heat pump centre

Table of Contents

Contents

News & Views

General ......... ... ....... ......... ............ ......... ............ .. .... ... ... ... ... 4

Technology & Applications ............................ .. ..................... 7

Markets ........... .. ........ .... .. ........... ........... .. ............................ 8

/EA Heat Pump Programme ................................................ 7 0

Articles on Heat Pumps and the Environment

Heat Pumps and the Environment- an International

Overview ................... ........................ .. ..... .. ................. ...... 7 2

The Environmental Case for Heat Pumps ........ .. ........... .. ..... 7 5

Small Heat Pump Air Conditioners - The Environ-

mental Impact of their Rapid Growth ........ ...... ............ .. ..... 7 1

Global Warming Impacts of Chillers .................................. .. 7 9

Heat Pumps in the UK - An Assessment of the

Environmental Impact ...................... .... ....... ... ........ .. .... ...... 22

Reducing C02 Emissions - How do Heat Pumps

Compete with Other Options? ............................................ 24

Non-Topical Article

Taking a Measured Approach - Heat Pump Promotion

in Switzerland ............................... .. ....... ........ .... ........ .. .... .. 2 7

Regular Features

Comment ............ ........ .. ....... ... ... ........ .. ........... .................... 3

Bibliography ... .. .. .... ..... .... ... .. .... .... .... ...... ... ...... .. ... ... .......... 29

Conferences ..... .. ..... ......... ....... .... .. ........... .. ...... .. ... .. ........... 30

Publications ............. .......................................................... 3 7

National Team Contacts ... ............................ .. ............ .. ..... 32

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IEA Heal Pump Centre N ewsleffer

Front Cover: Installing a water-to-water electric heat pump in this recenlly res tored 19th century building, al Lugano Lake, Switzerland, benefitled the environment by avoiding an annual emission of 4.8 tonnes co,.

International Energy Agency The International Energy Agency ( /EA) was established in 1974 within the framework of the Organisation for Economic Cooperation and Development (OECD) to implement an lnlemational Energy Programme.

A basic aim of the /EA is to fos ter cooperation among the 2 3 /EA participating countries to increase energy security through energy conservation, development of alternative energy sources, new energy technology, and research and development (R&D). This is achieved, in part, through a programme of energy lec/1110/ogy and R&D collaboration currently with in the framework of 35 Implementing Agreements, containing a total of more than 60 separate collaboration projects. This publication forms one element of this programme.

/EA Heat Pump Centre, 1993. The nine member countries of the /EA Heat Pump Centre (HPC) form a network for exchanging information on heal pump technology. By increasing awareness and understanding worldwide, the HPC aims lo accelerate the implementation of heal pump technology as a means lo reduce energy consumption and thereby lo limit harmful environmental effects. This publication is one element of the HPC activities.

Any part of this publication may be reproduced, with acknowledgement lo the /EA Heat Pump Centre, Sittard, the Netherlands.

Edltl11g/ Prod11ctio11: Lucinda Madagan I Roswilha Muyres I Heleen Smeets. Tec/Jnical Editi11g: /os Bouma I Berl Stuij I Mike Steadman. Illustrations: Offermans EPS, Moostricht. Pri11ters: Huntjens Drukkerij, Stein.

ISSN 0724-7028

Vol. 11 , No. 3, 1993

IEA Heat Pump Centre Newsletter Topical Article

Global Warming Impacts of Chillers

As users and policy makers look f or altematives to using traditional CFC refrigerants in chillers, it is important that the e11viro11me11tal co11seque11ces of the altematives are f ully understood. A new study by the author makes a thorough exami11atio11 of the global warming impacts of using compression chillers with altemative refrigerants, or of switching to absorption technologies. Extending earlier work 011 tile net global warming impact of refrigerants, tile study uses a systems rather than a components approach. The findings give furth er evidence that once CFCs are phased out, measures such as improving energy efficiency and reducing emissions, are far more significant than the choice among refrigerants. The study also shows that direct-fired abso111tio11 chillers add more to global warming than do vapour-compression machines.

* * *

With the phase-out of CFCs, chiller manufacturers have three primary refri gerant options: HCFC-22 (high pressure), HCFC-123 (low pressure) and HFC-1 34a (medium pressure). Whil e propane and ammonia are also candidates, flammabili ty and toxicity concerns limit their use. Absorption systems also are an option, w ith the working pairs ammonia/water used in small capacities (generally< 60 RT or 210 kW), and water/ lithium bromide for larger units.

James M. Calm, USA

Total Equivalent Warming Impact When determining the global warming impact of the refrigerant options, both the d irect effect (from refrigerant emissions) and the ind irect effect (associated with the energy consumption of the equipment) should be considered. By expressing both the direct (chemica l) and ind irect (energy-related) effects as equ ivalent carbon d ioxide emissions, a net effect referred to as the Total Equiva lent Warming Impact (TEWI) can be calculated. This approach was used in a study conducted by Oak Ridge Nationa l Laboratory and Arthur D. Li ttle Inc. for the Alternative Fluorocarbons Environmental Acceptabi lity Study (AFEAS) and the US Department of Energy (DOE) (see HPC Newsletter Vol. 10, No. 3 pp. 22-25) .

New Study A new study (see References) by the author, sponsored by the US Electric Power Research Institute (EPRI), focuses on the global warming impact of ch illers. This study used a more rigorous methodology to calculate the global warming impacts of power generation. The data used included the projected fuel mix and the transmission, distribution and o ther losses in the United States in 1995. Net greenhouse emissions have fa llen steadily as the efficiency of power plants has improved. Similarly, generation using non-fossil energy sources, including nuclear, hydro, and - to a lesser extent - geothermal, w ind, and so lar, has

D Direct - refrigerant D Indirect - gas

CJ) c

'§ 100 -+-r--~----l ~ (ii .0 0 O>

~ ~ 50 <ti 0. E 0 0

CFC- HCFC- CFC- HFC- HCFC-11 123 12 134a 22

Reference system cost

Vol. 11 , No. 3, 1993

D Indirect - electric

CFC- HCFC- H20 / 11 22 LiBr

Absorption chiller cost

Figure 1: Net global warming impacts of 300 RT (1 MW) vnpo11r­compressio11 and do11ble­effect absorption chillers.

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Topical Article

Figure 2: Regio11nl globnl wnrming impacts of chillers i11 the United Stntes.

Ol c ·~ 100-+-- ------­<ll ~

2 0

°' Q)

£ ·~ a. E 0 0

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IEA Heat Pump Centre Newsletter

Ell Direct - refrigerant Ill I ndi reel - gas • Indirect - electric

HCFC-123 Vapour . HCFC-22 }

HCFC-134a compression

0 West West East North- South South-

Direct-fired absorption (water I lithium bromide)

central central east central east

increased. The study also considered the regional differences of power generation in the United States.

The calculations of indirect emissions were adjusted to reflect seasonal and hourly changes in both ch iller loads and generation fu els. For example, hydroelectric power, which does not contri bute to globa l warming, is most abundant in the winter and spring, but the highest cooling loads genera lly occur in the summer. Similarly, gas turbines, which are widely used to meet peak generation needs (often driven by air cond itioning loads), generally produce less C02/kWh of electricity generated than do base-load, coal-fired plants.

The study also used updated data for refrigerant Global Warming Potentials (GWPs) and examined the impacts of improved equipment efficiency and refrigerant management practices. The energy required by condenser water pumps, and cooling towers was included. Condenser fan power also was included for air-cooled equipment, as was the solution pump power for absorption systems.

Findings Figure 1 compares the net g lobal warming impacts for electric vapour-compression chillers, and for a gas­fired, double-effect absorption chiller using water/ li th ium bromide. Also shown are two very high­performance vapour-compression ch illers with the same fabrication costs as the absorption chiller. The performance of th ese machines was estimated by chiller manufacturers to be the minimums atta inable at this cost. They are not marketed, however, since the cost increm ents over standard equipment are much higher than the efficiency improvements.

Figure 1 shows that w hile the efficiencies analyzed for the alternative refrig erants were slightly lower than for the CFCs, the lower GWPs of these refrigerants more

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than offset the difference. As shown, the indirect (energy-related) components of global warming far exceeds th ose from the direct ( refrigerant) effects. In addition, all the vapour-compression machines yielded lower net g lobal warming impact than the direct-fi red, double-effect absorption chi ller.

Regional Analysis Figure 2 shows t he variation in net global warming impact for chillers in d ifferent regions of the United States. As shown, for the northeast, where nuclear power use is highest, and for the west, where hydroelectric power generation is highest, the net g lobal warming impact of vapour-compression chi llers is substantially less than in the east central region, where coal generation dominates. Absorption chillers have a much higher net g lobal warming impact even in that region.

These findings provide an indication for international comparisons. The resul ts from the northeast, based on a comparatively high nuclear power fraction (36% of annual generation), give an ind ication for countr ies with similar (e.g. Finland, Germany, and Spain) and even higher (e.g. Belgium, France, and Taiwan) nuclear shares. The results for the west provide an indication for countries with similar and higher (e.g. Austria, Brazil, Canada, Colombia, Norway, Switze rland, and Venezuela) hydroelectric shares. The east-central region is ind icative of countries w ith high coa l dependence (e.g. Australia, Poland, South Africa, and the United Kingdom).

Global Warming Reduction Figure 3 shows the trend in g lobal warming from low­pressure compression chi llers, projected over ten years from 1985. Thi s demonstrates the effect of improving efficiencies and reduced direct emissions.

Vol. 11 , No. 3, 1993

IEA Heat Pump Centre Newsletter Topical Article

100 ~ 0 Direct - refrigerant

Figure 3: Net globnl wnm1 i11g i111pncts of 11npo11r­co111pressio11 c/Jillers for co11stn11t (1995) ge11emtio11 fuel 111ix n11rf losses.

- D Indirect - electric -~ 80 ~ Ol

,_.,.,...-- .......-- ._.... -c .E (ij

60 :: (ij .D 0 Oi Q)

> 40 >-

~ ro a. E 20 0 0

0 CFC-1 1 R-11 R-123 R-11 R-123

1985 1990 1992

Refrigerant Emissions

Refrigerant losses are much lower in new equipment. For example, one manufacturer has introduced a 'near zero emissions chiller' with annual losses projected at less than 0.5% compared with up to 25% in the past. Much of the earlier losses stemmed from service practices rather than actual leaks. The reduction is achieved by improvements in the construction (e.g. improving gasket materials and fittings), in purge unit performance, in leak testing techniques, and in refrigerant handling and recovery methods. Also significant is the reduction in the amount of refrigerant used in new equipment with the introduction of improved designs, such as the use of highly enhanced heat-exchangers with lower internal volume.

Efficiency

Figure 3 also shows the effect of performance improvement on globa l warming impact. For typical CFC-11 machines, COPs improved from 5.25 to 5.5 (0.67 to 0.64 kW/RT) at standard rating cond itions. A more dramatic improvement appears in the HCFC-123 chillers, since the initial designs were based on equipment optimized for CFC-11 . Figure 3 also reflects the results of further design improvements projected for 1995, by showing global warming emissions from a standard and a high-efficiency HCFC-123 ch iller. Interesting ly, the difference between these two chillers is larger than the d ifferences among the three alternative refrigerants (HCFC-22, HCFC-123 and HFC-1 34a) shown in Figure 1. This comparison clearly shows that once the high-GWP CFCs are eliminated, far greater opportunity exists to reduce globa l warming by efficiency improvement or emission reduction than by refrigerant substitution. Another way to view the result is that the g lobal warming effect from refrigerant emiss ions is equivalent to less than a 0.1 to 1 .1 % change in efficiency (depending

Vol. 11 , No. 3, 1993

- -

R-123 R-123 Standard High efficiency

1995

on refrigerant), once CFCs are eliminated and service and disposal losses are reduced.

Conclusions The study shows that electric vapour-compress ion equipment using HCFC-22, HCFC-123 or HFC-l 34a, offers a better means to minimize the net global warming impact of chillers than does absorption technology. Two mechanisms - reduction of refrigerant emissions and use of high-efficiency equipment - are shown to have far greater benefit than selection among the three alternative refrig erants. Fina lly, the new information presented reaffirm s the finding of prior studies, that regulation of refrigerants based on their GWP, without regard to the commercia lly attainable efficiency of equipment using their alternatives, would increase rather than decrease environmenta l harm.

References:

Calm, J.M., 'Global Warming Impacts of Chillers,' Heating/Piping/Air Conditioning, February 1993.

Calm, J.M., 'Comparative Global Warming Impacts of Electric Vapor-Compression and Direct-Fired Absorption Equipment', Draft Report, Electric Power Research Institute (EPRI), Palo Alto, California, USA, December 7 99 7. (The final report will be available from the EPRI Reports Center - not from the author - by the time this article is published.

Author:

Mr James M. Calm, P.E. Engineering Consultant 7 0887 Woodleaf Lane, Great Falls VA 22066 USA. D

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