Research And Application Of Energy-saving Through Frequency Conversion Control In Air-conditioning Cooling Water Pump

With the development of economic and technology,a variety of intelligent buildings and production processes have high demand for air-conditioning,the time of air-conditioning supply is greatly extended,and even supply throughout the year. However,air-conditioning load difference is large because of different seasons,different weather and different time,according to the statistics,in eighty percent of the running time in modern buildings,the actual demand load of air-conditioning is less than the sixty percent of design load.In the past,because of the constraint of the freezer controlling technology and the traditional concept,the first chilled water system and cooling water system of air-conditioning usually adopt frequency flow system.In a year,the cooling water system often run under the state of lager flow,small temperature difference and low temperature,which is neither energy saving nor the safe running of compressed air-conditioning freezer.In order to response to the national energy consumption and the development of science,we analysis and research on the feasibility and concrete implementation energy-saving method of frequency conversion controlling system of compressed air-conditioning freezer in the field of airconditioning, which have significant social and economical benefits.In response to these circumstances,I consulted the technical data and analyzed views of previous similar issues.According to the principle of compressed airconditioning freezer,operation requirements and operation characteristics of cooling water system,after careful analyzing,researching and actual measurement,the cooling water temperature T1 of entering the freezer condenser(or cooling tower outing water temperature) mainly depend on the ambient temperature,humidity and cooling tower case,the load of freezer have a relatively small impact on it,The cooling water temperature T₂ of outing the freezer condenser(or cooling tower entering water temperature) is mainly determined by the load of freezer,condenser heat transfer case, cooling water flow and entering temperature,by which we develop a program about energy-saving variable frequency control in air-conditioning cooling water pump,we adopt the cooling water temperature T₁ of entering the freezer condenser(or cooling tower outing water temperature ) to control the start and stop or running frequency of the cooling tower fan,determine that the cooling water temperature T₁ of entering the freezer condenser(or cooling tower outing water temperature ) is on the safe temperature range of the freezer.Based on the cooling water temperature T₂ of the freezer condenser, we control the cooling water pump to adjust the running frequency according to the cooling water temperature T₂ of outing the freezer condenser,avoiding the subsection breakpoints step type adjustment,achieving the purpose of energy-saving in the premise of the safe,normal running of the freezer.According to the program,I design and implement Energy-saving variable frequency control in air-conditioning cooling water pump in a well-known company data center combining with my practical work,which combine with the cooling water system,converter,monitoring and control equipment and the Building Automation System(BAS),forming a ring frequency controlling system and a running supervising system of air-conditioning cooling water pump. Through repeated testing and debugging,the method not only guarantee the safe,normal running of freezer,but also obtain the comprehensive energy-saving effect of airconditioning refrigeration system.The energy-saving effect is very clear under the external environment of low temperature,low humidity and low-load operation freezer cases on spring,autumn and winter.