Mother of all Cascades, -100ºc Dual Evap that Cools the Motherboard also!!

[Unknown_road]

well this is the reason why most people start with single stage systems, your in over your head now. If you want help, give a complete list of pressures en temps.

btw when your low stage compressors aren't running their isn't much load applied to the high stage. So 2nd idea is useless. although I already warned you when you started on your project that the high stage might be to small @ teampuss. You want to call danfoss about it? WHY? they have all their compressor specs online.

Try adjusting the superheat screws on your TXV's for starters.

[Juicy629]

i cant wait to see how its going to move this thing.. =P

[gkiing]

well this is the reason why most people start with single stage systems, your in over your head now. If you want help, give a complete list of pressures en temps.

btw when your low stage compressors aren't running their isn't much load applied to the high stage. So 2nd idea is useless. although I already warned you when you started on your project that the high stage might be to small @ teampuss. You want to call danfoss about it? WHY? they have all their compressor specs online.

Try adjusting the superheat screws on your TXV's for starters.

Hey.. no need to be so critical

Very nice work corvette, I'm sure you'l get all the kinks worked out, especially with some help from the experts.

[faruquehabib]

damn, i just spent the last hour reading this thread...amazing. the most extreme project i have ever seen...

[IYP]

very nice.....we want more frost.....great work man....i am absolutly loving it

[ZeroX]

Impressive job!_!

I hope u resolve all the problems, and run that beast to get some results

Keep up the good work

Regards

[Waus-mod]

Well its matter of time i think... its a great learning progress!
Hope you can fix it

[berkut]

DO not play with the superheat setting on the TXV's.

Try adjusting your sensing bulb position first. If the line placement comming out of the txv's bulb is positioned asimetrical (closer to one of the sides) it should be placed in such a way where the side wherethe cap tube is should be pointing upwards. ... really hard to tell when im tired

Danfoss compressors are preety powerfull, i think they shouldnt cause any problems.

My cascade works on Danfoss compressors and i use a ALCO TI-HW txv... (designed for R22 but im runing on R507- try to finetune that!)

Please post a full list of pressures / temps

[extremecorvette]

looking good, but its starting to get crammed up in there.

I know, and I still have to find a place for your guyes controller to go

[extremecorvette]

What is the sucktion side pressure ?

Were the bulbs and TXV's insulated ?

You should fill the system with the bottle upside down

suction line was at 4 psi

The bulbs were insulated but the TXV's were not.

The system was filled with the bottle upside down but I turned it right side up for the pictures

[extremecorvette]

Berkut is correct on the bulb placement. Critical to how the valve will respond.

Liquid charge is also correct, we see the bottle upright in the pic. If you filled the system with the bottle upright the gas in the bottle would now be considered fractionated?? Im not positive about 402a though.

I insulate the bulbs and vavle on my cascades.

Ok, you have two stages cooled by one. I built this config and tested. I would suggest per my observations (correct me in I am wrong) you should set the first stage around 20 psi @ -40c for the first stage maximum capacity to NOT dip when second stage is under full load. I would avoid going into a vacuum on the first stage.

I forgot to say my suction line pressure was 4 psi and I still was only at -22c

[extremecorvette]

i found one.

the bulp must be placed on top of the tube, if there is oil in the tupe the valve will respond different.

<a href="http://img123.imageshack.us/my.php?image=bulb9ps.jpg" target="_blank"><img src="http://img123.imageshack.us/img123/2594/bulb9ps.th.jpg" border="0" alt="Free Image Hosting at www.ImageShack.us" /></a>

That was something I was thinking about last night at the Iowa State vs. Illinois State football game. I going to move the bulbs to the top if that doesn't work then the side. What do I have to loss.

[extremecorvette]

well this is the reason why most people start with single stage systems, your in over your head now. If you want help, give a complete list of pressures en temps.

btw when your low stage compressors aren't running their isn't much load applied to the high stage. So 2nd idea is useless. although I already warned you when you started on your project that the high stage might be to small @ teampuss. You want to call danfoss about it? WHY? they have all their compressor specs online.

Try adjusting the superheat screws on your TXV's for starters.

I have the specs on all the compressors but the specs only go down to -10c, I need them to go to -50c

Chilly1 has been a huge help on this project and has used Danfoss SC12MLX's before and had no problems. This on is a SC18MLX so it's bigger and should be able to carry the load, but I want to just double check any ways

[berkut]

Im asking again - how does the I stage refrigerant flow through the HX - downwards or upwards

This might be the key to your problems, i had a problem like that a long time ago, the refirgerant just flashed through the hx and had no cooling at all...

[Nosfer@tu]

RESPECTA.

Hope you geet the problems sorted out with your beloved rig.

So nicely don sir...

[placebo]

I have the specs on all the compressors but the specs only go down to -10c, I need them to go to -50c

try to call tecumseh about that issue and they will hang up the phone... you will just hear the *click*... lol

hope you got the right contact at danfoss...

[chilly1]

How is it going now?
THe bulb needs to be at 10:00 or 2:00 on the pipe/ the pipe needs to be level. Superheat needs to be between 10 and 20F the higher the super heat teh less refrigerant flow through the evaporator. THe inslt of the evaporator needs to be at the bottom the outlet at the top, oppisite for the condenser. R404 or R 402 needs to bye liquid charged only. Gas charging only will upset teh balance the the high pressure component of the gas will be the primary component inthe system and will cause head pressure and evaporator pressure to be high. From the discussions I have had with EC the suction rises to 50 psi with the bulb at room temp and wiht the bulp atached to teh suction line the suction pressure is 4 psi and the super heat is at 40 F.
So it looks to me that the valves are trying to run at 40deg superheat. In other words the heads have too little pressure in them to balance the 4 psi suction. WE need to change teh charge in teh bulbs to a charge like a Z or ZP,.. Or some other charge that will allow higher pressures or larger flows . IT may be that we need a 25CC compressor on teh first stage FOr larger flow rates..

[pythagoras]

As a temporary measure how about putting some heat on those bulbs to see if thats the problem? Hot air or resistive heat?

Regards

John,

[EMC2]

I have the specs on all the compressors but the specs only go down to -10c, I need them to go to -50c

Chilly1 has been a huge help on this project and has used Danfoss SC12MLX's before and had no problems. This on is a SC18MLX so it's bigger and should be able to carry the load, but I want to just double check any ways

Look at your spec sheet again... the -10 is in Farenheit, which is -23.2C

For an approximate capacity, look at the SC18CLX2, which is a 220V LBP version of the same base compressor At -40C it's 306W, -45C it's 194W, EN 12900 rating method (225W @ -45C ASHRAE LBP rated).

You can use Excel to do a curve fit on the provided data as well to get an approximate value at a lower temp.

Other comment, in LBP ssetups those compressors are rated with 3m/s airflow over the compressor.

You will get it sorted out bro, hang in there

Peace

[extremecorvette]

Im asking again - how does the I stage refrigerant flow through the HX - downwards or upwards

This might be the key to your problems, i had a problem like that a long time ago, the refirgerant just flashed through the hx and had no cooling at all...

Sorry I've been gone, it flow upwards

[extremecorvette]

Also found a bad TXV valve, so we had two things working ageist us. I'm changed from 402a to ISCEON 89

[kayl]

good luck.
i like the way ya attacked the insulation.
no electrical tape for this cascade.

[stockhatch]

Happy troubleshooting and good luck Can't wait to see this sucker working at 100%

[GoThr3k]

keep up the good work

[extremecorvette]

10th Update 9-8-05

Made a few changes to the system. I added a slight glass, and pressure tap.



And I switched from R402a to ISCEON 89



This is Darin Stoll, he has been a huge help to me. Some of you wanted to see how big it was next to a person. Here you go





That's the line that feeds the TXV's, I think my sub-cooling is good



I can get one Flatplat HX down to temp but not the other.



With out a load I would like to hit -50ºC to -60ºC on both HX