27th elementary school of Piraeus enerPHit report

Activity report: Energy performance and climatic conditions in public spaces in the MED area – Retrofitting the 27th Elementary School of Piraeus, Greece according to the Passive House Standard

Deliverable No.

Component No.5-Pilot testing of the methodology, Evaluation and Capitalization

Phase No. 5.6- Final set of applications and Development of a strategic plan to introduce

outcomes in the wider EU area

Contract No.: 1C-MED12-73

Axe2: Protection of the environment and promotion of a sustainable territorial

development

Objective 2.2: Promotion of renewable energy and improvement of energy efficiency

Authors: Municipality of Piraeus ,with the support of ZEB

(S.Pallantzas, Civil Engineer NTUA, Certified Passive House Designer)

Supporting Team: A.Roditi, L.Lymperopoulos, A.Stathopoulou

Submission date: 8/5/2015

Status: Final May 2015

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Contents

1.Building description ................................................................................................................................................... 2

1.1. Building identification data ..................................................................................................................................... 2

1.2. Building operational schedule ................................................................................................................................ 3

1.3. Existing Building data ............................................................................................................................................. 3

1.3.1. Design ............................................................................................................................................................ 3

1.3.2. Building Envelope .......................................................................................................................................... 6

1.3.3. Energy Balance Winter ................................................................................................................................. 13

1.3.5. HVAC- Lightning ........................................................................................................................................... 15

2. The Passive House Standard ........................................................................................................ 17

2.1. Introduction ......................................................................................................................................................... 17

2.2. Passive House Criteria .......................................................................................................................................... 19

2.3. EnerPHit Standard for existing buildings .............................................................................................................. 20

2.4. Occupant Satisfaction........................................................................................................................................... 24

2.6. Boundary conditions for the PHPP calculation ...................................................................................................... 27

2.7. Passive House Standard for Schools ..................................................................................................................... 30

2.7.1. The Air Quality Issue .................................................................................................................................... 30

3. The Enerphit Procedure for the 27th Elementary School .............................................................. 33

3.1. The building envelope .......................................................................................................................................... 33

3.1.1. The opaque elements................................................................................................................................... 34

3.1.2. Transparent Elements .................................................................................................................................. 36

3.2. The new Ventilation System with Heat Recovery.................................................................................................. 39

3.3. Heating and cooling ............................................................................................................................................. 43

3.4. The overall results of the passive house retrofit ................................................................................................... 44

3.4.2. The summer situation (monthly method) .................................................................................................... 45

4. Conclusion .................................................................................................................................... 48

5. How to go about it ....................................................................................................................... 48

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1. Building description

1.1. Building identification data The 27th elementary school in Piraeus is located at 37°57’ N and 23°37’ E. The school consists of two connected

buildings and a courtyard. The building consists of the ground floor, the first and the second floor. The boiler

room is located on the ground floor. The 27th elementary school was built in 1987.

Figure 1-1 depicts the geographical location of the school.

The basic data of the building (according to plans, data provided and on-site measurements) are :

Location Piraeus Climatic Zone (PHPP) GR002a - Athinai

Total Floor area (m2) 1640 Treated Floor Area (PHPP,

m2)

1264

Total Volume (m3) 5014 Conditioned Volume

(PHPP,m3)

4044

Total Thermal Envelope

(PHPP,m2)

2913 Total Windows Area

(PHPP,m2)

335

Number of floors Ground Floor + 2

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1.2. Building operational schedule

The school operates from the 11th of September until the 15th of June from Monday to Friday. During this

period, the school remains closed for approximately 15 days for Christmas holidays and 15 days for Easter

holidays.

The school operates in two shifts. The first shift operates from 08:00 until 14:00. The number of pupils and

teachers in the first shift is 237 and 24 respectively. The second shift operates from 14:00 until 16:15. The

number of pupils and teachers in the second shift is 45 and 2 respectively. In this shift, only two classrooms in

the ground floor are operational.

Each classroom accommodates approximately 20-23 pupils. The main operational characteristics of the 27th

elementary school are:

Occupancy schedule 08:00 – 14:00

14.00 - 16.15

Total number of pupils 237

45

Average occupancy hours 1st shift: 6h

2nd shift: 2h, 15 min

Total number of

teachers & staff

24

1.3. Existing Building data

1.3.1. Design

The whole building is oriented in the north-south direction. The main entrance of the building is on the north

facade. The building envelope has not been renovated since its construction in 1987.

Figure 1-2: North Façade Figure 1-3: South Façade

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The layouts of the ground, first, second floors and the elevations are presented in the Figures 1-4, 1-5, 1-6 , 1-7

and 1-8 respectively.

Figure 1-4 : Ground floor

Figure 1-5: 1st floor

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Figure 1-6: 2nd floor

Figure 1-7: North and East Elevations

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Figure 1-8 : South and West Elevations.

1.3.2. Building Envelope

1.3.2.1. Opaque elements

The construction is a concrete-brick construction. Erker slabs have been used a lot as an architectural feature of

the building. The walls of the school are in a good condition without evident signs of moisture or leakage

problems. According to the plans and the building permission, the walls are built with bricks and are thermally

insulated.

Table 1-1, 1-2 and 1-2 presents the thermal characteristics of the walls as inputted in the PHPP.

Bauteil Nr. Bauteil-Bezeichnung Innendämmung?

01ud Ext.wall_brick

Wärmeübergangsw iderstand [m²K/W]

Ausrichtung des Bauteils 2-Wand innen Rsi 0,13

Angrenzend an 1-Außenluft außen Rsa 0,04

Teilf läche 1 l [W/(mK)] Teilf läche 2 (optional) l [W/(mK)] Teilf läche 3 (optional) l [W/(mK)] Dicke [mm]

Plaster 0,872 20

Brick 0,523 90

Glass wool 0,041 50

Brick 0,523 90

Plaster 0,872 20

Flächenanteil Teilf läche 1 Flächenanteil Teilf läche 2 Flächenanteil Teilf läche 3 Summe

100% 27,0 cm

U-Wert-Zuschlag 0,10 W/(m²K) U-Wert: 0,662 W/(m²K)

7

Concerning these figures, we have increased the U-values by 10% in order to include also all thermal bridges of

the outside walls. We also have decreased proportionally the insulation referring to the concrete elements,

because part of their surface is uninsulated.

Bauteil Nr. Innendämmung?

02ud Ext.wall_conc.





Plaster 0,872 20

Brick 0,523 60

Glass wool 0,041 50

Reinforced concrete 2,030 300

Plaster 0,872 20


70% 30,0% 45,0 cm

0,10 W/(m²K) U-Wert: 2,000 W/(m²K)


03ud Erker slab_


Ausrichtung des Bauteils 0,1 innen Rsi 0,10



Marble tiles 1,100 50


plaster 0,872 20


100% 22,0 cm

0,10 W/(m²K) U-Wert: 3,643 W/(m²K)

8

Figure 1-9: Thermal bridges and uninsulated concrete elements

There are two types of roofs in the school; a flat roof mainly and a sloped roof only in a small part of the school.

Both roof types are thermally insulated. Table 1-4 and Table 1-5 present the thermal characteristics of the roofs.


05ud Flat roof


Ausrichtung des Bauteils 1-Dach innen Rsi 0,17



Plaster 0,870 10

Concrete slab 2,040 150

Light concrete 0,290 100

Cement mortar 1,400 20

Hydroinsulation 0,230 10

Extruded polystyrene 0,034 100

Gravel 2,000 50


100% 44,0 cm

0,10 W/(m²K) U-Wert: 0,373 W/(m²K)

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Figure 1-10: Flat Roof Figure 1-11: Sloped Roof

The floor in contact with the ground is covered by marble tiles and is thermally insulated. Table 1-6 presents the

thermal characteristics of the floor.


06ud Sloped roof





ALUMINIUM SHEET 160,000 5

Insul. Sandwich panel 0,025 100

ALUMINIUM SHEET 160,000 5


100% 11,0 cm

0,10 W/(m²K) U-Wert: 0,338 W/(m²K)

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1.3.2.2. Transparent Elements

There are three types of openings in the building: windows, doors and glass blocks. The windows are double

glazed with aluminum frame and the doors are made of steel. The U value of the windows is 3,7 W/m2K (12 mm

air gap), of the metal doors is 5,8 W/m2K and of the glass blocks is 3,5 W/m2K.

The total area of the building’s openings (including the glass blocks) is approximately 335 m2. The following

Figures depict views of the windows, doors and glass blocks.

Figure 1-12 : Aluminium windows Figure 1-13 : Steel Exterior Doors


04ud Ground Floor slab


Ausrichtung des Bauteils 3-Boden innen Rsi 0,10

Angrenzend an 2-Erdreich außen Rsa 0,00




Glass wool insulation 0,041 50

Sand 0,580 20

Concrete gravel 0,810 200


100% 47,0 cm

0,05 W/(m²K) U-Wert: 0,631 W/(m²K)

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Figure 1-14: Glass blocks Figure 1-15 : Glass blocks and Windows in the South facade

In the following tables one can see the characteristics of the transparent elements, as shown in the PHPP.

1.3.2.3. Shading

The building is situated in a densely built urban area. Big Buildings are shading the school, especially the south

façade. The sloped roof of the Auditorium is blocking a big part of the south façade of the 1st floor. There is no

external shading system for the windows in the building.

Verglasungen Verglasungen

Als Startkomponente für die Optimierung empfohlene Verglasung:

2-fach Wärmeschutzglas (Bitte Behaglichkeitskriterium beachten!)

ID Bezeichnung g-Wert Ug-Wert

W/(m²K)

01ud Existing double glazed windows 0,77 2,90

02ud Glass blocks 0,30 3,50

03ud Existing 5,70

Fensterrahmen Fensterrahmen

Uf-Wert Rahmenbreite Glasrand Wärmebrücke Einbau Wärmebrücke

ID Bezeichnung links rechts unten oben links rechts unten obenYGlasrand

links

YGlasrand

rechts

YGlasrand

unten

YGlasrand

oben

YEinbau

links

YEinbau

rechts

YEinbau

unten

YEinbau

oben

W/(m²K) W/(m²K) W/(m²K) W/(m²K) m m m m W/(mK) W/(mK) W/(mK) W/(mK) W/(mK) W/(mK) W/(mK) W/(mK)

01ud Metal frame not insulated 5,50 5,50 5,50 5,50 0,060 0,060 0,080 0,080 0,030 0,030 0,030 0,030 0,088 0,088 0,088 0,088

02ud Glassblock 0,88 0,88 0,88 0,88 0,001 0,001 0,001 0,001 0,100 0,100 0,100 0,100 0,100 0,100 0,100 0,100

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1.3.2.4. Airtightness

We have assumed in our calculations that the airtightness of the building is very poor, according to experience

from the majority of the existing building stock in Greece.

OrientationGlobal-

RadiationShading

Ver-

schmut-

zung

Non-vertical

RadiationGlass part g-Value Reductionfactor Radiation Window Area

Window

U-ValueGlass area

Average

radiation

Standardwerte → kWh/(m²a) 0,75 0,95 0,85 m2 W/(m2K) m2 kWh/(m2a)

Nord 25 0,56 0,95 0,85 0,75 0,65 0,34 158,39 3,95 118,61 25

Ost 50 0,10 0,95 0,85 0,78 0,77 0,06 13,50 3,68 10,47 50

Süd 95 0,53 0,95 0,85 0,78 0,61 0,33 124,19 3,94 96,63 95

West 49 0,29 0,95 0,85 0,93 0,38 0,22 38,11 3,85 35,35 46

Horizontal 80 1,00 0,95 0,85 0,00 0,00 0,00 0,00 0,00 0,00 80

Summe bzw. Mittelwert über alle Fenster 0,60 0,31 334,18 3,92 261,06

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1.3.3. Energy Balance Winter

According to the envelope characteristics and the airtightness of the building, the energy balance of the building

is shown in the following chart. In the left column the losses of the thermal envelope are shown. The main

problems are: windows, external walls and airtightness of the building. On the right column one can see that

the solar gains are very low. This is the reason why the energy demand, even in winter time, is very high.

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1.3.4. Energy Balance Summer

The following chart shows the temperature situation during summer. As one can see, the inside temperature

(yellow) of the building is often higher than the outside temperature (blue). This happens also during June and

September, when the school is operating.

The energy balance of the Building during summer time is shown in the following chart. The same elements

(walls, roof, windows, lack of airtightness on the left column) lead to heat loads coming inside the building,

while huge internal heat gains (right column white) lead to a large cooling demand.

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1.3.5. HVAC- Lightning 1.3.5.1. Heating / Cooling

The school has a central heating system. The central heating system dates back to the time when the school was

constructed in 1987. In 2004, there was a fuel switch from oil to natural gas by replacing the oil burner with a

natural gas burner. The boiler room is located on the ground floor of the school at the south side of the building.

The central heating system operates for approximately 4 months, from mid-November until the end of March

and the heating schedule daily is from 07.00 to 12.30, 5 days per week. The natural gas fired boiler is

manufactured by the Greek company “Therma”; its total heating capacity is 150.000 kcal/h (175 KW). This boiler

is extremely over-dimensioned, while the needs of the existing building are less than 75 KW.

A two-pipe system is used for hot water circulation throughout the building. The school building is heated by

cast iron radiators. The piping network in the boiler room, but also in the rest of the building, is not insulated. All

areas of the school are heated by radiators, including the circulation areas, except from the WC.

There is not any central cooling system in the school. A few old AC split units, with a total capacity of 26kW, are

located in the teachers’ offices and some other rooms. Some ceiling fans are also present.

Figure 1-16 : The Gas Boiler Figure 1-17 : Uninsulated pipes

Figure 1-18 : Ceiling fans and splits Figure 1-19 : some fans in the Auditorium

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1.3.5.2. Lighting

The school is equipped with T8 fluorescent luminaires of 36 W with a cover. The average power in the

classrooms is approximately 13,5 W/m2 and in the circulating areas is 2,2 W/m2. It is noted that many of the

lighting fixtures are not operating and the lighting conditions are not sufficient.

Figure 1-10 : Insufficient lightning in all areas

Inserting all above data in the PHPP we’ve got the results for the energy consumption of the existing building as

follows:

Comments:

The heating and cooling consumption were expected. The building is mainly uninsulated, the quality of

the windows is very poor and the airtightness is poor. The building has a good orientation but the solar

gains are low because of the surrounding buildings. The indoor air quality is only controlled by opening

the windows, but this causes more energy demand for heating and cooling. Interviews with teachers

gave us information about them not being satisfied from the heating and cooling system and the air

Builiding Energy Consumption according toTFA and Year

Treated Floor Area m² 1263,8 Criteria Ok?

Heating Heating Demand kWh/(m²a) 56 ≤ 15 -

Heating Load W/m² 62 ≤ - -

Cooling Cooling Demand kWh/(m²a) 49 ≤ 15 16

Cooling Load W/m² 42 ≤ - 11

Overheating >25 % - ≤ - -

Humidification G39 (> 12 g/kg) % 0 ≤ 10 ja

Airtightness Blowerdoor Test n50 1/h 7,0 ≤ 1,0 nein

PE-Bedarf kWh/(m²a) 195 ≤ 201,792951 ja

PER-Bedarf kWh/(m²a) 174 ≤ - -

kWh/(m²a) 0 ≥ - -

2 leeres Feld: Daten fehlen; '-': keine Anforderung

Non Renewavble Energy

Renewable

Primary Energy

(PER)Erzeugung erneuerb. Energie

(Bezug auf überbaute Fläche)

-

nein

nein

Aleternative

Criteria

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quality. The final demand is on this level because of the climate conditions and due to the fact that the

school is closed during the hot period of summer.

The Primary Energy demand is lower than expected. This is because the heating system, which has very

high losses due to the uninsulated pipe system, doesn’t work more than 4 hours/day and the lightning

system is very poor. The measured consumptions during the last years are even lower, because of the

financial crisis.

There is a big potential to reduce the energy demand of the school using the passive house standard

and this is what will be analyzed in the following sections.

2. The Passive House Standard

2.1. Introduction

Passive House is a building standard that is truly energy efficient, comfortable and affordable at the same time.

Passive House is not a brand name, but a tried and

true construction concept that can be applied by

anyone, anywhere.

Yet, a Passive House is more than just a low-energy

building:

Passive Houses allow for space heating and cooling

related energy savings of up to 90% compared with

typical building stock and over 75% compared to

average new builds. Passive Houses use less than 1.5

l of oil or 1.5 m3 of gas to heat one square meter of

living space for a year – substantially less than

common “low-energy” buildings. Vast energy

savings have been demonstrated in warm climates

where typical buildings also require active cooling.

Passive Houses make efficient use of the sun,

internal heat sources and heat recovery, rendering conventional heating systems unnecessary throughout even

the coldest of winters. During warmer months, Passive Houses make use of passive cooling techniques such as

strategic shading to keep comfortably cool.

Passive Houses are praised for the high level of comfort they offer. Internal surface temperatures vary little from

indoor air temperatures, even in the face of extreme outdoor temperatures. Special windows and a building

envelope consisting of a highly insulated roof and floor slab as well as highly insulated exterior walls keep the

desired warmth in the house – or undesirable heat out.

A ventilation system imperceptibly supplies constant fresh air, making for superior air quality without

unpleasant draughts. A highly efficient heat recovery unit allows for the heat contained in the exhaust air to be

re-used.

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Typical heating systems in Central Europe, where the Passive House Standard was first developed and applied,

are centralized hot water heating systems consisting of radiators, pipes and central oil or gas boilers. The

average heating load of standard buildings in this area is approximately 100 W/m² (approx. 10 kW for a 100 m²

apartment). The Passive House concept is based on the goal of reducing heat losses to an absolute minimum,

thus rendering large heating systems unnecessary (see image 1). With peak heating loads below 10 W per

square meter of living area, the low remaining heat demand can be delivered via the supply air by a post heating

coil (see box below). A building that does not require any heating system other than post air heating is called a

Passive House; no traditional heating (or cooling) systems are needed.

The Passive House concept itself remains the same for all of the world’s climates, as does the physics behind it.

Yet while Passive House principles remain the same across the world, the details do have to be adapted to the

specific climate at hand. A building fulfilling the Passive House Standard will look much different in Alaska than

in Zimbabwe.

In ‘warm climates’, reducing the space heating demand is a concern but in addition, avoiding overheating in

summer by passive or active cooling strategies become highly relevant for the building optimization. The

improved building envelope of a Passive House helps to minimize external heat loads (solar and transmission).

In addition, well-known shading solutions in warm climates, such as fixed and moveable shading devices (in

order to minimize heat loads), as well as cross night ventilation (passive cooling) are important measures for

Passive Houses.

Regarding summer comfort, the internal heat loads must be minimized e.g. energy efficient appliances should

be focused on.

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First certified Passive Houses in warm climates show the optimization potential in design and execution. While

lower levels of insulation are sufficient for moderate and warm climates such as the majority of the

Mediterranean region, high levels of insulation in opaque elements of the building envelope are required for

extremely hot climates.

To achieve cost-efficient solutions, the resulting insulation thicknesses call for optimized compactness of the

building shape. Windows should meet the comfort and energy requirements, and the designer should be aware

of the high influence of the best orientation.

Very good airtightness is important in all climates, and especially for hot and humid climates [Schnieders et. al.

2012]. Active cooling could be avoided in so-called ‘Happy climates’, but is mandatory for very warm climates

(for instance Granada, Spain).

Ventilation strategies include natural ventilation in summer as well as mechanical ventilation (extract air system

only or ventilation system with heat exchanger and summer bypass). For cost effective Passive Houses in warm

climates component performance should be in the focus of all stakeholders.

2.2. Passive House Criteria

Passive Houses are characterized by an especially high level of indoor comfort with minimum energy

expenditure. In general, the Passive House Standard provides excellent cost-effectiveness particularly in the

case of new builds. The categories Passive House Classic, Plus or Premium can be achieved depending on the

demand and generation of renewable primary energy (PER).

1The criteria and alternative criteria apply for all climates worldwide. The reference area for all limit values is the

treated floor area (TFA) calculated according to the latest version of the PHPP Manual (exceptions: generation

of renewable energy with reference to ground area and airtightness with reference to the net air volume).

2 Two alternative criteria which are enclosed by a double line together may replace both of the adjacent criteria

on the left which are also enclosed by a double line.

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3 The steady-state heating load calculated in the PHPP is applicable. Loads for heating up after temperature

setbacks are not taken into account.

4 Variable limit value subject to climate data, necessary air change rate and internal moisture loads (calculation

in the PHPP).

5 Variable limit value subject to climate data, necessary air change rate and internal heat and moisture loads

(calculation in the PHPP).

6 The steady-state cooling load calculated in the PHPP is applicable. In the case of internal heat gains greater

than 2.1 W/m² the limit value will increase by the difference between the actual internal heat gains and 2.1

W/m².

7 Energy for heating, cooling, dehumidification, DHW, lighting, auxiliary electricity and electrical appliances is

included. The limit value applies for residential buildings and typical educational and administrative buildings. In

case of uses deviating from these, if an extremely high electricity demand occurs then the limit value can also be

exceeded after consultation with the Passive House Institute. Evidence of efficient use of electrical energy is

necessary for this.

8 The requirements for the PER demand and generation of renewable energy were first introduced in 2015. As

an alternative to these two criteria, evidence for the Passive House Classic Standard can continue to be provided

in the transitional phase by proving compliance with the previous requirement for the non-renewable primary

energy demand (PE) of QP ≤ 120 kWh/(m²a). The desired verification method can be selected in the PHPP

worksheet "Verification". The primary energy factor profile 1 in the PHPP should be used by default unless PHI

has specified other national values.

2.3. EnerPHit Standard for existing buildings

The Passive House Standard often cannot be feasibly achieved in older buildings due to various difficulties.

Refurbishment to the EnerPHit Standard using Passive House components for relevant structural elements in

such buildings leads to extensive improvements with respect to thermal comfort, structural integrity, cost-

effectiveness and energy requirements.

The EnerPHit-Standard can be achieved through compliance with the criteria of the component method (Table

2) or alternatively through compliance with the criteria of the energy demand method (Table 3). Only the

criteria of one of these methods must be met. The climate zone to be used for the building's location is

automatically determined on the basis of the chosen climate data set in the Passive House Planning Package

(PHPP).

As a rule, the criteria mentioned in Table 2 correspond with the criteria for certified Passive House components.

The criteria must be complied with at least as an average value for the entire building. A higher value is

permissible in certain areas as long as this is compensated for by means of better thermal protection in other

areas.

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In addition to the criteria in Table 2 or Table 3, the general criteria in Table 4 must always be met. The EnerPHit

categories Classic, Plus or Premium may be achieved depending on the demand and generation of renewable

primary energy (PER).

22

The PHI Low Energy Building Standard is suitable for buildings which do not fully comply with Passive House

criteria for various reasons.

23

Besides a high level of energy efficiency, Passive House buildings and buildings refurbished to the EnerPHit

Standard offer an optimum standard of thermal comfort and a high degree of user satisfaction as well as

protection against condensate related damage. In order to guarantee this, the minimum criteria mentioned

below must also be complied with in addition to the criteria in Sections

Frequency of overheating. Percentage of hours in a given year with indoor temperatures above 25 °C

o without active cooling: ≤ 10 %

o with active cooling: cooling system must be adequately dimensioned

Frequency of excessively high humidity. Percentage of hours in a given year with absolute indoor air

humidity levels above 12 g/kg

o without active cooling: ≤ 20 %

o with active cooling: ≤ 10 %

The criteria for the minimum level of thermal protection according to Table 6 are always applicable irrespective

of the energy standard and must be complied with even if EnerPHit exemptions are used. They apply for each

individual building component on its own (e.g. wall build-up, window, connection detail). Averaging of several

different building components as evidence of compliance with the criteria is not permissible.

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2.4. Occupant Satisfaction o All living areas must have at least one operable window. Exceptions are possible in justifiedcases as long

as there is no significant likelihood of occupant satisfaction being affected.

o It must be possible for the user to operate the lighting and temporary shading elements. Priority must

be given to user-operated control over any automatic regulation.

o In case of active heating and/or cooling, it must be possible for users to regulate the interior

temperature for each utilization unit.

o The heating or air-conditioning technology must be suitably dimensioned in order to ensure the

specified temperatures for heating or cooling under all expected conditions.

o Ventilation system:

o Controllability: The ventilation volume flow rate must be adjustable for the actual demand. In

residential buildings the volume flow rate must be user-adjustable for each accommodation unit

(three settings are recommended: standard volume flow / standard volume flow +30 % /

standard volume flow -30 %).

o Ventilation in all rooms: All rooms within the thermal building envelope must be directly or

indirectly (transferred air) ventilated with a sufficient volume flow rate. This also applies for

rooms which are not continuously used by persons provided that the mechanical ventilation of

these rooms does not involve disproportionately high expenditure.

o Excessively low relative indoor air humidity : If a relative indoor air humidity lower than 30 % is

shown in the PHPP for one or several months, effective countermeasures should be undertaken

(e.g. moisture recovery, air humidifiers, automatic control based on the demand or zone,

extended cascade ventilation, or monitoring of the actual relative air humidity with the option

of subsequent measures).

o Sound level: The ventilation system must not generate noise in living areas. Recommended

values for the sound level are ≤ 25 db(A): supply air rooms in residential buildings, and

bedrooms and recreational rooms in non-residential buildings ≤ 30 db(A): rooms in non-

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residential buildings (except for bedrooms and recreational rooms) and extract air rooms in

residential buildings

o Draughts: The ventilation system must not cause uncomfortable draughts.

2.5. The Passive House Planning Package (PHPP)

The Passive House Planning Package (PHPP) (order here) contains everything necessary for designing a properly

functioning Passive House. The PHPP prepares an energy balance and calculates the annual energy demand of

the building based on the user input relating to the building's characteristics.

The main results provided by this software programme include:

o The annual heating demand [kWh/(m²a)] and maximum heating load [W/m²]

o Summer thermal comfort with active cooling: annual cooling demand [kWh/(m²a)] and maximum

cooling load [W/m²]

o Summer thermal comfort with passive cooling: frequency of overheating events [%]

o Annual primary energy demand for the whole building [kWh/(m²a)]

The PHPP consists of a software program and a printed manual. The manual not only elucidates the calculation

methods used in the PHPP but also explains other important key points in the construction of Passive Houses.

The actual PHPP program is based on Excel (or an equivalent spreadsheet software programme) with different

worksheets containing the respective inputs and calculations for various areas. Among other things, the PHPP

deals with the following aspects:

o Dimensioning of individual components (building component assemblies including U-value calculation,

quality of windows, shading, ventilation etc.) and their influence on the energy balance of the building in

winter as well as in summer

o Dimensioning of the heating load and cooling load

o Dimensioning of the mechanical systems for the entire building: heating, cooling, hot water provision

o Verification of the energy efficiency of the building concept in its entirety

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The calculations are instantaneous, i.e. after changing an entry the user can immediately see the effect on the

energy balance of the building. This makes it possible to compare components of different qualities without

great effort and thus optimize the specific construction project - whether a new construction or a refurbishment

- in a step-by-step manner with reference to energy efficiency. Typical monthly climatic conditions for the

building location are selected as the underlying boundary conditions (particularly temperature and solar

radiation). Based on this, the PHPP calculates a monthly heating or cooling demand for the entered building. The

PHPP can thus be used for different climatic regions around the world.

All calculations in the PHPP are based strictly on the laws of physics. Wherever possible, specific algorithms

resort to current international standards. Generalisations are necessary in some places (e.g. global established

routines for shading), and sometimes deviations may also be necessary (due to the extremely low energy

demand of Passive Houses, e.g. for the asymptotic formula for the utilisation factor), while for some areas there

are no internationally relevant standards (e.g. with reference to dimensioning of ventilation systems). This

approach has resulted in an internationally reliable calculation tool with which the efficiency of a construction

project can be evaluated more accurately than with conventional calculation methods. (Read more about this in

the section PHPP - validated and proven in practice)

The PHPP forms the basis for quality assurance and certification of a building as a Passive House or an EnerPHit

retrofit. The results of the PHPP calculation are collated in a well-structured verification sheet. In addition to the

basic components of the PHPP already mentioned, various useful additions have also been made for the user's

benefit. For example, the simplified calculation method based on the German energy saving ordinance EnEV has

been integrated into the PHPP. Preparing an energy performance certificate for a project is facilitated by an

additional tool.

A section of the PHPP “Verification”-sheet with the results for a sample detached house built to the Passive

House Standard.

27

On this clearly arranged flow chart you can see how the PHPP works

The PHPP can be used all over the world and is now available in several languages. Some of the translated

versions contain additional calculations based on regional standards (similar to the German EnEV) in order to

allow use as official verification of energy efficiency in the respective countries.

The first edition of the Passive House Planning Package (PHPP) was released in 1998 and has been continuously

further developed since then. New modules which were important for planning were added later on, including

advanced calculations for window parameters, shading, heating load and summer behaviour, cooling and

dehumidification demands, cooling load, ventilation for large objects and non-residential buildings, taking into

account of renewable energy sources and refurbishment of existing buildings (EnerPHit). The PHPP is

continuously being validated and expanded in line with measured values and new findings.

The new PHPP 9 (2015) was launched at the 19th International Passive House Conference in April 2015.

2.6. Boundary conditions for the PHPP calculation

When verifying the criteria using the Passive House Planning Package (PHPP), the following boundary conditions

must be fulfilled:

28

2.6.1. Zoning

The entire building envelope (e.g. a row of terraced houses or an apartment block or office building with several

thermally connected units) must be taken into account for calculation of the specific values. An overall

calculation can be used to provide evidence of this. If all zones have the same set temperature, then a weighted

average based on the TFA from individual PHPP calculations of several sub-zones may be used. Combination of

thermally separated buildings is not permissible. For the certification of refurbishments or extensions, the area

considered must contain at least one external wall, a roof surface and a floor slab or basement ceiling. Single

units inside a multi-storey building cannot be certified. Buildings which are adjacent to other buildings (e.g.

urban developments) must include at least one exterior wall, a roof area and a floor slab and/or basement

ceiling to be eligible for separate certification.

2.6.2. Calculation method

The monthly method is used for the specific heating demand.

2.6.3. Internal heat gains

The PHPP contains standard values for internal heat gains in a range of utilization types. These are to be used

unless PHI has specified other values (e.g. national values). The use of the individually calculated internal heat

gains in PHPP is only permitted if it can be shown that actual utilisation will and must differ considerably from

the utilisation on which the standard values are based.

2.6.4. Internal moisture gains

Average value over all annual hours (also outside of the usage period): residential building: 100 g/(person*h)

non-residential building without significant moisture sources beyond moisture released by persons (e.g. office,

educational buildings etc.): 10 g/(Person*h) non-residential building with significant moisture sources beyond

moisture released by persons: plausible substantiated estimation based on the anticipated utilisation.

2.6.5. Occupancy rates

Residential buildings: standard occupancy rate in the PHPP; if the expected number of persons is significantly

higher than the standard occupancy rate, then it is recommended that the higher value should be used. Non-

residential buildings: Occupancy rates and periods of occupancy must be determined on a project-specific basis

and coordinated with the utilization profile.

2.6.6. Indoor design temperature

Heating, residential buildings: 20 °C without night setback, non-residential buildings: standard indoor

temperatures based on EN 12831 apply. For unspecified uses or deviating requirements, the indoor

temperature is to be determined on a project-specific basis. For intermittent heating (night setback), the indoor

design temperature may be decreased upon verification. Cooling and dehumidification: 25 °C for 12 g/kg

absolute indoor air humidity

29

2.6.7. Climate data

Climate data sets (with a seven-digit ID number) approved by the Passive House Institute should be used. The

selected data set must be representative for the climate of the building's location. If an approved data set is not

yet available for the location of the building, then a new data set can be requested from an accredited Passive

House Building Certifier.

2.6.8. Average ventilation volumetric flow

Residential buildings: 20-30 m³/h per person in the household, but at least a 0.30-fold air change with reference

to the treated floor area multiplied by 2.5 m room height. Non-residential buildings: The average ventilation

volumetric flow must be determined for the specific project based on a fresh air demand of 15-30 m³/h per

person (higher volumetric flows are permitted in the case of use for sports etc. and if required by the applicable

mandatory requirements relating to labour laws). The different operation settings and times of the ventilation

system must be considered. Operating times for pre-ventilation and post-ventilation should be taken into

account when switching off the ventilation system. For residential and non-residential buildings, the mass flows

used must correspond with the actual adjusted values.

2.6.9. Domestic hot water demand

Residential buildings: 25 litres of 60 °C water per person per day unless PHI has specified other national values.

Non-residential buildings: the domestic hot water demand in litres of 60 °C water per person per day must be

separately determined for each specific project.

2.6.10. Balance boundary for electricity demand

All electricity uses that are within the thermal building envelope are taken into account in the energy balance.

Electricity uses near the building or on the premises that are outside of the thermal envelope are generally not

taken into account. By way of exception, the following electricity uses are taken into account even if they are

outside of the thermal envelope:

o Electricity for the generation and distribution of heating, domestic hot water and cooling as well as for

ventilation, provided that this supplies building parts situated within the thermal envelope.

o Elevators and escalators which are situated outside provided that these overcome the distance in height

caused by the building and serve as access to the building

o Computers and communication technology (server including UPS, telephone system etc.) including the

air conditioning necessary for these, to the extent they are used by the building's occupants.

o Household appliances such as washing machines, dryers, refrigerators , freezers if used by the building's

occupants themselves

o Intentional illumination of the interior by externally situated light sources.

30

2.7. Passive House Standard for Schools

The Passive House concept has been

undergoing a rapid expansion in the last few

years, also in the non-residential sector.

Administrative buildings, factory buildings,

community centers and many other buildings

have been realized. Some initial projects have

also been realized in the area of new school

construction and school modernization. The

systematically examined boundary conditions

for the construction of schools were published

in 2006 within the framework of the Protocol

Volume “Passive House Schools” in the

“Research Group for Cost-efficient Passive

Houses” [Feist 2006] . Experiences with initial

projects that have been realized were also

incorporated into this.

2.7.1. The Air Quality Issue

The pollution of the indoor air in schools consists mainly of the following:

o Outdoor air pollution

o Metabolic waste products of the occupants

o Emissions from building materials, furnishings and work equipment (crafts, chemistry)

o Radon pollution

o Microorganisms (MVOC)

2.7.2 The Requirements

o Each modern school should have

controlled ventilation which meets the criteria

for acceptable indoor air quality.

o In the interest of a justified investment or

technical expenditure, the air flow rates of the

school's ventilation system should be based on

health and educational objectives and not on

the upper limits of the comfort criteria. The

31

result is: CO2 limit values between 1200 and 1500 ppm and designed air flow rates between 15 and 20

m³/person/h (possibly more for a higher average age of the pupils).

With these reference values, the result is a significant improvement in the air quality in comparison with

the values usually obtained in Germany, Austria and Switzerland today. Experience with the Passive

Houses already built also shows that the designed values should not be reduced even further. For

increased air quantities attention would have to be paid to the resulting reduction in the relative air

humidity in winter. If the per person air flow rates are projected as 15 to 20 m³/(h pers) in the given

interval, the primary objectives of indoor air quality will certainly be achieved and the problem of low

relative humidity does not even arise.

In comparison with residential buildings and office buildings, the overall air flow rates and air change

rates which have to be planned are considerably higher during use due to the increased number of

persons present in schools.

o In the interest of justifiable operational costs, the ventilation systems in schools must be operated

periodically or according to demand. Preliminary purge

phases or subsequent purging periods ensue before and

after use for hygiene reasons. The easiest solution is to use

time control.

A direct result of the designed high air change rates is that

the operating times of the ventilation system have to be

restricted to the periods of use or the air quantities should

at least be greatly reduced outside of these times, because

otherwise there will be very high electricity consumption

values even for efficient systems – this differs

fundamentally from home ventilation in which the designed air quantities are near those required for

basic ventilation needed on a permanent basis (with 0.25 h-1).

In schools, for basic ventilation planned with 2 h-1, there are several possibilities, the most efficient

being a one-hour preliminary purge phase with designed volumetric air flows, with which the necessary

”double” exchange of the air volume can be achieved. After that, regulation of the air quantities

according to demand should be strived for, on which the occupancy density, the CO2 content of the air

or other representative air quality indicator can be based.

Without any ventilation, the air quality is poor. The CO2 concentration can be easily measured; and is

correlated to other indoor pollution substances e.g. Radon. With a ventilation system, all pollution is

reduced to a hygienically satisfactory level (subjectively, visitors note that “it doesn't smell like a school

here at all”).

As shown by experience, it should be ensured that the technology used is robust and simple and, if

necessary, possible to operate manually (no “technological Christmas trees”). For intermittent operation

of the ventilation system, it is important that all system parts, especially the filters, are “run dry” before

switching off the air flows – this is achieved most easily by using the recirculation mode after the period

of use.

32

o Passive House schools should be designed so that besides the usual heating using supply air, it is also

possible to heat up the rooms to a comfortable level during the preliminary purge phase in the

morning. It is stated that heating classrooms using the supply air in schools is no problem because the

volumetric fresh air flow based on the useable area is very high. However, after the setback phase,

reheating to a comfortable level (particularly in relation to the radiation temperature asymmetry) is only

possible if the building's envelope surfaces have a high level of thermal protection. For schools this is

the decisive criterion.

Parametric studies with thermal simulation of school buildings show that under the given conditions the

level of thermal protection complying with the “residential Passive House Standard” is within the range

of optimum results. Nevertheless, for school buildings there is more scope than there is for residential

buildings, due to the many kinds of regulation possibilities and the high air changes available. Because

the buildings are generally comparatively large and compact, the designer is well-advised to approach

the optimum level by complying with the classic Passive House Standard while at the same keeping a

safety margin.

o The criteria given above can be met if, under the boundary conditions of use, the building envelope

and heat recovery are designed so that the annual heating demand according to the PHPP is less than

or equal to 15 kWh/(m²a) (based on the total net useable area).

A detailed analysis has confirmed the planning guidelines according to which some Passive House

schools had already been planned and built. This was by no means self-evident, as, due to the

completely different usage, this criterion is derived in a completely different way than the criterion

which applies to residential buildings.

Nevertheless, it is no coincident that this result is quantitatively comparable with that of the Passive

House residential building; the reason for this is that the temporal average values of the boundary

conditions (air quantities, internal heat sources, heat load) are very similar to those for residential use.

As shown by the examples of buildings which have already been built, applying these basic

recommendations and the components available on the market today, it is possible to realise Passive

House school buildings with various design concepts.

School refurbishment with Passive House components can be planned using the PHPP and that, except

for some clearly defined features, the same focal points had to be taken into consideration for these as

for residential or office buildings in the Passive House Standard.

An important boundary condition is the intermittent use with temporarily extremely high internal loads.

The temporal average value of the internal loads with 2.8 W/m² on average is not much more than the

values for residential use. Setback phases play an important role in school buildings. A tool is available

for determining the expected effective temperature reduction [PHPP 2007] .

In school buildings particular attention should be paid to specific use in summer. Sufficient shading,

night-time ventilation and high internal heat capacity are all imperatives. If it is not possible to meet one

33

of these requirements, equivalent compensation must be provided – this can be concrete core

temperature control or the use of adequate heat exchangers, for example.

For reheating after setback phases, the central heating generator must be able to provide a sufficiently

high output (in the range of 50 W/m² of heated useable area). The pre-heating phase must be regulated

via time control and internal temperature measurement.

Based on all previous experiences, the Passive House concept has proved to be just as successful for

schools, where it is particularly advantageous due to the ventilation system’s importance.

3. The Enerphit Procedure for the 27th Elementary School

Passive House school buildings are particularly interesting. Several school buildings have been realized

using this standard and experiences gained from their use are now available: The Passive House

Standards allows for energy savings of around 75% in comparison with average new school buildings -

and of course there is no need for an additional heating or cooling system. The additional investment

costs are within reasonable limits. What is important is the know-how - which can be obtained by every

architect thanks to the “Passive House Schools” Protocol Volume, funded by the Hessian Ministry of

Economic Affairs.

In our calculations we have implemented the following steps:

3.1. The building envelope

The most important principle for energy efficient construction is a

continuous insulating envelope all around the building (yellow

thick line), which minimizes heat losses like a warm coat.

In addition to the insulating envelope there should also be an

airtight layer (red line) as most insulation materials are not airtight.

Preventing thermal bridges (circles) is essential – here an individual

planning method has to be developed, according to the

construction and used materials, in order to achieve thermal

bridge free design. Independently of the construction, materials or building technology, one rule is

always applicable: both insulation and airtight layers need to be continuous.

34

3.1.1. The opaque elements

Applying exterior wall insulation to

an existing building when the plaster

needs to be renewed can help

reduce the costs for the plaster

significantly as plastering can be

limited to rough filling where the old

plaster is no longer able to bear

loads and needs to be chipped off.

There is no universal answer to the

question whether a compound

insulation system needs to be

bonded to the old plaster or even

dowelled. Manufacturers are starting

to offer strength tests for larger projects in order to determine whether the old plaster is still able to

bear loads. Additional dowelling may be dispensed with if such guarantees are provided by

manufacturers.

In our case we have added a 100mm external insulation layer (for example EPS 035) to all external walls

of the building (except from the eastern partition wall towards the neighboring building). The U-Value

of the external walls was improved as follows:


08ud Ext.wall_brick_eps





Plaster 0,872 20

Brick 0,523 90

Glass wool 0,041 50

Brick 0,523 90

Plaster 0,872 20

eps 0,035 100

Acrylic plaster 0,350 4


100% 37,4 cm

W/(m²K) U-Wert: 0,215 W/(m²K)

35

In the flat roof of the building we have added 100 mm of XPS 034


09ud Ext.wall_conc._eps





Plaster 0,872 20

Brick 0,523 60

Glass wool 0,041 50


Plaster 0,872 20

eps 0,035 100



70% 30,0% 55,4 cm

W/(m²K) U-Wert: 0,286 W/(m²K)


10ud Erker slab_eps


Ausrichtung des Bauteils 0,1 innen Rsi 0,10





plaster 0,872 20

eps 0,035 100



100% 32,4 cm

W/(m²K) U-Wert: 0,317 W/(m²K)

36

There is no need to put additional insulation on the sloped roof of the Auditorium. There is also no need

to put insulation on the ground floor slab, because the thermal bridges to the ground are not so

important.

3.1.2. Transparent Elements

In new buildings, as well as in old buildings that have not been modernized, windows constitute a weak

point in terms of thermal protection as their thermal transmittance (heat transfer coefficient, U-value) is

generally much poorer than that of the wall, roof or floor constructions. As a rule, windows of old

buildings also have massive leaks which lead to high heat losses and to an impairment of comfort due to

drafts, and they can also cause building damage. On the other hand, windows are essential in providing

solar gains and thus reducing the overall heating demand.

One of the objectives of carrying out modernizations is to provide a comfortable indoor temperature for

the occupants. Half our perception of warmth is from the radiant temperature of our surroundings and

the other half from the air temperature. It will feel cold next to internal surfaces that are cold even if the

air temperature is normal just from the lack of radiant heat. So for comfort it is important that cold

internal surface temperatures are avoided as well as draughts and temperature stratification in the

room.

In this context it is important to limit the difference between the operative or perceived indoor

temperature and the temperature of the individual surfaces enclosing the room volume (walls, ceiling,


05ud Flat roof_eps





Plaster 0,870 10

Concrete slab 2,040 150

Light concrete 0,290 100

Cement mortar 1,400 20

Hydroinsulation 0,230 10

Extruded polystyrene 0,034 200

Gravel 2,000 50


100% 54,0 cm

W/(m²K) U-Wert: 0,151 W/(m²K)

37

floor or windows). As long as the operative temperature also remains within the comfortable range

unpleasant temperature differences between surfaces and uncomfortable radiant heat effects are

avoided. Limiting the temperature difference also reduces the effect of cold air descending from cold

surfaces producing draughts and cold feet.

In the relevant literature, e.g. [Feist 1998] , it is stated that as soon as the temperature of individual

surfaces that enclose the room volume does not exceed a limit of 4.2 K below the operative

temperature of the room, the unpleasant effects mentioned above can no longer occur.

Thus the comfort requirement is: θsi ≥ θop – 4.2 K

If the operative indoor temperature θop is assumed to be 22°C and the external temperature θa is –

16°C, for an internal heat transfer resistance Rsi = 0.13 m²K/W, the result is the well-known Passive

House comfort criterion Uw,installed ≤ 0.85 W/(m²K) which was introduced more than a decade ago.

If it is not possible to achieve this value, a heat source must be provided underneath the window in

order to prevent uncomfortable cold air descent and radiant heat deprivation, and to achieve the

desired level of comfort.

The heat transfer coefficient for the installed window is determined based on the U-values of the glazing

(Ug) and the frame (Uf) as well as the thermal bridge loss coefficient of the glazing edge (Ψg), the

connection of the adjacent building components (ΨInstall) and the respective areas or lengths:

All these values are required for the correct consideration of the heat losses of a window in the energy

balance.

For the overall concept, not only the heat losses but also the solar gains through the windows are

important. Besides the orientation and shading of the windows, the total solar transmission factor of

the glass and the frame proportion also influence the solar gains. Since significant energy gains cannot

be achieved through the opaque frames, it is important to minimize the frame proportions (smaller

facing widths, large windows, no glazing bars, fewer glazing sections). The total solar transmission factor

g refers to the proportion of incident solar radiation which enters the building. If the g-value is 0.3 or

30%, for example, this means that 30% of the solar radiation incident on the glass pane can reach the

inside of the building. Modern standard triple-glazing has g-values of around 50%. G-values of up to 60%

are possible at moderate additional costs with the use of one or more panes made of clear glass instead

of float glass. The g-value is lower if there are special requirements in terms of the robustness of the

glass or fire protection regulations. This should be taken into consideration for the energy balance at an

early stage. In moderate climates, glass with lower g-values (solar protection glass) should only be used

if very high internal heat loads are expected.

38

OrientationGlobal

RadiationShadings Dirty

Non vertical

radiationGlass area g-Value Reduction Factor Radiation Window area Uw Glass area

average

global

radiation

Standardwerte → kWh/(m²a) 0,75 0,95 0,85 m2 W/(m2K) m2 kWh/(m2a)

Nord 25 0,50 0,95 0,85 0,54 0,65 0,22 158,39 1,34 85,93 25

Ost 50 0,10 0,95 0,85 0,59 0,40 0,05 13,50 1,32 8,03 50

Süd 95 0,46 0,95 0,85 0,58 0,40 0,21 124,19 1,35 71,52 95

West 49 0,32 0,95 0,85 0,71 0,54 0,19 38,11 1,35 27,12 46

Horizontal 80 1,00 0,95 0,85 0,00 0,00 0,00 0,00 0,00 0,00 80

Summe bzw. Mittelwert über alle Fenster 0,53 0,21 334,18 1,34 192,60

In our building, windows are the main reason for the heat losses. So they have to be replaced with

better, thermal protected components. We have chosen the following values for the new components:

South oriented double-glazed windows with Ug=1.30 W/m2K, g-Value 0.40 and Uf=1.00 W/m2K

North oriented double-glazed windows with Ug=1.30 W/m2K, g-Value 0.60 and Uf=1.00 W/m2K

The east and west windows have the same values as the south oriented.

All glass blocks will be replaced by double-glazed windows

Shading of the south-east-west windows will be improved by 75% during summer

The installation of the new windows will minimize the installation thermal bridges and improve their

airtightness.

39

The steel external doors of the building will also be replaced

by new with similar Uw values. The new doors have to be

double in order to improve the needed airtightness.

3.2. The new Ventilation System with Heat Recovery.

Ventilation with heat recovery is a central requirement for the operation of Passive Houses. The

significant reduction in ventilation heat losses as a result of the heat recovery makes it possible to both

simplify and reduce the size of the heating system, thereby reducing investment costs as well.

Ventilation with heat recovery plays an important role in energetic refurbishment as well. Significant

cost and energy savings due to the lower ventilation heat losses combined with the resulting good

indoor air quality make such ventilation not only more attractive, but necessary for energy efficient

construction.

Next to climatic conditions and the required ventilation rate, a building’s ventilation heat losses mainly

depend on:

the heat recovery efficiency of the ventilation unit

the airtightness of the building (the free infiltration and exfiltration)

the forced infiltration and exfiltration caused by the volume flow balancing between exhaust

and fresh air

Beside the heat recovery of the ventilation unit and the airtightness of the building, the volume flow

balancing of exhaust air and fresh air also has an important influence on ventilation heat losses and,

therefore, on the energy balance of the whole building. Imbalances can be caused e.g. by improper

commissioning of the ventilation system or gradual clogging of the air filter.

In our case we have designed a simple ventilation system consisting of two main duct systems in each

level, one for the supply air into the north oriented classes and offices and one for the extract air from

the south oriented floors and sanitary rooms.

40

Ground floor: the heat recovery unit is located in the former oil-tank room.

1st floor: Supply air goes to the classrooms, extract air comes from the corridors (the temperature there

is higher because of their south orientation) and the WC’s.

41

2nd floor : same design as in 1st floor.

The supply air volume is in general 18m3/h per person, so every classroom needs approximately

430m3/h. The total capacity of the central unit is 5.000 m3/h. The heat recovery rate has to be >75%.

There are certified units with a rate of 85% in the market.

A ground heat exchanger, developed under the school yard, will support the ventilation system and will adjust

the air temperature and humidity during the whole year. Ground-air heat exchangers (also known as earth

tubes) offer an innovative method of heating and cooling a building and are often used on zero carbon /

Passivhaus buildings. The ventilation air is simply drawn through underground pipes at a depth of 1.5m into the

HRV, which pre-heats the air in the winter and pre-cools the air in the summer. So the Heat Recovery Rate will

be as follows:

42

The Ventilation unit will have an automatic summer by-pass and an electrical heating registry. The unit will

operate 24h/day: 8 hours in full operation, 2 hours before the school opens at 77% and during the night at 40%.

The average ventilation volume will be 2.952 m3/h and the average air exchange will be 0.73 ach/h. The unit will

not operate during weekends and vacations. Preheating the air flow up to 38 Degrees Celsius will cover all the

heating demand of the building. It is proposed to use the existing conventional heating system of the building

every morning of a working day for an hour before the school opens. For the rest of the day the ventilation

system will cover the needs.

During summer the ventilation rate will increase by 50%. Night ventilation

trough automatic opened windows will decrease the needs for cooling.

Auswahl des Lüftungsgeräts mit Wärmerückgewinnung

Aufstellort Lüftungsgerät

Wärmebereit- Rückfeuchtzahl spez. Leistungs- Einsatzbereich Frostschutz

zur Lüftungsgeräte-Liste stellungsgrad aufnahme erforderlich

Sortierung: WIE LISTE Gerät hWRG hFRG [Wh/m³] [m³/h]

Auswahl Lüftungsgerät 0,84 0,00 0,45 1300 - 5200 ja

Ausführung Frostschutz 1-Nein

Leitwert Außenluftkanal Y W/(mK) 0,169 Grenztemperatur [°C] 2

Länge des Außenluftkanals m 5 Nutzenergie [kWh/a] 0

Leitwert Fortluftkanal Y W/(mK) 0,169

Länge des Fortluftkanals m 5 Innenraumtemperatur (°C) 20

Temperatur des Aufstellraumes °C 20 mittl. Außentemp. Heizp. (°C) 12,9

(nur eintragen falls Gerät außerhalb der thermischen Hülle) mittl. Erdreichtemp. (°C) 20,7

Effektiver Wärmebereitstellungsgrad hWRG,ef f 83,9%

Effektiver Wärmebereitstellungsgrad Erdreichwärmeübertrager

Wirkungsgrad Erdreichwärmeübertrager h*EWÜ 85%

Wärmebereitstellungsgrad EWÜ hEWÜ 94%

0654vl03-LÜFTA - MAXK I3 6000 DC

1-Innerhalb therm.Hülle

Betriebsarten tägl. Betriebszeiten Maximum Luftvolumenstrom Luftwechsel

h/d m³/h 1/h

Maximum 8,0 1,00 4680 1,16

Standard 2,0 0,77 3600 0,89

Grundlüftung 0,54 2520 0,62

Minimum 14,0 0,40 1872 0,46

mittlerer Luftaustausch (m³/h) mittlerer Luftwechsel (1/h)

Mittelwert 0,63 2952 0,73

PV - PG = 16974 bzw. 15383

Heizwärmelast PH = 16974 W

Flächenspezifische Heizwärmelast PH / AEB = 13,4 W/m²

Eingabe max. Zulufttemperatur 38 °C °C °C

Max. Zulufttemperatur Jzu,Max 38 °C Zulufttemperatur ohne Nachheizung Jzu,Min 19,7 19,8

zum Vergleich: Wärmelast, die von der Zuluft transportierbar ist PZuluft;Max = 17826 W spezifisch: 14,1 W/m²

(ja/nein)

Über die Zuluft beheizbar? ja

43

3.3. Heating and cooling

The existing heating system will be

used only for the pre-heating of the

building every day before the school

opens and after longer periods, when

the school is closed. This will decrease

the gas consumption by 80%. In order

to improve the performance of the

system, the pipe system has to be well

insulated.

The building will need 4.500 KWh/a for

heating.

For the summer situation the split units that exist, will cover the needs of the building. It is proposed to put

these units on the corridors of each Level and the ventilation system will supply the fresh air in all rooms. 20Kw

of air-conditioning power will cover the whole building. The building will need 11.500 KWh/a for cooling.

44

3.4. The overall results of the passive house retrofit

With the implementation of the above described specifications and according to the calculations with the

Passive House Planning Package PHPP ver.9.1/2015 the new energy balances of the building will be as following:

3.4.1. The winter situation (monthly method)

The losses of the external walls (light blue), the windows (yellow) and the airtightness on the left column are

extremely decreased. The losses are more balanced now. There are no losses to the ground. On the other hand

the solar gains (yellow) on the right column are still not big enough. A further improvement for the solar gains

could be to install horizontal windows on the existing south oriented sloped roof. The heating energy demand is

decreased by 85%.

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3.4.2. The summer situation (monthly method)

The additional ventilation with the by-pass control and the night ventilation through the windows is very

important for reducing the risk of overheating. The mechanical ventilation should be decreased during the

summer period by 50% and the night ventilation should add 0,50 ACH/h.

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Below is the new energy balance of the building according to PHPP calculations:

EnerPHit-NachweisFoto oder Zeichnung Objekt:

Straße:

PLZ/Ort:

Provinz/Land

Objekt-Typ:

Klimadatensatz: ud---02-Athinai-Piraeus

Klimazone: 5: Warm Standorthöhe: 50 m

Bauherrschaft:

Straße:

PLZ/Ort:

Provinz/Land

Architektur: Haustechnik:

Straße: Straße:

PLZ/Ort PLZ/Ort:

Provinz/Land Provinz/Land

Energieberatung: Zertfizierung:

Straße: Straße:

PLZ/Ort: 15234 PLZ/Ort:

Provinz/Land Provinz/Land

Baujahr: 1987 Innentemperatur Winter [°C] 20,0 Innentemp. Sommer [°C]: 25,0

Zahl WE: 1 Interne Wärmequellen (IWQ) Heizfall [W/m2]: 2,8 IWQ Kühlfall [W/m²]: 2,8

Personenzahl: 260,0 spez. Kapazität [Wh/K pro m² EBF]: 204 Mechanische Kühlung: x

Gebäudekennwerte mit Bezug auf Energiebezugsfläche und Jahr

Energiebezugsfläche m² 1263,8 Kriterien Erfüllt?2

Heizen Heizwärmebedarf kWh/(m²a) 4 ≤ 15 -

Heizlast W/m² 13 ≤ - -

Kühlen Kühl- + Entfeuchtungsbedarf kWh/(m²a) 9 ≤ 15 16

Kühllast W/m² 12 ≤ - 11

Übertemperaturhäufigkeit (> 25 °C) % - ≤ - -

Häufigkeit überhöhter Feuchte (> 12 g/kg) % 0 ≤ 10 ja

Luftdichtheit Drucktest-Luftwechsel n50 1/h 1,0 ≤ 1,0 ja

PE-Bedarf kWh/(m²a) 76 ≤ - -

PER-Bedarf kWh/(m²a) 25 ≤ 45 30

kWh/(m²a) 57 ≥ 60 36

2 leeres Feld: Daten fehlen; '-': keine Anforderung

EnerPHit Plus? ja

Stefanos Pallantzas

ja

ja

alternative

Kriterien

GR-Griechenland

27th Elementary School of Piraeus

Attiki

Municipality of Piraeus

GR-Griechenland

School

Iraklidon 15B

Chalandri

Attiki

GR-GriechenlandAttiki

Ich bestätige, dass die hier angegebenen Werte nach dem Verfahren PHPP auf Basis der Kennwerte

des Gebäudes ermittelt wurden. Die Berechnungen mit dem PHPP liegen diesem Nachweis bei.

ja

Nicht erneuerbare

Primärenergie (PE)

Erneuerbare

Primärenergie

(PER)Erzeugung erneuerb. Energie

(Bezug auf überbaute Fläche)

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According to these results the building is a Passive House Plus Building. The heating demand is now 4KWh/m2a,

decreased by 93% and the cooling demand is 9KWh/m2a, decreased by 82%. These results cover the passive

house criteria for our climatic region (<15 KWh/m2a for heating or cooling).

The loads for heating and cooling are 13W/m2 and 12W/m2, 10 times lower than these of the conventional

buildings.

The Primary Energy Demand (PE) is 76KWh/m2a, fulfills the 120KWh/m2a criteria. Also following the new PER

criteria of Primary Renewable Energy the criteria are fulfilled.

Furthermore, if we install a 160m2 Photovoltaic System on the south roofs of the building, the building will

produce on average over 45.000 Kwh of electricity every year, a factor which will make the building a PLUS

passive house, a building that produces the energy it needs.

Anlagenbezeichnung Anlage 1 Anlage 2 Anlage 3 Anlage 4 Anlage 5 PV-Referenzanlage

Standort: Auswahl aus dem Blatt Flächen 3-SLOPED_ROOF 54-2f_ROOF_SLAB

Größe der ausgewählten Fläche 126,4 505,9 m²

Abweichung zur Nordrichtung 180 0 °

Neigung gegen die Horizontale 13 0 °

Alternative Eingabe: Abweichung zur Nordrichtung °

Alternative Eingabe: Neigung gegen die Horizontale °

Angaben aus dem Moduldatenblatt

Technologie 4-Mono-Si 5-Poly-Si 5-Poly-Si 5-Poly-Si 5-Poly-Si 4-Mono-Si

Nennstrom IMPP0 7,71 7,71 7,71 A

Nennspannung UMPP0 30,50 30,50 30,50 V

Nennleistung Pn 235 235 0 0 0 235 Wp

Temperaturkoeffizient des Kurzschlussstroms a 0,040 0,040 0,040 %/K

Temperaturkoeffizient der Leerlaufspannung b -0,340 -0,340 -0,340 %/K

Modulabmessssungen: Höhe 1,658 1,658 1,658 m

Modulabmessungen: Breite 0,994 0,994 0,994 m

1,6 Modulfläche [m²]

Weitere Angaben

Modulanzahl nM 50 50 0,0

Höhe des Modulfelds 1,0 1,0 m

Höhe des Horizonts hHori 0,0 0,0 m

Horizontentfernung aHori 15,0 15,0 m

zusätzlicher Abminderungsfaktor Verschattung rso

Wirkungsgrad des Wechselrichters hWR95% 195% 95%

Ergebnisse

Fläche des Modulfeldes 82,4 82,4 0,0 0,0 0,0 0,0 m²

Freie Fläche auf dem ausgewählten Bauteil 44,0 423,5 m²

Belegung des Bauteils 65% 16%

Jahresverluste durch Verschattung 0 0 kWh

Summe

Jahres-Stromertrag nach Wechselrichter Absolut 15704 29909 45613Bezogen auf die überbaute Fläche 19,5 37,2 57Spezifischer PE-Faktor (nicht erneuerbare Primärenergie) 0,30 0,11 kWhprim_ne/kWhEnd

Spezifischer CO2-Äquivalent-Emissionskennwert der Anlage 44,5 20,9 g/kWh

CO2-Äquivalent-Emissions nach 1-CO2 -Faktoren GEMIS 4.6 (Deutschland) 2104,4 3110,5 5214,9

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4. Conclusion

The Passive House is the world‘s leading standard in energy efficient design. It started out as a construction

concept for residential buildings in Central Europe. Today, the Passive House Standard can be implemented in

all types of buildings almost anywhere in the world. The demand for Passive Houses as well as information on

and experience with Passive Houses has been increasing at an enormous pace, reflecting the trend-setting

developments in this field.

This study has shown that by applying these basic recommendations and the components available on the

market today, it is possible to realize Passive House school buildings with various design concepts.

Retrofit of school buildings to the passive house standard can be planned using the PHPP and that, except for

some clearly defined features, the same focal points had to be taken into consideration for these as for

residential or office buildings in the Passive House Standard.

An important boundary condition is the intermittent use with temporarily extremely high internal loads. The

temporal average value of the internal loads with 2.8 W/m² on average is not much more than the values for

residential use. Setback phases play an important role in school buildings. A tool is available for determining the

expected effective temperature reduction [PHPP 2015] .

In school buildings particular attention should be paid to specific use in summer. Sufficient shading, night-time

ventilation and high internal heat capacity are all imperatives. If it is not possible to meet one of these

requirements, equivalent compensation must be provided – this can be concrete core temperature control or

the use of adequate heat exchangers, for example.

For reheating after setback phases, the central heating generator must be able to provide a sufficiently high

output (in the range of 50 W/m² of heated useable area). The pre-heating phase must be regulated via time

control and internal temperature measurement.

Based on all previous experiences, the Passive House concept has proved to be just as successful for schools,

where it is particularly advantageous due to the ventilation system’s importance.

5. How to go about it

Why do we have to spend so much time thinking about energy-saving building in renovations, and how can we

motivate people to conserve energy? There are three reasons why we should switch to energy-efficient

construction and renovation as quickly as possible.

1st reason: Europe plans to reduce its carbon emissions by 30-40 percent by 2020 and by 80 percent by 2050.

2nd reason: Along with renewable energy, energy-efficient construction and renovation must compensate for

constantly rising energy costs.

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3rd reason: Energy-efficient construction and renovation reduces construction defects and makes buildings

healthier and more comfortable, thereby increasing the long-term value of our buildings.

Climate change affects us all. In order to effectively tackle climate change, we must reduce our energy

consumption significantly in the long term. This means efficient use of available energy and placing maximum

priority on saving energy. Cities and local authorities are important actors when it comes to climate protection –

at the local level, with every individual, every community, in every region.

On average, about 40 % of the total energy consumption in industrialized countries is used for buildings. That is

why significant improvement of the energy efficiency of buildings has considerable impact on the overall

assessment of a town, municipality or urban district in terms of energy. Due to the long service life of buildings,

a consistent approach is especially important in this respect.

For more than 20 years, the Passive House Institute has committed itself to the advancement of the Passive

House Standard, with which an improvement of 40 to 75 % in the energy consumption for heating and cooling

of new builds can be achieved; in the case of refurbishments, reductions of 75 to 95 % are commonplace.

Athens 8/5/2015

Stefanos Pallantzas, Civil Engineer, Certified Passive House Designer

Athanasia Roditi, Architect, Certified Passive House Designer

Lymperis Lymperopoulos, Architect

Aggeliki Stathopoulou, Civil Engineer

27th elementary school of Piraeus enerPHit report

Engineering

Transcript of 27th elementary school of Piraeus enerPHit report