We as human thrive in all kinds of climates and we can control the quality of the air in the enclosed spaces in which we live. The use of mechanical systems to achieve control in such places as homes, offices, theaters, institutions, factories, airplanes and automobiles is what is referred to as air conditioning. The most familiar type of air conditioning is summer time cooling. Although important, this is but one of the several aspects of air conditioning. Other applications include the control of humidity (air moisture), circulation of the air, and heating. It is also desirable that an air conditioner remove dust, pollen, smoke and odors from the air.