Solar Area Heat

[Mark42]

Solar heat. Sounds so easy. But I haven't been able to find a system that does what I want.

My home has hot water baseboard heat, not a good system for supplementing with solar because the system operates at water temps around 185*, well above what solar panels ability . But I can add a solar hot water heater for the tap water with an oil fired backup. That could save a few dollars over the years. And it produces hot tap water 365 days a year.

What I really want is to use solar heat to heat the home during the sunny winter days, and use the oil furnace for heating at night or cloudy days. I think a solar heat system designed to heat radiant floor systems would work with recessed wall heaters. If you're not familiar with recessed wall heaters, they are a radiator in a box that fits inside a wall between studs with a grill face and fan that turns on automatically via a thermo switch. (Toe kick radiators are another variation that go under kitchen cabnets.)

I could add a large recessed wall heaters in three or four stategic locations on the first floor and use the solar hot water during the day to offset the baseboard heat. Seeing as hot air rises, some of the excess heat would rise upstairs warming that area too. If the indoor temps could be run up to the high 70's, there would be some thermal mass to keep the house warm durning the evening (I hope!)

In the evening, when the house temperatures are lower, the upstairs bedrooms will be heated by the oil furnace alone.

I have not been able to find a system that comes with all these parts that I know will work together well. If solar heated water can be used in radiant floor heat system, it should work with with the recessed wall heaters.

Another option is to use the central AC to distribute hot air. The house has central AC, with the air handler in the attic. A radiator could be added to the air box and let the AC fan blow heated air through the house. Just not sure if the air will cool off by the time it comes out the vents.

Anything I could add would help reduce the oil bill. I burn about 1200 gallons of heating oil a year. It would be nice to cut that by 1/3 or 1/2.

If I could find a system that would work for me, I would be willing to tap the home equity loan to pay for it, knowing it is saving me money from the start.

Anyone have solar assisted heat systems in their house? Does it provide a significant amount of hot water or area heat?

 

[JB]

Re: Solar Area Heat

What is the temp of water input to the heating system you have, Mark? Why couldn't you preheat that water with solar collectors?

When I lived in MN I used solar collector to warm air and feed it direrctly into the house by gravity on the south side of the house. Even when the outside temp was in the negative range the air coming from the collector was 80-90*. Saved a lot of oil.

 

[mthieme]

Re: Solar Area Heat

I assume you mean solar water heaters. Solar water heaters will produce 185 degrees. Matter of fact, there are newer glass tube designs that will actually produce steam.
I have a proposal somewhere which has a brochure. I'll see if I can scare it up and give you the company information.

Storing the hot water would be an issue.
They also have hot water heaters which integrate into the system.

 

[Mark42]

Re: Solar Area Heat

What is the temp of water input to the heating system you have, Mark? Why couldn't you preheat that water with solar collectors?

When I lived in MN I used solar collector to warm air and feed it direrctly into the house by gravity on the south side of the house. Even when the outside temp was in the negative range the air coming from the collector was 80-90*. Saved a lot of oil.

Water leaves system at about 185*, and returns about 160 or so. I haven't found any collectors that will produce the volum of high temp water needed to work with a baseboard system. Might be there, but I just havent found it.

 

[Mark42]

Re: Solar Area Heat

I assume you mean solar water heaters. Solar water heaters will produce 185 degrees. Matter of fact, there are newer glass tube designs that will actually produce steam.
I have a proposal somewhere which has a brochure. I'll see if I can scare it up and give you the company information.

Storing the hot water would be an issue.
They also have hot water heaters which integrate into the system.

I saw the high temp collectors, but none were part of a area heating system, they were used to make hot tap water where there is time to build a storage of hot water. I need something that can be used in an area heating setup. Maybe I'm just not finding the right system.

 

[mthieme]

Re: Solar Area Heat

Bear with me while I find the brochure...it was a heating system.
It used Pex tubing under the floor for radiant heating. It can handle the volume of water.

 

[gonefishie]

Re: Solar Area Heat

http://www.cansolair.com/

About $2500/panel.

Or do it yourself.

http://fame.drobicho.com/solarfurnace/SolarFurnace.html

Search for solar furnace on youtube, there are numerous videos on this subject.

Maybe we can start our own "Iboats solar furnace project". Together we can perfect a system so we can save our heating money for boating. What better tinkerer then boat owner and fisherman.

 

[smclear]

Re: Solar Area Heat

There is a system that does what you are asking - sort of. It switches from solar to electric. Perhaps they do it for gas as well. It's called the EUTEC HYBRID.

You might also got to ASHRAE.org (American Society of Heating, Refrigeration & Air Conditioning for more information. You will certainly have to dig deep but you will probably find what you need there.

Also, try your local ASHRAE organization. If they can't help, no one can. Here is their URL http://www.njashrae.com/

 

[Mark42]

Re: Solar Area Heat

Thanks for those links, I'm checking them out. The one guy with the "build it yourself solar furnace" is a bit of an idiot because his website will only show the photos if you use firefox as the browser. Oh well....

 

[mthieme]

Re: Solar Area Heat

Okay, I finally found that proposal. The company that sent it to me was Radiant Floor Company, Inc. out of Barton, VT. Here's their URL http://www.radiantcompany.com/
They have some nice brochures.
My proposal included a solar collector made by Seido, pex radiant tubing, and a 79 gallon solar storage tank with optional heating coils (backup).
The proposal seemed very reasonable.
This type of system would be easy to combine/integrate with geothermal.

 

[Kiwi Phil]

Re: Solar Area Heat

We are real big in solar water heaters here in Australia.
They are completely self contained....pretty well designed....all with electric boosters (thermostatically controlled)
Rather than go in to detail, let me know if you hit a "wall" with ideas and I will get you the tech data.

When in the UK, I noticed people have wall-radiators in every room.....with a gate valve on them (tap).
The hot water travels thru the house, heating the radiators that have their gate valves open.
The water is initially heated with electricity or gas or oil fired furnace.

To introduce solar heated water is very simple.

The New Zealanders are big on wet-backs.

1. That is a wood or coal fired enclosed heater (with glass opening door), installed in a living room with the chimney exposed in the room (not in a wall cavity) so you get heat from not only the heater, but also the chimney.
The "wet-back" bit is because....they are plumbed into to hot water system, so the fire also heats water, and when it boils, they have an overflow out the roof to let off pressure.

2. They also have a "chippy", which is a very narrow wood or coal fired stove-come-heater, installed beside the cooking stove in a kitchen (same height, enameled), with sufficient area on top to put maybe a kettle and pot......once again a wet-back (plumbed to heat water).

Once again, to connect a solar system to them is simple.

These ideas can't be new.....you must have them already.

(see photo below) In the backgroud is my neighbours house, and on the roof is his solar system.....and that is a complete unit.....no other tanks etc.....that's it.
That tank on top would keep a family of 6+ in hot water....you couldn't use it as fast as you heat it.

Cheers
Phillip

 

[craze1cars]

Re: Solar Area Heat

Alternative #2 to possibly consider: Geothermal. This is essentially a passive solar heat system, it takes heat from the constant underground temperature deep below the frost line (if you want the ultimate thermal mass heat collector, look no further than THE EARTH), and utilizing a heat pump it moves that heat from the big warm rock we all live on into and/or out of the house as needed 365/24/7, whether outside temp is -40 or +100F, and whether it's sunny, cloudy, or dark.

I had a http://www.waterfurnace.com/ brand setup installed into my 35 year old home about 3 years ago, and I couldn't be happier. Mine is a refrigerator-sized unit that sits in the basement...replaces both the outside central A/C unit and the inside furnace/air handler. Heats and cools/dehumidifies the house year round. It creates hot water as a byproduct, which gets dumped into my domestic hot water heater. Stupid thing was creating so much excess hot water last winter that the high temp safety kept shutting that portion of the system down to prevent overheating. So this year I'm putting that excess free hot water to good use, by installing radiant floor heat under my sunroom floor and will circulate it through the floor via pex/circulator pump/thermostatic control that I got from http://www.radiantcompany.com/. I'm expecting that I will be able to eliminate the only remaining electric baseboard heaters in my home this winter (from that sunroom), which will save me even more on this winter's heating bills.

Overall so far, my annual utility bills have dropped by about 30% to 40% compared to my old air-to-air heat pump system. The entire Water Furnace unit is dead silent and takes absolutely zero maintenance. There is no outside unit, no chimney, no nothing. Just a quiet refridgerator-type hum in the furnace room. They recommend a routine cleaning/inspection once every 5 years, and just keep the air filter clean and otherwise ignore it.

Waterfurnace also sells geothermal boilers if you'd prefer a more dedicated hot water system rather than forced air...and they have a combination unit that does forced air AND boiler that might be nice for your mixed setup: http://www.waterfurnace.com/products.aspx?prd=Synergy3D

This was the best investment I ever made in my home, bar none. No matter what you do, solar or something different, make sure you check for local utility rate, state, and federal tax assistance. At the time I got about 20% of my system paid for by my fellow tax payers. In today's energy "crisis" there are probably even more opportunities to get tax incentives and breaks...maybe even grants. So do lots of research before you spend your own money. You might be able to buy much of it with other people's money! In fact I just noticed right there on the homepage of the waterfurnace site they're announcing a brand new $2,000 tax credit from the feds for any new installs. This credit was not available when I did mine, but I assure you I've saved about that much on my utility bills over the past 3 years, so no loss...and then there's resale value.

I continue to be stunned when the majority of new homes built today still have gas fired or electric furnaces, or air-to-air heat pumps, and central outside a/c units as primary heating/cooling systems and separate domestic hot water systems. For just a touch more money up front they could go with an all-inclusive geothermal unit. Those people could save tens of thousands over the life of the home...and have greater resale if they choose to sell before the system pays itself back. Most builders don't even KNOW about this stuff, much less offer it as an option. Despite the fact that these types of systems have been around since the 1970's...definitely proven technology. Then again my neighbor's new home was just built last year with a similar unit to what I bought, so maybe this stuff is finally starting to catch on slowly with today's skyrocketing energy prices.

Good luck!

 

[Kiwi Phil]

Re: Solar Area Heat

craze1cars
My friend around the corner comes from Belgium.
He talks of this form of heating-cooling he had in his home in Belgium 20yrs back.
Apparently it is the perfect solution for any situation outside the tropics.
Maybe you should look closely at it Mark.
Cheers
Phillip