Energy efficiency analysis of a hydrogen and geothermal stand-alone system for greenhouses heating

This study investigates the performance characteristics of a hydrogen and geothermal stand-alone system for greenhouses heating. The systems consist of photovoltaic panels connected to an electrolyzer that, during the daylight hours, produce hydrogen and then it is stored in a pressure tank. However at night, thank to a fuel-cell, the hydrogen was converted to electric energy in order to feed a ground source geothermal heat pump for greenhouse heating. The following conversion energy efficiencies factor of each system were measured: photovoltaic panels, 13%, electrolyzer, 48%, fuel-cell, 41% and finally, the coefficient of performance of geothermal heat pump of 5, and then the overall system efficiency, starting from the amount of solar energy available during the daylight hours, was of 12.8%.