HX = Heat Exchanger
I use a plate design which has 2 chambers of Seperate alternating plates so that the gas is entirely separate.
The design I am using is based off of the use of 3 different gases.
Stage 1 will use straight r404 or r507 or r402 which are all relatively low pressure gases which can be condensed with relative ease using standard compressors and condensers.
Stage 2 will be using a gas called R170 or Ethane. Ethane is a high pressure gas which will condense using a standard compressor at temps in the range of -12c at 160psi. Obviously a standard fan cooled condenser is not going to be -12c or colder so I either need to increase my pressure to a very high level or make my condensing temp colder. So to do this I use my first stage to cool a plate heat exchanger by flooding 1/2 the plate heat exchanger with r507 and the other with r170. As the r507 boils off cooling my entire heat exchanger the temp drops to a very nice r170 condensing temp (target -30c under all load conditions). Same principal applies for the second stage heat exchanger where one side of the heat exchanger is cooled with r170 which boils off keeping my heat exchanger in the range of -65c to -88c or so under varrying load conditions.
This is good because I find that r14 likes to perform best between this range. Edited by Sdumper - 9/13/10 at 5:10pm
Just finished up the second stage expansion tank and will mount the stage one compressor tomorrow.
Also mounted the base to a reinforced platform so it can be rolled from room to room...
So much to do and so little time to do it in.