Heat exchangers are a device used for transferring heat from a hot medium to a cold medium. The heat transfer can be from liquid to liquid, liquid to gas, or gas to liquid mediums. Liquids like, synthetic oil and water are widely used as heat transfer mediums in heat exchangers.
How it works
Heat exchangers are manufactured using material that has good heat conducting capacity. Metals like Aluminum, stainless steel, and copper are widely used for manufacturing because of their excellent heat conducting properties. Heat exchangers are designed in different shapes and sizes according to the requirements of the application. Based on their shape, heat exchangers can be classified into plate and tube types. Metal fins are attached to the plate or tube to increase the heat transfer area and increase its efficiency. If metal fins are attached to the tube then it is called tube fin heat exchanger and if it is attached with the plate then it is called plate fin heat exchanger. The size of the fins play important role in deciding the efficiency of the heat exchanger.
Usually, hot and cold mediums are separated by a wall which prevents two mediums from getting mixed. The separator wall is manufactured using material that has good heat conducting properties.
Water to air heat exchangers
Heat exchanger which transfers heat from water to the air is called water to air heat exchanger. There are many applications in which heat exchangers use water as a heat transfer medium since it is cheap and available in abundant quantity. Other advantages of water are it is a good conductor of heat and it has a low viscosity. Though it is a cost effective solution, the use of water also has disadvantages. Freshwater contains minerals like aluminum, copper, iron, and sodium. Water is not an ideal material for use in heat exchangers used in electronics devices. A higher level of ions in the water can cause an electrical short circuit and damage the electronic device. To overcome this problem, deionized water is used in the heat exchangers used for electronics devices, because deionized water contains fewer ions and there are fewer chances of short circuits.
Uses of water to air heat exchangers
Water to air heat exchangers is used in the applications like refrigeration, process cooling, air conditioning, and waste heat recovery.
Maintenance of water to air heat exchangers
Water to air heat exchanges needs regular maintenance. Heat exchangers which use metal must be checked regularly for leakages. Untreated water is corrosive to some metals because it contains dissolved oxygen. Sometimes, prolonged use of a heat exchanger or exposure to the wrong pressure or temperature can cause leakage, and it can degrade the performance of the heat exchanger. There are chances of leaking heat exchangers damaging other components of the application. It is necessary to clean the heat exchangers regularly because the accumulation of dust on the fins and outer surface of the tube/plate can degrade the performance of the heat exchanger.