frozen cascade

[kayl]

You didnt have to add any oil to that oil sep?

Yeah 400ml, I only added 300ml, I was even considering not adding any at oil, since there should be more than enough in the compressor. Mainly because the system this compressor would normally be installed in is so much bigger than the system I have it running in. What ya think Nol?

kayl:
I'm not unseen but I've been dealing quite alot with dual captube and I can say, you're right, the discharge pressure is slightly lower with dual cap compare to single, if thats good or not I don't know but the results is good and massflow as well.

Hey tim, that’s cool, I guess ya been playing dual cap lines with chillers maybe with some insider information?
Lower pressure istn so bad as long as the pressure is enough to condense the refrigerant at its liquid line temp. Ie I have seen 150psi when using r290 with cascades with a big condenser and a cold liquid line even at load But then in a 42c warm case that pressure rises to 200psi running for several hours at a time.

The question there is I just think your less restrictive. You could acheive the same thing with a shorter captube, but it would have to be quite shorter. A bad analysis of this might be, if your captube length would normally hold X watts, then two will hold 2X watts. In a sense we're doing the same thing as having dual evaporators, but only with one, and so we're creating double (give or take) the headroom.It is great though! If our actual evaporators were bigger I'd try dual captube to it, but I think a larger diameter line or simply a shorter line can take care of that.

I think of dual caplines as a bigger ID capillary line. My main goal is to deliver more liquid refrigerant to the HX and run a lower first stage Low side pressure with colder temps. With my last cascade I had the second stages liquid line leaving the HX at -35c feeding the cpu head.
I charged the cascade so first turn on 1st stage was down to temp in 3mins and second stage at -100c 2 mins later. So first stage doesn run that cold, but has lots of capacity and is flooded well. Result it only takes the cascade 5mins for total pull down to -100c. Havnt seen another cascade pull down that fast yet

One thing that I realized looking at it is... if the impact of dual cap tube actually is happening in more practical level than say, on equation level. While restriction as whole might be same, I am wondering if dual captube actually alleviates some resistance caused by oil flowing in circuit... It really shouldn't impact it too much but I am just wondering Lower discharge is usually good thing as long as you have enough to condense in different conditions through cap tubing designated

Im not really shore what will happen, but I imagine the lower discharge is as a result of less refrigerant backing up in the condenser. As you said though I hope the refrigerant condenses properly, time will tell.