Calculation formulas - Basic Documentation - GDB181.1E/BA - GDB181.1EMBA - GLB181.1E/BA

VAV Compact Controller BACnet MS/TP G..B181.1E/BA

Product Family
OpenAir
Product Group
Damper actuators
Content Language
English
Content Type
Basic Documentation
Product Version
Status
Valid
Date
2021-10-26
Document No
A6V10631864_en--_g
A6V10695831
Stock No.
S55499-D168
S55499-D169
S55499-D506
Product No.
GDB181.1E/BA
GDB181.1EMBA
GLB181.1E/BA

The parameters are based on the following formulas:

Calculation of Vn
(Δpnom = nominal pressure)

$$V_{n} = \sqrt{\frac{300\ \lbrack Pa\rbrack}{\mathrm{\Delta}p_{\text{nom}}\lbrack Pa\rbrack\ }}$$

300 Pa is the upper limit of the operating range of the differential pressure sensor. The nominal pressure is the differential pressure in the VAV box at a given nominal volume flow, determined by the OEM specification.

Min. and max. volume flows (Vmin / Vmax)

$$V_{\min}\lbrack\%\rbrack = \frac{min.\ \ volume\ flow\ \lbrack\frac{m^{3}}{h}\rbrack}{nom.\ \ volume\ flow\ \lbrack\frac{m^{3}}{h}\rbrack} \bullet 100\%$$

$$V_{\max}\lbrack\%\rbrack = \frac{max.\ \ volume\ flow\ \lbrack\frac{m^{3}}{h}\rbrack}{nom.\ \ volume\ flow\ \lbrack\frac{m^{3}}{h}\rbrack} \bullet 100\%$$

Actual relative flow as function of setpoint and min. / max. limits

$\text{FLW\ }\lbrack\%\rbrack = \frac{\text{Setpoint\ }\lbrack\%\rbrack \bullet \left( V_{\max} - V_{\min} \right)\ \lbrack\%\rbrack}{100\%} + V_{\min}\ \lbrack\%\rbrack$

Actual relative flow as function of differential pressure

$$\text{FLW\ }\lbrack\%\rbrack = 100\% \bullet V_{n} \bullet \sqrt{\frac{\mathrm{\Delta}p\left\lbrack \text{Pa} \right\rbrack}{300\left\lbrack \text{Pa} \right\rbrack}}$$

Actual differential pressure as function of actual flow

$$\mathrm{\Delta}p\left\lbrack \text{Pa} \right\rbrack = 300\ Pa \bullet \left( \frac{\text{FLW}\lbrack\%\rbrack}{100\% \bullet V_{n}} \right)^{2}$$