Rotary cascade worklog (56K warning !!!)

[Stelios]

Part list :

1st stage compressor : Hitachi 24000btu ... 41.7cc
2st stage compressor : Hitachi 18000btu ... 30.7cc
1st stage condenser : 1HP with 300mm EBM fan blade.
Main heat exchanger : 30 plate
2nd stage desuperheater : 1/6hp .

Filter driers are from Danfoss (Eliminator series)
I'll attach 4 gauges for both stages (low & high pressure)
Low stage will have pressure relief and pressure shutoff controls .

Both stages with captube 0.031" .

So far i have almost finished the first stage










Heatexchanger has a small charge of ethylene in the 2nd stage side (in order to avoid condensation during 1st stage testing) .


I started vacuuming and here's the micron gauge meter ...


1st stage gauges during vacuum .




And here's the first run with R410A in the 1st stage . The thermometer on the right measures just after the condenser (subcooling) .
-60.7C is a few cm after the heat exchanger .



Running pressures ...




Room temperature is around 25C so it's pretty normal so far .

Captube on the 1st stage is dual 0.031" (in parallel) about 1.45m each .

I'll update soon .

[Tetrafluorometh]

Am i right in saying the 1st stage is in a deep vacume at least? How much does the

Hitachi 24000btu ... 41.7cc

cost or where you get it from?

[Stelios]

Am i right in saying the 1st stage is in a deep vacume at least? How much does the cost or where you get it from?

Yes . Nice vacuum so far . From my experience with other rotary cascade units , it will hold vacuum all the time . Of course not so low ...

The compressor is bought here in Greece (Europe) at a cost of approx 200 Euros . It's for R407C gas , but it will work with R410A with no problems .

Exact model is : CHV33YC6-U

[Tetrafluorometh]

Yes . Nice vacuum so far . From my experience with other rotary cascade units , it will hold vacuum all the time . Of course not so low ...

The compressor is bought here in Greece (Europe) at a cost of approx 200 Euros . It's for R407C gas , but it will work with R410A with no problems .

Exact model is : CHV33YC6-U

WOW thats cheap. Thank you

[piotres]

Nice cascade .

BUT IMO R410a isn't good for 1st stage, You got 17bara unloaded (I know it's 25C ambient but still pressure is high), with load it'll be over 20 bara IMO so too much . R404a or R507 is good choose.

Compressors are STRONG so it should be good unit .

R1150 on 2nd stage?

And what has been the deepest vaccum You have been able to pull (reading from VG64) ??

[Stelios]

Nice cascade .

BUT IMO R410a isn't good for 1st stage, You got 17bara unloaded (I know it's 25C ambient but still pressure is high), with load it'll be over 20 bara IMO so too much . R404a or R507 is good choose.

Compressors are STRONG so it should be good unit .

R1150 on 2nd stage?

And what has been the deepest vaccum You have been able to pull (reading from VG64) ??

Hello Peter ,

I know what you mean about R410 , but i only experience such problems with small condensers .. or long captubes .
In other cascades that I have used the same condenser i didn't have any pressure issues (up to 260-270psi with 340W heatload).

About the VG64 ... Lowest value i got while vacuuming 1st stage was about 540microns . After 15-20 minutes it got to 600 .
The absolute lowest i have seen is about 150microns while vacuuming in a single stage . Of course with triple vac and breaking vacuum with nitrogen.

Thanks for your comments .

[Stelios]

Time for a little update .

2nd stage is almost done . All it's missing is the suction line with the evap & captube ... and the pressure shutoff & relief equipment .








I vacuumed and filled with dry nitrogen (It sits there about 10 days now) .



Now , about the evaporator ...
It a special design from Eleven . A 50mm diameter .Many thanks for this !!



... and brazed with nitrogen flowing inside ...







Of course it needs cleaning/sanding etc .



Finally ... suction line (and braiding) . Also brazed the evap on it .



And the pressure test with nitrogen at 500psi overnight .



More to come soon .

[wdrzal]

" QUOTE" :"And here's the first run with R410A in the 1st stage . The thermometer on the right measures just after the condenser (subcooling) .
-60.7C is a few cm after the heat exchanger" . -60.7 is NoT subcooling.

How to measure subcooling:

Using a pressure temperature chart, find the saturation temperature for the pressure you recorded . The difference between the measured temperature and the temperature from the pressure temperature chart is the subcooling. Adequate subcooling is needed to overcome any liquid line pressure drops.

[sdumper]

Here this might be helpful

www.hvac-pro.org/articles/superheat.pps

[Stelios]

" QUOTE" :"And here's the first run with R410A in the 1st stage . The thermometer on the right measures just after the condenser (subcooling) .
-60.7C is a few cm after the heat exchanger" . -60.7 is NoT subcooling.

How to measure subcooling:

Using a pressure temperature chart, find the saturation temperature for the pressure you recorded . The difference between the measured temperature and the temperature from the pressure temperature chart is the subcooling. Adequate subcooling is needed to overcome any liquid line pressure drops.

Of course -60.7 is not subcooling . You didn't read carefuly what i wrote .
Checking the picture , the thermometer on the right measures 26.4C . I have two thermometers there . -60.7C is on the first thermometer on the left .

Here this might be helpful

www.hvac-pro.org/articles/superheat.pps

Sdumper thanks for the link .It's nice to have lots of information gathered

[subzero 1979]

my precious
good work my friend stelios

[subzero 1979]

my friend stelliuos i have the cascade one year
i think is time to show the monster