Abstract: The invention relates to a refrigerating or heat pumping process, as well as to an apparatus for performing this process.The apparatus comprises a toroidal cryostat, provided with first and second pipes for supplying fluid at temperature T.sub.1 from a heat source and a pipe for discharging this fluid, a paramagnetic substance support rotating in the cryostat, means for inducing a magnetic field in the cryostat, a fourth pipe for supplying fluid and a fifth pipe for discharging fluid at temperature T.sub.2 relative to a cold source. The magnetic field applied makes it possible, during the rotation of the support, to lower the temperature of the cold source and increase the temperature of the hot source.Application to refrigeration and heat pumping.