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In order to utilise naturally stored heat or cold from the ground, seasonal temperature variations are required. The reason is that the ground temperature is then warmer than the air temperature during winter and colder during summer. The heating and cooling demand in North Africa varies considerably with the greatest cooling demand in the East and...
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Citations
... Moummi et al. [17] presented an analytical model of the earth cooling pipe, the results were compared with experimental data obtained in south Algeria (university of Biskra). Amara et al. [18] studied the ancient Fouggara system and investigated its possible use as a source for heating, cooling and ventilation of buildings. The Fouggara consists of: the source where the water seeps into the channel from a ground water source, an underground channel which brings the water to its intended destination, an over ground channel which leads to a network of channels feeding the water to particular areas or fields for irrigation. ...
The well-known traditional vapor compression refrigeration cycle is considered to be the most effective technique used in the field of refrigeration and air-conditioning systems. It’s used almost in every facility including industrials, homes and food storages. There are some environmental hazards concerning the use of vapor-compression cycles such as global warming and ozone layer depletion mainly due to refrigerant's leakages. However, it's still considered as a leading technology for its capability of producing high cooling and heating powers with great coefficient of performance. The present work represents an experimental investigation of the effect of the condenser's temperature on the thermal performance of a conventional vapor compression refrigeration cycle. The geothermal cooling technique was introduced and utilized for cooling the temperature of the condenser that operates in harsh climate conditions. The experiment was performed using two additional heat exchangers for enabling heat exchange with geothermal temperature. The first heat exchanger (primary HX1) was connected directly to the condenser while the other one (secondary HX2) was installed inside the geothermal hole intended for heat exchange with the geothermal temperature. These exchangers (HX1 and HX2) were thermally connected via two PVC tubes with straight water circulating inside them (using a DC water pump). The experimental results proved the success of the current utilized method in improving the thermal performance of the system. Cooling the condenser via geothermal cooling has led to a considerable reduction in the temperature of the refrigerant and improved the overall performance of the cycle. The experimental apparatus showed an increase in both cooling capacity and COP by 25% and 21.5%, respectively. In addition, a considerable enhancement in the temperature of the evaporator was accomplished to reach a minimum temperature of 14.5ºC.
... Operational parameters of these type heat exchangers have been widely studied throughout the world over the past decade. For example, studies conducted in Europe (Tzaferis et al. 1992, Badescu et al. 2007, Benkert et al. 1997, Congedo et al. 2019, Greco & Masselli 2019, CIS countries (Filatov & Volodin 2013), Africa (Sehli et al. 2012, Amara et al. 2011, Hamdi et al. 2018, Serageldin et al. 2016, Asia (Sanusi 2012, Ariffin et al. 2014, Misra et al. 2018, Agrawal et al. 2019 and America (Díaz-Hernández et al. 2020, Krarti & Kreider 1996. ...
... An important characteristic that used in the calculations is the climatic data on the temperature of the soil depending on the depth and its thermophysical properties (Table 3). In the literature, it is possible to find data on soil temperatures for a number of countries (Díaz-Hernández 2020, Benkert et al. 1997, Sanusi 2012, including and Ukraine (Nakorchevsky & Belyaeva 2005), as well as its thermophysical properties (Benkert et al. 1997, Congedo et al. 2019, Amara et al. 2011, Rouag et al. 2018, Basok et al. 2009). In the works it is usually accepted the assumption that soil is a homogeneous and isotropic medium. ...
This article is devoted to the analysis of the heat engineering characteristics of the operation of an Earth-to-Air Heat Exchanger, EAHE, with a circular cross-sectional shape, which is a component of the geothermal ventilation system. The authors analyzed literature sources devoted to the research of heat exchangers of the soil-air type of various designs and for working conditions in various soils. Much attention is paid to the issues of modeling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. The results of these studies are the basis for the development of a method for determining the optimal diameter of an EAHE under operating conditions for soil in Kyiv, Ukraine.
... Теплотехнічні параметри й експлуатація теплообмінників зазначеного типу вже достатньо давно досліджуються у всьому світі. Так наприклад, проведено дослідження в Європі [3,4,5,6], Африці [7,8,9], Азії [10,11] та Америці [12]. В Україні також ведуться роботи в цьому напрямку [13,14]. ...
The aim of this work is to develop a numerical model of the year-round operation of an earth-to-air heat exchanger (EAHE) with a circular cross-sectional shape with further its validation based on the obtained experimental data. We consider that these studies can form the basis for the development of methods for calculating and designing geothermal ventilation systems for climate conditions of Ukraine. The analysis of literature sources showed that now there are quite a lot of studies devoted to the issues of geothermal ventilation. The results of such heat exchanger modeling with various geometric data and which operate in their authentic soils under various hydraulic regimes and that are located at different depths are widely presented. However, these studies do not allow obtaining generalized patterns of heat transfer during the operation of the heat exchangers and the influence of the geometric parameters of the heat exchanger on the operation of the geothermal ventilation system as a whole. Much attention is paid to the issues of modelling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. To conduct experimental research on the operation of the geothermal ventilation system at the Institute of Engineering Thermophysics of the National Academy of Sciences of Ukraine an experimental stand was created. This stand is designed to study thermophysical processes during the operation of a geothermal ventilation system elements. The results of these studies are the basis for the development of a method for determining the optimal diameter of the earth-to-air heat exchanger under operating conditions for soil in Kyiv, Ukraine.
... Heat exchangers of this type have long been studied around the world. Thus some studies have been carried out in Europe [2,3,4,16], Commonwealth of Independent States (CIS) countries [5], Africa [6,7], Asia [8,13], and America [9]. In Ukraine, work in this area is at the initial stage of development. ...
... In contrary, only 4% of R dwellings were mechanically ventilated. Unlike R dwellings, many M dwellings had Canadian well, which takes the advantage of ground heating and cooling [54]. Fig. 1a presents the comparison between the two building types in terms of primary energy use for space heating. ...
We performed the first large-scale investigation of indoor air quality (IAQ), energy and occupant behavior and satisfaction, in 650 energy-efficient dwellings in western Switzerland. The investigation included comparative assessment of 217 green-certified Minergie (M) and 433 energy-renovated (R) dwellings. Data were collected through a combination of questionnaire survey of building characteristics and occupancy symptoms/satisfaction, as well as field measurements of radon, total volatile organic compounds (TVOC), formaldehyde and fungi. The results showed that 90% of M dwellings relied on renewable and low-carbon energy sources for space and water heating, as compared to only 40% of R dwellings. The annual electricity consumptions of M and R dwellings were similar (~33 kWh/m2), however, R dwellings consumed more gas and heating oil, thus contributing more to greenhouse gas emissions. Concentration of sampled air pollutants in the two dwelling types was generally below the maximum guideline values. Interestingly, concentration of all air pollutants was significantly lower in M relative to R dwellings: Radon (48 vs. 91 Bq/m3), TVOC (167 vs. 259 μg/m3), formaldehyde (12 vs. 15 μg/m3) and fungal colony forming units (33 vs. 48 CFUs). Statistical comparisons revealed that residents of naturally ventilated R dwellings tended to open window more frequently, while occupants of M dwellings relied on mechanical ventilation. We found no differences in occupant satisfaction and self-reported symptoms between the two dwelling types. The findings of this study are of potential utility for interpreting impacts of growing building energy renovation initiatives on indoor air quality, ventilation design and occupant satisfaction.
... The ambient air then approaches the temperature of the Cavern (~13°C) during the passage through the ground before used for ventilation, heating, and cooling of buildings that can reduce energy consumption inside the building [14]. Another old existing system has been studied called Fouggara situated in the desert of Algeria [15]. This study shows the feasibility of using this system for heating and cooling buildings where the temperature inside the system is constant about 21°C during the year Figure 4 The 2nd International Conference on Green Civil and Environmental Engineering ...
Abstract
The unbalance between supply and demand of heat can be managed by thermal energy storage (TES). For large-scale systems the underground is used as storage medium or storage volume. Aquifer storage (ATES) is most suitable for very large applications, Borehole storage (BTES) the most general system in all scales and the rock cavern storage (CTES) is best suited for extremely high loading/extraction loads. The construction of any of these systems requires knowledge about site-specific properties of the ground i.e. geology and groundwater conditions. Current paper gives a brief review of the potential and advantage of Underground Thermal Energy Storage (UTES) technology utilization in buildings for the hard climate.
... The same idea was applied by Algerian desert inhabitants in the region of Adrar. The technic was called the Fougaraha and invented to provide water supply and precooling or ventilation for the houses [3]. In the same time, the people of Benni Abass (south of Bechar) build their own summer chamber under their basement to benefice from less few degrees in summer season in comparison with outside air (sometimes reach 50 °C) and serve as food storage in winter. ...
Ground vertical temperature profile at various depths is a major key in designing phase of the use of earth heating and cooling techniques for buildings, offices and greenhouses like earth to air heat exchanger (ETAHE), Earth-Air Tunnel (EAT), Ground Air Collector (GAC) and water Quanat. Annual undisturbed soil temperature is very important parameter to investigate earth to air potentials. The present experimental study was conducted in two different sites in South-west of Algeria, in the city of Bechar (arid region) starting from ground surface to 1.5 m depth. The obtained results show that at the ground surface temperature was 35.2 °C for both sites. At 1.5 m of depth, the temperature was 29.2 °C and 28 °C in site n°1 and n°2 respectively. Temperature values remain constant after 70 seconds. The study results serve as a benchmark for other studies and help researchers interested to study this renewable energy source.
... Many authors found that due to its high thermal inertia, the soil can be used as a heat sink in summer time and as a heat source in wintertime [17][18][19] . The temperature of the soil remains constant over a depth of 4 m [20,21] . ...
... The difference between the external temperature and the air temperature at the exit of wet and dry lines referred to the average day of summer (Figure 7) confirm the results of different researches [18,19,39] . ...
Earth-to-air heat exchangers (EAHE) can reduce the energy consumption required for heating and cooling of buildings. The composition and the thermal characteristics of the soil influence the heat exchange capacity, and the soil moisture can furthermore affect thermal performance of EAHE. The aim of this study was to compare the thermal performance of EAHE in dry and artificially wetted soil. Tests were carried out in the Basra Province (Iraq), in a semi-desert
area. Two experimental EAHE were built in a poultry barn and tested from June 2013 to September 2013. The pipe exchangers were buried at 2 m deep. One heat exchanger operated in dry soil (DE), while the other one operated in artificially wetted soil (WE). In the WE system, a drip tubing placed 10 cm above the air pipe wetted the soil around the exchanger. Air temperatures at the inlet and at the outlet of both the exchangers as well as soil temperature at 2 m deep were continuously
monitored. The experimental results confirmed that wetting the soil around EAHE improves the general heat exchange efficiency. The coefficient of cooling performance (COP) of the earth-to-air heat exchangers system was evaluated on the basis of the ratio between the heat removed from the air or added to the air and the energy input. During the day, with an average COP of 6.41, the WE system cooled the air more than the DE system, which reported a value of 5.07. On average, in the hottest hours of the day, the outlet temperature of the WE was 37.35°C while in the DE it was 38.91°C. Moreover, during the nighttime, the WE system warmed the air more than the DE system.
... An experimental investigation done by Mongkon et al. [2] showed the possibility of implementation of EATHE in a tropical climate. Amara et al. [3] determined the viability of EATHE for air-conditioning in a building in Adrar, Algeria. Ozgener et al. [4] conducted an exergoeconomic test to determine the optimal design of an EATHE in Izmir, Turquia. ...
Thermal performance of Earth Air Tunnel Heat Exchanger (EATHE) system is found to be highly dependent on thermal properties of soil and soil with poor thermal properties require longer buried pipe for desired heat exchange between air and sub-soil. In densely populated country like India, EATHE systems are rarely used due to the limited ground space (higher aspect ratio in terms of length) in most of the residential and commercial applications. Therefore, in this paper, problem of space limitation for the installation of straight EATHE system is attempted by proposing new spiral shaped EATHE system. The developed EATHE systems were used to determine cooling and heating potential individually and COP were 5.94 and 6.24 in summer; 1.92 and 2.11 in winter for straight and spiral respectively. A transient numerical model has been developed to investigate the performance of both systems. The COP were 4.23 and 4.48 in summer; 5.0 and 5.16 in winter for straight and spiral respectively. The experimental and numerical results suggested that the thermal performance of these two systems are comparable can be interchanged based on available site conditions.
... One disadvantage of experimental studies is the cost and the time that is required. Among experimental studies, Amara et al. analyzed the viability of an EAHE in a building in Adrar, Algeria [31]. From the study, the authors concluded that the air at the outlet of the EAHE tends to reach the average year temperature and reducing the thermal impact from the outdoor temperature. ...
