## Aeration Blower Sizing Tool

The blower consumes about half of the total energy used in a typical wastewater treatment plant (WWTP). As a result, it is vital to get the right equipment and operation settings. You can evaluate the total energy consumption, select the right blower type and get the outlet air temperature by using the one and only blower tool. Improve your facility's energy efficiency or transform the calculation results into actionable solutions.

### Calculation details

* Media: *At this moment only air is supported. The media is considered with adiabatic and polytropic coefficents,density and molar mass.

* Flow: *Volumetic flow of the medium to considered during the calculation

* Inlet pressure: *Inlet pressure is the atmospheric pressure in case of aeration, but the calculator could consider different pressure.

* Differential pressure: *Required pressure increase. In case of aeration it could be calculated from the water depth, pressure losses of the pipes and diffusers.

* Ambient temperature: *This temperature is considered as reference for the temperature increase calculation and also used in the formula of the power calculations

* Daily average run: *By the average power consumption can be considered that the mashine does not run continously. Here shall estimate the daily average run based on the operation and maintenance circumstances.

* Efficiency: * Efficiency of the blower considered all the losses. So this efficiency contains the hydraulic losses, the mechanical and electrical losses.

The following table helps to set the efficiency:

Blower Type | Nominal Blower Efficiency % | Nominal Turndown,% of Rated Flow |
---|---|---|

Positive Displacement w/VFD | 60...45 | 50 |

Dry Screw PD w/VFD | 70...50 | 40 |

Multi Stage Centifugal | 76...50 | 60 |

Single-stage Integrally Geared Centrifugal | 80...72 | 45 |

High Speed Turbo Gearless Centrifugal | 80...72 | 50 |

* Average Consumed Power: *These value can be used for the OPEX calculation. The value consider the daily average run of the pump.

**$P_{avg} = \frac{Q_{avg} \rho_{media} \frac{R T_{in}}{M_{media}}}{ \gamma_{blower} u_{blower}}(\frac{\kappa}{\kappa-1})((\frac{p_{in} + p_{diff}}{p_{in}})^{\frac{\kappa-1}{\kappa}} -1)$**

where

$P_{avg}$ : Average power use

$Q_{avg}$ : Average actual flow at inlet conditions

$\rho_{media}$ : Denity of the media

R: Gas constant

$T_{in}$ : Inlet temperature

$M_{media}$ : Molar masss of the media

$\gamma_{blower}$ : Blower efficiency (contains hydraulic, mechanical and electrical efficiency)

$u_{blower} = \frac{T_{daily}}{24[h]}$ :where $T_{daily}$ Blower daily average use

$p_{in}$ : Blower inlet pressure

$p_{diff}$ : Blower pressure rise

$\kappa$ : Specific heat of media

* Installed power: *Based on the calculated power requirement the tool select a standard motor. This is estimation only could be different by the Vendor.

*Based on the polytropic and adiabatic path the tool calculates the outlet temerature of the medium (Outlet temerature of the media at the outlet flange). For safety consideration the higher value is represented as output.*

**Outlet temperature:****Isentropic case :**

**$T_{outi} = T_{in} (1 + \frac{(\frac{p_{in} + p_{diff}}{p_{in}})^{\frac{\kappa-1}{\kappa}}}{\gamma_{blower}})$**

**Polytropic case :**

**$T_{outp} = T_{in} (\frac{(\frac{p_{in} + p_{diff}}{p_{in}})^{\frac{n-1}{n}}}{\gamma_{blower}})$**

where

n: Polytropic heat capacity of the media

**$T_{out} = max(T_{outi}, T_{outp})$**

- Simon Judd: the MBR Book Second Edition
- https://powerzone.com/resources/glossary/compressorsfansblowers
- http://www.jmcampbell.com/tip-of-the-month/2011/11/compressor-calculations-rigorous-using-equation-of-state-vs-shortcut-method/
- https://www.wef.org/globalassets/assets-wef/3---resources/online-education/webcasts/presentation-handouts/19nov20-webcast-handouts.pdf