HeatFlex20. June 2019
KORDFLEX10. February 2020
New bedding material to reduce heat loss.
District heating pipes are used buried for heating networks up to 130 ° C hot water temperature. In the trench they are laid in a sand bed, resulting in a temperature gradient from the pipe to the edge of the chute as a result of the heat loss. With the innovative thermal sand, the heat losses compared to conventional cable sand can be significantly reduced.
Lambda cable edge: 1.5 – 1.7 W / m ° K
Lambda Thermosand: 0.177 W / m ° K
|Application:||As a backfill material for pre-insulated pipelines, which provide the necessary|
Properties of the tube static requirements according to ÖNORM EN 13941 must meet.
|Lambda – values:||dry: 0,177 W/m°K|
|wet: max. 0,88 W/m°K|
|slightly wet: 0,33 W/m°K (calculated value)|
|Reviews:||Review and confirmation of Graz Universitiy of Technology|
KELIT – Thermosand is a new type of bedding material which has the same mechanical properties and a significantly lower thermal conductivity than conventional quartz sand.
By using Thermosand (lambda: 0.33W / m ° K), the same losses are to be expected for a series 1 insulation pipe as when using insulation series 3 pipes with conventional cable sand. This considerably reduces the heat losses in the tube zone.
Thermosand is a ground waste material from former coal mining areas in Styria, which was formed by thermal conversion of coal residues and is similar to fired clay as “natural clinker”.
Naturally fired, reddish peat material (natural clinker) with high pore number, ground and on grain size 0/3 mm. These micro cavities only reach a water saturation level of max. 84% (on average approx. 65%). The remaining cavities are filled with air and cause good insulation properties.
• high porosity ensures much better insulation (dry and wet !!!)
• mechanically stable
• sufficiently available
Soil mechanical suitability:
The soil mechanical suitability was determined by extensive tests on the technical University of Graz (TUG) at the Institute of Soil Mechanics and Foundation Engineering. (Test No. 2045).
In a comparative assessment, the suitability of the thermosand® as a backfill material, which have the necessary properties to fulfill the tube statistics requirements according to ÖNORM EN 13941 must, confirmed.