Experimental study on heat storage integrated flat plate solar collector for combined water and air heating in buildings

Combined water and air heating flat plate solar collectors can reduce water and space heating-associated energy costs at minimal installation. This study uses the serpentine copper tubes for water to have a more surface area and flow duration. Baffles are provided to increase air flow residence duration. In addition, multifunctional heat storage tubes are fixed on the absorber. The results reveal that the energetic and energetic performances of the collector are significantly affected by the solar radiation and mass flow rates of water and air. The heat storage integrated collector's peak energy and exergy efficiencies are 88.8 % and 3.5 %, respectively, higher than the collector without heat storage at the water flow rate of 0.025 kg/s and air mass flow rate of 0.0132 kg/s. The overall heat loss coefficient of heat storage integrated collector is 4.2 % lower at a higher flow rate than without heat storage. The heat storage tubes reduce heat loss, increase the absorber area, and compensate for the fluc-tuation of available solar energy. The presented hybrid solar collector has more economical and environmental benefits than the conventional collector with shorter payback periods.