tankless water heaters [RE-wrenches]

[Travis Creswell, Ozark Solar]

Hi Jay,

First let me say I have very little experience with standard heating
boilers.  I have played with a lot of steam engine and installed of couple
of Skip Goebles steam fired generators.   I haven't seen any home boilers
much over 90% eff  and the common ones are just over 80%.  From what I have
heard, if you use them to heat water in your residence they can be terribly
inefficient because the efficiency is the peak, not when they are modulated
down to 50% or so as they could be when they are heating water in the
summer.   If you are using a boiler to send water to a "indirect water
heater" the heat exchanger in the indirect tank typically cannot get all the
heat out of the hot water which means you are running a 100,000 BTU boiler
for a 20,000 BTU water heater.  That's fine in the winter but in the summer
when you aren't heating your house your running the boiler just for hot
water that can be bad.

Your typical gas water heater is less than 50% efficient before you figure
any standby losses and of course an electric is 100% efficient before you
figure the stand by losses.

The tankless model from Japan you mention look very promising.  I believe
you are speaking about the Takagi.  It is comparable to the Aquastar 170 in
output but the same size as a 125.  It has no standing pilot and is
electronically modulated unlike the troublesome mechanical system of the
AquaStars.  Powervent is standard as is a freeze protection system  (75 watt
draw, I think?).  Of course it would not be wise to install them outside in
any other place than FL or southern TX as even though the Takagi could
survive the light freeze the rest of your outdoor plumbing would be in
danger unless you heat taped all of it.

Travis

----- Original Message -----
From: "jay peltz" <jay at asis.com>
To: <RE-wrenches at topica.com>
Sent: Monday, March 26, 2001 8:41 AM
Subject: Re: tankless water heaters [RE-wrenches]


> Hi Bob,
>
> Not really a fair comparison as you using electric vs natural gas.
>
> If someone outthere has info on efficiencys then I would love to see it.
All
> the data I have seen points the other way.  Boilers on the other hand are
> getting more effieicent at 95%+, but now you are talking thousands of $$.
>
> There are new models from Japan that are really nice.  They install
outside on
> the wall, ( they have freeze protection built in) so take up no inside
space,
> need no vent ( direct vent) cost about the same as a Aquastar.
>
>
> jay
> Peltz Power
>
> > -
>
> - - - - - - -
> To send a message:
>  RE-wrenches at topica.com
>
> The archive of previous messages:
>  http://www.topica.com/lists/RE-wrenches/
>
> List rules & etiquette:
>  http://www.mrsharkey.com/wrenches/etiquete.htm
>
> To unsubscribe send a message to:
>  RE-wrenches-unsubscribe at topica.com
>
> To check out the other RE-Wrench participants:
>  www.mrsharkey.com/wrenches/index.html
>
> Hosted by Home Power magazine:
>  www.homepower.com
>
> For info contact list moderator by email:
>  michael.welch at homepower.com
>
> ____________________________________________________________
> T O P I C A  -- Learn More. Surf Less.
> Newsletters, Tips and Discussions on Topics You Choose.
> http://www.topica.com/partner/tag01
>
>

- - - - - - -
To send a message:
 RE-wrenches at topica.com

The archive of previous messages: 
 http://www.topica.com/lists/RE-wrenches/

List rules & etiquette:
 http://www.mrsharkey.com/wrenches/etiquete.htm

To unsubscribe send a message to: 
 RE-wrenches-unsubscribe at topica.com

To check out the other RE-Wrench participants:
 www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine: 
 www.homepower.com

For info contact list moderator by email:
 michael.welch at homepower.com

____________________________________________________________
T O P I C A  -- Learn More. Surf Less. 
Newsletters, Tips and Discussions on Topics You Choose.
http://www.topica.com/partner/tag01