Building Integration Report Aug 2002

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Energy, Environment and Sustainable Development

June 2002

Building Integration

Common Work Package

Workpackage 3


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RESURGENCE NNE5-2001 - 00340 18/10/02 Building Integration Report .

Energy, Environment and Sustainable Development 2


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Table of contents

Building integration of PV-modules................................................................... 4

Types of PV-modules. ...................................................................................6

Examples of building integration of PV-modules ...........................................9

Total economic analysis concerning building integrated PV-modules togetherwith general energy saving measures.............................................................19

Total economic analysis concerning use of PV-modules for a housingscheme........................................................................................................19

Total economic analysis concerning use of PV-modules and energy savingsin connection with renovation of a one-family house from 1970. ................. 24

Energy consumption....................................................................................24

Economy .....................................................................................................25

Environmental improvements ......................................................................26

Total economic analysis concerning use of PV-modules for a new school inOvnhallen in Valby, Copenhagen..............................................................27


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Building integration of PV-modules

Already today PV-modules are utilised in many places as so-called standalone systems where an alternative electricity supply would be expensive (e.g.calculating machines, monitoring, pleasure boats, lighthouses, traffic lights andmountain cottages). But within the last few years the interest has increased

concerning demonstration of PV-modules in buildings for local electricityproduction with connection to the electricity supply system and with sale of PVelectricity in the same way as it is usual with windmills.

It is, however, expensive to install grid connected PV-systems. But due to thequick increase in the production, see figure 1.1, and the decreasing price ofPV-modules, where the price has been reduced by 50% every fifth to seventhyear since 1978 there is anyway in many countries a belief that this technologycan play an important role in a future solar energy society.

To obtain the best possible integration and economy for grid connected PV-modules it is necessary to focus on the possibilities to integrate these in south,south-east and south-west facing facades and roofs on buildings and otherconstructions. The possibilities are great. A German investigation has e.g.documented that building integrated PV-systems can cover up to 40% of theexisting electricity consumption in households.

And e.g. the World Watch Institute has the opinion that on a long view PV-modules can be part of a hydrogen based energy system that also includesfuel cells and a possibility to store the energy. There will also be decentralisedsolutions here which can e.g. be used in the transport sector too.

In a number of countries, the development of building integrated PV-modulesthat are connected to the electricity supply system has been quite fast, alsosupported by large national plans for PV-implementation in building.

The initial cost of PV-modules has until now been high and has thus preventedthe extension. But improved efficiency, the increasing environmentalawareness and improved agreements concerning network connected PV-systems and an improved support policy are, however, now expected to turnthe standstill and create a genial soil for an intensive development and use ofPV-modules that within the next years can get a decisive importance to the

pricing.

Integration of PV-modules has in addition to the energy effect a considerableand challenging influence on the architecture. In recent years a number ofgood examples of PV-integrated building parts have been developed andseveral producers of building units, e.g. window producers, have presentedsystems for integration of PV-modules.


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Developme nt in the production kapacity for PV-modules at wo rld level

201

74

401

288

155

201

172

126

89

28

139

54

95

61

54

8

48

80

26

19

23

19

16

14

14

59

0

50

100

150

200

250

300

350

400

1996

1997

1998

1999

2000

2001

M W

Europe ex.

Germany

Australia

USA

Asia

except

Japan

Japan

Poly

crystal-

l ine

Mono

crystal-

l ine

Thin film

Distr ibu-

tion

area

Types of

P V-

modules

Germany

Producers

Other

Photowatt

MitsubishiSanyo

Isofoton

RWE solar

AstroPower

Siemens &

Shell Solar

Kyocera

BP Solar

Sharp

Figure 1.1. Development of the production capacity for PV-modules at worldlevel (Ref. Photon 1998-2002)

Figure 1.2. Examples of PV-modules integrated windows.

A: Example from a utility companys headquarter in Aachen in Germany fromoutside.


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B: PV-modules integrated in a roof window in the energy balance house inAmersfoort in Holland.

C: Window integrated PV-modules constitute the facade on the library inMataro near Barcelona in Spain.

1.1 Types of PV-modules.

PV-modules do in most cases consist of silicon. There are in principle twotypes of silicon based PV-modules: crystalline and amorphous, of which the

last type is a so-called thin film PV-module where a very thin PV layer isapplied to a glass plate.

The crystalline module exists in two types: monocrystalline and polycrystalline.The monocrystalline is the most efficient with up to 15-17% utilisation of theinsulation but it is also the most expensive. Polycrystalline PV-modules areeasier to produce and therefore cheaper. The efficiency is only a little lowerthan for the monocrystalline with approx. 12% efficiency. The visualappearance is different for the two types of crystalline PV-modules, as close byyou can see many nuances in polycrystalline PV-modules.


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The cheapest solution per m is the amorphous thin film PV-modules which inreturn only has an efficiency of 4-6%. The PV-modules are produced with anoutput of approx. 10% but they are not constant enough to keep up thisefficiency in practice.

The amorphous cells have a number of advantages compared to the

crystalline excluding the yield:

The price is 1/3 of the crystalline;

They use less energy by production;

They have a uniform colour and a homogeneous appearance;

They are less sensitive to partial shadow areas;

They are less sensitive to temperature variations;

There are great possibilities to make them cheaper.

The individual PV-modules are opaque but e.g. crystalline PV-modules can beplaced with air between the cells in a glass surface with which the entiremodule gets some kind of a transparent appearance. Modules built withclosely spaced PV-modules are not transparent.

In addition to amorphous PV-modules there are a number of other new typesof thin film PV-modules that are interesting especially as regards the price.This is CIS and CIGS modules, where the efficiency is apparently approx.10%, and CdTe modules (cadmium telluride).

The problem for the last mentioned is, however, that cadmium is included inthe product, just as it e.g. is in rechargeable nickel cadmium batteries. Even

though it is assured that they are 100% reusable, this must be demonstrated inpractice before you with a clear conscience can consider to use these PV-modules that can apparently be produced at a low price. Finally the organicPV-modules can be mentioned, which can in principle be produced at a lowprice but that are still on the basic research phase.

PV-modules are always built of a number of interconnected cells thatconstitute a module. One cell can only produce 0.5 V. In practice a number ofseries connected cells are connected in a module to obtain a useable poweron e.g. 12 V.

PV-modules can be put together to large surfaces. As the produced electricityare DC it is either going to be used at once for operation of electricalequipment that can use DC electricity or it is transformed into AC electricity.

If an inverter is installed, a possibility to connect the system to the ordinaryelectricity supply system is obtained. This means that in periods where theelectricity production is larger than the consumption, the electricity can be soldto the ordinary electricity supply system. Another solution is to utilise a so-called netmetering concept where you will utilise an electricity meter that canmeasure both ways. The result of this concept is that you will then get apayment for the PV electricity which is the same as the

normal electricity price. But if it is possible to get higher


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prices, e.g. in connection to given electricity sale from PV then this is a bettersolution.

1.2 Advantages of building integration of PV-systems

PV technology has great prospects of ensuring a renewable energy based

energy supply in cities. Here good architectural solutions will, however, be amust if large-scale implementation shall be approved by the public.

In connection with new building and rehabilitation projects considerablesavings can be obtained, both as regards materials and installations, byintegration of PV-modules in the ordinary faade or roof surfaces on a building.If a standard building integrated PV-system is used, it can in some cases bepossible to obtain a lower price of the PV-module facade or roof than the priceof only the PV-modules, as the possible savings of faade or roof surfaces canbe considerable.

New investigations show e.g. that on office blocks, where the faade surface isoften very expensive, electricity from PV-modules will within a few years becompetitive to ordinary electricity from the electricity supply system.

In office buildings, the electricity production from the PV-modules does oftenfollow the variations in the electricity demand which means that a peak shavingeffect can be possible. By installation of building integrated PV-modules it isalso easy to utilise the production of both electricity and heat from the PV-modules. This can increase the total utilisation of the solar energy from thebuilding integrated PV-modules. The electricity production from the PV-modules can in some cases also be increased when they are cooled, e.g. byheating of ventilation air in connection with a solar wall with built-in PV-modules. The above mentioned solution has also advantages as regardsobtaining the best possible balance between the energy that is used forproductions of typical PV-modules and the yield that can be obtained within thelifetime of the PV-modules. Here it should in general be aimed to reduce thenecessary energy consumption for production of PV-modules at the same timeas obtaining the highest possible yield.

PV-modules can on a long view also operate together with natural gas firedlocal combined heat and power systems in a beneficial way for the society.

The heat demand during the summer is not very large and it sets a limit for acombined heat and power production in this period. Electricity production fromPV-modules increases the local electricity production, also resulting in reducednet losses. Electricity from PV-modules does neither compete with utilisation ofsolar heating for hot water.

When building integrated PV-modules are looked at, the experiences fromcarried out projects have shown examples of both very expensive solutionsand in some cases solutions that does not cost extra because they are buildingintegrated. This will in the writers opinion be an important item to focus on inconnection with the next years development work about

PV-modules.


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It will here be the aim to develop PV-designs at lower prices than today andtherefore it is a great challenge to get integration designs developed for PV-modules for roofs and facades in buildings that does not results inconsiderable additional expenses.

It is here an obvious possibility to aim at a close cooperation between PV-module suppliers, PV-module specialists and building component producers.At the same time it is necessary to focus on hybrid utilisation of PV-modules tosecure that a market for utilisation of building integrated PV-modules is createdquickly on a normal financial basis.

This can e.g. include use of PV-modules for preheating of ventilation air anduse of PV-modules for direct operation of ventilation. But also use of e.g. PV-modules for direct operation of lighting systems or PV-modules as part ofdaylight solutions or sun protection solutions are interesting to work on.

1.3 Examples of building integration of PV-modules

In the following there are a number of illustrations of how PV-modules can beintegrated in buildings in different ways. Example in figure 1.2 and figure 1.8-1.16 are from Cenergia-coordinated projects.

Figure 1.3. Roof design in Amersfoort in Holland, where the whole roof iscovered by PV-modules.


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A: Amorphous PV-modules from Fortum in Finland installed in the windowparapet.

B: PV-modules integrated around a window.

Figure 1.4. Examples of integration of PV-modules in the Hedebygade blockat Vesterbro in Copenhagen.


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Figure 1.5. PV-modules on the facade on the cleaning firm R98s head officein Copenhagen.


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Figure 1.6. PV-module/slate roof design from Danish Eternite (new 60 60 cmsolution and a smaller solution) on a sports centre in Smrum, Denmark(Based on a cooperation with the Swiss company Atlantis Solar)

Figure 1.7. PV-modules integrated in the facade on the Brundtland centre inToftlund, Denmark.


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Figure 1.8. Sun protection with PV-modules from the Danish company ALU-PV/Dasolas.

Figure 1.9. Installation of PV-modules on a gable in Viktoriagade 10B atVesterbro, Copenhagen. Here ventilation air is preheated behind the PV-modules.


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Figure 1.10. The Danish roofing felt producer Icopal has carried out a veryinteresting development of an installation system for PV-modules for roofingfelt roofs where they can give the usual 15 years guarantee.

PV-module

Perforated place

Insulation

Figure 1.11. Folehaven in Valby Copenhagen. Rockwool Prorock insulation

system with PV-modules.


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SOLGREENNew mountin structure for v-modules on reen flat roofs

TECHNOLOGY: Structure is fixed by the substrate of

the roof vegetation

flexibility for level over ground

different inclination angles between

20 and 30

applicable for modules and laminates

Module fixation by glueing or bymetal clamps

PURPOSE:The goal was to develop a light-

weight system, which uses the existing

substrate on the flat roof to withstand the wind

forces and avoids conflicts with roof vegetation

and maintenance.

APPROACH:The Solgreen project teamrealised different methods of resolution in morethan 4 pilot- and demonstration-systems inorder to develop a new , material saving,aesthetically pleasing and cost-efficiencymounting structure.

P. Toggweiler1, J. Rasmussen

1, and J. Bonvin

2

1 Enecolo AG Lindhofstrasse 52 CH-8617 Mnchaltorf

Phone +41 1 994 90 01 Fax +41 1 994 90 05 [email protected]

2Solstis Srl Sbeillon 9b CH - 1004 Lausanne Tel.: 021 622 50 75 Fax: 021 622 50 71

0

36.0

72.0

108.0

144.0

180.0

216.0

252.0

288.0

324.0

360.0

00:22 01:22 02:22 03:22 04:22 05:22MM:SS 17:04:10

93.270

154.163

55.464

5.366

353.717

0

0

0

0

0

0

0

Kraftm_1

Kraftm_2

Kraftm_3

Windgesch

Windricht

Picture: Forces as afunction of wind

speed

STUDIES:

Monitoring and evaluation of

spontaneous and planted vegetation

Investigation of wind force by data

Figure 1.19. Example of PV-modules integration system for green flats rooffrom Switzerland.

Solgreen - Photovoltaik und Grndach


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Unter dem Namen Solgreen wird die Kombination von Photovoltaik undGrndach angepriesen. Die gemeinsame Dachnutzung muss nicht unbedingtzu einem Konflikt fhren. Im Gegenteil, neue Lsungen sind entwickeltworden, die ein vorteilhaftes Miteinander ermglichen. Die Enecolo AGarbeitet seit 1997 gemeinsam mit EPFL-LESO und Solstis amForschungsprojekt Solgreen, seit dem Jahr 2000 ist auch die Firma Ernst

Schweizer Metallbau beteiligt.Enecolo und LESO haben1997 ein Patent angemeldet. Das BFE und das ewzhaben mit Beitrgen die Entwicklungsarbeiten gefrdert.

Zielsetzungen: Die neu entwickelten und erprobten Aufstnderungsvariantensind fr flache und leicht geneigte Dcher geeignet. Die Lsungen basierenauf folgenden Grundstzen:- Dachsubstrat als Ballast fr die Unterkonstruktion (keine zustzlicheDachlast)- Minimierung von Umweltbelastungen und Kosten durch sparsamenMaterialeinsatz

- Erhalt und Frderung von Fauna und Flora- Sicherstellung der Wasserspeicherfhigkeit- sthetische Integration der Anlage- ausreichende Bodenfreiheit zum Schutz der Module gegen Beschattungdurch Pflanzen- gnstige, rasche und einfach Montage

Realisierte Anlagen: Im Rahmen vom Projekt Solgreen wurden nebenzahlreichen Prototypanlagen, die 26 kWp P&D Anlage KraftWerk1 in Zrichund eine 18 kWp Anlage auf dem Schulhaus Wasgenring in Basel realisiert.

Weiterentwicklung:Die ersten Anlagen zeigen deutlich: Solgreen bewhrt sich und es ist eine guteLsung.Durch gezielte Verbesserungen und Weiterentwicklungen soll das Systemnoch besser und konkurrenzfhiger werden.


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Figure 1.20. Example of PV-module system from the Netherlands, which hasbeen developed for a simple and and easy flat roof integration.


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Total economic analysis concerning building integrated PV-modulestogether with general energy saving measures.

In the following is shown three examples from Denmark of how buildingintegrated PV-modules can be used already now in a cost effective waytogether with energy saving packages based on a 50% funding for the PV-

modules.

Total economic analysis concerning use of PV-modules for a housingscheme.

In the following there is an example concerning a housing development with 42flats. Four alternatives to a normal reference solution as shown in the followingis here considered.

The investment in a traditional heat supply to the houses (solution 1) is shownin the following together with four alternative solutions. There is a solution with

heat recovery ventilation (solution II) and one where this is combined withutilisation of PV-modules (solution II a). There is a solution with heat recoveryventilation and air heating (solution III) and one where these are combined withutilisation of solar heating and PV-modules and additional insulation (III a).

Solution I (reference):- Insulation standard according to the Danish building regulations;- Heating by radiators;- Ordinary exhaust ventilation, 60W per dwelling in electricity consumption.

Solution II (reference including ventilation with heat recovery:

- As I but with 80-90% efficient heat recovery, 30 W per dwelling in electricityconsumption for ventilation tower.

Solution II a (reference including ventilation with heat recovery ventilation andapprox. 2 m PV-modules per house as basis of CO2 neutral ventilation):- As solution II but with PV-modules with a production equal to the annual

electricity consumption (91 m PV-modules), including 50% funding.

Solution III (As II but with additional insulation and air heating, effect demand 3kW per house):- Efficient heat recovery ventilation;- Additional insulation;

- Air heating with maximum 40-50 W electricity consumption per house forventilation;

- Heating via domestic hot water heating;- Solar heating for domestic hot water.

Solution III a (as III but with approx. 3.5 m PV-modules per dwelling):- As solution III but with PV-modules (153 m) and 50% funding.


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Table 1.1. Investments for three alternative solutions for heat supply.I II II,a III III,a

1. Heating plant 100.000 100.000 100.000 75.000 75.000

2. Distribution, RV 210.000 210.000 210.000 0 0

3. Heating 1.260.000 1.260.000 1.260.000 100.000 100.000

4. Ventilation 504.000 1.134.000 1.134.000 1.680.000 1.680.000

5. Additional insulation 0 0 0 210.000 210.000

6. Solar heating 0 0 0 0 173.793

7. PV-modules 0 0 321.930 0 536.550

Total 2.074.000 2.704.000 3.025.930 2.065.000 2.775.343

Total including VAT 2.592.500 3.380.000 3.782.413 2.581.250 3.469.179

The table does only include the parts that are important to the comparison ofthe five solutions. A traditional solution with central heating and radiators andwith ordinary exhaust ventilation is thus DKK 2,592,500. If efficient heatrecovery ventilation is introduced, the investment will increase with DKK787.500. If PV-modules are installed too, the investment will increase with DKK

402,000. If additional insulation and air heating are utilised together with heatrecovery, the total expenses will be DKK 2,581,250, which is almost the sameas the reference. If also solar heating is used as a supplemental heat sourceand PV-modules for electricity production is combined with an improvedinsulation and air heating, the investment increases with DKK 888,000compared to a traditional solution. The last solution has more investmentdemanding measures but by using air heating and by using the domestic watercirculation as a heat distribution network for room heating, a traditional radiatorsystem and supply ducts with mixing loops are saved. In this way a goodsolution for the environment with a good indoor air climate is obtained.

0

20

40

60

80

100

120

I II II,a III III,a

kWh/m

Heat consumption Electricity consumption

Figure 1.21. Annual heat and electricity consumption for the reference project(I) and 4 alternative solutions (ventilation with heat recovery (II), this with PV-modules (II a), ventilation with air heating (III) and this with PV-modules andsolar heating III a)). Reduced CO2-emission is 17, 20, 17 and 25%respectively.


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By introducing the measures mentioned for solution III, the heat and electricityconsumption will be reduced, as shown in figure 1.21. The heat consumptiondecreases with 35% and the electricity consumption with 15%. The total resultis an environmental improvement with a reduced CO2-emission of 25%.

An investment in environmental improvements will be favourable for the

tenants if the total costs are not higher than if the dwelling is built withtraditional solutions. The total costs can in this case be calculated as theexpenses to cover the investment costs, expenses for additional maintenanceand expenses for electricity and heating. Figure 1.22 shows the first yearsexpenses for electricity, heating, maintenance and the investment in energyenvironmental measures. The investment is based on an annuity loan over 30years. The figure shows that part payment of the investment and expenses formaintenance increases concurrently with introduction of different measures butthe supply expenses decrease at the same time.

It can be expected that the costs for the tenants increase due to the increasingdistrict heating and electricity prices. A present value calculation includesfuture rise in energy prices. The result of a present value calculation is shownin table 1.1. It shows that the total present value is smaller than the referencefor all four alternative solutions but it is smallest for the solution with air heatingequal to the fact that the total costs during a long period are smallest for thissolution. In other words, the investment in ecological measures is a favourablesolution for the tenants. A considerable environmental improvement ismoreover obtained.

0

2.000

4.000

6.000

8.000

10.000

12.000

14.000

16.000

18.000

I II II,a III III,a

rligudgiftpr.bolig

Investment Maintenance Heating Electricity

Figure 1.22. First years expenses in an average dwelling. The investment isrepaid over 30 years and with 5% p.a. Maintenance is 2% of the investment. Areference (I) is compared to four alternative solutions (ventilation with heatrecovery (II), this with PV-modules (II a), ventilation with air heating (III) andthis with PV-modules and solar heating III a)).

It is furthermore suggested that it as a general requirementmust be documented that the dwellings are airtight and


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without cold bridges in the construction. This can be done by follow-up duringthe building process, including specialist assistance and by introducing a so-called blower door test.


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Table 1.2. Present value calculation of five alternative solution proposals to the heat supply.

Technical

data

I II II,a III

Investments, I0 2.592.500 3.380.000 3.782.413 2.581.2

Annual maintenance, Ud 51.850 67.600 75.648 51.6

Annual expenses of electricity and heating, Uf 467.544 389.190 374.474 387.4

Expected financial life-span, n 30 30 30

Financial conditions

Nominal rate, Rn 5% 5% 5%

Rate of taxation of interests, S 0% 0% 0%

Expected price rate of maintenance, Iud 2% 2% 2%

expected price rise rate of supply, Iuf 3% 3% 3%

Calculation of actual interest rates

Actual interest rate of maintenance, Rrud 0,0304 0,0304 0,0304 0,03

Actual interest rate of supply, Rruf 0,0209 0,0209 0,0209 0,02

Calculation of present value factors

Present value factor, maintenance, Fnuud 19,50 19,50 19,50 19

Present value factor, supply, Fnuuf 22,13 22,13 22,13 22

Calculation of present value

Present value of continuing maintenance, Ud 1.011.151 1.318.298 1.475.251 1.006.7

Present value of continuing supply costs, Uf 10.346.604 8.612.665 8.286.987 8.574.1

Investments, Io 2.592.500 3.380.000 3.782.413 2.581.2

Result, present value = Io+Ud+Uf 13.950.254 13.310.963 13.544.650 12.162.1


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Total economic analysis concerning use of PV-modules and energysavings in connection with renovation of a one-family house from 1970.

The house is a 150 m one-family house that is approx. 30 years old, wherewe want to give the house an overall renovation where both walls, windows,floor and roof are changed. In the roof a new overhead light will be set up thatwill improve the daylight quality in the house. In addition to this we areinterested in getting ventilation with heat recovery to obtain a good indoor airclimate, just as we are interested in solar heating for domestic hot water. Thequestion is just how economical these things are for the house owner.

Energy consumption

The energy consumption in the house for heating, domestic hot water, lightingand electric appliances can be put at:

kWh kWh/mHeating 17,556 121Domestic hot water 3,000 20,7Electricity 4,640 32

The heat consumption for heating is calculated according to the Europeanstandard based on the actual measurements and an average indoor airtemperature of 20C. Energy for the domestic hot water, lighting and electric

appliances are assumed on the basis of what is usual in a typical one-familyhouse. Heat consumption in addition to this is net consumption, which meanswithout loss in the oilfired furnace. If the efficiency of the oilfired furnace isassumed to be 85%, the total annual energy consumption for heating anddomestic hot water will be 24,184 kWh equal to 2,418 litre oil per year.

The insulation standard of the house is equal to the requirements on the timeof erection, which means below the present standard. It is therefore possible toimprove the house from an energy-wise point of view. In figure 1.23 the annualcalculated oil consumption for heating and domestic hot water are shown withfive different improvement suggestions.


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Energy consumption

0

5000

10000

15000

20000

25000

30000

Basic Insulation Windows Ventilation Solar heating PV-modules

kWh/year

Heating Electricity

Figure 1.23. Energy consumption for heating and domestic hot water andelectricity consumption shown for different energy measures when these areadded to the reference.

If the external walls are insulated on the outside with 100 mm insulationmaterial and the ceiling and floor with 100 mm too, the heat consumption willbe reduced with 25%. If all windows and doors are replaced by low-energyglass the heat consumption is reduced by further 22%. If ventilation with

efficient heat recovery is introduced at the same time and the house istightened carefully the consumption is reduced by approx. 11%. If solarheating is installed (contribution ratio) as a supplemental heat source to thedomestic hot water, the heat consumption will be reduced by 10%. The lastcolumn shows the importance of mounting a 6 m overhead light and a 10 mPV-system. A modest increased of the heat consumption and a reduction ofthe electricity consumption will take place, partly from the electricity productionin the PV-modules and partly from an increased insulation through theoverhead light.

By implementing all the measures a saving of the heat consumption of 64%

can be obtained, equal to a annual oil consumption of 860 litre. Theconsumption can be reduced further by frequent use of a woodburning stove.The electricity consumption is expected to be reduced by 25% even though thefans in the ventilation system and the circulation pump in the solar collectorsystem are the occasion of a small increased electricity consumption.

Economy

The different energy saving measures demands an investment. If it isanticipated that the investment is financed by an annuity loan (5%, 30 years)the first years expenses for repayment and expenses for energy will be as


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shown in figure 1.24. The assumed prices are: electricity 1.66 DKK/kWh, fueloil 0.56 DKK/kWh and a 50% tax saving on interest is included.

If an increase of the energy prices is considered the profitability can becalculated by means of the present value method. This is shown in table 1.3.When the present value of the investment is positive the investment isprofitable. The utilisation of PV-modules gives together with the othermeasures a positive economy in a 30 years period when 50% funding for thePV-modules are obtained.

By assessment of the profitability the increase of the value of a house is alsogoing to be considered and it can change the result considerably.

0

5000

10000

15000

20000

25000

30000

Basic Insulation Windows Ventilation Solar heating Solceller

DKKperyear

Repayment of loan Expenses for energy

Figure 1.24. The first years expenses for heating and electricity andrepayment of loan for energy saving measures. For all alternative there is anextra cost in the first years. Over 30 years there is a balance in the economy.

The first years expenses for the energy saving measures are increased a little(approx. 10%) but in a number of years it is an advantage to introduce the

shown measures on the basis of a total economy assessment and the CO2emission from the house is reduced by 50%.

Environmental improvements

If the energy consumption is calculated to CO2 emission a reduction from9,500 to 4,500 tons per year is obtained, equal to 52% per year. The result isshown in figure 1.25.


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Annual CO2 emission

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000


kgCO2

Heating Electricity

Figure 1.25. Environmental improvement shown as reduced CO2 emission.


Investment, Io (DKK) 0 170.000 207.500 242.500 272.500 322.500

Current expenses per year, uo (DKK) 0 0 0 200 450 450

Annual saving, bo (DKK) 0 3.394 6.414 7.409 8.677 10.718

Expected economic life, n 30 30 30 30 30 30

Nominal rate, Rn 5% 5% 5% 5% 5% 5%

rate of taxation of interest, S 50% 50% 50% 50% 50% 50%

Expected price increase for current expenses., Iu 2% 2% 2% 2% 2% 2%

Expected price increase for energy, Ie 3% 3% 3% 3% 3% 3%

Real interest rate, expenses, Rru 0,0049 0,0049 0,0049 0,0049 0,0049 0,0049

Real interest rate, savings, Rrb -0,0049 -0,0049 -0,0049 -0,0049 -0,0049 -0,0049

Present value factor, savings, Fnvb 27,84 27,84 27,84 27,84 27,84 27,84

Present value factor, supply, Fnvu 32,38 32,38 32,38 32,38 32,38 32,38

Present value of current expenses, Uo 0 0 0 5.567 12.526 12.526

Present value of savings, Bo 0 109.902 207.674 239.887 280.967 347.052

Investeringsbelb, Io 0 170.000 207.500 242.500 272.500 322.500

Present value of the proejct, U=Bo-Uo-Io 0 -60.098 174 -8.180 -4.059 12.026

Table 1.3. Calculation of present value costs over 30 years for a reference andfive alternatives added to the reference. This means ref. (basic) ref. +

insulation (insulation) and so on. It is seen that the combined PV/daylightsolutions leads to a positive economy over 30 years.

Total economic analysis concerning use of PV-modules for a new schoolin Ovnhallen in Valby, Copenhagen

As part of the work with a PV implementation plan for the city area of Valby inCopenhagen, a suggestion for large-scale utilisation of PV-modules has beendeveloped for a new school that is going to the made in Ovnhallen in Valby.This is one of the former industrial buildings that will be converted in

connection to the so-called Example Project in Valby.


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The calculations from Cenergia show that by use of 1,400 m PV-modules it ispossible to obtain a complete CO2-neutral solution for the school so the annualenergy consumption for heating and electricity is equal to the energy yield from

the PV-modules.

Figure 1.26 shows a visualisation of up to 1,500 m PV-modules for the newschool in Ovnhallen in Valby, which was used before to produce porcelean.

Table 1.4 shows the investments for three different energy saving measurestogether with a total energy saving solution and a Zero-energy solution where1,400 m PV-modules are used. Figure 1.27 shows savings of the electricityand heat savings by these measures. Figure 1.28 shows the saved quantity ofCO2 as to these measures and how one by PV-modules can get a totally CO2-neutral building.

Table 1.5 shows the total economy for all the measures including PV-moduleswhich on the basis of the given conditions will be positive for the builder over a30 years period, including 50% funding to the PV-modules.

Figure 1.26. Calculations show that it is possible including 50% funding forPV-modules to have a positive economy over 30 years if you will build a zero-energy school in Denmark that is totally CO2-neutral by use of 1,400 m PV-modules in the roof together with energy savings.


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Investments:Electricity

savings

Heat savings Total electricity

and heat

savings

Total

including VAT

Total

including

VAT/mReference 0 0 0 0 0

Heat recovery 500.000 1.500.000 2.000.000 2.500.000 432

Additional insulation 500.000 700.000 1.200.000 1.500.000 259

Low-energy windows 500.000 500.000 1.000.000 1.250.000 216

Total energy saving concept 500.000 2.700.000 3.200.000 4.000.000 691

Zero-energy design with PV-modules 500.000 6.200.000 6.700.000 8.375.000 1.447

Table 1.14.

Heat and electricity consumption

-20

0

20

40

60

80

100

120

140

Reference Heat recovery Addi tionalinsulation

Low-energywindows

Total energysaving concept

Zero-energydesign with PV-

modules

kWh/m

electricity

heating

Figure 1.27. Reference situation for the school in Ovnhallen as regards heatand electricity consumption compared with 3 different energy saving measuresindividually and altogether. Furthermore it is shown how utilisation of 1,400 mPV-modules can result in a CO2 neutral building design that can eventually beconverted to an electricity zero-energy solution by means of a heat pump.


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CO2 emission

-50

0

50

100

150

200

Reference Heat

recovery

Additional

insulation

Low-energy

windows

Total energy

saving

concept

Zero-energy

tonCO2

heating

electricity

Figure 1.28. Comparison of CO2 emission for the school in Ovnhallen for thereference situation and three different energy saving measures respectively,both individually and altogether. Furthermore it is shown how a CO2 neutralbuilding can be obtained by 1,400 m PV-modules on the roof of Ovnhallen.

First year's expenses,

Investment: annuity loan (5%, 30 years)

0

20

40

60

80

100

120

140

160

Reference Heat recovery Additional

insulation

Low-energy

windows

Total concept Zero-energy

DKK/m

Investment Maintenance Supply

Figure 1.29. Comparison of first years expenses for the three different energysaving measures, the total energy savings and for the zero energy designbased on 1,400 m PV-modules. The energy saving concept has almost thesame costs as the reference while the zero energy design costs more the firstyear.


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Technical data per living space Reference Heat

recovery

Additional

insulation

Low-energy

windows

Overall

concept

Zero-energy

Investment, DKK/m Io 0 432 259 216 691 1.447

Maintenance costs, DKK/year/m uo 0 9 5 4 14 29

Saving, DKK/year/m bo 0 47 19 23 56 95Expected service life n 30 30 30 30 30 30

Financial conditions

Nominal estimated rate of interest rn 5% 5% 5% 5% 5% 5%

Rate of taxation s 0% 0% 0% 0% 0% 0%

Expected price rise for maintenance iu 2% 2% 2% 2% 2% 2%

Expected price rise for energy ie 3% 3% 3% 3% 3% 3%

Calculation of real rate of interest

Maintenance Rrud 0,0294 0,0294 0,0294 0,0294 0,0294 0,0294

Saving Rruf 0,0194 0,0194 0,0194 0,0194 0,0194 0,0194


Operation Fnuud 19,75 19,75 19,75 19,75 19,75 19,75

Saving Fnuuf 22,58 22,58 22,58 22,58 22,58 22,58


Present value of maintenance Uo 0 171 102 85 273 572Present value of the saving Bo 0 1.054 440 528 1.268 2.142

Investment Io 0 432 259 216 691 1.447

Result: Present value = Bo-Uo-Io 0 451 78 227 303 123

Table 1.5. Present value calculation over 30 years for three different energysaving measures and an overall energy saving solution and a zero energydesign using PV-modules including 50% funding for these. It is seen that allalternative solutions have a better economy than the reference.

In connection with the school project in Valby it is also suggested to look onthe possibility to utilise an electric heat pump for heat supply because an

electricity zero-energy solution can be obtained this way, which at the sametime can have an advantageous effect as regards a reduction of problems withelectricity overflow in the electricity system in the winter.

Documents

Building Integration Report Aug 2002