage and cosmetics). The No 3. settler is a natural pond (fishing pond) which stores the cooled-down, lukewarm, nature-protective water and carries it continuously in a controlled manner to a drainage system (overground streams), to bio-horticulture facilities or to the ponds and creeks of golf-course with lower exposure. The complex usage is cost-effective, preserves the environment and fits to natural circulation. Recent target-surveys prove that thermal-waters utilized as described above, cause relevant pollution in surface waters and in the soil. Accordingly, the sand ridge waters, utilized by Oasis complex system, don’t need recuperation. It solved a problem hotly discussed in Hungary. The latest experimentary measurements reinforce namely that thermal-waters, after this utilization, cause only unsignificant local pollution in surface – or groundwater – that can be considered negligable. Moreover the ratio of detritic, porous (mainly Upper Pannonian) sandstone is 87% in Hungary. In this kind of aquifers –there is not any operative recuperation according to international experience.

6 Other available facilities and possibilities Apart from its medical-services described above, the OASIS-FARM – in this case Helvécia, provides a wide range of services through the complex use of thermal-water: bioproducts of its own raising (plants, animals); horse-tours, hunting in nearby forests, pleasure rides, medical-horse riding, water fun-fair; promenades and educational-trails in the planned parkforest, post-glacial native plants in its gardens, professional lectures on the plants, organized excursions, bicycle tours, sporting establishments such as tennis-courts, golf-course, indoor sports hall, indoor swimming pool, racing pool, sporting events and many other, already existing entertainment facilities in the Farm theatre, in the small pensions and in roadside inns. The neighbourhood is a perfect pleasure ground with excellent specialities of Hungarian cuisine.

7 Summary of the types of geothermal fluids available in the region

Table 1 (at the end of the paper) presents the most important and most characteristic mineral- and thermal-waters of Hungary, which are suitable both for medical treatment, bathing and for drinking cure. Map 1 outlines the regional distribution of the more than 3000 sources and driven wells. The richness of the Great Hungarian Plain in thermal-water is clearly manifested. Table 2 (at the end of the paper) provides additional data on the oasis area represented on Map 2 concerning the composition of the water of non-active (closed) wells and those to be penetrated later all in the surroundings of operating thermal-springs (medical spas). Both tables offer thus an overview on the water types and therapeutical opportunities. The first table provides a countrywide picture, whereas the second one presents operating spas in the Great Hungarian Plain as well as the potential of wells in the planned oasis farm.

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Waters of alkaline-bicarbonate content: this kind of water occurs in the Szappanszék lake, at Nagyszénás, Szolnok, Abony, Gyopárosfürdő and Kalocsa. Waters of sulphate content: these waters spring forth of the three wells of Jászkarajenő and Tiszajenő. Waters of iodine-bromine content: they can be observed at Cserkeszőlő, Karcag (two springs), Szolnok, Túrkeve, Cegléd, Tiszaföldvár and Kiskőrös. Waters of alkaline-bicorbonate and sodium-chloride content: they occur in the Szappanszék lake at Fülöpháza.

8 The role and future of the CENTRE OASIS-FARM of HELVÉCIA – medical hotel, curative resort, spa, entertaining centre. I presented Helvécia (Helvetia) as the prototype of oasis-farm projects in order to introduce the original idea of the complex utilization of thermal-waters (integrated multipurpose thermal-water system). In this frame I described the system of a so-called oasis-resort, sanatorium and entertaining facilities that can serve as an example for setting up further oasis-resorts. They would be different from the prototype in the aspect of the relevant thermal-water compound that will define the scope of related medical activities. The “Centre” – represented on the layout map of the project – becomes virtually the centre of the complex due to its central position and its establishments. The row of hotels ensures not only rest and entertainment, but several facilities are suitable for cultural programs (concerts, film premières) and meetings, business negotiations. Accomodation in the planned OASIS-FARM (4th or 3rd class) Spa-hotels 4 individual hotels 200 rooms about 600 lodgings 20 apartments about 100 lodgings Camping about 500 lodgings Pensions (still existing) about 300 lodgings Total: about 1500 lodgings In the buildings there are meeting-rooms (50-100 seats) and club-rooms. The consulting-rooms from medical- and natural-treatments, for fittness and wellness are located in the same buildings. The assortment of recreation and games (bowling etc.), conditioning, salt-cave, subaqueous traction bath and pelotherapy can be found in the underground rooms. The sporting establishments give opportunity for non-stop running, also during the winter-season. On one side of the inner thermal swimming pool the following facilities will be established: small basin with different size and temperature, a tropical indoor basin; on its other side: steam bath, dry steam, adventure bath, bubble bath, sauna, solarium, cosmetics and snack-bar. In the park thermal-water and cold-water basins – in the aquatic fun fair several children’s bath would be set up. Some hundred meters away from the Farm there is an already functioning three-storey hotel (elder people’s home). This institution has pension with thermal-heating, indoor thermal-pool, library etc. Its active thermal-well supplies water with high mineral content and low hardness, including alkaline-bicarbonate, sodium chloride, iodine and fluoride.

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To establish these OASIS-FARMs we are looking also for foreign investors to turn our thermal-water treasure to international advantage. Building upon the plans described above, Hungary has- in our view – the opportunity to become the medical- and resort-centre of the European Union.

9 References Árpási, Miklós. (2002). Extension of geothermal-energy in Hungary. National Atlas of Hungary. Research guided by the GEOGRAPHICAL RESEARCH INSTITUTE of the HUNGARIAN ACADEMY OF SCIENCES. Editorial Board, chairman: Márton Pécsi (1989) Rátóti, Benő. (2000). Project for Helvécia and surroundings, 52 pages. Schulhof, Ödön (ed.). (1957). Mineral- and medical-waters of Hungary. Szirtes, Lázló. (1985). Balneology, Rehabilitation, Medical-bath business 2. 10 pages.

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Table 1: Major mineral and thermal-waters.

Serial number

Waters Cation Anion Salt Site of important spring

1. Waters of alkaline bicarbonate content

Na+ (natrium)

HCO-3

(hidrokar-bonát)

NaHCO3 (nátrium-hidrokar-bonát)

Bükkszék (Salvus) Parád (Csevice) Balf, Bikkszád

2. Waters of Ca-Mg bicarbonate content

Ca2+ (kalcium) Mg2+ (magnézium)

HCO-3

(hidrokar-bonat)

Budapest (Hungária) Moha (Mohai Ágnes) Parád (Szent István)

3. Waters of Glauber(‘s) Salt natronsulphate content

Na+ (natrium)

So2-4

(szulfát) Na2SO4 (nátrium-szulfát)

Jászkarajenő (Mira)

4. Waters of sulphate content

Mg2+

(magnézium) So2-

4 (szulfát)

MgSo4 (magnéziumszulfát)

Buda (Hunyadi János, Apenta, Igmæandi, Ferenc József, Mira)

5. Waters of sodium content

Na+ (natrium)

Cl- (klorid)

NaCl (nátrium-klorid)

Kolop (Máriakút)

6. Waters of iodine (bromine) content

Na+ (natrium)

Cl- (klorid) J- (jodid)

NaCl (nátrium-klorid) NaJ (nátrium-jodid)

Sóshartyán, (Jodaqua) Debrecen, Hajdú szoboszló, Pesterzsébet Eger (Dobó-forrás)

7. Waters of iron content

Fe2+ (vas)

HCO-3 (hidrogénkarbonát) SO2-4 (szulfat)

Parád (Csevice) Görömbölytapolca; Sikonda, Csopak

8. Waters of arsen content

As3+ (arzén)

Parád

9. Carbonic acid waters

H+ (hidrogén)

CO2-3 (karbonát)

Szeged (Anna-forrás), County of Borsod, Fonyód, Harkány

10. Waters of sulfuric content

H+ (hidrogén)

S2- (szulfid) CO2S2- (tiokarbonát)

Parád (Csevice) Harkány, Budapest (Lukács, Margitszigeti, Széchenyi), Balf

11. Waters with radioactive substance

Budapest (Rudas, Juventus-forrás) Hajdúszoboszló, Hévíz, river bed of Maros (radioactive mud)

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Table 2: Thermal- and medicinal baths.

Thermal baths town name and address opening hours type of water effects of the bath Jászapáti Open-air Bath 1 May – 15 September plain thermal water rheumatic problems Jászárokszállás Thermal and 1 May – 31 August plain thermal water post-traumatic therapy, Open-air Bath rheumatic problems Thermal and thermal bath: throuthour thermal water with paralysis, locomotor Open-air Bath the year, open air bath: alcali hydrogen diseases, bone and 1 May – 31 August carbonate joint diseases Jászberény Open-air Bath 1 June – 31 August plain thermal water rheumatic problems Jászboldogháza Open-air Bath 1 June – 31 August plain thermal water locomotor diseases Jászszentandrás Open-air Bath 1 May – 30 September thermal water with iron rheumatic and gynaecological diseases Open-air Bath 1 May – 30 September thermal water with locomotor, gynaecological Karcag high salt content, diseases, disorders of hydrogen carbonate, the spine calcium Kisújszállás Open-air Bath 1 June – 31 August thermal water with alcali exophthalmic goitre, cydrogen carb. and iodine hyperacedity Kunhegyes Open-air Bath 1 May – 30 September thermal water with iodine Open-air Bath 1 June – 31 August mineral water with Martfű alcali hydrogen carbonate Open-air Bath swimming-pool: thermal water with rheumatism, problems Mezőtúr throughout the year high salt content, alcali with the joints, allergy open-air bath: hydrogen carbonate, 1 May – 31 August iodine and fluor Damjanich swimming-pool: thermal water with high rheumatism, problems Swimming-pool throughout the year salt content and alcali with the joints open-air bath: hydrogen carbonate 1 May – 31 August Szolnok Open-air Bath 15 June – 31 August thermal water with rheumatism, natrium hydrogen gynaecological diseases carbonate MÁV Swimming-pool 15 June – 31 August plain thermal water and Open-air Bath Thermal and 1 May – 30 September thermal water with rheumatism, problems Tiszaföldvár Open-air Bath alcalichloride and hyd- with the joints rogencarbonate Tiszaörs Bath thronghout the year plain thermal water Open-air Bath 1 May – 30 September thermal water with post-traumatic therapy, Törökszentmiklós high iron content problems with the Spine, and the nervons system.

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Medicinal baths

town name of the bath type of water effects services

Berekfürdő Medicinal and Open-air Bath

alcali hydrogen carbonate, iodine

locomotor diseases, inflammations

posttraumatic therapy

massage, traction bath, mud-pack, chiropody

Cserkeszőlő Medicinal and Open-air Bath

iodine, bromide, chloride

rheumatic, locomotor and gynaecological

diseases, posttraumatic therapy

massage, traction bath, mud-pack, chiropody

Szolnok Hotel Tiszia and Medicinal Bath

alcali hydrogen carbonate

locomotor diseases, reduction of hyperacidity

basic medical examiination check up, Turkish bath, traction

bath, mud-pack, sauna, medical massage,

gymnastics, chiropody, dental therapy

Tiszafüred Thermal and Medicinal Bath

alcali hydrogen carbonate

locomotor diseases, vertebral disk

problems, nervous disorders combined

with athropy

massage, traction bath, gymnastics

Túrkeve Open-air Bath alcali hydrogen

carbonate, iodine, sulphyde

locomotor, gynaecological, dermatological

problems

tub-bath, chiropody

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