La geothermal energy It is one of the most important and least known sources of renewable energy. This technology takes advantage of the heat stored under the Earth's surface to produce heating, cooling and domestic hot water (DHW) in homes, industries and other buildings. In this article we will delve into how it works, its advantages, disadvantages and comparisons with other technologies such as aerothermal energy.
How does geothermal energy work?
La geothermal energy It is based on the Earth's ability to store the heat produced within it. Using geothermal heat pumps, it is possible to extract this heat and use it to heating in winter, cooling in summer and providing hot water for sanitary useThe process is based on a closed circuit in which a fluid (a mixture of water and glycol) circulates through pipes buried underground.
In winter, this fluid absorbs heat from the subsoil, which is at a constant temperature, and transfers it to the building. In summer, the process is reversed: the heat inside the building is transferred to the subsoil, naturally cooling the room. This system is highly efficient, as it uses less electricity than traditional heating and air conditioning systems.
This type of energy is inexhaustible and is available the 365 days a year, 24 hours of the day. One of the great advantages over other renewable energies such as solar or wind, is that its performance is not dependent on weather conditions (sun, wind, rain, etc.). Geothermal energy is stable and continuous.
Geothermal energy applications
Geothermal energy currently has some key applications, both in the residential and industrial fields. Let's take a look at them below.
- Indirect heating and cooling: As we have mentioned before, geothermal heat pumps provide heating in winter and cooling in summer, with an installation that can be adapted to underfloor heating or fan coil systems.
- Electricity production: In certain parts of the world where geothermal resources are high temperature (more than 150 ºC), it is possible to generate electricity using steam turbines.
- Industrial and agricultural facilities: In industries such as agriculture, geothermal energy can be used to heat large warehouses or greenhouses, increasing agricultural yields in colder climates.
Types of geothermal resources
Geothermal resources are divided into three broad categories according to their temperature.
- High temperature (over 150 ºC): They are generally associated with volcanic phenomena or areas of tectonic activity. In these cases, thermal energy can be used to generate electricity.
- Average temperature (between 90ºC and 150ºC): These resources are not sufficient to generate electricity, but they can be used for heating and some industrial processes.
- Low temperature (less than 90 ºC): These are the most widespread and can supply homes and buildings with heating, cooling and DHW.
Advantages of geothermal energy
Geothermal energy has numerous advantages over other energy sources. Below we detail the most important ones:
- Consistent performance: It does not depend on weather conditions and its production is stable throughout the year.
- High efficiency: Geothermal heat pumps offer very high performance, with a coefficient of performance (COP) greater than 4, meaning that for every kilowatt of electrical energy consumed, more than 4 kilowatts of thermal energy are produced.
- Less environmental impact: It does not emit toxic gases or polluting particles. As it does not use fossil fuels, it does not contribute to the greenhouse effect.
Disadvantages of geothermal energy
Although geothermal energy has many advantages, there are some drawbacks that should be considered before installing such a system.
- High initial investment: The installation of geothermal systems requires a considerable investment compared to traditional heating or air conditioning systems. However, this cost is amortized in the long term due to their high efficiency.
- Requires space: Facilities often require a significant amount of land to bury the geothermal circuit pipes.
- Not viable in all locations: There are places where geothermal resources are not sufficiently accessible, which limits their implementation.
Geothermal Heat Pump (BCG)
One of the best-known applications of geothermal energy is the geothermal heat pump, also called BCG. The main features of this system are the following:
High efficiency: Geothermal Heat Pumps are highly efficient because they work with a heat source (the subsoil) whose temperature is constant throughout the year, avoiding meteorological fluctuations.
Stability: Heat pumps are connected to heat exchangers that remain stable in temperature throughout the year, ensuring constant performance.
These pumps not only provide heating in winter and cooling in summer, but are also the ideal choice for preheat sanitary water, contributing to combined energy savings.
Heating and Cooling with the same system?
One of the strengths of both geothermal and aerothermal energy is their ability to combine heating and cooling in a single system. During the winter, the system transfers heat from the subsoil to the building, while in the summer, the system expels heat from the house to the subsoil.
In addition, this type of installation can also be used to heat places such as pools, which significantly increases its attractiveness for owners of single-family homes or large complexes.
Comparison of geothermal energy with other renewable energy sources
An important aspect when choosing geothermal energy is to compare it with other renewable energy sources. Let's do that below.
- Geothermal vs. Solar Energy: The main advantage of geothermal energy over solar energy is that its performance does not depend on the number of hours of sunlight. While solar energy can be intermittent, geothermal energy offers constant performance throughout the year.
- Geothermal vs. Aerothermal: Aerothermal energy is another emerging technology that works in a similar way to geothermal energy, but instead of using heat from underground, it uses heat from the outside air. The main difference is that the efficiency of aerothermal systems can be affected by extreme outside temperatures, which is not the case with geothermal energy.
- Geothermal vs. Biomass: Biomass is a renewable energy source based on the combustion of organic waste. Unlike geothermal energy, biomass does produce emissions and is not always as efficient. However, it can be a viable alternative in places where access to geothermal resources is limited.
Conclusion
Geothermal energy is one of the most promising renewable energy systems. Although the initial investment can be high, its stable performance, high efficiency and clean energy source are factors that make geothermal a preferred option for those looking for renewable energy systems with minimal impact on the environment throughout the year.
Furthermore, its ability to combine heating and cooling in a single system makes it a complete and sustainable solution for home and industry.