Huang B.J.Lee J.P.Chyng J.P.2019-06-262019-06-2620050038092Xhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-13844264270&doi=10.1016%2fj.solener.2004.08.009&partnerID=40&md5=16b7668f51b1e6a7c610375ea755e88fhttps://scholars.lib.ntu.edu.tw/handle/123456789/411434A heat-pipe enhanced solar-assisted heat pump water heater (HPSAHP) is studied. HPSAHP is a heat pump with dual heat sources that combines the performance of conventional heat pump and solar heat pipe collector. HPSAHP operates in heat-pump mode when solar radiation is low and in heat-pipe mode without electricity consumption when solar radiation is high. HPSAHP can thus achieve high energy efficiency. A prototype was designed and built in the present study. An outdoor test for a HPSAHP in the present study has shown that COP of the hybrid-mode operation can reach 3.32, an increase of 28.7% as compared to the heat-pump mode COP (2.58). © 2004 Elsevier Ltd. All rights reserved.Heat pump; Solar heat pump; Solar thermal; Solar water heater[SDGs]SDG7Electricity; Energy efficiency; Heat pipes; Heat pump systems; Solar collectors; Solar radiation; Electricity consumption; Heat pump modes; Heat pump water heaters (HPSAHP); Solar heat pipe collectors; Solar water heaters; heat pipe; heat pump; heating; solar powerjournal article10.1016/j.solener.2004.08.0092-s2.0-13844264270