What is the duty cycle of A/C compressors?

Tiny
SALYEMEN
  • MEMBER
  • 2004 TOYOTA HIGHLANDER
  • 4.7L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 188,000 MILES
I do not have any problems, yet I have a question about car A/C
compressor.

What is the duty cycle of such compressors?

I plan to use one as compressor for refrigeration purposes as commercial freezer?

Is that possible?
Monday, December 7th, 2020 AT 6:13 AM

3 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Duty cycling the compressor means it only comes on when it is needed. Meaning if you did not duty cycle it and it stayed on all the time then you would need to vent the pressure as the compressor would just keep building pressure. However, you can't vent the pressure because then you would vent the refrigerant as well which we can't do for obvious reasons. This is why you hear the compressor come on and off.

Here is a guide that will help. I don't think it answers all the questions but it should help.

https://www.2carpros.com/articles/how-a-car-air-conditioner-works

As for if you can use the compressor, you can use it in any application that you want to but you need to have the rest of the components within the system as well. I am not sure how you were planning on hooking this up or to what system but the compressor could work but you need to account for the control to run it off and on.

Let us know more detail about how you are planning to hook this up and we can figure out if this is going to work.
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Monday, December 7th, 2020 AT 9:29 AM
Tiny
SALYEMEN
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I wanted to know if duty cycle of those compressors permits such long continuous operations.
For example the belt driven reciprocating air compressor has duty cycle of about 25%, meaning in a single hour we can run it only 15 minutes and the rest 45 minutes it should be shut down for cooling, and so on.
How long we can run the car A/C compressor continuously before it gets overheated, damaged for example.
On the other hand the rotary screw air compressors have 100% duty cycle, which mean we can run it for continuous duty without shut down periods.

Where do the car A/C compressor stand in that operation approach?
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Tuesday, December 8th, 2020 AT 11:31 AM
Tiny
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Okay, I understand. It is hard to say how long you will be able to run it because I just frankly have never seen it because they have a high pressure sensor that will cut them off. So they can build upward of 400 PSI in about 5 minutes of run time or less. So running wide open I would suspect much more the 5-7 minutes of continuous run time it would start be damaged or at least build too much pressure that it would not cool very well.

Are you able to set this up with a pressure gauge on it? If so, that will dictate when you need to cycle it. Here is a chart that gives proper pressures if you would like run it based on that.

Hope this helps.
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Tuesday, December 8th, 2020 AT 6:43 PM

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