Air-cooled direct expansion fresh air unit variable frequency control:
1. Temperature and humidity control, variable frequency control of the fan and compressor:
1) Use the temperature sensitive element T at the MAU outlet to control the outdoor compressor to ensure the outlet temperature Tdb=20°C (adjustable);
2) Use the dew point temperature sensitive element Tdp at the MAU outlet to control the MAU compressor, ensuring the outlet dew point temperature Tdp=17.8°C (adjustable);
3) In winter, use the internal temperature sensor T of the MAU and the external temperature sensor T to control the electric heating amount inside the unit, the compressor speed, and the four-way reversing valve, ensuring the outlet temperature T is greater than 15°C (adjustable);
2. The MAU fan operates at variable frequency, controlled by the pressure difference (5Pa adjustable) between the machine room and the corridor.
3. Fire dampers are interlocked with the fan; if any fire damper in the duct closes, the fan will stop operating.
4. The air conditioning unit is equipped with a pressure difference alarm device for easier filter replacement.
5. The electric shut-off valve for fresh air is interlocked with the air conditioning fan; when the fan is off, the electric shut-off valve closes.
6. Each MAU comes with an independent controller and electric shut-off air valve, capable of independent control and integration into the BMS control system.
7. Remote monitoring content:
1) In addition to the on-site observation device for the filter, a remote display device is also required;
2) Parameters of the air supply status point of the MAU;
3) Operating status and speed (frequency) of the MAU fan.
8. The electric air valve on the air supply duct is interlocked with the unit for opening and closing.