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Heating capacity of an earth to air heat exchanger EAHE equipped with an exterior fan in the arid region like the Southwest of Algeria is investigated experimentally. In-situ measurement of annual undisturbed subsoil vertical temperature profile is shown that it was 28°C at a depth of 1.5 meters. The EAHE made of 66 meters of PVC tube is demonstrated a heating capacity of 13°C and a cooling capacity of 7°C and a big dependence on local climate conditions. Great potentials and thermal comfort with less energy consumption are represented by earth to air or air-ground heat exchanger in the arid regions like the South of Algeria. [ABSTRACT FROM AUTHOR]

Arid regions around the world are characterized by hard summer and winter seasons, which leads to thermal discomfort. The southwest of Algeria is classified as an arid region, where the temperature in the summer season passes sometimes 50 °C in the shade and reaches negative values in the winter season. In addition, the yearly relative humidity is below 50%. The hard thermal and hygrometric situation requires actions to fulfill the thermal comfort requirements. Air-conditioning systems are a solution, but at the same time, they are responsible for a big amount of energy consumption in the building sector. In the present paper, an experimental investigation is conducted on the performance of a coupled system: earth-to-air heat exchanger and a solar chimney. The main purpose is to reduce costs and maximize the direct effect between the two techniques. The obtained results showed that the new system was able to create two main thermal regimes in the same day. The first one is a 'heating' by increasing the outlet air temperature passing through the buried pipe and solar chimney to reach a maximum gain of 14 °C in day 3. The second thermal regime is the 'cooling' that is made by reducing the air temperature at the EAHE outlet by 11.6 °C on day 5. It is also observed that the system increases the outlet air relative humidity by 46% due to the condensation phenomena and reduces it sometimes by 45%. The recent model made of the two techniques was able to produce between 3 and 20 Watts of heating/cooling capacity at the outlet of the system. [ABSTRACT FROM AUTHOR]

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 subsoil 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. [ABSTRACT FROM AUTHOR]

Earth to air heat exchanger is a very old technique used 3000 years B.C in arid regions where that was called Qanat. In the present experimental study, the potentials of earth to air heat exchanger to provide thermal comfort for winter weather conditions in South west of Algeria described as arid region are investigated. An EAHE made of 66 meter of PVC tube and buried at 1.5 meter underground in agriculture zone equipped with 33 W fan was studied. Thermal and hygrometric analysis of air passing inside the tube form inlet to outlet was conducted. The results show the system was able to create two thermal regimes: heating regime with a gain of 13 °C (from 00h to 11h and from 17h to 23h) and cooling regime (from 12h to 16h) with 6 °C in the same day. Relative humidity was reduced by 32 % of 90 % of studied cases which stops the development of micro-organism and reducing Internal Air Quality. [ABSTRACT FROM AUTHOR]