• • Ambient wind speed is the dominant factor: at wind speeds >8 m/s, the back pressure difference between towers exceeds 1 kPa, and the upstream tower (Tower 2) exhibits significantly larger fluctuations and reductions in air intake and heat dissipation than the downstream tower (Tower 1), directly impacting unit load and efficiency.
• • Ambient temperature primarily affects system back pressure: as temperature rises from 5°C to 34.9°C, back pressure increases from approximately 6.1 kPa to 28.2 kPa, a 4.6-fold rise that can severely constrain summer peak output.
• • Closing windward rolling shutters or reducing louver openings improves circumferential air redistribution but reduces total tower air flow and heat dissipation; the loss from the windward zone is not fully compensated by leeward gains, so such measures are not recommended under high-wind summer conditions.
• • Bottom bypass windows outperform top bypass windows: at 12 m/s wind, each 20% increase in bottom bypass opening raises heat dissipation by about 0.8%, and increasing from 70% to 100% opening yields an additional ~3% improvement; top bypass windows at 50% opening actually reduce heat dissipation by ~2.2%, so top bypass installation is discouraged.
• • NDC systems demonstrate superior economics: compared to design values, the 660 MW NDC unit reduces auxiliary power consumption rate by 1.1 percentage points, lowers net coal consumption by 4 g/(kW·h), and achieves a minimum load of 20% THA (better than the design 30% THA); annual net coal consumption is 3.37 g/(kW·h) lower than ISC and 2.61 g/(kW·h) lower than ACC systems.