INFLUENCE OF PIPELINE INSTALLATION AND OPERATION FEATURES ON THE ENERGY EFFICIENCY OF HEATING NETWORKS

Abstract

Heating supply systems are currently widely used to transport heat from sources to consumers. In new construction and network reconstruction, pre-insulated pipelines—either steel or plastic pipes in polyurethane foam insulation and polyethylene or steel casing—are the most common. These pipes are generally installed in a trenchless manner and, despite reinforced thermal insulation, still lose some heat from the heat carrier. Since these pipes have a standard economically justified thickness of thermal insulation, efforts to reduce heat losses need to focus on the areas of pipeline installation and operation. The amount of heat loss depends on the installation method of the pipes. This paper examines methods of installing heating networks using pre-insulated pipes, studies methodologies for calculating heat loss from the pipe casing to the ground, presents calculation results of heat loss depending on pipeline burial depth, and provides key energy-efficiency recommendations regarding specific features of heating network installation. An analysis of literature sources reveals that key factors affecting heat loss in heating networks include the moisture content of the sand and soil around the pipe, the mutual influence of adjacent pipelines, burial depth, and insulation thickness. The study examines the impact of pipe layout in a trench on heat loss. It was found that installation in non-accessible channels, while increasing capital costs, reduces specific heat loss by 8 W/m in the supply pipe and 7 W/m in the return pipe. This reduction is comparable to the heat loss decrease achieved by lowering water temperature, though not always technically or economically feasible. The trench installation of steel/polyethylene pipelines with high-temperature heat carriers in non-accessible channels with enhanced waterproofing and sand padding is a rational solution for energy savings as well as operational safety.