Solar Powered Air Conditioning

Solar Air ConditioningI think EVERYONE has considered how solar powered air conditioning would be a perfect solution to one of our biggest energy needs. As it gets hotter, you get more cooling! Right? Well, sort of, in reality central air conditioners use so much energy (several thousands of watts) that they would quickly overwhelm a standard residential solar panel installation even during sunny summer months.
But Professor Marcelo Izquierdo of the Universidad Carlos III of Madrid realized that there is another way we could solve our solar powered air conditioning problem. Instead of using a standard air conditioner compression system, he considered a technology that has been used by industry for many decades, absorption chilling.

Instead of powering a compressor to condense coolant through a standard air conditioning unit, absorbption chilling uses waste heat (from a turbine, hot garage, sunlight) to drive a circulatory system of cooling fluids. Here is one case where more outdoor heat would result in more indoor cooling. In addition, there could be significant energy savings as a result of the process. Also, these absorption air conditioners contain no ozone depleting coolants, while certain older central air conditioning units are still full of the stuff. (source)

Just a few considerations: How large will the thermal collectors need to be? Do they need to be roof mounted like solar panels? Is absorption chilling more efficient than simply mounting solar PV panels and using their electricity output to drive standard air conditioners?

Learn more about Absorption Cooling here, and here.

+40 to Solar Power

What if your windows could double as transparent solar panels? Free energy with your sunny view! Scientists at MIT have developed a solar concentrator in the form of a dye that can be applied to windows. The dye redirects sunlight toward the edges of the window, where solar cells pick up the energy. The obvious benefit of such a system is an unobstructed view through glass also generating solar power. Additionally, scientists claim that the dye can be applied to existing solar panels to increase efficiency significantly. (source)

PV Diagram (click to enlarge)

The dye presents a solution to certain bureaucratic barriers preventing solar energy from growing. Where I live, roof mounted solar panels are not allowed. Windows, on the other hand, are allowed. I am confident most other residential and commercial zones also permit the use of windows in buildings (hah), so I see no reason why this dye and solar cell system couldn’t be used in every building. Last time I checked, cars also had windows. Can anyone say free air conditioning? This technology will be implemented in three years, hopefully that means it will be entering the consumer market at the same time.


I often write glowingly about solar panels and how great it would be for me to control a giant laser beam. My plans for a solar powered empire work fine when the solar array is built in space, but odds are any significant solar arrays will be built first on Earth. So, after the sun goes down the power goes out! Our primary means of energy storage, what we need in order to light our nights, are chemical batteries. DeathStar

Batteries have gotten us pretty far, allowing us to carry mobile phones, laptops, flashlights, etc. But all these things work on a small scale. Sure, we have car batteries to jump start our engines, but in the end they aren’t built to do much else on a reliable basis. Chemical batteries are volatile, toxic, and have a short lifespan. They wouldn’t be able to power a solar civilization when the sun goes down, not until we see some chemical battery breakthroughs.

Till then we have the flywheel. Flywheels work like mechanical batteries, storing energy kinetically rather than chemically. They do this using a spinning wheel or disk. When energy is added to the flywheel, the wheel/disk is spun by a motor, when energy needs to be subtracted or utilized, the motor engages the spinning disk, generating electricity. A heavier disk adds a linear amount of potential energy storage. A disk capable of higher speeds, on the other hand, adds a squared amount of potential energy storage. Thus, disks meant to store a large amounts of energy must be able to spin at very high speeds (16,000 RPM, for instance). The trouble is, normal materials spinning at this speed explode due to the extreme forces acting on their surfaces. This is why modern flywheels are built using materials such as carbon fiber.Battery Container

Several companies have started making large scale flywheels, but these days the most common use for a flywheel is power regulation. A large flywheel installation can smooth out bumps in the energy grid caused when power demand and supply fall out of sync. In the worst cases, a desynced power grid will cause a brownout or blackout, shutting down power completely. Residents of New York and more commonly, California, suffer from these disturbances. Unlike a generator, a flywheel can instantly respond to dips and jumps in an energy grid, preventing a frequency shift great enough to shut down the system.

Point is, while smoothing out our grids is a great idea anyway, I think flywheels could also be used to store and generate energy overnight. They aren’t toxic, they recharge very quickly, they last for a long time, etc. Plus, they spin really really really really fast.