Lower-energy winter humidification


A 2400 ft^2 x 8' tall house with 0.5 ACH leaks 160 cfm. At 30% RH and 70 F, Pa = 0.3e^(17.863-9621/(70+460)) = 0.225 "Hg and wa = 0.62198/(29.921/Pa-1) = 0.00470 pounds of water per pound of dry air. Outdoor air has wo = 0.0025 in Phila in January. Air weighs about 0.075 lb/ft^3, so keeping a house at 30% RH requires evaporating 60x160x0.075(wa-wo) = 1.584 pounds of water per hour, which requires about 1584 Btu/h, ie 38016 Btu/day, about 11.1 kWh or $1.11 per day at 10 cents/kWh, with electric heat.
As an alternative, we might use the earth's heat to evaporate water from a basement floorslab and move humid air up into the house as needed. The deep ground temp in Phila is 54.3 F. If the air near the slab is 54.3 F with 60% RH (not higher, to avoid mold) and wb = 0.00541, we might move 1.584/(60(wb-wa)) = 37 cfm of basement air up at an energy cost of about 37(70-55) = 558 Btu/h, ie 35% of the heat energy needed above.
Or maybe less, since humid air diffuses and rises, so some cool water vapor will move upstairs without moving any cool air with a fan and a duct near the floor. We might dampen the floorslab with a soaker hose and solenoid valve whenever the house is less than 40% RH and the slab is less than 60%, and only turn on the fan when the house RH drops to 30%.
Solenoid valves can be scrounged from discarded dishwashers and washing machines. Herbach and Rademan (800) 848-8001 http://www.herbach.com sells nice $4.95 Navy surplus humidistats, item number TM89HVC5203, with a 20-80% range, a 3-6% differential, and a 7.5A 125V switch that can be wired to open or close on humidity rise.
Nick
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Yep! I will get right on ripping out the carpet in my finished basement so I can soak the floor down when needed. On second though, I think I will stick with my duct mounted Aprilaire with outdoor reset. For some reason it seems more practical! Greg
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greet ideer nicko I can have a basmnt tha smeels like outsides and can get all my fishn bate for free with alldem bugs thal come a livin. Mite be a nice colur too green n mossy and a bit a blak molde. Shud be no probleem fo da furnase an watre heetre on da floo a bit a rust is no biggy am give me reesen to cleen tha room gee i thunk about putting a garden spreyar in the hoose or jusyt lettn the tub flow ova , but this is way way betta. electricity shood be no proplem I got fusses so i won get shocked, yea nikker great ideer
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Nobody missed anything Nick avec spam, this is just one case in many where you just miss the boat, like it sank to the bottom fast with you in it. I bet you don't even live in a house or control your own utility bills, so many of your ideas and comments are truly impractical, and prove a lack of understanding present reality.
So have you tried this in your house, of course not, what house. Well give it a try anyway wherever you live, tell them Its Saving Money before you are evicted ol nick, and let us know how that 12000 hr original oil test goes on all your motors.
Come back and post when you have something intelligent to say, and learn to read before you misquote people again.
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Sure brochitis, now tell me what it means.
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Can you say "B-R-O-C-H-I-T-I-S"?

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snipped-for-privacy@ece.villanova.edu wrote:

My granny used to put a pot of water on top of the space heater. Didn't cost nothing.
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Well Nick, if you remove all the calculations (I have no idea why they are there), you are left with a switch, a couple of solenoids, a fan, a garden hose and the ugliest basement in town. By the way you are still missing quite a few parts. Most people go to great lengths to keep water out for good reason. What about the underside of the floor and the attached basement ceiling??? There will be mold everywhere and you KNOW how much home buyers love mold. Sounds like a great way to save a few dollars on electricity and lose a large sum of money on your home. Please don't tell me the acedemia at Villanova have come up with this one!......Good Luck, you'll need it, Ross
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Your granny was wasting her time and kidding everybody else.
If she filled it up every 20 minutes then it may have done something but. Furnace humidifiers can put 50-100+ litres of water into the air per day to keep up. A pan of water isn't worth the spill danger. also... It also does cost something. It takes calories or BTUs of heat to evaporate the water.
http://www.highqproducts.com/tech.php
Here are some 12 gal per day units http://www.allergybuyersclubshopping.com/warm-cool-mist-humidifiers.html
wrote:

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Yup. The slab will be soaking wet at "60% RH to avoid mold"....LOL
What was that you beeked off with again? You're just here with nothing to add and are totally ignorant of the laws of physics?

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