Performance analysis of an earth-to-air heat exchanger assisted by a wind tower for passive cooling of buildings in arid and hot climate

Abstract In this paper, a new design of passive cooling system which consists in an Earth-to-Air Heat Exchanger (EAHE) assisted by a wind tower is presented. This system is intended for the summer cooling in hot and arid regions of Algeria. A transient analytical model was developed in order to investigate the influence of design parameters on the performance of the EAHE. The model of the EAHE is validated against both theoretical and experimental data carried out by other authors. Since it is well-known that the performance of the EAHE systems is more influenced by the air flow velocity, another model was presented to predict the air velocity inside the buried pipe. Moreover, a burying depth of 2 m was adopted and the period under consideration is July where the ambient temperature exceeds 45 °C. This study was also extended to examine the behaviour of system during the whole year. In addition, a sensitivity survey was curried out to investigate the influence of tower and pipe dimensions on the air flow velocity and the performances of the EAHE. Results showed that the wind tower dimensions (height, cross section) have not an important impact compared to the pipe dimensions (length, diameter). It is found that a tower with a total height of 5.1 m and a cross section area of 0.57 m 2 can generate an air flow rate of 592.61 m 3 /h. Furthermore, it has been also observed that the daily cooling potential reached a maximum of 30.7 kW h corresponding to a pipe length of 70 m. The cooling effectiveness of the system is compared to that of traditional passive cooling system consisting in a wind tower with wet surfaces. The results indicated that the ambient air after passing through the wind tower coupled to the EAHE is colder than of that of the leaving the conventional cooling tower.

[1]  Giorgia F. Cortinovis,et al.  A systemic approach for optimal cooling tower operation , 2009 .

[2]  Mehdi N. Bahadori,et al.  An improved design of wind towers for natural ventilation and passive cooling , 1985 .

[3]  Masud Behnia,et al.  Enhancing performance of wet cooling towers , 2007 .

[4]  Ursula Eicker,et al.  Limits and potentials of office building climatisation with ambient air , 2006 .

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

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

[7]  Mehdi N. Bahadori,et al.  Viability of wind towers in achieving summer comfort in the hot arid regions of the middle east , 1994 .

[8]  Miroslav Bojic,et al.  Numerical simulation, technical and economic evaluation of air-to-earth heat exchanger coupled to a building , 1997 .

[9]  G. Mihalakakou,et al.  Use of the ground for heat dissipation , 1994 .

[10]  Mohsen Mazidi,et al.  Experimental investigation of new designs of wind towers , 2008 .

[11]  Stéphane Thiers.  Bilans énergétiques et environnementaux de bâtiments à énergie positive , 2008 .

[12]  M. S. Sodha,et al.  Optimization of pipe parameters of an underground air pipe cooling system , 1993 .

[13]  Hamid Saffari,et al.  Two-phase Euler-Lagrange CFD simulation of evaporative cooling in a Wind Tower , 2009 .

[14]  S. Thepa,et al.  Cooling performance assessment of horizontal earth tube system and effect on planting in tropical greenhouse , 2014 .

[15]  Hua Su,et al.  A numerical model of a deeply buried air–earth–tunnel heat exchanger , 2012 .

[16]  Martin Belusko,et al.  A model for integrating passive and low energy airflow components into low rise buildings , 2012 .

[17]  Etienne Wurtz,et al.  Modelling earth-to-air heat exchanger behaviour with the convolutive response factors method , 2009 .

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

[19]  Mustafa Inalli,et al.  A techno-economic comparison of ground-coupled and air-coupled heat pump system for space cooling , 2007 .

[20]  B. J. Vickery,et al.  Evaluation of pressure coefficients and estimation of air flow rates in buildings employing wind towers , 1986 .

[21]  V. A. Reyes,et al.  A study of air flow and heat transfer in building-wind tower passive cooling systems applied to arid and semi-arid regions of Mexico , 2013 .

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

[23]  Jyotirmay Mathur,et al.  CFD analysis based parametric study of derating factor for Earth Air Tunnel Heat Exchanger , 2013 .

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

[25]  Bruno Peuportier,et al.  Thermal and environmental assessment of a passive building equipped with an earth-to-air heat exchanger in France , 2008 .

[26]  Laura Bellia,et al.  Earth-to-air heat exchangers for Italian climates , 2011 .

[27]  Arnold Janssens,et al.  Thermo-hydraulic design of earth-air heat exchangers , 2003 .

[28]  Azeddine Belhamri,et al.  Performance analysis and improvement of the use of wind tower in hot dry climate , 2011 .

[29]  Vitor A. F. Costa,et al.  Thermodynamic analysis of building heating or cooling using the soil as heat reservoir , 2006 .

[30]  Georgios Kokogiannakis,et al.  Theoretical and practical evaluation of an earth-tube (E-tube) ventilation system , 2011 .

[31]  Luis Pérez-Lombard,et al.  A review on buildings energy consumption information , 2008 .

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

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

[34]  Mehmet Esen,et al.  Experimental evaluation of using various renewable energy sources for heating a greenhouse , 2013 .

[35]  J. J. Correia da Silva.  Passive downdraught evaporative cooling applied to an auditorium , 2005 .

[36]  Bert Blocken,et al.  Energy saving potential of night ventilation: Sensitivity to pressure coefficients for different European climates , 2014 .

[37]  Mehmet Esen,et al.  Temperature distributions in pavement and bridge slabs heated by using vertical ground-source heat pump systems , 2013 .

[38]  G. Mihalakakou,et al.  On the ground temperature profile for passive cooling applications in buildings , 1996 .

[39]  Ali A. Badran,et al.  Performance of cool towers under various climates in Jordan , 2003 .

[40]  Vali Kalantar,et al.  Numerical simulation of cooling performance of wind tower (Baud-Geer) in hot and arid region , 2009 .

[41]  Kwang Ho Lee,et al.  The cooling and heating potential of an earth tube system in buildings , 2008 .

[42]  Baruch Givoni,et al.  Cooled soil as a cooling source for buildings , 2007 .

[43]  Michele De Carli,et al.  The design and environmental evaluation of earth-to-air heat exchangers (EAHE). A literature review , 2013 .

[44]  D. N. Asimakopoulos,et al.  Modelling the earth temperature using multiyear measurements , 1992 .

[45]  M. S. Sodha,et al.  Parametric and experimental study on thermal performance of an earth–air heat exchanger , 2006 .

[46]  Nyuk Hien Wong,et al.  Influences of ambient air speed and internal heat load on the performance of solar chimney in the tropics , 2014 .

[47]  Jyotirmay Mathur,et al.  Performance analysis of integrated earth–air-tunnel-evaporative cooling system in hot and dry climate , 2012 .