Effect of Solar Cell Materials on Energy Matrices of GISPVT System

This paper  presents an analytical expression for the temperatures of the plant, room air, and solar cell, as well as the electrical efficiency, for a photo-voltaic thermal (PVT) roof façade of a greenhouse integrated semi-transparent photovoltaic thermal (GiSPVT) system. The expression considers climatic variables such as solar intensity and ambient air temperature, as well as design parameters such as the area of the PV module, electrical efficiency under standard test conditions (STC), temperature coefficient, and various heat transfer coefficients. Using monthly numerical computations for different parameters in Indian climatic conditions, this study evaluates energy matrices such as energy payback time (EPBT), energy production factor (EPF), and life cycle conversion efficiency (LCCE) for various solar cell materials, including single-crystalline (c-Si), multi-crystalline (mc-Si), amorphous (a-Si), copper indium gallium diselenide (CIGS), and cadmium telluride (CdTe), with and without thermal exergy. Considering that the life span of greenhouse materials varies from ۵-۳۰ years for low cost, medium, and high-tech greenhouses, different solar cell materials are recommended for different life spans of GiSPVT. Therefore, this study recommends suitable solar cell materials for known greenhousedesigns:(a) The EPBT and (LCCE considering thermal exergy for c-Si/mc-Si range from approximately ۳.۵ to ۴.۵ years and ۱۳ to ۲۲%, respectively. Consequently, these values render crystalline silicon solar cells highly fitting for application in high-tech greenhouses with a comparable lifespan.(b) For the CIGS, the EPBT is ۱.۱۷ years with an associated LCCE (including thermal exergy) of ۱۶.۴۴%. This establishes CIGS as particularly well-suited for deployment in cost-effective greenhouse environments designs:(a)  EPBT and LCCE for c-Si/ mc-Si are about ۳.۵ to ۴.۵ years and ۱۳ to ۲۲%, respectively, with respect to thermal exergy. Hence, these two solar cell materials are most suitable for high-tech greenhouses that are similar to crystalline solar cell in terms of life cycle. (b)  EPBT and LCCE of CIGS are ۱.۱۷ years and ۱۶.۴۴%, respectively, with respect to thermal exergy. Hence, the solar cell material of CIGS is most suitable for low-cost greenhouses.

Keywords:

Solar cell materials , PV Module , Energy matrices , Solar energy