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Journal of Energy in Southern Africa

On-line version ISSN 2413-3051
Print version ISSN 1021-447X

J. energy South. Afr. vol.22 n.4 Cape Town  2011

 

Sustainable cooling alternatives for buildings

 

 

Jaco Vorster; Robert Dobson

Department of Mechanical & Mechatronic Engineering, University of Stellenbosch, South Africa

 

 


ABSTRACT

Four sustainable alternative-energy cooling system options are investigated to quantify the actual energy that may be saved when employed in conjunction with conventional air conditioning systems. The four systems considered are active mass cooling, night flushing, roof-spraying and a roof-pond. A one-room building configuration is assumed of which the hourly cooling load and temperature is modelled for both a base case and different combinations of the four sustainable cooling alternative systems. Active mass cooling, night flushing and the roof-spray system proved to be viable options in which the cooling load of an air conditioner may be reduced to maintain a constant room temperature. The roof-spray system showed the most effective results in limiting heat gains to the one-room building and keeping peak room temperatures low.

Keywords: night flushing, active mass cooling, roof-spray, roof-pond, cooling load


 

 

Full text available only in pdf format.

 

Acknowledgements

This work was supported by KV3 Engineers and the Adaptive Engineering Group, Stellenbosch University.

 

References

Abernethy, D., (1984). Evaporative roof cooling: A simple solution to cut cooling costs, Proceedings of the Second Symposium on Improving Building Systems in Hot and Humid Climates, College Station, Texas, 24-26 September, pp. 98-102.         [ Links ]

Artmann, N., Manz, H. & Heiselberg, P, (2008). Parameter study on performance of building cooling by night-time ventilation, Renewable Energy, Vol. 33, pp. 2589-2598.         [ Links ]

ASHRAE (2005) ASHRAE Handbook - Fundamentals, American Society of Heating, Refrigerating and Air-conditioning Engineers, Atlanta, Georgia.         [ Links ]

Blondeau, P, Sperandio, M. & Allard, F, (1997). Night ventilation for building cooling in summer, Solar Energy, Vol. 61, pp. 327-335.         [ Links ]

Carrasco, A., Pittard, R., Kondepundi, S.N., & Somasundaram, S., (1987). Evaluation of a direct evaporative roof-spray cooling system, Proceedings of the Fourth Symposium on Improving Building Systems in Hot and Humid Climates, College Station, Texas, 15-16 September, pp. 94-101.         [ Links ]

Cengel, YA. and Boles, M.A., (2002). Thermodynamics: An Engineering Approach, 4th Edition, New York, McGraw Hill.         [ Links ]

Chandra, S. and Kerestecioglu, A.A., (1984). Heat transfer in naturally ventilated rooms: Data from full-scale measurements, ASHRAE Transactions, Vol. 90, Issue 1B, pp. 211-225.         [ Links ]

Chandra, S., Kaushik, S.C. & Bansal, P.K., (1985). Thermal performance of a non air-conditioned building for passive solar air-conditioning: Evaluation of roof cooling systems, Energy and Buildings, Vol. 8, Issue 1, pp. 51-69.         [ Links ]

Clark, G., (1989). Passive cooling systems, Passive Cooling, Cook J. (Ed.), MIT Press, Cambridge, MA, pp.347-538.         [ Links ]

Clements, J.A. and Sherif, S.A., (1998). Thermal analysis of roof-spray cooling, International Journal of Energy Research, Vol. 22, Issue 1, pp. 1337-1350.         [ Links ]

Corgnati, S.P. and Kindinis, A., (2007). Thermal mass activation by a hollow core slab coupled with night ventilation to reduce summer cooling loads, Building and Environment, Vol. 42, pp. 3285-3297.         [ Links ]

Dascalaki, E., Santamouris, M., Balaris, C. & Asimakopoulos, D., (1994). Natural convection heat transfer coefficients from vertical and horizontal surfaces for building applications, Energy and Buildings, Vol. 20, Issue 1, pp. 243-249.         [ Links ]

Finn, D., Connolly, D. & Kenny, P, (2007). Sensitivity analysis of a maritime located night ventilated library building, Solar Energy, Vol. 81, pp. 697-710.         [ Links ]

Geros, V., Santamouris, M., Tsangrasoulis, A. & Guarracino, G., (1999). Experimental evaluation of night ventilation phenomena, Energy and Buildings, Vol. 29, pp. 141-154.         [ Links ]

Givoni, B., (1998). Effectiveness of mass and night ventilation in lowering the indoor daytime temperatures, Energy and Buildings, Vol. 28, Issue 1, pp. 25-32.         [ Links ]

Holder, L.H., (1957). Automative roof cooling, April Showers, Washington, DC, p. 2.         [ Links ]

Incropera, FP and DeWitt, D.P, (2002). Fundamentals of Heat and Mass Transfer, 5th Edition, New York, Wiley.         [ Links ]

Jain, D., (2006). Modeling of solar passive techniques for roof cooling in arid regions, Building and Enviroment, Vol. 41, Issue 1, pp. 277-287.         [ Links ]

Jain, S.P and Rao, K.R., (1974). Experimental study on the effect of roof-spray cooling on unconditioned and conditioned buildings, Building Science, Vol. 9, Issue 9, pp. 9-16.         [ Links ].

Kharrufa, S.N. and Adil, Y, (2006). Roof-pond cooling of buildings in hot acid climates, Building and Environment, Vol. 43, pp. 82-89.         [ Links ]

Kolokotroni, M., Webb, B.C. & Hayes, S.D. (1998). Summer cooling with night ventilation for office buildings in moderate climates, Energy and Buildings, Vol. 27, pp. 231-237.         [ Links ]

Koschenz, M. and Dorer, V., (1999). Interaction of an air system with concrete core conditioning, Energy and Buildings, Vol. 30, pp. 139-145.         [ Links ]

Lehmann, B., Dorer, V. & Koschenz, M., (2007). Application range of thermally activated building systems tabs, Energy and Buildings, Vol. 39, pp. 593-598.         [ Links ]

Mills, A.F., (2000). Heat Transfer, 2nd Edition, New Jersey, Prentice Hall.         [ Links ]

Mull, T.E., (1997). HVAC Principles and Applications Manual, New York, McGraw Hill.         [ Links ]

Pfafferott, J., Herkel, S. & Jäschke, M., (2003). Design of passive cooling by night ventilation: Evaluation of a parametric model and building simulation with measurements, Energy and Buildings, Vol. 35, pp. 1129-1143.         [ Links ]

Pfafferott, J., Herkel S. & Wambsganß, M., (2004). Design, monitoring and evaluation of a low energy office building with passive cooling by night.         [ Links ]

Sodha M.S., Govind, D.P, Bansal, PK. & Kaushik, S.C., (1980). Reduction of heat flux by a flowing water layer over an insulated roof, Building and Environment, Vol. 15, pp. 133-140.         [ Links ]

Sodha, M.S., Kumar, A., Singh, U. & Tiwari, G.N., (1980). Periodic theory of an open roof-pond, Applied Energy, Vol. 7, Issue 4, pp. 305-319.         [ Links ]

Thappen, A.B., (1943). Excessive temperature in flat-top building, Refrigeration Engineering, Vol. 1, pp. 163.         [ Links ]

World business council for sustainability,         [ Links ] [Online]. Available: http://www.wikipedia.com/theinnovation-chain. [2009, October 16].

 

 

Received 10 March 201
Revised 17 June 2011