How to choose the right heat pump? Heat pump for home heating: principle of operation The operation of a heat pump for home heating.
This autumn, there has been an aggravation in the network about heat pumps and their use for heating country houses and summer cottages. In a country house that I built with my own hands, such a heat pump has been installed since 2013. This is a semi-industrial air conditioner that can effectively work for heating at outdoor temperatures down to -25 degrees Celsius. It is the main and only heating device in a one-story country house with a total area of 72 square meters.
2. Briefly recall the background. Four years ago, a plot of 6 acres was bought in a garden partnership, on which, with my own hands, without involving hired labor, I built a modern energy-efficient country house. The purpose of the house is the second apartment, located in nature. Year-round, but not permanent operation. Required maximum autonomy in conjunction with simple engineering. In the area where the SNT is located, there is no main gas and you should not count on it. There remains imported solid or liquid fuel, but all these systems require complex infrastructure, the cost of construction and maintenance of which is comparable to direct heating with electricity. Thus, the choice was already partly predetermined - electric heating. But here a second, no less important point arises: the limitation of electrical capacities in the garden partnership, as well as rather high electricity tariffs (at that time - not a “rural” tariff). In fact, 5 kW of electric power has been allocated to the site. The only way out in this situation is to use a heat pump, which will save on heating by about 2.5-3 times, compared with the direct conversion of electrical energy into heat.
So let's move on to heat pumps. They differ in where they take heat from and where they give it away. An important point, known from the laws of thermodynamics (8th grade of high school) - a heat pump does not produce heat, it transfers it. That is why its COP (energy conversion factor) is always greater than 1 (that is, the heat pump always gives off more heat than it consumes from the network).
The classification of heat pumps is as follows: "water - water", "water - air", "air - air", "air - water". Under the "water" indicated in the formula on the left is meant the removal of heat from the liquid circulating coolant passing through pipes located in the ground or a reservoir. The efficiency of such systems practically does not depend on the season and ambient temperature, but they require expensive and time-consuming earthworks, as well as the availability of sufficient free space for laying a soil heat exchanger (on which, subsequently, anything will grow poorly in summer, due to freezing of the soil) . The "water" indicated in the formula on the right refers to the heating circuit located inside the building. It can be either a system of radiators or liquid underfloor heating. Such a system will also require complex engineering work inside the building, but it also has its advantages - with the help of such a heat pump, you can also get hot water in the house.
But the category of air-to-air heat pumps looks the most interesting. In fact, these are the most common air conditioners. While working for heating, they take heat from the outdoor air and transfer it to the air heat exchanger located inside the house. Despite some drawbacks (serial models cannot operate at ambient temperatures below -30 degrees Celsius), they have a huge advantage: such a heat pump is very easy to install and its cost is comparable to conventional electric heating using convectors or an electric boiler.
3. Based on these considerations, Mitsubishi Heavy duct semi-industrial air conditioner, model FDUM71VNX, was chosen. As of autumn 2013, a set consisting of two blocks (external and internal) cost 120 thousand rubles.
4. The outdoor unit is installed on the facade on the north side of the house, where there is the least wind (this is important).
5. The indoor unit is installed in the hall under the ceiling, from which, with the help of flexible soundproof air ducts, hot air is supplied to all living spaces inside the house.
6. Because the air supply is located under the ceiling (it is absolutely impossible to organize the supply of hot air near the floor in a stone house), it is obvious that you need to take the air on the floor. To do this, with the help of a special box, the air intake was lowered to the floor in the corridor (in all interior doors, overflow grilles were also installed in the lower part). Operating mode - 900 cubic meters of air per hour, due to constant and stable circulation, there is absolutely no difference in air temperature between the floor and ceiling in any part of the house. To be precise, the difference is 1 degree Celsius, which is even less than when using wall-mounted convectors under windows (with them, the temperature difference between floor and ceiling can reach 5 degrees).
7. In addition to the fact that the indoor unit of the air conditioner, due to the powerful impeller, is able to drive large volumes of air around the house in recirculation mode, one should not forget that people need fresh air in the house. Therefore, the heating system also acts as a ventilation system. Through a separate air duct from the street, fresh air is supplied to the house, which, if necessary, is heated (during the cold season) using automation and a channel heating element.
8. Distribution of hot air is carried out through these grilles located in the living rooms. It is also worth paying attention to the fact that there is not a single incandescent lamp in the house and only LEDs are used (remember this point, this is important).
9. Waste "dirty" air is removed from the house through the hood in the bathroom and in the kitchen. Hot water is prepared in a conventional storage water heater. In general, this is a fairly large expense item, because. the well water is very cold (between +4 and +10 degrees Celsius depending on the time of year) and one might reasonably notice that solar collectors can be used to heat water. Yes, you can, but the cost of investing in infrastructure is such that for this money you can heat water directly with electricity for 10 years.
10. And this is "TsUP". Air source heat pump master and main controller. It has various timers and simple automation, but we use only two modes: ventilation (during the warm season) and heating (during the cold season). The built house turned out to be so energy efficient that the air conditioner in it was never used for its intended purpose - to cool the house in the heat. LED lighting played a big role in this (heat transfer from which tends to zero) and very high-quality insulation (it's no joke, after arranging the lawn on the roof, we even had to use a heat pump this summer to heat the house - on days when the average daily temperature dropped below + 17 degrees Celsius). The temperature in the house is maintained year-round at least +16 degrees Celsius, regardless of the presence of people in it (when there are people in the house, the temperature is set to +22 degrees Celsius) and the supply ventilation never turns off (because laziness).
11. The meter for technical electricity metering was installed in the fall of 2013. That is exactly 3 years ago. It is easy to calculate that the average annual consumption of electrical energy is 7000 kWh (in fact, this figure is slightly lower now, because in the first year the consumption was high due to the use of dehumidifiers during finishing work).
12. In the factory configuration, the air conditioner is capable of heating at an ambient temperature of at least -20 degrees Celsius. To work at lower temperatures, refinement is required (in fact, it is relevant when operating even at a temperature of -10, if the humidity is high outside) - installing a heating cable in a drainage pan. This is necessary so that after the defrosting cycle of the outdoor unit, the liquid water has time to leave the drain pan. If she does not have time to do this, then ice will freeze in the pan, which will subsequently squeeze out the frame with the fan, which will probably lead to the breaking of the blades on it (you can see photos of the broken blades on the Internet, I almost encountered this myself because . did not put down the heating cable immediately).
13. As I mentioned above, LED lighting is used everywhere in the house. This is important when it comes to air conditioning a room. Let's take a standard room in which there are 2 lamps, 4 lamps in each. If these are 50 watt incandescent lamps, then in total they consume 400 watts, while LED lamps will consume less than 40 watts. And all energy, as we know from the physics course, eventually turns into heat anyway. That is, incandescent lighting is such a good medium-power heater.
14. Now let's talk about how a heat pump works. All it does is transfer heat energy from one place to another. This is how refrigerators work. They transfer heat from the refrigerator to the room.
There is such a good riddle: How will the temperature in the room change if you leave the refrigerator plugged into the outlet with the door open? The correct answer is that the temperature in the room will rise. For a simple understanding, this can be explained as follows: the room is a closed circuit, electricity flows into it through the wires. As we know, energy eventually turns into heat. That is why the temperature in the room will rise, because electricity enters the closed circuit from the outside and remains in it.
A bit of theory. Heat is a form of energy that is transferred between two systems due to temperature differences. In this case, thermal energy is transferred from a place with a high temperature to a place with a lower temperature. This is a natural process. Heat transfer can be carried out by conduction, thermal radiation or by convection.
There are three classical aggregate states of matter, the transformation between which is carried out as a result of a change in temperature or pressure: solid, liquid, gaseous.
To change the state of aggregation, the body must either receive or give off thermal energy.
During melting (transition from a solid to a liquid state), thermal energy is absorbed.
During evaporation (transition from a liquid to a gaseous state), thermal energy is absorbed.
During condensation (transition from a gaseous state to a liquid state), thermal energy is released.
During crystallization (transition from a liquid to a solid state), thermal energy is released.
The heat pump uses two transient modes in its operation: evaporation and condensation, that is, it operates with a substance that is either in a liquid or in a gaseous state.
15. The refrigerant R410a is used as the working fluid in the heat pump circuit. It is a fluorocarbon that boils (changes from liquid to gas) at very low temperatures. Namely, at a temperature of - 48.5 degrees Celsius. That is, if ordinary water boils at a temperature of +100 degrees Celsius at normal atmospheric pressure, then R410a freon boils at a temperature almost 150 degrees lower. Moreover, at a very negative temperature.
It is this property of the refrigerant that is used in the heat pump. By targeted measurement of pressure and temperature, it can be given the desired properties. Either it will be evaporation at ambient temperature with the absorption of heat, or condensation at ambient temperature with the release of heat.
16. This is what the heat pump circuit looks like. Its main components are compressor, evaporator, expansion valve and condenser. The refrigerant circulates in a closed circuit of the heat pump and alternately changes its state of aggregation from liquid to gaseous and vice versa. It is the refrigerant that transfers and transfers heat. The pressure in the circuit is always excessive compared to atmospheric pressure.
How it works?
The compressor sucks in the low pressure cold refrigerant gas coming from the evaporator. The compressor compresses it under high pressure. The temperature rises (the heat from the compressor is also added to the refrigerant). At this stage, we obtain a gaseous refrigerant of high pressure and high temperature.
In this form, it enters the condenser, blown with colder air. The superheated refrigerant gives up its heat to the air and condenses. At this stage, the refrigerant is in a liquid state, under high pressure and at an average temperature.
The refrigerant then enters the expansion valve. There is a sharp decrease in pressure in it, due to the expansion of the volume that the refrigerant occupies. The decrease in pressure leads to partial evaporation of the refrigerant, which in turn reduces the temperature of the refrigerant below ambient temperature.
In the evaporator, the pressure of the refrigerant continues to decrease, it evaporates even more, and the heat necessary for this process is taken from the warmer outside air, which is then cooled.
The fully gaseous refrigerant enters the compressor again and the cycle is completed.
17. I'll try to explain again in a simpler way. The refrigerant boils already at a temperature of -48.5 degrees Celsius. That is, relatively speaking, at any higher ambient temperature, it will have excess pressure and, in the process of evaporation, will take heat from the environment (that is, street air). There are refrigerants used in low-temperature refrigerators, their boiling point is even lower, down to -100 degrees Celsius, but it cannot be used to operate a heat pump to cool a room in the heat due to very high pressure at high ambient temperatures. R410a refrigerant is a kind of balance between the ability of the air conditioner to work both for heating and cooling.
Here, by the way, is a good documentary film shot in the USSR and telling about how a heat pump works. I recommend.
18. Can any air conditioner be used for heating? No, not any. Although almost all modern air conditioners work on R410a freon, other characteristics are no less important. Firstly, the air conditioner must have a four-way valve that allows you to switch to “reverse”, so to speak, namely, to swap the condenser and evaporator. Secondly, please note that the compressor (it is located on the lower right) is located in a thermally insulated casing and has an electric crankcase heater. This is necessary in order to always maintain a positive oil temperature in the compressor. In fact, at an ambient temperature below +5 degrees Celsius, even in the off state, the air conditioner consumes 70 watts of electrical energy. The second, most important point - the air conditioner must be inverter. That is, both the compressor and the impeller electric motor must be able to change performance during operation. This is what allows the heat pump to work efficiently for heating at outdoor temperatures below -5 degrees Celsius.
19. As we know, on the heat exchanger of the outdoor unit, which is the evaporator during heating operation, intensive evaporation of the refrigerant occurs with the absorption of heat from the environment. But in the street air there are water vapors in a gaseous state, which condense, or even crystallize on the evaporator due to a sharp drop in temperature (the street air gives up its heat to the refrigerant). And intensive freezing of the heat exchanger will lead to a decrease in the efficiency of heat removal. That is, as the ambient temperature decreases, it is necessary to “slow down” both the compressor and the impeller in order to ensure the most efficient heat removal on the evaporator surface.
An ideal heat pump for heating only should have a surface area of the external heat exchanger (evaporator) several times the surface area of the internal heat exchanger (condenser). In practice, we return to the very balance that the heat pump must be able to work both for heating and cooling.
20. On the left, you can see the external heat exchanger almost completely covered with frost, except for two sections. In the upper, not frozen, section, freon still has a sufficiently high pressure, which does not allow it to effectively evaporate with the absorption of heat from the environment, while in the lower section it is already overheated and can no longer take heat from the outside. And the photo on the right gives an answer to the question why the external unit of the air conditioner was installed on the facade, and not hidden from view on a flat roof. It is because of the water that needs to be diverted from the drainage pan in the cold season. It would be much more difficult to drain this water from the roof than from the blind area.
As I already wrote, during heating operation at a negative temperature outside, the evaporator on the outdoor unit freezes over, water from the outdoor air crystallizes on it. The efficiency of a frozen evaporator is noticeably reduced, but the air conditioner electronics automatically controls the heat removal efficiency and periodically switches the heat pump to the defrost mode. In fact, the defrost mode is a direct conditioning mode. That is, heat is taken from the room and transferred to an external, frozen heat exchanger in order to melt the ice on it. At this time, the fan of the indoor unit runs at minimum speed, and cool air comes out of the air ducts inside the house. The defrost cycle usually lasts 5 minutes and occurs every 45-50 minutes. Due to the high thermal inertia of the house, no discomfort is felt during defrosting.
21. Here is a table of heat output for this heat pump model. Let me remind you that the nominal energy consumption is just over 2 kW (current 10A), and the heat transfer ranges from 4 kW at -20 degrees outside, up to 8 kW at a street temperature of +7 degrees. That is, the conversion factor is from 2 to 4. It is how many times the heat pump saves energy compared to the direct conversion of electrical energy into heat.
By the way, there is another interesting point. The resource of the air conditioner when working for heating is several times higher than when working for cooling.
22. Last fall, I installed the Smappee electric energy meter, which allows you to keep statistics on energy consumption on a monthly basis and provides a more or less convenient visualization of the measurements taken.
23. Smappee was installed exactly one year ago, in the last days of September 2015. It also attempts to show the cost of electricity, but does so based on manually set rates. And there is an important point with them - as you know, we raise electricity prices 2 times a year. That is, for the presented measurement period, tariffs changed 3 times. Therefore, we will not pay attention to the cost, but calculate the amount of energy consumed.
In fact, Smappee has problems with the visualization of consumption graphs. For example, the shortest column on the left is the consumption for September 2015 (117 kWh). something went wrong with the developers and for some reason there are 11, not 12 columns on the screen for a year. But the total consumption figures are calculated accurately.
Namely, 1957 kWh for 4 months (including September) at the end of 2015 and 4623 kWh for the whole of 2016 from January to September inclusive. That is, a total of 6580 kWh was spent on ALL the life support of a country house, which was heated all year round, regardless of the presence of people in it. Let me remind you that in the summer of this year for the first time I had to use a heat pump for heating, and for cooling in the summer it did not work even once in all 3 years of operation (except for automatic defrost cycles, of course). In rubles, at current tariffs in the Moscow region, this is less than 20 thousand rubles a year, or about 1,700 rubles a month. Let me remind you that this amount includes: heating, ventilation, water heating, stove, refrigerator, lighting, electronics and appliances. That is, it is actually 2 times cheaper than the monthly payment for an apartment in Moscow of the same area (of course, excluding maintenance fees, as well as fees for major repairs).
24. And now let's calculate how much money the heat pump saved in my case. We will compare with electric heating, using the example of an electric boiler and radiators. I will count at pre-crisis prices, which were at the time of the installation of the heat pump in the fall of 2013. Now heat pumps have risen in price due to the collapse of the ruble, and the equipment is all imported (the leaders in the production of heat pumps are the Japanese).
Electric heating:
Electric boiler - 50 thousand rubles
Pipes, radiators, fittings, etc. - another 30 thousand rubles. Total materials for 80 thousand rubles.
Heat pump:
Channel air conditioner MHI FDUM71VNXVF (outdoor and indoor unit) - 120 thousand rubles.
Air ducts, adapters, thermal insulation, etc. - another 30 thousand rubles. Total materials for 150 thousand rubles.
Do-it-yourself installation, but in both cases it is about the same in time. Total "overpayment" for a heat pump compared to an electric boiler: 70 thousand rubles.
But that's not all. Air heating using a heat pump is at the same time air conditioning in the warm season (that is, air conditioning still needs to be installed, right? So we’ll add at least another 40 thousand rubles) and ventilation (mandatory in modern sealed houses, at least another 20 thousand rubles).
What do we have? "Overpayment" in the complex is only 10 thousand rubles. It is still at the stage of putting the heating system into operation.
And then the operation begins. As I wrote above, in the coldest winter months the conversion factor is 2.5, and in the off-season and summer it can be taken equal to 3.5-4. Let's take the average annual COP equal to 3. Let me remind you that 6,500 kWh of electrical energy is consumed in a house per year. This is the total consumption of all electrical appliances. Let's take for simplicity of calculations at a minimum that the heat pump consumes only half of this amount. That is 3000 kWh. At the same time, on average, for the year he gave 9000 kWh of thermal energy (6000 kWh "dragged" from the street).
Let's translate the transferred energy into rubles, assuming that 1 kWh of electrical energy costs 4.5 rubles (average day/night tariff in the Moscow region). We get 27,000 rubles of savings, compared with electric heating only for the first year of operation. Recall that the difference at the stage of putting the system into operation was only 10 thousand rubles. That is, already for the first year of operation, the heat pump SAVED me 17 thousand rubles. That is, it paid off in the first year of operation. At the same time, let me remind you that this is not a permanent residence, in which the savings would be even greater!
But do not forget about the air conditioner, which specifically in my case was not required due to the fact that the house I built turned out to be over-insulated (although a single-layer aerated concrete wall is used without additional insulation) and it simply does not heat up in the summer in the sun. That is, we will throw off 40 thousand rubles from the estimate. What do we have? In this case, I began to SAVE on the heat pump not from the first year of operation, but from the second. It's not a big difference.
But if we take a water-to-water heat pump or even an air-to-water heat pump, then the figures in the estimate will be completely different. That is why an air-to-air heat pump offers the best price/performance ratio on the market.
25. And finally, a few words about electric heaters. I was tormented by questions about all sorts of infrared heaters and nano-technologies that do not burn oxygen. I will answer briefly and to the point. Any electric heater has an efficiency of 100%, that is, all electrical energy is converted into heat. In fact, this applies to any electrical appliances, even an electric light bulb gives off heat exactly in the amount in which it received it from the outlet. If we talk about infrared heaters, then their advantage lies in the fact that they heat objects, not air. Therefore, the most reasonable application for them is heating on open verandas in cafes and at bus stops. Where there is a need to transfer heat directly to objects / people, bypassing air heating. A similar story about the burning of oxygen. If somewhere in the brochure you see this phrase, you should know that the manufacturer is holding the buyer for a sucker. Combustion is an oxidation reaction, and oxygen is an oxidizing agent, that is, it cannot burn itself. That is, this is all the nonsense of amateurs who skipped physics lessons at school.
26. Another option for saving energy with electric heating (whether by direct conversion or using a heat pump) is to use the heat capacity of building envelopes (or a special heat accumulator) to store heat using a cheap night electric tariff. That's what I'll be experimenting with this winter. According to my preliminary calculations (taking into account the fact that next month I will pay the village electricity tariff, because the building is already registered as a residential building), even despite the increase in electricity tariffs, next year I will pay for the maintenance of the house less than 20 thousand rubles (for all consumed electrical energy for heating, water heating, ventilation and equipment, taking into account the fact that the house is maintained at a temperature of about 18-20 degrees Celsius all year round, regardless of whether there are people in it).
What is the result? A heat pump in the form of a low-temperature air-to-air conditioner is the easiest and most affordable way to save on heating, which can be doubly important when there is a limit on electrical power. I am completely satisfied with the installed heating system and do not experience any discomfort from its operation. In the conditions of the Moscow region, the use of an air source heat pump fully justifies itself and allows you to recoup the investment no later than in 2-3 years.
By the way, do not forget that I also have Instagram, where I publish the progress of work almost in real time -
Heat pumps are becoming more and more popular. With the help of these devices, you can heat (cool) houses and organize hot water supply, significantly saving.
It is rather difficult for people who are far from physics to understand the principle of operation of heat pumps, and therefore a lot of misconceptions are circulated on the Internet, which are used by unscrupulous manufacturers and sellers. In this article, we will try to explain in an accessible form the principle of operation and dispel some of the myths that this wonderful unit managed to acquire.
pros
From the school bench we know that under normal conditions, a colder substance cannot give up its heat to a hotter one, but on the contrary, it heats up from it until their temperatures are equal. This is the holy truth. But the heat pump creates such conditions that a colder environment begins to give up its heat to a warmer one, while cooling even more.
The simplest overused example of a heat pump is a refrigerator. In it, heat is pumped out from a colder chamber into a warmer room in the kitchen. At the same time, the freezer cools even more, and the kitchen heats up even more from the radiator located on the back of the refrigerator.
The principle of operation of most heat pumps is based on the properties of intermediate heat carriers (gases, most often freons) that are used in these machines. It is freons that are the mediator that allows you to take heat from a colder body, giving it to a hotter one.
Surely you have noticed that if you quickly release compressed gas from a lighter refill can, it evaporates and cools the can, which can become covered with frost even in hot weather. The opposite is also true: when compressed, the gas heats up. With this in mind, it will not be difficult for you to understand the principle of operation of a heat pump, the simplest diagram of which is shown in the figure.
Heat pump components
The simplest heat pump consists of four major components:
- evaporator;
- capacitor;
- compressor;
- capillary.
The compressor compresses the freon to a liquid state in the condenser, which then heats up. It is this heat that can be used in heating or in hot water supply by organizing the simplest heat exchange between a hot condenser and a colder room or boiler.
Passing through the condenser, the liquefied freon is cooled, giving off heat during heat exchange to heating radiators or underfloor heating pipes, and begins to condense. Passing through the capillary into the evaporator, freon becomes gaseous again, while cooling the evaporator (remember the frost on the can?).
In order for the process not to stop, it is necessary to constantly supply heat to the evaporator, otherwise the freon will simply stop evaporating there, because the temperature of the evaporator can drop significantly during the constant operation of the compressor. Even a temperature of minus thirty, supplied to the evaporator, may be sufficient to maintain evaporation, because the evaporation temperature of the gases used in heat pumps is much lower than this value.
Suppose the freon evaporation temperature is minus sixty degrees Celsius, and we blow the evaporator with frosty street air, with a temperature of minus thirty - freon, of course, will evaporate, taking heat even from such cold air. Thus, it turns out that the heat pump, as it were, pumps the temperature from a colder environment to a warmer one.
What to look for when buying?
This effect gives rise to many myths that are used by unscrupulous "sold" in order to better sell their products.
The most common myth is the assertion that the efficiency of heat pumps exceeds one. It is clear that this statement is pure nonsense. In fact, the efficiency of heat engines cannot be more than one, and even for modern heat pumps it is quite small - less than that of the cheapest oil heater. People just often confuse efficiency and the so-called COP (COP).
COP is more of an economic factor than a physical one. It shows the ratio of paid electricity for pumping free heat from the street to the amount of heat entering the room. Those. COP 5 - this simply means that in order to pump 5 kW of free heat from the street to the house, we spent 1 kW of paid electricity. It's just that COP does not take into account free thermal energy from the street, but considers only the one that was received as a result and what was spent for this.
Another myth is also related to COP: in the passports of heat pumps and on the price tags, sellers proudly indicate a single COP value, which simply misleads buyers. The fact is that the COP of heat pumps is a variable, not a constant. And many unscrupulous businessmen are silent about this, because they indicate the COP for the most favorable conditions, when it is almost the maximum. And this is already much more dangerous than the delusions about the over-unit efficiency, because fraught with real consequences.
Imagine that you believe that you will spend 1 kW of electricity to produce 5 kW of heat for the same heating in winter, because the heat pump passport indicates that COP = 5. We bought a heat pump with the necessary power, assembled a heating system ... And at the most inopportune moment, when the frosts are the most severe, your heater eats not 1 to 5, but 1 to 2 in the best case, or is not able to give out the necessary heat for heating at all. And here comes the understanding that it is possible to heat specifically with this system only in the off-season ... A very unpleasant situation is to give a lot of money and still be heated in cold weather with cheap oil radiators, and only because they relied on COP and stable, irreducible heat generation.
From year to year, before buying equipment for heating their home, consumers have a legitimate question about saving money on the heating process. This moment excites many because of the constant rise in prices for all known types of fuel. Several decades ago, scientists proposed an alternative option - to extract energy from the surrounding space. This system is called heating heat pumps and is effectively used in European countries and Japan.
Tasks solved by installing a heat pump
The equipment allows you to heat the house and maintain a constant temperature in the cold season. In summer, such a system will help to avoid heat in the room, since many pumps are equipped with a reverse cooling function. Each owner has the right to choose for himself the only acceptable type of home heating and water heating. But the main aspects of the use of thermal units, which determine the demand, are: environmental friendliness, operational safety, comfortable conditions, efficiency, long life, acceptable design.
The annual increase in the price of energy carriers leads to the fact that consumers prefer to install expensive equipment for home heating, which does not require further expenses for the purchase of gas, solid or liquid fuel. Heat pumps do not require major periodic maintenance and last longer.
In some houses over 150 m2, geothermal heating methods are used along with a backup heating boiler. Such a combination allows you to recoup the investment after 5 years of use. The heat of the earth with low potentiality is converted by the pump into a permanent heat carrier with a temperature not lower than 75ºС. At the same time, the spent kilowatt of electrical energy contributes to the release of about 6 kilowatts of heat.
During the summer, the passive cooling model allows the circulation of a coolant circuit, which is cooled in the ground, where the temperature is 5-7ºС. The electricity spent on the operation of the circulation pump is much cheaper than the operation of standard air conditioning throughout the entire area of the house in the hot season.
To increase the efficiency of the pump, you can connect additional circuits for heating the pool to it, use the energy of a solar collector in summer.
Pumps for heat pipelines
Description
The planet is a hot core covered with a thick layer of solid matter. Someday the core will cool down, because unlike the stars, the earth does not have its own source of heat. But it is not worth talking about the duration of the period during which the soil temperature will change, since even our civilization will not feel this. That is why soil at a relatively shallow depth of up to 50 m exists in a constantly heated state, with a temperature of about 12ºС. Depth may vary depending on local climate.
Geothermal heat pumps can be used even in permafrost zones, but you will have to look for heat at great depths.
Operating principle
The heat pump is used to extract low energy heat from the environment. It converts it into high-temperature energy for transfer to the coolant in the heating circuit. Pump operation is based on the application of physical and chemical laws. The masses of air, water and earth around constantly accumulate solar energy, which is used in the heating system.
Installing a heat pump is like operating a refrigerator, only in reverse order. The refrigeration unit has a freezer (evaporator), which supplies him with cold. Excess heat enters the condenser grill at the back of the refrigerator and is released into the air.
The heat pump has an evaporator located in such a place that it is in contact with a low heat source of natural energy:
- layers of the bowels of the earth located below the freezing point of the surface using inclined or vertical wells;
- water depths of thermal non-freezing reservoirs lowering to the desired depth;
- air masses outside the house.
In such a geothermal device, the condenser works as a heat exchange device that gives off heat to heat the coolant in the heating circuit of the house, which is supplied for final distribution to heaters and radiators.
For an expanded concept, we present circuit in which the chemical element refrigerant moves present there in the form of a liquid or gas. Its movement occurs due to the operation of the compressor. The refrigerant heats up when compressed, so an expansion valve is added to the design.
The system has two heat exchangers. One of them works as an evaporator in the cold area and serves to lower the temperature of the air or water in the same way as an air conditioner or refrigerator. The second one works as a condenser in the hot area and heats the water for the heating system.
The remaining action is to identify a source for collecting heat, which gives energy to probes, long pipe loops at the bottom of reservoirs or below the freezing point, air sources.
Three circuits in a heat pump system:
Manufacturers predict a service life of at least 20 years, but concepts such as friction and wear will disable the pump much earlier. In reality, it is possible to set the duration of operation of thermal equipment without repair at 10–12 years.
Natural heat sources
Earth's interior
They are a free heat generator. At a depth where the soil never freezes, a positive stable temperature is maintained, which does not change depending on the season.
To collect low-temperature heat from the soil, two methods are used:
- drilling of vertical collectors wells to a depth of 50 to 200 m to take water and run it through a heat exchanger and transfer it to a reservoir after use;
- laying pipeline on the site of the house at a depth of more than one meter and a distance between the contours of at least one meter with backfilling and watering with moisture.
Water
It is possible to collect a sufficient amount of heat in water masses if there is a non-freezing lake with running water or groundwater rises high. A long pipeline is laid at the bottom, fixed with the help of weights, which are set at the rate of 5 kg per 1 linear meter. For the operation of a heat exchanger with a length of approximately 300 meters to be effective, the distance between the turns of the pipes should not be less than 1.5 m.
To operate such a system, the principle of open heat collection is most often used. It implies that two wells are made along the movement of groundwater, the first one serves to collect water with a pump and supply it to a heat exchanger. In the second, the used chilled water is discharged.
The risk of disruption is that the height of the groundwater rise may vary depending on the rainy season and the movement of land layers.
Air
The most common and easily accessible source of heat is the atmosphere. The heat exchanger is made like a large radiator with a sufficient number of fins and a blower fan. Such a heat pump is designed for heating and for supplying hot water to the owners of the house. Often the simplest devices of this type are used to heat water in winter pools. The cost of electrical energy is minimal.
External heat exchangers are mounted on the roof of the house or on its wall. If powerful equipment is supposed, then for its installation it is necessary to create an additional foundation in the form of a foundation.
Thermal installations that extract heat from the atmosphere are mostly inverter-based. They convert alternating current which allows the compressor to operate at full capacity. When the coolant is heated to the desired temperature, the equipment does not stop, only the power decreases. Thus, the service life of the equipment is increased.
Overview of heat pump types
Air-to-water pumps
They collect heat from the atmosphere and heat the liquid in the heating system. Available in standard and compact models. It can be installed both in the process of repairing a building, and during a new construction of a house. Provide heating of the heat carrier up to 60ºС at outside temperatures up to -20ºС. With the most difficult work, the power reaches 20 kW. Some systems are supplied with additional heating by means of electricity for operation in extreme conditions or heating the system for defrosting.
Thermal system "brine-water"
It receives energy from the bowels of the earth through the installation of special geothermal probes. Two expansion heat exchangers are installed in the system, which work for heat and cooling. Plant power 16 kW. A new design system is used, consisting of up to 6 modules connected in series, consuming a total power of up to 50 kW.
Thermal installation "water-water"
The pumps are of high quality built into the manufacturing process. They have a heat exchanger in the form of plates in the design. Almost all important elements are made of stainless steel and its alloys. The expansion tank can be easily connected to soil pumps if necessary. Work power 6 kW. All models are fully automatic.
Heat pumps by type of air-to-air operation
They are able not only to heat the water, but also the air in the room. . These include split systems.. It is also possible to install a cascade version with a power of up to 50 kW.
Geothermal "soil-water"
Very well proved for heating in private houses and industrial facilities. To collect heat, wells of various depths are drilled, there are all elements of full automation of control. They work from deep or surface collectors.
The cost of equipment and installation of a heat pump
The price of a heat pump is determined by several factors. To do this, take into account the area of \u200b\u200bthe heated house, the presence of additional pipes of various heating options. In addition, the type of pump installed plays a role in terms of the principle of collecting natural heat from the environment and in terms of power.
Much attention is paid to the insulation of building envelopes, as heat loss will affect the required pump power. If for comparison use a thermal unit with a power of 10 to 20 kW, then in a house with standard heat losses (non-insulated walls) it will be able to effectively heat an area of up to 220 m2, in a carefully insulated house the space will increase to 420 m2. And in a modern dwelling completely isolated from heat losses, a pump of such power can successfully heat an area of up to 750 m2.
The price of geothermal equipment includes installation and earthworks up to the buffer tank of the heating system of the house and the cost of the heat pump.
In the case of a standard small house up to 130 m2 when using ground heat intake, the cost of equipment will be about 430,000 rubles, and installation will cost 300,000 rubles. The use of a horizontal soil collector will reduce installation costs to 150,000 rubles, but the price of equipment will remain the same.
The cheapest heating system for such a house can be considered a system of air intake of heat and its transfer to a water coolant. The price of equipment is significantly lower and amounts to about 350,000 rubles, the cost of installation is 80,000 rubles.
If we talk about deep drilling wells in areas with a low freezing point and for heating a house up to 400 m2, then the cost of equipment can reach 800,000 rubles, installation work will cost 355,000 rubles.
The use of soil, water and air heat pumps will greatly facilitate the life of the owners of the house, who will not focus on the procurement of fuel, its transportation and storage. In addition, comfort and lack of need for constant maintenance will make the system indispensable for every consumer.
It becomes more difficult to pay for electricity and heat supply every year. When building or buying new housing, the problem of economical energy supply becomes especially acute. Due to periodically recurring energy crises, it is more profitable to increase the initial costs for high-tech equipment in order to receive heat for decades at a minimum cost.
The most cost-effective option in some cases is a heat pump for home heating, the principle of operation of this device is quite simple. It is impossible to pump heat in the truest sense of the word. But the law of conservation of energy allows technical devices to lower the temperature of a substance in one volume while simultaneously heating something else.
What is a heat pump (HP)
Let's take an ordinary household refrigerator as an example. Inside the freezer, water quickly turns to ice. Outside is a grille that is hot to the touch. From it, the heat collected inside the freezer is transferred to the room air.
The same thing, but in reverse order, does TN. The radiator grill, located outside the building, is much larger in order to collect enough heat from the environment to heat the home. The coolant inside the tubes of the radiator or collector gives energy to the heating system inside the house, and then heats up again outside the house.
Device
Providing a house with heat is a more difficult technical task than cooling a small volume of a refrigerator where a compressor with freezing and radiator circuits is installed. An air HP is almost as simple, which receives heat from the atmosphere and heats the internal air. Only fans are added to blow the circuits.
It is difficult to obtain a large economic effect from the installation of an air-to-air system due to the low specific gravity of atmospheric gases. One cubic meter of air weighs only 1.2 kg. Water is about 800 times heavier, so the calorific value also has a multiple difference. From 1 kW of electrical energy spent by an air-to-air device, only 2 kW of heat can be obtained, while a water-to-water heat pump provides 5–6 kW. To guarantee such a high coefficient of performance (COP) can HP.
The composition of the pump components:
- Home heating system, for which it is better to use underfloor heating.
- Boiler for hot water supply.
- A condenser that transfers the energy collected outside to the heat carrier of the house heating.
- An evaporator that takes energy from the coolant that circulates in the external circuit.
- A compressor that pumps the refrigerant from the evaporator, converting it from a gaseous state to a liquid state, pressurizing it and cooling it down in the condenser.
- Expansion valve, installed in front of the evaporator to control the flow of refrigerant.
- The outer contour is laid on the bottom of the reservoir, buried in trenches or lowered into wells. For an air-to-air HP, the circuit is an external radiator grill, blown by a fan.
- Pumps pump coolant through pipes outside and inside the house.
- Automation for control according to a predetermined space heating program, which depends on changes in the outdoor temperature.
Inside the evaporator, the heat carrier of the external pipe register is cooled, giving off heat to the refrigerant of the compressor circuit, and then it is pumped through the pipes at the bottom of the reservoir by a pump. There it heats up and the cycle repeats again. In the condenser, heat is transferred to the heating system of the cottage.
Prices for different models of heat pumps
Heat pump
Principle of operation
The thermodynamic principle of heat transfer, discovered at the beginning of the 19th century by the French scientist Carnot, was later detailed by Lord Kelvin. But the practical use of their work, dedicated to solving the problem of home heating from alternative sources, appeared only in the last fifty years.
In the early 1970s, the first global energy crisis occurred. The search for economical ways of heating led to the creation of devices that can collect energy from the environment, concentrate it and send it to heat the house.
As a result, a HP design was developed with several interacting thermodynamic processes:
- When the refrigerant of the compressor circuit enters the evaporator, the pressure and temperature of the freon almost instantly decrease. The resulting temperature difference contributes to the selection of thermal energy from the coolant of the external collector. This phase is called isothermal expansion.
- Then adiabatic compression occurs - the compressor increases the pressure of the refrigerant. At the same time, its temperature rises to +70 °C.
- Passing the condenser, freon becomes a liquid, since at elevated pressure it gives off heat to the in-house heating circuit. This phase is called isothermal compression.
- When freon passes the throttle, pressure and temperature drop sharply. Adiabatic expansion occurs.
Heating the internal volume of the room according to the HP principle is possible only with the use of high-tech equipment equipped with automation to control all of the above processes. In addition, programmable controllers regulate the intensity of heat generation according to fluctuations in the outdoor temperature.
Alternative fuel for pumps
It is not necessary to use carbon fuel in the form of firewood, coal, gas for the operation of HP. The source of energy is the heat of the planet dissipated in the surrounding space, inside which there is a permanently operating nuclear reactor.
The solid shell of continental plates floats on the surface of hot liquid magma. Sometimes it breaks out during volcanic eruptions. Near the volcanoes there are geothermal springs, where even in winter you can swim and sunbathe. A heat pump is able to collect energy almost anywhere.
To work with various sources of dissipated heat, there are several types of HP:
- "Air-to-air". It extracts energy from the atmosphere and heats the air masses indoors.
- "Water-air". Heat is collected by an external circuit from the bottom of the reservoir for subsequent use in ventilation systems.
- "Soil-water". Pipes for collecting heat are located horizontally underground below the freezing level, so that even in the most severe frost they receive energy to heat the coolant in the heating system of the building.
- "Water-water". The collector is laid out along the bottom of the reservoir at a depth of three meters, the collected heat heats the water circulating in the warm floors inside the house.
There is an option with an open external collector, when two wells can be dispensed with: one for groundwater intake, and the second for draining back into the aquifer. This option is possible only with good fluid quality, because the filters quickly become clogged if the coolant contains too many hardness salts or suspended microparticles. Before installation, it is necessary to do a water analysis.
If the drilled well silts up quickly or the water contains a lot of hardness salts, then the stable operation of the HP is ensured by drilling more holes in the ground. Loops of a sealed external circuit are lowered into them. Then the wells are plugged with the help of grouting from a mixture of clay and sand.
Use of ground pumps
You can get additional benefit from areas occupied by lawns or flower beds with the help of a ground-water HP. To do this, it is necessary to lay pipes in trenches to a depth below the freezing level to collect underground heat. The distance between parallel trenches is at least 1.5 m.
In the south of Russia, even in extremely cold winters, the ground freezes to a maximum of 0.5 m, so it is easier to remove the entire layer of earth at the installation site with a grader, lay the collector, and then fill the pit with an excavator. Shrubs and trees should not be planted at this place, the roots of which can damage the outer contour.
The amount of heat received from each meter of pipe depends on the type of soil:
- dry sand, clay - 10–20 W/m;
- wet clay - 25 W/m;
- moistened sand and gravel - 35 W/m.
The area of land adjacent to the house may not be enough to accommodate an external register of pipes. Dry sandy soils do not provide sufficient heat flow. Then drilling of wells up to 50 meters deep is used to reach the aquifer. U-shaped collector loops are lowered into the wells.
The greater the depth, the higher the thermal efficiency of the probes inside the wells. The temperature of the earth's interior rises by 3 degrees every 100 m. The energy removal efficiency of a borehole collector can reach 50 W/m.
Installation and start-up of HP systems is a technologically complex set of works that can only be performed by experienced specialists. The total cost of equipment and component materials is much higher when compared with conventional gas heating equipment. Therefore, the payback period of the initial costs is stretched for years. But a house is built for decades, and geothermal heat pumps are the most profitable way of heating for country cottages.
Annual savings compared to:
- gas boiler - 70%;
- electric heating - 350%;
- solid fuel boiler - 50%.
When calculating the payback period of HP, it is worth considering the operating costs for the entire life of the equipment - at least 30 years, then the savings will many times exceed the initial costs.
Water-to-water pumps
Almost anyone can place polyethylene pipes of the collector at the bottom of a nearby reservoir. This does not require great professional knowledge, skills, tools. It is enough to evenly distribute the turns of the bay over the surface of the water. There should be a distance of at least 30 cm between the turns, and a flooding depth of at least 3 m. Then you need to tie the loads to the pipes so that they go to the bottom. Substandard brick or natural stone is quite suitable here.
The installation of a water-to-water HP collector will require significantly less time and money than when digging trenches or drilling wells. The cost of acquiring pipes will also be minimal, since the heat removal during convective heat transfer in the aquatic environment reaches 80 W/m. The obvious benefit of using HP is that there is no need to burn carbon fuel to generate heat.
An alternative way of heating a house is becoming more and more popular, because it has several more advantages:
- Environmentally friendly.
- Uses a renewable energy source.
- After the completion of commissioning, there are no regular costs of consumables.
- Automatically regulates the heating inside the house according to the outside temperature.
- The payback period for initial costs is 5–10 years.
- You can connect a boiler for hot water supply of the cottage.
- In summer, it works as an air conditioner, cooling the supply air.
- Service life of the equipment - more than 30 years.
- Minimum energy consumption - generates up to 6 kW of heat when using 1 kW of electricity.
- Full independence of heating and air conditioning of the cottage in the presence of an electric generator of any type.
- Can be adapted to the smart home system for remote control, further energy saving.
Three independent systems are required for the operation of a water-to-water HP: external, internal and compressor circuits. They are combined into one scheme by heat exchangers in which various heat carriers circulate.
When designing the power supply system, it should be taken into account that electricity is consumed for pumping the coolant along the external circuit. The longer the length of the pipes, bends, turns, the less profitable the HP. The optimal distance from the house to the shore is 100 m. It can be extended by 25% by increasing the diameter of the collector pipes from 32 to 40 mm.
Air - split and mono
It is more profitable to use air HP in the southern regions, where the temperature rarely drops below 0 °C, but modern equipment is able to operate at -25 °C. Most often, split systems are installed, consisting of indoor and outdoor units. The external set consists of a fan that blows over the radiator grill, the internal one consists of a condenser heat exchanger and a compressor.
The design of split systems provides for reversible switching of operating modes using a valve. In winter, the outdoor unit is a heat generator, and in summer, on the contrary, it gives it to the outside air, working as an air conditioner. Air VTs are characterized by extremely simple installation of the external unit.
Other benefits:
- The high efficiency of the outdoor unit is ensured by the large heat exchange area of the evaporator grille.
- Uninterrupted operation is possible at outdoor temperatures down to -25 °C.
- The fan is located outside the room, so the noise level is within acceptable limits.
- In summer, the split system works like an air conditioner.
- The set temperature indoors is automatically maintained.
When designing the heating of buildings located in regions with long and frosty winters, it is necessary to take into account the low efficiency of air HPs at low temperatures. For 1 kW of electricity consumed, there is 1.5–2 kW of heat. Therefore, it is necessary to provide additional sources of heat supply.
The simplest installation of the HP is possible in the case of monoblock systems. Only tubes with coolant go inside the room, and all other mechanisms are located outside in one case. This design significantly increases the reliability of the equipment, and also reduces noise to less than 35 dB - this is at the level of a normal conversation between two people.
When installing a pump is uneconomical
It is almost impossible to find vacant plots of land in the city for the location of the external contour of a ground-to-water HP. It is easier to install an air source heat pump on the outer wall of the building, which is especially advantageous in southern regions. For colder areas with prolonged frosts, there is a possibility of icing on the external radiator grille of the split system.
The high efficiency of the HP is ensured under the following conditions:
- The heated room must have insulated external enclosing structures. The maximum heat loss cannot exceed 100 W/m 2 .
- HP is able to work effectively only with inertial low-temperature "warm floor" system.
- In the northern regions, HP should be used in conjunction with additional heat sources.
When the outdoor temperature drops sharply, the inertial circuit of the “warm floor” simply does not have time to warm up the room. This is often the case in winter. In the afternoon the sun warmed up, on the thermometer -5 ° C. At night, the temperature can quickly drop to -15 ° C, and if a strong wind blows, the frost will be even stronger.
Then it is necessary to install ordinary batteries under the windows and along the outer walls. But the temperature of the coolant in them should be twice as high as in the "warm floor" circuit. Additional energy in a country cottage can be provided by a fireplace with a water circuit, and an electric boiler in a city apartment.
It remains only to determine whether the HP will be the main or supplementary heat source. In the first case, it must compensate for 70% of the total heat loss of the room, and in the second - 30%.
Video
The video provides a visual comparison of the advantages and disadvantages of various types of heat pumps, explains in detail the design of the air-to-water system.
Evgeny AfanasievChief Editor
Publication author 05.02.2019
The heat pump itself is an original station. Its task is to take energy from the environment. In the future, such a technique converts the received heat and can be used to ensure comfort in the house. Sometimes such a pump works as a "climate control", it can give heat or cool the house. In addition, a device for providing hot water is actively used. Let us consider in more detail what a heat pump is for heating a house, prices, its types and how it is used.
Read in the article:
What are heat pumps for home heating: how they work
The heat pump is an economical heating device. It does not require fuel and requires virtually no energy to operate. All the warmth that further makes the house as comfortable as possible comes from the environment.
Note! This is a rational solution that allows you to significantly reduce funds during the heating season.
Such pumps can be safely used, this is a completely environmentally friendly and safe technique.
The principle of operation of the device
Thanks to the refrigerant, this system functions. It accumulates heat and releases it over time if necessary.
The principle of energy transfer works, a similar method can be observed in any conventional refrigerator. However, in this case, it is not cold that accumulates, but heat. This is a great opportunity to provide a comfortable temperature in the house with a minimum amount of resources, because you do not need to use any fuel.
HP advantage
Modern technology has many advantageous features, including cost-effectiveness of use:
| Advantages | Description |
|---|---|
 Efficiency | The heat pump needs electricity to operate. However, as a result, during the conversion into thermal energy, it increases by 2.5-5 times. This allows for economical consumption to provide the maximum amount of heat. |
 autonomy | The system works without any additional communications. It is enough to install the TN correctly. Only electricity is used. It can be obtained from the generator if there are no central networks. |
 Versatility | Such equipment is used not only for heating private houses, but also for public places. The pump is relevant even in industry, if we are talking about fairly large objects. |
 Environmental friendliness | The operation of such a heating system does not harm nature at all. |
 Durability | Such a device has been operating for several decades. The service life is defined as 50 years, and then it will be possible to make major repairs and continue to use the pump. |
 Safety | Often the heating system in private homes is really very dangerous. It depends on what combustible substances are used. It can be gas, fuel, coal. When using the pump, there are no additional combustible substances, in addition, it does not heat up to too high temperatures, and a fire cannot occur. |
 Comfortable use | The pump works silently, it provides a certain level of heat and humidity in the house, so that it will always be comfortable to be in the premises. Moreover, there is the possibility of remote control, if you need to adjust the temperature. |
Note! Such positive characteristics make it possible to safely call the heat pump the most modern way of heating.
Types of TN
Pumps can be varied depending on how they take heat. Sources can be different, and the name corresponds to where the technique takes heat from.
Heat pumps are divided into:
- Geothermal.
- Air.
- secondary heat.
geothermal model
This version of the pump uses the environment. In particular, it is land and water. Different waters can be used, both underground and surface. There are vertical and horizontal designs.
Under them, a certain ditch is specially dug in the soil. It should be lower than the depth of freezing of the soil. Usually it is enough to go down 1.2 meters. Usually, if there is a place for digging such a trench, then a horizontal structure is chosen.
The vertical model is suitable for more compact areas. Not much space is needed here. In addition, even owners of large plots may refuse to dig a ditch due to a violation of landscape design. When there is a reservoir nearby, the HP is installed in it, this applies to rivers and lakes.
This solution is the least expensive, however, it is only suitable for houses near a pond. It will be necessary to take into account many details regarding the reservoir itself.
All pumps are further subdivided into open and closed types. The main difference is that in the first case, the water returns back to the ground or a reservoir after the cycle ends.
Geothermal heat pumps for home heating, connection prices:
- the equipment itself - ≈ $ 7,500;
- system installation - ≈ $ 7,500;
- various costs for providing heat - ≈ $ 500 per year.
Heat pump for home heating price for a horizontal collector:
- the equipment itself - ≈ $ 7,500;
- system installation - ≈ $ 3,700;
- various costs for providing heat - ≈ $ 560 per year.
Air system
The effect of this technique is easiest to compare with conventional air conditioning. However, the air pump must be an order of magnitude more powerful. This is due to the need for a large temperature difference between the house and the street.
A simple air conditioner does not allow such heating, and in such a situation it is worth noting that the pump helps to completely remove the radiators. Old batteries are now completely recycled.
Expert opinion
HVAC design engineer (heating, ventilation and air conditioning) LLC "ASP North-West"
Ask a specialist“There is a significant drawback that at a temperature outside of -15 ° C, it is difficult for such a pump to cope with its duties. You have to take a lot of heat from the environment for normal transformation. But most often already at -5 ° C, this equipment ceases to work effectively.”
Secondary heat
These pumping stations are actively used when there is already a heat source and a central heating pipeline in the house.
Advice! However, for a private house, this may not be rational, because you will have to support the operation of two systems.
In turn, the industry always lacks simple central heating, the pump can easily supplement it and provide even a large enterprise with the necessary amount of heat.
There are several types of pumps from this category:
- Air-to-air.
- Air-water.
- Earth-water.
- Heat pump for water-to-water heating of the house, as heat conversion is planned.
Operation of an air-to-air heat pump equipment and installation price
In this case, the pump accumulates energy simply from atmospheric air. One part of the equipment is mounted outside the building. In turn, the refrigerant then transfers energy to the condenser.
The last part is installed already indoors. Warm warm air comes out, it allows you to make the room comfortable.
Note! Unfortunately, this option is not suitable for winter, when heating is especially needed. When the air is very cold, even modern technology cannot convert it.
Air-to-air system cost:
- the equipment itself - ≈ $ 10,000;
- system installation - ≈ $ 620;
- various costs for providing heat - ≈ $ 750 per year.
Some craftsmen managed to build a heat pump for heating a house with their own hands from a refrigerator.
True, not a powerful unit, it is positioned with an air-to-air heating device and can be used to heat a small room or a greenhouse.
HP water-water
This technique is actively used in those places where there are reservoirs. These can be natural or artificial sources. At a certain depth, water bodies retain a certain amount of heat even in winter. That is why it is possible to take energy and transform it when located at a certain depth.
Note! An important condition is the option that the pump must be installed not in stagnant, but in running water.
This type of heat pump is very easy to install. It has excellent technical characteristics. This model is actively used.
Heat pump water-to-water system, turnkey price:
- the equipment itself - ≈ $ 7,500;
- system installation - ≈ $ 5,000;
- various costs for providing heat - ≈ $ 450 per year.
Advice! If there is no reservoir nearby, then the unit can be located in the place where a large amount of water passes in the ground soils.
Air water system
Such a unit is actively used for various purposes. It can operate at temperatures up to -15 degrees, but this simply will not be enough to ensure a comfortable temperature inside the house.
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