Heat pump

Abstract

A heat pump (100) with an evaporator (50) for evaporating a fluid in order to obtain an evaporated fluid is described, the evaporator (50) having an evaporator sump (52); with a condenser (60) for condensing a compressed fluid, the condenser (60) having a condenser sump (64); with a compressor having a first compressor stage (10) and a second compressor stage (20), the compressor being arranged in the flow direction of the evaporated fluid during operation of the heat pump (100) between the evaporator (50) and the condenser (60) and being designed to compress the evaporated fluid in order to obtain the compressed fluid; with a container (45) for collecting an intermediate cooling fluid; and with a heat exchanger (82) having a pipe (56) which is designed such that the intermediate cooling fluid flows through it from the container (45), the pipe (56) being arranged in a flow region (11) between the first compressor stage (10) and the second compressor stage (20) in order to cool vaporous fluid in the flow region (11). Furthermore, methods for operating and producing the heat pump are described.

Description

[0001] heat pump

[0002] Description

[0003] The present invention relates to the field of heat pumps and, in particular, to concepts for improving the efficiency of a heat pump.

[0004] EP 3 203 164 describes a heat pump. Fig. 20 shows the prior art from EP 3 203 164. The heat pump of EP 3 203 164 is operated with water as the refrigerant. The water is fed from the sump of the condenser 6' through the supply line 7T to the sump of the intercooler. From the sump of the intercooler, the supply line 7T goes to the sump of the evaporator 2', thereby providing a return of the refrigerant. From the sump 4a' of the intercooler 4', the further supply line 72' goes to the sump of the evaporator 2', thereby providing a return of the refrigerant to the evaporator. The pump 4c' directs the cooling water to the top of the intercooler tank 41' for sprinkling and cooling the superheated water vapor leaving the compressor 3'. EP 3 203 164 discloses direct cooling with direct irrigation.In direct sprinkling, the superheated steam flowing from the first compressor is cooled to saturated steam temperature by sprinkling it with water from the sump of the intercooler. This sprinkling can cause droplets to form, which are then entrained by the steam toward the second compressor 5', potentially damaging the impeller due to droplet impact. Furthermore, the superheated steam is only cooled in the intercooler. The water collected in the sump of the intercooler is therefore already almost at saturated steam temperature. Cooling the superheated steam to saturated steam temperature requires a relatively large surface area and a long contact time between the water and steam. Typically, refrigeration systems are limited to a limited output range. To respond to both higher and lower cooling capacities simultaneously, the compressors must be switched on and off frequently.In EP 3 203 164 B, for example, a flap is provided between the different compressors.

[0005] The publication "Novel Turbo Compressor for Heat Pump Using Water as Refrigerant and Lubricant" by T. Shoyama et al. (2019, IOP Conf.: Mater. Sci. Eng. 604 01 1010) describes a compressor for a heat pump with a steam bypass V0 that taps the steam directly after the compressor (see Fig. 21). The steam flows from the outlet of the second compressor C2 back to the inlet of the first compressor C1.

[0006] Typically, the power consumption of the first compressor stage serves as the reference variable for the second compressor stage. This results in the two compressor stages (first and second compressor stages) contributing a similar pressure ratio to the overall pressure ratio, as both rotate at approximately the same speed. As a result, the second compressor is not optimally supplied with air. This becomes particularly problematic at high pressure ratios because the ambient temperature and the control of the second compressor result in a variance in vapor volume flows due to the power consumption of the first compressor. Condensation and re-evaporation in the intermediate circuit leads to a thermodynamic loss, meaning that the pressure ratios of the compressor stages do not fully contribute to the overall compression ratio. This is particularly problematic for the second compressor.

[0007] The object of the present invention is to provide an improved heat pump which, in particular, has an improved concept for heat exchange of a fluid circulating in the heat pump, such as a cooling liquid.

[0008] This object is achieved by a heat pump according to patent claim 1.

[0009] The heat pump according to the present invention comprises an evaporator for evaporating a fluid to obtain an evaporated fluid, the evaporator having an evaporator sump, and a condenser for condensing a compressed fluid, the condenser having a condenser sump.The heat pump also comprises a compressor with a first compressor stage and a second compressor stage, wherein the compressor is arranged between the evaporator and the condenser in the flow direction of the evaporated fluid during operation of the heat pump and is designed to compress the evaporated fluid to obtain the compressed fluid; a container for collecting an intercooling fluid; and a heat exchanger with a pipeline designed to be flowed through by the intercooling fluid from the container, wherein the pipeline is arranged in a flow region between the first compressor stage and the second compressor stage in order to cool vaporous fluid in the flow region. It is understood that individual aspects described with regard to the heat pump can also be implemented as a method step, and vice versa. Further details are discussed in the following image description.

[0010] Preferred embodiments of the present invention are explained in detail below with reference to the accompanying drawings. They show:

[0011] Fig. 1 is a hydraulic diagram of the heat pump according to the invention;

[0012] Fig. 2 is an enlarged section of the hydraulic diagram according to Fig. 1, showing a steam flap (upper line) and a steam bypass flap (lower line);

[0013] Fig. 3 shows a schematic test bench used to test the functionality of the heat pump compressors under real operating conditions;

[0014] Fig. 4 shows a schematic structure of an N-stage compression, where N=3 in the case shown;

[0015] Fig. 5 a hydraulic diagram of the N-stage compression;

[0016] Fig. 6 is a three-dimensional view of the heat pump according to the invention;

[0017] Fig. 7 a top view (Fig. 7a) and a side view (Fig. 7b) of the cross-section reducing element and a connection of the cross-section reducing element (Fig. 7c);

[0018] Fig. 8 is a hydraulic diagram showing an indirect intermediate cooling circuit;

[0019] Fig. 9 a hydraulic diagram of the indirect intermediate cooling with indirect heat exchanger;

[0020] Fig. 10 is a sketch of a side view of a heat exchanger tube; Fig. 11 is a diametrical perspective view of the heat exchanger;

[0021] Fig. 12 is a hydraulic diagram showing a feed of the intercooler, the intercooler being fed from the evaporator sump;

[0022] Fig. 13 is a hydraulic diagram showing a feed of the intermediate cooling system, with a sketched heat exchanger, whereby the intermediate cooling system is fed from the evaporator sump;

[0023] Fig. 14 is a hydraulic diagram showing a feed of the intermediate cooling system, with additional filler bodies and / or additional intermediate cooling systems, the intermediate cooling being fed from the evaporator sump;

[0024] Fig. 15 a compressor characteristic map;

[0025] Fig. 16 a three-dimensional envelope surface over a corrected mass flow;

[0026] Fig. 17 a three-dimensional representation for determining the volume flow to determine the corrected mass flow;

[0027] Fig. 18 is a hydraulic diagram highlighting temperature sensors for controlling the second compressor;

[0028] Fig. 19 Scheme to illustrate a control of the compressor stages of the heat pump;

[0029] Fig. 20 is a hydraulic diagram of a heat pump known from the prior art; and

[0030] Fig. 21 shows a hydraulic diagram of a prior art heat pump with a steam bypass. Individual aspects of the invention described herein are described below in Figs. 1 to 15. In the present application, identical reference numerals refer to identical or equivalent elements, although not all reference numerals need to be shown again in all drawings if they are repeated.

[0031] The heat pump 100 according to the invention is described in conjunction with the attached Figures 1 to 19, with individual aspects of the heat pump according to the invention being considered from different perspectives in the various Figures 1 to 19 in order to highlight the individual aspects of the embodiments of the heat pump according to the invention in a comprehensive overview. The individual aspects of the embodiments can be interchanged with one another at will.

[0032] Fig. 1 shows a hydraulic diagram of the heat pump 100 according to the invention. The hydraulic diagram according to Fig. 1 shows a first compressor stage 10 and a second compressor stage 20. The first compressor stage 10 and the second compressor stage 20 are connected to each other via a steam channel 30. The steam channel preferably has a curved shape with a depression 32. Mathematically speaking, the steam channel has at least one inflection point in the depression 32, wherein at least one inflection point, a curvature is zero. According to the hydraulic diagram according to Fig. 1, an intercooler 40 is arranged in the depression 32. The intercooler 40 comprises an operating element 42 and an intercooler sump 44.The intercooler sump 44 for collecting fluid and the active element 42 of the intercooler 40 are coupled to one another via a first intercooler line 46. Fluid from the intercooler sump 44 can be guided via the first intercooler line 46 to the active element 42 in order to spray compressed fluid from the first compressor stage 10, which is guided in particular in the steam channel 30 to the second compressor stage 20, for the purpose of cooling. Furthermore, a second intercooler line 48 is provided starting from the intercooler sump 44. The second intercooler line 48 leads from the intercooler sump 44 to a ball bearing adapter 49 for cooling the ball bearing adapter 49.

[0033] The hydraulic diagram according to Fig. 1 further shows an evaporator 50 assigned to the first compressor stage 10. The evaporator 50 comprises an evaporator sump 52. The evaporator 50 comprises, above the evaporator sump 52, an upper evaporator part 54 in which the first compressor stage 10 is arranged. In the evaporator 50, above the evaporator sump 52, a pipeline 56 is arranged, according to the cross-section shown in the hydraulic diagram according to Fig. 1, in a matrix-like manner above the evaporator sump 52. The fluid to be cooled can flow through the pipeline 56 above the evaporator sump 52. A sprinkler device 58 is arranged above the pipeline to sprinkle the pipeline 56 with fluid from the evaporator sump 52. A first evaporator line 59 is provided from the evaporator sump 52 to the sprinkler device 58, which conducts fluid from the evaporator sump 52 to the sprinkler device 58.After the pipeline 56 has been sprinkled, the fluid discharged via the sprinkling device 58 can be collected in the evaporator sump 52 and fed again into a circuit of the heat pump 100.

[0034] The hydraulic diagram according to Fig. 1 further shows a bypass channel 62 between the first compressor stage 10 and a condenser 60 for bypassing the second compressor stage 20. Compressed fluid can be conducted directly to the condenser 60 via the bypass channel 62 after exiting the first compressor stage 10. The condenser 60 includes a condenser sump 64 for collecting fluid. A pipe 56 is arranged above the condenser sump 64. However, the pipe 56 assigned to the condenser does not have a sprinkler device. The fluid to be heated flows through the pipe 56 assigned to the condenser 60.

[0035] Further features of the hydraulic diagram according to Fig. 1 will be described below in connection with the further advantageous embodiments of the heat pump 100.

[0036] Fig. 2 shows an enlarged section of the hydraulic diagram of Fig. 1, showing a cross-section reduction element 70 (upper branch) and a vapor transfer flap 90 (lower branch). When the vapor transfer flap 90 is open, vaporous fluid can be guided from the condenser 60 into the evaporator 50 via a vapor guide line 92. When the cross-section reduction element 70 is open, vaporous fluid can be guided directly to the condenser 60 via the bypass channel 62.

[0037] According to a preferred embodiment, the heat pump 100 comprises the

[0038] Evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has the evaporator sump 52. The heat pump 100 further comprises the condenser 60 for condensing evaporated fluid compressed by an N-stage compressor 10, 80, 20, wherein the condenser 60 has a condenser sump 64, a condensation region 66, and a holding region 67 for holding a vaporous fluid still remaining after the condensation region 66. The N-stage compressor 10, 20, 80 comprises N compressors, where N is a natural number greater than or equal to one, wherein the N-stage compressor 10, 20, 80 is arranged between the evaporator 50 and the condenser 60. In addition, the heat pump 100 includes the vapor channel 30, which couples at least two of the N compressors of the N-stage compressor 10, 20, 80 between the evaporator 50 and the condenser 60. In Fig.For example, Fig. 4 shows an N-stage compressor, 10, 20, 80, where N=3. Furthermore, the heat pump 100 includes a vapor guide line 92 arranged between the condenser 60 and the evaporator 50 to guide vaporous fluid from the holding area 67 of the condenser 60 into the evaporator 50. Figs. 2 and 4, for example, show a single vapor guide line 92, in each of which the vapor transfer flap 90 is arranged.

[0039] Fig. 3 shows a schematic test bench used to test the functionality of a single compressor of the heat pump 100 under real operating conditions. According to the test bench 300 from Fig. 3, N=1. The test bench 300 comprises a compressor 301 to be tested and at least one pressure sensor 302 for measuring a compression pressure of the compressed fluid. The test bench 300 also comprises at least one temperature sensor 303 for measuring the temperature of the compressed fluid. The at least one pressure sensor 302 and the at least one temperature sensor 303 are arranged near the compressor 301 to be tested. A fluid line 15 leads into the test bench 303 and a fluid line 15 leads out of the test bench 303 in order to supply fluid, in particular cooling water, to the pipe 56 and to discharge it therefrom. The flow in the fluid lines 15 is regulated as a function of a condensing pressure.Preferably, the fluid lines 15 of the test bench 300 are connected to a cold water ring main (at a water temperature of approximately 17°C). The test bench 300 comprises a Jacob tube, which includes a K4 condenser. The Jacob tube preferably has a height of up to 650 mm, in particular 600 mm, and a diameter of up to 600 mm, in particular 500 mm or 550 mm. Furthermore, the test bench comprises another Jacob tube, which has a height of up to 300 mm, in particular 240 mm, and a diameter of up to 600 mm, in particular 500 mm or 550 mm. The Jacob tubes are arranged on a container 45, in which the fluid occupies a fluid level 51. A temperature sensor 303 for measuring a sump temperature in the container 45 is arranged in the container 45. At least one filler body 7 is arranged above the fluid level 51.The filler body 7 preferably comprises a plurality of individual fillers designed to allow the vapor to flow over a larger surface area, allowing it to condense particularly advantageously. The fluid level 51 is set in the container 45 such that, in a pipe 306 that feeds the fluid to the container 45, there is a distance between the liquid fluid and the pipe wall. This distance forms a vapor flow 304 between the water level and the pipe wall. The pipe 306 establishes a connection between an outlet of the compressor 301 to be tested and an inlet to the container 45, in order to return vaporized fluid from the compressor 301 to be tested into the container 45. The pipe 306 is particularly designed in two parts, with a throttle valve 307 arranged between the two pipe sections to adjust a resistance of the vaporized fluid. Furthermore, the evaporation temperature is adjusted by means of the throttle valve 307.A connection 311 of the pipe 306 to the compressor 301 under test is designed such that different cross-sections of different compressors 301 can be connected to the pipe 306. The test bench 300 further comprises a geometric structure that serves as a return line 308 for the condensed fluid from the compressor 301 under test. Furthermore, an effect element 43 for spraying the evaporated fluid is provided in the pipe 306. By means of a pump 310 and an associated line, fluid is pumped from the container 45 into the effect element 42 of the test bench 300. The test bench further comprises a sensor 309, which is in particular a volume flow sensor for measuring a volume flow of the evaporated fluid. A connected control device receives the measurement signals from the volume flow sensor and, among other things, uses this signal to determine the control signal for specifying the compressor's target speed.

[0040] Preferably, in the condenser 60, the holding region 67 is arranged between the condensation region 66 and the condenser sump 64 containing condensed working fluid. An opening 65 of the steam guide line 92 is arranged in the holding region 67 above a fill level 68, in particular a fluid level (51), of the working fluid in the condenser sump 64. The opening 65 of the steam guide line 92 comprises a channel piece that extends through the condenser sump 64 into the holding region 67 in order to conduct evaporated, i.e., uncondensed, fluid via the steam guide line 92 to the evaporator 50.

[0041] Preferably, the condenser sump 64 containing condensed working fluid is arranged in the condenser 60. The steam guide line 92 extends from the holding area 67 through the condenser sump 64 and is led out of the condenser through a wall, preferably a bottom, of the condenser 60. For example, Figs. 2 and 4 show how the steam guide line 92 extends through a bottom of the condenser sump 64. It is conceivable for the steam guide line 92 to extend through a wall, in particular a side wall, through the condenser sump 64.

[0042] Preferably, the condenser 60 has a tube bundle 56a or a spiral tube arrangement 56b through which the liquid to be heated can flow. The tube bundle 56a or the spiral tube arrangement 56b is arranged laterally with respect to the opening 65 of the vapor guide line 92, and an intake nozzle 12 of a compressor of the N-stage compressor 10, 20, 80 is arranged above the tube bundle 56a or the spiral tube arrangement 56b. The tube bundle 56a or the spiral tube arrangement 56b are also referred to herein as pipeline 56.

[0043] Preferably, the steam guide line 92 has an opening 55 into the evaporator 50, with the opening 65 being arranged above the evaporator sump 52 in the evaporator 50. The steam guide line 92 thus has two openings 55, 65, with one opening leading through the condenser sump 64 and the other opening 55 opening into the evaporator 50 above the evaporator sump 52. This can be seen, for example, in Figs. 2 and 4.

[0044] Preferably, a tube bundle 56a for liquid to be cooled and a sprinkling device 58 for sprinkling the tube bundle 56a are arranged in the evaporator 50, wherein the opening 55 of the vapor guide line into the evaporator 50 is arranged such that vaporous fluid entering the evaporator 50 through the opening 55 strikes the tube bundle 56a laterally, and / or that the vaporous fluid exiting the vapor guide line 92 enters a sprinkling region 57 which is at least partially sprinkled by the sprinkling device 58. As can be seen, for example, from Figs. 1, 2 or 4, fluid from the evaporator sump 52 is supplied to the sprinkling device 58 via a first evaporator line 59 between the evaporator sump 52 and the sprinkling device 58.After sprinkling the tube bundle 56a in the evaporator 50, the fluid used for sprinkling can be collected again by the evaporator sump 52 and fed again into a circuit of the heat pump 100.

[0045] Preferably, each compressor of the N-stage compressor 10, 20, 80 has its own shaft, on which the corresponding compressor of the N-stage compressor 10, 20, 80 can be operated and individually controlled during operation. As can be seen from Figs. 1, 2 or 4, for example, each compressor has its own motor M. The compressors of the N-stage compressor 10, 20, 80 can therefore be operated independently of one another or not operated individually at any given time.

[0046] Preferably, the N-stage compressor 10, 20, 80 comprises N compressors connected in series, wherein the vapor guide line 92 is designed as a single vapor guide line 92 and the vaporous fluid, which has been brought from a last stage into the condenser 60, leads from the condenser 60 to the evaporator 50 (see Figs. 2, 4 and 5). Fig. 5 shows a hydraulic diagram of the N-stage compression. In Fig. 5, for example, the cross-section reducing element 70 is shown designed as a valve. The N-stage compressor 10, 20, 80 is shown as N compressors connected in series, which is connected between the evaporator 50 and the condenser 60.

[0047] Preferably, at least two compressors of the N-stage compressor 10, 20, 80 are connected via a vapor channel 30, and an intercooler 40 is arranged between each two compressors to cool the vaporous fluid (see Fig. 4). Each intercooler 40 comprises an effect element 42 and an intercooler sump 44 (see Fig. 4). The intercooler sump 44 is used to collect fluid, and the effect element 42 of the respective intercooler 40 is coupled to each other via a first intercooler line 46, wherein fluid from the intercooler sump 44 can be guided to the effect element 42 via the first intercooler line 46. After passing through the respective effect element 42, the fluid can be collected by the intercooler sump 44. The fluid can then be fed back into a circuit of the heat pump 100. In Fig.5, for the sake of clarity, an intercooler 40 was not shown between the compressors of the N-stage compressor 10, 20, 80.

[0048] Preferably, the intercooler 40 is arranged in a depression 32 of the vapor channel 32, and the intercooler 40 has an intercooling sump 44 and an acting element 42. The acting element 42 is designed to bring about an interaction between an intercooling fluid, which can flow through a supply line, in particular the first intercooler line 46, from the intercooling sump 44 or from the evaporator sump 52 or from the condenser sump 64 into the acting element 42, and a heated vaporous fluid that can be discharged by the compressor. The interaction particularly causes the vaporous fluid discharged by the compressor to be cooled by the intercooler fluid (see Figs. 2 and 4). Before the vaporous fluid in the vapor channel 30 is sucked in by the second compressor stage 20, the vaporous fluid is cooled by the intercooler 40.

[0049] Each intercooler 40 preferably has an intercooling sump 44 and an active element 42 and is arranged in its own depression 32 in the steam channel 30. In particular, each intercooler 40 has its own first intercooler line 46 leading to the active element 42. The first intercooler line 46 can also be referred to as a supply line. Particularly in the case of multiple intercooling sumps 44, the supply lines, i.e., the first intercooler lines 46, can also be interconnected (not shown in the figures), so that the supply lines then form only one supply line in total.

[0050] Preferably, the vapor channel 30 between two compressors has a curved shape with the depression 32, so that fluid from the vapor channel 30 flows past the intercooling sump 44. Condensing fluid can be collected in the intercooling sump 44.

[0051] Preferably, the steam guide line 92 and the steam channel 30 are fluidically separated from one another. By fluidically separated from one another, we mean that the steam guide line 92 and the steam channel 30 are not merged into one another, which would allow mixing of the fluid. Therefore, the steam guide line 92 and the steam channel 30 are drawn in Figs. 2 and 4, for example, with dashed lines to illustrate that the steam guide line 92 and the steam channel 30 are separated from one another. It should be noted that the steam guide line 92 and the steam channel 30 form a circuit in which the fluid circulates in the heat pump 100. The steam channel 30 or the steam channels 30 is / are arranged between the evaporator 50 and the condenser 60 in the upper branch. The steam guide line 92 is arranged between the evaporator 50 and the condenser 60 in the lower branch.

[0052] Preferably, a further N compressors are arranged such that, by switching a switch to an open state, a further compressor of the N compressors is connected in series with a first compressor of the N-stage compressor 10, 20, 80. In Fig. 5, n+1 compressors are schematically sketched with the first compressor 10. The n+1 compressor is drawn with dashed lines, which is intended to indicate the addition of the individual compressors of the N-stage compressor 10, 20, 80. In the present case, the first compressor stage 10 comprises the first compressor. The second compressor stage comprises the second compressor. An n-th compressor stage comprises an n-th compressor, where n is a natural number.

[0053] Preferably, a bypass flap 90 is arranged in the vapor guide line 92. This bypass flap can be moved into an open position, an intermediate position, or a closed position to guide the vaporous fluid from the condenser 60 to the evaporator 50. Similar to the cross-section reduction element 70, the bypass flap 90 can be designed as a diaphragm, a hinged door, a check valve, or a valve, as shown, for example, in Fig. 5. The heat pump 100 further comprises a controller for controlling the bypass flap 90 to the open position, the intermediate position, or the closed position.

[0054] Preferably, the bypass flap 90 is designed as a controlled bypass valve, which can be addressed by the controller to be operated near a boundary line of a compressor characteristic map 170 assigned to the N-stage compressor 10, 20, 80. The design of the bypass flap 90 as a controlled bypass valve is shown, for example, in Fig. 5. The bypass flap 90 can also be referred to here as a vapor transfer flap 90. A compressor characteristic map 170 assigned to the N-stage compressor 10, 20, 80 defines a relationship between a pressure ratio and a mass flow. Such a compressor characteristic map 170 is shown, for example, in Fig. 15.The compressor characteristic map 170 is to be understood as a three-dimensional field, wherein the third dimension is represented by shading in the two-dimensional coordinate system spanned by the pressure ratio PiC and the, in particular corrected, mass flow WcCorr. The pressure ratio PiC describes a ratio of the pressures between evaporator 50 and condenser 60, i.e. between the compressor stages 10, 20, 80. In the compressor characteristic map 170, a surge limit 171 is present, which represents a monotonically increasing function between the mass flow and the pressure ratio. The bridging flap 90 is controlled to ensure that, for a specific mass flow, the pressure ratio is smaller than a limit pressure ratio which, according to the function, is assigned to the specific mass flow. In Fig. 15, the dotted lines 172 show lines of equal speed at a measured evaporation temperature of 18°C.

[0055] Preferably, the controller is configured to transfer the bypass flap 90 into a closed position, an open position, or an intermediate position in order to maintain a load of the N-stage compressor 10, 20, 80 at least at a load setpoint during operation. The surge limit 171 can, in particular, describe the load setpoint, which can, in particular, also be a function dependent on the mass flow WcCorr. In particular, the controller is configured to control the bypass flap 90 such that operation of the heat pump 100 occurs substantially along the surge limit 171 or in a range slightly shifted toward larger mass flows WcCorr, so that operation of the compressor below its absorption limit is advantageously prevented.

[0056] Preferably, the controller is designed to open the bypass flap 90 when the load of the N-stage compressor 10, 20, 80 falls below the load setpoint; or to close the bypass flap 90 when the load of the N-stage compressor 10, 20, 80 exceeds the load setpoint in order to generate an additional load; or to control the intermediate position of the bypass flap 90 depending on whether the load falls below the load setpoint. This makes it possible to operate the heat pump essentially along the surge limit 171. For example, the bypass flap 90 can be moved to the intermediate position when the load of the N-stage compressor 10, 20, 80 deviates from the load setpoint by up to 5%. This can occur starting from the open or closed position of the bypass flap 90.The load setpoint specifies a load of the heat pump 100 during operation, which can be achieved at least by the N-stage compressor 10, 20, 80.

[0057] Preferably, in a two-stage compressor 10, 20, as shown, for example, in Fig. 2, the second compressor is switched off when the bypass flap 90 is open, or in a multi-stage compressor (as shown, for example, in Fig. 4 or 5), all stages except a first stage 10 are switched off when the bypass flap 90 is open. Thus, as soon as all compressor stages except one are switched off, the bypass flap 90 is opened. If at least one further compressor stage is switched on in addition to the one compressor stage that is already in operation, the bypass flap 90 is closed or, if necessary, moved into an intermediate position. For example, the first compressor 10 can be controlled as a function of a speed of a compressor drive in order to adapt the speed of the first compressor stage 10 to a required output of the first compressor 10.

[0058] Fig. 6 shows a three-dimensional view of the heat pump 100 according to the invention. The heat pump 100 comprises the first compressor stage 10 and the second compressor stage 20. The first compressor stage 10 and the second compressor stage 20 are connected to one another via the curved steam channel 30, wherein the steam channel 30 has the intercooler 40. Furthermore, it can be seen from the view in Fig. 6 that the first compressor stage 10 is connected to the condenser 60 via the bridging channel 62, wherein the cross-section reducing element 70 is arranged in the bridging channel 62. The heat pump 100 has already been described with reference to Fig. 1. According to the view in Fig. 6, not all details can be seen which, for example, the hydraulic diagram according to Fig. 1 reveals. The proportions are the same as in Fig.However, as can be seen from the heat pump 100 shown in Fig. 6, for example, the steam channel 30 has an average diameter that corresponds approximately to half the width of the condenser. Therefore, for the description of Fig. 6, reference is also made to the description of Fig. 1 or another figure showing a hydraulic diagram of the heat pump 100 according to the invention. A preferred embodiment of the heat pump 100 comprises an evaporator 50 for evaporating a fluid to obtain evaporated fluid. Furthermore, the heat pump 100 comprises a condenser 60 for condensing a compressed fluid.In addition, the heat pump 100 comprises a compressor with a first compressor stage 10 and a second compressor stage 20. The compressor is arranged between the evaporator 50 and the condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain compressed fluid. According to the proposal, a bridging channel 62 is arranged between the first compressor stage 10 and the condenser 60 to bridge the second compressor stage 20. A cross-section reducing element 70 is arranged in the bridging channel 62 to adjust a cross-section of the bridging channel 62 in order to regulate a flow of compressed fluid from the first compressor stage 10 to the condenser 60.After exiting the first compressor stage 100, compressed fluid can thus be directed directly to the condenser 60, provided the cross-section reduction element 70 assumes an open position. In particular, when the second compressor stage 20 is not in operation, i.e., it is in a switched-off state, the cross-section reduction element 70 is in the open position.

[0059] Preferably, the first compressor stage 10 and the second compressor stage 20 are connected via the steam channel 30 (see also description of Fig. 1). The steam channel 30 is curved, in particular banana-shaped, i.e. bent. The steam channel 30 can have a depression 32 in which a container 45, also called an intercooler sump 44, is arranged to collect fluid which passes through the steam channel 30, provided that the gaseous fluid passing through the steam channel 30 condenses. Because the container 45 is arranged in the depression 32, condensed fluid can be guided into the container 45 automatically by utilizing the force of gravity, in particular without further technical means.

[0060] The bypass channel 62 preferably has an opening into the first compressor stage 10, wherein the first compressor stage 10 has an intake port 12 for sucking in the evaporated fluid and a guide chamber 14 for guiding the vaporous compressed fluid into the bypass channel 62. The intake port 12 can be conical, wherein a first diameter is arranged in an intake region of the intake port 12 for sucking in the fluid and a second diameter of the intake port 12 directly adjoins the guide chamber 14. In particular, the first diameter is larger than the second diameter. In the present case, the first diameter is a maximum diameter 16 and the second diameter is a minimum diameter 17. The guide chamber 14 is arranged transversely, in particular substantially orthogonally, to the second diameter of the intake port 12.

[0061] The condenser 60 preferably has a pipe 56. The pipe 56 is preferably designed as a tube bundle 56a or a spiral tube arrangement 56b through which the liquid to be heated can flow, wherein the tube bundle 56a or the spiral tube arrangement 56b is arranged laterally with respect to a further opening of the bridging channel 62, and wherein an intake nozzle 12 of a compressor of the second compressor stage 20 is arranged above the tube bundle 56a or the spiral tube arrangement 56b.

[0062] Preferably, the further opening of the bridging channel 62 is arranged such that vaporous fluid which passes through the further opening into the condenser 60 strikes the tube bundle 56 laterally. Because the pipe 56, i.e. the tube bundle 56a or the spiral tube arrangement 56b, is arranged laterally with respect to a further opening of the bridging channel 62 in the condenser 60, evaporated compressed fluid, after passing through the bridging channel 62, strikes the pipe 56 directly, where the evaporated and compressed fluid can be cooled. Because the fluid to be heated can flow through the pipe 56, heat is transferred from the evaporated and compressed fluid, which strikes the pipe 56 laterally from the bridging channel 62, via the pipe 56 to the fluid to be heated flowing through the pipe.When the evaporated and compressed fluid impacts the pipe 56, it is cooled, potentially resulting in condensation. A fluid condensed on the pipe 56 may drip into the condenser sump 64, particularly due to gravity.

[0063] Preferably, the cross-section reduction element 70 is designed to assume a closed position or an open position depending on the operation of the second compressor stage 20, wherein the cross-section reduction element 70 is designed to assume the closed position when the second compressor stage 20 is switched on, or to assume the open position when the second compressor stage 20 is switched off. Depending on the operation of the second compressor stage 20, the cross-section reduction element 70 can be transferred to the closed or the open position. It is also conceivable to transfer the cross-section reduction element 70 to an intermediate position, i.e. a position between the open and the closed position, in particular when the second compressor stage 20 is shut down (switched off) or ramped up (switched on).

[0064] Preferably, the cross-section reduction element 70 is preloaded in the closed position by means of a spring element (not shown). If the second compressor stage 20 is shut down, the preloaded spring element can relax, particularly due to the lack of suction of compressed fluid from the first compressor stage 10 through the vapor channel 30, so that the cross-section reduction element 70 transitions to the open position. The compressed fluid from the first compressor stage 10 can then pass through the bypass channel 62, thereby bypassing the second compressor stage 20.

[0065] The cross-section reduction element 70 is preferably a flap or a baffle or a hinged door or a check valve. Fig. 7 shows a plan view of the cross-section reduction element 70 in Fig. 7a and a side view of the cross-section reduction element 70 in Fig. 7b. The cross-section reduction element 70 is arranged in the bridging channel 62 between an outlet of the first compressor stage 10 and the condenser 60 (see, for example, Fig. 1, Fig. 2 or Fig. 4). A diameter 72 of the cross-section reduction element 70 (as shown in Fig. 7a) can correspond to a diameter of the bridging channel 62 or be smaller than the diameter of the bridging channel 62. The diameter of the bridging channel 62 can, for example, be 10 mm. Of course, the diameter of the bridging channel 62 can also have a different diameter. In the side view of the cross-section reduction element 70 (as shown in Fig.7b), the diameter 72 of the cross-section reduction element 70 is smaller than the diameter of the bridging channel 62. Fig. 7c shows a section of Fig. 7b with regard to a connection of the cross-section reduction element 70 for controlling the cross-section reduction element 70 into the open or closed position. Further requirements of the cross-section reduction element 70 can be found, for example, in DIN EN ISO 5211. Preferably, the heat pump 100 has a controller for controlling the cross-section reduction element 70 into the open position or the closed position. Depending on the design of the cross-section reduction element 70 as a flap or panel or wing door or check valve, the controller is designed to control the flap or panel or wing door or check valve. When designed as a panel, for example, the controller is designed to enlarge or reduce a diameter of the panel.

[0066] Preferably, the first compressor stage 10 is designed to build up a maximum deliverable pressure, and the cross-section reduction element 70 is designed to assume the open position when a pressure ratio between the condenser pressure Th and the evaporator pressure Th is less than the maximum deliverable pressure of the first compressor stage, in order to guide compressed fluid from the first compressor stage 10 via the bypass channel 62 to the condenser 60. The pressure ratio between the condenser pressure Th and the evaporator pressure T can be calculated, for example, by measuring temperatures. In particular, the temperature Th in the evaporator sump 52 and the temperature Th in the condenser sump 64 can each be measured in order to determine the pressure ratio between the condenser pressure (Th) and the evaporator pressure Th. In the present case, the measured temperature Th in the evaporator sump 52 is associated with the evaporator pressure Th.In this case, the measured temperature Th in the condenser sump 64 is also associated with the condenser pressure Th. Therefore, the corresponding measured temperature reference symbols Th and Th are used as reference symbols for the respective pressure in the condenser sump 64 and the evaporator sump 52, respectively. For example, Fig. 18 shows where the temperatures Th and Th are measured.

[0067] Preferably, the cross-section reduction element 70 is designed to assume the closed position when the pressure ratio between the condenser pressure Th and the evaporator pressure Th is greater than the maximum deliverable pressure of the first compressor stage 10, in order to guide compressed fluid from the first compressor stage 10 via the vapor channel 30 to the second compressor stage 20. Once it has arrived in the second compressor stage 20, the compressed fluid is further compressed before being fed to the condenser 60 via a guide chamber 14. The guide chamber 14, which is assigned to the condenser 60, is designed analogously to the guide chamber 14, which is assigned to the evaporator 50 in the upper evaporator top section 54. Preferably, the first compressor stage 10 can be operated with N further compressor stages, where N is a natural number greater than or equal to two. In Fig. 4, for example, three compressor stages 10, 20, 80 are shown. According to the illustration in Fig.4, N here is equal to three. It is conceivable to provide any number of compressor stages between the evaporator 50 and the condenser 60. Preferably, the first compressor stage 10 and the N further compressor stages 80, 30 are arranged in series, wherein, with N compressor stages, two adjacent compressor stages are each connected via a steam channel 30 (see Fig. 4, where N=3 is shown, or Fig. 5).

[0068] Fig. 8 shows a hydraulic diagram according to Fig. 1, in which a circuit of an indirect intermediate cooling system 8 is shown. The indirect intermediate cooling system 8 is used in a preferred embodiment of the heat pump 100.

[0069] In the preferred embodiment of the heat pump 100, as shown in Fig. 8, the heat pump 100 comprises the evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has the evaporator sump 52. The heat pump 100 further comprises the condenser 60 for condensing a compressed fluid, wherein the condenser 60 has the condenser sump 64. The heat pump 100 further comprises the compressor with the first compressor stage 10 and the second compressor stage 20, wherein the compressor is arranged between the evaporator 50 and the condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is configured to compress the evaporated fluid to obtain the compressed fluid. The heat pump, as shown in Fig. 8, further comprises a tank 45 for collecting an intercooling fluid. In particular, the container 45 is an intermediate cooling sump 44.The heat pump further comprises a heat exchanger 82 with a pipe 56 designed to be flowed through by the intercooling fluid from the container 45, wherein the pipe 56 is arranged in a flow region 11 between the first compressor stage 10 and the second compressor stage 20 in order to cool vaporous fluid in the flow region 11. In Fig. 8, for example, it is shown that the heat exchanger 82 is arranged around an intake port 12 of the first compressor stage 10. In other words, according to the embodiment of Fig. 8, the pipe 56 is arranged in the region of the first compressor stage 10. As shown in Fig. 14, the heat exchanger 82 can be arranged for indirect cooling between the first compressor stage 10 and the second compressor stage 20, in particular where an intercooler 40 and / or a further intercooler 4 and / or a still further intercooler 5 can be provided.

[0070] Preferably, the pipe 56 is metallic, preferably the pipe 56 comprises stainless steel and / or copper. The metallic pipe 56 improves heat transfer between the fluid inside the pipe 56 and the fluid outside the pipe 56.

[0071] The pipe 56 of the heat exchanger 82 is shown, for example, in Figs. 8 to 10. Preferably, the pipe 56 of the heat exchanger 82 has a region in which the pipe 56 runs in a spiral or spring-shaped manner, wherein the spring-shaped or spiral-shaped region has turns 83 with different turn spacings. In a spring-shaped pipe 56, a diameter is constant from one turn to the next. In a spiral-shaped pipe 56, a diameter of one turn differs from the diameter of a subsequent turn. A spiral-shaped pipe 56 can be designed as a conical spiral. A spring-shaped pipe 56 is created by a central projection of a helical line 101 onto a plane perpendicular to the screw axis 102, as shown, for example, in Fig. 10. Fig. 10 schematically branches off the heat exchanger 82.

[0072] Preferably, the first compressor stage 10 has an intake port 12 for sucking in the evaporated fluid and a guide chamber 14 for directing the vaporous fluid into the flow region 11. The flow region 11 comprises a volume of an upper evaporator part 54, the vapor channel 30, and the bypass channel 62. The flow region 11 comprises those regions of the heat pump 100 into which evaporated and compressed fluid can flow.

[0073] As shown, for example, in Figs. 8 and 9, the pipeline 56 of the heat exchanger 82 is arranged around the intake port 12 of the first compressor stage 10, wherein a winding distance between two windings 83 in an inflow region of the vaporous fluid of the first compressor stage 10 is greater than in an outflow region of the vaporous fluid into the guide chamber 14. This can be seen, for example, in Figs. 8 and 9. Because the winding distance between two windings 83 is greater in an inflow region, the flow velocity of the vapor is slowed down only slightly. In the outflow region of the vaporous fluid into the guide chamber 14, the winding distance between two windings 83 is greater in order to improve, in particular to increase, the cooling of the vapor.

[0074] Fig. 1 1, for example, shows a diametrical perspective view of the heat exchanger 82. Fig. 1 1 shows that it is also conceivable that in the outflow region of the vaporous fluid from the guide chamber 14, the winding distance between two windings 83 is smaller than in the inflow region.

[0075] Preferably, a vapor channel 30 is arranged between the pipeline 56 and the container 45, wherein the outflow region 11, in particular which is also referred to as flow region 11, is connected to the vapor channel 30 in order to conduct the vaporous fluid via the vapor channel 30 through the container 45. "Conducting through the container 45" is to be understood as "conducting over and beyond the container 45". The vaporous fluid is drawn in by the second compressor during operation of the second compressor stage 20. As a result, the vaporous fluid is conducted through the vapor channel 30, as can be seen, for example, in Fig. 8.

[0076] Preferably, a fluid conduit 15 extends laterally from the outflow region 11 into the vapor channel 30 in order to supply the intercooling fluid flowing through the heat exchanger 82 to the container 45 via the vapor channel 30 (see Fig. 8). The outflow region 11 extends from an outlet of the first compressor stage into the vapor channel 30 and into the evaporator section 54. The fluid conduit 15 extends through a wall, in particular a bottom, of the upper evaporator section 54. The intercooling fluid flowing through the heat exchanger 82 collects in a bottom region of the upper evaporator section 54 and forms a fluid level 51. If the fluid level 51 of the upper evaporator part 54 is above the extension of the fluid line channel 15 through the wall, the intermediate cooling fluid can flow into the vapor channel 30 via the fluid line channel 15, in particular due to gravity.

[0077] Preferably, the intake manifold 12 has a funnel shape, which has a maximum diameter 16 and a minimum diameter 17 opposite one another, wherein the guide chamber 14 for guiding the compressed vaporous fluid extends axially to the minimum diameter 17 of the funnel shape. The maximum diameter 16 can be adjacent to the bottom of the upper evaporator section 54, whereby the intercooling fluid flowing through the heat exchanger 82 is collected in the bottom region outside the intake manifold 12 of the first compressor stage 10 (see Fig. 8).

[0078] Preferably, the guide chamber 14 is curved at one end, which merges into the upper evaporator part 54, in order to guide the vaporous fluid flowing through the guide chamber 14 in a direction opposite to a gas flow direction in the intake manifold. In particular, the vaporous fluid leaving the guide chamber 14 is directed into the vapor channel 30 if the second compressor stage is in operation, or into the vapor guide line 92 if the second compressor stage is not in operation.

[0079] Preferably, the guide chamber 14 has a volume with a circle or an oval as its base area. The guide chamber 14 is arranged substantially perpendicular to the minimum diameter 16 of the intake manifold 12 of the first compressor stage 10. The guide chamber is arranged, in particular, in the upper evaporator section 54. Furthermore, the second compressor stage 20 also has a guide chamber 14, which is arranged substantially perpendicular to the minimum diameter 16 of the intake manifold 12 of the second compressor stage 20. The guide chamber 14 of the first or second compressor stage 10, 20 can also have any other desired base area.

[0080] Preferably, a further heat exchanger 82 is arranged in the steam channel 30 at a distance from the outflow region 11. The further heat exchanger 82 is preferably arranged in an intake port 12 of the second compressor stage 20. The first and second compressor stages 10, 20 are connected by the steam channel 30, wherein the steam channel 30 is arranged between a pressure side of the first compressor stage 10 and a suction side of the second compressor stage 20. The steam channel 30 preferably has a curved shape with a depression 32. The container 45 is preferably arranged in the depression 32 so that liquid intercooling fluid flows from the steam channel 30 into the container 45. This can be seen, for example, in Fig. 8.

[0081] Preferably, the heat exchanger 82 and / or the further heat exchanger

[0082] 82 has on its outer surface an at least partially contoured outer surface which is in contact with the vaporous fluid in order to improve heat transfer between the heat carrier 82 and the vaporous fluid. Preferably, the heat exchanger 82 and / or the further heat exchanger 82 has / have on its inner surface an at least partially contoured inner surface which is in contact with the fluid from the container 45 in order to bring about the formation of a turbulent flow on its inner surface. The contoured inner and / or outer surfaces can have grooves and / or reliefs, i.e. recesses / elevations of any shape.

[0083] For self-regulation of a fluid fill level, the condenser sump 64 and / or the evaporator sump 52 and / or the container 45 are preferably each fluid-conductingly connected to one another via a fluid line 15, such that the fluid level 51 of the individual sumps 52, 45, 64 is regulated, in particular only by utilizing gravity. In other words, the fluid level 51 of the individual sumps 52, 45, 64 is passively adjusted due to the geometric arrangement and the connection of the individual sumps 52, 45, 64 to one another (see, for example, Figs. 1, 2, 8, or 12 to 14). Self-regulation in the present case means passive regulation, i.e., without further technical means. However, it is also conceivable to provide an active regulation of the fluid level of the sumps 52, 45, 64 by pumps, in which, for example, a control system can be provided as well as level sensors which detect the level in the sumps 52, 45, 64.

[0084] Preferably, a return line 2, which is also referred to in particular as a fluid line channel 15, extends for conducting fluid from the condenser sump 64 into the container 45 or the intercooling sump 44. Furthermore, preferably, a fluid line channel 15 for conducting fluid from the container 45 or the intercooling sump 44 extends from the container 45 or the intercooling sump 44 into the evaporator sump 52, wherein in particular the fluid line channel 15 extends from a bottom of the container 45 or the intercooling sump 44 laterally into the evaporator sump 52 below the fluid level 51 of the evaporator sump 52. Preferably, the container 45 is an intercooling sump 44 of an intercooler 40.

[0085] Preferably, the heat pump 100 has an intercooling circulation pump 22 to

[0086] To supply intercooling fluid from the tank 45 to the pipe 56. In this embodiment of the heat pump 100, the intercooling fluid supply line 3 can extend from the tank 45 to the pipe 56 (see Fig. 8). In the embodiments of Figs. 12, 13, and 14, the intercooling circulation pump 22 can supply intercooling fluid from the evaporator sump 52 to the pipe 56.

[0087] Fig. 9 shows a hydraulic diagram of the indirect intercooler 8 with indirect heat exchanger 82. In a simplified representation, Fig. 9 shows that the steam channel 30 extends from the upper evaporator part 54, in which in particular the first compressor of the first compressor stage 10 is arranged and in which the heat exchanger 82 can be arranged, to the second compressor stage 20. Compressed fluid emerging from the first compressor stage 10 can therefore be guided via the steam channel 30 to the second compressor stage 20. Furthermore, starting from the arranged heat exchanger 82, one of the fluid line channels 15 extends, in which the fluid flowing through the heat exchanger 82 can be guided into the container 45. The legend in Fig. 9 further shows that the fluid line channels 15 and the intercooler fluid supply line 3 conduct liquid fluid, ie in this case water.Furthermore, it can be seen that the vapor channel 30 between the first and second compressor stages 10, 20 is an active vapor path. Active vapor path in this case means that the second compressor stage 20 is in operation, so that compressed fluid leaving the first compressor stage is sucked in by the second compressor stage 20. The bypass channel 62 between the first compressor stage and the condenser 60, on the other hand, is an inactive vapor path. In this case, inactive vapor path means that the second compressor stage 20 is out of operation and the cross-section reduction element 70 is open, so that compressed fluid leaving the first compressor stage is guided directly into the condenser 60 via the bypass channel 62.

[0088] According to a further preferred embodiment, the heat pump 100 comprises the evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has the evaporator sump 52. Furthermore, the heat pump 100 comprises the compressor with the first compressor stage 10 and the second compressor stage 20. The compressor is arranged between the evaporator 50 and the condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain compressed fluid. The condenser 60 serves to condense the compressed fluid.In addition, the heat pump 100 comprises the intercooler 40, which is connected to an intercooling fluid supply line 3 and has the effect element 42, wherein the effect element is arranged between the first compressor stage 10 and the second compressor stage 20 and is designed to bring about an interaction between an intercooling fluid that can be supplied through the intercooling fluid supply line 3 and a heated vaporous fluid that can be output from the first compressor stage 10. The intercooling fluid supply line 3 extends from the evaporator sump 52 to the effect element 42. Such a preferred embodiment of the heat pump is shown as a hydraulic diagram, for example, in Fig. 12. Fig. 12 further shows the hydraulic diagram from which a feed of the intercooling emerges, wherein the intercooling is fed from the evaporator sump 52.Fluid from the evaporator sump 52 is supplied to the effector element 42 via the intercooling fluid supply line 3, so that the fluid from the evaporator sump 52 can be used to sprinkle evaporated and compressed fluid passing through the intercooler 40 arranged in the steam channel 30.

[0089] Preferably, the intercooling fluid supply line 3 extends through an opening in the evaporator sump 52, and wherein the opening of the intercooling fluid supply line 3 lies below a fluid level 51 of the fluid in the evaporator sump 52. The fluid from the evaporator sump 52 can flow, in particular by utilizing gravity, into the intercooling fluid supply line 3. In particular, the intercooling fluid supply line 3 does not require a controller for supplying fluid from the evaporator sump 52. However, it is conceivable to provide a controller for supplying liquid fluid to the intercooling fluid supply line 3.

[0090] As shown in Fig. 12, the intercooler 40 preferably has an intercooling sump 44, wherein a return line 2 or a fluid conduit 15 for returning fluid from the intercooling sump 44 into the evaporator sump 52 extends from a bottom of the intercooling sump, preferably laterally, into the evaporator sump 52. In particular, the heated vaporous fluid discharged by the first compressor stage 10 and the intercooling fluid are each taken from the evaporator sump 52.

[0091] Preferably, a further return line 1, which can also be referred to in particular as a fluid line channel 15, for returning fluid from the condenser sump 64 to the evaporator sump 52, extends from the condenser sump 64 directly, preferably laterally, into the evaporator sump 52. In particular, the return line 2 and the further return line 1 are fluidically separated from one another. "Fluidically separated from one another" means that the fluid from the return line 2 and the further return line 1 cannot mix in one line, but are only mixed with one another in the evaporator sump 52. With regard to lines 1, 2 and 3, Figs. 12 and 14 show an identical arrangement of the lines 1, 2, 3.

[0092] Fig. 14 shows a further preferred embodiment of the heat pump 100, as shown in Fig. 12. Fig. 14 shows a hydraulic diagram as in Fig. 12, from which a feed of the intermediate cooling emerges, with additional filler bodies 7 and / or additional further intermediate cooling systems 4, 5, wherein each intermediate cooling system 4, 5 is fed from the evaporator sump 52.

[0093] According to the further preferred embodiment of the heat pump, as shown in Fig. 14, the intercooling fluid supply line 3 is connected to at least one further intercooler 4, 5. The further intercooler 5 can be arranged in the steam channel 30 between the evaporator 50 and the condenser 60. The further or yet further intercooler 4, 5 can be arranged in particular downstream of an outlet of the first compressor stage 10.

[0094] As shown in the embodiments according to Fig. 12 and 14, the intercooling sump 44 is designed to collect fluid that can flow through the intercooling fluid supply line 3, wherein the fluid can be supplied from the intercooling sump 44 to the evaporator sump 52 via the return line 2, or also called fluid line channel 15. In particular, the return line 2 and the further return line 1 each have an opening 55 to the evaporator sump 52 at spaced-apart positions of the evaporator sump 52. In particular, the opening 55 of the further return line 1 into the evaporator sump 52 is arranged below a fluid level 51 of the evaporator sump 52. Furthermore, in particular, the opening 55 of the return line into the evaporator sump 52 is arranged below a fluid level 51 of the evaporator sump 52.

[0095] Preferably, the intercooling fluid supply line 3 or an engine cooling line 33 is arranged from the evaporator sump 52 to an engine cooling system 34 of the first compressor stage 10 in order to conduct fluid from the evaporator sump 52 to the engine cooling system 34 for cooling an engine M assigned to the first compressor stage 10. In particular, the intercooling fluid supply line 3 and / or the engine cooling line 33 extend from the evaporator sump 52 via the engine cooling system 34 of the first compressor stage 10 to the effect element 42 in order to conduct fluid from the evaporator sump 52 to the engine cooling system 34 for cooling an engine M assigned to the first compressor stage 10 and to the effect element 42 (see Figs. 12 and 14).

[0096] As can also be seen from Figs. 12 and 14, a further engine cooling line 35 is arranged from the evaporator sump 52 to a further engine cooling system 36 of the second compressor stage 20, in order to conduct fluid from the evaporator sump 52 to the further engine cooling system 36 for cooling a motor M assigned to the second compressor stage 20. The motors M assigned to the compressor stages 20, 30, 80 can be cooled with fluid from the evaporator sump 52. The fluid from the evaporator sump 52 is cooler than the fluid from an intercooling sump 44. The fluid from one of the intercooling sumps 44 is, in turn, cooler than the fluid from the condenser sump 64.

[0097] As can be seen, for example, from Figs. 1, 2, 8 or 12 to 15, a ball bearing adapter line 74 is preferably arranged from the intercooling sump 44 to a ball bearing adapter 76, which is assigned to the first compressor stage 10, in order to conduct fluid from the intercooling sump 44 for cooling the at least one ball bearing adapter 76. In particular, a compressor cooling channel 77 is arranged from an outlet of the ball bearing adapter 76 to the first compressor stage 10 in order to conduct fluid from the ball bearing adapter 76 to the first compressor stage 10 in order to spray compressed fluid in the first compressor stage 10 with the fluid from the ball bearing adapter 76.

[0098] Furthermore, a ball bearing adapter line 74 is preferably arranged from the condenser sump 64 to a ball bearing adapter 76, which is assigned to the second compressor stage 20, in order to conduct fluid from the condenser sump 64 for cooling the at least one ball bearing adapter 76. In particular, a compressor cooling channel 77 is arranged from an outlet of the ball bearing adapter 76 to the second compressor stage 20 in order to conduct fluid from this ball bearing adapter 76 to the second compressor stage 20 in order to spray compressed fluid in the second compressor stage 20 with the fluid from the ball bearing adapter 76, which is assigned to the second compressor stage 20. In an embodiment not shown, the ball bearing adapter can also receive fluid for cooling from the intermediate cooling fluid supply line 3 and thus be connected in series or parallel to the same line to which the engine cooling system 36 is connected.

[0099] Preferably, at least one filler body 7 is arranged in an area around the first compressor stage 10 to dissipate heat, in particular to increase the surface area and thus for optimized cooling of the steam. The at least one filler body 7 is arranged in particular around the intake port 12 of the first compressor stage 10 (cf. Fig. 14). In a particularly advantageous embodiment, the at least one filler body comprises numerous individual filler bodies distributed around the intake port 12 of the first compressor stage 10.

[0100] As can be seen from Fig. 14, for example, a yet further intercooler 4 is preferably arranged in the intercooling fluid supply line 3. In particular, due to the arrangement of the intercooler 40, the further intercooler 4 and the yet further intercooler 5, the vapor, i.e. the evaporated and compressed fluid, in the intercooling fluid supply line 3, after exiting the first compressor stage 10, first passes through the further intercooler 4 and then the yet further intercooler 5 and / or the intercooler 40. It is conceivable for the heat pump 100 to comprise only the further intercooler 4 and the yet further intercooler 5 (see Fig. 14). It is furthermore conceivable for the heat pump 100 to comprise only the intercooler 40 (see Fig. 12). It is furthermore conceivable for the heat pump 100 to comprise only the intercooler 40 and the further intercooler 4 or the yet further intercooler 5.In an embodiment not shown, it is also possible for the intercooler 5 to extend over the entire length of the steam channel 30, thus providing particularly efficient cooling of the steam flowing past.

[0101] Preferably, the further intercooler 4 is designed as a heat exchanger 82, which is designed as a pipe 56 and / or as a tube bundle 56a and has a tube volume through which fluid from the evaporator sump 52 flows in order to enable indirect cooling 8 of the vapor. Figs. 8 to 10, for example, show the indirect cooling 8 by the heat exchanger 82. The heat exchanger 82 has already been discussed in detail, to which reference is made at this point. Preferably, the second compressor stage 20 is arranged between the evaporator 50 and the condenser 60, and the intercooler 40, the further intercooler 4 and / or the yet further intercooler 5 are arranged at a distance from an intake region of the second compressor stage 20. As shown, for example, in Fig.14, the intercooler 40 and / or the further intercooler 4 and / or the still further intercooler 5 can be arranged in the upper evaporator part 54 and / or starting from the first compressor stage 10 in the steam channel 30 up to the sink 32.

[0102] To regulate a fluid fill level, i.e. a fluid level 51, the condenser sump 64 and / or the evaporator sump 52 and / or the intercooling sump 44 can each have a level control. Level control can preferably be dispensed with if the fluid level 51 in the individual sumps 52, 44, 64 controls itself via the height of the outflows, i.e. if self-regulation, as already described, is possible. Then the fluid level 51 does not need to be actively regulated. In the present case, outflows mean, for example, the opening 65 of the steam guide line 92 into the condenser 60, and / or the opening 65 of the return line 2 into the intercooling sump 44 and / or the opening 65 of the intercooling fluid supply line 3 into the evaporator sump 52, as shown, for example, in Figs. 12, 13 and 14.

[0103] As already explained, Fig. 15 shows a compressor map 170 of an N-stage compressor, wherein the compressor map 170 defines a relationship between a pressure ratio and a mass flow.

[0104] Fig. 16 shows a three-dimensional envelope surface 180 over a corrected mass flow, with the dotted lines representing measured speed characteristics 181. The speed characteristics 181 depend on the corrected mass flow WCcorr and the compression ratio PiC. Similar to Fig. 15, the surge limit 171 is plotted in Fig. 16 as a function of the corrected mass flow and the compression ratio. The envelope surface 180 is shown as a compensation surface (3D fit) which has been adapted to the measured speed characteristics 181. The envelope surface 180 initially increases with increasing corrected mass flow and increasing speed and is represented by a three-dimensional monotonically increasing function. After reaching a mass flow of approximately 0.8, the envelope surface 180 branches off a monotonically decreasing curve. Fig. 17 shows a three-dimensional representation for determining a volume flow to determine the corrected mass flow.The volume flow is given by a function which depends on the electrical power P. ei and the speed of compressor stages 10 and 20. Preferably, compressor stages 10 and 20, which are identical in design, are used for heat pumps 100. It is conceivable to use compressor stages 10 and 20 that are different from each other.

[0105] The volume flow cannot be measured directly. Instead, it is determined indirectly via a stored 3D characteristic map 190, which is specific to the compressor drive used. The volume flow is determined as a function of the consumed electrical power P eiand the speed of the compressor drive using the 3D characteristic map in the 3D characteristic map 190 (see dotted curves 191), in which the measured values ​​191 are entered in the 3D characteristic map 190. After determining the volume flow, the mass flow can be corrected, in particular by applying the knowledge of the molar mass of the fluid at a given pressure and a given temperature.

[0106] According to a preferred embodiment, the heat pump 100 comprises the evaporator 50 for evaporating a fluid to obtain an evaporated fluid; the condenser 60 for condensing a compressed fluid; and the compressor with a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged between the evaporator 50 and the condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain the compressed fluid.In addition, the heat pump 100 comprises a value detection device 95 for detecting a first value P1, which corresponds to a first pressure ratio between an inlet of the first compressor stage 10 and an outlet of the first compressor stage 10 or is dependent on the first pressure ratio; and a controller 96 for controlling a first speed of the first compressor stage 10 and a second speed of the second compressor stage 20, wherein the controller 96 is designed to control the second speed of the second compressor stage 20 as a function of the first value P1. The value detection device 95 and the controller 96 can communicate with each other and can each communicate with components of the heat pump 100, as indicated in Fig. 18 by the arrows in opposite directions.The outlet of the first compressor stage 10 comprises a region immediately after the first compressor stage 10 as well as a region between the first compressor stage 10 and the second compressor stage 20, in particular a region in the steam channel 30.

[0107] Preferably, the value detection device 95 is designed to detect a second value P2, which corresponds to a second pressure ratio between an outlet of the second compressor stage 20 and an inlet of the first compressor stage 10 or is dependent on the second pressure ratio, and wherein the controller 96 is designed to further control the second rotational speed as a function of the second value P2. In particular, a region of the inlet of the second compressor stage 20 can adjoin the region of the outlet of the first compressor stage 10. For example, the region of the outlet of the first compressor stage 10 can end in the depression 32 and the region of the inlet of the second compressor stage 20 can begin in the depression 32 of the steam channel 30 (see Fig. 18).

[0108] Fig. 18 shows the hydraulic diagram of the heat pump 100, in which the first temperature sensor 91, the second temperature sensor 92 and the third temperature sensor 93 are shown. Fig. 18 also shows the controller 96 and the value acquisition device 95, which each communicate with the individual components of the heat pump 100 and with each other. The cooling liquid 97 indicates the cold water temperature that a user of the heat pump 100 receives as the actual temperature. The first temperature sensor 91 measures the first temperature TU in the evaporator sump 52 and thus before the first compressor stage 10. The second temperature sensor 92 measures the second temperature TI3 in the intercooling sump 44 and thus after the first compressor stage 10 and before the second compressor stage 20. The third temperature sensor 93 measures the third temperature TI2 in the condenser sump 64 and thus after the second compressor stage. As Fig.18 suggests, the user is provided with a cooling capacity 103, which serves as power for cooling customer water. This is power that is provided to the user or customer. The dissipated heat output 105 is heat output that is dissipated via a dry cooler. The motors M of the compressor stages 10, 20 absorb the electrical power 104, which is the absorbed power of the heat pump 100, which is absorbed via the two compressor stages 10, 20. For example, a maximum pressure ratio of the first compressor stage 10 can be P1 = 3.7. For example, a maximum pressure ratio of the second compressor stage 20 can be P2 = 3.7. In this case, for example, the maximum total pressure ratio P gesof the heat pump 100 Ptotal=P1 * P2 =3.7 *3.7 =13.7. In conjunction with Fig. 19, it can further be summarized that in case 1, the first compressor stage 10 is operated constantly at a pressure ratio of, for example, P1 =2.7 and the second compressor stage 20 is operated at a pressure ratio P2 between zero and 2.7. If the first compressor stage 10 and the second compressor stage 20 are each operated at a pressure ratio of P1 =P2=2.7, the heat pump 100 switches from case (first power range 98) to case 2 (second power range 99). In the second power range 99, the compression ratios of the first compressor stage 10 and the second compressor stage 20 each increase evenly from P1 =P2=2.7 to P1 =P2=3.7.

[0109] Preferably, the controller 96 is designed to use the first value P1 as the actual value and the second value P2 as the setpoint. Furthermore, the controller 96 is preferably designed to increase the speed of the second compressor stage 20 if the actual value is greater than the setpoint, or to decrease the speed of the second compressor stage 20 if the actual value is less than the setpoint. By comparing the actual value with the setpoint, the speeds of the first and second compressor stages 10, 20 can each be set such that the second compressor stage can be used efficiently independently of the first compressor stage 10. Independent adjustment of the speeds of the first and second compressor stages 10, 20 is achieved in that each motor M of the compressor stages 10, 20 has its own motor shaft to be driven. The first value P1 indicates a compression ratio of the first compressor stage 10 according to P1 = TI3 / TI1.The second value P2 indicates a compression ratio of the second compressor stage 20 according to P2=TI2 / TI3.

[0110] Preferably, the value detection device 95 is further designed to determine an actual temperature of a cooling liquid 97 discharged on the evaporator side, and in which the controller 96 is designed to adjust the speed of the first compressor stage 10 depending on the actual temperature of the cooling liquid 97 and a predefined target temperature of the cooling liquid 97. During operation of the heat pump 100, it can increase the actual temperature of the cooling liquid 97 discharged on the evaporator side, since the operation of the heat pump 100 causes the fluid circulating in the heat pump, i.e. the cooling liquid 97, to assume a higher temperature over time.

[0111] Preferably, the control is designed to be dependent on a

[0112] Power requirement in a first power range 98 to operate the first compressor stage 10 with a higher pressure ratio than the second compressor stage 20, wherein a difference in the pressure ratios of the first compressor stage 10 and the second compressor stage 20 decreases as the power requirements increase (see case 1 in Fig. 19), and in a second power range 99 to operate both the first compressor stage 10 and the second compressor stage 20 such that pressure ratios of the two compressor stages 10, 20 in the second power range 99 are approximately the same, or in particular the same within a range of plus / minus 20 percent, and / or increase equally as the power requirement increases (see case 2 in Fig.19), wherein the second power range 99 comprises greater power requirements than the first power range 98, wherein a boundary 94 between the first power range 98 and the second power range 99 is defined by the first compressor stage 10 and / or by the second compressor stage 20. Fig. 19 shows a diagram illustrating a control of the compressor stages 10, 20 of the heat pump 100 as a function of the speeds of the first and second compression stages 10, 20 in the first power range 98 and in the second power range 99. In case 2, i.e. the second power range 99, a higher power TT is implemented than in the first case, i.e. in the first power range 98 (cf. Fig. 19). It can also be seen from Fig. 19 that the first compressor stage 10 operates at a constant power value, in particular TT=2.7.The constant power value TT of the first compressor stage 10 corresponds to a setpoint in the first line range 98 at which the first compressor stage is to be operated. The second compressor stage 20 starts with an initially lower power TT, but increasingly approaches the setpoint of the first power stage 10. When the second compressor stage 20 also reaches the setpoint power TT, both compressor stages 10, 20 switch over to an operation which corresponds to case two, i.e., the second power range 99. In the second power range, the pressure ratio of the first compressor stage 10 and the second compressor stage 20 preferably increases evenly. At the boundary 94, operation changes from the first power range 98 to the second power range 99.

[0113] 1 / ? switched. In particular, at a total pressure ratio of p(Tl2) / p(Tll)), the heat pump 100 switches from operation in the first power range 98 to operation in the second power range 99, where p(Tll) indicates a saturated vapor pressure in the evaporator sump 52, which is measurable in particular by the first temperature sensor 91, and where p(Tl2') indicates a saturated vapor pressure in the condenser sump 64, which is measurable in particular by the third temperature sensor 93 (cf. Fig. 18).Preferably, the first compressor stage 10 and the second compressor stage 20 have radial impellers of different sizes, wherein the controller 96 is designed to control the first compressor stage 10 in the first power range 98 to a constant first pressure ratio as the setpoint, and to control the second compressor stage 20 with increasing power demand to an increasing second pressure ratio as the setpoint, and to accommodate an increasing power demand in the second power range 99 by both the first compressor stage 10 and the second compressor stage 20 (cf. Fig. 19). For example, the setpoint for the compressor stages 10, 20 used is 2.7, as already explained. When using other compressor stages, the setpoint can be different. In particular, the setpoint is compressor-specific.Preferably, the radial impeller of the first compressor stage 10 is larger than the radial impeller of the second compressor stage 20. Both radial impellers are designed in particular to pass approximately the same mass flow. Since the temperature upstream of the second radial impeller, i.e., the radial impeller of the second compressor stage 20, is higher than upstream of the first radial impeller, i.e., the radial impeller of the first compressor stage 10, the second radial impeller must be smaller.

[0114] Preferably, the controller 96 is configured to use a maximum value from a function of the second value P2 or a predefined constant const as the setpoint for controlling the second speed of the second compressor stage 20. The predefined constant depends on the compressors used and is preferably in the range between 1 and 5, i.e., 1 < const. <5, more preferably in the range between 2 and 4, with the constant const=2.7 being particularly advantageous. The constant is the optimal pressure ratio of the first compressor. The maximum value of the second speed of the second compressor stage 20 is therefore given by:

[0115] Maximum value = P2 or const.

[0116] The maximum value is given by a maximum function which takes the highest value from the second value P2 or a predefined constant const.

[0117] Preferably, the maximum function is a root function and the predefined constant is the boundary 94 between the first and second power ranges 98, 99. The maximum function is given in particular by ( (n2) / (ni)) 1 / 2 , where jo(ni) indicates a saturated vapor pressure in the evaporator sump (52), which is measurable in particular by the first temperature sensor 91, and where p(Tl2) indicates a saturated vapor pressure in the condenser sump 64, which is measurable in particular by the third temperature sensor 93 (cf. Fig. 18).

[0118] The first value P1 is given by the ratio: P1 =TI3 / T11 .

[0119] The second value P2 is given by the ratio: P2 =TI2 / TI3.

[0120] A total compression ratio P ges , as shown in Fig. 19, is given by the product of the first value P1 and the second value P2, namely:

[0121] P ges=P1*P2= (TI3 / TI1 ) * (TI2 / TI3) = TI2 / TI1

[0122] As can be seen, for example, from Fig. 19, the first value P1 and the second value P2 are added geometrically (hence 2* a / 2= a) to obtain the total compression ratio Ptotal.

[0123] Preferably, the value detection device 95 comprises a first temperature sensor for detecting a first temperature TU with respect to the evaporator 50, and a second temperature sensor for detecting a second temperature TI3 with respect to an output of the first compressor stage 10, wherein the value detection device 95 is designed to determine the first value P1 from the first temperature TU and the second temperature TI3. ​​For example, Fig. 18 shows where the temperature sensors could be arranged in the hydraulic diagram of the heat pump 100, indicating where each of the temperatures TH, TI2, and TI3 ​​can be measured.

[0124] Preferably, the first temperature sensor is arranged in the evaporator sump 52 of the evaporator 50 in order to detect the first temperature TU upstream of the first compressor stage 10, and the second temperature sensor is arranged in an intercooling sump 44 in order to detect the second temperature TI3 downstream of an outlet of the first compressor 10. Preferably, the outlet of the first compressor 10 comprises the sink 32 in the vapor channel 30, which fluidically connects the first compressor stage 10 and the second compressor stage 20. Preferably, the vapor channel 30 is provided between the first compressor stage 10 and the second compressor stage 20 in order to guide compressed fluid from the first compressor stage 10 into the second compressor stage 20, wherein the intercooling sump 44 or the container 45 is arranged in the vapor channel 30. The first compressor stage 10 and the second compressor stage 20 are fluidically connected to one another by the vapor channel 30.

[0125] As can be seen from Fig. 18, the value detection device 95 comprises a third temperature sensor for measuring a third temperature TI2, wherein the value detection device 95 is designed to determine the second value P2 from the third temperature TI2 and the first temperature (TU). Preferably, the third temperature sensor is arranged in the condenser sump 64 in order to detect the third temperature TI2 after the second compressor stage 20. Fig. 18 shows a hydraulic diagram highlighting temperature sensors for controlling the second compressor, in particular where the temperature sensors could be arranged in the heat pump 100 in order to measure the respective temperature TU, TI2 or TI3. ​​As shown, for example, in Fig.8 shows, the second temperature sensor can also be arranged in the container 45 instead of in the intercooling sump 44, i.e. in a sump 44, 45 which fluidically connects the first compressor stage 10 and the second compressor stage.

[0126] Preferably extends from the condenser sump 64 into the intercooling sump

[0127] 44 (Fig. 18) or into the container 45 (Fig. 8) a fluid line channel 15 extends to convey fluid from the condenser sump 64 into the intermediate cooling sump 44 or into the container

[0128] 45, and wherein a further fluid line channel 15 extends from the intercooling sump 44 or the container 45 in the evaporator sump 52 in order to conduct fluid from the intercooling sump 44 or the container 45 into the evaporator sump 52. By connecting the sumps 64, 44, 45 and 52 to one another via the fluid lines 15, the fluid in each of the sumps 64, 44, 45 and 52 is increased during the operation of the heat pump 100. As a result, due to the running time of the heat pump 100 alone, it may be necessary to regulate the compressor stages of the heat pump, as shown in Fig. 19.

[0129] Preferably, a bypass channel 62 is arranged between the first compressor stage 10 and the condenser 60 to bypass the second compressor stage 20. A cross-section reduction element 70 is arranged in the bypass channel 62 to adjust a cross-section of the bypass channel 62 in order to regulate a flow of compressed fluid from the first compressor stage 10 to the condenser 60. The cross-section reduction element 70 assumes a closed position during operation of the second compressor stage 20. The bypass channel 62 and the cross-section reduction element 70 have already been described in detail, to which reference is made.

[0130] The speeds of the compressor stages 10, 20 can be increased for two reasons, since both the user side and the dry cooler side act on the heat pump. For example, the cold water temperature 97 may rise. The water used by the user, which is provided to them, simply has a higher temperature, i.e. the user requires more cooling capacity. In this case, the speed of the first compressor stage 10 is increased, whereby more electrical power 104 is supplied to the heat pump 100. This increases the cooling capacity 103 generated by the heat pump. In another case, the cold water temperature 97 may rise if the water temperature from the dry cooler to the condenser rises, for example if the outside temperature rises and the dry cooler can only dissipate the heat energy with greater energy expenditure.In this case, for example, the measured temperatures TU, TI3, and TI2 rise, ultimately increasing the cold water temperature supplied to the user. For the operation of compressor stages 10 and 20, this means that the speed of the first compressor stage is initially increased, and then, after a second delay, the speed of the second compressor stage is also increased. As the cooling water temperature rises, the electrical power consumption 104 of the heat pump 100 also increases.

[0131] The heat pump described here allows the second compressor to be used more efficiently, which in turn allows the heat pump itself to be used more efficiently. It also prevents the second compressor stage from operating at the surge limit or the absorption limit.

[0132] Specifically, the first compressor stage provides the user with the requested cooling capacity. The second compressor stage 20 transfers the heat from the heat pump 100 to the dry cooler. If the first compressor stage 10 provides the user with more cooling capacity, the additional heat output is transferred to the dry cooler by the compressor stage 20, thereby increasing the electrical power consumed by the heat pump.

[0133] A further aspect relates to a method for operating a heat pump 100 with an evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has an evaporator sump 52; a condenser 60 for condensing evaporated fluid compressed by an N-stage compressor, wherein the condenser 60 has a condenser sump 64, a condensation region 66 and a holding region 67 for holding a vaporous fluid still remaining after the condensation region 66; the N-stage compressor, which comprises N compressors, where N is a natural number greater than or equal to one, wherein the N-stage compressor is arranged between the evaporator 50 and the condenser 60;a vapor channel 30 coupling at least two of the N compressors of the N-stage compressor between the evaporator 50 and the condenser 60, and a vapor guide line 92 arranged between the condenser 60 and the evaporator 50 to guide vaporous fluid from the holding area 67 of the condenser 60 into the evaporator 50, comprising the following steps:;

[0134] Evaporating fluid through the evaporator 50;

[0135] Feeding the evaporated fluid into the first compression stage 10 to compress the evaporated fluid,

[0136] Passing the compressed fluid through the vapor channel 30 to pass the N compressors; to finally reach the condenser 60;

[0137] Condensing the compressed fluid in the condensation region 66 and holding uncondensed fluid in the holding region 67; and returning the evaporated fluid from the holding region 67 to the evaporator 50 via the vapor guide line 92.

[0138] A further aspect relates to a method for manufacturing a heat pump 100 with an evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has an evaporator sump 52; a condenser 60 for condensing evaporated fluid compressed by an N-stage compressor, wherein the condenser 60 has a condenser sump 64, a condensation region 66, and a holding region 67 for holding a vaporous fluid still remaining after the condensation region 66; the N-stage compressor, which comprises N compressors, where N is a natural number greater than or equal to one, wherein the N-stage compressor is arranged between the evaporator 50 and the condenser 60;a vapor channel 30 coupling at least two of the N compressors of the N-stage compressor between the evaporator 50 and the condenser 60, and a vapor guide line 92 arranged between the condenser 60 and the evaporator 50 to guide vaporous fluid from the holding area 67 of the condenser 60 into the evaporator 50, comprising the following steps:;

[0139] Arranging the evaporator 50, the N-stage compressor and the condenser 60; connecting the evaporator, the N-stage compressor and the condenser 60 via the steam channel 30; and

[0140] Connecting the evaporator and the condenser 60 via the vapor guide line 92 to create a circuit in which the fluid circulates.

[0141] A further aspect relates to a method for operating a heat pump 100 having an evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has an evaporator sump 52; a condenser 60 for condensing a compressed fluid, wherein the condenser 60 has a condenser sump 64; a compressor having a first compressor stage

[0142] 10 and a second compressor stage 20, wherein the compressor is arranged between the evaporator 50 and the condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain the compressed fluid; the method comprising the steps:

[0143] Collecting an intermediate cooling fluid in a container 45; and

[0144] Flowing through a heat exchanger 82 with a pipe 56 with the intermediate cooling fluid from the container 45, wherein the pipe 56 is in a flow area

[0145] 11 is arranged between the first compressor stage 10 and the second compressor stage 20 in order to cool vaporous fluid in the flow region 11.

[0146] A further aspect relates to a method for manufacturing a heat pump 100 with an evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has an evaporator sump 52; a condenser 60 for condensing a compressed fluid, wherein the condenser 60 has a condenser sump 64; a compressor with a first compressor stage 10 and a second compressor stage 20, the method comprising: arranging the compressor in the flow direction of the evaporated fluid such that during operation of the heat pump 100 the compressor is arranged between the evaporator 50 and the condenser 60 to compress the evaporated fluid to obtain the compressed fluid;

[0147] Arranging a container 45 for collecting an intermediate cooling fluid; and arranging a heat exchanger 82 with a pipe 56 in a flow region 11 between the first compressor stage 10 and the second compressor stage 20, in order to allow the intermediate cooling fluid from the container 45 to flow through the pipe 56 during operation of the heat pump and to cool vaporous fluid in the flow region 11

[0148] A further aspect relates to a method for operating a heat pump 100 with an evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has an evaporator sump 52; a compressor with a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged between the evaporator 50 and a condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain compressed fluid; and the condenser 60 for condensing the compressed fluid; and an intercooler 40, which is connected to an intercooling fluid supply line 3 and which has an effect element 42, wherein the effect element 42 is arranged between the first compressor stage 10 and the second compressor stage 20, the method comprising:

[0149] Supplying intercooling fluid via the intercooling fluid supply line 3 from the evaporator sump 52 into the effect element 42;

[0150] Discharge of a heated vaporous fluid by the first compressor stage 10; Interacting the intercooling fluid, which can be supplied through the intercooling fluid supply line 3, with the heated vaporous fluid discharged from the first compressor stage 10 to cool the vaporous fluid.

[0151] A further aspect relates to a method for manufacturing a heat pump 100 with an evaporator 50 for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator 50 has an evaporator sump 52; a compressor with a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged between the evaporator 50 and a condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain compressed fluid; and the condenser 60 for condensing the compressed fluid; wherein the method comprises:

[0152] Arranging an intercooler 40 with an effect element 42 between the first compressor stage 10 and the second compressor stage 20

[0153] Connecting the intercooler 40 to an intercooling fluid supply line 3 extending from the evaporator sump 52 to the effector 42 in order to effect, during operation of the heat pump 100, an interaction between an intercooling fluid which can be supplied through the intercooling fluid supply line 3 and a heated vaporous fluid which can be discharged from the first compressor stage 10.

[0154] A further aspect relates to a method for operating a heat pump 100 having an evaporator 50 for evaporating a fluid to obtain evaporated fluid; a condenser 60 for condensing a compressed fluid; a compressor having a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged between the evaporator 50 and the condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain compressed fluid; and a bridging channel 62 between the first compressor stage 10 and the condenser 60, the method comprising:

[0155] Bridging the second compressor stage 20 by adjusting a cross-section of a cross-section reducing element 70 in the bridging channel 62 to regulate a flow of compressed fluid from the first compressor stage 10 to the condenser 60.

[0156] A further aspect relates to a method for producing a heat pump 100 with an evaporator 50 for evaporating a fluid to obtain evaporated fluid; a condenser 60 for condensing a compressed fluid; a compressor with a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged between the evaporator 50 and the condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain compressed fluid; wherein the method comprises

[0157] Arranging a bridging channel 62 between the first compressor stage 10 and the condenser 60 to bridge the second compressor stage 20,

[0158] Arranging a cross-section reducing element 70 in the bypass channel 62 to adjust a cross-section of the bypass channel 62 to regulate a flow of compressed fluid from the first compressor stage 10 to the condenser 60.

[0159] A further aspect relates to a method for operating a heat pump 100 having an evaporator 50 for evaporating a fluid to obtain an evaporated fluid; a condenser 60 for condensing a compressed fluid; and a compressor having a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged between the evaporator 50 and the condenser 60 in the flow direction of the evaporated fluid during operation of the heat pump 100 and is designed to compress the evaporated fluid to obtain the compressed fluid, comprising the following steps:

[0160] Detecting a first value P1 which corresponds to a first pressure ratio between an inlet of the first compressor stage and an outlet of the first compressor stage or is dependent on the first pressure ratio; and controlling a first speed of the first compressor stage 10 and a second speed of the second compressor stage 20, wherein the second speed of the second compressor stage 20 is controlled as a function of the first value P1.

[0161] Another aspect relates to a method for manufacturing a heat pump 100 comprising: an evaporator 50 for evaporating a fluid to obtain an evaporated fluid; a condenser 60 for condensing a compressed fluid; and a compressor having a first compressor stage 10 and a second compressor stage 20, comprising the following steps:

[0162] Arranging the compressor in the flow direction of the evaporated fluid during operation of the heat pump 100 between the evaporator 50 and the condenser 60 in order to compress the evaporated fluid to obtain the compressed fluid; and connecting a value detection device for detecting a first value that corresponds to a first pressure ratio between an inlet of the first compressor stage and an outlet of the first compressor stage or is dependent on the first pressure ratio to the compressor, the evaporator, or the condenser; and connecting a controller for controlling a first speed of the first compressor stage 10 and a second speed of the second compressor stage 20 to the compressor, wherein the second speed of the second compressor stage 20 is controlled as a function of the first value.

[0163] As already mentioned in the general part, individual aspects described with regard to the heat pump can also be implemented as a process step.

[0164] Preferably, a method for manufacturing a heat pump 100, as described above, can be provided by producing the individual features and combining the individual features to form a heat pump 100 as described above. The individual features will not be discussed again here in connection with the heat pump manufacturing method. Rather, reference is made here to the above description of the individual features, which can also be understood as a manufacturing step.

[0165] Further preferably, a method for operating a heat pump 100 first comprises providing a heat pump 100 as described above.

[0166] To operate the heat pump, at least one, in particular the first, compressor stage 10 is operated. During operation of the first compressor stage 10, fluid is evaporated via the evaporator 50 and thus supplied to the first compressor stage. At the same time, liquid fluid is supplied via the intermediate cooling fluid supply line 3 to an action element 42 and / or a heat exchanger 82. Evaporated and compressed fluid leaving the first compressor stage 10 is cooled as already described above. Furthermore, the method for operating a heat pump 100 comprises adjusting the cross-section reduction element 70 to an open, closed, or intermediate position, as already described above.Depending on the position of the cross-section reduction element 70, the evaporated and compressed fluid leaving the first compressor stage 10 is either conducted through the bypass channel 62 directly to the condenser 60 (inactive vapor path) and / or via the vapor channel 30 to the second compressor stage 20 (active vapor path). With an intermediate position of the cross-section reduction element 70, the inactive and active vapor paths, in particular, can be used to conduct the evaporated and compressed fluid. A description of the circulation of the fluid is already apparent from the above description, which will not be repeated in connection with the method for operating the heat pump to avoid redundancies. Rather, reference is also made here to the above description, which can also be understood as method steps for operating the heat pump.

[0167] In particular, the various features described can be combined or interchanged as desired. In particular, fluid and cooling water are used synonymously. In particular, the term "steam" refers to vaporized fluid.

[0168] List of reference symbols

[0169] 1 additional return line

[0170] 3 Intermediate cooling fluid supply line

[0171] 2 return line

[0172] 4 additional intercoolers

[0173] 5 additional intercooler

[0174] 7 packing

[0175] 8 indirect intermediate cooling

[0176] 10 first compressor stage

[0177] 11 Flow area

[0178] 12 intake manifolds

[0179] 14 Control room

[0180] 15 Fluid line channel

[0181] 16 maximum diameter

[0182] 17 minimum diameter

[0183] 20 second compressor stage

[0184] 22 Circulation pump

[0185] 30 Steam Channel (Banana)

[0186] 32 depression

[0187] 33 Engine cooling line

[0188] 34 Engine cooling

[0189] 35 additional engine cooling lines

[0190] 36 additional engine cooling

[0191] 40 intercoolers

[0192] 42 Effect element

[0193] 44 Intercooling sump

[0194] 45 containers

[0195] 46 first intercooler line

[0196] 48 second intercooler line

[0197] 49 Ball bearing adapter 50 Evaporator

[0198] 51 Fluid level

[0199] 52 Evaporator sump

[0200] 54 upper evaporator part

[0201] 55 Opening into the evaporator

[0202] 56 pipeline

[0203] 56a tube bundle

[0204] 56b spiral tube arrangement

[0205] 57 Irrigation area

[0206] 58 Irrigation device

[0207] 59 first evaporator line

[0208] 60 condensers

[0209] 62 Bridging channel

[0210] 64 Condenser sump

[0211] 65 Opening a pipe into a sump

[0212] 66 Condensation area

[0213] 67 Holding area

[0214] 68 Fill level

[0215] 70 Cross-section reduction element

[0216] 72 Diameter of the cross-section reducing element

[0217] 74 Ball bearing adapter cable

[0218] 76 ball bearing adapters

[0219] 77 Compressor cooling duct

[0220] 80 Nth compressor stage

[0221] 82 heat exchangers

[0222] 83 turns

[0223] 90 Steam transfer flap / bridging flap

[0224] 92 Steam pipe

[0225] 91 first temperature sensor

[0226] 92 second temperature sensor 93 third temperature sensor

[0227] 94 border

[0228] 95 Value recording device

[0229] 96 Control

[0230] 97 Actual temperature of a coolant discharged from the evaporator side

[0231] 98 first management area

[0232] 99 second performance range

[0233] TU first temperature

[0234] TI3 second temperature

[0235] TI2 third temperature

[0236] 100 heat pump

[0237] 101 Helix

[0238] 102 screw axle

[0239] 103 cooling capacity

[0240] 104 electrical power

[0241] 105 dissipated power

[0242] 170 Compressor map / limit lines

[0243] 171 Surge limit

[0244] 172 dotted lines

[0245] 180 envelope area

[0246] 181 Speed ​​characteristic

[0247] P1 first value / actual value

[0248] P2 second value / setpoint

[0249] M engine

[0250] 300 Test bench 301 Compressor to be tested

[0251] 302 pressure sensor

[0252] 303 Temperature sensor

[0253] 304 Steam flow

[0254] 306 pipe

[0255] 307 throttle valve

[0256] 308 Return

[0257] 309 Sensor

[0258] 310 Pump

[0259] 311 connection

[0260] 2' evaporator

[0261] 3' first compressor

[0262] 4' intermediate cooling

[0263] 4a' Intermediate cooling sump

[0264] 4c' pump

[0265] 5' second compressor

[0266] 6' capacitor

[0267] 41 ' containers

[0268] 71 1 supply line

[0269] 72' supply line

[0270] V0 steam bypass

[0271] 50' evaporator

[0272] 60' condenser

Claims

Patent claims 1. Heat pump (100) comprising: an evaporator (50) for evaporating a fluid to obtain an evaporated fluid, the evaporator (50) having an evaporator sump (52); a condenser (60) for condensing a compressed fluid, the condenser (60) having a condenser sump (64); a compressor with a first compressor stage (10) and a second compressor stage (20), the compressor being arranged in the flow direction of the evaporated fluid in operation of the heat pump (100) between the evaporator (50) and the condenser (60) and being configured to compress the evaporated fluid to obtain the compressed fluid; a container (45) for collecting an intercooling fluid;and a heat exchanger (82) with a pipe (56) designed to allow the intercooling fluid from the vessel (45) to flow through it, wherein the pipe (56) is arranged in a flow region (11) between the first compressor stage (10) and the second compressor stage (20) to cool vaporous fluid in the flow region (11).

2. Heat pump (100) according to claim 1, wherein the pipeline (56) is metallic, preferably the pipeline (56) is made of stainless steel or copper.

3. Heat pump (100) according to claim 1 or 2, wherein the pipeline (56) has a region in which the pipeline (56) runs in a spring-like or spiral shape, wherein the spring-like or spiral-shaped region has turns (83) with different turn spacings.

4. Heat pump (100) according to one of claims 1 to 3, wherein the first compressor stage (10) has an intake port (12) for drawing in the evaporated fluid and a guide chamber (14) to direct the vaporous fluid into the flow area (11).

5. Heat pump (100) according to claim 4, wherein the pipe (56) of the heat exchanger (82) is arranged around the intake port (12) of the first compressor stage (10), wherein a winding spacing between two windings (83) in a The inflow area of ​​the vaporous fluid in the first compressor stage (10) is larger than in an outflow area of ​​the vaporous fluid into the guide space (14).

6. Heat pump (100) according to claim 5, wherein a steam channel (30) is arranged between the pipeline (56) and the container (45), wherein the outflow area is connected to the steam channel (30) in order to guide the vaporous fluid through the container (45) via the steam channel (30).

7. Heat pump (100) according to claim 6, wherein a fluid channel (15) extends laterally from the outflow area into the steam channel (30) to supply the intercooling fluid flowing through the heat exchanger (82) to the container (45) via the steam channel (30).

8. Heat pump (100) according to claims 4 to 7, wherein the intake nozzle (12) has a funnel shape which has a maximum diameter (16) and a minimum diameter (17) opposite each other, wherein the guide space (14) for guiding the compressed vaporous fluid extends axially to the minimum diameter (16) of the funnel shape.

9. Heat pump (100) according to one of claims 4 to 8, wherein the guide chamber (14) is curved at one end which transitions into the upper evaporator part (54) in order to direct the vaporous fluid flowing from the guide chamber (14) in a direction opposite to a gas flow direction in the intake nozzle (12), in particular wherein the guide chamber (14) has a volume with a circle or an oval as its base.

10. Heat pump (100) according to one of claims 6 to 9, wherein a further heat exchanger (82) is arranged in the steam channel (30) spaced apart from the outflow area, preferably wherein the further heat exchanger (82) is arranged in an intake port (12) of the second compressor stage (20).

11. Heat pump (100) according to one of claims 6 to 10, wherein the first and the second compressor stage (10, 20) are connected by the steam channel (30), wherein the steam channel (30) is arranged between a pressure side of the first compressor stage (10) and a suction side of the second compressor stage (20), in particular wherein the steam channel (30) has a curved shape with a depression (32), wherein the container (45) is arranged in the depression (32) so that liquid intermediate cooling fluid flows from the vapor channel (30) into the container (45).

12. Heat pump (100) according to one of the preceding claims 1, 5, 7, or 10, wherein the heat exchanger (82) and / or the further heat exchanger (82) has at least a partially contoured outer surface on its outer surface which is in contact with the vaporous fluid in order to improve the heat transfer between the heat transfer medium (82) and the vaporous fluid.

13. Heat pump (100) according to one of the preceding claims 1, 5, 7, or 10, or 12, wherein the heat exchanger (82) and / or the further heat exchanger (82) has at least a partially contoured inner surface on its inner surface which is in contact with the fluid from the container (45) in order to cause the formation of a turbulent flow on its inner surface.

14. Heat pump (100) according to one of the preceding claims, wherein, for the regulation of a fluid level (51), the condenser sump (64), the evaporator sump (52) and the vessel (45) are each fluidly connected to one another via a fluid channel (15) so that the level of the individual sumps (52, 64, 45) is regulated, in particular wherein a first return channel (15) extends from the condenser sump (64) into the vessel (45) for returning fluid from the condenser sump (64), in particular wherein a second return channel (15) extends from the vessel (45) into the evaporator sump (52) for returning fluid from the vessel (45), and / or in particular wherein the second return channel (15) extends laterally from a bottom of the vessel (45) into the evaporator sump (52) below a fluid level (51) of the evaporator sump.

15. Heat pump (100) according to one of the preceding claims, wherein the heat pump (100) has an intercooling circulation pump (22) to supply intercooling fluid from the reservoir (45) to the pipeline (56), in particular wherein the reservoir (45) is an intercooling sump (44) of an intercooler (40).

16. Method for operating a heat pump (100) with an evaporator (50) for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator (50) has an evaporator sump (52); a condenser (60) for Condensing a compressed fluid, wherein the condenser (60) has a condenser sump (64); a compressor with a first compressor stage (10) and a second compressor stage (20), wherein the compressor is arranged in the flow direction of the evaporated fluid in an operation of the heat pump (100) between the evaporator 50 and the condenser (60) and is configured to compress the evaporated fluid to obtain the compressed fluid; wherein the method comprises the steps: Collecting an intercooling fluid in a container (45); and Flowing through a heat exchanger (82) with a pipe (56) with the intercooling fluid from the container (45), wherein the pipe (56) is arranged in a flow region (1 1 ) between the first compressor stage (10) and the second compressor stage (20) to cool vaporous fluid in the flow region (1 1 ).

17. Method for manufacturing a heat pump (100) comprising an evaporator (50) for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator (50) has an evaporator sump (52); a condenser (60) for condensing a compressed fluid, wherein the condenser (60) has a condenser sump (64); a compressor comprising a first compressor stage (10) and a second compressor stage (20), the method comprising: Arranging the compressor in the direction of flow of the evaporated fluid, so that during operation of the heat pump (100) the compressor is arranged between the evaporator (50) and the condenser (60) to compress the evaporated fluid in order to obtain the compressed fluid; Arranging a container (45) for collecting an intercooling fluid; and Arranging a heat exchanger (82) with a pipeline (56) in a flow region (1 1 ) between the first compressor stage (10) and the second compressor stage (20) in order to allow the intercooling fluid from the container (45) to flow through the pipeline (56) during operation of the heat pump and to cool vaporous fluid in the flow region (11 ).

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