Potential of district-scale geothermal energy in urban cities

Ground source heat pumps (GSHPs) is a shallow geothermal system of pumping heat from or to the ground to supply low carbon heating or cooling to buildings. The underground becomes a heart storage and combination of heating and cooling can be beneficial to system efficiency improvement and temperature balance underground. In this study, a GIS based simulation tool was developed to quantify how many GSHPs could be installed at a district or a city scale without losing control of ground thermal capacity, and to identify its contribution to both heating and cooling demands of buildings. The City of Westminster, London was selected as a case study. Results show that many buildings (more than 50%) can install enough boreholes to support their own heating and cooling demands. For high-rise buildings and the high people density infrastructures, the limited space for geothermal energy extraction is a concern for geothermal applications. As domestic buildings have more space to install boreholes and thus to obtain more energy from underground, residential houses can share their surplus geothermal energy with commercial buildings and urban infrastructure at city scale. Parametric analysis was carried out to investigate the influence of district size for sharing a GSHP network at city scale