STUDY OF A HYBRID PV INTEGRATED BUILDING APPLICATION IN A WELL CONTROLLED TEST ENVIRONMENT J.J. BLOEM EC -JRC, Institute for Environment and Sustainability, Renewable Energies Unit, I - 21020 Ispra, Italy. E-mail
[email protected] ABSTRACT From the experience gained in several EU research projects, an improved design for a common Test Reference Environment was made allowing the assessment of experimental data for electrical and thermal performance evaluation of photovoltaic systems integrated as cladding components into the building envelope, giving input to modelling work. The specific design of the PV module and test reference environment makes it possible to study through electrical and thermal energy flow analysis, the effect of using different materials for PV modules and construction design of claddings. Beside a general introduction about building integrated photovoltaic applications an outdoor experiment and modelling results of a glass-glass PV module with forced ventilation is presented. 1. INTRODUCTION The aim of the work is to investigate the heat exchange of a PV device in a typical built environment. From the experience gained in the PV Hybrid Pas [Ref 1,2] and IMPACT [Ref 3] research projects, an improved design for a common test reference environment was made allowing the assessment of experimental data for electrical and thermal performance evaluation of hybrid PV systems. Particular attention has been given to the specific built environmental conditions for photovoltaic (PV) that is at lower level of irradiation and higher PV module operating temperature. The Test Reference Environment (TRE) is constructed in such a way that the thermal energy obtained by convection and radiation exchanges at the rear of the PV module can be measured accurately [Ref 4]. The test environment box is designed to be placed in the south wall opening of the PASLINK test cell and is composed of an insulated cavity of 10 cm with an air in- and outlet placed at the back of the box. Considering the long wave energy exchange it was decided to have the cavity painted in defined colours. The box is equipped with a number of air and surface temperature sensors, providing detailed data for modelling work. 1.1 Introduction on BIPV Before going into details of this study of a hybrid PV integrated building application a general introduction on Building Integrated PV (BIPV) will be given in order to understand certain developments in this area. Over the past 10 years (1995 – 2005) the interest in renewable energies in general has been increased. When the built environment is concerned in relation to renewable energies, the focus is mainly on solar energy and in this paper in particular on photovoltaic technology. The PASLINK EEIG network [http://www.paslink.org] has a long lasting experience in outdoor testing, analysis and modelling of building components under real test conditions. The interest in studying the overall performances of photovoltaic devices that are integrated in the building envelop came forward from the testing and analysis of passive solar building components. The network started the PV Hybrid Pas project, aiming to study electrical and thermal performance evaluation criteria. The success of this project started several other European projects, such as Prescript [Ref 5], Impact, PV Cool Build [Ref 6], HyPRI. At present true BIPV is not common yet, as can be concluded from a recent study [Ref 7]. About 1% of the installed PV capacity can be regarded as truly integrated in the building envelop. However, other reports [Ref 8, 9] show that the photovoltaic industry is preparing for a considerable increase in production. Some expect 3 Giga Watt of installed PV systems by the year 2010. The outcome of the PV CITY GUIDE project by DG RESEARCH indicates that more than 50% of PV installations will be in urban areas, mainly on roofs of buildings, but large facades are expected to become interesting objects as well once the PV and construction industry develop innovative BIPV products. The recent Solar Generation report [Ref 10] gives expectations of the PV market development until 2020. For the grid connected market in the residential
1
built environment about 27 GWp cumulative is expected to be installed in Europe by 2020, with average size of 3kWp installations. For a good understanding it is important to distinguish between PV-integration into the building envelop and the integration into the electrical network of the building only. The latter case is supposed to have no impact on the thermal balance of the building and is often regarded as an added installation to the buildings energy system. At present by far the most PV applications are rooftop systems. Building envelop integration of PV systems can be categorised in three BIPV groups: roof integrated, facades (windows and curtain walling) and awning devices. Several European Directives [Ref 11 and 12] will stimulate the use of renwable energy technologies in the built environment. Authorities of some European Member States are seeking the best regulations and incentive schemes to attract private people to invest in renewable energies. In residential urban areas this is most visible by roof integrated PV installations, ranging from small 400Wp PV installations to full roof covered installations that can be sized like 3kWp. In figure 1 is illustrated the complexity of a proper integration of PV technology in the built environment.
Figure 1. Complexity illustrated for Building Integrated PV applications. When it concerns integration of photovoltaic technologies in the built environment three industries are involved: the construction, the glass and the photovoltaic industries. The situation at present is that the capacity of PV cell and PV modules production easily can fulfil the demand. Therefore PV industries do not have to look for specific applications in the market. There is more than enough roof area available in Europe to install PV in the coming ten years without additional effort of integrating it in the building envelope. The project PV-Hybrid-Pas [Ref 1 and 2] studied the overall performance of hybrid PV systems, whereas the project Prescript [Ref 5] was investigating the need for prestandardisation. The latter one concluded that grey areas exist for building codes and PV standards and laboratory measurements can not fulfil the need for BIPV system testing. The main objective of the project IMPACT [Ref 3] was to study the heat exchange of a PV module to its direct surroundings and investigate possible improvements for BIPV components and systems. As a conclusion of this brief introduction when may say that initial interest in BIPV was focussed on hybrid application of the incoming solar energy, e.g. electrical and thermal energy, the latter for the purpose of preheating ventilated air. It is expected that in the near future the integration of PV will attract more attention for economical reasons [Ref 23], e.g. to bring overall costs down by integration of electricity generation elements in the existing construction and energy infrastructure of a building and not necessarily the use of warm air in the building. Overheating in Mediterranean climates and the increased electricity consumption for air conditioning could be another BIPV application. Some examples are given in [Ref 24 and 25]. In [Ref 7] the future of PV in the built environment and in [Ref 13] the barriers for BIPV to overcome for a
2
proper market introduction, are discussed. 2. PERFORMANCE EVALUATION OF HYBRID PV COMPONENTS Hybrid PV components, integrated in a building’s skin, are interacting with the building in many respects. This is schematically shown in figure 2. A comprehensive assessment procedure should include the following aspects: 2.1 Electrical performances of BIPV elements The measurement of the electrical performances of PV elements has already been standardised to a large extent. The electrical efficiency however is dependent on the temperature of the PV element. If the heat produced is partly recovered for other purposes in a hybrid component, then this will affect the electrical efficiency. Therefore a combined thermal and electrical performance test in real outdoor conditions is necessary. The project PV Hybrid Pas was using outdoor test cells for a caloric assessment of a hybrid PV system with a closed space, while the project Impact was using the TRE to assess the thermal exchange of the PV module with its environment
Figure 2. Interaction of various phenomena for a hybrid PV component applied to a building. 2.2 Thermal processes at component level Aspects to be investigated are : • Dynamic aspects of U-value in situation without air flow in the cavity • Overall energy performances for the test duration but also for standardised conditions. This requires the combination of realistic measurements with simulations, through so-called scaling and replication techniques. • Dependency of component dimensions. The thermal buoyancy effects (and therefore also the electrical efficiencies) vary as function of the length (height) of the PV component.
3
2.3 Thermal performances in winter and summer time The heat gained through hybrid PV components can be used for heating purposes of the spaces adjacent to these PV facades or roofs. The interaction with the space can be studied by outdoor testing of the component in test cells, where the thermal comfort in the test room can be studied. Based on the results of the test cell’s experiments, the effect of such components on real buildings and in various climates can be studied by simulation (scaling and replication) of the energy, ventilation and daylight performances. The thermal comfort in the room can be evaluated as well. The pre-heating of the air in a hybrid PV component is not always an advantage. In summer time, pre-heated air will have a negative influence on the indoor climate. In practice, different strategies for summer and for winter time are therefore required. Amorphous Silicon type PV cells are transparent for long-wave radiation and also in the case of semi-transparent hybrid PV elements, very high heat flows can pass through the inner surface of the component (partly direct solar gains, partly by radiation due to the high surface temperature of the inner glazing). This is a very important element, which must be included in the evaluation. 2.4 Ventilation performances The utilization of warm air for the purpose of pre-heating in particular for the colder season, needs to assess the ventilation performance of the integrated PV-installation. With respect to the procedures for evaluating the ventilation performances, a distinction must be made between two types of systems: ♦ naturally ventilated systems; The air flow rate varies over time as function of the outside climate, the inner climate and the use of the building. Prediction of the performances is complex. ♦ mechanically driven systems; In this case, the air flow rate should be more or less constant and known, the estimation of the thermal balance is therefore easier to be made. 2.5 Visual performances In the case of partly transparent components, the visual performance of the components and their impact on the visual comfort inside the space are important. Different aspects are involved, such as, daylight availability and distribution inside the spaces, glare problems. 2.6 Maintenance related aspects and durability Maintenance can be a critical aspect, especially given the fact that air is flowing through the component. The aspect of water tightness has to be considered as well. Also, condensation problems can occur when using certain strategies. It is necessary to evaluate whether the commonly used procedures can be used for such components and, if not, to propose alternative procedures. 2.7 Other Performance objectives To understand the building integration issues it is useful to apply a methodology developed during IEA Annex 32 related to the performance of the building envelope, including PV integrated systems [Ref 14]. The design of the building envelope may need to fulfil a number of interrelated performance requirements, including the usual criteria of conventional building components and systems, in order to meet the specification of the client, designer and legislation. Typically, the building will be required to meet the following performance objectives: • Adaptability • Safety • Good comfort • Health • Energy efficiency • Durability • Minimum environmental impact • Optimum total cost • Image A list of requirements (the design matrix as illustrated in figure 3) may be drawn up for the specific component or system, based on the above Fitness for Purpose objectives chosen by IEA Annex 32 for the performance assessment of advanced building envelopes. When adjusted for photovoltaic products intended for integration in the built environment this can be used as a simple design tool:
4
1. 2. 3.
To evaluate the possible impact of the advanced component on the overall building performance compared to a traditional building envelope design. To identify which knowledge domains are necessary to identify the relevant performance indicators. To identify areas where existing tools, standards, codes, etc. are unsatisfactory or should be reviewed.
Figure 3. Design Matrix – Initial assessment of advanced envelope component. As an initial exercise, the impact of the system on each of the requirements list is assessed on a scale from 1 having about the same impact as conventional envelope to 3 having a more significant impact (negative or positive) or a special requirement. The impact of PV on the indoor climate – day lighting, ventilation, thermal comfort, etc. should be considered [Ref 15, 16, 17]. The integration of PV should not compromise energy efficiency in the building – i.e. no additional heating, cooling, ventilation or artificial lighting should be needed. Installation, safety and maintenance issues may differ for building integrated PV (BIPV) compared with traditional building envelopes. 3. TESTING 3.1 Laboratory, outdoor testing of PV modules and BIPV system testing Building designers are interested in performance under operating conditions for a typical climate, season and specific location taking into account the energy use of their design. Integration of PV in the building envelope implies that they have to take into account electrical energy production, but also thermal (avoid overheating in summer) and comfort (daylight, ventilation and quality of air) aspects. A further consideration is that building designers need performance indicators based on climatic variables: ambient temperature, solar radiation, wind and site dependent data such as obstructions giving possible shading problems. The technical data provided by the PV industry is based on standardised measurements under laboratory conditions described in IEC 61215 [Ref 18]. The most important test procedures are: ♦ 10.2 (Standard Test Conditions), ♦ 10.5 (Measurement of Nominal Operating Cell Temperature), ♦ 10.6 (Performance at NOCT) and ♦ 10.7 (Performance at low irradiance). The outdoor tests described in IEC 61215 are concerned with open rack mounted PV modules for optimised inclination. A number of different circumstances occur when PV modules are applied as integrated components in a building, which is far from the Standard Reference Environment as described in the IEC 61215: ♦ The inclination for façade application is typically 90 degrees and for roof applications depending on the roof construction but is seldom optimized. ♦ Free convection at the backside of the PV modules will not occur.
5
As a consequence the most notable differences are in level of irradiation and operating cell temperature. Therefore conversion from PV module specifications at Standard Test Conditions (25 °C, 1000 W/m2, AirMass 1.5 Global) to BIPV applicable electric system design values is of highest priority when the integration of PV in buildings continues to emerge. The main differences are to be found in the convective and irradiative heat exchanges on the rear side of the PV module. These different thermal exchanges cause the NOCT line to move upwards. Thus even if the NOCT - SRE is available the outdoor surroundings may cause a different equilibrium mean solar cell junction temperature due to different irradiative (asphalt, grass, grit) and convective heat exchanges.
2
Irradiance [W/m ] Figure 4. Temperature difference versus Irradiance. In the graph above, the standardized reference points are given, being the STC and NOCT conditions. Looking more in detail to this graph, one may conclude that building integrated PV applications are situated above the NOCT line. Designers and architects therefore need to calculate with extrapolated data from PV industry supplied specifications. The Prescript project aimed to study the necessarily procedures to facilitate the PV industry the required construction norms. It therefore carried out a number of realistic tests under controlled climatic conditions.
Figure 5. The Prescript project: indoor testing of a complete PV roof system in the climatic chamber and simulator facility LS-1 at the EC DG-JRC, Ispra.
6
More and more new PV products are entering the market bigger in size and more complex in operation. BIPV systems should be tested on overall energy (electrical and thermal) performance related to electrical standards and building codes. 3.2 Test Reference Environment The Test Reference Environment (TRE) is a thermally well insulated wooden box that provides a 10 cm wide air gap between the PV module and its rear facing surface (that would be usually a wall). Experience from the previous PV Hybrid Pas project led to an improved experimental set-up with higher accuracy on temperature measurements. Irradiative disturbances from the boundaries of the PV module are strongly reduced. Furthermore the air in- and outlet are placed at the rear and shaded by the box itself. PV modules up to 30 mm thick can be placed simply in the frame of the box.
Figure 6. Initial set-up designed for the Southwall opening of the Paslink test cell.
Figure 7. Improved design as a stand-alone box for more variety of boundary conditions.
Temperature sensors (thermo-couples are used) are positioned as is given in figures 7 and 9 and photo 10. The external sizes are 203 * 203 * 46.5 cm. The used plywood is 15mm thick and the EPS insulation is 100mm thick. The internal opening is a square of 120.6 cm allowing window and/or PV module components with the maximum size of 120 * 120 * 30mm to be measured. The outlet air tube is 200mm diameter.
7
Photo 8. The BIPV-Test Reference Environment at the JRC, Ispra. Air outlet
Figure 9. Horizontal cross-view at level of air-outlet tube and the position of the four temperature sensors. A tube of the same size but with a slit of 25 mm over the length of the gap between the PV module and the rear facing wall has been used to spread the flow as homogeneous as possible along the rear of the module. See photo 10 and 11. Special attention has been given to the temperature difference measurement between air in- and outlet. A thermo-couple pile consisting of 8 thermo-couples is put in place. The sensors are glued on a copper plate of 1cm2 and give some thermal mass to the sensor.
Photo 10. The air-gap inlet with four piled temperature sensors. By placing different materials at the rear facing surface, the boundary conditions for different experimental conditions, the set-up of the PV module can be changed easily. An aluminium sheet with several fins of 5 cm length was used in one of the experiments, in order to change the radiative and convective heat exchange.
8
Photo 11. The air inlet opening and the air outlet tube. The air flow rate is measured at the bottom end of the tube. The air flow is measured in the outlet tube by means of a hot-wire anemometer, following a standardised method for tubes. In principal the method is simple: measure mean air velocity in the tubular duct with an anemometer and get the flow by multiplying by the duct area.
Figure 12. Dynamic behaviour of the heat exchange coefficient. However, the fact that the ventilation profile in the duct is not uniform complicates the matter somewhat. Following the instructions the method will limit the error to around 4%. The optimum working point for the highest accuracy on the thermal energy that is contained in the air-gap is derived from an extensive error analysis study. It was concluded that for the TRE an air flow of 25 +-3 l/s is within the limits of accuracy. In [Ref 19, 20 and 26] the need for this improvement is discussed in further detail. In figure 12 however the 9
impact of the airflow on the heat transfer coefficient is made visible by simulation output from FLUENT. Recently a further improvement has been made to the TRE-box. The air-inlet has been substituted by 0.1 m2 rectangular opening, over the full width of the air-gap, allowing the flow of air enter the sensitive area behind the PV module without disturbance, creating Air outlet, a more homogenous heat exchange. Airflow measurement point The ambient air temperature near the inlet is measured and compared with the temperature at the entrance of the air-gap behind the PV module to check for pre-heating. Temperature In front of the TRE are mounted two white sensors painted shading devices in order to avoid heating up of the TRE from solar radiation and therewith disturbing the air temperature measurements. See figure 13 for clarification. Note that not all sensors are presented in this figure.
Figure 13. A cross-view of the new TRE. 4. EXPERIMENTAL RESULTS For the here reported case-study a PV module with glass-glass poly-crystalline Si technology was selected. It can be found regular in façade applications. Four equally sized p-Si PV-modules, 120*120 cm, have been used on the TRE. Each module differs from the others for its composition and packing factor. In photo 14 can be seen the experimental set-up for an electrical and thermal performance assessment as was carried out under the Impact project. ♦ A 121 cells glass-glass PV-module; bottom right in the photo ♦ A 64 cells glass-glass PV-module; bottom left in the photo ♦ A 121 cells glass-tedlar PV-module ; top right in the photo ♦ A 121 cells transparent tedlar-glass module; top left in the photo
Photo 14. Thermal image from the four p-Si PV-modules that were used in the experiments The thermal image in photo 14, has been taken 1st of October 2002; the 8-color scale ranges from 31 to 51
10
°C and illustrates nicely the impact of the PV-module composition. The modules are designed specifically for this research project and include specific incorporated cells for the measurement of the short circuit current, the open voltage. See Ref [4, 20] for further information. The PV-module consists of 3 different strings of PV cells allowing the assessment of the required input for analysis. In principle a signal for solar radiation is obtained from the current of one PV-cell connected to a shunt. In the laboratories of the JRC the calibration data for these specific cells, are measured. One particular string of 36 cells was used for open voltage measurement and gives a signal for the temperature of the cell under operating conditions. In addition a temperature sensor has been laminated in the module. Outdoor measurements are made to obtain specific data from environmental conditions, including wind and thermal measurements. Two strings of 36 cells are connected in series (72 cells are similar to a 100 Wp module) and connected to a Maximum Power Point inverter. The experiments have been performed with forced airflow at four different levels of air flow rate. The ventilator speed settings correspond to measured air velocity in the outlet tube and air flow mass (required as input to MainType83 as follow: Ventilator speed settings
air velocity [m/s]
Air flow mass [m3/h m]
6
1.37
129.9
7
1.75
164.7
10
2.49
234.9
13
3.43
323.1
In figure 15 are graphically presented the thermal efficiencies for the glass-glass PV-module for the four different forced ventilation settings.
Figure 15. Thermal efficiency of the 121 cell glass-glass module Some conclusions can be made from the analysis of the experimental data collected. For increasing values of air flow in the TRE air-gap it is possible to observe an: ♦ increase of the thermal efficiency of the system; ♦ increase of the electric efficiency of the system; ♦ decrease of the values of Tair,outlet-Tair,inlet. It is also possible to observe that: ♦ the glass-glass 64 cells PV-module presents the highest values of thermal efficiency in respect to other modules; 11
♦ ♦
the glass-glass 121 cells PV-module presents the worst electric behaviour in operating condition in respect to the electric efficiency obtained in laboratory; the electric efficiency of the glass-tedlar PV-module is better than tedlar-glass one.
5. MODEL DEVELOPMENT The development of a calculation model, able to predict the performances of a ventilated PV facade is based on the definition of equations describing the energy flows, both thermal and electrical, that take place in the PV hybrid system.
Figure 16. Thermal energy exchanges in a PV hybrid system. Some hypothesis has been made before beginning this treatment: 1. the thermal capacity effects have not been considered (hypothesis of quite- stationary state); 2. heat transfer within the system has can be considered as a one-dimensional heat flow; 3. the convective heat exchange between the surfaces of the gap an the air flowing in is considered in the integral shape; 4. the air flow is assumed known. Under this hypothesis the air-gap system could be represented by an electrical resistances model.
Figure 17. Electrical resistances model for a PV transparent double skin facade.
12
5.1 Energy Balance The analysis of the electrical scheme leads to the following equations of energy balance: 1. energy balance for the air gap •
m cp (ϑout −ϑ f ) = Ahcv1 (ϑse −ϑint ) + Ahcv2 (ϑsi −ϑint ) 2. energy balance for the external surface of the air gap
3. energy balance for the internal surface of the air gap
where α is the solar absorbance of different materials (glass, PV layer …), η is the PV efficiency (function of cell temperature and solar irradiance), N are distribution factors for theradiation diffusely absorbed by PV module. θint is the temperature of air in the channel calculated as integral average:
The solution of the previous equations brings to the definition of θse, θsi and θint. It is also possible to calculate θout, the air temperature at the top of the air-gap, having in this way a valuation of the generated thermal energy; the electrical power is calculated from the product of η(Tpv,G) and the incident irradiation on the PV-cell surface. The mathematical equations have been translated into a calculation code [Ref 27] using FORTRAN in order to generate an executable program that could be inserted in the library of the TRNSYS simulation software. Using TRNSYS’s definition it has been called Type83. A MainType 83 program has been generated also that allows the use of Type83 in stand alone mode, thus without the TRNSYS environment. Parameters requested by MainType83 are: − geographic parameters (location); − geometric parameters; − thermal properties; − optical properties; − parameter describing properties of PV elements inserted in the wall; − parameter describing the kind of double skin wall studied. Input parameters required are: − air temperature; − operating temperature of internal environment of the building; − air flow; −solar irradiation on Horizontal surface; −external relative humidity. The main output given by the code are: − surfaces temperatures; − PV cell temperature; − temperature of heated air leaving the gap; − electric power generated by the PV system; − thermal power generated; − energy flows crossing the wall. 5.2 Validation and calibration of the model The MainType has been applied to a configuration describing the TRE physical structure, in order to have an evaluation of the validity of results produced by the code. The input given to MainType 83 are the
13
climatic data collected in Ispra and the air flow measured in the TRE air-gap. The output signals are Tse the external surface temperature of the gap, Tsi the internal surface temperature, Tcell the PV-cell temperature, Tout the air temperature at the outlet of the TRE air-gap, Wel electric power generated by the inverter. To assess an error of the calculation model a comparison between collected data and calculated results has been done for each of the four PV-modules applied and for each of the four levels of air flow rate. A first result for MainType83 shows that: Tsurfaces,calculated > Tsurfaces,measured Tout,calculated < Tout,measured The conclusion was made that the developed model under estimates the convective heat exchange between surfaces and air flow in the air-gap because of not correct correlations describing the convective heat exchange coefficient hcv. In order to investigate and to solve this problem a three-dimensional model of the TRE air-gap has been developed using FLUENT 6.0.2 software. The input data given to this model are the measured data from the TRE (Tse, Tsi, Tout, and the air flow). The three-dimensional model allows studying the fluid dynamic behaviour inside the TRE air-gap and it provided useful information to estimate correct values for the heat exchange coefficient hcv.
Figures 18, 19. Three-dimensional model of TRE duct and description of air velocity vectors. It has been concluded that in particular the geometric configuration of the connection between the air inlet tube and the TRE air-gap (elbow connection and section’s expansion) creates strong local turbulences that forces a sensible local increase of hcv. See also figures 18 and 19. From literature study and simulation with FLUID an adjusted heat exchange coefficient hcv for this set-up has been defined. As a result the model output improved. The model shows a good agreement with the measured values for Tse and Tpv. A disagreement can be found on Tsi; nevertheless this could not be considered a real error in fact it could be observed that this behaviour is generated by a time advance of Tsi, calculated on Tsi,measured. This depends from the fact that (small) thermal capacity effects have not been taken into account. This approach can be considered correct for a double skin facade (composed of a “light” frame). But the TRE has an internal opaque surface whose thermal capacity couldn’t fully be neglected. This effect is very weak on the PV-module, as by hypothesis for light frame. The behaviour observed on Tsi influences also Tout, where it is possible to observe a similar time translation between measured data a model results.
14
Figure 20. Calculated and measured electrical output during a specific sunny day. When it concerns the electricity generated by the system, the energy output predicted by the model is in good accordance with the measured one. An error less than 5% for the daily energy production is achievable. 6. CONCLUSION The work carried out by a number of research organisation, most of them Paslink members, over the last ten years in several European projects have improved the understanding of the complex interaction of PV technology with the building boundary conditions. It is expected that this expertise will be needed in the near future when PV and construction industry will focus on true integration of the PV technology in the built environment. Meanwhile the established research organisations should continue in developing and improving performance assessment procedures including experimental set-ups, calculation methods, modelling and design tools. Further developments for both the experimental and modelling work should be made in relation to solar energy technology as required by the Energy Performance Directive for Buildings. The definition of an improved and standard Test Reference Environment for BIPV applications has to be made in the near future. This new structure will have to be based on the results from this study. The experimental work will produce data for the validation of calculation models for BIPV applications that are expected to become more frequent in the coming years. REFERENCES [1] Wouters P., Vandaele L., Bloem H. “Hybrid Photovoltaic Building Facades: The Challenges for an integrated overall Performance Evaluation”. In the Proceedings of the Conference on “Solar Energy in Architecture and Urban Planning”, Berlin 26-29 March (1996). [2] L. Vandaele, P Wouters, J. J. Bloem, W.J. Zaaiman, “Combined heat and power from hybrid photovoltaic building integrated components: results from overall performance assessment.”, Proc. 2nd World Conference and Exhibition on Photovoltaic Solar Energy Conversion, Vienna (1998). [3] J. R. Bates, U. Blieske, J.J. Bloem, J Campbell, F. Ferrazza, R. J. Hacker, P. Strachan, Y.Tripanagnostopoulos, “Building Implementation of Photovoltaics with Active Control of Temperature, ‘Building IMPACT’ – Final Results” Proceedings of the 17th PV Conference, Muenchen (Oct 2001). [4] J.J. Bloem, W. Zaaiman, C. Bucci, V.R. Nacci. "Proposal for a PV Reference Module and a Test Reference Environment for BIPV Applications". Proceedings of the 16th PV Conference, Glasgow (2000). [5] M. van Schalkwijk et al. "PRESCRIPT - Towards a European standardisation of PV building
15
[6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]
[17] [18] [19] [20] [21] [22] [23] [24]
[25] [26] [27]
components". Proc. 2nd World Conference and Exhibition on Photovoltaic Solar Energy Conversion, Vienna (1998). PV Cool Build – A design guide; EC – FP5 project NNE5/2000/115. www.pvcoolbuild.com Nordmann T. Built-in Future. Renewable Energies Vol 8, no 4, 236-247 (2005). Jäger-Waldau A. (ed.). (2004) Status Report 2004; Energy End-use Efficiency and Electricity from Biomass, Wind and Photovoltaics in the European Union. EUR 21297 EN (2004). IEA PVPS Task 7; Photovoltaics in the Built Environment. Extract published in Renewable Energies Vol 8, no 3, 140-149 (2005). EPIA and Greenpeace (2004). The Solar Generation report. DIRECTIVE 2001/77/EC Promotion of electricity produced from Renewable Energy Sources in the internal electricity market. DIRECTIVE 2002/91/EC on the Energy Performance of Buildings. Bloem J.J. Overcome barriers for private investment into photovoltaic in the residential built environment. 20th PV Conference, 6-11 June 2005, Barcelona. Bloem J.J., Baker P.H. ”Building Integration Issues for Photovoltaics ". In the Proceedings of BIAT Technical Innovation in Design and Contruction - Dublin Castle, 23-24 November 2000. Bloem J.J., Baker P.H. Strachan P.A. Energy Performance of Buildings and the Integration of Photovoltaics. EECB Conference, Frankfurt (2004). Bloem J.J., Baker P.H. Strachan P.A. (2000). PV Solar Systems in the Built Environment; Specific requirements for Integration, Energy Monitoring, Analysis and Control. 6th European Conference : Solar Energy in Architecture and Urban Planning, Bonn (2000). Bloem J.J., Baker P.H., Stirling C. PV Systems and specific requirements for Building Integration. Proceedings of the 16th PV Conference, Glasgow (2000). IEC 1215 (1993), Crystalline silicon terrestrial photovoltaic (PV) modules – Design qualification and type approval. A. Gandini. “Analisi numerica delle facciate fotovoltaiche a ‘doppia pell’”, Politecnico di Milano (2003). J.J. Bloem, “BIPV Case Study for modelling and analysis”. Proceedings of the DAME Conference, 13-14 November, Ispra (2003). J.J. Bloem, R. van Dijk. “The PV module considered from an energy flow perspective”. To be presented at the 16th PV Conference, Glasgow (2000). D. van Dijk, R. Versluis, PV-HYBRID-PAS: Results of Thermal Performance Assessment, Proceedings 2nd World Conference on Photovoltaic Solar Energy Conversion, Vienna, (1998). Bloem J.J., Jäger-Waldau A., Colli A.(2005) Economic Analysis Of Photovoltaic Shading Devices In The Mediterranean Built Environment. 20th PV Conference, 6-11 June 2005, Barcelona. L. Vandaele, A Deneyer, N. Heijmans, F.Dobbels. (May 2005). Innovative low energy renovation of a single family dwelling for summer comfort. PALENC Conference, Santorini, Greece (19-21 May, 2005). Bloem J.J., Colli A., Strachan P.A. Evaluation of PV implementation in the Building Sector. PALENC Conference, Santorini, Greece (19-21 May, 2005). Numerical analysis of PV double skin facades. Proceedings of the DAME Conference, 13-14 November, Ispra (2003). Bloem J.J., Gandini A., Mazzarella L., A TRNSYS Type Calculation Model for Double Skin Photovoltaic Facades. Workshop on Dynamic Analysis Methods applied to Energy Performance Assessment of Buildings, Warsaw, Poland (13-14 May 2004).
16
