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re: passive solar is affordable
23 aug 1996
carlos portela wrote:
>nick pine wrote:
>> conrad wrote:
>> >passive solar has a big drawback due to the laws of physics. since you
>> >are living within your heat storage medium you must put up with
>> >temperature variations.
>> false.
>nick is correct. passive solar does not increase temperature swings.
thanks carlos, but what i've been trying to say is that if a passive solar
heat store is always warmer than the house, by design, it can keep the house
at a constant temperature by supplying the house with more or less heat as
required, making the house temperature swing z e r o ...
>in fact, the opposite is true. passive solar reduces temperature variations,
or in some cases, completely eliminates them. "passive solar" covers a lot
of territory, even slightly active systems, to me. those with a cop of 10,000,
for instance, eg a system that controls 20 kw of solar heat with a couple of
thermostats and a 2 watt motorized damper, one that might be pv-powered. let's
not be passive purists.
>for example, consider a common passive solar strategy:
>installing red brick veneer on part of an interior wall
>that receives direct sunlight in winter...
now in that case, there will be temperature swings, and we do have to live
inside the heat store. how can this be improved? use the same volume of water,
vs bricks, because water stores 3 times more heat than bricks by volume, and
put it in an insulated box, so it can heat up to 130 f, vs 80 f, and heat
water for showers, and supply *15* times more heat than those bricks, with a
temperature swing of 50 f vs 10 f, while keeping the house at exactly 70 f
during a cloudy week. the box might also contain a sauna or a hot tub or a
clothesline.
>winter sun will help warm that wall, causing the
>house to be more evenly heated than from point sources
>of heat from non-renewable energy sources.
>not just that, but the heat is released all night
>at a much slower and even rate than the non-renewable
>forced air. the forced air will have to switch on
>less often, since the temperature range that kicks on
>the forced air thermostat takes longer to reach extremes.
some people define a "solar house" as one with no other form of heat.
it's easy to make one of these 100% solar heated houses. just turn off
the backup system. or don't put one in :-) design the house so it doesn't
need one. would you hang an outboard motor on an america's cup boat?
how would you like to live in a zero-fossil-fuel house, with walls less
than a foot thick, and not burn wood, nor use electricity for heating?
>these types of simple affordable passive solar design
>strategies increase the comfort levels of any standard house.
yes, but let's build more beautiful solar sailboats. performance machines :-)
nick
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