[Greenbuilding] Radiant heat boiler--heat exchanger for tiny buildings/families?
Steve Holt
Steve.Holt at enbridge.com
Mon Feb 12 10:06:34 CST 2007
I enjoy reading many threads and occasional reply. I have been involved
hydronic heating systems for many years in Canada, and I have seen what
works and what doesn't. 30 years of hands on service and installations
give me some insight into HVAC.
Niko from Alchemyinc makes a lot of sense.
Multiple tankless units at point of use makes sense in an very large
home with excessive piping runs to each fixture. However this is not a
what I would recommend or install. Primarily, it is very difficult, or
not practical to do, these installations often leaves the equipment very
unserviceable. ( building asthetics are the killer here) Todays high tech
equipment demands more service and it must be accessible.
>From a serviceability and practical perspective, I always recommend a
separate heating and hot water systems. Yes, I will sacrifice some
efficiency in the name of redundancy and reliability. I will also justify
the cost of mechanical equipment, on the cost of the home. A $500,000 home
is worthy of a $40,000 HVAC system.
I also only recommend what I would or do, or use in my own home. My
choices are based on equipment I have serviced, and on equipment I have
seen fail prematurely.
Viessemenn Vitodens is the top of my list for radiant floor heating,
however a very close second is the Weil McLain Ultra. ( Price point and
simplicity moves me to choose the Ultra ) . Both of these boilers will
provide many years of reliable heat for any family. These are two pipe
systems, and the combustion process will not affect the building envelope.
Plumbing, controls, pumps and setup are key. Experienced HVAC Techs are a
must, and they require a strong plumbing background. ITT (Bell and
Gossett owns the bible of hot water heating.) Ask anyone who has attended
the little red school house.
On to hot water, my choice ( Tankless, Takagi, Rheem, Rinnai ) all good
products. Again pick the two pipe modules. In larger homes, with very long
piping runs, pipe in a domestic hot water recirculation line, ( well
insulated ) and install a small circulator pump that cycles on a time /
temperature schedule that meet the customers needs. ( Taco has some
answers for re circulation problems ) I normally will install multiple
units to meet larger hot water demands. Sometimes the addition of storage
or a buffer tanks is a must for some hot water hogs. Pre heat your
domestic hot water if possible, and you have a very reliable system. (
AO Smith wrote the DHW bible )
A great technician and a good engineer are an unbeatable team for your
infloor needs. If you go with the lowest cost, you most likely, will be
sorry.
Two cents from a somewhat green and practical guy.
Steve Holt
416-574-6523
"Carmine Vasile" <gfx-ch at msn.com>
Sent by: greenbuilding-bounces at listserv.repp.org
02/10/2007 05:47 PM
To
chalicenew at earthlink.net, LLile at projsolco.com, dmelchert at earthlink.net,
greenbuilding at listserv.repp.org
cc
Subject
Re: [Greenbuilding] Radiant heat boiler--heat exchanger for tiny
buildings/families?
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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