Enhancemet and analysis of a hybrid liquid desiccant based-cooling system

Air conditioning has traditionally been achieved by vapour compression equipment, which is considered very efficient when handling loads characterised by high sensible load fraction. These machines would perform poorly when they process air with high latent load fraction as in the case of humid clim...

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Main Author:	Mahgoub, Elhadi Badawi
Format:	Thesis
Language:	English
Published:	2007
Subjects:	TJ Mechanical engineering and machinery
Online Access:	http://eprints.utm.my/id/eprint/18680/1/ElhadiBadawiMahgoubPFKM2007.pdf
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id	my-utm-ep.18680
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spelling	my-utm-ep.186802017-10-12T05:08:58Z Enhancemet and analysis of a hybrid liquid desiccant based-cooling system 2007-07 Mahgoub, Elhadi Badawi TJ Mechanical engineering and machinery Air conditioning has traditionally been achieved by vapour compression equipment, which is considered very efficient when handling loads characterised by high sensible load fraction. These machines would perform poorly when they process air with high latent load fraction as in the case of humid climates. Global energy concern has accelerated the research on alternative technology options to replace traditional method or improve their performance. Hybrid liquid desiccant system has been proposed as an energy saving alternative to reduce the vapour compression unit size used in air conditioning application, and improve its performance. A hybrid system consisting of vapour compression unit, a liquid desiccant system consisting of an absorber and a regenerator, both of which are identical packed spray towers built from fibre glass with a cross sectional area of 600 x 600 mm from five pieces each. Each piece having a height of 200 mm to facilitate testing different heights of packing material, and a flat plate solar hot water collector with an auxiliary electrical heater to be used as supplement when solar energy is not enough or not available. This hybrid system was designed, fabricated and tested with emphasis on liquid desiccant sub-system. In this study, the performance of the absorber and the regenerator, which are the main items in the liquid desiccant system, was studied in terms of effectiveness. Both units were tested over a range of different inlet liquid desiccant concentration of 20% to 40% by weight, and inlet temperature of 20oC, 25oC, and 30oC for the absorber, and 20%, 25% and 30% liquid desiccant concentration at temperature range of 35oC to 55oC for the regenerator. Both components were tested at liquid desiccant flow rate between 3.76 to 5.01 l/min with different air inlet flow rate 4.9 to 6.4 m3/min. Experimental results were recorded using a complete data acquisition system to collect and log the data of the desiccant sub-system and the vapour compression unit, which enables thermocouples readings. From the data collected, the coefficient of performance of the vapour compression unit was obtained using both refrigerant enthalpy and air enthalpy methods. Absorber effectiveness was found to be between 0.5 and 0.7, while the regenerator effectiveness was found to be between 0.2 and 0.6. A 800 mm packing height is found to be the breaking limit with both air supply either fully through the desiccant or partly (50% through the desiccant), would result in an improvement in the performance of the vapour compression unit ranging from 17.9 % to 54%, which indicate the hybrid system potential for energy savings. Improving indoor air quality by controlling humidity, killing effect of bacteria and fungus by using liquid desiccant are among other benefits realised. 2007-07 Thesis http://eprints.utm.my/id/eprint/18680/ http://eprints.utm.my/id/eprint/18680/1/ElhadiBadawiMahgoubPFKM2007.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:62490?queryType=vitalDismax&query=+Enhancemet+and+analysis+of+a+hybrid+liquid+desiccant+based-cooling+system+&public=true phd doctoral Universiti Teknologi Malaysia, Fakulti Kejuruteraan Mekanikal Fakulti Kejuruteraan Mekanikal
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TJ Mechanical engineering and machinery
spellingShingle	TJ Mechanical engineering and machinery Mahgoub, Elhadi Badawi Enhancemet and analysis of a hybrid liquid desiccant based-cooling system
description	Air conditioning has traditionally been achieved by vapour compression equipment, which is considered very efficient when handling loads characterised by high sensible load fraction. These machines would perform poorly when they process air with high latent load fraction as in the case of humid climates. Global energy concern has accelerated the research on alternative technology options to replace traditional method or improve their performance. Hybrid liquid desiccant system has been proposed as an energy saving alternative to reduce the vapour compression unit size used in air conditioning application, and improve its performance. A hybrid system consisting of vapour compression unit, a liquid desiccant system consisting of an absorber and a regenerator, both of which are identical packed spray towers built from fibre glass with a cross sectional area of 600 x 600 mm from five pieces each. Each piece having a height of 200 mm to facilitate testing different heights of packing material, and a flat plate solar hot water collector with an auxiliary electrical heater to be used as supplement when solar energy is not enough or not available. This hybrid system was designed, fabricated and tested with emphasis on liquid desiccant sub-system. In this study, the performance of the absorber and the regenerator, which are the main items in the liquid desiccant system, was studied in terms of effectiveness. Both units were tested over a range of different inlet liquid desiccant concentration of 20% to 40% by weight, and inlet temperature of 20oC, 25oC, and 30oC for the absorber, and 20%, 25% and 30% liquid desiccant concentration at temperature range of 35oC to 55oC for the regenerator. Both components were tested at liquid desiccant flow rate between 3.76 to 5.01 l/min with different air inlet flow rate 4.9 to 6.4 m3/min. Experimental results were recorded using a complete data acquisition system to collect and log the data of the desiccant sub-system and the vapour compression unit, which enables thermocouples readings. From the data collected, the coefficient of performance of the vapour compression unit was obtained using both refrigerant enthalpy and air enthalpy methods. Absorber effectiveness was found to be between 0.5 and 0.7, while the regenerator effectiveness was found to be between 0.2 and 0.6. A 800 mm packing height is found to be the breaking limit with both air supply either fully through the desiccant or partly (50% through the desiccant), would result in an improvement in the performance of the vapour compression unit ranging from 17.9 % to 54%, which indicate the hybrid system potential for energy savings. Improving indoor air quality by controlling humidity, killing effect of bacteria and fungus by using liquid desiccant are among other benefits realised.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Mahgoub, Elhadi Badawi
author_facet	Mahgoub, Elhadi Badawi
author_sort	Mahgoub, Elhadi Badawi
title	Enhancemet and analysis of a hybrid liquid desiccant based-cooling system
title_short	Enhancemet and analysis of a hybrid liquid desiccant based-cooling system
title_full	Enhancemet and analysis of a hybrid liquid desiccant based-cooling system
title_fullStr	Enhancemet and analysis of a hybrid liquid desiccant based-cooling system
title_full_unstemmed	Enhancemet and analysis of a hybrid liquid desiccant based-cooling system
title_sort	enhancemet and analysis of a hybrid liquid desiccant based-cooling system
granting_institution	Universiti Teknologi Malaysia, Fakulti Kejuruteraan Mekanikal
granting_department	Fakulti Kejuruteraan Mekanikal
publishDate	2007
url	http://eprints.utm.my/id/eprint/18680/1/ElhadiBadawiMahgoubPFKM2007.pdf
_version_	1747815332325621760

Enhancemet and analysis of a hybrid liquid desiccant based-cooling system

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