Make a Solar Furnace

Solar energy is easy to harvest wherever the sun shines, but Charles Curnutt's solar furnace makes harvesting solar energy a feasable and cheap task for anyone with basic shop skills. Start on the path towards renewable energy and learn how to make a solar furnace with this article.
By the MOTHER EARTH NEWS editors
July/August 1978

The backside of the Curnutt solar furnace may look like 'the running gears of a grasshopper" but it's simple, rugged and troublefree.
MOTHER EARTH NEWS STAFF
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Sometimes there just ain't no justice. Take solar energy, for instance: Here we have a extremely diffused form of energy (the sun shines brightly and often enough to be important anywhere most of us really care to live).

Which means — now that we've all started to realize that solar really is the energy source of the future — that our society should be launching a massive program designed to [1] develop the use of the sun's rays on a crash basis, and [2] promote this use on as decentralized a scale as possible. That is: [A] All our big government agencies and giant corporations and large foundations should be pouring money, staff, and technology into solar energy research at the expense of shale oil, nuclear, etc., development; and [B] top priority should be given to the conception and manufacture of smallscale hardware that you can install in your own back yard to make your family energy selfsufficient, instead of to the design and construction of monster equipment that only large utilities and overstuffed government bureaus can afford and control.

Right? Right. That's what should be done. Unfortunately for us all, however, that's not the way society seems to work these days. Because — No. 1 — the U.S. government and every other major government in the world plus all the giant corporations plus all the large foundations are still squandering billions of dollars on shale oil development and nuclear development and the development of other "dead horses" for every million they're investing in solar energy. And — No. 2 —what little is being spent on solar projects is being spent almost entirety on research designed to put the control of solar power in the hands of the already-big, the already-rich, and the already-powerful at the expense of all the world's "little people" (that's you and me, folks).

(A wonderful example of the duplicity of our elected officials in this area: Little Jimmy Carter zipped around the country on May 3 — Sun Day — this year giving glowing speeches about the future of solar energy here in the United States. Everybody knows that, because it was widely reported in the newspapers and on the evening TV news. What wasn't so widely reported, however, is the fact that — just before leaving the White House to make those speeches — the same Little Jimmy Carter rejected a Department of Energy proposal to add $100 million to the federal government's paltry solar energy research budget; a budget, of course, which is dwarfed by the funds appropriated to the shale oil, nuclear, etc., boondoggles. That's called "telling the troops what they want to hear while cutting them off at the knees".)

It is extremely refreshing, then, to pay a visit to Twentynine Palms, California (as two of MOTHER EARTH NEWS' staffers did in the 1970s) to meet a fellow named Charles Curnutt.

Because — while our President is jetting about saying one thing and doing another, while our government and big corporations and fat foundations are pouring billions into the wrong kind of development of the wrong sources of energy; and while all the vested interests of the world seem determined to hand solar energy (if and when they decide to let it happen) to themselves on a silver platter — ol' Charles has just rolled up his sleeves and made a solar energy breakthrough — for the little fellow.

Oh, in some respects (especially when compared to the grandiose schemes proposed by the "big boys") it ain't much to look at: just 100 mirrors mounted on a tracking frame so they all reflect sunlight onto a makeshift boiler stuck out on the end of a 12-foot boom. And that boiler, in turn, is hooked up to a homemade horse-and-a-half steam engine.

Nothin' new about any of that. Archimedes was reflecting enough sunlight with polished bronze shields to set ships afire as early as 215 B.C. And a Frenchman haywired a 100 square-foot parabolic reflector to a boiler well enough to run a steam engine-driven printing press away back in 1880. So the basic ideas behind Mr. Curnutt's work are, as they say, "as old as the hills."

Ah, but the way that Charles has put those ideas together! That's where the real genius comes in. Such simplicity! Such low cost! Such a straightforward way for the average Joe to harness solar energy right out on the patio or over behind the henhouse!

Of course, anyone who knows Charles Curnutt would have expected no less. Because Charles only designs and manufactures what some folks in the business think is the finest, highest quality, and most rebuildable motorcycle shock absorbers being sold today. This is a man, in other words, who understands — indeed, who has set the standards for — some of the simplest, most rugged, most reliable, and most costeffective hardware that anybody anywhere in the world is currently producing.

It was only natural then — while the government, big corporation, and big foundation "experts" were crying about the terrible expense and complexity of solar energy research and development — for Curnutt to just go ahead quietly and build his rig. A rig hardly more complex than a piece of angle iron, but capable of automatically tracking the sun and producing 6,200 watts of power, all for an investment of just $250 in materials and a week or so of the most rudimentary shopwork.

And that's important news. Far more important than anything coming from any of the "big boys" now thrashing about in the solar energy field. Because — with just a little refinement and a little tinkering — Charles Curnutt's tracking solar furnace probably can be used to drive, say, a 5-hp steam engine; or heat water far more efficiently for an active solar heating system than any flat-plate collector so far devised; or, or, or: the potential boggles the mind. Especially when anyone with any shop skills at all can construct the basic Curnutt furnace (and, remember, that basic furnace automatically tracks the sun) in just a few days and for a cost of just $250 in materials.

But the really important news is that Charles Curnutt doesn't especially want to "cash in" on his development. Oh, sure, if he's forced to, he may go into production with some of the rig's components (such as the tracking mechanism) simply to get the idea out into more folks' hands. Still, the fact is that's not what Charles actually wants to do.

What he actually wants to do is make his design freely available to anyone who wants to build and use it. (Take that, vested interests!) So, MOTHER EARTH NEWS' devoted band of researchers constructed and tested their own version of Charles' tracking solar furnace. They built their own home made steam engines and furiously ran to earth every lead they can find on small mass-produced steam-driven power, plants. And they did everything else in their power to research and refine and develop Mr. Curnutt's solar furnace. (All with Charles Curnutt's blessings, of course.) You can see the plans for the Curnutt Solar Furnace in one of our articles.  


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Post a comment below.

 

Aaron_9
3/19/2007 9:04:06 PM
Anyone with any shop skills at all will be able to construct the basic Curnutt furnace, you say. And that certainly evokes such rousing can-do spirit. Indeed, a fine demonstration of concept. Nevertheless, and at the risk of ideological heresy, I would like to open the discussion to planning the next level: In order to promote significant change, what is needed is installation and finance, much the same as if ordering from Sears, with clear savings at the bottom line. Now, savings given costs amortized over time, would justify the purchase as an investment. But savings, the greater, sooner and more immediate the better, would make for a truly revolutionary killer application for maximum impact upon a mass market. And that might be possible, if at all, by two means: First of all, maximal cost effectiveness of the system, but also the best possible and longest terms of finance, in order to transform cost advantage when amortized into immediate lower monthly costs that no one will be able to turn down. If the above can be worked out in any feasible detail, then you will be well on the way to an air tight business plan with an excellent management team, in order to prospect for the requisite capitalization.








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