By: Neil Mehltretter
Many facilities have issues with compressor room temperature regulation. This is due in large part to poor planning. Too often the compressor room is the last part of the facility considered when building a new plant or retrofitting an old one. As a result, the compressed air system is installed wherever there is room left—cramped spaces, alongside boilers or other equipment. Most compressed air systems have standard temperature ratings between 40 oF and 115 oF. However, considering that refrigerated dryers and heated desiccant dryers have correction factors when inlet temperatures rise above or fall below 100 oF, careful consideration should be taken into account for ambient conditions for both summer and winter.
Ventilation has a huge impact on the ambient temperature in the compressor room and is often the missing link to temperature regulation issues. Here are four factors to consider when designing the ventilation for your compressor room.
1. Inlet Air: The compressor room needs a sufficient source of inlet air. The recommended size of the opening can often be found in the equipment manual. If you have multiple pieces of equipment, you can either have one large opening or, better still, separate openings for each piece of equipment. The inlet air opening should have thermostatically controlled louvers/dampers to automatically open and close based on the temperature.
2. Recirculating Ductwork: Compressors produce a lot of heat (approximately 2550 Btu/hp). This heat needs to be removed otherwise the ambient and operating temperatures will increase, reducing the system efficiency, and in extreme cases, cause equipment shutdown. Again, it’s best to have thermostatically controlled louvers/dampers on the ductwork. In the winter, the warm air can be recovered and recirculated to the compressor room or an adjoining room to provide space heating. In the summer, the warm air can be ducted outdoors.
3. Exhaust Fan: Ancillary equipment in a compressed air system, such as refrigerated dryers, can require significant amounts of cooling air. If this is the case, an exhaust fan may be required to provide additional airflow.
4. Cooling Air Flow: Be careful of recirculation when planning where each piece of equipment and ducting will be placed. This picture below shows hot air inadvertently recirculating to the cooling air inlet:
This image shows the ductwork corrected so the exhaust is now directed towards the roof and the cooling air inlet can no longer inadvertently ingest the warm air:
There are a number of factors to consider when planning the ventilation for your compressor room, these are just a few of the major components. The best advice is to talk with an HVAC specialist as well as the compressed air equipment manufacturer to make sure you will have the proper supply of cooling air for your equipment. Taking the time to plan the compressor room will help eliminate temperature swings, equipment downtime, and keep your system as efficient as possible.