Evaporative Cooling Case Studies
Cooling the Compressor Room
Riverside Plastics Limited of Pontypridd, Wales, are a manufacturer of co-extruded bottles for the packaging of toiletries.
In the compressor house at its factory in Treforest, temperatures were rising to above 35°C on certain days and seriously effecting the efficiency and performance of the three compressors.
A single side discharge EcoCooler has been installed feeding air to the air intake side of the compressors. A thermosat was connected to the cooler and the extract fan. Now as the compressor house temperature rises the extraction and EcoCooler are turned on.
As the temperature rises further the evaporative cooling is enabled and the fan speed increases automatically to control the temperature.
The EcoCooler forms the forced intake element of the ventilation system for the compressor house.
The increase in relative humidity to the compressor has no effect on the performance of the dryer since the air is always passed from the aftercooler to the dryer in a saturated state.
There are benefits to keeping air compressors cool and well ventilated:
- Hot air is less dense than cool air. A typical screw compressor produces 6% less volume of compressed air at 30°C than at 15°C
- After compression the air is cooled in an after cooler which uses oil as a heat transfer media. In extreme temperatures this oil becomes hot and the compressor will automatically shut down.
- At high temperatures the oil will degrade faster and form ‘laquering’ which can lead to blockages in the narrow bores of the heat exchanger circuit.
- The heat from the oil is transferred to the compressor house typically using fan assisted heat exhangers. If there is inadequate ventilation this air can be recircled back into both the compressor intake and the oil cooler causing all of the above problems to occur.