What is the air conditioning control system? How does the air conditioning control system work?

At this stage, in the process of management and control of HVAC control systems, the effective application of automated central air conditioning control systems has played an important role in reducing energy consumption, improving system operation quality, and strengthening management and labor intensity. This paper mainly introduces the application of the automatic control system of the central air-conditioning control system. The paper first introduces the automatic control technology in the central air-conditioning system, and then analyzes the application of the intelligent control technology, in the hope that it can be related to the later stage. Work has guidance.

At present, with the continuous development of science and technology, the application of central air-conditioning control systems is becoming more and more extensive, and it has been invested in the indoor temperature adjustment process of some large buildings such as high-grade office buildings and work factories. At the same time, due to the continuous maturity of automation and intelligent control technology, automatic control technology has gradually been introduced into the central air conditioning control and regulation system, which not only provides people with a more comfortable working and living environment, but also saves Operating costs and extending the life of the central air conditioning control system have also shown great value.

1 Automatic control technology in central air conditioning control system

1.1 Adjustment of cold heat source and water pipe system

For the host system of the central air conditioning control system, its own unit controller can provide a number of index factors such as the inlet and outlet temperatures of the condenser and evaporator and the pressure of the water flow switch compressor. In this process, the system is mainly a group control mode, which achieves the automatic control of the heat pump, and also plays a good function of monitoring, query and alarm.

In the event of a fault in the normal operation of the unit, the system main controller will immediately display the corresponding alarm and issue an alarm; in addition, it can adjust and change the relevant values ​​set by the system. For example, at different times of the day, such as evening and daytime, there are large differences in the values ​​set by the system. For the system compressor combined with the relevant commands, refer to the set value of the freezer room outlet to adjust the compressor inlet guide vane valve. In this process, the outlet temperature of the chilled water can also be set, and the running state of the host can be monitored in real time by the water flow sensor and the temperature sensor.

1.2 Parameter measurement of fresh air and air conditioning units

In order to better improve indoor air cleanliness and freshness as well as indoor comfort, a central air conditioning control system is required to replenish fresh air in a timely manner. Under normal circumstances, the temperature and proper sensor installation are required at the position of the air supply passage of the fresh air air conditioner unit, and the flow rate is effectively controlled by the application of the humidification method, thereby better meeting the design requirements. The central air-conditioning system can also combine the indoor temperature and moderate calculation load to complete the self-replacement of the windshield, and thus successfully realize the effective control of the air supply volume. In addition, the central air-conditioning control system can also adjust the opening degree of the damper in combination with the indoor and outdoor temperature and humidity as well as the predetermined temperature and humidity of the system, and implement a linkage control of the exhaust valve, thereby achieving a power saving effect.

The fresh air valve and the exhaust valve will be in a closed state after the unit stops running. At this time, the return air valve should be kept fully open, and the DOC controller can be realized for the automatic control of the central air conditioning system. In the practice process, combined with the fresh air temperature, the water valve is adjusted by PID, which effectively ensures the air supply to a predetermined value. At the same time, by controlling the steam valve and the humidifying valve, the air temperature at the outlet of the wind turbine in winter is guaranteed. Moreover, the system can also monitor the temperature and humidity of the fan outlet and the pressure difference between the two sides of the fresh air filter in real time. Once these values ​​are abnormal, the system will automatically alarm.

1.3 Monitoring of fan coils in central air conditioning systems

The heating and cooling equipment in the central air conditioning system is mainly composed of air conditioning units, new air units and a large number of fan coils. Among them, the fan coil is currently mainly used by the DOC controller and the controller with communication capability; the DOC controller has the communication function with the system host, which can control the cold machine and the cold water well. The control market price is generally higher; and the coil controller with communication capability recommends that the fan coils be grouped according to the connection of the water system during the application process, and the flow meter is performed on the inlet side of each group of branches. Installation of water temperature sensor and water pressure transmitter.

At present, in the process of automatic control of the central air-conditioning control system, it is impossible to completely rely on the DOC technology for control. Therefore, in the process of cooling effect control and air volume debugging of the system, it is impossible to apply the automatic adjustment function of various types of dampers to achieve Uniform airflow design requirements. For such problems, the more commonly used method is the "reference air outlet method", that is, the manual adjustment of the air volume.

2 Application of intelligent control technology

Take a hotel as an example. A total of three cooling water pumps were installed in the hotel, and the motor capacity and load factor were 65 kW and 90%, respectively. In the central air-conditioning system, the lower-level machine is used as the monitoring software for the S7-300 PLC and the upper computer, and the energy-saving of the central air-conditioning inverter is shown.

In this case, the central air conditioning control technology mainly applies two intelligent control technologies: fuzzy control technology and neural network control technology; among them, fuzzy control technology realizes effective control of some unstructured models through simulation of human thinking; Based on the RF technology and PLC application, the application of the fuzzy controller can achieve a more significant effect than the traditional PID control mode.

2.1 Application of automatic control system in constant air volume air conditioning system

During the operation of the fixed air volume system, once the air volume is determined, the fan maintains a full air volume operation regardless of the load change, and the change of the supply air temperature also satisfies the change demand of the indoor cold heat load. Better to keep the room in an optimal temperature and humidity state. The general central control system not only needs basic heating, heating and dehumidification functions, but also intelligently controls the components such as the system exhaust vents, electric dampers and return fans, thus realizing the cycle automation of the control system. Therefore, a good control effect can also be obtained. In the automatic control system of the fixed air volume air conditioning system, the focus of its work is on the management and control of the air conditioning temperature and humidity adjustment and the application ratio of the exhaust valve, fresh air valve and return air valve.

2.2 The effective application of automatic control in variable air volume air conditioning system

During the operation of the variable air volume system, when the indoor cold and heat load changes, the change of the supply air temperature is not caused, and only the air volume is changed, thereby maintaining the indoor temperature and humidity well. The system is equipped with an automatic control damper at the air inlet location of each room. In the process of its application, the control of the air supply volume and the adjustment of the temperature and humidity of each room are achieved. A major feature of the variable air volume control system is that the supply air temperature is kept constant, that is, the opening of the recovery regulator valve of the air cooler remains unchanged.

In short, the effective application of the automatic control system in the central air conditioner has exerted great application value, which not only achieves a good effect of energy saving and consumption reduction, but also significantly improves the control efficiency of the system. Therefore, the application prospect of the automatic control system in the central air conditioning system is also very broad.

The above is a detailed answer to the application of the automatic control technology in the central air-conditioning system. I don't know if you are satisfied with the introduction of the decoration home network. If you want to know more about the exciting content, please continue to pay attention to our decoration encyclopedia!