A hybrid system coupling spiral type solar photovoltaic thermal collector and electrocatalytic hydrogen production cell: Experimental investigation and numerical modeling

The sustainable cogeneration of hydrogen and electricity is one of the promising strategies to boost the world's energy demand. This work introduces a detailed numerical modeling and experimental study for a small-scale tri-production of heat, electricity, and hydrogen via an electrocatalytic hydrogen production cell (EHPC) powered by a solar photovoltaic thermal collector (SPVTC). A novel type of spiral fluid SPVTC integrated with small-scale Hoffman's EHPC is designed and tested. The effect of type and flow rate of cooling fluid on the performance parameters of the hybrid SPVTC-EHPC; including PV electric power, surface cell temperature, cooling fluid exit temperature, electrical and thermal efficiency, and produced hydrogen yield is studied. The experimentations are carried out for the hybrid SPVTC-EHPC operating with two various cooling fluids, namely, water and air at various mass flow rates (20 and 40 L/h), and their results are compared with a standalone PV module without cooling. Moreover, CFD modeling of the water SPVTC, air SPVTC, and PV module designs is also conducted at different operating conditions. ANSYS software is applied to attain maximal efficiency from the collector by choosing the optimal spiral flow structure and determining the PV panel surface and coolant temperatures of the three proposed systems. The CFD simulation verification ensured a good fit between the computational and experimental results. The findings show that the reduction in the daily average PV surface temperature is obtained as 16.60% (54.46 °C) and 8.50% (59.75 °C) for the SPVTC-EHPC, compared to reference PV-EHPC system, when water and air are utilized as a coolant at flowrate of 40 L/h, respectively. Moreover, the daily hydrogen productivity is found as 4.41 kg_H2/d for water-cooled SPVTC-EHPC (40 L/h), 4.03 kg_H2/d for water SPVTC-EHPC (20 L/h), 3.60 kg_H2/d for air-cooled SPVTC-EHPC (40 L/h), 3.24 kg_H2/d for air SPVTC-EHPC (20 L/h), and 3.07 kg_H2/d for the conventional PV module EHPC, respectively. This study offers an effective means to experimental and numerical aspects of both water and air-cooled SPVTC for the simultaneous production of electricity and hydrogen.