Every compressor generates heat, but if you let your compressor get too hot, efficiency and reliability are likely to suffer. Cooling your air compressor can minimize costs and result in fewer breakdowns and longer life. Here’s an explanation of why cooling matters and how to achieve it.
Protecting an Essential Asset
An industrial compressor is a significant investment. It powers a host of manufacturing equipment. If the compressor stops working, tools, actuators, conveyors and spray systems might fail, too.
Production stoppages due to compressor breakdowns can be very expensive. Delivery dates could be missed, quality might suffer, and it could take costly overtime to get back on schedule. That’s without considering the cost to repair the compressor.
The prudent course of action is to consider during the purchasing and installation process how you will cool your compressor. Then, once it’s in service, schedule time each month to inspect and maintain the air compressor cooling system.
Understand Why Cooling Matters
Compressing a gas into a smaller volume raises its temperature. In the case of an industrial air compressor, ambient air drawn in at 70°F can be discharged at 200°F or more. That creates two problems:
- Hotter air holds more water vapor. If left to condense in the air storage and distribution system, this may cause corrosion and other problems that will affect end-use equipment and operators.
- Every compressor is designed to run within a particular temperature range. Moving above that range could accelerate the breakdown of the lubricating oil and reduce the already tight clearances between moving parts. With a cool air compressor, life and reliability improve.
Methods of Compressor Cooling
There are a number of cooling techniques that may be used singly or in combination, depending on the cost and complexity of the compressor and the performance and life expected. These are:
- Oil cooling
- Forced air cooling
- Water cooling
- Natural convection
Oil cooling uses the oil that’s injected into a compressor for lubrication and sealing. In a rotary compressor, the oil absorbs heat as it moves around the screws. As the oil is recirculated, it passes through a heat exchanger where heat is dissipated to air. To maximize heat transfer, some compressors have a fan that blows air over the radiator.
Two stage compressors use an intercooler between the first and second units. This lowers the temperature of the compressed air before it goes through the second stage. Intercoolers are a type of radiator where energy from the hot air is transferred to ambient air.
Forced air cooling refers to blowing air over the compressor housing and, in the case of two stage compressors, the intercooler. Most compressors use either axial or centrifugal fans cooling fans, the latter being found in higher-capacity and higher-quality units.
Water cooling is much like the cooling system used for a car engine. Water is pumped through tubing around the compressor body, where it picks up heat that is subsequently shed in a radiator.
Natural convection refers to features that increase surface area and maximize the opportunity for heat to move into the surrounding air. These features, usually fins of various types, are often employed in conjunction with forced air cooling.
Impact of Compressor Enclosures
Industrial operators often put compressors in a dedicated room or enclosure. This is done to minimize workplace noise and to control compressor operating temperature. However, an enclosure can sometimes create as many problems as it solves.
Cooling relies on maintaining a large temperature differential between the heat of the compressor and its surroundings. While ambient air won’t reach compressor discharge temperatures, a poorly designed enclosure could result in it being far hotter than anticipated.
A common issue is exhaust air getting drawn back into the enclosure. This recirculation can raise the temperature significantly. Other issues include having too little airflow through the enclosure and too little free space inside. Both can result in operating temperatures far above the suggested safety levels.
Advice for Compressor Cooling
Keeping a compressor from getting too hot depends on good airflow and carrying out regular preventive maintenance. Here are some tips for both:
- Ensure louvers are open for air to enter and exit the compressor room.
- Duct intake air from the coolest and driest possible source. This is usually low, near the floor. (In warm climates, consider investing in an air compressor air cooler.)
- Ensure exhaust air doesn’t get pulled back into the compressor room. Raising the exhaust up high should help.
- Change the intake air filter before it becomes visibly dirty. A blocked filter increases suction pressure and forces the compressor to work harder to deliver air at the required pressure and volume. (Consider implementing a pressure gauge to monitor the differential.)
- Replace oil and oil filters at the manufacturer recommended intervals, or more frequently.
- Keep cooling fins and the air compressor cooling fan clean to maximize heat transfer.
- Clean radiators and heat exchanger coils — such as those in intercoolers — to ensure maximum effectiveness.
To some compressor operators, exhausting hot air to the outside seems like a waste of energy. This is especially true if the compressor runs all the time. To address this, some facilities use the air for heating during winter months, or even for processes that benefit from warm air, such as drying.
Find the Compressor That’s Right for Your Operation
When choosing an industrial air compressor, buyers typically review specifications for efficiency and output — but often overlook cooling. This is a significant omission, given the importance of limiting peak operating temperatures.
Kaishan Compressor USA views cooling as an essential element of compressor design because it has a major impact on the life and performance of the machinery. Every compressor in the Kaishan product line is designed with systems for effective temperature control. Compact, belt driven KRSB and KRST models incorporate centrifugal cooling fans while the direct drive KRSP and KRSP2 compressors feature axial cooling fans.
In addition, Kaishan compressors use coolers designed and manufactured in-house. This gives us complete control over quality, performance and other specifications, and permits the use of oversized coolers with no cost penalty.
Choosing the right compressor for your operation is not straightforward. Kaishan can help you determine the right equipment for your application and type of usage. Contact us today to connect with a compressor specialist.