| The paper is an application study for an useful saving of water pump running, atair-conditioner coolant tower Viasystems EMS (Shenzhen) Co., Ltd. Fully voltage runningmode is commonly used in coolant tower for air conditioner for long time at all of works oflife. The reason is the control system is not only simple, but also it is lower investment. Onthe other hand, it is possible waste great of energy due to lack of make workload and poweroutput relations at dynamic condition. It is necessary to set up timely control system to fuliflla need of cost reduction for company business and to obey the energy saving policy in China.First of all, it is based on the basic pirnciples of converter-dirven circulatingwater pump,actual workload condition, air-conditioner speciifcations and production process, to closeanalysis of energy figures and to estimate energy saving rate. And then, it is made threeoptions on control. Finally, it is done decision making. A system, which consists of FrequencyConverter and Programmable Logical Control (PLC) to dynamic monitor and automaticcontrol a coolant tower for central air conditioner is worth doing to study. It can ifnd a lot ofmateiral about this topic in China, something is memoir, most of them are absorbed in theorystudy, but at simulation stage only; another is application style, focus on effectiveness, butlack of technical analysis details. Refer to those experiments, I have taken a lesson to doFailure Mode and Effects Analysis (FMEA) and deifne relative action items so as to reducedesign irsk at beginning stage.Secondly, it is to design program and set up parameters. Certainly, all of them will baseon the principle of main equipment to do design. There are including，(l) Making system maindiagram, which consists of two set of power supplies, one is frequency converter mode fornormal use, and another is oflly voltage running mode for back up; made use of DC mA forconverter control to achieve higher reliability.(2) Design PLC program, links between theanalog variable of coolant water output temperature(。C)，the digital vairable of coolant wateroutput temperature(V), which is transferred by AID and the rfequency output(Hz)of waterpump. The purpose of design is to make them switch on ratio, to get control、compare anddisplay function; Made use of zone compairson command to solve stage control problem;Made use of TO/FROM command and special module storage to achieve convertible jfunctionbetween the analog variable of coolant water pump temperature output and digital variable ofrfequency converter output.(3) Design touch screen diagram, which included running data monitor screen, total working hours screen and command screen, it can be adjust temperaturezone and relative rfequency to control coolant water pump; Design auto mode and manualmode selection and so on.Finally, it goes through debugged process and applies to use. Evidence by8monthsoperation has been shown reliable on record since July,2013. There are including,(1) Nounstable case happens and no component failures.(2) By upgraded and before upgrade data，whichisprovided byelectric energy meter, the average of electric energy per hour saves31.11%.(3) By upgraded and before upgrade data, which isprovided by oscilloscope, theinput and output voltage graph on the converter are acceptable, harmonic and noiseare undercontrol. |
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