Real Range of Bedding Materials for Underground Heating Networks

Description:

The success of the “energy transition” in Germany to achieve the current target of CO2 neutrality by 2045 largely depends on a successful “heating transition”. The existing 30,000 km of district and local heating networks, i.e. around 60,000 km of pipelines, must be fed with renewable energy and waste heat sources. The existing heating networks must therefore be adapted to the conditions of the heat sources, further developed and significantly expanded - as politically desired - in accordance with the rules of our market economy. Heating networks consist of “warm-running”, mostly underground pipelines, which move in the surrounding soil during operation due to changing medium temperatures. This results in intensive interaction between pipe and soil, which has a significant influence on pipe stress. This results in special requirements for the bedding materials, i.e. the backfill materials in the pipe zone of district heating pipes.

The research objective is to expand the range of possible soil materials that can be used as backfill material in the bedding zone (bedding material) of district heating pipelines. In this way, increasingly scarce sand resources can be conserved and the economic cost of pipeline construction reduced. In order to achieve the research objective, alternative bedding materials must be used in both laboratory and pilot plant tests and systematically investigated regarding the properties relevant to the load-bearing behavior of a hot-running pipeline.