Fibre optic and embedded sensing concept for long term monitoring of distrct heating pipes at the District-LAB Kassel

Abstract

District heating systems are expected to operate with lower temperatures and a higher share of renewable and volatile heat sources, which increases the need for experimental data on pipe soil interaction and insulation behaviour. This paper presents the concept and realisation of a full-scale district heating test section within the flexible heating grid of the District-LAB at Fraunhofer IEE in Kassel. The measurement setup combines distributed fibre optic temperature sensing on the pipe surface, in the bedding and in the surrounding soil with embedded temperature and humidity sensors in the PUR foam and soil moisture sensors close to the pipes. The paper focuses on the design, installation and initial functional checks of this integrated measurement concept, which provides a platform for future investigations of heat losses, insulation ageing and moisture processes under realistic and dynamic operating conditions.