Calculating Compressed air leaks within a system

[rl424]

Hi all, new to the forum, but I was wondering if anyone could help me as I'm going round in circles. After completeing an air leak survey and noting the hole diameter, dB reading of the leak and knowing the pressure of the system (bar) how can I calculate the leak rate CFM and the Energy wasted (kW). Or is there some kind of standard/approximate table I can use.

Thanks in advance

 

[JaredJames]

I've done something similar in the past for testing various units.

You seal input / output of the unit and increase the internal pressure to a set value. You then take internal pressure readings over a set period (we used each minute for 15 minutes).

After which time you know the pressure drop over a set time which you can convert to leakage rate per unit time.

I'll try to dig out the equation for you (it's fairly simple), but if you could describe your setup it would help me determine if it's right for you.

 

[Charlied]

Hi all, new to the forum, but I was wondering if anyone could help me as I'm going round in circles. After completeing an air leak survey and noting the hole diameter, dB reading of the leak and knowing the pressure of the system (bar) how can I calculate the leak rate CFM and the Energy wasted (kW). Or is there some kind of standard/approximate table I can use.

Thanks in advance

I've done this for my work also. I used a chart like this one for the flow calculation for an example of a 1/8th inch hole leak at 24-7. http://www.trident.on.ca/orifice-air-flow.htm
Divide the flow into the compressors capacity and find the percent of it's capacity. Multiply the compressor loaded kw by the calculated percent of the leak. That times the utility kwh rate is part of your cost. The other cost is the maintenance of the compressor for the percent of the leaks. The cost of air leaks in a large plant is mind-blowing.

 

[GT1]

You can try using the formulas at this link:
http://www.air-dispersion.com/feature2.html

 

[pmacias]

Hello and welcome to the forum! Calculating compressed air leaks within a system can be a complex task, but there are some steps you can take to estimate the leak rate and energy wasted.

First, you will need to convert the pressure of the system from bar to psi, as most leak rate and energy calculations use psi as the unit of measurement. You can use a conversion calculator or formula to do this.

Next, you can use a leak rate calculator, which can be found online or as a downloadable tool, to input the hole diameter, psi, and other relevant information to estimate the leak rate in CFM (cubic feet per minute). Keep in mind that these calculators provide an estimate and may not be 100% accurate.

To calculate the energy wasted, you will need to know the cost of electricity in your location and the operating hours of the system. You can then use the formula: Energy wasted (kW) = Leak rate (CFM) x Pressure (psi) x Operating hours x Cost of electricity per kWh. This will give you an estimate of the energy wasted in kilowatt-hours.

There are also tables and charts available from organizations such as the Compressed Air and Gas Institute (CAGI) that provide estimated leak rates and energy waste based on pressure and hole diameter. However, these may not be as accurate as using a calculator or doing the calculations yourself.

I hope this helps you in your calculations. It's important to regularly monitor and address air leaks in a system to save energy and reduce costs. If you have any further questions, don't hesitate to ask. Good luck!