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New to Commercial HVAC Mechanical Design?

By Jeff Love, EIT

If you just started an engineering or consulting job in commercial building mechanical design, you may have been in a meeting that soon had you questioning what language was being spoken. Maybe you heard:

“What is the expected CFM needed for this system? Have we calculated the SP yet? I think it would be best to use the QMX model for the exhaust, but what about adding a bypass? Does this need to be an N+1 design?”

It doesn’t take long to learn the acronyms, product models, differences between manufacturers, and challenges you may routinely face during the design process. I wish I could give more firsthand accounts because I’m quite sure a hospital versus a fast-food restaurant design each can lead to quite unusual and completely different situations. Kitchen exhaust and grease, anyone? HEPA filters in the air stream? Sure. Most manufacturers offer competing product models, they each tout why one should be selected over the other. Is it perceived quality, ease of use, ease of installation, weight, rigidity, standard features, history, availability, or even “just the way it looks”? Yes, I’m calling you out my friendly architects! Do not fret though, I grew up in Columbus, IN. If you are an architect, you may be impressed. If you are an engineer, you may be thinking, “Why did he share that?!?”. Look it up. In the end, all this gibberish will start making sense and your designs will soon get you an award, even if it’s just for participation <wink>.

“For this room we need 20,000 MBH, 90-degree LAT, and 10 FPI. We should also consider adding an attenuator.”

Here we go again. I think I’d be better off talking about how awesome Baby Yoda is or maybe add some trivia in about doing the Kessel run in 12 parsecs… Too much? Of course not, you are still reading.

Yes, how about those VAV boxes? Have you figured those out yet? Variable Air Volume boxes or Terminal Units. I don’t know, terminal units sound a bit deadly, I’ll stick with VAVs. See, that’s not too hard. Then again, are you heating the air? Just moving it? To coil or not to coil, that is the question. There are many, many options in the world of VAVs, so do not be disheartened. Analog, Pneumatic, Series, Parallel, Single duct, Dual duct, Fan Powered, I have a lot to discuss in the future.

More to come. Live long and prosper! Am I allowed to say that after referencing Star Wars?

Jeff Love is the Marketing Engineer with Langendorf Supply Co. - Indianapolis. Keep watch for more interesting articles that will dive a little deeper into many of these topics.

Until then here are some helpful links:


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