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In order to reduce the power consumption of circulating pump in secondary network., the adjustment that combines quantity adjustment and quality adjustment is proposed in the paper;and the control strategy and adjustment equations in different stages of this adjustment mode are present. Then taken a community in Zhangjiakou as an example, the adjustment curve of this mode in indirectconnected heating systems and direct-connected heating systems are obtained. Finally the power consumptions of the adjustment mode proposed in the paper with that of quality adjustment and quality adjustment with different quantitative ratio in each period are compared; the result indicates that the adjustment mode has more potential in energ-saving.

This paper introduces the adjustment curve equations of district heating system commonly used in secondary network. On this basis, adjustment curve equations of the adjustment that combines quantity adjustment and quality adjustment are proposed. Then taken a community in Zhangjiakou as an example, we compare the power consumption of the adjustment scheme proposed in the paper with that of quality adjustment and quality adjustment with different quantitative ratio in each period. The analysis shows that the adjustment scheme has much more potential in energy-saving.

With the development of the heating industry, the higher level of operation and management are required. Therefore it needs more accurate values of nodes pressure and flow. In this paper, based on the genetic algorithm, In order to realize the improved algorithm, change the rate of cross and mutation according to the fitness. After revising the resistance characteristic coefficient, we can get the more accurate values of nodes pressure. Finally, an example is given to verify the feasibility and validity of this method.

To direct at heating system when it adopts quantity adjustment. Taking a community in Zhangjiakou as an example, using the method of Graphic theory to analysis and compare these two operation schemes: adjusting parallel pump's valve in shared pipeline and adjusting parallel pump's valve in non-shared pipeline. We can know that adjusting parallel pump's valve in non-shared pipeline is energy-saving, when the flow in pipe network is bigger than 79% of the boiler's total circulating water. There is a lowest limit of system's circulating water, when adopt the method that adjusting the parallel pump's valve in non-shared pipeline, otherwise it would damage the pump.