heat exchanger vs device

heat exchanger and device both are nouns.

Word	Noun	Adjective	Verb	Adverb
heat exchanger	Yes	No	No	No
device	Yes	No	No	No

As nouns, device is a hypernym of heat exchanger; that is, device is a word with a broader meaning than heat exchanger:

heat exchanger: device that transfers heat from one liquid to another without allowing them to mix
device: an instrumentality invented for a particular purpose

heat exchanger (noun)	device (noun)
device that transfers heat from one liquid to another without allowing them to mix	any clever maneuver
	an instrumentality invented for a particular purpose
	an emblematic design (especially in heraldry)
	any ornamental pattern or design (as in embroidery)
	something in an artistic work designed to achieve a particular effect