Applicational Researching And Energy Saving Of Separate Power Way In Heating And Air-conditioning Systems

In heating and air conditioning water systems, when applying the traditional centralized power mode, the circulating water pump lift is selected according to the pressure loss of the least favorable loop and the other branch circuits are balanced by adjusting the pipeline diameters or using regulating valves to increase impedance and consume the excess lift. In distributed power system, pumps are set up on the main route or branch as well as the header piping. Each water pump lift can be chosen according to its need. By doing this, the regulating valve energy cost (including the energy cost for increasing resistance to achieve the balance of water power in other ways) can be reduced or eliminated. Therefore, the energy consumption can be saved more in the decentralized power system comparing to the centralized power system.In this paper, by using fluid transmission and distribution network program, the transmission energy consumption of a certain system are simulated and calculated in ways of centralized power and distributed power. The results shows that, compared to centralized power system, the energy can be saved by 31.91% in the direct-return system and 1.75% in the reversed return system in distributed power system in certain conditions. It shows that it is a significant energy-saving method to use distributed power way in the direct-return system.Quantitative analysis have been carried on the impact of system scale to energy-saving rate in the distributed power way. The results show that, the larger the system is, the greater energy-saving rate can be in the direct-return system while using the distributed power way.The matching of pump lift has been discussed in the distributed system, and the means and principles of selecting pump lifts in some different distributed power ways have been presented.Finally, a hotel air conditioning water system has been taken as an example to be carried on a energy-saving transformation in the distributed power way. The analysis and calculation results show that the transportation energy consumption decreases gradually with the step-down of the system power. As the system changes from the centralized power way to the distributed power of the primary branch line, and then distribute to the secondary branch line, the total energy consumption changes from 131.38kw to 91.11kw, and then down to 80.68kw, the proportion of the energy cost on regulating valve to the total energy consumption changes from 38.60% to 15.07%, and then down to 4.75%.