Study on heat transfer coefficient of plastic plate heat exchanger for liquid desiccant air-conditioning application

• Main Author: Oh, Chia Wee
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Mechanical engineering::Alternative, renewable energy sources
• Online Access: http://hdl.handle.net/10356/60945
• Institution: Nanyang Technological University

Operating air conditioning equipment with low cost and high efficiency is a great challenge in the HVAC industry. Air conditioning accounts for approximately 50% of the power consumption of most buildings. Singapore being a highly urbanized city, air conditioning is widely used throughout the entire island. Together with the hot and humid climate, air conditioning has become a norm. A typical air conditioner usually performs additional cooling to meet the air humidity requirements for thermal comfort. This type of air conditioning is less efficient because they require more energy to remove water vapour from the moisture-rich air. As such, one of the major loads of the air conditioning is to perform dehumidification on the outdoor air. Any opportunity to reduce the energy usage should be looked into. A promising alternative is the use of an open absorption system such as a liquid desiccant air-conditioning system (LDAC).This system performs dehumidification by absorbing the moisture content of surrounding air using liquid desiccant. Using this technology, energy consumption for cooling can be reduced by up to 50% as the air becomes drier. By implementing this system, the amount of electricity consumed can be reduced significantly, thereby also resulting in lower greenhouse gases emissions. In this study, the process of LDAC is being investigated using a plastic heat exchanger. A thin polypropylene membrane is also used to model the process. Instead of using the liquid desiccant as the medium fluid, distilled water is used. Experimental runs were performed with varying temperatures, water flow rates etc. The results of the experiments show promising heat transfer and dehumidification or present some findings that would provide groundwork for the next phase of the LDAC research.