태양열발전용 소듐 히트파이프 흡수기의 실험결과

As one of important parts in concentrated solar power system, the solar receiver has been widely studied for various applications and performance improvement. Recently, the high-temperature solar receivers using alkali metal heat-pipes attract attention because of good heat transfer rate and large thermal inertia. Therefore two types of bent cylindrical sodium heat-pipe receivers, a bolted heat-pipe receiver and a brazed heat-pipe receiver, were developed including a heat exchanger to heat up water. They were tested with a dish concentrator made of 10 reflector facets. The purpose of this experiment is to compare two receivers via temperature distribution at heat-pipe and efficiency of receiver while the input power of each receiver changes by opening and closing reflector facets. Before the experiment, the flux mapping method was used to measure the input power and the heat flux distribution at the receiver aperture. The maximum input power of the dish concentrator turned out to be 4.73 kW at the level of 1 kW/m2 direct normal insolation. Total heat transfer rate to water was calculated with the measured temperature difference at inlet and outlet of water. After all, the receiver efficiency was calculated by dividing the total heat transfer rate with the measured input power.