Needs and trends in integrated building and HVAC thermal design tools

Abstract

Buildings are responsible for approximately 40% of the total energy consumption in developed countries. More than half of this is used to condition the indoor environment. Studies have shown that savings of between 30 and 70% may be realized through improved design and retrofit procedures for buildings and air conditioning equipment. Designing for energy efficiency requires a system approach that includes the building, the HVAC system and the controller. Traditional design philosophy based on load calculations is inadequate. New user-friendly design tools allowing an integrated simulation of the complete system are needed. The main features of a suitable design tool are identified. It should allow dynamic analysis of the passive performance of the building combined with pseudo-steady HVAC system simulation. HVAC component models should be based on simplified fundamental principle analysis to ensure flexibility. The tool should allow for a fully integrated simulation of the building, its HVAC system and controller. A flexible icon-based graphical interface must be complemented be expandable databases for all components to ensure user-friendly operation. The software must run on a personal computer and should also allow standard system design calculations, life-cycle cost analysis, automatic optimization features and data exchange with CAD software. No tool could be found that provided all of these needs. The use of such a tool will result in more energy-efficient solutions when designing, managing and retrofitting buildings. This will help to reduce the burden on the environment. The tool will make commissioning of new systems more precise and less laborious. The ability of the designer to guarantee desired comfort conditions will also be enhanced.