Numerical Study of the Effects of Speed and Place of Ceiling Fans on Thermal Comfort and Reducing Energy in Office Buildings

Document Type : Research Article

Authors

Mechanical Engineering Department, University of Kashan, Kashan, Iran

Abstract

The main aim of the present study is to investigate the effects of speed and place of ceiling fans on thermal comfort parameters (predicted mean vote and predicted percentage of dissatisfied) and energy expenses in two different office rooms with a certain geometry in winter using district heating system. In all of the models, the regime of a flow is turbulent and governing equations are solved by finite volume method and SIMPLE algorithm. Based on the results, using ceiling fans in winter (heating system) has a considerable influence on the improvement of buildings thermal comfort and reducing consumption of energy. By using ceiling fans the effective temperature of room increases and therefore radiator energy consumption decreases. Furthermore, the results show that the location of ceiling fan does not have any effect on room effective temperature and residents’ thermal comfort. According to the results, predicted mean vote and predicted percentage of dissatisfied parameters improve by turning ceiling fans on and increasing fan normal air velocity. But, the operation of fan leads to cooling system after a certain velocity and it is not acceptable for the heating system. Finally, the CF.A case with p(x)=1.0 m, V=0.2 m/s and Tradiator=51oC, and CF.B.1 case with p(x)=2.5 m, V=0.27 m/s and Tradiator=37oC, by providing thermal comfort conditions and reducing consumption of energy about 58% and 73%, respectively are reported as optimal cases. 

Keywords

Main Subjects

References

[1] P.O. Fanger, Thermal comfort analysis and application environmental engineering. Mcgrawhill book-company, Newyork, 1972.
[2] European Union, The new directive on the energy performance of buildings, 3rd edition, 2002.
[3] M. Tietel, J. Tanny, A note on energy saving in heated enclosures, Building and environment, 31(6) (1996) 537–540.
[4] A. H. Moghadam, A. Keshavarzvalian, N. Jahantigh, The Optimization of Heat Transfer Distribution in a Heated Room Using Convective Thermal Panels for Achievement of Thermal Comfort, AmirKabir Journal of Science & Research Mechanical Engineering, 45(1) (2013) 63–73.
[5] M. Maerefat, N. Morovati, Analysis of thermal comfort in space equipped with stream ventilation and radial cooling ceiling, Modares Mechanical Engineering, 13(11) (2013) 41–54.
[6] M. H. Fatollahzadeh, G. Heidarinejad, H. Pasdarshahri, Investigating the effect of supply air temperature on thermal comfort and indoor air quality for a displacement ventilated room in summer, Modares Mechanical Engineering, 14(9) (2014) 35–44.
[7] A. Zolfaghari, A. Foadaddini, M. Hooshmand, Performance analysis of a task/ambient air conditioning system for providing the thermal comfort condition during sleep, Modares Mechanical Engineering, 15(10) (2015) 302–310.
[8] M.N. Bahadori, Natural air-conditioning systems, Advanced in solar energy, 3(5) (1986) 283–356.
[9] S.H. Ho, L. Rosario, M.M. Rahman, Thermal comfort enhancement by using a ceiling fan, Applied Thermal Engineering, 29, (2009) 1648–1656.
[10] R. Bassiouny, N.S. Korah, Studying the features of air flow induced by a room ceiling-fan, Energy and Buildings, 43 (2011) 1913–1918.
[11] S. Petersen, N.U. Christensen, C. Heinsen, A.S. Hansen, Investigation of the displacement effect of a diffuse ceiling ventilation system, Energy and Buildings, 85 (2014) 265–274.
[12] M. Khalili Azad, A. Omidvar, Numerical Study of Ceiling Utilization Effect on Energy Usage Amount and Residual Thermal Comfort in Cold Season, The Caspian Sea Journal, 10(1) (2016) 179–186.
[13] J. J. Faraji, Influence of Ceiling fans on Space Heating, International Journal of Current Engineering and Technology, 6(2) (2016) 612–616.
[14] F. C. McQuiston, J.D. Parker, J.D. Spilter, Heating, Ventilating, Air Conditioning Analyzing and Design, Wiley & Sons, Newyork, 2000.
[15] M. Moaref, S.A.R. Zolfaghari, A. Omidvar, Proper design of the facade and the outer shell of the building is an effective way to prevent the occurrence of condensation in the cooling system, radiant ceiling, Iranian Journal of Energy, 10(26) (2006) 3–18.
[16] Meteorological Organization I.R. Of Iran, http://www.irimo.ir.
[17] C. H. Hansen C. H. Sehrndt, Fundamentals of acoustics, Fundemental of Acoustics, Prevention and Control. World Health Organization, 2001.
[18] B. Farhanieh, S. Sattari, Simulation of energy saving in Iranian buildings using integrative modeling for insulation, Renewable Energy, 31 (2006) 417–425.
[19] F. Garoosi, F. Hoseininejad, Numerical study of natural and mixed convection heat transfer between differentially heated cylinders in an adiabatic enclosure filled with nanofluid, Journal of Molecular Liquids, 215 (2016) 1–17.
[20] T. Haraa, Sh. Kato, Numerical simulation of thermal plumes in free space using the standard k-ε model, Fire Safety Journal, 39 (2004) 105–129.
[21] F. Ampofo, T.G. Karayiannis, Experimental bench mark data for turbulent natural convection in an air filled square cavity, International Journal of Heat and Mass Transfer, 46 (2003) 3551–3572.
[22] A.K. Sharma, K. Velusamy, C. Balaji, Turbulent natural convection in an enclosure with localized heating from below, International Journal of Thermal Sciences, 46 (2007) 1232–1241.
[23] A. Jain, R. R. Upadhyay, S. Chandra, M. Saini, S. Kale, Experimental investigation of the flow field of a ceiling fan, In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference, 93–99, 2004.
[24] Sh. Heidari, “Comparative analysis between air movement, air temperature and comfort case study: hot and dry region of Iran”. Journal of fine arts, 17(2) (2013) 37–42.
[25] P. O. Fanger, What is IAQ?, Indoor Air, 16(5) (2006) 328–334.
[26] ASHRAE Handbook Fundamentals, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, 2005.
Amirkabir Journal of Mechanical Engineering
Volume 50, Issue 2
July and August 2018
Pages 309-326

Files

Share

How to cite

Statistics