To Insulate vapor line or not

[tbirdtbird]

We have done a fair number of aftermarket AC in vintage cars here, and of course they are TXV jobs.
It is clear that the TXV needs to be insulated.
A passerby wondered out loud the other day why we did not insulate the entire return line from the evap.

Comments?
Dave

[DetroitAC]

You can insulate it, it will improve AC performance a few %

It's usually not done because it makes the suction line bulkier, is a fire risk, traps water and could corrode pipes or crimps. If it's done well, there is nothing wrong with doing it

[tbirdtbird]

Comments from all experts welcome.
Would there be thermodynamic consequences.....

[DetroitAC]

There would be thermodynamic consequences, the suction gas would be cooler and more dense, the mass flow through the compressor would increase, cooling capacity would increase.

[bohica2xo]

Thunderbird

I generally use foil faced fiberglass cloth to stop radiant heat on the suction line where needed . It is not very thick, fits in most places. Only complaint is that it looks like something we sent to the moon...

https://www.mcmaster.com/87715K49/

Well we kind of did use this stuff on spacecraft.

Secure it with straps like this if you have a hot zone like a turbocharger to deal with:

https://www.mcmaster.com/1601T61/

Energy is energy. On some systems you will see the liquid and suction lines bundled together and insulated. The plan there is to pick up some subcooling on the liquid line.

Mercedes used the suction line with a heat exchanger to cool the fuel in the engine compartment on some cars.

.