Assessing the potential of using geothermal energy in buildings: Parametric analysis

Abstract

For the development of more energy-efficient buildings, pursuing comprehensive sustainable solutions can help decrease greenhouse gas emissions, and using natural resources sustainably and at low cost are challenging objectives for the achievement of the United Nations (UN) sustainable development goals. In this context, the main objective of this research is the evaluation of the energy-efficiency improvement of shallow geothermal systems, based on one case study building located at Aveiro University. The present research undertakes the improvement of several parameters with influence on the shallow geothermal systems efficiency, using as a demonstrator a university building in Aveiro University, the CCCI department building. The performed work was developed in three phases: (i) the acquisition of vertical temperature profiles in 15 exploration boreholes, (ii) the simulation of the buildings’ energy needs using EnergyPlus® software, and (iii) the evaluation of the energy demand of the geothermal system using HYGCHP® software. A sensitivity analysis was carried out with HYGCHP® by changing several parameters (average ground temperature, soil thermal conductivity, pipe radius, and total installation length) to assess the reduction potential of the annual energy consumption. Combining different parameters in the design phase allows a considerable reduction in the annual energy consumption. Two parameters are highlighted with a higher influence: the soil thermal conductivity and the average soil temperature (measured in the boreholes). A synthesis of the simulations carried out will lead to concrete recommendations and guidelines for future planning actions regarding geothermal systems installation to ensure sustainable use conditions, comfort, and health in the campus environment.