Research on the operation strategies of the solar assisted heat pump with triangular solar air collector

Abstract

The solar-assisted heat pump (SAHP) is considered to be one of the efficient and promising clean heating technologies, while the research on its operation strategy is insufficient. In this study, a novel triangular solar air collector assisted air source heat pump (TSAHP) for rural residence heating is presented. Three working modes of the TSAHP including preheating, series and parallel modes were investigated, and corresponding mathematical models were established and verified. The effects of solar irradiance, outdoor temperature, indoor temperature, south wall covered area of the TSAC and the heating load on the performances of the three working modes were analyzed. The distribution diagram of the optimal working mode was designed, and the equations that define the boundaries between operating modes were fitted. Finally, the performances of the TSAHP under typical meteorological parameters were compared and analyzed based on the modified boundary equations. Results indicate that the TSAHP can sufficiently utilize solar energy. With the increase of solar irradiance, the optimal working mode is shifted from the preheating to series and parallel. Compared with the traditional air source heat pump system, the COP of the TSAHP under the optimal working modes could be increased by 64.4%.