Method and device for reducing electrical inrush currents of a compressor

Abstract

The invention relates to a method for reducing electrical inrush currents of a compressor (10), in particular of a piston compressor (10), of a fluid-mechanical system, in particular a refrigeration machine or a heat pump, wherein, during operation of the fluid-mechanical system and on each restart of the compressor (10), a rise in fluid pressure (p14) of a fluid (2) in a compression chamber (14) of the compressor (10) is reduced, thereby diminishing current peaks of the inrush currents of an electrical supply current to an electric motor of the compressor (10).

Description

[0001] Description

[0002] title

[0003] Method and device for reducing electrical starting currents of a compressor

[0004] The invention relates to a method for reducing and a device for reducing the electrical starting currents of a compressor, in particular a piston compressor, for a fluid-mechanical entity. Furthermore, the invention relates to a compressor or a fluid-mechanical entity, in particular a refrigeration machine or a heat pump.

[0005] State of the art

[0006] Starting and restarting a piston compressor, for example in a refrigeration unit or heat pump, inherently involves a full stroke, as this is mechanically predetermined by the compressor's crankshaft. In this process, the compressor must overcome the inertia of the moving masses and compress its entire displacement. Particularly during a restart against pressure, i.e., before the fluid pressure in the compressor's compression chamber has significantly dropped, high forces are generated, which, despite the use of a frequency converter, result in a high starting current for the compressor.

[0007] Task

[0008] Since a compressor in a fluid-mechanical system, such as a refrigeration unit or a heat pump, typically operates intermittently, the high mechanical forces generated during its restarts have a significant impact on its energy efficiency. There are ongoing efforts to improve fluid-mechanical systems and, in particular, to design them to be more cost-effective with regard to their operating and manufacturing costs. It is therefore an object of the invention to provide an improved fluid-mechanical system, especially one that is more cost-effective in terms of its operating costs.

[0009] Disclosure of the invention

[0010] The object of the invention is achieved by a method for reducing and a device for reducing the electrical starting currents of a compressor, in particular a piston compressor, for a fluid-mechanical entity, in particular a refrigeration machine or a heat pump, and by means of a compressor or a fluid-mechanical entity, in particular a refrigeration machine or a heat pump. Advantageous embodiments, additional features and / or advantages of the invention will become apparent from the dependent claims and the following description.

[0011] Since a compressor, especially a piston compressor, typically operates intermittently for a fluid-mechanical entity such as a refrigeration unit (e.g., a refrigerator), a heat pump, a compressed air device, etc., current peaks in the starting currents or in the starting currents of the compressor's electrical supply have a significant impact on the energy efficiency of both the compressor and the fluid-mechanical entity. The fluid being compressed is, for example, a refrigerant, a coolant, air, etc.

[0012] In the current reduction method according to the invention, during compressor start-up and / or during restarts of the compressor by the fluid-mechanical entity, the increasing fluid pressure in a compression chamber of the compressor is reduced, thereby reducing current peaks in the starting current of the compressor's electric motor. During operation of the fluid-mechanical entity, the compressor is preferably operated in intermittently, during which it repeatedly starts and stops. The fluid-mechanical entity can, of course, also be configured as a compressor.During compressor start-up and / or restart, the increasing fluid pressure in the compression chamber can be relieved (reduced), whereby in particular the volume of fluid delivered by the compressor is reduced and / or at least a volume fraction of the delivered fluid is not compressed and / or only partially compressed. Within the scope of this specification, the terms "displacement" and "delivery" of the fluid are not to be understood as compression. This means that compression of the fluid can only occur with the inlet valve and outlet valve closed.

[0013] The fluid-mechanical entity and / or the compressor may include a starting flow reduction device that can reduce the rising fluid pressure in the compression chamber by restricting fluid flow into the compression chamber, allowing fluid flow through the compression chamber, allowing fluid flow out of the compression chamber, and / or allowing fluid to flow past the compression chamber. This can occur during the start-up and / or restart of a piston compressor during its compression strokes.

[0014] During compressor start-up and / or restart, the fluid can be decompressed during intake and / or displacement by the compressor. Furthermore, fluid flowing into the compression chamber through an inlet section of the compressor can be throttled. This can be achieved by an adjustable fluid throttle (metering unit) in the inlet section (see below).

[0015] Furthermore, fluid flowing into the compression chamber through the compressor's inlet section can be returned to the inlet section instead of being compressed. This can be achieved via an inlet valve in the compressor's inlet section (see below). Additionally, fluid flowing into the compression chamber through the compressor's inlet section can be directed to an outlet section instead of being compressed. This can be achieved via a start-up relief valve in the compressor's outlet section (see below).

[0016] Furthermore, a fluid passing through the compressor's inlet section can be conveyed at least into a bypass of the compression chamber and, if necessary, also through it and / or into a low-pressure fluid reservoir. The bypass can be designed as a parallel bypass, an antiparallel bypass, or a wastegate. The low-pressure fluid reservoir can also be a fluid-tight reservoir, e.g., the hermetic housing of a compressor for a refrigerator, or an open reservoir, e.g., the surrounding environment in a compressed air device.

[0017] During start-up and / or restart, the fluid pressure in the compression chamber can be gradually increased. For example, in a piston compressor, with its progressive strokes during start-up and / or restart, the fluid pressure in the compression chamber assumes increasing average and / or maximum values ​​over time. After the compressor has started and / or restarted, the fluid pressure in the compression chamber tends to remain at its nominal level.

[0018] This means that during nominal operation of the compressor while the fluid-mechanical entity is running, the fluid pressure in the compression chamber is essentially unaffected, e.g., by means of a starting current reduction device. When the compressor stops, the fluid pressure in the compression chamber cannot be reduced, or it can be reduced analogously according to the invention. Furthermore, the starting current reduction device can, of course, be designed as a starting current reduction device according to the invention (see below).

[0019] The inrush current reduction device according to the invention comprises a compression chamber for the compressor, as well as an inlet section preferably with an inlet valve and / or an outlet section preferably with an outlet valve for the compression chamber, wherein the inlet section and / or the outlet section has a fluid pressure reduction device by means of which, during a start and / or restart of the compressor, an increase in the fluid pressure of a fluid in the compression chamber can be reduced (decompressed) and thus current peaks of the starting currents of an electrical supply current of an electric motor for the compressor can be reduced.

[0020] The inlet section and / or the outlet section can each be configured as at least one fluid line. Furthermore, the inlet valve and / or the outlet valve can be configured as an active, i.e., regulated / controlled, or as a passive, i.e., mechanical, valve. In the simplest case, as in the prior art, such a valve is configured as a simple mechanical check valve.

[0021] According to the invention, peak forces and torques of the electric motor driving the compressor, which arise from the compressor's compression cycles (e.g., piston strokes), are reduced during restarts of the electric motor and / or the compressor (including the electric motor), and also during initial startup. This reduced torque lowers the electric motor's current draw and thus the energy required. This significantly reduces the compressor's operating costs. Furthermore, the electric motor required can be smaller because the high torque peaks during startup and restarts are mitigated, saving additional energy, materials, and therefore costs.

[0022] The fluid pressure reduction device can be designed and / or integrated into the starting current reduction device in such a way that the respective increase in fluid pressure in the compression chamber can be reduced by means of a controllable intake and / or displacement of the fluid. Thus, the fluid pressure reduction device can partially decompress the fluid in the compression chamber during intake and / or displacement. Furthermore, it can throttle the fluid flow in the inlet section during intake. Additionally, the fluid pressure reduction device can recirculate fluid from the compression chamber back into the inlet section during compression. Finally, it can pump fluid from the compression chamber into the outlet section during compression.Furthermore, during suction and / or displacement of the fluid, the fluid can be conveyed at least into a bypass and / or into a low-pressure fluid reservoir.

[0023] Such a reduction is intended to mean that a volume of fluid that can be conveyed or conveyed according to the invention, or that can be displaced or displaced according to the invention, i.e., a potentially or subsequently actually compressible or compressed volume of the fluid and / or a counter-fluid pressure for this volume, is lower due to the fluid pressure reduction device than if the starting current reduction device or the fluid pressure reduction device were not present.

[0024] The fluid pressure reduction device can be implemented as a controllable / adjustable throttle valve and / or a controllable / adjustable inlet valve in the inlet section. During compressor start-up and / or restart, the controllable / adjustable throttle valve can be set to at least partially restricting and / or the controllable / adjustable inlet valve can be at least partially open.

[0025] In suction throttling, the controlled / regulated throttle valve (metering unit) is preferably placed upstream of the intake valve of the compression chamber in the intake section, which reduces the amount of fluid drawn in.

[0026] This means that when the compressor restarts, a significantly reduced amount of fluid is delivered. With a piston compressor, only a small volume of fluid can be filled per stroke, so subsequent fluid pressure build-up is not necessary. Therefore, only a lower torque is required from the electric motor, and consequently, the starting current decreases when the compressor restarts. The fluid throttle can also be located downstream of the inlet valve in the inlet section.

[0027] As a controlled / regulated suction valve, e.g., one that is normally open, the inlet valve can be held in its open position until the compressor has started. Since the inlet valve can also be controlled / regulated during restarts via a suitable control system, it is further possible to transiently adjust the amount of fluid delivered, thus achieving a smooth torque increase during the start-up and / or restart of the electric motor. As long as the inlet valve is held at least partially open, any fluid drawn in during compression is pushed back into the inlet section and is not compressed by a closed outlet valve.

[0028] The fluid pressure reduction device can be implemented as a start-up relief valve (decompression valve) in the outlet section, a bypass, and / or a line to a low-pressure fluid reservoir. During compressor start-up and / or restart, the start-up relief valve can be at least partially open, the bypass at least partially configured, and / or the line to the low-pressure fluid reservoir at least partially functional, i.e., fluid can flow through it. Depending on the location of the device, the outlet valve must be open or may be closed.

[0029] The start-up relief valve can be located upstream or downstream of the outlet valve. For reducing the fluid pressure in the compression chamber, the outlet valve can be open or, preferably, closed if the start-up relief valve is located upstream. If the start-up relief valve is located downstream, the outlet valve must be open. With an electric and / or mechanical start-up relief valve, preferably located downstream of the outlet valve: As long as a minimum fluid pressure is not reached or the start-up relief valve is not closed by an actuator, the compressor delivers the fluid through the start-up relief valve during a restart phase without a significant pressure build-up.

[0030] Only when the fluid pressure is high enough (mechanical start-up relief valve) or the start-up relief valve is closed (electrically controlled / regulated start-up relief valve) is a fluid pressure build-up allowed in the compression chamber and a quantity of fluid actively compressed (exhaust valve naturally closed). A spring in a mechanical start-up relief valve must be designed such that pressure pulsations above a defined minimum speed of the electric motor close the start-up relief valve, thus allowing further fluid pressure build-up.

[0031] In a bypass, fluid can at least be stored in it and / or pumped around the compression chamber. In a low-pressure fluid reservoir, fluid can be pumped into it, whereby the fluid can be pumped around the compression chamber and / or through the compression chamber.

[0032] The compressor or fluid-mechanical entity according to the invention comprises a control unit, wherein a current reduction method according to the invention can be implemented and / or is implemented by means of the control unit, and / or the compressor or fluid-mechanical entity comprises a starting current reduction device according to the invention. An open or a closed fluid circuit can be operated by means of the compressor. A closed fluid circuit is designed in particular as a refrigerant circuit and an open fluid circuit is designed in particular as an air circuit.

[0033] In the case of a deactivated compressor or fluid mechanical entity, the current reduction method can preferably be performed and / or carried out at every start-up. Furthermore, during operation of the compressor or fluid mechanical entity, the current reduction method can preferably be performed and / or carried out at every restart of the compressor.

[0034] Within the scope of this specification, a decommissioned fluid mechanical entity is defined as a fluid mechanical entity that is de-energized or essentially de-energized. If the fluid mechanical entity is no longer de-energized in this way, it is ready for operation or is already in operation. If the fluid mechanical entity is ready for operation, it is brought into operation for the first time or repeatedly by a start-up. This applies analogously to the compressor. If the fluid mechanical entity is in operation, its compressor can be in an active (compressor running) or an inactive (compressor not running) state. If the compressor transitions from its inactive state to its active state, this occurs—apart from a start-up of the fluid mechanical entity—by restarting the compressor.

[0035] Brief description of the characters

[0036] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying schematic drawing, which is not to scale. In the invention, a feature can be positive (i.e., present) or negative (i.e., absent). In this specification, a negative feature is not explicitly defined as a feature unless the invention specifically emphasizes its absence. That is, the actual invention, rather than one constructed by the prior art, consists of omitting this feature. The absence of a feature (negative feature) in an exemplary embodiment indicates that the feature may be optional (to a person skilled in the art). The figures (Fig.) in the drawing, which are merely exemplary and schematic, show:

[0037] Fig. 1 shows a schematic diagram of a refrigerant circuit of a fluid-mechanical entity designed as a refrigeration machine, e.g., a refrigerator; Fig. 2 shows a schematic diagram of a cutaway piston compressor for a fluid-mechanical entity; Fig. 3 shows, according to the prior art, a section of a fluid-mechanical circuit diagram of a fluid-mechanical entity in a region of its compressor; Fig. 4 shows a flowchart of a method according to the invention for reducing electrical starting currents of a compressor; and Figs. 5 to 7 show, according to the invention, each a section of a fluid-mechanical circuit diagram for a fluid-mechanical entity in a region of its compressor.

[0038] Embodiments of the invention

[0039] The invention – a current reduction method for the electrical starting currents of a (fluid) compressor 10 (see Fig. 4) and a starting current reduction device for a (fluid) compressor 10 (see Figs. 5 to 7) – is explained in more detail with reference to a fluid circuit 4 designed as a refrigerant circuit 4 for a fluid-mechanical entity 1 designed as a refrigeration machine 1, e.g., a refrigerator 1 (see Figs. 1 and 2). Alternatively or additionally, the fluid-mechanical entity 1 can be designed, for example, as a heat pump 1, a compressed air device 1, etc. In principle, the invention is applicable to all compressors 10, in particular piston compressors 10, e.g., for such fluid-mechanical entities 1.

[0040] The drawing shows only those sections of fluid circuit 4 that are necessary for understanding the invention. Although the invention is described and illustrated in detail by preferred embodiments, the invention is not limited by the disclosed embodiments. Other variations can be derived from them without departing from the scope of protection of the invention.

[0041] Fig. 1 shows the fluid circuit 4 with: the compressor 10, in particular the piston compressor 10, downstream of it a condenser 20, downstream of it an expansion throttle 30 and downstream of it an evaporator 40. A fluid 2, here a refrigerant 2, pressurized by the compressor 10 to a pressure p, can be conveyed through its outlet section 200 or outlet line 200 (see also Fig. 2) in the fluid circuit 4 via the condenser 20, the expansion throttle 30 and the evaporator 40 and finally returns to the compressor 10, which for this purpose includes an inlet section 100 or an inlet line 100.

[0042] Figure 2 shows a piston compressor 10 in more detail, wherein the fluid 2 can be compressed in a compression chamber 14 or a working chamber 14 of the compressor 10. A time-varying fluid pressure in the compression chamber 14 is denoted by pi4. The energy for compressing the fluid 2 in the compression chamber 14 comes from a crankshaft 12 of the compressor 10, to which the electric motor (not shown) for the compressor 10 is connected via a torque-locking mechanism.

[0043] The compression chamber 14 is connected via an inlet valve 110 in the inlet section.

[0044] The inlet section 100 of or for the compressor 10 can be brought into fluid communication with the upstream, high-pressure-side fluid circuit 4, wherein the inlet section 100 can be designed as an inlet line 100 or a part of the inlet line 100 of or for the compressor 10 - see Figs. 2 and 3. The inlet section 100 or the inlet line 100 is a section of the fluid circuit 4. In the simplest case, the inlet valve 110 is designed as a simple, mechanical check valve 110.

[0045] Furthermore, the compression chamber 14 can be connected to the downstream, low-pressure fluid circuit 4 via an outlet valve 210 in the outlet section 200 of or for the compressor 10, wherein the outlet section 200 can be configured as an outlet line 200 or part of an outlet line 200 of or for the compressor 10 – see again Figures 2 and 3. The outlet section 200 or the outlet line 200 is a section of the fluid circuit 4. In the simplest case, the outlet valve 210 is configured as a simple mechanical check valve 210.

[0046] The compressor 10 can be driven by the electric motor in intermittent operation. The electric motor can be part of a drive unit, i.e., a structural unit comprising the electric motor and a gearbox. Typically, compressors 10 for refrigeration machines 10, especially refrigerators 10, use asynchronous motors whose speed is controlled by a frequency converter (inverter). An asynchronous motor 10 connected directly to an electrical supply voltage typically exhibits very high current peaks during the starting current of its supply current.

[0047] Figure 4 shows a simple flowchart illustrating three of a plurality of possible operating states of the fluid-mechanical entity 1. Position 400 represents the start of the fluid-mechanical entity 1, position 410 a restart of the compressor 10 of the fluid-mechanical entity 1, and position 420 nominal operation of the compressor 10. The compressor 10 also starts either when the fluid-mechanical entity 1 starts (position 400) or with a slight time delay (position 400) after the start of the fluid-mechanical entity 1. For definitions, see above. According to the invention - see Fig. 4 (current reduction method) and Figs. 5 to 7 (starting current reduction device) - a rising fluid pressure pi4 of the fluid 2 in the compression chamber 14 can preferably be reduced by means of a fluid pressure reduction device 300 (see Figs. 5 to 7).If this occurs during restarts 410 of compressor 10 while the fluid-mechanical entity 1 is operating, current peaks of the starting currents of the electrical supply current of an electric motor of compressor 10 can be significantly reduced. This applies analogously to a start 400 of compressor 10.

[0048] The fluid pressure reduction device 300 is associated with the inlet section 100 and / or the outlet section 200. It is also possible to provide the fluid pressure reduction device 300 away from the inlet section 100 and / or away from the outlet section 200, in which case the fluid pressure reduction device 300 can, for example, be positioned at the compression chamber 14 in such a way that it can be brought into direct fluid communication with the compression chamber 14.

[0049] During a restart of compressor 10, the current reduction process can relieve the increasing fluid pressure P14 in the compression chamber 14. This pressure relief means that, due to the pressure relief, the fluid pressure P14 in the compression chamber 14 assumes a lower average or maximum value during the (potential) compression (in the case of a piston compressor 10: during the piston strokes) of fluid 2 than if the current reduction process were not carried out. The current reduction process transforms compression into, for example, a displacement of fluid 2.

[0050] Pressure relief can occur on the inlet and / or outlet side. Inlet-side pressure relief can occur during intake (piston compressor: piston moves towards bottom dead center) and / or (potential) compression (piston compressor: piston moves towards top dead center), and outlet-side pressure relief can occur particularly during (potential) compression. An inlet-side measure can, in particular, be a volume-reduced delivery of the fluid 2. An inlet-side and / or outlet-side measure can, in particular, be a volume-reduced compression of the fluid 2, whereby the compression of the fluid 2 is converted into at least a partial displacement of the fluid 2. Under certain circumstances, the compression is essentially completely converted into a displacement of the fluid 2.

[0051] During intake, fluid 2 can be conveyed decompressed and / or at a throttled rate. Furthermore, during (potential) compression, i.e., the displacement of fluid 2, it can be conveyed decompressed, returned to inlet section 100, and / or conveyed further to outlet section 200. Additionally, fluid 2 can be conveyed into or through a bypass (not shown) and / or into a low-pressure fluid reservoir (not shown). - See also above.

[0052] Fig. 5 (intake throttling 300, 310) shows a first embodiment of the starting current reduction device 300, 310, which is designed as a controllable / regulated (intake) throttle valve 310 or a controllable / regulated (intake) fluid throttle 310, i.e., as a metering unit 300, 310. The throttle valve 310 is located in the inlet section upstream of the inlet valve 110, but can also be located downstream of the inlet valve 110 in the inlet section 100.

[0053] When the compressor 10 restarts, a throttled intake of fluid 2 into the compression chamber 14 reduces the amount of fluid 2 that enters the chamber. This fluid is then not compressed as highly as during normal operation of the compressor 10, when the throttle valve 310 is not configured to throttle. In other words, in this embodiment, the amount of fluid 2 drawn in or delivered during the (re)start of the electric motor is reduced by means of a throttle valve 310. - See also above.

[0054] Fig. 6 (suction valve 110; 300, 320) shows a second embodiment of the starting current reduction device 300, 320, in which it is designed as an electrically controllable / adjustable inlet valve 110; 300, 320. Here, the inlet valve 110; 300, 320 is configured as a controllable / adjustable suction valve 110; 300, 320. Of course, another controllable / adjustable inlet valve 110; 300, 320, for example in the form of a solenoid valve, is applicable. When restarting the compressor 10, the inlet valve 110; 300, 320, with a cross-section that may be variable, can be left open until the compressor 10 has essentially started up. - See also above.

[0055] Fig. 7 (decompression valve 300, 330) shows a third embodiment of the starting current reduction device 300, 330, which is designed as an electrically controllable / regulated and / or mechanical starting relief valve 300, 330. The starting relief valve 330 is located in the outlet section 200 downstream of the outlet valve 210, but can also be located upstream of the inlet valve 210 in the outlet section 200. The starting relief valve 330 branches off from the fluid circuit 4 and leads, for example, into a hermetically sealed housing or a reservoir containing fluid 2. - See also above.

[0056] Furthermore, it is possible to design the inrush current reduction device 300 as a controlled / regulated three-way outlet valve 300, 210, a bypass 300 bypassing or short-circuiting the compressor 10, and / or a line 300 into a low-pressure fluid reservoir, etc. (all not shown). - See also above.

Claims

Claims 1. Method for reducing electrical starting currents of a compressor (10), in particular a piston compressor (10), a fluid mechanical entity (1), in particular a refrigeration machine (1) or a heat pump (1), characterized in that during operation of the fluid mechanical entity (1) during restarts (410) of the compressor (10), a progressively increasing fluid pressure (P14) of a fluid (2) in a compression chamber (14) of the compressor (10) is reduced, and thus current peaks of the starting currents of an electrical supply current of an electric motor of the compressor (10) are reduced.

2. Current reduction method according to the preceding claim, characterized in that a fluid pressure (P14) increasing in the compression chamber (14) during a restart (410) of the compressor (10) is pressure relieved, wherein in particular a volume of the fluid (2) conveyed by the compressor (10) is reduced and / or in particular at least a volume fraction of the conveyed fluid (2) is not and / or only conditionally compressed.

3. Current reduction method according to one of the preceding claims, characterized in that the fluid mechanical entity (1) and / or the compressor (10) has a starting current reduction device by which the increasing fluid pressure (P14) in the compression chamber (14) can be reduced, wherein an inflow of fluid (2) into the compression chamber (14) is hindered, a flow of fluid (2) through the compression chamber (14) is enabled, a flow of fluid (2) out of the compression chamber (14) is enabled, and / or a flow of fluid (2) past the compression chamber (14) is provided.

4. Current reduction method according to one of the preceding claims, characterized in that during a restart (410) of the compressor (10): • when the fluid (2) is drawn in and / or moved by the compressor (10), the fluid (2) is conveyed in a decompressive manner, • a fluid (2) flowing into the compression chamber (14) through an inlet section (100) of the compressor (10) is conveyed in a throttled manner, • a fluid (2) flowing into the compression chamber (14) through the inlet section (100) of the compressor (10) is pumped back into the inlet section (100) instead of being compressed, • a fluid (2) flowing into the compression chamber (14) through the inlet section (100) of the compressor (10) is conveyed into an outlet section (200) instead of being compressed, and / or • a fluid (2) passing through the inlet section (100) of the compressor (10) is conveyed at least into a bypass of the compression chamber (14) and / or into a low-pressure fluid reservoir.

5. Current reduction method according to one of the preceding claims, characterized in that: • during a restart (410) the fluid pressure (P14) in the compression chamber (14) is successively increased, • after a restart (410) of the compressor (10) the fluid pressure (P14) in the compression chamber (14) proceeds nominally, and / or • the inrush current reduction device is designed according to one of the following claims.

6. Device for reducing electrical starting currents of a compressor (10), in particular a piston compressor (10), for a fluid mechanical entity (1), in particular a refrigeration machine (1) or a heat pump (1), comprising a compression chamber (14) for the compressor (10) and an inlet section (100) with an inlet valve (110) and / or an outlet section (200) with an outlet valve (210) for the compression chamber (14), characterized in that the inlet section (100) and / or the outlet section (200) has a fluid pressure reduction device (300) by means of which, during restarts of the compressor (10), an increase in the fluid pressure (P14) of a fluid (2) in the compression chamber (14) can be reduced and thus current peaks of the starting currents of an electrical supply current of an electric motor for the compressor (10) can be reduced.

7. Starting current reduction device according to the preceding claim, characterized in that the fluid pressure reduction device (300) is designed and / or arranged in the starting current reduction device in such a way that the respective increase of the fluid pressure (P14) in the compression chamber (14) can be reduced by means of a controllable suction and / or a controllable displacement of the fluid (1).

8. Starting current reduction device according to one of the preceding claims, characterized in that by means of the fluid pressure reduction device (300): • during a suction and / or displacement of the fluid (2) a partial decompression of the fluid (2) in the compression chamber (14) can be achieved, • during the intake of the fluid (2) a throttling of the fluid (2) in the inlet section (100) can be achieved, • during compression of the fluid (2) a recovery of the fluid (2) from the compression chamber (14) back into the inlet section (100) is possible, • during compression of the fluid (2) a conveyance of the fluid (2) from the compression chamber (14) into the outlet section (200), and / or • during a suction and / or displacement of the fluid (2), the fluid (2) can be conveyed at least into a bypass and / or into a low-pressure fluid reservoir.

9. Starting current reduction device according to one of the preceding claims, characterized in that the fluid pressure reduction device (300) is implemented as a controllable / regulated throttle valve (300, 310) and / or a controllable / regulated inlet valve (300, 110) in the inlet section (100), wherein during the restart of the compressor (10), the controllable / regulated throttle valve (300, 310) is set at least partially to throttle and / or the controllable / regulated inlet valve (110, 300) is at least partially open.

10. Starting current reduction device according to one of the preceding claims, characterized in that the fluid pressure reduction device (300) is implemented as a starting relief valve (300, 330) in the outlet section (100), a bypass and / or a line into a low-pressure fluid reservoir, wherein during the restart of the compressor (10), the starting relief valve (300, 330) is at least partially open, the bypass is at least partially set up and / or the line into the low-pressure fluid reservoir is at least partially functional.

11. Compressor (10) or fluid-mechanical entity (1), in particular refrigeration machine (1) or heat pump (1), wherein the compressor (10) or the fluid-mechanical entity (1) has a control unit, characterized in that a current reduction method according to one of the preceding claims can be carried out and / or is carried out by the control unit, and / or the compressor (10) or the fluid-mechanical entity (1) has a starting current reduction device according to one of the preceding claims.

12. Compressor (10) or fluid mechanical entity (1) according to one of the preceding claims, characterized in that: • an open or a closed fluid circuit (4) can be operated by means of the compressor (10), • in the case of a shut-down compressor (10) or a shut-down fluid mechanical entity (1), the current reduction procedure is feasible and / or is carried out preferably at every start, and / or • during operation of the compressor (10) or the fluid mechanical entity (1), the current reduction procedure is feasible and / or is carried out preferably at each restart of the compressor (10).

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