WO2024089158A1

WO2024089158A1 - Compression system

Info

Publication number: WO2024089158A1
Application number: PCT/EP2023/079894
Authority: WO
Inventors: Veronika WOLF; Stephan Leyer
Original assignee: Universite Du Luxembourg
Priority date: 2022-10-27
Filing date: 2023-10-26
Publication date: 2024-05-02

Abstract

An aspect of the present invention relates to a compression system for compressing a fluid. The system comprises: a buffer reservoir comprising first and second buffer reservoir chambers separated by an actionable fluid barrier, the actionable fluid barrier being arranged fluid tight in the buffer reservoir so as to fluidically isolate the first and the second buffer reservoir chambers. The system further comprises a pressurizer reservoir comprising first and second pressurizer reservoir chambers separated by a movable fluid barrier, the movable fluid barrier being arranged fluid tight in the pressurizer reservoir so as to fluidically isolate the first and the second pressurizer reservoir chambers, the pressurizer reservoir further comprising a heat exchanger for exchanging heat with the first and the second pressurizer reservoir chambers. Also comprised in the system are a first supply line fluidically connecting the first buffer reservoir chamber and the first pressurizer reservoir chamber; a second supply line fluidically connecting the first buffer reservoir chamber and the second pressurizer reservoir chamber; a first discharge line fluidically connecting the second buffer reservoir chamber and the first pressurizer reservoir chamber; and a second discharge line fluidically connecting the second buffer reservoir chamber and the second pressurizer reservoir chamber.

Description

DESCRIPTION

COMPRESSION SYSTEM

Field of the Invention

[oooi] The invention generally relates to a compression system for compressing a fluid (e.g. a gas, a liquid or a combination thereof) and a method for operating the same.

Background of the Invention

[0002] For pressurizing a fluid, a compressor or pump is typically used, depending on whether the fluid is in gaseous or liquid state, respectively. These devices are known for providing a steady mass flow. However, these devices consume large amounts of electrical energy.

[0003] The working principle includes various layouts like rotary vane compressors, reciprocating compressors with moving pistons screw compressors and scroll compressors. Devices like compressors or pumps transferring electrical energy into compression work with efficiencies ranging from 65 to 90 percent.

[0004] To reduce electricity consumption, low temperature (waste-) heat can be used to pressurize a fluid instead. Few devices exist for this application, called “thermal compressor”. Current state of the art for thermal compressors is a bulky system consistent of several vessels and heat exchangers, operated typically in a batch mode. External force is applied to the systems (i.e. electricity) to facilitate the movement of a piston within a vessel. Thus, the system operation still relies on a reduced amount of use electrical energy compared to conventional compressors and pumps.

General Description

[0005] A first aspect of the present invention relates to a compression system for compressing a fluid. The system comprises: o a buffer reservoir comprising first and second buffer reservoir chambers separated by an actionable fluid barrier, the actionable fluid barrier being arranged fluid tight in the buffer reservoir so as to fluidically isolate the first and the second buffer reservoir chambers; o a pressurizer reservoir comprising first and second pressurizer reservoir chambers separated by a movable fluid barrier, the movable fluid barrier being arranged fluid tight in the pressurizer reservoir so as to fluidically isolate the first and the second pressurizer reservoir chambers, the pressurizer reservoir further comprising a heat exchanger for exchanging heat with the first and the second pressurizer reservoir chambers; o a first supply line fluidically connecting the first buffer reservoir chamber and the first pressurizer reservoir chamber; o a second supply line fluidically connecting the first buffer reservoir chamber and the second pressurizer reservoir chamber; o a first discharge line fluidically connecting the second buffer reservoir chamber and the first pressurizer reservoir chamber; and o a second discharge line fluidically connecting the second buffer reservoir chamber and the second pressurizer reservoir chamber.

[0006] In such a compression system, the fluid may only be transferred from one chamber to another chamber through the lines connecting the aforementioned chambers.

[0007] As used herein, a fluid may be a gas, a liquid or a combination thereof, i.e. the liquid may comprises two phases which coexist. Also, it may be noted that the compression system may impose conditions such that the physical state (i.e. gas or liquid) of the fluid may change during compression (e.g. the proportion of gas with respect to fluid).

[0008] As used herein, a fluid barrier is a barrier that partitions the reservoir in two partitions, i.e. chambers, in a fluid-tight manner. Actioning and/or moving the fluid barriers allows for changing the volume ratio of the respective chambers within a particular reservoir, the total volume of both chambers within a particular reservoir remaining constant.

[0009] The first aspect of the present invention allows for compressing both a gas and a liquid, in stark contrast to conventional compression devices, i.e. compressors or pumps. Indeed, the conventional compression devices are limited to distinct fluid phase. Pumps only allow an operation with the fluid being liquid at the entry and liquid at the exit of the component. Whereas compressors handle fluid in gaseous state solely (entry and exit). [ooio] Further, the first aspect of the present invention allows for compressing fluids with a simple device comprising few components. For example, only one heat exchange is necessary in order to achieved compression of the fluid. High investment costs and potentially high maintenance efforts are thereby greatly reduced. In an embodiment, the compression system comprises a single heat exchanger.

[oon] As is readily apparent, the compression system according to the first aspect of the present invention allows for imposing isochoric transformation to the fluid.

[0012] In an embodiment, the compression system comprises at least one of an inlet fluidically connected to the first buffer reservoir chamber and an outlet fluidically connected to the second buffer reservoir chamber.

[0013] In an embodiment, the compression system comprises one or more valves arranged for selectively opening or closing the first supply line, the second supply line, the first discharge line, second discharge line, inlet and/ or the outlet. The valves may be individually operable.

[0014] In an embodiment, the compression system comprises a driving device for driving the actionable fluid barrier. The driving device may be configured to apply a periodic driving to the actionable fluid barrier, preferably to apply an asymmetric periodic driving. A period of the periodic driving may be comprised in the range from 10 Hz to 100 Hz.

[0015] In an embodiment, the buffer reservoir and the pressurizer reservoir have substantially equal volumes, preferably in the range from 0.005 to 0.83 m3, more preferably in the range from 0.01 to 0.75 m3. By substantially equal volumes, it is meant that the volume ratio does not differ from more than 5%, preferably from more than 2%, even more preferably the volumes are equal.

[0016] In an embodiment, a ratio between the movable fluid barrier diameter and the buffer reservoir height is comprised in the range from 0.0002 to 0.002, preferably in the range from 0.0005 to 0.001.

[0017] The compression system may further comprise a controller for controlling the one or more valves arranged for selectively opening or closing the first supply line, the second supply line, the first discharge line, second discharge line, inlet and/ or the outlet.

[0018] The first supply line, the second supply line, the first discharge line, second discharge line, inlet and/or the outlet may be thermally insulated. Typical thermal insulation coefficients may be comprised in the range from 0,02 to 0,057 W/(m*K).

[0019] A second aspect of the present invention relates to a method for operating the compressing system according to the first aspect of the present invention, comprising: o driving the actionable fluid barrier with the driving device; and o exchanging heat with the first and the second pressurizer reservoir chambers.

[0020] The method may further comprise selectively opening or closing the one or more valves of the first supply line, the second supply line, the first discharge line, second discharge line, inlet and/or the outlet. In other words, the valves are individually operable for opening or closing.

[0021] The driving may be periodic, preferably the periodic driving is asymmetric. A period of the periodic driving may be comprised in the range from 10 Hz to 100 Hz.

[0022] A third aspect of the present invention relates to a controller configured to carry out the steps of the method according to the second aspect of the present invention.

[0023] A fourth aspect of the present invention relates to a computer program product comprising a program for operating a controller connected to a compression system according to the first aspect of the present invention, the program comprising instructions, which, when executed by the controller, causes the controller to carry out the steps of the method according to the second aspect of the present invention.

[0024] In the present document, the verb “to comprise” and the expression “to be comprised of” are used as open transitional phrases meaning “to include” or “to consist at least of’. Unless otherwise implied by context, the use of singular word form is intended to encompass the plural, except when the cardinal number “one” is used: “one” herein means “exactly one”. Ordinal numbers (“first”, “second”, etc.) are used herein to differentiate between different instances of a generic object; no particular order, importance or hierarchy is intended to be implied by the use of these expressions. Furthermore, when plural instances of an object are referred to by ordinal numbers, this does not necessarily mean that no other instances of that object are present (unless this follows clearly from context). When reference is made to “an embodiment”, “one embodiment”, “embodiments”, etc., this means that these embodiments may be combined with one another. Furthermore, the features of those embodiments can be used in the combination explicitly presented but also that the features can be combined across embodiments without departing from the invention, unless it follows from context that features cannot be combined.

Brief Description of the Drawings

[0025] By way of example, preferred, non-limiting embodiments of the invention will now be described in detail with reference to the accompanying drawings, in which:

[0026] The accompanying drawings illustrate several aspects of the present invention and, together with the detailed description, serve to explain the principles thereof. In the drawings:

Fig. 1: is a schematic layout of a link between a system application and a compression system according to an embodiment; and

Figs. 2-15: are schematic layouts of the compression system in different states, according to an embodiment of the present invention.

[0027] The reader’s attention is drawn to the fact that the drawings are not to scale. Furthermore, for the sake of clarity, proportions between height, length and/ or width may not have been represented correctly.

Detailed Description of Preferred Embodiments of the Invention

[0028] Fig. 1 show a typical configuration comprising a system application 10 which needs pressurized fluid to operate. In order to provide pressurized fluid, a compression system 12 is also provided, which provides pressurized fluid to the system application 10. In the embodiment as illustrated in Fig. 1, the system application 10 also feeds unpressurized fluid back to the compression system 12 in order to pressurize the fluid again. In other embodiments, the loop maybe open, i.e. the fluid that was pressurized by the compression system 12 is not fed back to the compression system 12 after being used by the system application 10.

[0029] In the embodiment depicted in Fig. 1, the system application is connected to the compression system via two lines, i.e. the inflow line 14 feeding the compression system 12 with unpressurized fluid and an outflow line 16 feeding the system application 10 with pressurized fluid, after the unpressurized fluid being pressurized by the compression system 12.

[0030] It is worthwhile noting that the reference to pressurized and unpressurized fluid refers to the fact that the pressure of the pressurized fluid is greater than the pressure of the unpressurized fluid. The actual pressure of the unpressurized fluid and the pressurized fluid will depend on the requirements of the system application.

[0031] In an embodiment, the compression system 12 may continuously provide pressurized fluid to the system application 10.

[0032] Fig. 2 shows in greater details the compression system 12. The system comprises a buffer reservoir 18, a pressurizer reservoir 20 and four lines 22, 24, 26, 28, which may be selectively opened or closed so as to let fluid pass through them or not. Said selectivity may be achieved by equipping the lines with valves 30, 32, 34, 36 which may be operated to open or close the lines 22, 24, 26, 28. In other words, each line may be equipped with a valve to regulate a mass flow transiting through the line.

[0033] In the present embodiment, the buffer reservoir 18 is a buffer tank 18 and the pressurizer reservoir 20 is a pressurizer tank 20. Of course, other reservoirs are contemplated.

[0034] The compression system 12 further comprises an inlet 38 so as to allow unpressurized fluid to enter the buffer tank 18 and an outlet 40 so as to allow pressurized fluid to exit the buffer tank 18 towards the system application. The inflow line 14 may be connected to the inlet 38 and the outflow line 16 may be connected to the outlet 40. The inflow and outflow lines (and/or the inlet 38 and outlet 40) may also be equipped with valves.

[0035] The buffer tank 18 has an actionable fluid barrier 42, e.g. a piston, partitioning the buffer tank 18 in two chambers 44, 46 (chamber 44 is not visible in Fig. 2 since the piston 42 is at an extremal position). Chamber 44 may comprise unpressurized fluid originating from the system application and chamber 46 may comprise pressurized fluid for the system application. The piston 42 may be actioned through a piston rod 48 by an external driving force, e.g. provided by an hydraulic piston drive.

[0036] The pressurizer tank 20 comprises a movable fluid barrier 50, e.g; a piston, partitioning the pressurized tank 20 in two chambers 52, 54 (here also chamber 52 is not visible in Fig. 2 since he piston 50 is at an extremal position). In contrast with the piston 42 of the buffer tank 18, the piston 50 of the pressurizer tank 20 is not actionable by an external force but only movable through internal forces present in the pressurizer tank 20, e.g. pressure difference in the two chambers 52, 54 of the pressurizer tank 20.

[0037] In the present embodiments, the fluid barriers 42, 50 are pistons. However, other fluid barriers are also contemplated.

[0038] The pressurizer tank 20 further comprises a heat exchanger 56 so as to perform an (isochoric) heat addition to the fluid contained in chambers 52, 54. Heat is supplied from an external heat source (indicated by a Q in Fig. 2). The heat is transferred to the chambers 52, 54 via a working fluid flowing through heat exchanger tubes embedded in the pressuriser tank walls. Of course, other ways of performing the (isochoric) heat addition to the fluid contained in chambers 52, 54 are contemplated. It has however been found that using only one heat exchanger incorporated in the walls of the pressurize tank 56 drastically reduces system size as well as system costs.

[0039] The connections between the chambers 44, 46, 52, 54 are provided by the lines 22, 24, 26, 28, in particular:

• an upper (first) supply line 22 fluidically connecting the first buffer tank chamber 44 and the first pressurizer tank chamber 52;

• a lower (second) supply line 24 fluidically connecting the first buffer tank chamber 44 and the second pressurizer tank chamber 54;

• an upper (first) discharge line 28 fluidically connecting the second buffer tank chamber 46 and the first pressurizer tank chamber 52; and a lower (second) discharge line 26 fluidically connecting the second buffer tank chamber 46 and the second pressurizer tank chamber 54.

[0040] Each of the chambers 52, 54 of the pressurizer tank 20 may be filled with low-pressure fluid from the buffer tank 18 (first buffer tank chamber 44) via the upper supply line 22 and the lower supply line 24, respectively (as shown in Fig. 2). The piston 50 of the pressurize tank 20 is moved by the fluids entering or exiting the pressurize tank 20. High-pressure fluid maybe transferred from the first pressurizer tank chamber 52 or second pressurizer tank chamber 54 via the lower and upper discharge lines 28, 26, respectively, to the second buffer tank chamber 46, as indicated in Fig. 3.

[0041] For the sake of clarity, the reference signs indicated in Fig. 2 are not repeated in the following figures, except for those which are not indicted in Fig. 2.

[0042] In a first state, as shown in Fig. 4, the buffer tank, in particular the second buffer tank chamber 46, is filled with high-pressure fluid and the piston 42 is at a top position. Low-pressure fluid enters the buffer tank 18, in particular the first buffer tank chamber 44, via the inflow line 14 and corresponding inlet. High- pressure fluid is released to the system application via the outflow line 16 and corresponding outlet. Both valves -from inflow and outflow lines and/ or inlet and outlet- are open. All other valves between the buffer tank 18 and the pressurizer tank 20 are closed. The pressurizer tank 20 is filled with low-pressure fluid and the movable piston 50 is in top position. Hot fluid from the external heat source flows through the fluid channels of the pressurizer tank 20 and transfers thermal energy to the fluid in the pressurizer tank 20.

[0043] During operation, as illustrated in Fig. 5, the piston 42 of the buffer tank 18 moves down as low-pressure fluid from the system application flows in the first buffer tank chamber 44 and high-pressure fluid flows out of the second buffer tank chamber 46 in the system application 10. An external driving force provided by a driving device controls the movement of the piston 42 by pushing or pulling on the piston rod to which the piston 42 is attached. Any existing driving device may be used, e.g. a hydraulic device or an electric motor. In the pressurizer tank 20, the fluid is trapped because all its connection valves are closed. The (isochoric) heat addition leads to a pressure increase of the fluid contained in the pressurizer tank 20. [0044] In Fig- 6, the buffer tank 18, in particular the first buffer tank chamber 44, is completely filled with low-pressure fluid and the piston has moved all the way down to the bottom. In the pressurizer tank 20, the fluid is now pressurized.

[0045] As depicted in Fig. 7, in next step, the valves of the inflow line and the outflow line are closed. The valves 30, 34 of upper supply line 22 and lower discharge line 26, respectively, are opened. The fluid contained in the buffer tank 18 and the pressurizer tank 20 are exchanged. The piston 50 of the pressurizer tank 20 is located in top position, thus, the upper supply line 22 is used for top injection and the lower discharge line 26 is used for bottom discharge. In other words, fluid contained in first buffer tank chamber 44 is transferred in the first pressurizer tank chamber 52 and fluid contained in the second pressurizer tank chamber 54 is transferred in the second buffer tank chamber 46.

[0046] Fig. 8 shows the fluid exchange between the buffer tank 18 and the pressurizer tank 20. The piston 42 in the buffer tank, driven by the external force, moves upwards, pushing the low-pressure fluid though the upper supply line 22 into the pressurizer tank 20. The piston 50 in the pressurizer tank 20 moves downwards until all high-pressure fluid is flown into the buffer tank 18.

[0047] After the fluids of buffer tank and pressurizer tank are exchanged, the piston 42 in the buffer tank 18 has moved all the way to the end (see Fig. 9) and the piston 50 of the pressurizer tank 20 is in its bottom position - the exchange of the fluid is stopped.

[0048] In a next step, as illustrated in Fig. 10, the valves 30, 34 of the upper supply line 22 and the lower discharge line 26 are closed. The buffer tank 18 is reconnected with the system application: inflow line 14 and outflow lines 16 are opened by the respective valves.

[0049] It is worthwhile noting the compression system is now in the same state as initially, see Fig. 4, except in that the piston 50 of the pressurizer tank 20 is in an opposite location, i.e. at the bottom of the pressurizer tank 20.

[0050] The fluid in pressurizer tank 20 is heated by the external heat source and the pressure rises. The buffer tank 18 supplies the system application with high- pressure fluid via the outflow line and collecting low-pressure fluid via the inflow line as can be seen in Fig. n.

[0051] In Fig. 12, the piston 42 has reached its extremal position. The first buffer tank chamber 44 is filled with unpressurized fluids.

[0052] In a next step, as depicted in Fig. 13, the buffer tank 18 and the pressurizer tank 20 are connected via the lower supply line 24 and the upper discharge line 28 by opening the respective valves 32, 36.

[0053] While contents of the buffer tank 18 and the pressurizer tank 20 are exchanged, the piston 42 of the buffer tank 18 moves upwards with increasing amount of high-pressure fluid being injected from the bottom via the upper discharge line 28. Also, the piston 50 of the pressurizer tank 20 moves upwards since the low-pressure fluid is injected via the lower supply line 24, as shown in Fig. 14.

[0054] As shown in Fig. 15, the fluids of the buffer tank 18 and the pressurizer tank 20 have been fully exchanged. Both pistons 42, 50 are in top position. When the lower supply line 32 and upper discharge line 28 are closed and the inflow and outflow lines 14, 16 are opened to the system application, a full cycle has been performed.

[0055] In an embodiment, the tanks 18, 20 are thermally insulated. In an embodiment, at least one of the lines 22, 24, 26, 28 are thermally insulated. Typical thermal insulation coefficients may be comprised in the range from 0,02 to 0,057 W/(m*K).

[0056] In an embodiment, the valves are solenoid valves.

[0057] In an embodiment, the heat carried out by the working fluid in the heat exchange originates from a waste heat source.

[0058] In an embodiment, the fluid may be a gas, a liquid or a combination thereof. Also, one or more phase transitions are not excluded during the cycle.

[0059] It is worthwhile mentioning that the sizing of buffer tank and pressurizer tank (e.g. volume) depend on the desired buffer time (amount of fluid in buffer tank), the available heat flow and the required pressure difference. The specific parameters depend on the individual application and the tank volume is chosen accordingly. It will be appreciated that the present invention allows for a wide range of applications, since virtually no restriction exist as to the physical state of the fluid nor the dimensioning of the compression system itself.

[0060] Also, in a preferred embodiment, the driving applied to the piston 42 is periodic. Even more preferably, the driving that is applied is asymmetric periodic driving. The piston 42 may go faster on the way up than on the way down, so that the compression system has low interruption time wherein it can’t supply the system application with pressurized fluid. For example, the piston 42 may go up between 2 and 20 times, preferably between 5 and 10 times faster than it goes down.

[0061] The periodicity of the driving is typically comprised in the range from 10 Hz to 100 Hz.

[0062] The operation of at least one of the valves and the driving device driving the piston 42 may be controlled by a controller.

[0063] The controller can be implemented with a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a programmable logic controller (PLC) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The controller may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, multicore processors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Programmable logic controller (PLC) as Feldbus or Profibus are preferred.

[0064] A computer program product comprising a program for operating a controller connected to the compression system is also contemplated. The program may comprise instructions, which, when executed by the controller, causes the controller to carry out the steps of the method as described herein, in particular cause to operate the valves and driving device to perform the full cycle as described herein.

[0065] It is worthwhile noting that in the description, the terms “up”, “down”, “upwards”, “downwards” or the like are used for the sake of clarity and conciseness and also to be in line with the reading of the schematic representation of the figures. Nothing should be implied as to the positioning of the compression device in use. Said terms are merely used for indicating one end and the other (opposite) end of the reservoir (tank) or direction towards these ends.

[0066] While specific embodiments have been described herein in detail, those skilled in the art will appreciate that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.

Claims

1. A compression system for compressing a fluid, comprising: a buffer reservoir comprising first and second buffer reservoir chambers separated by an actionable fluid barrier, the actionable fluid barrier being arranged fluid tight in the buffer reservoir so as to fluidically isolate the first and the second buffer reservoir chambers; a pressurizer reservoir comprising first and second pressurizer reservoir chambers separated by a movable fluid barrier, the movable fluid barrier being arranged fluid tight in the pressurizer reservoir so as to fluidically isolate the first and the second pressurizer reservoir chambers, the pressurizer reservoir further comprising a heat exchanger for exchanging heat with the first and the second pressurizer reservoir chambers; a first supply line fluidically connecting the first buffer reservoir chamber and the first pressurizer reservoir chamber; a second supply line fluidically connecting the first buffer reservoir chamber and the second pressurizer reservoir chamber; a first discharge line fluidically connecting the second buffer reservoir chamber and the first pressurizer reservoir chamber; and a second discharge line fluidically connecting the second buffer reservoir chamber and the second pressurizer reservoir chamber.

2. The compression system according to claim 1, further comprising at least one of an inlet fluidically connected to the first buffer reservoir chamber and an outlet fluidically connected to the second buffer reservoir chamber.

3. The compression system according to any one of claims 1 to 2, further comprising one or more valves arranged for selectively opening or closing the first supply line, the second supply line, the first discharge line, second discharge line, inlet and/ or the outlet.

4. The compression system according to any one of claims 1 to 3, further comprising a driving device for driving the actionable fluid barrier.

5. The compression system according to claim 4, wherein the driving device is configured to apply a periodic driving to the actionable fluid barrier, preferably to apply an asymmetric periodic driving.

6. The compression system according to any one of claims 1 to 5, wherein a period of the periodic driving is comprised in the range from 10 Hz to 100 Hz.

7. The compression system according to any one of claims 1 to 6, wherein the buffer reservoir and the pressurizer reservoir have substantially equal volumes, preferably in the range from 0.005 to 0.83 ^m3-

8. The compression system according to any one of claims 1 to 7, wherein a ratio between the movable fluid barrier diameter and the buffer reservoir height is comprised in the range from 0.002 to 0.002.

9. The compression system according to any one of claims 1 to 8, further comprising a controller for controlling the one or more valves arranged for selectively opening or closing the first supply line, the second supply line, the first discharge line, second discharge line, inlet and/ or the outlet.

10. The compression system according to any one of claims 1 to 9, wherein the first supply line, the second supply line, the first discharge line, second discharge line, inlet and/ or the outlet are thermally insulated.

11. A method for operating the compressing system according to any one of claims 1 to 10, comprising: driving the actionable fluid barrier with the driving device; and exchanging heat with the first and the second pressurizer reservoir chambers.

12. The method according to claim 11, further comprising selectively opening or closing the one or more valves of the first supply line, the second supply line, the first discharge line, second discharge line, inlet and/ or the outlet.

13. The method according to any one of claims 11 to 12, wherein the driving is periodic, preferably the periodic driving is asymmetric.

14. A controller configured to carry out the steps of the method according to any one of claims 11 to 13.

15. A computer program product comprising a program for operating a controller connected to a compression system according to any one of claims 1 to 10, the program comprising instructions, which, when executed by the controller, causes the controller to carry out the steps of the method according to any one of claims 11 to 13.