Sandra wrote:
> This is similar to what the Conservation Coop uses for heat.
I don't mean to get into a my-system-is-better-than-your-system thing, but
I'd like to point out the difference between radiant heating and conductive
/ convective heating. It may help someone design a house.
Before I get into that I'd also like to support passive solar design. I
think it is possible to design a house for most, if not any, climate that
can be completely heated with solar heat, especially if the occupants are
wiling to deal with some temperature fluctuation. If supplemental heat was
desird or necessary, Id lookinto some form of radiant heating (wood stove,
solar heated mass, etc.)
The big difference between our systems is that your building heats the air
with the heat in the water and then moves (?) the air into and around the
room. We are heating the building (floor) directly with the water. We
aren't heating the air which is one of the best insulators. The air
temperature is about 65 with the comfort more like 69 or 70. The unheated
upstairs stays a couple degrees cooler than the down stairs, unlike most
houses where the hot air rises to the ceiling or upstairs. Lower air
temperature means greater efficiency because less heat is lost through the
insulation; this is why it is reccommended that you "turn your thermostat
down at night".
Comfort comes from a few factors: air temperature, surrounding surfaces
temperatures, air movement, humidity, etc. With systems that heat the air
(convective heating) the goal is to get enough warm air in the room so that
the air around your body feels warm. With radiant heating systems
(including wood stoves) a warm mass radiates heat to everything (including
your body) within line of sight of the mass.
I feel like I'm throwing out a lot of words but not really saying what I
want. So, let me just say that in general radiant heating is more efficent
(and more comfortable) than convective heating - for reasons that you may
know if you are interested about how heating systems work, and don't need
to hear from me if you aren't interested : ) And also, that solar energy
(passive and active) can be put to great use for radiant heating. I would
do it differently next time, but I'd stick to passive solar design and
solar (assisted) radiant back up heat.
More tired than I should be to be writing this ; )
Eric:
Sandra wrote:
> On Mon, 29 Mar 1999, eric + michiko wrote:
> >
> > I built the system myself, so there is no brand name except on individual
> > parts. We are heating the floors of our down stairs (880 s.f.) and not
> > heating the upstairs (so far this seems okay, never getting more than a
> > couple degrees cooler than down stairs). We are using a domestic 50 gal.
> > natural gas hot water heater with a heat exchanger to provide the heat.
We
> > were told that it would provide plenty of BTU compared to our heating
> > needs. This seems correct, as we have had no problems with insufficient
> > hot water - actually, the system usually only runs at night when we're
> > asleep adn not using hot water.
>
> This is similar to what the Conservation Coop uses for heat. Each unit has
> a separately metered gas water heater. If I'm understanding it right, the
> heated water is sent through pipes and air is blown over the pipes and
> into the apartment through ceiling level vents. We don't know how well
> this works yet as the passive solar heating of the apartment has kept it
> warmer than what we are used to. We do know someone else in the building
> who finds they rarely have to turn on the heat at all through the winter.
> Fresh air is brought in through an electric powered heat recovery
> ventilation system.
>
> It seems a good halfway there system. Passive solar has been incorporated
> into the design. Right now full sun comes into the apartment through all
> windows and reaches right to the back walls of the aprtment. I think that
> in a few weeks to a month from now, no direct sun will come in through the
> two largest windows. The balcony above us will shade the two largest
> windows through the hottest part of the summer.
>
> sph
>
> Sandra P. Hoffman
> [EMAIL PROTECTED]
> http://www.flora.org/sandra/
>
>
