Illustration of businesses using solar chimneys

Solar Chimneys: Clean and Cost-Effective Heating and Cooling

As we prepare for the big man in red to make his yearly appearance, his normal entryway for businesses is getting an upgrade. Solar chimneys are becoming a more common building design element to create comfortable environments inside.

What are solar chimneys?

Solar chimneys, also known as a thermosiphon or thermal chimneys, are “passive” conduits that harness environmental conditions to generate cool air within buildings and expel hot air, or vice versa. Comparably, many buildings use “active” energy consuming measures, which use complex building systems to create comfortable indoor conditions, such as boilers and chillers. 

Solar chimneys are tall structures designed to face the sun with a dark, matte surface to absorb solar radiation. They use the same principle as a fireplace, where the heat naturally rises to the top of the chimney and cool air enters the bottom. In the case of solar chimneys, the sun is what causes the air to heat up and rise. This allows cooler air from below to be pulled into the chimney, warmed and vented. The process of rising hot air and entering cool air provides ventilation in the chimney and helps cool the building below.

However, solar chimneys can also be used to heat buildings when the weather turns cool. For this, the ventilation outlet at the top of the chimney, where the hot air normally exhausts, is closed and interior vents are opened, allowing the hot air back into the building.

The keys to solar chimney design

Solar chimneys are particularly effective when they are placed in an area where they can be directly hit by sunlight. Size matters too — they need to be tall and wide, but not too deep so that the surface areas that both absorb the sun and come in contact with the air inside the chimney is maximized. Solar chimneys can vary in design for maximum efficiency, including adding multiple chambers to increase the surface area or using materials that absorb the most heat, such as a black frame, tinted glass and insulated glazing.

Another important aspect of the design is how cool air gets funneled into the solar chimney. Two methods are typically used for this ventilation process. One option is to open windows on the lowest level of the building to capture cool air flowing through the building and send it the base of the chimney. Another option is to bury a pipe underground; the air in the pipe cools and eventually makes its way to the base of the chimney where it can be heated and released. The design one chooses is up to the capabilities of the building and cost.

The benefits of solar chimneys

There are numerous advantages to using a solar chimney to regulate the air inside buildings.

  • Solar chimneys have a smaller impact on the environment compared to traditional chimneys that emit smoke. Solar chimneys simply emit air, thus no pollution and no carbon dioxide emissions.
  • Solar chimneys are a cost-effective choice for a cooling and heating system compared to air conditioning or heating units. Plus, no electricity or gas is needed to power the chimney.
  • They are more reliable and easier to maintain than conventional units since they don’t require any actual mechanics. No power outages or breakdowns affect them — only sunlight. Since they don’t require fuels to operate, they also are easier to keep clean.

As business customers consider more cost-effective and eco-friendly options to heat and cool their buildings, solar chimneys are becoming a viable choice. As their energy utility, it’s important to be aware of this trending technology to assist your customers in their decision-making. Plus, with the holidays around the corner, Santa will certainly appreciate the latest innovation in chimney technology.

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