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Experimental investigation of an ammonia-water-hydrogen diffusion absorption refrigerator

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Title: Experimental investigation of an ammonia-water-hydrogen diffusion absorption refrigerator
Authors: Najjaran Kheirabadi, A
Freeman, J
Ramos Cabal, A
Markides, C
Item Type: Journal Article
Abstract: Diffusion absorption refrigeration (DAR) is a small-scale cooling technology that can be driven purely by thermal energy without the need for electrical or mechanical inputs. In this work, a detailed experimental evaluation was undertaken of a newly-proposed DAR unit with a nominal cooling capacity of 100~W, aimed at solar-driven cooling applications in warm climates. Electrical cartridge heaters were used to provide the thermal input which was varied in the range 150-700 W, resulting in heat source temperatures of 175--215 C measured at the generator. The cooling output during steady-state operation was determined from the power consumed by an electric heater used to maintain constant air temperature in an insulated box constructed around the evaporator. Tests were performed with the DAR system configured with the default manufacturer's settings (22 bar charge pressure and 30 % ammonia concentration). The measured cooling output (to air) across the range of generator heat inputs was 24--108 W, while the coefficient of performance (COP) range was 0.11--0.26. The maximum COP was obtained at a generator heat input of 300 W. Results were compared to performance predictions from a steady-state thermodynamic model of the DAR cycle, showing a reasonable level of agreement at the nominal design point of system, but noteworthy deviations at part-load/off-design conditions. Temperature measurements from the experimental apparatus were used to evaluate assumptions used in the estimation of the model state point parameters and examine their influence on the predicted system performance.
Issue Date: 15-Dec-2019
Date of Acceptance: 8-Sep-2019
URI: http://hdl.handle.net/10044/1/73355
DOI: 10.1016/j.apenergy.2019.113899
ISSN: 0306-2619
Publisher: Elsevier
Journal / Book Title: Applied Energy
Volume: 256
Copyright Statement: © 2019 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Funder's Grant Number: EP/P030920/1
Keywords: Science & Technology
Energy & Fuels
Engineering, Chemical
Diffusion absorption refrigeration
Absorption cooling
Coefficient of performance
Part-load operation
09 Engineering
14 Economics
Publication Status: Published
Article Number: ARTN 113899
Online Publication Date: 2019-10-05
Appears in Collections:Chemical Engineering
Faculty of Engineering

This item is licensed under a Creative Commons License Creative Commons