TLT Turbo Tech Talk 101 – Efficiency of Larger Fans versus Secondary Fans in Primary Ventilation Bulkhead Installation.

Efficiency / Power Comparison for small mine primary ventilation requirements of 2m Axial Fan/s versus 110kw Secondary Fans.

The specific ventilation requirements of numerous smaller mine operations getting under way during this time can be achieved by various ways. In general bulkhead installed fans are used with either single or twin larger axial fans and alternately utilising multiple secondary fans. Each method having an impact on capital, lead-time, efficiency / power, fan performance and operation. Consideration here could also be given to VSD operation to meet ramping up ventilation needs after fan/s installation, while optimising power savings.

To show how each method impacts on efficiency and power, the illustration shows performance curves (below) of a 2metre diameter Axial Fan in single and 2 fan parallel operation, along with Single and Twin Secondary Fans shown in single and multiple numbers in parallel.

Note – This example shows efficiency/power difference only and does not make any allowance for ‘Hagen Line’ effect or multiple fan starting instability which will have an impact on actual performance of multiple fans. For further information on Hagen Line and starting instability of multiple fans, please feel free to contact TLT Turbo.

A typical example of duty requirements of 190m3/s air flow @ 1,798Pa Total Pressure with the mine system resistance line is shown crossing?the various fan curves in operation. The fan efficiency and power consumed will be determined by this intersection point of the mine system line across the fan performance curves. See below each example of power and efficiency for the 2m fan, single and twin secondary fans in parallel using interpolated data, showing power draw and approximated operating costs.