Abstract
In order to evaluate effectiveness of a combined system of solar heat collecctor (SHC) and heat pump water heater (HPWH), optimum operation scheduling moldel of domestic electric appliances using the mixed integer linear programming was enhanced. Applying this model with one house data in Tokyo, it was found that the combined system of the SHC and the HPWH has the enough energy-saving and CO2 emission reduction potential under the existing electricity late and the operation method of the HPWH. Furthermore, the calculation results under the future system show that the combined system of the SHC and the HPWH has also the reduction effect of reverse power flow from residential photovoltaic system.