How to choose the condenser and the cooling tower

To increase the cooling power, one can take advantage of the vaporization energy of water sprayed through the air stream. The principle is the same as when we spray the face in very hot weather: the vaporization of water cools our skin. Either the spray is that of the water flowing in the condenser, or it is water independent of the water of the condensation circuit that is sprayed.

Overall selection criteria

Energetically, the solution of a direct cooling of the refrigerant by the outside air has advantages, since all the intermediaries (and their consumptions) are avoided and so the expensive maintenance of the cooling tower. Today, the condensing pressure of air condensers is well managed by the arrival of the electronic expansion valves. This is the solution commonly adopted when the refrigeration unit can be placed on the roof: the condenser will be part of the “monobloc” system.

Logically,  duct cleaning washington dc we will find the air condenser on the roof. But the refrigerating machine is sometimes located in the cellar. In this case, it is excluded to trust “natural ventilation”, “spirals”, … the temperature in the cellar could rise strongly and the condenser would be swept by air already warmed. The condensing pressure of the fluid would rise and the compressor would see its consumption increase sharply. In hot weather, the compressor could not follow and trigger its high-pressure switch.

duct cleaning washington dcThe evacuation of the heat requires a real sweep by a cool fluid and it is up to the design office to compare 2 solutions:

Either an air duct is provided to bring the outside air to the condenser and evacuate the heated air (the generated pressure losses create consumption to the fan).

Either it is decided to place a water condenser and transfer the hot water to the roof to cool it in a cooling tower.

The transfer of heat by this second solution is more efficient (good water exchange coefficient, low consumption of a pump compared to a fan), … but there is investment and consumption of the tower. An overall assessment must be made.

Sizing parameters

To increase the performance of the compressor, it is advantageous to lower the condensation temperature. In other words, it is necessary to increase the exchange surface and increase the flow rate of water or air. The “pinch”, that is to say, the difference between the temperature of the cooling fluid at the condenser outlet and the temperature of the refrigerant will be minimal. But the investment and the pressure drops will be increased, and therefore the consumption of the pump …

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