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

Abstract

A multidisciplinary team comprising researchers at Cranfield University at Kitakyushu, a local architectural and engineering practice and the Development Office for KSRP examined how urban form could enhance the opportunities for more sustainable development. Options for energy provision particularly was considered at the scale of the overall site development and for the individual dwellings, as apartments, terraced and detached housing. A holistic approach was taken for the development of a 1-hectare site in order to assess the potentials and opportunities for energy systems and environmental solutions at this scale.Subsequently a team from Cranfield University at Kitakyushu and the Environmental Engineering Faculty at Kitakyushu University investigated options for cogeneration on this development site in the form of Combined Cooling Heat and Power (CCHP). The options ranged from a centralised system based within the apartment building that served all the dwellings on the site to individual 1 kW electric cogeneration systems that served individual dwellings. A computer software model was used to examine the energy efficiencies of these options from hourly through to annual timescales, based upon typical electricity, heating, cooling and hot water consumption profiles for Japanese dwellings. In Japan a hot bathtub is filled each evening throughout the year and is used by the whole family. This constitutes a base load for hot water consumption that could be served through thermal storage. At present high output capacity gas boilers are used to provide the hot water for this purpose. Consequently, the computer models considered modes and scales of thermal storage as one of the key parameters for the examination of the relative viability of the options considered.The analysis was carried out using hourly weather data provided by a Test Reference Year weather data file for the local area.