The hot water test mode "modified m1"reflecting daily fluctuation, short-time usage and experimental analysis for the energy performance of the gas instantaneous boiler

Hot water occupies much of total residential energy consumption, and development of the energy efficient hot water system is critical. In this paper, for the impartial and realistic evaluation of the many types of hot water boiler, "Modified M1" mode was decided to reproduce the daily fluctuation and short time usage in the real houses. The experiment of the gas instantaneous boiler including the condensing one, was carried out and confirmed that the short time usage drops energy efficiency.