A Study on the Application of Controller in the Rack Cooling System

• Main Authors: Yu-Feng Peng, 彭鈺峰
• Other Authors: 李魁鵬
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/77q9bd

碩士 === 國立臺北科技大學 === 能源與冷凍空調工程系碩士班 === 99 === This study aims on the application of Programmable Logic Controller (PLC) associates with PID control on Rack Cooling system. In order to achieve the target point accurately, steadily and faster, the controller is designed based on the variation characteristic between the superheated temperature set point and the actual superheated temperature. The rack cooling system is a closed loop (In-Row) system. The IT equipment cooling load in the rack is simulated by electric heater, which can be removed by the rack cooling system if IT rack is tied with cooling system rack. This research used the PLC controller to monitor the operating parameters and pass the parameter values to the computer. Once the optimum PID parameters were calculated by computer program, the control signal was sent back to the PLC for the optimum superheat control of electronic expansion valve of the evaporator. In the research, Power Usage Effectiveness (PUE) was used to evaluate the optimum operating point of the cooling system for different condenser water temperature and cooling load for the sake of energy saving. The results show that the PUE could be 1.47 at maximum cooling load point, and 1.42 at lower cooling water temperature. This maximum PUE is much better than the average PUE 1.9 of the surveyed data in Taiwan and also better than the PUE 1.52 of ASHRAE for a 300RT cooling system.