What are heat pumps for heating a home? Water-to-water heat pumps: device, principle of operation, installation and calculation rules. Some nuances of operation

A heat pump is a device that can provide your home with heating in the winter, cooling in the summer, and hot water production all year round.

A heat pump uses energy from renewable sources - heated air, earth, rock or water - to produce thermal energy. This transformation is carried out with the help of special substances -.

Operating principle of a heat pump

Structurally, any heat pump consists of two parts: an external one, which “takes” heat from renewable sources, and an internal one, which transfers this heat to the heating or air conditioning system of your home. Modern heat pumps are highly energy efficient, which in practical terms means the following - the consumer, i.e. A homeowner using a heat pump spends, on average, only a quarter of the money he would spend on heating or cooling his home as if he did not have a heat pump.

In other words, in a system with a heat pump, 75% of useful heat (or cold) is provided from free sources - the heat of the earth, groundwater, or used air heated in the premises and discharged outside.

Let's look at how perhaps the most popular heat pump in everyday life works, powered by the heat of the earth. The heat pump operates in several cycles.

Cycle 1, evaporation

The outer part of the “earth” heat pump is a closed system of pipes buried in the ground to a certain depth, where the temperature is stable all year round and is 7-12°C. To “collect” a sufficient amount of earth’s energy, it is required that the total area occupied by the underground pipe system be 1.5-2 times larger than the entire heated area of ​​the house. These pipes are filled with refrigerant, which is heated to the temperature of the ground.

The refrigerant has a very low boiling point, so it can go into a gaseous state already at ground temperature. This gas then enters.

Cycle 2, compression

It is this compressor that consumes all the energy necessary for the operation of the heat pump, but compared, for example, with heating from, these costs are noticeably lower. We'll come back to cost comparisons later.

So, gaseous refrigerant heated to a temperature of 7-12°C from underground pipes in the compressor chamber is strongly compressed, which leads to its sharp heating. To understand this, just think about how hot a regular bicycle pump gets when you inflate your tires. The principle is the same.

Note to the owner

"Heat pump - modern heating. But the actual efficiency values ​​of heat pumps depend on temperature conditions, i.e. on cold days their effectiveness decreases. It is about 150% at a temperature of −20 °C, and about 300% at a source temperature of +7 °C.”

Cycle 3, condensation

After the compression cycle, we received hot steam under high pressure, which is supplied to the internal, “home” part of the heat pump. Now this gas can be used for an air heating system or for heating water in a water heating and hot water supply system. This hot steam can also be used with the "" system.

By releasing heat into the heating system, the hot gas cools, condenses and turns into liquid.

Cycle 4, expansion

This fluid enters the expansion valve, where its pressure is reduced. The low pressure liquid refrigerant is now sent back to underground part to heat up to ground temperature. And all the cycles repeat.

Efficiency of heat pumps

For every 1 kW of electricity consumed by a heat pump to operate its compressor, on average, about 4 kW of useful thermal energy is generated. This corresponds to 300% efficiency.

Comparison of heating using a heat pump with other methods.

Data provided by the European Heat Pump Association (EHPA)

Heating type	Energy efficiency, %

Please understand that heat pump efficiency varies depending on the specific conditions in which your unit operates. So, if you are using a ground source heat pump and you have clay soil on your property, the efficiency of the heat pump will be approximately twice as high as if the heat pump pipes were in sandy soil.

It should also be remembered that the laying of the underground part should be carried out below the freezing mark of the soil. Otherwise, the heat pump will not work at all.

The actual efficiency values ​​of heat pumps depend on temperature conditions, i.e. on cold days their effectiveness decreases. It is about 150% at a temperature of −20 °C, and about 300% at a source temperature of +7 °C. But technology does not stand still - modern models is more energy efficient, and this trend continues.

Heat pumps for home cooling

In terms of its operating principle, a heat pump is similar to or. Therefore, in the summer it can be used not for heating the house, but for cooling or air conditioning. Let's remember what if we're talking about about an “earthen” heat pump, the ground temperature is stable within 7-12°C all year round. And with the help of a heat pump it can be transferred to the premises of the house.

The principle of operation of a cooling system using a heat pump is similar to a heating system, only instead of radiators it is used. With passive cooling, the coolant simply circulates between the fan coils and the well, i.e. the cold from the well directly enters the air conditioning system, but the compressor itself does not work. If passive cooling is not enough, the heat pump compressor is turned on, which additionally cools the coolant.

Types of Heat Pumps

Household heat pumps come in 3 main types, differing in the external heat source:

• “earth” or “ground-water”, “ground-air”;
• “water” or “water-water”, “water-air”;
• “air” or “air-to-water”, “air-to-air”.

Ground source heat pumps

The most popular are heat pumps that use the heat of the earth. They have already been discussed above. These are the most effective, but also the most expensive of all types. Pipes going underground can be located vertically or horizontally. Depending on this, “ground” heat pumps are divided into vertical And horizontal.

Vertical heat pumps require immersion of pipes through which the refrigerant circulates to a considerable depth: 50-200 m. True, there is an alternative - to make not one such well, but several, but smaller ones. The distance between such wells must be at least 10 m. To calculate the drilling depth, you can roughly estimate that a 10 kW heat pump will require wells (one or more) with a total depth of about 170 m. It should also be remembered that it is useless to drill very shallow ones - less than 50 m - wells.

At horizontal laying expensive drilling to great depths is not required. The depth of laying pipelines with this method is about 1 m; depending on the region of installation, this value can either decrease or increase. With this method, the pipe with the refrigerant is laid so that the distance between adjacent sections is at least one and a half meters, otherwise heat collection is not effective.

Note to the owner

“If you live in a temperate climate zone - for example, in the North-West - then the most effective option for you - a heat pump that uses the heat of the earth. Moreover, it is better to install a vertical version of the heat pump - especially if your house is located on rocky rocks.”

To install a 10 kW heat pump, you need a total length of buried pipe of about 350-450 m. If you take into account the restrictions associated with the proximity of different areas to each other, then you will need a plot of land with dimensions of 20 by 20 meters. Whether such a free plot is available is a big question.

How to choose the right heat pump

If you live in a temperate climate zone - for example, in the Northwest - then the most effective option for you is a heat pump that uses the heat of the earth. Moreover, it is better to install a vertical version of the heat pump - especially if your house is located on rocky rocks, where finding a free vast plot of land is problematic. But this type of heat pump is the most expensive in terms of capital costs.

In an area with a mild climate - for example, in Sochi - you can install an air-to-water heat pump, which does not require excessive capital costs and is especially effective in areas where seasonal temperature fluctuations are relatively small.

Depending on the principle of operation, there are also. Models powered by electricity are more popular.

One more important note. A good idea is combined heat pump models that combine the classic version of a heat pump with a gas or electric heater. Such heaters can be used in adverse weather conditions when the efficiency of the heat pump is reduced. As already mentioned, a particularly low efficiency is typical for air-to-water and air-to-air heat pumps.

The combination of these two heat sources allows to reduce the cost of capital expenditures and increase the payback period of the heat pump installation.

Advantages and disadvantages of heat pumps

The main advantage of heat pumps is their low operating costs. Those. The cost of the heat or cooling produced to the end user is the lowest compared to other heating/air conditioning methods. In addition, a heat pump system is practically safe for the home. Consequently, the requirements for the ventilation systems of its premises are simplified and the level of fire safety. Which also has a positive effect on the cost of installing these systems.

Heat pumps are easy to use and very reliable, and are also practically silent.

Another plus is that you can easily switch the heat pump from heating to cooling if necessary. You just need to have not only heating systems at home, but also fan coil units.

What is a heat pump for a home ✮Large selection of heat pumps on the website portal

But they also have disadvantages, the main one of which is the flip side of the main advantage - the capital costs of their installation are very significant. Until recently, another disadvantage of heat pumps was the relatively low temperature of the coolant - no more than 60 C. But recent developments have made it possible to eliminate this disadvantage. True, the price for such models is higher than for standard ones.

Heating equipment, which uses quite expensive types of energy carriers such as gas, electricity, solid and liquid fuels, has relatively recently had a worthy alternative - a water-to-water heat pump. For the operation of such equipment, which is just beginning to gain popularity in Russia, inexhaustible energy sources characterized by low potential are needed. In this case, thermal energy can be extracted from almost any water source, which can be natural and artificial reservoirs, wells, wells, etc. If the calculation and installation of such a pumping installation is carried out correctly, then it is capable of providing heating for both residential and industrial buildings throughout the winter period.

Structural elements and operating principle

The principle of operation of the heat pumps under consideration for heating a house resembles the principle of operation of refrigeration equipment, only in reverse. If a refrigeration unit removes some of the heat from its internal chamber to the outside, thereby lowering its temperature, then the work of the heat pump is to cool the environment and heat the coolant that moves through the pipes of the heating system. Air-water and ground-water heat pumps operate on the same principle, which also use energy from low-potential sources to heat residential and industrial premises.

The design diagram of a water-to-water heat pump, which is the most productive among devices using low-potential energy sources, assumes the presence of such elements as:

• an external circuit along which water moves, pumped from a water source;
• an internal circuit through which the refrigerant moves through the pipeline;
• an evaporator in which the refrigerant is converted into gas;
• a condenser in which the gaseous refrigerant becomes a liquid again;
• a compressor designed to increase the pressure of a refrigerant gas before it enters the condenser.

Thus, there is nothing complicated in the design of a water-to-water heat pump. If there is a natural or artificial reservoir near the house, then to heat the building it is best to use a water-to-water heat pump, the operating principle and design features of which are as follows.

1. The circuit, which is the primary heat exchanger through which antifreeze circulates, is located at the bottom of the reservoir. In this case, the depth at which the primary heat exchanger is installed must be below the freezing level of the reservoir. Antifreeze, passing through the primary circuit, is heated to a temperature of 6–8°, and then supplied to the heat exchanger, giving off heat to its walls. The task of antifreeze circulating through the primary circuit is to transfer the heat energy of water to the refrigerant (freon).
2. In the event that the heat pump operation scheme involves the intake and transfer of thermal energy from water pumped from an underground well, the antifreeze circuit is not used. Water from the well is passed through a special pipe through the heat exchanger chamber, where it transfers its thermal energy to the refrigerant.
3. The heat exchanger for heat pumps is the most important element of their design. This is a device consisting of two modules - an evaporator and a condenser. In the evaporator, freon, supplied through a capillary tube, begins to expand and turns into gas. When gaseous freon comes into contact with the walls of the heat exchanger, low-grade thermal energy is transferred to the refrigerant. Freon charged with such energy is supplied to the compressor.
4. The compressor compresses freon gas, causing the temperature of the refrigerant to increase. After compression in the compressor chamber, the freon enters another module of the heat exchanger - the condenser.
5. In the condenser, gaseous freon again turns into liquid, and the thermal energy accumulated by it is transferred to the walls of the container in which the coolant is located. Entering the chamber of the second heat exchanger module, freon, which is in a gaseous state, condenses on the walls of the storage tank, imparts thermal energy to them, which is then transferred to the water located in such a chamber. If, at the exit of the evaporator, freon has a temperature of 6–8 degrees Celsius, then at the entrance to the condenser of a water-to-water heat pump, thanks to the above-described principle of operation of such a device, its value reaches 40–70 degrees Celsius.

Thus, the principle of operation of a heat pump is based on the fact that the refrigerant, when transitioning into a gaseous state, takes thermal energy from water, and when transitioning to a liquid state in the condenser, it releases the accumulated energy to the liquid medium - the coolant of the heating system.

Air-water and ground-water heat pumps operate on exactly the same principle; the only difference is in the type of source used to produce low-potential thermal energy. In other words, the heat pump has one operating principle that does not vary depending on the type or model of the device.

How effectively the heat pump heats the heating system coolant is largely determined by fluctuations in the temperature of the water, a source of low-potential energy. Such devices demonstrate high efficiency when working with water from wells, where the temperature of the liquid medium throughout the year is in the range of 7–12 degrees Celsius.

The water-to-water pump is one of the ground-based types of heat pumps

The operating principle of a water-to-water heat pump, which ensures the high efficiency of this equipment, allows the use of such devices to equip heating systems of residential and industrial buildings not only in regions with warm winters, but also in the northern regions.

In order for the heat pump, the operation scheme of which is described above, to demonstrate high efficiency, you should know how to choose the right equipment. It is highly advisable that the selection of a water-to-water heat pump (as well as “air-to-water” and “earth-to-water”) is carried out with the participation of a qualified and experienced specialist.

When choosing a heat pump for water heating, the following parameters of such equipment are taken into account:

• productivity, which determines the area of ​​the building the heating of which the pump can provide;
• the brand name under which the equipment is manufactured (this parameter must be taken into account because serious companies, whose products have already been appreciated by many consumers, pay serious attention to both the reliability and functionality of the models they produce);
• the cost of both the selected equipment and its installation.

When choosing heat pumps water-to-water, air-to-water, earth-to-water, it is recommended to pay attention to the availability of additional options for such equipment. This includes, in particular, the following opportunities:

• control the operation of equipment in automatic mode (heat pumps operating in this mode due to a special controller make it possible to create comfortable living conditions in the building they serve; changing operating parameters and other actions to control heat pumps that are equipped with a controller can be performed using mobile device or remote control);
• using equipment for heating water in a hot water supply system (pay attention to this option because in some (especially old) models of heat pumps, the collector of which is installed in open reservoirs, it is not available).

Calculation of equipment power: implementation rules

Before you begin choosing a specific heat pump model, you need to develop a design for the heating system that such equipment will serve, as well as calculate its power. Such calculations are necessary in order to determine the actual thermal energy demand of a building with certain parameters. In this case, it is necessary to take into account the heat losses in such a building, as well as the presence of a hot water supply circuit in it.

For a water-to-water heat pump, power calculation is performed using the following method.

• First, determine the total area of ​​the building for heating which the purchased heat pump will be used.
• Having determined the area of ​​the building, you can calculate the power of the heat pump capable of providing heating. When performing this calculation, they adhere to the following rule: for 10 sq. m of building area requires 0.7 kilowatts of heat pump power.
• If the heat pump will also be used to ensure the functioning of the domestic hot water system, then 15–20% is added to the obtained value of its power.

Calculation of heat pump power performed using the above described method is relevant for buildings in which the ceiling height does not exceed 2.7 meters. More accurate calculations that take into account all the features of buildings that are to be heated using a heat pump are performed by employees of specialized organizations.

For an air-water heat pump, the power calculation is performed using a similar method, but taking into account some nuances.

How to make a heat pump yourself

Having a good understanding of how a water-to-water heat pump works, you can make such a device with your own hands. In fact, a homemade heat pump is a set of ready-made technical devices, correctly selected and connected in a certain sequence. In order for a home-made heat pump to demonstrate high efficiency and not cause problems during operation, it is necessary to perform a preliminary calculation of its main parameters. To do this, you can use the appropriate programs and online calculators on the websites of manufacturers of such equipment or contact specialized specialists.

So, in order to make a heat pump with your own hands, you need to select its equipment elements according to pre-calculated parameters and perform their correct installation.

Compressor

A compressor for a heat pump made by yourself can be taken from an old refrigerator or split system, paying attention to the power of such a device. The advantage of using compressors from split systems is the low noise level created during their operation.

Capacitor

As a condenser for a homemade heat pump, you can use a coil dismantled from an old refrigerator. Some people make it themselves using plumbing or a special refrigeration pipe. As a container in which to place the condenser coil, you can take a stainless steel tank with a volume of approximately 120 liters. To place a coil in such a tank, it is first cut into two halves, and then, when the installation of the coil is completed, it is welded.

It is very important to calculate its area before choosing or making your own coil. To do this you need the following formula:

P3 = MT/0.8PT

The parameters used in this formula are:

• MT – power of heat generated by the heat pump (kW);
• PT is the difference between the temperatures at the inlet to the heat pump and at the outlet.

To prevent air bubbles from being created in the heat pump condenser from the refrigerator, the inlet to the coil should be located in the upper part of the tank, and the outlet from it should be located in the lower part.

Evaporator

As a container for the evaporator, you can use a simple plastic barrel with a capacity of 127 liters with a wide neck. To create a coil, the area of ​​which is determined in the same way as for a condenser, a copper tube is also used. Home-made heat pumps typically use submersible evaporators, into which liquefied freon enters from below and turns into gas at the top of the coil.

When making a heat pump yourself, you should install the thermostat very carefully using soldering, since this element cannot be heated to a temperature exceeding 100 degrees Celsius.

To supply water to the elements of a self-made heat pump, as well as to drain it, ordinary sewer pipes are used.

Water-to-water heat pumps, when compared with air-to-water and ground-to-water devices, are simpler in design, but at the same time more efficient, which is why equipment of this type is most often manufactured independently.

Assembling a homemade heat pump and putting it into operation

To assemble and put into operation a homemade heat pump, you will need the following consumables and equipment:

1. welding machine;
2. vacuum pump (to test the entire system for vacuum);
3. a cylinder with freon, refilling of which is carried out through a special valve (the installation of the valve in the system should be provided for in advance);
4. temperature sensors that are installed on capillary pipes at the outlet of the entire system and at the outlet of the evaporator;
5. starting relay, fuse, DIN rail and electrical panel.

All welding and threaded connections during assembly should be performed with the highest quality possible to ensure absolute tightness of the system through which freon will move.

In the event that water in an open reservoir acts as a source of low-potential energy, it is additionally necessary to manufacture a collector, the presence of which presupposes the operating principle of heat pumps of this type. If it is intended to use water from an underground source, it is necessary to drill two wells, into one of which the water will be discharged after it has passed through the entire system.

1, average rating: 5,00 out of 5)

Reading time: 7 minutes.

The term heat pump means a set of units designed to accumulate heat energy from various sources in the environment and transfer this energy to consumers.

For example, such sources can be sewer risers, waste from various large industries, heat generated during operation from various power plants, etc. As a result, the source can be various environments and bodies with a temperature of more than one degree.

The purpose of a heat pump is to convert the natural energy of water, earth or air into thermal energy for the needs of the consumer. Since these types of energy are constantly self-regenerating, they can be considered a limitless source.

Heat pump for heating a house operating principle

The operating principle of heat pumps is based on the ability of bodies and media to transfer their thermal energy to other similar bodies and media. Based on this feature they distinguish various types heat pumps, in which there must be an energy supplier and its recipient.

In the name of the pump, the source of thermal energy is indicated in the first place, and the type of medium to which the energy is transferred is indicated in the second place.

There are 4 main elements in the design of each home heating heat pump:

1. A compressor designed to increase the pressure and temperature of steam resulting from boiling freon.
2. An evaporator, which is a tank in which freon is liquid state turns into gas.
3. In the condenser, the refrigerant transfers thermal energy to the internal circuit.
4. The throttle valve controls the amount of refrigerant entering the evaporator.

The air-air type of heat pump means that thermal energy will be taken from the external environment (atmosphere) and transferred to the carrier, also to the air.

Air-to-air heat pump: operating principle

The principle of operation of this system is based on the following physical phenomenon: a medium in a liquid state, evaporating, lowers the temperature of the surface from where it dissipates.

For clarity, let’s briefly consider the operation diagram of the refrigerator freezer. Freon circulating through the refrigerator tubes takes heat from the refrigerator and itself heats up. Subsequently, the heat collected by it is transferred to the external environment (that is, to the room in which the refrigerator is located). Then the refrigerant, compressed in the compressor, cools again and the cycle continues. An air source heat pump works on the same principle - it takes heat from the street air and heats the house.

The design of the unit consists of the following parts:

• The external pump unit consists of a compressor, an evaporator with a fan and an expansion valve.
• Thermally insulated copper tubes serve for circulation of freon
• A capacitor with a fan located on it. Serves to disperse already heated air over the area of ​​the premises.

When an air source heat pump operates when heating a house, the following processes occur in a certain order:

• By means of a fan, air from the street is drawn into the device and passes through the external evaporator. Freon circulating in the system collects all the heat energy from the street air. As a result, it changes from a liquid state to a gaseous state.
• Subsequently, gaseous freon is compressed in the condenser and passes into the indoor unit.
• The gas then turns into a liquid state, releasing the accumulated heat to the air in the room. This process occurs in a condenser located indoors.
• Excess pressure goes through the expansion valve, and freon in a liquid state goes to a new circle.

Freon will constantly take thermal energy from the street air, since its temperature will always be lower. The exception is when on the street severe frosts. Under such conditions, the efficiency of the heat pump will decrease.

To increase the power of the unit, the surfaces of the condenser and evaporator are maximized.

Like every complex device, an air source heat pump has its pros and cons. Among the advantages it is worth highlighting:

1. Depending on the need, the unit can increase or decrease the heating temperature of the house.
2. This type of pump does not pollute the environment harmful products fuel combustion.
3. The device is easy to install.
4. The air pump is absolutely safe in terms of fire.
5. The heat transfer coefficient of the pump is very high compared to energy costs (per 1 kW of consumed electricity accounts for 4 to 5 kW of heat generated)
6. They have an affordable price.
7. The device is convenient to use.
8. The system is controlled automatically.

The disadvantages of the air system are worth mentioning:

1. Slight noise generated when the device is operating.
2. The effectiveness of the device depends on the temperature environment.
3. At low outside temperatures, electricity consumption increases. (below -10 degrees)
4. The system is entirely dependent on the availability of electricity. The problem can be solved by installing an autonomous generator.
5. The air pump cannot heat water.

In general, air-to-air devices are ideal for heating wooden houses, which, due to the nature of the material, have reduced natural heat loss.

Before choosing an air pump, you should find out the following key points:

• Indicator of thermal insulation of premises.
• Squaring of all rooms
• Number of people living in a private house
• Climate conditions

In most cases, 10 sq. m of room should account for about 0.7 kW of device power.

Heat pumps for home heating water water.

When installing a heating system in a private home, water-to-water systems are well suited. In addition, they will be able to provide the home with hot water. Various reservoirs, groundwater, etc. are suitable as sources of natural heat.

The operation of the water-water pump is based on the law that a change in the state of aggregation (from liquid to gas and vice versa) of a substance, under the influence of various factors, entails the release or absorption of heat energy.

This type of pump can be used to heat a house even at low ambient temperatures, since positive temperatures are still maintained in the deep layers of the earth.

The operating principle of a water-water heat pump is as follows:

• A special pump drives water through the copper pipes of the system from external source into the installation.
• In the device, water from the environment acts on the refrigerant (freon), the boiling point of which is from +2 to +3 degrees. Part of the heat energy of the water is transferred to freon.
• The compressor draws in refrigerant gas and compresses it. As a result of this process, the temperature of the refrigerant increases even more.
• Then the freon is sent to the condenser, where it heats the water to the required temperature (40-80 degrees). The heated water enters the heating system pipeline. Here the freon returns to a liquid state and the cycle begins again.

It is worth noting that water-water appliances are used to heat a house with an area of ​​50-150 sq.m.

Heat pump water water: operating principle

When choosing a device of this class, you should pay attention to certain conditions:

• As an energy source, preference should be given to open reservoirs (it is easier to install pipes), at a distance of no more than 100 m. In addition, the depth of the reservoir for more northern regions should be at least 3 meters (at this depth the water usually does not freeze). Pipes supplied to water must be insulated.
• Water hardness greatly affects the operation of the pump. Not every model is capable of functioning with high rates rigidity. As a result, before purchasing the device, a water sample is taken and a pump is selected based on the results obtained.
• Based on the type of operation, the units are divided into monovalent and bivalent. The former will do an excellent job as the main heat source (due to their high power). The latter can act as an additional source of heating.
• As the power of the pump increases, its efficiency increases, but at the same time, electricity consumption also increases.
• Additional features of the device. For example: sound-insulated housing, domestic water heating function, automatic control, etc.
• To calculate the required power of the device, you need to multiply the total area of ​​the premises by 0.07 kW (energy indicator per 1 sq.m.). This formula is valid for standard rooms with a height of no more than 2.7 m.

Heat pumps are becoming increasingly popular. With the help of these devices you can heat (cool) houses and organize hot water supply, saving significant money.

It is quite difficult for people far from physics to understand the principle of operation of heat pumps, and therefore many misconceptions are being 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 has acquired.

Pros

We know from school that under normal conditions a colder substance cannot give up its heat to a hotter one, but on the contrary, it is heated by it until their temperatures are equal. This is the holy truth. But the heat pump creates such conditions that the colder environment begins to give up its heat to the warmer one, thereby cooling even more.

The simplest, tired example of a heat pump is a refrigerator. In it, heat is pumped from a colder chamber into a warmer kitchen area. At the same time, the freezer cools even more, and the kitchen heats up even more from the radiator located on the rear panel of the refrigerator.

The operating principle of most heat pumps is based on the properties of intermediate coolants (gases, most often freons) that are used in these machines. It is freons that are the intermediary that allows you to take heat from a colder body, giving it to a hotter one.

You've probably 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, gas heats up. Keeping this in mind, it will not be at all difficult for you to understand the principle of operation of a heat pump, simplest scheme which is shown in the figure.

Heat pump components

The simplest heat pump consists of four important components:

• evaporator;
• capacitor;
• compressor;
• capillary.

The compressor compresses the freon into a liquid state in the condenser, which heats up. It is this heat that can be used in heating or 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 cools, giving off heat during heat exchange to heating radiators or heated floor pipes, and begins to condense. Passing through the capillary into the evaporator, the freon again becomes gaseous, while cooling the evaporator (remember the frost on the can?).

In order for the process not to stop, you need to constantly supply heat to the evaporator, otherwise the freon there will simply stop evaporating, because the temperature of the evaporator is at permanent job the compressor may drop significantly. 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.

Let's say the temperature of freon evaporation is minus sixty degrees Celsius, and we blow frosty street air onto the evaporator, with a temperature of minus thirty - freon, naturally, will evaporate, taking away 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 unscrupulous “sellers” use 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 the cheapest oil heater. People simply often confuse efficiency and the so-called COP.

COP is more of an economic coefficient 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. KOP 5 - this simply means that to pump 5 kW of free heat from the street to the house, we spent 1 kW of paid electricity. It’s just that the COP does not take into account free thermal energy from the street, but only counts what was received as a result and what was spent for it.

Another myth is also related to the COP: in the passports of heat pumps and on sellers’ price tags, a single COP value is proudly indicated, which simply misleads buyers. The fact is that the COP of heat pumps is a variable value, not a constant one. And many unscrupulous businessmen are silent about this, because they indicate the COP for the most favorable conditions, when it is almost maximum. And this is much more dangerous than misconceptions about the efficiency being over-unity, because is fraught with real consequences.

Imagine that you believed that you would spend 1 kW of electricity to produce 5 kW of heat for the same heating in winter, because the heat pump data sheet states that COP = 5. We bought a heat pump with the required power, assembled a heating system... And at the most inopportune moment, when the frosts are the most severe, your heater consumes not 1 in 5, but 1 in 2 in the best case, or is not at all able to produce the necessary heat for heating. And then the understanding comes that it is possible to heat with this particular system only in the off-season... A very unpleasant situation - to give a lot of money and still heat with cheap oil radiators in cold weather, and only because you relied on the COP and stable, irreducible heat production.

And the heat production and COP of heat pumps is not constant. And this is due precisely to the inconsistent amount of heat supplied to the evaporator. For example, if you take heat for the evaporator from the air, then as the outside temperature drops, the COP also drops. At -30C outside, the COP of air heat pumps is almost equal to one, i.e. even a simple heating element will become more economical as a heater, not to mention the depreciation and increased wear of expensive equipment in such conditions. And the fall of the COP is not so bad. Often, some models of air source heat pumps are simply not able to produce the power necessary for heating when the outside temperature drops significantly.

Heat pumps that use the heat of the earth or water to heat the evaporator are also subject to a drop in productivity and COP, because During the heating season, they can freeze out the medium from which they pump heat, but such machines are more stable.

We will send the material to you by e-mail

Extracting heat from soil and water sources is not such an innovation. The Western world has long used geothermal energy for home heating. This topic is becoming more and more relevant as utility prices increase. A heat pump for heating a home makes it possible to warm the radiators in an environmentally friendly, safe and free manner.

The heat pump heats the house with natural heat

Heat pump for heating a house: principle of operation, advantages and disadvantages

An example of a device similar to a heat pump is found in every home - this is a refrigerator. It produces not only cold, but also heat - this is noticeable by the temperature of the rear wall of the unit. A similar principle is inherent in the heat pump - it collects thermal energy from water, earth and air.

Operating principle and device

The operating system of the device is as follows:

• water from a well or reservoir passes through the evaporator, where its temperature drops by five degrees;
• after cooling, the liquid enters the compressor;
• the compressor compresses the water, increasing its temperature;
• the heated liquid moves into the heat exchange chamber, where it transfers its heat to the heating system;
• the cooled water returns to the beginning of the cycle.

Heating systems based on heat pump units have three components:

• A probe is a coil located in water or ground. It collects heat and transfers it to the device.
• A heat pump is a device that extracts thermal energy.
• The heating system itself, including a heat exchange chamber.

Pros and cons of the device

First about positive aspects similar heating:

• Relatively low energy consumption. Only electricity is consumed for heating, and it will require much less than, for example, heating with electrical appliances. Heat pumps have a conversion factor that indicates the output of thermal energy relative to the electrical energy expended. For example, if the value of “ϕ” is 5, then for 1 kilowatt per hour of electricity consumption there will be 5 kilowatts of thermal energy.

• Versatility. This heating system can be installed in any location. This is especially true for remote areas where there are no gas mains. If it is not possible to connect electricity, the pump can run on a diesel or gasoline engine.
• Full automation. There is no need to add water to the system or monitor its operation.
• Environmental friendliness and safety. The heat pump system does not produce any waste or gases. The device cannot accidentally overheat.
• Such a unit can not only heat a house in winter at air temperatures down to minus fifteen degrees, but also cool it in summer. Such functions are available in reverse models.

• Long period of operation - up to half a century. The compressor may need to be replaced approximately every twenty years.

This system also has its drawbacks, which cannot be ignored:

• Prices. A heat pump for heating a home is not a cheap pleasure. This system will pay for itself no sooner than in five years.
• In areas where winter temperatures drop below fifteen degrees below zero, additional heat sources (electric or gas) will be required for the operation of the device.
• A system that takes thermal energy from the ground disrupts the ecosystem of the site. The damage is not significant, but this should be taken into account.

Expert's point of view

Andrey Starpovsky

Ask a question

“If you wish, you can make a heat pump for heating your home from a refrigerator with your own hands. But this will require certain technical knowledge.”

Which pump to choose

Installations differ in the source of thermal energy and the method of its transmission. There are five main types:

• Water-air.
• Ground-water.
• Air-to-air.
• Water-water.
• Air-water.

Site investigation

Before installing a heating system, it is important to examine the features of the site. This study will help determine which source of thermal energy will be the best option. The easiest way is if there is a pond near the house. This fact will free you from the need to carry out excavation work. Another practical solution is to use an area where the wind constantly blows. If there is neither one nor the other, you will have to stop at earthworks.

The heating system can have two installation options:

• using probes;
• with the installation of an underground collector.

Ground-water pump and installation options

Geothermal probes are usually installed in a small area that does not allow for a large pipeline to be installed. To install this system, you will need drilling equipment, since the depth of the wells must be at least one hundred meters and the diameter must be twenty centimeters. Probes are lowered into such wells. The number of wells affects the performance of the heating system.

If the area of ​​the site is large enough, you can do without drilling and install a horizontal system. For this purpose, the coil is buried to a depth of one and a half meters. This version of the system is considered the most stable and trouble-free.

Water-to-water pump: easy installation

A water-to-water heat pump for heating a house is suitable for areas with ponds. For the pipeline, you can use ordinary polyethylene pipes. The assembled collector is moved to the pond and lowered to the bottom there. This is one of the cheapest installation options that you can do yourself.

Air-to-air heat pump: installation cost

In an area where winds are constantly present, a system that uses air thermal energy is suitable. Installation in this case will also not require any special costs; you can do it yourself. You just need to install the pump no further than twenty meters from the house in the most ventilated place.

Heat pump for home heating: prices and manufacturers

Heat pump units on the Russian market are represented by products from the following companies: Vaillant (Germany), Nibe (Sweden), Danfoss (Denmark), Mitsubishi Electric (Japan), Mammoth (USA), Viessmann (Germany). Russian manufacturers SunDue and Henk are not inferior to them in quality.

For heating a house with an area of ​​100 square meters a ten-kilowatt installation will be required.

Table 1. Average cost different types 10 kilowatt pumps

Image	Pump type	Cost of equipment, rub	Cost of installation work, rub
	Ground-water Imported manufacturers	From 500,000	From 80 000
	Ground water domestic producers	From 360,000	From 70 000
	Air-water Imported manufacturers	From 270,000	From 50 000
	Air-water Domestic manufacturers	From 210,000	From 40 000
	Water-water imported manufacturers	From 230,000	From 50 000
	Water-water domestic producers	From 220,000	From 40 000

The turnkey price of a heat pump averages about 300 – 350 thousand rubles. The most budget-friendly option is the air-water system, since it does not require expensive excavation work.

Expert's point of view

Andrey Starpovsky

Head of the Heating, Ventilation and Air Conditioning Group, GRAST LLC

Ask a question