Survey on the actual operation and the performance of central heating system for highly insulated and airtight houses in hokkaido

Abstract

In order to search trends in further energy saving in highly insulated and airtight houses in Hokkaido, Japan, an actual-condition investigation on a central-heating system fitted in five such houses, each with different methods of construction, was performed. The results were obtained as follows.: l)The equivalent leakage area value of a steel frame construction was 3.2cm 2/m2 that was less than a two-by-four construction(0. 33cm2/m2) and a conventional wood construction(l.l-1. 7cm2/m2) .It is important to be improved air-tightness of steel frame construction houses by various construction methods. 2) Heat loss coefficient estimated from these experimental results was 0.94 -1.59W/(m 2,K). To reduce energy consumption for heating,it will become more important to improve thermal-insulation properties and air tightness.3) The heating-system efficiency obtained from these experimental results was in the range of 72 to 93%. Although the ratio of actual boiler capacity to demanded heat-source capacity extrapolated from actual measurements ranges from two to three times,the effect on system efficiency was less than 10%.However it is necessary to include this 10% in the task of planning a heating system.