Prediction of thermal transients in district heating systems

Abstract

A prediction of thermal transients in district heating systems is important in order to adjust in an energy efficient manner the loads of heat power plants and pump stations with dynamic consumption needs during changes of the outside air temperature, the wind intensity, the solar radiation, or system start-ups and shut-downs. A model and corresponding computer code are developed with the aim to simulate the thermal transients in district heating systems. They are based on the high-order accurate numerical solution of the transient energy equation, and the hydraulic prediction of pressure and fluid flow rates within the complex pipe network. Thermal transients caused by an increase and decrease of the heat power plant load are simulated for real operating conditions of the district heating system. Predicted temperature front propagations show a good agreement with data measured at three consumer substations located in different parts of the district heating network and at different distances from the heat plant. The developed computational tool provides reliable information about time periods of temperature fronts propagation and heat distribution from the heat source to consumers within the whole district heating network.