2.5 Measurement of Outflow the air outflow is calculated by the VMA having used itself two parameters: the area of the box (area of the section of the box where if locates the crosspiece of measurement of pressure? pickup of air) and characteristic factor K of the box (pickup gain or supply pickup gain). With these information, the VMA calculates the air outflow from the reading of pressure gotten in pickup of air, using itself it following equation 3: Where: Air outflow = Calculated in m3/h or l/s, depending on the used coefficient of outflow Coefficient of outflow = Constant of adimensio-nalizao of the equation. To the level of the sea it is equal 4644 for outflow in m3/h and 1290 for outflow in l/s Factor K = Pickup Gain (profit of pickup). Characteristic adimensional constant of each box VAV. It is not the loss of load of the measurement crosspiece, as erroneamente it is divulged. Delta P = distinguishing Pressure in Paschal.
The crosspiece of measurement of box VAV has a section of measurement in the direction the opposite to the air flow (ram pressure) and one another section directed toward the same felt of the flow (static pressure). The value that interests in them for the calculation of outflow is the difference enters du them measurements (speed pressure). 2,6 Logics of Diverse Applications the VMA operates in diverse ways. Some ways occur under normal conditions of operation and some are commanded only by a supervisory system. The way of operation of box VAV determines which loops of control PID is active. The occupation way determines the current state of occupation of the environment. Statuses of pressure of speed and temperature of the zone determine the proper functioning of the 3 VMA. 2,7 Parameters of readings; The unit of reading of the sensor of pressure in the programs of controllers VAV is? count of column d? water (In Wg)? , differently of the VMA that presents reading of pressure in? Paschal (Par).