OT Which direction is your ceiling fan SUPPOSED to run?

On Saturday, July 5, 2014 8:22:28 AM UTC-4, snipped-for-privacy@snyder.on.ca wrote:

I agree. A dehumidifier is not "exactly like" running a central AC and the heat at the same time. As you say, a dehumidifier is a heat pump and it's transfering heat from the cold side to the hot side. Since both the cold and hot side are in the same room, that part of the energy is constant. Since the heat pump does take energy to run, the electricity used does result in some heat being added to the room. But because the COP of a dehumidifier is much greater than one, you're moving 2x or 4X the energy that dehumidifier takes to run. Running the AC is essentially a heat pump too. Except there you're pumping the heat from inside outside, where it's lost. And then you're running the heat, ie gas heat, electric resistance heat, whatever, to make up for all the lost heat. That's a huge difference in efficiency and a very inefficient and costly way to dehumidify compared to running a dehumidifier.
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On 7/5/2014 12:19 PM, trader_4 wrote:

333 lines of text --- got to be a record. Do you know how to trim, or do we have to teach you?
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Christopher A. Young
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On 7/5/2014 8:22 AM, snipped-for-privacy@snyder.on.ca wrote:

There is your fallacy. The heat produced at the hot coil is largely balanced by the cold at the cold coil (with the exception of the power drawn from the outlet which is not trivial) but the cold coil does not cool the air as much as the hot coil heats the are. Most of the heat entering the cold coil is used to condense the water which does *not* cool the air. The opposite of evaporative cooling is condensative heating. Heat has to be extracted from the moisture to condense it which does not cool the air while that same heat at the hot coil *does* warm the air.

Ok, but not a useful point.

I'm having trouble following your statements because I can't tell what "drawing" and "heat input" refer to. Are you saying the unit draws 280 Watts from the power line? I don't really see where you are going with this and I certainly don't see how you can compare the two types of units in this vague way.

Ok, but until you understand the real heat flow, you can't say you understand what is happening with your dehumidifier. If it is 20°C outside and you run your dehumidifier you will be heating the air which may not be insignificant. So if you want your home to be 22°C with 50% humidity then a dehumidifier may be the right choice.
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Rick

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On Saturday, July 5, 2014 2:39:02 PM UTC-4, rickman wrote:

That's true, but it has nothing to do with your claim that turning on the central AC and the heat at the same time is "exactly the same" as running a dehumidifier. They are very different.
The opposite of evaporative cooling is condensative

Which again, has nothing to do with the claim. If you run an AC, you're taking heat from *inside* the house and pumping it *outside*. Your suggest ion to turn on the heat to make the AC run more without lowering the temp, means that now you're burning gas or using electric resistance heat, etc, to make up for that lost heat that just went outside. It is not at all like using a dehumidifier. If you want to lower the humidity while not lowering the temperature, it's far more efficient to do that by running a dehumidifier than it is to do it by running the AC and heat at the same time.

e
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It is the whole point, CL is right.
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?C

th 50%

The guy is running a humidifier in his bathroom. That isn't going to raise the temp of the house by 2C. A dehumidifier is about 500W. Can you raise the temp of a whole house by 2C with just 500W? And even if it did, you'd be far better off running the dehumidifier to reduce the humidity and running the AC to reduce the temperature by the 2C, than you would be running the AC and the heat at the same time.
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On 7/5/2014 2:39 PM, rickman wrote:

252 lines of text -- please trim.
A dehumidifier contains a motor of some number of watts. So it puts electric heat into the room.
If the dehum is broken and runs all the time without removing humidity, it can really increase your electric bill.
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Christopher A. Young
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:)
I used to get to SF 2-4 times a year, usually between October to May. I tried to avoid July, BITTER cold!
My first experience with SF "summer" was in July, 1952. I was in the navy, waiting to be shipped to Hawaii. There used to be a jazz club on Geary just off Powell called - IIRC - Club Hangover. To this day, I remember turning the corner off Powell and being met with a blast of arctic air. DAMP arctic air.
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On Sat, 05 Jul 2014 06:52:17 -0400, Stormin Mormon

Give it a rest already. Rour totally unballanced psyc is showing!!
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On 7/5/2014 8:31 AM, snipped-for-privacy@snyder.on.ca wrote:

>

> unballanced psyc is showing!!

Part of the def'n of Totalitarian is trying to suppress opposing views.
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Christopher A. Young
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On 7/5/2014 8:40 AM, Stormin Mormon wrote:

What about suppressing idiotic views? Is that totalitarian or just hard to resist?
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Rick

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On 7/5/2014 2:45 PM, rickman wrote:

> that totalitarian or just hard

Culturally insensetive. Like kicking puppies.
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Christopher A. Young
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On 7/5/2014 6:25 PM, Stormin Mormon wrote:

In what culture is kicking puppies acceptable?
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Rick

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On 7/5/2014 7:26 PM, rickman wrote:

Usenet?
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Christopher A. Young
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wrote:

I didn't paint the roof, it's tile and its color is its color.
I painted the walls which receive oblique sunlight and sometimes no sunlight with the eaves shading. I only experienced 'cooler' HOT temperatures in the garage and the fact our inside home stayed a 'tighter', and lower, average when we weren't running A/C etc.
I would expect that during the day a white roof would be cooler. Having a superheated black structure above your head just can't be as cool. No aspersions on life style meant.
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Right. My problem is that my house is environmentally incorrect and far from typical. There's no attic. The roof and ceiling are non-insulated 2x T&G pine[1]. There's considerable (double pane) glass in the walls. Add two single pane sliding glass doors and two single pane French doors. Air leaks around some doors and windows. With so many leaks, my rule of thumb is that the house temperature never goes above or below about 20F from the outside temperature, even when running the woodburner. Such a house would not be practical in any extreme environment, but reasonably functional in a dense redwood forest, where the trees moderate the temerature swings. As you note, the door/window temp regulation method is functional for most houses. However, my efficiency, as indicated by the equal temperature time, is far from optimum.
10 year old photo: <
http://802.11junk.com/jeffl/pics/home/BL-house3.jpg

[1] The roofing is 20 years old and probably has another 5-10 years of useful life reamining. I plan to insulate the roof when it is replaced.
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Jeff Liebermann snipped-for-privacy@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
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Thanks for the real world example. That's what I would have expected from mixing up the warm and cool air. Once the air is mixed up, there's no further change in the temperature from the ceiling fan.
Of course, if you have a loft or something up near the ceiling, dropping from 33C to 24C would be very welcome. :)
Anthony Watson www.mountainsoftware.com www.watsondiy.com
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On Sat, 05 Jul 2014 06:58:52 -0700, RobertMacy

A few web pages recommend painting your tile roof white: <http://www.doityourself.com/stry/thermal-benefits-of-painting-a-tile-roof-white Of course they're selling the paint, which does tend to bias the point of view. I'm not sure it will make a difference or an improvement.
<http://en.wikipedia.org/wiki/Reflective_surfaces_(geoengineering)> There are charts available showing the SRI (solar reflectance index) but I don't want to dig through them to determine if coating your tile roof will offer any benefits.
<http://heatisland.lbl.gov/sites/heatisland.lbl.gov/files/Cool-roof-Q+A.pdf A roof with a clean, smooth "cool color" surface, such as a cool red tile, can reflect about 35% of incident sunlight (R = 0.35) and emit thermal radiation with 90% efficiency (E = 0.90). This surface has an SRI of 38 and a delta T of 56°F [31 K]. The cool red tile is much warmer than the bright white roof, but still cooler than a standard red tile (R = 0.10, E = 0.90, SRI = 6, delta T = 78°F [44 K]).

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Jeff Liebermann snipped-for-privacy@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
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On 7/5/2014 12:20 PM, Jeff Liebermann wrote:

What exactly is "cool red tile"? What is different in it's construction from hot red tile?
I looked at the reference and I'm not sure I understand what they are measuring. I learned many years ago that a surface can not have different abilities to absorb or emit heat. If it did it would spontaneously warm up or cool down. But I suppose it can be a matter of different rates of emission/absorption at different wavelengths. Solar is IR, visible and UV. Once warm, the heat from a surface would be IR, possibly long wave IR. So I suppose you can achieve an advantage by having a low coefficient at the shorter wavelengths and a higher coefficient at long wavelengths resulting in higher emissivity at night and a lower absorption during the day.
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Rick

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wrote:

That's nice, in the woods.
When we refurbed our business building, and redid the flat roof, we added a roughly 4" thick thermal insulator, and painted that aluminum. The ceiling in my office stays just about the seme temp as the floor.
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...

....

...

You ARE Sloman!
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On Sat, 05 Jul 2014 10:05:40 -0700, John Larkin
Thanks. I wanted to buy a house "away from it all" in about 1974. At the time, only about half of the houses in the neighborhood were occupied year round. The rest were vacation houses, Section 8 housing, and methamphetamine factories. It was common for the dogs to sleep in the roadway. That worked well until the 1990's, when living in the trees was deemed fashionable that everything I was trying to get away from moved in next door. That's not really bad news as the local infrastructure has gradually improved over the years, and rising home prices has introduced a better class of residents. Be careful. This type of progress can also happen to you.

Hmmm... that's about what I would expect from a concrete slab floor. The thermal sink it provides is substantial. If it has cold water pipes running through it, even better. You might try the same test with the HVAC and circulation fans turned off. I did that once (when I was complaining about the air conditioning not working) in my palatial office (thin carpet on slab with a 3ft suspended ceiling with minimal insulation). I vaguely recall almost no differences with the fans going, but about 15 or 20F difference after about 2 hrs in still air. This is measuring air temp with a thermocouple probe, not an IR thermometer. However, we had a new roof installed late last year and I should probably retest this again. The new reflective roof is noticeably better than the old asphalt black roof.
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Jeff Liebermann snipped-for-privacy@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
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