Autocascade Build Thread (2006 Competition: Team Eshbach)

[eshbach]

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

[Cpt Twitchy]

You guys must really be into hygene. I have never brushed my teeth in the shop Looking good and cannot wait to see the outcome.

[eshbach]

We got a little bit more done this week, but not a whole lot.

The pictures are pretty self explanatory.

Here's the whole seperator contraption:



Here's how it looks in the system:



And here are the filter-driers:





The next thing on our plate is the suction line heat exchanger, and then we'll start putting everything together.

In the mean time, we've started 3 gallons of wine fermenting. We've got white grape rasberry, white grape peach, and pineapple.

[kayl]

good start to the auto, be interesting to see how it goes.
So ya a brewer as well hey, i like to brew beer, helps one while they work in the shed hey keeping ya warm.
that copper block pointing downwards is that the CPu heatsink?
I wrecon go with ethane and maybe a tad of ethylene
Is ethane expensive there?

[eshbach]

good start to the auto, be interesting to see how it goes.
So ya a brewer as well hey, i like to brew beer, helps one while they work in the shed hey keeping ya warm.
that copper block pointing downwards is that the CPu heatsink?
I wrecon go with ethane and maybe a tad of ethylene
Is ethane expensive there?

thanks kayl.

we don't actually have the cpu block yet. that's something we need to start working on at this point. we have a couple ideas for things that would be easy to make, but we don't have access to a mill or lathe so we're a little limited.

ethane is more expensive than ethylene here, but not much. and we can rent from the local gas company for $0.80 a day, so it doesn't cost us much to charge.

[kayl]

lucky bugger, ya know there is no limits on what cpu ppl can use, ie ppl can buy them and still enter
I can get ethylene cheap quiet cheap but ethane is through the roof

[GuGaCoSa]

looking very good liked your watercooled condenser.
close down the filter to not absorve moisture
can u send me a pm talking about wine fermenting?
thank ya

[eshbach]

just a quick update... we threw together a mini hx for the suction line. I think the ROI on a big hx would be pretty small since the second stage gas is already water cooled.

this is pretty much your basic tube-in-shell design:

[eshbach]

slowly making progress. suction line HX and main HX hooked up now:

[[XC] gomeler]

Looks good, I really need to step up and get started =\

[eshbach]

We put our evap together tonight. It's made out of that copper swiftech chipset cooler.

here's the heatsink (minus a few posts to make it fit correctly):



then here's the shell we made for it:



and here's the whole thing put together, with large diameter captube to be hooked to the CPEV:

[godmod]

i like your autoC, it doesnt look like all the others...

[eshbach]

well.

a lot of things have gone wrong here... mainly, the CPEV valve i was planning to use on the second stage got lost in shipping somewhere between poland and here, and the postal service has been unable to find it.

so, i thought, "ok, i'll use cap tube on the second stage, it's not that big a deal".

then, i find out that i have the wrong size flare nut for my TXV. will the local shop sell me just a flare nut? no.

so now, a system designed for 2 valves, has 2 cap tubes. great.

to make matters worse, all the vibration caused our water cooled condenser to spring a leak (in splendid fashion, spraying water all over everything).

i've dried it all out and sealed the leak, and it's working, i guess. i don't have the water cooled condenser on in these pictures because the patch won't be try for some time.

i will have real pictures with temperatures before midnight XS time tomorrow, i promise.

here are some shots of it working, in a completely broken no-phase-sep-condenser kind of way.

[eshbach]

well, here it is.

it turned out a little better than i thought it would with just cap tube.

i ended up using CO2 for this. I was going to use ethane, but it just didn't work out. the pressures are pretty high as it is.

i hacked off some cap tube after last night (first stage). pulled a vac and charged it up.

after the first charge i was only getting -59, and i was a little dissappointed. so, i just started playing around with it, and eventually i just saw the low side pressure drop like a brick and the temperature go with it. i was really trying for -85, but no matter how much i tuned it i couldn't get there. oh well.

here's the pics:

[eshbach]

load temps are in.

i'm using the 200W cartridge heater from McMaster. The load tester I made is kind of... ghetto. i thought i had a block of copper laying around, but i couldn't find it. all i could find was a copper rod and a bunch of pipe... so i improvised.

here's what i ended up with:





what i did was cut a piece of pipe about the length of the heating element, then cut a piece of rod about the same size. i flattened the pipe as best i could around the heater and then brazed it shut. then i brazed the rod onto the flat part of the tube.

i turned on the heater and let it get up to about 200 C (which happened very quickly) before i turned on the autocascade.



it took a little while, and i had to add some R22, but eventually the autocascade pulled it down below -50.



then i checked the temperature of the of the back side of the heating element. i figure this is a decent approximation of what the CPU die temperature would be:




So, I'd have to say I'm fairly satisified with how this came out. I definately think it would have been better if i could have used the TXV and the CPEV, but for something i had to throw together at the last minute, it honestly did better than i had expected.

[n00b 0f l337]

Awesome job for simple co2 and r22!

[Evil_Spork]

nice job!

oh hey look, my guages!

[eshbach]

nice job!

oh hey look, my guages!

i'd feel worse about having yours at my place if it weren't for the fact that you have mine