16. Operation Regulation of Combined District Heating Systems with Multiple Large-Scale Peak-Shaving Heat Sources

Combined district heating is one of the development trends of central heating in China, mainly due to its high flexibility, reliability, and energy saving potential. In this paper, we analyzed the applicable operation regulation ways for a combined district heating system with combined heat and power (CHP) plant as the basic heat source and two large-scale coal- and gas-fired boilers in primary heating network as the peak-shaving heat sources. Four operation regulation ways were studied in the paper, including quality regulation in different phases (alternative 1), quality–quantity regulation (alternative 2), quality regulation before combined heating and quality–quantity regulation after combined heating (alternative 3), quality regulation before combined heating and quantity regulation after combined heating (alternative 4). The results indicate that alternative 1 is constrained by the design supply water temperature of CHP plant. Alternative 2 has a relative high possibility to lead to hydraulic maladjustments. Alternative 4 requires high management capabilities and sound automatic control devices, therefore alternative 3 is recommended as the most applicable operation regulation way.