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John: The physics you have "seen" relates to conversion efficiency -- not site energy use or annual operating efficiency, which is difficult to calculate because it includes cycling losses, heat distribution losses, stack losses, etc. <div> For example, from May of 1994 to May of 1995 (the last year we used an oil-fired, tankless-coil space & water heater) we used 37,232 kWh of site-energy; electricity + 700 gallons of home heating oil worth about $2800 today. We had a <span style="font-size: 10pt; ">with a DHR system; n</span><span style="font-size: 10pt; ">o natural gas or propane. </span></div><div> The year after replacing the 20-year old oil system with a triac-controlled, tankless water heater we consumed
22,762 kWh.</div><div> Site energy savings was 14,470 kWh (49.3 million Btu).</div><div> Site-air pollution was eliminated.</div><div> With today's global warming, a 20,000 kWh S<span style="font-size: 10pt; ">olar PV system or windmill would reduce out site energy costs to zero, with no power plant pollution.</span></div><div><br></div><div>Happy Holidays</div><div>Dr. Carmine F. Vasile, </div><div>Ph.D. Electrophysics</div><div>gfxtechnology.com <br><br><div><div id="SkyDrivePlaceholder"></div><hr id="stopSpelling">Subject: Re: [Greenbuilding] Triac Thermostats<br>To: gfx-ch@msn.com; greenbuilding@lists.bioenergylists.org<br>From: jfstraube@gmail.com<br>Date: Thu, 22 Dec 2011 00:48:31 +0000<br><br>
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As far as any physics I have seen, electric resistance water heaters and baseboards are both 100% efficient. Modulating the output does nothing to improve the efficiency. <br>The efficiency of the grid is around 30%, so electric resistance heat is around 30% efficient. <br>Use a heat pump at COP of 3 and you are now around 90% efficient. <br><br>I won't comment on oil heat since this is a small and rapidly shrinking form of heat. <br><div>Sent wirelessly from my BlackBerry device on the Bell network.</div><hr><div><b>From: </b> Carmine Vasile <gfx-ch@msn.com>
</div><div><b>Date: </b>Wed, 21 Dec 2011 18:27:24 -0500</div><div><b>To: </b><jfstraube@gmail.com>; GB Forum<greenbuilding@lists.bioenergylists.org></div><div><b>Subject: </b>RE: [Greenbuilding] Triac Thermostats</div><div><br></div><div dir="ltr">
John: You are referring to electric resistance heating not electric hot-water heating, which can be twice as efficient, cheaper than oil, and far more comfortable. "Exact same energy" will not be delivered because resistance baseboard heating is far more wasteful. I've used both.<div>Happy Holiidays</div><div>Carmine</div><div>gfxtechnology.com <br><br><div><div id="ecxSkyDrivePlaceholder"></div><hr id="ecxstopSpelling">Date: Mon, 19 Dec 2011 20:01:43 -0500<br>From: jfstraube@gmail.com<br>To: greenbuilding@lists.bioenergylists.org<br>Subject: Re: [Greenbuilding] Triac Thermostats<br><br>
Modulating electric heaters WONT save money if you discount the
unproven (and unlikely in my opinion) comfort savings. Exact same
energy will be delivered.<br>
All that changes with any strategy is temperature stability.<br>
It is quite easy to buy a new electronic thermostat for baseboards
that control +/-0.5. The built-in thermostat that often come with
baseboards often are +/-1.5F.<br>
<br>
I sure would not recommend these for most space heating
applications. For special applications, they are neat.<br>
<br>
Dr John Straube, P.Eng.<br>
<a class="ecxmoz-txt-link-abbreviated" href="http://www.BuildingScience.com" target="_blank">www.BuildingScience.com</a><br>
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