Economic Analysis of Semi-Open Loop Ground Source Heat Pump Systems in Different Parts of Japan

Abstract

Ground Source Heat Pump (GSHP) systems have received enormous attention of energy decision makers for residential heating and cooling applications. Although, the obstacles such as high drilling cost especially in countries like Japan acts as barriers to the development of these systems. Therefore, the optimum design of a GSHP system with the possible lowest Ground Heat Exchanger (GHE) length plays the vital and important role in the early stage of these systems utilization. The shallower length of the GHEs, which is influenced by regions geological condition and also varies based on different heating and cooling loads can make these systems much more competitive comparing to the conventional systems. This study compares the well length of a system at two different parts of the country with totally different geological and weather conditions. The main goal of this paper is to investigate the effect of heating and cooling loads distribution and to carry out the economic analysis for this regions. In this research, a new type of GSHP system namely “Semi-open loop GSHP”, which is developed by the authors in their previous studies is simulated for Tokyo and Akita Cities in central and northern Japan, respectively. This system is installed in Akita University campus and its model in FEFLOW software is validated based on conducted thermal response tests (TRTs). Afterwards, the economic study was done for a specific heating and cooling load and based on Akita’s weather. This process was repeated similarly for Tokyo City importing the new time series of heating and cooling load as well as changing the average ground temperature (as one of boundary conditions) according to Tokyo’s recorded data.