Electric Compressors are a motor like with pipes coming out and with a coil and oil on the bottom of the compressor. Now a air compressor is different, it compresses air to inflate your tire, or pool acceriories.
A refridgeration compressor is black, and in different sizes. Now, it works once you have a evaporator coil, and a condensing coil, is like freon on your air conditioning system, frigorator, or a ice maker. In sizes, some of them are small, some are large, and it has pipes coming out to refrigerate, and condense the coils in you ac system or refridgorator.
Air compressors are different they compress air to inflate tires or any thing. Its a used a tool too.