Limitations of Adiabatic cooling tower at Extreme High Temperatures
Even an adiabatic system has its limits, which are defined by meteorology. The Wet-Bulb Limit: The adiabatic pre-cooling process can only cool the air down to
- the ambient wet-bulb temperature. This is a thermodynamic limit.
- Scenario: On an extremely hot and humid day (e.g., 40°C / 104°F with high humidity), the wet-bulb temperature might still be very high (e.g., 30°C / 86°F).
- Result: The adiabatic cooler will be operating, but its cooling capacity will be reduced because the pre-cooled air is still relatively warm. The system will be running at 100% capacity (fans at full speed, pumps on) but may not be able to achieve the desired process fluid outlet temperature.
Consequences of Inadequate Cooling
If the ambient temperature is too high for the system’s capacity, several operational issues can occur:
- High Process Temperature Alarm: The fluid returning to the process (e.g., condenser water to a chiller) will be too warm.
- Process Shutdown: Critical equipment (e.g., a chiller, laser, server bank) may overhear and shut down on a high-pressure or high-temperature safety fault, halting production or comfort cooling.
Reduced Efficiency of Downstream Equipment: A chiller, for example, will run very inefficiently if its condenser water temperature is elevated, causing a spike in overall facility energy use.