Co2 systems

[RGover]

Hi has any one come across transcritical systems working on Co2, I know that Linde have a number of systems installed ove europe?

[iced]

Star Refrigeration are punting a small one, athough I believe they dont have any tried and tested in the field

[NoNickName]

Yes, I have. Linde, Knudsen Koling, Ahlsell.... questions?

[750 Valve]

There is one installed in a supermarket in Adelaide Australia

[RGover]

Hi all thanks for replys, I was after some information with regards the Transcritical side of things, i believe there are no condensers on this type of system?

[NoNickName]

What was called condenser in a subcritical or normal cycle, here is called "gas cooler".

[GXMPLX]

You don´t condense in a transcritical system so you don´t have a "condenser" but you do have a heat exchanger that does the same function: reject heat of compression+heat absorbed.

[RGover]

How does the gas cooler work? how do you get liquid?how do you maintian liquid pressure?

[NoNickName]

the gas cooler does what it says: it cools the gas, but being supercritical, it doesn't condense, so you don't get liquid.

After the gas cooler, a special regulation valve is installed, which lowers the pressure (it's a throttling device, like a TXV, but unlike a TXV it doesn't throttle liquid). As the pressure lowers, the gas approaches the critical pressure and transforms into liquid.

The difference between a normal cycle and a transcritical one, is that in the latter liquid forms after the throttling device, while in the former cycle liquid is present already before of it.

[RGover]

Thanks all is becoming clear.