updated 1/25/96
Solar + boiler gives radiant heat
Can you use Solar Energy to Heat your
Home all Winter?
Solar + boiler gives radiant heat
© Copyright 2000 From "Ask Mr. Solar" Column Published Feb. 2000 Backhome Magazine
Hello Charlie
My wife and I are planning to begin building our home within the next 2 years, and we were wondering if it would be feasible to heat the house using the Thermomax solar water heating tubes in conjunction with a radiant floor system?
The house will be a very efficient off-grid home with roughly 2,500 square feet of floor space, R-50 walls and roof, and plenty of thermal mass. It's actually called a monolithic dome . . . . . . How many tubes would be required and how big of a storage tank should be used? Would it be best to have separate systems, or have a "combined" system using only one tank with multiple coils?
Thanks for your help! As more of our plans start taking shape, the more I can see that off-grid living using renewable energy is a viable option - and we're getting excited about it!
Thanks again for your help and the wonderfully informative and helpful web-site!
Chris
Hello Chris
As you already know Radiant heat is the way to go with your new home as it is MUCH more economical than using space heaters. We have found out here at the DO IT that we have reduced our fuel consumption by 30% due to the fact that we use a 94% efficient boiler to heat our water where as our space heaters were real energy hogs using only 65% of the fuel to heat our home. Now we are incorporating our Thermomax heat tubes in conjunction with our boiler and this should cut our cost much more. What we are doing is to use the heated water from our Thermomax solar panels in a closed circuit to raise the temperature of our boiler so that we do not have to use as much propane. I do NOT feel that multi coils inside a tank is a good idea as there is a possibility of build up on the pipes and then they do not operate as designed. Please note the picture of this type of system.
The above is a very simple drawing of how you can incorporate solar heating to the greatest advantage in conjunction with your new or addition of solar heating.
Simply what you are doing is heating your water with your solar panels and then returning this water to an external heat exchanger. You use a heat exchanger here so that you will not mix the solar heated water which normally contains a freeze proof additive with your portable water. We feel that the external heat exchanger is the most economical.
From the heat exchanger it goes to a 100 gallon or larger insulated storage tank (here you can use your present hot water tank). From this tank the return loop of your heating area with potable water such as your floor heating loop is added. Then the hot water with the added solar heat is then sent to your Polaris boiler.
From your boiler which may or may not add heat to the water, depending on the input of heat from the solar, it sends the proper temperature water to your floor heating system.
What Is A Solar Power Wall
© Copyright 1996 By Charlie Collins From "Ask Mr. Solar" Column Published 1/18/96 Daily Spectrum
Subject - Solar Electrical "Power Wall" Question from Sarah Guyton & Nick Pine > Internet Dear Mr. Solar:
Question:What advancements have been made (recently) in the field of solar electricity? Thanks! Sara. and then Nick Pine told me about Today an engineer told me that he was at a DOE review meeting yesterday in Washington, DC. One of the speakers got up and showed the audience a PV panel with a line cord coming out of the back and a 110 VAC plug. He then plugged the cord into a wall socket and put the panel near a window and measured the power being fed back into the building's AC supply. Can you find anything about this?
Mr. Solar: Hi Sara & Nick,
These two questions came together in the net and here is what I have found out.
This is in production in Europe as a business associate of mine just returned and reports " In Holland they already have this system in operation. When I went to Niece, France last month and saw this technology. The Utility Company pays the homeowner per kilowatt hour for the electricity their wall produces."
In October, DOE held a PVBONUS program review in Washington D.C. Solar Design Associates, under contract to DOE and in collaboration with Solarex, is developing a proof of concept PV panel that produces up to 120 watts of power at 120 Volts and 60 cycles (standard US AC power). This could plug directly into a standard receptacle and deliver power to the user/owner on their side of the electric meter.
Solar Design Associates is an environmentally aware architectural firm which has specialized in photovoltaic/renewable energy buildings for at least a decade, and which is now developing an "AC" solar module in conjunction with Solarex. The AC module is actually nothing more than a DC module with a small inverter integrated with it. It's been developed under the PV:Bonus program, funded partially by DOE, and is now in the process of commercial introduction.
This multi-year effort Solar Design Associates will produce an integrated photovoltaic architectural curtain wall system for commercial buildings, enabling all building surfaces both wall and roofs to generate electricity.
Solarex is calling the product the "PowerWall" line. The first offerings in the line are modules designed specifically for incorporation in curtain walls, which are the sheer wall systems you see on many modern office buildings. The PowerWall modules replace the glass or other sheet material used in a curtain wall. The PowerWall is developed to be compatible with the curtain wall framing. PowerWall modules are available in AC and DC models, with outputs up to 250 watts.
While these units are not yet commercially available, they are under test and will be available in the Spring of 1996. A 9 kW system utilizing 36 of these panels will be operational in Atlanta, Georgia at the 1996 Summer Olympics.
Can you use Solar Energy to Heat your Home all Winter?
© Copyright 1992 By Charlie Collins From "Ask Mr. Solar" Column Published 12/8/92 Daily Spectrum
Question: Please explain the differences in electrical storage batteries for use in home power for storage.
Jeremy Aldrich, Cane Beds, Az.
Mr. Solar: Jeremy, you can use the energy from the sun to heat your home if you have a large enough heat collectors and storage system.
First you need to realize that there may be three to five days here in southern Utah and northern Arizona that the sun doesn't shine, and therefore you will need to have a collector that will generate more heat than you will need to use in a twenty- four hour period in order to accumulate extra heat. Naturally you will need a storage system that will carry you for those cloudy days. Of course you can build in a back-up system such as a wood stove to use on cloudy days, which will be more economical than extra large collectors and extra storage.
There are a couple of ways to collect the heat from the sun. One way would be to have an enclosed envelope of air which would collect the heat, then you move it in to the storage area with fans. Another way would be to heat water in a very large hot water collector, then move it through pipes in to your storage area.
After you have collected your warm air or water you will need to store it so you can use it as needed. Probably the simplest storage system would be to use rocks. You can heat them and when you need the heat you then blow air across the rocks to move the warm air to the area that you wish to heat.
On the "Do- It Homestead" we have a greenhouse connected to our winter living area. The 200 square foot greenhouse warms up when the sun shines and it heats our living area of 600 square feet very nicely. As a back-up we use a wood stove when the sun isn't shinning.
So Jeremy you see it is possible to heat your home with the sun's heat, however it takes a little planning and a lot of insulation.