SLHX on Single Stage

[[XC] gomeler]

I've been thinking about ways that I could effectively prevent liquid floodback on a quad-core charged system without wasting the precious liquid that has been compressed and cooled by dropping it into a large accumulator. I am wondering if you guys think this would be a good idea, I figure it can't hurt and it might help load temperatures slightly.

Make a coil of copper similar to a desuperheater and place this coil between the suction line and the suction port on the compressor. Layer the coilers horizontally so that the liquid/gas will enter from the top and circle down with gravity/suction to the bottom and end at the suction port. Now wrap the capillary line around this little desuperheater forming tight coils and then solder the entire mess together and insulate. I figured that if you charge a system for optimal load temperatures that under idle you'll experience a wave of liquid as the evap load will drop from 200+ watts to 80-100 watts. The added benefit would be that the refrigerant would be chilled down to roughly evap temperatures therefore keeping it from having to absorb some of it's own heat as it evaporatores, therefore leaving the majority of the liquid to evaporate and whisk away evap heat.

So, good precaution/performance additive or waste of copper? I won't be able to test my concept for another week or more as I wait for various parts to arrive but I am curious if anyone else has done this in the past. If it is dumb then please be kind

[n00b 0f l337]

It can help indeed, thats sorta what we do when we wrap the capillary.

[[XC] gomeler]

Yeah that's what I figured, just wanted to take it to the next step and create the loops to impede the liquid from flooding back before it could be evaporated off. Guess I'll give it a try with the next build.

[n00b 0f l337]

Make sure the filter stays warm though.

[[XC] gomeler]

Shouldn't have an issue with that, filter is placed before the captube, there will be roughly a foot of captube between the SLHX and the filter and I can't imagine the cold seeping that far. I'll post up some results once I have the system built.

[wdrzal]

any drop of liquid refrigerant that leaves the evap does no good at all,as far as cooling evporator. If your under full load and boiling liquid in the suction line your either;over charged,or Too high high mass flow. But you can use the"extra" refrigerant/vapor to cool compressor as long as the condensor can reject the total heat load.but in the process of boiling off the liquid refrigerant in the suction line/accumalator you increase sucton pressure,thus increasing temperatures.

[[XC] gomeler]

True I understand that, but what about the huge differences between idle and load, being nearly 150 watts different? That is what I am trying to combat, not trying to improve load temperatures. A system charged to hold a load will act overcharged in an idle state, correct? I notice this behaviour with my smalle runits, I can imagine this is even more pronounced on quad-core tuned systems.

[Brettbeck]

The smaller or less copper tube you use on the low side will in turn lower the suction pressure. So if you plan on making a coil with copper tube (for low side), I would try not to make it too long.

[[XC] gomeler]

I'm thinking 4 turns around a mapp cylinder will do the trick, not worried about suction pressures as that'll be solved during final load tuning and I could care less about the idle temps.

[n00b 0f l337]

Well your suction pressures are definitly going to be higher with an SLHX, as you have a larger heat dump onto your suction.

[wdrzal]

Originally Posted by gomeler

True I understand that, but what about the huge differences between idle and load, being nearly 150 watts different? That is what I am trying to combat, not trying to improve load temperatures. A system charged to hold a load will act overcharged in an idle state, correct? I notice this behaviour with my smalle runits, I can imagine this is even more pronounced on quad-core tuned systems.

150w X 3.412=btu's

Try dealing with 1/4 million BTU load changes.

[wdrzal]

Originally Posted by gomeler

True I understand that, but what about the huge differences between idle and load, being nearly 150 watts different? That is what I am trying to combat, not trying to improve load temperatures. A system charged to hold a load will act overcharged in an idle state, correct? I notice this behaviour with my smalle runits, I can imagine this is even more pronounced on quad-core tuned systems.

150w X 3.412=btu's

Try dealing with 1/4 million BTU load changes.


Most people over charge units,I think we remove more refrogerant than put in when we get called to a new job since the previous companycoulnd't figure out the problem.

you must find and fix the problem ,just not treat the systoms

[n00b 0f l337]

Yes it is more pronounced on quad core coolers, I combat it with a accumulator and a SLHX of sorts.

[[XC] gomeler]

I guess walt wanted to get his point across I think he is trying to pad his post stats *gasp*

[TopherTony]

How is this project coming along?

[TopherTony]

Any update?

[[XC] gomeler]

Funny you should ask, I built what I described above and was using it on my 1/2HP rotary singlestage and it worked like a charm. Probably overkill, a simple tube-in-tube slhx would get the job done. No refrigerant slugging when going from a 225 watt to 0 watt load so it served it's purpose.

[sacha35]

Nice one Gomeler any pics of the setup and temps mate.

[[XC] gomeler]

Yesterday/this morning I actually tore apart that system and scavenged the compressor and suction line for the autocascade I just built :-\ Will be posting a thread about that later once I can get all the bugs worked out, having trouble going below -55 celsius with r290/r744.

[Xeon th MG Pony]

use an accumulator/sub cooler assembly and kill two issues with one swap in

http://www.rparts.com/Catalog/Major_...cumulators.asp < Second row down nifty units look handy as hell too in simplifying pipe routing.

[TopherTony]

Originally Posted by Xeon th MG Pony

use an accumulator/sub cooler assembly and kill two issues with one swap in

http://www.rparts.com/Catalog/Major_...cumulators.asp < Second row down nifty units look handy as hell too in simplifying pipe routing.

and how would one go about implementing these in a SS?



I imagine the capillary goes through the middle coil and on to the evap, and the suction line goes in the right side and the liquid falls to the bottom cooling the coil and the gas exits the top on the left little pipe???

[Xeon th MG Pony]

Thees really aren't meant for such small systems, but by the sounds of it a quad core system just may make the minimal HP rating for it.

[TopherTony]

well it wouldnt be too hard to replicate and make one, i suppose

btw the compressors they are selling are 3 cc displacement and 12-24 vdc. These accumulators are made for use on these compressors, no?

and if they had to be smaller for our app, we can shrink the diameter from 4 cm to 2-3 and lessen the height by a few cm's as well

[n00b 0f l337]

The Quad core cooler for harvshark has an SLHX. Its 12" of 1/4" in 10" of 1/2". Works very well. The trick is to at idle, lower the fan speed and let the SLHX take a bigger hit. At load the SLHX gets half frosty and the capillary tube around the outside turns icey.

[Xeon th MG Pony]

They are meant for systems at least .13Tons.