[Greenbuilding] Opinions on electric tankless HW heaters?

[Carmine Vasile]

Steve: Tests funded by Virginia power show wastewater heat recovery combined with a HPWH keeps the tank's upper element off during long hot showers; thereby keeping the EF near the COP. 
Frank: I can refute "Nick's idea that they only manufacture 13KW tank-less hot 
water heaters." because I installed a 15 kW unit made by Keltech in 1996. It still uses our existing 150-Amp service installed over 2 decades ago. 
   Also, you seem to have missed my point, our system's been saving 50 to 60 mmBtu/year (14.5 to 17.5 MWH/yr) since 1906 compared to the original oil/electric hybrid system like those installed 20-30 years ago in millions of homes and apartment houses. AND and it's Solar-PV ready. 
    With DHR, we only need 10kW to take a hot shower and heat our house. To do this I simply removed a 20-Amp fuse from our 60 Amp Accutemp C150 tankless heater made by Keltech.  
Carmine
P.S. You can read the report @ gfxtechnology.com/tests.html 

Date: Wed, 20 Apr 2011 11:27:25 -0700
From: steve at tjiang.org
To: greenbuilding at lists.bioenergylists.org
CC: Greenbuilding at bioenergylists.org
Subject: Re: [Greenbuilding] Opinions on electric tankless HW heaters?

Depending on the source of generation, heat pump water heaters have roughly the same carbon footprint as gas water heater.  However if you power using electricity from renewables (wind) HPWH is significantly better. My local utility offers the wind option, so I went with the HPWH with solar preheat.  Even if one were to use a Drain heat recovery, HPWH is still the best alternative.
<snipped>
On Wed, Apr 20, 2011 at 11:04 AM, Frank Tettemer <frank at livingsol.com> wrote:

Hi All,

<snipped>

I can't vouch for Nick's idea that they only manufacture 13KW tank-less hot water heaters.  
<snipped>

Yes, Carmine, if we only look at the almighty dollar, and compare costs of various methods of heating domestic hot water, or heating hot water for distribution into household heating, the electric devices all end up costing less to purchase and to operate, in the initial assessment.




Giving regard to overall embodied energy of construction of the domestic hot water system, and associated energy of electrical production and transmission over a decade or two, however, the question arises as to how this all pans out over the coming decade or two.  Looking at a comparison of economics, via using the dollar as the unit of measure is way too short-sighted. It is misleading and hides the truth.


<snipped>



Frank Tettemer

Living Sol ~ Building and Design

www.livingsol.com

613 756 3884 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.bioenergylists.org/pipermail/greenbuilding_lists.bioenergylists.org/attachments/20110420/84249d15/attachment-0001.html>