Low Exergy Systems for High-Performance Buildings and Communities
Abstract
As a consequence of the latest reports on climate change and the needed reduction in CO2 emissions, huge efforts must be made in the future to conserve high quality, or primary energy, resources. A new dimension will be added to this problem if countries with fast growing economies continue to increase their consumption of fossil energy sources in the same manner as they do now. Even though there is still considerable energy saving potential in the building stock, the results of the finished IEA ECBCS Annex 37, Low Exergy Systems for Heating and Cooling of Buildings (Annex 37, 2011), show that there is an equal or greater potential in exergy management (Ala-Juusela 2004). This implies working with the whole energy chain, taking into consideration the different quality levels involved, from generation to final use, in order to significantly reduce the fraction of primary or high-grade energy used and thereby minimise exergy consumption (Schmidt 2004). New advanced forms of technology need to be implemented. At the same time, as the use of high quality energy for heating and cooling is reduced, there is more reason to apply an integral approach, which includes all other processes where energy/exergy is used in buildings. In recent years, we have made substantial progress in the development of new and integrated techniques for improving energy use, such as heat pumps, co-generation, thermally activated building components, and methods for harvesting renewable energy directly from solar radiation, from the ground and various other waste heat sources (Schmidt et al 2006).