Affiliation: | a Residential Cogeneration Development Department, Osaka Gas Co., Ltd., Science Center Bldg., 3rd, 93 Chudoji Awata-cho, Shimogyo-ku, Kyoto 600-8815, Japan b Residential Cogeneration Development Department, Osaka Gas Co., Ltd., 3-4 Hokko Shiratsu 1-chome, Konohana-ku, Osaka 554-0041, Japan |