Rotary Single Stage - LG 18700 btu

[Obijuan83]

My first attempt building a Rotary Single Stage.

I will use:

12000 BTU LG Rotary compressor RE207 r407c
Base plate and condenser from an 3/8+ Aspera Unit
BartX evaporator and mounting kit
Flexible refrigerant hose
~2m-2.2m of 1.06mm captube

The Rotary will convert to LBP with r404a.

Today I started putting parts together

[makaka]

well look like a great unit . it is 2hp compressor ?

[Charles Wirth]

Good to see new builds, considered a PEV?

[Obijuan83]

well look like a great unit . it is 2hp compressor ?

Yes its a 2hp compressor

[Obijuan83]

Good to see new builds, considered a PEV?

I am not familiar with PEV, how far from evap can I keep it?(in centimeters?)

[Obijuan83]

A little progress with copper lines

[Charles Wirth]

Ideally you would install on top of the evap.

After much testing I found the PEV to handle the load better with larger compressors vs cap tube design. I am currently running a two ton Sporlan valve on a 1HP compressor.

[Obijuan83]

Can you share a photo of your build to take an idea?

[nachtfalke]

Hi , nice build
if you permit i can add some suggest to your build .
rotary compressor are very hoter compressors , it can reach in normally operating sistem till +120 degree.

if you havent used before an rotary you should know that this compressor electrical engine are cooled by HOT GAS , and NOT by vapour as the reciprocating use electrical engine bottom.
this mean crankcase of the compressor SHOULD be cooler as the discharge pipe hot gas, if the crankcase is hoter that mean something goes wrong with your superheat.( add more flow - short the cap tube , change cap tube to another large inleet)

rotaryes are made for hight back pressure application ( + degree application), using as refrigerant R410a , R407c or the newer R32.(replace R410a) , that mean in the suction they play with ~8 Bar , but in LBP you will be near 0 - 0,5Bar not every rotaryes will like this pressure in suction , they will got very hot the solution is to use a large inleet cap tube , or shorter that actually you use , that add more Flow .
R410a design use a large electrical engine and small compressor pump compared to R407c desings compressor ... that way best compresor for our OC condensing units are the R407c rotaryes.
the BTUs ( brithis thermal units) are calculated regards ASHRE tests for an 7,2C* evaporating temp using his refrigerant R410a , with ~ 5,5kw cooling power but his displacement ~ 22-23 ccm? , in LBP you will be intrested about displacement of the compressor .
the compressor that you use are an large electrical engine with an small pump .so this compressor will eat more power input at his pay for his performance in LBP , in LBP application( R404a , R507 , R452a , R449a etc..) you wont need large engine but need large pump , because you play at low suction pressure!
as example : an R407c compresor with 18.700BTU should have over 30ccm witch will be a beast

another tips is to use the discharge pipe sizing as the compressor port are ...in your case think is atleast 8mm or 9,7mm ( 3/8`) to avoid to overheat the compressor ,

the suction pressure can be 10 or 12mm that arent very crucial in LBP , but discharge pipe are!
hope my tips will help you!
regards!

[Obijuan83]

Hi , nice build
if you permit i can add some suggest to your build .
rotary compressor are very hoter compressors , it can reach in normally operating sistem till +120 degree.

if you havent used before an rotary you should know that this compressor electrical engine are cooled by HOT GAS , and NOT by vapour as the reciprocating use electrical engine bottom.
this mean crankcase of the compressor SHOULD be cooler as the discharge pipe hot gas, if the crankcase is hoter that mean something goes wrong with your superheat.( add more flow - short the cap tube , change cap tube to another large inleet)

rotaryes are made for hight back pressure application ( + degree application), using as refrigerant R410a , R407c or the newer R32.(replace R410a) , that mean in the suction they play with ~8 Bar , but in LBP you will be near 0 - 0,5Bar not every rotaryes will like this pressure in suction , they will got very hot the solution is to use a large inleet cap tube , or shorter that actually you use , that add more Flow .
R410a design use a large electrical engine and small compressor pump compared to R407c desings compressor ... that way best compresor for our OC condensing units are the R407c rotaryes.
the BTUs ( brithis thermal units) are calculated regards ASHRE tests for an 7,2C* evaporating temp using his refrigerant R410a , with ~ 5,5kw cooling power but his displacement ~ 22-23 ccm? , in LBP you will be intrested about displacement of the compressor .
the compressor that you use are an large electrical engine with an small pump .so this compressor will eat more power input at his pay for his performance in LBP , in LBP application( R404a , R507 , R452a , R449a etc..) you wont need large engine but need large pump , because you play at low suction pressure!
as example : an R407c compresor with 18.700BTU should have over 30ccm witch will be a beast

another tips is to use the discharge pipe sizing as the compressor port are ...in your case think is atleast 8mm or 9,7mm ( 3/8`) to avoid to overheat the compressor ,

the suction pressure can be 10 or 12mm that arent very crucial in LBP , but discharge pipe are!
hope my tips will help you!
regards!

Thanks for your suggestions!

So instead of 1/4 discharge pipe I should go better with 3/8 pipe?

Also, I was a advised to use 1.06mm captube around 2.0-2.2m for ~300w load, what is your opinion?

Also I can return the r410c 18.000BTU (22cc) and get an r407c 18350BTU(31.3cc) , you think I should do it?

Thanks in advance

[nachtfalke]

hey ,
i would go for discharge with 8mm(5/16) instead 1/4 (6,35mm ) , this configuration are used for small compressors (under 20ccm).
one of refrigeration rule say that you should use the inleet of the compressor port siezing , but your compresor are designed for + degree apllication , so it is a must that your discharge to be atleast 8mm (5/16), for suction i would go for 12mm (1/2 )

1mm inleet of cap tube can do maximal 350-380w load , witch for displacement of the compressor ( 22-23 ccm)should be OK , i?ll start with 2,5m but i think you will end at 2,2 to 2,3m for that load !

if you wanted a really strong unit then i?ll go for R407c 31,3cc compressor , but use a large inleet cap tube i say 1,4mm to add more flow to hold over 500W heat load .
the PVE is parker electronic valve ....they are very good in stationary evapoprators , for overclokers need arm mobility , you can hold also very good load if you play with large inleet of cap tubes...for example in mine single stages /cascades i use even 2mm 2,3mm inleeet cap tubes

we can also move ther discution in privat for more tips !

[Charles Wirth]

I used to have pics, I will need to locate as I am going based on experience with both at the evap and how I have the valve now 3' from the evap. I have .25" feed tube to my block now.

Having at the evap was faster and stronger.

[Obijuan83]

Update

I change the Rotary to a 12000 BTU Mitsubishi 20.7cc r407c that Nachtfalke suggested.

Discharge pipe is 5/16"
Suction pipe is 3/8"
1/4 sae Gauges

[Charles Wirth]

Huge and nicely done, I run copper like a crazy person.

[makaka]

nice and clean :-) .
did you solder the flexible tube or it is just threaded , those trend to leak if not soldered .
we need some numbers already :-)

[Charles Wirth]

I have a few fittings on my cascade, bottom of the oil seps and the schrader valve my concern a decade ago.

My cascade has not lost 1PSI since I gassed it a decade ago and I run it a lot.

Expansion tank is very helpful, I did not see what gasses you are planning?

[Obijuan83]

Finally up and running!

Trying to tune it

[Obijuan83]

I tried with i7 3930k 6c/12t @ 5.25GHz 1.6v , not attached -64C, idle -58 , load -52 @ end of CBr15

[makaka]

very solid temp , congrats . any chance to take a video of the unit running to estimate noise level .

[Obijuan83]

It is noisier than the Aspera NEK2150GK (1/2+hp) I had before for sure.

But it is a beast(for my use) it can hold a:

-i7 3930k (350Watt) @ 5.35GHz @ 1.69v in x265 4k
@ idle -57.0C / load -47.0C

-Sempron 150 (125Watt) @ 4.55GHz@ 1.7v in Spi32M
@ idle -60.5C / load -58.5C

[makaka]

sound like a lot of fun and hardware here .
what where the Aspera NEK2150GK (1/2+hp) numbers for the same load ?

[Obijuan83]

NEK2150GK was around -32C at load (x256 4k)with a 3770k/7700koverclocked and -42C at load with a Sempron overclocked, so about 15C difference

Idling around -48C

[makaka]

maybe then a blend of 70/30 r507 and R410 will give you another 10-15c :-)

[Obijuan83]

Some improvements, I add a 220v fan regulator due to low ambient temp.

[makaka]

almost -53 load temp awesome