Hot water at summer camp [RE-wrenches]

Sat Mar 24 05:43:21 PDT 2007

<x-flowed>

Chemistry was never my strong point-- an understatement-- but I believe " 
acid rain " has more to do with some of the other pollutants coming from 
coal burning, rather than CO2. Sulfer dioxide, I think, as in sulfuric acid. 
Our shallow aquafir and surface watewr also tends to the lower ph due to 
pine and oak trees. Pine needles especially keep the surrounding soil a 
lower ph.. Any chem majors or soil scientists care to chime in?

Drain Back systems-- not to be confused with Drain Down systems !-- are not 
only better when overheating and stagnation is likely. They are also more 
efficient due to the following issues;
1--water is a better conductor than antifreeze solutions
2--if you use a large,unpressurized tank, with the heat exchange to 
pressurized water on the output side, the the water circulating thru the 
collector will be cooler.
    The efficiency curve of a flat plate collector is sensitive to inlet 
water temp. So if we want to maximize our BTU input, we need to work with 
the     coolest fluid temps practical .

Some other advantages;

1-- with an unpressurized tank, it is easy to put heat in from other 
sources, say a wood boiler.
2-- it is also easy to take heat out, say for radiant slabs, or fan 
convectors.

Now for the Summer camp--

I never got answers needed to now the details of appropriate design-- and ' 
the devil is in the details' so I'll make some assumptions;

1-- summer camp means june, july and august
2- location is Texas, daytime temps in the 90's or hotter
3- incoming water temp is 70-80 F, unless the source includes a large 
aboveground storage tank, which might well be hotter.
4-shower temps will be 95-120F  [ sweaty kids may well like a cool shower at 
4PM after a day in the Texas sun !]
5- 14 showers at 2gpm x 5min equals 140 gals in less than an hour, per cabin
6- there are 21 systems ----lets assume 20 cabins and one kitchen, which has 
a different load profile and higher hot water temp needed.Up to 180F.
7- at least some of these structures are grouped , say less than 50 ft 
apart.

For the kitchen, I would then think about an appropriate size glazed 
collector-- I've always been happy with the AET collectors --and an 
unpressurized site built tank with submerged SS tanks as the output heat 
exchange. If the tank is at least 2 gal/ sq ft of collector, efficiency 
should be quite high and water temps low enough to limit scaling. If the 
water supply is chlorinated then 316, rather than 304, SS should be used . 
If a commercial water heater is used for 180F sanitizing dish washing is 
used, then they may have, or want to install a softening system designed for 
their needs.

For the cabins, I'd consider using unglazed pool collectors, roof mounted on 
the sunniest cabins with appropriate size drainback heat exchange tank, 
exterior location, to twin 80 gal electric tanks in the shower area.If there 
were an unusual cool cloudy spell predicted, the elements could be activated 
at off peak times. The larger the drainback tank, the better the carry thru 
for those unusual days. Underground , insulated, piping in sealed plastic 
drain pipe [ sealed to prevent condensation building up in the drain pipe] 
would connect the cabins to the main storage/ heat exchange tank.

If some of my assumptions are off, glazed collectors could be added in 
series, or substituted entirely.

A whole different option would be heat pump water heaters, running at nite 
for the next days hot water. If the cabins have AC--[surely not at summer 
camp!], that is used almost every nite, de-superheaters would give free hot 
water and increase AC efficiency.

note to Bill-- thanks for the compliment. Guess I'm way out of the box now 
!?

Ken Schaal
www.commonwealthsolar.com

----- Original Message ----- 
From: "Darryl Thayer" <daryl_solar at yahoo.com>
To: <RE-wrenches at topica.com>
Sent: Saturday, March 24, 2007 6:03 AM
Subject: Re: Hot water at summer camp [RE-wrenches]

>
> Hello
> My understanding is that as CO2 desoloves in water it
> becomes acid.  As this acid passes through the
> limetone of soil and rock it becomes CaCO3? This makes
> hard water.  As the water is heated the CaCO
> precipates as the hard water products.
>
> When I am concerned with overheating and stagnation, I
> use a closed water drainback system.  I am concerned
> with usnig antifreeze in stagnation systems because
> the antifreeze breaks down and becomes acid.  Just
> heating water does not.  The closed water drain back
> system must be properly drain when the pump shuts
> down.  These systems survive here in Minnesota, they
> cost as much as antifreeze systems.
>
> Darryl
> --- Ken Schaal <ken at commonwealthsolar.com> wrote:
>
>>
>> Acid neutralizer tanks are on p.2937 of the curent
>> Grainger catalog #398.
>> Limestone [ marble chips] raises the ph. As it does
>> so, it dissolves and
>> could thus precipitate if conditions are right.The
>> rate at which it
>> dissolves is a function of the water ph, and the
>> amount of flow. In a hot
>> copper pipe, or collector, it will form a coating
>> which is both protective
>> and somewhat inhibiting of conduction.
>> Here in the flatlands of the SE, central Va. with
>> shallow 50 wells in sandy
>> soil we have a ph about 5.5. Up in the mountains
>> with limestone formations,
>> it's less of a problem.
>>
>>
>>
>>
>> ----- Original Message ----- 
>> From: "Bill Loesch" <solar1online at charter.net>
>> To: <RE-wrenches at topica.com>
>> Sent: Friday, March 23, 2007 8:00 AM
>> Subject: Re: Hot water at summer camp [RE-wrenches]
>>
>>
>> >
>> > Ken,
>> >
>> > I have never heard of the marble chips technique
>> before. Do I understand
>> > that the marble chemically reacts with the acid
>> water as well as becomes a
>> > precipitate site for hard water scale? If there is
>> a chemical reaction,
>> > how
>> > long does the marble last?
>> >
>> > My compliments for thinking outside of the box.
>> >
>> > Is this marble tank something you home brew or is
>> it commercially
>> > available?
>> > Details please.
>> >
>> > Thanks again,
>> >
>> > Bill Loesch
>> > Solar 1 - Saint Louis Solar
>> > 314 631 1094
>> >
>> > ----- Original Message ----- 
>> > From: "Ken Schaal" <ken at commonwealthsolar.com>
>> > To: <RE-wrenches at topica.com>
>> > Sent: Thursday, March 22, 2007 6:32 AM
>> > Subject: Re: Hot water at summer camp
>> [RE-wrenches]
>> >
>> >
>> >>
>> >> A simple solution to copper corrosion due to acid
>> water is to install a
>> >> neutralizer tank, which uses marble chips to
>> raise the ph. Thicker copper
>> >> will only delay the problem.
>> >> There will be more lime deposits to precipitate
>> onto very hot surfaces,
>> > like
>> >> coffee makers, which can be cleaned with vinegar.
>> For boilers, and batch
>> >> heaters subject to high temps or stagnation,
>> appropriately placed valves
>> >> will facilitate cleaning with acid.
>> >>
>> >> One of the many reasons to use drainback systems,
>> especially now that
>> >> very
>> >> low wattage pumps with high head are available.
>> >>
>> >> Ken
>> >>
>> >>
>> >>
>> >> ----- Original Message ----- 
>> >> From: "Tom Lane" <tom at ecs-solar.com>
>> >> To: <RE-wrenches at topica.com>
>> >> Sent: Wednesday, March 21, 2007 8:26 AM
>> >> Subject: Re: Hot water at summer camp
>> [RE-wrenches]
>> >>
>> >>
>> >> >
>> >> > Hi All,
>> >> > I strongly recommend the SunEarth Copper Heart
>> versus the Progressive
>> > Tube
>> >> > (TCT) PT-40. The TCT PT-40 uses a .030 copper
>> sheet that is welded to
>> > form
>> >> > a tube. We have had lots of problems with this
>> leaking in agressive
>> > water.
>> >> > The Copper Heart  uses extruded .058 DWV copper
>> pipe--almost twice as
>> >> > thick. I suggest a Rheem or Rudd 80 or 120
>> gallon wrap around heat
>> >> > exchange tank if the water is agressive(low
>> ph., iron oxides, CO2 or
>> >> > O2,
>> >> > etc.. with a SunEarth or AET Drainback or
>> pressurized glycol system.
>> >> > Gator Tom
>> >> >
>>
>>
>> - - - -
>> To send a message: RE-wrenches at topica.com
>>
>> Archive of previous messages:
>> http://lists.topica.com/lists/RE-wrenches/read
>>
>> List rules & how to change your email address:
>> www.mrsharkey.com/wrenches/etiquette.php
>>
>> Check out participant bios:
>> www.mrsharkey.com/wrenches/
>>
>> Hosted by Home Power magazine
>>
>> Moderator: michael.welch at homepower.com
>>
>>
>>
>>
>>
>
>
>
>
> ____________________________________________________________________________________
> Bored stiff? Loosen up...
> Download and play hundreds of games for free on Yahoo! Games.
> http://games.yahoo.com/games/front
>
>
> - - - -
> To send a message: RE-wrenches at topica.com
>
> Archive of previous messages: 
> http://lists.topica.com/lists/RE-wrenches/read
>
> List rules & how to change your email address: 
> www.mrsharkey.com/wrenches/etiquette.php
>
> Check out participant bios: www.mrsharkey.com/wrenches/
>
> Hosted by Home Power magazine
>
> Moderator: michael.welch at homepower.com
>
> 

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://lists.topica.com/lists/RE-wrenches/read

List rules & how to change your email address: www.mrsharkey.com/wrenches/etiquette.php

Check out participant bios: www.mrsharkey.com/wrenches/

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael.welch at homepower.com

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

For Topica's complete suite of email marketing solutions visit:
http://www.topica.com/?p=TEXFOOTER
--^----------------------------------------------------------------

</x-flowed>