Exergy analysis applied to building design

Exergy analysis offers the potential of minimizing energy resource depletion, and is useful for assisting building designers in choosing building and building service concepts. Exergy recognizes that the energy that is carried by substances can only be used 'down' to the level that is given by the environment. Unlike energy, exergy is not subject to a conservation law. This paper presents an outline of an exergy analysis tool for buildings and building services, including a new graphic input interface being developed with the aim of enhancing its user-friendliness. The idea underlying this interface is that energy engineers and building designers may approach the same contents from different perspectives. The tool illustrates energy and exergy flows in a building, including energy conversion steps in the building and building services, and exergy dissipation via the building envelope as a result of heat transmission and ventilation. The main advantage of this tool is that it enables a designer to compare energy and exergy flows for different building and building service configurations, from primary energy conversion through to the heating system and building envelope.