We know that geothermy is the heat of the Earth, and the term “geothermal” is often associated with volcanoes and geysers. In Russia, geothermal energy is mainly used on an industrial scale, for example, there are Far Eastern power plants operating on the basis of the heat of our planet.
Many believe that to do geothermal heating at home with your own hands is something from the realm of fantasy. Is not it? But this is absolutely not the case! With the development of modern technology, domestic use of “green energy” has become quite real.
We will talk about the principles of operation of alternative heating, its advantages and disadvantages, comparable to traditional heating systems. You will also learn about how to arrange the heat exchanger and how to install geothermal heating with your own hands.
The content of the article:
- Some historical facts
- The real advantages and disadvantages
- About geothermal heating sources
- The principle of operation of such heating
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Two types of heat exchanger location
- Option 1. Vertical placement of the external collector
- Option # 2. Horizontal location of the soil collector
- Immersion horizontal heat exchanger in the reservoir
- Do it yourself: what and how
- Costs and prospects for payback
- Conclusions and useful video on the topic
Some historical facts
When the oil crisis broke out in the 70s of the past century, a burning need arose in the West alternative energy sources. It was at this time that the first geothermal heating systems began to be created.
Today they are widespread in the United States, in Canada and in Western European states.
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The use of the energy of the earth's interior has a weighty advantage: the resources used are obtained free of charge and spontaneously recovered
The internal block of the geothermal system takes up little space, looks like familiar household appliances
The initial investment in the device of the system using geothermal energy is higher than the installation of the boiler, but the minimum funds for maintenance and operation justify and quickly pay for the project
The equipment that processes the energy of the earth into heat, does not emit combustion products, does not permanently burn firewood, coal, peat, gas
Prospects for geothermal heating
Dimensions of the geothermal system indoor unit
The cost of installing and operating a heat pump
Environmental priorities of heat pumps
For example, in Sweden, the Baltic Sea water is actively used, the temperature of which is + 4 ° С. In Germany, the introduction of geothermal heating systems is even sponsored at the state level.
At the mention of geothermal energy sources, we always imagine a valley of geysers or volcanoes, but the sources we need are much closer. And they will help us warm up in the winter and cool in the summer.
Pauzhetskaya, Verkhne-Mutnovskaya, Okeanskaya and other geothermal power plants operate in Russia. But there are very few facts of using the energy of the Earth in our private sector.
The real advantages and disadvantages
If in Russia geothermal heating of the private sector is relatively rare, does this mean that the idea is not worth the cost of implementing it? Maybe this issue should not be addressed? It turned out that it is not.
The use of a geothermal heating system for a home is a cost-effective solution. And there are several reasons for this. Among them is the quick installation of equipment that can work for a long time without any interruptions.
If you use in the heating system not water, but high-quality antifreeze, it will not freeze and its wear will be minimal.
We list the other advantages of this type of heating.
- The procedure for burning fuel is excluded. We create an absolutely fireproof system, which, in the course of its operation, will not be able to cause any damage to housing. In addition, a number of other issues related to the presence of fuel are excluded: now there is no need to look for a place to store it, to be engaged in its preparation or delivery.
- Substantial economic benefits. During the operation of the system will not require any additional investments. The annual heating is provided by the forces of nature, which we do not buy. Of course, in the operation of a heat pump, electrical energy is expended, but at the same time the volume of energy produced significantly exceeds consumption.
- Ecological factor. Geothermal heating of a private country house is an environmentally friendly solution. The absence of the combustion process eliminates the release of combustion products into the atmosphere. If many are aware of this, and such a heating system will receive due ubiquitous distribution, the negative influence of people on nature will decrease many times.
- Compact system. You do not have to organize in your house a separate boiler room. All that will be needed is a heat pump that can be placed, for example, in the basement. The most volumetric contour of the system will be located underground or under water; you will not see it on the surface of your site.
- Multifunctional. The system can work both for heating in the cold season, and for cooling during the summer heat. That is, in fact, it will replace you not only a heater, but also an air conditioner.
- Acoustic comfort. The heat pump runs almost silently.
The choice of a geothermal heating system is economically beneficial, despite the fact that you have to spend money on the purchase and installation of equipment.
By the way, as a disadvantage of the system, it is the costs that will have to be mentioned in order to install the system and prepare it for operation. It will be necessary to buy the pump itself and some materials, to perform work on the installation of the external collector and internal circuit.
It’s no secret that resources are becoming more expensive from year to year, so an autonomous heating system that can pay off in a few years will always be economically beneficial for its owner.
However, these costs pay off in just the first few years of operation. The subsequent use of a collector laid in the ground or submerged in water saves considerable resources.
In addition, the installation process itself is not so complicated as to invite third-party specialists for its implementation. If you do not drill, then everything else can be done independently.
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The internal unit of the system that uses the heat of the earth, includes directly the heat pump itself, a water heater separately installed or built into the pump, and a buffer tank
Thermal energy of rocks and groundwater is enough for the organization of heating and hot water supply of a country house.
Despite the real benefits of operating heat pumps, heating the house using a gas boiler while cheaper, but geothermal energy is still used, for example, to heat water in the pool
However, in non-gasified areas, places where electricity is not supplied, the heat pump with the energy extraction of soils and water can become an aggregate providing hot water supply and heating systems.
It is reasonable to use free energy of underground water and rocks in providing warmth to household buildings, greenhouses, sports complexes
Heat pumps with energy intake from the bowels of the earth can serve as additional sources of energy needed in case of power outages
In the case of the transition of a house completely to geothermal heating, it is often necessary to construct several circuits, for maintenance of certain rings, for example, for radiator heating and underfloor heating it is better to use two heat pumps, and for Hot water third
Geothermal heating devices are perfectly combined with both traditional options and other types of alternative sources: solar panels, wind turbines and other
Indoor unit geothermal heating system
Geothermal sources in the heating of a private house
Ground-water heat pump for heating pool water
Geothermal systems in the arrangement of suburban buildings
The device of geothermal heating in the greenhouse
Heat pump as an addition to the main heating circuit
Multi-circuit geothermal system in a private house
Geothermal heating paired with solar panels
It should be noted that some craftsmen, in an effort to save learned how to collect geothermal own heat pump.
About geothermal heating sources
For geothermal heating, you can use the following sources of terrestrial thermal energy:
- high temperature;
- low temperature.
High-temperature sources include, for example, thermal springs. You can use them, but their scope is limited to the actual location of such sources.
If in Iceland this type of energy is actively used, in Russia the thermal waters are far from populated areas. They are maximally concentrated in Kamchatka, where underground water is used as a coolant and supplied to the DHW system.
For the effective use of heat energy of the earth does not need a volcano. It is enough to use those resources that are only 200 meters from the earth's surface.
But for the use of low-temperature sources, we have all the necessary prerequisites. For this purpose, suitable surrounding air masses, land or water.
To extract the necessary energy using a heat pump. With its help, the process of converting the ambient temperature into heat energy not only of heating, but also of hot water supply of a private household is carried out.
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Geothermal energy sources include underground natural objects: soils and water.
A salt solution circulates along the contour, which takes the heat of the soil. When a liquid is compressed by a compressor, its temperature rises, which is used in the preparation of the coolant for heating systems
In a similar way, the thermal energy of the water of natural reservoirs, into which the external collector of the heat pump sinks, is taken.
When taking groundwater heat from a geothermal well, the heat exchanger loops into the well and plunges through a pipeline to an indoor unit compressor.
Intake of free heat groundwater and rocks
External heat exchanger of the earth-water system
Outdoor heat exchanger in a natural pond
Geothermal heat pump well
The principle of operation of such heating
If you are familiar with how it works air conditioning or fridge, the similarity of these processes with the principle of functioning of geothermal heating is obvious. The basis of the system is a heat pump, which is included in two circuits - external and internal.
To organize a traditional heating system in any house, you must install pipes in it. to transport the coolant, and radiators, when heated, which heat will flow into premises. In our case, pipes and radiators are also needed. They form the internal contour of the system. The scheme can be added warm floor.
The outer contour looks much larger than the inner one, although its dimensions can be estimated only during the planning and installation period. During operation, it is invisible, because it is underground or under water. Normal water or ethylene glycol-based antifreeze circulates inside this circuit, which is much more preferable.
The geothermal heating system includes two circuits - internal and external, as well as the heart of the heating system - a heat pump, which, compressing the coolant, increases its temperature (+)
Thus, the heat pump is the key element that animates the entire system. If in your house there is an ordinary washing machine, then you should know: this pump will take approximately the same area.
To work, he needs electricity, but, consuming only 1 kW, it provides 4-5 kW of heat. And this is not a miracle, since the source of “additional” energy is known - it is the environment.
Two types of heat exchanger location
There are two options for heating a private house using low-temperature energy elements of the environment. The basis of the system in all three cases is a geothermal pump.
The internal circuit remains unchanged for any heating method, and the main difference is in the location of the external circuit.
Geothermal heating happens with a heat exchanger located:
- vertically - are located in wells that reveal or do not reveal the aquifer;
- horizontally - heat exchangers of systems are laid in a pit or open water in the form of a kind of coil.
Each of the types of heating given here is characterized by its features, disadvantages and advantages.
If you intend to create such a heating system with your own hands, you will be interested to learn more about each type.
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The choice of the method of placing the external collector depends on the availability of free space near the manor house
The horizontal arrangement of the external collector of the geothermal heating system for a small house will require the decommissioning of only 36 m²
In the case of a device for heat supply of a house ranging from 300 to 600 m², a plot of 110 m² will have to be removed from use.
For the construction of a horizontal version of the collector, located in the ground, you will need from 200 to 500 m² of free space
In order to reduce the size of areas withdrawn from use because of the device collectors, different methods are used, for example, partial laying in a trench along the boundaries of the site or roads
A variety of options are used to group underground pipes. One of them - the installation of hinges in the form of baskets
When choosing a pipe laying scheme for the external part of the heat pump, it should be remembered that the working part of the system should be buried below the level of seasonal soil freezing
A good combination of horizontally laid pipes and vertical wells will help reduce the size of the decommissioned site.
Vertical collector placement
Group of vertical loops collector heat pump
External heat pump collector for large house
Horizontal heat sink pump ground-to-water
Laying the collector of the outdoor unit in the trench
Installing the heat exchanger as a basket group
Laying the pipeline along the walls and bottom of the pit
The termination of the area offset wells
Option 1. Vertical placement of the external collector
This type of heating is based on an interesting natural phenomenon: at a depth of 50-100 m and more from its surface, the earth has the same and constant temperature of 10-12 ° С all year round.
To be able to use this energy of the earth, it is necessary drill vertical wells. The technology is almost the same as preparing a water intake source.
In order to maximize the preservation of the landscape, it is possible to drill several pipes from the same starting point, but from different angles.
The external circuit of the system will be mounted directly in these wells. This will effectively take away the heat from the earth. Of course, this method can hardly be called simple and low-budget.
To create a vertical geothermal heating system you need to use drilling equipment. wells, without the use of a drilling rig solution of problems on the device system will be quite time-consuming (+)
It is relevant in the case when the territory adjacent to the house is already equipped, and the violation of its landscape is impractical. The depth of drilling can reach from 50 to 200 meters.
The specific parameters of the well depend on the geological situation at the site and the parameters of the future structure. The service life of this design is approximately 100 years.
To construct a vertical version of the system with a heat exchanger that extracts the energy of groundwater, it will be necessary to drill two water-bearing wells.
One of them, called a debit one, uses a pump to draw water, which, after heat transfer, is drained into the second, receiving outlet.
Minus geothermal system with two wells in the lack of efficiency for heating a country house. Too much energy is spent circulating the pump. But for the supply of coolant to the contour of a warm floor, the received heat energy is quite enough.
Option # 2. Horizontal location of the soil collector
To lay the outer contour with a horizontal view of heating, you need to know how deep the land in your area is frozen.
The pipes are laid below the level of freezing in the previously prepared trenches, capturing a fairly large space: to heat the house, whose area is 200-250 square meters. m, you need to use about 600 square meters. m heat exchanger. That is six acres.
The disadvantage of this design is the large area that it occupies. If you need a lawn covered with grass and flowers on the plot, this is your option. And it is better to keep the collector pipes away from fruit-bearing trees (+)
It is clear that under such conditions, the volume of earthworks will be significant. In addition, you need to consider in terms of the location of trees and other vegetation on the site, so as not to freeze them. For example, you can not have a collector pipe closer than one and a half meters from the trees.
This method of installation is used, as a rule, in cases where the site is only being developed for construction. All calculations and plans for the construction of the cottage, the organization of its heating and the planning of the land plot are best performed simultaneously.
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Stage 1: The ground-water heat pump device with a horizontal collector begins with the development of a pit or trench and laying a collector that collects heat from the soil layers
Stage 2: The collector hinges are connected to the pipes, one of which collects the brine that absorbs heat from the ground, the second returns it after the energy is transferred to the heat pump
Stage 3: Having entered the heat pump, the brine gives off energy that enters the storage water heater, which prepares the heat carrier for heating circuits
Step 4: After connecting and assembling the network, its operation is tested. When positive results are obtained, the foundation pit is filled with soil and the area above it is settled.
Laying the heat collector in the pit
Connection of a collector to pipes of an exit and an entrance to the house
Connection to a storage water heater
Site arrangement with external collector
Immersion horizontal heat exchanger in the reservoir
This method requires a special arrangement of home ownership - at a distance of about 100 m from a reservoir that has sufficient depth. In addition, the specified reservoir should not freeze to the very bottom, where the external contour of the system will be located. And for this area of the reservoir can not be less than 200 square meters. m
This option of placing a heat exchanger is considered the least expensive, but such an arrangement of homeownership is still not common. In addition, there may be difficulties if the water body belongs to public facilities.
An obvious advantage of this method is the absence of mandatory labor-intensive earthworks, although you still have to tinker with the underwater location of the collector. And special permission to carry out such work is also needed.
However, a geothermal plant that uses water energy is still the most economical.
Do it yourself: what and how
If you install geothermal heating yourself, then it is better to buy the external circuit as a finished product. Of course, we consider only the methods of horizontal arrangement of the external heat exchanger: under the surface of the soil or under water.
It is much more difficult to assemble a downhole vertical collector yourself if you do not have the equipment and drilling skills.
The heat pump is not very large equipment. In your house, it does not take much space. Indeed, in size it is comparable, for example, with a conventional solid fuel boiler. Connect the inner contour of your house to it - the task is simple.
In fact, everything is done in the same way as in the organization and heating wiring using traditional heat sources. The main difficulty is the arrangement of the external contour.
This arrangement of the house relative to the pond is more common. The main thing that the reservoir was no more than 100 meters from the cottage
The best option would be to use the reservoir, if it exists at a distance of no more than 100 m. It is necessary that its area exceeds 200 square meters m, and depth - 3 m (average freezing parameter). If this reservoir does not belong to you, then the problem may be obtaining permission to use it.
If the reservoir is a pond that you own, then the matter is simplified. Water from the pond can be temporarily pumped out. Then work on its bottom can be done easily: it will be necessary to lay the pipes in a spiral, securing them in this position.
Excavation work will be needed only for digging the trench, which will be needed to connect the external circuit to the heat pump.
After doing all the work, the pond can be refilled with water. In the coming years, one hundred external heat exchanger should work properly and not cause trouble to its owner.
If you have a land plot at your disposal, on which you only have to build housing and grow a garden, it makes sense to plan a horizontal heat exchanger of the soil type.
To do this, a preliminary calculation of the area of the future collector should be made, based on the parameters already indicated above: 250-300 square meters. m collector per 100 square meters. m heated area of the house.
If you got a plot without buildings and vegetation that you would like to preserve, the ground at the construction of an external horizontal soil contour can simply be removed: it is easier than digging trench
The trenches in which the pipes of the contour are to be laid must be excavated below the level of soil freezing.
And even better - just remove the soil to the depth of its freezing, lay the pipe, and then return the soil in place. The work is time consuming, difficult, but with a great desire and determination, you can do it.
Costs and prospects for payback
The cost of equipment and its installation during the construction of geothermal heating depends on the capacity of the unit and the manufacturer.
Each manufacturer chooses, guided by their own thoughts and information about the reputation and reliability of a particular brand. But the power depends on the area of the room to be serviced.
This figure briefly reflects the essence of the benefits derived from the use of a geothermal heating system. It is this ratio of incoming and outgoing energy that allows the system to quickly pay off first, and then save its owner’s money (+)
If we take into account exactly the power, the cost of heat pumps varies in the following ranges:
- at 4-5 kW - 3000-7000 conventional units;
- on 5-10 kW - 4000-8000 conventional units;
- 10-15 kW - 5000-10000 conventional units.
If we add to this amount the costs that are needed to perform the installation work (20-40%), then we will get an amount that for many will seem completely unrealistic.
But all these costs will pay off for quite reasonable terms. In the future, you will have to pay only minor expenses for the electricity needed to operate the pump. And it's all!
Due to the lack of efficiency of geothermal systems for heating residential buildings, they are used in as a supplement to the main heating networks or they are being constructed in complex with two or more heat exchangers
As practice shows, geothermal heating is especially beneficial for houses with a total heated area of 150 square meters. For five to eight years, all the costs of equipping heating systems in these houses are fully paid off.
If geothermal heating is not particularly in demand among the owners of private houses, then the effectiveness of the gel systems has already been estimated by residents of the southern regions. Technology solar heating facilities simple enough, and its cost-effectiveness and practicality confirmed by many years of experience in the use of Western countries and our compatriots.
Additional information on alternative energy sources is provided in this article.
Conclusions and useful video on the topic
If it's easier for you to take visual information, then this video will allow you to see with your own eyes how It is the geothermal system that functions, and also to learn more about who and why this type of heating profitable.
We invite you to watch a short video in which the owner of a horizontal subsoil collector tells about his impressions of its operation. In addition, after watching this video, you will learn about the ongoing costs associated with the operation of a geothermal heating system.
Each owner of a private house chooses himself whether to buy the services of resource-supplying organizations for him or rely only on himself. However, he is guided by a list of considerations.
The goal we set for ourselves is not to push you to a ready-made conclusion, but to share information about the solutions to the task you are facing.
Is there anything to supplement, or have questions on the subject of geothermal heating of a private house? You can leave comments on the publication. The form for communication is in the lower block.
