A frugal sauna

nicksanspam · 2006-01-05T13:54:40+00:00

Vot to do with 100 watt bulbs after replacing with CFs?Maybe a sauna, with a power strip with bulb-to-prong converters and Herbachand Rademan (800) 848-8001 's $2.95 TM92HVC2293thermostat and a small vent fan and a humidistat and a few moreunswitched bulbs for reading the Sunday paper...A 4'x4'x8' room with a small window and 15 cfm of airflow has a thermalconductance of about 15+144ft^2/Rv, and the ASHRAE HOF says a warm radiantbarrier with e = 0.05 and a large air space has a thermal resistance ofabout US R3. With "R6.5" 1" double-foil polyiso board walls, (R12.5,counting foils), the room would have a conductance of 15+144/12.5 = 26.5Btu/h-F, so we could keep it 150 F in a 70 F room with (150-70)26.5 = 2120Btu/h, ie 621 watts, eg 70 watts from 1 person plus 551 from 6 100W bulbs. If a person at rest in a 70 F room makes 155 Btu/h of latent heat, ieevaporates 0.155 lb/h of water, and 15 cfm of fresh air (an ASHRAE spec)flows through the room and the humidity ratio outside the room wo = 0.00787pounds of water vapor per pound of dry air (70 F at 50% RH) and 1 ft^3 ofair weighs 0.075 lb, 60x15x0.075(wo-wi) = 0.155 lb/h makes wi = 0.0102, witha vapor pressure Pi = 29.921/(1+0.62198/wi) = 0.481 "Hg inside the room.At 150 F and 100% RH, P150 = e^(17.863-9621/(150+460)) = 8.09 "Hg, with a Clausius-Clapeyron approximation, and Pi/P150 = 0.06, so we might turn ona 50 cfm fan if the room RH ever rises to 6%. (With no extra moisture, itwould be 100x0.374/8.09 = 0.046, ie 4.6%.) I wouldn't hesitate to turn onthe fan at a higher RH, since people can safely sweat up to 4 lb/h, and withmore humidity, the room will feel equally hot at a lower air temp with lessheating energy. At 30% RH, the ASHRAE 55-2004 comfort standard predicts thatwe can lower the air temp to 142.3 F... 50% allows a 136.3 F air temp.Nick

m Ransley 20 years ago

nick we need more numbers to verify this, can you please provide complete detailed numbers, cost , cost to operate, Time to warm to temp, costs at increased utility prices, cost payback. Cost vs resistance heat, heat loss, heat output, life expectancy , cost to cook a chicken, price per hr of fun etc etc , you just dont have enough numbers. its all in the numbers, its all in the numbers.

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C. Massey 20 years ago

Geez... Lighten up!

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rick++ 20 years ago

Not relevant. Violate code and your insurance wont pay claims and your home will not sell. Not to mention a nasty fine from your county inspectors.

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RicodJour 20 years ago

If that's a pun, not bad.

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John P.. Bengi 20 years ago

How about this

10 Let Heat = desired 20 For Idiots = 1 to n 30 Gosub ReadSome 40 Gosub ReadSumore 50 Next Idiot 60 Praise writer 70 Print "You're wonderful" & Chr$(13) & Chr$(10) 80 Print "To bad you are stuck in the 60s" 90 End 100 Rem If you_can't_do then teach 110 Throw in Scott towel.

pretty image. The

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Bengi"

Nick's

officer

you

fancy.

still

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