SoLar compression, or [How to compare the effectiveness of solar designs.]

Solar heat generating systems, come in all shapes and sizes and to compare one design to any other seems almost like an impossible task.

There are no standards, no benchmark tests and no guidelines to follow. The reviews are vague and often depend on some individual testing. Customer satisfaction merely expressed by a number of stars.

But which design is really effective, under what conditions and why?

What is the magic number?

On a geometrical level, the answer is surprisingly simple;

Asun [m2] / Vheat [l] = SoLcom [unite less]

But what does that mean?

Imagine a square glass window of exactly 1 square meter, sitting like a lid on top of a shallow black box with exactly the same internal size. Imagine then, that this window is perfectly facing the sun and let’s 1 square meter of sunlight go through, hitting the inside of the box and heating the air-volume within.

If this box then is only 1cm deep, the volume of air it contains, is exactly 10 litre.

1m2 / 10l = 0.1 SoLar compression.

1_to1 01

Every solar heat generating system consists of the same two main elements.

  • the collector, gathering as much sun-light as possible and
  • the receptor, which converts the collected energy into heat

Collectors being measured as an area, whilst receptors are always described as a heated volume.

It is clear then, that the effectiveness of any solar heat generating system is largely defined by the relationship of those two.

The more sun-shine collecting area is available to any system and the smaller the volume of the receptor converting the sunshine into usable heat, the higher is the efficiency of the entire system.

This relationship is the unit less factor of the SoLar compression [SoLcom] and can be calculated by dividing the active sunshine Area [Asun in m2] by the heated receptor Volume [Vheat in litre].

Asun [m2] / Vheat [l] = SoLcom [unite less]

This factor can be calculated for any SoLar heat generating system and is completely power independent.

It does not use the SoLar input-power of a system, nor does it describe the quality of any thermal insulation. It simply defines, the geometrical relationship of the active SoLar area to a specific heated volume.

simplified linear systems

In the next instalment SoLenium technology will discuss the practical implications of the SoLar compression factor, as well as discuss it’s specific advantages and uses.

So, if you want to learn more about how to take advantage of calculating the SoLar factor of any SoLar oven or other SoLar heat generating system, stay tuned!