PRESSURE INDEPENDENT TYPE VAV
THIS TYPE OF VAV IS DESIGNED TO CONTROL THE VOLUME OF AIR ENTERING INTO OCCUPIED SPACE WITHOUT BEING AFFECTED BY PRESSURE VARIATION IN THE DUCT.
✅ WORKING: IT IS EQUIPPED WITH AN AIRFLOW PROBE THAT MEASURES AND LIMITS THE AIR FLOW BETWEEN CFM RANGES THAT ARE FACTORY CALIBRATED. THE INPUT TO THE ACTUATOR CONTROLLER IS DERIVED FROM THE THERMOSTAT. ACTUATOR THROTTLES THE DAMPER JUST ENOUGH TO MEET THE COOLING LOAD.
✅ FOR EXAMPLE, IF THE ROOM TEMPERATURE HAS INCREASED BY 1°C ABOVE SET-POINT TEMPERATURE, THE THERMOSTAT CALLS FOR MORE COOLING. THE ACTUATOR CONTROLLER RECEIVES SIGNAL FROM THE THERMOSTAT TO OPEN THE DAMPER TO LET IN MORE AIR TILL THE ROOM TEMPERATURE MATCHES THE SET-POINT.
✅ THE VOLUME OF AIR ENTERING INTO THE SPACE DOES NOT DEPEND ON PRESSURE INSIDE THE DUCT. EVEN IF THE DUCT PRESSURE FLUCTUATES, THE FLOW SENSOR COMMUNICATES THIS CHANGE TO THE ACTUATOR CONTROLLER IN ORDER TO MAINTAIN A STEADY AIR FLOW TO ACHIEVE COMFORTABLE CONDITIONS IN THE OCCUPIED SPACE.
