View Full Version : Rotary CPU SS
new build comming since old compressor was damaged when arrived from factory :confused: , have cause a looong delay but now I'm back on track.
very limited time schedule since I'm aiming for bringing it with em tomorrow to dreamhack
started earlier today @ 4pm, and little bit after 6pm I was finished with all brazing and I put some nitrogen in the system for pressuretest. almost 19bar in system now and it has been in there for more then 3H now, seems to be leakfree but I will let it stay atleast til tomorrow morning to make sure it's ok :up:
parts used:
17k btu rotary
luve 194 condenser (1,94kw capacity with 15K delta)
LD evap + 1.5m flexhose
LD case (came with damaged paint, they are sandblasted and repainted)
315cm 0,8mm captube
small slhx ~50cm 15/6mm (stole that idea from piotrs' incredible -62rotary SS :up: )
gas: r507/r410
I'm aiming for simular temps as piotr since we have simular stuff. If I had r23 I would made an autocascade out of it and hit the -70*c during 250w load but I don't have it and dunno where to get it for decent price... well let the pictures speak. I havn't clean it or bolted the compressor yet since i'm soaping joints and checking for leaks. the mess will be solved later.
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0104.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0105.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0106.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0107.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0108.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0109.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0110.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0111.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0112.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0113.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0114.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0115.JPG
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0116.JPG
n00b 0f l337
11-30-2007, 01:20 PM
Looks nice, good job!
Duniek
11-30-2007, 01:38 PM
3,15meters of 0,8mm captube ??
:confused:
yes, i had 2.8m on my dual headed which hold 455w load.
think 3.15m will be a good start for single head since I'm aiming for low vac ( ~0,5bar) and I still need to be able to condens r507/r410 proper.
boshuter
11-30-2007, 05:32 PM
Nice job :up:
I'm doing one similar but just using either 507a or maybe some 502 I have left, just looking for good capacity with decent temps for a benching system.
Do you have your hoses hooked up backwards, or are they reverse colors in Sweden?
backwards.. my mistake ;) this was before I pressuretested.. just putted flow from hi to low side to make sure captube was not blocked when soldered to drier. now both sides is hooked up and everything is pressuretested
but I have notice something strange;
tempereture have decrease a couple of degrees during the pressuretest and pressure have drop from 18.8 (after 30min equilizing) to 18.6 in 6-7H, dunno if it's cause of a leak or temp.. I'm not sure yet..
time will tell.. but I havn't notice any leak when I have use soap on all joints... evap+flex is pressuretested 48H alone before brazing everything together and it's leakfree. if pressure is still dropping even if temp is constant I have no idea whats leaking.. hopefully it's a joint and not the new condenser.
boshuter
11-30-2007, 06:47 PM
I've chased leaks like that and a lot of times it turned out to be where the hoses were screwed onto the access valves, also it sometimes takes quite a while before the pressure stabilizes.
yes i know, and that's why I'm not to worried. well now it have been same pressure 18.6bar since yesterday~~6pm and tmep have been the same since.
It's fully insulated and I'm vacuuming now :)
jinu117
12-01-2007, 05:09 AM
Something I do to put few things out of this situation :)
Grab qucik coupler type for hose (or ball valve one)
Pressurize it till every thing balances. Disconnect, close the cap tightly around for valves. Mark the PSI. Few days later, precharge hose with nitrogen for same pressure and connect it up. You will see if there is any difference... :)
nice work tim, i like the fan at the back of the case
jinu:
I use quick couplers. and I didn't use manifold when pressuretest. I have another "box" for that.. a wooden box with reliefvalves (2*24bar if I remember right), big manometer graded up to to 30bar and 2 ballvalves, one for nitrogen and one for refrigerant (for leaksearch, small shot of refrigerant, rest nitrogen)... but I agree, better to disconnect everything if possible.. but now I didn't.. but it was stabale ~20H @ 18.6bar which is leakfree for me since evap+flex+captube was tested 48H before brazing everything else together.. I'm 100% sure this is leakfree.
we will see.. still vacuuming and will make a first run tonight, aiming for -60 @ 225-230w load.
kayl:
it's justa fan mesh to let the air out, but I agree, it's nice. to sad the front mesh isn't big enough to fit the condenser tight to the front. have left 50mm between front and condenser to get proper airflow into whole condenser. Picture of unit in case tonight.
regards
Tim
jinu117
12-01-2007, 06:36 AM
:) Looking forward to it... -60 at that load eh? Lofty goal for sure... :)
piotr reached -62 @225w load, so why wouldn't I do that too? :p
picture of fully insulated and unit hooked up with manifold for vacuuming.. http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0118.jpg
n00b 0f l337
12-01-2007, 07:40 AM
Nice setup even tho if I do say it, the vacuum pump looks a bit out of place ;)
what do you maen with that n0l?
Planet
12-01-2007, 09:14 AM
Looks like a smiley face on the vaccum pump? Idk just kinda looks weird is all he is saying.
yup, the vac pump is a funny dude :p
btw.. I have problems with pressures.. dunno why, but I'm filling it and filling it and now it runs with 11/0,6 with 3,15m of 0,8mm captube.. Don't know what to do honestly, with those pressures the refrigerant won't condense, strange though. I'm thinking of remove the slhx to get the higher pressure. I'm not sure what to do.. havn't got such problems before... can it be this model of compressor that doesn't like to run in those conditions? (it's a r410 compressor)
regards
Tim
Superheat and Subcooling?
k, good luck with the temps your aiming for.
3.2m capillary line is quiet long, short is also good with rotaries.
piotres
12-02-2007, 06:16 AM
Nice :D
IMO too long captube ...but we'll see :up: .
I've also noticed 0.2 bara pressure drops in first 24 hours ...so that's normal IMO ;) .
good luck :up:
Regards
Peter
yes I assume so too. but now it's leakfree.. and I will trim the captube.. to long as you said. proberbly more like 2.5meter in the end just as on nl11f units :p
my biggest issue atm is that I can't get hi side pressure to gain, I don't get above 11-11.5bar on hi side and low is -0,4 (I was typing 0,6, but that was bara. strange problem, considering compressore replacement or something.. I've heard on extremeoverclocking about sneil who had problems with compressor even if it gave decent idle temps..
jinu117
12-02-2007, 07:30 AM
Well it's quite simple... I said this earlier somewhere... you don't get enough gas back in than there is nothing for compressor to compress.
Clemmaster
12-02-2007, 10:13 AM
What's ambiant temperature?
Even If the suction mass flow is tiny the dischage pressure should increase until condensation
if you insulate well I don't think the ambient temperature would make much of a difference
I think his biggest issue is having the cap tube be too long, but I'm no expert
jinu117
12-02-2007, 11:00 AM
I hope Darrell doesn't mind me posting it here but enjoy...
http://www.udarrell.com/ac-trouble-shooting-chart.html
What's ambiant temperature?
Even If the suction mass flow is tiny the dischage pressure should increase until condensation
20-21*C stable room temp.
if you insulate well I don't think the ambient temperature would make much of a difference
I think his biggest issue is having the cap tube be too long, but I'm no expert
maybe, I will shorten it to ~2.6m
I hope Darrell doesn't mind me posting it here but enjoy...
http://www.udarrell.com/ac-trouble-shooting-chart.html
will have to take a look at it. we will see.. going to shorten captube first and make a testrun and see if I measure any difference.
regards
Tim
Well it's quite simple... I said this earlier somewhere... you don't get enough gas back in than there is nothing for compressor to compress.
I agree with jin, this is why i said your capillary line was too long. Long capillary line ensures that the refrigerant condenses well, but unless your using a really high pressure gas you wont get much flow through the system.
Shorten the capillary line will increase the head pressure. If you go too short though you will get too high head pressure as too much gas passes down the capillary line, 2.7 to 2.5m will work well with rotaries specially with an accumulator. YOu will also find that you need it tadf shorter than normal to run vacuum easier and get the temps your looking for :yepp:
yep I think so to, I will try with the shorter captube anyway.. don't have much to loose, I have 2mm captube (id) brazed ~50mm on evap to make easy captube swap (no need to heat up evap for captube replacement)..
I must say I'm really noob on captube, hate it.
I put the recovery unit on earlier tonight and I've recover all gas I want to recover... tomorrow I will cut down to 2.6m and vacuuming it... results comes tomorrow...
thx all for the input.. as i said.. noob on captube :( in commersial use we always use expansion valves.. which means we just need to change ortifie depending on coolingcapacity needed.
jinu117
12-03-2007, 08:09 AM
Very good Tim. Always good idea to do such when you have new parts in use. BTW, I just realized something, R410A compressors are actually smaller in displacement than say, R22 compressor given same HP rating as well. You see, the HP rating goes by amount of cooling it can do and since R410a has higher efficiency in given application (high temp cooling), what they do is make it smaller to match now a days on displacement part of story. In fact, 5 HP condensing unit is not same 5 HP condensing unit it used to be now a days. With more efficient evap design, sophispicated control logics and more stringent operating range, it will do same job with proper installation as previous 5hp unit. (System installation has became more critical in last few years)
Have you looked at compressor spec and compared with corresponding R-22 unit?
Clemmaster
12-03-2007, 09:33 AM
HP rating is power consumption under rating conditions, not cooling capacity. Considering a given compressor, if you work with R12 or R22 you won't have the same power consumption @ their respective rating point : the HP rating will be different but that's the same compressor anyway.
interesting jinu.. have to take a look into it, but first I have to solve this captube problem I got on the unit, if the compressor is able to hold decent load with low suction pressure or not. I need to get the pressures right before doing anything else. 11/-0,4 isn't acceptable and the more charge doesn't affect anything else then the suction pressure is everything that went up, I think it's cause it's getting to much refrigerant condensed.. to small massflow. proberbly caused by the long captube and/or oversized condenser? but i don't think so.. ~1.3kw from compressor (max power consumed) and 250w from evap ? 1.55kw totally, 400w extra cooling capacity. well we will see whats happening. if it isn't possible to get decent ss temps I think autocascading is the only way...
sorry for double posting...
I've shorten the captube a second time now and i've got it start now :)
http://www.phasechange.se/photos/units/malmedahlsSS/DSCN0143.jpg
now I get decent discharge pressure (12.5bar) and about -0,5 on suction, -65 as lowest idle with this charge. I started without loadtester to make sure the K-probes was mounted decent on the inside of insulation.
strange thing thought, shorter captube = higher discharge but same suction.
boshuter
12-07-2007, 02:29 PM
Looking much better tim- :yepp:
How long is your captube now?
I had to shelve my rotary unit to finish another build for a customer, I'll probably get back to it next week. I'm thinking about taking the small accumulator off mine, shortening the cap tube, and adding a SLHX to try to solve my problems.
I have 2.4-2.5m of captube now.
strange thing. i was filling it (without load) to reach -63*c idle, and then i shut it off and let it stay for maybe 30min, fire it up again and the low side doesn't get below 0,8bar(a) and doesn't reach below -50*c during idle, load temp is about -45*c with 250w. I think this can have to do with the slhx position.
my slhx ends in same height as the top of condenser, think that cause atleast a part of the problem. will put the slhx flat in the bottom (same height as condenser outlet) to see whats happening, I think it will solve the issue. not sure yet since i havn't play with this to much, but will put it flat and try tomorrow, it's worth a try atleast..
but what's boughtering me is that the suction pressure was 0,5bar(a) when i shut it of after filling, and when booting it up again it didn't get below 0,8bar(a). thats strange thought. one thing is atleast good, the captube seems to be correct length and condenser outlet was just 25-26*c after 1H with 22-23*c roomtemp. 2kw condenser seems to be well sized :up: