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Department of ArchitectureThe University of Hong Kong
Building Design forCold Climates
Sam C M Hui, Mar 2001
Contents
Climate Basics
Cold Climates
Response to Climate
Human Factors
Climatic zones in the world
Cold climates Temperate climates
Hot-dry climates Warm-humid climates
Climate Classifications
Climate Basics
Cold climates lack of heat (under-heating)
Temperature climates seasonal variation between under-heating and
over-heatingHot-dry (arid) climates
overheating, dryWarm-humid climates
overheating, humid
Climate Basics
Climatic elements Temperature Humidity Air movement (wind speed and direction) Precipitation (rain, hail, snow, dew) Cloud cover Sunshine duration Solar radiation
Major climatic elements of Hong Kong
Cold Climates
Polar climates require special attentionAssume temperate climates
e.g. Canada, UK, New Zealand, Northern China Severe winters, with snow and strong icy winds
Major considerations Max. summer temperatures Min. winter temperatures Annual rainfall and humidity (dry or wet) Sky conditions (cloudy or clear)
Cold Climates
Design principles Minimal surface-to-volume ratio Insulation of all external surfaces is very important Small windows and openings, preferably double-glazed Annual solar gains through windows are generally less that
associated heat losses Use of exposed internal thermal mass Lightweight insulated structures are quick to heat up but
also quick to cool, Heavyweight structures are slow to heat up and cool down.
Cold climate (example)
- protection from wind, cold, snow drift and snow load- design for minimum heat loss
Temperature climate (example)
- protection from rain, snow, cold winds, moderate summer heat & moderate winter cold- minimize heat loss, maximize isolation in winter; consider summer shading and ventilation
Tokyo, January 1998
How could I respondto cold climate?
* Face House, Kyoto, Japan
Main criteria:• built form • orientations• wall area• window area• thermal insulation• thermal mass
Response to Climate
Climate-responsive building (Tokyo Gas Earth Port, Japan)
General climate control strategies
Response to Climate
Building envelope - outer shell of a building that determines external thermal forces exterior walls exterior windows roofs underground slab and foundation doors open to outdoor
Response to Climate
Major factors determining envelope heat flow: temperature differential, T area of exposed building surfaces, A heat transmission properties, like U-value thermal storage capacity
Effect of thermal mass delay heat transfer and store heat important for intermittently heated spaces
Response to Climate
Selection and design of window system
Activesolar
Passivesolar
{
}
Effective use of solar energy
Human Factors
Solar heatand radiation
Wind chill
Heat conductionand convection
Evaporativeheat loss
Human Factors
ASHRAE comfort envelopeThermal comfort &design conditions
Asymmetricthermal radiation
Warm orcold floor
Draft
Vertical airtemp. diff.
Local thermal discomfort
Draft - undesired localcooling of human bodycaused by air movement
Asymmetric thermal radiation in a space
Vertical air temperaturedifference - the temperaturegradient may cause localwarm discomfort at the headand/or cold discomfort at thefeet
Warm or cold floor -direct contact between thefeet and the floor causesdiscomfort; flooringmaterial is important toavoid this problem
References
Climatic Design of Buildings - An Overview http://arch.hku.hk/~cmhui/teach/65156-7.htm
Climatic Design http://fridge.arch.uwa.edu.au/topics/thermal/
climate/design.html
Climate Classification http://fridge.arch.uwa.edu.au/topics/thermal/
climate/classification.html
References
Hutcheon, N. B. and Handegord, G. O.P., 1983. Building Science for a Cold Climate, National Research Council of Canada, Toronto. [690.0911 H9]
Lstiburek, J. W., 2000. Builder’s Guide to Cold Climates: Details for Design and Construction, Taunton Press, Newtown, Conn. [693.8 L925 b]
Markus, T. A. and Morris, E. N., 1980. Buildings, Climate, and Energy, Pitman, London. [697 M34]
Watson, D. and Lab, K., 1983. Climatic Design: Energy-efficient Building Principles and Practices, McGraw-Hill, New York, 1983. [697.9 W3]