Rotary compressor cooling

It's a long time since I can't explain myself about the following thing:

Motors of hermetic recip compressors, and scroll compressors are cooled by passing suction refrigerant, which, of course, usually has a low temperature; motor is placed into low pressure side. On the other side, the rotary compressors seems to be built "upside down": the induction motor is on the high pressure side, after the discharge port of the compressor. So, how is this motor cooled, since it's always staying in a very hot gas? On top of this, the compressor is usually wrapped in acoustic insulator, so it can't pass heat to surrounding air. I can't imagine why ALL the rotary compressors are built this way, with motor on the high pressure side.

Thank you!

The temperature in compressor heaven is about 70C/160F. You shouldn't be concerned until it is hot enough to boil water.

Rotary compressors have designed to work 100c to 120c.

Maybe it's something about thermodynamics, since the suction gas enters directly into compressor. There's no more superheat added by motor windings. There's another similar thread but there was no conclusion: http://www.refrigeration-engineer.co...ed-compressors

The rotary compressor on small scale units is cooled via the oil returns to the oil sump which is thereby cooled from the suction.

davidk, not just the Rotary, even few make scrolls are made this way. They are called "high side" design - motor cooled by discharge gas. The hermetic recips and standard scrolls that we see in market are "low side" design. Both have their own merits and de-merits - as per their manufacturers. All hermetics - scrolls, rotaries and recips - depend on gas cooling and need not have to conduct heat thru' their shells.