Many property owners believe that geothermal heating at home is almost a concept from the world of science fiction and is relevant only for those regions where there are hot springs and high volcanic activity. But such natural phenomena are a real rarity, so the prospects for using this alternative energy in our conditions look very foggy. But you can familiarize yourself with the technology for creating such a system and see if it suits you.
Clarification of the situation
In fact, a geothermal pump for heating is able to generate heat even at low temperatures, so in a temperate climate it can be used efficiently. The principle of operation of the described heating can be compared with the principle of operation of a refrigerator or air conditioner. One of the main elements is a heat pump, which is included in two circuits. Internal is a traditional heating system of radiators and pipes. The external circuit is a heat exchanger that is large and located under the water column or in the ground. A special liquid with antifreeze or water can circulate inside.
What is geothermal heating
In order to equip geothermal heating with your own hands, you should familiarize yourself with the concept of this expression and the basic principles of work. So, the coolant takes the temperature of the medium and enters the heat pump in a heated form. The accumulated heat enters the internal circuit. This contributes to the heating of water in radiators and pipes. The heat pump is a key element. This unit is small and takes up no more space than a washing machine.
How much heat energy to count
If you are interested in performance, then for every kilowatt of electricity consumed, the pump will produce about 4 kW of thermal energy. A conventional air conditioner, which works on a similar principle, will produce 1 kW of heat per 1 kW of electricity. The device of this type of heating is the most expensive and time-consuming today. Its value is determined by the purchase of equipment and earthwork. The thrifty owner wonders if it is possible to save. You can do this by equipping the system with your own hands.
About the horizontal heat exchanger
If you want to equip geothermal heating with your own hands, you should know that quite often a horizontal circuit is used. In this case, the pipes are located in the trench at a greater depth than the level of freezing of the soil. The disadvantage here may be the territory that will be occupied by the contour. It should be larger than the area of the house. If this parameter is 250 m 2 , then about 600 m 2 will go under the pipes. Not every owner of private land is able to afford such a luxury. There may also be some inconvenience if the site is fenced. It is important, for example, to observe the distance from the trees.
When to choose a vertical heat exchanger
Do-it-yourself geothermal heating can also be equipped by installing a vertical heat exchanger. This will not require such an impressive area, but you will have to use special drilling equipment, equipping the system with your own hands. Geothermal heating from a well is also possible. The depth of the well will depend on the technology and varies from 50 to 200 m, but the service life reaches 100 years. This method is especially relevant when heating is arranged in a house with an adjacent territory on which the landscape will be preserved.
Should I use a water-based heat exchanger
If you decide to arrange geothermal heating yourself, you should consider a water-based heat exchanger. This installation is the most economical. It is recommended if the distance to the nearest body of water is less than 100 m. In this case, the pipe loop is laid to the bottom, and the depth should be approximately 2.5 m, which is below the freezing line.
The area of the reservoir should be 200 m 2 or more. The main feature is that labor-intensive excavation work does not have to be done, but the permission of the relevant services remains to be obtained. Of all these types, perhaps only the last option is quite simple to implement with your own hands.
Work order
To heat the house, it will not be possible to find specialists who would agree to drill a well for 1.5 km. But if you live in an area where hot water rises from the ground, then the cost of heating will be minimal. The first task will be to determine the depth and location of occurrence of the nearest hot reservoir. At the second stage, it will be necessary to drill a well or two. One at a time, hot water will enter the house through a pump; on the other, it will come back. In the latter case, it will be cooled.
At the next stage, when installing a geothermal heating system at home, it will be necessary to install and debug the operation of the heat pump. The same applies to pipes through which water from the source will be extracted and pumped. In-house heating equipment will be standard. It can be batteries or hidden thermal communications, or rather, a warm floor.
Sealed springs do not always contain distilled water. Due to impurities and salts, water may not be suitable for direct supply to radiators and steam heating pipes. The temperature of several sources is so high that it will destroy the highway. In order to avoid this, water from the source using a radiator heats the water from the water supply, which is then collected into the batteries. This method is called indirect. It allows you to warm up and wash, because the heat of some sources is enough for two tasks at once.
Specialist advice
Exhausted cooled water can serve as a returning liquid. You can also dial it using a pump from a nearby reservoir. The energy efficiency of this design will be higher than the energy costs for the operation of the pump. Given the environmental cleanliness, absolute safety and full occupancy of the energy carrier, the use of geothermal energy can be recommended to everyone who has access to it.
Do-it-yourself pump
If you are familiar with the action scheme and the device of the heat pump, then assembling it yourself will not be difficult. Before work, the parameters of the future system should be calculated. If you decide to equip geothermal air heating with your own hands, then you can use the simplest option - the air-water system. The work will not be accompanied by manipulations on the device of the external circuit, which is present in soil and water varieties of pumps.
For installation, two channels are required, one of them will supply air, and the second - the spent mass is discharged. In addition to the fan, you should take care of the presence of a compressor with the necessary power. For such a unit, a compressor that is in the split system is suitable. It is not necessary to purchase a new unit; you can borrow it from old equipment. It is better if this knot has a spiral variety. These compressors have sufficient efficiency and create the right pressure, which helps to increase the temperature.
Geothermal heating itself can be created if you arrange a condenser. He will need a copper pipe and a container. From the first, a coil is made. For this, a cylindrical body of the required diameter is used. A copper pipe is wound around it. The finished coil is installed in a container that is cut in half.
For the tank, it is better to use materials that during operation will show resistance to corrosion processes. After being placed inside the coil, half of the tank should be welded. Before you make geothermal heating at home with your own hands, you must determine the area of the coil using the following formula: MT / 0.8 RT. In it, MT is the power of thermal energy that will be issued by the system. The number is the coefficient of thermal conductivity when water interacts with the material of the coil. At the inlet and outlet, the water will have a different temperature, this difference is indicated by the last two letters in the formula.
Do-it-yourself geothermal heating of the garage can be arranged on the same principle. In this case, when choosing a pipe, you should pay attention to how thick the walls have. This parameter should be 1 mm or more. Otherwise, the pipe will deform at the time of winding. In the upper part of the tank, place the pipe through which the refrigerant will flow. The system provides for a heat pump evaporator. It can be made in two versions. The first is a container with a coil, the second is a pipe in a pipe. The temperature of the liquid in the evaporator will be small, so the container can be made of a plastic barrel. There is placed a circuit that is made of a copper pipe.
The coil of the evaporator coil, in contrast to the condenser, must correspond to the height of the tank and its diameter. By making a geothermal pump for heating, you can make an evaporator in the form of a pipe-in-pipe system. In this embodiment, the refrigerant pipe is placed in a plastic pipe of a larger diameter. Water will circulate through it. The pipe should have a length that will depend on the power of the pump. This parameter can vary from 25 to 40 m. This pipe must be coiled.
Shut-off and control valves will include a thermostatic valve. A needle is used as the locking element. Its position is determined by the temperature in the evaporator. This element has a complex structure, in its composition:
- diaphragm;
- thermal bulb;
- capillary tube;
- thermocouple.
These components may fail if exposed to high temperatures. During soldering, the valve must be insulated with asbestos cloth. The control valve must match the evaporator capacity. Equipping the geothermal heating of the house with your own hands, at the next stage after the manufacture of the main parts, you will need to assemble the structure in one block. The most critical step is to pump refrigerant or coolant. It’s unlikely that you can carry out such an operation yourself. It is necessary to turn to professionals who are involved in the maintenance and repair of HVAC equipment. Specialists in this field have the necessary equipment. They can charge with refrigerant and test the system. Self-injection can cause structural failure and lead to serious injuries.
To start the system you will need special equipment. At this stage, the starting load should be 40 A. Without a starting relay, you can not do here. After this step, the refrigerant and valve pressure should be adjusted. The choice of refrigerant should be taken seriously. This substance is the main carrier of thermal energy. Of the refrigerants known today, Freons are the most popular. These are hydrocarbon derivatives of compounds in which carbon atoms are replaced by other elements.
Heating from the fridge. Tools and materials
If you want to equip your own geothermal heating from the refrigerator, then the compressor will be at the heart of the system, which must be working. To repair this part is unprofitable, in addition, the performance of the homemade product will remain in question. To assemble the structure, you need a thermostatic valve. It is better if all the components are from one system, then it will be quite simple to combine them. For mounting the heat pump, brackets should be used, the length of which is 30 cm. You will also have to purchase copper pipes, a sealed container, a plastic tank and polymer pipes.
The compressor should be mounted on the wall using brackets, after which the production of the capacitor can begin. The metal tank is cut by a grinder, in one part it will be necessary to install a copper coil. The container is welded; after that, threaded holes should be prepared in it. A copper pipe is wound around a steel tank. The tank capacity should be 120 liters. The ends of the turns must be secured with rails. To the conclusions you need to connect plumbing junctions. The coil should be fixed to the plastic tank. It will be used as an evaporator. It does not overheat, so it is not necessary to take a metal container. The finished evaporator is attached to the wall.
The locking device and the connection features will depend on the type of circuit. It can be water-ground, water-air or water-water. In the first case, the collector is installed below the freezing line of the soil, and the pipes should be at the same depth. If you have chosen a water-air system, then it will be mounted quite simply, since excavation is not required. For mounting the collector, a place near the house or on the roof is suitable. The collector design will have to be assembled from polymer pipes, if you choose a water-water system. After that, the assembled circuit descends to the center of the reservoir.
Reviews
Reviews of geothermal heating are good and bad. Among the positive, it should be noted that such a scheme excludes fuel combustion. Consumers like acoustic comfort because the pump runs silently. In addition, it is impossible not to highlight the economic benefits and environmental factors.
Systems of this kind, as users emphasize, are compact and multifunctional. But there are drawbacks, one of them is the cost that you will have to go to when installing the system and preparing it for work.