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Posted by: gintable on 2009-12-26, 19:31:27
The refrigeration cycle has a component on it called a condenser. In a condenser, a refrigerant which is part of the refrigeration cycle that makes the cooling coils for the Air conditioning work, undergoes a process in which it is condensed from a hot/ high pressure vapor to a liquid which will be throttled to a lower pressure. In order to make condensation occur of the refrigerant, the condenser must reject heat to a secondary fluid. In a household air-conditioning, this secondary fluid is the air outside. However, in order to keep the condenser coil small, water is preferred due to its heat transfer properties. Air is pathetic at heat transfer compared to water. In order to save water, the loop of cooling water is circulated and somehow must be cooled. In order to cool the loop of cooling water, it is brought in to a cooling tower. In the cooling tower, the water mixes and evaporates in the introduced airflow. Airflow escapes the top of the tower at a more humid condition than when it entered. By evaporating the water, the remaining water is cooled, and then mixed with a smaller flow of make-up water to maintain the mass flowrate. By using cooling towers, a reliable method of rejecting heat of water exists, without encountering temperatures which are dangerous for the environment in high concentrations. Also, less demand is necessary for water delivery. To explain the operation of a cooling tower in a different way, it is a 5 stream chamber. Stream 1 is the warm water to be cooled Stream 2 is the dry air available in the background Stream 3 is the smaller flow rate of make-up water used to maintain the mass flow Stream 4 is the exhaust of humid air Stream 5 is the delivery of chilled water |
