condensor size?

[solo]

is there a certain condensor size that i should use with a baker block and r404a?

im looking at about 12ft of .026 cap tube

any recommendations?
also is there any place i can buy these online?

[Gary Lloyd]

What are you cooling? How many watts is the heat load?

[chilly1]

Temperature and compressor displacment?

[chilly1]

Is that an sc12mlx? and a baker block I would start with a 3000 btu condenser and a fan I could control. and about 11.5 ft of .026 captube /... this will get you in the ballpark.

[Gary Lloyd]

That cap tube sounds much too restrictive to me, even for the smallest load, and we don't know what the load is.

And 3000btu is 879watts, which seems like gross overkill.

But I could be wrong. :D

[chilly1]

That is the smallest condense rI would use on a 1/2 hp and then I would use a fan control that slows down after a few min.. But condensers are dependant on air flow.. And yes the cap tube is too restrictive but it is a place to start, I usually end up with 10 feet

[Gary Lloyd]

I'm thinking 10 feet of .026 is good for about 100W tops. Are you sure you don't mean .028?

And the condenser needs to match the load, not the compressor.

[Gary Lloyd]

On the other hand, he still hasn't told us what he is cooling. CPU, GPU, other? How many watts? We don't know what the load is, so how can we know what cap tube to use for that load?

[chilly1]

Exactly but I am thinking this is for a cpu cooler and I should have stated that..

[solo]

im cooling the CPU, heat load is around 150-170 watts, calculated using benchtest

should i use 0.026 or 0.028

[Gary Lloyd]

I would go with about 10 feet of .028, but others may disagree and understandably so. This is not an exact science, and the cap tube charts are not designed for lowest temperature, but rather for highest capacity.

[solo]

i only have access to 0.026

http://www.rparts.com/Catalog/Major_Components/condensers_&_evaporators/012-1001.htm

how is that condenser?

[solo]

gary, is that condenser proper?

[Gary Lloyd]

i only have access to 0.026

About 7 feet of .026 would be equivalent to 10 feet of .028.

[Gary Lloyd]

gary, is that condenser proper?

What condenser are you talking about?

[solo]

Originally posted by Gary Lloyd
What condenser are you talking about?

http://www.rparts.com/Catalog/Major...rs/012-1001.htm

that one

btw, 7 ft is the way to go then?
what kind of temps can i expect?

i dont have the ability to rebraze evrything and charge it up again, so this cap tube thing will be a one-time job

[Gary Lloyd]

The heat is dissipated not just by the condenser, but also by the airflow. The larger the condenser, the less airflow is needed, and vice versa. Given these two factors, we could recommend a great many combinations, and all would be correct.

With that small condenser, I would recommend more than the 90cfm fan they suggest, maybe something like 150cfm, in order to keep the delta-T (difference between air in and air out temps) below 10C. But yes, that would work.

[solo]

Originally posted by Gary Lloyd
The heat is dissipated not just by the condenser, but also by the airflow. The larger the condenser, the less airflow is needed, and vice versa. Given these two factors, we could recommend a great many combinations, and all would be correct.

With that small condenser, I would recommend more than the 90cfm fan they suggest, maybe something like 150cfm, in order to keep the delta-T (difference between air in and air out temps) below 10C. But yes, that would work.

i think i will grab one of those comair rotrons, maybe 2 with a push/pull config

235cfm maybe running at 1/2 speed

woot

http://img12.photobucket.com/albums/v31/solographik/yahoooo.jpg

sound good?

[Gary Lloyd]

I would go with 3/8 discharge line, and 1/4 liquid line from condenser to cap tube.

[Gary Lloyd]

That is the smallest condense rI would use on a 1/2 hp

Chilly... On a conventional system with its much larger cap tube, or a system with a modulating metering device, I would agree with you. But using these tiny cap tubes, which severely limit the flow, and given the very small refrigerant charge, I wouldn't expect to see any appreciable build up happening on startup, regardless of compressor size.

[solo]

Originally posted by Gary Lloyd
I would go with 3/8 discharge line, and 1/4 liquid line from condenser to cap tube.

isnt it the other way around, correct me if im mistaken

[Gary Lloyd]

No it isn't the other way around, and you are mistaken. :D

[solo]

O_O!

a 3/8" pipe doesn't fit in the discharge line

its a small pipe, a 1/4" pipe

[Gary Lloyd]

Then 1/4 will be fine.

[chilly1]

Originally posted by Gary Lloyd
Chilly... On a conventional system with its much larger cap tube, or a system with a modulating metering device, I would agree with you. But using these tiny cap tubes, which severely limit the flow, and given the very small refrigerant charge, I wouldn't expect to see any appreciable build up happening on startup, regardless of compressor size.
The condenser I specified earlier is rated at 150 cfm and 1/4 hp for a small single door beer cooler, (case parts smallest condenser) These have three rows and 7.5x 9 and are steel. This with a 50 cfm 12 vdc computer fan 4in gives me about 10degF TD on a sc12mlx compressor with a 150W load. The fan can be made larger if nessassary and then a spped control based on TD can be installed. The condenser is a little larger but will give the extra head room for better control at much quieter operation. Before I send these out I silversolder copperstubs on them for easy use, Steel to copper connections are hard to make correctly and my controlled atmosphere rig works well.