‘Derating Factor’ new concept for evaluating thermal performance of earth air tunnel heat exchanger: A transient CFD analysis

Bansal, Vikas; Misra, Rohit; Agarwal, Ghanshyam Das; Mathur, Jyotirmay

doi:10.1016/j.apenergy.2012.07.027

Cited by 58 publications

(29 citation statements)

References 36 publications

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“…Several experimental and/or numerical studies on the EAHX cooling performances in hot climate, such as one of Marrakech (Morocco), have been performed through the world [9][10][11][14][15][16][17][18][19][20][21]. All of these studies concluded on the very interesting performances of the EAHX for air cooling, although these performances depend on many parameters, in particular the soil properties and the local climate.…”

Section: Experimental Projects and Guidelinesmentioning

confidence: 99%

“…Most of these models are based on finite differences. Some of them are limited to the description of only one ""typical"" pipe [14,18,[28][29][30][31]. Others deal with several parallel running pipes, with or without possibility to treat more complicated cases than steady state flow rate, homogenous and laterally adiabatic soils, or sole sensible heat exchange [32][33][34][35].…”

Section: Modelsmentioning

confidence: 99%

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Experimental and numerical study of an earth-to-air heat exchanger for air cooling in a residential building in hot semi-arid climate

Khabbaz

Benhamou

Limam

et al. 2016

Energy and Buildings

110

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Experimental and numerical study of an earth-to-air heat exchanger for air cooling in a residential building in hot semi-arid climate, Energy and Buildings http://dx.doi.org/10. 1016/j.enbuild.2016.04.071 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. 3 ABSTRACT This work deals with an experimental and numerical study of an Earth-to-Air Heat Exchanger (EAHX) for air cooling, connected to a residential building located in Marrakech (Morocco) which climate is a hot semi-arid one. The EAHX consists of three parallel PVC pipes of 72 m length each and 15 cm inside diameter, buried at 2.2-3.2 m depth. Each pipe is equipped with a fan, which blows treated air into the building. The experimental study consists of summer monitoring of the EAHX via measurements of air temperature and humidity throughout the exchanger, as well as at its inlet and outlet to the building for two fixed values of the airflow rate. The experimental results show that the EAHX is a good semipassive system for air refreshment, as the recorded blown air temperature into the building is quasi-constant at 25 °C with air humidity around 40%, even though the outside temperature reaches more than 40 °C. Furthermore, the reduction of daily and annual air temperature amplitudes is characterized by an exponential drop as a function of pipe length. The characteristic length is found to be around 20m and 70m respectively for the daily and annual air temperature amplitudes reduction. Moreover, it is shown that the design guidelines from literature cannot straightforwardly be applied to an EAHX which is subject to meteorological disturbance from the upper surface and/or which is not operated all year round, for which numerical simulation with a validated models remains necessary. 1 EXPERIMENTAL AND NUMERICAL STUDY OF AN EARTH-TO-AIR HEAT EXCHANGER FOR AIR COOLING INOn the other hand, dynamic simulations of the EAHX using TRNSYS software (TYPE 460) were performed with one pipe or three pipes continuously running. Good agreement was found between the simulation and experimental results. Simulation results show that the EAHX can perform a maximum drop of air temperature as high as 19.5 °C and 18.3 °C respectively for an EAHX with one and three pipes. The achieving specific cooling capacity is 58 W/m 2 (one pipe) and 55 W/m 2 (three pipes) obtained for air temperatures of 25 °C and 26 °C respectively, at the EAHX outlet and 44.6 °C at its inlet.

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Section: Experimental Projects and Guidelinesmentioning

confidence: 99%

Section: Modelsmentioning

confidence: 99%

Experimental and numerical study of an earth-to-air heat exchanger for air cooling in a residential building in hot semi-arid climate

Khabbaz

Benhamou

Limam

et al. 2016

Energy and Buildings

110

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show abstract

“…12 In order to analyze the self-recovery ability during the nonworking time, the performance of 13 EAHE under both continuous and intermittent operation conditions were discussed firstly. The 14 research can be utilized to improve EAHE operation management. 15 2 Mathematic Modeling 16 2.1 Soil temperature modeling 17 Ground soil is the energy resource of EAHE which supplied cooling or heating energy for air 18 inside the tube.…”

mentioning

confidence: 99%

“…A very useful 12 review paper on applications of CFD in the field of heat exchangers was published. It is 13 concluded that CFD is an effective tool for predicting the behavior and performance of a wide 14 variety of heat exchangers [10]. Misra et al used CFD software to study the effect of soil thermal 15 conductivity, duration of continuous operation, pipe diameter and flow velocity on the thermal 16 performance of EAHE based on parametric method.…”

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Investigation on soil thermal saturation and recovery of an earth to air heat exchanger under different operation strategies

Niu

2015

Applied Thermal Engineering

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Analysis of an earth‐to‐air heat exchanger for enhanced residential thermal comfort

Dewangan,

Shukla,

Salhotra

et al. 2024

Env Prog and Sustain Energy

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It is well known that a massive demand for thermal comfort has resulted in a sharp rise in energy use for residential space heating and cooling. This article presents numerical simulations of a room coupled with an earth‐to‐air heat exchanger system operating at the climatic condition of 21.2497° N, 81.6050° E for both summer and winter seasons. The present study involves an estimate of monthly variations in soil temperature at different depths and a suitable geometrical arrangement of pipe is proposed. The thermal performance of the earth‐to‐air heat exchanger system in terms of the outlet air temperature and effectiveness has been calculated. It is shown that with an effectiveness of 0.77 in summer and 0.78 in winter, the present EAHE system reduces the ambient air temperature from 38 to 28.2°C in the summer and it rises from 13 to 22.9°C in winter, respectively. Finally, an improvement in the thermal comfort condition of the room exposed to the solar radiation has been examined at different time intervals and different heights of the room. During the summer the room temperature dropped by 4.2°C while in winter it rose by 5.2°C. Furthermore, the environmental effects of system have been evaluated, showing energy savings of 3.90 kWh/day during summer and 4.83 kWh/day during winter leading to a decrease in CO2 emissions of 6.13 kg/day in summer and 7.59 kg/day in winter.

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‘Derating Factor’ new concept for evaluating thermal performance of earth air tunnel heat exchanger: A transient CFD analysis

Cited by 58 publications

References 36 publications

Experimental and numerical study of an earth-to-air heat exchanger for air cooling in a residential building in hot semi-arid climate

Experimental and numerical study of an earth-to-air heat exchanger for air cooling in a residential building in hot semi-arid climate

Investigation on soil thermal saturation and recovery of an earth to air heat exchanger under different operation strategies

Analysis of an earth‐to‐air heat exchanger for enhanced residential thermal comfort

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