ANS:C - spray chamber

The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is the spray chamber. Explanation:

1. Adiabatic Humidification-Cooling Operation:
   • Adiabatic humidification-cooling refers to a process where the air is humidified while being cooled, without any exchange of heat with the surroundings.
   • This process is commonly used to control the temperature and humidity of air in various industrial and commercial applications, such as air conditioning systems, agricultural operations, and industrial processes.
2. Spray Chamber:
   • A spray chamber is a type of equipment used for adiabatic humidification-cooling operations.
   • In a spray chamber, liquid is atomized or sprayed into the air stream, allowing for efficient evaporation and humidification of the air.
   • The liquid used in the spray chamber is typically recirculated to ensure continuous operation and efficient use of resources.
3. Operation:
   • In the spray chamber, the liquid is sprayed into the air stream in the form of fine droplets.
   • As the droplets evaporate, they absorb heat from the surrounding air, causing the air temperature to decrease.
   • Simultaneously, the evaporation of the liquid droplets adds moisture to the air, increasing its humidity.
   • The recirculation of the liquid ensures that it can be continuously sprayed into the air stream, maintaining the desired temperature and humidity levels over time.
4. Comparison with Cooling Towers:
   • Cooling towers, both natural draft and induced draft, are primarily used for the removal of heat from water streams through evaporation.
   • While cooling towers can indirectly influence the humidity of the air by evaporating water, they are not specifically designed for adiabatic humidification-cooling operations with recirculating liquid.
   • In contrast, spray chambers are specifically designed for adiabatic humidification-cooling applications, providing efficient and controlled humidification and cooling of air using recirculating liquid.

In summary, when it comes to adiabatic humidification-cooling operations with recirculating liquid, the spray chamber is the equipment of choice due to its effectiveness in atomizing the liquid and facilitating efficient evaporation and humidification of the air.