Air Cooled Condenser Challenges
Wind Shear and Loss of Airflow
Crosswinds have a detrimental impact on the performance of your ACC. As air collides with the wind walls it accelerates underneath the fans causing wind shear. This causes some immediate challenges – airflow reduction, changes in fan static pressure, and dynamic fan blade loading. Increases of windspeed by just 5m/s can equate to a 30% reduction in airflow.
Decline in Thermal Performance
Airflow reduction and wind shear can cause fan trips, fan stalls and increases in vacuum which all lead to plant derate and an overall decline in power output. In case studies we have shown that 20% of airflow reduction has equated to a 33% increase in back pressure.
Accelerated winds underneath the fans cause significant changes in fan static pressure in and around the fan housing or cylinder. This exerts huge pressure forces on the fans creating fan imbalance and damage. It has been estimated that 75% of fan imbalance is due to the wind.
Fan Blade Damage
High crosswind conditions can lead to significant mechanical stress causing premature failures on blades and fan hardware. Gear reducer failure and motor trips are also common symptoms of vibration or motor amperage overloads due to uneven fan performance. It has been estimated that 80% of motor vibrations are due to the wind.
The interaction of high wind speeds with hot air plumes from the ACC structure generate complex vortices which can re-circulate hot air back into the fans. This increases the air inlet temperature, reducing cooling capacity and thermal performance.