DBlue135 and I recently got started on our autocascade for the competition.

We're using a 1/2 hp rotary compressor, R22, a fairly standard condenser, a home-built water-cooled condenser/phase seperator, and a TXV on the first stage

The second stage will be pretty standard, either Ethane or Ethylene and a CPEV.

Both stages will return through a slhx and we plan to use a pretty large expansion tank.

We've made pretty good progress so far. The first thing we did was build the main heat exchanger. It's on the small side, so if we run in to capacity issues this will be the first thing to go. We soldered the layers together for no real reason. It might help with heat transfer a little bit.



Then we made the coils for our water-cooled condenser. These are 3/8" copper pipe and DBlue tells me it was not very fun to bend these:



We then put the coils together and added their inlet:



Then came the first version of our main seperator, which looked like this:



We decided the volume was too low so we rebuilt it. We also constructed the housing for the water-cooled section:



We picked up a cheap base board and gave a it a coat of blue spray paint. It's big enough that we don't have to be too careful with our layout, there's a lot of space. We mounted the board on casters and mounted the first few components to the board:





We went to johnstone and they helped us decide on the best TXV for our application. What we came away with the danfoss TX2. This is my first try with a TXV, but i'm hoping it will be good for this type of system since it should get the first stage down to temperature quicker than a capillary system.



And most recently we mounted our water cooled condenser and base to the board. We should have the first stange done next weekend and then the real fun will begin