R404A Pipe Size

[gwapa]

Dear friens

I am design a coldroom Long 120 m L x 14 m wide x 12 m H
Refrigerant 404A o 510
Room Temp -28ºC
Refrigeration Load 210 kw
Evap temp –33ºC
Suction Temp -35ºC
I selected 12 evaporators 17,5 Kw each
The diameter of suction pipe is more or less 150mm (6”)
A 6” copper tube is very difficult to find locally
I have the following alternative
Use stainless steel pipe and weld with brach to copper
What other alternatives could I have?
Appreciate your comments
Gwapa

[Magoo]

Stainless schedule 10 would be ideal, what about several smaller suction lines and header them in plant.
Alternative is schedule 40 mild steel, should be API seamless A630... rated for low temp with WPL6 low temp bends and fittings etc., make sure that they are pickled/ cleaned before installed

[gwapa]

thanks Magoo
4 tube 2 5/8" will be oK. I will conect three evaporators on each one.
It is a spencer solution but thechnical featible

[suny]

Dear Gwapa
SS schedule 10 will be ok. But weld with a Tig (Argon Gas) welding machine. Did you take into account of the following when calculating the ref load of 210 Kw. 1) Refrigerant multiplier. 2) Evap fan heat load. 3) Defrost heater load. 3) Correction factor for SST. 4) RH vs KTD. 12x17.5 Kw = 210 Kw. If you have not accounted the above, the evaps are under capacity. Please make a note of it. This is for your info please.

[Eeram]

On 210 kW with R-404A, -35 deg C suction and 40 deg C condensing you would need 4 1/8" Suction Line, 1 5/8" Liquid Line, 2 1/8" Discharge Line.

For each 17.5 kW evaporator coil, you would need 2 1/8" Suction and 5/8" Liquid Line.

6" Suction line will upset the velocity. 4 1/8" Copper Tubing should be easy to get, as well as fittings/reducers.

[D.D.KORANNE]

Individual suction lines for each each evap in a common suction header will also lend a flexibilty should there be a drop on an evaporator . Oil management for compressor will be very critical during load variation/modulation.
A microfiber oil separator will be needed .