A MULTI-FUNCTION SOLAR HEAT PUMP SYSTEM
An innovative multi-function solar heat pump system is investigated in this study. The most important feature of this system is that it can serve space heating/cooling, water heating and drying simultaneously or independently. A system was designed and fabricated and a series of experiments were conducted to evaluate the performance under the meteorological condition of Singapore. Comparison of the multi-function system for different running modes and speeds of the compressor was carried out. The presence of evaporator-collector enabled the system to work round the clock, even in the absence of sunlight. Refrigerant R134a was selected as the working fluid due to its favourable thermodynamic properties. Experimental results show coefficient of performance (COP) of 4.58. Experimental results obtained under part load show that the air-conditioning greatly enhanced the heating effect. The efficiency of the unglazed evaporator-collector, which was found to be close to 1 with a maximum of 1.7, is much higher than the conventional collector. Results indicate that this multifunction system can meet domestic and industrial requirements and save considerable amount of energy when compared with the conventional air-conditioner, water heater and dryer. The system is considered environment friendly and show good potential for application in tropical areas, where solar energy is abundantly available.