Investigate solar heating, find out the why what and how…

Solar heating collectors come in many different types and categories, but one can usually narrow them down to just three: Flat Plate, Vacuum Tube, and Concentrators. Just for fun, I’ll throw in one more - a coiled-up Black Garden Hose. Yap, even the lowly garden hose can be considered a solar collector.

While a coiled Garden-Hose lying in the sun may be an amusing way to fill a small wading pool, a Batch Collector can provide enough hot water for evening showers. However, the Flat-Plate Collector whether it be open or closed loop is perfect for domestic and commercial needs.

A Vacuum Tube Collector will perform even when there’s snow on the ground, while a Reflector Concentrator will process the sun’s heat to provide enough steam to turbines to generate power by the megawatt.

While only three basic types exist, there are many many collector sub-categories. Unfortunately, this leads to some confusion. For example, let’s check out why most of us fail to recognize the differences between a solar collector and a panel. So what, why make a fuss about such insignificant differences.

Why, because if you intend to get past filling a wading pool to the real McCoy, you’ll need to know. Question, is it important to do something really worthwhile, improve your home; reduce your power bills saving money? If the answer is yes-yes-yes, then you need to know.

So okay, just exactly what is a solar panel and just exactly what is a solar collector, how do they work and what do they look like?

Glad you asked, sometimes the terms do get confusing. The term used correctly, a solar panel usually describes a rectangular array containing multiple solar-voltaic cells connected together to generate electricity. On the other hand, a novice may refer to a single photovoltaic cell as a solar collector. Well, they do collect sunlight.

Usually, a collector is a solar heating devise that collects and transfers thermal energy to water or air. The first generates electricity, and the second produces heat.

Okay, let’s take a look at what happens when solar heating begins its work on a Solar Collector. As you know, solar energy immediately begins the process of transferring heat into any surface it touches.

That’s somewhat interesting, because the sun’s light must travel such a long-long way to get here. One might think some of its energy would be lost on such a long trip. But no, it’s still got the juice, and solar hot water systems are one spin-off.

I’m sure you savor its arrival, most everyone does. In fact, most wallow in its rays, especially on those long sunny days. Remember those summer drives, how you enjoyed the warm yet cooling breeze through the open windows; tunes playing and everything was fine. Comfortable, you rested a bare arm out the window. But suddenly – ouch, hot – solar heating.

If you whence, even slightly when you think about the sting, you have a basic understanding of what solar thermal energy can do to the fluid in a collector.

I know you know that a person can make fire by rubbing two sticks together - right, not that I’ve done it, but I know it can be done. Anyway, the reason why fire is possible is because the constant rubbing get the wood hot.

You see, rubbing perturbs the molecules in the wood. Pretty soon, they become very very agitated and begin to bang into each other. The rubbin’ really miffs em. As it continues, they get more and more irritated, until they’re down right irate. The temperature of the wood surrounding them rises. This continues until they burst into flame. A fire!

One more example and we’ll get on with it. Think about solar heating, a hot summer day on a sandy beach. You know how hot it can get on your bare feet. Did you ever notice, the lighter its color, the cooler it was. That’s because lighter colored surfaces reflect light, e.g. snow.

Sometimes they move slowly (low frequency), and sometimes fast (high frequency). Well, light’s kind-a like an ocean wave. The only difference is that there are whole bunches of different waves (frequencies) moving together. The big difference is the frequency. Sunlight is really a bunch of ultra-ultra high frequencies, all coming at us at the same time, hence solar heating.

Think of it this way, we can see a myriad of colors in a city at night, but only white light coming from the sun. Up close, the colors are clearly discernible, get further back, they begin to blend, go way waa-y back and all’s you can see is white light.

Did you ever see a video of our planet from the space shuttle? Of course, you have. Okay, did you notice the blaze of light from heavily populated areas on the dark side? Now think, could you see any color – no, but there’s million of em, you just couldn’t see them. Why, because white is a combination of all the (frequencies) colors.

Next time you see a rainbow, remember all the colors came from white light. The same colors you saw through a prism in your school’s science class. Raindrops are nature’s natural prism that separate sunlight into the various colors just as the small ones did at school.

Remember learning about the visible spectrum, and about what you can’t see. That part of the spectrum where UV’s and X-rays reside. Remember learning how the upper atmosphere filters out (99%) of them. The point is: there’s lots of different frequencies in sunlight.

Okay, now let’s go back to stick-rubbing. Suppose you speed up the process (frequency); if you can keep it up, combustion will take place sooner. As you can see, faster rubbing (frequency) generates heat – hummm somethin like solar heating.

What about a solar collector, well if you pointed a radio stations signal at it, would anything happen; no, because its frequency is too low. Wait a minute; the radio signal is still a whole bunch higher than stick rubbing. So why didn’t it do something?

Good question, maybe this will help. Put a glass of cold water in a microwave and a few minutes later, you’ve got hot water. Microwave is a much higher frequency than a radio signal and is therefore more efficient at heating.

Now consider sunlight. Its frequencies are a quantum leap beyond microwave oven frequencies. For example, when sunlight falls on a solar collector’s surface - solar heating results, the same as rubbing two sticks together, except everything is happening faster. The collector's absorbent material begins to absorb heat, which in turn transfers the heat to the water. And not an ounce of electricity.

The absorbent material inside the collector’s box is usually some kind of black heat absorbing material. Sunlight striking this material drives its molecules absolutely bonkers. And the solar heating process begins.

A glazed glass lid covers the box facing the sun. This glass contains the stray waves that would otherwise escape out of the box. Cold liquid of some kind circulates into, through and out of the collector’s pipes as hot water.

The same energy that burns bare feet, is the same energy that solar hot water systems use.

Solar collectors convert solar thermal energy into a useable source of heat to generate hot air, water and mass with varying degrees of efficiency, 55 to 60% being the highest.

The systems collector type will determine the degree of solar heating efficiency. Improvements in glazing technology continue daily, the major reason being the rising cost of crude oil, coal and natural gas.

Okay, with the workings of the suns energy out of the way, let’s look at the two solar collector system classes:

1. Passive Solar Systems
2. Active Solar Systems

Passive Solar Systems
A passive solar system converts the sun’s energy into a useful source of heat, without the assistance of mechanical or electrical equipment. It depends entirely on gravity and heated water’s tendency to circulate on its own. The converted energy, heats water, heats thermo-mass, causes air movement. Basically, passive solar systems use the sun’s energy as is.

Active Solar Systems
Just like the passive system, active solar also converts the sun’s energy into a useful source of heat. However, from there on this class uses mechanical and electrical devices to enhance the heating and circulation of heated air or liquids.

There you have it, a brief glimpse on how solar heating works. A system will reward you with genuine $$ savings. Even an inexpensive batch system will provide enough hot water for household needs while reducing energy costs. I would certainly recommend investigating solar energy further, you’ll be glad you did.

Custom Search