Geothermal piping calculations

[prichmon]

We are looking at replacing a Cooling tower with Geothermal Cooling for a process water loop.

80KW total power usage.
10*F temp differential on cooling tower design
20*F temp design differential on system
operating pressure 30psi

If we move to geothermal cooling our temp differential will be ~35*F+ due to ground water typically not exceeding 60*F. The thought is to simplify the system by elimination of the HX, cooling tower and tanks.

Based on copper pipe of thermal transfer of 13.11 W/M^2*K; PE pipe 7.09 W/m^2*K

1" copper tubing
10*F differential copper equates to ~4595 feet pipe
35*F differential copper equates to ~1315' pipe

Based on data on ground temperature changes the loops need to be ~20' deep to minimize temp swings to the +/-10* range.

I would appreciate if someone with experience in this area could assist me?

Thank you

Rich

 

[NoHtPp]

I believe est:
in average N-TX soils there , some dampness, that the horizontal boring would be correlated to 12ft depths (or more if they can get to a stuck drill rod) and near 300ft per ton of to 96f out/ 88 back, in Aug-Sep to the ECL. gle, plastic piping, 20 ft apart runs... ~ 70 gpm, design for UNDER 50ft TDH for some efficient circulation (under 25 psi, all equipment and piping --- ALL in recirculation on the primary ground loop side, if just process cooling)

We have had since 1996 success in 3/4 acre pond , 11 ft deep rack--- coils at 9ft, 70f yielding on a flow of water of 56 gpm a 13 to 14 degree differential
~ 90-out to 87 supplying PROCESS COOLING from 10 coils x 1" PE dr-11; spaced coils (rewound) 6" on center, approx, 5 layers high (16" stacked, approx. 3" apart, like discs on a feeder); 7ft dia finished with 420 ft plus the tails to 5 coils/ea on 2 inch , twice; over 360,000 btuh) 30 net cooling tons in the winter, and over 26 tons net cooling in the summer..

2 hp to 3 hp depending on your header lengths and other Td's wanted which shut off 25 hp of refrigeration chillers and all that related maintenance and overhead operating costs.