Performance analysis of earth–pipe–air heat exchanger for summer cooling

Abstract Earth–pipe–air heat exchanger (EPAHE) systems can be used to reduce the cooling load of buildings in summer. A transient and implicit model based on computational fluid dynamics was developed to predict the thermal performance and cooling capacity of earth–air–pipe heat exchanger systems. The model was developed inside the FLUENT simulation program. The model developed is validated against experimental investigations on an experimental set-up in Ajmer (Western India). Good agreement between simulated results and experimental data is obtained. Effects of the operating parameters (i.e. the pipe material, air velocity) on the thermal performance of earth–air–pipe heat exchanger systems are studied. The 23.42 m long EPAHE system discussed in this paper gives cooling in the range of 8.0–12.7 °C for the flow velocities 2–5 m/s. Investigations on steel and PVC pipes have shown that the performance of the EPAHE system is not significantly affected by the material of the buried pipe (pipe). Velocity of air through the pipe is found to greatly affect the performance of EPAHE system. The COP of the EPAHE system discussed in this paper varies from 1.9 to 2.9 for increase in velocity from 2.0 to 5.0 m/s.

[1]  Hongxing Yang,et al.  Numerical analysis and experimental validation of heat transfer in ground heat exchangers in alternative operation modes , 2008 .

[2]  Shengwei Wang,et al.  Modelling and evaluation of cooling capacity of earth-air-pipe systems , 2007 .

[3]  Thierry Boulard,et al.  Heat and water vapour transfer in a greenhouse with an underground heat storage system part I. Experimental results , 1989 .

[4]  Dennis L. Loveday,et al.  The cooling potential of earth-air heat exchangers for domestic buildings in a desert climate , 2006 .

[5]  N. K. Bansal,et al.  Evaluation of an earth—air tunnel system for cooling/heating of a hospital complex , 1985 .

[6]  S. C. Kaushik,et al.  Performance evaluation and energy conservation potential of earth–air–tunnel system coupled with non-air-conditioned building , 2003 .

[7]  G. Mihalakakou,et al.  On the application of the energy balance equation to predict ground temperature profiles , 1997 .

[8]  L. Montoro,et al.  A one-dimensional transient analytical model for earth-to-air heat exchangers, taking into account condensation phenomena and thermal perturbation from the upper free surface as well as around the buried pipes , 2008 .

[9]  D. N. Asimakopoulos,et al.  Parametric prediction of the buried pipes cooling potential for passive cooling applications , 1995 .

[10]  Viorel Badescu,et al.  Simple and accurate model for the ground heat exchanger of a passive house , 2007 .

[11]  M. K. Ghosal,et al.  Modeling and comparative thermal performance of ground air collector and earth air heat exchanger for heating of greenhouse , 2005 .