Assessment of an integrated active solar and air-source heat pump water heating system operated within a passive house in a cold climate zone

• An integration solar water heating system was designed and constructed in a full-scale test house.
• Thermal performance of the system in coldest period was tested and analyzed.
• The reasonable running procedure suggestions were proposed.

In the pursuit of energy savings and emission reductions, solar energy heating systems have been promoted in China. However, there still exist many barriers to the operation of solar heating systems, in combination with other systems, under realistic conditions. In order to investigate this further, an integrated space heating system including passive sunspace, active solar water heating, and air-source heat pump (ASHP) was built. The detailed running performance of each subsystem was comparatively analyzed in a full-scale test house in a cold climate zone. This integrated system showed many encouraging results in terms of the maintenance of a stable and comfortable indoor thermal environment during the winter season. The study building consumed electricity as convectional energy, which only accounted for about one-third of the total energy supplied for heating. However, our study also found some shortcomings in the system design. Feasible suggestions regarding the running procedures aimed at a more optimal and effective design were proposed. The systems proposed in this study could be used as a promising future technology for energy savings and emission reductions in rural buildings. The study could also help achieve targets for energy savings and renewable energy utilization in China and other countries.