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    <p><font face="Verdana">Ah<font face="Verdana">,<font face="Verdana">

            off grid. I see. That makes sense. I wouldn't use it place

            of solar, but <font face="Verdana">we have used it as part

              of one. Obviously we have a <font face="Verdana">tank in

                that application. <font face="Verdana">We have a very

                  good propan<font face="Verdana">e sales person <font

                      face="Verdana">here<font face="Verdana"> who has

                        sold a lot of on demand radiant and hydronic.<font

                          face="Verdana"> It<font face="Verdana">'s <font

                              face="Verdana">almost twice the<font

                                face="Verdana"> <font face="Verdana">cost

                                  per BTU v oil, but t<font

                                    face="Verdana">hey have done very

                                    well on low mainte<font

                                      face="Verdana">nance claims</font>.

                                  </font></font></font></font></font></font></font></font></font></font></font></font></font></font></font><br>

    </p>

    <br>

    <div class="moz-cite-prefix">On 3/20/2018 1:58 PM, Dave Angelini

      Offgrid Solar wrote:<br>

    </div>

    <blockquote type="cite"

      cite="mid:3eae3a515c4ce9af5180c5953fec8831.squirrel@webmail.sti.net">

      <pre wrap="">Chris,

For Offgrid with minerals in the well water, getting the right flow, the

maintenance that is just not there with a tank heater. Tankless are great

for many but if you do add an open loop solar water panel, you need a

tank.... Just not worth it in places like the south west where there is

abundant sunshine. Offgrid in remote places where service is questionable

or unavailable, we go with the most reliable. I steer them that way for

other reasons also..

Dave Angelini Offgrid Solar

"we go where powerlines don't"

<a class="moz-txt-link-freetext" href="http://members.sti.net/offgridsolar/">http://members.sti.net/offgridsolar/</a>

e-mail  <a class="moz-txt-link-abbreviated" href="mailto:offgridsolar@sti.net">offgridsolar@sti.net</a>

text 209 813 0060

</pre>

      <blockquote type="cite">

        <pre wrap="">What are the issues with tankless water heaters?Т  I have heard them

described as having "issues", but I haven't read anything that describes

what they are.Т  They are very popular where I live.Т  Any info? Thanks,

Chris

On 3/20/2018 1:07 PM, Dave Angelini Offgrid Solar wrote:

</pre>

        <blockquote type="cite">

          <pre wrap="">And a big maybe for Offgrid where we like multiple ways to

charge/heat/cool and make hot water. The default method is almost always

the most reliable. For a typical home a 50 gallon propane tank water

heater with a zinc change every 7 years is the norm.

An air to water heat pump, an open loop solar water panel or closed loop

if conditions warrant it are great secondary methods. To me heating

water

with electricity does not work because of winter and is a last thing to

add.A tankless and their issues are near the end of the list. Ground

source heat pumps are even lower to me with very nice prices on

extremely

efficient mini split air source pumps.

I always try and minimize generators but if you need them then it allows

one to have more options.

Dave Angelini Offgrid Solar

"we go where powerlines don't"

<a class="moz-txt-link-freetext" href="http://members.sti.net/offgridsolar/">http://members.sti.net/offgridsolar/</a>

e-mail  <a class="moz-txt-link-abbreviated" href="mailto:offgridsolar@sti.net">offgridsolar@sti.net</a>

text 209 813 0060

</pre>

          <blockquote type="cite">

            <pre wrap="">Maybe. I designed my own house to incorporate this. The most efficient

are

the vertical type, and at 6' the company advertised 20% recovery for

about

$1,300 if I remember correctly. This I'm sure is for a new copper pipe,

and

anyone who's ever taken apart a sewer pipe after a few years will know

all

pipes get a bacterial mat of a couple mm thick. I suspect this might be

a

pretty good insulator. At any rate there is a whole lot of copper

involved

and associated inherent environmental challenges. I can't help but

think

for the house design challenge to accommodate such a long perfectly

vertical pipe and expense another kW or more of solar would offset more

energy.

On Tue, Mar 20, 2018 at 9:50 AM, Drake

&lt;<a class="moz-txt-link-abbreviated" href="mailto:drake.chamberlin@redwoodalliance.org">drake.chamberlin@redwoodalliance.org</a>

</pre>

            <blockquote type="cite">

              <pre wrap="">wrote:

Daniel,

That sounds like an intriguing technology, much along the lines of an

air

to air heat exchanger. Thanks for the recommendation.  These systems

could

keep a lot of CO2 out of the atmosphere if widely used.

Drake

At 10:09 AM 3/19/2018, you wrote:

Content-Type: multipart/alternative;

          boundary="----=_NextPart_000_0077_01D3BF6A.5EF88420"

Content-Language: en-us

Drake,

Have you or the client looked into the drainwater heat recovery units?

They make both a vertical and horizontal mounted version. They just

help

recover the waste heat from shower water going down the drain.

My understanding is that economically they are barely past the

breakeven

point when considering offsetting grid power. If using PV costs as the

benchmark, the economics would be better. If somehow this is off grid,

then

IУЂт\u201aЌт\u201eЂd say itУЂт\u201aЌт\u201eЂs a home run. (Hopefully though this is not

an

all-electric

off-grid building.)

The main benefit, as far as I understand it, is that you can get by

with

a

smaller unit, with a smaller heating element to perform the same task,

OR

you can get much longer showers from the same sized unit. Depending on

the

clients goals, this might be a useful tool to bring into the

situation.

Here are two brand names that I know of.

Vertical mount: renewability

Horizontal mount: ecodrain

I have not used these products, so I cannot endorse any of them, just

though it may be worth consideration.

With Regards,

Daniel Young,

NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90

*From:* RE-wrenches <a class="moz-txt-link-rfc2396E" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">&lt;re-wrenches-bounces@lists.re-wrenches.org&gt;</a> *On

Behalf Of *Drake

*Sent:* Thursday, March 15, 2018 1:00 PM

*To:* RE-wrenches <a class="moz-txt-link-rfc2396E" href="mailto:re-wrenches@lists.re-wrenches.org">&lt;re-wrenches@lists.re-wrenches.org&gt;</a>

*Subject:* Re: [RE-wrenches] Electric Water kWh/ person

This discussion has been a great help. The house is built and the

plumbing

is in, but could be modified. Wood stoves are not a likely solution. I

think we need a different water heating strategy.

Thank you all!

Drake

At 09:21 AM 3/15/2018, you wrote:

Content-Type: multipart/alternative;

  boundary="------------EE4E9806B711DEF636076840"

Content-Language: en-US

This is what I came up with:

The calculation is Q = mcp delta T

Water Temp out =У\u0192т\u20ac\u0161  120

Water Temp in = ground source Temperature @ 50F?

delta T = 70F

m =У\u0192т\u20ac\u0161  mass flow rate.У\u0192т\u20ac\u0161  ASHRAE is the source for this. 20gals

per

person

per day = 20 gallons x 8.34 lbs/gallon =У\u0192т\u20ac\u0161  167lbs/day/person

cp =У\u0192т\u20ac\u0161  1 BTU/lb-degree F

Q = 167 x 1 x 70 = 11,676 BTU/day/person

Divide this by the efficiency of the water heating system (I'll assume

=

.86)У\u0192т\u20ac\u0161  =11,676/.86 = 13, 577 BTU/person/day

convert to kWh if necessarym 13,577/3412 = ~4 kWh/person/day, 120

kWh/month

I checked this against one month and it seems reasonable.

Website assuming ~3.5 family size comes up with @ 400kWh per month.

They

approached it another way with assuming run times.

<a class="moz-txt-link-freetext" href="https://www.google.com/search?safe=active&amp;source=hp&amp;ei=">https://www.google.com/search?safe=active&amp;source=hp&amp;ei=</a>

Z3KqWvXiNsGb5wKJ2Kf4DA&amp;q=electric+water+heater+use+annual+consumption&amp;oq=

electric+water+heater+use+annually&amp;gs_l=psy-ab.1.2.

33i22i29i30k1l3.279.9222.0.12475.35.19.0.7.7.0.451.2360.

0j6j4j0j1.11.0....0...1c.1.64.psy-ab..18.16.1952.0..

0j0i67k1j0i131k1j0i22i30k1.0.CiU8wYZigpI

Chris

On 3/15/2018 8:09 AM, Mike Kocsmiersky wrote:

Barton makes a good point with regards to the incoming ground water

temperature and the amount of heat required to bring it up to shower

temp.

У\u0192т\u20ac\u0161 My recollection is that ASHRAE states 20gal/person/day for the

first

2

people, then 15gpd or 12gpd thereafter.У\u0192т\u20ac\u0161  However those rates vary

wildly

with consumers, from those that never bathe to the high schooler that

needs

3 showers a day.У\u0192т\u20ac\u0161  In the northeast water heating can be up to 19%

of

the

total household energy load for the year.У\u0192т\u20ac\u0161  Also, I would

recommend the

air

source heat pump water heaters if you have significant humidity or an

on

demand unit.У\u0192т\u20ac\u0161  Water tanks are typically under insulated and can

lose

2kWh/day in standby losses.

У\u0192т\u20ac\u0161

Mike Kocsmiersky

Principal

Spirit Solar Inc.

(413) 734-1456

У\u0192т\u20ac\u0161

У\u0192т\u20ac\u0161

У\u0192т\u20ac\u0161

From: Barton Churchill [<a class="moz-txt-link-freetext" href="mailto:barton@solarips.com">mailto:barton@solarips.com</a>

<a class="moz-txt-link-rfc2396E" href="mailto:barton@solarips.com">&lt;barton@solarips.com&gt;</a>]

Sent: Wednesday, March 14, 2018 7:31 PM

To: RE-wrenches

Subject: Re: [RE-wrenches] Electric Water kWh/ person

У\u0192т\u20ac\u0161

You first need to know your ground temperature. Then figure a delta to

100

or so degrees. Most but not all showerheads flow 2.5gpm and showers

are

typically 10 minutes. You can then find a calculator online to

calculate

how many Btus are required to raise water temp for your delta per

gallon.

Convert to kWh, add some contingency and you should be good.У\u0192т\u20ac\u0161

On Wednesday, March 14, 2018, &lt; <a class="moz-txt-link-abbreviated" href="mailto:drake.chamberlin@redwoodalliance.org">drake.chamberlin@redwoodalliance.org</a>&gt;

wrote:

Hello Wrenches,

Is there a good way to estimate the power that will be consumed for

electric water per person per day? We are estimating the amount of

power

that will be used by an all electric duplex, and the water heater

amount

seems high. The current model we have claims 3493 kWh/ year per 26

gallon

tank will be consumed. With the two units, that would add up to 6986

kWh

/

year for hot water, pushing the system size to humongous for a 1300 ft

sq

building.

Does that seem high? There will be a maximum of 2 people per unit.

The owner is considering going to 115 V units with a 15 gallon tanks.

I

think the smaller tank would help, but it would seem that the amount

of

hot

water consumed would be the main issue.

How can we get a good estimate for a per person energy usage for

electric

hot water? Any other suggestions are welcome.

Thank you,

Drake

--

--У\u0192т\u20ac\u0161

Barton Churchill

406.587.5295 &lt;(406)%20587-5295&gt; У\u0192т\u20ac\u0161

2430 North 7th Bozeman, MT 59715

<a class="moz-txt-link-abbreviated" href="http://www.solarips.com">www.solarips.com</a>

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</pre>

            </blockquote>

            <pre wrap="">

--

--

Barton Churchill

406.587.5295

2430 North 7th Bozeman, MT 59715

<a class="moz-txt-link-abbreviated" href="http://www.solarips.com">www.solarips.com</a>

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</pre>

          </blockquote>

          <pre wrap="">

Dave Angelini Offgrid Solar

"we go where powerlines don't"

<a class="moz-txt-link-freetext" href="http://members.sti.net/offgridsolar/">http://members.sti.net/offgridsolar/</a>

e-mail  <a class="moz-txt-link-abbreviated" href="mailto:offgridsolar@sti.net">offgridsolar@sti.net</a>

text 209 813 0060

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 Т Т Т Т Т Т Т Т  Christopher Warfel, PE

 Т Т Т Т Т Т  ENTECH Engineering, Inc.

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Dave Angelini Offgrid Solar

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                    <font size="-1">         Christopher Warfel, PE<br>

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