Pipes for ground heating
Depending on the size of area to be covered, Thermotech underfloor heating pipes in dimensions 17, 20, 25 and 32 mm can be used.
Normally, 17 and 20 mm pipes are used for areas of up to 300 m². For large areas, with long loops or high power demand per m², 25 and 32 mm pipes are used.
For small areas, 20-30 m², which require small radius or close cc-dimensions,17 and 20 mm pipes can be used.
You can use a pipe without a diffusion barrier if the system is connected to the heating system through a heat exchanger.
Recommended loop lengths
|Pipe dim||Wall thickness||c/c-dim||Power W/m2||Pressure drop||Temp||Loop length|
|17 mm||2 mm||200 mm||300/200||17/18 kPa||15 °C||60/80 m|
|20 mm||2 mm||200 mm||300/200||19/17 kPa||15 °C||80/100 m|
|25 mm||2,3 mm||250 mm||300/200||18/17 kPa||15 °C||110/140 m|
|32 mm||3 mm||250 mm||300/200||17/18 kPa||15 °C||170/220 m|
For detailed information and calculation examples download Thermotech GEO®System Product range & Handbook.
Which c/c-dimensions that should be used depends on the desired power per m², the intensity of the snow etc.
Some guidelines are:
- Dimension: 17 x 2 and 20 x 2 mm - 200 mm
- Dimension: 25 x 2.3 and 32 x 3 mm - 250 mm
It is important that the entire surface have the same c/c-dimensions.
The pressure drop per meter of pipe is listed in the pressure drop nomograms (see FAQ).
For 25 x 2.3 the pressure drop is 0.163 kPa/m. This results in a total pressure of 0.163 kP/m x 110 m = 18 kPa.
For 200 W per m² and 140 m long loops, the pressure drop is 17 kPa.