cooling vs cooling system

cooling and cooling system both are nouns.

Word	Noun	Adjective	Verb	Adverb
cooling	Yes	No	No	No
cooling system	Yes	No	No	No

As nouns, cooling and cooling system are synonyms defined as:

cooling (noun)	cooling system (noun)
a mechanism for keeping something cool	a mechanism for keeping something cool
the process of becoming cooler; a falling temperature	equipment in a motor vehicle that cools the engine