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Grex > Agora41 > #52: Summertime energy efficent homes. | |
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| 25 new of 103 responses total. |
keesan
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response 75 of 103:
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Apr 15 02:40 UTC 2002 |
No, in the daytime when the sun in shining. At night, at least in Michigan,
it is already cool enough out that the house will not warm up over 75 if you
have any insulation. If you add some thermal mass that would also help.
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slynne
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response 76 of 103:
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Apr 15 13:34 UTC 2002 |
I wish someone would make a solar powered lawn mower.
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keesan
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response 77 of 103:
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Apr 15 13:50 UTC 2002 |
There are battery operated mowers - you would just need to hook the recharger
up to solar power. No need to combine the two in one heavier unit. The sun
does not provide enough power to run the mower without a battery, unlike less
power intensive things like those little caps with solar fans on them. There
are solar powered yard lights that run on batteries - I don't know how they
recharge. People with mowers might not want to leave them outside to charge
if the charger were built in.
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slynne
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response 78 of 103:
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Apr 15 14:41 UTC 2002 |
I have the solar powered lights. They have a battery that charges
during the day.
I should look into a battery powered mower because that would be cool.
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eprom
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response 79 of 103:
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Apr 15 19:25 UTC 2002 |
re#5
Interesting...I think I will tint the south-facing windows.
I was looking around at Home Depot a few days ago and it seems
that the tinting comes in two colors: gray or brown.
Which color would be better at blocking radiated heat?
I'm thinking the gray color has a shorterwave length and would
block longer wavelength (i.e infared) more effectively.
I also cleaned all the dust and stuff off the AC's squirrel cage
motor and vaccuumed all the coils...hopefully that helps too.
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gull
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response 80 of 103:
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Apr 15 20:10 UTC 2002 |
Re #75: Huh? I'm sure I remember summer nights when it didn't get below
85. Lots of them. Fans also don't do anything to remove the humidity
from the air, which is a lot of what makes it 'feel' hot.
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keesan
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response 81 of 103:
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Apr 15 21:13 UTC 2002 |
Fans help you to feel cooler even when it is humid, by evaporating the water
from your skin, which is 100% humid. All the summer nights that I can
remember dropped to 75 by 6 am - of course there were times when it was still
83 or so at midnight, which I find tolerable for sleeping even with no fan.
Don't know about which window film to try. We tried it and decided it was
not worth the bother. It darkened the room in the winter. Window shades made
of mylar would work better.
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mvpel
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response 82 of 103:
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Apr 15 21:43 UTC 2002 |
Re: 76 - they already make a solar lawn mower.
http://www.greenculture.com/pr/mowers.html - scroll down and you'll see it.
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other
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response 83 of 103:
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Apr 15 23:23 UTC 2002 |
Brown is red and green, so what it is blocking is blue, the shorter
wavelengths. That means that the infrared range will still penetrate,
and that adds heat, but it also means your upholstery will not fade
because that is caused by the ultraviolet wavelengths.
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russ
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response 84 of 103:
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Apr 16 00:54 UTC 2002 |
Re #73: The real issue is how long it will be used before it is removed or
replaced. Central air units and heat pumps typically last 20 years or so.
An in-ground tank with some insulation would probably hold together for at
least that long, maybe much longer. If it takes less energy to make than
the solar-powered heat pump, you've got a net win. You could also use the
system to decrease energy used by other things, such as the refrigerator.
"Moving the cold around" costs almost nothing. Water is an amazingly
efficient way to move heat; pumping water requires far less energy than
moving air, as little as a few watts. One solar panel will run the pump;
it would take a roof-full to run an A/C compressor. I don't have anything
against solar-powered chillers (I think they're a pretty neat idea), but
if you can save a buck (or thousands) by letting Nature do the chilling
for you, does it make sense to do things the hard way? Especially if you
can dispose of your winter snow-piles at the same time?
The volume of the ice-pit would be about as much as a back-yard swimming
pool (assuming it was full of ice and not slush); compared to the volume of
a typical basement, that's not huge. The increase in energy required to
build the house would be moderate, and you could put part of the ice-pit
above ground by incorporating it into another feature, like a patio or deck.
That would further decrease the amount of earth moved and energy required.
If I'm not mistaken, the amount of fuel consumed to run a typical house
out-weighs the house long before the mortgage is paid off. Snow storage
is one way to change that from the supply side (which is comparatively
untapped and has low hanging fruit) as opposed to the demand side.
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gull
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response 85 of 103:
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Apr 16 13:39 UTC 2002 |
I'm not sure this is really practical for homes. Most cities aren't
going to let you put a big pit in the front yard, and it's a lot of work
to haul all the snow from the driveway around to the back yard. It
might make sense for businesses, which are generally trucking their snow
elsewhere anyway, but they're often cramped for space and giving up a
big chunk of parking lot to make a pit may not be attractive.
I also wonder if you'd have trouble disposing of the melt water. It'd
probably have a high salt concentration, and pick up a fair amount of
oil from the parking lot, so you may not be allowed to put it in the
storm sewer. You would definately not be allowed to put it into the
sanitary sewer, though, because it's precipitation.
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slynne
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response 86 of 103:
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Apr 16 14:03 UTC 2002 |
re #82 Oh man, I feel that I must have one of those things! Thanks for
posting the link.
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senna
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response 87 of 103:
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Apr 16 17:49 UTC 2002 |
The one quality I admire about Russ is his ability to think of and promote
practical ideas for inventive concepts like this. They might not always be
workable, but he's certainly willing to think outside the box and it's a trait
that needs to be encouraged a lot more.
I think if houses or retail space was developed with snow storage in mind,
it could be very workable. You could installe a parking area *over* such a
pit, for example.
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mvpel
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response 88 of 103:
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Apr 17 00:18 UTC 2002 |
Exactly - a grate instead of asphalt paving, for example, where you'd just
plow all the snow into it.
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senna
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response 89 of 103:
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Apr 17 00:54 UTC 2002 |
It feels weird agreeing with both russ and mvpel on somehing. Oh well, it
had to happen. :)
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russ
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response 90 of 103:
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Apr 17 04:13 UTC 2002 |
Re #85: I can think of several places to put the storage, which
might even be highly convenient:
1.) Under a deck or patio (already mentioned).
2.) Under the floor of the garage (which is usually wasted).
3.) Under another broad paved area, such as a driveway, commercial
sidewalk or parking lot.
4.) Beneath the foundation slab of a basement-less building.
I think the most interesting spots are #3 and #4. In a snowy winter,
snow plowed from parking lots is often piled up in huge dunes which
sometimes don't melt completely until late May or even later. Snow
falling on flat roofs has to be removed (usually melted off) or the
roof will collapse. If you could turn this snow into a runny slush
and sluice it into an insulated tank below grade, it just *disappears*.
You could use a sprinkler system to make ice during winters without
much snow (or even on frosty nights) just to fill the tank. Done on a
roof it would warm it up to freezing, reducing heat loss. The Rocky
Mountain Institute flushes their roof with groundwater to keep snow
from building up, so this isn't breaking new ground.
I don't think salt and oil would be much of a problem. Anything that
normally goes down the storm sewer should be legal, and you could skim
it just to be fastidious. The real difficulties are probably going to
be grit and clogging.
You know, a building which used this technique might not need any
electricity for A/C during the summer. If it used skylights and such
carefully, it might avoid a lot of lighting as well. You might be able
to get rid of a large fraction of the operating expenses and get really
cheap off-peak electric rates too. That adds to the bottom line.
Re #87: I'm borrowing a lot of this from older concepts, such as the
Annual Cycle Energy System (described who-knows-where in a magazine
who-knows-how-long ago), the Rocky Mountain Institute, and elsewhere.
Other people think it up; I just vet it for reality and synthesize.
"If I have seen further, it is because I have stood on the shoulders
of giants."
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jaklumen
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response 91 of 103:
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Apr 17 05:14 UTC 2002 |
I'd love to visit the Rocky Mountain Institute. From what I've read,
it sounds like quite a place.
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keesan
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response 92 of 103:
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Apr 17 12:14 UTC 2002 |
It would need to be a pretty strong roof on your storage structure to serve
as a parking lot. Skylights let in direct sun and therefore a lot of heat.
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jmsaul
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response 93 of 103:
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Apr 17 14:39 UTC 2002 |
Re #90: I'm intrigued. Is this all theory, or has someone been using it?
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dbunker
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response 94 of 103:
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Apr 18 02:51 UTC 2002 |
Re #92: Rooftop parking is fairly common in certain parts of California.
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russ
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response 95 of 103:
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Apr 18 04:17 UTC 2002 |
Re #92: Sunlight is about 50% infrared, and can be filtered to reduce
that quantity. Skylights can be shaded when necessary. In contrast,
a fluorescent lamp is only about 27% efficient or so. A watt of light
from sunlight yields about 2 watts of heat at most, while a watt of
light from fluorescents yields at least 3.7 watts of heat - plus you
have to pay for the electricity.
Parking structure floors are at least as strong as a tank roof located
beneath parking would have to be; parking structures must bridge longer
spans because vehicles must fit between the support columns. If you
didn't take the easy way out and locate the storage beneath a sidewalk
(blocked off to vehicles), it still wouldn't be hard to manage; you could
use pre-cast concrete slabs on top, resting on insulated columns rising
from piers below the tank. As long as they don't conduct too much heat
in, it doesn't matter how closely the columns are spaced.
Re #93: There have been pilot tests of lots of different concepts, and
they apparently work but didn't get any traction in the market. The
ice-storage scheme with snow guns has been written up more than once but
I could not point you to a reference. The "Annual Cycle Energy System"
used a heat pump to draw heat from an insulated pool of water, yielding
heat in the winter and saving the ice for free cooling in the summer;
you may be able to find something on this via your favorite search engine.
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mvpel
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response 96 of 103:
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Apr 19 01:24 UTC 2002 |
What about lumens of light, Russ?
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mdw
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response 97 of 103:
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Apr 21 01:46 UTC 2002 |
At least while they use salt on roads, I think anything that's made of
concrete and has cars parking on it in winter has to be regarded as
"disposable". It seems the salt reacts with the concrete to make it
crumble. It also seems to have a bad effect on iron reinforcing rods.
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gull
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response 98 of 103:
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Apr 21 02:23 UTC 2002 |
You could use something other than salt to melt the ice on the parking
lot. Some will still get tracked in by cars, but the damage will be
reduced.
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russ
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response 99 of 103:
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Apr 21 23:55 UTC 2002 |
Salt destroys concrete (actually, the portland cement which bonds
it together) by displacing calcium ions with sodium ions.
This isn't necessarily a big deal. If the cover plates are precast
slabs in standard sizes, they can just be replaced when they start
to fail. They can also be sealed with something like asphalt.
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