Not Exactly ‘Smart Home’ But It Is Free Air Conditioning
February 27, 2022
I’m making a bit of a ‘detour’ off the usual Smart Home track this week with something I found pretty interesting. As Debbie and I are building a new home we have looked at all kinds of different options for the project. And as Texas can be a rather warm place during the summer months, the idea of free air conditioning intrigued me.
Don’t get me wrong, I’m referring to the monthly cost of air conditioning which can make homeowners crazy during a hot Texas summer. There are obviously up-front costs, just like traditional air conditioning solutions. It’s the operating costs that are free with a solar chimney. This is a system that can effectively cool your house, especially if you live in a dry climate.
So how does something called a ‘solar chimney’ actually cool your home? A solar chimney utilizes the physics of warm air rising. The “chimney” is a vertical shaft that rises above the roof, similar to a fireplace chimney. The sunny side of the shaft is glass. The inside of the shaft is painted a dark color. When the sun shines into the shaft, it hits the dark interior surfaces and warms the air in the shaft. The warm air then rises and is allowed to vent out near the top of the chimney through operable vents.
The rising air creates a “convective current.” As the warm air rises, other air must move in to replace it. The rising air literally sucks in the replacement air. At the bottom of the shaft is another vent that allows the air in the house to become that replacement air. The house air enters the shaft and replaces the rising air that is venting out the top of the shaft. The house air then must be replaced. This could happen by opening windows around the house. An internal breeze is created and the house cools naturally without electricity usage.
On very hot days, the outside air may be too hot to create a sufficient cooling effect. To make this system even more effective, and to truly provide free air conditioning, an underground piping system can be installed to conduct outside air into the house as the replacement air for the exhausted house air. With the windows kept closed, air is drawn in through the only available opening, the underground piping system. The intake for this air is located on the cooler, shady side of the house. The air travels through underground pipes and is cooled by the earth. Because of the earth’s cooling effect, when the air enters the house, it is cooler than the outdoor air.
This kind of system creates a convective flow of air. That’s what the action of rising hot air and falling cool air is called. The air flows without any mechanical fan and the air is cooled without any air conditioning compressor. A solar chimney is all natural and uses no electricity — your house is air conditioned for free.
I don’t know exactly how much this could ultimately save on air conditioning, especially in Texas. But being able to leverage a solar chimney during the warming months of spring and the cooling months of fall may save significant costs in annual air conditioning. And as our home will face east (shady side) it will be oriented perfectly for putting the solar chimney on the back (sunny side) where it won’t affect the aesthetics or view of the house from the street. And ideally positioned for the sun in the heat of the day. I do see some definite advantages using a solar chimney in conjunction with traditional air conditioning and a smart thermostat however.
Perhaps a solar chimney is a better solution to consider further up north, like for my family and friends in Massachusetts, New Hampshire, Michigan, Wisconsin or Minnesota. Perhaps something for them to consider if they decide to build a new home or renovate the one they’re in. I could see this as a very cost effective option for friends with cottages on Cape Cod, especially where the square footage is generally less than their primary homes.
Whether Debbie and I decide to design a solar chimney into our home design has yet to be decided but it is a competing solution. It would certainly fit with other sustainability options we’re considering like solar power, home battery arrays and managing home electrical usage.
What are you doing around sustainability in your home? Have you deployed a solar power system at your home? What about solutions around preserving water? Or simply more efficient windows, insulation or automation to reduce energy consumption? There are dozens of options to choose from depending on preference, platform or budget.
We love hearing your feedback on our posts and would especially like to hear from you on this little departure from the norm. Let us know in the comments, DMs and email as always. Also, don’t forget to Like and Follow Smart Home On The Range on the social channels. Until next week …
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