This paper describes the effectiveness of a residential gas engine combined heat and power (GE-CHP) system for cold regions for energy conservation. Residential CHP system has attracted attention for its high energy saving and environmental performance. In Hokkaido as a cold region, high energy demand exists, which causes a large amount of CO₂ emissions and energy consumption compared to national average. Under such circumstances, we conducted demonstration tests of 11 residential GE-CHP systems in Sapporo. The exhaust heat of the GE-CHP systems of the demonstration tests were used for ventilation warming, while exhaust heat of the GE-CHP systems were used for hot-water heating in the usual case. According to the data of demonstration tests, the amount of reduction in primary energy was an average of 4.8 MWh/year compared with the conventional type (commercial power + non-condensing boiler), which includes an average of 0.38 MWh/year reduction by using the ventilation warming. Compared to the results of previous demonstration tests which used same GE-CHP without ventilation warming, the amount of reduction in primary energy showed significant differences.

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This study aims to verify the effectiveness of optimum utilization of residential combined heat and power (CHP) systems such Gas Engine (GE), Polymer Electrolyte Fuel Cell (PEFC), and Solid Oxide Fuel Cell (SOFC) for energy conservation for cold regions. First, we carried out a questionnaire survey. Second, we predicted electrical demand, domestic hot water demand, and space heating demand from the questionnaire. The results show the margin of error of predicted electrical demand, domestic hot water demand, and space heating demand to the measured values were 14.3%, 21.1%, and 30.6%, respectively. Finally, we developed the simple simulation in order to calculate the energy conservation of CHP systems. The results shows the margin of error of the amount of reduction in primary energy compared with the conventional type (commercial power + non-condensing boiler) of GE, PEFC, and SOFC to values obtained by an optimum simulation using measured demands were 15.8%, 17.6%, and 18.1%, respectively.

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This paper describes field measurements conducted in several households with different heat demands for performance evaluation of residential combined heat and power (CHP) systems, which are increasingly becoming efficient domestic hot water supply systems using a storage tank, and the hybrid utilization effect with photovoltaics (PV). The annual dependence rate (33%) of electric power of a gas engine (GE)-CHP stood comparison with an average value (34%) of 205 polymer electrolyte fuel cell (PEFC)-CHPs by the New Energy and Industrial Technology Development Organization (NEDO) and the New Energy Foundation (NEF). The annual dependence rate of electric power of SOLAR-CHP integrated PV and solar collectors (SC) was 25%. The tendency was showed that a reduction effect of GE/PEFC-CHP improved quantitatively as the amount of exhaust heat use was large. The amount of annual PV power generation turned out almost a value of the previous large scale survey by NEF. As a result of the hybrid utilization of CHP and PV, the amount of the reverse power rose 30-123% from a case only PV. The peak electricity reduction effect in summer was improved conspicuously in comparison with a case only CHP. In addition, the growth rate of the amount of the primary energy reduction when the reverse power included was 82-236%. In the hybrid system of CHP and PV, the payback period of PV was 10.3-21.5 years. The economical introduction effect was confirmed in comparison with the use of PV only (11.7-25.7 years).

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