Design and optimization study of a densely packed ultrahigh concentration photovoltaic thermal array for desalination usability

The cogenerated energy from the densely packed ultrahigh concentration photovoltaic thermal systems (UHCPV/T) can not only promote higher exergetic efficiency but also enable the usability of the collected thermal energy for potential desalination purposes. In the present study, three finned heat sink designs of UHCPV/T have been proposed toward maximum collected thermal power and minimum required pumping power. A conjugate heat transfer model has been developed and validated to simulate the different designs under various operating conditions. The cooling setups are based on copper millimeter-scale finned heat sinks immersed in fully developed laminar flow in a rectangular microchannel. It was found that the configuration from the more efficient heat sink design to the poorest thermal one is the rectangular fins (RFs), elliptical fins (EFs), diamond pin-fins (DPFs), and then traditional round pin-fins (TRPFs) heat sink. The RF heat sink has demonstrated the best thermal performance with a maximum multi-junction solar cell (MJSC) temperature of 81.4°C and water temperature increase of 14.21°C under ×1200 and water inlet velocity of 0.02 m/s. Despite the RF heat sink has recorded the highest values of pressure drop and required pumping power equal to 78.74 Pa and 570.7 mW, respectively, it was selected as the optimal heat sink design, ensuring the highest net electrical output power and thermal collected power.