Basics Of Geothermal Electricity Production
The Earth is an amazing place. It is constantly moving, rotating on its axis and it is filled with water and other fluids that flow in a complex system of convection currents. The Earth’s internal temperature varies from the center to the surface. The core has a temperature around 11 million degrees Fahrenheit, while the surface can reach as low as minus 60 degrees Celsius (minus 76 degrees Farenheit) at some locations.
Steam is used in maaküte(geothermal heating) plants to create electricity. The hot water reservoirs that produce the steam can be found several miles or more below the surface of the earth. Steam causes a turbine to spin, which ignites a generator and generates electricity. Dry steam, flash steam, and binary cycle geothermal power plants are the three different types.
Geothermal energy takes advantage of this natural phenomenon. Geothermal heat pumps use hot water or steam extracted from the Earth’s interior and circulate it through a closed loop system for heating homes and businesses. In the process, they convert the heat into electricity. That electricity can then be used to power your home’s electrical appliances and save you money on energy bills.
In addition to saving you money, geothermal heat pumps are healthier for your home than traditional fossil fuel-powered heating systems. Unlike most central heating units, they require no outside air to burn gas or oil. Instead, they are powered by the Earth’s internal heat source and produce very little pollution. This means fewer harmful emissions into our environment. You also won’t have to worry about an oil leak or a gas explosion destroying your house.
There are two main types of geothermal technology: direct geothermal and ground source. Direct geothermal utilizes heat stored deep within the Earth’s crust to heat buildings at the surface. Ground source technologies like a shallow well system use the heat generated by underground aquifers to keep buildings warm.
So what exactly does it take to make a geothermal heat pump? Let’s find out.
Direct Geothermal Technology
When it comes to geothermal technology, there are two major options: direct and indirect. Both types of systems utilize wells drilled into the Earth’s crust to extract thermal energy and are similar when it comes to installation. A few differences include how much water must be pumped into the system, and where the unit will be installed.
A direct geothermal system requires a minimum amount of water. This is because the water must travel through pipes inside the Earth and pick up enough heat to transfer it to the building. Water travels quickly through the pipes, so if the pipes aren’t long enough, the system will not work properly.
Indirect geothermal systems do not require as much water and are therefore more affordable. They are more complicated to install, however. Here are the steps involved:
- Dig a hole that will go down 30 feet below the frost line. The depth should be based on local weather conditions, but 30 feet is typically sufficient to reach the Earth’s interior. If the site is too rocky, add a layer of gravel to help prevent soil from eroding during construction.
- Locate three holes spaced evenly apart and dig each one to a depth of 20 feet. The holes should be spaced 10 feet apart.
- Create a horizontal tunnel between the holes using steel rods.
- Use a pipe to connect the tops of the three holes.
- Pour sand into the bottom of the holes until the pipes fit snugly inside.
- Insert thermocouples to measure temperatures at all three levels.
- Install a valve at the top of the horizontal pipes to control the amount of water flowing through the system.
- Connect the pipes to the valve and fill the holes with water. This will create a closed loop system that circulates the water through the pipes.
- Once the water is pumping through the pipes, it picks up the heat from the Earth’s interior and transfers it back to the building.
If you’re interested in learning more about direct geothermal heat pumps, check out these tips to learn what you need to know before installing one.
Ground Source Heat Pumps
Unlike direct geothermal systems, geothermal heat pumps don’t have to drill a single well to provide heat. Instead, they use the same technology found in ground source heat pumps. These systems capture the heat generated by the earth itself and deliver it to buildings. There are several different ways to accomplish this. Here are four examples of ground source heat pumps:
- Shallow Well Systems
Shallow wells are dug into the ground and lined with plastic to trap groundwater. As the groundwater heats up, it rises up through the well. When it hits the surface, it becomes heated.
- Deep Wells
Deep wells are deeper than shallow wells and typically consist of multiple layers of metal piping. The lower piping collects groundwater while the upper piping collects the heated groundwater.
- Deep Aquifer Heating Systems
Some geothermal experts believe that the best way to tap into the Earth’s internal heat is through deep aquifers. These systems take advantage of naturally occurring mineral deposits that lie beneath the Earth’s surface.
- Underground Loop Systems
Underground loop systems are similar to shallow wells in that they collect groundwater and send it through a series of tubes to gather heat. However, instead of having open ends, they terminate in a sealed chamber where the heated water is circulated. This prevents any groundwater from entering the chambers and contaminating the unit.
While both direct and indirect systems are effective at producing heat, geothermal heat pumps are far superior to traditional fossil fuel-powered heating units. Not only are they safer, cheaper and cleaner, but they also save households hundreds of dollars every year. With proper maintenance, geothermal heat pumps last 15 to 20 years and pay for themselves in less time than that.
If you’re curious about geothermal heat pumps, try our guide to choosing the right model. And if you want to learn more about the benefits of renewable energy, check out our article explaining why solar panels are better than coal plants.
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