Hot water at summer camp [RE-wrenches]

[Ken Schaal]

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Holt
Maybe we should back up a bit and ask a few questions.
1-- You said summer camp--June July and Aug? In Texas? Do they even want hot 
water of 120+ ?
Or will it be more like 90-115?

2-- Showers are for 1 hr. -- How many shower heads? flow rate? water 
pressure issues? length of shower? cold water temp?
If we assume 14 kids and two showers at 2gpm ea. for 5min ea, then we have a 
total flow rate of 4gpm and a total on time of 35 min. with a 2 min break 
between showers, for a total draw in less than 50 min of 140 gal of shower 
temp water.

3-- How close are the cabins? You said the solar resource was excellent to 
fair, so it sounds like some are shaded. If the cabins are grouped, maybe 
one system could serve multiple cabins?

Depending on you answers, I'll suggest an appropriate system.

Ken Schaal
CommonWealth Solar,LLC



----- Original Message ----- 
From: "Darryl Thayer" <daryl_solar at yahoo.com>
To: <RE-wrenches at topica.com>
Sent: Sunday, March 18, 2007 12:36 PM
Subject: RE: Hot water at summer camp [RE-wrenches]


>
> Don"t underestimate the tremendous power draw of these
> heaters.  If the campers run out of hot water and they
> start using the 70 amps per leg per cabin this will
> wipe you out fast.
>
> The problems I have had and even in my own house has
> been the temperature changes as you try to shower.
> When the flow rate is steady only one shower and the
> solar is not to hot, the unit will turn on, on medium
> fire, and the user actually adjusts the temperature by
> flow rate.  If the solar is to hot the unit will hunt
> on its own accord with the high limit shutting it off
> and the temp changing.  Now if you add a second
> shower, it comes on and now the temp drops, then the
> first shower adjusts either the flow or the mix (same
> thing) the second shower changes temp and they adjust
> the first then changes temp and they adjust AAAhhhh!
>
> Now I explain this to people who have solar and
> instant water heaters, and that I will not guarantee
> satisfaction, and I still get customers saying it is
> my problem when they are unhappy, and I need to fix
> that.
>
> When people get experience they understand how to
> adjust and do not have two showers on at once and get
> by OK.
>
> Mixing valves will do this for you automatically, but
> they usually fall out of the range of acceptable temp
> range.
> --- Holt Kelly <holtek at sbcglobal.net> wrote:
>
>>
>> Darryl,
>> Could you eleaborate a bit on why the customers were
>> "unhappy" and on
>> the "tricks needed" for uniform temps? The only
>> complaint that I have
>> gotten on electric tankless (besides spinning the
>> meter at 1000rpm)is
>> the loud clicks of the relays during start-up (Eemax
>> brand). Thanks for
>> your input.
>>
>>
>>
>>
>> Darryl Thayer wrote:
>> >
>> > Hello
>> > I agree, except for the back-up heater.  I have
>> > installed up to 70A-240 volt instant heaters with
>> > unhappy customers.  I have installed even the
>> TAGAI
>> > which is rated for solar with unhappy customers
>> > because of the tricks that must be played to get a
>> > shower of uniform temperature.  If the goal is
>> > reasonable showers then use a tank type back up
>> > heater.
>> > Darryl
 I have been asked to design a hot water system
>> at
>> > > a summer camp. 21
>> > > > seperate sytems. Hot water for showers is used
>> > > from 4:30pm to 5:30pm(14
>> > > > showers)per system, very little use the rest
>> of
>> > > the day. Solar resource
>> > > > is excellent to fair. My initial thoughts were
>> 2-
>> > > 40gal passive
>> > > > collectors with an electric tankless backup
>> (need
>> > > to keep maintenance to
>> > > > a minimum). Or possibly Helio-flo with single
>> > > tank. Any thoughts out
>> > > > there?
>> > > >
>> > > > Holt E. Kelly
>> > > > Holtek Fireplace & Solar Products
>> > > > Waco, TX.


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