<div dir="ltr">I had 3 customers that were my data source. unfortunately, I had trouble monitoring the thermal systems and they got tired of me coming over daily to see the runtimes ect one gave up on solar thermal when a leak occurred,  The other two I stopped monitoring because of expenses in the monitoring of the solar thermal.  </div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Mar 15, 2018 at 12:35 PM, cwarfel <span dir="ltr">&lt;<a href="mailto:cwarfel@entech-engineering.com" target="_blank">cwarfel@entech-engineering.com</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

  <div text="#000000" bgcolor="#FFFFFF">

    <p><font face="Verdana">That would be a good analysis to share. I

        can see how it could be <font face="Verdana">poss<font face="Verdana">ible with lo<font face="Verdana">wer module

              costs, but I haven&#39;t seen any studies on this <font face="Verdana">comparison<font face="Verdana">. Chr<font face="Verdana">is</font></font></font></font></font></font></font><br>

    </p><div><div class="h5">

    <br>

    <div class="m_-7367700840129037460moz-cite-prefix">On 3/15/2018 1:17 PM, Darryl Thayer

      wrote:<br>

    </div>

    <blockquote type="cite">

      <div dir="ltr">When I did my study of solar water heating I found

        that PV water heating gave more hot water at a lower cost than

        solar thermal.  the Heatpump water heater was the big winner.  </div>

      <div class="gmail_extra"><br>

        <div class="gmail_quote">On Thu, Mar 15, 2018 at 12:00 PM, Drake

          <span dir="ltr">&lt;<a href="mailto:drake.chamberlin@redwoodalliance.org" target="_blank">drake.chamberlin@<wbr>redwoodalliance.org</a>&gt;</span>

          wrote:<br>

          <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

            <div>

              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.<br>

              <br>

              Thank you all!<br>

              <br>

              Drake <br>

              <br>

              <br>

              <br>

              At 09:21 AM 3/15/2018, you wrote:<br>

              <blockquote type="cite" class="m_-7367700840129037460m_-2933207039044196130cite">Content-Type:

                multipart/alternative;<br>

                 boundary=&quot;------------EE4E980<wbr>6B711DEF636076840&quot;<br>

                Content-Language: en-US<span><br>

                  <br>

                  <font face="Verdana">This is what I came up with:<br>

                  </font><br>

                  <font face="Verdana">The calculation is Q = mcp delta

                    T<br>

                  </font><br>

                </span><font face="Verdana">Water Temp out =Ā  120<br>

                </font><span><br>

                  <font face="Verdana">Water Temp in = ground source

                    Temperature @

                    50F?<br>

                  </font><br>

                  <font face="Verdana">delta T = 70F<br>

                  </font><br>

                </span><font face="Verdana">m =Ā  mass flow rate.Ā 

                  ASHRAE is the

                  source for this. 20gals per person per day = 20

                  gallons x 8.34 lbs/gallon

                  =Ā  167lbs/day/person<br>

                </font><br>

                <font face="Verdana">cp =Ā  1 BTU/lb-degree F<br>

                </font><span><br>

                  <font face="Verdana">Q = 167 x 1 x 70 = 11,676

                    BTU/day/person<br>

                  </font><br>

                </span><font face="Verdana">Divide this by the

                  efficiency of the water heating

                  system (I&#39;ll assume = .86)Ā  =11,676/.86 = 13, 577

                  BTU/person/day<br>

                </font><span><br>

                  <font face="Verdana">convert to kWh if necessarym

                    13,577/3412 = ~4

                    kWh/person/day, 120 kWh/month<br>

                  </font><br>

                  <font face="Verdana">I checked this against one month

                    and it seems

                    reasonable. <br>

                  </font><br>

                  <font face="Verdana">Website assuming ~3.5 family size

                    comes up with @

                    400kWh per month. They approached it another way

                    with assuming run

                    times.<br>

                  </font><br>

                  <font face="Verdana">

                    <a href="https://www.google.com/search?safe=active&amp;source=hp&amp;ei=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" target="_blank">

                      https://www.google.com/search?<wbr>safe=active&amp;source=hp&amp;ei=Z3KqW<wbr>vXiNsGb5wKJ2Kf4DA&amp;q=electric+<wbr>water+heater+use+annual+<wbr>consumption&amp;oq=electric+water+<wbr>heater+use+annually&amp;gs_l=psy-<wbr>ab.1.2.33i22i29i30k1l3.279.<wbr>9222.0.12475.35.19.0.7.7.0.<wbr>451.2360.0j6j4j0j1.11.0....0..<wbr>.1c.1.64.psy-ab..18.16.1952.0.<wbr>.0j0i67k1j0i131k1j0i22i30k1.0.<wbr>CiU8wYZigpI</a>

                    <br>

                  </font><br>

                  <font face="Verdana"><br>

                    Chris<br>

                  </font><br>

                  <font face="Verdana"><br>

                  </font><br>

                  <br>

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

                </span>

                <blockquote type="cite" class="m_-7367700840129037460m_-2933207039044196130cite">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. Ā My

                  recollection is that ASHRAE

                  states 20gal/person/day for the first 2 people, then

                  15gpd or 12gpd

                  thereafter.Ā  However those rates vary wildly with

                  consumers, from

                  those that never bathe to the high schooler that needs

                  3 showers a

                  day.Ā  In the northeast water heating can be up to 19%

                  of the total

                  household energy load for the year.Ā  Also, I would

                  recommend the

                  air source heat pump water heaters if you have

                  significant humidity or an

                  on demand unit.Ā  Water tanks are typically under

                  insulated and can

                  lose 2kWh/day in standby losses.<br>

                  Ā <br>

                  <span>

                    Mike Kocsmiersky<br>

                    Principal<br>

                    Spirit Solar Inc.<br>

                    <a href="tel:%28413%29%20734-1456" value="+14137341456" target="_blank">(413) 734-1456</a><br>

                  </span>

                  Ā <br>

                  Ā <br>

                  Ā <br>

                  <span>

                    <b>From:</b> Barton Churchill

                    [<a href="mailto:barton@solarips.com" target="_blank">mailto:barton@solarips.com</a>]

                    <br>

                    <b>Sent:</b> Wednesday, March 14, 2018 7:31 PM<br>

                    <b>To:</b> RE-wrenches<br>

                    <b>Subject:</b> Re: [RE-wrenches] Electric Water

                    kWh/ person<br>

                  </span>

                  Ā <br>

                  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.Ā

                  <br>

                  <span><br>

                    On Wednesday, March 14, 2018,

                    &lt;<a href="mailto:drake.chamberlin@redwoodalliance.org" target="_blank">

                      drake.chamberlin@redwoodallian<wbr>ce.org</a>&gt;

                    wrote:<br>

                    Hello Wrenches,<br>

                    <br>

                    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. <br>

                    <br>

                    Does that seem high? There will be a maximum of 2

                    people per unit.

                    <br>

                    <br>

                    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. <br>

                    <br>

                    How can we get a good estimate for a per person

                    energy usage for electric

                    hot water? Any other suggestions are welcome.<br>

                    <br>

                    Thank you,<br>

                    <br>

                    Drake<br>

                    <br>

                    <br>

                    <br>

                    -- <br>

                  </span>

                  --Ā <br>

                  Barton Churchill<br>

                  <a href="tel:%28406%29%20587-5295" value="+14065875295" target="_blank">406.587.5295</a> Ā <br>

                  <span>

                    2430 North 7th Bozeman, MT 59715<br>

                    <a href="http://www.solarips.com/" target="_blank">www.solarips.com</a><br>

                    <img alt="Image removed by sender." height="100" width="100">

                    <br>

                  </span>

                  Ā <br>

                  <span><br>

                    <br>

                    <br>

                    <pre>______________________________<wbr>_________________

List sponsored by Redwood Alliance

List Address:

<a href="mailto:RE-wrenches@lists.re-wrenches.org" target="_blank">

RE-wrenches@lists.re-wrenches.<wbr>org</a>

Change listserver email address &amp; settings:

<a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target="_blank">

http://lists.re-wrenches.org/o<wbr>ptions.cgi/re-wrenches-re-wren<wbr>ches.org</a>

List-Archive:

<a href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html" target="_blank">

http://www.mail-archive.com/re<wbr>-wrenches@lists.re-wrenches.or<wbr>g/maillist.html</a>

List rules &amp; etiquette:

<a href="http://www.re-wrenches.org/etiquette.htm" target="_blank">

www.re-wrenches.org/etiquette.<wbr>htm</a>

Check out or update participant bios:

<a href="http://www.members.re-wrenches.org" target="_blank">

www.members.re-wrenches.org</a>

</pre>

                  </span></blockquote>

                <br>

                -- <br>

                <br>

                <font size="2">Ā Ā Ā Ā Ā Ā Ā Ā  Christopher Warfel, PE<br>

                  Ā Ā Ā Ā Ā Ā  ENTECH Engineering, Inc.<span><br>

                    PO Box 871, Block Island, RI 02807<br>

                  </span>

                  Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā Ā  <a href="tel:%28401%29%20466-8978" value="+14014668978" target="_blank">(401)466-8978</a></font><br>

                Ā <br>

                <a href="http://entech-engineering.com" target="_blank">

                  <img alt="EEI logo" height="89" width="201">

                </a> <span><br>

                  <br>

                  <br>

                  ______________________________<wbr>_________________<br>

                  List sponsored by Redwood Alliance<br>

                  <br>

                  List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org" target="_blank">RE-wrenches@lists.re-wrenches.<wbr>org</a><br>

                  <br>

                  Change listserver email address &amp; settings:<br>

                  <a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target="_blank">

                    http://lists.re-wrenches.org/o<wbr>ptions.cgi/re-wrenches-re-wren<wbr>ches.org</a>

                  <br>

                  <br>

                  List-Archive:

                  <a href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html" target="_blank">

                    http://www.mail-archive.com/re<wbr>-wrenches@lists.re-wrenches.or<wbr>g/maillist.html</a>

                  <br>

                  <br>

                  List rules &amp; etiquette:<br>

                  <a href="http://www.re-wrenches.org/etiquette.htm" target="_blank">

                    www.re-wrenches.org/etiquette.<wbr>htm</a><br>

                  <br>

                  Check out or update participant bios:<br>

                  <a href="http://www.members.re-wrenches.org/" target="_blank">

                    www.members.re-wrenches.org</a></span></blockquote>

            </div>

            <br>

            ______________________________<wbr>_________________<br>

            List sponsored by Redwood Alliance<br>

            <br>

            List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org" target="_blank">RE-wrenches@lists.re-wrenches.<wbr>org</a><br>

            <br>

            Change listserver email address &amp; settings:<br>

            <a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" rel="noreferrer" target="_blank">http://lists.re-wrenches.org/o<wbr>ptions.cgi/re-wrenches-re-wren<wbr>ches.org</a><br>

            <br>

            List-Archive: <a href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html" rel="noreferrer" target="_blank">http://www.mail-archive.com/re<wbr>-wrenches@lists.re-wrenches.or<wbr>g/maillist.html</a><br>

            <br>

            List rules &amp; etiquette:<br>

            <a href="http://www.re-wrenches.org/etiquette.htm" rel="noreferrer" target="_blank">www.re-wrenches.org/etiquette.<wbr>htm</a><br>

            <br>

            Check out or update participant bios:<br>

            <a href="http://www.members.re-wrenches.org" rel="noreferrer" target="_blank">www.members.re-wrenches.org</a><br>

            <br>

            <br>

          </blockquote>

        </div>

        <br>

      </div>

      <br>

      <fieldset class="m_-7367700840129037460mimeAttachmentHeader"></fieldset>

      <br>

      <pre>______________________________<wbr>_________________

List sponsored by Redwood Alliance

List Address: <a class="m_-7367700840129037460moz-txt-link-abbreviated" href="mailto:RE-wrenches@lists.re-wrenches.org" target="_blank">RE-wrenches@lists.re-wrenches.<wbr>org</a>

Change listserver email address &amp; settings:

<a class="m_-7367700840129037460moz-txt-link-freetext" href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target="_blank">http://lists.re-wrenches.org/<wbr>options.cgi/re-wrenches-re-<wbr>wrenches.org</a>

List-Archive: <a class="m_-7367700840129037460moz-txt-link-freetext" href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html" target="_blank">http://www.mail-archive.com/<wbr>re-wrenches@lists.re-wrenches.<wbr>org/maillist.html</a>

List rules &amp; etiquette:

<a class="m_-7367700840129037460moz-txt-link-abbreviated" href="http://www.re-wrenches.org/etiquette.htm" target="_blank">www.re-wrenches.org/etiquette.<wbr>htm</a>

Check out or update participant bios:

<a class="m_-7367700840129037460moz-txt-link-abbreviated" href="http://www.members.re-wrenches.org" target="_blank">www.members.re-wrenches.org</a>

</pre>

    </blockquote>

    <br>

    </div></div><div class="m_-7367700840129037460moz-signature">-- <br>

      <div class="m_-7367700840129037460moz-signature"><br>

        <div class="m_-7367700840129037460moz-signature">

          <div class="m_-7367700840129037460moz-signature">

            <div class="m_-7367700840129037460moz-signature">

              <div class="m_-7367700840129037460moz-signature">

                <div class="m_-7367700840129037460moz-signature">

                  <div class="m_-7367700840129037460moz-signature">

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

                             ENTECH Engineering, Inc.<br>

                      PO Box 871, Block Island, RI 02807<br></span>

                                     <a href="tel:(401)%20466-8978" value="+14014668978" target="_blank">(401)466-8978</a></font><br>

                    <div class="m_-7367700840129037460moz-signature"> <br>

                      <a href="http://entech-engineering.com" target="_blank"><img src="cid:part27.C4C26B8E.12CF2C7F@entech-engineering.com" alt="EEI logo" height="89" width="201" border="0"></a> </div>

                  </div>

                </div>

              </div>

            </div>

          </div>

        </div>

      </div>

    </div>

  </div>

<br>______________________________<wbr>_________________<br>

List sponsored by Redwood Alliance<br>

<br>

List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.<wbr>org</a><br>

<br>

Change listserver email address &amp; settings:<br>

<a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" rel="noreferrer" target="_blank">http://lists.re-wrenches.org/<wbr>options.cgi/re-wrenches-re-<wbr>wrenches.org</a><br>

<br>

List-Archive: <a href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html" rel="noreferrer" target="_blank">http://www.mail-archive.com/<wbr>re-wrenches@lists.re-wrenches.<wbr>org/maillist.html</a><br>

<br>

List rules &amp; etiquette:<br>

<a href="http://www.re-wrenches.org/etiquette.htm" rel="noreferrer" target="_blank">www.re-wrenches.org/etiquette.<wbr>htm</a><br>

<br>

Check out or update participant bios:<br>

<a href="http://www.members.re-wrenches.org" rel="noreferrer" target="_blank">www.members.re-wrenches.org</a><br>

<br>

<br></blockquote></div><br></div>