Parametric and experimental study on thermal performance of an earth–air heat exchanger (original) (raw)
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Design of an Earth Air Heat Exchanger (EAHE) for Climatic Condition ofChennai, India
Open Environmental Sciences, 2014
In the present work the ground temperature has been validated for climatic condition of Sriperumbudur near Chennai, India to evaluate thermal conductivity and diffusivity of the soil. For the evaluated thermal conductivity of the soil, an EAHE has been designed for a given dimension of room with optimized values of number of air changes, length of pipe, radius of pipe and depth at which heat exchanger to be installed below the surface of the earth. It has been observed that there is a decrease of 5-6 0 C in the outlet air temperature in summer for a number of 5 air changes with 0.10 m and 21 m optimized diameter and length of pipe respectively.
Experimental and analytical studies of earth–air heat exchanger (EAHE) systems in India: A review
Renewable and Sustainable Energy Reviews, 2013
This is the property of earth that at a depth of about 1.5 to 2 m, the temperature of ground remains almost constant throughout the year. This constant temperature is called earth's undisturbed temperature which remains higher than surface temperature of earth in winter season and vice versa in summer. For effective utilization of heat capacity of earth, the earth-air heat exchanger (EAHE) has to be designed. The EAHEs are considered as an effective passive heating/cooling medium for buildings. This is basically a series of metallic, plastic or concrete pipes buried underground at a particular depth through which the fresh atmospheric air flows and gets heated in winter and supplied to the building if at sufficiently high temperature and vice versa in summer. Till date many researchers have carried out a number of studies in designing, modeling and testing of EAHEs systems. This paper reviews on the experimental and analytical studies of EAHE systems around the world but the studies are mainly focused on EAHE systems at the Indian universities as of the end June, 2012.
Heating potential evaluation of earth-air heat exchanger system for winter season
Journal of Building Physics, 2014
Abstract --Earth-air heat exchanger (EAHE) system can be used effectively to reduce cooling energy demand of buildings in hot and dry climate. A quasi-steady state, 3-dimensional model, based on computational fluid dynamics was developed to evaluate the cooling potential of EAHE system. The simulation model was developed in CFD platform CFX 12.0. The simulation results were validated against experimental observations taken on experimental set-up installed in Bhopal (Central India). A good agreement was observed between simulation results and experimental observations with maximum values of coefficient of correlation and root mean square of percent deviation 0.997 and 8.18% respectively. The drop in air temperature and total hourly cooling energy gain obtained from experimental set-up of EAHE varies from 12.9 0 C to11.3 0 C and 0.85 to 1.87 MJ h respectively for air flow velocities of 2m/s to 5m/s. Diameter of pipe and air flow velocity were found to greatly affect the thermal performance of EAHE system.
Energy metrics of earth–air heat exchanger system for hot and dry climatic conditions of India
Energy and Buildings, 2015
The earth-air heat exchangers (EAHE) are promising technology for passive heating/cooling of buildings. The study carried out to evaluate annual thermal performance of EAHE system for hot and dry climatic conditions of Bhopal (Central India) has been presented in this paper. A quasi-steady state, 3-D model based on computational fluid dynamics (CFD) was developed to evaluate the heating/cooling potential of EAHE system. The simulation results were validated against experimental observations taken on experimental set-up installed in Bhopal (Central India). The energy metrics namely energy payback time (EPBT) and seasonal energy efficiency ratio (SEER) for EAHE system were evaluated on the basis of energy analysis of simulation results.
Experimental and numerical analysis of an earth–air heat exchanger
Energy and Buildings, 2011
Soil-to-air heat exchanger concept is one of the efficient methods to reduce the cooling effort required for any air conditioning system. In this paper, a theoretical model of soil-to-air heat exchanger has been developed to predict the air temperature in the outlet of the system during a hot atmospheric condition. This theoretical model is used to predict the subsoil temperature for a specific ambient condition in a southern part of India and also compared with the measured subsoil temperature. Performance of the soil-to-air heat exchanger system has been calculated during peak hours in summer and found to have the potential to reduce the energy required to cool the building.
International Journal of Heat and Technology
The aim of this study is to explore the performance of an Earth to Air Heat Exchanger (EAHE) and find out the utility of the device in the cooling of buildings in the hot region. The EAHE cooling potential was experimentally investigated for a placement in Biskra, a city located in the south east of Algeria. A cylindrical tube of PVC in the serpentine form having an internal diameter of 0.110m and a total length of 56m is buried at 3m depth with a slope of 2% at Biskra University. The temperature readings of soil, external air and a buried duct at several positions were recorded during the period of May and September of the year 2013. Results showed that EAHE cooling potential (discrepancy between the inlet temperature (ambient) and the outlet temperature of the EAHE) was found promising as it could exceed 15 °C. The duration of operation of the heat exchanger does not influence the outlet temperature. EAHE is very useful to refresh buildings during spring and early summer, but it can just be used for pre-cooling in the rest of summer and autumn seasons. Moreover, a database was developed about the temperatures of the soil, external air and at the outlet of the device which may be useful for researchers in the future.
The Thermal Performance of Earth Air Heat Exchanger
This paper investigates the Experimental study on the thermal performance of earth air heat exchanger. The temperature of the ground depth of 2m and above remains nearly constant throughout the year .this undisturbed temperature which remains constant is lower than the outside temperature in winter, higher than the outside temperature in winter. In summer the hot atmospheric air is drawn through buried pipes with help of blower and is cooled and during winter the cool air is heated before used for ventilation. A temperature difference of 8 o C to 10 o C is observed during the summer.
Earth Air Heat Exchanger Performance in Summer Cooling For Various Supply Air Conditions — A Review
international journal of engineering trends and technology, 2016
There is a growing interest in heating and cooling systems based on renewable energy. This is the property of earth ground the below about 2.5 to 3 m, the temperature of ground remains nearly constant throughout the year. This constant temperature is called undisturbed temperature of earth. However, a good visualize the undisturbed ground temperature, for a correct interpretation of the geothermal heat exchanger. The undisturbed temperature is very important yourself, which remains higher than the outside temperature in winter and lower than the outside temperature in summer. The EAHEs are considered as an effective passive heating/cooling medium for buildings. It is basically a series of metallic, plastic or concrete pipes buried underground at a particular depth through which the fresh atmospheric air flows and gets heated in winter and supplied to the building if at sufficiently high temperature and vice versa in summer. Until now, many researchers have conducted a series of stud...
The earth to air heat exchangers (EAHE) is effective passive cooling and heating techniques for buildings. This paper studies numerically the effect of some design and environmental parameters (moist content of soil, pipe material and thickness of pipe wall) on the overall performance of EAHE system. Three types of soil were selected (dry soil, moist soil and saturated soil) with two pipe materials PVC and steel and three thicknesses of pipe wall (2, 3 and 6 mm). This numerical study has been done for summer and winter seasons according to the weather conditions for Nasiriyah city in southern of Iraq. First the built numerical model was validated against experimental model and the results of comparison showed good agreement. After the validation the overall performance of EAHE system with selected parameters was analyzed with ranges of air velocity, inlet temperature and pipe length of 50 m. The simulated results showed that the very moist or saturated soil gives the best overall performance of EAHE system compare with other soils, Furthermore there is no significant effect of pipe material and wall thickness on the overall performance.
A Review on Earth-Air Heat Exchanger
2018
The demands of cooling energy & the thermal comfort requirements are rapidly increasing day by day due to global warming effect. The temperature of earth at a certain depth about 1.5 m to 3 m the temperature of ground remains nearly same throughout the year. This temperature remains more than the outside temperature in winter season and lowers than the outside temperature in summer season. The earth air heat exchanger is the possible approach to reduction of heat loss and for the thermal comfort improvement. Earth air heat exchanger or earth tube heat exchanger is a device used to produce heating effects in winter and cooling effects in summer using the ground or soil as a source or sink. When ambient air is drawn through buried pipes, the air is cooled in summer and heated in winter, before it is used for ventilation. The earth air heat exchanger can full fill in both purposes heating in winter and cooling in summer. This paper focus on the effects of various parameters on performa...