HEAT PUMP

Description

[0001] The present invention relates to the field of heat pumps and in particular to concepts for improving the efficiency of a heat pump.

[0002] EP 3 203 164 B describes a heat pump. Fig. 20 This shows the state of the art from EP 3 203 164 B. The heat pump of EP 3 203 164 B is operated with water as the refrigerant. The water is fed from the sump of the condenser 6' through the supply line 71' to the sump of the intercooler. From the sump 4'a of the intercooler 4', the further supply line 72' leads to the sump of the evaporator 2', thus providing a return of the refrigerant to the evaporator. The cooling water is fed by the pump 4'c to the top of the tank 41' of the intercooler for spraying, in order to cool the superheated water vapor leaving the compressor 3'. EP 3 203 164 B discloses direct cooling with direct spraying. In direct spraying, the superheated vapor flowing from the first compressor is cooled down to saturated vapor temperature by spraying it with water from the sump of the intercooler.During this process, droplets can be formed by the spray, which are carried along by the steam towards the second compressor 5' and can damage it due to the impact of the droplets on the impeller. Furthermore, the superheated steam is only cooled in the intercooler. The water collected in the intercooler sump therefore already almost corresponds to the saturated steam temperature. To cool the superheated steam down to the saturated steam temperature level, a relatively large surface area or a long contact time between the water and steam is required. Refrigeration systems are typically limited to a restricted range of cooling capacity. To be able to respond simultaneously to higher and lower cooling capacities, the compressors must be switched on and off frequently. In the EP 3 203 164 B, for example, a damper is provided between the different compressors.

[0003] In the publication "Novel Turbo Compressor for Heat Pump Using Water as Refrigerant and Lubricant" by T. Shoyama et al. 2019, IOP Conf.: Mater. Sei. Eng. 604 011010, a compressor for a heat pump with a steam bypass V0 is described, which extracts the steam directly after the compressor (see Fig. 21 The steam path runs from the outlet of the second compressor C2 back to the inlet of the first compressor C1.

[0004] Typically, the power consumption of the first compressor stage serves as the control variable for the second compressor stage. This results in both compressor stages (first and second) contributing a similar pressure ratio to the overall pressure ratio, as they rotate at approximately the same speed. Consequently, the second compressor does not operate at optimal flow rates. This becomes particularly problematic at high pressure ratios because the ambient temperature and the control of the second compressor, influenced by the power consumption of the first compressor, lead to variations in steam volume flow rates. Condensation and re-evaporation in the intermediate circuit result in thermodynamic losses, meaning that the pressure ratios of the compressor stages do not fully contribute to the overall compression ratio. This is especially problematic for the second compressor.

[0005] From US Patent 9,557,080 B2, a refrigeration circuit is known, comprising a main circuit consisting of an evaporator, a first compressor, an intercooler, a second compressor, and a condenser connected in that order, and an evaporative-side recirculation path that allows refrigerant liquid retained in the evaporator to circulate through a heat exchanger for heat absorption. The intercooler is a heat exchanger that allows the refrigerant vapor compressed by the first compressor to be cooled by the refrigerant liquid. A supply path feeds a portion of the refrigerant liquid flowing in the first recirculation path to the intercooler, and a recovery path returns the refrigerant liquid from the intercooler to the evaporator.

[0006] From US patent 2014 / 0047862 A1, another refrigerant circuit for an air conditioner operating as a cooling device is known, comprising an evaporator, a first compressor, a vapor cooler, a second compressor, and a condenser connected in that order; a heat dissipation circuit that circulates a heat transfer medium between the condenser and a first heat exchanger, which releases heat to the atmosphere; and a heat absorption circuit that circulates a heat transfer medium between the evaporator and a second heat exchanger. The vapor cooler is a heat exchanger that exchanges heat between refrigerant vapor compressed by the first compressor and the heat transfer medium flowing in the heat dissipation circuit or the heat transfer medium flowing in the heat absorption circuit.

[0007] Furthermore, documents US 9 557 080 B2 and US 2014 / 047862 A1 each disclose a heat pump according to the preamble of claim 1.

[0008] The object of the present invention is to create 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 coolant.

[0009] This problem is solved by a heat pump according to claim 1.

[0010] The heat pump according to the present invention comprises, among other things, an evaporator for evaporating a fluid to obtain an evaporated fluid, wherein the evaporator has an evaporator sump; a compressor with a first compressor stage and a second compressor stage, wherein the compressor is arranged in the flow direction of the evaporated fluid in an operation of the heat pump between the evaporator and a condenser and is configured to compress the evaporated fluid to obtain compressed fluid; and a condenser for condensing the compressed fluid.Furthermore, the heat pump comprises an intercooler which is connected to an intercooling fluid supply line and which has an active element, wherein the active element is arranged and designed between the first compressor stage and the second compressor stage to effect an interaction between an intercooling fluid which can be supplied through the intercooling fluid supply line and a heated vaporous fluid which can be discharged from the first compressor stage, and wherein the intercooling fluid supply line extends from the evaporator sump to the active element.

[0011] It goes without saying that individual aspects described in relation to the heat pump can also be implemented as process steps, and vice versa. Further details are discussed in the following image description.

[0012] Preferred embodiments of the present invention are explained in detail below with reference to the accompanying drawings. These show: Fig. 1 a hydraulic diagram of the heat pump according to the invention; Fig. 2 an enlarged section of the hydraulic diagram Fig. 1 , where a steam damper (upper branch) and a steam bypass damper (lower branch) are shown; Fig. 3 a schematic test bench used to test the functionality of the heat pump compressors under real operating conditions; Fig. 4 a schematic diagram of an N-stage compaction process, where in the illustrated case N=3; Fig. 5 a hydraulic diagram of the N-stage compression; Fig. 6 a three-dimensional view of the heat pump according to the invention; Fig. 7 a top view ( Fig. 7a ) and a side view ( Fig. 7b ) of the cross-sectional reduction element and a connection of the cross-sectional reduction element ( Fig. 7c ); Fig. 8 a hydraulic diagram in which a circuit of indirect intercooling is shown; Fig. 9 a hydraulic diagram of indirect intercooling with an indirect heat exchanger; Fig. 10 a sketch of a side view of a heat exchanger tube; Fig. 11 a diametrically opposed perspective view of the heat exchanger; Fig. 12 a hydraulic scheme showing a feed for the intercooler, with the intercooler being fed from the evaporator sump; Fig. 13 a hydraulic diagram showing the supply of the intercooler, with sketched heat exchangers, wherein the intercooler is supplied from the evaporator sump; Fig. 14 a hydraulic scheme from which a feed for the intercooler is shown, with additional packing materials and / or additional intercoolers, wherein the intercooler is fed from the evaporator sump; Fig. 15 a compressor map; Fig. 16 a three-dimensional enveloping surface over a corrected mass flow; Fig. 17 a three-dimensional representation for determining the volume flow rate to calculate the corrected mass flow rate; Fig. 18 a hydraulic diagram which highlights temperature sensors for guiding the second compressor; Fig. 19 Diagram illustrating the control of the compressor stages of the heat pump; Fig. 20 a hydraulic diagram of a heat pump known from the prior art; and Fig. 21 A hydraulic diagram of a heat pump with steam bypass known from the state of the art.

[0013] Individual aspects of the invention described herein are set forth below. Figs. 1 bis 15 described. In the present application, identical reference numerals refer to identical or equivalent elements, and it is not necessary for all reference numerals to be repeated in all drawings.

[0014] The heat pump 100 according to the invention is described in conjunction with the attached Figuren 1 bis 19 described, whereby individual aspects of the heat pump according to the invention are described in the various Figuren 1 bis 19 They can be considered from different perspectives in order to highlight the individual aspects of the embodiments of the heat pump according to the invention. The individual aspects of the embodiments can be freely interchanged.

[0015] Fig. 1 shows a hydraulic diagram of the heat pump 100 according to the invention. In the hydraulic diagram according to Fig. 1 A first compressor stage 10 and a second compressor stage 20 are shown. 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, the steam channel has at least one inflection point in the depression 32, where the curvature is zero at the at least one inflection point. 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 operating element 42 of the intercooler 40 are coupled to each other via a first intercooler line 46. Fluid from the intercooler sump 44 can be guided via the first intercooler line 46 to the operating element 42 in order to spray compressed fluid from the first compressor stage 10, which is guided in particular in the vapor channel 30 to the second compressor stage 20, for the purpose of cooling. Furthermore, a second intercooler line 48 is provided extending 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.

[0016] The hydraulic diagram according to Fig. 1 Figure 50 further shows an evaporator 50 associated with the first compressor stage 10. The evaporator 50 comprises an evaporator sump 52. Above the evaporator sump 52, the evaporator 50 comprises an upper evaporator section 54 in which the first compressor stage 10 is arranged. A pipeline 56 is arranged in the evaporator 50 above the evaporator sump 52, which, according to the cross-section of the hydraulic diagram shown, Fig. 1 The pipe 56 is arranged in a matrix-like configuration above the evaporator sump 52. The pipe 56 above the evaporator sump 52 can carry fluid to be cooled. A sprinkler device 58 is arranged above the pipe to sprinkle the pipe 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 carries fluid from the evaporator sump 52 to the sprinkler device 58. After the pipe 56 has been sprinkled, the fluid discharged via the sprinkler device 58 can be collected in the evaporator sump 52 and fed back into a circuit of the heat pump 100.

[0017] The hydraulic diagram according to Fig. 1 Figure 60 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 exiting the first compressor stage 10 can be routed directly to the condenser 60 via the bypass channel 62. 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 associated with the condenser does not have a sprinkler system. The fluid to be heated flows through the pipe 56 associated with the condenser 60.

[0018] Further features of the hydraulic diagram according to Fig. 1 will be described below in connection with the other advantageous embodiments of the heat pump 100.

[0019] Fig. 2 shows an enlarged section of the hydraulic diagram according to Fig. 1 The figure shows a cross-sectional reduction element 70 (upper section) and a vapor transfer damper 90 (lower section). When the vapor transfer damper 90 is open, vaporous fluid can be guided from the condenser 60 to the evaporator 50 via a vapor guide line 92. When the cross-sectional reduction element 70 is open, vaporous fluid can be guided directly to the condenser 60 via the bypass channel 62. According to a preferred embodiment, the heat pump 100 includes the evaporator 50 for vaporizing a fluid to obtain an evaporated fluid, the evaporator 50 having the evaporator sump 52.Furthermore, the heat pump 100 comprises the condenser 60 for condensing evaporated fluid compressed by an N-stage compressor 10, 80, 20, the condenser 60 having a condenser sump 64, a condensation zone 66, and a holding zone 67 for retaining any vaporous fluid remaining after the condensation zone 66. The N-stage compressor 10, 20, 80 comprises N compressors, where N is a natural number greater than or equal to one, and the N-stage compressor 10, 20, 80 is arranged between the evaporator 50 and the condenser 60. The heat pump 100 also 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. Fig. 4 For example, an N-stage compressor, 10, 20, 80 is shown where N=3. Furthermore, the heat pump 100 includes a vapor supply line 92, which is 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 show, for example, a single steam guide line 92 in which the steam transfer flap 90 is arranged.

[0020] Fig. 3 Figure 1 shows a schematic test rig used to test the functionality of a single compressor of the 100-series heat pump under real operating conditions. According to the 300-series test rig... Fig. 3 The test rig 300 comprises a compressor 301 to be tested and at least one pressure sensor 302 for measuring the compression pressure of the compressed fluid. The test rig 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 rig 303 and a fluid line 15 leads out to supply fluid, in particular cooling water, to and from the pipeline 56. The flow rate in the fluid lines 15 is regulated depending on a condensing pressure. Preferably, the fluid lines 15 of the test rig 300 are connected to a cold water ring main (at a water temperature of approximately 17°C). The test rig 300 comprises a Jacob pipe, which includes a K4 condenser.Preferably, the Jacob tube has a height of up to 650 mm, particularly 600 mm, and a diameter of up to 600 mm, particularly 500 mm or 550 mm. The test rig also includes another Jacob tube, which has a height of up to 300 mm, particularly 240 mm, and a diameter of up to 600 mm, particularly 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 packing element 7 is arranged above the fluid level 51. The packing element 7 preferably comprises several individual packing elements designed to allow the vapor to flow over a larger surface area, thus advantageously facilitating condensation.The fluid level 51 in the container 45 is set such that a gap exists between the liquid fluid and the pipe wall in a pipe 306, which supplies the fluid to the container 45. This gap forms a vapor flow 304 between the water level and the pipe wall. The pipe 306 connects an outlet of the compressor 301 under test to an inlet of the container 45, allowing vaporized fluid from the compressor 301 under test to be returned to the container 45. The pipe 306 is specifically designed in two sections, with a throttle valve 307 arranged between the two sections to adjust the resistance of the vaporized fluid. The evaporation temperature is also set 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 rig 300 also features a geometric structure that serves as a return 308 for the condensed fluid from the compressor 301 under test. A spray element 43 for irrigating the evaporated fluid is also provided in the pipe 306. Fluid is pumped from the container 45 into the spray element 42 of the test rig 300 by means of a pump 310 and an associated line. The test rig also includes a sensor 309, which is specifically a volumetric flow sensor for measuring the volumetric flow rate of the evaporated fluid. A connected control unit receives the measurement signals from the volumetric flow sensor and uses this signal, among other things, to determine the control signal for setting the target speed of the compressor.

[0021] Preferably, the holding area 67 in the condenser 60 is arranged between the condensation area 66 and the condenser sump 64 containing condensed working fluid. An opening 65 of the steam guide line 92 is arranged in the holding area 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 section that projects through the condenser sump 64 into the holding area 67 in order to direct evaporated, i.e., non-condensed, fluid via the steam guide line 92 to the evaporator 50.

[0022] 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 60 through a wall, preferably a bottom. Figs. 2 and 4For example, it is shown how the steam guide line 92 extends through the bottom of the condenser sump 64. It is conceivable that the steam guide line 92 extends through a wall, in particular a side wall, through the condenser sump 64.

[0023] Preferably, the condenser 60 has 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 the opening 65 of the steam supply line 92, and wherein an intake port 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 is also referred to herein as pipeline 56.

[0024] Preferably, the steam guide line 92 has an opening 55 into the evaporator 50, the opening 55 being located above the evaporator sump 52 in the evaporator 50. The steam guide line 92 thus has two openings 55, 65, one opening passing through the condenser sump 64 and the other opening 55 opening into the evaporator 50 above the evaporator sump 52. This is, for example, Figs. 2 and 4 to be taken.

[0025] Preferably, a tube bundle 56a for the liquid to be cooled and a spray device 58 for spraying the tube bundle 56a are arranged in the evaporator 50, wherein the opening 55 of the vapor supply line into the evaporator 50 is arranged such that vaporous fluid entering the evaporator 50 through the opening 55 laterally impinges on the tube bundle 56a, and / or that the vaporous fluid exiting the vapor supply line 92 enters a spray area 57 which is at least partially sprayed by the spray device 58. For example, Figs. 1 , 2 or 4As can be seen, fluid from the evaporator sump 52 is supplied to the sprinkler device 58 via a first evaporator line 59 between the evaporator sump 52 and the sprinkler device 58. After the tube bundle 56a in the evaporator 50 has been sprinkled, the fluid used for sprinkler application can be collected again through the evaporator sump 52 and fed back into a circuit of the heat pump 100.

[0026] 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 the Figs. 1 , 2 or 4 As can be seen, 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 each other or individually not operated at all.

[0027] Preferably, the N-stage compressor comprises 10, 20, 80 N compressors connected in series, wherein the vapor supply line 92 is designed as a single vapor supply line 92 and carries the vaporous fluid, which has been brought from a last stage into the condenser 60, from the condenser 60 into the evaporator 50 (see Figs. 2 , 4 und 5 ). In Fig. 5 A hydraulic diagram of the N-stage compression system is shown. Fig. 5 For example, the cross-sectional reduction element 70 is shown as a valve. The N-stage compressor 10, 20, 80 is shown as N compressors connected in series, which are connected between the evaporator 50 and the condenser 60.

[0028] 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 pair of compressors to cool the vaporous fluid (see Fig. 4 ). Each intercooler 40 comprises a working element 42 and an intercooler sump 44 (see Fig. 4 The intercooler sump 44 is designed to collect fluid, and the active element 42 of the respective intercooler 40 is connected to each other via a first intercooler line 46, whereby fluid from the intercooler sump 44 can be guided to the active element 42 via the first intercooler line 46. After passing through the respective active element 42, the fluid can be collected by the intercooler sump 44. The fluid can then be fed back into a cycle of the heat pump 100. Fig. 5 For the sake of clarity, it was omitted to show an intercooler 40 between each of the compressors of the N-stage compressor 10, 20, 80.

[0029] 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 active element 42, wherein the active element 42 is designed to effect an interaction between an intercooling fluid, which can flow into the active element 42 from the intercooling sump 44 or from the evaporator sump 52 or from the condenser sump 64 via a supply line, in particular the first intercooler line 46, and a heated vaporous fluid that can be discharged from the compressor, wherein the interaction in particular causes the vaporous fluid discharged from the compressor to be cooled by the intercooling fluid (see Figs. 2 and 4 ). Before the vaporous fluid is drawn into the vapor channel 30 by the second compressor stage 20, the vaporous fluid is cooled by the intercooler 40.

[0030] Preferably, each intercooler 40 has an intercooling sump 44 and an active element 42 and is arranged in its own recess 32 in the steam channel 30. In particular, each intercooler 40 has its own first intercooler line 46 to the active element 42. The first intercooler line 46 can also be referred to as a feed line. Particularly in the case of several intercooling sumps 44, the feed lines, i.e., the first intercooler lines 46, can also be interconnected (not shown in the figures), so that the feed lines then form only one feed line overall.

[0031] Preferably, the steam channel 30 between two compressors has a curved shape with the depression 32, so that fluid from the steam channel 30 flows past the intercooling sump 44. Condensing fluid can be collected in the intercooling sump 44.

[0032] Preferably, the steam guide line 92 and the steam channel 30 are fluidically separated from each other. Fluidically separated in this context means that the steam guide line 92 and the steam channel 30 are not joined together in a way that would allow the fluid to mix. Therefore, the steam guide line 92 and the steam channel 30 are in the Figs. 2 and 4 For example, the steam guide line 92 and the steam channel 30 are shown with dashed lines to illustrate that they are separate. 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 channels 30 is / are located between the evaporator 50 and the condenser 60 in the upper circuit. The steam guide line 92 is located between the evaporator 50 and the condenser 60 in the lower circuit.

[0033] Preferably, 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. Fig. 5 The diagram schematically sketches n+1 compressors leading to the first compressor 10. The n+1 compressor is drawn with dashed lines, indicating the addition of the individual compressors of the N-stage compressor 10, 20, 80. In this case, the first compressor stage 10 comprises the first compressor. The second compressor stage comprises the second compressor. An nth compressor stage comprises an nth compressor, where n is a natural number.

[0034] Preferably, a bypass flap 90 is arranged in the steam guide line 92, which can be moved to an open position, an intermediate position, or, to prevent the steam from entering the evaporator, to a closed position to guide the vaporous fluid from the condenser 60 to the evaporator 50. Similar to the cross-sectional reduction element 70, the bypass flap 90 can be designed as an orifice plate, a hinged door, a check valve, or a valve, as for example in Fig. 5 The heat pump 100 is designed as shown. It also includes a control unit for controlling the bypass flap 90 into the open position, the intermediate position, or the closed position.

[0035] Preferably, the bypass flap 90 is designed as a controlled bypass valve, which can be addressed by the control unit in order to operate close to a boundary line of a compressor characteristic curve 170 assigned to the N-stage compressor 10, 20, 80. The design of the bypass flap 90 as a controlled bypass valve is, for example, in Fig. 5 shown. The bypass valve 90 can also be referred to as a steam transfer valve 90.

[0036] A compressor characteristic curve 170 assigned to the N-stage compressor 10, 20, 80 defines a relationship between a pressure ratio and a mass flow rate. Such a compressor characteristic curve 170 is, for example, in Fig. 15 The compressor map 170 is to be understood as a three-dimensional field, with the third dimension represented by shading in the two-dimensional coordinate system spanned by the pressure ratio PiC and the, in particular corrected, mass flow rate 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, and 80. The compressor map 170 includes a surge line 171, which represents a monotonically increasing function between the mass flow rate and the pressure ratio. The bypass valve 90 is controlled to ensure that, for a given mass flow rate, the pressure ratio is less than a limit pressure ratio, which is assigned to that specific mass flow rate according to the function. Fig. 15 The dotted lines show 172 lines of equal rotational speed at a measured evaporation temperature of 18° degrees.

[0037] Preferably, the control system is configured to move the bypass valve 90 into a closed position, an open position, or an intermediate position in order to maintain the load of the N-stage compressor 10, 20, 80 at least at a setpoint during operation. The surge limit 171 can, in particular, describe the setpoint, which can also be a function of the mass flow rate WcCorr. Specifically, the control system is configured to actuate the bypass valve 90 such that the heat pump 100 operates essentially along the surge limit 171 or in a range shifted slightly towards higher mass flow rates WcCorr, thus advantageously preventing the compressor from operating below its surge limit.

[0038] Preferably, the control system is configured to open the bypass valve 90 when the load of the N-stage compressor 10, 20, 80 falls below the load setpoint; or to close the bypass valve 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 valve 90 depending on the degree to which the load setpoint is undershot. This allows the heat pump to operate essentially along the pumping limit 171. For example, the bypass valve 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 be done starting from either the open or the closed position of the bypass valve 90.The load setpoint specifies a load of the heat pump 100 during operation, which must be achieved at least by the N-stage compressor 10, 20, 80.

[0039] For a two-stage compressor, 10 or 20 is preferred, such as this one in Fig. 2 As shown, the second compressor is switched off when the bypass valve 90 is open, or in the case of a multi-stage compressor (as, for example, in Fig. 4 oder 5 (As shown) all stages except the first stage 10 are switched off when the bypass valve 90 is open. Therefore, as soon as all compressor stages except one are switched off, the bypass valve 90 is opened. If at least one additional compressor stage is switched on besides the one already operating, the bypass valve 90 is closed or, if necessary, moved to an intermediate position. For example, the first compressor 10 can be controlled depending on the speed of a compressor drive in order to adjust the speed of the first compressor stage 10 to the required output of the first compressor 10.

[0040] Fig. 6 Figure 1 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 each other via the curved steam channel 30, the steam channel 30 having the intercooler 40. Furthermore, the view from Fig. 6 It can be seen that the first compressor stage 10 is connected to the condenser 60 via the bridging channel 62, with the cross-section reducing element 70 being arranged in the bridging channel 62. The heat pump 100 has also already been described in relation to Fig. 1 described. According to the view of Fig. 6 Not all details can be gleaned from it, such as the hydraulic diagram. Fig. 1 The relative sizes are revealed in the Fig. 6 However, as can be seen from the heat pump 100 shown, the steam channel 30, for example, has a mean diameter that corresponds approximately to half the width of the condenser. Therefore, to describe the Fig. 6 also on the description to Fig. 1 or another figure showing a hydraulic diagram of the heat pump 100 according to the invention.

[0041] A preferred embodiment of the heat pump 100 comprises an evaporator 50 for evaporating a fluid to obtain evaporated fluid. The heat pump 100 further comprises a condenser 60 for condensing a compressed fluid. The heat pump 100 also includes 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 between the evaporator 50 and the condenser 60 in the operation of the heat pump 100 and is configured to compress the evaporated fluid to obtain compressed fluid.As proposed, 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-sectional reduction element 70 is arranged in the bypass channel 62 to adjust its cross-section and regulate the flow of compressed fluid from the first compressor stage 10 to the condenser 60. Thus, after exiting the first compressor stage 10, the compressed fluid can be directed directly to the condenser 60, provided the cross-sectional reduction element 70 is in an open position. Specifically, when the second compressor stage 20 is not operating, i.e., when it is switched off, the cross-sectional reduction element 70 is in the open position.

[0042] 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 passing through the steam channel 30 if the gaseous fluid passing through the steam channel 30 condenses. Because the container 45 is arranged in the depression 32, condensed fluid can be automatically directed into the container 45 by utilizing the force of gravity, in particular without any further technical means.

[0043] Preferably, the bypass channel 62 has an opening into the first compressor stage 10, wherein the first compressor stage 10 has an intake port 12 for drawing in the vaporized fluid and a guide chamber 14 for directing the vaporous compressed fluid into the bypass channel 62. The intake port 12 can be conical, with a first diameter arranged in an intake area of ​​the intake port 12 for drawing in the fluid and a second diameter of the intake port 12 directly adjoining the guide chamber 14. In particular, the first diameter is larger than the second diameter. In this 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.

[0044] Preferably, the condenser 60 has a pipe 56. The pipe 56 is preferably designed as a tube bundle 56a or a spiral pipe arrangement 56b, through which the liquid to be heated can flow, wherein the tube bundle 56a or the spiral pipe arrangement 56b is arranged laterally with respect to a further opening of the bridging channel 62, and wherein an intake port 12 of a compressor of the second compressor stage 20 is arranged above the tube bundle 56a or the spiral pipe arrangement 56b.

[0045] Preferably, the further opening of the bridging channel 62 is arranged such that vaporous fluid entering the condenser 60 through this further opening impinges laterally on the tube bundle 56. Because the pipe 56, i.e., the tube bundle 56a or the spiral pipe arrangement 56b, is arranged laterally with respect to a further opening of the bridging channel 62 in the condenser 60, vaporized and compressed fluid, after passing through the bridging channel 62, directly enters the pipe 56, where it can be cooled. Since the pipe 56 can carry fluid to be heated, heat is transferred from the vaporized and compressed fluid, which impinges laterally on the pipe 56 from the bridging channel 62, via the pipe 56 to the fluid to be heated flowing through the pipe.When the vaporized and compressed fluid comes into contact with the pipe 56, it is cooled, which can lead to condensation. Fluid that has condensed on the pipe 56 can, particularly due to gravity, drip into the condenser sump 64.

[0046] Preferably, the cross-sectional reduction element 70 is configured to assume a closed or an open position depending on the operation of the second compressor stage 20, wherein the cross-sectional reduction element 70 is configured to assume the closed position when the second compressor stage 20 is switched on, or the open position when the second compressor stage 20 is switched off. Depending on the operation of the second compressor stage 20, the cross-sectional reduction element 70 can be moved into the closed or the open position. It is also conceivable to move the cross-sectional reduction element 70 into an intermediate position, i.e., a position between the open and the closed positions, particularly when the second compressor stage 20 is ramped down (switched off) or ramped up (switched on).

[0047] Preferably, the cross-sectional reduction element 70 is pre-tensioned in the closed position by means of a spring element (not shown). If the second compressor stage 20 is switched off, the pre-tensioned spring element can relax, particularly due to the absence of a suction of compressed fluid from the first compressor stage 10 through the vapor channel 30, so that the cross-sectional reduction element 70 moves into 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.

[0048] Preferably, the cross-sectional reduction element 70 is a flap or a cover or a hinged door or a backdraft damper. Fig. 7 shows in Fig. 7a a top view of the cross-sectional reduction element 70 and in Fig. 7b A side view of the cross-sectional reduction element 70. The cross-sectional 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, the figure). Fig. 1 , Fig. 2 or Fig. 4 ). A diameter 72 of the cross-sectional reduction element 70 (as in Fig. 7a (shown) can correspond to the 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-sectional reduction element 70 (as shown in Fig. 7b (as shown) the diameter 72 of the cross-sectional reduction element 70 is smaller than the diameter of the bridging channel 62. Fig. 7c shows an excerpt from Fig. 7b Regarding a connection of the cross-sectional reduction element 70 for controlling the cross-sectional reduction element 70 into the open or closed position. Further requirements for the cross-sectional reduction element 70 can be found, for example, in DIN EN ISO 5211.

[0049] Preferably, the heat pump 100 has a control unit for controlling the cross-sectional reduction element 70 to the open or closed position. Depending on whether the cross-sectional reduction element 70 is designed as a flap, orifice, hinged door, or non-return valve, the control unit is configured to actuate the flap, orifice, hinged door, or non-return valve. For example, if the element is designed as an orifice, the control unit is configured to increase or decrease the diameter of the orifice.

[0050] Preferably, the first compressor stage 10 is configured to build up a maximum achievable pressure, and the cross-sectional reduction element 70 is configured to assume the open position when the pressure ratio between the condenser pressure T12 and the evaporator pressure Th is less than the maximum achievable 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 T12 and the evaporator pressure Th can be calculated, for example, by measuring temperatures. In particular, the temperature Th in the evaporator sump 52 and the temperature T12 in the condenser sump 64 can each be measured in order to determine the pressure ratio between the condenser pressure (T12) and the evaporator pressure Th. Here, the measured temperature Th in the evaporator sump 52 is associated with the evaporator pressure Th.Furthermore, the measured temperature TI2 in the condenser sump 64 is associated with the condenser pressure Tl2. Therefore, the corresponding measured temperature reference symbols Th and Tl2 are used as reference symbols for the respective pressures in the condenser sump 64 and evaporator sump 52, respectively. Fig. 18 shows, for example, where the temperatures Th and Tl2 are measured.

[0051] Preferably, the cross-sectional reduction element 70 is configured to assume the closed position when the pressure ratio between the condenser pressure Tl2 and the evaporator pressure Th is greater than the maximum achievable 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. Upon reaching 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 associated with the condenser 60 is configured analogously to the guide chamber 14 associated with the evaporator 50 in the upper evaporator head 54.

[0052] 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. Fig. 4 For example, three compressor stages 10, 20, 80 are shown. According to the illustration in Fig. 4 Here, N equals 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, in the case of N compressor stages, two adjacent compressor stages are each connected via a steam channel 30 (see figure). Fig. 4 , where N=3 is shown, or Fig. 5 ).

[0053] Fig. 8 shows a hydraulic diagram according to Fig. 1 , in which a circuit of an indirect intercooler 8 is shown. The indirect intercooler 8 is used in a preferred embodiment of the heat pump 100.

[0054] In the preferred embodiment of the heat pump 100, as described in Fig. 8 As shown, the heat pump 100 comprises the evaporator 50 for evaporating a fluid to obtain an evaporated fluid, the evaporator 50 having the evaporator sump 52. The heat pump 100 further comprises the condenser 60 for condensing a compressed fluid, the condenser 60 having the condenser sump 64. The heat pump 100 also comprises the compressor with the first compressor stage 10 and the second compressor stage 20, the compressor being arranged in the flow direction of the evaporated fluid between the evaporator 50 and the condenser 60 in operation of the heat pump 100 and being configured to compress the evaporated fluid to obtain the compressed fluid. The heat pump, as shown in Fig. 8 The heat pump, as shown, further comprises a container 45 for collecting an intercooling fluid. In particular, the container 45 is an intercooling sump 44. The heat pump further comprises a heat exchanger 82 with a pipe 56 configured to carry the intercooling fluid 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 to cool vaporous fluid in the flow region 11. Fig. 8 It is shown, for example, 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 shown in Fig. 8 Pipeline 56 is located in the area of ​​the first compressor stage 10. As in Fig. 14 As shown, the heat exchanger 82 can be arranged for indirect cooling between the first compressor stage 10 and the second compressor stage 20, particularly where an intercooler 40 and / or a further intercooler 4 and / or a yet another intercooler 5 can be provided.

[0055] Preferably, the pipe 56 is metallic, and more preferably, it is made of 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.

[0056] The pipe 56 of the heat exchanger 82 is, for example, in Figs. 8 bis 10 As shown. Preferably, the pipe 56 of the heat exchanger 82 has a section in which the pipe 56 runs in a spiral or spring-like manner, wherein the spring-like or spiral-like section has turns 83 with different turn spacings. In a spring-like pipe 56, the diameter from one turn to the next is constant. In a spiral-like pipe 56, the diameter of one turn differs from the diameter of a subsequent turn. A spiral-like pipe 56 can be designed as a conical spiral. A spring-like pipe 56 is formed by a central projection of a helix 101 onto a plane perpendicular to the helix axis 102, as is the case, for example, in Fig. 10 is shown. Fig. 10 schematically branches off the heat exchanger 82.

[0057] Preferably, the first compressor stage 10 has an intake port 12 for drawing in the evaporated fluid and a guide chamber 14 for directing the vaporous fluid into the flow chamber 11. The flow chamber 11 comprises a volume of an upper evaporator section 54, the vapor channel 30, and the bypass channel 62. The flow chamber 11 includes those areas of the heat pump 100 into which evaporated and compressed fluid can flow.

[0058] For example, in Figs. 8 and 9 As shown, the pipe 56 of the heat exchanger 82 is arranged around the intake port 12 of the first compressor stage 10, wherein the pitch between two turns 83 in an inflow region of the vaporous fluid of the first compressor stage 10 is larger than in an outflow region of the vaporous fluid into the guide chamber 14. This is, for example, in the Figs. 8 and 9This can be seen. Because the pitch between two turns 83 is larger in the inflow region, the flow velocity of the steam is only slightly reduced. In the outflow region of the vaporous fluid into the guide chamber 14, the pitch between two turns 83 is larger to improve, and in particular increase, the cooling of the steam.

[0059] Fig. 11 Figure 82 shows, for example, a diametrical perspective view of the heat exchanger. Fig. 11 It can be deduced that it is also conceivable that in the outflow region of the vaporous fluid from the guide space 14 the winding distance between two windings 83 is smaller than in the inflow region.

[0060] Preferably, a steam channel 30 is arranged between the pipeline 56 and the container 45, wherein the outflow region 11, which is also referred to as the flow region 11, is connected to the steam channel 30 in order to guide the vaporous fluid through the container 45 via the steam channel 30. "Guide through the container 45" is to be understood as "guide over the container 45." During operation of the second compressor stage 20, the vaporous fluid is drawn in by the second compressor. This causes the vaporous fluid to be guided through the steam channel 30, as is the case, for example, with the Fig. 8 can be seen from this.

[0061] Preferably, a fluid line channel 15 extends laterally from the outflow area 11 into the steam channel 30 in order to supply the intercooling fluid flowing through the heat exchanger 82 to the container 45 via the steam channel 30 (see Fig. 8 The outflow section 11 extends from an outlet of the first compressor stage into the steam channel 30 and into the evaporator section 54. The fluid line channel 15 extends through a wall, in particular a bottom, of the upper evaporator section 54. In a bottom region of the upper evaporator section 54, the intercooling fluid flowing through the heat exchanger 82 collects and forms a fluid level 51. If the fluid level 51 of the upper evaporator section 54 lies above the extent of the fluid line channel 15 through the wall, the intercooling fluid can flow into the steam channel 30 via the fluid line channel 15, particularly due to gravity.

[0062] Preferably, the intake port 12 has a funnel shape with a maximum diameter 16 and a minimum diameter 17 opposite each other, 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 abut the bottom of the upper evaporator section 54, whereby the intercooling fluid flowing through the heat exchanger 82 is collected outside the intake port 12 of the first compressor stage 10 in the bottom region (see Fig. 8 ).

[0063] Preferably, the guide chamber 14 is curved at one end, which transitions into the upper evaporator section 54, in order to direct the vaporous fluid flowing through the guide chamber 14 in a direction opposite to the gas flow direction in the intake port. 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 supply line 92 if the second compressor stage is not in operation.

[0064] Preferably, the guide chamber 14 has a volume with a circle or an oval as its base. The guide chamber 14 is arranged essentially perpendicular to the minimum diameter 16 of the intake port 12 of the first compressor stage 10. The guide chamber is particularly located in the upper evaporator section 54. Furthermore, the second compressor stage 20 also has a guide chamber 14, which is arranged essentially perpendicular to the minimum diameter 16 of the intake port 12 of the second compressor stage 20. The guide chamber 14 of the first and second compressor stages 10 and 20 can also have a different, arbitrarily shaped base.

[0065] Preferably, a further heat exchanger 82 is arranged in the steam channel 30 at a distance from the outlet area 11. Preferably, the further heat exchanger 82 is 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, the steam channel 30 being located between a pressure side of the first compressor stage 10 and a suction side of the second compressor stage 20. Preferably, the steam channel 30 has a curved shape with a depression 32. Preferably, the container 45 is arranged in the depression 32 so that liquid intercooling fluid flows from the steam channel 30 into the container 45. This can be Fig. 8 For example, the fluid can be extracted from the container. Preferably, the heat exchanger 82 and / or the further heat exchanger 82 has / have an outer surface that is at least partially contoured and in contact with the vaporous fluid to improve heat transfer between the heat transfer medium 82 and the vaporous fluid. Preferably, the heat exchanger 82 and / or the further heat exchanger 82 has / have an inner surface that is at least partially contoured and in contact with the fluid from the container 45 to create turbulent flow on its inner surface. The contoured inner and / or outer surfaces can have grooves and / or reliefs, i.e., recesses / protrusions of any shape.

[0066] Preferably, for self-regulation of the fluid level, the condenser sump 64 and / or the evaporator sump 52 and / or the container 45 are each fluid-conductingly connected to one another via a fluid line channel 15, so 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 adjusts itself passively due to the geometric arrangement and the connection of the individual sumps 52, 45, 64 to one another (see, for example, Figure 1). Figs. 1 , 2 , 8 , or 12(to 14). Self-regulation in this context refers to passive regulation, i.e., without further technical means. However, it is also conceivable to provide active regulation of the fluid level in sumps 52, 45, 64 by means of pumps, which could, for example, include a control system and level sensors that detect the fluid level in sumps 52, 45, 64.

[0067] Preferably, a return line 2, which is also referred to as a fluid line channel 15, extends from the condenser sump 64 into the container 45 or the intercooling sump 44 for conveying fluid. Furthermore, preferably, a fluid line channel 15 extends from the container 45 or the intercooling sump 44 into the evaporator sump 52 for conveying fluid, wherein the fluid line channel 15 extends laterally from the bottom of the container 45 or the intercooling sump 44 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. Preferably, the heat pump 100 has an intercooling circulation pump 22 to supply intercooling fluid from the container 45 to the pipeline 56.In this embodiment of the heat pump 100, the intercooling fluid supply line 3 can extend from the tank 45 to the pipeline 56 (see . ). Fig. 8 ). In the embodiments of the Figs. 12 , 13 and 14 The intercooling circulation pump 22 can supply intercooling fluid from the evaporator sump 52 to the pipeline 56.

[0068] Fig. 9 shows a hydraulic diagram of the indirect intercooling 8 with indirect heat exchanger 82. Fig. 9 In simplified terms, it can be seen that the steam channel 30 extends from the upper evaporator section 54, in which the first compressor of the first compressor stage 10 is located and in which the heat exchanger 82 may be located, to the second compressor stage 20. Compressed fluid exiting the first compressor stage 10 can thus be conveyed via the steam channel 30 to the second compressor stage 20. Furthermore, the fluid line channel 15 extends from the heat exchanger 82, through which the fluid flowing through the heat exchanger 82 can be directed into the container 45. The legend of the Fig. 9 The diagram further shows that the fluid lines 15 and the intercooling fluid supply line 3 carry liquid fluid, i.e., water in this case. It also shows that the steam channel 30 between the first and second compressor stages 10, 20 is an active steam path. An active steam path means that the second compressor stage 20 is in operation, so that compressed fluid leaving the first compressor stage is drawn 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 steam path. An inactive steam path means that the second compressor stage 20 is out of operation and the cross-sectional reduction element 70 is open, so that compressed fluid leaving the first compressor stage is routed directly into the condenser 60 via the bypass channel 62.

[0069] 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, wherein the compressor is arranged in the flow direction of the evaporated fluid between the evaporator 50 and the condenser 60 in operation of the heat pump 100 and is configured to compress the evaporated fluid to obtain a compressed fluid. The condenser 60 serves to condense the compressed fluid.Furthermore, the heat pump 100 comprises the intercooler 40, which is connected to an intercooling fluid supply line 3 and has the active element 42, wherein the active element is arranged and configured between the first compressor stage 10 and the second compressor stage 20 to effect an interaction between an intercooling fluid, which can be supplied through the intercooling fluid supply line 3, and a heated vaporous fluid that can be discharged from the first compressor stage 10. The intercooling fluid supply line 3 extends from the evaporator sump 52 to the active element 42. Such a preferred embodiment of the heat pump is shown as a hydraulic diagram, for example, in [reference]. Fig.12 shown. Fig. 12 The hydraulic diagram further illustrates the supply of the intercooler, which is fed from the evaporator sump 52. Fluid from the evaporator sump 52 is supplied to the working element 42 via the intercooler fluid supply line 3, so that the fluid from the evaporator sump 52 can be used to spray evaporated and compressed fluid passing through the intercooler 40, which is located in the vapor channel 30.

[0070] Preferably, the intercooling fluid supply line 3 extends through an opening in the evaporator sump 52, the opening of the intercooling fluid supply line 3 being located below a fluid level 51 of the fluid in the evaporator sump 52. The fluid from the evaporator sump 52 can flow into the intercooling fluid supply line 3, particularly by gravity. In particular, the intercooling fluid supply line 3 does not require a control system for supplying fluid from the evaporator sump 52. However, it is conceivable to provide a control system for supplying liquid fluid to the intercooling fluid supply line 3.

[0071] As in Fig. 12 As shown, the intercooler 40 preferably has an intercooling sump 44, wherein a return line 2 or a fluid line channel 15 extends from a bottom of the intercooling sump into the evaporator sump 52, preferably laterally. In particular, the heated vaporous fluid that can be discharged from the first compressor stage 10 and the intercooling fluid are each taken from the evaporator sump 52. Preferably, a further return line 1, which can also be referred to as a fluid line channel 15, extends from the condenser sump 64 directly into the evaporator sump 52, preferably laterally, for returning fluid from the condenser sump 64 to the evaporator sump 52. In particular, the return line 2 and the further return line 1 are fluidically separated from each other."Fluidically separated" means that the fluid from return line 2 and the further return line 1 cannot mix in one line, but are only mixed together in the evaporator sump 52. Regarding lines 1, 2 and 3, see... Figs. 12 and 14 an identical arrangement of lines 1, 2, 3.

[0072] Fig. 14 shows another preferred embodiment of the heat pump 100, as described in Fig. 12 shown. Fig. 14 shows a hydraulic diagram as in Fig. 12 , from which a feed of the intercooler emerges, with additional packing materials 7 and / or additional further intercoolers 4, 5, wherein each intercooler 4, 5 is fed from the evaporator sump 52.

[0073] According to a further preferred embodiment of the heat pump, as described in Fig. 14 As shown, 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 vapor duct 30 between the evaporator 50 and the condenser 60. The further intercooler 4, 5 can, in particular, be arranged downstream of an outlet of the first compressor stage 10.

[0074] As in the embodiments according to Fig. 12 and 14As shown, the intercooling sump 44 is designed to collect fluid that can flow through the intercooling fluid supply line 3, wherein the fluid from the intercooling sump 44 can be supplied to the evaporator sump 52 via the return line 2, 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 within 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.Preferably, the intercooling fluid supply line 3 or a motor cooling line 33 is arranged from the evaporator sump 52 to a motor cooling unit 34 of the first compressor stage 10 in order to convey fluid from the evaporator sump 52 to the motor cooling unit 34 for cooling a motor M associated with the first compressor stage 10. In particular, the intercooling fluid supply line 3 and / or the motor cooling line 33 extend from the evaporator sump 52 via the motor cooling unit 34 of the first compressor stage 10 to the operating element 42 in order to convey fluid from the evaporator sump 52 to the motor cooling unit 34 for cooling a motor M associated with the first compressor stage 10 and to the operating element 42 (see . Figs. 12 and 14 ).

[0075] How the Figs. 12 and 14It can also be seen that a further motor cooling line 35 is arranged from the evaporator sump 52 to a further motor cooling line 36 of the second compressor stage 20 in order to direct fluid from the evaporator sump 52 to the further motor cooling line 36 for cooling a motor M assigned to the second compressor stage 20. The motors M, which are 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 intercooler sump 44. The fluid from one of the intercooler sumps 44 is in turn cooler than the fluid from the condenser sump 64.

[0076] For example, the Figs. 1 , 2 , 8 or 12 bis 15 Preferably, a ball bearing adapter line 74 is arranged from the intercooling sump 44 to a ball bearing adapter 76, which is assigned to the first compressor stage 10, in order to direct fluid from the intercooling sump 44 to cool 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 direct fluid from the ball bearing adapter 76 to the first compressor stage 10 in order to spray the compressed fluid in the first compressor stage 10 with the fluid from the ball bearing adapter 76.

[0077] Preferably, a ball bearing adapter line 74 is arranged from the condenser sump 64 to a ball bearing adapter 76, which is assigned to the second compressor stage 20, in order to direct fluid from the condenser sump 64 to cool 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 direct fluid from this ball bearing adapter 76 to the second compressor stage 20 in order to spray the 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 cooling fluid from the intercooling fluid supply line 3 and thus be connected in series or parallel to the same line to which the motor cooling 36 is also connected.

[0078] Preferably, at least one packing material 7 is arranged in a region around the first compressor stage 10 for heat dissipation, in particular for increasing the surface area and thus for optimized cooling of the steam. The at least one packing material 7 is arranged in particular around the intake nozzle 12 of the first compressor stage 10 (cf. with Fig. 14 In a particularly advantageous embodiment, the at least one packing body comprises numerous individual packing bodies distributed around the intake port 12 of the first compressor stage 10.

[0079] For example, the Fig. 14 As can be seen, a 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 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 through the further intercooler 5 and / or the intercooler 40. It is conceivable that the heat pump 100 comprises only the further intercooler 4 and the further intercooler 5 (see Fig. 14 It is also conceivable that the heat pump 100 only includes the intercooler 40 (see Fig. 12 It is also conceivable that the heat pump 100 comprises only the intercooler 40 and the further intercooler 4 or the yet another intercooler 5. In an embodiment not shown, it is also possible that the intercooler 5 extends over the entire length of the steam channel 30, thus resulting in particularly efficient cooling of the steam flowing past it.

[0080] 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 steam. Figs. 8 bis 10 For example, the indirect cooling 8 by the heat exchanger 82 is shown. The heat exchanger 82 has already been discussed in detail, to which reference is made here.

[0081] 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 further intercooler 5 are arranged at a distance from an intake area of ​​the second compressor stage 20. As, for example, in Fig. 14 As can be seen, the intercooler 40 and / or the further intercooler 4 and / or the yet another 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 to the sink 32.

[0082] To regulate a fluid level, i.e., a fluid level 51, the condenser sump 64 and / or the evaporator sump 52 and / or the intercooler sump 44 can each have a level control system. Preferably, a level control system can be omitted if the fluid level 51 in the individual sumps 52, 44, 64 regulates itself via the height of the outlets, i.e., if self-regulation, as already described, is possible. Then the fluid level 51 does not need to be actively controlled. Outlets in this context refer, for example, to the opening 65 of the steam supply line 92 into the condenser 60, and / or the opening 65 of the return line 2 into the intercooler sump 44, and / or the opening 65 of the intercooler fluid supply line 3 into the evaporator sump 52, as is the case, for example, in Figs. 12 , 13 and 14 shown.

[0083] As already explained, Fig. 15 a compressor characteristic map 170 of an N-stage compressor, wherein the compressor characteristic map 170 defines a relationship between a pressure ratio and a mass flow rate.

[0084] Fig. 16 Figure 1 shows a three-dimensional envelope 180 over a corrected mass flow rate, where the dotted lines represent measured speed characteristics 181. The speed characteristics 181 depend on the corrected mass flow rate WCcorr and the compression ratio PiC. Similar to in Fig. 15 is in Fig. 16 The surge line 171 is shown as a function of the corrected mass flow rate and the compressor ratio. The envelope 180 is represented as a fit surface (3D fit) which has been adapted to the measured speed characteristics 181. The envelope 180 initially increases with increasing corrected mass flow rate and increasing speed, and is represented by a three-dimensional monotonically increasing function. After reaching a mass flow rate of approximately 0.8, the envelope 180 exhibits a monotonically decreasing profile.

[0085] Fig. 17 Figure 1 shows a three-dimensional representation for determining a volume flow rate to calculate the corrected mass flow rate. The volume flow rate is given by a function that depends on the output electrical power Pi and the rotational speed of the compressor stage 10, 20. Preferably, 100 identical compressor stages 10, 20 are used in the heat pump. It is also conceivable to use compressor stages 10, 20 that differ from each other.

[0086] The volume flow rate cannot be measured directly. Instead, it is determined indirectly via a stored 3D characteristic map 190, which is specific to a given compressor drive. The volume flow rate is derived as a function of the electrical power input Pei and the rotational speed of the compressor drive using the 3D characteristic map 190 (see dotted curves 191), in which the measured values ​​191 are entered. After determining the volume flow rate, the mass flow rate can be corrected, in particular by applying knowledge of the molar mass of the fluid at a given pressure and temperature.

[0087] 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 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.Furthermore, the heat pump 100 comprises a data acquisition device 95 for acquiring a first value P1, which corresponds to or depends on a first pressure ratio between an inlet of the first compressor stage 10 and an outlet of the first compressor stage 10; 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 configured to control the second speed of the second compressor stage 20 as a function of the first value P1. The data acquisition device 95 and the controller 96 can communicate with each other and can each communicate with components of the heat pump 100, as shown in . Fig 18 as indicated by the arrows pointing in opposite directions. The outlet of the first compressor stage 10 comprises an area immediately after the first compressor stage 10 as well as an area between the first compressor stage 10 and the second compressor stage 20, in particular an area in the steam channel 30.

[0088] Preferably, the value acquisition device 95 is configured to acquire a second value P2, which corresponds to or depends on a second pressure ratio between an outlet of the second compressor stage 20 and an inlet of the first compressor stage 10, and wherein the control device 96 is configured to further control the second speed depending on the second value P2. In particular, a region of the inlet of the second compressor stage 20 can connect to 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 sink 32 and the region of the inlet of the second compressor stage 20 can begin in the sink 32 of the steam channel 30 (see Fig. 18 ).

[0089] Fig. 18 Figure 1 shows the hydraulic diagram of heat pump 100, in which the first temperature sensor 91, the second temperature sensor 92 and the third temperature sensor 93 are shown. Figure 2 also shows... Fig. 18 The control unit 96 and the data acquisition unit 95 communicate with the individual components of the heat pump 100 and with each other. The cooling fluid 97 indicates the chilled water temperature that a user of the heat pump 100 receives as the actual temperature. The first temperature sensor 91 measures the first temperature Tl1 in the evaporator sump 52, and thus before the first compressor stage 10. The second temperature sensor 92 measures the second temperature Tl3 in the intercooler 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 Tl2 in the condenser sump 64, and thus after the second compressor stage. How Fig. 18 As indicated, a cooling capacity 103 is provided to the user, which serves as cooling capacity for customer water. This is capacity that is made available to the user or customer. The dissipated heat capacity 105 is heat capacity that is dissipated via a recooler. The motors M of the compressor stages 10 and 20 consume the electrical power 104, which is the power input of the heat pump 100, which is taken in by the two compressor stages 10 and 20. For example, a maximum pressure ratio of the first compressor stage 10 P1 = 3.7. For example, a maximum pressure ratio of the second compressor stage 20 P2 = 3.7. In this case, for example, the maximum total pressure ratio Ptotal of 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. When 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 1 (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 uniformly from P1 = P2 = 2.7 to P1 = P2 = 3.7.

[0090] Preferably, the control unit 96 is configured to use the first value P1 as the actual value and the second value P2 as the setpoint. Furthermore, the control unit 96 is preferably configured to increase the speed of the second compressor stage 20 when the actual value is greater than the setpoint, or to decrease the speed of the second compressor stage 20 when 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 and 20 can each be adjusted 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 and 20 is achieved by each having its own motor M of the compressor stages 10 and 20, which is driven separately. The first value P1 specifies a compression ratio of the first compressor stage 10 according to P1 = T13 / T11.The second value P2 indicates a compression ratio of the second compressor stage 20 according to P2=Tl2 / Tl3.

[0091] Preferably, the data acquisition device 95 is further configured to determine the actual temperature of a coolant 97 discharged from the evaporator, and the control unit 96 is configured to adjust the speed of the first compressor stage 10 depending on the actual temperature of the coolant 97 and a predefined setpoint temperature of the coolant 97. During operation of the heat pump 100, it can increase the actual temperature of the coolant 97 discharged from the evaporator, since the fluid circulating in the heat pump, i.e., the coolant 97, assumes a higher temperature over time due to the operation of the heat pump 100.Preferably, the control system is designed to operate the first compressor stage 10 with a higher pressure ratio than the second compressor stage 20, depending on a performance requirement in a first performance range 98, whereby the difference between the pressure ratios of the first compressor stage 10 and the second compressor stage 20 decreases as performance requirements increase (see Case 1 in . Fig. 19 ), and in order to operate both the first compressor stage 10 and the second compressor stage 20 in a second performance range 99 such that the pressure ratios of the two compressor stages 10, 20 in the second performance range 99 are approximately equal, or in particular equal within a range of plus / minus 20 percent, and / or increase equally with increasing performance demand (see case 2 in Fig. 19 ), wherein the second performance range 99 includes greater performance requirements than the first performance range 98, wherein a boundary 94 between the first performance range 98 and the second performance range 99 is defined by the first compressor stage 10 and / or by the second compressor stage 20. Fig. 19 Figure 1 shows a diagram illustrating the control of compressor stages 10 and 20 of heat pump 100 as a function of the rotational speeds of the first and second compression stages 10 and 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 output TT is achieved than in the first case, i.e., in the first power range 98 (cf. Figure 1). Fig. 19 ). The Fig. 19 It can further be deduced 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 power range 98, at which the first compressor stage is to be operated. The second compressor stage 20 starts with an initially lower power value TT, but increasingly approaches the setpoint of the first power stage 10. When the second compressor stage 20 also reaches the setpoint of power TT, both compressor stages 10 and 20 switch to an operating mode that 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 uniformly. At the boundary 94, the switch occurs from operation in the first power range 98 to operation in the second power range 99.In particular, at a total pressure ratio of p(TI2) / p(TII)), the heat pump 100 switches from operation in the first power range 98 to operation in the second power range 99, where p(TZI) indicates a saturated vapor pressure in the evaporator sump 52, which can be measured in particular by the first temperature sensor 91, and where p(TL2') indicates a saturated vapor pressure in the condenser sump 64, which can be measured in particular by the third temperature sensor 93 (cf. with . Fig. 18 ).

[0092] Preferably, the first compressor stage 10 and the second compressor stage 20 have radial impellers of different sizes, the control 96 being designed to control the first compressor stage 10 in the first performance range 98 to a constant first pressure ratio as a setpoint, and to control the second compressor stage 20 to an increasing second pressure ratio as a setpoint with increasing performance demand, and to accommodate an increasing performance demand in the second performance range 99 by both the first compressor stage 10 and the second compressor stage 20 (cf. mi Fig. 19 For example, the setpoint for the compressor stages 10 and 20 used is 2.7, as already explained. The setpoint may be different when using other compressor stages. 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 such that they both drive approximately the same mass flow rate. 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.

[0093] Preferably, the control unit 96 is configured to use as a setpoint for controlling the second speed of the second compressor stage 20 a maximum value derived from a function of the second value P2 or a predefined constant const. 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; the constant const = 2.7 is particularly advantageous. The constant is the optimal pressure ratio of the first compressor.

[0094] The maximum value of the second speed of the second compressor stage 20 is therefore given by: Maximalwert = P 2 oder konst .

[0095] The maximum value is given by a maximum function, which takes the highest value from the second value P2 or a predefined constant const. Preferably, the maximum function is a square root function and the predefined constant is the boundary 94 between the first and the second power ranges 98, 99. The maximum function is given in particular by drawings, see view "Original document", where p(TZI) indicates a saturated vapor pressure in the evaporator sump (52), which can be measured in particular by the first temperature sensor 91, and where p(TL2) indicates a saturated vapor pressure in the condenser sump 64, which can be measured in particular by the third temperature sensor 93 (cf. with Fig. 18 ).

[0096] The first value P1 is given by the ratio of: P1 = Tl3 / Tl1.

[0097] The second value P2 is given by the ratio of: P2 =TI2 / TI3.

[0098] A total compression ratio Ptotal, as it is in Fig. 19 The value shown is given by the product of the first value P1 and the second value P2, namely by: Pges = P 1 * P 2 = TI 3 / TI 1 * TI 2 / TI 3 = TI 2 / TI 1

[0099] For example, the Fig. 19 As can be seen, the first value P1 and the second value P2 are geometrically added (therefore 2* a / 2= a) to obtain the total compression ratio Ptotal.

[0100] Preferably, the value acquisition device 95 comprises a first temperature sensor for detecting a first temperature Tl1 with respect to the evaporator 50, and a second temperature sensor for detecting a second temperature Tl3 with respect to an output of the first compressor stage 10, wherein the value acquisition device 95 is configured to determine the first value P1 from the first temperature Tl1 and the second temperature Tl3. Fig. 18 For example, it shows where the temperature sensors could be located in the hydraulic diagram of the heat pump 100, indicating where each of the temperatures TU, Tl2 and Tl3 can be measured.

[0101] Preferably, the first temperature sensor is arranged in the evaporator sump 52 of the evaporator 50 to detect the first temperature Tl1 upstream of the first compressor stage 10, and the second temperature sensor is arranged in an intercooler sump 44 to detect the second temperature Tl3 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.

[0102] Preferably, a steam channel 30 is provided between the first compressor stage 10 and the second compressor stage 20 to guide the most compressed fluid from the first compressor stage 10 to the second compressor stage 20, wherein the intercooling sump 44 or the reservoir 45 is arranged in the steam channel 30. The first compressor stage 10 and the second compressor stage 20 are fluidically connected to each other via the steam channel 30.

[0103] Again Fig. 18 As can be seen, the data acquisition device 95 comprises a third temperature sensor for measuring a third temperature Tl2, wherein the data acquisition device 95 is configured to determine the second value P2 from the third temperature Tl2 and the first temperature (TI1). Preferably, the third temperature sensor is arranged in the condenser sump 64 to detect the third temperature Tl2 after the second compressor stage 20. Fig. 18 The diagram shows a hydraulic diagram highlighting temperature sensors for the control of the second compressor, specifically where the temperature sensors could be positioned in heat pump 100 to measure the respective temperature TU, Tl2, or Tl3. For example, as shown in... Fig. 8 As shown, the second temperature sensor can 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.

[0104] Preferably, the condenser sump 64 extends into the intercooling sump 44 ( Fig. 18 ) or into container 45 ( Fig 8 A fluid line 15 extends to convey fluid from the condenser sump 64 to the intercooler sump 44 or to the reservoir 45, and a further fluid line 15 extends from the intercooler sump 44 or reservoir 45 into the evaporator sump 52 to convey fluid from the intercooler sump 44 or reservoir 45 to the evaporator sump 52. Due to the connection of the sumps 64, 44, 45, and 52 via the fluid lines 15, the fluid level in each of the sumps 64, 44, 45, and 52 increases during operation of the heat pump 100. This can lead to a situation where, even during the operating time of the heat pump 100, the control of the compressor stages of the heat pump, as described in [reference missing], becomes problematic. Fig. 19 As shown, it requires.

[0105] 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-sectional reduction element 70 is arranged in the bypass channel 62 to adjust its cross-section and thus regulate the flow of compressed fluid from the first compressor stage 10 to the condenser 60. The cross-sectional reduction element 70 assumes a closed position when the second compressor stage 20 is operating. The bypass channel 62 and the cross-sectional reduction element 70 have already been described in detail, to which reference is made.

[0106] The speeds of compressor stages 10 and 20 can be increased for two reasons, as both the user side and the recooler side affect the heat pump. For example, the chilled water temperature 97 can rise. The water supplied to the user simply has a higher temperature, meaning the user requires more cooling capacity. In this case, the speed of the first compressor stage 10 is increased, thereby supplying more electrical power 104 to the heat pump 100. This increases the cooling capacity 103 generated by the heat pump. In another case, the chilled water temperature 97 can rise if the water temperature from the recooler to the condenser increases, for example, if the outside temperature rises and the recooler can only dissipate the heat energy with greater energy expenditure.In this case, for example, the measured temperatures TU, Tl3, and Tl2 rise, which ultimately increases the chilled water temperature supplied to the user. For the operation of compressor stages 10 and 20, this means that first the speed of the first compressor stage is increased, and then, with a slight delay, the speed of the second compressor stage is also increased. As the chilled water temperature rises, the electrical power consumption 104 of the heat pump 100 also increases.

[0107] The heat pump described herein allows the second compressor to be used more efficiently, thus increasing the overall efficiency of the heat pump. Furthermore, it prevents the second compressor stage from operating at its pumping or suction limits. 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 recooler. If the first compressor stage 10 provides the user with more cooling capacity, the additional heat is transferred to the recooler by the compressor stage 20, thereby increasing the electrical power consumption of the heat pump.

[0108] Another 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 area 66 and a holding area 67 for holding any vaporous fluid remaining after the condensation area 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 steam channel 30, which couples at least two of the N compressors of the N-stage compressor between the evaporator 50 and the condenser 60, and a steam guide line 92, which is 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, with the following steps: ; Evaporation of fluid through the evaporator 50; feeding of the evaporated fluid into the first compressor stage 10 to compress the evaporated fluid; guiding of the compressed fluid through the vapor channel 30 to pass the compressors; to finally reach the condenser 60; condensation of the compressed fluid in the condensation area 66 and retention of non-condensed fluid in the retention area 67; and return of the evaporated fluid via the vapor guide line 92 from the retention area 67 to the evaporator 50.

[0109] Another 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 area 66 and a holding area 67 for holding any vaporous fluid remaining after the condensation area 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 steam channel 30, which couples at least two of the N compressors of the N-stage compressor between the evaporator 50 and the condenser 60, and a steam guide line 92, which is 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, with the following steps: ; 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 connecting the evaporator and the condenser 60 via the steam guide line 92 to create a circuit in which the fluid circulates.

[0110] Another 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 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 passing the intercooling fluid from the container 45 through a heat exchanger 82 with a pipeline 56, wherein the pipeline 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.

[0111] Another 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, wherein the method comprises: 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;

[0112] Arranging a container 45 for collecting an intercooling fluid; and arranging a heat exchanger 82 with a pipeline 56 in a flow area 11 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 area 11.

[0113] Another 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 in the flow direction of the evaporated fluid in an operation of the heat pump 100 between the evaporator 50 and a condenser 60 and is configured 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 operating element 42, wherein the operating element 42 is arranged between the first compressor stage 10 and the second compressor stage 20, wherein the method comprises: Supply of intercooling fluid via the intercooling fluid supply line 3 from the evaporator sump 52 into the working element 42; output of a heated vaporous fluid through the first compressor stage 10; interaction of the intercooling fluid, which can be supplied via the intercooling fluid supply line 3, with the heated vaporous fluid output from the first compressor stage 10 in order to cool the vaporous fluid.

[0114] Another aspect concerns 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 in the flow direction of the evaporated fluid in an operation of the heat pump 100 between the evaporator 50 and a condenser 60 and is configured to compress the evaporated fluid to obtain compressed fluid; and the condenser 60 for condensing the compressed fluid; wherein the method comprises: arranging an intercooler 40 with an operating element 42 between the first compressor stage 10 and the second compressor stage 20

[0115] Connecting the intercooler 40 to an intercooling fluid supply line 3, which extends from the evaporator sump 52 to the operating element 42, in order to effect an interaction between an intercooling fluid, which 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 during operation of the heat pump 100.

[0116] Another aspect concerns a method for operating 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 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 compressed fluid; and a bypass channel 62 between the first compressor stage 10 and the condenser 60, wherein the method comprises: bypassing the second compressor stage 20 by adjusting a cross-section of a cross-sectional reduction element 70 in the bypass channel 62 to control a flow of compressed fluid from the first compressor stage 10 to the condenser 60.

[0117] Another aspect relates to a method for manufacturing 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 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 compressed fluid; wherein the method comprises: Arranging a bypass channel 62 between the first compressor stage 10 and the condenser 60 to bypass the second compressor stage 20, arranging a cross-sectional reduction element 70 in the bypass channel 62 to adjust the cross-section of the bypass channel 62 to regulate the flow of compressed fluid from the first compressor stage 10 to the condenser 60.

[0118] Another aspect concerns a method for operating a heat pump 100 with an evaporator 50 for evaporating a fluid to obtain an evaporated fluid; a condenser 60 for condensing a compressed fluid; and 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, comprising the following steps: sensing a first value P1 which corresponds to or depends on a first pressure ratio between an inlet of the first compressor stage and an outlet of the first compressor stage;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.;

[0119] Another aspect concerns 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 with a first compressor stage 10 and a second compressor stage 20, comprising the following steps: arranging the compressor in the flow direction of the evaporated fluid in a heat pump 100 operation between the evaporator 50 and the condenser 60 to compress the evaporated fluid to obtain the compressed fluid; and connecting a value sensing device to the compressor, the evaporator, or the condenser to detect a first value corresponding to, or dependent on, a first pressure ratio between an inlet of the first compressor stage and an outlet of the first compressor stage.and connecting a control unit to the compressor for 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.

[0120] As already mentioned in the general section, individual aspects described in relation to the heat pump can also be implemented as a process step.

[0121] Preferably, a method for manufacturing a heat pump 100, as described above, can be provided by producing the individual features and assembling them into one of the heat pumps 100 described above. The individual features will not be discussed again here in connection with the manufacturing process of the heat pump. Instead, reference is made to the above description of the individual features, which can also be understood as a process step for manufacturing.

[0122] Furthermore, a method for operating a heat pump 100 preferably comprises first providing a heat pump 100, as described above.

[0123] To operate the heat pump, at least one compressor stage 10, in particular the first, 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. Simultaneously, liquid fluid is supplied via the intercooling fluid supply line 3 to an active element 42 and / or a heat exchanger 82. Evaporated and compressed fluid leaving the first compressor stage 10 is cooled as described above. Furthermore, the method for operating a heat pump 100 includes adjusting the cross-section reduction element 70 to an open, closed, or intermediate position, as described above.Depending on the position of the cross-sectional reduction element 70, the evaporated and compressed fluid leaving the first compressor stage 10 is either routed directly to the condenser 60 via the bypass channel 62 (inactive vapor path) and / or via the vapor channel 30 to the second compressor stage 20 (active vapor path). In an intermediate position of the cross-sectional reduction element 70, both the inactive and active vapor paths can be used to route the evaporated and compressed fluid. A description of the fluid circulation is already provided above and will not be repeated in connection with the heat pump operating procedure to avoid redundancy. Instead, reference is made to the above description, which can also be understood as the process steps for operating the heat pump.In particular, the various described characteristics can be combined or interchanged as desired. Specifically, "fluid" and "cooling water" are used synonymously. Specifically, the term "steam" refers to vaporized fluid. Reference symbol list

[0124] 1 further return line 3 Intercooler fluid supply line 2 return line 4 further intercooler 5 yet another intercooler 7 packing material 8 indirect intercooling 10 first compressor stage 11 flow area 12 intake port 14 guide chamber 15 fluid line channel 16 maximum diameter 17 minimum diameter 20 second compressor stage 22 circulation pump 30 vapor channel (banana) 32 sink 33 motor cooling line 34 motor cooling 35 further motor cooling line 36 further motor cooling 40 intercooler 42 working element 44 intercooler sump 45 reservoir 46 first intercooler line 48 second intercooler line 49 ball bearing adapter 50 evaporator 51 fluid level 52 evaporator sump 54 upper evaporator section 55 opening into the evaporator 56 piping 56a tube bundle 56b spiral tube arrangement 57 Irrigation area 58 Irrigation device 59 First evaporator line 60 Condenser 62 Bypass channel 64 Condenser sump 65 Opening of a line ina sump 66 condensation area 67 holding area 68 fill level 70 cross-sectional reduction element 72 diameter of the cross-sectional reduction element 74 ball bearing adapter line 76 ball bearing adapter 77 compressor cooling duct 80 Nth compressor stage 82 heat exchanger 83 winding 90 vapor transfer damper / bypass damper 92 vapor supply line 91 first temperature sensor 92 second temperature sensor 93 third temperature sensor 94 limit 95 value acquisition device 96 control 97 actual temperature of a coolant discharged on the evaporator side 98 first line range 99 second capacity range Tl1 first temperature Tl3 second temperature Tl2 third temperature 100 heat pump 101 helix 102 helix axis 103 cooling capacity 104 electrical power 105 dissipated power 170 compressor characteristic curve / limit lines 171 surge limit 172 dotted lines 180 Enclosure surface 181 Speed ​​characteristic curve P1 first value / actual value P2 second value / target value M Motor 300 Test stand 301 to be testedCompressor 302 Pressure sensor 303 Temperature sensor 304 Steam flow 306 Pipe 307 Throttle valve 308 Return 309 Sensor 310 Pump 311 Connection 2' Evaporator 3' First compressor 4' Intercooler 4a' Intercooler sump 4c' Pump 5' Second compressor 6' Condenser 41 ' Tank 71 ' Supply line 72' Supply line V0 Steam bypass 50' Evaporator 60' Condenser

Claims

1. Heat pump (100) having the following features: an evaporator (50) for evaporating a fluid, in order to obtain evaporated fluid, wherein the evaporator (50) comprises an evaporator sump (52); a compressor having a first compressor stage (10) and a second compressor stage (20), wherein the compressor is arranged in the flow direction of the evaporated fluid, during operation of the heat pump (100), between the evaporator (50) and a condenser (60), and is configured to compress the evaporated fluid, in order to obtain compressed fluid, wherein the condenser (60) is provided for condensing the compressed fluid; and an intermediate cooler (40), which is connected to an intermediate cooling fluid feeding line (3) and comprises an effect element (42), wherein the effect element (42) is arranged between the first compressor stage (10) and the second compressor stage (20) and is configured to bring about an interaction between an intermediate cooling fluid which can be supplied via the intermediate cooling fluid feeding line (3), and a heated vaporous fluid that can be discharged from the first compressor stage (10), and wherein the intermediate cooling fluid feeding line (3) extends from the evaporator sump (52) to the effect element (42), characterized in that a ball bearing adapter line (74) is arranged from the intermediate cooling sump (44) to a ball bearing adapter (76) which is assigned to the first compressor stage (10), in order to conduct fluid out of the intermediate cooling sump (44) for cooling the ball bearing adapter (76), and wherein 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 out of the ball bearing adapter (76) to the first compressor stage (10), in order to sprinkle compressed fluid in the first compressor stage (10) with the fluid from the ball bearing adapter (76).

2. Heat pump (100) according to claim 1, wherein the intermediate cooling fluid feeding line (3) extends through an opening (55) in the evaporator sump (52), and wherein the opening (55) of the intermediate cooling fluid feeding line (3) is located below a fluid level (51) of the fluid in the evaporator sump (52).

3. Heat pump (100) according to either claim 1 or claim 2, wherein the intermediate cooler (40) comprises an intermediate cooling sump (44), wherein proceeding from a base of the intermediate cooling sump (44) a return line (2) for returning fluid from the intermediate cooling sump (44) into the evaporator sump (52) extends into the evaporator sump (52), preferably laterally, in particular wherein the heated vaporous fluid that can be discharged from the first compressor stage (10), and the intermediate cooling fluid, are in each case withdrawn from the evaporator sump (52).

4. Heat pump (100) according to any one of claims 1 to 3, wherein a further return line (1) for returning fluid out of the condenser sump (64) into the evaporator sump (52) extends from the condenser sump (64) directly into the evaporator sump (52), preferably laterally, in particular, wherein the return line (2) and the further return line (1) are fluidically separated from one another.

5. Heat pump (100) according to any one of claims 1 to 4, wherein the intermediate cooling fluid feeding line (3) is furthermore connected to at least one further intermediate cooler (4), wherein the further intermediate cooler (4) is arranged in a vapour duct (30) between the evaporator (50) and the condenser (60), in particular, wherein the further intermediate cooler (4) is arranged after an outlet of the first compressor stage (10).

6. Heat pump (100) according to any one of claims 3 to 5, wherein the intermediate cooling sump (44) is configured for collecting fluid that can flow through the intermediate cooling fluid feeding line (3), wherein the fluid can be supplied from the intermediate cooling sump (44) to the evaporator sump (52) via the return line (2), in particular, wherein the return line (2) and the further return line (1) each comprise an opening (55) to the evaporator sump (52) at spaced positions of the evaporator sump (52).

7. Heat pump (100) according to any one of the preceding claims, wherein the intermediate cooling fluid feeding line (3) or a motor cooling line (33) is arranged from the evaporator sump (52) to a motor cooling stage (34) of the first compressor stage (10), in order to conduct fluid out of the evaporator sump (52) to the motor cooling stage (34) for cooling a motor (M) assigned to one of the first compressor stage (10), in particular, wherein the intermediate cooling fluid feeding line (3) or the motor cooling line (34) extends from the evaporator sump (52) via the motor cooling (34) of the first compressor stage (10) to the effect element (42), in order to conduct fluid out of the evaporator sump (52) to the motor cooling (34), for cooling the motor (M) assigned to the first compressor stage (10), and to the effect element (42).

8. Heat pump (100) according to any one of the preceding claims, wherein a further motor cooling line (35) is arranged from the evaporator sump (52) to a further motor cooling stage (36) of the second compressor stage (20), in order to conduct fluid out of the evaporator sump (52) to the further motor cooling stage (36) for cooling a motor (M) assigned to one of the second compressor stage (20).

9. Heat pump (100) according to any one of the preceding claims, wherein at least one filling material (7) for discharging heat is arranged in a region around the first compressor stage (10).

10. Heat pump (100) according to any one of the preceding claims in combination with claim 5, wherein a still further intermediate cooler (5) is arranged in the intermediate cooling fluid feeding line (3), in particular, wherein, due to the arrangement of the intermediate cooler (40), the further intermediate cooler (4) and the still further intermediate cooler (5), the vapour in the intermediate cooling fluid feeding line (3) passes, after emerging from the first compressor stage (10), first through the further intermediate cooler (4) and subsequently through the still further intermediate cooler (5) and / or the intermediate cooler (40).

11. Heat pump (100) according to claim 5 or 10, wherein the further intermediate cooler (4) is configured as a heat exchanger (82) which is configured as a pipeline (56) and / or as a pipe bundle (56a) and has a pipe volume through which fluid from the evaporator sump (52) flows, in order to allow for indirect cooling of the vapour.