Comments on: Building Science Term of the Week: Grains of Water https://www.energyvanguard.com/blog/building-science-term-of-the-week-grains-of-water/ Building science knowledge, HVAC design, & fun Wed, 21 Jul 2021 14:00:40 +0000 hourly 1 https://wordpress.org/?v=6.6.2 By: Paul Szymkiewicz https://www.energyvanguard.com/blog/building-science-term-of-the-week-grains-of-water/#comment-15950 Wed, 21 Jul 2021 14:00:40 +0000 https://www.energyvanguard.com/?p=6184#comment-15950 If we define our physical system as the Earth and its atmosphere for the purposes of BS, why would we worry about mass vs. weight (other than using the correct units)? Oh, I know why! In the currently very lively spirit of space exploration, we could be designing HVAC systems for a base on Mars.

]]> By: William Hullsiek https://www.energyvanguard.com/blog/building-science-term-of-the-week-grains-of-water/#comment-15941 Tue, 20 Jul 2021 23:12:12 +0000 https://www.energyvanguard.com/?p=6184#comment-15941 Would love to see an article on combining HRV/ERV with Dehumidifiers. Messana does this with their ATU and NDP units, and Build Equinox does this with their CERV2 units. But then again, I like the work of Robert Bean on Comfort Controls and Radiant Heating/Cooling. Probably my Chem Eng. training.

Need to figure out how to convert Grains into Moles…..

]]> By: Loren Amelang https://www.energyvanguard.com/blog/building-science-term-of-the-week-grains-of-water/#comment-15940 Tue, 20 Jul 2021 22:38:05 +0000 https://www.energyvanguard.com/?p=6184#comment-15940 Your correction says, “The pound is a unit of weight, so it gets a bit confusing here.”

Actually, you could have convinced me, but that statement doesn’t fit with “Whether we define the grain in terms of pounds, grams, or slugs, just remember that the grain is strictly defined as a unit of mass.”

So – Wikipedia:
https://en.wikipedia.org/wiki/Mass_versus_weight
“Similarly, the avoirdupois pound, used in both the Imperial system and U.S. customary units, is a unit of mass, and its related unit of force is the pound-force.”

Thanks for getting me to clear that up…

]]> By: Allison Bailes https://www.energyvanguard.com/blog/building-science-term-of-the-week-grains-of-water/#comment-15935 Tue, 20 Jul 2021 14:15:46 +0000 https://www.energyvanguard.com/?p=6184#comment-15935 In reply to Bob Hale.

Bob, yes, you’re correct, of course. I was sloppy in not clarifying that detail. In my days of teaching physics, I would have deducted points from my students for such sloppiness. I’ve corrected the article.

]]> By: Allison Bailes https://www.energyvanguard.com/blog/building-science-term-of-the-week-grains-of-water/#comment-15934 Tue, 20 Jul 2021 14:14:11 +0000 https://www.energyvanguard.com/?p=6184#comment-15934 In reply to RoyC.

Thanks, Roy. I was using the ASHRAE psych chart simply as a visual example, but I guess it’s good to point out that little detail. I’ve added a note to the article about your correction.

]]> By: Bob Hale https://www.energyvanguard.com/blog/building-science-term-of-the-week-grains-of-water/#comment-15867 Fri, 16 Jul 2021 20:14:42 +0000 https://www.energyvanguard.com/?p=6184#comment-15867 Strictly speaking, a grain is a unit of mass, rather than weight. It is equal to exactly 64.79891 milligrams.
Best, Bob.

]]> By: RoyC https://www.energyvanguard.com/blog/building-science-term-of-the-week-grains-of-water/#comment-15853 Thu, 15 Jul 2021 14:47:57 +0000 https://www.energyvanguard.com/?p=6184#comment-15853 As a long time member of ASHRAE and a former chair of TC1.1 (Thermodynamics and Psychrometrics), I have to correct you about the ASHRAE Psych Chart that you discussed. The vertical axis is not grains of water per pound of dry air. It is pounds of water per pound of dry air. I have ASHRAE Psych Charts going back to 1963 and have never seen one with grains/pound. I do admit that a lot of company psych charts do use grains/pound, but ASHRAE dropped that long ago.

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