Insulating Vehicle A/C Lines

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Since summer is upon us her ein the Northern Hemisphere, its A/C Season. Not saying the A/c system in my Tacoma is inferior and was charged last weekend but I was wondering if anybody on here has had any experience insulating the A/C lines under the hood?

I know in Home HVAC systems, the lines which run between the pump and the wall of the dwelling are oftentimes insulated perhaps keeping some of the cold lines "colder"? Since the cold lines run through the Hot engine compartment, would insulating the lines further help keep them cooler?
 
It is not generally recommended. Info below taken from Stack Exchange because they explain it better than I can.

1. The cold side of the piping is after the evaporator, headed back to the compressor. Any loss here will not make a difference in the overall performance or efficiency of your AC unit.

2. Since the system is designed without the insulation, it may actually be detrimental to some of the working parts for it to be colder (may cause freezing of moving parts/evaporator). Engineers have taken all of this into account when designing the AC unit in the first place

3. Remember in order for condensation to form on this pipe it only has to meet two conditions: 1) pipe has to be cooler than the dew point; 2) there has to be humidity in the air. These conditions are very easily met in most situations.

Vehicle AC units are work pretty darn well considering what they have to do and the amount and quickness of cooling they have to do. Why mess with success. If you do, you could be introducing dynamics into the system they weren't designed for and you won't being doing much to improve the efficiency
 
I would think there would be a risk of "slugging" the compressor with liquid refrigerant, likely damaging it. Unlike a hermetic or scroll A/C compressor, an automotive compressor can't take any liquid returning, at all.
 
Originally Posted By: ad244
I know in Home HVAC systems, the lines which run between the pump and the wall of the dwelling are oftentimes insulated perhaps keeping some of the cold lines "colder"? Since the cold lines run through the Hot engine compartment, would insulating the lines further help keep them cooler?

The "coldness" of the lines is immaterial for the most part. The smaller high pressure liquid line coming from the condenser is warm, you want it to reject heat if possible before it reaches the evaporator. The low pressure gas line from the evaporator to the compressor (the one that's insulated in your house and often in a car) really doesn't go that far and thermodynamically it won't make much difference when it comes to affecting the output temperature at the compressor. What insulation may already be on there is sufficient.
 
On several of the Ford F150 sites, I've read where folks have insulated the cold side and increased the performance of the system, without any detrimental effects.
 
Those trucks normally work well. Something is wrong with yours. Was it charged by weight or some yahoo with guages and a can? Is the heater valve shutting the water off to the heater completely? Bad compressor or expansion valve?
 
Mercedes used to insulate the AC lines in the 1980s-1990s with Armstrong Tubolit insulation, which I believe Armaflex at the local big box is the successor to that.

I don't think it'll hurt, if anything it might protect the hard lines from chafing.
 
One benefit to insulating a portion of the line from firewall (..only part of the line run...) is to stop condesate from the sweating line dripping onto belt(s) and slinging droplets all over. Would not otherwise care and system does not need it. On smaller Honda engines, this resulted in considerable difference in accumulating dirt on the sound insulation material under the hood.
 
Originally Posted By: nthach
Mercedes used to insulate the AC lines in the 1980s-1990s with Armstrong Tubolit insulation, which I believe Armaflex at the local big box is the successor to that.

I don't think it'll hurt, if anything it might protect the hard lines from chafing.


I was just about to say this!
 
I bought pipe insulation from Home Depot and insulate the cold line in all my vehicles. On a 2007 Mazda I compared the un-insulated center vent out put temp vs insulated. The insulation helped the center vent temp by lowering the temp 2.5 F. measured with an accurate Digital thermometer. A worthwhile thing to do here in SW Florida. Ed
 
Chrysler actually started running a section of the high side line inside of the low side line. They decided cooling the high side was more important. They call it a internal heat exchanger.
 
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Originally Posted By: bullwinkle
I would think there would be a risk of "slugging" the compressor with liquid refrigerant, likely damaging it. Unlike a hermetic or scroll A/C compressor, an automotive compressor can't take any liquid returning, at all.


Considering the fact that oil and liquid refrigerant are added to the return line that is impossible.


The dryer/accumulator on my 95 Suburban was insulated from the factory.



On a side note I blew the thrust bearing out of a 2000hp turbin compressor chiller when I restarted it without water flow through the evaporator. The tech had recommissioned it but not run it but left the compressor thrusted out of center. He told me how to reset it over the phone but didn’t remember that the valve was closed on the chilled water return till it went bang. So you can get the systems to cold.
 
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Originally Posted By: Eddie
I bought pipe insulation from Home Depot and insulate the cold line in all my vehicles. On a 2007 Mazda I compared the un-insulated center vent out put temp vs insulated. The insulation helped the center vent temp by lowering the temp 2.5 F. measured with an accurate Digital thermometer. A worthwhile thing to do here in SW Florida. Ed


Good info. Can the 2.5 F decrease be attributed to a change in ambient conditions (humidity, temp) between the two temp measuring events, i.e. everything the same?
 
Ever thing was the same willbur. I was careful to watch for ambient differences and I did the tests within a few hours of each measurement and again several days afterwards. . Ed
 
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