Energy Saving Study On Flow Regulation By Power Change

As the requirement of energy-saving and indoor environment gets higher and higher, variable flow technology are widely used in heating and air conditioning systems, namely by changing power or resistance to adjust the flow of the system,subcircuit and terminal equipment so as to match usually mutative dynamic heat(cold) load variation. Flow regulated by resistance change is apparently uneconomical. In power centralized system, we have to change the resistance to regulate the flow of subcircuit and terminal equipments. With regard to centralized flow regulation, regulating by changing the power has been people's common sense and technical current, it mainly includes change the speed of pump and fan, changing their running number and the combine of the two.There are remarkable energy saving benefits of variable speed control of pump/fan, and it is deemed to be the best, but there is consanguineous relationship between variable speed energy-saving benefits of pump/fan and pipeline characteristics. By theoretic analysis and calculating the energy saving benefits of the pump,this paper analyzes its relation with the pipeline characteristics, based on the analysis advances a non-dimension forecasting method. The method is of important referenced value in evaluating the energy saving benefits of variable speed control projects and determining whether the project can use variable speed control or not. Flow regulated by changing the number of parallel pumps, during the regulating, working condition of individual pump or fan will change a lot, there will be two problems, one is efficiency of the pump or fan will decrease,anther is there will be overloading. By vast calculation and analysis, this paper advances non-dimension forecasting method of individual pump and system flow during the regulation. The result is of referenced value in avoiding overloading,equipment choosing and instructing operation.The combine of variable speed and running number of the pump, according to one flow, there are many combined schemes, and their energy consumption is different. Using four parallel pump, this paper analysis and compare the energy consumption of various schemes, its conclusion is instructional in optimizing this regulation.In conventional power centralized system, we have to use valves to balance the system and regulate the flow of the branch, so there is valve energy consumption. In power decentralized system, there are not pump/fan installed in main pipe, but also in branches, using the variable speed control to regulating the flow, valve energy consumption can be reduced or avoided, but the investment is higher and control is complicated. Based on hydraulic balance principle in fluid system, analyzing valves'energy consumption share in the power equipment's output power in...