A new approach to modelling of a horizontal geo-heat exchanger with an internal source term

• Published in: Applied energy 2016-02, Vol.164, p.963-971
• Main Authors: Sofyan, Sarwo Edhy, Hu, Eric, Kotousov, Andrei
• Format: Article
• Language: English
• Subjects: Geo-heat exchanger; Internal source term; Thermal modelling
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2015.07.034

•A new GHE model with an internal source term approach is presented.•The theoretical results are in a good agreement with the experimental data.•The effects of the technical parameters on the GHE’s performance are investigated. This paper presents a new approach to considering the effect of seasonal changes in soil temperature on the performance of a horizontal geo heat exchanger. It is different from extant models which consider the seasonal changes in soil temperature by applying a real energy balance on the ground surface. In the new model, the seasonal changes in soil temperature, which are affected by the thermal interaction between the ground and the atmosphere, are expressed as an internal source term. The value of the internal source term depends on the soil density, soil specific heat, soil temperature difference during summer and winter, and time period. The simulation results show that the new approach, which takes into account the effect of periodic soil temperature fluctuations on the performance of the horizontal geo heat exchanger, is valid. The validated model is then used to conduct a sensitivity analysis to investigate the effects of the pipe length, fluid flow rate, inlet fluid temperature, and burial depth on the thermal performance of the horizontal geo heat exchanger.