An A-frame solar water heater concept

[Nick Pine]

. ---- . . . . 30 F . . . . . pond . .-----------. ---- 12' . s 4' . 12' 10.4' . s .

[nicksanspam]

Thank you for counting.

The only big risk is the plastic pool losing strength at 130 F, and there are solutions for that. I go overboard on the "mights" to avoid ignorant people like you raising angry challenges to 300-year-old settled physics.

Nick

[~^Johnny^~]

[News]

LOL, that was good. Nothing personal Nick. :-)

[Ed Earl Ross]

Perhaps a scale model would help settle the mights, coulds and maybes.

[nicksanspam]

EEs abandoned models 20 years ago in favor of simulations, and they don't do simulations for simple systems. Any sufficiently advanced technology appears to be magic, and the less you know, the more it seems to be magic. George Ghio measures risistors in amps, so a large part of the world is magic to him.

Nick

[Ranieri]

SAT: 780 math / 410 verbal

[Ed Earl Ross]

If thermal simulation software is available, by all means, use it.

[George Ghio]

You used the word "Might" 8 times, "Could" 3 times, "If" 3 times, with a "Maybe" and "Somehow" once each.

"Could" it be that you "Might" be proposing that "If" "Somehow" you "Maybe" actually built one you could prove your point without using those words that only confirm that you are in fact just guessing.

[News]

Nick

I read the first paragraph and there was nothing to tell me what all this was about, so I stopped reading. What is the function of the A frame? Then I may read the rest of it.

[George Ghio]

Nick,

You want someone else to do the work. I suggest that you do the work.

The words you use indicate that you are just guessing.

I have the greatest faith in your maths and the physics. The questions are; "Can you prove your theory? Can you in fact build this? Test it? Prove it? Present the results in plain English?

Ignorance generates words like "Might" "Could" "If" "Maybe" "Somehow".

You have presented a theory riddled with doubts.

It is now time to remove the doubts.

Go for it.

[George Ghio]

There is no magic involved when a Rheostat is clearly rated by the manufacturer in amps. I did not make the said Rheostat. I did not rate the Rheostat. I commented on the fact that it was rated in amps as a point of interest.

Now, can you prove your theory with a working unit or not.

[Derek Broughton]

And your problem is??? In a stand-alone greenhouse, you don't have a serious problem if it springs a leak. If it's in your house, you sure do.

[nicksanspam]

Harry Chickpea becomes unpleasant:

Since you ask, I'll comment. The pond above is much more efficient than a pipe in the attic, and it's a draindown system with no exposed water to freeze at night.

Just hot water for showers. The "special greenhouse" might cost $200.

What does that mean?

That might happen north of the Arctic circle :-)

Unpretentious is nice :-)

The staff of the b?

Vegetable gardens don't reflect much sun...

....6 is the garden? Looks like your ascii art got corrupted.

Attwood's $30 pumps have a 3 year guarantee and a 600 hour lifetime.

Nice, altho this requires more pump power than a horizontal pond above a tank with a spiral pipe heat exchanger in the bottom which leaves the water level of the supply and return pipes just below the pond when the pump isn't running. What would you use for a pump and a tank, vs a $98 EZ-set setup?

Nice. You might turn the pump on with Grainger's $8 2E247 snap-disc thermostat in a 1 liter soda bottle (closed above 130 F and open below

115) and turn it off with Grainger's $10 2E365 thermostat (closed below 120 and open above 140) sensing the water temp, if you plan to use a pressurized flat PE pipe spiral as the cold water heat exchanger.

You might pressurize the hot water, unless you live in the basement.

Sounds like work. You mightr say more about this compost process. I did address the cloudy and short days, using actual numbers :-)

Same for the A-frame, with most of the water on the ground.

Sounds familiar.

"Work!" -- Maynard G. Krebs

I disagree.

Nick

[Harry Chickpea]

Gotta laugh. Note the concept of putting water near the peak of a triangular prism to absorb and store heat. This wonderous idea is presented by the same Nickie that pooh-poohed the idea of inexpensively preheating water for a domestic water heater via the simple expedient of placing a 4" pipe underneath and along the ridgeline of a roof. IIRC, his comments were along the lines of what if it leaks, what if it freezes? Yet, he has no comment or solution for the same questions about his own Nickie special design.

Nick would have people construct a special A-frame greenhouse instead, to attempt to capture enough heat to warm an entire house, making the cost/benefit ratio of heating water to the same temperature totally impractical, especially on those cold winter days when 90% cloud cover can be common for weeks at a time. Maybe if Nick hurries, he can still get a job for NASA designing a solar powered outhouse to be towed behind the shuttle.

Now - half tongue-in-cheek, and half-serious, I present an alternative. Cost-wise, a more simple alternative to A frame plan "A" might be the less pretentious plan "b," where a b shape holds a tank or pool at the base (on the ground), contained within strawbales, and a more or less vertical wall of inexpensive construction grade 2" x4" lumber forms the staff of the b, partly braced by the tank and strawbales. This structure would be on the south side of a house, with a vegetable garden just south of the structure.

1 clear plastic 2 clear plastic 3 black shadecloth 4 black plastic 5 insulation and frame 6 winterime tempered herbs cloche Sun > > 12345 ///// I ///// I ///// I ///// IHouse ///// I ///// I ///// plastic pla I ///// straw straw stic p I // 6/ pool or tank straw l I // /straw straw straw astic I garden south // /ground ground ground north house

The southern side of that b wall would be double glazed with plastic, while the north side of the wall would have black plastic and black shadecloth over insulation and a simple frame. The wall might even tilt, like an italic letter b for a better solar angle. Cold water from the bottom of the tank would be pumped by a low volume pump (bilge pump?) to the top manifold and allowed to trickle down through the shadecloth (which would spread and even the flow) and over the black plastic, underneath the first closely-spaced layer of plastic glazing. Since the pump would be controlled by a thermostat or solar sensor at the top of the b, it would only run when it could accumulate heat energy, and no water would be exposed to the cooling effects of night air or have to be drained or pumped without benefit. The heated water drips into and is allowed to accumulate on the top of the tank, thus preserving a greater delta T between the pumped water and the solar collector, increasing efficiency.

Hot water for the house is taken from the top of the tank, and the return pipe enters below mid-level in multiple low-flow horizontal outlets to help preserve the stratification.

The staw bale insulation for the pool or tank could be seeded with fertilizer or dried manure during the fall in preparation for the coldest part of the winter. During that period a small amount of water would be allowed to saturate the inner layer of straw, setting up an exothermic composting process underneath the pool that would be buffered by, and add to the heat of, the pool of water during those cloudy and short days that Nick's design fails to address.

With this design, the weight of the large amount of water safely rests on straw which is on the ground, without requiring an expensive and possibly dangerous permanent structure. The covered pool or tank is simply enshrouded in hay and leaves for the winter, and an outer covering of plastic prevents that material from being blown away or saturated with water from late fall rains or melting snow. The issue of freezing is avoided with the simple expedient of a small drainback hole in the pipe or hose from the pump to the top of the frame.

When spring arrives, the plastic, shadecloth, and insulaton are removed from the frame, the hay from the south side of the tank is spread as compost and mulch, and a layer of clear plastic replaced to form a low tent along the south side of the tank, for use as a cloche/greenhouse in starting seedlings for the garden. (A smaller cloche is shown in the diagram, where a shelf allows midwinter growth of herbs in the area beneath where the water has to drain back into the tank.) Once the spring seedings are safely started, the plastic is again removed. The plastic might be used during the summer for water catchment or to solar sterilize parts of the garden. In early summer, the frame is used to support pole beans, the bulk of the straw is spread, and the tank or pool allowed to cool and supply water to the garden during parched periods. The outflow of the gutters of the house are redirected to keep this pool as filled as possible and reduce watering costs. After the August/September dry spell, the pool will be empty, and the final remaining straw and manure can be removed and set out as winter mulch for the garden. The pool is then remounted on fresh straw, and any rainwater from the roof again channeled into it to help fill it.

Come fall, the vines are removed, the plastic is remounted and the process is repeated.

This design is superior to Nicks in that it has

1. far lower cost
2. far greater safety
3. far simpler and easier construction
4. year around use compared to seasonal use
5. no problems with freezing
6. secondary heat source for cold cloudy days
7. lower pumping costs per unit of useful heat
8. no structural permits and inspection required
9. less impact from vandalism
10. less environmental impact
11. portability
12. lack of acompanying psuedomath justification

[Harry Chickpea]

It isn't my problem. As I pointed out to Nick at the time, a 4" pipe contains enough thermal mass, and the location is inherently warmer than the rest of the attic, to preclude freezing in all but the most extreme climates, and allowing a small cushion of air at the top for expansion would resolve the issue even if it did freeze. The pipe would be no more or less likely to spring a leak than any other pipe. I suggest that you and Nick might want to remember that people have plumbing and even bathtubs on the second floors of their homes, and condos and apartments and office buildings have plumbing that reaches to the sky. Somehow, they survive.

Compare the likelihood of standard pipe leaking in a properly designed and protected tempering tank system to the potential for catastrophic leaks in "a 4'x12' shallow pond at the top and 2 poly film water ducts along the north and south edges to avoid wind sliding and overturning.." contained in a minimally protected A frame covered in plastic. Can you say "BB gun?" Can you say "mouse nibble?" Mice would find such a structure a nice winter home. Poly film - pipe. Poly film - pipe. Hmmm.

Nope. I don't have a problem.

[William.Deans]

Greetings Nick,

The real question is if more women will sleep with you because you use "solar energy" than will run screaming because you have a huge A-Frame in your yard.

Let us know how it turns out, William

[Derek Broughton]

....

What do you consider "the most extreme climates"? Most of the US, and practically all of Canada, are subject to regular conditions _well_ under freezing, and we do NOT have plumbing along the ridgelines of our roofs. To prevent ice-damming, attics are kept as cold as possible, and all plumbing is kept below the insulation. If your attic is warm enough in winter to prevent a pipe freezing, you're wasting too much energy.

I haven't a clue (and don't really care) if Nick's idea is sound, but his objection to a 4" pipe under the ridgeline of a roof certainly is.

[Anthony Matonak]

Well, the design is made public through this forum and it doesn't look like a demonstration/test version would be either difficult or expensive to build. Anyone could build it and tell us how it does or does not perform. It need not be Nick. Certainly, there must be someone with enough time on their hands to do such a thing.

Anthony

[Cosmopolite]

< snipped for brevity >

I agree with this sentiment.

It would be better for everyone if these theoretical projects were actually built and tested, with all data posted, before someone invests their time and money for construction and then finds out that the return on investment is insufficient.

There are times when practice does not fulfill, what theory promises.