U-turns of geothermal probes Ø32 and Ø40 mm

What is the difference between geothermal probes Ø40 mm and Ø32 mm
The amount of heat that a geosonde Ø40 mm (with a pipe wall thickness of 2.3 mm) can collect is 1.6 times greater than a Ø32 mm geosonde (with a pipe wall thickness of 2 mm):

Q40/Q32={π×([40-2×2,3]/2)²}/{π×([32-2×2]/2)²}=1,6

Usually geothermal probes are made of 2 Ø40 mm pipes. Occasionally, probes consisting of 4 Ø32 pipes are also used, for which we specially manufacture Y-turns.

How to sink a geothermal probe into a borehole
When drilling a borehole, a viscous suspension of water and clay is used to keep the borehole from collapsing. Over time, the clay will settle to the bottom of the borehole, so once drilling is complete, the geosonde should be loaded quickly.
Before sinking, the geosonde is filled with water or antifreeze to increase its weight and the probe is pressurised to check for leaks. The density of the slurry is greater than that of the filled probe, and the slurry pushes the geosonde out of the borehole.
Drillers can use their own weight to push the geosonde into a borehole that is up to 50 metres deep.
For boreholes deeper than 50 metres, manufacturers of geosondes make special weights, up to 90 mm in diameter and weighing up to 30 kg, from metal and suspend them from the end of the probe. The result is the weight:
   - is relatively expensive;
   - sinks slowly in a borehole Ø90...130 mm filled with a viscous suspension. Specially for load increase diameter of a hole up to 130...180 mm that increases a price of drilling;
   - takes up space in the borehole, reduces the length and efficiency of the geothermal system; 
   - often does not reach the bottom of the borehole because of clay deposited at the bottom;
   - occasionally hits something in the middle of the borehole, lays on its side and jams.

We use a unique technology to submerge geothermal probes using drill rods and Ø4...6 mm metal rod, and we manufacture appropriate universal U-turns that can be used with both weight and drill rods.