How an air pump works. Heat pump for home heating: principle of operation, varieties and use

Among the main directions of development of engineering equipment for private households, one can single out an increase in productivity with ergonomics and an increase in functionality. At the same time, developers are increasingly paying attention to the energy efficiency of the technical equipment of communication systems. The heating infrastructure is considered to be the most costly, so companies are showing particular interest in the means of providing it. Among the most tangible results of work in this direction is the air heat pump, which replaces traditional heating equipment, increasing

Features of air heat pumps

The main difference lies in the way heat is generated. Most involve the use of traditional energy carriers as a source. However, in the case of air pumps for both heating and hot water, most of the energy is consumed directly from natural resources. About 20% of the total potential is allocated for supply from the usual stations. Thus, air thermal houses consume energy more economically and cause less damage to the environment. It is noteworthy that the conceptual versions of the pumps were developed in order to provide office space and enterprises. But in the future, technologies also covered the segment of household equipment, allowing ordinary users to use profitable sources of thermal energy.

Principle of operation

The entire working process is based on the circulation of the refrigerant taken from the source. Heating occurs after the condensation of air flows, which are compressed in the compressor. Further, the refrigerant in a liquid state passes directly into the heating system. Now we can take a closer look at the principle of coolant circulation in the pump design. In the gaseous state, the refrigerant is sent to the heat exchanger enclosed in the indoor unit. There it gives off heat to the room and turns into a liquid. At this stage, the receiver comes into play, which is also supplied to the air source heat pump. The principle of operation of the standard version of this device assumes that in this unit the liquid will exchange heat with a refrigerant that has a low pressure. As a result of this process, the temperature of the resulting mixture will decrease again, and the liquid will go to the outlet of the receiver. At the time of passage of the gaseous refrigerant through the pipe with reduced pressure in the receiver, its superheat increases, after which it fills the compressor.

Specifications

The main technical indicator is power, which in the case of home models varies from 2.5 to 6 kW. Semi-industrial ones can also be used in the communication support of private houses if a power potential of more than 10 kW is required. As for the dimensions of the pumps, they correspond to traditional air conditioners. Moreover, they can be confused in appearance with a split system. The standard block can have parameters of 90x50x35 cm. The weight also corresponds to typical climatic settings - an average of 40-60 kg. Of course, the main question concerns the range of temperatures covered. Since the air source heat pump is focused on the heating function, the upper limit is considered to be a target and reaches an average of 30-40 °C. True, versions with combined functions are also produced, which also produce room cooling.

Varieties of designs

There are several concepts for generating heat with an air pump. As a result, the design is sharpened specifically for the needs of a specific generation scheme. The most popular model involves the interaction in one system of air flows and a water carrier. The main classification divides structures according to the type of organization of functional blocks. So, there is a heat air pump in a monoblock housing, and there are also models that provide for the output of the system to the outside using an auxiliary segment. By and large, both models repeat the principle of operation of conventional air conditioners, only their functions and performance have been raised to a new level.

Application of modern technologies

Innovative developments largely led to the development of classical climate control systems. In particular, Mitsubishi uses a two-phase refrigerant injection scroll compressor in its models, which allows the equipment to perform its function regardless of temperature conditions. Even at -15 °C, a Japanese-designed heat air pump demonstrates a performance of up to 80%. In addition, the latest models are equipped with new control systems, which provide more convenient, safer and more efficient operation of installations. With all the manufacturability of the equipment, the possibility of its integration into traditional heating systems with boilers and boilers remains.

Making air pumps with your own hands

First of all, you need to purchase a compressor for future installation. It is fixed in the wall and performs the function of an outdoor unit of a conventional split system. Further, the complex is supplemented with a capacitor, which can be made independently. This operation will require a copper "coil" with a thickness of about 1 mm, which then must be placed in a plastic or metal case - for example, a tank or cistern. The prepared tube is wound around the core, which can be a cylinder with dimensions that allow it to be integrated into the tank. Using a perforated one, it is possible to form turns with the same intervals, which will make the air more efficient, many home craftsmen perform it with the subsequent injection of freon, which will act as a refrigerant. Further, the assembled structure is connected to the heating system of the house through an external circuit.

Do you want to equip your house with convector heating, where an air-to-air heat pump is used to heat the coolant, which provides significant savings in heating costs? Agree that getting full-fledged heating in a company with hot water is practically free of charge - a very tempting event.

But you do not know how to build such a system in order to heat rooms in an alternative way and get hot water for domestic needs?

We will help to deal with this issue - the article highlights the principle of operation and the design of the pump. The energy of such a system will have to be spent only on the operation of the compressor, and the main volume of heat will be taken simply from the outside from the atmosphere, for which we do not yet require money.

The advantages of its introduction into the system and significant disadvantages are also considered. Special attention is paid to the selection and calculation of the pump.

And for those who like to do everything with their own hands, we suggest building a similar pump on their own, using improvised materials. To help, we provide photographic materials and video recommendations on the design and operation of an air heat pump.

Any heat pump belongs to the equipment from the sphere. It takes the thermal energy of the air masses on the street, from the surrounding space in the room, in order to heat residential and non-residential objects with it.

It does not use any combustible fuels.

External heat pump ( TN) air-to-air is similar to an inverter air conditioner, from an outdoor and indoor unit.

And according to the principle of operation, it is more like a refrigerator, only it acts “vice versa”. But unlike both of them, this heat pump is capable of both cooling and heating the air masses in the house.

Principle of operation and internal structure

The operation of an air-to-air heat pump is based on a simple physical phenomenon of thermodynamics - during evaporation, the liquid cools the surface from which it dissipates. For example, steam over a mug of hot tea exhibits the same effect.

This is the same principle that a regular refrigerator works on. Inside it are pipes through which the refrigerant circulates under high pressure. It draws heat from the interior of the freezer, warming up slightly at the same time.

Then the collected heat is released into the air of the room through a heat exchanger (grille at the back of the refrigerator).

And in order for the refrigerant to cool down to operating temperatures, it is compressed in the compressor. Moreover, during the cycle of operation, freon inside the system constantly changes from a gaseous state to a liquid state and vice versa.

An air source heat pump functions in exactly the same way. Only he takes heat from the street, and not from a closed freezer. Even if it is cold outside, there is still a lot of thermal energy in the atmosphere.

The heat pump only needs the energy used to run the compressor to produce heat. The diagram shows the process of heat transfer in detail.

The air-to-air heat pump consists of the following elements:

• compressor;
• evaporator with forced air fan;
• expansion valve;
• copper tubes for pumping freon between the street and the house;
• condenser with a fan for supplying heated air to the room.

The first three elements make up the outdoor unit, while the last one refers to the inside of the heat pump. Thermally insulated copper tubes are designed for continuous movement of the coolant between these modules of the split system.

The operation algorithm of an air-to-air heat pump is as follows:

1. Outdoor air is drawn into the outdoor unit by the fan and forced through the fins of the outdoor evaporator. Freon circulating through the heat exchanger absorbs the thermal energy available in it, while passing into a gaseous state.
2. The gas then enters the condenser where it is compressed. And then it is pumped through copper pipes to the indoor unit.
3. In the condenser located in the house, the gas passes back into the liquid, transferring heat to the indoor air.
4. Then the excess pressure is released through the expansion valve, and the liquid freon is again sent to the primary evaporator.

The value of the temperature of the freon entering the outdoor unit is always lower than the ambient temperature. Therefore, it always takes heat from the atmosphere.

But the level of “cooling” of the coolant in the system is constant, and the outside temperature is constantly fluctuating. For this reason, in severe frosts, the HP loses its effectiveness.

Air-to-air heat pumps are highly efficient devices. They are easy to maintain, convenient to operate and economical.

There is a huge range of such systems on sale now, for any home you can choose a heating installation. It is only necessary to correctly calculate its power, then it will effectively serve for many years.

What do you think about the efficiency and feasibility of using air-to-air heat pumps? Share your opinion, leave feedback on the use of units and ask questions. The comment form is located below.

Combustion of classical fuels (gas, wood, peat) is one of the ancient methods of generating heat. However, the depletion of traditional energy sources prompted people to look for more complex, but no less effective alternatives. One of them was the invention of a heat pump, whose work is based on the school laws of physics.

Heat pump operation

The principle of operation of heat pumps, which is very complicated at first glance, is based on several simple laws of thermodynamics and the properties of liquids and gases:

1. When a gas becomes liquid (condensation), heat is released
2. When a liquid changes to a gas (evaporation), heat is absorbed

Most liquids can boil at fairly high temperatures, close to 100 degrees. But there are substances with fairly low boiling points. In freon, it is about 3-4 degrees. Turning into a gas, it is easily compressed and the temperature inside the container begins to rise.

Theoretically, freon can be compressed to obtain any desired temperature, but in practice it is limited to 80-90 degrees, which is necessary for the full operation of a classical heating system.

Everyone encounters a heat pump more than once a day when they pass by a refrigerator. However, in it it works in the opposite direction, taking the heat of the products and dissipating it into the atmosphere.

Video about work technology

Heat pump diagram

The efficiency of most heat pumps is based on the heat of the ground, in which the temperature practically does not fluctuate throughout the year (within 7-10 degrees). Heat moves between three circuits:

1. Heating circuit
2. Heat pump
3. Brine (aka earthen) contour

The classical principle of operation of heat pumps in a heating system consists of the following elements:

1. Heat exchanger that gives the internal circuit the heat taken from the ground
2. compressing device
3. The second heat exchange device that transfers the energy received in the internal circuit to the heating system
4. The mechanism that lowers the pressure in the system (throttle)
5. Brine circuit
6. earth probe
7. Heating circuit

The pipe, which acts as the primary circuit, is placed in a well or buried directly in the ground. A non-freezing liquid coolant moves along it, the temperature of which rises to a similar characteristic of the earth (about +8 degrees) and enters the second circuit.

The secondary circuit takes heat from the liquid. Freon circulating inside begins to boil and transform into gas, which is sent to the compressor. The piston compresses it to 24-28 atm, due to which the temperature rises to + 70-80 degrees.

At this working stage, energy is concentrated into one small clot. As a result, the temperature rises.

The heated gas enters the third circuit, which is represented by hot water supply systems or even home heating. When transferring heat, losses of up to 10-15 degrees are possible, but they are not significant.

When freon cools down, there is a decrease in pressure, and it again turns into a liquid state. At a temperature of 2-3 degrees, it returns to the second circuit. The cycle repeats over and over.

Main types

The principle of operation of heat pumps is arranged so that they can be easily operated without interruption in a wide temperature range - from -30 to +40 degrees. The most popular are the following two types of models:

• absorption type
• Compression type

Absorption type models have a rather complex structure. They transfer the received thermal energy directly with the help of a source. Their operation significantly reduces the material costs of consumed electricity and fuel. Compression type models for heat transfer consume energy (mechanical and electrical).

Depending on the heat source used, pumps are divided into the following types:

1. Processing secondary heat- the most expensive models that have gained popularity for heating objects in the industry, in which the secondary heat generated by other sources is spent nowhere
2. Air- taking heat from the surrounding air
3. Geothermal– choose heat from water or earth

By type of input / output, all models can be classified as follows - soil, water, air and their various combinations.

Geothermal heat pumps

Popular are geothermal models of pumps, which are divided into two types: closed or open type.

The simple arrangement of open systems makes it possible to heat the water passing inside, which subsequently enters the ground again. Ideally, it works in the presence of an unlimited volume of pure heat transfer fluid, which, after consumption, does not harm the environment.

Closed systems of geothermal heat pumps are divided into the following types:

• Aquatic - located in a reservoir at an unfrozen depth
• With vertical arrangement - the collector is placed in a well to a depth of 200 m and is applicable in areas with uneven terrain
• With a horizontal arrangement - the collector is placed in the ground to a depth of 0.5-1 m, it is very important to provide a large circuit in a limited area

Air-to-water pump

One of the most versatile options is the air-to-water model. During the warm periods of the year, it is very effective, but in winter, productivity can drop significantly.

The advantage of the system is simple installation. Suitable equipment can be mounted in any convenient place, for example, on the roof. The heat that is removed from the room in the form of gas or smoke can be reused.

Water-to-water type

The water-to-water heat pump is one of the most efficient. But its use may be limited by the presence of a reservoir nearby or insufficient depth at which there is no significant drop in temperature in winter.

Low potential energy can be selected from the following sources:

• ground water
• Open type reservoirs
• Waste industrial water

The simplest principle of operation of heat pumps is for models that take heat from a reservoir. If the decision is made to use groundwater, a well may need to be drilled.

Soil-water type

Heat from the ground can be obtained throughout the year, since at depths of 1 m or more, the temperature practically does not change. As a heat carrier, "brine" is used - a non-freezing liquid that circulates.

One of the disadvantages of the "soil-water" system is the need for a large area to achieve the desired efficiency. They try to level it by laying pipes with rings.

The collector can be placed in a vertical position, but a well up to 150 m deep is required. Umbrellas are mounted at the bottom, which take away the heat of the soil.

Pros and cons of heating systems with a heat pump

Heat pumps are widely used in heating systems for private residential areas or industrial areas. They are gradually replacing more classical energy sources due to their reliability and efficiency.

Some of the many benefits of using a heat pump include:

• Saving money on maintenance of systems and coolant
• Pumps operate completely autonomously
• No harmful combustion products and other toxic substances are released into the environment
• Fire safety of the mounted equipment
• The ability to easily reverse the operation of the system

Despite the many advantages, it is necessary to take into account the negative aspects of operating a heat pump:

• Large initial investment in the arrangement of the heating system - from 3 to 10 thousand dollars
• In cold periods, when the temperature drops below -15 degrees, it is necessary to think about alternative heating options.
• Heating based on the operation of a heat pump is most effective only in systems with a low-temperature heat carrier

Another schematic video:

Summing up

Having learned and mastered the principle of operation of a heat pump, you can think and decide on the appropriateness of its installation and use. The initial costs, which may seem very large, will soon pay off and begin to bring a kind of profit in the form of savings on classic fuel.

One type of heat pump with a simple design is the air-to-air heat pump. The principle of operation of the pump is similar to that of a geothermal heat pump. The difference lies in the fact that the heat is not taken from the ground or water, but from the outside air masses. Accordingly, the heating of the building occurs by heating the air in the premises.

We can say that an air-to-air heat pump is an air conditioner in reverse. This is the main advantage of an air-to-air heat pump - for its installation and operation, drilling of wells and laying an underground circuit is not required.

If, for a number of reasons, it is not possible to lay the contour of an underground heat exchanger for heat extraction (there is no financial opportunity, there is not enough space on the site for horizontal laying, there is no groundwater under the site or there is no lake next to it, the presence of a granite layer at shallow depths) - a heat pump air-to-air type will be the most acceptable solution for economical and environmentally friendly heating.

The device and principle of operation of the air-to-air heat pump

The air-to-air heat pump consists of outdoor and indoor units. The outer, also known as the evaporation unit, is located outside the building. It is with its help that heat is extracted from the outside air. This heat heats the refrigerant, which boils into a gaseous state. The compressor then compresses this gas, significantly raising its temperature. The heat of the compressed gas is transferred to the condenser (indoor unit), which is located indoors. The condenser gives off heat to the indoor air. This process takes place continuously and is controlled automatically until the desired room temperature is reached.

If there is a need to heat several rooms or one large one, then in this case various systems of distribution and supply of warm air are used.

Due to the fact that heat pumps of this type heat only the air in the premises (there is direct air heating), such heat pumps can only be used for heating. That is, for heating water in the bathroom or kitchen, it is necessary to provide other solutions.

Pros of using

The advantage of an air-to-air heat pump, compared to an air-to-water pump, is the low temperature of the air that passes through the condenser coil. Simply put, if air-to-water heat pumps for high-quality heating require heating of the heat carrier (water) to sufficiently high temperatures, then in the case of an air-to-air heat pump, the required air heating temperature is much lower. Moreover, the efficiency coefficient of a heat pump is the higher, the smaller the difference between the temperature of the heat source and the temperature in the heating system.

The main advantages of an air-to-air heat pump:

• simplicity of design, installation and operation - for the installation of such heat pumps there is no need for drilling, laying complex communications, allotment of special rooms, etc.;
• the possibility of installation in almost any climatic zone;
• Heat pumps of this type can be installed in an already built house with an existing conventional heating system, thereby achieving significant savings in heating costs. Installation will require minimal modification and intervention to the existing design;
• have the lowest cost and the shortest payback period, in comparison with other types of heat pumps;
• low power consumption;
• autonomy, compactness and noiselessness of work;
• in summer, air-to-air heat pumps can be switched to cooling mode, and the presence of high-efficiency air filters will help create the required microclimate in the premises.

Disadvantages of an air-to-air heat pump

Unfortunately, air-to-air heat pumps also have their disadvantages. One of them is the dependence of the performance value on fluctuations in the outside air temperature.

At an outside air temperature of 0°C, the energy efficiency coefficient of the heat pump drops to the level of 2-2.5, that is, 2-2.5 kW of heat will be produced per 1 kW of energy consumed.

In comparison, at higher temperatures, these heat pumps have an energy efficiency factor of 3-4. And when the temperature drops to -20 ° C, the energy efficiency coefficient drops to 1. That is, it becomes necessary to heat the room by other means. Although, at the moment there are manufacturers with world-famous names that offer air-to-air heat pumps that can operate efficiently at temperatures down to -25°C.