Here's why:

* Very Cold Liquids: Refrigerants are liquids that have a very low boiling point. This means they can easily evaporate and absorb heat from their surroundings.

* Absorb Heat: When a refrigerant evaporates, it absorbs heat from the air or the substance it's cooling. This process is called evaporative cooling.

Common examples of inventions using refrigerants:

* Refrigerators: The most common use of refrigerants is in refrigerators and freezers. They work by circulating the refrigerant through a system of coils and evaporating it in a closed loop.

* Air Conditioners: Similar to refrigerators, air conditioners use refrigerants to cool air in buildings and vehicles.

* Heat Pumps: These devices can both heat and cool a space by utilizing the heat absorbed by the refrigerant during the cooling cycle.

Important Note: Many refrigerants used in the past were harmful to the environment. Newer, more eco-friendly refrigerants are now widely used.