A heat exchange device in a boiler that improves efficiency and saves fuel(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "economizer" in a sentence
"Everything that I've said might make it seem like I don't, but the fact is that I LOVE Stirling engines (Though I hate calling them that, since Stirling did not invent them, but rather patented the "economizer" a device that improves their efficiency)."
""economizer" to capture and recycle air that can be used as "free cooling.""
"I don't believe that there is a single hybrid in the senior parking lot of my kids 'high school that isn't either a pretend fuel economizer (like a Lexus GS450h or the hybrid Tahoe) or their mother's."