R744 Supermarket Rack

[750 Valve]

Hi guys, haven't been to RE in a while, nice to see some of the same threads STILL going
Thought I might show some fotos of an R744 (Co2) rack running in a supermarket. Store load is split over 2 cascade systems (R744/R507). Each R744 rack has 2 comps for the LT load, liquid recirc is used for MT&HT loads. 2 x H/Xchs as cond for R744/R507 evap and a normal 4 comp rack as hi stage. Hi stage is water cooled, closed loop with Guntner hybrid coolers used.
LP on R744 runs around 1400 kpa (-28ish SST), vessel kept at 2400 kpa (-11ish SCT), R507 rack runs around -15 SST to keep vessel -10 to -11 SCT. Copper pipe used for all pipe runs except larger dia. rack piping, largest size is 5/8" on shopfloor.
Sorry fotos are pretty avg, only had a camera fone, will try to get better res. shots.

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[rbartlett]

good to se you back - was re-reading the au thread and I did wonder where you'd got

cheers

richard

[Dan]

Hi 750! How much R507 is in your system?

[US Iceman]

Thanks for posting the very interesting pictures. I for one would be very interested to find out more information about this system.

[globalcooling]

Hi 750,fficeffice" />>>
Thanks for the interesting Co2 rack pix… and for sharing your nice “moustache” with us… just watch out for liquid flooding! ;o)>>

[Dan]

I wasn't allowed photos, but just got back from a CO2 secondary refrigerant startup in a Sam's Club. I noted that there was about 1,100 lbs of CO2 in the A rack, so I would expect the same in the other machine, more or less. At any rate, an exposure of leakage under $2,000.00.

They have a separate generator with a backup compressor to keep the pressures below 500 psig in the event of a power failure. My guess is the refrigerant charge is around 1,000 lbs of R404A.

I see much sense in using secondary refrigerants such as glycol and CO2, as we confine the piping, exposure, and voume of gasses that perhaps contribute to global warming.