Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration

Liquid desiccant dehumidification system has gained much progress recently for its considerable energy saving potential without liquid water condensation. Within the system, regeneration is of great importance since diluted desiccant solution after dehumidification needs to be re-concentrated. The o...

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Main Authors: Bai, Hongyu, Zhu, Jie, Chen, Ziwei, Chu, Junze, Liu, Yiwen
Format: Article
Published: Elsevier 2018
Subjects:
Online Access:https://eprints.nottingham.ac.uk/51633/
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author Bai, Hongyu
Zhu, Jie
Chen, Ziwei
Chu, Junze
Liu, Yiwen
author_facet Bai, Hongyu
Zhu, Jie
Chen, Ziwei
Chu, Junze
Liu, Yiwen
author_sort Bai, Hongyu
building Nottingham Research Data Repository
collection Online Access
description Liquid desiccant dehumidification system has gained much progress recently for its considerable energy saving potential without liquid water condensation. Within the system, regeneration is of great importance since diluted desiccant solution after dehumidification needs to be re-concentrated. The operational characteristics of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration are investigated in this study. The liquid desiccant and air are in a cross-flow arrangement, and separated by semi-permeable membranes to avoid carry-over problem. The regeneration performance is examined by numerical simulation and experimental test. Solution side effectiveness, temperature decrease rate (TDR) and moisture flux rate (MFR) are applied to evaluate heat and mass transfer in the regenerator. Effects of main operating parameters are assessed, which include dimensionless parameters (i.e. number of heat transfer units NTU and solution to air mass flow rate ratio m∗), solution inlet properties (i.e. temperature T sol,in and concentration C sol,in) and air inlet conditions (i.e. temperature T air,in and humidity ratio air,in). It is found that m∗ and NTU are two of the most important parameters and their effects on the regeneration performance are interacted with each other. There is hardly benefit to the performance improvement by increasing NTU at low m∗ or increasing m∗ at low NTU. Even though the regeneration performance can be improved by increasing m∗ and NTU, its improvement gradient is limited when m∗ and NTU exceed 2 and 4 respectively. It is also found that increasing olution inlet temperature is an effective approach to enhance the regeneration performance, while air inlet temperature and humidity ratio have negligible effects on it.
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spelling nottingham-516332020-05-04T19:44:56Z https://eprints.nottingham.ac.uk/51633/ Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration Bai, Hongyu Zhu, Jie Chen, Ziwei Chu, Junze Liu, Yiwen Liquid desiccant dehumidification system has gained much progress recently for its considerable energy saving potential without liquid water condensation. Within the system, regeneration is of great importance since diluted desiccant solution after dehumidification needs to be re-concentrated. The operational characteristics of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration are investigated in this study. The liquid desiccant and air are in a cross-flow arrangement, and separated by semi-permeable membranes to avoid carry-over problem. The regeneration performance is examined by numerical simulation and experimental test. Solution side effectiveness, temperature decrease rate (TDR) and moisture flux rate (MFR) are applied to evaluate heat and mass transfer in the regenerator. Effects of main operating parameters are assessed, which include dimensionless parameters (i.e. number of heat transfer units NTU and solution to air mass flow rate ratio m∗), solution inlet properties (i.e. temperature T sol,in and concentration C sol,in) and air inlet conditions (i.e. temperature T air,in and humidity ratio air,in). It is found that m∗ and NTU are two of the most important parameters and their effects on the regeneration performance are interacted with each other. There is hardly benefit to the performance improvement by increasing NTU at low m∗ or increasing m∗ at low NTU. Even though the regeneration performance can be improved by increasing m∗ and NTU, its improvement gradient is limited when m∗ and NTU exceed 2 and 4 respectively. It is also found that increasing olution inlet temperature is an effective approach to enhance the regeneration performance, while air inlet temperature and humidity ratio have negligible effects on it. Elsevier 2018-07-05 Article PeerReviewed Bai, Hongyu, Zhu, Jie, Chen, Ziwei, Chu, Junze and Liu, Yiwen (2018) Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration. Applied Thermal Engineering, 139 . pp. 569-584. ISSN 1873-5606 liquid desiccant regeneration numerical modelling membrane-based flat-plate exchange https://www.sciencedirect.com/science/article/pii/S1359431118315424?via%3Dihub doi:10.1016/j.applthermaleng.2018.05.011 doi:10.1016/j.applthermaleng.2018.05.011
spellingShingle liquid desiccant
regeneration
numerical modelling
membrane-based flat-plate exchange
Bai, Hongyu
Zhu, Jie
Chen, Ziwei
Chu, Junze
Liu, Yiwen
Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration
title Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration
title_full Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration
title_fullStr Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration
title_full_unstemmed Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration
title_short Performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration
title_sort performance evaluation of a membrane-based flat-plate heat and mass exchanger used for liquid desiccant regeneration
topic liquid desiccant
regeneration
numerical modelling
membrane-based flat-plate exchange
url https://eprints.nottingham.ac.uk/51633/
https://eprints.nottingham.ac.uk/51633/
https://eprints.nottingham.ac.uk/51633/