Computer Aided Sustainable Design

One of the most important aspects architects need to consider fairly early on is that of energy saving, cost, thermal comfort and the effect on the environment in terms of CO2 emissions. At present, during the early design stage of a building, different options are assessed using simple tools (tables, graphs and software) that contain a large number of assumptions the very nature of which can bias choice or possibly lead to an inappropriate solution. It can be argued that the only way to provide a rational assessment of options is to use calculation methods that represent in detail the physical processes involved, this usually involves the use of dynamic thermal models. Furthermore if this tool is also used during detailed design it would introduce a consistency that is normally absent from the analytical design process. Many designers are of the opinion that, because not all details are known, then such tools are not suitable for application at early stages in the design. This view can be challenged because, even at the concept stage, a great deal is known about a building. This paper aims to show that a general description of a building can be used to generate sufficient data to drive a valid analysis using a detailed thermal model at the early sketch stage of the design process. The paper describes the philosophy, methodology and the interface developed to achieve this aim. The interface guides the user through the input process using a series of screens giving options for keywords used to describe the building, comprehensive default data built into the software are then attached to these keywords. The resulting data file is a building description that is the best possible interpretation of the design intent. This can then be used to assess options and guide towards a final design.