1. Evaporation
The fluid flowing through the loop circuit system reaches the evaporator of the heat pump, which contains refrigerant liquid. As the fluid in the loop circuit is warmer than the refrigerant, a heat exchange takes place between them. The refrigerant is heated and changes from a liquid to a gaseous state. The loop circuit fluid and the heat pump fluid do not mix at any time. The heat exchange occurs by contact between the two circuits through a plate heat exchanger.
What is geothermal energy?
Geothermal energy is the clean and 100% renewable energy that lies beneath our feet.
Geothermal
Geothermal energy is one of the most reliable and predictable renewable energies.
It is available under our feet 24 hours a day, 365 days a year.
Whether during a cold snap in winter or a heat wave in summer, the subsoil remains at a constant temperature all year round (15-18ºC/ 59-64ºF). This subsoil temperature is higher than the outside temperature in winter and lower than the outside temperature in summer.
With a geothermal air conditioning system, we will be able to make use of this energy to obtain heating, cooling, and hot water throughout the year.
All of this with hardly any consumption, since at least 80% of this energy is FREE and RENEWABLE.
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Basic components of a geothermal air-conditioning system
Types of Ground Loops
- Closed vertical loop system
- Open loop system
- Closed horizontal loop system
It consists of one or more boreholes in which plastic pipes (probes) are inserted at a depth of between 80-150 meters (262-492ft). Fluid circulates through these probes, capturing the energy accumulated underground and transferring it to the heat pump. This is the most widely used option. It requires little space, is not limited to providing heat or cold and its legalization is quick and easy.
It requires an aquifer, river, or lake to extract the water that provides the necessary energy to the loop circuit. Although it is the most efficient system use is not very common. The main reason is that the necessary resources are not usually available. In addition, legalization can be very slow and complex.
It consists of plastic pipes buried throughout the ground at a depth of 1.5-3 meters. It requires free land equivalent to 2-2.5 times the surface of the house. It is the most economical type, but the one with the lowest performance since it is affected by external climatic conditions. In addition, it is not recommended for installations that require refrigeration.
Geothermal heat pump
The geothermal heat pump requires a loop circuit system to extract the energy stored in the ground.
The heat pump manages to transform the energy accumulated in the subsoil into useful energy for your home. To do so, it only needs a small electrical consumption.
How does a geothermal heat pump work?
Geothermal operation
The heat pump manages to harness the stable temperature of the subsoil and transforms it into useful energy for the house.
With very low consumption, it provides heating in winter, cooling in summer, and hot water all year round, even for swimming pools.
- Heating, DHW and swimming pool
- Active cooling
- Passive cooling
During the winter season, the heat from the ground is used and transferred to the house.
The probes capture heat from the subsoil through the fluid circulating inside them and transfer it to the heat pump.
The heat pump uses this energy with minimal electrical consumption. It reaches the necessary temperature to heat the house, produce domestic hot water, and even heat the swimming pool.
In addition to providing heat in winter, geothermal energy can also be used in reverse, which means cooling the house during warm days.
When operating in cooling mode, the heat pump reverses its operation. It captures heat from the house and exchanges it with the loop circuit. To do so, it only needs a small power consumption of the compressor.
In this case, the pipe circuit is the cold source since it is at a lower temperature than the house, which in this case is, therefore, the hot source.
This way, it is possible to cool the house to a comfortable temperature.
One of the advantages of geothermal energy, compared to other heat pumps, is the possibility of cooling your home for free, through what is known as free passive cooling or free cooling.
Passive cooling consists of a direct temperature exchange between the loop circuit and the emission circuit of your house.
In summer, the temperature of the subsoil is lower than the temperature of the house. When this temperature exchange takes place between the two circuits, we manage to “transfer the cold” from the subsoil to our underfloor heating or fan coil installation. This way, the house’s indoor temperature is reduced by about 2-3ºC (36-37ºF). The heat pump is kept off, so there is no consumption.
This option is especially useful in temperate climate zones, where cooling needs are not very high, as well as in very well-insulated homes.
Advantages of geothermal energy
The heat pump needs a small electrical consumption to air-condition a house. If we produce this energy with photovoltaic panels, consumption will be almost zero.
As no combustion is required, it demands very little maintenance. That saves the associated costs to this service.
Heat pumps are equipment designed to operate from 20 to 25 years while maintaining their efficiency.
The heat pump will provide you with heating in winter, cooling in summer, and hot water all year round. You don’t need anything else.
Geothermal energy allows you to cool the environment of your home completely free of charge. No heat pump consumption.
Investing in a renewable energy system will increase the value of your home.
Using the free energy available in the environment will give you energy self-sufficiency. You will hardly depend on an external supply.
A house is usually our home for many years. Our planet is going to be our home for a lifetime. This is a good system for both your economy and the planet.
Geothermal energy is always available. You will have the energy you need whenever you need it, 24 hours a day, 7 days a week.
There are different grants and subsidies for geothermal energy: for its installation, property tax rebates, or tax deductions.
We can help you if you find yourself in any of the following situations:
New home?
You are building or have planned to build your home. You would like to enjoy a comfortable temperature in summer and winter without having to worry about the energy bill. You are looking for the best solution for today and the future.
Energy improvement?
You want to renew your old heating system. You are looking to reduce energy costs without sacrificing comfort. You are willing to invest in a more modern system, as long as this investment is amortized with the savings generated.
Are you an architect?
We can help you with your project at no cost to you. We will look for the best solution for your client. Once we have it, our engineering department will provide you with the calculations, design, and justification of the project.
How much does geothermal energy cost?
Knowing how much a geothermal heating and air conditioning system costs is very important if you are considering installing this system in your home.
There is a lot of information about geothermal energy, but little is said about the different factors that determine the price of the complete system.
Regarding the heat pump, there is a great variety of brands and models. The prices between one and another are very different. Sometimes it is difficult to understand the reason for this price difference.
In addition, we must take into account other elements of the installation that represent between 55% and 75% of the total price of the installation.
This lack of information can confuse you if you are considering installing geothermal energy in your home.
Geothermal price guide
To help you understand the price of geothermal energy for a single-family house, we have created this simple guide.
There are three types of loop systems: closed vertical loop, open vertical loop, and closed horizontal loop.
Out of the three options, the closed vertical loop is by far the most common, although it is also the most expensive one as well.
The cost of the loop circuit is conditioned by different factors, such as the area in which the installation is carried out and the type of soil. However, the average price of drilling is around 40€ per linear meter. This price includes the probes.
House size: 100m² (1.076ft²)
- Heat pump power: 5kW
- Drilling meters: 1 well x 75m (246ft)
- Price: 3.300€.
House size: 150m² (1.615ft²)
- Heat pump power: 7,5kW
- Drilling meters: 1 well x 110m (361ft)
- Price: 4.750€
House size: 200m² (2.153ft²)
- Heat pump power: 10kW
- Drilling meters: 1 well x 150m (493ft)
- Price: 6.300€
House size: 250m² (2691ft²)
- Heat pump power: 12,5kW
- Drilling meters: 2 wells x 90m (295ft)
- Price: 7.740€
House size: 300m² (3.230ft²)
- Heat pump power: 15kW
- Drilling meters: 2 wells x 115m (377ft)
- Price: 9.660€.
*Indicative data taking as a reference a new house and a plot with a thermal extraction capacity of around 50/60W per linear meter and a COP of the heat pump of 5.
To implement a geothermal boreholes system, it is necessary to have a permit from the competent regulatory body in each region.
Each permit application requires the submission of a unique project.
The cost of the drafting, presentation, and fees of the project for a single-family house can vary between 400€ and 600€.
The heat pump is the main component of a geothermal installation and is usually the most expensive one.
The prices of a heat pump depend primarily on its brand, power, and performance.
One of the factors that most affects the price of the heat pump is the size of the house, which together with the climate zone, determines the required power of the heat pump.
House size: 100m² (1076ft²)
- Heat pump power: 5kW
- Price: 6.000€ – 9.000€.
House size: 150m² (1615ft²)
- Pump power: 7,5kW
- Price: 8.000€ – 12.000€.
House size: 200m² (2153ft²)
- Heat pump power: 10kW
- Price: 8.000€ – 12.000€.
House size: 250m² (2691ft²)
- Heat pump power: 12,5kW
- Price: 10.000€ – 18.000€.
House size: 300m² (3230ft²)
- Heat pump power: 15kW
- Price: 10.000€ – 18.000€.
In a geothermal installation, in addition to the loop circuit and the heat pump, there are several necessary components.
One of them is the DHW storage tank, which is an essential element in any home. The price of a DHW storage tank depends mainly on the storage volume, as well as the type of storage tank and the materials used.
To determine the volume of DHW storage in a house, we calculate a need of between 40-50 litres per person.
Price of the DHW storage tank depending on the number of people and model
Number of people: up to 4
- DHW volume: 200l
- Price: 1.150€.
Number of people: 5-10
- DHW volume: 300l
- Price: 1.450€.
Number of people: 10-20
- DHW volume: 500l
- Price: 1.850€.
Number of people: more than 20
- DHW volume: 700l
- Price: 2.500€.
Geothermal installations, in addition to a DHW storage tank, usually have a buffer storage tank.
The use of this type of storage tank serves to optimize the operation of the heat pump compressor by reducing the number of starts and stops. This has an impact on consumption and, above all, on the service life of the heat pump.
Power 5kW
- Heat pump with inverter compressor: 100l
- Price: 650€.
- Heat pump with on-off compressor: 200l
- Price: 780€.
Power 7,5kW
- Heat pump with inverter compressor: 100l
- Price: 650€.
- Heat pump with on-off compressor: 200l
- Price: 1.150€.
Power 10kW
- Heat pump with inverter compressor: 100l
- Price: 650€.
- Heat pump with on-off compressor: 200l
- Price: 1.485€.
Power 12,5kW
- Heat pump with inverter compressor: 100l
- Price: 780€.
- Heat pump with on-off compressor: 200l
- Price: 1.485€.
Power 15kW
- Heat pump with inverter compressor: 100l
- Price: 780€.
- Heat pump with on-off compressor: 200l
- Price: 2.165€
Normally, the installation work for an average-sized single-family house requires 2 professionals for about 6-7 days (including drilling work).
This would mean an approximate cost of between 2.000€ and 2.500€.
Here you can find out more about the subsidies that are currently in force in our country for the installation of geothermal energy:
- Subsidies for self-consumption, storage, and thermal systems with renewable energies (RD 477/2021).
These grants approved by the government in June 2021 subsidize the installation of geothermal energy for air conditioning and/or domestic hot water in homes.
The eligible amount for closed-loop geothermal installations is 2,250€/kW installed up to a maximum per house of 13,500€.
These subsidies will be valid until December 31, 2023, but as has been the case in recent calls, the subsidies are non-competitive, that is, they will be processed in order of entry into the registry and until the credit is exhausted. Therefore, it is important to submit the grant application as soon as possible.
The starting dates for submitting applications vary depending on the regions.
These are the regionsthat have already announced their dates:
- Region of Murcia: November 3, 2021.
- Community of Andalusia: December 2, 2021.
- Community of Castilla y León: January 17, 2021.
- Community of Valencia: October 29, 2021.
- Basque Country: November 11, 2021.
- Community of Galicia: December 15, 2021.
- Balearic Islands: September 20, 2021.
- Community of Madrid: November 16, 2021.
- Community of the Canary Islands: October 29, 2021.
- Aragón: December 13, 2021.
- Cataluña: december 2, 2021.
- Principado de Asturias: January 2, 2022.
- Castilla la Mancha: December 22, 2021.
- Navarra: November 10, 2021.
- Extremadura: January 26, 2022.
Aside from the subsidies, which will reduce your initial investment considerably, you will also be able to claim tax deductions and property tax bonuses (up to 50% depending on the municipality where you live).
Energanova will inform you about all these aids and if you wish we will process them for you free of charge.
Do you want to calculate the price of geothermal energy for your home yourself?
We have developed the first calculator that allows you to estimate the investment and savings of your project.