Efficient heat pump. The operating principle of heat pumps for heating a house. Is air heating available or planned in the future?

Paying for electricity and heating becomes more difficult every year. When building or purchasing a new home, the problem of economical energy supply becomes especially acute. Due to periodically recurring energy crises, it is more profitable to increase the initial costs of high-tech equipment in order to then receive heat at a minimal cost for decades.

The most cost-effective option in some cases is a heat pump for heating a home; the operating principle of this device is quite simple. It is impossible to pump heat in the literal 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. On the outside there is a radiator grille that is hot to the touch. From it, the heat collected inside the freezer is transferred to the room air.

The TN does the same thing, but in reverse order. The radiator grille, located on the outside of the building, is much larger in order to collect enough heat from the environment to heat the home. The coolant inside the radiator or manifold tubes transfers energy to the heating system inside the house and is then heated again outside the house.

Device

Providing heat to a home is a more complex technical task than cooling a small volume of a refrigerator where a compressor with freezing and radiator circuits is installed. The design of an air heat pump is almost as simple, it 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 installing 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, and a water-to-water heat pump provides 5–6 kW. TN can guarantee such a high coefficient of efficiency (efficiency).

Composition of pump components:

Home heating system, for which it is better to use heated floors.
Boiler for hot water supply.
A condenser that transfers energy collected externally to the indoor heating fluid.
An evaporator that takes energy from the coolant that circulates in the external circuit.
A compressor that pumps refrigerant from the evaporator, converting it from a gaseous to a liquid state, increasing the pressure and cooling it in the condenser.
An expansion valve is installed in front of the evaporator to regulate the refrigerant flow.
The outer contour is laid on the bottom of the reservoir, buried in trenches or lowered into wells. For air-to-air heat pumps, the circuit is an external radiator grille, blown by a fan.
Pumps pump coolant through pipes outside and inside the house.
Automation for control according to a given room heating program, which depends on changes in outside air temperature.

Inside the evaporator, the coolant of the external pipe register is cooled, giving off heat to the refrigerant of the compressor circuit, and then is pumped through the pipes at the bottom of the reservoir. There it heats up and the cycle repeats again. The condenser transfers heat to the cottage heating system.

Prices for different heat pump models

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 benefits of their works devoted to solving the problem of heating housing from alternative sources have appeared only in the last fifty years.

In the early seventies of the last century, the first global energy crisis occurred. The search for economical heating methods has led to the creation of devices capable of collecting energy from the environment, concentrating it and directing it to heat the house.

As a result, a HP design was developed with several thermodynamic processes interacting with each other:

When the refrigerant from the compressor circuit enters the evaporator, the pressure and temperature of the freon drops almost instantly. The resulting temperature difference contributes to the extraction 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 increased pressure it gives off heat to the in-house heating circuit. This phase is called isothermal compression.
When the freon passes through the choke, the pressure and temperature drop sharply. Adiabatic expansion occurs.

Heating the internal volume of a 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 outside air temperature.

Alternative fuel for pumps

There is no need to use carbon fuel in the form of firewood, coal, or gas to operate the HP. The source of energy is the heat of the planet scattered in the surrounding space, inside of which there is a constantly operating nuclear reactor.

The solid shell of continental plates floats on the surface of liquid hot magma. Sometimes it breaks out during volcanic eruptions. Near the volcanoes there are geothermal springs, where you can swim and sunbathe even in winter. A heat pump can collect energy almost anywhere.

To work with various sources of dissipated heat, there are several types of heat pumps:

"Air-to-air." 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.
"Ground-water". Heat collection pipes are located horizontally underground below the freezing level, so that even in the most severe frost they can 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 heated floors inside the house.

There is an option with an open external collector, when you can get by with two wells: one for collecting groundwater, and the second for draining back into the aquifer. This option is only possible if the quality of the liquid is good, 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 a drilled well quickly silts up or the water contains a lot of hardness salts, then stable operation of the HP is ensured by drilling more holes in the ground. The loops of the sealed outer contour are lowered into them. Then the wells are plugged using plugging made from a mixture of clay and sand.

Using dredge pumps

You can extract additional benefit from areas occupied by lawns or flower beds using ground-to-water HP. To do this, you need 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 completely remove the layer of earth at the installation site with a grader, lay the collector, and then fill the pit with an excavator. Shrubs and trees, whose roots can damage the external contour, should not be planted in this place.

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 sufficient to accommodate an external pipe register. Dry sandy soils do not provide sufficient heat flow. Then they use drilling wells up to 50 meters deep 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 increases. The temperature of the earth's interior increases by 3 degrees every 100 m. The efficiency of energy removal from a well reservoir can reach 50 W/m.

Installation and commissioning 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 significantly higher when compared with conventional gas heating equipment. Therefore, the payback period for initial costs extends over years. But a house is built to last for decades, and geothermal heat pumps are the most profitable heating method for country cottages.

Annual savings compared to:

gas boiler - 70%;
electric heating - 350%;
solid fuel boiler - 50%.

When calculating the payback period of a HP, it is worth taking into account the operating costs for the entire service 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 collector pipes at the bottom of a nearby reservoir. This does not require much professional knowledge, skills, or tools. It is enough to evenly distribute the coils of the coil over the surface of the water. There must be a distance between the turns of at least 30 cm, and a flooding depth of at least 3 m. Then you need to tie the weights to the pipes so that they go to the bottom. Substandard brick or natural stone are quite suitable here.

Installing a water-to-water HP collector will require significantly less time and money than digging trenches or drilling wells. The cost of purchasing pipes will also be minimal, since heat removal during convective heat exchange in an aquatic environment reaches 80 W/m. The obvious benefit of using HP is that there is no need to burn carbon fuel to produce heat.

An alternative method of heating a home is becoming increasingly popular, as it has several more advantages:

Environmentally friendly.
Uses a renewable energy source.
After commissioning is completed, there are no regular costs of consumables.
Automatically adjusts the heating inside the house based on the outside temperature.
The payback period for initial costs is 5–10 years.
You can connect a boiler for hot water supply to the cottage.
In summer it works like an air conditioner, cooling the supply air.
The service life of the equipment is more than 30 years.
Minimum energy consumption - generates up to 6 kW of heat using 1 kW of electricity.
Complete independence of heating and air conditioning of the cottage in the presence of an electric generator of any type.
Adaptation to the “smart home” system for remote control and additional energy savings is possible.

To operate a water-to-water HP, three independent systems are required: external, internal and compressor circuits. They are combined into one circuit by heat exchangers in which various coolants circulate.

When designing a power supply system, it should be taken into account that pumping coolant through the external circuit consumes electricity. The longer the length of the pipes, bends, and turns, the less profitable the VT. 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 can operate at -25 °C. Most often, split systems are installed, consisting of indoor and outdoor units. The external set consists of a fan blowing through the radiator grille, the internal set 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 external unit is a heat generator, and in summer, on the contrary, it releases it to the outside air, working like an air conditioner. Air heat pumps 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 radiator 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 inside the room 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 heaters at subzero temperatures. For 1 kW of consumed electricity there is 1.5–2 kW of heat. Therefore, it is necessary to provide additional sources of heat supply.

The simplest installation of VT is possible when using monoblock systems. Only the coolant pipes go inside the room, and all other mechanisms are located outside in one housing. 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 not cost-effective

It is almost impossible to find free 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 external wall of the building, which is especially beneficial in the southern regions. For colder areas with prolonged frosts, there is a possibility of icing of the external radiator grille of the split system.

High efficiency of HP is ensured if the following conditions are met:

The heated room must have insulated external enclosing structures. The maximum amount of heat loss cannot exceed 100 W/m2.
TN is able to work effectively only with an inertial low-temperature “warm floor” system.
In the northern regions, HP should be used in conjunction with additional heat sources.

When the outside air temperature drops sharply, the inertial circuit of the “warm floor” simply does not have time to warm up the room. This happens often in winter. During the day the sun was warm, the thermometer showed -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 you need to install regular 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. A fireplace with a water circuit can provide additional energy in a country cottage, and an electric boiler can provide additional energy 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 and explains in detail the structure of the air-water system.

Evgeniy AfanasyevChief Editor

Author of the publication 05.02.2019

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, the simplest diagram of 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?).

To ensure that the process does not stop, you need to constantly supply heat to the evaporator, otherwise the freon there will simply stop evaporating, because the temperature of the evaporator can drop significantly with 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.

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 with 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.

Today the entire civilized world is struggling to save energy resources. Of course, no one has yet succeeded in creating a perpetual motion machine, but an almost constant source of heat supply has already been found. This is our environment:

atmosphere;
the soil;
groundwater;
natural bodies of water.

The only question that remains is: how can heat be accumulated from the external environment and directed to internal needs?

For these purposes, a unit such as a heat pump is used. In fact, many technically educated people already know it - it is implemented in any modern refrigeration or climate control system.

Moreover, this unit works in the most direct way: in heating mode, they accumulate external atmospheric heat, transferring it to internal heat transfer devices - ventilated radiators.

It should be noted right away that using such a device will be effective for heating any isolated spaces with heat source temperature exceeding one degree Celsius.

The operating principle of this unit is fundamental on Carnot's law. It is based on accumulation of low-grade thermal energy by refrigerant with its subsequent transfer to the consumer.

The refrigerant, which has a lower temperature, is heated from external sources– soil, deep wells, natural reservoirs, while passing into a gaseous state of aggregation.
He forcibly compressed by the compressor, heating up even more, and again acquires a liquid state, releasing all the accumulated thermal energy in the heating radiators.
The cycle repeats– the liquid refrigerant again enters the external circuit of the system, where, evaporating, it is charged with thermal energy from external heat sources.

In this case, only the electricity necessary for compression and circulation of the refrigerant in the system is consumed, that is, heating of the interior is carried out in the most economical way.

Types of heat pumps

There are three main modifications of heat pumps:

- - "water - water";
  - "soil - water";
  - "air - water".

Water-to-water heat generators

Today, heat pump units are widely used in highly developed European countries. For example, in the Netherlands, entire cottage communities are heated using this heat exchange device, since there is an abundance of geothermal mines filled with water with a constant temperature of 32 degrees Celsius. And this is practically a free source of heat.

A similar variation of heat-generating
equipment is called “water - water”. This category includes any type of thermal systems using liquid media as sources of thermal energy.

Typically this operating principle is implemented as follows:

warm water from the well is supplied to the external, after which it is discharged into another well or into a nearby body of water.
The radiator is mounted at the bottom of an ice-free reservoir. It is made from stainless or metal-plastic pipe. Moreover, to save expensive refrigerant - freon - it is often used intermediate coolant circuit filled with “anti-freeze”- antifreeze or glycol solution (antifreeze).

The cost of water-to-water units varies widely and depends, first of all, on the heat generation capacity and the country of origin.

So, the lowest-power Russian-made unit, capable of developing thermal power about 6 kW, will cost almost $2000, and industrial two-compressor equipment with a power of more than 100 kW will cost almost thirty thousand dollars USA.

Air-water units

When using the atmosphere or sunlight as a source of thermal energy The heat pump is considered to be of the air-water class. In this case, a circulation fan is often installed on the external heat exchanger, which additionally pumps warm external air.

The cost of an 18-kilowatt air-heating apparatus of this class made in Russia starts at $5,000, and for twelve-kilowatt equipment from the Japanese company Fujitsu the consumer will have to pay almost $9,000.

Equipment of the "soil - water" class

There is also a variation that uses thermal energy source potential accumulated in the soil.
There are two types of such structures: vertical and horizontal.

Vertical— the layout of the heat collection collector is linear. All the system is placed in vertical trenches, the depth of which is 20...100 meters.
Horizontal- external manifold layouts, usually metal-plastic spirally twisted pipes, are laid in 2…4 meter horizontal trenches. And in this case, The greater the depth of the external heat sink, the better the heating “from the ground” works..

The price for units of the "soil - water" class is comparable to equipment of the same capacity of the "water - water" class and starts at two thousand US dollars for a six-kilowatt pump.

Pros and cons of a heating system based on a heat pump

The positive properties of heat pumps include:

Review: Last year I purchased a monoblock air-water heat pump for heating a country house. Expensive, of course, but I hope it will pay off in 10 years. The supplier installed the pump himself and connected it to the heating system, everything works practically without my participation. I'm happy with the choice.

The disadvantages of a heat pump include:

High installation cost. For normal operation of thermal equipment, it is necessary to make significant efforts - dig long trenches, lay deep wells, or often overcome significant distances to the nearest body of water.
The need for high-quality implementation of the system. The slightest leak of refrigerant or intermediate coolant can ruin all efforts. Therefore, when laying out a circuit of any variation, it is necessary to use the labor of exclusively qualified specialists and during the operation of the system, eliminate the risk of its depressurization.

DIY heat pump. Assembly and installation

Of course, the initial investment in organizing home heating using this technology is very high. Therefore, many ordinary people who are interested in this ultra-economical system have a desire to save at least a little by building it themselves.

To do this you need:

Buy a compressor. Any functional unit from a household split air conditioning system will do.
Build a capacitor. In the simplest case, it can be the usual stainless steel tank with a volume of 100 liters. It is cut in half, and a coil of small diameter copper pipe is mounted inside it. The thickness of the coil wall must be at least one millimeter. After unfastening the coil, it is necessary to weld the tank back into a complete structure, observing the tightness conditions.
Assemble the evaporator. This could be a plastic 60-80 liter container with a ¾ inch pipe built into it.
To organize an external contour located in the ground, it is better to use modern– they are much more durable than classic metal ones and their installation is much more reliable and faster.

All that remains is to invite a refrigeration equipment technician, so that, using specialized equipment, he will qualitatively seal all the joints of the system and fill it with freon.

Watch a video about installing a Daikin Altherma heat pump:

This completes the installation of the heat generating unit. You can take advantage of all its advantages, the main one of which is low energy consumption - electricity with significant heat generation capacity.

A heating system is designed to maintain optimal indoor air temperature, regardless of the ambient temperature. This is a complex of elements that receive, transport and transmit a certain amount of heat to all rooms. Coolants are distinguished:

primary – transfers heat from the energy production system to the thermal carrier;
secondary - transfers heat to the room through heating devices.

The home heating system is one of the important and necessary conditions for the construction of buildings. Includes 3 elements:

source of thermal energy;
communications (heat pipelines);
heating devices (radiators).

Pump equipment

Household pumps and their types

For more than two thousand years, humanity has been using pumping equipment. During this time, it was constantly improved and acquired many modifications, of which we can highlight two main groups:

submersible;
superficial.

Pumps pump out water from wells, the bowels of the earth, wells, cesspools, and increase water pressure in hydraulic systems. Household pumps can be electrically powered, internal combustion engine-powered or manual.

Pumps in heating systems

The most important achievement in the use of pumping equipment is the ability to completely eliminate the need to use solid fuel, gas and other purchased heat sources. In Europe, home owners strive to install a heating system that works due to natural energy through heat pumps. For the domestic market, the installation of such systems is new. Heat pumps can be part of integrated systems that heat and cool spaces. HP (heat pumps) are modified depending on the energy source (water, earth, air).

Heat pump device

A heat pump is a refrigerator that transfers heat from inside to outside.

Such a system includes:

Heat pump;
intake equipment (geothermal probes, collectors);
heat distribution system (radiators, heated floors, walls).

The heat pump consists of:

evaporator;
capacitor;
expansion valve (expansion valve that reduces pressure by diluting the gas);
compressor (which liquefies the gas and increases the pressure).

Operating principle

The general model shows the operating principle of the system. To make it easier to understand the whole process, we will proceed from simple to complex. First, let's imagine a closed loop with gas driven by a compressor. By adding an expansion valve, two areas will be formed in the system: with high and low pressure. Being compressed gas heats up, and when the pressure decreases, it cools. Moreover, the highest gas temperature is observed immediately at the exit from the compressor, and the lowest gas temperature in the system is at the point of exit from the expansion valve.

By adding two heat exchangers to the system, on the one hand, the heated gas will transfer part of the heat to the consumer through the condenser heat exchanger, on the other hand, the already cooled gas through the evaporator heat exchanger will absorb heat from an external source. This model has heat pump functions.

Full view of TN represents after connection to a source of low-temperature heat (geothermal probes) and a heating system (radiators, heated floors and walls).

Coolant (refrigerant) circulates in the intermediate circuit, the boiling point of which is slightly above -5 ° C. In one part of the cycle it is a liquid, and in the other it is a gas.

Freon is usually used. Initially it is in a liquid state. As it heats up, its temperature rises. When heated, freon turns into a gas with a temperature of about five degrees.

Further along the chain, the gas enters the compressor, which compresses it. As a result, the maximum amount of heat possible for the installation is released at the output (from +35 to +60-65 ° C). After hot gas enters the condenser, where heat is transferred from the coolant to the circuits of the room heating system.

Having given up most of the thermal energy, gaseous freon enters the expansion valve. Passing through this valve, the pressure and temperature drop sharply, the values of which at the point of exit from the valve are the lowest in the cycle.

The movement then repeats the circle.

Alternative fuel for heat pumps

An engineering solution such as a heat pump provides an amazing opportunity to obtain heat from inexhaustible basic natural sources and be independent of purchased energy resources. The sun heats the air, water, and earth. At any time of the year, almost everywhere, these sources have low-grade heat. So heat pumps come in the following categories:

ground (ground-water);
aquatic (water-water);
air (air-water).

Soil pumps

It is known that below the freezing point, the soil has a consistently positive temperature (+4-6 ° C). Here two principles have been developed for obtaining heat for heating through:

horizontal contour;
vertical collector.

Horizontal geothermal circuit

Required depending on the type of soil:

area from 200 m2 or more;
pit with a depth of 1.2 to 2 m.

Too deep the ground does not accumulate heat, and there is no need to dig deeper trenches. Depending on the area, polyethylene pipes are laid in a horizontal snake (loop, snail) in trenches, filled with antifreeze (antifreeze liquid), pressed, and buried. The total length of the circuit is approximately calculated as 5 m.p. of pipe per 1 m2 of area of the heated house. It is possible to use spiral laying, which saves a little space. N disadvantages:

pros.

This method is considered the most effective. On average, output per 1 m2 varies from 30 to 65-75 W in any environmental conditions. If it is not possible to occupy a fairly large area for laying pipes, it is worth considering the option of using vertical contours.

Vertical probes

This method involves drilling several wells with a depth of 20 meters. At this distance from the surface, the earth begins to heat up and has a temperature of 8-10 ° C or more. The drilling depth depends on:

location of the building;
type of soil.

This option for installing a heat pump system for heating a building is characterized by:

significant preparatory and organizational and technical work;
the largest capital investments;
large occupied area (when drilling several wells, the minimum distance between them should not exceed 8 meters);
such a disadvantage as a gradual decrease in heat transfer over time at great depth of wells;
heat transfer per unit length 50-60 W.

Cluster drilling

There is a technology for drilling wells that does not require such large areas. This is cluster drilling. The difference here is that up to 4 m2 is allocated for the well; it can also be placed under the house. Geothermal heat pumps involve the use of pipes:

polymer;
corrosion-resistant metal.

The second option is more expensive, but here there are higher heat transfer rates per 1 m.p. for the same period of time, and it is also possible to reduce the depth of the wells. The service life of such heat pumps (heat pumps) is 50-70 years.

Water-to-water pumps

In the cold season, the water has a quite warm temperature of +5-7° C. The operation of such HPs is based on the use of open wells for the intake and discharge of groundwater. In practice, two methods are used:

polymer pipes, weighted with a load, are laid on the bottom of the reservoir. Productivity is approximately 30 W per 1 lm. This method is relatively easier to implement, but requires a large length of the circuit;
the use of a well-well, from which energy enters the heating system, and a well to drain cooled water.

Air source heat pumps

Air heat pump systems are much cheaper and simpler, but less efficient. There are two options for such pumps:

Split

Presented with external and internal boxes:

the first includes a fan and evaporator;
the second is a capacitor and an automatic control system. The compressor can be located in any of the boxes.

Mono

The components are placed in one block. The system can be installed both indoors and outdoors. The durability of airborne HP is about 20 years.

Benefits of choosing a heat pump heating system

The installation of such home heating systems is different:

Choosing to install a heat pump when there is no gas pipeline nearby is the most optimal solution. And competent preliminary calculations for designing a house, including the installation of heated floors and walls, the use of thermal insulation materials in the construction of enclosing structures, and the choice of the type of heat pump in the complex will give the maximum effect from the operation of the house.

A heat pump is a universal device that functionally combines the characteristics of an air conditioner, water heater and heating boiler. This device does not use conventional fuel; its operation requires renewable sources from the environment - energy from air, soil, water.

Therefore, a heat pump today is the most cost-effective unit, since its operation does not depend on the cost of fuel, and is also environmentally friendly, since the source of heat is not electricity or combustion products, but natural heat sources.

To better understand how a heat pump works for heating a home, it is worth remembering the principle of operation of a refrigerator. Here the working substance evaporates, releasing cold. In the pump, on the contrary, it condenses and produces heat.

Working principle of a heat pump

The entire process of the system is presented in the form of a Carnot cycle - named after the inventor. It can be described as follows. The coolant passes through the working circuit - air, earth, water, and their combinations , from where it is sent to the 1st heat exchanger - the evaporation chamber. Here it transfers the accumulated heat to the refrigerant circulating in the internal circuit of the pump.

Operating principle of a home heating heat pump

The liquid refrigerant enters the evaporation chamber, where low pressure and temperature (5 0 C) transform it into a gaseous state. The next stage is the transfer of gas to the compressor and its compression. As a result, the temperature of the gas increases sharply, the gas passes into the condenser, here it exchanges heat with the heating system. The cooled gas turns into liquid and the cycle repeats.

Advantages and disadvantages of heat pumps

The operation of heat pumps for heating a home can be controlled using specially installed thermostats. The pump automatically turns on when the medium temperature drops below a set value and turns off if the temperature exceeds a set point. Thus, the device maintains a constant temperature in the room - this is one of the advantages of the devices.

The advantages of the device are its efficiency - the pump consumes a small amount of electricity and environmental friendliness, or absolute safety for the environment. Main advantages of the device:

Reliability. The service life exceeds 15 years, all parts of the system have a high working life, energy fluctuations do not harm the system.
Safety. There is no soot, exhaust, open flame, gas leakage is excluded.
Comfort. The operation of the pump is silent, climate control and an automatic system, the operation of which depends on weather conditions, help create coziness and comfort in the house.
Flexibility. The device has a modern, stylish design and can be combined with any home heating system.
Versatility. Used in private and civil construction. Because it has a wide power range. Due to this, it can provide heat to rooms of any size - from a small house to a cottage.

The complex structure of the pump determines its main disadvantage - the high cost of equipment and its installation. To install the device, it is necessary to carry out excavation work in large volumes.

Heat pumps - classification

The operation of a heat pump for heating a house is possible in a wide temperature range - from -30 to +35 degrees Celsius. The most common devices are absorption (transfer heat through its source) and compression (circulation of the working fluid occurs due to electricity). Absorption devices are the most economical, but they are more expensive and have a complex design.

Classification of pumps by type of heat source:

Geothermal. They take away the heat of water or earth.
Airborne. They take away heat from the atmospheric air.
Secondary heat. They take away the so-called industrial heat - generated during production, heating, and other industrial processes.

The coolant can be:

Water from an artificial or natural reservoir, groundwater.
Priming.
Air masses.
Combinations of the above media.

Geothermal pump - principles of design and operation

A geothermal pump for heating a house uses the heat of the ground, which it selects with vertical probes or a horizontal collector. The probes are placed at a depth of up to 70 meters, the probe is located at a short distance from the surface. This type of device is the most effective because the heat source has a fairly high, constant temperature throughout the year. Therefore, it is necessary to spend less energy to transport heat.

Such equipment requires high installation costs. The cost of drilling wells is high. In addition, the area allocated for the collector must be several times larger than the area of the heated house or cottage. Important to remember: the land where the collector is located cannot be used for planting vegetables or fruit trees - the roots of the plants will be supercooled.

Using water as a heat source

A body of water is a source of large amounts of heat. For the pump, you can use non-freezing reservoirs from 3 meters deep or groundwater at a high level. The system can be implemented as follows: the heat exchanger pipe, weighed down with a load at the rate of 5 kg per 1 linear meter, is laid on the bottom of the reservoir. The length of the pipe depends on the footage of the house. For a room of 100 sq.m. The optimal pipe length is 300 meters.

In the case of using groundwater, it is necessary to drill two wells, located one after the other in the direction of the groundwater. A pump is placed in the first well, supplying water to the heat exchanger. Cooled water flows into the second well. This is the so-called open heat collection circuit. Its main disadvantage is that the groundwater level is unstable and can vary significantly.

Air is the most accessible source of heat

When using air as a heat source, the heat exchanger is a radiator, forcedly blown by a fan. If a heat pump is used to heat a house using an air-to-water system, the user receives the following benefits:

Possibility to heat the entire house. Water, acting as a coolant, is distributed through heating appliances.
With minimal energy costs, it is possible to provide residents with hot water supply. This is possible due to the presence of an additional heat-insulated heat exchanger with a storage tank.
Pumps of a similar type can be used to heat water in swimming pools.

If the pump operates on an air-to-air system, the coolant is not used to heat the room. Heating is carried out using the received thermal energy. An example of the implementation of such a scheme would be a conventional air conditioner set to heating mode. Today, all devices that use air as a heat source are inverter-based. In them, alternating current is converted into direct current, providing flexible control of the compressor and its operation without stopping. And this increases the resource of the device.

Heat pump - an alternative home heating system

Heat pumps are an alternative to modern heating systems. They are economical, environmentally friendly and safe to use. However, the high cost of installation work and equipment today does not allow the devices to be used everywhere. Now you know how a heat pump works for heating a house, and after calculating all the pros and cons, you can decide whether to install it.