Types of heat pump installations. Complex application of heat pump installations

Question 26. Beneficial use of low-potential energy resources. Heat pump installations

Recently, a real opportunity has appeared to solve the issues of integrated energy supply in a fundamentally new way. industrial enterprises through the use of heat pumps that use low-grade emissions to generate both heat and cold. The simultaneous production of these energy carriers by heat pumps is almost always more efficient than the separate production of heat and cold in traditional plants, since in this case the irreversible losses of the refrigeration cycle are used to generate heat that is given to the consumer.

In heat pump installations, the temperature of the heat sink is equal to or slightly higher than the ambient temperature, and the temperature of the heat receiver is much higher than the ambient temperature, i.e. T n >T about. Heat pumps are devices that transfer energy in the form of heat from a lower to a higher temperature level required for heat supply. The main purpose of these installations is to use the heat of low-potential sources, such as the environment.

Currently, three main groups of heat pumps have been developed and are being used: compression (steam); jet (ejector type); absorption.

Compression heat pumps used for heating individual buildings or groups of buildings, as well as for the heat supply of individual industrial workshops or installations.

Freons are usually used as a working agent in heat pump installations.

Figure 4 shows circuit diagram ideal vapor pressure heat pump. Available low-potential heat at temperature Tn is supplied to evaporator I. Vapors of the working agent come from the evaporator I to the compressor II in state 1 and are compressed to a pressure pk and the corresponding saturation temperature Tk. In state 2, the compressed vapors of the working agent enter condenser III, where they transfer heat to the heat carrier of the heat supply system. In the condenser, the vapors of the working agent are condensed. From the condenser, the working agent enters in liquid form into the expander IV (a device in which the expansion of the working fluid, produced together with cooling, occurs with the performance of useful work), where the working agent expands from pressure p to pressure p o, accompanied by a decrease in its temperature and heat transfer. From the expander, the working agent enters the evaporator I and the cycle is closed.

The scheme of heat pumps operating in a closed cycle is fundamentally no different from the scheme of steam compression refrigeration units. However, the connection of consumers is carried out in different ways. In refrigeration circuits, the cold consumer is connected to the evaporator, and in heat pump systems, the heat consumer is connected to the condenser.

Heat pumps belong to heat transformation plants, which also include refrigeration ( 120 K), cryogenic ( = 0 ... 120 K) and combined ( , ) plants. All these installations operate according to reverse thermodynamic cycles, in which, with the expenditure of external work, thermal energy is transferred from bodies with a low temperature (heat sinks) to bodies with a high temperature (heat receivers). But if the function of refrigeration and cryogenic installations is to cool bodies and maintain a low temperature in the refrigeration chamber, i.e. heat removal, the main function of heat pumps is to supply heat to a high-temperature source using low-temperature thermal energy. At the same time, it is advantageous that the amount of high-temperature heat obtained can be several times higher than the work expended.

The heat transformer can operate simultaneously as a refrigeration and heat pump unit; while T n< Т о и Т н >That. Such a process is called combined. In the combined process, heat and cold are generated simultaneously - medium A is cooled and medium B is heated. Thus, in refrigeration units, artificial cooling of bodies is carried out, the temperature of which is lower than the ambient temperature. In heat pump installations, the heat of the environment or other low-potential environments is used for heat supply purposes.

Ideal Cycles Carnot installations heat transformations are shown in Fig.5.

Efficiency refrigeration machines( - useful effect, the amount of heat taken from a colder coolant) is estimated by the coefficient of performance. For a heat pump, the concept of transformation ratio is used ( - useful effect, the amount of heat given to the heated coolant) or heating coefficient, i.e. the amount of heat produced per unit of work expended.

, ,

, .

For real heat pumps = 2 - 5.

A real installation has losses caused by the irreversibility of the compression (internal) and heat exchange (external) processes. Internal irreversibility is due to the viscosity of the refrigerant and the release of heat of internal friction during compression in the compressor (entropy increases). The actual work of compression, where - perfect job in a reversible process; - relative internal efficiency of the compressor; - electromechanical efficiency of the drive.

External irreversibility is explained by the need to have a temperature difference for the occurrence of heat transfer, which is set (determined) by the area of ​​the heat exchange surface at a given heat flux.

That's why ,

where , - temperatures respectively in the evaporator and condenser of the installation.

Jet heat pumps of ejector type are currently widely used. High-pressure steam enters the jet apparatus, and due to the use of the energy of the working flow, the injected flow is compressed. A mixture of two streams comes out of the apparatus. Thus, when the injected vapor is compressed, its temperature simultaneously rises. The compressed steam stream is then withdrawn from the plant.

High-pressure steam with parameters p p and T p enters the jet apparatus (Fig. 6). Due to the use of the energy of the working flow, the injected flow is compressed with the parameters r n and T n. A mixture of streams with parameters comes out of the apparatus r s and T s. Thus, when the injected vapor is compressed, its temperature (and, consequently, the enthalpy) also increases. The compressed steam stream is then withdrawn from the plant. Pressure ratio r s / r n in such devices, called jet compressors, is relatively small and is within 1.2 ≤ r s / r n≤ 4.

Jet heat pumps are currently the most widely used due to ease of maintenance, compactness, and the absence of expensive elements.

Absorption heat pumps work on the principle of absorption of water vapor by aqueous solutions of alkalis (NaOH, KOH). The process of absorption of water vapor occurs exothermically, i.e. with heat release. This heat is spent on heating the solution to a temperature significantly higher than the temperature of the absorbed vapor. After leaving the absorber, the heated alkali solution is directed to a surface evaporator, where secondary steam is generated at a higher pressure than the primary steam entering the absorber. Thus, in absorption heat pumps, the process of obtaining high-pressure steam is carried out by using heat supplied from outside.

A schematic diagram of an absorption heat pump is shown in Fig. 7.

As a working substance in absorption heat pumps, a solution of two substances (binary mixture) is used, which differs in boiling point at the same pressure. One substance absorbs and dissolves the second substance, which is a working agent. The working cycle of an absorption heat pump is as follows. In the evaporator 3, through the walls of the heat exchanger, low-potential heat is supplied to the binary solution at a temperature Tо. The supplied heat ensures the evaporation of the working agent from the binary mixture at a pressure p o. The resulting vapors of the working agent from the evaporator through the pipeline enter the absorber 2, where they are absorbed by the solvent (absorbent), and the heat of absorption Q a is released. The strong liquid solution formed in the absorber is pumped by pump 1 to generator 6. The heat Q g spent on the evaporation of the working agent at high pressure p k, and, accordingly, high temperature T k, is supplied to the generator. becomes weak. A weak solution is sent through the pipeline to the absorber 2, lowering the pressure in the auxiliary thermostatic valve 7 to the pressure in the evaporator p about. The working agent vapor formed in the generator enters the condenser 5, where, through the separating wall, they give off the heat of condensation Q k at a high temperature T k. The working agent condensed in the condenser lowers the pressure in the thermostatic valve from p to p o, with which it enters the evaporator. Then the process is repeated.

The operation of an ideal absorption heat pump is characterized by the following heat balance equation:

where Q n- the amount of heat of low potential, summed up in the evaporator;

Q g - the amount of high potential heat supplied to the generator;

Q us - heat equivalent to pump operation;

Q to- the amount of high potential heat removed in the condenser;

Q a - the amount of low potential heat removed in the absorber.

The working agent is usually water and the absorbent is lithium bromide.

For chemical, petrochemical and oil refineries that have a large volume of water for cooling technological units, the temperature of which is in the range from 20 to 50 ° C, it is necessary to use absorption lithium bromide heat pumps, which will operate in cooling mode in summer recycled water, and in winter, use the waste heat of circulating water to generate hot water for heating workshops. Table 6 shows the parameters of absorption lithium bromide heat pumps (ABTN).

Absorption heat pumps are highly efficient, have no moving parts and can be easily manufactured. However, absorption pumps require a high specific metal consumption, which makes them bulky. The possibility of metal corrosion requires the manufacture of equipment from alloyed steel. Therefore, absorption heat pumps are not widely used in industry.

Table 6

ABTN parameters

Working agents and coolants (coolants)

in heat transformers

For the implementation of processes in heat transformers, working substances (agents) are used that have the necessary thermodynamic, physicochemical properties. They can be homogeneous or are a mixture of several, usually two, substances. In most heat transformers, the working substances undergo phase transformations. Currently, the following working substances are used in heat transformers:

a) refrigerants - substances having a low boiling point at atmospheric pressure from +80 to -130 ° C. Refrigerants with a boiling point from +80 to -30 °C are usually used in heat pump installations, and with lower boiling points from 0 to -130 °C - in moderate cold installations;

b) gases and gas mixtures (also air) with low boiling points;

c) working agents and absorbents of absorption plants;

d) water used for its thermophysical properties in refrigeration plants, where the temperature of the lower source, heat tn> 0 ° C, for example, for air conditioning.

For economical and safe operation of heat transformers, refrigerants must meet the following requirements:

a) have a low overpressure at the boiling and condensing temperatures, a large heat output of 1 kg of the agent, a small specific volume of steam (for reciprocating compressors), a low heat capacity of the liquid and high thermal conductivity and heat transfer coefficients;

b) have a low viscosity, possibly a lower solidification point, do not dissolve in oil (for reciprocating compressors);

c) be chemically resistant, non-flammable, non-explosive, non-corrosive to metals;

d) be harmless to the human body;

e) be non-scarce and inexpensive.

The working agents of gas refrigeration units must have a low normal temperature boiling, low viscosity, high thermal conductivity and heat capacity Ср, which depends little on temperature and pressure.

The working agents of absorption plants, in addition to meeting the above requirements, must be well absorbed and desorbed in combination with appropriate sorbents.

The economic efficiency of heat pumps depends on:

The temperatures of a low-potential source of thermal energy will be the higher, the higher the temperature it will have;

The cost of electricity in the region;

The cost of thermal energy produced using various types of fuel.

The use of heat pumps instead of traditionally used sources of thermal energy is economically beneficial due to:

No need to purchase, transport, store fuel and spend money associated with it;

The release of a large area necessary for the placement of a boiler house, access roads and a fuel warehouse.

The greatest energy saving potential exists in the area of ​​heat supply: 40-50% of the country's total heat consumption. The equipment of existing CHPPs is physically and morally worn out, operated with excessive fuel consumption, heating network are the source big losses energy, small heat sources are characterized by low energy efficiency, a high degree of environmental pollution, increased unit costs and labor costs for maintenance.

TNU provide an opportunity to:

1) minimize the length of heat networks (approximate thermal power to places of consumption);

2) receive in heating systems 3 - 8 kW of equivalent thermal energy (depending on the temperature of the low-potential source, while spending 1 kW of electricity).

To date, the scale of introduction of heat pumps in the world is as follows:

In Sweden, 50% of all heating is provided by heat pumps; in recent years alone, more than 100 (from 5 to 80 MW) heat pump stations have been commissioned;

Germany provides for a state subsidy for the installation of heat pumps in the amount of DM 400 for each kilowatt of installed capacity;

In Japan, about 3 million heat pumps are produced annually;

In the USA, 30% of residential buildings are equipped with heat pumps, about 1 million heat pumps are produced annually;

In Stockholm, 12% of the entire heating of the city is provided by heat pumps with a total capacity of 320 MW, using the Baltic Sea as a heat source with a temperature of + 8 ° C;

In the world, according to the forecasts of the World Energy Committee, by 2020 the share of heat pumps in heat supply (municipal sector and production) will be 75%.

The reasons for the mass acceptance of heat pumps are as follows:

Profitability. To transfer 1 kW of thermal energy to the heating system, the heat pump needs only 0.2 - 0.35 kW of electricity;

Ecological purity. The heat pump does not burn fuel and does not produce harmful emissions into the atmosphere;

Minimum Maintenance . Heat pumps have a long service life before overhaul (up to 10 - 15 heating seasons) and operate fully automatically. Maintenance of installations is seasonal technical inspection and periodic monitoring of the operating mode. To operate a heat pump station with a capacity of up to 10 MW, more than one operator per shift is not required;

Easy adaptation to the existing heating system;

Short term payback . Due to the low cost of the heat produced, the heat pump pays off in an average of 1.5 - 2 years (2 - 3 heating seasons).

Now there are two directions of TNU development:

Large heat pump stations (HPS) for district heating, including steam compression HPI and peak hot water boilers used at low air temperatures. The electrical (consumed) power of the HPI is 20 - 30 MW, the thermal power is 110 - 125 MW. Compared to conventional boilers, fuel savings of 20 - 30% are achieved, air pollution is reduced (no boilers!);

Decentralized individual heat supply (low-power vapor compression heat pumps and thermoelectric semiconductor heat pumps). Fuel economy compared to small boiler houses is 10 - 20%. Refrigeration possible. Accompanied by high unit costs fuel, investment and labor costs.

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 that "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, 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 an object of small construction 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 heat sources 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, 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;
• HPI-air conditioner using sea water as a source and receiver of heat;
• HPU-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 industrial 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 exhaust air a large number impurities that hinder the operation of the HPI, it is possible to utilize the heat of the removed 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 little 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 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 KTN.

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 volume that is 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 for 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 operation), removed with wastewater (through hot water supply, technological processes) and in other ways. It is also good if, to provide some efficiency, 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 making it possible 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 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 control 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 of the 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 cost reduction and reliability increase. engineering systems generally.

At large facilities where the ring system includes a large number of heat pumps and where various types of HPPs 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 affected 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, on the number of heat pumps currently working in the 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 a conventional secondary 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, inflow fresh air 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 ( Electricity of the net, water pipes), often prevents the growth of new settlements. 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-storey cottage with attic heat and electricity. The total heated area of ​​the house was 200 m2. From the failed 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. Given that the received source free electricity, and this article will be deleted from 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 low-grade heat to the heat pump, was laid directly on the site adjacent to the cottage, at a depth of 2 m. The circuit is 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 costs 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 sport 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 HPP using external environment as a source and receiver of heat. The system must be heat balanced, but this does not mean at all that total capacities heat sources and consumers must be equal, they may differ, since their ratio can change significantly when the operating conditions of the system change.

Thus, the ring heat pump system performs the functions of both heating and air conditioning, and efficient heat recovery. The use of one system instead of several is always more profitable in terms of capital and operating costs.

Article provided by the company "AEROCLIMATE"

Usage: in installations for heating and cooling rooms with permanent ventilation. The essence of the invention heat pump installation contains a heat exchanger 1, an evaporator 4, an injector-absorber 6, a pressure-separating tank 9 and a liquid pump 7. The evaporator 4 and the injector-absorber 6 are connected by at least one capillary 5. The evaporator 4 is made of three cavities and is filled with a porous body 16. 5 z.p. f-ly, 2 ill.

The invention relates to heat pump installations based on absorption units, in particular to installations for heating and cooling rooms with permanent ventilation. The operation of all heat pumps is based on the thermodynamic state and the parameters that determine this state: temperature, pressure, specific volume, enthalpy and entropy. All heat pumps work by supplying heat isothermally at low temperatures and isometrically dissipating at high temperatures. Compression and expansion is performed at constant entropy, and the work is done from an external engine. A heat pump can be described as a heat multiplier that uses low-grade heat from various heat-producing media such as ambient air, soil, groundwater, wastewater, etc. Currently, there are many different heat pumps with different working fluids. This diversity is caused by the existing restrictions on the use of one or another type of heat pump, which are imposed not only by technical problems, but also by the laws of nature. The most common are pumps with mechanical vapor compression, followed by absorption cycle and double Rankine cycle pumps. Pumps with mechanical compression are not widely used due to the need for dry steam, which is caused by the mechanics of most compressors. The ingress of liquid along with steam to the compressor inlet can damage its valves, and the flow of a large amount of liquid into the compressor can generally disable it. The most widely used pumps are absorption type. The process of operation of absorption plants is based on the successive implementation of thermochemical reactions of absorption of the working agent by the absorbent, and then the release (desorption) of the absorbent from the working agent. As a rule, a working agent in absorption plants water or other solutions that can be absorbed by the absorbent serve as absorbents, compounds and solutions that easily absorb the working fluid can be used: ammonia (NH 3), sulfuric anhydrite (SO 2), carbon dioxide (CO 2), caustic soda (NaOH) , caustic potash (KOH), calcium chloride (CACl 2), etc. Known, for example, is a heat pump unit (ed. St. USSR N 1270499, class F 25 B 15/02, 29/00, 1986), containing an absorption refrigeration unit with a refrigerant circuit, a condenser, a subcooler, an evaporator, a dephlegmator and a regenerative heat exchanger, as well as the heating water circuit passing through the condenser, the ventilation air line passing successively through the absorber and the subcooler, the heating water circuit is made closed and a dephlegmator is additionally included in it. The plant additionally contains a two-cavity heat exchanger - subcooler, which is connected by one cavity to the refrigerant circuit between the subcooler and the evaporator, and the other - to the ventilation air line in front of the absorber. The described installation is cumbersome and metal-intensive, as it has components and systems operating at elevated pressure. In addition, the achievement of high energy performance in the known plant uses ammonia and its aqueous solutions, which are toxic and corrosive, as a coolant. The most efficient heat pump installations are of the absorption-injector type. Known thermal installation (ed. St. USSR N 87623, class F 25 B 15/04, 1949), including an ammonia steam generator (evaporator) filled with a highly concentrated water-ammonia solution, with a coil of steel pipes located inside it, into which steam is supplied low-pressure, used to evaporate ammonia, high-pressure absorbers (injectors), pumps, tubular heat system, high steam generator, low-pressure steam condensate heater, cooler, which simultaneously serves as a heater. The described installation makes it possible to increase the steam pressure at a high value of thermal efficiency due to the fact that the absorber of the installation has injectors that serve to increase the pressure obtained in the ammonia vapor generator with the help of a lean solution supplied by a pump from the generator. However, in the described installation, aggressive media are used, which requires the use of special materials of high corrosion resistance. This greatly increases the cost of installation. The aim of the invention is to create a simplified, environmentally friendly, economical installation with high energy performance. This problem is solved by the fact that a heat pump installation containing a heat exchanger, an evaporator, an injector-absorber, a liquid pump, a pressure-separating tank, an evaporator and an injector-absorber, which, according to the invention, are interconnected by at least one capillary, and the evaporator is made of three-cavity, one cavity of which is connected to the heat exchanger by a ventilation air line, the other is filled with a coolant, separated by a vacuum cavity connected to an injector-absorber, and the evaporator contains a porous body placed simultaneously in all these cavities. The design of the connection between the evaporator and the injector-absorber in the form of a thermodynamically discontinuous system connected by at least one capillary makes it possible to conduct the process of obtaining heat in a region far from thermodynamic equilibrium, which significantly intensifies heat and mass transfer in the system under consideration. It is possible to connect the evaporator and the injector-absorber with several capillaries. This will enhance the effect of heat and mass transfer in the system under consideration. The execution of the evaporator with three independent, separated cavities and with a porous body placed simultaneously in all three cavities allows the formation of a developed mass transfer surface between the coolant and air (approximately 100-10000 cm 2 in 1 cm 3), due to which intensive evaporation of the coolant and saturation of the air with it, accompanied by a large absorption of heat coming from the heat-generating medium. It is advisable that the capillary has a diameter equal to the mean free path of the coolant molecules in the vapor phase at a residual pressure created by the injector-absorber and a temperature equal to the temperature of the liquid coolant, and a length equal to 10-10 5 diameters of the capillary. This ensures intensive mass transfer of the coolant in the direction only from the evaporator to the injector-absorber. It is advisable to make a porous body from two types of pores, the surface of some of which is wetted, while others are not wetted by the coolant. In this case, the porous body is simultaneously permeable to liquid and air and will allow the formation of a more developed mass transfer surface between the coolant and air inside the porous body. This greatly intensifies the evaporation process. The evaporation rate in the evaporator of the porous body structure described above reaches a value close to the evaporation rate in absolute vacuum. It is advisable to bring to the evaporator at least one heat pipe, one end of which is placed in a porous body, and the other in a heat-generating medium, for example, in the ground. This will intensify the heat exchange between the evaporator and the heat-generating medium. The branch pipe for the outlet of the gas-steam mixture of the pressure-separating tank can be connected to a heat exchanger, which is simultaneously in the described installation and a condenser. This will provide heating and, consequently, a decrease in the humidity of the ventilation air sucked into the evaporator from the environment, thereby intensifying the process of evaporation of the coolant in the evaporator. It is advisable to connect the pressure-separating tank to a heat exchanger, which is simultaneously a condenser in the described installation. This will provide heating and, consequently, a decrease in the humidity of the ventilation air sucked into the evaporator from the environment, thereby intensifying the process of the coolant evaporator in the evaporator. The evaporator cavity filled with heat carrier can be connected to the heat exchanger by a heat carrier condensate line. This will avoid losses of the coolant with the vapor-gas mixture separated in the pressure-separating tank and ensure constant replenishment of the coolant in the evaporator. Figure 1 shows a diagram of the proposed heat pump installation; figure 2 the evaporator placed in it a porous body and a heat pipe. The inventive heat pump installation contains a heat exchanger 1 (figure 1) with nozzles 2, 3, respectively, for supplying ventilation air and an air-steam mixture, an evaporator 4 connected to the heat exchanger 1 by a gas-liquid line 5, which is two separate pipes, and with an injector-absorber with a capillary 7 connected to the suction line of the injector-absorber. The capillary must have a diameter equal to the mean free path of the coolant molecules in the vapor phase at the residual pressure created in the injector-absorber 6 and a temperature equal to the temperature of the liquid coolant. The length of the capillary line should be 10-10 5 of the capillary diameter. The injector-absorber 6 is installed on the pressure line of the liquid pump 8 and is connected to the pressure-separating tank 9, filled to 2/3 of its volume with a liquid heat carrier. The pressure-separating tank is connected by line 10 to heat exchanger 1 through branch pipe 3 and line 2, designed to remove the liquid heat carrier, with heating devices 12, which are connected to the suction line of liquid pump 7. Evaporator 4 is made of three independent cavities 13, 14 and 15 ( figure 2). The cavity 13 is connected to the air supply pipe from the heat exchanger. The cavity 15 is filled with a liquid heat carrier and is connected to the heat carrier condensate supply pipe from the heat exchanger 1, which is also a heat carrier vapor condenser. This makes it possible to avoid losses of the coolant with the gas-vapor mixture, which is separated from the liquid coolant in the pressure-separating tank 9. The cavity 14 is connected by means of a capillary line 7 to the suction line of the injector-absorber 6, inside the evaporator 4 there is a porous body 16, made in the form of a thick-walled a cylinder containing two types of pores - the surface of one type of pores is well wetted by the coolant, the surface of the other type of pores is not wetted by the coolant, but is permeable to air. The material for the porous body is selected depending on the coolant, which can be any non-aggressive liquid with a boiling point at a pressure of 1 atm not higher than 150 o C, for example, water, alcohols, ethers, hydrocarbons and their mixtures, consisting of two, three or more components, mutually soluble. The coolant is chosen depending on which room is required to be heated by the installation, on climatic conditions and other factors. The porous body 16 is placed inside the evaporator in such a way that its surfaces are in contact with all three of these cavities. To the evaporator 4 summed up the heat pipe 17, one end of which is placed in the porous body 16, and the other in a heat-generating medium, such as soil. There can be several heat pipes, which will increase the supply of heat from the heat-containing medium to the evaporator and thereby enhance the process of evaporation of the coolant. Heat pump installation works as follows. Air from the atmosphere through the pipe 3 of the air supply due to the rarefaction created by the injector-absorber in the evaporator 4 is sucked into the heat exchanger 1 and through the gas-liquid line 5 through the air pipe enters the chamber 13 of the evaporator 4. Inside the porous body 16, the heat carrier intensively evaporates and saturates it air vapor. In this case, the heat of the heat-generating medium, such as soil, is absorbed, which is supplied to the evaporator through heat pipes 17. The evaporation rate of the heat carrier inside the porous body reaches a value comparable to the evaporation rate in absolute vacuum of 0.3 g/cm 3 s, which corresponds to heat flow 0.75 W/cm 2 porous body. The air saturated with coolant vapor is sucked into the injector-absorber 6 through capillary 7, and the coolant is supplied here by a liquid pump 8 from heating devices 12 under pressure and mixed with the vapor-air mixture, forming an emulsion, which is air bubbles and coolant. In this case, vaporous moisture is absorbed by the liquid with the release of heat equivalent to the heat absorbed in the evaporator. The released heat is used to heat the coolant. The emulsion formed in the injector-absorber 6 enters the pressure-separating tank 9, where it is separated into an air-steam mixture and a liquid heat carrier. From the pressure-separating tank 9, the heated coolant flows by gravity into the heating devices 12 and again to the suction line of the liquid pump 8, thus completing the cycle of the liquid coolant. The air-steam mixture from the pressure-separating tank 9 through line 10 due to a small overpressure, created in the pressure-separating tank 9, enters the heat exchanger 1 through the pipe 3. In the heat exchanger 1, the suction atmospheric air and condensation of the coolant vapors, which separately enter the evaporator 4. Thus, the inventive heat pump unit has high energy performance, without the use of aggressive, environmentally harmful coolants, which makes it safe to operate. Water can be used as a heat carrier. To heat rooms, buildings in harsh climatic conditions, the evaporator can be filled with a low-boiling coolant for more intensive evaporation, and water can be passed through the heating system. For heating, for example, garages, when constant heating is not required even in winter, it is advisable to use alcohols or solutions that have a low freezing point as a heat carrier, which will prevent the system from freezing during the shutdown of the installation. The use of non-aggressive heating fluids eliminates the need to use special materials and alloys in the manufacture of the unit. Some units of the installation, such as a pressure-separating tank, connecting pipelines can be made of plastics, rubber and other non-metallic materials, which will significantly reduce the metal consumption. The installation is technically simple in execution and operation, does not require large energy consumption. The heat generating unit is compact and can be placed in a small area and can be used both for heating large rooms, buildings, and small buildings, as well as garages, and when working in a refrigeration cycle to cool basements in the summer. The possibility of a wide choice of the type of heat carrier allows the use of the unit in any climatic conditions. All this determines the low cost of the installation, the safety of its operation and accessibility for a large number consumers.

Claim

1. A heat pump unit containing a heat exchanger, an evaporator, an injector-absorber, a liquid pump, a pressure-separating tank, characterized in that the unit is equipped with a ventilation air line, at least one capillary and a porous body, and the evaporator is made three-cavity, one cavity of which is connected with a heat exchanger by a ventilation air line, the other is filled with a coolant and the third evacuated cavity is connected to an injector-absorber, while the porous body is placed in all three cavities, and the evaporator and the injector-absorber are interconnected by at least one capillary. 2. Installation according to claim 1, characterized in that the capillary has a diameter equal to the free path of the coolant molecules in the vapor phase at a residual pressure created in the injector-absorber and a temperature equal to the ambient temperature, and the length of the capillary is 10 10 5 its diameter. 3. Installation according to claim 1, characterized in that the porous body is formed by pores of two types, the surface of some of which is wetted, while others are not wetted by the coolant. 4. Installation according to claim 1, characterized in that at least one heat pipe is connected to the evaporator, one end of which is placed in a porous body, and the other in a heat-generating medium. 5. Installation according to claim 1, characterized in that the pressure-separating tank is connected to a heat exchanger. 6. Installation according to claim 1, characterized in that it is provided with a coolant condensate line, through which the evaporator cavity filled with coolant is connected to the heat exchanger.

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 rather 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 steam 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 compressor on water vapor for use in vapor compression HPPs has not yet been carried out.

The main advantages of using water vapor 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 of the working fluid;

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

3. Significantly higher temperatures of the coolant to the consumer (up to 100 °C and above) compared to 70-80 °C 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 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, a decrease in the consumption of 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 shows a schematic diagram of HPI operation when using water vapor (R718) as a working fluid.

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 water vapor, it is proposed to use a commercially available aircraft axial compressor AL-21, which has the following important features when used for steam operation:

♦ 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 construction 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 real operation of HPI at CHPP, the possibility of efficient transfer of waste heat from a steam turbine to the heating network with a HPI conversion factor equal to 5-6 was demonstrated. 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 the heat generated by the HPP can be several times lower (and the KIT is several times higher) than with traditional heat generation at the CHPP.

In the analysis of the effectiveness of the use of heat pumps in centralized systems hot water supply (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 of district heating consumers in 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 steam, 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).

The HPP-2 heat pump units are installed at the CHPP (Fig. 4) and are used during the heating season as a low-temperature source of steam from the outlet of the heating turbines (ventilation passage of the low pressure part (LPP)). 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 MWe (transferred by peak hot water boilers) with the help of HPP-2 additionally installed at the CHPP during the heating period in relation to the Moscow region. 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 ) compared with traditional way its generation at the CHPP of OAO Mosenergo.

It is known that at present the prime cost of fuel cells, calculated according to the so-called “physical method of fuel separation into electricity and heat production”, significantly exceeds 400 rubles/Gcal (the tariff for fuel cells). 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 time, these installations can work according to 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.

* - 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.

A heat pump is a complete heating system capable of heating private house no worse than the traditional, familiar to us heating. 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. - enough complex structure 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. Special pipes weighed down with a load are laid on the bottom of the reservoir or in the bottom soil.

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: