Second Attempt: r290 DD

[[XC] gomeler]

This is my second attempt at making a direct die vapor phase change cooler, I made a terrible mistake with the first one in positioning the condensor, attempting to force the propane to condense and flow against gravity But that is ok, I sat down and actually planned this one and only made 1 mistake, let me know if you guys have any suggestions.

Compressor: r22 by Americold 6.7 FLA 35 LRA
Condenser: 13 rows, 2 deep. 14"x14" or so.
Cap Tubing: .031 X 10 feet. (my mistake)
Evaporator: 3 copper endcaps, 2" for base, 1.5" for cover, 1" inside. The two smaller ones were placed against the larger one. The 1" has 2 holes drilled into it with the captube ending inside, and the 1.5" has a hole in the top to feed the cap tube and for the suction line.

Here are 2 pictures of the evap.
Inner cap
Finished evap

More Pictures
Finished Setup
Finished Setup-2

I ran this thing twice, once while outside in the sunken basketball court with no wind and temperature of 98* F. With these temperatures, these are the temps and pressures
Low Pressure
High Pressure
Suction Line
Temp

I was very dissapointed with these temperatures, this was the lowest I could manage to tune it to, I was thinking that my captube was limiting me, no matter how much gas I vented and how low the vacuum was, it wasn't getting any lower. So I settled with -40.4*C, which it actually settled at and I forgot to take a picture of. Then I dragged it back to my room, grabbed soem dinner, and cranked it up again.

Round 2-Room temperature 73.2*F
Unit Setup
Vacuum
High Side
Temp Reading 1
Temp Reading 2

Now when I was outside I had no fan and the temperature on the condensor was around 130*F. Back in my room with a 12" fan blowing over the condensor, the temperature dropped to around 80*F. The pressures also dropped about 30PSI on the high side, and it dropped into about 20" of vacuum. I know the thermometer is cheap and not reliable, but I am pretty certain that it is accurate within 10* celsius, and it stopped reading at -50*C, so I'm going to pretend I hit somewhere around -50*C. Let me know what you guys think, my only mistake was with the captube, I thought I had bought .028 and then I managed to accidently melt the captube at the t-connection =\ Otherwise, I am very happy and I can't wait to put it under load. Let me know if you see something I should be concerned with. So far the compressor isn't having any problems with the heavy vacuum, but I remember reading that it coudl cause damage, should I put a few shots of r290 into it to pull it out of vacuum a bit? This thing is beefy and I am hoping it'll have a decent capacity.

[Carlz0r]

Have you had it insulated while checking temps? If not, insulate it and try again. Without insulation, you're getting a MUCH higher load on it.

[[XC] gomeler]

Good point, I need to go buy some insulation, I don't think syran wrap counts as insulation. Time to find a source of insulation.