Life cycle CO{sub}2 emission of a solar/midnight electricity/gas hot-water supply system

摘要

Reduction effect of life cycle CO{sub}2 emission of a solar/midnight electricity/gas hot-water supply system are investigated. Assuming that the system is installed in a welfare facility in Shizuoka, CO{sub}2 emission during system operation is calculated by annual simulation using weather data. The operation methods with and without insolation forecast are considered for a solar/midnight electricity system. The results show that (1) 70% of CO{sub}2 emission is reduced when combining a gas system with solar collector, (2) it is important for a midnight electricity system to combine it with solar collector and to operate the system using insolation forecast, (3) a solar/heat pump system minimizes the CO{sub}2 emission, but maximizes the annual cost.