Annual performance comparison between solar water heating system and solar photovoltaic/thermal system-A case study in Shanghai city

Abstract

Based on the typical meteorological year data of Shanghai city, annual performances of solar water heating (SWH) system and photovoltaic/thermal (PV/T) system are comparatively analyzed under three different cases. The results show that when only solar energy is used, the effective day number of SWH system is more than PV/T system under the same case every month; for the PV/T system, heat loss at the nighttime dissipates most of the absorbed solar energy under the continuous heating mode considering the nighttime heat loss case; initial water temperature determines system electric efficiency. On the whole, PV/T system offers competitive performance only under the auxiliary heating mode, no matter from the points of primary efficiency and static payback period.