While many people associate renewable energy with solar and wind energy, other renewable energy sources like geothermal energy are increasingly popular. Home geothermal energy is becoming a popular energy source for heating and cooling homes.
This article will cover what is geothermal energy, how geothermal energy works, home geothermal energy for heating and cooling. We’ll also look at their pros and cons of geothermal energy to help give you a better understanding of this topic.
Home Geothermal Energy Overview
Many people may not have a personal experience with home geothermal energy. However, it is the norm in some areas. For instance, 95% of the buildings in Reykjavik, Iceland, use geothermal energy. It is among the cleanest cities ever. The Geothermal system is a sustainable and clean alternative source of energy.
It does not emit harmful gases or waste like other sources of energy like nuclear energy or the use of fossil fuels. Have you ever wondered what Geothermal energy means or how it works? Is it a viable source of energy for powering your home or business? If you have ever had such questions, read on to know all about geothermal energy.
What is Geothermal Energy?
What does geothermal energy mean, anyway? Earth comprises three main parts; the Core, mantle, and crust. The word “geothermal” is a combination of two Greek words, “Geo” and “thermal,” which means the Earth and heat, respectively. Therefore, geothermal energy is the energy that comes from the high temperatures within the Earth’s Core.
The Core is a part of the Earth containing hot and molten iron. It is double layered and about 4000 miles below the surface. Scientists and researchers estimate that the temperature at this part of the Earth hits between 5000-110000F. The heat comes from the slow and continuous decay of the radioactive materials. Thus, there is excessive heat and magma. The mantle comes into play at this point.
The mantle comprises 1800 miles of magma and rock. However, it is not a continuous layer. Instead, it is divided into other smaller parts called the plates. The plates form continents and ocean floors. According to continental drift theory, the plates constantly move at the rate of about one inch every ear.
These movements cause the continental plates to drift in towards each other or against each other, causing earthquakes. In places where the Earth’s crust has faults, thinned or fractured, hot and molten magma comes closer to the surface of the Earth. If the magma seeps into the water, it generates geothermal energy that is hot steam on the surface. That is called geothermal energy.
How Does Geothermal Energy Work?
Geothermal energy is extracted through wells drilled into reservoirs full of hot water and steam underneath the Earth’s surface. Therefore, we categorize geothermal systems as a baseload power source. It means that its power output remains consistent and reliable 24/7. Therefore, comparing it to other sources of renewable energy, it is more reliable.
The working principle of geothermal system follows traditional steam engines, where water is heated to produce steam using fossil fuels. The steam later rotated a turbine that activated a generator. However, geothermal energy uses steam directly from beneath the surface of the Earth.
Home Geothermal Heating Systems
When you talk of geothermal heat, many people think of geysers or volcanic hot springs. However, that is not the case. Geothermal heating is an efficient, low-emissions, and viable source of heat for homes. So, how does geothermal home heating work?
It works through harnessing the heat energy a few feet below the surface of the Earth. The heat energy is converted into warm air using geothermal heat pumps. Electricity powers the geothermal heat pumps in small amounts. Geothermal heating is the most efficient way to heat your home.
The surface of the Earth absorbs about 50% of the solar energy, and geothermal energy is produced from the absorbed solar energy and the radioactive decay of the minerals.
Home geothermal systems work by burying pipes full of liquid several feet beneath the surface of the Earth.
You can bury them in your yard, beneath your house, or under your driveway. The liquid inside the tubes/pipes absorbs the trapped heat energy. It then later transfers it into a geothermal heat pump. The Heat pumps remove the heat from the liquid and, similar to a furnace, it passes it to your home through the air ducts.
These geothermal heating systems require a little electricity to run and do not burn fuels. There are different setups for geothermal home heating systems,
- Closed-loop systems
It is a geothermal configuration system comprising continuous underground tubes that are full of liquid. The liquid transfers the collected geothermal system to your heat pump. You can set up the system vertically or horizontally.
A vertical system is the most famous geothermal home heating system and does not need much outdoor space. A driller is used to drill holes where a continuous piping system is installed vertically.
In a horizontal closed-loop system, pipes are installed in the yard or beneath your driveway horizontally. Rather than using a drilling rig, you can use a backhoe to install the configuration. Therefore, a horizontal design can reduce your front-end heating and cooling costs.
- Open-loop system
An open-loop system uses groundwater as a heat source. Rather than use a liquid to circulate heat into the pump, an open-loop directly pumps the groundwater into the heat pump, transferring the geothermal energy.
Home Geothermal Cooling System
As we saw above, geothermal home heating moves a temperature conducting liquid inside a loop of pipes underground near or beneath your home. But, contrary to the wording, GHPs can also cool your home. So, how can the same GHP that heats your home cool it during summer? The heat transfer process can work in reverse.
During the circulation of air in your house, the geothermal heat pumps work to separate the heat and the atmosphere. It transfers the heat into the liquid, circulating it to the ground. Because the Earth has lower temperatures, the heat from the liquid dissipates into it.
The cold air that blows into your house results from eliminating the heat from the circulating air, conducting that heat into the ground, and bringing the cool air back to your house.
All this begins when your heat pump’s compressor increases the refrigerant’s temperature and pressure. Next, the high-temperature refrigerant moves across the condenser, coming into contact and transferring the heat to the heat transfer fluid in the ground loop. The liquid then circulates through the piping in the ground, releasing the heat into the soil.
After the heat is transferred into the ground loops, the refrigerant passes through an expansion valve—both pressure and temperature of the refrigerant decrease. Now, the cold refrigerant moves through an evaporator coil, coming into contact with the hot air in your house.
The cold refrigerant absorbs the heat from the air, leaving cold air only. The basic refrigeration cycle goes on until your home has reached the desired temperature.
We can use the geothermal system in the following three fundamental ways.
- To Generate electricity
The hot water and steam beneath the Earth can be piped into geothermal power plants to produce electricity. The renewable electricity can be incorporated into the national grid or sold alone. There are many potential applications of geothermal electricity in production, lighting our homes and powering other appliances.
- Heating and cooling out homes
As we saw above, geothermal heat pumps are vital equipment that serves as heating and cooling systems in our homes. They use organic liquids to transfer heat from the ground to our homes during heating. The heat is removed from the air in our homes and moved back into the ground during cooling. Therefore, we can enjoy summers and winters or spring with the help of geothermal systems.
- Direct use
You can also use geothermal energy directly. Such use is called direct geothermal use. You can find it in natural Spas, public baths, and hot springs. Steam and hot water can be piped to homes directly where the geothermal reservoir reaches the Earth’s surface.
Geothermal energy is available 24/7. Therefore, you can be assured of a constant power supply. It is also renewable, meaning that it never runs out. In areas that rely on hot water reservoirs, the volume removed to generate geothermal power is re-injected. Therefore, geothermal energy is sustainable and efficient. Even in heating and cooling, using geothermal energy beats conventional ACs always.
It does not use electricity to pump hot air into your house or cold air out. Instead, it releases the hot or cold air into the ground during heating and cooling. A geothermal air conditioner reduces your electricity expenses by 20-50%.
The higher the Energy Efficiency Ratio of your HVAC system, the more energy you get out of it. Conventional HVAC systems have an EER of 9-15, while Geothermal ACs have an EER of 15-25.
Geothermal unit is slowly gaining popularity as an alternative source of renewable energy. In earlier days, people used it just for bathing. However, geothermal energy is used in different applications nowadays, thanks to the new technologies for harnessing home geothermal power. Currently, there are three technologies used in geothermal power plants.
Binary-cycle Power Plants
These are power plants that operate with waters having lower temperatures (225-3600F). The heat from the water boils a working fluid (a low boiling point organic compound) that vaporizes inside a heat exchanger, powering the turbine to generate electricity.
Upon the completion of the cycle, the water is re-injected beneath the surface for re-heating. Binary-cycle power plants have little to no air emission because the geothermal water and the working fluid are separate.
Flash-steam Power Plants
This geothermal power plant forms the most common types of Geothermal installations and use scalding water (over 3600F). Water pressure allows it to flow through the underground pipes and wells. When the water flows upward, it loses the pressure, turning into steam which powers the turbine. Upon completing the cycle, the leftover water and condensed steam are re-injected back into an underground reservoir.
Dry-steam Power Plants
These power plants pipe the steam directly from beneath the Earth’s surface. The upward flow of the steam through the pipes powers the turbines.
With the applications of such technologies in harnessing geothermal power, it can add enough electricity to the grid. In the future, we expect even more advanced technology in the use and harnessing of Geothermal renewable energy.
Reading through the review, you may wonder, is using geothermal power safe? Yes, geothermal energy has minimal to no risk if done right. However, there are some risks involved, just like any other industrial project. The key is extracting the renewable energy from a safe location. Our ancestors used geothermal hot springs for cleansing and warmth over the years with no reported risks.
The energy can be converted to electrical power or used as direct-use geothermal energy (when the underground hot water is used for a function directly). For example, it could be for heating pools, homes, laundry facilities, or agricultural use.
Direct-use geothermal requires low temperatures than electrical applications. However, high temperatures are necessary to turn the turbines during the generation of electricity.
The known dangers of geothermal power occur during drilling. To get higher temperatures, you must drill holes deep below the surface of the Earth. In addition, some areas are more earthquake-prone than others. Therefore, before drilling geothermal wells, you must survey the area’s seismic activity.
Costs & Tax Incentives
Installing a geothermal heating system is an expensive undertaking. From undertaking surveys, drilling, and installing the appliances, the costs can be prohibitive. However, since the power source is renewable, this is cheap in the long run. Homeowners can expect to pay $18,000 to $45,000 for home geothermal installation. Once installed, heating costs are expected to be reduced by 50% and cooling costs reduced by 35% compared to conventional heating and cooling systems.
The return on investment is guaranteed by federal and state tax incentives. Initially, the federal tax credit allowed homeowners to claim 30% of the money used to buy a geothermal heat system and install it.
Currently, the tax credits are at 26% between 2021-2022 but will decrease to 22% by 2023. Such incentives allow homeowners to buy and use geothermal equipment instead of costly fossil fuels. However, factors like the installation date, residency requirements, tax liabilities, and system criteria are considered to qualify for the tax incentive. Whether you bought the system on credit, installments, or paid upfront, you are eligible.
Also Read: Best Solar Generators 
Home Geothermal Energy Pros and Cons
Geothermal power is eco-friendly in its all use and production aspects. According to some studies, geothermal energy least affects the environment. There are no harmful gases or solid waste produced by geothermal power production or use.
- Abundant supply
Geothermal energy is a perfect escape from the problems of wind and solar energy. It exists infinitely on the Earth’s Core. Moreover, because it is reliable and intrinsically fundamental, you never worry that it will run out.
Many homeowners use geothermal energy as heating and cooling systems because of its low cost. Although the initial capital outlay is high, you can save between 20-50% by using residential geothermal power for heating.
- Small set up
Although geothermal power plants require substantial underground piping, they have a small land footprint. Therefore, you can use the land for other functions. Compared to other forms of renewable, geothermal energy’s land footprint is the smallest.
- No use of fossil fuels
Geothermal energy does not need transport o mining. The entire geothermal process occurs through water and the Earth’s heat. Hence, there will be no emissions of gases or fumes.
- It is renewable
So long as the Earth exists, the heat in its Core will remain. If the natural cycle continues, water will remain available. Conversely, fossil fuels can be depleted.
- High installation costs
The upfront cost of installing a home geothermal power system is prohibitively high. The price has always remained a setback for many homeowners. For an average house, it can cost between $10000-20000.
Geothermal energy can cause instability on the surface of the Earth. For example, in creating sizable geothermal power plants, much hydraulic fracturing may trigger earthquakes occur.
- Some concerns about the environment
Although geothermal energy is eco-friendly, some regards are there concerning water usage in large-scale power plants. Several compounds may seep into the ground during the process of production.
- Running out of steam.
If you do not take care of the steam in a geothermal power plant, it may run out, causing a meltdown.
Frequently Asked Questions (FAQs)
Can Geothermal Energy Power a House?
Yes, geothermal power can power various house needs. However, one of the best-known applications is heating and cooling. Geothermal ACs are preferred over conventional ACs because they are cost-effective. However, installing residential geothermal power can be expensive initially. You can use geothermal electricity to power your TV, refrigerator, lights, and many other applications.
How Does Geothermal Heating Save Money?
Geothermal heat pumps are energy-efficient machines. They have an EER of 15-25% compared to conventional HVAC system’s 9-15%. The higher the EER, the more energy an HVAC gives you. Thus, geothermal ACs are better. They reduce your electricity expenses by 20-50% because they do not use electricity to suck hot air into your house during heating. A geothermal heat pump is about 65% more efficient than a conventional HVAC system.
How Much Will it Cost Me to Heat My House With Geothermal Energy?
While a geothermal heating system benefits the environment, it can also save you many heating costs. However, the cost of heating your house depends on its floor size and how low the temperatures are. As we have already seen, compared to a conventional HVAC system, a geothermal heating system reduces your heating costs by up to 50%. In a month, you end up spending less than $1000.
Is Geothermal Energy Available Everywhere?
Yes, you can find geothermal energy almost everywhere. However, it is more accessible in some areas or regions compared to others. For example, if a place is rich in naturally occurring hot water reservoirs and hot springs, it will be easier to find and use geothermal energy.
How Long Do Geothermal Systems Last?
Durability is among the primary advantage of geothermal home systems. They are built to be long-lasting. For instance, indoor geothermal system components can last for over 25 years, while a ground loop may last for more than 50 decades. On the other hand, a conventional AC unit or a furnace can only last for 15 years. Since the system has few moving parts, minimal maintenance is needed.
Geothermal energy is a renewable source of energy whose potential is untapped. Compared to other renewable sources, geothermal energy has the least land footprint.
You can use it for various purposes like cooling and heating, powering electrical appliances, bathing, among other many uses. Home geothermal energy’s advantages surpass the disadvantages by far. We should embrace geothermal energy as a powerful resource to utilize.
I’ve always been a lover of Mechanics and the engineering that goes on behind it. Naturally had a knack for fixing things and i’ve had lots of adventures that generators are second nature to me.