Solar heating

[taylorkh]

Since my acreage is small but is still out in the country (although the parasites - subdivisions - are getting closer) I guess this is the least off topic place for this..

Is anyone here doing the solar heating (domestic water or whole house) thing?

or

Does anyone know of any good solar energy discussion boards? I have found a couple but they seem a little sluggish (lame?) not the volume and quality of posts I see here.

I just finished cutting and stacking 12 cords of wood from the remains after a neighbor had 10 acres of timber harvested (and now replanted :-)) Once that is burned my goal is to be at least solar heated and perhaps solar air conditioned.

Regards,

Ken

[Bob]

tailorkh,

I have solar water pre-heating from 2 panels (about 3x6 ft) with thermo-syphon tanks). I'm located on So Calif around 34 deg latitude.

Pro's
The system basically ellimates the use of our conventional gas water heater on all by a few days per year. Many months the main item on the gas bill was a $4 charge for meter rental. A thermostatic mixing valve is absolutely necessary because the water from the solar is often too hot, and temp varies widely with weather/season.

Con's:
Tanks errode just like conventional water heater tanks, but faster because of the extreme heat. I think buying ordinary electric hot waters for the tanks may be the least expensive replacements.
Water in the panels can freeze and distroy the panel in-ards. Another, cold temp, thermostatic valve, is needed to bleed off water for this. Those seem to last about 5 years.

Sorry, I don't have a reference for a solar forum. This forum is hard to beat. Kudos to Hobart an those who moderate this forum.

Bob

ps. I also have a green house that helps house heat loss in winter. It can become a furnace in summer without mitigation. email via forum if U wish.

[Rocket Flier]

4x10 solar water heater. Course in the summer, the water is 100+ coming into the house so it's not much needed then. I have been receiving Home Power magazine for many years now and they recently had a article on solar heating in a cold climate. Many stories of people $30,000 away from the grid putting that money into a home system instead.

http://www.homepower.com/home/

[T>D>C]

Bob,

Do you actually use the water that is circulated through the pannels?

Could you run coils through your standard water heater and put an antifreeze mix in the solar system (like the heat pump water heaters) and use your standard water heater as a heat exchanger? Ex. the fluid in the solar system circulates through you panels, picking up the suns energy then releases it (the heat from the sun) into the water in the water heater tank. I would assume an anti-freeze mix using distilled water would also prevent tank erosion. Like the system on cars.

[Bob]

T>C>D,

My system does circulate the domestic water thru the panels as part of the thermo syphon set up. Distilled and anit-freeze would work for the thermo-syphon part ... but then I need a heat exchanger, and maybe a pump. Seems like the same villans of heat and chemestry are sitll at work in the heat exhanger ... with less obivous and more nasty results of a leak.

Tayorkh,
(emailed me)
Sounds like you are way ahead of me on the tech stuff. Sorry I can't cite a forum. Hobat uses vBulletin for this forum (best forum I know of) and might have some leads to other forums for solar.

Bob

[Rocket Flier]

My original system used a dc circulator and a thermal release valve. If the panel got too cold (because the circulator was solar powered, it didn't run at night) the valve at the outlet of the panel would open and allow tank water to warm the panel.

Aside from the water waste, we experianced a freeze which burst a tube within the collector. We replaced the system with an ac ciculator which has several sensors and a controller. If the tank is cooler than the panel, the pump turns on. As well as if the collector is too cool.

We had also received a quote on a anti-freeze system, but did not want to worry about corrosion all the time.

I did google search on "forum solar heating" but those didn't appear to have much activity. There is a newsgroup
http://groups.google.com/group/alt.solar.thermal
but with a bit of spam/spure to wade through. There are several yahoo groups:
http://groups.yahoo.com/search?query=solar+heating

[whateg0]

...If the panel got too cold the valve at the outlet of the panel would open and allow tank water to warm the panel...

Just a question from the ignorant...

If the warm water from the tank is used to keep the panel warm, doesn't that kinda defeat the purpose of the solar heating in the first place? Could some sort of system be devised that would simply drain the water from the panel when it got below X°, and then let it fill and circulate after it got above X°?

Dave

[2manyprojects]

http://aetsolar.com/
I'm going to heat my shop with a drainback system I bought used, but is just like the one shown on this site. If you poke around they have examples of the different types of systems and plumbing diagrams here.

[2manyprojects]

If you do an internet search use Solar Collector instead of Solar Panel to get water systems...

[Rocket Flier]

Just a question from the ignorant...

If the warm water from the tank is used to keep the panel warm, doesn't that kinda defeat the purpose of the solar heating in the first place? Could some sort of system be devised that would simply drain the water from the panel when it got below X°, and then let it fill and circulate after it got above X°?

Dave

http://www.azsolarcenter.com/technology/solarh20.html

Ok, a bit long for a basic overview, there is a table at the bottom.

To answer your question in short, yes it is inefficient to heat water to keep the panel from freezing. The simplicity of the system for the climate is the justification. Only a handful of freezing nights. Closed loop so you only have the tank, a circulator pump, and the collector.

[blumoon]

maybe not the right spot to interject this but we have a cooling system we made from 1 1/2 poly pipe and an old 4 core radiator, small pump and fan. Blows air about 40 degrees all the time. We use about a 0 degree antifreez mix. Its a pretty simple system.

[pfatz]

Tell me more about your cooling system. I have intended to set up a heating system using a radiator for a long time. It seems like a good idea.

Thanks EdH

[dsw]

As far as cooling I worked in a house last year that used a "geothermal hetaing and cooling system. For heating it works on a heatpump principal. For cooling it's simply a well with a pump, radiator/heatexchanger, and a fan and a drain well. To cool 55F ground water is pumped up and thru the radiator. The fan, standard ac duct system blows over the coils to cool the air. The water is then dumped into the return well. Inexpensive to run and easy to keep the house cool. Definately a system I would look at for my home.

I under stand that the same company that installed the system can also run lines in to a stream or lake to cool the water. Its a closed system as opposed to an open system like the house had.

[whateg0]

I saw something on TV about a zero footprint house or something like that. They had a massive concrete wall in the middle of the house that was used to moderate the temps. In the summer, for example, the concrete would absorb the heat during the day. In the winter, it would do the same, and then radiate some of it back into the air at night. Something like that, anyway. Sounded kinda neat. Don't have a clue if it's effective.

Dave

[scfaster]

Some folks in these parts have been burying pipe in the ground for geo cooling. The ground is always 50-55.