ABSTRACT
Some of the earliest CAD systems to have been developed were those that focused on the specific and discrete tasks of environmental analysis in order to assess the performance of building proposals. These tasks include environmental systems such as ventilation and lighting, for example, with heating and energy systems being of particular importance. Thermal analysis ranges from simple U-value calculations, through to complex simulations that dynamically model thermal properties. Typically these methods are used to assess and compare the thermal behaviours of different types of construction based upon standard procedures, such as those developed by CIBSE (Chartered Institution of Building Services Engineers), and ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers). Material properties need to be specified by users as input data, and graphical output is often produced in the form of temperature profile graphs through the building fabric and surrounding spaces. Historically, the conventional CAD modelling of building proposals and their corresponding thermal analyses have required separate and unrelated forms of input and output, often causing a separation between architects, and specialists in services and environmental issues. The greater integration of computer software from these two areas now makes it feasible to visualise and analyse within the same computing environment.
