Suggestions Please?

[clipperjay]

I've been out of the Phase play for awhile too many comitments with job and family.

Recently I decided to use the scrap in the garage and found a BD50 danfoss1/4hp that uses R134a my rig is to reach 15C loaded NOT sub zero as I'm using 12V battery to just power the thing averaging 6 amps LOL!
I got temps from Load of 45C to 20C which is really poor, but thinking that a special blend might be needed I've heard R402a or 170 can be used?
I need some blend percentages to try as I know my usual R404A blends will just knacker out the compressor.

Specs:
Danfoss BD50
Captube 0.31" 2 meters sounds short but this has been tweaked to optimium length for my usage.
Dryer grey blob LOL
Two 120mm X 38mm panofans 65CFM X2 one sucking and one blowing on 12V
The condenser is about H180mmX L190mmX W70mm.
Evap undisclosed as its not a normal evap.
Unloaded temps -10C
Ambient 17C

Hope some usual suspects can lend me a hand:up:

Edit: In the right section now LOL

[HoriWanderFuLL]

why would it only be getting -10c unloaded temps for ???

it should go as low as -35c unloaded temps ...

as for blends in that little compressor it could give it a starting problem or stress the compressor to much...

Im sure somonew will put u on the right track cheers

[clipperjay]

why would it only be getting -10c unloaded temps for ???

it should go as low as -35c unloaded temps ...

as for blends in that little compressor it could give it a starting problem or stress the compressor to much...

Im sure somonew will put u on the right track cheers
Thanks Hori
Well the evap is not on one spot the application is unique so -10 is not too bad on the rig I've made, just on R134a. I've taken it as far as I can physically, but need to get a R404a & R134a blend.
Drew has suggested using a 30-70% split on the R134a and R404a, but untill I start testing a pre blend I can't tell what the pressure is going to be like?

My plans are to pre blend the two liquids first into a propane bottle then charge it from that around total 500g of liquid weight.

I know there are some people here who have blended and have some idea of how the two gases react in a low presure system. I thought saving time by using the experienced bunch on here, or give me an indication which other gases were better suited to the BD50 Danfoss compressor?

Cheers
:up: Jay

[[XC] 2long4u]

I have a few questions. What are your pressures? 2 meters is about 6 ft right? What is your heat load, and unique application?

[DetroitAC]

It's not working well, so blending gases should fix it? :rofl:

BD50 is a very tiny compressor, you may have too small a compressor, too much load, wrong captube length, wrong charge, pipes hooked up backwards, air in the system, etc, etc.

Hard to tell anything at all with what you've posted so far.

<another sarcastic comment deleted here>

[tim-]

I've tried those compressors, they are hard to get anything good out of.. maybe chipset cooler, but not much more.. sorry to say but that's true.

[clipperjay]

I have a few questions. What are your pressures? 2 meters is about 6 ft right? What is your heat load, and unique application?
Low didn't record but within normal running spec from R134a
2 metres yes bang on as anything longer didn't frost up turned into gas before delivery to evap.
The heat load is only about 60C I've got it down to 20C on load so not bad.
Can't coment but takes a hell of a lot of liquid!

LOL you can coment as much as you like, as I stated I'm not into this for Subzero temps! It's a BD50 on 12V I think I know what I'm doing!:rofl:
I've already got a DD that goes down to -76C and built cascades.
So cuming back to the question on blends anyone with the mojo out there?

Tim yes it far more of a challenge to use waste bits to build a subzero project on limited specs its what drive us I guess.

Ron are you about the website was out for a while?
Jay

Edit: By the way with conventional evap and systems I can get to -35C on a BD50!

[DetroitAC]

Jay, I'm not judging you for using such a compressor, but the point I was trying to make is WHAT'S THE LOAD? How many watts are you trying to remove? The first and most basic step in sizing a system is figuring out how much heat you need to move.



The heat load is only about 60C I've got it down to 20C on load so not bad.

60C doesn't indicate load. Imagine a truck driver complaining about poor performance up a hill, mechanic asks "How much load are you hauling?" Truck driver replies "chicken".

How much is what matters, half order of McNuggets, 20 tons, how much?

[Duh]

J

60C doesn't indicate load. Imagine a truck driver complaining about poor performance up a hill, mechanic asks "How much load are you hauling?" Truck driver replies "chicken".

How much is what matters, half order of McNuggets, 20 tons, how much?

:rofl: man you really made me laugh...

[wdrzal]

"How much load are you hauling?" Truck driver replies "chicken".


Do you know if the truck was full of 1000 pounds of live chickens and total truck weight was 10,000 pounds .Then all the chickens started to fly inside the boxed truck at the same time, the truck would still weigh 10,000 pounds;)

[[XC] Lead Head]

"How much load are you hauling?" Truck driver replies "chicken".


Do you know if the truck was full of 1000 pounds of live chickens and total truck weight was 10,000 pounds .Then all the chickens started to fly inside the boxed truck at the same time, the truck would still weigh 10,000 pounds;)

Yup, saw that mythbusters episode:D

[Ssilencer]

I thought the truck left the route flying to Graceland.

[the_new_guy]

Lead Head;2221831']Yup, saw that mythbusters episode:D

yaa, mythbusters rocks.

[clipperjay]

To give you a constant wattage load in heat it means I must have a fixed temperature sensor? I don't! The only fixed variable I have is airflow @60C thats all I can give you.
It's fine guys I'll start with a 15&#37; blend then work my way up and cross reference with the PT charts to see whats happening in the system or try anyways!

Did the truck have Helium in the tyres though?

[[XC] 2long4u]

2 metres yes bang on as anything longer didn't frost up turned into gas before delivery to evap

It wouldn't turn to gas if it was soldered to the suction line. And you have no way of measuring high and low pressures?

[clipperjay]

It wouldn't turn to gas if it was soldered to the suction line. And you have no way of measuring high and low pressures?

The system was saturated with heat in terms of ambient I started with 3meters and realised the liquid was nice and cold up to 2metres, so on that bases anything past it became vapour/gas or boiling off too quickly.
I do have some gauge's just didn't record as I was charging it domestically i.e. not accurate enough first couple of runs into tweaking it they were lowish after discharging some of the gas. The proper way is to vac two propane bottles so I don't have any liquid or gas in the lines & gauges when charging and discharging then record the two combined weights on what went in and what went out, just being lazy until I experiment with exact proportions of blends and then take it from there. My brazing isn't to bad?
I haven't even PTFA the suction line or cap tube yet! LOL :)

Jay

[[XC] 2long4u]

The liquid in the captube shouldnt be cold. It dosnt get cold until it expands. As far as the liquid boiling off in the captube, I dont even think that is possible, unless the low side pressure is to high. And if you have a problem with there not being liquid then your condenser is too small, or not enough charge thats why I asked for pressures.

[clipperjay]

The liquid in the captube shouldnt be cold. It dosnt get cold until it expands. As far as the liquid boiling off in the captube, I dont even think that is possible, unless the low side pressure is to high. And if you have a problem with there not being liquid then your condenser is too small, or not enough charge thats why I asked for pressures.

Well when I mean cold, I mean I know the difference between ambient and liquid refriderant temps. This was done at charge the condenser is fine more than able to handle the loads.

[HoriWanderFuLL]

The Bd50 compressor evap head would be reading 0c with 160 watt heatload .with R134a gas

or -30c with 0 watt heatload... This is on a Vapo pe unit anyway....

changing from the r134a gas would only stress and kill the unit fast..the 12v mdule at the back of the compressor will probably burn out as well.they get bloody hot...

The blended gases work better with the Bd35 compressor R404

From the Asetek site ...
ALL users with a BD35F compressor (SE/Classic) can turn it into a VapoChill Xtreme Edition (The XE is based on a BD35F) by visiting an A/C workshop and tell them to evacuate the system and refill it with 70 grams of R404a.

The zero load temperature should be around -35'C. IF you charge it with too much, the compressor will not start as the working pressure inside the compressor with R404a is higher.

ALL users with a BD50F compressor (PE) can also fill their system with R404a, BUT as the BD50F uses the same (small)engine as the BD35F but have a bigger cylinder volume, starting problems can occur, why this mod is taking a chance (can of course be re filled with R134a again if it fails).

However we've done some tests on a BD50F with pretty remarkable results. We haven't found an exact amount of charge but it's around 60 grams of R404a. If you go for this you should tell the tech to charge it with a 0W load at -46'C (!). Our tests showed that it could remove 100W at -30'C. We haven't tested how much it can remove in total.

Full link might help you..http://forum.vapochill.com/showthread.php?threadid=3283

Cheers Hori

[Xeon th MG Pony]

why waste such a usefull compressor! Make your self a nice camp fridge or cabin fridge! or a 12V back up deep freezer! or put it in the clasifieds with the shipping info to Canada ;)