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[compost_tea] Re: Heating & Maintaining CT water and other subjects.



Just wanted to chime in for a second on solar heating and thermal 
transfer because of a statement below about heating water.  

The process of heating water with pipes collecting solar energy 
requires that heat energy developed at the surface of a pipe due to 
solar radiation be transfered to the water on the other side of the 
pipe.  Heat travels fastest when there is a strong gradient so the 
pipe should conduct heat to the water most efficiently when the water 
is coldest and the pipe hottest.  
This would indicate that the first degrees of temperature rise in 
solar heaters should be faster than the last, when water and solar 
collector are near the same temperature.  
Each degree of temperature rise requires the same number of BTU's of 
energy be it the rise from 10-11 degrees or 80-81 degrees, it is only 
the speed of transfer of energy that changes as the temperatures 
between the pipe and the water are closer or further apart in 
temperature.

That's the way I learned it anyway.

Dave



--- In compost_tea@yahoogroups.com, Robert Norsen <bnbrew@y...> wrote:
> George and Paulette - By far the best solar heating is what you 
descibe.  Merla and Herb may need a storage system to be able to heat 
the water and hold it for use when needed.  A well with a low volume 
could be heated as it comes from the well with that solar heating 
panel during full sun.  Thanks Paulette,  Bob.  
> 
> George and Paulette Mouchet <geomouchet@Q...> wrote:For about $250 
you can buy an above ground solar pool heating mat.  The mat 
> is flexible, about 5 feet wide and comes in different lengths.  It 
is made 
> of many, many rows of black tubing.  The water flows through, 
heating up as 
> it goes.  A 20-foot long mat will heat about 5,000 gallons.
> 
> Here's a link:
> http://www.solar-tec.com/PoolHeatingAboveGroundPools.htm
> 
> Paulette
> 
> 
> 
> 
> 
> 
> -----Original Message-----
> From:      Mike Harvey [SMTP:mharvey@w...]
> Sent:      Tuesday, April 29, 2003 6:20 PM
> To:      compost_tea@yahoogroups.com
> Subject:      Re: [compost_tea] Heating & Maintaining CT water and 
other 
> subjects.
> 
> I have been using a solar system to heat up about 600 gal
(3000Litres) of 
> water for CT tank for the last 8 months. It is relatively simple, 
cheap 
> and very effective if the sun is shining.
> I use about 400metres of 3 quarter poly pipe with irrigation 
fittings. This 
> is placed on the roof of a shed. the water is pumped around and 
raises the 
> temp fairly fast say 4 hours from 13 deg C to 30 deg C (inoculation 
temp).
> 
> Obviously you would not need a system as big as this for smaller 
amounts 
> however the same principles apply. Storage of the heated water 
prior to use 
> can be useful also.
> Also consider that the most energy for heating water is moving it 
from 
> those first degrees not the last degrees.
> You should not run the CT through the pipes though as films will 
build.
> Regards Mike Harvey
> www.composttea.com.au
>   ----- Original Message -----
>   From: Robert Norsen
>   To: compost_tea@yahoogroups.com
>   Sent: Wednesday, April 30, 2003 1:35 AM
>   Subject: Re: [compost_tea] Heating & Maintaining CT water and 
other 
> subjects.
> 
> 
>   Merla when you take our electric power line out of our lives and 
CT 
> production you screw up everything.  We flatlanders don't know how 
to cope. 
> I was thinking park it in the sun and it will warm up just as I 
began to 
> read that suggestion from you.  Solar heating may be your best 
source.  Any 
> chance you could have a green house with water storage in it to 
warm  water 
> for all your use?  Bath, laundry, and CTEA?
> 
>   It says in the solar heating science data that High temp. solar 
heat 
> enters thru glass but that low temp heat source ( the heated water) 
does 
> not exit thru glass.  So over several days the average heat in the 
water 
> would increase to where it would be useful for all those purposes.
>   Paint the water tanks in the greenhouse black and cover to pevent 
> evaporation cooling. Pump cold water in at bottom, take warm water 
from the 
> tip. Do that 3 or 5  or more 50 gallon barrels in series. Each cold 
in at 
> bottom warm out at top into the next barrel at the bottom etc.  
Your well 
> water pump drives the flow.  End barrel is rather hot water.  The 
more 
> barrels the larger the capacity to heat  It is called passive solar 
> heating. It works.
> 
>   If I know anything about you and Herb I know you have already 
> investigated this.  Such a solar system is not a small or simple 
project.
> 
>   Subject #2  WEEDS
> 
>   I've been working in my yard some of late.  We have some daiseys 
and a 
> few other wild flowers that grow like weeds only better. They seed 
and 
> reseed and come up from the roots after a long winter and act just 
like 
> weeds except they don't spread on the wind or creep underground and 
they 
> are rather good looking as bright flowers most of the year. They 
are the 
> first to bloom in spring and keep blooming all summer.  Clover 
would be 
> another great flower to plant.  Since these plants are all affected 
by 24D 
> you could rightfully object to the area being sprayed . Patrolling 
for 
> other noxious weeds on an 8 mile road will still be a BIG project. 
But if I 
> were a betting man ( I am) I would bet on the daiseys,
> 
>   Subject #3  PIONEERS
> 
>    When you feel sorry for yourselves there without the powerline 
remember 
> how the rugged pioneers survived without .  And how luckey you are 
that you 
> live in such a beautiful environment.  And how luckey we all are to 
have 
> people like you defending that beautiful environment. Thanks Merla 
and 
> Herb!  Bob
> 
>   Subject #4 I think I am appearing too dam often on this show.
>   Merla Barberie <herbnmerla@s...> wrote: << File: ATT00038.htm >> 
> 
> 
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