ABSTRACT
There is an obvious and indisputable need for an increase in the efficiency of energy utilisation in buildings. Calculations in energy simulations and analyses of energy flows in buildings have commonly been based on the energy conservation principle, the first law of thermodynamics. A more holistic view in these calculations is gained by estimating the primary energy demand for all processes. As shown in the paper, the energy conservation concept alone is not adequate in gaining a full understanding of all the important aspects of energy utilisation processes. Thus, a method for exergy analyses based on a combination of the first and second laws of thermodynamics, is presented for a better understanding and design of energy flows in buildings. In order to achieve an exergy optimised building design, loads on the building service system have to be reduced as much as possible. Generally, first priority should be given to creating an energy efficient building shell. Then, improvements to the building service system, will be much more efficient. This paper summarises the international collaboration work of the recently finished IEA ECBCS Annex 37 and the work of the International Society for Low Exergy Systems in Buildings (LowExNet).
