Title: The impact of water flow configuration on crystallisation in LiBr/H2O absorption water heater

Authors: Kai Wang, Omar Abdelaziz, Edward A. Vineyard

Addresses: Building Equipment Research Group, Energy and Transportation Science Division, Oak Ridge National Laboratory, P.O. Box 2008, MS-6070, One Bethel Valley Road, Oak Ridge, TN 37831-6070, USA. ' Building Equipment Research Group, Energy and Transportation Science Division, Oak Ridge National Laboratory, P.O. Box 2008, MS-6070, One Bethel Valley Road, Oak Ridge, TN 37831-6070, USA. ' Building Equipment Research Group, Energy and Transportation Science Division, Oak Ridge National Laboratory, P.O. Box 2008, MS-6070, One Bethel Valley Road, Oak Ridge, TN 37831-6070, USA

Abstract: Lithium Bromide (LiBr) strong solution entering the absorber tends to crystallise when the absorber temperature is increased for a fixed evaporating pressure. This is considered the key technical barrier for the development of a LiBr absorption heat pump water heater. There are several approaches to avoid the crystallisation problem, such as chemical crystallisation inhibitors, heat and mass transfer enhancement and thermodynamic cycle modification. This paper investigates and compares two flow configurations of LiBr absorption heat pump water heater to evaluate the allowable operating conditions for each. The simulation results indicated that introducing the process water through the absorber first results in lower absorber temperature and hence less tendency for crystallisation.

Keywords: absorption heat pumps; water heaters; crystallisation; control strategy; water flow; flow configuration; lithium bromide; absorber temperature; evaporating pressure; simulation.

DOI: 10.1504/IJETP.2011.039221

International Journal of Energy Technology and Policy, 2011 Vol.7 No.4, pp.393 - 404

Published online: 28 Mar 2011 *

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