Skip to main content

Rules of Thumb




Power and installation:

  • For every horsepower, a compressor delivers 4-5 cfm (m3/hr), at 100 psi (7 bar) pressure .
  • A 50 HP air compressor can produce up to 12 gallons / 45 liters of water per day (with only 8 running hours daily).
  • Air receivers should be sized about 4 gallon capacity for each CFM of compressor capacity. That's 9 liters per m3/h in metric units.

For example, a small 20 cfm compressor needs an 80 gallon air receiver.

Costs and energy savings:

  • On average, compressed air costs about 30 cents per 1000 cfm (1700 m3/hr). This depends on the size of the compressor and includes electricity, purchase price of compressor and maintenance costs.
  • A 50 HP air compressor will cost you about 25.000 dollars in electricity cost per year (at 6.000 running hours per year).
  • Every 2 psi (0.15 bar) of pressure drop in your system will cost you 1% extra in energy cost (this adds up quickly!!!)
Pressure - Rule of Thumb

  • Lowering Compressor Inlet Air Temperature 10° F (5.5 °C) will result in a 2% energy savings.
  • A two stage reciprocating air compressor is about 15% more efficient compared to a single stage unit.


Temperatures:

  • The typical discharge temperature of a rotary screw compressor (before aftercooler) is: 175°F or 80°C
  • The typical discharge temperature of a single stage reciprocating compressor is: 350°F or 180°C
  • The typical discharge temperature of a two stage reciprocating compressor is: 250°F or 120°C
  • In rotary screw compressors, every 18 °F (or 10 °C) above 200 °F (or 95 °C) reduces the compressor oil life by 50%!


The one rule of thumbs that amazes people the most is the amount of water that an air compressor produces!

Comments

Post a Comment

Popular posts from this blog

Decoding the Duty Cycle Rating of Piston Compressors Selecting the correct air compressor for your application can be a complicated process. Before making a purchase, operators need to specify the quality and amount of air their application requires. Each compressor technology (rotary, piston, centrifugal, etc.) has an optimal flow output, so users should choose compressor technology based on the compressed airflow requirement of their application. Some compressors, like rotary screw and centrifugal, are designed to run continuously at full speed while maintaining peak airflow (defined in cubic feet per minute, or CFM). The motors and cooling systems of these compressors are engineered to run 100 percent of the time without overheating. However, this isn’t true for all compressors. Piston compressors do not have the cooling capabilities to run continuously for extended periods of time. Therefore, each piston compressor must have a specified flow output and pressure, as...
Post a Comment
Read more

Using Compressed Air? Think again!

Using Compressed Air? Think again! We know this might sound strange from a guy who's all about compressed air... ... but did you ever wonder WHY and IF you really need to use compressed air? It might have been a very bad decision to make use of compressed air for your tools, machines, actuators, etc. Sure, some applications DEMAND compressed air. It's simply the only real option for it. And we know, compressed air and has many upsides: compressed air tools are very powerful they are safe to use can operate in very dirty environments are cheaper compared to their electrical counterparts can last a lifetime. I love all the benefits that using compressed air for your application brings.. but there is one very big downside.. Compressed air is EXPENSIVE. Very expensive. In fact, it's 7x - 8x more expensive compared to electricity. We talked about the cost of compressed air. And here's an example that shows exactly how and why using compressed...
Post a Comment
Read more

3 Ways to Save Money On Compressed Air

3 Ways to Save Money On Compressed Air What if you knew that your compressed air system was completely optimized… running happily day after day. No more waste of money and electricity… Because let's face it: wasting thousands of dollars per year on electricity, without you knowing it, sucks. Want to optimize your compressed air system? It's impossible to share the complete step-by-step system in an email, but I can get you started on the right path. Compressed air optimization #1: Air leaks As discusses in our previous blog: fix those leaks! Compressed air leaks are the number one energy wasters! The biggest, most rewarding, leaks will be easy to find. For the smaller leaks, you might have to do some extra work, but it will pay off! But more importantly, once you fixed most of the leaks, put a system in place to continually check for and repair new compressed air leaks. You can also use some stealth tactics like dividing your compressed air network in zones and shutti...
Post a Comment
Read more