Posted by Jeff on May 27, 2008, 4:15 pm
j.soar.aero@verizon.net wrote:
> Then you have that little issue of capacity.
>
>
> " Lets say you have a small 6000 BTU/hr window AC. By definition 6000
> BTUs is 1/2 ton of air conditioning, that is how much cooling you
> would
> get by melting 1000 pounds of ice.
>
> How many pounds of ice will your freezer make in a day? "
>
>
>
> Some simple calcs:
>
> After a hot day my ac runs full time for about 4 hours to cool the
> room in the evening. My ac unit is rated at about 5000 btu/h. At 5000
> btu/h, it would produce 20000 btu of cooling in that time. Melting a
> pound of ice at 32 °F requires 143 BTU. It would take about 140 pounds
> of melting ice (not 1000 pounds)
The 1000 pounds is over 24 hours.
to equal what the ac unit does. That
> would be about 18 gallons of water. One cubic foot of water is 7.5
> gallons. That would be 2.4 cubic feet of water, no capacity problem
> for even a very small freezer.
>
> However that is still a lot of freezing to do in just a few hours of
> sun per day and would take a lot of PV panel area and a very powerful
> freezer to do it (and a lot of money to purchase all of it). So
> probably not practical for around here.
>
> Now I'm thinking of doing something like just running the window ac
> when it can thru a battery-buffered inverter powered by a wind
> generator. There is a lot of wind around here, but of course with
> erratic timing. Plug the ac into the wall/grid when there is no wind.
> Also I could use the power from the wind-gen for electric heat in the
> winter.
There are commercial units that have the inverter built in to the
generator. Those can run either as grid tie or direct connect to your
house. Typically grid tie is more popular.
You'll need to get above the tree line and in addition have some
separation from any trees you have. Of course, you might not have a tree
line!
I have seen one windmill in the city. It was easy for me to find, not
because I could see the windmill, but because I could follow the signs
that all the neighbors had that were opposed to her windmill!
I don't think this will be a cheap endeavor, but neither is PV. Solar
thermal remains the lowest cost which is why I mentioned the salt
desiccant solar thermal AC. It also works best when it is hottest.
Google came up with this:
http://otherpower.com/otherpower_wind.html
If you feel like doing some home brewing. Perhaps you can come up with
an inexpensive tower.
>
> BTW I just got my solar hot water system going, and it looks good so
> far. And I'm now on "real time pricing" for my electric power and it
> is much cheaper from midnight to about 6am, so I'm trying to move some
> loads to that time period, like crock pot cooking, etc. The rates are
> highest in the evening, another good reason to not use the ac in the
> evening.
It seems to me that your primary goal is to reduce cost. Reconsider
your insulation, your attic ventilation and perhaps shading to cut down
solar gain, or a radiant barrier. These are fairly cheap things to do.
By best return here has been insulating the walls in my old home.
If you do the windmill, keep us posted on how it works out. Some of
us may have locations where it is suitable, regretfully I don't.
Good luck!
Jeff
>
> JRB in central Illinois
Posted by Solar Flare on May 28, 2008, 1:24 am
What would you do for A/C in the winter when the lake is frozen?
>-> > Evaporator coil in your water bed mattress?
> -> Or maybe put the ice in the mattress!
> Live near a big lake. Lake Ontario, which is a couple of hundred metres
> from my house, would do just fine. Pump water from deep in the lake,
> where the temperature is constant at 4 deg. C., and pass it through
> your water mattress. Put a good blanket between yourself and the
> mattress or you'll die of hypothermia.
> The same idea is used to air-condition buildings in downtown Toronto.
> dow
Posted by daestrom on May 28, 2008, 11:13 pm
> What would you do for A/C in the winter when the lake is frozen?
LOL, Lake Ontario *doesn't* freeze over all the way. Even so, the ice is on
the top and the lake is more than 800 ft deep, so there's plenty of water
underneath the ice.
daestrom
P.S. While it appears David lives on the northwest shore (near Toronto??),
I live on the southeast shore of the same lake. Just a couple of hundred
miles away :-)
Posted by Solar Flare on May 28, 2008, 11:41 pm
OMG! I hope you don't drink anything after he urinates in it.
Are you the one sending the sleds across the lake with tobacco products in
the winter?
>> What would you do for A/C in the winter when the lake is frozen?
>>
> LOL, Lake Ontario *doesn't* freeze over all the way. Even so, the ice is
> on the top and the lake is more than 800 ft deep, so there's plenty of
> water underneath the ice.
> daestrom
> P.S. While it appears David lives on the northwest shore (near
> Toronto??), I live on the southeast shore of the same lake. Just a couple
> of hundred miles away :-)
>
Posted by daestrom on May 29, 2008, 12:50 am
> OMG! I hope you don't drink anything after he urinates in it.
> Are you the one sending the sleds across the lake with tobacco products in
> the winter?
Again, to reiterate. Lake Ontario doesn't freeze over in the winter. You
can't send something on sleds across that particular lake. Don't know what
you're referring to about 'tobacco products'.
Now, on the other hand, the northern end of Lake Michigan does freeze over.
Deer and other animals migrate from upper Michigan to Beaver Island and
across to Wisconsin (been there, grew up on that lake). Supplies to the
small town on Beaver Island used to be carried by barge/ferry in summer time
and truck in winter time. Spring and fall were the times it was difficult
as the storms and ice floes would keep away ships/barges, but the ice wasn't
solid enough for trucks. The winter trucking was too risky and now small
airplanes are used for vital supplies.
The northern end of Lake Huron freezes over as well. The Coast Guard spends
quite a bit of money on ice-breakers in the winter, trying to keep a
navigable channel open through the Straits of Mackinac (pronounced
"mack'-i-naw").
I read stories that Lake St. Clair (between Huron and Erie) afforded a
crossing for bootleggers to drive cars full of cheap liquor across from
Windsor to Detroit during prohibition. But that was before my time ;-)
Lake Superior doesn't freeze all the way across either even though it is the
northernmost Great Lake. But several bays will freeze over. Until the wind
shifts and pushes the sheets of ice off to another shore.
With Lake Ontario not freezing over in the winter, when cold artic air comes
diagonally down across the lake from Toronto towards the southeast shore, it
picks up a lot of moisture from the 34F water. This results in massive
snowstorms in our area when the moist air comes ashore and rises up the Tug
Hill Plateau (in February 2007, they got 6 feet in one 24 hour storm). All
depends which way the wind blows.
The nice long 'fetch' for prevailing westerly winds means the eastern end of
Lake Ontario and Lake Erie are also prime areas for wind farms.
As far as pollution from Toronto, we don't really worry much about that.
More worried about cities on the US side like Rochester :-) But even so,
you have to understand just how *big* these Great Lakes are. The Clean
Water Act of 74(??) went a long way towards cleaning up the lakes. And a
side effect of zebra mussel invasion has been the lakes are cleaning up
faster than ever.
daestrom
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>
>
> " Lets say you have a small 6000 BTU/hr window AC. By definition 6000
> BTUs is 1/2 ton of air conditioning, that is how much cooling you
> would
> get by melting 1000 pounds of ice.
>
> How many pounds of ice will your freezer make in a day? "
>
>
>
> Some simple calcs:
>
> After a hot day my ac runs full time for about 4 hours to cool the
> room in the evening. My ac unit is rated at about 5000 btu/h. At 5000
> btu/h, it would produce 20000 btu of cooling in that time. Melting a
> pound of ice at 32 °F requires 143 BTU. It would take about 140 pounds
> of melting ice (not 1000 pounds)