Exergy analysis of photovoltaic thermal integrated biogas system

In this communication, an analytical expression for slurry temperature as a function of design and climatic parameters of photovoltaic thermal (PVT) integrated biogas system has been derived. Also, exergy analysis of the given system has been carried for the month of January for Srinagar (Kashmir), India. The effects of mass flow rate ((m) over dot(f)), number of PVT collectors, length of heat exchanger (L), and heat capacity of slurry on slurry temperature (T-s) have been studied under forced mode of operation. For a given capacity of slurry a system comprising of PVT collectors in series combination has been studied for achieving optimum slurry temperature (T-s) of similar to 35 degrees C to ensure maximum biogas production. The results have been analysed for three cases namely: case (i) conventional flat plate collectors, case (ii) partially covered flat plate collectors and case (iii) fully covered photovoltaic module. It was concluded that the system consisting of partially covered flat plate collectors as discussed in case (ii) is highly sustainable and efficient for functioning in harsh cold climatic conditions that exists in Srinagar (Kashmir), India because it produces both thermal as well as electrical energy simultaneously. (C) 2015 AIP Publishing LLC.