Choice Between These 2 Compressors?

[boshuter]

Which of these compressors would be best for a SS? The only factor is performance, noise is not an issue.

1. Danfoss 7.5b - I have 2 of these, afaik they are around 1/4 hp.

2. LG Rotary QA114CBD - Got one of these and it's brand new, can anyone tell me the approximate hp rating, or if it would be a better choice than the Danfoss (which would give best temps/capacity)?

Here is a link to the specs on the rotary; http://www.lge.com/products/component/compressor/aircon/download/r_QAseries/pdf/QA114C.pdf

[hatemi]

That rotary is like 2 times as powerfull as those danfoss compressors :D Are they FR 7.5b ?

[LukeXE]

this Rotary is probably 3/4HP, so I would use it, not Danfoss compressor ;)

[boshuter]

Yes they are FR 7.5B's. Thanks for the input, I figured the rotary would be a better choice, but wanted some feedback from more knowledgable people :toast:

Maybe you can answer another question... would it be benificial to put a SLHX in between the condensor and metering device? I've seen some pretty impressive results with a system like that. If yes, would a tube in tube hx work, and what sizes of tube would be best? (1/4" inside 3/8" or 1/4" inside 1/2")

[Xeon th MG Pony]

I'd say 1/2,, gives more mass flow becuas with the 1/4 in there it would pretty well equal a normal 3/8th in the end to a degree (I'm assuming you're talking about a subcooler unit here?)

[lma01]

"Motor input=743watts" from LG documentation; it might be nearly 1hp.

[epion2985]

heh hope this wont run 24/7, power bill might suck. Thats my only deal with powerfull compressors.

[boshuter]

heh hope this wont run 24/7, power bill might suck. Thats my only deal with powerfull compressors.

Nope.. it's for benching only ;) It has to cool my 950 Presler, so it's going to take a fairly powerful compressor. That is also why I asked about putting the SLHX subcooler between the condensor and metering device. Any opinions on that? Is it worth the trouble, will it run lower temps, how will it affect capacity?

Any suggestions on tubing size, length, etc. for the subcooler will be appreciated. BTW, I'll be using a Chilly1 evap on this system.:D

[hatemi]

The usefulness of SLHX kinda dapends on the refrigerant used. There are 2 designs that come to my mind that I would use.

First is using 5/8 tube on the 3/8 suction.
Second is wrapping 1/8 tube tightly around a piece of 3/8 tube and using soft solder to connect them.

[boshuter]

The usefulness of SLHX kinda dapends on the refrigerant used. There are 2 designs that come to my mind that I would use.

First is using 5/8 tube on the 3/8 suction.
Second is wrapping 1/8 tube tightly around a piece of 3/8 tube and using soft solder to connect them.

After doing some more research, I'm considering just scrapping the subcooler idea. I'm going to be limited to either propane or r22 for now, I don't think the slhx will help much with either of those. Maybe just a simple cap tube setup will be the best..;)

[hatemi]

Subcooling with cap tube is usually more than enough :)