Dear all,

I'm hoping to put together an ultra-low temperature two-stage cascade system that can go down to -90 degrees C. I'm planning on running it routinely at -80 degrees C so just want the extra 10 degrees for tolerance!

Additionally, I need a system that supplies a cooling capacity of 200 W at -80 degrees, which equates to a cooling capacity of ~ 5 kW at 20 degrees.

At present, I think I need a two-stage cascade unit using R404A and R23 refrigerants. However, I don't know what size compressors are required. Can anyone give me an idea of how I could calculate that or if they have experience in this area?

I've heard that Danfoss compressors are well respected in this area?

I know that you can buy similar products that do the job. Julabo make a unit (FPW91-SL) that do the job but I don't need all of the control hardware that surrounds it - nor can I afford the price!

Thanks and look forward to your comments.