Examination of the Viability of Co-generation for a Small-scale Housing Development in Kitakyushu, Japan

摘要

Co-generation, also known as CHP (Combined heat and power), is an efficient approach to generating electricity and thermal energy from a single fuel source. By recycling this waste heat, it can achieve the primary energy efficiencies of 40% to 70%. And higher efficiencies reduce air emissions of carbon dioxide and sulphur dioxide. At the same time, co-generation can provide high-quality and reliable electricity supply. In Japan, during the last 20 years, co-generation has been developed rapidly. The number of co-generation systems increased from 67 in 1986 to 4515 in 2003, and the total generation capacity has increased from 200Kw in 1986 to 6,504MW as of March 2003. According to a survey, co-generation systems have mainly been installed in the industrial and commercial sectors in Japan and power output of co-generation plant generally is more than 1Mw. However, the energy consumption for dwellings in Japan accounts for 26.4% of total primary energy. Based on mis, small-scale CHP plants should have a potential market in Japan. This paper examines the viability of small-scale co-generation by analysis of a case study in Kitakyushu, Japan. A computer software model was used to examine the energy efficiencies of a number of options from hourly through to annual timescales, based upon typical electricity, heating, cooling and hot water consumption profiles for Japanese dwellings. In order to obtain a reasonable the ratio of heat to electricity demand, a different match was selected for heat load and electricity load in the apartment, terrace house and detached house categories. Four options combining gas-boiler and gas-turbine are evaluated regarding energy efficiency, environmental load and economic efficiency.