Air Cooled Heat Exchanger Design

Air-cooled heat exchangers are generally used where a process system generates heat which must be removed but for which there is no local use. A good example is the radiator in your car. The engine components must be cooled to keep them from overheating due to friction and the combustion process. The excess heat is carried away by the water/glycol coolant mixture. A small amount of the excess heat may be used by the car's radiator to heat the interior. Most of the heat must be dissipated somehow. One of the simplest ways is to use the ambient air. Air-cooled heat exchangers (often simply called air-coolers) do not require any cooling water from a cooling tower. They are usually used when the outlet temperature is more than about 20 deg. F above the maximum expected ambient air temperature. They can be used with closer approach temperatures but often become expensive compared to a combination of a cooling tower and a water-cooled exchanger. Typically an air-cooled exchanger for process use consists of a finned-tube bundle with rectangular box headers on both ends of the tubes. Cooling air is provided by one or more fans. Usually the air blows upwards through a horizontal tube bundle. The fans can be either forced or induced draft depending on whether the air is pushed or pulled through the tube bundle. The space between the fan(s) and the tube bundle is enclosed by a plenum chamber which directs the air. The whole assembly is usually mounted on legs or a piperack. The fans are usually driven be electric motors through some type of speed reducer. The speed reducers are usually either V-belts HTD drives or right angle gears. The fan drive assembly is supported by a steel mechanical drive support system. They usually include a vibration switch on each fan to automatically shut down a fan which has become imbalanced for some reason   The air-cooled heat exchangers are mostly used when the plant location and the ambient conditions do not allow an easy and economic use of other cooling systems. Specifications : Lower environmental impact than shell and tube heat exchangers thanks to the elimination of an auxiliary water supplyApplications : Reduction of maintenance costs No problem arising from thermal and chemical pollution of cooling fluids Advantages : Easy installation by bolted assembly Flexibility for any plant location and plot plan arrangement(installation over other units) Air Cooled Heat Exchangers Manufacturer INDIA Heat Exchanger Manufacturers INDIA