การวิเคราะห์สมรรถนะของโมคูลโฟโตวอลเทอิก/ความ ร้อนร่วมกับปั๊มความร้อนเพื่อการผลิตความร้อนและไฟฟ้า

Abstract

Photovoltaic/Thermal module (PV/T) has been developed to convert solar energy to electricity and make use of thermal heat dissipation into hot water. The utilization of hot water enables system’s efficiency. The temperature and amount of heated water depends on both solar insolation and the number of modules used. This research work aims to investigate the potential of producing hot water by the use of solar PV/T incorporating with 3,000-W vapor-compression heat pump. The heat pump is used to extract the heat loss from PV/T modules stored into an intermediate water tank. Designated to be connected in parallel, each PV/T module is rated at 200 Wp with 1.326 m2 aperture area. Heat pump is tested for its performance in response to the temperature of evaporator and condenser sides which is barred by the temperature of the water tanks; set at 25 ˚C and 60 ˚C, respectively. Based on the city of Chiang Mai’s insolation and temperature, mathematical modeling of the system is formulated for the utilization of 350, 500, and 700 liters of hot water on heat pump’s condenser side. It is conditioned such that the hot water tank will reach 60 ˚C at the end of the day by the heating from PV/T and auxiliary heater powered by available national grid electricity and all hot water is consumed during the nighttime. Electricity produced by PV/T is only used within the system. The performance of the system is determined in terms of generating heat-rate-and-power ratio (H/P) and also the utilization factor. Model analysis is studied for 350, 500, and 700 liter of hot water on condenser side. It is shown that the utilization factor increases in response to the number of PV/T module used. Utilization factor ranges between 1.84-3.90. When compared with the use of heater to warm 350, 500, and 700 liters, the system can save the electrical energy more than 90, 90, and 75%, respectively. This responses similarly in terms of H/P. The H/P ranges 2.05-3.33 for the system with 350 liters of hot water and 2.17-3.43 for the system with 500 liters but drops to 2.01-2.96 for the 700-liter system. This is emphasized through the economic analysis where the payback period of the systems is determined. The lowest payback period is reported for 350, 500, and 700 liter as 5.22, 3.61, and 4.55 years but this can be achieved only when the number of PV/T module used is 8, 8, and 10, respectively, and the intermediate water tank is at 300, 300, and 50 liter, respectively. Therefore, the heat pump used, the system is optimized at 500 liter of hot water demand with the used of 300-liter intermediate water tank and 8 PV/T modules as the payback period is the lowest among all cases at 3.61 years.