Heat and Moisture Exchangers for Energy-Efficient Buildings: Fouling, Frosting and Sorption

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Buildings are an integral part of Canadian society and economy as Canadians spend over 90% of their time in buildings. Furthermore, 30% to 50% of energy consumption is used to heat and cool buildings in Canada and other developed countries. Thus, buildings that provide Canadians with a comfortable and healthy place to work and live are essential for a healthy, prosperous and sustainable nation.*******Recent advances in energy-efficiency have reduced the amount of energy required to heat or cool buildings. Major advances have been achieved in:****(1) building envelope performance (e.g., better windows and insulation) so that less energy is needed to heat or cool buildings, and****(2) HVAC equipment efficiency (where a higher efficiency means that more heat can be added to or removed from the building with the same energy input such as electricity or natural gas).****Despite these advances, which have improved building performance and even led to buildings that produce as much energy as they consume over a certain period (called “net-zero energy buildings”), relatively little work has been done on the moisture transfer in buildings. As a result, the moisture transfer efficiency of HVAC equipment has changed little even though removing moisture from a hot humid air stream during a cooling process may require 2 to 3 times more energy than simply cooling the air with no moisture transfer. Furthermore, the Intergovernmental Panel on Climate Change predicts that the demand for cooling in buildings will increase 30 times over this century meaning that moisture transfer efficiency will become even more important.*******The proposed NSERC Discovery Grant aims to improve the moisture transfer efficiency of HVAC systems by studying two moisture exchangers:****(a) liquid-to-air membrane energy exchangers (LAMEEs), a recent development of my research group that received a NSERC Synergy Award, and****(b) desiccant-coated energy wheels, an established technology.****This will be achieved by conducting experimental and numerical studies on three surface phenomena: (1) FROSTING, (2) FOULING and (3) SORPTION in these energy exchangers, which are important for practical application of the two moisture exchangers noted above (LAMEEs and energy wheels). Thus, this Discovery Grant research will address the growing need for energy-efficient HVAC systems that control moisture in buildings, while providing data that will improve the fundamental understanding of heat and moisture transfer processes and phase change at surfaces.***