Trade Groups Offer New Definitions of HVAC&R Terms

In an effort to clarify the meaning of basic terminology used by the HVAC&R industry, the International Institute of Refrigeration (IIR)  and the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) have developed new definitions of cooling, refrigeration, chilling, freezing and cold chain.

“How many ordinary people know what the term “refrigeration” really means?” wrote Kostadin Fikiin, international R&D project manager, Technical University of Sofia (Bulgaria), in the website “Certainly, the number is not very impressive! The matter is often a “terra incognita” even for those who are expected to shape the industrial, agri(aqua)cultural, food and energy policy of the future.”

How many ordinary people know what the term “refrigeration” really means?

Kostadin Filkin

Fikiin, who was part of the effort to develop the new definitions,  listed them 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.

Fikiin observed that refrigeration and cooling are often considered to mean the same, when in fact cooling “is the generic notion,” while refrigerationis “much more specific and means artificial (human-made) cooling.”

The IIR’s Science and Technology Council has endorsed these new definitions, which entered into force on February 8, 2019, he noted.

IIR, Fikiin said, “strongly recommends the newly defined terms to all its member and non-member countries for global use.” All refrigeration-related national and regional organizations and professional associations are also requested by the IIR “to adopt and disseminate these definitions, thereby ensuring their universal application and worldwide harmonization,” he added.