How to save energy costs on my Compressed air system?
I think we are all aware that the energy costs of running an air compressor can be very high. But are you aware of exactly how high they can be? Also, what can you do to reduce the costs of running your air compressor? This article can give you some ideas what to look into with the aim of reducing your energy costs.
How much does it cost to run an air compressor?
Of course this is a little bit like ‘how long is a piece of string?’ but there are some guidelines you can use to get a good ball park figure.
If you have an 11KW compressor running 8 hours a day 5 days a week, a good estimation for the electrical cost of running this compressor is:
Cost of running the compressor = 11 x 8 hours x 5 days x 50% x 10p = £22.00 per week
(This assumes a 50% on-line duty cycle and a 10p per KWh power cost)
This equates to just over £1,100 electrical cost every year just for the compressor. This is rather an over simplification of the real situation, since we are not taking into account the compressor ‘run on’. Typically an air compressor is designed to ‘run on’ for about 10 minutes after it has finished making air before finally shutting down. When the compressor is on ‘run on’ it is only using about 30% of full load power.
All larger fixed speed screw compressors ‘run on’ to reduce the impact of start up on electrical motors and electrical supply issues. The ‘Run on’ typically adds 25% to the electrical costs of running fixed speed compressors giving us a more realistic energy cost figure of £27.50 per week for this compressor and an annual cost of nearer £1,500 per year.
Obviously, if the compressor is bigger than 11KW the costs will increase proportionately. Similarly if the compressor is on line for more than 50% of the time this will also increase the costs proportionately.
How can I save energy costs on my Compressed air system?
There are a number of things you can do to save energy costs on my Compressed air system. Some of these are easy to achieve with little or no incremental costs some are more complex and strategic which require planning and investment. All should be built into your business plans and company regular maintenance procedures.
Lets start with the easy ones
1/ Reduce the operating pressure of your compressed air system
This is an easy way to reduce operating costs of your compressed air system. Turning down the pressure of your complete air system has a number of benefits.
- The compressor is working less hard so uses less power
- Less air is used by the equipment using the air
- Any air leaks in the system waste less air
- Air pressure losses in the pipework are lessened
As long as the air pressure is high enough to for all the equipment in the system, the air pressure should be set as low as possible.
2/ Shut down your compressed air system overnight
Again this is an easy way to reduce the costs of running your compressed air system. In an ideal world where there are no leaks in the system this won’t have an effect, but all systems have leaks and having your compressor running through the night adds no value and costs you money.
Take a look at our next article in this series ‘how do i reduce the running costs for my compressed air system?’
The British Compressed Air Society (BCAS) the UK trade body for Compressed Air Manufacturers and Distributors have produced a white paper on saving energy costs on compressed air systems. Click here to download the BCAS efficiency white paper