Solar hot water space heating question:

[trof]

I can find a little info on the web, but nothing that addresses this specific situation.

My daughter lives near Boston in a 100 year old Victorian 2-story.
They heat with a gas fired boiler and radiators.
Couldn't they use roof-mounted solar panels to heat the water going to the boiler and the radiators?

[John1956PA]

1. That's a pipe dream.

The panels would produce a modest amount of energy on a sunny day, but not enough to heat a house. On days when snow covers the panels, no energy would be produced.

[trof]

11. Is that a pun? 'Pipe dream'? Water? Radiators?

:rofl:

[John1956PA]

23. Thanks, I thought you might be ticked by what could be construed as flippancy.

But, since I had the chance to be No. 1, I could not resist. Seriously, though, I think that it is cost prohibitive to try solar systems on houses which were not designed to make maximum use of the modest winter sunlight which we experience here in the northern latitudes.

[izquierdista]

2. Terrible location

New England is not a prime area for solar energy. That said, there are still possibilities as solar installations are being used in Germany which has a similarly poor climate. If the house has reasonably good southern exposure and the roof is well sloped, like a lot of Victorians, it could be a possibility. Unlikely to be enough available solar energy to heat the whole house, but perhaps for domestic hot water.

[jpak]

6. It works in Maine....

http://www.solarhouse.com/index2.htm

Our south-facing roof is where the sun does its work. There are two areas side-by-side: solar thermal for hot water/heating and photovoltaic for electricity.

Solar thermal:

The water that is circulated in the roof is stored in two 500-gallon tanks in the basement. When the temperature on the roof is 10 degrees higher than the water stored in the tanks, pumps circulate the stored water to the roof to be heated. The pumps shut down when both temperatures are equal. Even during periods of high thin clouds the system will work, though not as efficiently. The diagram on the right is from industry guru Michael Potts. Two pumps are required to raise the water from the basement to the top of the roof. One of them turns off after the natural siphoning process takes over. A visual indicator registers how much water is being circulated in the system--great fun to watch.

Here is one of our two "megatanks" used to store the solar-heated water. My wife Debbi quickly embraced the idea as well as the tank. We are now harvesting the sun's energy to keep the interior warm. This is a significant milestone in our lives--a goal finally achieved after 25 years of dreaming and planning.

<snip>

During the coldest days of winter, the sun seems to shine with unusual brilliance. While neighbors worry about a rising heating bill (we know the feeling having once lived in an electric-heated house), we can accept the sun's gift without any state or federal taxes.

The solar-heated water also provides the basis of our hot tap water as well as circulating through the radiant tubing in the first and second floors of the house. Propane provides any necessary backup as well as gas for cooking and clothes drying.

<more>

[izquierdista]

8. Nice article

That house has quite a bit of roof for solar exposure. I'm pretty sure an old Victorian in the middle of the big city would be at a disadvantage though.

[jpak]

9. Yup - there are a lot of variables to consider

The cheapest thing to do would be to get a pellet stove.

A 50,000 BTU Harman XXV costs ~$3100 plus installation. They look good and can heat an entire house (with a few door fans).

http://www.harmanstoves.com/callouts.asp?id=45

I have a 40k BTU Harman Accentra - and it does heat the whole house (in Maine).

http://www.harmanstoves.com/specifications.asp?id=12

[trof]

14. Trust me, they will not get a pellet stove. POLLUTION???

Come ON.

[jpak]

20. Pellet stoves are highly efficient and do not produce smoke or creosote.

You don't need a traditional chimney (just a 4 inch exhaust pipe) and you do not need to clean the exhaust pipe.

Natural gas stoves produce 0.7 grams of particulates per hour.

Pellet stoves produce 1.0-1.2 grams per hour

Wood stoves (EPA certified) produce 5.5-8.5 g/hr

Old School wood stoves produce 30-50 g/hr

Pellet stoves are as clean as they get...

[trof]

13. Why would you be 'pretty sure'?

It happens they have a huge south facing roof with no shade obstructions.
They are not in downtown Boston.
They're in a village nearby.
jeez

[izquierdista]

19. Maybe it would work then

Most Victorians were built with not one forethought as to solar exposure. And from my times in Boston, shade trees seemed quite popular, especially in the suburbs. The likelihood that one would have a good patch of roof space, with a 45-degree slope, south facing unshaded exposure would seem small. But if they have that, then by all means, go for it!

[nykym]

10. Just a side note.

I knew someone who used to work for ConEd in managment back in my college days, and solar was in its infancy, what he said was that you would not see much progress until the figured out how to bill you for using the SUN! LOL!!!

[trof]

12. Wrong.

[NJmaverick]

3. While I am not an expert on this subject

From what I have heard, solar is used to pre-heat the hot water you use. As for the boiler and radiator system, that's a closed system and I don't really see a way that solar could be added. The furnace boils the water and it turns to steam. This steam then goes to the radiators where it condenses and is gravity fed back into the furnace. Usually you don't want to change that water more than you have to, as fresh water contains oxygen that will corrode the pipes and furnace.

On the plus side the solar hot water will work the best in the summer (when the sun is the strongest), which is a big plus over solar for heating (that has it's biggest demand when the sun is it's weakest).

[trof]

15. Not a steam system. A hot water system.

And I know the difference.
Nothing 'boils' in their system.
It's very easy to tap into a closed system and supply it with water that's already hot.

[jpak]

4. The answer is yes (if they have an unobstructed south-facing roof)

It can be plumbed into their existing hot water system...

Mass. doesn't have a rebate for solar hot water, but they have a 15% state tax credit (up to $1000) for solar hot water heaters - that's in addition to the 30% federal tax credit (due to expire this year thanks to solar hatin' republics).

They also have a 0% solar loan program too (up to $10,000, seven year payback period)...

http://64.233.169.104/search?q=cache:_h651_1fZh8J:www.cetonline.org/Renewables/Incentives.pdf+massachusetts+solar+hot+water+heater+rebate&hl=en&ct=clnk&cd=9&gl=us

There are also solar hot air systems (developed in Newfoundland where winter sun is practically nonexistent)...

http://www.cansolair.com/okeefeTestResults.htm

http://grandeprairie.kijiji.ca/c-buy-and-sell-business-industrial-Solar-hot-Air-panels-MADE-IN-CANADA-W0QQAdIdZ50795897

[trof]

16. Thank you! Best info yet.

:thumbsup:

[JDPriestly]

5. MIT was heating a house in Mass. in 1973-1974

most days with solar energy. They switched to gas on certain days. Check with MIT. Of course, it was a long time ago. I know this because I saw a presentation by MIT scientists at the First International Energy Conference in London. I think it was January 1974.

[trof]

17. There ya go.

It's doable.

[Webster Green]

7. Here's a site with some info on this stuff..

They describe systems that divert the heat into the hot water supply for domestic hot water, and also into radiant floor systems, rather than radiators for heating, which would require a lot of renovation, but are more efficient. The radiators might be able to be used instead of the floor system. It's a good place to start, as they have basic info on various solar systems and how they are used.
http://solaradiant.com/thermal/

Also check out http://www.fossilfreedom.com/solar-thermal-tubes.html
(This is a site that I built for my brother, and he and I are selling the solar tubes, but frankly, I'm still trying to get up to speed on all this stuff, so I'm no expert on all the ways to configure these systems.)

[trof]

18. OK, that's more to the point.

Obviously they don't want to retrofit this ancient Victorian with hardwood floors to radiant floor heating.
But the radiators are already there.
Why not feed them with solar heated water?
Makes sense to me.

[Webster Green]

21. I'll try to find out more about this specific question..

I'll PM you if I succeed. :hi:

[tinrobot]

22. Not solar, geothermal.

Dig a really deep hole and throw some pipes down there. You'll get more heating from the earth than from the sun, particularly in your area.