Storing it from what? There is a value if you can capture additional heat that would otherwise be lost to you, like in a passive solar. Other than that, not so much.
For example, I have a high atrium which can collect heat by both direct insolation and by being in contact with the warmest air in the home. Calculations showed that an additional layer of drywall would be useful in retaining that heat.
Here is an example: Atrium Surface area ( we'll use only the upper 15 feet for simplicity); (32 X 15) + (15 X 15) = 700 sf.
700 sf X 2.5 lbs/sf (5/8 gypsum) = 1,750 lbs. (That's right, nearly a ton of extra mass)
Let's say the atrium temperature can be 88F and call it 98F to account for the extra insolation. That's 30 degrees above normal. It would be uncomfortable to have those temp differences in a standard home.
Now, you've got 1,750 lbs X 30F X .26 BTU/lb*F = 13,650 BTU. Congrats, you just captured about 15 cents worth of energy (at a COP of 3.0) for the day. And remember, I got that from passive solar. What is the benefit, other than "comfort" if your heating system puts the energy into the drywall in the first place and just allows it to trickle out over time?
BTW, this effect goes both ways. When they brought 22,000 sf of cold drywall into my build which had been comfy steady state on 2 minisplit heads running intermittently, this is what happened;
22,000 sf X 2.5 lbs/sf X 0.26 BTU/lb*F X (68F-38F) = 429,000 BTU shortfall. I had to run a 75,000 BTU torpedo for about 8 hours before temps recovered.
For a normal home, 5/8 drywall might give you the best value. You get 25% more mass for nearly no cost increase. Save the double drywall for areas in which heat can actually be captured. |