Some 20 years ago I was first introduced to the concept of a Solar collector, not for electricity or heating but for lighting the interior of buildings. If you think about it we spend a lot of time inside buildings with lights turned on even if it’s a bright day outside. Commercial buildings consume 20–30% of their total energy consumption for indoor lighting. Imagine just how much power we could save by just using what’s outside and bringing it inside. Not to mention that sunlight is full spectrum light that humans need to be healthy and not that neon white of fluorescent tubes.
Some might wonder if what we are doing with solar panels to produce electricity and then powering LED lights is not the same. No, not even close. Solar panels have a maximal efficiency of 20% so far and we need to transport, store, transport, and use it all of which introduces loss.
Ok, so what are Solar Collectors? To distinguish them from Solar boilers, usually called solar collectors, we can use terms like Daylighting Technologies. There are three different approaches to those technologies and fall under the terms of Light Pipe, Optical Fiber, and Heliostat.
Light pipes work well over short spans and can be seamlessly incorporated into existing structures. Optical fibers, on the other hand, are better for longer distances and provide design versatility, though they demand greater upkeep. Heliostats are ideal for large spaces, but they are expensive to install and operate.
All of those technologies can be considered an advanced version of a basic skylight. They transport light from the roof to the interior where skylight is not practical or even possible. As such have the same disadvantage of being useful only if there is sunlight outside and is not cloudy but that is why they are not a primary source of light but a supplement to existing artificial lightning.
A Light Pipe is just a pipe with a highly reflective interior wall, a collector at the top, and a diffusor at the bottom.
This principle was downsized by a Liter of Light movement. By using discarded plastic bottles filled with water and bleach that act as diffusers they are lighting up the interiors of shacks in the developing world.
It’s the same principle as deck prism.
For centuries, sailing ships used deck prisms to provide a safe source of natural sunlight to illuminate areas below decks. Before electricity, light below a vessel's deck was provided by candles, oil and kerosene lamps—all dangerous aboard a wooden ship. The deck prism laid flush into the deck, the glass prism refracted and dispersed natural light into the space below from a small deck opening without weakening the planks or becoming a fire hazard. wikipedia
A more modern take on Light Pipe are Optical Fibers. They are similar to optical cables used in data transmission with the difference that optical cables for data are produced with more quality control and are thin and delicate if not properly protected with good insulation but optical fibers for transporting sunlight are much thicker, and reduce cost are not made from silica or glass but from plastic, Polymethyl methacrylate (PMMA). This approach has its benefits but also a lot of negatives one being that such installations are expensive and prone to overheating of entry points of the strands, where sunlight meets the fiber as sunlight is concentrated on a very small area things can get really hot. Just remember how you can start a fire with a magnifying glass.
One benefit of it is that it’s compact and can transport light for quite a way without a lot of loss.
Heliostats could be the oldest lighting technology. There is some evidence that it was used as far back as ancient Egypt. It consists of mirrors that bounce light to where it’s needed.
Modern versions are mostly used in solar power plants where mirrors are used to concentrate sunlight to the top of the tower.
Whereas in most of the world, those power plants are efficient and cost-effective ways to reduce CO2 emissions, in the US they are plagued with engineering and management blunders making them financially unfeasible. It’s like they don’t want them to work …
For example, Alliant Energy Completed 150 MW Solar Power Array in 2022 that has almost the same footprint as Morocco Heliostats, 1,200 acres, and has some 390,000 solar panels to produce an equivalent power to 7,400 heliostats. That’s 52 times the failure points.
Not to mention the environmental impact. More in-depth articles about toxicity and challenges of decommissioning solar panels can be found on Forbes, Wired, Environmental Progress, etc.
I’m still baffled why the US is falling so behind in nuclear energy when it’s the safest and environmentally friendly out of all “alternative” sources.
In fact, solar produces 300 times more toxic waste per unit of energy than does nuclear energy, according to Environmental Progress, a Berkeley, California, nonprofit that supports the expanded use of nuclear energy.
On a more up-to-date chart from Statista shows the US as being absent. It looks like all construction is “paused”. And the UK also lost its position as they too are floundering about.
I don’t like how the media put blinders on the populous and convinced us that solar panels are the only way forward without looking at just what goes into them and what to do with them after their productive life ends as they do have a life span of around 10-20 years.
Not all that’s shiny and new is the best approach to doing things. There are many ideas in our march to the future that were ahead of their time and not feasible with technology when they were taught off, but now when we should take another look at them those technologies are sidelined because they are considered low-tech. Similar to the technologies for harvesting water from the air using a natural phenomenon instead of power-hungry desalinization. I made a whole post about that technology. While not a complete solution it can significantly reduce power requirements.
And that’s the point. We can significantly reduce our power requirements by looking at “alternative” approaches that supplement our current way of life without detracting anything from it.
The discourse around solar energy often spotlights the advancements and adoption of solar panels, but a closer examination reveals that traditional solar collectors have enduring value. While modern photovoltaic panels are heralded as a beacon of renewable energy, solar collectors offer a time-tested, efficient method for harnessing the sun's power for both lighting and heating purposes. By redirecting and repurposing sunlight, these systems can significantly reduce dependence on artificial lighting and the associated energy costs. It's crucial to consider the full spectrum of options available to us. This means revisiting and refining older methods like solar collectors that may be overshadowed by the allure of newer technologies but still possess untapped potential. By integrating a combination of both old and new alongside solar panels and other renewables, we can create a more versatile and robust energy strategy.
https://www.mdpi.com/2071-1050/15/14/11044