Dynamic integrated control for Chinese district heating system to balance the heat supply and heat demand

Abstract

District heating system (DHS) mainly consumes fossil fuel in North China. Reducing energy consumption of DHS is conducive to low-carbon sustainable development. Poor matching of heat supply and heat demand limits the efficient operation of the district heating system. To solve this issue, a dynamic integrated control method of buildings and heat exchange station (HES) is proposed. On the building side, five heating patterns are designed for space heating of buildings based on their indoor demand temperatures. On the HES side, to produce the accurate heat supply, four correction factors are introduced to modify the temperature-flow equations based on the DHS configuration difference between actual operation and design conditions. Five total correction factors are integrated to determine eventual regulation equations. Then single-level and double-level reverse control strategies are presented. A case study is illustrated to validate the proposed approach. With the integrated control, the matching values of calculated heat supply and actual heat consumption were 85.46%∼96.90% of buildings and over 90% of the whole DHS. Four years of operation data indicated the 12.75%∼31.08% of heat-saving rate and 5.23%∼24.62% of electricity saving rate, which brings about total emission reductions of 3803 tons CO2, 35 tons SO2 and 10 tons NOx.