LOW EXERGY SYSTEMS FOR HIGH-PERFORMANCE BUILDINGS AND COMMUNITIES

There is an obvious and indisputable need for an increase in the efficiency of energy utilisation inbuildings. Heating, cooling and lighting appliances in buildings account for more than one third of theworlds primary energy demand. In turn, building stock is a major contributor to energy-relatedenvironmental problems. There are great potentials, which can be obtained through a more efficientuse of energy in buildings.An optimisation of the exergy flows in buildings and the related supply structures, similar to otherthermodynamic systems such as power stations, can help in identifying the potential of increasedefficiency in energy utilisation. Through analyses, it can be shown that calculations based on theenergy conservation and primary energy concept alone are inadequate for gaining a full understandingof all important aspects of energy utilisation processes. The high potential for a further increase in theefficiency of; for example, boilers, can not be quantified by energy analysis - the energy efficiency isclose to 100%; however, this potential can be showed by using exergy analysis (Schmidt and Shukuya2003), the exergy efficiency of a common gas boiler is about 8%.This paper outlines the international co-operative work in the general framework of the InternationalEnergy Agency (IEA), the ECBCS Annex 49 Low Exergy Systems for High Performance Buildings andCommunities (Annex 49 2007).