Evaporator

[freezerman11]

Hi Guys,

Can anyone help me out with this,

We currently have a plant that runs on R22, they have a freezer room that runs at -25 degrees, one of the evaporators has a substantial leak, the evaporator currently in place is DX, however down the track they are wanting to swap everything over to Ammonia,

What we wish to do is replace the current Copper Evaporator with an Ammonia Evaporator so that when it comes time to de-commision the r22 plant we can use the ammonia coil for the new freezer room.

Basically can a pumped liquid evaporator be used as a DX evaporator on R22, by installing a TX valve?

Regards

[Sandro Baptista]

It's very risky despite the type of circuit it's not optimised for DX with the pumped evaporator you don't have liquid distributor so you can't guarantee that all coil is well feeded...some can be wet at the suction and others with much lack of refrigerant...and maybe the TX valve can't control very well the feeding at the inlet.

[McFranklin]

I know this is about three weeks late, but there is approximately a 20% capacity loss in a DX coil versus a coil with fully wetted circuits.
There are a lot of issues involved in changing over from R22 to NH3 in an existing facility. Typically you are not able to reuse much of the equipment.