To make it easier to use the Building Integrated PV (BIPV) as a glazing, a group within the IEA Photovoltaic Power Systems Program (IEA-PVPPS) has tackled the calculation of the solar support coefficient (SHGC) for BIPV. It is part of IA PVPS task 15 international standardization -efforts.
Het laatste rapport van Task 15, een wereldwijde project ingesteld om barrières aan te pakken met betrekking tot het bouwen van geïntegreerde PV (BIPV) door het IEA Photovoltaic Power Systems Program (IEA-PVPPS), biedt een experimenteel gebaseerde manier om Solar Heat Gain Coëfficiënt (SHGC) te bepalen, ook bekend als “G-waarde” en hoe normen kunnen worden aangepast aan de manier waarop It is calculated in BIPV products.
The SHGC usually quantifies how much incident solar radiation, directly or indirectly is transferred by components of building and converted into heat. There is a need to change it for BIPV, because PV current generation reduces absorbed solar energy that would otherwise be transferred as heat in interior spaces.
“Insight into this effect is essential for optimizing energy efficiency in buildings, reducing the cooling demand and supporting the wider acceptance of BIPV solutions,” said Task 15 team.
The report, “Solar heat winning coefficient of BIPV modules for electricity-generating facades“Presents research into SHGC, an important statistics for conventional architectural glazing to calculate the cooling question of construction. Two complementary approaches have been proposed. One trusts to adjust an internationally standardized calorimetric measurement of the SHGC, which is purchasing, depending on the PV cell coverage and the thermal properties of the glazing, taking into account what happens when electricity is generated and extracted during the measurement.
The other approach is to calculate the SHGC of the glazing from the optical and thermal properties of its components and the photovoltaic conversion efficiency of the module. It adjusts the international standards for conventional glazing to take into account the typical characteristics of BIPV, such as the optical inhomogenity caused by the coverage of the solar cell and the generation of electricity, according to the team.
Both proposals were the result of pre-normative research by members of task 15 and were recently published in Energy and buildings: ‘Components-based SHGC determination of BIPV blazing for product comparison“And”International Inter-Laboratory comparison of solar heat profit-to-tabo of building-integrated photovoltaic modules results of tests with or without electricity generation and tests with PV-cell clothing ratios. “
In the meantime, changes in international standards based on the research results have been proposed and are currently in the public research phase.
“These changes make improved comparability and accuracy possible with the SHGC assessment of BIPV blazing units,” the team said.
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