Automation of ventilation chambers
Ventilation control system for office premises of an investment company
An application has been received for the modernization of the existing automation system for ventilation systems using OWEN equipment. The system was previously created on several PLC63 ARIES and PLC100 ARIES. The source codes (program texts for the controllers) were not transferred to the customer. There was no documentation or marking of cable products. The system was almost uncontrollable, the equipment was constantly turning on and off randomly, while the system did not give any diagnostic messages.
We proposed replacing OWEN equipment of old models with OWEN equipment of new models with a centralized architecture: SPK107(M02), MX110 input/output modules and three PVT100 digital sensors.
Having called and signed all communication lines, we placed an order and purchased equipment.
The customer ultimately received a stably operating ventilation chamber control system with notification of ongoing system events through the OWENCLOUD service.
The supply and exhaust ventilation system consists of four independent supply ventilation systems, each of which has the ability to maintain temperatures for both heating and cooling.
A glycol cooler (a type of coolant) with an external unit is installed in the supply channel, which is turned on and off according to the need to cool the air in the channel and the cooling needs of the systems. The air cooling algorithm in the supply channel is as follows:
If one of the supply systems requires more cooled air supplied to the room, then this generates an enable signal for the air pre-cooling subsystem.
The cooling system itself operates on the principle of hysteresis (threshold control), thus maintaining the temperature in the channel in a certain range around the set value. If the owner needs to reduce the temperature, then he just needs to lower the setpoint (set) of the air in the duct. By clicking on the snowflake at the bottom of the screen, he gets to the faceplate (pop-up window) of cooling, on which he can set the required value.
The cooling system itself operates on the principle of hysteresis (threshold control), thus maintaining the temperature in the channel in a certain range around the set value. If the owner needs to reduce the temperature, then he just needs to lower the setpoint (set) of the air in the duct. By clicking on the snowflake at the bottom of the screen, he gets to the faceplate (pop-up window) of cooling, on which he can set the required value.
Humidifiers
Each supply unit contains humidifiers designed to provide air supply with the required humidity parameters. This system compares the humidity supplied to the ventilation system duct with a humidity sensor placed in the room. Thus, two sensors placed in series allow for a gradual supply of humidified air, avoiding oversaturation of humidity (<80%) in the channel immediately after the humidifier.
The humidification algorithm itself looks like this:
Each supply unit contains humidifiers designed to provide air supply with the required humidity parameters. This system compares the humidity supplied to the ventilation system duct with a humidity sensor placed in the room. Thus, two sensors placed in series allow for a gradual supply of humidified air, avoiding oversaturation of humidity (<80%) in the channel immediately after the humidifier.
The humidification algorithm itself looks like this:
When any of the air handling units is in operation, it generates permission to turn on the humidifier. However, power is supplied to the humidifier itself if the switch-on threshold drops below 5% of the set value and turns off when the humidity in the room reaches the set value and exceeds it by 5%. Power is supplied in pulses of 20s and 30s pauses, which allows you to gradually reach the desired humidity level in the room. Thus, we overcome the situation when the air duct becomes excessively waterlogged by drying it with a passing air flow.
The humidity value is set from the installation’s faceplate.
Air handling unit control algorithms:
1. Sequence of starting the air handling unit
2. Algorithm for warning and protection against freezing
3. Algorithm for maintaining the return water temperature at a given level
4. Algorithm for maintaining indoor air temperature
Air handling unit startup sequence
The startup sequence of any ventilation system is determined by the need to preserve the radiator (heater) of the system in winter. Cold air coming from the street may well be at a negative temperature, and since water flows in the radiator, there are also risks of water freezing with its expansion in the radiator tubes with subsequent damage to the radiator.
For this, the following algorithm (sequence) applies:
1. After the command to start the system is given, the return water temperature regulator opens.
2. The hot water pump turns on.
3. When the return water temperature is reached, a command is given to open the system shutters.
4. A command is given to turn on the fan motor.
5. The algorithm for stabilizing the supply air temperature at the level set from the faceplate is activated.
Algorithm for warning and protection against freezing:
1. Behind the radiator in the direction of air mass movement there is a capillary frost warning sensor, and a temperature sensor is located on the return pipe from the heater.
2. When the capillary sensor is triggered or the return water temperature drops below the set threshold, a signal is generated to stop the system and force the circulation pump to turn on. At the same time, the fan drive is turned off and the system shutters are closed.
3. Algorithm for maintaining the return water temperature at a given level.
4. For each ventilation system, a reconfigured PID controller is provided, designed to stabilize the water temperature in the heater circuit.
Algorithm for maintaining indoor air temperature:
For each ventilation system, a reconfigured PID controller is provided, designed to stabilize the air temperature in the heated air supply circuit.
1. Behind the radiator in the direction of air mass movement there is a capillary frost warning sensor, and a temperature sensor is located on the return pipe from the heater.
2. When the capillary sensor is triggered or the return water temperature drops below the set threshold, a signal is generated to stop the system and force the circulation pump to turn on. At the same time, the fan drive is turned off and the system shutters are closed.
3. Algorithm for maintaining the return water temperature at a given level.
4. For each ventilation system, a reconfigured PID controller is provided, designed to stabilize the water temperature in the heater circuit.
Algorithm for maintaining indoor air temperature:
For each ventilation system, a reconfigured PID controller is provided, designed to stabilize the air temperature in the heated air supply circuit.
#Ventilation, #Dispatching, #OWEN
Be the first to comment