The present invention relates to the field of heat pumps, and in particular to concepts for improving the efficiency of a heat pump.
EP 3 203 164 describes a heat pump.
In the publication Novel Turbo Compressor for Heat Pump Using Water as Refrigerant and Lubricant, by T. Shoyama et al. 2019, IOP Conf.: Mater. Sci. Eng. 604011010, a compressor for a heat pump comprising a vapour bypass V0 is described, which taps off the vapour directly after the compressor (see
Typically the power consumption of the first compressor stage is used as a reference variable for the second compressor stage. This results in that the two compressor stages (first and second compressor stage) contribute a similar pressure ratio to the overall pressure ratio, since both rotate at approximately the same speed. As a result, the flow through the second compressor is not optimal. This is particularly problematic in the case of high pressure ratios, because on account of the ambient temperature and the control of the second compressor by the power consumption of the first compressor, a variety of vapour volume flows results. The liquefaction and re-evaporation in the intermediate circuit leads to a thermodynamic loss, such that the pressure ratios of the compressor stages do not fully contribute to the overall compression ratio. This is a problem in particular for the second compressor.
The object of the present invention consists in providing an improved heat pump which in particular has an improved design for heat exchange of a fluid circulating in the heat pump, such as a cooling fluid.
This object is achieved by a heat pump according to claim 1.
The heat pump according to the present invention comprises an evaporator for evaporating a fluid in order to obtain an evaporated fluid, wherein the evaporator has an evaporator sump, and a condenser for condensing a compressed fluid, wherein the condenser has a condenser sump. Furthermore, the heat pump comprises a compressor having a first compressor stage and a second compressor stage, wherein the compressor is arranged in the flow direction of the evaporated fluid, during operation of the heat pump, between the evaporator and the condenser, and is configured to compress the evaporated fluid in order to obtain the compressed fluid; a container for collecting an intermediate cooling fluid; and a heat exchanger having a pipeline, which is configured for the intermediate cooling fluid to flow through from the container, wherein the pipeline is arranged in a flow region between the first compressor stage and the second compressor stage, in order to cool vaporous fluid in the flow region.
Of course, individual aspects which are described with reference to the heat pump can also be implemented as method steps, and vice versa. Further details are discussed in the context of the following description of the drawings.
Preferred embodiments of the present invention are explained in detail in the following with reference to the accompanying drawings, in which show:
Individual aspects of the invention described herein are described in the following in
The heat pump 100 according to the invention is described in overview of the accompanying
The hydraulic diagram according to
The hydraulic diagram according to
Further features of the hydraulic diagram according to
According to a preferred embodiment, the heat pump 100 comprises the evaporator 50 for evaporating a fluid in order to obtain an evaporated fluid, wherein the evaporator 50 comprises the evaporator sump 52. The heat pump 100 further comprises the condenser 60, in order to condense evaporated fluid compressed by an N-stage compressor 10, 80, 20, wherein the condenser 60 has a condenser sump 64, a condensation region 66 and a holding region 67 for holding a vaporous fluid still remaining after the condensation region 66. The N-stage compressor 10, 20, 80 comprises N compressors, wherein N is a natural number greater than or equal to one, wherein the N-stage compressor 10, 20, 80 is arranged between the evaporator 50 and the condenser 60. The heat pump 100 furthermore comprises the vapour duct 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.
The holding region 67 comprising condensed working fluid is preferably arranged in the condenser 60 between the condensation region 66 and the condenser sump 64. An opening 65 of the vapour-conducting line 92 is arranged in the holding region 67 above a filling level 68, in particular a fluid level 51, of the working fluid in the condenser sump 64. The opening 65 of the vapour-conducting line 92 comprises a channel piece which protrudes through the condenser sump 64 into the holding region 67, in order to conduct evaporated, i.e. non-condensed, fluid via the vapour-conducting line 92 to the evaporator 50.
The condenser sump 64 comprising condensed working fluid is preferably arranged in the condenser 60. The vapour-conducting line 92 extends from the holding region 67 through the condenser sump 64 and is conducted out of the condenser through a wall, preferably a base, of the condenser 60.
The condenser 60 preferably comprises a pipe bundle 56a or a helical pipe arrangement 56b, through which liquid to be heated can flow, wherein the pipe bundle 56a or the helical pipe arrangement 56b is arranged laterally with respect to the opening 65 of the vapour-conducting line 92, and wherein an suction manifold 12 of a compressor of the N-stage compressor 10, 20, 80 is arranged above the pipe bundle 56a or the helical pipe arrangement 56b. In the present case, the pipe bundle 56a or the helical pipe arrangement 56b are also referred to as a pipeline 56.
The vapour-conducting line 92 preferably comprises an opening 55 into the evaporator 50 wherein the opening 65 is arranged above the evaporator sump 52, in the evaporator 50. The vapour-conducting line 92 thus comprises two openings 55, 65, wherein one opening leads through the condenser sump 64 and the other opening 55 leads into the evaporator 50 above the evaporator sump 52. This can be derived for example from
Preferably a pipe bundle 56a for liquid to be cooled, and a sprinkling device 58 for sprinkling the pipe bundle 56a, are arranged in the evaporator 50, wherein the opening 55 of the vapour-conducting line into the evaporator 50 is arranged such that vaporous fluid which enter the evaporator 50 through the opening 55 strikes the pipe bundle 56a laterally, and/or that the vaporous fluid which emerges from the vapour-conducting line 92 enters a sprinkling region 57 which is sprinkled at least in part by the sprinkling device 58. As can be seen for example from
Preferably, each compressor of the N-stage compressor 10, 20, 80 comprises its own shaft, on which the corresponding compressor of the N-stage compressor 10, 20, 80 can be operated and individually actuated during operation. As can be seen for example from
The N-stage compressor 10, 20, 80 preferably comprises N compressors connected in series, wherein the vapour-conducting line 92 is configured as a single vapour-conducting line 92 and conducts the vaporous fluid, brought into the condenser 60 from a last stage, from the condenser 60 into the evaporator 50 (see
Preferably, at least two compressors of the N-stage compressor 10, 20, 80 are connected via a vapour duct 30 and in each case an intermediate cooler 40 is arranged between two compressors, in order to cool the vaporous fluid (see
The intermediate cooler 40 is preferably arranged in a sink 32 of the vapour duct 32 and the intermediate cooler 40 comprises an intermediate cooling sump 44 and an effect element 42, wherein the effect element 42 is configured to bring about an interaction between an intermediate cooling fluid that can flow through a supply line, in particular the first intermediate cooler line 46, from the intermediate cooling sump 44 or from the evaporator sump 52 or from the condenser sump 64 into the effect element 42, and a heated vaporous fluid that can be output from the compressor, wherein the interaction in particular brings about cooling of the vaporous fluid, discharged from the compressor, by the intermediate cooling fluid (see
Preferably, each intermediate cooler 40 comprises an intermediate cooling sump 44 and an effect element 42 and is arranged in its own sink 32 in the vapour duct 30, in particular each intermediate cooler 40 comprises its own first intermediate cooler line 46 to the effect element 42. The first intermediate cooler line 46 can also be referred to as a supply line. In particular in the case of a plurality of intermediate cooling sumps 44, the supply lines, i.e. the first intermediate cooler lines 46, can also be connected to one another (not shown in the figures), such that the supply lines then form just one supply line overall.
The vapour duct 30 preferably has a curved shape, comprising the sink 32, between two compressors, such that fluid from the vapour duct 30 flows past the intermediate cooling sump 44. Condensed fluid can be collected in the intermediate cooling sump 44.
Preferably, the vapour-conducting line 92 and the vapour duct 30 are fluidically separated from one another. In the present case, fluidically separated from one another means that the vapour-conducting line 92 and the vapour duct 30 do not merge into one another, which would allow mixing of the fluid. Therefore, the vapour-conducting line 92 and the vapour duct 30 are shown for example by dashed lines in
Preferably, further N compressors are arranged such that a further compressor of the N compressors is connected in series with a first compressor of the N-stage compressor 10, 20, 80, by switching a switch into an open state. In
A bridging flap 90 is preferably arranged in the vapour-conducting line 92, which flap can be transferred into an open position for conducting the vaporous fluid from the condenser 60 to the evaporator 50, an intermediate position, or into a closed position for preventing conduction of the vaporous fluid into the evaporator. Similarly to the cross-section reducing element 70, the bridging flap 90 can be configured as a orifice or a leaf door or a check valve, or as a valve as is shown for example in
The bridging flap 90 is preferably configured as a controlled bridging valve which can be addressed by means of the controller in order to be operated close to a boundary line of a compressor characteristic diagram 170 assigned to the N-stage compressor 10, 20, 80. The configuration of the bridging flap 90 as a controlled bridging valve is shown for example in
A compressor characteristic diagram 170 assigned to the N-stage compressor 10, 20, 80 defines a relationship between a pressure ratio and a mass flow. A compressor characteristic diagram 170 of this kind is shown for example in
The controller is preferably configured to transfer the bridging flap 90 into a closed position, into an open position, or into an intermediate position, in order to hold a load of the N-stage compressor 10, 20, 80 at least at a load target value, during operation. The pump limit 171 can in particular describe the load target value, which can in particular also be a function depending on the mass flow WcCorr. In particular, the controller is configured to actuate the bridging flap 90 in such a way that operation of the heat pump 100 takes place substantially along the pump limit 171 or in a region shifted slightly to larger mass flows WcCorr, such that operation of the compressor below its absorption limit is advantageously prevented.
The controller is preferably configured to open the bridging flap 90 if the load of the N-stage compressor 10, 20, 80 falls below the load target value; or to close the bridging flap 90 if the load of the N-stage compressor 10, 20, 80 exceeds the load target value, in order to create an additional load; or to control the intermediate position of the bridging flap 90 depending on falling below the load target value. This makes it possible for the heat pump to be operated substantially along the pump limit 171. For example, the bridging flap 90 can be transferred into the intermediate position if the load of the N-stage compressor 10, 20, 80 deviates from the load target value by up to 5%. This can take place beginning from the open or from the closed position of the bridging flap 90. The load target value specifies a load of the heat pump 100 during operation, which is to be achieved at least by the N-stage compressor 10, 20, 80.
Preferably, in the case of a two-stage compressor 10, 20, as is shown for example in
A preferred embodiment of the heat pump 100 comprises an evaporator 50 for evaporating a fluid in order to obtain evaporated fluid. The heat pump 100 further comprises a condenser 60 for condensing a compressed fluid. Furthermore, the heat pump 100 comprises 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 the condenser 60, and is configured to compress the evaporated fluid in order to obtain compressed fluid. It is proposed for a bridging channel 62 to be arranged between the first compressor stage 10 and the condenser 60, in order to bridge the second compressor stage 20, wherein a cross-section reducing element 70 is arranged in the bridging channel 62 in order to set a cross-section of the bridging channel 62 for controlling a through-flow of compressed fluid out of the first compressor stage 10 to the condenser 60. After exiting the first compressor stage 100, compressed fluid can thus be conducted directly to the condenser 60, provided that the cross-section reducing element 70 assumes an open position. In particular when the second compressor stage 20 is not in operation, i.e. is in a deactivated state, the cross-section reducing element 70 is in the open position.
The first compressor stage 10 and the second compressor stage 20 are preferably connected via the vapour duct 30 (see also description relating to
The bridging channel 62 preferably comprises an opening into the first compressor stage 10, wherein the first compressor stage 10 comprises an suction manifold 12 for suctioning the evaporated fluid, and a conducting chamber 14 for conducting the vaporous compressed fluid into the bridging channel 62. The suction manifold 12 can be cone-shaped, wherein a first diameter is arranged in a suction region of the suction manifold 12 for suctioning the fluid, and a second diameter of the suction manifold 12 directly adjoins the conducting chamber 14. In particular, the first diameter is larger than the second diameter. In the present case, the first diameter is a maximum diameter 16 and the second diameter is a minimum diameter 17. The conducting chamber 14 is arranged transversely, in particular substantially orthogonally, to the second diameter of the suction manifold 12.
The condenser 60 preferably comprises a pipeline 56. The pipeline 56 is preferably configured as a pipe bundle 56a or a helical pipe arrangement 56b, through which liquid to be heated can flow, wherein the pipe bundle 56a or the helical pipe arrangement 56b is arranged laterally with respect to a further opening of the bridging channel 62, and wherein a suction manifold 12 of a compressor of the second compressor stage 20 is arranged above the pipe bundle 56a or the helical pipe arrangement 56b.
The further opening of the bridging channel 62 is preferably arranged such that vaporous fluid which enters the condenser 60 through the further opening strikes the pipe bundle 56 laterally. Since the pipeline 56, i.e. the pipe bundle 56a or the helical pipe arrangement 56b, is arranged laterally with respect to a further opening of the bridging channel 62, in the condenser 60, evaporated compressed fluid, after passing through the bridging channel 62, directly strikes the pipeline 56, at which the evaporated and compressed fluid can be cooled. Since fluid to be heated can flow through the pipeline 56, a heat transfer occurs from the evaporated and compressed fluid, which strikes the pipeline 56 laterally from the bridging channel 62, via the pipeline 56, to the fluid to be heated which flows through the pipeline. When the evaporated and compressed fluid strikes the pipeline 56, the evaporated and compressed fluid is cooled, such that condensation may occur. A fluid condensed on the pipeline 56 may, in particular due to gravity, drip into the condenser sump 64.
The cross-section reducing element 70 is preferably configured to assume a closed position or an open position, depending on the operation of the second compressor stage 20, wherein the cross-section reducing element 70 is configured to assume the closed position when the second compressor stage 20 is activated, or to assume the open position when the second compressor stage 20 is deactivated. Depending on the operation of the second compressor stage 20, the cross-section reducing element 70 can be transferred into the closed or the open position. It is furthermore conceivable to transfer the cross-section reducing element 70 into an intermediate position, i.e. a position between the open and the closed position, in particular then, when the second compressor stage 20 is shut down (deactivated) or started up (activated).
The cross-section reducing element 70 is preferably pretensioned by means of a spring element (not shown) in the closed position. If the second compressor stage 20 is deactivated, the pretensioned spring element can relax, in particular due to failure of suctioning of compressed fluid of the first compressor stage 10 through the vapour duct 30, such that the cross-section reducing element 70 transitions into the open position. The compressed fluid from the first compressor stage 10 can thereupon pass through the bridging channel 62, as a result of which the second compressor stage 20 is bridged.
The cross-section reducing element 70 is preferably a flap or an orifice or a leaf door or a check valve.
The heat pump 100 preferably comprises a controller for controlling the cross-section reducing element 70 into the open position or the closed position. Depending on the configuration of the cross-section reducing element 70 as a flap or orifice or leaf door or check valve, the controller is configured to actuate the flap or orifice or leaf door or check valve. In the configuration as a orifice, for example, the controller is configured to increase or reduce a diameter of the orifice.
Preferably, the first compressor stage 10 is configured to build up a maximum achievable pressure, and the cross-section reducing element 70 is configured to assume the open position when a pressure ratio between the condenser pressure TI2 and the evaporator pressure TI1 is smaller than the maximum achievable pressure of the first compressor stage, in order to conduct compressed fluid out of the first compressor stage 10, via the bridging channel 62, to the condenser 60. The pressure ratio between the condenser pressure TI2 and the evaporator pressure TI1 can be calculated for example by measuring temperatures. In particular, the temperature TI1 in the evaporator sump 52 and the temperature TI2 in the condenser sump 64 can be measured in each case, in order to determine therefrom the pressure ratio between the condenser pressure (TI2) and the evaporator pressure TI1. In the present case, the measured temperature TI1 in the evaporator sump 52 is associated with the evaporator pressure TI1. In the present case, furthermore the measured temperature TI2 in the condenser sump 64 is associated with the condenser pressure TI2. Therefore, the corresponding measured temperature reference signs TI1 and TI2 are used for the respective pressure in the condenser sump 64 and respectively in the evaporator sump 52.
Preferably, the cross-section reducing element 70 is configured to assume the closed position when the pressure ratio between the condenser pressure TI2 and the evaporator pressure TI1 is greater than the maximum achievable pressure of the first compressor stage 10, in order to conduct compressed fluid out of the first compressor stage 10, via the vapour duct 30, to the second compressor stage 20. Having arrived in the second compressor stage 20, the compressed fluid is compressed further, before it is supplied to the condenser 60 via a conducting chamber 14. The conducting chamber 14, which is assigned to the condenser 60, is configured analogously to the conducting chamber 14, which is assigned to the evaporator 50 in the upper evaporator upper part 54.
The first compressor stage 10 is preferably operable with N further compressor stages, wherein N is a natural number greater than or equal to two.
In the preferred embodiment of the heat pump 100, as is shown in
The pipeline 56 is preferably made of metal; the pipeline 56 preferably comprises stainless steel and/or copper. The metal pipeline 56 improves a heat transfer between fluid inside the pipeline 56 and fluid outside the pipeline 56.
The pipeline 56 of the heat exchanger 82 is shown for example in
The first compressor stage 10 preferably comprises an suction manifold 12 for suctioning the evaporated fluid, and a conducting chamber 14 for conducting the vaporous fluid into the flow region 11. The flow region 11 has a volume of an upper evaporator part 54, the vapour duct 30, and also the bridging channel 62. The flow region 11 comprises those regions of the heat pump 100 into which evaporated and compressed fluid can flow.
As is shown for example in
Preferably, a vapour duct 30 is arranged between the pipeline 56 and the container 45, wherein the outflow region 11, in particular which is also referred to as the flow region 11, is connected to the vapour duct 30, in order to conduct the vaporous fluid throughout through the container 45 via the vapour duct 30; “conduct throughout through the container 45” is to be understood as “conduct beyond the container 45 away”. The vaporous fluid is pulled in through the second compressor during operation of the second compressor stage 20. As a result, the vaporous fluid is conducted through the vapour duct 30, as can be seen for example, from
A fluid conducting channel 15 preferably extends from the outflow region 11 laterally into the vapour duct 30, in order to supply the intermediate cooling fluid flowing through the heat exchanger 82 to the container 45, via the vapour duct 30 (see
The suction manifold 12 is preferably funnel-shaped, having a maximum diameter 16 and a minimum diameter 17 opposite one another, wherein the conducting chamber 14 for conducting the compressed vaporous fluid extends axially to the minimum diameter 17 of the funnel shape. The maximum diameter 16 can adjoin the base of the upper evaporator part 54, as a result of which the intermediate cooling fluid flowing through the heat exchanger 82 is collected outside the suction manifold 12 of the first compressor stage 10, in the base region (see
The conducting chamber 14 is designed preferably curved at an end which transitions into the upper evaporator part 54, in order to conduct the vaporous fluid, flowing through the conducting chamber 14, in a direction counter to a gas flow direction in the suction manifold. In particular, the vaporous fluid leaving the conducting chamber 14 is conducted into the vapour duct 30 if the second compressor stage is in operation, or into the vapour-conducting line 92 if the second compressor stage is not in operation.
The conducting chamber 14 preferably has a volume having a circle or an oval as a footprint. The conducting chamber 14 is arranged substantially perpendicularly to the minimum diameter 16 of the suction manifold 12 of the first compressor stage 10. The conducting chamber is in particular arranged in the upper evaporator part 54. The second compressor stage 20 furthermore also comprises a conducting chamber 14 which is arranged substantially perpendicularly to the minimum diameter 16 of the suction manifold 12 of the second compressor stage 20. The conducting chamber 14 of the first or the second compressor stage 10, 20 may also have any other configuration of footprint.
A further heat exchanger 82 is preferably arranged in the vapour duct 30 spaced apart from the outflow region 11. The further heat exchanger 82 is preferably arranged in an suction manifold 12 of the second compressor stage 20. The first and the second compressor stage 10, 20 are connected via the vapour duct 30, wherein the vapour duct 30 is arranged between a pressure side of the first compressor stage 10 and a suction side of the second compressor stage 20. The vapour duct 30 preferably has a curved shape having a sink 32. The container 45 is preferably arranged in the sink 32, such that liquid intermediate cooling fluid flows out of the vapour duct 30 and into the container 45. This can be seen for example, from
The heat exchanger 82 and/or the further heat exchanger 82 preferably comprises/comprise, on its/their outer surface, an outer surface that is contoured at least in part, which is in contact with the vaporous fluid, in order to improve a heat transfer between the heat exchanger 82 and the vaporous fluid. The heat exchanger 82 and/or the further heat exchanger 82 preferably comprises/comprise, on its/their inner surface, an inner surface that is contoured at least in part, which is in contact with the fluid from the container 45, in order to bring about the configuration of a turbulent flow on their inner surface. The contoured inner and/or outer surfaces can comprise grooves and/or reliefs, i.e. recesses/elevations of any desired shape.
Preferably, for self-regulation of a fluid filling level, the condenser sump 64 and/or the evaporator sump 52 and/or the container 45 is/are in each case interconnected via a fluid conducting channel 15 in a fluidically conducting manner, such that the fluid level 51 of the individual sumps 52, 45, 64 is controlled, in particular only using gravity. In other words, the fluid level 51 of the individual sumps 52, 45, 64 is set passively on account of the geometric arrangement and the interconnection of the individual sumps 52, 45, 64 (see, for example
A return line 2, which is in particular also referred to as a fluid conducting channel 15, for conducting fluid out of the condenser sump 64, preferably extends from the condenser sump 64 into the container 45 or the intermediate cooling sump 44. Further preferably, a fluid conducting channel 15 for conducting fluid out of the container 45 or the intermediate cooling sump 44 extends from the container 45 or the intermediate cooling sump 44, respectively, into the evaporator sump 52, wherein, in particular the fluid conducting channel 15 extends laterally into the evaporator sump 52 under the fluid level 51 of the evaporator sump 52, beginning from a base of the container 45 or of the intermediate cooling sump 44. The container 45 is preferably an intermediate cooling sump 44 of an intermediate cooler 40.
The heat pump 100 preferably comprises an intermediate cooling recirculation pump 22, in order to supply intermediate cooling fluid from the container 45 to the pipeline 56. In this embodiment of the heat pump 100, the intermediate cooling fluid feed line 3 can extend from the container 45 to the pipeline 56 (see
According to a further preferred embodiment, the heat pump 100 comprises the evaporator 50 for evaporating a fluid in order to obtain an evaporated fluid, wherein the evaporator 50 comprises the evaporator sump 52. The heat pump 100 further comprises the compressor having the first compressor stage 10 and the 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 the condenser 60, and is configured to compress the evaporated fluid in order to obtain compressed fluid. The condenser 60 serves for condensing the compressed fluid. Furthermore, the heat pump 100 comprises the intermediate cooler 40, which is connected to an intermediate cooling fluid feed line 3, and the effect element 42, wherein the effect element 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 feed line 3, and a heated vaporous fluid that can be discharged from the first compressor stage 10. The intermediate cooling fluid feed line 3 extends from the evaporator sump 52 to the effect element 42. Such a preferred embodiment of the heat pump is shown as a hydraulic diagram in
The intermediate cooling fluid feed line 3 preferably extends through an opening in the evaporator sump 52, and wherein the opening of the intermediate cooling fluid feed line 3 is 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 intermediate cooling fluid feed line 3, in particular making use of gravity. In particular, the intermediate cooling fluid feed line 3 does not require a controller for supplying fluid from the evaporator sump 52. It is conceivable, however, to provide a controller for supplying the intermediate cooling fluid feed line 3 with liquid fluid.
As shown in
A further return line 1, which can be, in particular, also referred to as a fluid conducting channel 15, for returning fluid out of the condenser sump 64 into the evaporator sump 52, preferably extends from the condenser sump 64 directly into the evaporator sump 52, preferably laterally. In particular the return line 2 and the further return line 1 are fluidically separated from one another. “Fluidically separated from one another” means that the fluid from the return line 2 and the further return line 1 cannot mix in a line, but are mixed together first in the evaporator sump 52. With respect to the lines 1, 2 and 3,
According to the further preferred embodiment of the heat pump as shown in
As shown in the embodiments according to
The intermediate cooling fluid feed line 3 or a motor cooling line 33 is preferably 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 the first compressor stage 10. In particular, the intermediate cooling fluid feed line 3 and/or the motor cooling line 33 extends/extend from the evaporator sump 52 via the motor cooling stage 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 stage 34 for cooling a motor M assigned to the first compressor stage 10, and to the effect element 42 (see
As can further be seen from
As can be seen for example in
Further 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 conduct fluid out of the condenser sump 64 for cooling the at least one ball bearing adapter 76. In particular, a compressor cooling channel 77 is arranged from an outlet of the ball bearing adapter 76 to the second compressor stage 20, in order to conduct fluid out of said ball bearing adapter 76 to the second compressor stage 20, in order to sprinkle 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 that is not shown, the ball bearing adapter can also receive fluid for cooling from the intermediate cooling fluid feed line 3 and thus be connected, in series or in parallel, to the same line to which the motor cooling stage 36 is also connected.
Preferably, at least one filling material 7 for discharging heat, in particular for enlarging the surface and thus for optimised cooling of the vapour, is arranged in a region around the first compressor stage 10. The at least one filling material 7 is arranged, in particular around the suction manifold 12 of the first compressor stage 10 (compare with
As can be seen for example from
The further intermediate cooler 4 is preferably 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 8 of the vapour.
Preferably, the second compressor stage 20 is arranged between the evaporator 50 and the condenser 60, and the intermediate cooler 40, the further intermediate cooler 4 and/or the still further intermediate cooler 5 are arranged at a spacing from a suction region of the second compressor stage 20. As can be seen, for example in
In order to regulate a fluid filling level, i.e. a fluid level 51, the condenser sump 64 and/or the evaporator sump 52 and/or the intermediate cooling sump 44 can each comprise level control. A level control can preferably be omitted, provided that the fluid level 51 in the individual sumps 52, 44, 64 controls itself by way of the level of the outflows, i.e. provided that self-regulation, as already described, is possible. The fluid level 51 then does not need to be actively controlled. In the present case, outflows means, for example the opening 65 of the vapour-conducting line 92 into the condenser 60, and/or the opening 65 of the return line 2 into the intermediate cooling sump 44, and/or the opening 65 of the intermediate cooling fluid feed line 3 into the evaporator sump 52, as is shown for example in
As already explained,
The volume flow cannot be measured directly. Said flow is instead determined indirectly via a stored 3D characteristic diagram 190 which is specific for a compressor drive used. The volume flow is derived in the 3D characteristic diagram 190 depending on the drawn electrical power Pei and the rotational speed of the compressor drive, with the aid of the 3D characteristic diagram in the 3D characteristic diagram 190 (see dotted curves 191), in that the measured values 191 are plotted in the 3D characteristic diagram 190. After the volume flow has been determined, the mass flow can be corrected, in particular by applying knowledge of the molar mass of the fluid at a given pressure and a given temperature.
According to a preferred embodiment, the heat pump 100 comprises the evaporator 50 for evaporating a fluid in order to obtain an evaporated fluid; the condenser 60 for condensing a compressed fluid; and the 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 the condenser 60, and is configured to compress the evaporated fluid, in order to obtain the compressed fluid. Furthermore, the heat pump 100 comprises a value acquisition device 95 for acquiring a first value P1, which corresponds to a first pressure ratio between an inlet of the first compressor stage 10 and an outlet of the first compressor stage 10, or is dependent on the first pressure ratio; and a controller 96 for controlling a first rotational speed of the first compressor stage 10 and a second rotational speed of the second compressor stage 20, wherein the controller 96 is configured to control the second rotational speed of the second compressor stage 20 depending on the first value P1. The value acquisition device 95 and the controller 96 can communicate with one another, and can in each case communicate with components of the heat pump 100, as is indicated in
The value acquisition device 95 is preferably configured for acquiring a second value P2, which corresponds to a second pressure ratio between an outlet of the second compressor stage 20 and an inlet of the first compressor stage 10, or is dependent on the second pressure ratio, and wherein the controller 96 is configured to furthermore control the second rotational speed depending on the second value P2. In particular, a region of the inlet of the second compressor stage 20 can adjoin the region of the outlet of the first compressor stage 10. For example, the region of the outlet of the first compressor stage 10 can end in the sink 32, and the region of the inlet of the second compressor stage 20 can begin in the sink 32 of the vapour duct 30 (see
The controller 96 is preferably configured to use the first value P1 as the actual value and the second value P2 as the target value. Further preferably, the controller 96 is configured to increase the rotational speed of the second compressor stage 20 when the actual value is greater than the target value, or to reduce the rotational speed of the second compressor stage 20 when the actual value is less than the target value. By comparing the actual value with the target value, the rotational speeds of the first and second compressor stage 10, 20 can in each case be set such that the second compressor stage can be used efficiently, independently of the first compressor stage 10. An independent setting of the rotational speeds of the first and second compressor stage 10, 20 is achieved in that each motor M of the compressor stages 10, 20 comprises its own motor shaft, which is to be driven. The first value P1 specifies a compression ratio of the first compressor stage 10 according to P1=TI3/TI1. The second value P2 specifies a compression ratio of the second compressor stage 20 according to P2=TI2/TI3.
The value acquisition device 95 is preferably furthermore configured to ascertain an actual temperature of a cooling fluid 97 discharged on the evaporator side, and in which the controller 96 is configured to set the rotational speed of the first compressor stage 10 in a manner dependent on the actual temperature of the cooling fluid 97 and a predefined target temperature of the cooling fluid 97. During operation of the heat pump 100, it can increase the actual temperature of the cooling fluid 97 discharged on the evaporator side, since the fluid circulating in the heat pump, i.e. the cooling fluid 97, assumes a higher temperature over time due to the operation of the heat pump 100.
The controller is preferably configured to operate the first compressor stage 10 at a higher pressure ratio than the second compressor stage 20, depending on a power requirement in a first power region 98, wherein a difference between the pressure ratios of the first compressor stage 10 and the second compressor stage 20 reduces at increasing power requirements (see case 1 in
The first compressor stage 10 and the second compressor stage 20 preferably comprise radial wheels of different sizes, wherein the controller 96 is configured to control the first compressor stage 10, in the first power region 98, to a constant first pressure ratio as the target value, and to control the second compressor stage 20, with increasing power requirement, to an increasing second pressure ratio as the target value, and to fulfil, in the second power region 99, with an increasing power requirement both by the first compressor stage 10 and also by the second compressor stage 20 (compare with
The controller 96 is preferably configured to use a maximum value from a function of the second value P2 or a predefined constant konst. as the target value for controlling the second rotational speed of the second compressor stage 20. The predefined constant depends on the compressors used and is preferably in the range between 1 and 5, i.e. 1≤konst.≤5, more preferably in the range between 2 and 4, particularly advantageously the constant is konst=2.7. The constant is the optimum pressure ratio of the first compressor. The maximum value of the second rotational speed of the second compressor stage 20 is therefore given by:
maximum value=P2 or konst.
The maximum value is given by a maximum function which takes the higher value from the second value P2 or from a predefined constant konst.
The maximum function is preferably a root function, and the predefined constant is the boundary 94 between the first and the second power region 98, 99. The maximum function is in particular given by
(ρ(TI2)/ρ(TI1))1/2
wherein ρ(TI1) specifies a saturated vapour pressure in the evaporator sump (52), which can, in particular be measured by the first temperature sensor 91, and wherein ρ(TI2) specifies a saturated vapour pressure in the condenser sump 64, which can, in particular be measured by the third temperature sensor 93 (compare with
The first value P1 is given by the ratio from: P1=TI3/TI1.
The second value P2 is given by the ratio from: P2=TI2/TI3.
An overall compression ratio Pges, as is plotted in
As can be seen for example from
The value acquisition device 95 preferably comprises a first temperature sensor for acquiring a first temperature TI1 with respect to the evaporator 50, and a second temperature sensor for acquiring a second temperature TI3 with respect to an outlet of the first compressor stage 10, wherein the value acquisition device 95 is configured to determine the first value P1 from the first temperature TI1 and the second temperature TI3.
The first temperature sensor is preferably arranged in the evaporator sump 52 of the evaporator 50, in order to acquire the first temperature TI1 before the first compressor stage 10, and the second temperature sensor is arranged in an intermediate cooling sump 44, in order to acquire the second temperature TI3 after an outlet of the first compressor 10. The outlet of the first compressor 10 preferably comprises the sink 32 in the vapour duct 30, which fluidically connects the first compressor stage 10 and the second compressor stage 20.
The vapour duct 30 is preferably provided between the first compressor stage 10 and the second compressor stage 20, in order to conduct compressed fluid out of the first compressor stage 10 into the second compressor stage 20, wherein the intermediate cooling sump 44 or the container 45 is arranged in the vapour duct 30. The first compressor stage 10 and the second compressor stage 20 are fluidically interconnected via the vapour duct 30.
As can be seen from
A fluid conducting channel 15 preferably extends from the condenser sump 64 into the intermediate cooling sump 44 (
Preferably a bridging channel 62 is arranged between the first compressor stage 10 and the condenser 60, in order to bridge the second compressor stage 20, wherein a cross-section reducing element 70 is arranged in the bridging channel 62, in order to set a cross-section of the bridging channel 62 for controlling a through-flow of compressed fluid out of the first compressor stage 10 to the condenser 60, wherein the cross-section reducing element 70 assumes a closed position during operation of the second compressor stage 20. The bridging channel 62 and the cross-section reducing element 70 have already been described in detail, to which reference is made.
The rotational speeds of the compressor stages 10, 20 can be increased for two reasons, since both the user side and the cooler side act on the heat pump. For example, the cold water temperature 97 may increase. The water used by the user, which is provided to him, is simply of a higher temperature, i.e. the user requires more cooling capacity. In this case, the rotational speed of the first compressor stage 10 is adjusted upwards, as a result of which more electrical power 104 is supplied to the heat pump 100. As a result, the cooling capacity 103 generated by the heat pump increases. In another case, the cold water temperature 97 may increase if the water temperature from the heat exchanger used as cooler to the liquefier increases, for example if the outside temperature increases and the heat exchanger used as cooler can discharge the heat energy only with greater energy expenditure. In this case, for example the measured temperatures TI1, TI3 and TI2 increase, as a result of which ultimately the cold water temperature increases, which reaches the user. For the operation of the compressor stages 10, 20 this means that initially the rotational speed of the first compressor stage is adjusted upwards and then, in a temporally offset manner, the rotational speed of the second compressor stage is also adjusted upwards. Thus, in the case of an increase in the cooling water temperature the consumed electrical power 104 of the heat pump 100 also increases.
The second compressor can be used more efficiently by means of the heat pump described herein, as a result of which the heat pump per se can be used more efficiently. Furthermore, the second compressor stage is prevented from being operated in the pump limit or in the swallowing limit.
In particular, the first compressor stage provides the user with a required cooling capacity. The second compressor stage 20 discharges the heat from the heat pump 100 to the heat exchanger used as cooler. When the first compressor stage 10 provides the user with more cooling capacity, the compressor stage 20 outputs more heat capacity to the heat exchanger used as cooler, as a result of which the consumed electrical power of the heat pump increases.
A further aspect relates to a method for operating a heat pump 100 comprising an evaporator 50 for evaporating a fluid in order to obtain an evaporated fluid, wherein the evaporator 50 has an evaporator sump 52; a condenser 60 for condensing an evaporated fluid compressed by an N-stage compressor, wherein the condenser 60 has a condenser sump 64, a condensation region 66 and a holding region 67 for holding a vaporous fluid still remaining after the condensation region 66; the N-stage compressor which comprises N compressors, wherein 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 vapour duct 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 vapour-conducting line 92 which is arranged between the condenser 60 and the evaporator 50, in order to conduct vaporous fluid out of the holding region 67 of the condenser 60 into the evaporator 50, which method comprises the following steps:
A further aspect relates to a method for producing a heat pump 100 comprising an evaporator 50 for evaporating a fluid, in order to obtain an evaporated fluid, wherein the evaporator 50 has an evaporator sump 52; a condenser 60 for condensing an evaporated fluid compressed by an N-stage compressor, wherein the condenser 60 has a condenser sump 64, a condensation region 66 and a holding region 67 for holding a vaporous fluid still remaining after the condensation region 66; the N-stage compressor which comprises N compressors, wherein 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 vapour duct 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 vapour-conducting line 92 which is arranged between the condenser 60 and the evaporator 50, in order to conduct vaporous fluid out of the holding region 67 of the condenser 60 into the evaporator 50, which method comprises the following steps:
A further aspect relates to a method for operating a heat pump 100 comprising an evaporator 50 for evaporating a fluid, in order 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 comprises a condenser sump 64; 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 the condenser 60, and is configured to compress the evaporated fluid, in order to obtain the compressed fluid; wherein the method comprises the following steps:
A further aspect relates to a method for producing a heat pump 100 comprising an evaporator 50 for evaporating a fluid in order to obtain an evaporated fluid, wherein the evaporator 50 comprises an evaporator sump 52; a condenser 60 for condensing a compressed fluid, wherein the condenser 60 comprises a condenser sump 64; a compressor having a first compressor stage 10 and a second compressor stage 20, wherein the method comprises:
A further aspect relates to a method for operating a heat pump 100 comprising an evaporator 50 for evaporating a fluid in order to obtain an 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 the condenser 60, and is configured to compress the evaporated fluid, in order to obtain the compressed fluid; and the condenser 60 for condensing the compressed fluid; and an intermediate cooler 40, which is connected to an intermediate cooling fluid feed 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, wherein the method comprises:
A further aspect relates to a method for producing a heat pump 100 comprising an evaporator 50 for evaporating a fluid, in order to obtain an 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; and the condenser 60 for condensing the compressed fluid; wherein the method comprises:
A further aspect relates to a method for operating a heat pump 100 comprising an evaporator 50 for evaporating a fluid, in order to obtain evaporated fluid; a condenser 60 for condensing a compressed fluid; a compressor having a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged in the flow direction of the evaporated fluid, during operation of the heat pump 100, between the evaporator 50 and the condenser 60, and is configured to compress the evaporated fluid, in order to obtain the compressed fluid, and a bridging channel 62 between the first compressor stage 10 and the condenser 60, wherein the method comprises:
A further aspect relates to a method for producing a heat pump 100 comprising an evaporator 50 for evaporating a fluid, in order to obtain evaporated fluid; a condenser 60 for condensing a compressed fluid; a compressor having a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged in the flow direction of the evaporated fluid, during operation of the heat pump 100, between the evaporator 50 and the condenser 60, and is configured to compress the evaporated fluid, in order to obtain the compressed fluid; wherein the method comprises:
A further aspect relates to a method for operating a heat pump 100 comprising an evaporator 50 for evaporating a fluid, in order to obtain an evaporated fluid; a condenser 60 for condensing a compressed fluid; and a compressor having a first compressor stage 10 and a second compressor stage 20, wherein the compressor is arranged in the flow direction of the evaporated fluid, during operation of the heat pump 100, between the evaporator 50 and the condenser 60, and is configured to compress the evaporated fluid, in order to obtain the compressed fluid, said method comprising the following steps:
A further aspect relates to a method for producing a heat pump 100 comprising: an evaporator 50 for evaporating a fluid in order to obtain an evaporated fluid; a condenser 60 for condensing a compressed fluid; and a compressor having a first compressor stage 10 and a second compressor stage 20, said method comprising the following steps:
As already mentioned in the general part, individual aspects which are described with reference to the heat pump can also be implemented as method steps.
Preferably, a method for producing a heat pump 100, as described above, can be provided by preparing the individual features and combining the individual features to one of the heat pump 100 as described above. In the present case, the individual features are not discussed again in connection with the production method for the heat pump. Rather, at this point, reference is made to the above description of the individual features, which can be understood as production method steps.
A method for operating a heat pump 100 further preferably initially comprises providing a heat pump 100 as described above.
For operating the heat pump, at least one, in particular the first, compressor stage 10 is operated. During operation of the first compressor stage 10, fluid is evaporated via the evaporator 50 and thus supplied to the first compressor stage. At the same time, liquid fluid is supplied to an effect element 42 and/or a heat exchanger 82 via the intermediate cooling fluid feed line 3. Evaporated and compressed fluid which leaves the first compressor stage 10 is cooled as has already been described above. The method for operating a heat pump 100 further comprises setting the cross-section reducing element 70 into an open or closed position or an intermediate position, as already described above. Depending on the position of the cross-section reducing element 70, the evaporated and compressed fluid, which leaves the first compressor stage 10, is either conducted directly to the condenser 60 by the bridging channel 62 (inactive vapour path) and/or conducted to the second compressor stage 20 via the vapour duct 30 (active vapour path). In the case of an intermediate position of the cross-section reducing element 70, in particular the inactive and the active vapour path can be used for conducting the evaporated and compressed fluid. A description of the circulation of the fluid already follows from the above description, which is not repeated again in connection with the method for operating the heat pump, in order to avoid redundancies. Rather, at this point too, reference is made to the above description, which can also be understood as method steps for operating the heat pump.
In particular, the various features described can be combined with one another or exchanged with one another as desired. In particular, fluid and cooling water are used synonymously. In particular the use of the word “vapour” means evaporated fluid.
Number | Date | Country | Kind |
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10 2022 203 520.8 | Apr 2022 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2023/059008 | 4/5/2023 | WO |