How to Build a Geothermal Heat Exchange for a Solar Chimney

  • 40-60 hours
  • Advanced
  • 5,000-25,000
What You'll Need
Plastic or metal pipes
Thermal pipe connections
Ground drilling machine
Heat pump
Water or non-toxic refrigerants

Over the last few years, the use of a solar chimney has been increasing in popularity due to the growing concern about global warming and pollution. The solar chimney is just one of many environmentally-friendly ways to keep the house warm during the winter months.

Aside from being pollution-free, a solar chimney can also significantly cut down the heating expenses of a household. But did you know that solar chimney can also generate heat from the high underground temperature of the earth? The solar collector at the bottom of the tower traps the rising hot air from the ground creating a greenhouse effect. Energy is generated as the hot air rises rapidly to the top of the chimney by using turbines. This energy, in turn, is used to heat the house.

This process is called geothermal heat exchange which is an excellent cost-effective way in cooling and heating a house or building. This process is also environmentally-friendly because it has almost zero emission. Another great thing about geothermal exchange is its availability. You don’t have to go to other places to search for it; the heat is just under your feet. Moreover, the earth’s temperature is always constant and the heat energy is relatively shallow. But how will you able to build a geothermal heat exchange for your solar chimney?

Step 1 – Drill a Series of Wells

Geothermal heat exchange systems involve drilling holes in the ground. A drilling machine is usually used in order to drill deeper to the ground. The holes should be up to 200 feet deep and large enough for two plastic or metal pipes measuring 3 inches in diameter. Insert the pipes.

Step 2 – Connect 2 Pipes at the Bottom of the Well

At the bottom of the well is a U-bend where the two pipes are connected in sequence. In order to bond the pipes very strong, make sure to use thermal pipe connections. Keep in mind that these pipes will be kept underground for many years. The pipes’ durability depends on how well they are connected together underground. The two pipes work as the ‘in’ and ‘out’ pipes where the heat exchange takes place.

Step 3 – Pressure Test the Pipes

Before filling the pipes with water or refrigerants, make sure to pressure test them first. Use sand to fill the ditch around the pipes. This is a great way to protect the pipes from being damaged by sharp debris or rocks.

Step 4 – Use a Geothermal Heat Pump

Connect the pipes in the well to the solar chimney using a geothermal heat pump. The pump works by exchanging the air inside the house using the heat generated from the ground. Follow the specific manufacturer instructions on the heat pump that you purchase.

Step 5 – Turn on the Geothermal Heat Pump

Start the geothermal heat exchange by turning on the pump. It is relatively easier to pull air using long tubes compared to pushing it using a fan. The solar chimney can use rising warm air from underground. During this process, a vacuum is created to generate heat from the pipes. Keep in mind though that drilling and installing wells alone can cost thousands of dollars. So make sure that you have consulted with professionals and are financially ready before beginning the project.