Experimental Study of a Self-pumping Boiling Collector Solar Hot Water System

An experimental study of a pilot scale passive solar hot ~ater heating system utilizing a boiling collector is presented. The self-pumping system alternates between two modes of operation. During the run . cycle, vapor pressure drives the evaporated refr1gerant downward from the collector to the condenser. Once a preset quantity of refrigerant is condensed, vapor pressure is again used to force the return of the cond~nsate to t~e collector during the pump cycle .. The pilot .system is optionally configured ~o operate with a mechanical pump . Experimental results i~cl~de measurements of temperatures and pressures withi~ the system a~ well as thermal input and output energ ies. The loss in thermal efficiency due to the use of vapor p~essure to return liquid refrigerant to the collec~or is ~ssessed by comparing self-pumping and mechanical-pumping operation. Performance of the selfpumping system is strongly influenced by transient ~herma~ lo.sse.s.. Refinement of the system design, including i.nd1vidual components, is required to reduce losses and 1mprove performance.