Regional difference of energy consumption for hot water supply system

This paper proposes useful techniques of regression analysis to estimate regional water temperatures for the optimum design of the hot water supply system. First yearly trends of changing air temperatures and water temperatures are surveyed about Sapporo, Sendai, Tokyo, Nagoya, Osaka and Kochi, which are typical cities with enough data to analysis from 1991 to 1994. Second three types of the explanatory variable of the regression model are examined: (a) the air temperature on that day, (b) the air temperature 1 or 2 days before and (c) the mean air temperature in a few days of the pasts. It is concluded that the regression model of (c) decreases standard errors of estimates. Finally coefficient of energy consumption for hot water supply, CEC/HW, are calculated from estimated regional water temperature.