Design and analysis of a multigeneration system with concentrating photovoltaic thermal (CPV/T) and hydrogen storage

Concentrated photovoltaics (CPV) is an auspicious technology to overcome the high cost problem of highly efficient multi-junction solar cells. However, due to huge concentration of light energy, high heat flux dissipation from a confined space is a challenge. The proposed system here is first of its type to apply and thermodynamically analyze the Nucleate Pool Boiling Heat Transfer (NBHT) for thermal management of CPV. In order to increase overall efficiency of CPV system, a multigeneration system using concentrated photovoltaic thermal (CPV/T) and hydrogen storage is designed and thermodynamically analyzed to fulfill electricity, hot and cold water, heating ventilation and cooling (HVAC) requirement of a residential community with continuous operation. A part of the generated electricity from CPV is used to power the electrolyzer to produce hydrogen and oxygen. The produced gases are stored, and reused by proton exchange membrane fuel cell (PEMFC) to fulfill the system's electrical energy requirement during night time and unfavourable energy conditions in day time. The resultant thermal energy from CPV/T is used for the heating, hot water and cooling requirement of the buildings by employing lithium bromide absorption chiller (AbC). A humidity harvesting system is connected, at the outlet of the absorption chiller, to convert humid air into water and ventilation air requirement of the building. The designed system performs at 67.52% overall energy efficiency, 34.89% of overall exergy efficiency and up to 1862 times concentration ratio at designed steady-state conditions. The results show that with an increase in boiling temperature of NBHT from 353 K to 373 K, the maximum concentration ratio ability increases significantly from 1392 to 2400 times due to increase in critical heat flux, while the electrical efficiency of the CPV system decreases from 28.65% to 27.09% because of increase in cell temperature. To verify the performance of the designed system for different locations, operating conditions and capacities, the effects of Direct Normal Irradiance (I_DNI), ambient temperature, relative humidity ratio and the installed capacity are also analyzed by the parametric studies.