buried pipes heat transfer
buried pipes heat transfer
(OP)
say we have two buried pipes [1" id poly.} buried in 5" thick concrete floor,supply and return with ethylene glycol 50% circulating inside the pipes at 18F [5 usgpm], the pipes are 1.75" from top of pipe to concetre surface, at 4" on centres btw pipes , my question if we vary the flow and the centres to 3.5" how this will impact the heat transfer coefficient and proper method of calculation. we are trying to freeze the water sprayed on top of the concrete say 1-1/2" thick ice to make





RE: buried pipes heat transfer
TTFN
Eng-Tips Policies FAQ731-376
RE: buried pipes heat transfer
I'm not a real engineer, but I play one on T.V.
A.J. Gest, York Int./JCI
RE: buried pipes heat transfer
IRstuff (Aerospace)
At what air temp and ground temp?
The concrete temperature is 25F
Air temperature at the surface , 60F, 45F WB
Thanks
RE: buried pipes heat transfer
50% Eg through 1" Poly Pipe at 4" Centers at 5-GPM per tube for a full size rink is a BIG pump, 3-GPM/Tube would be more like ordinary. Big component of the heat XFER to an ice sheet is radiant, so knowing the air conditions near the ice surface will yield a reasonable number for required HT if the sheet is in the dark; but the intensity of color TF lighting is a big heat load on a pro-style rink.
The basic answer is:
42 Btu/sq ft. of Concrete Surface on 4" Centers; 47 at 3-1/2" Centers: Nominal 18 deg. (in) to 20-plus (out). Both at 3-gpm per tube and 1" Thick ice. Obviously lower brine temps required to support Thick Ice.
RE: buried pipes heat transfer
BigInch
-born in the trenches.
http://virtualpipeline.spaces.msn.com
RE: buried pipes heat transfer
How did you arrive to those load figures, what method of
calculation you used
42 Btu/sq ft. of Concrete Surface on 4" Centers; 47 at 3-1/2" Centers
Thanks