RU2272970C2 - Reversible steam compression system and reversible heat exchanger for fluid coolant - Google Patents

Abstract

FIELD: engineering of steam compression systems and heat exchangers.

SUBSTANCE: reversible steam compression system has compressor, internal heat exchanger, expanding device and external heat exchanger, connected by pipelines in working connection for forming of a single system. Internal and external heat exchangers are mounted in main contour. Compressor and expanding device are mounted in sub-contours, connected to main contour by means of flow switch devices for making it possible to switch system from cooling mode to heating mode. Reversible heat exchanger for liquid coolant, in particular, for carbon dioxide, in steam compression system contains several mutually interconnected sections, made with possible serial passage of air through them, having coolant contour, and is connected to mutually connected first and second sections. Flow of liquid coolant is witched from heating mode to cooling mode by means of flow switching devices, mounted in appropriate sections.

EFFECT: improved efficiency.

2 cl, 46 dwg

Description

The present invention relates to vapor compression systems, such as refrigeration, air conditioning, heat pump systems, and / or combinations thereof, operating under transcritical or subcritical conditions using any refrigerant and, in particular, using carbon dioxide, and more specifically, but not only to a device operating as a reversible cooling system / heat pump system.

An irreversible steam compression system consists of one main circuit comprising a compressor 1, a heat removal device 2, a heat absorption device 3 and an expansion device 6, as shown in FIG. This system can function in either heating or cooling mode. In order to make the system reversible, i.e., so that it can operate both as a heat pump system and as a cooling system, in the prior art, various structural changes in the system are used for this purpose and new units are introduced into the circuit. The prior art and its disadvantages are characterized below.

The most common system includes a compressor, a flow switch valve, an internal heat exchanger, two butterfly valves, two shut-off valves, an external heat exchanger and a low pressure collector. Reversibility is provided by a flow switching valve, two stop valves and two butterfly valves. The disadvantage of this technical solution is the use of two butterfly valves, and the internal heat exchanger will operate in parallel flow in either heating or cooling mode, which is a significant drawback. In addition, this technical solution is not flexible and cannot be effectively applied with systems using an intermediate pressure reservoir.

In publications EP 0604417 B1 and WO 90/07683 a transcritical vapor compression device and methods for controlling the supercritical pressure of its high pressure side are described. The system disclosed in these publications comprises a compressor, a gas cooler (condenser), a counter-current internal heat exchanger, an evaporator, and a collector / accumulator. High pressure is regulated by changing the amount of refrigerant in the collector / accumulator. The throttle device between the high pressure output of the counterflow internal heat exchanger and the evaporator inlet acts as a regulator. This technical solution can be applied either in the heat pump mode or in the cooling mode.

In addition, DE 19806654 describes a reversible heat pump system for land vehicles with an internal combustion engine in which the engine cooling system is used as a heat source. The system described in this publication uses an intermediate pressure collector with a single equilibrium evaporation of the low pressure high-pressure refrigerant in the heat pump mode, but this technical solution is not ideal.

DE 19813674 C1 describes a reversible heat pump system for air conditioning in an automobile in which exhaust gas is used as a heat source. The disadvantage of this system is the possibility of oil decomposition in the heat exchanger (when it is not in operation) to recover the heat of the exhaust gas, since the temperature of the exhaust gas is relatively high.

US Pat. No. 5,890,370 describes a single-stage reversible transcritical vapor compression system that uses a single switching device and a specially designed reversible butterfly valve that can operate in both directions of flow. The main disadvantage of this system is the complex control technique required for a special design butterfly valve. In addition, this system in its current form can only be used for single-stage systems.

US Pat. No. 5,473,906 describes an air conditioner for a car that uses two or more switching devices to transition a system from heating to cooling. Moreover, the system described in this patent has two internal heat exchangers. Compared to the present invention, in one embodiment of an air conditioner in said patent, an internal heat exchanger is disposed between the throttle valve and the second switching device.

The main disadvantage of this device is that the low pressure steam from the outlet of the internal heat exchanger must pass through the second switching device, resulting in an additional pressure drop of the low pressure refrigerant (suction gas) in cooling mode. In the heating mode, the system also increases the pressure drop on the heat removal side of the system, since the exhaust gas must pass through two switching devices before it is cooled. According to yet another embodiment of an air conditioner, in this patent the same internal heat exchanger is located between the first switching device and the compressor. This arrangement also leads to an increased pressure drop on the heat dissipation side in the heating mode. In yet another embodiment, the compressor communicates directly with two four-way valves. This technical solution also leads to an additional pressure drop in the low pressure refrigerant (suction gas) in cooling mode, since the suction gas must pass through two four-way valves before entering the compressor. In heating mode, an increase in pressure drop also occurs in this system. In addition, the placement of the collector after the condenser in the proposed embodiments allows it to be used only for a conventional system with a condenser and an evaporative heat exchanger, since it does not correspond to the transcritical mode of operation, since the pressure collector used does not perform any function in the transcritical mode of operation. Another common drawback of the system is that it cannot be used for applications such as a simple single system, two-stage compression, combined water heating and cooling, as provided by the present invention, since the system in this patent is intended solely for air conditioning in a car .

Regarding the second aspect of the present invention, US-Re030433 describes the operation of a heat exchanger as a condenser and an evaporator, and in this application discloses its operation as an evaporator and a gas cooler. In the latter case, the refrigerant is a single-phase fluid, and there is no question of condenser drainage. The function of the gas cooler is often to heat the air flow in a certain temperature range, and this cannot be done if the heat exchanger sections operate in parallel on the air side. Therefore, in gas coolers, the design of the circuit will be different from the heat exchanger, which should serve as a condenser. In this application, the air always passes sequentially through the sections of the heat exchanger, while according to the invention in the publication US-Re030433 air passes through all the "heat transfer zones" in parallel.

US-Re030745 describes a reversible heat exchanger, which is very similar to that described above (US-Re030433), including the fact that operation is limited to evaporative and condenser modes. In this case, air also passes in parallel through all sections. Another important difference is that in the heat exchanger according to the patent all sections are connected in parallel on the refrigerant side during operation as an evaporator. In this application, the refrigerant passes sequentially through the heat exchanger also in the evaporative mode.

The present invention is the creation of a reversible heat exchanger that serves as a heater in one mode, cooling the refrigerant with supercritical pressure, and an evaporator in another mode; in both cases, refrigerant and air pass sequentially through the sections. The only difference is that during operation in gas cooling mode the refrigerant passes sequentially through all sections in countercurrent with respect to air, and during operation in evaporation mode two and two sections are connected in parallel.

The technical result is achieved by means of a reversible steam compression system comprising a compressor, an internal heat exchanger, an expansion device and an external heat exchanger connected by pipelines in a working relationship to form a single system, while the internal and external heat exchangers are installed in the main circuit, and the compressor and expansion device are installed in the subcontours accordingly, while the sub-circuits communicate with the main circuit by means of flow switching devices, respectively, for Sintered switching system from cooling mode to heating mode.

The flow switching devices are made in one node, performing the same function.

The system comprises an additional bypass line comprising a dewatering heat exchanger, an expansion device and a valve installed between the switching device and the expansion device on the inlet side, and the switching device and the suction side of the compressor on the exhaust side.

The system also includes a heat exchanger connected in parallel in the heating mode and in series in the cooling mode using flow changing devices.

Preferably, the expansion device in the sub-circuit further comprises three mutually connected parallel pipes, the external parallel pipes of which are connected to the main circuit by flow switching devices, which are flow-deflecting expansion devices.

In one embodiment, the first sub-circuit has an additional heat exchanger downstream of the compressor, and the second sub-circuit has an additional heat exchanger upstream of the expansion device.

In this case, the sub-circuits to the compressor in the first sub-circuit, respectively, to the expansion device in the second sub-circuit have an additional internal heat exchanger.

In another embodiment, the second sub-circuit has a collector (7) after an expansion device, but before an additional expansion device.

The system is configured to compress in two stages, the flash vapor being pumped out of the collector through a bypass line by a second compressor stage.

The system is configured to provide additional cooling performance at intermediate pressure and temperature using a heat exchanger. In this case, the heat exchanger is a gravity fed evaporator or pump connected to the collector and is located in the bypass line using another expansion device, the bypass line inlet is connected between the switching device and the expansion device, and the bypass outlet is connected to the collector.

Preferably, the compression in the system is performed using a two-stage compressor, which is a variable stroke compressor. In this case, compression is compression of the double effect type and is carried out by means of two separate compressors of the first and second stages.

The exhaust gas from the compressor of the first stage is fed into the collector through the bypass line before it is pumped out of the collector through the bypass line by the compressor of the second stage.

The system additionally contains an internal heat exchanger installed in the first sub-circuit before the compressor, and is designed for heat exchange between the circuit and the second sub-circuit through a connecting bypass line installed before the expansion device.

Preferably, an additional collector is installed in the first sub-loop in front of the additional heat exchanger.

In the bypass line after the internal heat exchanger, an additional intermediate cooling heat exchanger is installed, while part of the refrigerant from the bypass line is taken and passed through the low pressure side of the intermediate cooling heat exchanger and then to the compressor through the bypass line, and the main part of the refrigerant is returned to the second sub-circuit.

Preferably, the collector is located in the middle pipe after the expansion device, which is also located in the middle pipe, and the flow-deflecting expansion devices are made in the form of two flow-deflecting devices. An optional expansion device can be installed after the collector.

The system preferably operates under transcritical conditions using carbon dioxide as a reversible cooling system and heat pump system. In this case, the thawing of the frozen heat exchanger (evaporator) is performed through the process of switching from the heat pump mode to the cooling mode.

The technical result is also achieved by means of a reversible heat exchanger for fluid refrigerant, in particular carbon dioxide, in a steam compression system containing several interconnected sections made with the possibility of successive passage of air through them, having a refrigerant circuit connected to interconnected by connections of the first and second sections, while the flow of fluid refrigerant is switched from heating to cooling using flow switching devices installed respective sections.

Preferably, the flow switching devices are stop valves, and the connections are nozzles.

The invention is characterized in that the flow of fluid refrigerant in the heat exchanger can be switched from the heating mode to the cooling mode by means of flow switching devices installed between the heat exchanger sections.

An additional embodiment of the invention relates to a reversible defrosting steam compression system, which is a well-known defrosting system for a heat exchanger, for example, in a heat pump system using air as a heat source. This embodiment is characterized in that the switching is performed by two switching devices.

The scope of this invention can be, but not limited to, stationary and mobile air conditioning units / heat pump units and refrigerators / freezers. In particular, this device can be used for air conditioning systems and heat pump systems and for air conditioning systems / heat pump systems in vehicles with an internal combustion engine and also in electric vehicles or in mixed land vehicles.

The invention is further described in more detail with specific examples and with reference to the drawings, in which:

Figure 1 is a schematic view of an irreversible vapor compression system.

Figure 2 is a schematic view of the most common type of system layout used for a reversible heat pump system.

Figure 3 is a schematic view of a first embodiment of a system in a heating mode.

4 is a schematic view of a first embodiment of a system in cooling mode.

5 is a schematic view of a second embodiment of a system in heating mode.

6 is a schematic view of a second embodiment of a system in cooling mode.

7 is a schematic view of a third embodiment of a system in heating mode.

Fig. 8 is a schematic view of a third embodiment of a system in cooling mode.

Fig.9 is a schematic view of a fourth embodiment of a system in a heat pump operation mode.

10 is a schematic view of a fourth embodiment of a system in a cooling mode.

11 is a schematic view of a fifth embodiment of a system in a heat pump operation mode.

12 is a schematic view of a fifth embodiment of a system in cooling mode.

13 is a schematic view of a sixth embodiment of a system in a heat pump operation mode.

Fig. 14 is a schematic view of a sixth embodiment of a system in a cooling mode.

15 is a schematic view of a seventh embodiment of a system in a heat pump operation mode.

Fig. 16 is a schematic view of a seventh embodiment of a system in a cooling mode.

17 is a schematic view of an eighth embodiment of a system in a heat pump operation mode.

Fig. 18 is a schematic view of an eighth embodiment of a system in cooling mode.

Fig. 19 is a schematic view of a ninth embodiment of a system in a heat pump operation mode.

Fig. 20 is a schematic view of a ninth embodiment of a system in a cooling mode.

Fig is a schematic view of a tenth embodiment of a system in a heat pump operation mode.

Fig is a schematic view of a tenth embodiment of a system in cooling mode.

23 is a schematic view of an eleventh embodiment of a system in a heat pump operation mode.

24 is a schematic view of an eleventh embodiment of a system in cooling mode.

25 is a schematic view of a twelfth embodiment of a system in a heat pump operation mode.

26 is a schematic view of a twelfth embodiment of a system in a cooling mode.

Fig. 27 is a schematic view of a thirteenth embodiment of a system in a heat pump operation mode.

Fig. 28 is a schematic view of a thirteenth embodiment of a system in a cooling mode.

Fig. 29 is a schematic view of a fourteenth embodiment of a system in a heating mode.

Fig. 30 is a schematic view of a fourteenth embodiment of a system in a cooling mode.

Fig is a schematic view of a fifteenth embodiment of the system in heating mode.

32 is a schematic view of a fifteenth embodiment of a system in cooling mode.

Fig. 33 is a schematic view of a sixteenth embodiment of a system in a heating mode.

Fig. 34 is a schematic view of a sixteenth embodiment of a system in a cooling mode.

Fig. 35 is a schematic view of a seventeenth embodiment of a system in a heating mode.

Fig. 36 is a schematic view of a seventeenth embodiment of a system in a cooling mode.

Fig. 37 is a schematic view of an eighteenth embodiment of a system in a heating mode.

Fig. 38 is a schematic view of an eighteenth embodiment of a system in a cooling mode.

Figures 39-46 are schematic views of a second feature of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

Figure 1 shows a schematic view of an irreversible steam compression system comprising a compressor 1, heat exchangers 2, 3 and an expansion device 6.

Figure 2 shows a schematic view of the most common steam compression system for a reversible heat pump system. The drawing shows the elements included in this known system. The mode is switched using two different expansion valves with shut-off valves on the bypass and a 4-way valve.

A first embodiment of the present invention for a single-stage reversible steam compression cycle is shown schematically in FIG. 3 in heating mode and in FIG. 4 in cooling mode. In accordance with the present invention, the system comprises a compressor 1, an internal heat exchanger 2, an expansion device 6 (for example, a butterfly valve) and an external heat exchanger 3. It should be noted that the entire system contains connecting pipelines to create a closed main circulation circuit in which the refrigerant circulates. Distinctive features of the first embodiment of the invention are the use of two subcontours, the first circuit A and the second circuit B, respectively connected to the main circulation circuit through the first 4 and second 5 flow switching devices, which can be performed, for example, in the form of a 4-way valve. Compressor 1 and expansion device 6 are installed in the first sub-circuit A and the second sub-circuit B, respectively, while the internal heat exchanger 2 and the external heat exchanger 3 are installed in the main circuit, which communicates with the sub-circuits through the first and second flow switching devices. This main embodiment (which is the basis of other embodiments in this application) operates with a minimum pressure drop in both heating mode and cooling mode, without reducing the efficiency of the system. In addition, it includes new elements providing new embodiments that expand its applicability, including a wide range of applications of a reversible cooling system and a heat pump system.

This embodiment and additional embodiments, without a low pressure collector, have the advantage that the need for additional control of the oil backflow is eliminated. Switching from the cooling mode to the heating mode is carried out simply and efficiently with the help of two switching devices 4 and 5, which connect the main circuit to circuit A and circuit B, respectively.

The principle of operation is as follows.

Heat pump operation

In Fig. 3, the flow switching devices 4 and 5 are in the heating mode position, as a result of which the external heat exchanger 3 acts as an evaporator and the internal heat exchanger 2 as a gas cooler (condenser). The circulating refrigerant evaporates in the external heat exchanger 3 by absorbing heat from the heat source. The steam passes through the flow switching device 4 and then is pumped out by the compressor 1. The pressure and temperature of the steam are increased by the compressor, after which the steam enters the internal heat exchanger 2, passing through the flow switching device 4. Depending on the pressure, the refrigerant vapor either condenses (at subcritical pressure) or cools (at supercritical pressure), transferring heat to the heat absorber (internal air in the case of an air system). The high pressure refrigerant then passes through the flow switching device 5, and then its pressure is reduced by the expansion device 6 to the evaporation pressure. The refrigerant passes through the flow switching device 5, then enters the external heat exchanger 3, completing the cycle.

Cooling operation

In Fig. 4, the flow switching devices 4 and 5 are in the cooling mode position, as a result of which the internal heat exchanger 2 acts as an evaporator and the external heat exchanger 3 as a gas cooler (condenser). The circulating refrigerant evaporates in the internal heat exchanger 2 by absorbing heat from the internal cooling medium. The steam passes through the flow switching device 4 and then is pumped out by the compressor 1. The pressure and temperature of the steam are increased by the compressor 1, after which the steam enters the external heat exchanger 3, passing through the flow switching device 4. Depending on the pressure, the refrigerant vapor either condenses (at subcritical pressure) or cools (at supercritical pressure), transferring heat to the heat sink. The high pressure refrigerant then passes through the flow switching device 5, and then its pressure is reduced by the expansion device 6 to the evaporation pressure. The low pressure refrigerant passes through the flow switching device 5, then enters the internal heat exchanger 2, completing the cycle.

The main advantage of this embodiment is that it requires a minimum number of elements, as well as the simplicity of the principle of operation of the system and its management. On the other hand, due to the lack of a collector / accumulator, the energy efficiency and general characteristics of the system are affected by changes in the cooling / heating load and any possible refrigerant leaks.

Second Embodiment

5 and 6 show schematic views of a second embodiment of the system during operation in heating and cooling modes, respectively. Compared with the first embodiment, in this embodiment, there is an additional bypass line C which comprises a dewatering heat exchanger 25, an expansion device 23 and a valve 24. The heat exchanger 25 performs the function of dehydration during operation in heating mode and operates as a conventional evaporator in cooling mode. In the heating mode, a certain amount of high pressure refrigerant after the switching device 5 is withdrawn through the expansion device 23, where the pressure of the refrigerant is reduced to the evaporation pressure in the heat exchanger. The refrigerant then evaporates by absorbing heat in the heat exchanger 25, and then it passes through the valve 24. Thus, the internal air passes through the dehydrating heat exchanger 25 and then is heated again by the internal heat exchanger 2, supplying drier air to the inner space to prevent fogging, for example, windshield in an automotive air conditioning system. In cooling mode, the heat exchanger 25 provides additional heat transfer area for cooling the internal air. Switching of this system is performed in the same way as in the first embodiment, i.e. by changing the position of the two devices 4 and 5 switching the flow from heating mode to cooling mode, and vice versa.

Third Embodiment

Figures 7 and 8 show schematic views of a third embodiment of a system during operation in heating and cooling modes, respectively. Compared to the second embodiment, the bypass line C with respect to the main circuit is configured such that the dewatering heat exchanger 25 and the internal heat exchanger 2 are connected in series during cooling operation by means of additional flow switching devices 26 and 26 '(e.g. a check valve), opposite to the second embodiment, in which the heat exchangers are connected in parallel regardless of the mode of operation. System switching is performed as in the first embodiment, i.e. by changing the position of the two devices 4 and 5 switching the flow from heating mode to cooling mode, and vice versa.

Fourth Embodiment

This embodiment is an improvement on the first embodiment and is shown schematically in FIG. 9 in heating mode and in FIG. 10 in cooling mode. According to the present invention, the device comprises a compressor 1, a sub-circuit with a flow switching device 4, an internal heat exchanger 2 and an external heat exchanger 3. The difference from the previous embodiment is that the expansion device (6) in the sub-circuit (B) further comprises three interconnected parallel pipes (B1, B2, B3), the external parallel pipes (B1, B3) of which are connected to the main circuit by means of flow switching devices, which are expansion deflecting expansion devices (17 ', 16').

Switching from operation in cooling mode to operation in heating mode is carried out simply and efficiently by means of a flow switching device 4 and two flow-deflecting expansion devices 16 'and 17'.

The principle of action is as follows.

Heat pump operation

In Fig. 9, the flow switching device 4 and the flow-deflecting expansion devices 16 'and 17' are in the heating mode position, as a result of which the heat exchanger 3 acts as an evaporator and the internal heat exchanger 2 as a gas cooler (condenser). The circulating refrigerant evaporates in the heat exchanger 3 by absorbing heat from the heat source. The steam passes through the flow switching device 4 and then is pumped out by the compressor 1. The pressure and temperature of the steam are increased by the compressor 1, after which the steam enters the internal heat exchanger 2, passing through the flow switching device 4. Depending on the pressure, the refrigerant vapor either condenses (under subcritical pressure) or cools (under supercritical pressure), giving off heat to the heat absorber (internal air in the case of an air system). The high pressure refrigerant then passes through the first flow deflecting device 16 ', then its pressure is reduced by the second flow deflecting device 17' to the evaporation pressure in the internal heat exchanger 3, completing the cycle.

Cooling operation

10, the flow switching device 4 and the flow-deflecting expansion devices 16 'and 17' are in the cooling mode position, as a result of which the internal heat exchanger 2 acts as an evaporator and the external heat exchanger 3 as a gas cooler (condenser). The circulating refrigerant evaporates in the internal heat exchanger 2 by absorbing heat from the heat source. The refrigerant passes through the flow switching device 4 and then is pumped out by the compressor 1. The pressure and temperature of the steam are increased by the compressor 1, after which it passes to the external heat exchanger 3, passing through the flow switching device 4. Depending on the pressure, the refrigerant vapor either condenses (under subcritical pressure) or cools (under supercritical pressure), transferring heat to the heat sink. The high pressure refrigerant then passes through the second flow deflecting expansion device 17 ', then its pressure is reduced by the first flow deflecting expansion device 16' to the evaporation pressure in the external heat exchanger 2, completing the cycle.

Fifth Embodiment

11 and 12 show a schematic view of a fifth embodiment of the system during operation in heating mode and cooling mode, respectively. This embodiment is a reversible steam compression system with a heating function of tap water. Tap water is heated first by a heat exchanger 24 in sub-circuit B and then it is heated to the desired temperature by a second water heat exchanger 23 in sub-circuit A. The heat load of the water heating heat exchanger 23 can be controlled by changing the water flow in the heat exchanger 23, or by using bypass on the refrigerant side of the heat exchanger .

Sixth Embodiment

13 and 14 are schematic views of a sixth embodiment, which is an improvement of the first embodiment of the invention. Compared to the first embodiment, this embodiment has an additional countercurrent internal heat exchanger 9 located in the sub-circuit A and exchanging heat with the refrigerant in the sub-circuit B by connecting the bypass line 12. Tests carried out on the well-known steam compression unit operating in cooling mode showed that the use of an additional internal heat exchanger can reduce energy consumption and increase cooling efficiency at an elevated temperature of the heat absorber (high cooling load). The switching process is performed according to the first embodiment.

Seventh Embodiment

A seventh embodiment of the invention is shown schematically in FIG. 15 in heating mode and in FIG. 16 in cooling mode. The main difference between this embodiment and the first embodiment is the presence of an intermediate pressure collector 7 in the sub-circuit B, which results in a two-stage expansion of the high pressure refrigerant. According to this embodiment, the reversible vapor compression device comprises a compressor 1, a flow switching device 4, another flow switching device 5, an expansion device 6, and an external heat exchanger. Switching is carried out in the same way as in the previous embodiment, i.e. by changing the position of the two devices 4 and 5 switching the flow from heating mode to cooling mode, and vice versa. This embodiment is an improvement on the first embodiment by introducing an intermediate pressure collector / accumulator 7, which allows for active control of high pressure and cooling / heating performance to maximize productivity. The system becomes more stable in operation and is not affected by possible leaks, since a certain level of liquid refrigerant is provided in the collector / accumulator 7 of the intermediate pressure.

Eighth Embodiment

The eighth embodiment is an improvement on the fourth embodiment, and is shown schematically in FIG. 17 in heating mode and in FIG. 18 in cooling mode. The main difference between this embodiment and the fourth embodiment is the use of an intermediate pressure collector 7 located in the middle nozzle B2 of the second sub-circuit B, which results in a two-stage expansion of the high pressure refrigerant by means of flow-extending expansion devices 16 'and 17', respectively. This system becomes more stable and is not affected by possible leaks, since there is a certain level of liquid refrigerant in the intermediate pressure collector / accumulator 7.

Ninth Embodiment

A ninth embodiment of the invention is shown schematically in FIG. 19 in heating mode and in FIG. 20 in cooling mode. This embodiment is similar to the eighth embodiment, except for the fact that the flow diversion and expansion function is performed by two separate diverters 16 and 17 and two expansion devices 6 and 8 in the middle pipe B2 above and respectively under the collector 7. According to this embodiment, the system contains compressor 1, flow switching device 4, internal heat exchanger 2, flow deflecting device 16, expansion device 6, intermediate pressure collector 7, expansion device 8, a flow deflecting device 17, and an external heat exchanger. In this embodiment, the system is switched using one switching device 4 and two flow-deflecting devices 16 and 17, which are installed either in cooling mode or in heating mode.

Tenth Embodiment

A tenth embodiment is shown in FIG. 21 in a heating mode, and in FIG. 22 in a cooling mode. Compared to the seventh embodiment, this embodiment comprises a countercurrent internal heat exchanger 9 in the sub-circuit A, which exchanges heat with the sub-circuit B through a bypass line 12, which is connected to the sub-circuit B to the expansion device 6. Tests carried out on a known steam compression unit operating in cooling mode, showed that the use of an internal heat exchanger can reduce energy consumption and increase cooling performance at elevated temperatures heat transfer agent (high cooling load). The principle of operation is the same as in the fifth embodiment, except for the fact that the warm high pressure refrigerant after the flow switching device 5 exchanges heat through the internal heat exchanger 9 with cold low pressure refrigerant after the switching device 4 until expansion in the expansion device 6 in the collector / accumulator 7 of intermediate pressure. Switching is performed according to the first embodiment.

Eleventh Embodiment

An eleventh embodiment of the invention is shown in FIG. 23 in a heating mode, and in FIG. 24 in a cooling mode. The main difference between this embodiment and the tenth embodiment is the presence of a counterflow internal heat exchanger 9 on the high pressure side. According to the eighth embodiment, the high pressure side of the internal heat exchanger 9 is located in the sub-circuit B between the switching device 5 and the expansion device 8, but in this embodiment, the high pressure side of the internal heat exchanger 9 is located between the switching device 5 and the external heat exchanger 3. Therefore, according to this embodiment, the internal heat exchanger will not be “active” in either heating mode or cooling mode, since there is a very limited temperature for heat transfer -temperature driving force.

Twelfth Embodiment This embodiment is shown in FIG. 25 in a heating mode and in FIG. 26 in a cooling mode. This embodiment is a two-stage reversible steam compression device in which the compression is carried out in two stages: steam is pumped out under intermediate pressure through a pipe 20 from the collector / accumulator 7 into sub-circuit B, as a result of which the vapor compression efficiency is increased. In addition, this embodiment provides the possibility of improving the regulation of the intermediate pressure generated in this case in the intermediate pressure collector / accumulator 7. Compressor 1 can be implemented as a single double expansion unit with an intermediate suction inlet or as two separate compressors of any type of the first stage and second stage. The compressor may also be a “double-effect compression” type compressor (GTVoorhees 1905, British Patent No. 4448), in which the piston compressor cylinder has an inlet that is not closed at or near the center of the piston's dead center, introducing steam under intermediate pressure and thereby increasing the cooling or heating performance of the system. When using a "double effect" compressor with a variable stroke (displacement), this input can only be opened if the demand for heating or cooling increases, in order to increase system performance.

The principle of operation in this embodiment is the same as in the first embodiment, except for the fact that the compression is performed in two stages, and the resulting flash vapor in the intermediate pressure collector / accumulator 7 after the expansion device 6 is pumped out by the second stage compressor along the line 12. If a two-stage compressor or two separate compressors are used, the cold flash vapor is mixed with the outgoing gas from the first compression stage, as a result of which the gas temperature is lower in ag ood sort beginning of the second compression stage. Therefore, the entire compression work according to this embodiment will be less than in the embodiments of single-stage reversible transcritical vapor compression, which, as a rule, provides an increase in energy efficiency.

Thirteenth Embodiment

A thirteenth embodiment is shown schematically in FIGS. 27 and 28 in a heating mode and a cooling mode, respectively. Compared to the twelfth embodiment, this embodiment provides an additional heat exchanger 10, which provides additional cooling performance at intermediate pressure and temperature. The heat exchanger 10 may be a heat exchanger / evaporator with a gravity feed or a pump. The heat exchanger 10 can also be made integral with the intermediate pressure collector 7. This embodiment is an improvement on the twelfth embodiment, since it can be performed similarly to systems in which cooling must be carried out at two temperature levels. For example, an air conditioning system for mixed ground vehicles or electric vehicles should provide cooling for the engine and for the cab. The present invention can provide cooling of the internal space at a pressure and temperature of evaporation, and cooling of the engine will be ensured by intermediate pressure and temperature. The heat absorbed by the heat exchanger can also be used as an additional heat source in the heating mode. System switching is performed in the same way as in the first embodiment, i.e. by changing the position of the two devices 4 and 5 switching the flow from heating mode to cooling mode, and vice versa.

Fourteenth Embodiment

A fourteenth embodiment is shown schematically in FIGS. 29 and 30 in a heating and cooling mode, respectively. This embodiment is the same as the thirteenth embodiment, with the exception that the heat exchanger 10 is located in sub-circuit D. This sub-circuit also has an additional expansion device 20. In both heating and cooling modes, part of the high pressure refrigerant is vented using expansion device 20, in which the refrigerant pressure is reduced to an intermediate pressure level. The refrigerant then evaporates by absorbing heat in the heat exchanger, and then it passes into the intermediate pressure collector 7. System switching is carried out in the same way as in the first embodiment, i.e. by changing the position of the two switching devices 4 and 5 from the heating mode to the cooling mode, and vice versa.

Fifteenth Embodiment

A fifteenth embodiment of the invention is shown schematically in FIGS. 31 and 32 in a heating mode and a cooling mode, respectively. This embodiment is characterized by two-stage compression with “intercooler” achieved by discharging hot gas through the nozzle 12 ′ from the first stage compressor 1 to the intermediate pressure collector / accumulator 7. In this case, the temperature of the suction gas of the compressor 1 '' of the second stage will be saturated at a temperature corresponding to the saturation pressure in the collector / accumulator 7 of the intermediate pressure. Therefore, in contrast to single-stage compression embodiments, the total amount of compression work will be less and the efficiency of the system will be higher. If necessary, it is also possible to control the superheat of the suction gas for the second compression stage by directing a certain amount of hot exhaust gas from the first stage directly to the suction line of the second compression stage, i.e. due to bypassing the collector / accumulator 7 of the intermediate pressure. System switching is carried out in the same way as in the first embodiment, i.e. by changing the position of the two devices 4 and 5 switching the flow from heating mode to cooling mode, and vice versa.

Sixteenth Embodiment

33 and 34 show a sixteenth embodiment of a steam compression system operating in a cooling mode and a heating mode, respectively. This embodiment is a two-stage reversible steam compression system similar to the fifteenth embodiment, but also has a countercurrent internal heat exchanger 9 in the sub-circuit A, which provides heat exchange with the sub-circuit B through the bypass 18. The advantage of using the counter-current internal heat exchanger 9 is to reduce the temperature of the high refrigerant pressure before it passes through the expansion device 6, resulting in an increase in productive minute cooling and higher energy efficiency. The principle of operation of this embodiment is the same as in the fifteenth embodiment, except for the fact that the high pressure refrigerant after the flow switching device 5 passes through the internal heat exchanger 9 until it passes through the expansion device 6. The system is switched in the same way as in the first embodiment, i.e. by changing the position of the two devices 4 and 5 switching the flow from heating mode to cooling mode, and vice versa.

Seventeenth Embodiment

This embodiment is shown schematically in FIGS. 35 and 36 in heating mode and cooling mode, respectively. This embodiment is similar to the sixth embodiment, except that it has an additional low-pressure collector 15 in the sub-circuit B. The system is switched in the same way as in the first embodiment, i.e. by changing the position of the two devices 4 and 5 switching the flow from heating mode to cooling mode, and vice versa.

Eighteenth Embodiment

An eighteenth embodiment is shown schematically in FIG. 37 in a heating mode, and in FIG. 38 in a cooling mode. In accordance with this embodiment, the system provides two-stage reversible vapor compression, wherein the vapor compression is performed in two stages with “intermediate cooling”, thereby increasing the vapor compression efficiency and overall system characteristics. This embodiment comprises a main circuit, an internal heat exchanger 2, a sub-circuit A connected to the main circuit via the flow switching device 4, and a sub-circuit B connected to the main circuit via the second flow switching device 5. Sub-circuit A contains a compressor 1, a low-pressure collector 15, and a counterflow internal heat exchanger 9. Sub-circuit B contains an expansion device 6. Heat is exchanged between the two sub-circuits by means of the internal heat exchanger 9 when refrigerant flows from sub-circuit B through line 12. An intercooler 14 is also installed. A portion of the refrigerant is passed through this heat exchanger and returned to sub-circuit B, while another portion of the refrigerant is passed through a different sub-circuit 19 through the expander 13 to another flow line of the intercooler 14 and to the second stage of the compressor 1. Compared to the thirteenth embodiment, the introduction of the intercooler 14 cooling as a result provides increased cooling performance and a reduction in the amount of compression work.

Compressor 1 can be a multiple expansion compressor (single) with an intermediate suction inlet or with two separate compressors of any type of the first and second stages. System switching is carried out in the same way as in the first embodiment, i.e. by changing the position of the two devices 4 and 5 switching the flow from heating mode to cooling mode, and vice versa.

The steam compression system can operate either in air conditioning mode for cooling or in heating mode for heating. The operating mode is changed by changing the direction of flow of the refrigerant in the circuit.

During air conditioning, the internal heat exchanger absorbs heat due to the evaporation of the refrigerant, and the heat is removed through an external heat exchanger. During heating, the external heat exchanger acts as an evaporator, and heat is removed through an external heat exchanger.

Since the internal and external heat exchangers must perform a dual purpose, this design is a compromise that is not optimal for both modes. If carbon dioxide is used as the refrigerant, the heat exchangers must act both as an evaporator and as a gas cooler, with very different requirements for an optimal design. During gas cooling, a counterflow heat exchanger and a relatively high mass flow rate of the refrigerant are desirable. It should be noted that a reduced mass flow rate is desirable during the evaporation process, and cross-circulation of refrigerant is acceptable.

Using appropriate means (e.g. stop valves), the circuit in the heat exchanger can be changed with a corresponding change in operating mode. Valves can provide a different circuit for the heat exchanger depending on the direction of flow of the refrigerant. On Fig-46 shows different heat exchangers with two, three, four and six sections in heating mode and cooling mode, respectively. When operating in heating mode, according to Figs. 39, 41, 43 and 45, the refrigerant flows sequentially through each of the four sections in a cross flow. On the other hand, by changing the flow direction, the refrigerant circulates in parallel through one and two, or two and two plates, entering the air inlet side according to Figs. 40, 42, 44 and 46. The change in flow direction is preferably effected by stop valves, but can be other types of valves are also used.

Claims (31)

1. A reversible steam compression system comprising a compressor (1), an internal heat exchanger (2), an expansion device (6) and an external heat exchanger (3) connected by pipelines in working relationship to form a single system, characterized in that the internal and external heat exchangers are installed in the main circuit, and the compressor and expansion device are installed in the sub-circuits A and B, respectively, while the sub-circuits A and B are in communication with the main circuit through devices (4) and (5) for switching the flow, respectively, to ensure Switching the system from cooling to heating mode. 2. The system according to claim 1, characterized in that the devices (4) and (5) for switching the flow are made in one node, performing the same function. 3. The system according to claim 1, characterized in that it contains an additional bypass line containing a dewatering heat exchanger (25), an expansion device (23) and a valve (24) installed between the switching device (5) and the expansion device (6) on the side the inlet and the switching device (4) and the suction side of the compressor on the exhaust side. 4. The system according to claim 3, characterized in that it comprises a heat exchanger (25) connected in parallel in the heating mode and sequentially in the cooling mode by means of flow change devices (26 and 26 '). 5. The system according to claim 1, characterized in that the expansion device (6) in the sub-circuit (B) additionally contains three mutually connected parallel pipes (B1, B2, B3), the external parallel pipes (B1, B3) of which are connected to the main circuit by means of flow switching devices, which are flow-deflecting expansion devices (17 ', 16'). 6. The system according to one of claims 1 to 5, characterized in that the first sub-circuit (A) has an additional heat exchanger (23) after the compressor, and the sub-circuit (B) has an additional heat exchanger (24) in front of the expansion device (6). 7. The system according to one of claims 1 to 5, characterized in that the sub-circuits to the compressor in the sub-circuit (A), respectively, to the expansion device (6) in the sub-circuit (B) have an additional internal heat exchanger (9). 8. The system according to one of claims 1 to 5, characterized in that the sub-circuit (B) has a collector (7) after the expansion device (6), but before the additional expansion device (8). 9. The system according to one of claims 1 to 8, characterized in that it is configured to compress in two stages, and the flash vapor from the collection (7) is pumped through the bypass line (12 ') by the second stage of the compressor (1). 10. The system according to claim 9, characterized in that it is configured to provide additional cooling performance at intermediate pressure and temperature using a heat exchanger 10. 11. The system according to claim 10, characterized in that the heat exchanger (10) is an evaporator with a gravity feed or a pump connected to the collector (7). 12. The system of claim 10, wherein the heat exchanger (10) is located in the bypass line D, using another expansion device (20), and the inlet of the bypass line is connected between the switching device 5 and the expansion device (6), and the release of the bypass lines connected to collector 7. 13. The system according to one of claims 9 to 12, characterized in that the compression is performed using a two-stage compressor. 14. The system according to one of paragraphs.9-12, characterized in that the compression is a compression type of double effect. 15. The system according to one of claims 9 to 12, characterized in that the compressor (1) is a variable speed compressor. 16. The system according to one of claims 9 to 12, characterized in that the compression is carried out by means of two separate compressors (1 ', 1' ') of the first and second stages. 17. The system according to claim 9 or 16, characterized in that the exhaust gas from the compressor (1 ') of the first stage is supplied to the collector (7) through the bypass line (12') before it is pumped out of the collector through the bypass line (12) by the compressor ( 1``) second stage. 18. The system according to one of claims 9-17, characterized in that the additional internal heat exchanger (9) is installed in the sub-circuit (A) to the compressor (1) and is designed for heat exchange between the circuit and the sub-circuit (B) through a connecting bypass line (18 ) installed before the expansion device (6). 19. The system according to claim 18, characterized in that the additional collector (15) is located in the sub-circuit (A) in front of the additional heat exchanger (9). 20. The system according to claim 19, characterized in that the compression is carried out in two stages or as a compression of the double effect. 21. The system according to claim 20, characterized in that the additional intermediate cooling exchanger (14) is installed in the bypass line (12) after the internal heat exchanger (9), while part of the refrigerant from the bypass line (12) is taken out and passed through the low pressure side the heat exchanger (14) for intermediate cooling and then to the compressor (1) through the bypass line (19), and the main part of the refrigerant is returned to the sub-circuit (B). 22. The system according to claim 5, characterized in that the collector (7) is installed in the middle pipe (B2). 23. The system according to claim 5, characterized in that the expansion device (6) is located in the middle pipe (B2), and the flow-deflecting expansion devices (16 ', 17') are made in the form of two flow-deflecting devices (16, 17). 24. The system according to claim 5 or 23, characterized in that the collector (7) is located in the middle pipe (B2) after the expansion device (6). 25. The system according to paragraph 24, wherein the additional expansion device (8) is installed after the collector (7). 26. The system according to one of claims 1 to 25, characterized in that the cycle is transcritical. 27. The system according to one of claims 1 to 26, characterized in that the refrigerant is carbon dioxide. 28. The system according to one of the preceding paragraphs, characterized in that the thawing of the frozen heat exchanger (evaporator) is performed through the process of switching from the heat pump mode to the cooling mode. 29. A reversible heat exchanger for fluid refrigerant, in particular carbon dioxide, in a steam compression system containing several interconnected sections (22) configured to sequentially pass air through them, having a refrigerant circuit connected to interconnected via connections (21) the first and second sections, characterized in that the flow of fluid refrigerant is switched from heating mode to cooling mode using flow switching devices (20) installed in the respective sections (22). 30. The heat exchanger according to clause 29, wherein the flow switching devices are stop valves (20). 31. A heat exchanger according to claim 29 or 30, characterized in that the compounds (21) are nozzles.

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