The air-cooled condenser is the standard of industrial refrigeration: finned tubes and fans reject heat to the outside air. It needs no water, its maintenance consists of cleaning the fins, and it can be placed anywhere. Its weakness is its dependence on ambient temperature: on hot summer days the condensing temperature exceeds 50 °C, capacity falls and consumption rises. There are housed (quiet) and universal (open) types.
In a water-cooled condenser the refrigerant condenses in a shell-and-tube or plate heat exchanger with water flowing through it; the water is cooled in a cooling tower and recirculated, or well or mains water is used. Because the condensing temperature can be held at 35–40 °C, the compressor uses 15–25% less electricity; the machine room is smaller and noise is lower. In return there is water consumption, scale and corrosion, tower maintenance and the risk of freezing in winter.
Rule of thumb: air-cooled at small and medium capacities (below 300 kW); water-cooled or evaporative condensers in large plants, hot climates and places where water is plentiful. Our condenser catalog gives the capacities of air-cooled and housed models at different ambient temperatures.