In Focus: Industrial Heat Transfer 0

Industry creates heat, and disposing of that heat is a never-ending challenge for designers of industrial facilities. Industrial cooling methods involve transferring heat from a solid object to a fluid or from one fluid to another for disposal or use.

As part of this process, heat-generating industrial machines must have a component to transfer heat into a fluid called the coolant. This component is called a heat sink. These take many form but generally consist of a piece of thermally conductive material in contact with both the heat source and the fluid to provide a passage for heat transferal. The heat-dissipating ability of the heat sink is directly dependent on the conductivity of the sink’s material and the amount of surface exposed.

The heated fluid is cooled by a device called a heat exchanger. Here another fluid is used to conduct and dissipate the heat. An automobile’s radiator is a heat exchanger using air as the conducting fluid. Other devices incorporating heat exchangers include air conditioners, heaters and electrical generators.

Industrial cooling systems employ air, water or oil as coolants. In some systems, water is heated and transferred to a cooling tower where it evaporates and dissipates into the atmosphere. Here both water and air are being used as coolants.

Cooling towers are an attempt to overcome some of the disadvantages of using once-through water for industrial cooling. For instance, an old-style facility using once-through water would typically use about 100,000 cubic meters of water per hour. This would be taken from some nearby body of water and returned to it after use, raising that body’s temperature significantly. Such facilities were an environmental hazard, and the cost of pumping so much water was enormous.

A cooling tower system can do the same amount of cooling with less water, because it is only necessary to replenish the amount of water that has evaporated rather than the entire amount. In a typical cooling tower system, this replacement rate is about 5%.

Systems with air and water cooling components are typical for large industrial applications, but air cooling alone is sometimes used for smaller jobs. Many industries cool machinery by blowing air over it with blowers or vents. The machine is a heat sink, so fins or other protuberances are sometimes added to increase surface area.

Oil, an electrical insulator, is often used for cooling electric devices. After heating, oil passes into a radiator acting as a heat sink. From here, the oil may be air-cooled or sent to a chamber for gas decompression. Oil has a higher evaporation point than water, so it can be used to disperse greater amounts of heat than a water-cooled system can.

Photo by ER24 EMS (Pty) Ltd.

Original Article on Greener.Ideal

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