Application of heat pump assisted solar evacuated tube water heater operated within passive solar house in severe cold region

Replace coal with solar energy to low-cost heating in severe cold regions can improve indoor air quality, but indoor thermal comfort is not fully guaranteed. Therefore, a dual-source heat pump (DSHP) assisted solar evacuated tube water heater heating system was used in a house with sunspace to meet the heating stable and cleaning. TRNSYS model verified by experiment was used to research performance and economy of system. Results found the higher ambient temperature and solar radiation, the more heat from sunspace, solar assisted heat pump (SAHP) and solar water heater, conversely, the longer heating time of air-source heat pump (ASHP). During heating season, solar fraction of heating was 51.6 %, solar heat collection efficiency was 46.0 %, EER was 3.35, COP were 2.81 (ASHP) and 3.65 (SAHP). Heating time proportion of ASHP, SAHP and solar water heating were 15.0 %, 40.3 %, 44.7 %, ASHP heating was accounting for 22 % and 50 % in November and January. The system, sunspace supplied 16707.1, 2307.6 kW h of heat for room, solar effective heat collection was 10107.0 kW h, power consumption was 5164.7 kW h, CO2 emission reduction was 14232.4 kg. The dynamic payback period of system was 6.78 years, as will be shortened with support of clean energy heating policy.