Energy Conservation Method Research Of The Variable-Frequency Primary Pump In Air-conditioning Chilled-water System

In the application of central air-conditioning, the technology of variable-frequency primary pump has been widely studied. This thesis analyzes and researches the application of variable-frequency primary pump technology.First, the thesis introduce traditional calculation of the energy consumption, it is to presume that the pump's efficiency is unchanged before and after variable-frequency,and then use the equation of proportion law to calculate the energy consumption.Though the analysis of pipe' pressure drop and the efficiency curve,points that the efficiency after variable- frequency is variable. We should determine the same efficiency curve according to the flow and pressure drop of the new work point.The point which cuts with the original H-Q curve is the similar point with new point,then determine the efficiency after variable-frequency.Finally calculate the energy consumption after variable- frequency according to the formula of proportion law.Second, the thesis gives the energy conservation method, and the operating parameters in different options can be calculated according to the method. For multiple parallel pump, we should first judge if it can use some pumps to change frequency,and the method is to draw the curves of H-Q and all the parameters of the most disadvantaged loop on the same coordinate system,if the two curve cut,we can use some pumps to change frequency;contrarily use all pumps to change frequency.The traditional number of variable-frequency pump is determined according to payback period,but this method ignore the life of the equipments, the thesis considers the life and put forward anew concept——m,that is the benefits of the cost savings minus initial investment inthe life of equipment,and according m to determines the number of variable-frequency pump.Finally, the thesis gives the analysis of the variable-frequency schemes through a project, educes that the energy-saving effect of some pumps variable- frequency is better than the effect of all pumps variable- frequency.The thesis analyzes the energy consumption of traditional calculation and the actual energy consumption, and points that the energy consumption using proportion law is less than the actual.