Sure, it’s easy to use the sun to heat your home, but what about your cooling needs? If you go off the grid with solar power, does that mean that you have to give up AC entirely? Well, the answer is: not necessarily. Solar air conditioning is an advancing technology with some very exciting developments on the horizon.
When you think about it, it actually makes a lot of sense to use solar power to cool your home: solar harvest potential is high when the sun is shining bright, and that’s also when you want to run your central air conditioner on full blast. In fact, midday—the hottest part of the day, when AC usage is highest—is one of the most productive times for solar energy. And since The Department of Energy reports that air conditioning accounts for roughly 11 billion dollars of the US’s annual electricity spending, getting this appliance to be more efficient is of high importance!
Thankfully, some forward-thinking companies are on the case. There are a couple of different options for sale—some that are even pretty easy to take with you from room to room.
What Are Portable AC Units?
The issue in the past with solar air conditioning has been that solar panels are not yet powerful enough on their own to generate the kind of power that your typical AC unit requires to cool a whole house. Enter portable units. The idea is that instead of working to cool your entire home, you carry the unit with you as you move from room to room. This is much more efficient, since the smaller the area that needs to be cooled, the less power used.
Portable Solar Options
Greencore has been developing a grid-tied unit to address the problem of AC inefficiencies. Their portable air conditioner has a 170-watt solar panel that works during the day to power the unit. Then at night, or on cloudy days, it can be plugged into the wall à la your typical AC unit and powered from the grid. It tops out at about 10,200 BTUs—enough to cool about 600 square feet. It’s obviously not a perfect solution since it still relies on some carbon-based power, but the grid tie-in makes it more consistent than previous prototypes. The company claims that both McDonalds and the US Navy have been working with them to test and develop units for their operations.
We have also heard rumors that a company called Rotartica has developed an AC unit which essentially refrigerates sun-heated water in solar tubes. However, when we looked, we were unable to locate an up-to-date product page for this device.
Lastly, there are a bevy of purported solar air conditioning units coming out of Hong Kong and China, but we haven’t been able to find any reliable data on them beyond the specs listed on the sales pages. So buyer beware!
If you simply must have a clean, efficient solar cooling unit right now, you may want to think about investing in an evaporative cooler. These systems work using the same scientific process as perspiration—that is, they rely on the cooling power of evaporation to lower the temperature. Then, a large blower pushes the cool air around the room. The California Energy Commission reports that they can lower the temperature by as much as 30 degrees! Evaporative coolers are energy-efficient enough to run if you already have solar power in your home, and we’ve heard reports that there may be a portable solar-powered model on the market from Coolerado. You can even DIY your own, if you feel like taking on a project. There are plenty of tutorials available online.
DC Air Conditioning Units
Another high-efficiency option is to purchase a DC-compressor operated, solar-powered AC window unit. Kingtec Solar’s models contain an AC/DC converter that is completely sun-powered during the day, and stores excess power into a battery unit to power the device at night. The company claims that this set-up can keep your system running without pulling any power off the grid. The only drawbacks are the price—at roughly $2,000, these units are a real investment—and they weigh in around 200 pounds, which is pretty heavy (and definitely not portable!). Still, with an output of 16,000 BTUs, you won’t be standing in front of the AC sweating and trying to cool off using a few pathetic puffs of air.
The Future of Solar AC
As solar technology continues to develop, there may not even be a need to rely on portable solutions, and instead opt for whole-house systems. In 2014, SolarCity, one of the largest solar panel producers around, announced that they would be teaming with Carrier, a popular HVAC corporation, to address the problem of providing efficient, affordable, solar-powered climate control. These two heavy hitters also intend to offer a $1,000 rebate to customers purchasing their equipment through Carrier and servicing it through SolarCity. They anticipate that this offer will spur massive growth, so soon, portable units may be largely a thing of the past.