Solar assisted heat pump in dual mode: direct and indirect space. Heating by the air collectors. Simulation results and evaluation with measurement results

The heating system of the bioclimatic building of CRES comprises the entire heating plant including a solar assistedheat pump, the Solar Air Collectors (SAC) as well as the heat distribution system (comprising a fan coil unit network). The solar air collector configuration as well as the fraction of the building-heating load coveredby the heating plant are assessed in the article, for two modes of operation, the direct mode (hot air from the collectors is supplied directly to the heated space) and the indirect mode (warm air from the SAC or its mixture with ambient air is not supplied directly to the heated space but into the evaporator of the heat pump).The technique of the indirect mode of heating aims at maximizing the efficiency of the SAC, at saving electricalpower consumed by the compressor of the heat pump and, therefore, at optimising the coefficient of performance (COP) of the heat pump due to the increasedintake of thermal energy from the environment by means of the SAC.