Paper 1: Volume 5 No.1 June 2006 Edition
Indoor Wind Speed Coefficients for Estimating Summer Comfort
Richard Aynsley
Director Research &
Development
Big Ass Fan Company,
800 Winchester Road
,
Lexington
,
KY
40505
USA
Abstract
There is a wide range of factors that influence natural ventilation. The
uncertainties arising from the unpredictable nature of wind lead to the
need to account for periods of time when winds are unable to provide
indoor summer comfort. Some methods for estimating natural ventilation are
outlined together with the effects of high site coverage, building
porosity, insect screens, and local wind shelter from adjacent houses and
vegetation. Indoor wind speed coefficients provide a direct method for
comparing the natural ventilation potential of housing stock. Adaptive
thermal comfort establishes the monthly temperature for operative comfort
and comfort zone to accommodate 80% of people. Houses in the tropical city
of
Townsville
in
Australia
are used to examine the potential for indoor summer thermal comfort.
Ceiling fans can provide an energy-efficient back-up source of air
movement for indoor comfort when winds are inadequate. The poor potential
for natural ventilation of most contemporary housing stock with high
site-coverage, raises concern for its long-term sustainability.
Key words: wind
speed coefficients,
natural ventilation,
comfort, ceiling fans, housing.
References
ASHRAE: (2004) “ANSI/ASHRAE
Standard 55-2004 Thermal Environmental Conditions for Human Occupancy”.
ASHRAE,
Atlanta
,
GA.
ASHRAE: (2005) “Handbook of
Fundamentals”, Chapter 8,
Atlanta
GA. ASHRAE.
Aynsley R: (1988) “A Resistance Approach to Estimating Natural
Ventilation in Buildings”, ASHRAE
Transactions, 94, Part 2, pp1661-1669.
Aynsley R and Spruill M: (1990) “Thermal comfort models for outdoor
thermal comfort in warm humid climates and probabilities of low wind
speeds”, Journal of Wind
Engineering and Industrial Aerodynamics, 36, pp481-488.
Aynsley R, Melbourne W and Vickery B: (1997) Architectural Aerodynamics, Applied Science,
London
, 256 pages.
Aynsley RM: (1996) “Estimating Potential for
Indoor Thermal Comfort from Natural Ventilation”, Proceedings of ROOMVENT'96
the 5th International Conference on Air Distribution in Rooms,
Yokohama
, Japan, July 17-19. 3, pp291-298.
Aynsley RM: (1997) “Diurnal variation in summer natural ventilation
potential for thermal comfort in Townsville”, Proceedings of the Fourth Asia-Pacific Symposium on Wind Engineering,
Gold Coast
,
Australia
14-16 July, pp10.
Aynsley R and Lee S: (1998) “Average versus simultaneous climatic data
for estimates of natural ventilation cooling potential”, Proceedings of ROOMVENT’98,
Stockholm
15-17 June, 2, pp401-408.
Aynsley R and Potangaroa R: (1998) “Natural ventilation: dealing with
the unpredictable”, Proceedings of
the ANZAScA ‘98 Conference,
Wellington
, 15-17 July, pp171-178.
Aynsley R: (1999) “Unresolved issues in natural ventilation for
thermal comfort”, Proceedings of
HybVent Forum ‘99, First International One-day Forum on Natural and
Hybrid Ventilation, University of Sydney, 28 Sept. pp36-44.
Aynsley R and Su B: (2003) “A Field Study of Indoor Wind Speed”, in
L.N. Lowes and G. Miller (Eds), CD
of Proceedings of the 2003 Structures Congress & Exposition, May
29-31, Seattle Washington. American Society of Civil Engineers
Conferences,
Reston
,
VA.
Daugherty RL and Franzini JB: (1977) “Fluid mechanics with engineering applications”, 7th Edition,
McGraw-Hill Kogakusha Ltd,
Tokyo
, 564p.
de Dear R and Schiller Brager G: (2001) “The adaptive model for
thermal comfort and energy conservation in the built environment”. Int.
J. Biometeorology, 45, pp100-108.
Hartman H: (1982) Mine ventilation
and air conditioning, 2nd ed.,
New York
, Wiley-Interscience. pp791.
Hennessy WB ed.: (1979) Lay course
in tropical medicine, 2nd edition, Service Publication No. 14,
Commonwealth Department of Health,
School
of
Public Health
and Tropical Medicine, The University of Sydney, 260p.
Hope P: (2003) “Energy
efficiency ratings: Implications for the building industry in the humid
tropics”. Master in Tropical Architecture dissertation,
Australian Institute of Tropical Architecture,
James
Cook
University
,
Townsville
,
Australia
, pp377.
Khedari J, Yamtraipat N, Pratintong N and Hinrunlabbh J: (2000) “
Thailand
ventilation comfort chart”. Energy
and Buildings, 32, pp245-249.
Kindangen J et al: (1997) “Effects of roofs shapes on wind induced air
motion inside buildings”. Buildings
and Environment 32 (1), pp1-11.
Lee B, Hussain M and Soliman B: (1980) “Predicting natural ventilation
forces upon low-rise buildings”. ASHRAE
Journal, February, pp35-39.
Lee S: (1998) “Natural
ventilation and medium density house forms in the tropics”.
Doctoral thesis Australian Institute of Tropical Architecture, James Cook
University, Townsville, Australia, pp. 497.
Macfarlane MV: (1958) “Thermal comfort zones”, Architectural Science Review, November, pp1-14.
Metric Handbook, 2nd ed, (1969) edited by Adler, D.
“Tropical Design”, edited by Martin Evans. Chapter 37, Table XV.
Oxford
, Architectural Press.
Murakami S, Hayashi T and Zeng Jie: (1997)
“Numerical simulation of wind environment around human body”, Proceedings
of the Fourth Asia-Pacific Symposium on Wind Engineering, 14-16 July,
Surfers Paradise, Gold Coast, Australia, pp15-18.
Shaw WN: (1907) Air currents and
the laws of ventilation.
Cambridge
,
Cambridge
University
Press.
Swami M and Chandra S: (1988) “Correlations for pressure distributions
on buildings and calculation of natural ventilation”. ASHRAE Transactions, 95, 2, pp611-620.
|
