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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.

The smoke generated from building fire prefers to the vertical shafts such as the stairwells and elevator shafts, due to the temperature differences. The smoke movement is of vital important in the vertical passages. The numerical simulations for the natural smoke extraction via elevator shafts are conducted, that provide the impacts of the gaps around elevator doors, the sizeable top vent in the shaft and the location of fire source, on the amount of smoke exhausted. The results indicated the feasibility of natural smoke venting through the elevator shaft, which will increase the neural pressure plane upward near the total height of the high-rise via increasing the top vent area. The gaps around elevator doors have less impact on the smoke extracting compared to the size of top vent. The floors above the neutral plane would be smoke-free and that increase the life safety of habitable areas.

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.

As the economy developing rapidly, the quota of natural gas in Chinese energy consumption is increasing rapidly. Meanwhile, the natural gas transportation pipelines have been developing quickly and the pressure of the pipelines is also becoming higher and higher. So the pressure energy stored in the pipelines is tremendous. This paper analyzed the gas-steam combined cycle based on the recovery of pressure energy in the gas transportation pipelines. The high pressure natural gas expands in the expander to recover some work to drive the air compressor, and then the lower temperature and lower pressure natural gas from the expander goes to cool the air which is going into the compressor and the exhaust of the turbine successively. Then the lower pressure natural gas recovers the heat of the smoke which is going to exhaust to air. At last the lower pressure natural gas is heated by a certain temperature and supplied to the consumer. This paper makes a qualitative analysis of the benefits brought by the new flow to the combined cycle. Generally speaking, the new cycle will increase the efficiency of the combined cycle and the utilization rate of energy.Copyright © 2008 by ASME