When buying a new compressor, it is important to select the right model for the application. The right compressor will ensure energy and maintenance costs are minimised, and also deliver long term operating cost savings. Selecting the wrong compressor for the application can lead to thousands of dollars wasted in inefficiencies.
Top 10 things to consider when buying an air compressor:
What is the compressed air being used for?
The air compressor should be selected based on the intended application. It is therefore important to understand how the compressed air will be used in the application to get an ideal of how much air is needed. For existing systems, a thorough air audit will help the buyer determine an exact usage profile, which can then be used to make informed decisions on requirements.
Where will the compressor be located?
The location of the air compressor is an important factor. For instance, if it is going to be installed outdoors, it is important to consider factors such as shelter and weatherproofing. For indoor installation, ventilation, size and configuration will need to be considered. The key to a successful installation is sufficient access for maintenance.
How much pressure is needed for the application?
Calculating the minimum pressure required is vital to maximising efficiency. Every increase of 50 kPag (0.5 bar) in operating pressure results in additional energy consumption of 4%. When applied to a 200 kW compressor, an increase of 140 kPag (1.4 bar) in operating pressure results in an increase of over 20 kW in energy consumption, leading to increased costs.
How much Free Air Delivery (FAD)?
FAD refers to the maximum amount of air the compressor can produce, measured at inlet conditions. Ensure when selecting a compressor that the air flow figure quoted is measured in terms of FAD. Some manufacturers may quote figures from the internal parts of the compressor; also ensure the capacity is based on the operating pressure required for the application.
How many kilowatts?
Look for a compressor with the highest FAD for the same amount of input power – this means it is a more efficient compressor. Lower kilowatts equate to reduced energy usage and operating costs in the long term.
What size air receiver?
Air receivers act as a buffer for air compressors against constantly cycling on and off load. Larger air receivers not only increase compressed air storage but also protect against cycling, excessive energy usage as well as wear and tear on the compressor. Having an oversized air receiver is better than an undersized model.
Features to look for
Depending on the size and type of compressor, one should look for features such as Variable Speed Drive (VSD) that may save more money on energy costs but isn’t suited to every application; less moving parts, which will reduce maintenance requirement; cast iron construction; stainless steel control piping; and efficient coolers.
It’s important to know what amperage is available at the premises where the air compressor will be installed. Each size and type of compressor will have different power requirements so the premises will need to be adequately powered to operate the compressor.
What control system is best?
There are a number of different control systems available to configure and operate the compressed air system. The best control method will also be determined by the usage profile in terms of how much air is used and when it is used. The usage will dictate the most appropriate type of control to maximise efficiency and reliability. Popular control types include start/stop control, constant speed unloading, VSD, modulation and variable displacement.
Moisture removal is a key consideration in the selection of an air compressor. As air compresses, it produces moisture that can cause instrument/equipment damage or product spoilage if not removed. Correct aftercooling, drying and filtration can help achieve the right air quality.
Buyers seeking expert advice can consult with Southern Cross Compressors Australia Pty Ltd on their compressor requirements.