Gas heat pump for greenhouse heating in a stand-alone hydrogen plant: a mathematical study.

Nowadays, diesel, LPG and natural gas are the main energy sources used for greenhouses heating. Alternative solutions are represented by the integration of renewable energy plants in agriculture. The aim of this research was to analyze the energy performance of a photovoltaic, hydrogen and ground source gas heat pump (GSGHP) integrated stand-alone system during the winter season. The results showed that the system had a total energy efficiency to 12%. The performance of the system was low because the efficiency of the photovoltaic panels was low. In fact, starting from the energy available from the PV, the system has an efficiency of 96% if the COP of the heat pump is equal to 4. Finally, the heating system increased the greenhouse air temperature about 8°C respect to the external air temperatures.