Exergy assessment of a semi-transparent building integrated photovoltaic facade for mild weather conditions of Srinagar

Abstract

Effective utilization of solar energy reduces the dependence on fossil fuel usage along with achieving the objective of carbon neutrality. The current work aims to numerically assess the performance of a facade based semi-transparent BIPVT system while considering four different weather conditions in a month for the climate of Srinagar, India. In the proposed configuration, the BiSPVT facade serves the dual purpose of generating electrical power gain and providing pre-heated air for space heating. PV module surface was cooled by flowing air through the air channel. Movement of air through the cavity takes away the heat from the PV module back surface reducing the temperature of the solar cells resulting in enhanced module efficiency. System performance has been evaluated in terms of obtained energy and exergy using a 1-D numerical model developed in MATLAB. The Exergy analysis presented shows an informative means of estimating system functioning based on qualitative aspect of useful energy gained. For a mild cold weather condition of Srinagar, with minimum ambient temperature dropping to 1.2 °C, useful daily exergy gain of 0.0545 kWh/m2 has been achieved signifying the increase of space heating during winters of cold climatic regions. Maximum temperature difference between room and ambient was obtained as 9.76 °C using the BiSPVT façade. Results shows that the proposed BiSPVT system was able to produce monthly electrical and thermal exergy gain of 12.56 kWh/m2 and 16.81 kWh/m2 respectively. Exergy efficiency of the system was determined in the range of 18.2%-19%. Further, environmental assessment of the PV façade system based on CO2 emission gave an estimated amount of 0.387-ton CO2 emission reduction for the month of November leading to environmental cost reduction of 5.615$/month.