1. Cold production: background and alternatives

1.1 Cooling: an unavoidable but energy-hungry necessity

Today, refrigeration is an indispensable part of modern society and the global economy. It is indispensable in many refrigeration and air-conditioning applications to preserve health, ensure safety and improve comfort: air conditioning, refrigeration, freezing, cooling, chilling. Without refrigeration, the food supply would remain limited to seasonal, local and non-perishable products; medical and surgical advances would have been impossible. In all sectors of industry and scientific and technological research, development would have been severely handicapped by the lack of cryogenics. Cold also brings undeniable comfort to our daily lives.

However, the production and use of refrigeration generate considerable...