DRAIN DOWN-TYPE CLOSED LOOP SOLAR ENERGY SYSTEM AND CONTROLLING METHOD THEREOF

摘要

PURPOSE: A drain down type closed solar system and a control method thereof are provided to prevent the burst of pipes caused by the freezing of the residual heat medium in the pipes. CONSTITUTION: A drain down type closed solar system comprises a solar heat collector(100), a heat storage tank(200), a thermal medium reservoir(300), a heat exchanger(400), a thermal medium circulating pump(P1), and a convection circulating pump(P2). The heat storage tank stores solar energy absorbed by the solar heat collector. The heat exchanger heat-exchanges a thermal medium of the solar heat collector with cold water of the heat storage tank. The thermal medium circulating pump circulates the heat-exchanged thermal medium in the solar heat collector. The convection circulating pump circulates the cold water of the heat storage tank in the heat exchanger. A drain down pipe(510) for collecting the thermal medium is installed between a thermal medium circulating pipe and the thermal medium reservoir.