Keeping Cool: Choosing an Air Compressor Cooling System

A cooling system is a vital part of an industrial air compressor. There are two fundamental sorts of cooling strategies to select from: air-cooled or water-cooled. Which kind of cooling system is healthier? It depends upon your compressor kind, the quantity of air you should cool, and the ambient circumstances. Listed below are some issues to contemplate when selecting between an air-cooled and a water-cooled air compressor.  


Why Do You Want a Cooling System for Your Air Compressor?

Air compressors generate warmth—and plenty of it. This is called the warmth of compression. All of it comes all the way down to the legal guidelines of physics: as the amount of a gasoline is decreased, each the temperature and strain go up in accordance with the mixed gasoline regulation: 

Keeping Cool: Choosing an Air Compressor Cooling System

The extra air that’s compressed, the extra warmth is created. Extra warmth can be produced within the motor and air-end of the compressor. In an oil-injected rotary screw air compressor, a majority of this warmth is eliminated internally by circulating oil. Nonetheless, the air popping out of the compressor continues to be extremely popular; typical outlet temperatures for an oil-injected rotary screw compressor could also be greater than 160°F. An oil-free air compressor or two-stage reciprocating compressor might have discharge air temperatures of 300-350°F. These excessive temperatures could cause issues downline in your compressed air system–significantly on your air dryers if not decreased. 

Most air dryers are rated for inlet temperatures of not more than 100°F. When temperatures are increased, the dryer can’t work as effectively or in any respect. Hotter air carries extra moisture, placing pressure on the drying system. If the dryers aren’t in a position to take away sufficient of the moisture, it’ll lead to condensation in different components of the distribution system because the air cools. Extra warmth can lead to different points as nicely:

  • Extra warmth can degrade seals and wash away lubricants in downstream instruments and gear, resulting in early failure of system elements. 
  • Failing to manage the warmth created by air compression will warmth up the compressor room and surrounding surroundings, probably resulting in overheating of the air compressor itself. 
  • If the compressor is working indoors, extra warmth generated by the compressor will put a pressure on air con methods in the summertime. 

An aftercooler is designed to dissipate extra warmth and mitigate these heat-related points. 

What Is an Air Compressor Aftercooler? 

Industrial air compressors want a cooling system to take away extra warmth generated by compression. An aftercooler is a kind of warmth trade system that absorbs warmth from the compressed air and carries it away the place it may be dissipated. Because the compressed air cools, it reaches its level of saturation. On this means, the aftercooler acts each as a cooling system and the primary stage within the drying system for compressed air. Actually, about 70% of moisture in compressed air falls out within the aftercooler, leaving simply 30% to be dealt with by the dryers. With out an efficient aftercooler system, the dryer will have to be outsized to deal with the extra moisture. 

Rotary kind air compressors are nearly all the time bought with an built-in after-cooling system. There are two major sorts of industrial air compressors: air-cooled and liquid-cooled, often known as water cooled. Each sorts of aftercoolers can present important advantages. An aftercooler will: 

  • Take away about 70% of the surplus moisture from the air, lowering pressure on the air dryer.
  • Be certain that air going into the dryer doesn’t exceed the temperature specs for the dryer. 
  • Defend downstream gear from extreme warmth and moisture. 
  • Enhance security and cut back hearth danger by cooling discharge air earlier than it is available in contact with compressed air hoses. 

Air-Cooled Compressors vs. Liquid-Cooled Compressors

Each air-cooled and liquid-cooled aftercoolers act as warmth exchangers, eradicating extra warmth from outlet air. The principle distinction is the medium used to switch the warmth. Because the names counsel, an air-cooled compressor makes use of air, and a liquid-cooled compressor makes use of a liquid, normally water or glycol/water combine. 

Air-Cooled Compressors

An air-cooled aftercooler makes use of ambient air to carry down the temperature of compressed air. That is by far the commonest type of aftercooler for rotary screw or rotary vane air compressors. Compressed air strikes via a collection of coils contained in the aftercooler. A fan blows cool ambient air over the coils, carrying away extra warmth. Cooling fins present further floor space for air to maneuver throughout, growing the warmth switch capability. As a substitute for mounting a fan with its personal motor, a belt guard air aftercooler (used on some piston-style compressors) makes use of airflow generated by the compressor’s belt system, which might avoid wasting area. 

An air aftercooler reduces the temperature of compressed air to inside roughly 15-20°F of ambient temperature, often known as the strategy temperature. If the ambient temperature is 85°F, you’ll be able to count on the air cooler to scale back outlet temperatures to about 100°F. On the similar time, a number of the extra water vapor drops out of the air because it cools. Condensation should be eliminated through a drain valve. 

Air aftercoolers present efficient cooling for many industrial compressed air purposes. They’re additionally easy to keep up. Nonetheless, an air-cooled air compressor requires loads of area and air flow to make sure ample airflow for cooling. Ambient air should even be comparatively cool; the aftercoolers won’t work nicely if the compressor room is allowed to get too scorching, which may result in air compressor overheating. The compressor should be situated in an space close to an out of doors wall or with entry to roof air flow to vent the surplus warmth outdoor. In some methods, it’s doable to seize the surplus warmth to supply heating for the constructing or carry out different work. 

Aire Tip: The optimum working temperature vary for an air compressor is between 50-85°F. Learn extra: Optimal Temperature Range for Compressed Air Equipment

Water-Cooled Compressors

Water-cooled aftercoolers use cool circulating water to carry down the temperature of compressed air. Whereas different liquids can be utilized in some instances, water is by far the commonest substance used for liquid cooling of compressed air. As compressed air strikes via the coils of the aftercooler, water flows across the tubes to hold away the warmth. A water-cooled system might be extra expensive to put in and keep, however liquids are way more environment friendly in carrying away warmth. Meaning they’ll dissipate extra warmth utilizing much less vitality. Water cooling usually can get compressed air to inside 10-15°F of the water temperature. There are two major sorts of water-cooled aftercoolers. 

  • A closed-loop water cooling system recirculates the identical water via the system. The water heats up because it is available in contact with the new pipes carrying discharge compressed air. The hotter water passes via a warmth exchanger that cools it again down earlier than it returns to the start of the trail. Alternatively, water might go via a refrigeration system to be re-chilled. (Course of industries utilizing refrigerated water for different functions could possibly draw on extra capability for cooling.) The warmth exchanger could also be just like an air-cooled aftercooler, with followers and cooling fins. A closed-loop system makes use of much less water total, although they may have to be inspected and topped off often. If the pipes are uncovered to the weather in a colder local weather, glycol can be added to the system to forestall the pipes from freezing and cracking. Nonetheless, this may cut back the warmth switch properties of the water. 
  • In an open (or evaporative) water-cooling system, a continuing provide of contemporary water is used to chill the coils containing compressed air. Water is sprayed throughout the coils and drains off or evaporates. In some services, heated water is reclaimed to be used in boilers, industrial processes or different “grey water” purposes. These methods use plenty of water, which is usually a price concern if water should be bought. 

An open water-cooling system usually depends on close by our bodies of water (pond, river, lake, nicely, and even ocean) slightly than counting on a municipal water provide. Nonetheless, water used for cooling should be high-quality. A water tower and filtration system will usually be wanted when utilizing environmental water. These prices should be thought-about when considering an open-water cooling system. As a result of constructing and sustaining a water remedy system is cost-prohibitive, these methods are extra generally utilized in course of industries that have already got this infrastructure in place for different functions. 

Ought to You Purchase an Air-Cooled or Water-Cooled Air Compressor? 

Which kind of cooling system is greatest on your air compressor? That relies upon partially on the air compressor measurement, your surroundings, and if in case you have an current cooling system. 

  • Air-cooled aftercoolers are cheaper and require much less upkeep, making them your best option for a majority of air-using purposes. Greater than 95% of rotary screw air compressors are air-cooled. An air-cooled aftercooler can deal with discharge temperatures of as much as 350°F and pressures as much as 250 PSI. 
  • Water-cooled air compressors are a more sensible choice for high-temperature purposes, excessive mud environments, very giant compressors, or the place the set up within the plant is opened and air conditioned. An open water-cooled system can deal with discharge temperatures of as much as 450°F and pressures as much as 435 PSI.

A water-cooled system might also be a more sensible choice if:

  • You don’t have ample area and airflow for efficient air cooling.
  • Ambient air temperatures get very excessive (90°F and above) frequently. 

Additionally it is doable to complement an air-cooled compressor with a separate trim aftercooler if air cooling shouldn’t be in a position to get outlet temperatures beneath 100°F. This may be particularly useful if further cooling is required solely when temperatures rise into the 90s and above in the summertime months. The ancillary aftercooler might be turned on solely when it’s wanted. 


Air-cooled Compressors Water-cooled Compressors
  • Inexpensive
  • Decrease upkeep
  • Easy operation 
  • Used to Warmth Facility
  • Increased cooling effectivity 
  • Quiet operation
  • Decrease area necessities
  • Higher cooling capability in excessive ambient temperatures
  • Requires more room
  • Arduous to maintain the compressor room cool
  • Doesn’t work nicely in excessive ambient temperatures 
  • Extra methods upkeep 
  • Increased working prices
  • Open methods require giant volumes of high-quality water
Typical Use
  • Common industrial compressed air purposes beneath 200HP
  • Excessive ambient temperature purposes 
  • Bigger HP purposes with giant volumes of air to chill (e.g., centrifugal compressors) 

Sizing Your Air Compressor Aftercooler

Aftercoolers should be sized appropriately to get the anticipated quantity of cooling. Sizing for an air compressor aftercooler depends upon 4 variables: 

  • The CFM of the air compressor
  • The PSI of the compressed air system
  • The discharge temperature of air from the compressor 
  • The ambient temperature

The extra air you might be transferring (increased CFM), the upper its strain, and the better the distinction between discharge temperature and required temperature, the bigger the aftercooler will have to be. Most air compressor aftercoolers are sized to carry compressed air temperatures all the way down to inside 10-20°F of the ambient air temperature or cooling liquid temperature, often called the strategy temperature.

Aire tip: When sizing an air-cooled aftercooler, all the time measurement it for the very best ambient temperatures anticipated in your surroundings at 100% humidity. 

Caring for Your Air Compressor Aftercooler

Your aftercooler required common upkeep for correct operation. That features: 

  • Usually drain condensate from the system. A zero-loss drain valve will drain extra liquid robotically whereas conserving compressed air. 
  • For air-cooled methods, examine and clear the fan system frequently. Maintain the coils and cooling fins freed from mud and particles, which is able to cut back cooling effectivity. 
  • For water-cooled methods, monitor water high quality frequently and examine and clear the system.

Want Assist Retaining Your Compressor Cool?

In case your air compressor is overheating, otherwise you’re having hassle getting compressed air all the way down to acceptable working temperatures for downstream gear, it could be time to try your aftercooler. We may help you establish whether or not you simply want some upkeep or when you want a bigger aftercooler system. 

Talk to an air professional in the present day. 

Source link

Leave a Reply

Your email address will not be published.