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