The International Energy Agency’s (IEA) Photovoltaic Power Systems Programme (IEA-PVPS) has been working to address the challenges of building-integrated photovoltaic (BIPV) systems, specifically the calculation of the solar heat gain coefficient (SHGC). The SHGC is a crucial metric for determining how much solar radiation is transmitted and converted into heat through building envelope components. However, BIPV systems pose a unique challenge due to the reduction of absorbed solar energy that would otherwise be converted into heat.
To tackle this issue, a group within the IEA-PVPS, Task 15, has aimed to develop an experimentally-based method for calculating SHGC for BIPV systems. The team proposes two complementary approaches: adapting an internationally standardized calorimetric measurement and calculating the SHGC based on the optical and thermal properties of the BIPV glazing and its photovoltaic conversion efficiency.
The research, published in the journal Energy and Buildings, presents two papers that outline the two approaches. The team also suggests modifying international standards to account for the unique characteristics of BIPV glazing, such as optical inhomogeneity caused by solar cell coverage and electricity generation.
The proposed modifications to international standards are currently in the public inquiry phase, aiming to improve the comparability and accuracy of SHGC assessments for BIPV glazing units. The goal is to make it easier for developers to incorporate BIPV systems into their designs, ultimately promoting energy efficiency and reducing cooling demands. By addressing the specific challenges associated with SHGC calculation for BIPV systems, the industry can move closer to widespread adoption of these innovative and sustainable solutions.