Light/Heat Battery

What if you could take the energy from the solar panels and turn it into light/heat and then store it. And then "shine" the light onto a "solar panel" at night to make electricity at night aka 24/7

10KW Solar Panel (40KWHr/day) @ $7,000
12kW Sol-Ark Controller/Inverter/Charger @ $7,000
40KWHr Battery (Light/Heat Battery) @ $$$
10KW TPV Solar Panel to extract energy 24/7 (41% efficency aka 16KWHr) @ $$$$$

Info on TPV Solar Panels
New TPV Solar Panels with 41% efficiency from MIT

If the system is cheap enough fine but being 20% or more less efficient than most of the competing systems comes with a penalty.  May be okay for small scale systems but burning iron, ammonia or running hydrogen thru a fuel cell are all in excess of 60% efficient.  The other major point this misses is 50% to 70% of the energy used in a normal home is heat based.  So it would be stupid to convert it from heat to electric and back to heat for most small scale systems.  Instead directly use it as heat with no conversion needed.

It's an interesting idea. The proposals I see are for grid-scale or heavy industrial applications. I have also read that this might be combined with standard solar PV panels to capture and convert a broader spectrum of light. I don't know that the technology is mature enough for homestead use, but it's worth watching.

Best domestic use case is to use thermal solar panels and store the heat in water to use for showering and/or central heating.
For an industrial scale they use molten salt as a thermal storage and spin a steam turbine 24/7.

Dominique Bouchier wrote:Best domestic use case is to use thermal solar panels and store the heat in water to use for showering and/or central heating.
For an industrial scale they use molten salt as a thermal storage and spin a steam turbine 24/7.

This setup is actually solid state with no moving parts, and to extra the heat they use a "special solar panel" at night that can turn light/heat into electricity with a 41% efficicency. The solar battrty is hotter than molten salt its at 2400C/4352F.

It would have to be extremely hot.  Solar panels don't use all the wavelengths of light equally.  They make most of their power in the blue wavelengths, which in general, has more energy than the red wavelengths.  The "heat battery" would need to get up to 4000+ degrees F to shine the wavelengths of light that solar panels utilize.  So imagine having something as hot as a welding arc in the middle of your home?

Michael Qulek wrote:It would have to be extremely hot.  Solar panels don't use all the wavelengths of light equally.  They make most of their power in the blue wavelengths, which in general, has more energy than the red wavelengths.  The "heat battery" would need to get up to 4000+ degrees F to shine the wavelengths of light that solar panels utilize.  So imagine having something as hot as a welding arc in the middle of your home?

Solar panels are tuneable by adjusting how they are doped to run on other frequencies of light.  It is a matter of panel design.

C. Letellier wrote:

Michael Qulek wrote:It would have to be extremely hot.  Solar panels don't use all the wavelengths of light equally.  They make most of their power in the blue wavelengths, which in general, has more energy than the red wavelengths.  The "heat battery" would need to get up to 4000+ degrees F to shine the wavelengths of light that solar panels utilize.  So imagine having something as hot as a welding arc in the middle of your home?

Solar panels are tuneable by adjusting how they are doped to run on other frequencies of light.  It is a matter of panel design.

That's right, the technology we're talking about is thermo photo voltaics, designed specifically to utilize light in the infrared frequency range. If this can be commercialized, there is an enormous amount of waste heat that could be converted to electricity, potentially with a much greater efficiency than the technology like thermo electric generation that we use now.

This is interesting but if this is for you I'd have to ask how much power do you really need? The average single family detached home uses about 40kwh of energy per day, the bulk of which goes to heat and AC. I think if you make some other energy efficient changes like heating yourself not the room, using fans, etc, then the 10kw solar system might be fine for most people's needs.

I think for scoring this system from a permaculture perspective I give it (1 is bad, 10 is best):
Self reliance factor: 1 the temperatures and equipment involved seem very complicated so only large entities could operate it
Complexity factor: 2 not as complicated as nuclear but still a lot of components
Pollution factor: 5 the materials seem exotic and with the high temperature may break often (fact check me on this)
Cost factor: 3 extra equipment seems expensive and expensive to maintain and keep safe
Versatility factor: 10 it does involve electricity and heat so pretty versatile energy currency