Rotary air compressors will always require cooling – the compression process naturally generates heat, so it’s vital to keep equipment running at suitable temperatures to avoid breakdowns and malfunctions.

There are a few options here, with the primary cooling methods being either air or a chilled liquid coolant.

Choosing between a water cooled compressor or an air-cooled model depends on:

  • The space you have available.
  • The size of your compressor and the facility.
  • The type of compression tools and equipment you use.

Here we’ll explain how a water cooled compressor works and the difference between this air compressor and an air-cooled alternative.


How Does a Water Cooled Compressor Operate?

We’ll start with working through the functionality of a water cooled compressor. 

The liquid coolant comes from an external unit, cooling the air and other gases in the compression equipment. Each compressor has a cooling circuit with a shell and a tube exchanger.

Given that greater space is required for the water-cooling equipment, these are most commonly used in air compressors with higher horsepower.

For many businesses, the key advantage of a water cooled compressor is that they can repurpose the heated water, to warm boilers or central heating systems.

That efficiency means that the site can downsize to a smaller boiler since the demands on your hot water system will reduce.


Is a Water Cooled Compressor More Cost-Effective Than Air Cooled?

Energy costs should always be part of budgeting for an air compressor since they will require energy to run.

Let’s compare air vs water cooled compressors side by side:

  • Energy usage: you’ll need more power to manage an air-cooled unit than a water-cooled model.
  • Utility costs: water cooled compressors cost more in terms of water supply, water treatment and electricity, so air-cooled compressors can be cheaper to run.
  • Cost offsets: both water-cooled and air-cooled compressors produce reusable heat resources. Businesses can use liquid-cooled water to preheat boilers and heated air from air-cooled systems to power a fluid heat exchanger or warm rooms.

As you can see, there are pros and cons to both, so it’s all about how much capacity you need from your compressor and which option is best suited to your processes.


What Are the Requirements for a Water Cooled Compressor?

So, if you think a water-cooled screw compressor is your solution, you will need to consider the water sourcing since the quality of the water cooling system needs to be good.

For example, if your commercial premises draws water from a natural water source, you will require a cooling tower and a closed-loop system. 

This system filters the water and ensures your compressor will last longer.

Suppose the building already has a quality water supply and filtration. In that case, other costs involved are maintenance of the closed-loop on-site system on top of the installation and maintenance of the compressor.


Water Cooled Compressors vs Air Cooled

If you’re not sure which is the right compressor, never fear! 

Here are the key questions to ask before making a decision.


What are your air demand requirements?

That means assessing the required horsepower, PSI and cubic feet per minute (CFM). Higher horsepower compressors can, of course, cope with higher air demands. The CFM indicates the air the compressor can produce per minute to arrive at an estimated PSI.

It’s best to think about the CFM and PSI ratings you need and then select a compressor to match those demands.


Are there limitations on the size or ventilation of the compressor room?

Next, you’ll also need to look at the practicalities. For example, your air compressor room needs to have sufficient space – or you might consider having multiple smaller compressors rather than one large unit if you have space restrictions.

However, water cooled compressors might not be suited for a smaller compressor room since you won’t find smaller model rotary screw compressors with water cooling systems.

Ventilation is also crucial. While an air-cooled compressor will need sufficient airflow, a water cooled model can suit a smaller space and higher temperatures. However, it remains essential to keep compressors away from boiler rooms or fumes.


Do you have a fixed budget?

Finally, budgets relate to ongoing operational costs as well as the installation of your compressor.

Water can be an expensive utility, so you’ll need accurate estimates as to the monthly cost factor, given that this will substantially increase your water bill. 

The best way to make an informed decision about the right cooling system for your air compressor is to analyse your applications and ensure the equipment you choose is fit for your purpose.