Investigation and modelling of the centralized solar domestic hot water system in residential buildings

The solar domestic hot water (DHW) system is applied as a building energy saving technique. The centralized system, which is considered to provide both energy efficiency by exploiting solar energy and high-level services to the customers as the occupants could have access to the hot water at any time during the day, is widely used among the various forms of solar DHW systems. The real performance of a centralized solar DHW system is measured, based on which a model describing the solar energy collection, water supply, and terminal water use is built. The simulation reveals that the actual energy performance of the centralized DHW system is closely related with the occupant behaviour, i.e., the water use patterns of the occupants residing in a building. This study concluded that whether the DHW system is energy efficient or not could not be evaluated without considering the water use patterns of the occupants.