Simulation of a 3-Fluid Membrane Liquid Desiccant Air-Conditioning System
Date
2017-11-29
Authors
Journal Title
Journal ISSN
Volume Title
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ORCID
Type
Thesis
Degree Level
Masters
Abstract
A liquid-to-air membrane energy exchanger (LAMEE) is able to simultaneously cool and dehumidify air by transferring heat and moisture between the air stream and a liquid desiccant solution. The heat and moisture transfer rates in a LAMEE can be enhanced if a third fluid stream is used to control the desiccant solution temperature in the LAMEE. A LAMEE with a third fluid stream is known as a 3-fluid LAMEE. Published studies on 3-fluid LAMEEs are limited to experiments on the exchanger under limited test conditions.
This thesis focuses on simulating the performance of a 3-fluid LAMEE in a membrane liquid desiccant air-conditioning (M-LDAC) system. In the thesis, empirical correlations are developed based on experimental data to model the 3-fluid LAMEE and the limitations of the empirical model are evaluated. Subsequently, the 3-fluid and 2-fluid M-LDAC systems are simulated and compared at six different dehumidification load conditions. The simulation results show that, for most conditions, the 3-fluid M-LDAC system is able to meet the dehumidification load with a lower energy input than the 2-fluid M-LDAC system. The energy efficiency of the 2-fluid M-LDAC system is higher than the 3-fluid M-LDAC system at only the lowest dehumidification load.
The 3-fluid and 2-fluid M-LDAC systems are paired with a radiant cooling system to condition a small office building located in a hot-humid climate (Miami, Florida). Both the 2-fluid and 3-fluid systems provide acceptable thermal environment within the office building but the energy consumption of the 2-fluid system is 50% higher than the 3-fluid system. This thesis concludes that the 3-fluid M-LDAC system may be more suitable than the 2-fluid M-LDAC system for hot and humid climates and in buildings with high dehumidification loads.
Description
Keywords
Liquid-to-ar membrane energy exchanger (LAMEE), 3-fluid LAMEE, Coefficient of Performance, TRNSYS, Liquid desiccant air-conditioning, air-conditioning
Citation
Degree
Master of Science (M.Sc.)
Department
Mechanical Engineering
Program
Mechanical Engineering