|Design Handbook on Passive Solar Heating and Natural Cooling (HABITAT, 1990, 162 p.)|
The design process is a complex. deliberate set of acts In which the designer aims to bring together, as a whole, a balance of all aspects of the problem to produce a solution. The climate, the energy use and the thermal comfort needs of the end-user are Just some of the inputs to the process. The focus of this publication is specifically on these aspects whilst still considering the other aspects of the whole such as shelter, durability, and appropriateness. The most important goal must be to aim for a balance of all these as good architecture is the product of such a balance.
The use of the sun and climate for thermal comfort and energy efficiency is as important a part of the whole design as is the structural design or indeed the design of the spaces themselves.
Some aspects of thermal design are both very simple and fundamental to a successful solution, others are more complex and require detailed calculation to fine-tune them and produce the most economically efficient result. In many instances where the building is a "one-off" design, the refinement of the building economics may be less important than, say. the method of construction for an owner-built design or the visual finishes of a prestige building. In such cases it is often not necessary to refine the thermal design thoroughly with extensive and detailed calculation.
In cases where a design is to be reused many times or the building is a prototype for further development, comprehensive design analysis is most important. The savings that will accrue from the reuse of the design work will be extremely beneficial to the community involved.
Before finalizing a design brief it is important to understand the social. cultural and climatic context of the proposed building. The first two can usually be established through careful consultation with the client(s) whilst the climatic context must be established by the designer from a knowledge and/or investigation of the site.
Most of the populated areas of Australia are located in what might be called a "summer driven climate", i.e.. warmer weather occupies the major part of the year. There are a few exceptions to this: mainly Tasmania, and the high altitude country of the Australian Alps and the Southern and Northern Tablelands along the East Coast.
Whilst designing for year-round comfort it is important to pay particular attention to the design for the more dominant season. In most of the Australian domestic sector, winter space heating consumes more energy than space cooling because a relatively small percentage of homes have full air conditioning. In some of the hotter climates, however, the situation is changing. Where the summers are hot and humidity levels are low, evaporative cooling is used extensively. These units require a ready supply of clean water, but are relatively tow energy users. In the more humid hot areas reverse-cycle air conditioning is the only choice.
Electricity marketing bodies throughout Australia are promoting the use of heat pumps for space heating because their coefficient of performance (COP) makes this form of heating competitive with natural gas. However, for a small additional cost, these units can be purchased as full reverse-cycle air-conditioning units, thus providing a readily available cooling system for the summer months. This trend will help to increase the overall energy consumption (especially in summer) and raise expectations of thermal comfort. The penalty to the consumer in the short term is increased living costs. whilst to the environment the increasing demand for electricity (generated from burning coal) will only serve to accelerate the growing problems of the global greenhouse effect.
The integration of good thermal design into the whole design process is only possible if it is started at the beginning of the design process. Like the integration of structure into a design, it is rarely successful if applied after the event. At each stage of the design process there are appropriate considerations that must be taken and tests applied.