Experimental study of a stand-alone earth to air heat exchanger for heating and cooling in arid regions
1Laboratory of Energy in Arid Areas (ENERGARID), University of Bechar, Bechar, Algeria
2Unit of Research on Material and Renewable Energies, Department of Physics, Faculty of Sciences, Abou Bekr Belkaid University, Tlemcen, Algeria
3Department of Technology, University Centre of Naama – Ahmed Salhi, Naama, Algeria
4Mechanical Engineering Department, Prince Sultan Endowment for Energy and Environment, Prince Mohammad Bin Fahd University, Al-Khobar, Saudi Arabia
J Ther Eng 2021; 7(5): 1206-1215 DOI: 10.18186/thermal.978023
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Abstract

Earth to air heat exchanger EAHE is a renewable technique based on a geothermal source. Arid regions are characterised by hard winter and summer weather conditions, which lead to a large thermal discomfort for the big part of the year. In this paper, we study by experiments the performance of stand-alone earth-to-air heat exchanger without external devices (fans, etc.), but only with the local climatic conditions of the region of Bechar (located in the Southwest of Algeria). The EAHE contains a PVC pipe with 66 meters of length and 110 mm of diameter, and it is buried at a depth of 1.5 m in an agriculture zone, where the annual undisturbed sub-soil at 1.5 m is 28°C. The stand-alone EAHE has the capacity to raise the air temperature by 10°C in the heating regime and reduce it by 11.9°C in the cooling regime. Furthermore, the relative humidity is raised by19% in the humidification regime and reduced by 27% in the dehumidification regime. The daily working regime was: 62.5% of heating (from 00h to 08h and from 18h to 23h) and 37.5% of cooling (from 09h to 17h) for the thermal regime, 62.5% of dehumidification (from 00h to 09h and from 18h to 23h) and 37.5% of humidification (from 10h to 17h) for the hygrometric regime. The stand-alone EAHE technique presents a great potential for the pre-heating, pre-cooling, and natural ventilation of dwellings and buildings in arid regions.