Built to Last: Underground Piping for District Heating and Cooling

Underground thermal distribution pipelines are common at institutional facilities where thermal energy is generated at a central utility plant and is distributed to various buildings (otherwise known as district energy or district heating and cooling). Chilled water, hot water, or steam is created and distributed through a network of underground pipelines to provide building heating or cooling. The high range of pressures, temperatures, fluid properties, and other design considerations observed in these underground thermal piping systems can present many technical challenges. There are many factors to consider in selecting and specifying the appropriate underground thermal piping system including service pipe material, insulation material and thickness, corrosion protection and jacket material, expansion and contraction considerations, field-insulated vs. factory-insulated, and constructability/cost considerations.