Renewable Energy, Vol.159, 538-546, 2020
Experimental evaluation of ground heat exchanger in UAE
In this paper, an experimental investigation is conducted to examine the performance of a ground heat exchanger (GHE) in Sharjah city in the United Arab Emirates (UAE). The paper reports and discusses the results of two shallow geothermal experimental studies. The first study evaluates ground temperature distribution for two boreholes, with depth of 10 m each, over a period of seven months. The ground temperature distribution results have showed that the mean ground temperature is around 32 degrees C which is 5 degrees higher than the year-average ambient temperature. The second study examines the performance of a GHE under Sharjah city conditions. The GHE is fabricated using a 300 m long plastic pipe with 0.03 m diameter pipe, which has been horizontally buried at 2.5 m below ground surface. The results show that the ground temperature increases due to GHE and that the ground needs around 9 h to dissipate its thermal energy. A mass flow rate of 0.15 kg/s has provided higher heat exchange and higher GHE effectiveness when compared to lower flow rate of 0.0375 kg/s. The GHE effectiveness decreases over time and the rate of drop in effectiveness becomes more pronounced as mass flow rate increases. (c) 2020 Elsevier Ltd. All rights reserved.
Keywords:Ground heat exchanger (GHE);Ground source heat pump (GSHP);Shallow geothermal;Vertical ground temperature distribution;Closed loop horizontal systems