OT Which direction is your ceiling fan SUPPOSED to run?

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On Fri, 04 Jul 2014 16:23:44 -0400, Stormin Mormon

As John Candy would say... "They blowed up *REAL GOOD*."
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On Fri, 04 Jul 2014 21:33:06 -0400, snipped-for-privacy@attt.bizz Gave us:

Higher and more often gun maint program. Can't let the sweaty little bastard get rusty.
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On Fri, 04 Jul 2014 22:18:11 -0400, snipped-for-privacy@snyder.on.ca Gave us:

But what idiot in their right mind, especially in greater SF would buy or use such a cheap POS in a perm install?
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wrote:

From New York: <http://whiteroofproject.org/about/mission/ A roof covered with solar-reflective white paint reflects up to 90% of sunlight as opposed to the 20% reflected by a traditional black roof. On a 90°F day, a black roof can be up to 180°F while a white roof stays a cool 100°F reducing cooling costs up to 40 percent.
The problem is that the temperature of the roof only tells part of the story. If the ceiling area was super insulated, the indoor temperature would be independent of the roof temperature. Kinda looks like this is based on the assumption that some of the roof heat is conducted into the building interior. That works, but I suspect varies radically with building construction and ceiling insulation.
The advantage of a black roof might be because black radiates heat better than white. The black roof might be hotter during the day, but as soon as the sun goes down, a black roof will cool down quicker than a white roof. That might affect the average.
More: <http://whiteroofproject.org/research/scientific-data/ <http://whiteroofproject.org/research/urban-heat-islands/ <http://en.wikipedia.org/wiki/White_roof> <http://www.globalcoolcities.org <http://www.nyc.gov/html/coolroofs Unscientific anecdotal drivel: My office building was blessed with a shiny new white roof in Oct 2013. It was previously black asphalt and a thin layer of fine gray rock. It seems much cooler inside this summer, but I have no measurements to prove it.
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Jeff Liebermann snipped-for-privacy@cruzio.com
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Depends a bit. If the cooling coil is kept only a little below room temperature and you depend on sheer volume for heat transfer, you may not condense much water compared to having a sub-zero cooling coil and lower air volumes.
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On 7/4/2014 11:45 PM, Ralph Barone wrote:

So are you saying a heat pump can change the laws of physics, but just a little bit? Thanks, I must have missed that class.
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Not at all. You're welcome.
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On 7/5/2014 8:46 AM, Ed Pawlowski wrote:

I think Ralph's point is moot because AC units don't cool "only a little below room temperature", but the concept is valid. Moisture condenses only when cooled below the dew point. It doesn't even depend on the temperature of the coil, but rather of the air passing over the coil. If the air never reaches the dew point (either because the coil is not that cold or because the air moves over the coil so fast) no moisture will condense.
Those *are* the laws of physics.
--

Rick

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As usual, it depends on the circumstances. At rest, the head radiates about 7-10% of the body heat. When exercising, the increased surface blood flow increases this to 50%. Presumably, the OP is not exercising under his ceiling fan: <http://skeptics.stackexchange.com/questions/2839/do-we-lose-most-of-our-body-heat-through-our-heads <http://outdoors.stackexchange.com/questions/681/what-are-areas-of-the-body-which-lose-heat-more-quickly-and-how-can-i-reduce-th

Correct, although I suspect the cooling is mostly from evaporative cooling, not convection. The part of my rant that you trimmed indicates that this was in reference to the relative merits of the fan blowing air down or up. I indicated that blowing down would be more effective for cooling because the head is closer to the air source and therefore has a higher air flow rate. Further away would be less effective. If the fan it going to cool the head, the optimum location would be closest to the fan (unless the OP is into standing on his head).
However, the OP didn't specify the temperature of the air near the ceiling. If the ceiling air were hotter than body temperature, a downward blowing fan will heat the cranium instead of cooling it. It would be like trying to stay cool using a hair dryer blowing from above. I can believe that blowing HOT air downward might result in heating instead of cooling.
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Jeff Liebermann snipped-for-privacy@cruzio.com
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On 7/4/2014 11:54 PM, Jeff Liebermann wrote:

Ok, I found this discussion and clicked the link for the first reference on the exercise issue...
Not Found
The requested URL /12401.php was not found on this server. Apache/2.2.3 (Red Hat) Server at researchfrontiers.uark.edu Port 80
The second section refers to a reference that is a Wilderness Medicine Newsletter. I have not heard of them and they do not give references to the work of the people they say they interviewed. So I'm not sure what to believe of the conclusions. They say...
... discovered that we do indeed lose heat through any exposed part of the body and the amount of heat we lose depends on the amount of exposed surface area. The rate of heat loss is relatively the same for any exposed part of the body not simply the head. You do not lose heat significantly faster through the scalp than any other portion of the body with the same surface area.
Later...
As you begin exercise, cerebral blood flow increases due to increased cardiac output and the percentage of heat lost through the head accounts for about 50 percent of total body heat loss. As exercise continues, more oxygen is directed toward muscle and blood flow to this tissue increases. Core temperature has to be maintained and as body heat increases, the skin arterioles expand, or vasodilate, redirecting blood flow to the skin which cools the blood. Hence, total blood flow to the brain is decreased and the percentage of total body heat lost through the head is reduced to about 10 percent. The percent lost through the scalp returns to 7 percent after sweating begins.
So depending on the phase of exercise they claim 50%, 10% and 7% but in contradiction to the initial statements that there is little if any difference in the different parts of the body regarding heat loss.
Earlier in this discussion a post is made the references an old US Army training book, US ARMY SURVIVAL MANUAL, BASIC PRINCIPLES OF COLD WEATHER SURVIVAL. The info in this book has been widely misinterpreted where they talk about wearing a survival suit but with no head protection; then the head does loose 50% of the heat from the body.
Regardless, your claim is about a person nominally at rest I would assume. If you are referring to a person exercising the 50% number only applies during the initial portion of the exercise before they warm up.

This link discusses (again with no verifiable references) that there are parts of the body with higher heat loss per square inch than other areas when not vasoconstricted. But nowhere is there info to support the statement, "The only temperature of importance is your head, which radiates most of the waste heat from your body."
So in the words of Mythbusters... BUSTED!

I objected to this statement...
> "The only temperature of importance is your head, which radiates most of the waste heat from your body."

The point is any reference of cooling the head vs. the rest of the body in invalid. The more important part of the issue is that a ceiling fan blowing up will only cause an indirect, dispersed air flow to the person with nearly no effect.
To talk about the hot air next to the ceiling assumes that that hot air is not dispersed in the first minute of use which is not valid.
The relative cooling has to do with the airflows, not with the thermal emission of the head.
--

Rick

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That's not being nice.
Unless there is

You are turning into Sloman, if you aren't Sloman already. Constant droning insults.
Running the small dehumidifier

See what I mean?
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On Fri, 04 Jul 2014 19:01:04 -0700, DecadentLinuxUserNumeroUno

Can't recall. $40 at Home Depot. Works great.

It moves air nicely, looks good, and it's well balanced and quiet. Nothing sub-par in sight.
There cannot be that great a savings between them, even if

I bought it and installed it. We use it maybe 5 nights a year, when it's hot in San Francisco, which is rarely is.
We passed a big billboard this morning, downtown, right beside highway 101. It must cost a fortune. It's by Nest, the thermostat people. It says, as I recall,
"San Francisco, get a NEST thermostat and save on your summer heating bill."
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On Fri, 04 Jul 2014 19:53:44 -0700, DecadentLinuxUserNumeroUno

I love our ceiling fan. My wife loves our ceiling fan. You don't like our ceiling fan. Fortunately, you don't matter.
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On 7/5/2014 2:10 AM, John Larkin wrote:

Probably a Faux news viewer?
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Christopher A. Young
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On Fri, 04 Jul 2014 23:00:21 -0700, John Larkin

Hey, it's famous already:
http://nancyfriedman.typepad.com/.a/6a00d8341c4f9453ef01a3fd2218a2970b-pi
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On Fri, 04 Jul 2014 19:51:32 -0700, DecadentLinuxUserNumeroUno

Better; move.

Stainless.
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On Sat, 05 Jul 2014 03:45:46 GMT, Ralph Barone

perhaps (running spring water through a cooling coil) but even 50 degree coil will cause condensation in a humid climate.
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system designed for? UP or

I still have three Hunters from circa 1975. They were $200+ then (each); that would be almost $1000 each in today's funny money. None of them have a reverse switch. I guess they figured that people bought fans to blow air on them, not the ceiling :)
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dadiOH
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But the heat produced on the hot coil is mostly ballanced by the cold on the cold coil. The heat on the hot coil is NOT "produced" like it is with resistance heating. It is a "heat pump" and produces a lot more BTUs of heat transfer than the wattage of the power consumption.

What I meant to say is that of the total heat output, only a fraction is produced by the dissipation of electrical energy. The rest is from the Latent heat of condensation.

condensing a gallon in 12 hours - which my little dehumidifier does quite handilly on a Muggly day. My 40 pint dehumidifier dreaws 280 watts maximum. at steady run. So total heat input per hour would be 280+200H0 watts or about 1300 BTU. If it collects the full 5 gallons in 24 hours, it is still less than 800 watts. If you run your AC to remove that humidity I reccon you will need more than a 600 watt heater to make up for it or the AC will be cycling and using a lot more power, and the efficiency in gallons per KW will be a lot lower.

without NEEDING cooling. When it's only 20 C out but 80% humidity, you do not need AC but dehumidification makes a huge difference.
As for your arguments - ask a REAL HVAC professional.
I'm done.
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On 7/5/2014 8:22 AM, snipped-for-privacy@snyder.on.ca wrote:

Those keyboard commandos sure can waste a lot of your time.
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Christopher A. Young
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