7. Other refrigeration technologies

We can turn to other existing or developing alternatives.

• Absorption

  This is a chemical refrigeration process using two liquids, an absorber, a boiler and a condenser. In turn, the solution (e.g. water + ammonia) is depleted of refrigerant by heat extraction, and must then be reconcentrated.

  Absorption systems have been in use since the advent of artificial cooling around 1850 (water + ammonia mixture) with Ferdinand Carré's machines, and around 1940 with water + lithium bromide mixture.

• Adsorption

  In this case, the couple is a state-changing fluid and an adsorbent solid (e.g. zeolite) that needs to be regenerated by heating.

• Magnetic cooling...