h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Well. All very correct but certainly in need of editing both for spelling and clarity. Refrigerators do not use needle valves for example but rather a long very narrow piece of tubing called a capillary as the restrictor. Also, when the refrigerant leaves the restictor and enters the evaporator the change in pressure immediatly causes a portion of the liquid to covert to a vapour and thus absorb the excess heat of the liquid allowing it to drop quickly to the temperature of the evaporator and so start absorbing heat from the interior.
Another interesting point is that since this system only requires that you move the refrigerant around by compressing it, you remove more heat energy from the interior than you consume in energy to do the work. Usually in the order of three times as much, which makes this a very efficent process.
There is always talk of how electronic refigeration is on it's way in but the truth is that electronic refigeration (done with a comletely different process involving dissimilar metals) consumes more energy than it transfers. This method has been in use in submarines for many decades as it does not require a noisy compressor.
On the other hand a new process is being developed involving material that changes temperature when passed thourgh a magnetic field. Using superconducting magnets reseachers have transfered as much as 16 times the energy that they consumed. Clearly the wave of the future, air conditioning systems use the same priciples as the refrigerator and consume vast amounts of power in modern cities. Cutting that consumtion to a third would have an enormous impact.