Heat pump assembly and method of operating the heat pump assembly

Abstract

Heat pump assembly and method of operating the heat pump assembly The present invention relates to a heat pump assembly (1) having a single fluid circuit for a working fluid, the heat pump assembly (1) comprising: one evaporator unit (2); one compressor assembly (5) located downstream of the evaporator unit (2); one condenser unit (8) located downstream of the compressor assembly (5); one return pipe (11) connecting the outlet of the condenser unit (8) to the inlet of the evaporator unit (2); and one expansion assembly (12) provided in the return pipe (11) for expanding the working fluid, having one or more expansion stages (13a, 13b).

Description

Technical Field

[0001] The present invention relates to a heat pump assembly having a fluid circuit for a working fluid, the fluid circuit comprising one evaporator unit for transferring thermal energy from a heat source, in particular a heat source fluid, to the working fluid, one compressor assembly arranged downstream of the evaporator unit for compressing the working fluid, one condenser unit arranged downstream of the compressor assembly for releasing thermal energy, in particular to a sink fluid, preferably for evaporating the sink fluid, one return pipe connecting the outlet of the condenser unit to the inlet of the evaporator unit, and one expansion assembly provided in the return pipe for expanding the working fluid, the expansion assembly having one or more expansion stages.

[0002] Furthermore, the present invention relates to a method of operating a heat pump assembly in which the working fluid is guided through a fluid circuit, in which method thermal energy is transferred in the evaporator unit, in particular from a heat source fluid to the working fluid, the working fluid evaporates at least partially, in particular completely, then the working fluid is compressed in the compressor assembly, in which case the working fluid passes through a plurality of compressor stages in particular in the compressor assembly, then the working fluid is at least partially, in particular completely, condensed in the condenser unit for the release of thermal energy, in particular to a sink fluid, the working fluid is subsequently supplied again to the evaporator unit via one return pipe, in which case the working fluid expands in an expansion assembly provided in the return pipe and having one or more expansion stages.

[0003] A heat pump operates on the fundamental principle of absorbing thermal energy from a heat source through the evaporation of a working fluid and releasing it into a heat sink, such as a sink fluid, after compression. For this purpose, the working fluid, which normally exists in a gaseous state after absorbing heat and possesses the absorbed thermal energy, is pressurized to a higher pressure level by a compressor and then condensed at a condensation temperature higher than its evaporation temperature. Here, the fundamental property of fluids that both evaporation and condensation temperatures increase with increasing pressure is utilized. To return the working fluid to its initial state at the end of its cycle, it is expanded, thereby decreasing its pressure and temperature again.

[0004] The coefficient of performance (COP) plays a special role in determining the efficiency of a heat pump. Here, the coefficient of performance is defined as the ratio of output to input. Output corresponds to the amount of heat released to the heat sink, for example, the sink fluid. Input is determined by the work done by the compressor. In this case, the greater the difference between the evaporation temperature and condensation temperature of the fluid, that is, the higher the temperature of the working fluid when heat is transferred to the sink fluid, the lower the efficiency of the heat pump, because a higher input is required to compress the working fluid to the corresponding pressure level.

[0005] Heat pumps are expected to be increasingly used in industrial processes, such as for generating steam in industrial plants. In this case, the sink fluid, in this case water, is heated to a temperature of approximately 130-140°C. This naturally requires the corresponding compression of the working fluid, so the coefficient of performance of such high-temperature heat pumps is inherently low. [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a heat pump assembly of the type described above that can efficiently heat a sink fluid to a high temperature, and a method for operating such a heat pump assembly. [Means for solving the problem]

[0007] According to a first aspect of the present invention, this problem is solved by having a heat pump assembly of the type described at the beginning, wherein the heat pump assembly has at least one flash gas pipe, and the return pipe of this flash gas pipe is connected to the compressor assembly in parallel with the evaporator unit, so that the gaseous component of the working fluid (flash gas) can be supplied to the compressor assembly from the return pipe, bypassing the evaporator unit.

[0008] In response to this, the problems in the type of method described at the beginning are solved, according to a first aspect of the present invention, by separating the gaseous component of the working fluid from the liquid component of the working fluid as a flash gas from the return piping and supplying it to the compressor assembly via at least one flash gas pipe, bypassing the evaporator unit.

[0009] This aspect of the present invention is based on the fundamental idea that the working fluid, after condensation in the condensing unit, still possesses a high temperature that allows its heat to be utilized. In particular, if the working fluid is in a completely liquid state after leaving the condensing unit, it can be expanded in the first expansion stage of the expansion assembly or in an expansion device located in the flash gas piping, at which point its pressure decreases. As the pressure decreases, the evaporation temperature also decreases, so a portion of the working fluid transitions back to a gaseous phase state as it flows through the first expansion stage. This gaseous component (flash gas) can be separated and supplied directly to the compressor assembly via the flash gas piping, bypassing the evaporator unit. This allows the heat still remaining in the working fluid after the condensing unit to be efficiently utilized because it is still at a high temperature at the pressure at that time, resulting in a significant improvement in the coefficient of performance.

[0010] In another embodiment, the compressor assembly has multiple, in particular, just two compressor stages, and the heat pump assembly includes just one flash gas pipe. In this case, the flash gas pipe can merge into the compressor assembly between two consecutive, i.e., adjacent, compressor stages. In other words, the compressor assembly includes multiple compressor stages, in which the pressure of the working fluid increases in stages. Thus, the flash gas pipe merges into the compressor assembly between two consecutive compressor stages, in which case there exists a working fluid pressure between these compressor stages that corresponds to the pressure in the flash gas pipe.

[0011] This heat pump assembly may also have the following features: that the compressor assembly has multiple, in particular, exactly three or four compressor stages, and the heat pump assembly includes multiple, in particular, exactly two or three parallel flash gas lines, each of which merges into the compressor assembly between consecutive, i.e., adjacent, different compressor stages. In this embodiment, rather than using only one flash gas line to utilize the thermal energy remaining in the working fluid downstream of the condensing unit, multiple flash gas lines are branched substantially in a cascading manner, particularly downstream of different expansion stages of multiple expansion units, or each of the multiple flash gas lines is provided with corresponding expansion means, thereby transferring a portion of the working fluid to a gaseous phase, and supplying this gaseous component as flash gas to the compressor assembly between consecutive, different compressor stages. In particular, different pressures may exist within each flash gas line, corresponding to the pressures present between each compressor stage.

[0012] In response to this, the method according to the present invention allows the gaseous component of the working fluid to be separated in one or more stages, particularly just two or three stages, and supplied to the compressor assembly, particularly between two consecutive compressor stages, by bypassing the evaporator unit through a single flash gas pipe.

[0013] In another embodiment, a separator can be placed in the return piping, configured to separate the gaseous component (flash gas) of the working fluid from the liquid component of the working fluid, and at least one of the flash gas pipes, particularly the sole flash gas pipe, or the first flash gas pipe of a plurality of flash gas pipes, can be extended from this separator, so that the liquid component of the working fluid continues to flow in the return piping and the gaseous component of the working fluid flows in the flash gas pipe. In other words, a separator can be directly provided in the return piping, particularly downstream of the first expansion stage of the expansion assembly, so that the gaseous component of the working fluid is separated from the liquid component of the working fluid. In this case, the separator can have two outlets, one of which is connected to a flash gas pipe through which the gaseous component of the working fluid flows, and the other outlet to which the return piping further extends, through which the liquid component of the working fluid flows.

[0014] At least one flash gas pipe, in particular a second flash gas pipe, or a second and third flash gas pipe, can be branched from the return pipe. A separator can be placed in this one flash gas pipe, or in each of these multiple flash gas pipes, configured to separate the gaseous component of the working fluid (flash gas) from the liquid component of the working fluid, so that the gaseous component of the working fluid can flow further through the flash gas pipe towards the compressor assembly, and the liquid component of the working fluid can be returned to the return pipe. This also makes it possible to place the separator in the flash gas pipe rather than directly in the return pipe, where the gaseous component of the working fluid is separated from the liquid component of the working fluid.

[0015] In this flash gas piping, an expansion device can be installed upstream of the separator, thereby reducing the pressure of the working fluid within the flash gas piping. In other words, an expansion device can be directly installed upstream of the separator in the flash gas piping, which allows a portion of the working fluid to transition from the liquid phase to the gaseous phase due to the pressure reduction and the resulting decrease in evaporation temperature.

[0016] In a preferred embodiment, a first flash gas piping can be extended from a separator located in the return piping. This separator is preferably located downstream of the first expansion stage of the expansion assembly in the return piping. A second flash gas piping and optionally a third flash gas piping can be branched directly from the return piping, in which case each of the second and optionally third flash gas pipings is provided with a separator. Upstream of each of these separators in the second and optionally third flash gas pipings, each flash gas piping is preferably provided with an expansion device. The separator located in the flash gas piping has one (gas) outlet and another (liquid) outlet, and the flash gas piping extends further from this (gas) outlet toward the compressor assembly, through which the gaseous component of the working fluid flows, and its (liquid) outlet is reconnected to the return piping via a return line, through which the liquid component of the working fluid can flow.

[0017] In another embodiment, multiple superheating means for introducing heat to the flash gas can be arranged in at least one flash gas piping, in particular in just one and / or a first flash gas piping. These may include a single superheating heat exchanger located in the flash gas piping. A branch pipe can be branched from the return piping, particularly upstream of the expansion assembly, and this branch pipe joins a superheating heat exchanger so that thermal energy can be transferred from the working fluid to the flash gas, thereby superheating the flash gas. This means that the high temperature of the working fluid after it leaves the condensing unit can be further utilized, thereby introducing thermal energy to the flash gas and superheating the flash gas.

[0018] In response to this, the method according to the present invention can be configured such that the flash gas is superheated in at least one, in particular just one, and / or first flash gas piping, in particular by heat transfer from the working fluid branched from the return piping. This superheating supplies additional thermal energy from the working fluid to the flash gas before it is introduced into the compressor assembly, thereby further increasing the coefficient of performance of the heat pump assembly.

[0019] This compressor assembly can be configured as a turbo compressor having multiple compressor stages. In this case, there are different pressures or pressure levels between each compressor stage, and as a result, the pressure of the working fluid increases sequentially as it passes through. If the heat pump assembly includes multiple flash gas lines, it is preferable that the first flash gas line joins the compressor assembly at a higher pressure level than the second flash gas line. Correspondingly, in the return piping, viewed from the outlet of the condensing unit, the first flash gas line branches off first, followed by the second flash gas line and possibly a third flash gas line and several further flash gas lines.

[0020] This expansion assembly may include multiple expansion stages, in which case each expansion stage may be configured as an adjustable throttle, thereby allowing adjustment of the flow rate of the working fluid. Specifically, this expansion assembly may have just two expansion stages, which are arranged in succession in the return piping.

[0021] According to a second aspect of the present invention, the problem of the present invention in the type of heat pump assembly described at the beginning is solved by providing a plurality of heat exchange means in which the heat pump assembly further has sink fluid supply piping that joins a condensing unit, and these heat exchange means are configured to transfer thermal energy in the return piping, particularly downstream of the expansion assembly, i.e., from the working fluid flowing between the two expansion stages of the expansion assembly, to the sink fluid flowing through the sink fluid supply piping toward the condensing unit.

[0022] In response to this, the problem of the present invention in the type of method described at the beginning is solved by heating the sink fluid before it flows into the condensing unit through heat exchange with the working fluid flowing in the return pipe.

[0023] The basic idea of ​​this aspect of the present invention is to improve the coefficient of performance of the heat pump assembly by preheating at least a portion of the sink fluid flowing toward the condensing unit before it flows into the condensing unit, for which heat that remains in the working fluid after flowing through the condensing unit is utilized.

[0024] Specifically, these multiple heat exchange means can include a single heat exchanger. This heat exchanger can be located in the return piping, particularly downstream of the expansion assembly, or between the two expansion stages of the expansion assembly. Furthermore, a sink fluid supply pipe, or a bypass pipe branching off from it and rejoining it, can pass through this heat exchanger, thereby transferring thermal energy from the working fluid to the sink fluid.

[0025] In a preferred embodiment, one bypass pipe extends through this heat exchanger. In this case, it is not necessary for all of the sink fluid to pass through this heat exchanger, and only a part of it is passed through. In this sink fluid supply pipe, between the branch position and the confluence position of the bypass pipe, that is, in this bypass pipe, control means for flow rate adjustment for adjusting the volume flow rate of the sink fluid flowing through this bypass pipe can be arranged. Correspondingly, only the part of the sink fluid that is branched from the sink fluid supply pipe by this bypass pipe is heated within this heat exchanger.

[0026] In principle, it is also conceivable to branch a partial volume flow of the working fluid from the return pipe, supply this to one heat exchanger disposed in the sink fluid supply pipe or the bypass pipe, and thus prevent this heat exchanger from being directly disposed in the return pipe. In this case, only a part of the working fluid flowing through the return pipe is used for heat exchange with the sink fluid. In other words, in this case, these heat exchange means include one working fluid bypass pipe that branches from the return pipe and rejoins the return pipe again, and this passes through the heat exchanger.

[0027] In another embodiment of the heat pump assembly according to two aspects of the present invention, one heat exchanger can be arranged in the sink fluid supply pipe, and this heat exchanger is connected to the piping system of the heat source fluid so as to be able to transfer heat from the heat source fluid to the sink fluid. In this way, by directly using the heat source fluid for preheating the sink fluid, heat exchange can be performed before the sink fluid flows into the condensation unit. Correspondingly, in the method according to the present invention, the sink fluid can be heated by heat exchange with the heat source fluid before flowing into the condensation unit.

[0028] In a specific embodiment, the heat exchange device in the sink fluid supply pipe can be arranged upstream of the heating of the sink fluid by heat exchange with the working fluid in the return pipe. In other words, in the first step, the sink fluid can be preheated by heat transfer from the heat source fluid, and in the second step, at least a part of the sink fluid can be heated by heat transfer from the working fluid present in the return pipe.

[0029] One additional heating pipe can be branched from the return pipe, particularly between two expansion stages of the expansion assembly, and this additional heating pipe merges into a heat exchange unit arranged between the evaporator unit and the compressor assembly, thereby transferring thermal energy to the working fluid flowing from the evaporator unit to the compressor assembly and particularly superheating the working fluid. In other words, this heat exchange unit can be arranged in the working fluid pipe connecting the outlet of the evaporator unit to the inlet of the compressor assembly. One reverse flow pipe can extend from this heat exchange unit, and this reverse flow pipe merges back into the return pipe particularly downstream of the expansion assembly, allowing the branched working fluid to flow back into the return pipe again. This configuration shows a further possibility of optimizing the coefficient of performance of the heat pump assembly because the heat still remaining in the working fluid in the return pipe can be efficiently utilized in such a way.

[0030] Correspondingly, the method according to the invention can be characterized in that the working fluid is heated, particularly superheated, by heat exchange with the working fluid branched from the return pipe after leaving the evaporator unit and before flowing into the compressor assembly.

[0031] This heat pump assembly can include one heat removal device arranged upstream of the condenser unit so as to be able to lower the temperature of the working fluid to the condensation temperature. This heat removal device can be arranged in the working fluid pipe connecting the outlet of the compressor assembly to the inlet of the condenser unit. Correspondingly, in the method according to the invention, the temperature of the working fluid can be lowered to its condensation temperature before the working fluid flows into the condenser unit.

[0032] Further embodiments of the present invention should be seen in the following description of embodiments with reference to the dependent claims and drawings. The drawings show the following: [Brief explanation of the drawing]

[0033] [Figure 1] Schematic diagram of a first embodiment of the heat pump assembly according to the present invention [Figure 2] Schematic diagram of a second embodiment of the heat pump assembly according to the present invention [Figure 3] Schematic diagram of a third embodiment of the heat pump assembly according to the present invention [Modes for carrying out the invention]

[0034] Figure 1 shows a high-temperature heat pump assembly 1 according to the present invention, which has a fluid circuit for the working fluid. This fluid circuit includes an evaporator unit 2 for transferring thermal energy from a heat source, in this case a heat source fluid, to the working fluid. The evaporator unit 2 is configured here as a counterflow heat exchanger, to which a heat source fluid supply pipe 3 joins, and to which a heat source fluid return pipe 4 exits.

[0035] The fluid circuit further includes a compressor assembly 5 located downstream of the evaporator unit 2 to compress the working fluid. The compressor assembly 5 is configured as a turbo compressor and includes two compressor stages 6a and 6b. The two compressor stages 6a and 6b are driven here by a motor 7.

[0036] The fluid circuit further includes a condensing unit 8 located downstream of the compressor assembly 5, which is configured here as a multi-stage heat exchanger. In the condensing unit 8, thermal energy is released from the working fluid to the sink fluid, in this case water, to evaporate the sink fluid. For this purpose, a sink fluid supply pipe 9 is connected to the condensing unit 8 to supply the sink fluid into the condensing unit 8. A sink fluid steam pipe 10 exits the condensing unit 8 to further transport the evaporated sink fluid to the corresponding equipment where it is needed. A heat removal device (not shown) may be located upstream of the condensing unit 8, which cools the working fluid to its condensation temperature.

[0037] After flowing through the condensing unit 8, the working fluid is at least substantially liquid and flows through the return pipe 11, which connects the outlet of the condensing unit 8 to the inlet of the evaporator unit 2.

[0038] The return pipe 11 is provided with one expansion assembly 12, which in this example has two expansion stages 13a and 13b for expanding the working fluid.

[0039] The working fluid, guided through this fluid circuit, receives thermal energy from the heat source fluid in the evaporator unit 2, during which time it evaporates at least partially, and especially completely. Subsequently, the working fluid is compressed to a higher pressure level in the compressor assembly 5, resulting in a rise in its temperature, and then condenses at least partially, and especially completely, in the condensation unit 8 to release thermal energy to the sink fluid. The working fluid is then returned to the evaporator unit 2 via the return pipe 11, in which case it expands in two expansion stages 13a and 13b of the expansion assembly 12 located in the return pipe 11.

[0040] The heat pump assembly 1 further has a flash gas pipe 14, which is located downstream of the first expansion stage 13a of the expansion assembly 12 and connects to the compressor assembly 5 via a return pipe 11. In this way, the gaseous component of the working fluid (flash gas) can be supplied to the compressor assembly 5 from the return pipe 11, bypassing the evaporator unit 2. Specifically, the flash gas pipe 14 is connected to the compressor assembly 5 between two compressor stages 6a and 6b.

[0041] After flowing through the condensation unit 8, the working fluid, which is completely liquid, partially turns back into a gas at the expansion stage 13a because the boiling point also decreases with the decrease in pressure. To separate the gaseous component (flash gas) of the working fluid, a separator 15 is located downstream of the first expansion stage 13a in the return pipe 11. This separator 15 is configured to separate the gaseous component of the working fluid from the liquid component of the working fluid. A flash gas pipe 14 exits the separator 15, and as a result, the liquid component of the working fluid flows further through the return pipe 11, while the gaseous component of the working fluid flows through the flash gas pipe 14 towards the compressor assembly 5.

[0042] The flash gas piping 14 is further equipped with multiple superheating means for introducing additional heat to the flash gas to superheat it. Specifically, these superheating means include one superheating heat exchanger 16. A branch pipe 17 branches off from the return pipe 11 upstream of the first expansion stage 13a, and this branch pipe 17 joins the superheating heat exchanger 16, transferring thermal energy from the working fluid to the flash gas to superheat it. The working fluid flowing through the branch pipe 17 is then returned to the return pipe 11 via a return line 18, which is equipped with an expansion device 19 for expanding the working fluid. The return line 18 joins the return pipe 11 downstream of the first expansion stage 13a.

[0043] Furthermore, the flash gas piping 14 is equipped with a specially adjustable expansion device 20 between the superheating heat exchanger 16 and the compressor assembly 5, which allows the flash gas pressure to be matched to the pressure between the compressor stages 6a and 6b, thereby controlling the volumetric flow rate of flash gas in the flash gas piping 14.

[0044] By separating the gaseous component of the working fluid from the return pipe 11, bypassing the evaporator unit 2, and introducing it to the compressor assembly 5, the heat present in the working fluid after it leaves the condenser unit 8 can be efficiently utilized, thereby improving the coefficient of performance of this heat pump assembly 1.

[0045] From the return pipe 11, an additional heating pipe 21 branches off between the two expansion stages 13a and 13b of the expansion assembly 12. This additional heating pipe joins a heat exchange unit 22 located between the evaporator unit 2 and the compressor assembly 5, thereby transferring thermal energy to the working fluid flowing from the evaporator unit 2 to the compressor assembly 5, and superheating the working fluid. The heat exchange unit 22 is again connected to the return pipe 11 via a backflow pipe 23, so that the working fluid that flows through the heat exchange unit 22 and releases its heat can be guided back to the return pipe 11 via this backflow pipe 23. This backflow pipe also has an expansion device 24 for expanding the working fluid. This backflow pipe 23 joins the return pipe 11 downstream of the expansion assembly 12, that is, downstream of the two expansion stages 13a and 13b.

[0046] Furthermore, a heat exchanger 25 is located in the sink fluid supply piping 9, and this heat exchanger 25 is connected to the heat source fluid piping system so that heat can be transferred from the heat source fluid to the sink fluid. Specifically, for this purpose, a branch (C) is provided in the heat source fluid supply piping 3, which is connected to the inlet (C) of the heat exchanger 25, and a junction (D) is provided in the heat source fluid return piping 4, which is connected to the outlet (D) of the heat exchanger 25. In this way, the sink fluid can be preheated directly by this heat source fluid.

[0047] Figure 2 shows a second embodiment of the high-temperature heat pump assembly according to the present invention. This embodiment differs from the heat pump assembly 1 in Figure 1 in that it includes not just one flash gas pipe 14, but two flash gas pipes 14 and 26 that run parallel to each other. The compressor assembly 5 in this example includes three compressor stages 6a, 6b, and 6c.

[0048] The first flash gas piping 14 extending from the separator 15 to the compressor assembly 5 is configured in the same manner as in the first embodiment shown in Figure 1.

[0049] Downstream of the separator 15 from which the first flash gas pipe 14 exits, a second flash gas pipe 26 branches off from the return pipe 11. This flash gas pipe 26 is initially equipped with an expansion device 27 to reduce the pressure of the working fluid inside the flash gas pipe 26. This lowers the boiling point, and as a result, some of the liquid working fluid transitions back into the gaseous phase.

[0050] In this flash gas piping, a separator 28 is located downstream of the expansion device 27, which is configured to separate the gaseous component of the working fluid from the liquid component of the working fluid. In this way, the gaseous component of the working fluid can flow further through the flash gas piping 26 toward the compressor assembly 5, and the liquid component of the working fluid is returned to the return piping 11 downstream of the second expansion stage 13b via a corresponding return line 29 where a specially adjustable expansion device 30 is located.

[0051] Further downstream of this flash gas piping 26, there is a specially adjustable expansion device 20, similar to the case of the first flash gas piping 14.

[0052] The first flash gas piping 14 joins the compressor assembly 5 between two compressor stages 6b and 6c, while the second flash gas piping 26 joins the compressor assembly 5 between compressor stages 6a and 6b.

[0053] Furthermore, a plurality of heat exchange means are provided, configured to transfer thermal energy from the working fluid flowing in the return pipe 11 to the sink fluid flowing in the sink fluid supply pipe 9. Specifically, these heat exchange means include one heat exchanger 31 located downstream of the first expansion stage 13a of the expansion assembly 12 in the return pipe 11. A bypass pipe 32(E) branches off from the sink fluid supply pipe 9 downstream of this heat exchanger 25, and this bypass pipe 32 passes through the heat exchanger 31 and rejoins the sink fluid supply pipe 9 (F), thereby enabling the transfer of thermal energy from the working fluid to the sink fluid.

[0054] In the sink fluid supply piping 9, a control means 33 for adjusting the volumetric flow rate of the sink fluid flowing through the bypass piping 32 is positioned between the branching point and the confluence point of the bypass piping 32. This control means 33 can be configured, for example, as an adjustable throttle. In this way, the sink fluid can be heated by direct heat exchange with the working fluid in the return piping 11 before it flows into the condensing unit 8, and as a result, the heat present in the working fluid in the return piping 11 can be utilized in a favorable manner, increasing the coefficient of performance of the heat pump assembly 1.

[0055] Figure 3 shows yet another embodiment of the heat pump assembly 1 according to the present invention. This embodiment differs from the embodiment in Figure 2 only in that the heat exchange unit 22, which is located between the evaporator unit 2 and the compressor assembly 5, is omitted, and as a result, the working fluid is not heated between the evaporator unit 2 and the compressor assembly 5. This makes it possible to omit, in some cases, a complex heat removal device, not shown in Figures 1 and 2, which is located upstream of the condensing unit 8 to lower the temperature of the working fluid to its condensation temperature.

[0056] In particular, it has been found that a clearly more favorable coefficient of performance can be obtained by efficiently utilizing the heat that remains in the working fluid even after it leaves the condensing unit 8, via at least one flash gas pipe 14, 26 and the heat exchanger 31. As a result, under certain conditions, superheating of the working fluid downstream of the heat exchanger 22 and the evaporator unit 2 can be omitted. This significantly reduces the equipment technology costs, especially for such heat removal devices.

[0057] Although the present invention has been illustrated and described in more detail by preferred embodiments, the present invention is not limited to the disclosed examples, and those skilled in the art can derive other modifications therefrom without departing from the scope of protection of the present invention.

Claims

1. A heat pump assembly (1) having one fluid circuit for a working fluid, wherein the fluid circuit is One evaporator unit (2) for transferring thermal energy from a heat source, particularly from the heat source fluid to the working fluid, A compressor assembly (5) is located downstream of the evaporator unit (2) to compress the working fluid, A condensing unit (8) is located downstream of the compressor assembly (5) to release thermal energy, particularly to evaporate the sink fluid from the working fluid, preferably the sink fluid. A single return pipe (11) connects the outlet of the condensing unit (8) to the inlet of the evaporator unit (2), An expansion assembly (12) having one or more expansion stages (13a, 13b) is provided in the return pipe (11) to expand the working fluid, In a heat pump assembly (1) including, The heat pump assembly (1) is characterized in that it has at least one flash gas pipe (14, 26), the flash gas pipe has a return pipe (11) connected to the compressor assembly (5) in parallel with the evaporator unit (2), and as a result the gaseous component (flash gas) of the working fluid can be supplied from the return pipe (11) to the compressor assembly (5) by bypassing the evaporator unit (2).

2. A heat pump assembly (1) according to claim 1, The compressor assembly (5) has a plurality of compressor stages (6a, 6b, 6c), the heat pump assembly (1) includes exactly one flash gas pipe (14), and the flash gas pipe (14) merges with the compressor assembly (5) between two consecutive compressor stages (6a, 6b, 6c), or The compressor assembly (5) has a plurality of compressor stages (6a, 6b, 6c), and the heat pump assembly (1) includes a plurality of flash gas pipes (14, 26) that are in particular parallel to each other, and each of these different flash gas pipes (14, 26) joins the compressor assembly (5) between adjacent different compressor stages (6a, 6b, 6c). A heat pump assembly (1) characterized by the following:

3. A heat pump assembly (1) according to claim 1 or 2, wherein in the return pipe (11), a separator (15) configured to separate the gaseous component (flash gas) of the working fluid from the liquid component of the working fluid is located downstream of one expansion stage (13a, 13b) of the expansion assembly (12), and at least one of the flash gas pipes (14), in particular a first flash gas pipe (14) of a plurality of flash gas pipes (14), extends from the separator (15), so that the liquid component of the working fluid continues to flow in the return pipe (11) and the gaseous component of the working fluid can flow in the flash gas pipe (14).

4. A heat pump assembly (1) according to any one of claims 1 to 3, wherein at least one flash gas pipe (26), in particular a second flash gas pipe (26), or second and third flash gas pipes (26) branch off from the return pipe (11), and a separator (28) configured to separate the gaseous component (flash gas) of the working fluid from the liquid component of the working fluid is disposed in the flash gas pipe (26), thereby allowing the gaseous component of the working fluid to flow further through the flash gas pipe (26) toward the compressor assembly (5) and allowing the liquid component of the working fluid to be returned to the return pipe (11), in which case, in particular, an expansion device (27) for reducing the pressure of the working fluid in the flash gas pipe is provided upstream of the separator (28) in the flash gas pipe (26).

5. A heat pump assembly (1) according to any one of claims 1 to 4, wherein at least one flash gas piping (14), in particular just one and / or a first flash gas piping (14), is provided with a plurality of superheating means for introducing heat into the flash gas, in which case each of the superheating means includes one superheating heat exchanger (16), and a branch piping (17) branches off from the return piping (11), preferably upstream of the expansion assembly (12), and the branch piping (17) joins the superheating heat exchanger (16) to transfer thermal energy from the working fluid to the flash gas and superheat the flash gas.

6. A heat pump assembly (1) having a fluid circuit for the working fluid, The fluid circuit is, in particular, according to any one of claims 1 to 5. One evaporator unit (2) for transferring thermal energy from a heat source, particularly from the heat source fluid to the working fluid, A compressor assembly located downstream of the evaporator unit (2), having a plurality of compressor stages (6a, 6b, 6c) in particular for compressing the working fluid, A condensing unit (8) is located downstream of the compressor assembly (5) to release thermal energy from the working fluid to the sink fluid, preferably to evaporate the sink fluid, A single return pipe (11) connects the outlet of the condensing unit (8) to the inlet of the evaporator unit (2), Includes one expansion assembly (12) having one or more expansion stages (13a, 13b) provided in the return pipe (11) for expanding the working fluid, In a heat pump assembly (1) having a single sink fluid supply pipe (9) that connects to the condensing unit (8), A heat pump assembly (1) is characterized in that a plurality of heat exchange means are provided in the return pipe (11), and the plurality of heat exchange means are configured to transfer thermal energy particularly downstream of the expansion assembly (12), that is, from the working fluid flowing between the two expansion stages (13a, 13b) of the expansion assembly (12) to the sink fluid flowing in the sink fluid supply pipe (9).

7. A heat pump assembly (1) according to claim 6, characterized in that the plurality of heat exchange means include one heat exchange device (31).

8. A heat pump assembly (1) according to claim 7, wherein the heat exchanger (31) is located in the return piping (11), particularly downstream of the expansion assembly (12), or between the two expansion stages (13a, 13b) of the expansion assembly (12), and further, the sink fluid supply piping (9), or a bypass piping (32) branching off from there and rejoining it, extends through the heat exchanger (31), thereby enabling the transfer of thermal energy from the working fluid to the sink fluid.

9. A heat pump assembly (1) according to claim 8, wherein a bypass pipe (32) extends through the heat exchanger (31), and in the sink fluid supply pipe (9), a flow rate adjustment control means (33) for adjusting the volumetric flow rate of the sink fluid flowing through the bypass pipe (32) is arranged between the branching position of the bypass pipe (32) and the merging position, i.e., in the bypass pipe (32).

10. A heat pump assembly (1) according to any one of claims 1 to 9, wherein the heat pump assembly (1) has a sink fluid supply pipe (9) that connects to the condensing unit (8), wherein a heat exchanger (25) is arranged in the sink fluid supply pipe, and the heat exchanger (25) is connected to the heat source fluid piping system so as to transfer heat from the heat source fluid to the sink fluid.

11. A heat pump assembly (1) according to any one of claims 1 to 10, wherein an additional heating pipe (21) branches off from the return pipe (11), particularly between two expansion stages (13a, 13b), and the additional heating pipe (21) joins a heat exchange unit (22) located between the evaporator unit (2) and the compressor assembly (5), thereby enabling the transfer of thermal energy to the working fluid flowing from the evaporator unit (2) to the compressor assembly (5), and in particular the superheating of the working fluid, wherein the additional heating pipe (21) joins the return pipe (11) after leaving the heat exchange unit (22), and in this case, preferably a control valve for flow rate adjustment is provided in the additional heating pipe (21).

12. A heat pump assembly (1) according to any one of claims 1 to 11, wherein the compressor assembly (5) includes or is composed of a turbo compressor, and / or a heat removal device is located upstream of the condensing unit (8) to lower the temperature of the working fluid to its condensation temperature.

13. A method for operating a heat pump assembly (1), particularly the heat pump assembly (1) according to any one of claims 1 to 12, The working fluid is guided through a single fluid circuit, in this case, Within the evaporator unit (2), thermal energy is transferred particularly from the heat source fluid to the working fluid, and at this time, at least a portion of the working fluid evaporates. Subsequently, the working fluid is compressed within the compressor assembly (5), in which case the working fluid passes through a number of compressor stages within the compressor assembly (5). Subsequently, the working fluid is at least partially condensed within the condensing unit (8) in order to release thermal energy, particularly to the sink fluid. Subsequently, the working fluid is supplied again to the evaporator unit (2) via a return pipe (11), at which point the working fluid expands within an expansion assembly (12) having one or more expansion stages (13a, 13b). In the method, The gaseous component of the working fluid is separated from the liquid component of the working fluid as flash gas from the return pipe (11) and is supplied to the compressor assembly (5) via at least one flash gas pipe (14, 26), particularly between two compressor stages (6a, 6b, 6c), bypassing the evaporator unit (2). A method characterized by the following:

14. The method according to claim 13, The gaseous component of the working fluid is separated in one stage, or in multiple stages, particularly just two or three stages, and bypasses the evaporator unit (2) to be resupplied to the compressor assembly via the respective flash gas piping (14, 26), and / or The working fluid is completely condensed within the condensing unit (8), and then expands within the expansion stages (13a, 13b) of the expansion assembly (12), during which a portion of the working fluid transitions to a gaseous state, and / or The flash gas is superheated in at least one flash gas pipe (14), particularly just one and / or first flash gas pipe (14), preferably by heat transfer from the working fluid branched from the return pipe (11). A method characterized by the following:

15. A method for operating a heat pump assembly (1), in particular the heat pump assembly (1) according to any one of claims 1 to 12, The working fluid is guided through a single fluid circuit, in this case, In one evaporator unit (2), thermal energy is transferred, in particular, from one heat source fluid to the working fluid, at which time the working fluid is at least partially evaporated. Subsequently, the working fluid is compressed in a single compression assembly, particularly including multiple compressor stages (6a, 6b, 6c). Subsequently, the working fluid is at least partially condensed in one condensation unit (8) to release thermal energy to the sink fluid. Subsequently, the working fluid is supplied again to the evaporator unit (2) via a return pipe (11), at which point the working fluid expands within an expansion assembly (12) having one or more expansion stages (13a, 13b). In particular, in the method according to claim 13 or 14, A method characterized in that the sink fluid is heated by heat exchange with the working fluid flowing through the return pipe (11) before it flows into the condensing unit (8).

16. A method according to claim 15, characterized in that only the portion of the sink fluid that is branched off from the sink fluid supply pipe (9) by a single bypass pipe (32) is heated.

17. A method according to any one of claims 13 to 16, The sink fluid is heated by heat exchange with the heat source fluid before it flows into the condensing unit (8), and / or The working fluid, after leaving the evaporator unit (2) and before flowing into the compressor assembly (5), is heated, particularly superheated, by heat exchange with the working fluid branched from the return pipe (11), and / or The temperature of the working fluid is lowered to its condensation temperature before it flows into the condensation unit (8). A method characterized by the following:

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