Year

2017

Degree Name

Doctor of Philosophy

Department

Sustainable Buildings Research Centre

Abstract

A large proportion of energy used worldwide is for building heating, cooling and dehumidification. Improvements in building energy efficiency are therefore essential to reduce global energy usage and greenhouse gas emissions. Over the last several decades, many efforts have been made on the development and application of various sustainable and low energy technologies to increase building energy efficiency. Among them, liquid desiccant dehumidification has gained significant scientific attention due to its high potential to achieve energy savings in tropical and subtropical regions.

In a liquid desiccant air conditioning (LDAC) system, the regeneration of the liquid desiccant is a key process to maintain the capacity of the liquid desiccant for continuous air dehumidification. Different regeneration methods have been studied for LDAC systems, including but not limited to thermal regeneration, ultrasonic regeneration, reverse osmosis regeneration and electrodialysis (ED) regeneration. The use of ED for liquid desiccant regeneration has only been explored recently, and the ways to integrate ED into LDAC systems and the likely benefits of using EDassisted LDAC systems have not previously been examined in depth.

The use of ED in the areas such as desalination and wastewater treatment has been extensively studied and the results indicated that the performance of an ED stack is influenced by the construction configuration and many operating parameters. As the concentration of liquid desiccants used in LDAC systems is much higher than that of the solutions used in other fields such as water desalination, the behaviour of ED working with liquid desiccants is expected to differ from that in other fields. Salt mass transfer and water mass transfer during the ED regeneration process are the key factors influencing the concentration and volume variation of the solutions in an ED stack and both are highly dependent on the operating conditions. Thus, key knowledge gaps to date include the effects of operating parameters on the regenerative ability of ED stacks for liquid desiccant regeneration, and the detailed mass transfer mechanisms and energy consumption of such ED systems under different operating conditions.

This thesis is unavailable until Wednesday, November 13, 2019

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