Title: Functional exergy efficiency and exergy consumption behaviour for air-to-air heat exchangers operating at near-environmental temperatures

Authors: E.C. Boelman, P. Sakulpipatsin, H.J. Van Der Kooi, L.C.M. Itard, P.G. Luscuere

Addresses: Faculty of Architecture, Building Technology Section, Delft University of Technology, 2628 CR Delft, Berlageweg 1, The Netherlands. ' Faculty of Architecture, Building Technology Section, Delft University of Technology, 2628 CR Delft, Berlageweg 1, The Netherlands. ' Faculty of Architecture, Building Technology Section, Delft University of Technology, 2628 CR Delft, Berlageweg 1, The Netherlands. ' OTB Research Institute for Housing, Urban and Mobility Studies, Delft University of Technology, P.O. Box 5030, 2600 GA Delft, The Netherlands. ' Faculty of Architecture, Building Technology Section, Delft University of Technology, 2628 CR Delft, Berlageweg 1, The Netherlands

Abstract: This paper investigates how temperature changes affect the efficiency of thermal exergy transfer at near-environmental temperatures. Depending on the combinations of heat exchanger and environmental temperatures, different values of functional exergy efficiency can be obtained for the same heat transfer effectiveness. Some temperature combinations can lead to unexpected values of functional exergy efficiency. A dimensionless temperature T′ is proposed to identify and analyse patterns in the temperature sensitivity of functional exergy efficiency. T′ is combined with the notion of warm and cool exergy to explain the results, and to identify exergy-efficient temperature combinations for heat exchange at near-environmental temperatures.

Keywords: functional exergy efficiency; heat exchangers; space heating; HVAC design; exergy consumption behaviour; temperature changes.

DOI: 10.1504/IJEX.2008.020827

International Journal of Exergy, 2008 Vol.5 No.5/6, pp.582 - 604

Published online: 17 Oct 2008 *

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