What is the difference between spot coolers, portable air conditioners (“portables”) and evaporative coolers (swamp coolers)? 

Unlike air condoners, evaporative coolers contribute moisture to the environment because there is no compressor with circulating cold refrigerant to dehumidify.  Evaporative cooling is used in dry cleaners, restaurant kitchens and shops where high moisture and low operating costs are acceptable.  Air conditioners remove moisture from the environment, dry the air and improve the quality of the environment.