Do the wheels on the bus go round and round?

Ignorance is a thing that wastes everyone’s time. I learnt of a solar panel company that exclusively used Genersys solar panels that were asked by the Advertising Standards Authority to prove that the solar panels that they use “worked in cloudy conditions”.  To a layman this might at first sound reasonable enough, but to anyone in the thermal solar industry it is a bit like proving that the wheels on the bus go round and round. I shall explain.

The Advertising Standards Authority is a body set up to ensure (amongst other things) that advertising is truthful in the United Kingdom. As a result it can require advertisers to prove the truth of advertising claims. Obviously certainly claims made by advertisers such as “because you’re worth it” are beyond proof. Other “claims” such as the fact that Genersys solar panels work on cloudy days are statements of scientific fact. It seems that the good folks at the Advertising Standards Authority are short of a basic knowledge of science.

Genersys solar panels, like other solar panels whether thermal (producing heat) or photovoltaic (producing electricity) are designed to exploit radiation. Light is a form of energy. heat is a form of energy. Solar panels convert light energy into heat energy.

The sun is roughly ninety three million miles away from the earth and most of that distance is a vacuum. Heat cannot travel through a vacuum (well most heat cannot). When the sun shines on the earth it does not direct a beam of heat through 93 million miles of space to heat up a specific solar panel. It beams radiation through space in the form of light.

When light reaches the atmosphere it diffuses. Direct sunshine on the surface of the earth is never ever direct, however apparently so. The sunshine is simply radiation that that is less diffuse in cloudless weather and more diffuse in cloudy weather.

So when on cloudy days light strikes the surface of a solar panel it strikes (in the case of Genersys solar panels) a surface underneath the glazing called “an absorber” so called because the surface is designed to absorb light. Absorber surfaces are scientifically “blackbodies” usually coloured black or very dark blue so that it may absorb light rather than heat.

They are dark so that they will absorb as much light as possible. They are in the case of Genersys panels also “selectively coated (microscopic ridges) so that there are as much surface area exposed to light as possible. They are not designed to absorb heat – all substances absorb heat to some extent, although the absorption of heat depends mainly on the substance. The ability to absorb light depends more on the colour of the substance – white reflects light back into the atmosphere and black absorbs heat.

Now when light (whether from a cloudy day or from so called direct sunshine) strikes the absorber surface it causes the molecules in that surface to vibrate. When molecules vibrate they rub against each other. When things rub against each other they vibrate and that friction creates heat in effect turning light back into heat. This happens whether the weather is fine  or cloudy. In cloudy weather there is less light – less insolation – so it takes a bit longer to collect light energy than it would on a day without clouds.

These processes are exactly the same as those that burn your skin on cloudy days. You should always where sun cream to protect your skin if you are out “in the sun” even on cloudy days. Mothers have known this for years, covering their delicate skin of babies to protect it from being burnt by light, even on cloudy days.

You will see that I have provided the scientific explanation, rather than the “proof of the claim” that the Advertising Standards Authority require. In order to do that it would be necessary for the ASA to study some elementary physics. I suggest that they do this. They do not have to have an education in physics to a high level to understand the proof, but some things universally accepted as obvious for centuries should not be asked to be proved by solar companies. The request reflects badly on the ASA.

Now if the ASA asks advertisers to “prove” climate change they will find a large body of scientific opinion (a large but not a majority of it) that disputes that climate change is man made. What then?

One Response

  1. […] Click here to read the full post VN:F [1.1.5_471]please wait…Rating: 0.0/5 (0 votes cast)SHARETHIS.addEntry({ title: "Solar Panels & Cloudy Days", url: "" });Related PostsSolar Panel Installation Faqs- How Many Panels?Solar Installation FAQs- Roof LoadSolar Panel Payback in MarylandInvesting In Solar EnergyIf you enjoyed this post, make sure you subscribe to my RSS feed! Tags: cloudy days, common solar questions, solar panel question, solar panels, solar thermal, solar thermal industry […]

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