Let's try to explain in the language of the common man what " HEAT PUMP«:
Heat pump - This special device, which combines a boiler, a source of hot water and an air conditioner for cooling. The main difference heat pump from other heat sources is the possibility of using renewable low-potential energy taken from environment(land, water, air, Wastewater) to cover heat needs during heating season, heating water for hot water supply and cooling the house. The heat pump therefore provides a highly efficient energy supply without gas or other hydrocarbons.
Heat pump is a device that works on the principle of a reverse chiller, transferring heat from a low-temperature source to a higher-temperature environment, such as your home's heating system.
Each heat pump system has the following main components:
- primary circuit - closed circulation system, which serves to transfer heat from the ground, water or air to the heat pump.
- secondary circuit - closed system, which serves to transfer heat from the heat pump to the heating, hot water supply or ventilation system (supply heating) in the house.
Working principle of a heat pump similar to the operation of an ordinary refrigerator, only in reverse. The refrigerator takes heat from food products and transfers it outside (to the radiator placed on its back wall). A heat pump transfers heat accumulated in the soil, ground, reservoir, groundwater or air into your home. Like a refrigerator, this energy-efficient heat generator has the following main elements:
- a condenser (a heat exchanger in which heat is transferred from the refrigerant to the elements of the room heating system: low-temperature radiators, fan coil units, warm floor, radiant heating/cooling panels);
- throttle (a device that serves to reduce pressure, temperature and, as a result, close the heating cycle in the heat pump);
- evaporator (heat exchanger in which heat is taken from a low-temperature source to a heat pump);
- compressor (a device in which the pressure and temperature of the refrigerant vapor increases).
Heat pump arranged in such a way as to make the heat move in different directions. For example, during the heating of a house, heat is taken from some cold external source (land, river, lake, outdoor air) and transferred to the house. To cool (condition) a house, heat is taken from more warm air in the house and transferred outside (discarded). In this respect, a heat pump is similar to a conventional one hydraulic pump, which pumps liquid from the lower level to the upper level, while in ordinary conditions fluid always moves from top to bottom.
Today, the most common are vapor compression heat pumps. The principle of their action is based on two phenomena: firstly, the absorption and release of heat by the liquid when the state of aggregation changes - evaporation and condensation, respectively; secondly, the change in the temperature of evaporation (and condensation) with a change in pressure.
In the evaporator of a heat pump, there is a working fluid - a refrigerant that does not contain chlorine - it is under low pressure and boils at a low temperature, absorbing heat from a low-grade source (for example, soil). Then the working fluid is compressed in the compressor, which is driven by an electric or other motor, and enters the condenser, where high pressure condenses at more high temperature, giving off the heat of condensation to a heat receiver (for example, the heat carrier of the heating system). From the condenser, the working fluid through the throttle again enters the evaporator, where its pressure decreases, and the refrigerant boiling process begins anew.
Heat pump is able to take heat from various sources, for example, air, water, soil. Also, it can release heat into air, water or ground. A warmer environment that receives heat is called a heat sink.
Heat pump X/Y uses medium X as heat source and Y heat carrier. A distinction is made between pumps "air-to-water", "soil-to-water", "water-to-water", "air-to-air", "soil-to-air", "water-to-air".
Heat pump "ground-water":
Air-to-water heat pump:
Regulation of the operation of a heating system using heat pumps in most cases is carried out by turning it on and off according to a signal from a temperature sensor, which is installed in the receiver (when heating) or the source (when cooling) of heat. Setting up a heat pump is usually done by changing the cross-section of the throttle (thermostatic valve).
Like a refrigeration machine, a heat pump uses mechanical (electrical or other) energy to drive a thermodynamic cycle. This energy is used to drive the compressor (modern heat pumps with a power of up to 100 kW are equipped with highly efficient scroll compressors).
(transformation or efficiency coefficient) of a heat pump is the ratio of the amount of thermal energy that the heat pump produces to the amount electrical energy that it consumes.
COP conversion factor depends on the temperature level in the evaporator and condenser of the heat pump. This value varies for various heat pump systems in the range from 2.5 to 7, that is, for 1 kW of electrical energy expended, the heat pump produces from 2.5 to 7 kW of thermal energy, which is beyond the power of either a condensing gas boiler or any other generator. heat.
Therefore it can be argued that heat pumps produce heat using minimal amount expensive electrical energy.
Energy saving and efficiency of use of a heat pump primarily depends on where you decide to draw low-temperature heat from, secondly - from the method of heating your home (water or air) .
The fact is that the heat pump works as a “transfer base” between two thermal circuits: one heating at the inlet (on the evaporator side) and the second, heating at the outlet (condenser).
All types of heat pumps have a number of features that you need to remember when choosing a model:
Firstly, a heat pump only pays off in a well-insulated house. The more warm house, the greater the benefit when using this device. As you understand, heating the street using a heat pump, collecting crumbs of heat from it, is not entirely reasonable.
Second, than more difference coolant temperatures in the input and output circuits, the lower the heat conversion coefficient (COR), that is, the lower the savings in electrical energy. That is why more profitable connection of a heat pump to low-temperature heating systems. First of all, we are talking about heating with water heated floors or infrared water ceiling or wall panels. But the more hot water The heat pump prepares for the output circuit (radiators or shower), the less power it develops and the more electricity it consumes.
Thirdly, to achieve greater benefits, it is practiced to operate a heat pump with an additional heat generator (in such cases they talk about using bivalent heating circuit ).
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Heat pumps for home heating: pros and cons
1. Features of heat pumps
2. Types of heat pumps
3. Geothermal heat pumps
4. Advantages and disadvantages of heat pumps
One of the highly efficient methods of heating a country house is the use of heat pumps.
The operating principle of heat pumps is based on the extraction of thermal energy from the soil, reservoirs, groundwater, and air. Heat pumps for heating your home do not have a harmful impact on the environment. You can see what such heating systems look like in the photo.
Such organization of home heating and hot water supply has been possible for many years, but it began to become widespread only recently.
Features of heat pumps
The operating principle of such devices is similar to refrigeration equipment.
Heat pumps take heat, accumulate it and enrich it, and then transfer it to the coolant. A condenser is used as a heat-generating device, and an evaporator is used to recover low-potential heat.
The constant increase in the cost of electricity and the imposition of strict environmental protection requirements is causing the search for alternative methods of generating heat for heating houses and heating water.
One of them is the use of heat pumps, since the amount of thermal energy received is several times greater than the electricity consumed (more details: “Economical heating with electricity: pros and cons”).
If we compare heating with gas, solid or liquid fuel, with heat pumps, the latter will be more economical. However, the installation of a heating system with such units is much more expensive.
Heat pumps consume the electricity needed to run the compressor. Therefore, this type of heating of buildings is not suitable if there are frequent problems with power supply in the area.
Heating a private house with a heat pump can have different efficiency; its main indicator is heat conversion - the difference between the electricity consumed and the heat received.
There is always a difference between the evaporator and condenser temperatures.
The higher it is, the lower the efficiency of the device. For this reason, when using a heat pump, you need to have a considerable source of low potential heat. Based on this, it follows that the larger the size of the heat exchanger, the lower the energy consumption. But at the same time, devices with large dimensions have a much higher cost.
Heating using a heat pump is found in many developed countries.
Moreover, they are also used for heating apartments and public buildings - this is much more economical than the heating system familiar in our country.
Types of heat pumps
These devices can be used over a wide temperature range. Usually they work normally at temperatures from – 30 to + 35 degrees.
The most popular are absorption and compression heat pumps.
The latter of them use mechanical and electrical energy to transfer heat. Absorption pumps are more complex, but they are able to transfer heat using the source itself, thereby significantly reducing energy costs.
As for heat sources, these units are divided into the following types:
- air;
- geothermal;
- secondary heat.
Air heat pumps for heating take heat from the surrounding air.
Geothermal uses the thermal energy of the earth, underground and surface waters (for more details: “Geothermal heating: principles of operation with examples”). Recycled heat pumps take energy from sewage and central heating - these devices are mainly used to heat industrial buildings.
This is especially beneficial if there are sources of heat that must be recycled (read also: “We use the heat of the earth to heat the house”).
Heat pumps are also classified by type of coolant; they can be air, soil, water, or combinations thereof.
Geothermal heat pumps
Heating systems that use heat pumps are divided into two types - open and closed. Open structures are designed to heat the water passing through the heat pump. After the coolant passes through the system, it is discharged back into the ground.
Such a system works ideally only if there is a significant volume of clean water, taking into account the fact that its consumption will not harm the environment and will not conflict with current legislation. Therefore, before using a heating system that receives energy from groundwater, you should consult with the relevant organizations.
Closed systems are divided into several types:
- Geothermal with a horizontal arrangement involves laying the collector in a trench below the freezing depth of the soil.
This is approximately 1.5 meters. The collector is laid in rings in order to reduce the excavation area to a minimum and provide a sufficient circuit in a small area (read: “Geothermal heat pumps for heating: the principle of the system”).
This method is only suitable if there is sufficient free area available.
- Geothermal structures with a vertical arrangement involve placing the collector in a well up to 200 meters deep. This method is used when it is not possible to place the heat exchanger over a large area, which is necessary for a horizontal well.
Also, geothermal systems with vertical wells are made in case of uneven terrain of the site.
- Geothermal water means placing the collector in a reservoir at a depth below the freezing level. Laying is done in rings. Such systems cannot be used if the reservoir is small or insufficiently deep.
It must be taken into account that if the reservoir freezes at the level where the collector is located, the pump will not be able to work.
Heat pump air water - features, details on video:
Advantages and disadvantages of heat pumps
Heating a country house with a heat pump has both positive and negative sides. One of the main advantages of heating systems is environmental friendliness.
Heat pumps are also economical, unlike other heaters that consume electricity. Thus, the amount of generated thermal energy is several times greater than the consumed electricity.
Heat pumps are characterized by increased fire safety; they can be used without additional ventilation.
Since the system has a closed loop, financial expenses during operation are minimized - you only have to pay for the electricity consumed.
The use of heat pumps also allows you to cool the room in the summer - this is possible by connecting fan coils and a “cold ceiling” system to the collector.
These devices are reliable, and the control of work processes is fully automatic. Therefore, the operation of heat pumps does not require special skills.
The compact dimensions of the devices are also important.
The main disadvantage of heat pumps:
- high cost and significant installation costs. It is unlikely that you will be able to construct heating with a heat pump yourself without special knowledge. It will take more than one year for the investment to pay off;
- The service life of the devices is approximately 20 years, after which there is a high probability that major repairs will be required.
This, too, will cost dearly;
- the price of heat pumps is several times higher than the cost of boilers running on gas, solid or liquid fuel. A lot of money will have to be paid for drilling wells.
But on the other hand, heat pumps do not require regular maintenance, as is the case with many other heating devices.
Despite all the advantages of heat pumps, they are still not widely used. This is due, first of all, to the high cost of the equipment itself and its installation. It will be possible to save only if you create a system with a horizontal heat exchanger, if you dig trenches yourself, but this will take more than one day. As for the operation, the equipment is very profitable.
Heat pumps are an economical way to heat buildings that are environmentally friendly.
They may not be widely used due to their high cost, but the situation may change in the future. In developed countries, many owners of private houses use heat pumps - there the government encourages concern for the environment, and the cost of this type of heating is low.
Thermal ground or geothermal pump is one of the most energy efficient alternative energy systems. Its operation does not depend on the season and ambient temperature, as for an air-to-air pump, and is not limited by the presence of a reservoir or well with groundwater near the house, like a water-to-water system.
A ground-to-water heat pump, which uses heat taken from the soil to heat the coolant in the heating system, has the highest and most constant efficiency, as well as an energy conversion coefficient (ECR).
Its value is 1:3.5-5, that is, every kilowatt of electricity spent on pump operation is returned in 3.5-5 kilowatts of thermal energy. Thus, the heating power of the soil pump makes it possible to use it as the only source of heat even in a house with a large area, of course, when installing a unit of appropriate power.
A submersible soil pump requires equipment of a soil circuit with a circulating coolant to extract heat from the earth.
There are two possible options for its placement: a horizontal soil collector (a pipe system at a shallow depth, but a relatively large area) and a vertical probe placed in a well from 50 to 200 m deep.
The efficiency of heat exchange with soil significantly depends on the type of soil - moisture-filled soil gives off much more heat than, for example, sandy soil.
The most common are pumps operating on the ground-water principle, in which the coolant stores the energy of the soil and, as a result of passing through a compressor and heat exchanger, transfers it to water as a coolant in the heating system. The prices for this type of soil pumps correspond to their high efficiency and productivity.
Submersible Soil Pump
Any complex high-tech units, such as GRAT ground pumps, as well as soil heat pumps, require the attention of professionals.
Heat pump
We offer a full range of services for the sale, installation and maintenance of heating and hot water supply systems based on heat pumps.
Today, among the countries producing such units on the market, European countries and China are especially popular.
The most famous heat pump models: Nibe, Stiebel Eltron, Mitsubishi Zubadan, Waterkotte. The domestic ground source heat pump is also in no less demand.
Our company prefers to work only with equipment from reliable European manufacturers: Viessmann and Nibe.
The heat pump extracts accumulated energy from various sources - groundwater, artesian and thermal waters - waters of rivers, lakes, seas; treated industrial and domestic wastewater; ventilation emissions and flue gases; soil and the bowels of the earth - transfers and converts higher temperatures into energy.
Heat pump – highly economical, environmentally friendly heating and comfort technology
Thermal energy exists around us, the problem is how to extract it without spending significant energy resources.
Heat pumps extract accumulated energy from various sources - ground, artesian and thermal waters - waters of rivers, lakes, seas; purified industrial and domestic wastewater; ventilation emissions and flue gases; soil and the bowels of the earth - transfers and converts higher temperatures into energy.
The choice of the optimal heat source depends on many factors: the size of the energy needs of your home, the installed heating system, and the natural conditions of the region where you live.
The device and principle of operation of the heat pump
The heat pump functions like a refrigerator - just the other way around.
The refrigerator transfers heat from the inside to the outside.
A heat pump transfers heat accumulated in the air, soil, subsoil or water into your home.
The heat pump consists of 4 main units:
Evaporator,
Capacitor,
Expansion valve (discharge valve-
throttle, lowers pressure),
Compressor (increases pressure).
These units are connected by a closed pipeline.
The piping system circulates refrigerant, which is a liquid in one part of the cycle and a gas in the other.
Earth's interior as a deep heat source
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The earth's interior is a free heat source that maintains the same temperature all year round. Using the heat of the earth's interior is an environmentally friendly, reliable and safe technology for providing heat and hot water supply to all types of buildings, large and small, public and private. The level of investment is quite high, but in return you will receive an alternative heating system that is safe to operate, with minimal maintenance requirements and has the longest service life. Heat conversion coefficient (see. page 6) high, reaches 3. The installation does not require much space and can be installed on a small plot of land. The amount of restoration work after drilling is insignificant, the impact of the drilled well on the environment is minimal. There is no impact on groundwater levels since groundwater is not consumed. Thermal energy is transferred to the convection water heating system and used for hot water supply. |
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Ground heat - nearby energy
Heat accumulates in the surface layer of the earth during the summer.
Using this energy for heating is advisable for buildings with high energy consumption. The greatest amount of energy is extracted from soil with the highest moisture content.
Ground heat pump
Water heat sources
The sun heats the water in seas, lakes and other water sources.
Solar energy accumulates in water and bottom layers. Rarely does the temperature drop below +4 °C. The closer to the surface, the more the temperature varies throughout the year, but in depth it is relatively stable.
Heat pump with water heat source
The heat transfer hose is laid at the bottom or in the bottom soil, where the temperature is still slightly higher,
than water temperature.
It is important that the hose be weighted to prevent
the hose floats to the surface. The lower it lies, the lower the risk of damage.
A water source as a heat source is very effective for buildings with relatively high heat energy needs.
Groundwater heat
Even groundwater can be used to heat buildings.
This requires a drilled well, from where water is pumped into the heat pump.
When using groundwater, high demands are placed on its quality.
Heat pump with ground water as heat source
After passing through the heat pump, the water can be transported to a drainage channel or well. Such a solution may lead to an undesirable decrease in groundwater levels, as well as reduce the operational reliability of the installation and have a negative impact on nearby wells.
Nowadays this method is used less and less.
Groundwater can also be returned to the ground through partial or complete infiltration.
Such a good heat pump
Heat conversion coefficientThe higher the efficiency of the heat pump, the more profitable it is. Efficiency is determined by the so-called heat conversion coefficient or temperature transformation coefficient, which is the ratio of the amount of energy generated by the heat pump to the amount of energy expended in the heat transfer process. For example: The temperature transformation coefficient is 3. This means that the heat pump supplies 3 times more energy than it consumes. In other words, 2/3 was received “for free” from the heat source. How to make a heat pump for heating a house with your own hands: operating principle and diagramsThe higher the energy needs of your home, the more money you save. Note The value of the temperature transformation coefficient is affected by the presence/ignoring of parameters of additional equipment (circulation pumps) in the calculations, as well as various temperature conditions. The lower the temperature distribution, the higher the temperature transformation coefficient becomes; heat pumps are most effective in heating systems with low temperature characteristics. |
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When selecting a heat pump for your heating system, it is not profitable to orient Experience shows that the heat pump should generate about 50-70% of this maximum, the heat pump should cover 70-90% (depending on the heat source) of the total annual energy demand for heating and hot water supply. At low external temperatures, the heat pump is used with existing boiler equipment or a peak closer, which is equipped with the heat pump. |
Comparison of costs for installing a heating system for an individual house based on a heat pump and an oil boiler.
For analysis, let’s take a house with an area of 150-200 sq.m.
The most common version of a modern country house for permanent use today.
The use of modern building materials and technologies ensures the building’s heat loss at the level of 55 W/sq.m of floor.
To cover the total needs for thermal energy spent on heating and hot water supply of such a house, it is necessary to install a heat pump or boiler with a thermal capacity of approximately 12 kW/h.
The cost of the heat pump or diesel boiler itself is only a fraction of the costs that must be incurred to commission the heating system as a whole.
Below is a far from complete list of the main associated costs for installing a turnkey heating system based on a liquid fuel boiler, which are absent when using a heat pump:
air vent filter, fix package, safety group, burner, boiler piping system, control panel with weather-dependent automatics, emergency electric boiler, fuel tank, chimney, boiler.
All this adds up to at least 8000-9000 euros. Taking into account the need to install the boiler room itself, the cost of which, taking into account all the requirements of the supervisory authorities, is several thousand euros, we come to a conclusion that is paradoxical at first glance, namely, the practical comparability of the initial capital costs when installing a turnkey heating system based on a heat pump and a liquid fuel boiler.
In both cases, the cost is close to 15 thousand euros.
Considering the following undeniable advantages of a heat pump, such as:
Economical. At the cost of 1 kW of electricity is 1 ruble 40 kopecks, 1 kW of thermal power will cost us no more than 30-45 kopecks, while 1 kW of thermal energy from the boiler will already cost 1 ruble 70 kopecks (at a price of diesel fuel of 17 rubles/l);
Ecology. An environmentally friendly heating method for both the environment and the people in the room;
Safety. There is no open flame, no exhaust, no soot, no diesel smell, no gas leakage, no fuel oil spill.
There are no fire hazardous storage facilities for coal, firewood, fuel oil or diesel fuel;
Reliability. A minimum of moving parts with a high service life. Independence from the supply of fuel material and its quality. Virtually no maintenance required. The service life of the heat pump is 15 – 25 years;
Comfort. The heat pump operates silently (no louder than a refrigerator);
Flexibility. The heat pump is compatible with any circulation heating system, and its modern design allows it to be installed in any room;
An increasing number of individual home owners are choosing a heat pump for heating, both in new construction and when upgrading an existing heating system.
Heat pump device
The near-surface technology of using low-grade thermal energy using a heat pump can be considered as some kind of technical and economic phenomenon or a real revolution in the heat supply system.
Heat pump device. The main elements of a heat pump are an evaporator, a compressor, a condenser and a flow regulator connected by a pipeline - a throttle, expander or vortex tube (Fig. 16).
Schematically, a heat pump can be represented as a system of three closed circuits: in the first, external, a heat sink (a coolant that collects heat from the environment) circulates, in the second - a refrigerant (a substance that evaporates, taking away the heat of the heat sink, and condenses, giving up heat to the heat sink) , in the third - a heat receiver (water in the heating and hot water supply systems of the building).
16. Heat pump device
The external circuit (collector) is a pipeline laid in the ground or in water in which a non-freezing liquid - antifreeze - circulates. It should be noted that the source of low-potential energy can be either heat of natural origin (outside air; heat of ground, artesian and thermal waters; water of rivers, lakes, seas and other non-freezing natural bodies of water) and man-made origin (industrial discharges, wastewater treatment plants, heat from power transformers and any other waste heat).
The temperature required for pump operation is usually 5-15 °C.
The second circuit, where the refrigerant circulates, has built-in heat exchangers - an evaporator and a condenser, as well as devices that change the pressure of the refrigerant - a choke (a narrow calibrated hole) that sprays it in the liquid phase and a compressor that compresses it in the gaseous state.
Duty cycle. The liquid refrigerant is forced through the throttle, its pressure drops, and it enters the evaporator, where it boils, taking away the heat supplied by the collector from the environment.
Next, the gas into which the refrigerant has turned is sucked into the compressor, compressed and, heated, pushed into the condenser. The condenser is the heat-releasing unit of the heat pump: here the heat is received by the water in the heating circuit system. In this case, the gas cools and condenses in order to be discharged again in the expansion valve and return to the evaporator. After this, the working cycle is repeated.
In order for the compressor to work (maintain high pressure and circulation), it must be connected to electricity.
But for every kilowatt-hour of electricity expended, the heat pump produces 2.5-5 kilowatt-hours of thermal energy.
Heat pump for heating: principle of operation and advantages of use
This ratio is called the transformation ratio (or heat conversion ratio) and serves as an indicator of the efficiency of the heat pump.
The value of this value depends on the difference in temperature levels in the evaporator and condenser: the greater the difference, the smaller it is. For this reason, the heat pump should use as much of the low-grade heat source as possible, without trying to cool it too much.
Types of heat pumps.
Heat pumps come in two main types – closed loop and open loop.
Open circuit pumps They use water from underground sources as a heat source - it is pumped through a drilled well into a heat pump, where heat exchange occurs, and the cooled water is discharged back into the underwater horizon through another well.
This type of pump is advantageous because the underground water maintains a stable and fairly high temperature all year round.
Closed cycle pumps There are several types: vertical and g horizontal(Fig. 17).
Pumps with a horizontal heat exchanger have a closed external circuit, the main part of which is dug horizontally into the ground, or laid along the bottom of a nearby lake or pond.
The depth of underground pipes in such installations is up to a meter. This method of obtaining geothermal energy is the cheapest, but its use requires a number of technical conditions that are not always available in the area being developed.
The main thing is that the pipes should be laid in such a way as not to interfere with the growth of trees or agricultural work, so that there is a low probability of damage to underwater pipes during agricultural or other activities.
Rice. 17. Near-surface geothermal system with heat exchange
Pumps with vertical heat exchanger include an external contour dug deep into the ground - 50-200 m.
This is the most efficient type of pump and produces the cheapest heat, but is much more expensive to install than previous types. The benefit in this case is due to the fact that at a depth of more than 20 meters, the temperature of the earth is stable all year round and amounts to 15-20 degrees, and only increases with increasing depth.
Air conditioning using heat pumps. One of the important qualities of heat pumps is the ability to switch from heating mode in winter to air conditioning mode in summer: only fan coils are used instead of radiators.
A fan coil is an internal unit into which heat or coolant and air driven by a fan are supplied, which, depending on the temperature of the water, is either heated or cooled.
Includes: heat exchanger, fan, air filter and control panel.
Since fan coil units can operate for both heating and cooling, several piping options are possible:
- S2 - pipe - when the role of heat and coolant is played by water and their mixing is allowed (and, as an option, a device with an electric heater and a heat exchanger that works only for cooling);
- S4 - pipe - when the coolant (for example, ethylene glycol) cannot be mixed with the coolant (water).
The power of fan coil units for cold ranges from 0.5 to 8.5 kW, and for heat – from 1.0 to 20.5 kW.
They are equipped with low-noise (from 12 to 45 dB) fans with up to 7 rotation speeds.
Prospects. The widespread use of heat pumps is hampered by lack of public awareness. Potential buyers are frightened by the rather high initial costs: the cost of the pump and installation of the system is $300-1200 per 1 kW of required heating power. But a competent calculation convincingly proves the economic feasibility of using these installations: capital investments pay off, according to rough estimates, in 4-9 years, and heat pumps last 15-20 years before major repairs.
This autumn, there has been an aggravation in the network about heat pumps and their use for heating country houses and summer cottages. In a country house that I built with my own hands, such a heat pump has been installed since 2013. This is a semi-industrial air conditioner that can effectively work for heating at outdoor temperatures down to -25 degrees Celsius. It is the main and only heating device in a one-story country house with a total area of 72 square meters.
2. Let me briefly remind you of the background. Four years ago, I bought a 6-acre plot of land from a gardening partnership, on which I, with my own hands, without hiring hired labor, built a modern, energy-efficient country house. The purpose of the house is a second apartment located in nature. Year-round, but not constant operation. Maximum autonomy was required in conjunction with simple engineering. There is no main gas in the area where SNT is located and you should not count on it. Imported solid or liquid fuel remains, but all these systems require complex infrastructure, the cost of construction and maintenance of which is comparable to direct heating with electricity. Thus, the choice was already partially predetermined - electric heating. But here a second, no less important point arises: the limitation of electrical capacity in the gardening partnership, as well as fairly high electricity tariffs (at that time - not a “rural” tariff). In fact, 5 kW of electrical power has been allocated to the site. The only way out in this situation is to use a heat pump, which will save about 2.5-3 times on heating compared to direct conversion of electrical energy into heat.
So, let's move on to heat pumps. They differ in where they take heat from and where they release it. An important point, known from the laws of thermodynamics (8th grade of high school) - a heat pump does not produce heat, it transfers it. That is why its ECO (energy conversion coefficient) is always greater than 1 (that is, the heat pump always gives out more heat than it consumes from the network).
The classification of heat pumps is as follows: “water - water”, “water - air”, “air - air”, “air - water”. “Water” indicated in the formula on the left means the extraction of heat from a liquid circulating coolant passing through pipes located in the ground or reservoir. The effectiveness of such systems is practically independent of the time of year and ambient temperature, but they require expensive and labor-intensive excavation work, as well as the availability of sufficient free space for laying a ground heat exchanger (on which, subsequently, it will be difficult for anything to grow in the summer, due to freezing of the soil) . The “water” indicated in the formula on the right refers to the heating circuit located inside the building. This can be either a radiator system or liquid heated floors. Such a system will also require complex engineering work inside the building, but it also has its advantages - with the help of such a heat pump you can also get hot water in the house.
But the most interesting category is the air-to-air heat pump category. In fact, these are the most common air conditioners. While working for heating, they take heat from the street air and transfer it to an air heat exchanger located inside the house. Despite some disadvantages (production models cannot operate at ambient temperatures below -30 degrees Celsius), they have a huge advantage: such a heat pump is very easy to install and its cost is comparable to conventional electric heating using convectors or an electric boiler.
3. Based on these considerations, a Mitsubishi Heavy ducted semi-industrial air conditioner, model FDUM71VNX, was selected. As of autumn 2013, a set consisting of two blocks (external and internal) cost 120 thousand rubles.
4. The external unit is installed on the facade on the north side of the house, where there is the least wind (this is important).
5. The indoor unit is installed in the hall under the ceiling; from it, with the help of flexible, sound-insulated air ducts, hot air is supplied to all living spaces inside the house.
6. Because The air supply is located under the ceiling (it is absolutely impossible to organize a hot air supply near the floor in a stone house), then it is obvious that the air needs to be taken in on the floor. To do this, using a special duct, the air intake was lowered to the floor in the corridor (all interior doors also have flow grilles installed in the lower part). The operating mode is 900 cubic meters of air per hour, due to constant and stable circulation there is absolutely no difference in air temperature between the floor and ceiling in any part of the house. To be precise, the difference is 1 degree Celsius, which is even less than when using wall-mounted convectors under windows (with them the temperature difference between the floor and ceiling can reach 5 degrees).
7. In addition to the fact that the internal unit of the air conditioner, due to its powerful impeller, is capable of circulating large volumes of air throughout the house in recirculation mode, we must not forget that people need fresh air in the house. Therefore, the heating system also serves as a ventilation system. Through a separate air channel, fresh air is supplied to the house from the street, which, if necessary, is heated (in the cold season) using automation and a duct heating element.
8. Hot air is distributed through grilles like this, located in living rooms. It is also worth paying attention to the fact that there is not a single incandescent lamp in the house and only LEDs are used (remember this point, it is important).
9. Exhausted “dirty” air is removed from the house through an exhaust hood in the bathroom and kitchen. Hot water is prepared in a conventional storage water heater. In general, this is a fairly large expense item, because... Well water is very cold (from +4 to +10 degrees Celsius depending on the time of year) and someone may reasonably note that solar collectors can be used to heat water. Yes, you can, but the cost of investing in infrastructure is such that for this money you can heat water directly with electricity for 10 years.
10. And this is “TsUP”. Main and main control panel for air source heat pump. It has various timers and simple automation, but we use only two modes: ventilation (during the warm season) and heating (during the cold season). The built house turned out to be so energy efficient that the air conditioner in it was never used for its intended purpose - to cool the house in the heat. LED lighting played a big role in this (heat transfer from which tends to zero) and very high-quality insulation (it's no joke, after arranging the lawn on the roof, we even had to use a heat pump this summer to heat the house - on days when the average daily temperature dropped below + 17 degrees Celsius). The temperature in the house is maintained year-round at least +16 degrees Celsius, regardless of the presence of people in it (when there are people in the house, the temperature is set to +22 degrees Celsius) and the supply ventilation never turns off (because laziness).
11. A technical electricity meter was installed in the fall of 2013. That is exactly 3 years ago. It is easy to calculate that the average annual consumption of electrical energy is 7000 kWh (in fact, this figure is slightly lower now, because in the first year the consumption was high due to the use of dehumidifiers during finishing work).
12. In the factory configuration, the air conditioner is capable of heating at an ambient temperature of at least -20 degrees Celsius. To work at lower temperatures, refinement is required (in fact, it is relevant when operating even at a temperature of -10, if the humidity is high outside) - installing a heating cable in a drainage pan. This is necessary so that after the defrosting cycle of the outdoor unit, the liquid water has time to leave the drain pan. If she does not have time to do this, then ice will freeze in the pan, which will subsequently squeeze out the frame with the fan, which will probably lead to the breaking of the blades on it (you can see photos of the broken blades on the Internet, I almost encountered this myself because . did not put the heating cable in immediately).
13. As I mentioned above, exclusively LED lighting is used everywhere in the house. This is important when it comes to air conditioning a room. Let's take a standard room in which there are 2 lamps, 4 lamps in each. If these are 50-watt incandescent bulbs, then they will consume a total of 400 watts, while LED bulbs will consume less than 40 watts. And all energy, as we know from the physics course, ultimately turns into heat anyway. That is, incandescent lighting is such a good medium-power heater.
14. Now let's talk about how a heat pump works. All it does is transfer thermal energy from one place to another. This is exactly the same principle that refrigerators operate on. They transfer heat from the refrigerator compartment to the room.
There is such a good riddle: How will the temperature in the room change if you leave a refrigerator plugged in with the door open? The correct answer is that the temperature in the room will rise. To make it easier to understand, this can be explained this way: the room is a closed circuit, electricity flows into it through wires. As we know, energy ultimately turns into heat. That is why the temperature in the room will rise, because electricity enters the closed circuit from the outside and remains in it.
A little theory. Heat is a form of energy that is transferred between two systems due to temperature differences. In this case, thermal energy moves from a place with a high temperature to a place with a lower temperature. This is a natural process. Heat transfer can be carried out by conduction, thermal radiation or by convection.
There are three classical states of aggregation of matter, the transformation between which is carried out as a result of changes in temperature or pressure: solid, liquid, gaseous.
To change the state of aggregation, the body must either receive or give off thermal energy.
When melting (transition from solid to liquid), thermal energy is absorbed.
During evaporation (transition from liquid to gaseous state), thermal energy is absorbed.
During condensation (transition from a gaseous to a liquid state), thermal energy is released.
During crystallization (transition from a liquid to a solid state), thermal energy is released.
The heat pump uses two transition modes: evaporation and condensation, that is, it operates with a substance that is either in a liquid or gaseous state.
15. R410a refrigerant is used as the working fluid in the heat pump circuit. It is a hydrofluorocarbon that boils (changes from liquid to gas) at a very low temperature. Namely, at a temperature of 48.5 degrees Celsius. That is, if ordinary water at normal atmospheric pressure boils at a temperature of +100 degrees Celsius, then R410a freon boils at a temperature almost 150 degrees lower. Moreover, at very negative temperatures.
It is this property of the refrigerant that is used in the heat pump. By specifically measuring pressure and temperature, it can be given the necessary properties. Either it will be evaporation at ambient temperature, absorbing heat, or condensation at ambient temperature, releasing heat.
16. This is what the heat pump circuit looks like. Its main components are: compressor, evaporator, expansion valve and condenser. The refrigerant circulates in a closed circuit of the heat pump and alternately changes its state of aggregation from liquid to gaseous and vice versa. It is the refrigerant that transfers and transfers heat. The pressure in the circuit is always excessive compared to atmospheric pressure.
How it works?
The compressor sucks in the cold, low-pressure refrigerant gas coming from the evaporator. The compressor compresses it under high pressure. The temperature rises (heat from the compressor is also added to the refrigerant). At this stage we obtain a high pressure and high temperature refrigerant gas.
In this form, it enters the condenser, blown with colder air. The superheated refrigerant releases its heat to the air and condenses. At this stage, the refrigerant is in a liquid state, under high pressure and at an average temperature.
The refrigerant then enters the expansion valve. There is a sharp decrease in pressure due to the expansion of the volume occupied by the refrigerant. The decrease in pressure leads to partial evaporation of the refrigerant, which in turn reduces the temperature of the refrigerant below ambient temperature.
In the evaporator, the pressure of the refrigerant continues to decrease, it evaporates even more, and the heat necessary for this process is taken from the warmer outside air, which is then cooled.
The fully gaseous refrigerant enters the compressor again and the cycle is completed.
17. I'll try to explain again in a simpler way. The refrigerant boils already at a temperature of -48.5 degrees Celsius. That is, relatively speaking, at any higher ambient temperature it will have excess pressure and, in the process of evaporation, take heat from the environment (that is, street air). There are refrigerants used in low-temperature refrigerators, their boiling point is even lower, down to -100 degrees Celsius, but it cannot be used to operate a heat pump to cool a room in the heat due to the very high pressure at high ambient temperatures. R410a refrigerant is a balance between the ability of the air conditioner to operate for both heating and cooling.
By the way, here is a good documentary filmed in the USSR and telling about how a heat pump works. I recommend.
18. Can any air conditioner be used for heating? No, not just anyone. Although almost all modern air conditioners run on R410a freon, other characteristics are no less important. Firstly, the air conditioner must have a four-way valve, which allows you to switch to “reverse”, so to speak, namely, swap the condenser and evaporator. Secondly, note that the compressor (located on the bottom right) is located in a thermally insulated casing and has an electrically heated crankcase. This is necessary in order to always maintain a positive oil temperature in the compressor. In fact, at ambient temperatures below +5 degrees Celsius, even when turned off, the air conditioner consumes 70 watts of electrical energy. The second, most important point - the air conditioner must be inverter. That is, both the compressor and the impeller electric motor must be able to change performance during operation. This is what allows the heat pump to operate efficiently for heating at outside temperatures below -5 degrees Celsius.
19. As we know, on the heat exchanger of the external unit, which is an evaporator during heating operation, intensive evaporation of the refrigerant occurs with the absorption of heat from the environment. But in the street air there are water vapors in a gaseous state, which condense or even crystallize on the evaporator due to a sharp drop in temperature (the street air gives up its heat to the refrigerant). And intense freezing of the heat exchanger will lead to a decrease in the efficiency of heat removal. That is, as the ambient temperature decreases, it is necessary to “slow down” both the compressor and the impeller to ensure the most effective heat removal on the surface of the evaporator.
An ideal heating-only heat pump should have a surface area of the external heat exchanger (evaporator) several times larger than the surface area of the internal heat exchanger (condenser). In practice, we return to the same balance that a heat pump must be able to work for both heating and cooling.
20. On the left you can see the external heat exchanger almost completely covered with frost, except for two sections. In the upper, non-frozen section, freon still has a fairly high pressure, which does not allow it to effectively evaporate while absorbing heat from the environment, while in the lower section it is already overheated and can no longer absorb heat from the outside. And the photo on the right answers the question why the external air conditioner unit was installed on the facade, and not hidden from view on the flat roof. It is precisely because of the water that needs to be drained from the drain pan during the cold season. It would be much more difficult to drain this water from the roof than from the blind area.
As I already wrote, during heating operation at subzero temperatures outside, the evaporator on the external unit freezes over, and water from the street air crystallizes on it. The efficiency of a frozen evaporator is noticeably reduced, but the electronics of the air conditioner automatically monitors the efficiency of heat removal and periodically switches the heat pump to defrost mode. Essentially, the defrost mode is a direct air conditioning mode. That is, heat is taken from the room and transferred to an external, frozen heat exchanger to melt the ice on it. At this time, the fan of the indoor unit operates at minimum speed, and cool air flows from the air ducts inside the house. The defrost cycle usually lasts 5 minutes and occurs every 45-50 minutes. Due to the high thermal inertia of the house, no discomfort is felt during defrosting.
21. Here is a table of the heating performance of this heat pump model. Let me remind you that the nominal energy consumption is just over 2 kW (current 10A), and heat transfer ranges from 4 kW at -20 degrees outside, to 8 kW at an outside temperature of +7 degrees. That is, the conversion coefficient is from 2 to 4. This is how many times a heat pump allows you to save energy compared to the direct conversion of electrical energy into heat.
By the way, there is another interesting point. The service life of an air conditioner when operating for heating is several times higher than when operating for cooling.
22. Last fall, I installed a Smappee electric energy meter, which allows you to keep statistics of energy consumption on a monthly basis and provides a more or less convenient visualization of the measurements taken.
23. Smappee was installed exactly a year ago, in the last days of September 2015. It also tries to show the cost of electrical energy, but does so based on manually set tariffs. And there is an important point with them - as you know, we increase electricity prices twice a year. That is, during the presented measurement period, tariffs changed 3 times. Therefore, we will not pay attention to the cost, but will calculate the amount of energy consumed.
In fact, Smappee has problems with visualizing consumption graphs. For example, the shortest column on the left is consumption for September 2015 (117 kWh), because Something went wrong with the developers and for some reason the screen for the year shows 11 instead of 12 columns. But the total consumption figures are calculated accurately.
Namely, 1957 kWh for 4 months (including September) at the end of 2015 and 4623 kWh for the whole of 2016 from January to September inclusive. That is, a total of 6580 kWh was spent on ALL life support of a country house, which was heated year-round, regardless of the presence of people in it. Let me remind you that in the summer of this year I had to use a heat pump for heating for the first time, and it never worked for cooling in the summer in all 3 years of operation (except for automatic defrosting cycles, of course). In rubles, according to current tariffs in the Moscow region, this is less than 20 thousand rubles per year or about 1,700 rubles per month. Let me remind you that this amount includes: heating, ventilation, water heating, stove, refrigerator, lighting, electronics and appliances. That is, it is actually 2 times cheaper than the monthly rent for an apartment in Moscow of the same size (of course, without taking into account maintenance fees, as well as fees for major repairs).
24. Now let’s calculate how much money the heat pump saved in my case. We will compare electric heating, using the example of an electric boiler and radiators. I will calculate at pre-crisis prices that were at the time the heat pump was installed in the fall of 2013. Now heat pumps have become more expensive due to the collapse of the ruble exchange rate, and all the equipment is imported (the leaders in the production of heat pumps are the Japanese).
Electric heating:
Electric boiler - 50 thousand rubles
Pipes, radiators, fittings, etc. - another 30 thousand rubles. Total materials for 80 thousand rubles.
Heat pump:
Duct air conditioner MHI FDUM71VNXVF (external and internal units) - 120 thousand rubles.
Air ducts, adapters, thermal insulation, etc. - another 30 thousand rubles. Total materials for 150 thousand rubles.
Do-it-yourself installation, but in both cases the time is approximately the same. Total “overpayment” for a heat pump compared to an electric boiler: 70 thousand rubles.
But that's not all. Air heating using a heat pump is at the same time air conditioning in the warm season (that is, air conditioning still needs to be installed, right? That means we’ll add at least another 40 thousand rubles) and ventilation (mandatory in modern sealed houses, at least another 20 thousand rubles).
What do we have? The “overpayment” in the complex is only 10 thousand rubles. This is still only at the stage of putting the heating system into operation.
And then the operation begins. As I wrote above, in the coldest winter months the conversion factor is 2.5, and in the off-season and summer it can be taken to be 3.5-4. Let’s take the average annual COP equal to 3. Let me remind you that 6500 kWh of electrical energy is consumed in a house per year. This is the total consumption for all electrical appliances. For simplicity of calculations, let’s take the minimum that the heat pump consumes only half of this amount. That is 3000 kWh. At the same time, on average, he supplied 9,000 kWh of thermal energy per year (6,000 kWh was “brought” from the street).
Let's convert the transferred energy into rubles, assuming that 1 kWh of electrical energy costs 4.5 rubles (average day/night tariff in the Moscow region). We get 27,000 rubles in savings compared to electric heating only in the first year of operation. Let us remember that the difference at the stage of putting the system into operation was only 10 thousand rubles. That is, already in the first year of operation, the heat pump SAVED me 17 thousand rubles. That is, it paid for itself in the first year of operation. At the same time, let me remind you that this is not permanent residence, in which case the savings would be even greater!
But don’t forget about the air conditioner, which specifically in my case was not needed due to the fact that the house I built turned out to be over-insulated (although it uses a single-layer aerated concrete wall without additional insulation) and it simply does not heat up in the summer in the sun. That is, we will remove 40 thousand rubles from the estimate. What do we have? In this case, I began to SAVE on a heat pump not from the first year of operation, but from the second. It's not a big difference.
But if we take a water-to-water or even air-to-water heat pump, then the figures in the estimate will be completely different. This is why the air-to-air heat pump has the best price/efficiency ratio on the market.
25. And finally, a few words about electric heating devices. I was tormented with questions about all sorts of infrared heaters and nano-technologies that do not burn oxygen. I will answer briefly and to the point. Any electric heater has an efficiency of 100%, that is, all electrical energy is converted into heat. In fact, this applies to any electrical appliances; even an electric light bulb produces heat exactly in the amount in which it received it from the outlet. If we talk about infrared heaters, their advantage is that they heat objects, not air. Therefore, the most reasonable use for them is heating on open verandas in cafes and at bus stops. Where there is a need to transfer heat directly to objects/people, bypassing air heating. A similar story about burning oxygen. If you see this phrase somewhere in an advertising brochure, you should know that the manufacturer is taking the buyer for a sucker. Combustion is an oxidation reaction, and oxygen is an oxidizing agent, that is, it cannot burn itself. That is, this is all the nonsense of amateurs who skipped physics classes at school.
26. Another option for saving energy with electric heating (whether by direct conversion or using a heat pump) is to use the thermal capacity of the building envelope (or a special heat accumulator) to store heat while using a cheap nightly electric tariff. This is exactly what I will be experimenting with this winter. According to my preliminary calculations (taking into account the fact that in the next month I will pay the rural tariff for electricity, since the building is already registered as a residential building), even despite the increase in electricity tariffs, next year I will pay for the maintenance of the house less than 20 thousand rubles (for all electrical energy consumed for heating, water heating, ventilation and equipment, taking into account the fact that the temperature in the house is maintained at approximately 18-20 degrees Celsius all year round, regardless of whether there are people in it).
What's the result? A heat pump in the form of a low-temperature air-to-air air conditioner is the simplest and most affordable way to save on heating, which can be doubly important when there is a limit on electrical power. I am completely satisfied with the installed heating system and do not experience any discomfort from its operation. In the conditions of the Moscow region, the use of an air source heat pump is completely justified and allows you to recoup the investment no later than in 2-3 years.
By the way, don’t forget that I also have Instagram, where I publish the progress of work almost in real time -
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.
Among the main areas of development of engineering equipment for private households are increasing productivity with ergonomics and expanding functionality. At the same time, developers are increasingly paying attention to the energy efficiency of the technical equipment of communication systems. Heating infrastructure is considered the most expensive, so companies are showing special 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 heat air pumps
The main difference is the way the heat is generated. Most involve the use of traditional energy sources as a source. However, in the case of air pumps for both heating and hot water supply, most of the energy is consumed directly from natural resources. About 20% of the total potential is allocated for supply from conventional stations. Thus, air-heated houses use energy more economically and cause less damage to the environment. It is noteworthy that conceptual versions of the pumps were developed to supply office premises and enterprises. But later the technologies also covered the household equipment segment, allowing ordinary users to use profitable sources of thermal energy.
Principle of operation
The entire workflow is based on the circulation of refrigerant taken from the source. Heating occurs after condensation of air flows, which are compressed in the compressor. Next, the refrigerant in a liquid state goes directly into the heating system. Now we can take a closer look at the principle of coolant circulation in the pump design. In a gaseous state, the refrigerant is sent to a heat exchanger enclosed in the indoor unit. There it transfers heat to the room and turns into liquid. At this stage, the receiver comes into play, which is also supplied to the air source heat pump. The operating principle of the standard version of this device assumes that in this block the liquid will exchange heat with the refrigerant, which has 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. As the gaseous refrigerant passes through the pipe with reduced pressure in the receiver, its overheating 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 communication support for private homes if a power potential of more than 10 kW is required. As for the size of the pumps, they correspond to traditional air conditioners. Moreover, they can be confused in appearance with a split system. A standard block can have parameters of 90x50x35 cm. The weight also corresponds to typical climate control settings - on average 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 target and reaches an average of 30-40 °C. True, versions with combined functions are also available, which also cool the room.
Types of designs
There are several concepts for generating heat using an air pump. As a result, the design is tailored specifically to the needs of a specific generation scheme. The most popular model involves the interaction of air flows and a water carrier in one system. The main classification divides structures according to the type of organization of functional blocks. Thus, there is a heat air pump in a monoblock housing, and there are also models that provide for the system to be brought outside using an auxiliary segment. By and large, both models repeat the principle of operation of conventional air conditioners, only their functions and performance are raised to a new level.
Application of modern technologies
Innovative developments largely determined the development of classic climate control units. In particular, Mitsubishi uses a scroll compressor with two-phase refrigerant injection in its models, which allows the equipment to perform its function regardless of temperature conditions. Even at -15 °C, the heat air pump from Japanese developers demonstrates a performance of up to 80%. In addition, the latest models are equipped with new control systems, which ensure more convenient, safe and efficient operation of the installations. Despite all the technology of the equipment, the possibility of its integration into traditional heating systems with boilers and boilers remains.
Making your own air pumps
First of all, you need to purchase a compressor for future installation. It is fixed in the wall and performs the function of the outdoor unit of a conventional split system. Next, the complex is supplemented with a capacitor, which you can make yourself. This operation requires a copper “coil” about 1 mm thick, which must then be placed in a plastic or metal casing - for example, a tank or tank. The prepared tube is wound onto a core, which can be a cylinder with dimensions that allow it to be integrated into the tank. Using a perforated one, you can form turns at equal intervals, which will make the air more efficient; many home craftsmen do this with the subsequent injection of freon, which will act as a refrigerant. Next, the assembled structure is connected to the heating system of the house through an external circuit.
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A unit such as a heat pump has a similar operating principle to household appliances - a refrigerator and an air conditioner. It borrows approximately 80% of its power from the environment. The pump pumps heat from the street into the room. Its operation is similar to the principle of operation of a refrigerator, only the direction of transfer of thermal energy is different.
For example, to cool a bottle of water, people put it in the refrigerator, then the household appliance partially “takes” the heat from this object and now, according to the law of conservation of energy, must release it. But where? Everything is simple, for this purpose the refrigerator has a radiator, usually located on its back wall. In turn, the radiator, heating up, gives off heat to the room in which it stands. Thus, the refrigerator heats the room. The degree to which it warms up can be felt in small shops in the hot summer, when several refrigeration units are turned on.
And now a little imagination. Suppose that warm objects are constantly placed in the refrigerator, and it heats the room, or it is placed in a window opening, the freezer door is opened outward, and the radiator is in the room. During its operation, the household appliance, cooling the air outside, will simultaneously transfer the thermal energy that exists outside into the building. This is exactly the principle of operation of a heat pump.
Where does the pump get heat from?
The heat pump operates thanks to the exploitation of natural low-potential sources of thermal energy, including:- ambient air;
- bodies of water (rivers, lakes, seas);
- soil and ground artesian and thermal waters.
Heating system with heat pump
When a heat pump is used for heating, its operating principle is based on integration into the heating system. It consists of two circuits, to which is added a third, which is a pump design.
The coolant, which absorbs heat from the environment, circulates along the external circuit. It enters the pump evaporator and releases approximately 4 -7 °C to the refrigerant, despite the fact that its boiling point is -10 °C. As a result, the refrigerant boils and then goes into a gaseous state. The already cooled coolant in the external circuit is sent to the next turn to set the temperature.
The heat pump functional circuit consists of:
- evaporator;
- refrigerant;
- electric compressor;
- capacitor;
- capillary;
- thermostatic control device.
- After boiling, the refrigerant, moving through the pipeline, enters the compressor, which operates using electricity. This device compresses the gaseous refrigerant to high pressure, causing its temperature to rise;
- the hot gas enters another heat exchanger (condenser), in which the heat of the refrigerant is transferred to the coolant circulating through the internal circuit of the heating system, or to the air in the room;
- cooling, the refrigerant turns into a liquid state, after which it passes through the capillary pressure reducing valve, losing pressure, and then again ends up in the evaporator;
- thus, the cycle has ended and the process is ready to repeat.
Approximate calculation of heating output
Over the course of an hour, 2.5-3 cubic meters of coolant passes through the pump through the external collector, which the earth is able to heat by ∆t = 5-7 °C (read also: " "). To calculate the thermal power of a given circuit, you should use the formula:Q = (T 1 - T 2) x V, where:
V – coolant flow per hour (m 3 /hour);
T 1 - T 2 - temperature difference between inlet and inlet (°C).
Types of heat pumps
Depending on the type of dissipated heat consumed, heat pumps are:- ground-water - for their operation in a water heating system, closed ground contours or geothermal probes located at depth are used (more details: " ");
- water-water - the principle of operation in this case is based on the use of open wells for collecting groundwater and discharging it (read: " "). In this case, the external circuit is not looped, and the heating system in the house is water;
- water-air - install external water circuits and use air-type heating structures;
- air-to-air - for their operation, they use the dissipated heat of external air masses plus the air heating system of the house.
Advantages of heat pumps
- Cost-effective and efficient. The principle of operation of the heat pumps shown in the photo is based not on the production of thermal energy, but on its transfer. Thus, the efficiency of the heat pump must be greater than unity. But how is this possible? In relation to the operation of heat pumps, a value is used that is called the heat conversion coefficient, or abbreviated as CCT. The characteristics of units of this type are compared precisely according to this parameter.The physical meaning of the quantity is to determine the relationship between the amount of heat received and the energy expended to obtain it. For example, if the CPT coefficient is 4.8, this means that 1 kW of electricity expended by the pump produces 4.8 kW of heat, free of charge from nature.
- Universal universal application. If there are no power lines accessible to consumers, the pump compressor is operated using a diesel drive. Since natural heat is everywhere, the operating principle of this device allows it to be used everywhere.
- Environmental friendliness. The operating principle of the heat pump is based on low electricity consumption and the absence of combustion products. The refrigerant used by the unit does not contain chlorocarbons and is completely ozone-safe.
- Bidirectional mode of operation. During the heating season, the heat pump is able to heat the building and cool it in the summer. The heat taken from the room can be used to provide the house with hot water supply, and, if there is a swimming pool, to heat the water in it.
- Safe operation. There are no dangerous processes in the operation of heat pumps - there is no open fire, and substances harmful to human health are not released. The coolant does not have a high temperature, which makes the device safe and at the same time useful in everyday life.
- Automatic control of the room heating process.
The principle of operation of a heat pump, a fairly detailed video:
Some features of pump operation
To ensure efficient operation of the heat pump, a number of conditions must be met:- the room must be well insulated (heat loss cannot exceed 100 W/m²);
- It is advantageous to use a heat pump for low-temperature heating systems. The underfloor heating system meets this criterion, since its temperature is 35-40°C. The CPT largely depends on the relationship between the temperature of the input circuit and the output circuit.
The operating principle of heat pumps is to transfer heat, which allows you to obtain an energy conversion coefficient of 3 to 5. In other words, every 1 kW of electricity used brings 3-5 kW of heat into the house.
