What does chilled water refer to in the context of air conditioning?

Chilled water in the context of air conditioning refers specifically to a system in which water is chilled and circulated to remove heat from the air. This process is an integral part of many commercial and industrial air conditioning systems.

In a chilled water system, water is cooled to a lower temperature, typically by a chiller, and then circulated through pipes to air handling units or fan-coil units throughout a building. As warm air from the space passes over these chilled coils, it loses heat, causing the air to cool before it is redistributed back into the environment. This method is highly efficient for managing indoor climates, particularly in larger facilities where centralized cooling is necessary.

The other options do not accurately encapsulate what chilled water refers to in this context. For example, using open windows to cool air is a passive cooling method that does not involve chilling water, while a thermal barrier relates to insulation, and heating water for domestic use is unrelated to the concept of chilled water systems in air conditioning.