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.

Cooling of Concentrator Photovoltaic Cells Using Mini-Scale Jet Impingement Heat Sinks

2018 ◽  
Author(s):  
Ali Radwan ◽  
Meshack Hawi ◽  
Mahmoud Ahmed
Keyword(s):  
Heat Transfer ◽  
Flow Model ◽  
Three Dimensional ◽  
Jet Impingement ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Transfer Model ◽  
Cell Temperature ◽  
Maximum Cell ◽  
T System

In this study, an efficient cooling technique for concentrator photovoltaic (CPV) cells is proposed to enhance the system electrical efficiency and extend its lifetime. To do this, a comprehensive three-dimensional conjugate heat transfer model of CPV cells layers coupled with the heat transfer and fluid flow model inside jet impingement heat sink is developed. Four different jet impingement designs are compared. The investigated designs are (A) central inlet jet, (B) Hypotenuse inlet jet, (C) staggered inlet jet, and (D) conventional jet impingement design with side drainage. The effect of coolant flowrate on the CPV/T system performance is investigated. The model is numerically simulated and validated using the available experiments. The performance of CPV system is investigated at solar concentration ratios of 20 and coolant flowrate up to 6000g/min. It is found that increasing the flowrate from 60 g/min to 600 g/min decrease the maximum cell temperature by 31°C for the configuration D while increasing the flowrate from 600 g/min to 6000 g/min reduce the cell temperature by 20.2°C. It is also concluded that at a higher flowrate of 6000g/min, all the investigated configurations relatively achieve better temperature uniformity with maximum temperature differences of 0.9 °C, 2.1 °C, 3.6 °C, and 3.9 °C for configurations A, B, C, and D respectively.

scholarly journals An analysis of temperature distribution in solar photovoltaic module under various environmental conditions

2018 ◽  
Vol 240 ◽  
pp. 04004 ◽  
Author(s):  
Marek Jaszczur ◽  
Qusay Hassan ◽  
Janusz Teneta ◽  
Ewelina Majewska ◽  
Marcin Zych
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Wind Speed ◽  
Solar Radiation ◽  
Environmental Conditions ◽  
Operating Temperature ◽  
Photovoltaic Module ◽  
Solar Photovoltaic ◽  
System Efficiency ◽  
Pv System

The operating temperature of the photovoltaic module is an important issue because it is directly linked with system efficiency. The objective of this work is to evaluate temperature distribution in the photovoltaic module under different environmental conditions. The results shown that photovoltaic module operating temperature depends not only on the ambient temperature or solar radiation dependent but also depends on wind speed and wind direction. It is presented that the mounting conditions which are not taken into consideration by most of the literature models also play a significant role in heat transfer. Depends on mounting type an increase in module operating temperature in the range 10-15oC was observed which cause further PV system efficiency decrease of about 3.8-6.5 %.

Modeling, Testing, and Evaluation of a Building-Integrated Photovoltaic-Thermal Collector

2009 ◽  
Author(s):  
Charles D. Corbin ◽  
Michael J. Brandemuehl
Keyword(s):  
Heat Transfer ◽  
Thermal Efficiency ◽  
Low Cost ◽  
Convection Heat Transfer ◽  
Calibration Error ◽  
Transfer Model ◽  
Transfer Coefficients ◽  
Electrical Efficiency ◽  
Building Integrated Photovoltaic ◽  
Low Efficiency

The performance of Building-Integrated Photovoltaic-Thermal (BIPV/T) collector is examined in this study. A full scale-test collector is monitored over several weeks in the summer of 2008 and measured data is used to calibrate a heat transfer model implemented in a common scientific computing software package. Following calibration, error between experimental measurements and the calibrated model outputs is within the limits of measurement uncertainty. Collector simulations are constructed to examine thermal efficiency, the effectiveness of the collector as a night-sky radiator, the effect of heat collection on electrical efficiency, the effect of two common exterior convection coefficients on collector performance, and the effect of eliminating the air gap between the PV and absorber surfaces. Overall collector thermal efficiency is relatively low compared to existing collectors. However, the potential low cost of the system could allow larger collector areas to compensate for low efficiency, especially in warm climates. Combined thermal and electrical efficiency can be as high as 34%. Additional analysis also indicates that the predicted thermal performance is highly dependent on the thermal resistance between the PV cells and the absorber plate and is sensitive to assumptions regarding wind-driven convection heat transfer coefficients.

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.

Applicability of Heat Mirrors in Reducing Thermal Losses in Concentrating Solar Collectors

2016 ◽  
Author(s):  
Prashant Mahendra ◽  
Vikrant Khullar ◽  
Madhup Mittal
Keyword(s):  
Heat Transfer ◽  
Thermal Efficiency ◽  
Solar Irradiance ◽  
Solar Collector ◽  
Flux Distribution ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
Solar Collectors ◽  
Parabolic Trough ◽  
Glass Envelope

Flux distribution around the parabolic trough receiver being typically non-uniform, only a certain portion of the receiver circumference receives the concentrated solar irradiance. However, radiative and convective losses occur across the entire receiver circumference. This paper attempts to introduce the idea employing transparent heat mirror to effectively reduce the heat loss area and thus improve the thermal efficiency of the solar collector. Transparent heat mirror essentially has high transmissivity in the solar irradiance wavelength band and high reflectivity in the mid-infrared region thus it allows the solar irradiance to pass through but reflects the infrared radiation back to the solar selective metal tube. Practically, this could be realized if certain portion of the conventional low iron glass envelope is coated with Sn-In2O3 so that its acts as a heat mirror. In the present study, a parabolic receiver design employing the aforesaid concept has been proposed. Detailed heat transfer model has been formulated. The results of the model were compared with the experimental results of conventional concentrating parabolic trough solar collectors in the literature. It was observed that while maintaining the same external conditions (such as ambient/initial temperatures, wind speed, solar insolation, flow rate, concentration ratio etc.) the heat mirror-based parabolic trough concentrating solar collector has about 3–12% higher thermal efficiency as compared to the conventional parabolic solar collector. Furthermore, steady state heat transfer analysis reveals that depending on the solar flux distribution there is an optimum circumferential angle (θ = θoptimum, where θ is the heat mirror circumferential angle) up to which the glass envelope should be coated with Sn-In2O3. For angles higher than the optimum angle, the collector efficiency tends to decrease owing to increase in optical losses.

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.

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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