Dry Cooler with adiabatic pre-cooling A Dry Cooler with Adiabatic Pre-Cooling (often called a Hybrid Dry Cooler) is a highly efficient system that combines the standard operation of a dry cooler with the peak-performance benefits of evaporative cooling. It uses a minimal amount of water only when necessary to pre-cool the incoming air, allowing the unit to achieve temperatures closer to those of a full cooling tower while retaining the water-saving benefits of a dry cooler.
The term “adiabatic” refers to the process where heat is transferred through a change in humidity without a change in the total heat content of the air (i.e., no heat is added or removed by an external source). In simple terms, it’s cooling by evaporation.
How It Works: The Two Modes of Operation
The system intelligently switches between three modes based on the outdoor air temperature and the cooling demand.
1. Dry Mode (Most of the Time)
- When: When the ambient temperature is below a certain set point (e.g., below 70°F / 21°C).
- How: The adiabatic pre-cooling system is completely off. No water is used. The unit operates exactly like a standard dry cooler, rejecting heat through sensible heat transfer alone.
- Benefit: Zero water consumption for the majority of the year.
2. Adiabatic Mode (During High Ambients)
- When: When the ambient temperature rises above a set point and additional cooling capacity is needed.