ASHRAE and the International Institute of Refrigeration (IIR) has established new definitions for five refrigeration keywords: cooling, refrigeration, chilling, freezing and cold chain.

The definitions are the result of more than a year of discussions, the organizations say, and were established to clarify the meaning of basic terminology used in the HVAC&R industry. 2018-2019 ASHRAE President Sheila J. Hayter, explains: 

“The new definitions will help those within our industry, as well as the general public, gain a clearer understanding of important refrigeration keywords that are often misused or too broadly defined. We appreciate the contributions of IIR and anticipate that the adoption of these definitions will be positive.”

The new official definitions for the five keywords are as follows:


  • (1) Removal of heat, usually resulting in a lower temperature and/or phase change
  • (2) Lowering temperature


  • (1) Cooling of a space, substance or system to lower and/or maintain its temperature below the ambient one (removed heat is rejected at a higher temperature)
  • (2) Artificial cooling


  • Cooling of a substance without freezing it


  • Solidification phase change of a liquid or the liquid content of a substance, usually due to cooling

Cold Chain 

  • Series of actions and equipment applied to maintain a product within a specified low-temperature range from harvest/production to consumption

IIR is urges national and regional associations to adopt and disseminate the new definitions now. The definitions will also be included in ASHRAE Terminology, its free comprehensive online glossary of more than 3,700 terms and definitions related to the built environment, with a focus on heating, ventilating, air conditioning, and refrigeration (HVAC&R), as well as building envelope, electrical, lighting, water and energy use, and measurement terms.

“It was important that the differences that might exist in these definitions between the IIR and ASHRAE be erased for more consistency. It now seems important for us to reach even greater harmonization on an international level to establish universal definitions,” says Jean-Luc Dupont, head of the Department of Scientific and Technical Information of the IIR.

For more information on the new definitions, visit