Air-cooled condensers
Unlike evaporative condensers, air cooled condensers capacity, which belongs to the dry bulb ambient temperature, not the bulb. If the working pressure in the condenser, not to become too high, that the plant is expensive to run capacitor with a large surface area should be used. This limit the practical upper size air-cooled condensers. Their use in air conditioning was usually confined to units with a capacity of less than 70 kW, although they were used for duties as high as 2000 kW, in areas with moderate climate.
Hot gas, leaving the compressor desuperheated for about 5 percent of the heat-exchange surface, with the subsequent condensation in the next few 85 percent, with a small drop in temperature condensation-related frictional pressure losses. A certain number of sub-coolant can happen. Additional heat-exchange surface can be helped hypothermia, achieving an increase of approximately 0.9% in cooling capacity for every degree the temperature of the liquid drops, according to ASHRAE (1996).
Propeller fans, direct dialing for a split capacitor motors are most commonly used to promote airflow, although axial or centrifugal fans also sometimes accepted.
Fan powers of approximately 20-40 watts per kW of cooling power. Noise is often a problem and it will be even worse if there are no barriers to entry or exit of the air ways. Although vertical fan arrangements are possible, with the horizontal cooling air path, these are susceptible to wind loads and recommended condenser coil must be horizontal, vertical cooling air path. Propeller fans will not supply air from any singificant external resistance. It follows that the connection duct then possible if it is not used fans.
In 20-degree difference between the input dry bulb thermometer temperature and condensing temperature, often in accordance with overly large condenser surface areas. Air-cooled condensers are growing in popularity because of lack of water, pipelines, consequent, easy operation and freedom from any health risks associated with the use of water spray.
Another objection to their use, that the power of the refrigeration system is progressively reduced as the ambient dry thermometer rises, but suddenly stops when the high pressure cutout works. A partial solution is to arrange for some of the compressor be unloaded if the condensing pressure rises, before it reaches the cut-out point. Continuation of work on low-power conditions possible for the design of the surrounding dry ball. It is a good plan to choose, air cooled condensers for work at an ambient temperature of two or three degrees higher than the design value chosen for the rest of the system of air-conditioning...
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Condensers and cooling towers