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Posted by W on May 27, 2009, 3:08 pm
If an attic fan is properly sized, and properly installed, what should be
the temperature differential between the outside air temperature and the
attic temperature, while the fan is running?
Assume there is plentiful air intake in the attic from outside air.
--
W
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Posted by Chosen One on May 27, 2009, 3:23 pm
> If an attic fan is properly sized, and properly installed, what should be
> the temperature differential between the outside air temperature and the
> attic temperature, while the fan is running?
> Assume there is plentiful air intake in the attic from outside air.
> --
> W
After your last post what makes you think.......?
http://tinyurl.com/o27sfo
co
"I have been called bad before. Many have said I do things that are not
correct to do. I don't believe in talk such as this. I am nice man, with
happy feelings. All of the time. First, a joke. What do you get when you
cross an owl with a bungee cord?
[pause] My ass. Nyah, haha, haha, haha, ENOUGH!"
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Posted by W on May 27, 2009, 3:34 pm
Attic temperature depends on the amount of solar radiation, construction
details and the rate of ventilation. Calculations indicate that on a July
day in Texas, a ventilation rate of one air change per minute for a typical
attic using 95-degree F air will lower the peak attic temperature to about
101 degrees F. Providing half air change per minute will lower the
temperature to about 106 degrees F. Thus, the first half change per minute
is most effective and a doubling of this rate only achieves about 5 degrees
F additional cooling. Studies indicate that further increases in ventilation
are not effective in significantly reducing attic temperatures.
Calculate the required summer ventilation rate by determining the volume of
attic space and dividing by 2. This will be the cfm (cubic feet per minute)
of ventilation air needed. The volume is determined approximately for a
rectangular house by multiplying the height from the ceiling to the
peak/ridge (H) times the width of the house (W) times the length (L) and
dividing by 2 -- ( H x W x L / 2 ). For a gable roof, this will be
reasonably accurate. For a hip roof house, the volume will be overestimated
but adequate.
--
W
> If an attic fan is properly sized, and properly installed, what should be
> the temperature differential between the outside air temperature and the
> attic temperature, while the fan is running?
> Assume there is plentiful air intake in the attic from outside air.
> --
> W
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Posted by gord on May 27, 2009, 4:33 pm
> Attic temperature depends on the amount of solar radiation, construction
> details and the rate of ventilation. Calculations indicate that on a July
> day in Texas, a ventilation rate of one air change per minute for a
> typical
> attic using 95-degree F air will lower the peak attic temperature to about
> 101 degrees F. Providing half air change per minute will lower the
> temperature to about 106 degrees F. Thus, the first half change per minute
> is most effective and a doubling of this rate only achieves about 5
> degrees
> F additional cooling. Studies indicate that further increases in
> ventilation
> are not effective in significantly reducing attic temperatures.
> Calculate the required summer ventilation rate by determining the volume
> of
> attic space and dividing by 2. This will be the cfm (cubic feet per
> minute)
> of ventilation air needed. The volume is determined approximately for a
> rectangular house by multiplying the height from the ceiling to the
> peak/ridge (H) times the width of the house (W) times the length (L) and
> dividing by 2 -- ( H x W x L / 2 ). For a gable roof, this will be
> reasonably accurate. For a hip roof house, the volume will be
> overestimated
> but adequate.
> --
> W
>> If an attic fan is properly sized, and properly installed, what should be
>> the temperature differential between the outside air temperature and the
>> attic temperature, while the fan is running?
>> Assume there is plentiful air intake in the attic from outside air.
>> --
>> W
Could you convert that to BTU's so that we can understand. Thanks.
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Posted by HVAC on May 27, 2009, 7:37 pm
> Attic temperature depends on the amount of solar radiation, construction
> details and the rate of ventilation. Calculations indicate that on a July
> day in Texas, a ventilation rate of one air change per minute for a
> typical
> attic using 95-degree F air will lower the peak attic temperature to about
> 101 degrees F. Providing half air change per minute will lower the
> temperature to about 106 degrees F. Thus, the first half change per minute
> is most effective and a doubling of this rate only achieves about 5
> degrees
> F additional cooling. Studies indicate that further increases in
> ventilation
> are not effective in significantly reducing attic temperatures.
> Calculate the required summer ventilation rate by determining the volume
> of
> attic space and dividing by 2. This will be the cfm (cubic feet per
> minute)
> of ventilation air needed. The volume is determined approximately for a
> rectangular house by multiplying the height from the ceiling to the
> peak/ridge (H) times the width of the house (W) times the length (L) and
> dividing by 2 -- ( H x W x L / 2 ). For a gable roof, this will be
> reasonably accurate. For a hip roof house, the volume will be
> overestimated
> but adequate.
Why don't you just stick your dick in the fan?
A warm day at home will seem pleasant by comparison.
--
Build a fire for a man, he's warm for a day.
*Set* a man on fire, he's warm for the rest of his life.
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> the temperature differential between the outside air temperature and the
> attic temperature, while the fan is running?
> Assume there is plentiful air intake in the attic from outside air.
> --
> W