Low Exergy Systems for High-Performance Buildings and Communities

There is an obvious and indisputable need for anincrease in the efficiency of energy utilization inbuildings. Heating, cooling and lightingappliances in buildings account for more thanone third of the world's primary energy demand.In turn, building stock is a major contributor toenergy-related environmental problems. Thereare great potentials, which can be obtainedthrough a niore efficient use of energy inbuildings.A careful look at the exergy flows inbuildings and the related supply structures,similar to other thermodynamic systems such aspower stations, can help identify the potential ofincreased efficiency in energy utilization.Through the analyses, it can be shown thatcalculations based on the energy conservationand primary energy concept alone areinadequate for gaining a full understanding ofall important aspects of energy utilizationprocesses. For example, the high potential for afurther increase in the efficiency of boilerswhose energy efficiency is close to loo%, cannot be quantified by energy analysis alone, butit can be shown by using exergy analysis(Schmidt and Shukuya 2003), the exergyefficiency of a common gas boiler is about 8%.This paper outlines the internationalco-operative work in the general framework ofthe International Energy Agency EnergyConservation in Buildings and CommunitiesSystems (TEA ECBCS), the: Annex 49 "LowExergy Systems for High PerformanceBuildings and Coniniunities" (Annex 49 2007).