1. General

1.1 Objectives

Cooling and maintaining a system at low temperature requires the use of a thermodynamic device operating in refrigerator mode on the principle of a heat pump: the consumption of work W (in Joule) enables the transfer of a certain quantity of heat Q (in Joule) from a cold source at temperature T _F to a hot source at temperature T _C .

Applying the first and second principles of thermodynamics gives the relationship between work and heat: