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.

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