A new computational modeling to predict the behavior of Earth-Air Heat Exchangers

Abstract The use of renewable energy sources to improve the thermal conditions of built environments and hence decreasing the consumption of conventional energy is an important aspect to design a sustainable building. Within this context, it is possible to harness the solar energy that reaches the Earth's surface and is stored by the soil as thermal energy. To do so, the Earth-Air Heat Exchanger (EAHE) device can be employed, consisting of a buried duct through which the external ambient air is insufflated. The flowing air exchanges heat with surround soil, and leaves the device with a milder temperature compared to its input temperature. The main goal of this work was to present a new computational modeling to predict the thermal behavior of EAHE. This new numerical model has the advantage of needing a lower computational effort, allowing the study about the influence of operational and constructive parameters, as well as, the application of geometric optimization methods in EAHE. A case study was developed where influence of the installation depth in the thermal potential of an EAHE was investigated. The results are in agreement with those found in literature; however they were obtained with a reduction in processing time of almost 45%.

[1]  S. Kyritsis,et al.  The performance of a greenhouse heated by an earth-air heat exchanger , 1986 .

[2]  A. Bejan.  Convection Heat Transfer , 1984 .

[3]  N. K. Bansal,et al.  Temperature distribution inside ground for various surface conditions , 1981 .

[4]  Alireza Khaligh,et al.  Energy Harvesting: Solar, Wind, and Ocean Energy Conversion Systems , 2009 .

[5]  C. Gauthier,et al.  Numerical simulation of soil heat exchanger-storage systems for greenhouses , 1997 .

[6]  Joaquim Vaz.  Estudo experimental e numérico sobre o uso do solo como reservatório de energia para o aquecimento e resfriamento de ambientes edificados , 2011 .

[7]  Fariborz Haghighat,et al.  Convective heat transfer prediction in large rectangular cross-sectional area Earth-to-Air Heat Exchangers , 2009 .

[8]  F. Lien,et al.  Assessment of turbulence-transport models including non-linear rng eddy-viscosity formulation and second-moment closure for flow over a backward-facing step , 1994 .

[9]  D. N. Asimakopoulos,et al.  Modelling the thermal performance of earth-to-air heat exchangers , 1994 .

[10]  T. Gatski,et al.  Modelling the pressure–strain correlation of turbulence: an invariant dynamical systems approach , 1991, Journal of Fluid Mechanics.

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

[12]  M. S. Sodha,et al.  Thermal performance of underground air pipe: Different earth surface treatments , 1991 .

[13]  R. Henkes,et al.  The Reynolds-stress model of turbulence applied to the natural-convection boundary layer along a heated vertical plate , 1992 .

[14]  Baruch Givoni,et al.  Earth temperatures and underground buildings , 1985 .

[15]  D. Wilcox.  Turbulence modeling for CFD , 1993 .

[16]  Weeratunge Malalasekera,et al.  An introduction to computational fluid dynamics - the finite volume method , 2007 .

[17]  Jyotirmay Mathur,et al.  Performance analysis of earth–pipe–air heat exchanger for summer cooling , 2010 .

[18]  G. Mihalakakou,et al.  On the cooling potential of earth to air heat exchangers , 1994 .

[19]  Jyotirmay Mathur,et al.  Performance analysis of earth–pipe–air heat exchanger for winter heating , 2009 .

[20]  Joaquim Vaz,et al.  Development of Simplified Numerical Model for Evaluation of the Influence of Soil-Air Heat Exchanger Installation Depth over Its Thermal Potential , 2012 .

[21]  R. Gaspar,et al.  Simulation of greenhouse microclimate produced by earth tube heat exchangers , 1989 .

[22]  Joaquim Vaz,et al.  Experimental and numerical analysis of an earth–air heat exchanger , 2011 .