[Greenbuilding] Radiant heat boiler--heat exchanger for tiny buildings/families?

Sat Feb 10 16:47:17 CST 2007

Mary: Since you asked; what does your "greenbuilder/designer" define as 
"overkill"? Does he know  1/3 of California's residential energy usage went 
to heat water in 1991; 80-90% of which went down-the-drain according to the 
CEC PIE Chart @ http://gfxtechnology.com/CEC.pdf? What's changed? Carmine

>From: "Mary Bull - Greenwood Earth Alliance" <chalicenew at earthlink.net>
>Reply-To: "Mary Bull - Greenwood Earth Alliance" <chalicenew at earthlink.net>
>To: "Dr. C.F. Vasile" <gfx-ch at msn.com>,"Lawrence Lile" 
><LLile at projsolco.com>,"David Seth Melchert" 
><dmelchert at earthlink.net>,"Greenbuilder list" 
><greenbuilding at listserv.repp.org>
>Subject: Re: [Greenbuilding] Radiant heat boiler--heat exchanger for tiny 
>buildings/families?
>Date: Sat, 10 Feb 2007 08:31:24 -0800
>
>Dr. Vasile,
>
>I asked our greenbuilder/designer about your heat exchanger, and he said it
>was overkill for applications/buildings our size in our climate and so on
>(our building is a three-story strawbale tower with a 420SF footprint for
>two people on the Sonoma, California, coast). What do you think?
>
>Thanks!
>
>Mary Bull, Co-director
>Greenwood Earth Alliance, Save the Redwoods - Boycott the Gap Campaign
>252 Frederick, San Francisco, CA 94117 http://www.gapsucks.org
>Chalice Farm and Sustainable Living Center, 748 Montgomery Rd, Sebastopol 
>CA
>95472
>415-731-7924 - 415-509-1188 chalicenew at earthlink.net
>
>
>----- Original Message -----
>From: "Dr. C.F. Vasile" <gfx-ch at msn.com>
>To: "Lawrence Lile" <LLile at projsolco.com>; "David Seth Melchert"
><dmelchert at earthlink.net>; "Greenbuilder list"
><greenbuilding at listserv.repp.org>
>Sent: Friday, February 09, 2007 3:12 PM
>Subject: Re: [Greenbuilding] [BULK] Radiant heat boiler
>
>
> > Why are you guys on the "GREEN" Building List; three (3) tankless water
> > heaters are "excessive" because 80-90% of their outputs (shower power &
> > energy) are wasted down-the-drain; when 50%-60% of it could be recycled
> > (www.gfxtechnology.com)!
> >
> > ----- Original Message -----
> > From: "Lawrence Lile" <LLile at projsolco.com>
> > To: "David Seth Melchert" <dmelchert at earthlink.net>; "Greenbuilder list"
> > <greenbuilding at listserv.repp.org>
> > Sent: Tuesday, February 06, 2007 7:33 PM
> > Subject: Re: [Greenbuilding] [BULK] Radiant heat boiler
> >
> >
> > > Well, a shower head is about 3 GPM, you can figure your peak flow from
> > > there.  For the most part, people don't use the shower and the sink at
> > > the same time in one bathroom, and the shower generally can't be used 
>at
> > > the same time as the tub.  You can also figure peak flows from the
> > > number of occupants - are there enough people in the house to take 3
> > > showers at a time?  People may also use the washer and dishwasher at 
>the
> > > same time as a bath.  In my current house, they won't do this more 
>than
> > > once, since we have a wimpy tankless that can't keep up with more than
> > > one load at a go.  Brrr.
> > >
> > > In my new house, a Tagaki jr, model is keeping up with two showers at
> > > once.
> > >
> > >
> > > If these bathrooms are not grouped, or if the kitchen is not nearby,
> > > you'll want two sources of hot water.  A typical tankless heater has
> > > several seconds of delay (My tagaki waits 6 seconds before firing) 
>plus
> > > the long run, can mean minutes of wait to get hot water.  The buffer
> > > tank sounds like a good idea actually - I was considering putting
> > > something like that in a kitchen that has the long run problem.  Add
> > > extra insulation to whatever the manufacturer thought was enough,
> > > because the buffer tank defeats some of the savings associated with 
>the
> > > tankless.
> > >
> > > I can't imagine 3 tankless heaters, seems pretty excessive.  Do the 
>math
> > > and see what you come up with.
> > >
> > >
> > >
> > > Lawrence Lile, P.E., LEED AP
> > >
> > > -----Original Message-----
> > > From: greenbuilding-bounces at listserv.repp.org
> > > [mailto:greenbuilding-bounces at listserv.repp.org] On Behalf Of David 
>Seth
> > > Melchert
> > > Sent: Tuesday, February 06, 2007 6:04 PM
> > > To: Greenbuilder list
> > > Subject: [BULK] [Greenbuilding] Radiant heat boiler
> > > Importance: Low
> > >
> > > We have started a large residential remodel in Orinda, CA. The 2,800 
>sf
> > > house will be heated with radiant floor heat. We were planning to use 
>a
> > > Baxi Luna 330 instant heater for combined radiant and domestic hot
> > > water. I really love the Baxi Luna for its compact design and 
>simplicity
> > >
> > > of installation, not to mention its general high efficiency.
> > >
> > > However we are concerned about its capacity to serve the demands of a 
>3
> > > bath house. The homeowner consulted with a supplier who suggested that 
>5
> > >
> > > gpm, delta 70 degrees is the minimum required, more than the 144,000
> > > BTU's the Baxi Luna provides. Baxi has a new Modula supplemental tank
> > > that holds 21 gallons and serves as a kind of buffer for temporary 
>high
> > > demands. My homeowner is concerned this will not cut it. They are 
>edging
> > >
> > > towards having separate heat sources, such as a Noritz or an efficient
> > > large tank for DHW.
> > >
> > > Here are my questions: how many gpm should we figure for hot water 
>needs
> > >
> > > at any one time, and how often might a family of four run into
> > > insufficient hot water using the Baxi? Would you agree that providing
> > > separate heat sources for radiant and DHW would be the best path?
> > >
> > > Thanks
> > >
> > > Seth Melchert
> > > Oakland CA
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