Chilled-Water Storage Air-Conditioning System Design Based On PIC And VFD

In this paper, the object of study is the water cold storage central air conditioning control system. As the name suggests, the system use the refrigerant is underground water,green environmental protection. The whole water system in a state of flow and circulation to avoid the excessive extraction of groundwater, resulting in serious consequences such as subsidence. In addition, this set of system energy consumption is the main part of the pumping and injection,this is accomplished in the night, from the macroscopic, the storage air conditioning technology, rise to balance power grid load peak shift of the role, not only can increase the service life of power supply equipment, also can give full play to the efficiency of the power plant, energy conservation and emissions reduction.In water storage air conditioning control system, inverter stepless speed regulation,control of PID parameter setting, working condition of heat source well pump is very important. The system is divided into master control room part and heat source Wells, master control room in the control device is S7-200 PLC and MM440 frequency converter. System in the process of operation, both through the USS protocol communication, PLC by the movements of the command control pump, PT100 temperature transmitter will be chilled water outlet nozzle temperature acquisition back, and sent to the PLC through the EM231 module, the analog output module EM232 the temperature data sent to the frequency converter, through comparing with the set temperature, the frequency of the inverter to convert temperature signal to change, so as to adjust the motor speed, variable flow control.The change of pipe flow leads to the change of temperature, in order to make the temperature at the appropriate speed change, need to use the PID closed-loop control technology, the main technical points is that P, I, D three parameters Settings, mainly through instruction guide function implementation. Master ark with Siemens TD200 touch-screen,written by MCGS configuration software, the human-computer interaction interface can seethe system running state and alarm information.In the heat source Wells, mainly including electrical diagram design and three kinds of working condition of pumping.In this paper, from two aspects of hardware and software of central air-conditioning control system design, the meaning of the water storage air conditioning is its low cost,safety, environmental protection, security and stability of the system run for more than a year,the company obvious effectiveness, has the very high social benefits and economic benefits...