| Title | Influence of surrounding soil types on the energy efficiency of earth-air heat exchanger |
|---|---|
| Authors | Cuny, M; Lin, J; Siroux, M; Fond, C |
| Year | 2016 |
| Conference | European Geothermal Congress |
| Keywords | renewable energy, earth-air heat exchanger, geothermal platform, simulation |
| Abstract | As one of the direct uses of geothermal energy, earth-air heat exchanger (EAHE) systems are now in full development. However, the energy efficiency of these systems depends essentially on thermal proprieties of soil around the buried exchangers as well as the oscillation of the air temperature over ground. In this context, a study is conducted to quantify the impact of surrounding (especially the coating part) soil types on energy efficiency of heat exchangers. Firstly, the geothermal platform of IUT Robert Schuman University of Strasbourg in France with 3 horizontal ground-coupled heat exchangers is presented. Our study focuses on one of the experimental earth-air heat exchangers, where three types of soils are used around the heat exchanger: fine sand, a mixture of sand and bentonite, and a clay soil. At different vertical EAHE section, soil and flowing air temperatures are measured. Based on the registered data for the year of 2014, a 2D finite elements EAHE modelling is realised and validated for each section. A comparative study is then carried out with different coating soils. Finally, a suitable coating soil type is proposed for optimum energy efficiency of the EAHE system. |