Freeze dryer, Ice condensor - Pipe dimension

[petter78]

Hi all,

I have been asked to offer a cooling system for a freeze dryer. The ice condensor itself will be designed by client.
But I will give them some advise regarding pipe sizing.

The system will be a R507A system with DX.
We aim for -60C in evaporation on coil.
The coil will be standard AISI 316 pipe bend to a number of hairpins. We will make several pieces in parallel to minimize pressure drop. Around 8 m a piece if possible.

But this gives quite a big pressure drop unless we go to a big pipe, around 1 1/8". Speed will be 15 m/s which seems ok.

Question is, how big a pipe do you think we can use and still have liquid touch entire surface of pipe?

Hope somebody has tried something similar and can come with some input.

Best regards,
Peter

[Rob White]

.

You say DX so the biggest problem you have there other than pressure drop is
the length off the single evaporator tube.

You need to make multiple passes, not one single pass.

If you had a header you could have three or four passes and that will help with
liquid surface contact inside the pipe.

Rob

.

[caileagany]

You need to make multiple passes for kayaks UAE, not one single pass.

[Brian_UK]

Are you allowed under FGas regulations to manufacturer a new R507 plant in the EU. I thought that was outlawed as of 1 January 2020.