Experimental and theoretical aspects of membrane based water cooling system

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Chemical Engineering, Turkey

Approval Date: 2017




In the chemical industry, to cool the process water, cooling towers are installed. In towers, hot water directly contacts with air flow. With sensible and latent heat, mass transfer between two phases, water temperature is decreased. Water evaporates during the operation and a respectable amount of energy is transferred to the air stream. Although, the cooling tower is an efficient process to cool the water stream, water pools placed under the towers tend result in growth of bacteria and algae. This problem grows with time and contaminates parts of tower. For smaller capacity towers, the problem reveals itself immediately. Although antibacterial chemicals are used to clean the contaminated parts, a permanent solution is proposed by membranes. Membranes are developing technology spreading to different areas such as separation, treatment and dialysis. Membrane contactor is one of the usage type of membranes and it allows heat and mass transfer between two phases without mixing into each other. As membrane geometry, hollow fiber membranes provide large surface area per volume. In this study, polysulphone hollow fiber membranes are chosen since they are hydrophobic. Experimental and theoretical analysis of membrane based cooling system was conducted by seven independent variables which are water flow rate, air flow rate, transmembrane pressure, module length and number, inlet air and water temperature. Results shows that water cooling was achieved approximately between 4- 9˚C and mathematical model matches with experimental results.