Solar hybrid heating systems for greenhouses

Theoretical prediction of the total heat requirements of a greenhouse using several solar hybrid systems under various representative Jordanian ambient conditions have been carried out. Either an air-source heat pump, a water-source heat pump, a boiler, and electric-resistance element system or a combination of these was considered as the heat source. The operation-cost analysis which was carried out indicated that for the given ambient conditions the hybrid solar heat-pump system was in general the most economic.