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What Local Solar Applications?

A high precision solar concentrator will provide a focal point of intense heat. The next step is to use this heat to power something.

Clearly, the same basic criteria of simplicity, local construction and maintenance, and open source, that we applied to solar concentrators must apply to basic applications. However, beyond these criteria we can add:


Higher efficiency was mentioned as an added bonus of solar concentration. This is because energy efficiency is always proportional to some form of energy gradient. With heat the greater the difference between the “heat source” and the “heat sink”, the more efficient anything in between can run, be it roasting grains or running a steam engine.

However, for application design, striving for greater and greater efficiency may be unproductive. Chasing marginal gains in efficiency may make sense with fossil fuels, since the fuel costs money and so small increases in efficiency pay for themselves over time, but with solar energy the fuel is free, so at some point simply increasing the size of the collector is more effective than increasing efficiencies. For instance, in most situations having the ability to boil water, cook, bake pottery, produce steam, run a small steam engine, would be better than having only one complex application.

The mathematics here is wrong. For instance, a 10 percent increase in efficiency for fossil fuels is significant, and indeed most fossil fuel applications are close to their theoretical efficiency maximum. For solar concentrators on the other hand, in many situations it’s easier to simply increase the surface area of light capture by 10 percent the add more complications to the design.

Furthermore, in most situations all the solar energy potential will not be used, so it is better to have a diverse set of functional applications rather than a single efficient application – since many things can be done on location with solar energy, the energy lost to inefficiencies in a “crude” design is often much less than the energy it would take to transport the material to a centralized processor and back.

Easy to dismount

Since many applications can be mounted on a concentrator, each application should be easy to dismount, and when possible share as many of the same components as possible. So for oven applications, an oven can be built so that the interior can be removed and replaced with another interior for another task. For steam applications, turning a valve can send the steam from one application to another.

Application development strategy

Though all the applications in the following chapters are possible to build now, clearly some are easier to build than others. So it makes sense to first try to develop what is easier, and the experience gained in the process will help developing the next application.

So the series of applications described in the following chapters are presented in an order intended to create a domino effect of development.

A single individual developing, refining, using or demonstrating a single application can have a significant impact in both developing new ideas and techniques as well as in inspiring others to build and development.


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