Measured Versus Predicted Performance of Building Integrated Photovoltaics

2003 ◽  
Vol 125 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Mark W. Davis ◽  
A. Hunter Fanney ◽  
Brian P. Dougherty
Keyword(s):  
Meteorological Data ◽  
Silicon Film ◽  
Rear Surface ◽  
Predictive Performance ◽  
Performance Data ◽  
Test Bed ◽  
Photovoltaic Panels ◽  
Building Integrated Photovoltaics ◽  
Curve Tracer ◽  
Building Integrated Photovoltaic

The lack of predictive performance tools creates a barrier to the widespread use of building integrated photovoltaic panels. The National Institute of Standards and Technology (NIST) has created a building integrated photovoltaic (BIPV) test bed to capture experimental data that can be used to improve and validate previously developed computer simulation tools. Twelve months of performance data have been collected for building integrated photovoltaic panels using four different cell technologies—crystalline, polycrystalline, silicon film, and triple-junction amorphous. Two panels using each cell technology were present, one without any insulation attached to its rear surface and one with insulation having a nominal thermal resistance value of 3.5m2s˙K/W attached to its rear surface. The performance data associated with these eight panels, along with meteorological data, were compared to the predictions of a photovoltaic model developed jointly by Maui Solar Software and Sandia National Laboratories (SNL), which is implemented in their IV Curve Tracer software [1]. The evaluation of the predictive performance tools was done in the interest of refining the tools to provide BIPV system designers with a reliable source for economic evaluation and system sizing.

Measured Versus Predicted Performance of Building Integrated Photovoltaics

Solar Energy ◽  
2002 ◽  
Author(s):  
Mark W. Davis ◽  
A. Hunter Fanney ◽  
Brian P. Dougherty
Keyword(s):  
Meteorological Data ◽  
Silicon Film ◽  
Rear Surface ◽  
Predictive Performance ◽  
Performance Data ◽  
Test Bed ◽  
Photovoltaic Panels ◽  
Building Integrated Photovoltaics ◽  
Curve Tracer ◽  
Building Integrated Photovoltaic

The lack of predictive performance tools creates a barrier to the widespread use of building integrated photovoltaic panels. The National Institute of Standards and Technology (NIST) has created a building integrated photovoltaic (BIPV) “test bed” to capture experimental data that can be used to improve and validate previously developed computer simulation tools. Twelve months of performance data have been collected for building integrated photovoltaic panels using four different cell technologies – crystalline, polycrystalline, silicon film, and triple-junction amorphous. Two panels using each cell technology were present, one without any insulation attached to its rear surface and one with insulation having a nominal thermal resistance value of 3.5 m2·K/W attached to its rear surface. The performance data associated with these eight panels, along with meteorological data, were compared to the predictions of a photovoltaic model developed jointly by Maui Solar Software and Sandia National Laboratories (SNL), which is implemented in their IV Curve Tracer software [1]. The evaluation of the predictive performance tools was done in the interest of refining the tools to provide BIPV system designers with a reliable source for economic evaluation and system sizing.

Measured Performance of Building Integrated Photovoltaic Panels*

2001 ◽  
Vol 123 (3) ◽  
pp. 187-193 ◽  
Author(s):  
A. Hunter Fanney ◽  
Brian P. Dougherty ◽  
Mark W. Davis
Keyword(s):  
Amorphous Silicon ◽  
Thermal Insulation ◽  
Photovoltaic Cells ◽  
Performance Data ◽  
Average Growth ◽  
Single Crystalline ◽  
Photovoltaic Panels ◽  
Building Integrated Photovoltaics ◽  
Cell Technologies ◽  
Building Integrated Photovoltaic

The photovoltaic industry is experiencing rapid growth. Industry analysts project that photovoltaic sales will increase from their current $1.5 billion level to over $27 billion by 2020, representing an average growth rate of 25%. (Cook et. al. 2000)[1]. To date, the vast majority of sales have been for navigational signals, call boxes, telecommunication centers, consumer products, off-grid electrification projects, and small grid-interactive residential rooftop applications. Building integrated photovoltaics, the integration of photovoltaic cells into one or more of the exterior surfaces of the building envelope, represents a small but growing photovoltaic application. In order for building owners, designers, and architects to make informed economic decisions regarding the use of building integrated photovoltaics, accurate predictive tools and performance data are needed. A building integrated photovoltaic test bed has been constructed at the National Institute of Standards and Technology to provide the performance data needed for model validation. The facility incorporates four identical pairs of building integrated photovoltaic panels constructed using single-crystalline, polycrystalline, silicon film, and amorphous silicon photovoltaic cells. One panel of each identical pair is installed with thermal insulation attached to its rear surface. The second paired panel is installed without thermal insulation. This experimental configuration yields results that quantify the effect of elevated cell temperature on the panels’ performance for different cell technologies. This paper presents the first set of experimental results from this facility. Comparisons are made between the electrical performance of the insulated and non-insulated panels for each of the four cell technologies. The monthly and overall conversion efficiencies for each cell technology are presented and the seasonal performance variations discussed. Daily efficiencies are presented for a selected month. Finally, plots of the power output and panel temperatures are presented and discussed for the single-crystalline and amorphous silicon panels.

Measured Performance of Building Integrated Photovoltaic Panels

2001 ◽  
Author(s):  
A. Hunter Fanney ◽  
Brian P. Dougherty ◽  
Mark W. Davis
Keyword(s):  
Amorphous Silicon ◽  
Thermal Insulation ◽  
Photovoltaic Cells ◽  
Performance Data ◽  
Average Growth ◽  
Single Crystalline ◽  
Photovoltaic Panels ◽  
Building Integrated Photovoltaics ◽  
Cell Technologies ◽  
Building Integrated Photovoltaic

Abstract The photovoltaic industry is experiencing rapid growth. Industry analysts project that photovoltaic sales will increase from their current $1.5 billion level to over $27 billion by 2020, representing an average growth rate of 25% [1]. To date, the vast majority of sales have been for navigational signals, call boxes, telecommunication centers, consumer products, off-grid electrification projects, and small grid-interactive residential rooftop applications. Building integrated photovoltaics, the integration of photovoltaic cells into one of more of the exterior surfaces of the building envelope, represents a small but growing photovoltaic application. In order for building owners, designers, and architects to make informed economic decisions regarding the use of building integrated photovoltaics, accurate predictive tools and performance data are needed. A building integrated photovoltaic test bed has been constructed at the National Institute of Standards and Technology to provide the performance data needed for model validation. The facility incorporates four identical pairs of building integrated photovoltaic panels constructed using single-crystalline, polycrystalline, silicon film, and amorphous silicon photovoltaic cells. One panel of each identical pair is installed with thermal insulation attached to its rear surface. The second paired panel is installed without thermal insulation. This experimental configuration yields results that quantify the effect of elevated cell temperature on the panels’ performance for different cell technologies. This paper presents the first set of experimental results from this facility. Comparisons are made between the electrical performance of the insulated and non-insulated panels for each of the four cell technologies. The monthly and overall conversion efficiencies for each cell technology are presented and the seasonal performance variations discussed. Daily efficiencies are presented for a selected month. Finally, hourly plots of the power output and panel temperatures are presented and discussed for the single-crystalline and amorphous silicon panels.

Building Integrated Photovoltaic Test Facility*

2001 ◽  
Vol 123 (3) ◽  
pp. 194-199 ◽  
Author(s):  
A. Hunter Fanney ◽  
Brian P. Dougherty
Keyword(s):  
Building Envelope ◽  
Meteorological Station ◽  
Test Facility ◽  
Solar Photovoltaic ◽  
Test Bed ◽  
Manufacturing Costs ◽  
Experimental Performance ◽  
Building Integrated Photovoltaics ◽  
Building Integrated Photovoltaic ◽  
The U.S

The widespread use of building integrated photovoltaics appears likely as a result of the continuing decline in photovoltaic manufacturing costs, the relative ease in which photovoltaics can be incorporated within the building envelope, and the fact that buildings account for over 40% of the U.S. energy consumption. However, designers, architects, installers, and consumers need more information and analysis tools in order to judge the merits of building-integrated solar photovoltaic products. In an effort to add to the knowledge base, the National Institute of Standards and Technology (NIST) has undertaken a multiple-year project to collect high quality experimental performance data. The data will be used to validate computer models for building integrated photovoltaics and, where necessary, to develop algorithms that may be incorporated within these models. This paper describes the facilities that have been constructed to assist in this effort. The facilities include a mobile tracking photovoltaic test facility, a building integrated photovoltaic test bed, an outdoor aging rack, and a meteorological station.

Prediction of Building Integrated Photovoltaic Cell Temperatures*

2001 ◽  
Vol 123 (3) ◽  
pp. 200-210 ◽  
Author(s):  
Mark W. Davis ◽  
A. Hunter Fanney ◽  
Brian P. Dougherty
Keyword(s):  
Heat Transfer ◽  
Environmental Conditions ◽  
Solar Irradiance ◽  
Operating Temperature ◽  
Predictive Performance ◽  
Transfer Model ◽  
Cell Temperature ◽  
Widespread Application ◽  
Building Integrated Photovoltaics ◽  
Building Integrated Photovoltaic

A barrier to the widespread application of building integrated photovoltaics (BIPV) is the lack of validated predictive performance tools. Architects and building owners need these tools in order to determine if the potential energy savings realized from building integrated photovoltaics justifies the additional capital expenditure. The National Institute of Standards and Technology (NIST) seeks to provide high quality experimental data that can be used to develop and validate these predictive performance tools. The temperature of a photovoltaic module affects its electrical output characteristics and efficiency. Traditionally, the temperature of solar cells has been characterized using the nominal operating cell temperature (NOCT), which can be used in conjunction with a calculation procedure to predict the module’s temperature for various environmental conditions. The NOCT procedure provides a representative prediction of the cell temperature, specifically for the ubiquitous rack-mounted installation. The procedure estimates the cell temperature based on the ambient temperature and the solar irradiance. It makes the approximation that the overall heat loss coefficient is constant. In other words, the temperature difference between the panel and the environment is linearly related to the heat flux on the panels (solar irradiance). The heat transfer characteristics of a rack-mounted PV module and a BIPV module can be quite different. The manner in which the module is installed within the building envelope influences the cell’s operating temperature. Unlike rack-mounted modules, the two sides of the modules may be subjected to significantly different environmental conditions. This paper presents a new technique to compute the operating temperature of cells within building integrated photovoltaic modules using a one-dimensional transient heat transfer model. The resulting predictions are compared to measured BIPV cell temperatures for two single crystalline BIPV panels (one insulated panel and one uninsulated panel). Finally, the results are compared to predictions using the NOCT technique.

Prediction of Building Integrated Photovoltaic Cell Temperatures

2001 ◽  
Author(s):  
Mark W. Davis ◽  
A. Hunter Fanney ◽  
Brian P. Dougherty
Keyword(s):  
Heat Transfer ◽  
Environmental Conditions ◽  
Solar Irradiance ◽  
Operating Temperature ◽  
Predictive Performance ◽  
Transfer Model ◽  
Cell Temperature ◽  
Widespread Application ◽  
Building Integrated Photovoltaics ◽  
Building Integrated Photovoltaic

Abstract A barrier to the widespread application of building integrated photovoltaics (BIPV) is the lack of validated predictive performance tools. Architects and building owners need these tools in order to determine if the potential energy savings realized from building integrated photovoltaics justifies the additional capital expenditure. The National Institute of Standards and Technology (NIST) seeks to provide high quality experimental data that can be used to develop and validate these predictive performance tools. The temperature of a photovoltaic module affects its electrical output characteristics and efficiency. Traditionally, the temperature of solar cells has been characterized using the nominal operating cell temperature (NOCT), which can be used in conjunction with a calculation procedure to predict the module’s temperature for various environmental conditions. The NOCT procedure provides a representative prediction of the cell temperature, specifically for the ubiquitous rack-mounted installation. The procedure estimates the cell temperature based on the ambient temperature and the solar irradiance. It makes the approximation that the overall heat loss coefficient is constant. In other words, the temperature difference between the panel and the environment is linearly related to the heat flux on the panels (solar irradiance). The heat transfer characteristics of a rack-mounted PV module and a BIPV module can be quite different. The manner in which the module is installed within the building envelope influences the cell’s operating temperature. Unlike rack-mounted modules, the two sides of the modules may be subjected to significantly different environmental conditions. This paper presents a new technique to compute the operating temperature of cells within building integrated photovoltaic modules using a one-dimensional transient heat transfer model. The resulting predictions are compared to measured BIPV cell temperatures for two single crystalline BIPV panels (one insulated panel and one uninsulated panel). Finally, the results are compared to predictions using the NOCT technique.

Short-Term Characterization of Building Integrated Photovoltaic Panels

Solar Energy ◽  
2002 ◽  
Author(s):  
A. Hunter Fanney ◽  
Mark W. Davis ◽  
Brian P. Dougherty
Keyword(s):  
Silicon Film ◽  
Simulation Models ◽  
Electrical Performance ◽  
Test Procedures ◽  
Simulation Tools ◽  
Building Integrated Photovoltaics ◽  
Economic Decisions ◽  
Experimental Apparatus ◽  
Building Integrated Photovoltaic ◽  
Building Surfaces

Building integrated photovoltaics, the integration of photovoltaic cells into one or more exterior building surfaces, represents a small but growing part of today’s $2 billion dollar photovoltaic industry. A barrier to the widespread use of building integrated photovoltaics (BIPV) is the lack of validated predictive simulation tools needed to make informed economic decisions. The National Institute of Standards and Technology (NIST) has undertaken a multi-year project to compare the measured performance of BIPV panels to the predictions of photovoltaic simulation tools. The existing simulation models require input parameters that characterize the electrical performance of BIPV panels subjected to various meteorological conditions. This paper describes the experimental apparatus and test procedures used to capture the required parameters. Results are presented for custom fabricated mono-crystalline, polycrystalline, and silicon film BIPV panels and a commercially available triple junction amorphous silicon panel.

Short-Term Characterization of Building Integrated Photovoltaic Panels*

2003 ◽  
Vol 125 (1) ◽  
pp. 13-20 ◽  
Author(s):  
A. Hunter Fanney ◽  
Brian P. Dougherty ◽  
Mark W. Davis
Keyword(s):  
Silicon Film ◽  
Simulation Models ◽  
Electrical Performance ◽  
Test Procedures ◽  
Simulation Tools ◽  
Building Integrated Photovoltaics ◽  
Economic Decisions ◽  
Experimental Apparatus ◽  
Building Integrated Photovoltaic ◽  
Building Surfaces

Building integrated photovoltaics, the integration of photovoltaic cells into one or more exterior building surfaces, represents a small but growing part of today’s $2 billion dollar photovoltaic industry. A barrier to the widespread use of building integrated photovoltaics (BIPV) is the lack of validated predictive simulation tools needed to make informed economic decisions. The National Institute of Standards and Technology (NIST) has undertaken a multi-year project to compare the measured performance of BIPV panels to the predictions of photovoltaic simulation tools. The existing simulation models require input parameters that characterize the electrical performance of BIPV panels subjected to various meteorological conditions. This paper describes the experimental apparatus and test procedures used to capture the required parameters. Results are presented for custom fabricated mono-crystalline, polycrystalline, and silicon film BIPV panels and a commercially available triple junction amorphous silicon panel.

scholarly journals Numerical analysis of the efficiency and energy production of the building integrated photovoltaics for various configurations

2019 ◽  
Vol 111 ◽  
pp. 03044
Author(s):  
Sebastian Valeriu Hudișteanu ◽  
Cătalin George Popovici
Keyword(s):  
Operating Temperature ◽  
Photovoltaic System ◽  
Vertical Position ◽  
Pv System ◽  
Photovoltaic Panel ◽  
Photovoltaic Panels ◽  
Building Integrated Photovoltaics ◽  
Building Integrated Photovoltaic ◽  
Unit Surface ◽  
Continental Climate

The paper presents the analysis of the building integrated photovoltaic panels (BIPV) realized for the same photovoltaic system, placed in different locations, for the continental climate of Romania. For all studied cases, the photovoltaic (PV) system is examined in various vertical configurations, considering the integration into buildings placed in urban agglomerations, characterized by small horizontal surfaces, but generous facades. For the analyzed situations it is assumed that the PV panels are fixed in vertical position. Therefore, one of the possibilities of raising their efficiency consists in controlling the operating temperature of the photovoltaic cells. The operating parameters of the photovoltaic panels are studied in case of integration at 10 m height above the ground and the results are reported on the unit surface. The model and the functioning parameters are processed using TRNSYS software. The results are analyzed for average daily, monthly and yearly values. The results reveal some major differences obtained for the same system placed in different locations or orientations. The average efficiencies for maximum production months are lower than annual ones, while the daily values for efficiency are lowest. These values are directly dependent on the intensity of solar radiation and are negatively influenced by the operating temperature of the photovoltaic panel.

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