What unit of measurement are thermostatic expansion valves rated in?

Thermostatic expansion valves are rated in tons of refrigeration which is a standard unit of measurement that denotes the cooling capacity of a refrigeration system. This rating helps in understanding how much heat can be absorbed from a space to maintain a desired temperature.

The "ton" in tons of refrigeration is derived from the amount of heat absorption required to melt one ton of ice over a 24-hour period, equating to approximately 12,000 BTUs (British Thermal Units) per hour. This measurement is crucial for effectively sizing and selecting the appropriate components in a refrigeration or air conditioning system, ensuring optimal performance and efficiency.

This unit of measurement is favored in the HVAC industry because it directly relates to the cooling efficacy of the system, allowing technicians and engineers to effectively match equipment with the cooling requirements of the space being conditioned. Other options such as horsepower, cubic feet, or degrees Fahrenheit do not specifically relate to the cooling capacity of a refrigeration system in the way that tons of refrigeration do.