Cover Image
close this bookDesign Handbook on Passive Solar Heating and Natural Cooling (HABITAT, 1990, 162 p.)
View the document(introduction...)
View the documentForeword
close this folderIntroduction
View the documentA. The design process
View the documentB. Site investigation
View the documentC. Relating the brief to the site
View the documentD. Schematic design stage
View the documentE. Detailed design stage
View the documentF. An outline to this publication
close this folderI. Principles of passive solar architecture
View the document(introduction...)
View the documentA. Site planning and orientation
View the documentB. Importance of heat storage
View the documentC. Using earth to save energy
View the documentD. Energy losses through draughts
close this folderII. The Australian climates and people
View the documentA. The population
View the documentB. Climatic influences and lifestyles
close this folderIII. Fundamentals of heat flow
View the documentA. Simple heat flow
View the documentB. The conductivity of different materials in groups
View the documentC. Thermal resistance
View the documentD. Surface resistance
View the documentE. Cavity resistances
View the documentF. Thermal transmittance
close this folderIV. Thermal comfort
View the document(introduction...)
View the documentA. Variables influencing comfort
View the documentB. Environmental comfort
close this folderV. Basic design principles and strategies
View the documentA. Climates
View the documentB. The sun's movement
View the documentC. Orientation for solar access
View the documentD. What is solar access?
View the documentE. Solar energy collection
View the documentF. Energy storage (heat)
View the documentG. Heat retention
View the documentH. Heat distribution
View the documentI. Passive solar heating strategies
View the documentJ. Natural cooling strategies
close this folderVI. Bio-climatic analysis and comfort strategies
View the documentA. Climatic factors
View the documentB. Bioclimatic design strategies
close this folderVII. Detail design
View the documentA. General
View the documentB. Solar access, shading and window protection
View the documentC. Control of conductive heat flow
View the documentD. Evaluation of internal heat loads
View the documentE. Cross-ventilation and air flow
View the documentF. Glass-mass relationship
View the documentG. Air infiltration
close this folderVIII. Final design evaluation
View the document(introduction...)
View the documentA. Steady-state evaluation
View the documentB. 5-star design rating system a correlation technique
View the documentC. Monthly mean indoor temperature
View the documentD. CHEETAH - Thermal behaviour and energy load simulation model
View the documentAnnex I: Relevant Australian standards
View the documentAnnex II: Glossary of terms
View the documentAnnex III: Metric units of measurements
View the documentAnnex IV: Typical internal heat loads for appliances
View the documentAnnex V: Minimum additional thermal resistance requirements
View the documentAnnex VI: Climate data for Sydney region - mean daily insolation for Sydney
View the documentAnnex VII: Selected thermal properties of various building material
View the documentAnnex VIII: Selected u-values and r-values
View the documentAnnex IX: Heating degree day data - new south Wales
View the documentAnnex X: Glass-mass performance graphs
View the documentAnnex XI: Appraisal graphs for the 5-star design rating system
View the documentAnnex XII: Sun position charts for Australian capital cities
View the documentAnnex XIII: Bibliography and suggested reading

A. General

The detail design for passive solar heating and natural cooling involves the careful checking and selection of the various elements of the building. Some design issues are important to both passive solar heating and natural cooling principles such as the control of conductive heat flow (control of heat out in winter and in during summer) whilst the design or selection of shading is important for its summer control and important in its absence in winter to let the sun in.

It has been found in recent studies undertaken for the 5-star design rating system that thermal-storage materials inside a house influence comfort levels in both summer and winter. The mass has little effect however on the heating loads of an intermittently heated house (the more common pattern of heating in most of Australia except in the very cold areas).

1. Passive solar heating

In both the cool-temperate and the hot-arid zones, passive solar heating is necessary in winter. The detailed design procedure should be as follows:

(a) Locate as many habitable rooms as possible with a northerly outlook to receive winter sun and buffer spaces to the south as natural insulation to habitable rooms. Provide adequate air-lock protection to main entrances for draft control;

(b) Determine the desirable glass-mass relationship for specific location and building use;

(c) Select or adapt the desired construction system to achieve the appropriate glass-mass relationship;

(d) Develop construction details to facilitate the economic installation of appropriate insulation levels in all external fabric;

(e) Select and specify glazing and window treatments for optimum daytime solar gains and minimum conductive losses:

(f) Develop construction details to minimize heat loss due to infiltration.

2. Natural cooling and summer comfort

In much of the year overheating inside buildings is the result of excess solar heating and internally generated heat reaching the interior spaces. This is certainly the case where the ambient air temperatures are no greater than about 27C. In such cases it is usually practicable to maintain comfort conditions with appropriate control of those heat gains (such as shading of windows and exhausting internal heat) and good ventilation and air movement patterns.

Where air temperatures are above reasonable comfort levels it is necessary to apply other strategies that will collect or soak up the excess heat for disposal into the cooler earth or to the cooler night air. In these cases the design approach should be as follows:

(a) Reduce solar gains to the interior by correctly designed shading;

(b) Minimize conductive gains by shading wall and other surfaces as appropriate and insulating the external fabric of the building;

(c) Minimize the effects of internal gains (lights and other appliances) by exhausting the heat:

(d) Design night ventilation openings to optimize the cooling of thermal sinks (thermal mass):

(e) Allow for appropriate air movement (ceiling fans and the like) to raise the occupants' comfort threshold;

(f) Design for minimum air infiltration during the day when external air is 3 deg.C greater than the upper comfort limit.

The overall goal is to be warm in winter and cool in summer. The sections that follow will assist the designer to achieve these goals by design, not by accident.