Building Envelopes with Controlled Thermal Resistance
Proceedings of the 2008 World Sustainable Building Conference "World SB08" 2008
Anatolijs Borodiņecs, Uģis Bratuškins, Andris Krēsliņš, Uldis Pelīte

Traditionally low energy buildings are supposed to have maximally big thermal resistance of building envelope. In reality big thermal resistance is justified only in coldest winter days in countries with cold climate or in hot summer days with intensive solar radiation. In other periods buildings with full air conditioning would have to have different properties of building envelope that could allow heat flow in one or another direction. There are also periods when minimal resistance to vapour transfer is required. Sometimes the building envelope is needed only to prevent from rain, insects or to give the intimacy and it is not needed from the point of energy efficiency, as it does not have to form the shield against the heat or vapour flow. Building energy performance simulation models during the whole year allow choosing optimal characteristics of building envelope on the basis of annual heat consumption. The model described in this paper would help to optimise building energy performance on the condition that we can change the properties of building envelope. The paper is devoted to the analysis of possibility for construction of low energy buildings with envelopes controlled for minimization of energy consumption by air conditioning systems. It describes the possibilities to reduce energy consumption of large public buildings mainly in summer time when there are the highest electricity demands for cooling. Energy consumption depends on parameters of outdoor and indoor air, energy performance of the envelope and inside heat and moisture emissions. The paper gives a complex mathematical model for controlled envelope’s thermal resistance depending on outdoor parameters. It proposes constructive suggestion to create buildings whose walls, roofs and glassed surfaces have changeable thermal characteristics and methodology of control for separate elements (double skin facades, multiple films on windows, ventilated curtain walls, automated Venetian blinds). The paper analyses the impact of building envelope thermodynamic characteristics on the parameters of supply air in air conditioning systems. It describes the change modes of thermal resistance, resistance to water vapour transfer and resistance to solar radiation considering the different states of inside and outside air conditions. As the result the paper gives theoretical algorithm of regulation of building envelope thermodynamic characteristics in ideal conditions based on minimization of energy use by air conditioning systems.


Atslēgas vārdi
controlled thermal resistance, energy performance, low energy buildings

Borodiņecs, A., Bratuškins, U., Krēsliņš, A., Pelīte, U. Building Envelopes with Controlled Thermal Resistance. No: Proceedings of the 2008 World Sustainable Building Conference "World SB08", Austrālija, Melbourne, 21.-25. septembris, 2008. Balnarring: ASN Events Pty, 2008, 2855.-2860.lpp. ISBN 9780646503721.

Publikācijas valoda
English (en)
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