In standard hot-water tank operations, cold water entering the tank is needed to push hot water to faucets. Assuming that the cold water is 60 degrees, a water tank starting with water at 140 degrees will drop to 100 degrees (roughly body temperature) after only half of the hot water is used. This wouldn't be a problem if only one or two people are needing showers, or if tanks are heated by conventional propane/electrical (i.e. quick) methods, but it would be a difficulty for families using slow solar-heating methods, especially as solar heating doesn't give hot water until late in the day (i.e. cramming all showers toward the evening time).

There are two ways to minimize the problem: provide larger tank and solar-heating units, and/or don't pump cold water into the tank while removing hot water. The second option requires a gravity-feed situation i.e. a water tank in the ceiling above the tub. To make up for lack of water pressure, we can use a larger pipe to the shower head, and then drill larger holes into the showed head. Plus, a shower head directly above our bodies (as opposed to on the wall) could be arranged.

What's the best way to capture heat by sunlight: 1) water running through rows of black metal pipes inside a glass housing, or, 2) water in a glass housing (minus the pipes) equipped with black backing? Although I am not an expert in this field, it seems to me that the second option would be the best method, for virtually all heat captured by the backing will have no place to go but into the water, whereas much heat captured by metal pipes will escape upward into the air before it gets into the liquid. Moreover, it works both ways i.e. during cloudy periods, heat transfers efficiently from hot liquid through the pipe walls (exactly the efficiency we don't want).

I'm only guessing, but the reasons that pipeless methods are not common commercially are two: 1) to eliminate freeze damage (i.e. a tank filled with water will crack due to a freeze), and, 2) city and well-pump water pressures on clear-plastic tanks would damage them and/or increase the risk of leaks.

We can eliminate both problems by not filling a tank, using an automatic shut-off valve of the float kind found in your toilet tank, for example, or the kinds used to automatically open and shut water to livestock tanks. In this way, with a shut off valve between the solar-heated tank water and the well pump, the pressure maintained by a well pump (typically set at 40 psi) is not transferred to the tank water.

A so-called "passive solar heater" consists of a metal tank painted black, having the same flaw as a pipe heater, of heating the top areas of the tank and thereby allowing much solar heat to escape the tank walls before it ever gets into the water.

To build a clear-tank, think fish aquarium; just silicone rigid-plastic pieces together (use good/appropriate silicone), but have the lid removable (i.e. use screws and a rubber gasket). As for types of clear plastic/glazing materials, the website below, in an article on passive heaters, mentions "Du Pont Tedlar-coated fiberglass exterior with Teflon-film interior glazing, acrylic or polycarbonate plastics..." http://www.motherearthnews.com/diy/1984_January_February/Build_an_Integral_Passive_Solar_Water_Heater

Double-paned glass/plastic is advantageous for heat retention but may become counter-productive if humidity gets between the panes (water reflects away almost 10 percent of incoming light). Perhaps if some small holes are drilled into the outer pane, the humidity problem would be solved. Use of a third pane is debatable since every pane reduces the amount of incoming light.

The article above says that "Davis Alternative Technology Associates suggests about 2.5 gallons of water per square foot of glazing as the maximum ratio for good heating." Pipe heaters do not achieve half that much hot water per square foot of solar heater. I don't know about you, but I could have a great shower with just 10 gallons of hot water (mixed with 5-8 gallons of cold), and if needed, I know I can "shower" with one gallon of hot, as I've done it many times (and enjoyed every drop because roughing it makes one appreciate the little that he has). But nothing beat those times when I was building the house in mid-summer and bathed with a bar of soap in the river!

Still, for trib purposes, I don't want to skimp on hot water because I'll be expecting "guests" to come visit me on a permanent basis. In my clear tank design (which I'll build and test soon), I'll shoot for 3 gallons of water per square foot of tank bottom, which works out to a depth of 5 inches. I would therefore set my float-regulated shut-off valve to cut water supply when the water depth is 5 inches (and yet, for a reason to be explained, I'd still make each tank 24 inches deep). If you use a toilet-tank type valve, you can adjust the water depth as easily as bending (by bare hands) the float stem (that's why you should make your tank lid removable).

I imagine good tank dimensions to be 24" deep x 24" wide x 48" long (it would be a good idea to move an "aquarium" this large around (empty) while it's on a rigid wooden platform). Two tanks at these dimensions (16 square feet total), with a 5-inch depth, would contain about 50 U.S. gallons, but on top of these water there would be, say, another 50 gallons, in a fully-insulated storage tank (where the warmed waters are to be stored until used). However, due to an invention that I'm incorporating into the clear-tank design -- the invention is applicable only with clear tanks -- I think 80-100 gallons can be heated with the two tanks alone.

Suppose some hot rocks on the ground could jump into the tank water, then get out and bath in the sun some more, and repeat the process every 30-60 minutes. Wouldn't that be a decent invention? But if we could put those rocks into the tank above the water, and dip them into the water as soon as they get hot, that would be even better, right? Well, I've got a better idea than dipping rocks, because metal heats up much faster.

Energy is always at a maximum when sunlight strikes a surface at 90 degrees (i.e. perpendicular), and while there isn't any one stationary surface that can receive sunlight at that angle for very long, using more than one heated surface makes up for all the losses. You can thereby have a stationary tank, and on a fully-horizontal (i.e. non-tilted) platform, while wasting no sunlight energy due to hour-by-hour and season-by-season changes in the angles of the sun.

Correct me if I'm wrong, but to capture as much solar energy as one 24" x 48" surface tracking the sun all day at 90 degrees, three surfaces are required: A) a 24 x 24 vertical metal plate on the tank's north side, facing south; B) a 24 x 48 hinged metal plate on the east side that can either stand vertically or swing on its hinge to a horizontal position on the tank floor; C) another 24 x 48 hinged metal plate, but on the west side, that can either stand vertically or swing on its hinge to a horizontal position on the tank floor.

Here's how it works. When the sun first rises above the horizon, its (east-to-west) light will penetrate the tank because collector B is in its horizontal position (on the tank floor); at this time B receives zero light. Light can then strike collector C perpendicularly because it will be in its vertical position. During the sun's rise to the noon position, collector C will receive less energy gradually, until, at true/high noon (not clock noon), its surface receives zero light. But precisely the energy levels not obtained by collector C due to the sun's angle will be absorbed by collector B, until at high noon the latter receives maximum/perpendicular light.

The positions in which we find the collectors at noon need re-arranging because collector C will block most afternoon light into the tank. To accomplish the re-arranging, there must be a timer sending electricity to two small winding mechanisms (one on the east, and one on the west, side of the tank). Roughly at high noon, the timer is set to wind a thin metal cord attached to collector B, thus raising it to a vertical position. One minute later, the same timer unwinds another cord attached to collector C, allowing it to drop to the horizontal position. At the end of the day, the situation will be equivalent to one 24 x 48 surface facing the sun all day.

The south-side collector A absorbs most of the south-to-north light passing through the tank, a significant amount in non-summer months (there is miniscule north-to-south light in the northern hemisphere, and none in the United States/Canada).

With all three collectors, 100 percent of light entering the water strikes a submerged black surface! The heat produced is thereby given to the water immediately. But there's more, for all three collectors are 24 inches tall and therefore stand about 18 inches out of the water, wherefore they absorb much sunlight that does not enter the water. In other words, they become super hot, much hotter than the water, for which reason they not only directly transfer some of their heat into the water, but they make the tank's air space hotter than the water so that there is no water-to-air heat loss as long as the sun shines, and even for quite some time after clouds cover the sun!!

Since the collectors B and C are already built to drop into the water, why not drop them several times each day? Each collector can be equipped with a temperature sensor, set to drop a collector upon its reaching a certain hot temperature, thereby unleashing much heat to the water. The collector is then lifted to absorb more heat. Since metal absorbs heat quickly, the collectors may drop into the water many times each day, but since one collector is always in the water, the two will never drop simultaneously so as to conflict with one another.

If you use pipe collectors to heat your water, then the above scenario is impossible and irrelevant. You'll then do well to angle your solar heater toward the sun as best as possible. It would be great if you could rig a platform to automatically follow the sun hour by hour, but so far (early 2007), I don't think the idea exists commercially. The following solar-panel website is helpful for finding the best angles as per your particular latitude, and says that panels/surfaces tracking "the movement of the sun throughout the day can receive 10% (in winter) to 40% (in summer) more energy than fixed panels" (brackets not mine)
http://www.arch.hku.hk/research/BEER/angle.htm

This explains why pipe heaters only heat about one gallon per day (to 140 degrees) per square foot of collector surface. Again, I think pipe collectors are used to eliminate winter freezing, but my choice is a better solar heater for non-winter months, and then a hot-water tank above the wood/corn stove all winter long. After all, the wood/corn stove will no doubt be the primary home-heating method in the trib, so why not use it to heat water? Corn stoves, because they burn all night without the need to get up and load it, will provide hot water also for morning showers (important for some). Of course, we could purchase sufficient solar panels to provide all hot water needs, but that's a very expensive outlay, and I'm trying to save us money here so that we can spend it on other needs instead.

Water in a heater-tank design not using water pressure needs to be circulated to and from the insulated tank by a small/slow pump (preferably a solar-powered pump). Some commercial solar heaters use pumps activated by sunlight (i.e. pumps are purposely designed not to work in cloudy periods), which at first glance sounds perfect. But it's not at all perfect because, during long cloudy periods, water in the heater cools faster than water in the insulated tank, meaning that a pump activated by sunlight after the cloudy period passes can pump colder water into the insulated tank and meanwhile force its hotter waters into the heater. Not good. Clouds could again roll in at just the wrong time and make things worse so that, at the end of the day, the water in the insulated tank may be less than body temperature (i.e. on the cool side) even though the tank achieved hot water at some point(s) in the day.

Another way to activate the pump is according to water temperatures; this method would best have two electrical switches, each turned on and off by temperature sensors. One sensor at the heater turns a switch on (i.e. allows electricity to the pump) only when the water is at a certain temperature (say at 115 degrees). The other sensor is at the insulated tank and turns a switch on only when the temperature is below 115 degrees. In order for the pump to receive electricity, both switches must be on. The problem with this method is that the insulated tank may have cool water at the end of a partly cloudy day even though the heater's water reached 114 degrees (i.e. the temperature didn't quite reach the point at which water transfer to the insulated tank kicked in). However, we should definitely have a second electrical wire to the pump that we can turn on from a manual switch, to transfer water to the insulated tank whenever we deem it advantageous.

A summer choice of heater location (a choice that most city folks don't generally have) might be on the ground and against the west wall of the house (the hottest wall during afternoons and evenings). By not having the heater on the roof or an open area, but instead snuggly against a wall of your home, it'll receive most air currents at reduced speeds. The heat build-up in the western wall will also help to keep the water warm, whereas you won't have that benefit in an open area. The wall can achieve very hot temperatures, too hot to the touch at times, and because it's already filled with insulation, it will retain heat after sunset and perhaps give to the tank whatever heat it loses through its clear sides (you can make an insulated lid that goes on manually at/near sunset). The drawback to locating a tank on the western wall is no possible sunlight all morning long. Plus, some regions get cloud cover routinely in the afternoons.

When the sun is at the true-noon position, sunlight passes through the least amount of atmosphere, and therefore loses far less energy to the air than at dusk or dawn. The greatest levels of solar energy is obtainable a couple of hours before and after true noon, wherefore a tank on a western wall will sacrifice a couple of those hours. In some regions with predictable afternoon sunlight, the extra sun before noon will not be necessary. In the spring and fall, however, when the air is cooler and the sun's track is lower in the sky, it would be a good idea to re-locate the tank against the south wall of the home.

If ever your circulating pumps breaks down, you can use "thermosiphon" circulation...if the insulated tank is above the solar heated tank. Heated water will rise into the storage tank on its own simply because hotter water rises, and the cooler water at the bottom of the insulated tank is simultaneously forced downward to the heater tank. Excellent. But you'll need to keep the entire system filled continuously with water, meaning that it will be connected directly (i.e. no shut-off valve in between) to the well pump, and its pressure.

I should add that water having no well-pump pressure receives and gives heat more efficiently than water under higher pressure, but whether this is a significant factor in solar-heated water I do not know. As water expands when heated, water completely filling a tank/pipe will resist heat intake to some degree, but if that water is also under pressure, heat conduction is even less.

I do not believe that heat is the kinetic motion of atoms, as per the standard belief among textbook scientists. I believe that heat is a "gas" of free electrons filling the atomic spaces of any substance, and that the source of these free electrons is in the so-called "solar wind." As currents of solar electrons strike the earth, they force their way into whatever materials they strike, and the expansion of materials thereby is my definition of heat.

The reasons that modern scientists continue to trash this "caloric" theory of heat includes the harmonizing of their kinetic theory with their (insane/occult) theory of a Big Bang. That is, the power of the Big Bang caused wild (and inconceivable) sub-atomic (i.e. electron and photon) motion still with us to this day, which motion is defined as heat. If you don't believe in a Big Bang, neither do you have a basis by which to advance the kinetic theory of heat, a theory that views the entire universe in motion, and that defines the end of the universe as a heat death (when all motion ceases).

If you believe that electrons orbit atomic cores, and that they meanwhile catch and throw out photons in the process, you're as kooky as was Albert Einstein (who advanced the photon theory). It is impossible to have a satellite orbiting any body millions of times per second, and to believe that photons (otherwise called "light particles") fly about at the flesh-piercing speed of 186,000 miles per second is sheer lunacy (Einstein claimed that photons have zero mass in order to justify that speed, but a particle with zero mass is red-flag erroneous). Electrons predictably bounce and roll around the atomic core randomly/chaotically, whenever the atom is disturbed, but they do not orbit in the strict sense of the term. Each atom has countless electrons, and theorists show their idiotic sides when claiming that a relatively tiny electron has exactly the same level of electrical charge as a relatively huge proton.

The speed of light is 186,000 miles per second because light is a longitudinal wave capable of transferring that fast through a wave medium having zero inertia. Wave transfer is not the same as a particle moving through space; an electron emitted into space at a mere 1000 miles per hour may cause a wave transfer at 186,000 miles per second. The wave medium consists of weightless free electrons issued from all stars and filling the universe. Therefore, both heat substance, and the cosmic aether that Einstein trashed, are made of free electrons.

The reason that these ideas continue to be trashed is the argument of scientists that neither heat nor the aether show signs of possessing weight (which is true), whereas both are expected to have some weight if indeed they are substances. The problem is, scientists have latched on to the faulty Newtonian definition of gravity, which teaches that gravity attracts all things. That definition misleads scientists into believing that electrons have weight, even though they do not. Any particle repelled by gravity has zero weight, you see. Heat rises because gravity repels electrons, and every part of a gas/liquid having a greater density of free electrons is thereby made to rise.

Scientists believe that hotter portions of gases/liquids rise in cooler portions because hotter portions are lighter, but one can easily disprove this explanation, for there is no such thing as an atom hotter than another. Temperature is what happens to the outside of the atom i.e. the specific number of free electrons invading it to give it lift.

Scientists have never proven that electrons have weight; they have only proven that electrons have mass (which is not necessarily weight). Weight is due purely to gravitational attraction, and if gravity is a negative force, as I think it is, it is expected to repel electrons (for a negative force repels another negative force). Gravity is then defined rightly as the huge pool of heat (i.e. free electrons) in the earth's interior, which repels the captured electrons on the undersides of all atoms toward the topsides. This opens to gravity's "view" or "bite" every atom's positively-charged protonic core...wherefore gravity attracts all atoms (for negative attracts positive).

Logic tells me to eliminate as much horizontal piping (and horizontal tanks) as possible, because heat rises more than spreading out in any other direction (always insulate hot piping). If you can figure out a way to use clear tanks that stand tall, great, but as gravity-formed water pressure increases with water depth, it might not be a good idea if the clear sides are glued together with silicone. Single piece large-diameter plastic tubing wouldn't leak under pressure, but these would not be cheap. You could make your heating system a series of tall clear tubes, which would lose heat (in cloudy periods) much slower than metal tubes. Put some dark metal on the inside of the tubes.

Check out some of the many websites on solar heaters. And because our solar-heated water may not be very hot for long periods, I should share the following: "Tank temperature should be no less than 130 degrees to prevent bacterial growth, such as Legionnaires disease."
http://www.naturalhandyman.com/iip/infwaterheater/infwhadjust.shtm

If you're interested in building your own batch solar heater, the following website gives you all the information you'll need to know:
http://www.green-trust.org/2000/solar/sunontap/Default.htm