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Re: Textbooks filled with lies...

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  Re: Textbooks filled with lies... micky <NONONOmisc07@bigfoot.com> - 2018-04-03 10:20 +0300
    Re: Textbooks filled with lies... Libor 'Poutnik' Stříž <poutnik@privacy.net> - 2018-04-03 10:09 +0200
    Re: Textbooks filled with lies... jimp@specsol.spam.sux.com - 2018-04-03 19:15 +0000
      Re: Textbooks filled with lies... benj <benj@nobody.net> - 2018-04-03 17:24 -0400
        Re: Textbooks filled with lies... Libor 'Poutnik' Stříž <poutnik@privacy.net> - 2018-04-04 08:47 +0200
          Re: Textbooks filled with lies... jimp@specsol.spam.sux.com - 2018-04-04 15:52 +0000
            Re: Textbooks filled with lies... Emory Walpole <aibw@wrtwsgt.lr> - 2018-04-04 16:09 +0000
          Re: Textbooks filled with lies... Sergio <invalid@invalid.com> - 2018-04-04 11:19 -0500

#679724 — Re: Textbooks filled with lies...

Assume a large metal tank of water is placed on top of a house to
provide hot water for the kithen sink and the bathroom sink and tub. 

Assume sundown is at 6.  What color should the tank be?

AIUI, white will not absord the heat as well, but it will keep the head
it does absorb longer, so there will be hot water until 7,8,9 PM

But black will absorb the heat faster, will be able to absorb more heat
on grey days, and will have hot water r eady by noon instead of 2PM.
However it will cool off sooner and the tank will be losing heat evbn
maybe before sundown and very likely the water will be almost cold by 7.


Which of my statements, clauses, adjectives, are incorrect.

What color should the tank be for best hot water. 


Ignore the possibility of sometimes using an electric heater, except
that the solar portion is to be designed to make that as little
necessary as possible.. 

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#679726

Dne 03/04/2018 v 09:20 micky napsal(a):
> Assume a large metal tank of water is placed on top of a house to
> provide hot water for the kithen sink and the bathroom sink and tub. 
> 
> Assume sundown is at 6.  What color should the tank be?

Black.
> 
> AIUI, white will not absord the heat as well, but it will keep the head
> it does absorb longer, so there will be hot water until 7,8,9 PM

It does not absorb heat, it absorbs visible light.
Majority of Sun energy is visible light.
> 
> But black will absorb the heat faster, will be able to absorb more heat
> on grey days, and will have hot water r eady by noon instead of 2PM.
> However it will cool off sooner and the tank will be losing heat evbn
> maybe before sundown and very likely the water will be almost cold by 7.
> 
> 
> Which of my statements, clauses, adjectives, are incorrect.
> 
> What color should the tank be for best hot water. 
> 
> 
> Ignore the possibility of sometimes using an electric heater, except
> that the solar portion is to be designed to make that as little
> necessary as possible.. 

Optimal would be some thermally isolated reservoir
along the path from the collector to warm water tap.

Note that there is huge difference
between properties of surfaces
for visible light and thermal IR radiation.

E.g. for the latter,  snow is near "IR black"
in sense it absorbs near all thermal IR radiation,
and is for this also near ideal black body radiation source.
That is reason,
why during winter season areas with a snow cover
have usually lower morning temperature.
( at comparable weather conditions )

Generally, most of materials are very good thermal IR absorbers.
Exceptions are e.g. metallic thermal foils that reflect most of it.

So it should have black colour,
as majority of energy of Sun radiation
is in the visible range.

For radiation of the heat during the night,
it almost does not matter, as black and white colours
are comparably "black" for thermal radiation.

It cannot be the foil, as it would reflect the light.



-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.

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#679782

micky <NONONOmisc07@bigfoot.com> wrote:
> Assume a large metal tank of water is placed on top of a house to
> provide hot water for the kithen sink and the bathroom sink and tub. 
> 
> Assume sundown is at 6.  What color should the tank be?
> 
> AIUI, white will not absord the heat as well, but it will keep the head
> it does absorb longer, so there will be hot water until 7,8,9 PM
> 
> But black will absorb the heat faster, will be able to absorb more heat
> on grey days, and will have hot water r eady by noon instead of 2PM.
> However it will cool off sooner and the tank will be losing heat evbn
> maybe before sundown and very likely the water will be almost cold by 7.
> 
> 
> Which of my statements, clauses, adjectives, are incorrect.
> 
> What color should the tank be for best hot water. 

No one with the slightest bit of sense would attempt to use a tank
to collect solar heat.

-- 
Jim Pennino

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#679808

On 4/3/2018 3:15 PM, jimp@specsol.spam.sux.com wrote:
> micky <NONONOmisc07@bigfoot.com> wrote:
>> Assume a large metal tank of water is placed on top of a house to
>> provide hot water for the kithen sink and the bathroom sink and tub.
>>
>> Assume sundown is at 6.  What color should the tank be?
>>
>> AIUI, white will not absord the heat as well, but it will keep the head
>> it does absorb longer, so there will be hot water until 7,8,9 PM
>>
>> But black will absorb the heat faster, will be able to absorb more heat
>> on grey days, and will have hot water r eady by noon instead of 2PM.
>> However it will cool off sooner and the tank will be losing heat evbn
>> maybe before sundown and very likely the water will be almost cold by 7.
>>
>>
>> Which of my statements, clauses, adjectives, are incorrect.
>>
>> What color should the tank be for best hot water.
> 
> No one with the slightest bit of sense would attempt to use a tank
> to collect solar heat.
> 
Greens are "idea men", Jim. They solve all the big problems to save the 
world and then leave it to guys like you to work out the details of 
their ideas and make them work.

I have an electric hot water tank run from a coal-fired power plant. It 
gives me great hot water no matter what the weather outside! What is the 
best color for my tank?

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#679881

Dne 03/04/2018 v 23:24 benj napsal(a):
> On 4/3/2018 3:15 PM, jimp@specsol.spam.sux.com wrote:
water.
>>
>> No one with the slightest bit of sense would attempt to use a tank
>> to collect solar heat.

Sure, flat collectors are better.
Only advantage for the directly heated tank
is a low badget.

> I have an electric hot water tank run from a coal-fired power plant. It
> gives me great hot water no matter what the weather outside! What is the
> best color for my tank?

What is the best tank colour
if there is no electricity grid ?

It happens even in such countries as US or Canada
if one has got an outdoor hut or a log cabin.

Additionally, direct thermal conversion
has better efficiency that heating the water tank
by electricity from solar panels.

And even if there is grid electricity,
why to pay for it if you need not to ?


-- 
Poutnik ( The Pilgrim, Der Wanderer )

A wise man guards words he says,
as they say about him more,
than he says about the subject.

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#679907

Libor 'Poutnik' Stříž <poutnik@privacy.net> wrote:
> Dne 03/04/2018 v 23:24 benj napsal(a):
>> On 4/3/2018 3:15 PM, jimp@specsol.spam.sux.com wrote:
> water.
>>>
>>> No one with the slightest bit of sense would attempt to use a tank
>>> to collect solar heat.
> 
> Sure, flat collectors are better.
> Only advantage for the directly heated tank
> is a low badget.

Since such will not "work", there is no advantage.

>> I have an electric hot water tank run from a coal-fired power plant. It
>> gives me great hot water no matter what the weather outside! What is the
>> best color for my tank?
> 
> What is the best tank colour
> if there is no electricity grid ?

There is no electrical connection to my hot water tank.

<snip remaining>


-- 
Jim Pennino

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#679908

jimp wrote:

>> What is the best tank colour if there is no electricity grid ?
> 
> There is no electrical connection to my hot water tank.

You may try turning on yur shithouse into a bio-gas driving current 
generator, so you can heat your water as you like.

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#679911

On 4/4/2018 1:47 AM, Libor 'Poutnik' Stříž wrote:
> Dne 03/04/2018 v 23:24 benj napsal(a):
>> On 4/3/2018 3:15 PM, jimp@specsol.spam.sux.com wrote:
> water.
>>>
>>> No one with the slightest bit of sense would attempt to use a tank
>>> to collect solar heat.
> 
> Sure, flat collectors are better.
> Only advantage for the directly heated tank
> is a low badget.
> 
>> I have an electric hot water tank run from a coal-fired power plant. It
>> gives me great hot water no matter what the weather outside! What is the
>> best color for my tank?
> 
> What is the best tank colour
> if there is no electricity grid ?
> 
> It happens even in such countries as US or Canada
> if one has got an outdoor hut or a log cabin.
> 
> Additionally, direct thermal conversion
> has better efficiency that heating the water tank
> by electricity from solar panels.
> 
> And even if there is grid electricity,
> why to pay for it if you need not to ?
> 
> 

google around, this technology is well developed

https://metaefficient.com/hot-water-systems/90-of-israel-homes-have-solar-water-heaters.html

https://www.greenprophet.com/wp-content/uploads/2010/07/solar-water-heaters-on-roof_lbiRv_5784111-500x282.jpg

https://upload.wikimedia.org/wikipedia/commons/thumb/d/db/Calefon_solar_termosifonico_compacto.jpg/1200px-Calefon_solar_termosifonico_compacto.jpg

http://image.made-in-china.com/2f0j10fKtakpdlOQcq/-Calentador-de-agua-solar-residencial-de-la-.jpg

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