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

D. What is solar access?

Solar access can be described as allowing the sun to penetrate a building or be utilized by a solar collector on the surface of that building between 9 a.m. and 3 p.m. in midwinter. There are varying degrees of solar access. There is whole-site access where the area of yard to the north of the building, as well as the north wall and rooftop are protected from shading by other buildings and vegetation in midwinter. North-wall access refers to the protection from shadows in midwinter of only the north facade, which includes the north roof and north wall.

Although whole-site access is desirable for outdoor garden use, it can be very costly in terms of the use of land and may not affect household energy use. Energy-efficiency encompasses more than Just energy savings in houses and so the decreased density that results from whole-site access cannot be justified.

There is a third level of solar access, rooftop access, which aims to protect rooftop solar collector systems from shading at certain times. Although this level of solar access allows maximum density to be achieved, it forecloses too many options for future development. The definition of solar access depends on the definition of the solar collector (whether passive or active).


Figure 25. Heat losses from different residential building types.


Figure 26. The effect of window orientation and winter heating load.


Figure 27. Solar access in Sydney.

North-wall access is the level of access designed for in this handbook.

The protection of solar access to dwellings is crucial to the performance of passive solar architecture. The period between 9 a. m. and 3 p.m. in mid-winter, as shown in figure 27, has been generally accepted as a measure of solar access.

For mid-winter in Sydney, the azimuth of the sun is approximately 45 degrees at 9 a.m. and at 3 p.m. At noon, the altitude of the sun is approximately 30 degrees. The protection of solar access is discussed in a later chapter under detailed design guidelines.