A Thermosphoning Collector System

Enlarge Image Image Gallery [1] Set your compass for the width of the 2 X 4 (about 3-1/2"") and scribe an arc that goes from one corner of the board to the edge. [2] Trim the wood along the line with a saber (or coping) saw. [3] Mark off the 1/2""holes on 5-7/8""centers. [4] Press a groove into the fins (this photo shows the copper version). [5J The aluminum plates are sandwiched around the tubes and stapled. (6] A completed absorber plate assembly is ready for glazing. [7] Hinges allow us to adjust our collectors for sun angle. [8] Cold water enters at the bottom right, while solarheated fluid exits from the top left side of the mounted collector array.

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

If the modern solar water heater seems too costly and complex, give some thought to . . .

In our technologically advanced country, it's all too easy to get in the habit of assuming that complicated solutions to problems are more thorough and, therefore, somehow superior to simpler approaches. Take the usual attempts to capture energy from the sun, for example: A typical commercial solar domestic hot water system hasIf the modern solar water heater seems too costly and complex, give some thouaht to . . . as a minimumIf the modern solar water heater seems too costly and complex, give some thouaht to . . . a pump, several collectors, a maze of plumbing, numerous temperature probes, and a differential thermostat.

But, you may well wonder, are all those components really necessary? Well, as we recently found out, it's entirely possible to build an effective solar water heater that doesn't require a single watt of electricity to get its liquid from one place to another.

WHAT GOES UP MUST COME DOWN

MOM's water-heating setup circulates through the courtesy of an everyday physical phenomenon: Heated fluids rise because their lower density (in comparison to the same substances when they're cooler) reduces the influence of the force of gravity per unit of volume. Hence, circulation occurs when cold water in the system falls from the storage tank (which sits about two feet above the top of the collectors) . . . at the same time, water inside the suncatchers is heated and tends to rise . .. back toward the storage tank. The imbalance in densities (and therefore in gravitational attraction) forms a complete convective loop.

Because the "pump" of the thermosiphon setup is the heat of the sun itself, the intensity of that radiation regulates the volume of flow through the pipes. In fact, when the sun stops shining on the collectors, the system is effectively shut off.

However, though the concept of thermosiphoning is elegantly simple, there are a few basic rules to follow when designing such a collector.

RSS | Comments | E-mail | Print