Abstract
Recently, hot water supply systems using heat pump and cogeneration have been developed. Heat pump water heater is a
device which can supply hot water in making use of heat of atmosphere, and its COP is more than 4.0 in normal operation.
Heat pump water heaters have been introduced in many household. This study evaluates effects of reducing a tank capacity
and daily storage volume of hot water for one and decreasing heat loss in tank using actual monitored daily-bases demand
data of hot water by sharing with several households. And the authors assume a piping model which connects among several
households, calculates heat loss in pipe as demerit, and comprehensively analyzes heat loss in the hot water supply system.
