Research On COP’s Changing And Comprehensive Energy Consumption Affected By Frequency Conversion Control In Air Conditioning Water System

Central air conditioning water system energy saving frequency conversion control technology has been widely used in practical engineering, and verified by actual operation test that the energy saving effect of implementing it is significant. There is no denying fact that the application of this technology will cause certain changes of chiller’s COP, and in this years many researchers have carried extensive studies in this aspect with some results. But nowadays the negative impact on the COP of chiller caused by this technology always tend to be ignored in the frequency conversion energy-saving of many existing central air conditioning water systems. Thus a central air conditioning system of a shopping mall in Shenzhen will be show as example to study the chiller’s COP and total energy efficiency COPz in theory and simulation when the system’s water flow is variable.This paper firstly elaborates the theory of COP’changing affected by variable evaporator water and variable condenser water, and draws preliminary conclusion: Chillers performance is less impacted on the variable evaporator water, but big impacted on the variable condenser water.After that, this paper builds the model of single stage centrifugal chillers mentioned, modeling the exact chiller plant load and controlling evaporator supply chilled water temperature at part load and verifying the veracity of the models.Then, state a detailed experimental study on the case of central air conditioning water system. Calculate COP value of every operating condition by using test data. At the base the above works, this paper concludes the regulation of COP’s changing with relevant parameters, and does contrastive analysis of the modeling conclusions and experimental calculated data. Also, it makes a summary respectively on evaporator water flow changing, condenser water flow changing, evaporator water and condenser water flow changing simultaneous.Finally, this paper establishes the energy consumption model of the central air conditioning water system’s equipments in plant, calculating the COPz value combining with the chiller’s model, and compares to the COPz’s regulation calculated by test data, reaching the changing rules on typical conditions of air conditioning water system operating with variable flow.