The principle of operation of heat pumps. Heat pump installations

A heat pump is a whole heating system that can heat a private house no worse than the traditional heating we are used to. It is clear that in order to put the pump into operation, you first need to install it correctly.

All heat pumps, depending on which natural source they take heat from, are divided into three main types: ground-water, water-water, air-water.

Installation of each of these types has its own nuances and features. - a rather complex design and its installation is a laborious process, which must be approached with great responsibility. In the article we will consider what you need to pay attention to when installing various types of heat pumps.

Rules for installing a ground-to-water heat pump

Scheme of operation of the pump of the "soil-water" system (click to enlarge)

The ground is a source of heat. Having gone 5 meters into the ground, you can see that the temperature there remains almost the same all year round (in most regions of Russia it is 8-10°C).

Thanks to this, the heating will be highly efficient. The system works as follows: a ground heat exchanger located in the ground collects energy, which accumulates in the coolant, after which it moves to the heat pump and returns back.

Scheme of the pump of the "water-water" system (click to enlarge)

Part of the energy emitted by the sun remains underwater, especially in the water column. On the bottom of the reservoir or in the soil of the bottom are laid special pipes loaded with cargo.

The high temperature of the coolant in winter provides greater efficiency and heat transfer. But, alas, it is not suitable for installation in private homes.

More or less for small houses suitable option with a well. A special pump pumps water from the well to the evaporator, after which the water is drained into another well located downstream and deepened into the underground layer by 15 meters.

Expert advice: before using the water-water system, it is necessary to prevent debris from entering the evaporator and protect it from rust, as well as install a filter. If the water is rich in salts, then an intermediate heat exchanger with circulation in it is required pure water or antifreeze.

However, if the water from the well is poorly drained, a small flood and flooding of the pump is possible.

Rules for installing an air-to-water heat pump

Air-to-water pump operation diagram (click to enlarge)

Less popular than ground-water due to the fact that in winter it is impossible to take away enough heat from the air. -20°C - the limit of the heat pump, after which an additional heat generator comes into operation.

Basic installation schemes:

1. Monoblock structures are mounted indoors, all equipment is assembled in one case. A flexible air duct connects the mechanism to the street. External monoblocks are also made.
2. Split technology includes two blocks connected to each other.

One is located on the street, the other is in the building. In the first one, a fan with an evaporator is installed, and in the second - automation and a condenser. The compressor can be installed both indoors and outdoors.

Take note: When choosing air source heat pumps, keep in mind that when it gets cold, power is lost by almost half.

In the new heat pumps of this type, a function has been introduced that allows you to collect heat from the room, ventilation emissions and flue gases. Thanks to this, it is possible to heat the room and heat running water.

When buying a heat pump, you need to focus on the specific needs of your home.

Ideally, you need to know the heat loss of the house and the climate in which the dwelling is located. These data are important in order to choose the right heat pump power and model.

But you need to remember that, having selected a heat pump, you must also correctly select all the components of the heating system in which the heat pump will function.

It is impossible to find a universal heat pump, as each heating system is unique.
And yet, all heating systems with this device have common criteria that affect the heat pump connection scheme:

• the presence of an additional source of heat (heating boiler, solar battery, stove);
• the presence of water circuits (warm floor, fan coil units, radiators);
• the need for hot water supply;
• the presence of an air conditioner;
• the presence of a ventilation system;
• type of heat pump.

If you take into account these nuances and your individual needs, then you can make right choice and become the owner of a reliable, durable and economical heating system.

Watch the video, which shows the entire installation process of the heat pump:

One of the most popular types of equipment on the market climate technology Russia and the CIS are heat pumps. They are preferred by many buyers who want to create effective system cooling and heating their homes and offices, but very few people understand how this technique works and often do not even know in what situations it is best to use it. In the meantime, there are several basic questions regarding the operation of heat pump installations, and it will not be difficult even for beginners to understand them.

What are heat pumps?

This category of equipment includes equipment that is able to utilize the heat received from the environment, using a compressor to increase the temperature of the coolant to a predetermined level and then transfer heat to a certain room. At the same time, heat pumps can extract heat from any media, literally "pumping" it out of the environment. Thus, the pumps are able to work with:

• cold, frosty air
• cold water,
• earth.

By lowering the temperature of the coolant, such climate control equipment can effectively heat any building.

Specifications of the pump

In general, a heat pump unit, unlike other types of climate control equipment, consumes a minimum amount of electricity in the course of its work. On average, she needs to spend only 1 kW of energy, and this will be enough to produce 3-6 kW of heat. In other words, using the power of 2-3 ordinary light bulbs, in winter you can effectively heat a medium-sized living space.. In summer, the same power can be used to cool the room: in this case, the heat pump will absorb heat from the air in the room and discharge it into the atmosphere, into the ground or into the water, creating coolness in any room.

What are heat pumps?

There is a wide range of equipment on the market that can be used in various fields , including:

• Living spaces,
• agricultural enterprises,
• industrial enterprises,
• Department of Housing and Utilities.

Of course warmly pumping units for different rooms have different characteristics and may even vary in size. The pumps have different thermal power(from a few kW to hundreds of megaW), as well as can work with different heat sources, regardless of their state of aggregation (solid, liquid or gaseous). Given the characteristics of the operation of such equipment, Heat pump installations are divided into the following types:

• water-water,
• air-water,
• water-air,
• air-to-air,
• ground-water,
• soil-air.

There are also heat pumps on the market that are specially designed to work with low-grade heat. The sources of such heat can even have a negative temperature, and in this case the heat pump serves as a receiver of high-potential heat, which takes even a very high temperature (more than 1 thousand degrees). Generally, according to the temperature at which the installation works, it is divided into:

• low temperature
• medium temperature
• high temperature.

Another parameter by which heat pump installations are distinguished is related to their technical device. According to this indicator, the equipment is divided into such types as:

• absorption,
• vapor compression.

As a rule, all heat pumps, regardless of their type, work with electrical energy, but in certain cases they can be switched to other types of energy using a variety of fuels. According to the specifics of this fuel and the operation of the equipment itself, heat pump installations are divided into the following types:

• heating device that uses heat from ground water,
• pump for hot water supply, working with heat obtained from natural reservoirs,
• sea ​​water air conditioner
• air conditioning unit using outside air,
• pump for water heating in swimming pools, working outdoors,
• a heat pump unit for a heat supply system that utilizes the heat generated by engineering and technical equipment,
• a device that runs on milk - it serves to cool milk and subsequent hot water supply and is used on dairy farms,
• plant for the recovery of heat generated from technological processes, - serves to heat the supply air.

There are also other types of such equipment. At the same time, as a rule, heat pumps of any type are mass-produced, however, individual unique units can be manufactured according to exclusive projects. You can also find experimental heat pumps, many drawings that have not yet been implemented, and pilot models of such equipment, which can also be used in any special room.

All heat pump installations can be combined into a single system. This is necessary if several units of such equipment are operating at one facility, producing both heat and cold. Combining them together will only increase their effectiveness, and at medium or large facilities it is recommended to immediately plan the creation of such complex equipment.

What are Ring Air Conditioning Systems?

Such a system is completed on the basis of heat pumps different types, although an air-to-air unit is usually used for this purpose. The heat pump in this case serves as an air conditioner: it is installed directly in the refrigerated room, and the power of such equipment is selected in accordance with a number of parameters. Among them:

• the characteristics of the room itself,
• purpose of the premises,
• the number of people who are in it,
• equipment that is installed or will be installed in it.

Air conditioning units are always reversible - they both cool and generate heat at the same time. They are connected by a common water circuit - a pipeline through which water circulates, being both a source and a receiver of heat. As a result, the temperature inside the circuit can fluctuate within 18-32 degrees, and it is through it that heat is exchanged between the heat pumps that heat the air and between the equipment that cools it. If in different rooms need to create a climate different characteristics, heat pumps simply transfer heat from rooms that have an excess of it to rooms where there is not enough heat. This makes it possible to create an annular heat exchange between different zones, and such a system is very efficient and economical.

At the same time, ring systems can include not only air conditioning equipment, but also other installations. In particular, such devices can utilize waste heat. This is required where there are rather large heat requirements, for example:

• at facilities where there is an intense flow of wastewater: a water-to-water heat pump installation can easily utilize the heat emanating from it and direct it using a ring circuit for space heating;
• in facilities with exhaust ventilation that removes air from the building(provided that there are not too many impurities in the air that would make it difficult for the heat pump to work): in this case, an air-to-water installation will be needed, which will recover the heat from the "unnecessary" air and transfer it to space heating or water heating ,
• at facilities where there is both wastewater and exhaust ventilation- on them, ring systems can be used to remove excess heat from the water circuit (usually this is done only in the warm season), which will reduce the capacity of the cooling tower.

In any situation ring system allows you to use heat repeatedly and send it to the needs of absolutely all consumers in the building, and this is precisely its uniqueness, because traditional recuperators and regenerators are not capable of this. Moreover, such a system utilizes heat more efficiently, since its operation does not depend in any way on the temperature of the air that is taken in by the supply ventilation, and on the set temperature of the air that enters the premises.

In summer, the ring system, operating on the basis of a water-to-water heat pump unit, is able to effectively remove excess heat from the water circuit, utilizing it through consumers: excess heat is supplied to the hot water supply system, and it is usually enough to satisfy all the needs of the inhabitants of any room in hot water. Such a system will be especially effective at facilities with several swimming pools (holiday homes, hotels, health centers) - with its help, it will be possible to heat the water in the pools very quickly and at no extra cost.

Is the ring system compatible with other equipment systems?

Of course, yes, and above all it must be coordinated with the ventilation system. The latter, in particular, must be developed taking into account all the characteristics of the heat pump equipment that will condition the air. In particular, the ventilation system must necessarily ensure the recirculation of air in the volumes necessary for the stable operation of the pump, efficient heat recovery and maintaining the desired temperature in the room. This rule should be followed in all facilities, with the exception of some where recirculation is undesirable, such as swimming pools or kitchens.

At the same time, the advantage of matching the ring system with the ventilation system is that the latter in this case can be built according to a simpler scheme, which will cost the consumer less. In this case, the heat pump will cool the air directly where it is needed. This will save the consumer from the need to transport it through long heat-insulated air ducts and will favorably distinguish such a system from the now common centralized air conditioning.

Besides, ring systems can be coordinated with heating systems, and sometimes even completely take over their functions. In such situations, a heating system based on a heat pump becomes less powerful and simpler in terms of its equipment. This makes it particularly effective in cold climates where heating requires more heat obtained from high-potential sources. Furthermore, the ring system can seriously optimize the operation of all equipment in the room. Separate air conditioning and heating systems can seriously interfere with each other, especially when both are not required. The ring system completely excludes such a situation, since it always works effectively, based on the actual state of the microclimate created in each particular room. At the same time, at the enterprise, such equipment can cool and heat not only air, but also water, and this process will not require extra energy costs - it will be included in the balance of the entire heat supply as a whole.

And, of course, in any of these situations, the ring system will demonstrate excellent economy. In traditional systems, heat is used only partially and quickly escapes into the atmosphere if heating works in parallel with ventilation, however, the ring system solves this problem in a complex way, making heat recovery more efficient and significantly reducing its losses.

How to manage heat pump systems?

As a rule, this equipment does not require the installation of expensive tools. automated control and this is another "article" to save on it. Convenient automation here is extremely simple and comes down only to maintaining the set temperature of the water in the circuit. To do this, the system simply turns on an additional heater in time so that the water does not cool more than it should, or it activates the cooling tower so that it does not heat up more than necessary. And this is usually enough to maintain an ideal climate.

Implement automatic control in this situation is possible with just a few thermostats. Moreover, this does not even require precise control valves! The temperature of the water in the loop of the ring system can vary over a wide range without requiring any additional funds for this.

Besides, separate system automation also regulates the process of heat transfer by the heat pump to the consumer. It is built into the equipment itself, and one of the main elements of the system can be considered a thermostat (temperature sensor), which is installed directly in the room. It alone is enough to fully manage the operation of the heat pump installation. At the same time, the pump itself is able to provide all the necessary characteristics of the air temperature in the room without installing control dampers in the ventilation system, and control valves in the heating system. This allows you to further reduce the cost of the ring system and increase the reliability of all engineering communications of the building as a whole.

In general, a complex automated control system may be needed only at large facilities where many heat pumps of various types are installed, designed for air conditioning, technological processes and heat recovery. And in such situations, the installation of this system makes sense, because it allows you to optimize the operation of each piece of equipment. However, when installing it, it should be borne in mind that the operation of the ring system is influenced by a number of factors that even automation must “reckon with”. Among them:

• temperature of the water in the circuit, - it affects the heat conversion coefficient (the ratio of the amount of heat supplied to the consumer to the amount of energy consumed by the heat pump);
• outside air temperature;
• cooling tower operating parameters- it can expend a different amount of energy for the same amount of heat, and this depends on external conditions, including air temperature, presence of wind and other factors;
• the number of heat pumps that operate in the system, as well as their total capacity(the ratio of the power of the equipment that takes heat from the water circuit and the power of the installations that give it to the circuit).

Are there successful examples of using ring systems?

There are quite a few such examples, but the following two can be considered “textbooks”.

The first is the reconstruction of secondary school No. 2 in Ust-Labinsk. In this building, all the strictest sanitary requirements have been met in order to achieve maximum comfort for the children who will study in this institution. In accordance with these requirements, a special climate system was installed there, which is able to seasonally control temperature, humidity and inflow. fresh air. At the same time, the engineers did everything possible to ensure that each class had individual control over the microclimate, and only the ring system could cope with providing such control. She allowed:

• significantly reduce the cost of heating the entire building,
• solve the problem of cold water in the heating plant located on the school site.

The system was assembled from more than 50 Climatemaster heat pumps (USA) and one cooling tower. It receives additional heat from the heating plant, and it is controlled by automation, which independently maintains comfortable conditions for teaching children and at the same time works as economically as possible. It is thanks to her that the operation of the ring system, even in the most severe winter time, made it possible to reduce monthly heating costs to 9.8 thousand rubles: before the system was upgraded, the school spent 18 thousand 440 rubles every month on heating 2.5 thousand square meters. m. And this despite the fact that after the modernization, the heated area of ​​the school increased further, which amounted to 3 thousand square meters. m.

The second project was implemented in cottage villages near Moscow. The problems of building such settlements were often due to the fact that the infrastructure in these territories did not allow the construction of new houses, since neither water pipes nor Electricity of the net, nor transformer substations simply could not cope with the increased loads. At the same time, power outages, breaks in old wires, various accidents constantly occurred at old substations, so in the villages located in such territories, it was necessary to immediately take care of autonomous power supply.

Accordingly, the engineers needed to create a project that would allow two-storey cottage having several rooms with electricity and heat. The standard area of ​​such a house was 200 square meters. m, and only electricity and artesian water were connected to it, there were no other communications.

The first step the engineers took in the direction of energy efficiency - in the cottage were installed solar panels, and behind the house were installed photovoltaic modules, also powered by solar energy and with a capacity of 3.5 kW. This power was enough to feed the batteries, which subsequently powered the house itself and its heating system. Accordingly, electricity for a family living in such a cottage was free, which means that from family budget expenses could be deducted. As a result, the cost of installing batteries should pay off in less than 10 years, and after that no funds will need to be allocated.

For heating the cottage, a geothermal heat pump installation based on a water-to-water pump was used. It was designed not only for space heating with radiator batteries, but also for the production of hot water. A circuit that supplies low-grade heat to the pump - that is, an ordinary polyethylene pipe 800 m long and 32 mm in diameter - was laid on the site itself (at a depth of 2 meters). The installation of such a system (electricity + heating) was spent 40 thousand dollars, and given that in the future the owner will not have to spend money on paying for utilities supplied centrally, he only benefited from this.

Where can ring systems be used?

In general, all examples demonstrate that such heat pump installations can be mounted on a variety of objects. Among the main ones are:

• administrative buildings,
• medical and health institutions,
• public buildings,
• educational institutions,
• holiday homes and hotels,
• sport complexes,
• industrial enterprises,
• entertainment establishments.

At the same time, in any case, the flexible ring system can be easily adjusted to the needs of a particular room and mounted in the greatest variety of options.

To install it, engineers will need to take into account a number of nuances:

• needs for cold and heat at a particular facility,
• the number of people who are inside the premises,
• possible sources of heat in the building,
• possible heat sinks,
• features of heat loss and heat gain.

After that, the most best sources heat will be used in the system itself, and general power heat pumps must be configured so as not to be redundant.

On the whole, ideal option for any object, experts consider the installation of heat pump equipment that uses the environment both as a heat source and as its receiver. At the same time, the entire system should be balanced in terms of heat, regardless of the capacities of heat sources and receivers - they can be different, because their ratio changes when the operating conditions of the system change. However, they must be consistent with each other.

If these parameters are taken into account correctly, the ring system will effectively work both for heating and cooling, utilizing all the "excess" heat. And the use of one such system instead of several will not only create an ideal indoor climate, but will also be very efficient and profitable in terms of both capital and operating costs.

Heating your home with a heat pump will save you from energy slavery. By choosing this heating system, you will forever say goodbye to both unpredictable public utilities and voracious gas workers. That is, the temperature regime in the dwelling will be determined by you. And no one else.

Agree: only this fact makes a heat pump for heating a house a very profitable purchase. Yes, it's not cheap. But over time, all costs will pay off, and the fee for a "communal" or gas for an autonomous boiler will only increase. But you can make a heat pump with your own hands!

And in this article we will introduce you to the main types of heat pumps. We hope this information will help you choose (or build) the best power plant for heating your home.

Firstly, such pumps are very economical and efficient. You "invest" 0.2-0.3 kW of electricity used to power the compressor and receive 1 kW of thermal energy. That is, without taking into account the energy of air, water or soil, the efficiency of a heat pump is fantastic 300-500 percent.

Secondly, such pumps operate, in fact, a free and eternal source of energy - air itself, water or soil. Moreover, this "source" is ubiquitous. That is, heating country house A heat pump can be implemented anywhere - even at the equator, even beyond the Arctic Circle. True, in order to get close to such a "source" you need to use an energy-intensive compressor. But due to the unrealistically high efficiency, all energy costs pay off fivefold!

Thirdly, a heat pump is always individual. That is, you do not pay for excess energy. Your equipment will be configured for specific wishes and operating conditions.

Therefore, reviews of heat pumps for home heating are either favorable or the most enthusiastic.

In addition, the pump not only heats. In the warm season, it can also work as an air conditioner, cooling the home with the same efficiency.

Agree: all the above-mentioned advantages of a heat pump look somewhat fantastic. Especially efficiency at the level of 300-500 percent. However, all the advantages of thermal units are not fiction, but a reality that threatens energy companies.

The secret of such efficiency lies in the original principle of the pump, which, in summary, is as follows: the medium circulating through the pipes takes heat from a source with a low potential (air, soil, rocks, water) and dumps it at the point selected by the consumer.

That is, we have an “inverted” refrigerator in front of us: it takes heat from potential sources with the help of an evaporator and gives energy to the consumer through a condenser.

Moreover, both the heat pump and the refrigerator operate on a refrigerant - a substance with a very low boiling point, which is pumped through pipes using a special compressor.

Detailed scheme of work

As a result, upon closer examination, the scheme of operation of thermal units is as follows:

• At a depth of 5-6 meters in the ground, a cyclic pipeline with a coolant is installed, into which a special radiator is built - an evaporator. Moreover, this depth was not chosen by chance - at such a mark the temperature stays above zero at any time of the year.
• The evaporator is connected to a second pipeline filled with refrigerant. Under high pressure refrigerant boils even at one degree Celsius. Moreover, the evaporation process, as is known from the school physics course, is accompanied by the absorption of energy taken from the coolant circulating in the soil.
• The refrigerant vapors are pumped out of the pipeline by a compressor, which not only transports this medium through the fittings, but also generates even more pressure, which provokes additional heating of the refrigerant.
• Next, the superheated refrigerant vapors are pumped (by the same compressor) into the condenser, where the transformation of the aggregate state of the substance takes place (the vapor turns into a liquid). And all the same fundamentals of thermodynamics assert that when a gaseous medium condenses, energy is released.
• The released heat generated in the condenser is already absorbed by the third pipeline - the heating system of the dwelling. That is, the condenser acts as a gas or electric boiler. Well, returning to liquid state the refrigerant returns to the evaporator, passing through the regulating throttle.

Heat pumps for home heating: typical varieties

The most convenient way to classify heat pumps involves separating such units according to the type of medium in which the primary circuit is laid, supplying heat to the evaporator.

And according to this method of classification, heat pumps are divided into the following varieties:

• Geothermal units (land-water).
• Hydrothermal pumps (water-to-water).
• Aerothermal installations (air-water).

Moreover, all types of heat pumps operate general principle work, but the “habitat” of the primary circuit leaves its mark on both the functioning and the arrangement of the unit. Therefore, further in the text we will consider the nuances of arranging each type of heat pump.

Ground-to-water installation

Ground-to-water heat pump

The primary circuit of the geothermal pump is buried in the ground up to a mark of 5-6 meters. Moreover, such installation is practiced when arranging systems with a horizontal heat exchanger. And in the case of installing a vertical primary circuit, a 150-meter deepening is also practiced, in a special well.

At the same time, the minimum amount of work is typical for the vertical placement of the primary circuit. Since with horizontal placement it is necessary to distribute the heat exchanger tubes too large area (50 square meters for every 1000 watts of energy output from the heat pump).

Well, as a coolant, a geothermal heat pump uses a completely harmless brine solution that does not freeze even at low temperatures.

Water-to-water pump

The primary circuit of a hydrothermal pump can be installed in a natural or artificial body of water, a conventional or sewer well, a river or a man-made canal.

Heat pump "water-water"

Moreover, the evaporator and the pipe with the coolant are immersed in water by at least 1.5-2 meters. After all, the surface layers can freeze, damaging both the functionality and the integrity of the heat pump elements.

In a word, for a geothermal pump, you will have to choose the “right” reservoir. But the installation of the primary circuit itself is quite simple - a polymer pipe with the same brine is “drowned” at the desired depth, using special weights.

And this way of placing the primary circuit turns the arrangement pumping station"water-water" into an extremely simple and labor-intensive operation. Therefore, if there is a suitable reservoir nearby, then the best option The heat pump will be a hydrothermal unit.

Air-water unit

In fact, this is the same air conditioner, however, many large sizes. The primary circuit with the evaporator is placed "in the air", outside the dwelling, in a special building.

Moreover, to ensure the operation of the pump in winter, this housing is very often combined with an exhaust duct. ventilation system dwellings.

In a word, the main advantage of this system is ease of installation, but the efficiency of the air-to-water pumps is very doubtful. Well, in our latitudes, they simply cannot compete with geothermal or hydrothermal installations.

Do-it-yourself heat pump: is it possible?

Of course, yes! That's just the effectiveness of such a system will be practically unpredictable. After all, “factory” units are not only three compressors and the same number of pipelines through which the coolant and refrigerant circulate. The heart of such a heat pump is the control unit, which coordinates the operation of the first, second and third circuits of the entire system. And it is almost impossible to create such a control block “on your own”.

Well, the technical part of the pump is implemented very simply:

• An air conditioner unit can be used instead of a compressor.
• The primary circuit is assembled from polyethylene pipes and filled with a concentrated solution of common salt.
• The evaporator is a stainless steel metal tank (it can be removed from an old washing machine), into which the brine solution is lowered, giving off heat to the copper coil of the secondary circuit, mounted in inner part this tank.
• The condenser is exactly the same tank, only made of plastic, inside which the exact same copper coil is mounted. Moreover, the compressor pumps the refrigerant between the lower and upper coils.
• Well, the third circuit - the heating system - is connected to a polymer capacitor.

As you can see, everything is very simple. That's just the effectiveness of such a system can be both excessive and clearly insufficient.

Doctor of technical sciences V.E. Belyaev, chief designer of OMKB Horizon,
d.t.s. A.S. Kosoy, Deputy Chief Designer of Industrial Gas Turbine Units,
chief project designer,
Ph.D. Yu.N. Sokolov, head of the heat pump sector, OMKB Horizon,
FSUE MMPP Salyut, Moscow

The use of heat pump units (HPU) for energy, industry and housing and communal services is one of the most promising areas of energy-saving and environmentally friendly energy technologies.

A fairly serious analysis of the state and prospects for the development of work in this area was made at a meeting of the subsection "Heat supply and district heating" of the NTS of RAO "UES of Russia" on September 15, 2004.

The need to create and implement a new generation HPP is associated with:

♦ huge backlog Russian Federation and the CIS countries in the field of practical implementation of HPP, the ever-increasing needs of large cities, remote settlements, industry and housing and communal services in the development and use of cheap and environmentally friendly thermal energy (TE);

♦ the presence of powerful sources of low-potential heat (groundwater, rivers and lakes, thermal emissions from enterprises, buildings and structures);

♦ ever-increasing restrictions on the use of natural gas (GHG) for heat generating installations;

♦ opportunities to use progressive conversion technologies accumulated in aircraft engine building.

In the conditions of market relations, the most important technical and economic indicators of the efficiency of power generating plants are the cost and profitability of the energy produced (taking into account environmental requirements) and, as a result, the minimization of the payback period of power plants.

The main criteria for meeting these requirements are:

♦ Achieving the maximum possible fuel utilization factor (FUFR) in a power plant (ratio of useful energy to fuel energy);

♦ maximum possible reduction of capital costs and terms of power plant construction.

The above criteria were taken into account when implementing a new generation HPP.

First time for practical implementation For large-scale HPPs, it is proposed to use water vapor (R718) as a working fluid. The very idea of ​​using water vapor for HPP is not new (moreover, it was used by W. Thomson when demonstrating the efficiency of the first such real machine back in 1852 - ed.). However, due to the very significant specific volumes of water vapor at low temperatures(compared to traditional refrigerants), the creation of a real water vapor compressor for use in vapor compression HPPs has not yet been carried out.

The main advantages of using steam as a working fluid for HPP in comparison with traditional refrigerants (freons, butane, propane, ammonia, etc.) are:

1. Ecological cleanliness, safety and ease of technological maintenance, availability and low cost working body;

2. High thermophysical properties due to which the most expensive HPI elements (condenser and evaporator) become compact and cheap;

3. Significantly more high temperatures coolant to the consumer (up to 100 OS and above) compared to 70-80 OS for freons;

4. The possibility of implementing a cascade scheme for increasing the temperature from a low-potential source to a heat consumer (according to the Lorentz cycle) with an increase in the conversion factor in HPI (kHPU) compared to traditional ones by 1.5-2 times;

5. Possibility of generating chemically purified water (distillate) in HPP;

6. Possibility of using HPP compressor and condenser for:

♦ suction of water vapor from the outlet of heating turbines with the transfer of waste heat to the heat consumer, which additionally leads to an increase in the vacuum at the outlet of the turbine, an increase in its generated power, and a decrease in consumption circulating water, the cost of its pumping and thermal emissions into the atmosphere;

♦ suction of low-grade water vapor (waste) from energy technology installations

wok of chemical production, drying, etc. with the transfer of waste heat to the heat consumer;

♦ creation of highly efficient ejectors for steam turbine condensers, suction of multicomponent mixtures, etc.

Schematic diagram of HPI operation on water vapor and its design features

On fig. 1 shown circuit diagram HPI operation when using water vapor as a working fluid (R718).

A feature of the proposed scheme is the possibility of organizing the selection of heat from a low-temperature source in the evaporator due to the direct evaporation of a part of the water supplied to it (without heat exchange surfaces), as well as the possibility of transferring heat to the heating network in the HPI condenser both with and without heat exchange surfaces (mixing type ). The choice of the type of construction is determined by the binding of the HPI to a specific source of a low-potential source and the requirements of the heat consumer for the use of the coolant supplied to it.

For the practical implementation of a large-scale HPI on steam, it is proposed to use a commercially available aircraft axial compressor AL-21, which has the following important features when it is used to operate on steam:

♦ large volumetric productivity (up to 210,000 m3/h) with a compressor rotor speed of about 8,000 rpm;

♦ the presence of 10 adjustable steps to ensure efficient work compressor in various modes;

♦ Possibility to inject water into the compressor to improve efficiency, including power consumption reduction.

In addition, in order to increase the reliability of operation and reduce operating costs, it was decided to replace the rolling bearings with plain bearings, using instead of the traditional oil system water lubrication and cooling system.

To study the gas-dynamic characteristics of the compressor when operating on water vapor in a wide range of determining parameters, to develop structural elements and to demonstrate the reliability of the compressor under field test conditions, a large-scale test bench (closed type, diameter pipelines 800 mm, length about 50 m).

As a result of the tests, the following important results were obtained:

♦ the possibility of efficient and stable operation of the compressor on steam at n=8000-8800 rpm with a volume flow of steam up to 210 thousand m3/h was confirmed.

♦ the possibility of achieving a deep vacuum at the compressor inlet (0.008 ata) was demonstrated;

♦ the experimentally obtained compression ratio in the compressor πκ=5 exceeded by 1.5 times the required value for a HPI with a conversion ratio of 7-8;

♦ worked out robust design plain bearings of the compressor on the water.

Depending on the operating conditions of the HPI, 2 types of its layout are offered: vertical (HPU in one unit) and horizontal.

For a number of modifications of the proposed vertical layout of the HPI, it is possible to replace the tubular condenser with a spray-type condenser. In this case, the HPI working fluid condensate is mixed with the coolant (water) to the consumer. At the same time, the cost of HPP is reduced by about 20%.

The following can be used as a HPP compressor drive:

♦ built-in turbo drive with power up to 2 MW (for HPP with capacity up to 15 MW);

♦ remote high-speed turbo drives (for HPP with capacity up to 30 MW);

♦ gas turbine engines with utilization of fuel cells from the output;

♦ electric drive.

In table. 1 shows the characteristics of HPP on steam (R718) and freon 142.

When used as a low-grade source of heat with a temperature of 5-25 °C, for technical and economic reasons, freon 142 was chosen as the working fluid of the HPP.

Comparative analysis shows that for HPI running on water vapor, capital costs are between the water coolant and the working fluid (freon).

temperature range of the low-potential source:

♦ 25-40 OS - 1.3-2 times lower than for traditional domestic HPI on freon and 2-3 times lower than for foreign HPP;

♦ 40-55 OS - 2-2.5 times lower than for traditional domestic HPI on freon and 2.5-4 times lower than for foreign HPP.

Table 1. Characteristics of HPI on water vapor and freon.

*- when working on freon, the evaporator and condenser of HPP are made with heat exchange surfaces

**-T - turbo drive; G- gas turbine (gas piston); E - electric drive.

In the work under the conditions of actual operation of HPP at CHP, the possibility of efficient transfer of waste heat from steam turbine with HPI conversion factor equal to 5-6. In the proposed in and shown in Fig. 2, the HPI conversion coefficient will be significantly higher due to the exclusion of the HPI evaporator and, accordingly, the absence of a temperature difference between the low-temperature source and the working steam at the compressor inlet.

At present, the creation of highly efficient and environmentally friendly heat generating power plants based on HPP is extremely urgent task.

The results of the introduction of HPS are described in various types for the needs of heat supply, industrial enterprises and housing and communal services.

On the basis of real tests of HPI at CHPP-28 of OAO Mosenergo, 2 specific schemes for transferring waste heat to cooling towers with the help of HPI to the heating network (direct transfer to the return heating main and for heating the make-up network water).

The ways of creating high-performance compression heat pumps on water vapor when used as a low-grade heat source in the temperature range from 30 to 65 °C with a gas turbine drive of the compressor and utilization of the heat of exhaust gases from the gas turbine are analyzed. The results of the feasibility study showed that, depending on the conditions, the cost of heat generated by the HPP can be several times lower (and the KIT is several times higher) than with traditional heat generation at a CHP.

In the analysis of the effectiveness of the use of heat pumps in centralized hot water supply systems (DHW). It is shown that this efficiency significantly depends on the current tariffs for energy carriers and the temperature of the low-grade heat used, therefore, the problem of using HPI must be approached carefully, taking into account all specific conditions.

TNU as alternative source DHW consumers of district heating during the heating season

In this paper, based on the accumulated experience, the possibility and technical and economic indicators of a more in-depth compared to the use of heat pumps for hot water supply, in particular, almost 100% displacement of heat from traditional CHPPs for these purposes during the heating period, are analyzed.

For example, the possibility of implementing such an approach for the largest Moscow region of the Russian Federation is considered when two sources are used as waste heat:

♦ heat of natural water sources: Moscow rivers, lakes, reservoirs and others with an average temperature of about 10 °C;

♦ Waste heat from sewage and other sources;

♦ Waste heat to the cooling towers (from the outlet of the CHP steam turbines during the heating period in the ventilation pass mode with a steam temperature at the outlet of 30-35 °C). The total value of this heat is about 2.5 thousand MW.

Currently on DHW needs The Moscow region consumes about 5 thousand MW of heat (approximately 0.5 kW per 1 person). The main amount of heat for hot water supply comes from the CHPP through the district heating system and is carried out at the central heating station of the Moscow city heating network. Heating of water for hot water supply (from ~ 10 °C to 60 °C) is carried out, as a rule, in 2 heat exchangers 7 and 8 connected in series (Fig. 3), first from the heat of network water in the return heating main and then from the heat of network water in the direct heating main . At the same time, ~650-680 tce/h of SG is consumed for the needs of hot water supply.

The implementation of the scheme for the expanded (complex) use of the above sources of waste heat for hot water supply using a system of two HPPs (on freon and water vapor, Fig. 4) allows almost 100% compensation of about 5 thousand MW of heat during the heating period (respectively, to save a huge amount of GHG , reduce thermal and harmful emissions into the atmosphere).

Naturally, in the presence of operating CHPPs in the non-heating period of time, it is not advisable to transfer heat with the help of HPIs, since CHPPs, due to the lack of heat load, are forced to switch to the condensing mode of operation with the discharge of a large amount of heat from the burned fuel (up to 50%) into the cooling towers.

The heat pump unit HPU-1 with freon-based working medium (R142) can provide water heating from ~10 °C at the inlet to the evaporator 10 to ~35 °C at its outlet, using water with a temperature of about 10 °C as a low-temperature natural source with kHP of about 5.5. When used as a low-temperature source of waste water from industrial enterprises or housing and communal services, its temperature can significantly exceed 10 °C. In this case, kHNU will be even higher.

Thus, HPI-1 can provide 50% water heating for hot water supply with a total value of transferred heat up to 2.5 thousand MW and more with great efficiency. The scale of implementation of such HPI is quite large. With an average unit heat output of HPI-1 of about 10 MW, about 250 such HPIs would be required for the Moscow region alone.

When kHP=5.5, it is necessary to spend about 450 MW of electrical or mechanical power on the drive of HPP compressors (when driven, for example, from GTP). Heat pump units HPU-1 should be installed close to the heat consumer (at the central heating station of the city heating network).

Heat pump units HPP-2 are installed at the CHPP (Fig. 4) and used during the heating period as a low-temperature source of steam from the outlet of the heating turbines (ventilation passage of part low pressure(CHND)). At the same time, as noted above, steam with a temperature of 30–35 °C enters directly into compressor 13 (Fig. 2, there is no HPI evaporator) and, after its compression, is fed into condenser 14 of the HPI-2 heat pump unit to heat water from the return network line.

Structurally, steam can be taken, for example, through the safety (discharge) valve of the LPP of steam turbine 1. Compressor 13, creating a significantly lower pressure at the outlet of the LPP of turbine 1 (than in the absence of HPI-2), respectively, reduces the condensation (saturation) temperature of the steam and “turns off” the turbine condenser 3.

On fig. Fig. 4 schematically shows the case when waste heat is transferred by condenser 14 to the return heating main to PSV 4. In this case, even when all the waste heat is transferred from the output of the LPR of the turbine to the return heating main, the temperature in front of the PSV will increase by only ~5 °C, while slightly increasing the pressure of the heating steam from turbine extraction at PSV 4.

It is more efficient to first transfer part of the waste heat to heating the make-up network water (instead of its traditional heating with selective steam from the turbine), and then transfer the rest of the waste heat to the return heating main (this option is not shown in Fig. 4).

An important result of the proposed approach is the possibility of displacing up to 2.5 thousand MWFC (transmitted by peak hot water boilers). With a unit power of HPI-2 operating on water vapor equal to ~6-7 MW, 350-400 such units would be required to transfer such an amount of heat.

Given the very low level of temperature difference in HPI (~15 °C between the low-temperature source and the temperature of the return network water), the conversion factor of HPI-2 will be even higher (kHPI ~6.8) than for HPI-1. At the same time, in order to transfer ~2.5 thousand MWe to the heating network, it is necessary to spend a total of about 370 MW of electrical (or mechanical) energy.

Thus, in total, with the help of HPI-1 and HPI-2 during the heating season, up to 5,000 MW of heat can be transferred to the needs of the Moscow region's hot water supply. In table. 2 gives a technical and economic assessment of such a proposal.

As a drive for HPI-1 and HPI-2, a gas turbine drive with N=1 -5 MW and an efficiency of 40-42% (due to the heat recovery of exhaust gases) can be used. In case of difficulties associated with the installation of a GTP city heating network at the central heating station (additional SG supply, etc.), an electric drive can be used as a drive for HPI-1.

Technical and economic assessments were made for fuel and heat tariffs at the beginning of 2005. An important result of the analysis is a significantly lower cost of heat generated by HPP (for HPI-1 - 193 rubles/Gcal and HPI-2 - 168 rubles/Gcal ) in comparison with the traditional method of its generation at the CHPP of OAO Mosenergo.

It is known that at present the cost of fuel cells, calculated according to the so-called " physical way separation of fuel for the production of electricity and heat”, significantly exceeds 400 rubles/Gcal (heat tariff). With this approach, heat production even at the most modern thermal power plants is unprofitable, and this unprofitability is compensated by an increase in electricity tariffs.

In our opinion, this method of splitting fuel costs is incorrect, but it is still used, for example, in OAO Mosenergo.

In our opinion, given in table. 2 payback periods of HPP (from 4.1 to 4.7 years) are not large. When calculating, 5 thousand hours of HPP operation per year were taken. In reality, in summer period For some time, these units can operate, following the example of advanced Western countries, in the mode of centralized refrigeration, while significantly improving the average annual technical and economic performance.

From Table. It can be seen from Table 2 that the CIT for these HPPs varies in the range from ~2.6 to ~3.1, which is more than 3 times higher than its value for conventional CHPs. Taking into account the proportional reduction of thermal and harmful emissions into the atmosphere, the cost of pumping and the loss of circulating water in the system: turbine condenser - cooling tower, increasing the vacuum at the outlet of the LPP turbines (when HPI-2 is operating) and, accordingly, the generated power, technical and economic advantages this offer will be even more significant.

Table 2. Feasibility study for the use of HPP on water vapor and freon.

№	Name	Dimension	HP type
			TNU-1 on freon	TNU-2 on water vapor
1	Low temperature source temperature	°С	10	35
2	Temperature to consumer	°С	35	45-55
3	Q-gnu (single)	MW	10	6-7
4	Q HPU for hot water supply, total Q heat recovery from the output of GGU* Q total to the consumer	MW	2500 -450 -2950	2500 -370 -2870
5	kTNU	-	5,5	6,8
6	Total GTE power for compressor drive	MW	-455	-368
7	Total GHG consumption at the gas turbine engine of the compressor	τ c.e./h	140	113
8	Q fuel on GTE	MW	1138	920
9	WHALE	-	2,59	3,12
10	Specific cost of HPI construction with GTE drive	US$/kW thousand US$/Gcal	220 256	200 232
11	Total capital costs	USD million	-649	-574
12	Number of hours of use per year	h	5000
13	Costs per year, including: - fuel (1230 RUB/tce); - depreciation deductions(6.7%/year); - others (service, wage bill, etc.).	mln rub.	2450 862 1218 370	2070 695 1075 300
14	The cost of the entire volume of generated heat energy per year (400 rubles/Gcal or 344 rubles/MWh)	mln rub.	5070	4936
15	Fuel cost	RUB/Gcal	193	168
16	Profit per year	mln rub. USD million	2620 -94	2866 -102
17	Payback period (with return of depreciation charges)	in years	-4,7	-4,1

* - additional heat in the process of utilizing the heat of flue gases from gas turbine drive units can be used to displace part of the heat from the CHP plant to the district heating supply.

Taking into account the inevitable rise in energy prices upon Russia's accession to the WTO, restrictions on the use of GHG for energy and the need for the widespread introduction of highly efficient energy-saving and environmentally friendly energy technologies, the technical and economic benefits of introducing HPP will steadily grow.

Literature

1. A new generation of heat pumps for heat supply purposes and the efficiency of their use in a market economy // Materials of the meeting of the subsection of Heating and district heating of the NTS of RAO UES of Russia, Moscow, September 15, 2004

2. Andryushenko A.I. Fundamentals of thermodynamics of cycles of thermal power plants. - M.: Higher. school, 1985

3. Belyaev V.E., Kosoy A.S., Sokolov Yu.N. The method of obtaining thermal energy. Patent of the Russian Federation No. 2224118 dated July 5, 2002, FSUE MMPP Salyut.

4. Sereda S.O., Gel'medov F.Sh., Sachkova N.G. Estimated estimates of changes in the characteristics of a multistage

compressor under the influence of water evaporation in its flowing part, MMPP "Salyut"-CIAM // Thermal power engineering. 2004. No. 11.

5. Eliseev Yu.S., Belyaev V.V., Kosoy A.S., Sokolov Yu.N. Problems of creating a highly efficient vapor-compression plant of a new generation. Preprint of FSUE “MMPP “Salyut”, May 2005.

6. Devyanin D.N., Pishchikov S.I., Sokolov Yu.N. Development and testing at CHPP-28 of OAO Mosenergo of a laboratory stand for approbation of schemes for the use of heat pumps in the energy sector // Heat Supply News. 2000. No. 1. S. 33-36.

7. Protsenko V. P. On the new concept of heat supply to RAO UES of Russia // Energo-press, No. 11-12, 1999.

8. V. P. Frolov, S. N. Shcherbakov, M. V. Frolov, and A. Ya. Analysis of the efficiency of using heat pumps in centralized hot water supply systems // Energy Saving. 2004. No. 2.

Over the past year, heat pumps have occupied their niche in the Russian climate market, among other popular technologies. Discussion of the advantages and disadvantages of heat pump installations (HPU) took place both on the pages of the industry press and at thematic conferences and round tables. A lot of information has recently appeared about heat pumps - both in the Russian-language Internet and in specialized media. However, there are still very few publications on integrated heat pump systems. The purpose of this article is to somewhat fill this gap, to summarize some of the questions that arise in specialists when they first get acquainted with ring heat transfer systems, and to briefly answer them.

So, it is known about heat pumps that this is climatic equipment capable of utilizing the heat of the environment, using a compressor to raise the temperature of the coolant to the desired level and transfer this heat to where it is needed.

It is almost always possible to extract heat from the environment. After all, "cold water" is a subjective concept, based on our feelings. Even the coldest river water contains some heat. But it is known that heat passes only from a hotter body to a colder one. Heat can be forcibly directed from a cold body to a warm one, then the cold body will cool down even more, and the warm one will heat up. Using a heat pump, which "pumps out" heat from the air, river water or earth, lowering their temperature even more, it is possible to heat the building. In the classical case, it is considered that, spending 1 kW of electricity on operation, HPI can produce from 3 to 6 kW of thermal energy. In practice, this means that the power of two or three household light bulbs in winter can heat a medium-sized living room. In summer, by operating in reverse mode, the heat pump can cool the air in the rooms of the building. The heat from the building will be removed by being absorbed by the atmosphere, river or earth.

Currently, there is a huge variety of heat pump installations, which allows them to be widely used in industry, agriculture, in housing and communal services. As an example of the use of HPP, at the end of the article we will consider two projects - one of them is the project of a large-scale ring system implemented in Krasnodar Territory, the second is a small construction project in the Moscow region.

What are heat pumps?

Heat pumps come in a variety of heat outputs ranging from a few kilowatts to hundreds of megawatts. They can work with various sources heat in different states of aggregation. In this regard, they can be divided into the following types: water-water, water-air, air-water, air-air. Heat pumps are produced that are designed to work with sources of low-grade heat of various temperatures, up to negative. They can be used as a receiver of high potential heat requiring different temperatures, even above 1000C. Depending on this, heat pumps can be divided into low temperature, medium temperature and high temperature.

Heat pumps also differ in terms of technical device. In this regard, two directions can be distinguished: vapor compression and absorption HPP. Heat pumps can also use other types of energy for their work, in addition to electricity, for example, they can run on different types of fuel.

Various combinations of types of sources of low-grade heat and receivers of high-grade heat give a wide variety of types of heat pumps. Here are some examples:

• HPP, using the heat of groundwater for heating;
• HPP, using the heat of a natural reservoir for hot water supply;
• HPU - air conditioner using sea water as a source and receiver of heat;
• HPI - air conditioner using outside air as a source and receiver of heat;
• HPI for heating the water of the swimming pool, using the heat of the outside air;
• HPP, utilizing wastewater heat in the heat supply system;
• HPP, utilizing the heat of engineering and technical equipment in the heat supply system;
• HPP for cooling milk and at the same time heating water for hot water supply on dairy farms;
• HPP for heat recovery from technological processes in the primary heating of supply air.

A wide variety of heat pump equipment is mass-produced, but heat pumps can also be manufactured according to special projects. There are experimental installations, pilot samples, as well as many theoretical developments.

If the facility provides for the use of several heat pumps, which will be designed to produce both heat and cold, their efficiency will increase many times if they are combined into a single system. These are the so-called ring heat pump systems (KHNS). Such systems are expedient to use on average and large objects.

Ring air conditioning systems

These systems are based on water-air heat pumps that perform the functions of air conditioning in the premises. In the room where air conditioning is provided (or next to it), a heat pump is installed, the power of which is selected in accordance with the parameters of the room, its purpose, the characteristics of the required supply air - exhaust ventilation, the possible number of people present, the equipment installed in it and other criteria. All HPPs are reversible, that is, they are designed for both cooling and heating air. All of them are connected by a common water circuit - pipes in which water circulates. Water is both a source and a receiver of heat for all HPI. The temperature in the circuit can vary from 18 to 320C. Between heat pumps that heat the air and those that cool it, heat is exchanged through a water circuit. Depending on the characteristics of the premises, as well as on the time of year and time of day, either heating or cooling of the air may be required in different rooms. With simultaneous operation in the same building of HPI producing heat and cold, heat is transferred from rooms where it is in excess to rooms where it is not enough. Thus, there is an exchange of heat between the zones, united in a single ring.

In addition to HPP performing the function of air conditioning, HPP for other purposes may also be included in the HPP. If there are sufficient heat requirements at the facility, waste heat can be efficiently utilized through the ring system using HPI. For example, in the presence of an intensive wastewater flow, it makes sense to install a water-to-water HPI, which will allow waste heat to be utilized by means of a HPS. Such a heat pump will be able to extract heat from wastewater, transfer it using a ring circuit, and then use it to heat rooms.

The air removed from the building by exhaust ventilation also contains a large amount of heat. In the absence of a large amount of impurities in the exhaust air that impede the operation of the HPI, it is possible to utilize the heat of the exhaust air by installing an air-to-water HPI. Through CHP this heat can be used by all consumers in the building, which is difficult to achieve using traditional regenerators and recuperators. In addition, the recycling process in this case can be more efficient, since it does not depend on the temperature of the outside air taken in by the supply ventilation, and on the set temperature for heating the air injected into the premises.

In addition, when operating reversible heat pumps in both wastewater and exhaust ventilation, they can be used to remove excess heat from the water circuit during the warm season, and thereby reduce the required capacity of the cooling tower.

In the warm season, with the help of heat pumps, excess heat in the water circuit is utilized through consumers available at the facility. For example, a water-to-water HPI can be connected to the ring system, transferring excess heat to the hot water supply system (DHW). In a facility with a small need for hot water, this heat pump may be enough to fully satisfy them.

If the facility has one or more swimming pools, for example, in health care facilities, rest homes, entertainment complexes and hotels, the pool water can also be heated using a water-to-water heat pump by connecting it to the KTS.

Combination of ring systems with other systems

The ventilation system in buildings using an annular heat pump system must be developed taking into account the peculiarities of the operation of HPPs that condition air. It is obligatory to recirculate air in the amount necessary for the stable operation of these heat pumps, maintaining the set temperature in the room and efficient heat recovery (the exception is those cases where recirculation is undesirable, for example, swimming pool halls, local kitchen hoods). There are some other features in the development of ventilation with CTNS.

However, at the same time, the ring system provides for simpler ventilation systems than with other air conditioning methods. Heat pumps carry out air conditioning directly on site, in the room itself, which eliminates the need to transport the finished air through long, heat-insulated air ducts, as happens, for example, with central air conditioning.

The ring system can fully take over the functions of heating, but joint use with the heating system is not excluded. In this case, a less powerful and technically simpler heating system is used. Such a bivalent system is more suitable in northern latitudes, where more heat is needed for heating, and it will have to be supplied in larger quantities from a high-potential source. If a building has separate air conditioning and heating systems, these systems often literally interfere with each other, especially during transitional periods. The use of a ring system in conjunction with a heating system does not give rise to such problems, since its operation is completely dependent on the actual state of the microclimate in each individual zone.

At enterprises, ring heat pump systems can be involved in heating or cooling water or air for technological purposes, and these processes will be included in the balance of the general heat supply of the enterprise.

Speaking about traditional heat supply systems, it is difficult to agree with their limited efficiency. Heat is partially used, quickly dissipated into the atmosphere (during heating and ventilation), removed from sewage(through hot water supply, technological processes) and in other ways. It is also good if, for some economy, air-to-air heat exchangers are installed in the ventilation system, or water-to-water heat exchangers for heat recovery, for example, refrigeration units, or some other local heat recovery devices. KTNS, on the other hand, solves this problem in a complex manner, in many cases allowing to make heat recovery more efficient.

Automated control of ring systems

To the dismay of many manufacturers of expensive automation systems, heat pump systems do not require complex automation controls. All regulation here is reduced only to maintaining a certain value of the water temperature in the circuit. In order to prevent water from cooling below the set limit, it is necessary to turn on the additional heater in time. And vice versa, in order not to exceed the upper limit, it is necessary to turn on the cooling tower in a timely manner. Automatic management of this simple process can be implemented using several thermostats. Since the water temperature in the HPS circuit can vary over a fairly wide range (usually from 18 to 320C), there is also no need to use precise control valves.

As for the process of heat transfer from the heat pump to the consumer, it is controlled by the automation built into each heat pump. For example, HPI for air conditioning have a temperature sensor (thermostat) installed directly in the room. This ordinary thermostat is quite enough to control the operation of the HP.

The heat pump fully provides the necessary temperature parameters air in the premises, which makes it possible to refuse control dampers in the ventilation system and control valves in the heating system (with a bivalent system). All these circumstances contribute to reducing the cost and increasing the reliability of engineering systems as a whole.

At large facilities, where the ring system includes a large number of heat pumps and where various types of heat pumps are installed (for air conditioning, heat recovery and for technological processes), it often makes sense to implement more complex system automated control, which allows you to optimize the operation of the entire system.

The operation of an annular heat pump system is influenced by the following factors:

• Firstly, the temperature of the water in the circuit. The heat conversion coefficient (COP) depends on it, that is, the ratio of the amount of heat supplied to the consumer to the amount of energy consumed by the heat pump;
• secondly, the outside air temperature;
• thirdly, the operating parameters of the cooling tower. For the same amount of heat removed under different conditions, different amounts of energy consumed by the cooling tower can be expended. This, in turn, also depends on the temperature of the outside air, its humidity, the presence of wind and other conditions;
• fourthly, from the number of employees in this moment in the heat pump system. Here, the total power of the HPI, which take heat from the water circuit, is important in comparison with the power of all HPI, which transfer heat to the circuit, that is, the amount of heat entering the circuit or removed from it.

Good for the kids, good for the budget

Let's move on to the description of projects using ring heat pump systems.

The first project is the reconstruction of an ordinary general education school in the south of Russia. Last summer, the administration Krasnodar Territory implemented this project in Ust-Labinsk (city school No. 2). During the reconstruction, the highest standards were maintained in ensuring sanitary requirements and a comfortable stay for children at school. In particular, a full-fledged climate system was installed in the building, providing zone-by-zone control over temperature, fresh air inflow and humidity.

When implementing this project, engineers, firstly, wanted to ensure the proper level of comfort, individual control in each class. Secondly, it was assumed that the ring system would significantly reduce the cost of heating the school and solve the problem of low water temperature in the heating plant on the school site. The system consists of more than fifty heat pumps manufactured by Climatemaster (USA) and a cooling tower. It receives additional heat from the heating plant of the city. The climate system is under automated control and is able to independently maintain the most comfortable for a person and at the same time economical modes of operation.

The operation of the described system in the winter months gave the following results:

• before modernization (before the installation of heat pumps), the monthly heating costs for 2,500 m2 were 18,440 rubles;
• after the modernization of the building, the heated area increased to 3000 m2, and the monthly heating costs decreased to 9800 rubles.

Thus, the use of heat pumps made it possible to more than halve the cost of heating the building, the heated area of ​​which increased by almost 20%.

Autonomous heat

The problems of cottage construction in the Moscow region today are due to the fact that the infrastructure (electrical networks, water pipes) often does not allow new settlements to grow. The existing transformer substations cannot cope with the increased loads. Constant interruptions in the supply of electricity (accidents at old substations, breaks in dilapidated wires) force consumers to look for ways of autonomous power supply.

In the described project, the engineers were faced with the task of providing a multi-room two-story cottage with an attic with heat and electricity. The total heated area of ​​the house was 200 m2. Of the summed communications - artesian water and electricity.

Since the requirement of energy efficiency was put at the forefront, it was decided to install solar panels. 3.5 kW solar photovoltaic modules were purchased and installed right on the site behind the house. According to the calculations of the engineers, this should have been enough to recharge the batteries, which, in turn, would uninterruptedly feed the house and the heating system. The total cost of the system was about $27,000. If we take into account that a source of free electricity has been received, and this item will be crossed out from the family budget, it turns out that the cost of installing a solar battery will pay off in less than 10 years. And if we consider that otherwise we would have to build a substation or live with constant power outages, then the costs can already be considered paid off.

For heating, it was decided to use a geothermal heat pump system. An American water-to-water heat pump was purchased. This type of heat pumps with the help of heat exchangers produces hot water, which can be used for hot water supply and heating using radiator batteries. The circuit itself, supplying to heat pump low-grade heat was laid directly on the site adjacent to the cottage, at a depth of 2 m. The circuit is a polyethylene pipe with a diameter of 32 mm and a length of 800 m. Installation of a heat pump with installation, supply of equipment and components cost 10,000 US dollars.

Thus, having spent about 40,000 US dollars on organizing his own autonomous energy system, the owner of the cottage excluded the cost of heat supply from his budget and provided reliable autonomous heating.

Possibilities of application of ring systems

From the foregoing, it follows that the possibilities of using an annular heat pump system are unusually wide. They can be used on a wide variety of objects. These are administrative, public buildings, medical and health institutions, rest houses, entertainment and sports complexes, various industrial enterprises. The systems are so flexible that their application is possible in a variety of cases and in a very large number of options.

When developing such a system, first of all, it is necessary to assess the needs for heat and cold of the object being designed, to study all possible heat sources inside the building and all prospective heat receivers, to determine heat gains and heat losses. The most suitable heat sources can be used in the ring system if this heat is required. The total capacity of the heat recovery heat pumps should not be needlessly redundant. Under certain conditions, the most profitable option may be the installation of HPPs that use the external environment as a source and receiver of heat. The system must be balanced in terms of heat, but this does not mean at all that the total capacities of heat sources and consumers should be equal, they can differ, since their ratio can change significantly when the operating conditions of the system change.

How to deal with the fire hazard of air ducts

Recently, the number of fires and even explosions inside the air ducts of ventilation and air conditioning systems has sharply increased. Despite the fact that such fires have always occurred, the changes that have occurred in recent times, caused much larger fires involving more people.

Analysis of advanced heat supply systems

This report discusses issues related to the transition of district heating systems to decentralized. The positive and negative aspects of both systems are considered. The results of the comparison of these systems are presented.