2002 Volume 27 Issue 84 Pages 77-86
This paper constitutes Part 4 in the series of studies on hybrid utilization of renewable energy for a low energy house in which a ground source heat pump system is applied for heating and cooling as a main strategy. Firstly, energy, CO_2 and economical payback periods of natural energy utilization systems adopted for an experimental house were calculated. It was shown that their periods on energy and CO_2 emissions were both within 8 years. Secondly, it was clarified that the life cycle energy and the life cycle CO_2 reduction rate to a conventional house in Hokkaido reached over 50% by using operating results at the experimental house. As a result of numerical analyses on thermal insulation performance and equipment composition of a low energy house, the maximum values of the life cycle CO_2 reduction rate in Sapporo and Tokyo were 69% and 63%, respectively.
