Method of operating a reverse osmosis plant; reverse osmosis plant

Abstract

A method of operating a reverse osmosis plant and a reverse osmosis plant are proposed, wherein a pressure differential is generated at at least one reverse osmosis membrane of the reverse osmosis plant, wherein the pressure differential is generated at least partly by exploiting natural geographic circumstances, which means that less pressure has to be generated directly for operation, which means that the operation of the reverse osmosis plant is less energy-intensive.

Description

[0001] Method for operating a reverse osmosis system; reverse osmosis system

[0002] State of the art

[0003] The invention is based on a method for operating a reverse osmosis system according to the preamble of claim 1, and a reverse osmosis system according to the preamble of claim 10.

[0004] The conversion of saltwater into purified (drinking) water, particularly through reverse osmosis, has long been state-of-the-art. Drinking water presents a challenge, particularly in regions with high aridity and countries with low purchasing power, which is why there is a need for more cost-effective production processes.

[0005] Reverse osmosis has long been known in combination with energy conversion processes. For example, WO 2014 / 100674 A1 and WO 2020 / 068775 A1 describe power plants that drive reverse osmosis systems. Combinations with downstream energy conversion processes are also known, such as the use of purified water from reverse osmosis for electrolytic water splitting. For example, DE 10 2013 017 914 A1 describes a process for connecting offshore wind farms in which, after upstream desalination of seawater using reverse osmosis, hydrogen is extracted from water by electrolysis, which is then converted into methane for easier transport. The disadvantages of these processes are the high energy costs for reverse osmosis, electrolysis, and transport.A comparable process is also fundamentally based on patent DE 197 14 512 C2, which discloses a maritime power plant. Compared to DE 10 2013 017 914 A1, for example, the maritime power plant has the advantage of utilizing the deep sea pressure for reverse osmosis. The disadvantage of this plant is that it still requires a high level of energy to operate.

[0006] The invention is therefore based on the object of providing a method for operating a reverse osmosis system that overcomes the disadvantages of the prior art and a reverse osmosis system that overcomes the disadvantages of the prior art.

[0007] The invention and its advantages

[0008] The inventive method for operating a reverse osmosis system, with the features of claim 1, and the inventive reverse osmosis system, with the features of claim 10, have the advantage that in the inventive method for operating a reverse osmosis system, wherein a pressure difference is generated across at least one reverse osmosis membrane of the reverse osmosis system, wherein the pressure difference is generated at least partially by exploiting natural geographical conditions, that less pressure needs to be generated directly for operation, whereby the operation of the reverse osmosis system is less energy-intensive. In this context, geographical conditions include, in particular, elevation profiles (mountains, cliffs, sloping coastlines, and the like), ocean currents, tidal range, and comparable conditions.It would be conceivable to use a combination of classic pumps (e.g. flow pumps, displacement pumps) and naturally occurring pressure generation, for example through deep pressure.

[0009] According to an advantageous embodiment of the method according to the invention, the reverse osmosis system is designed as a submarine reverse osmosis system and is permanently or temporarily submerged in an aqueous medium, creating a deep pressure around the submarine reverse osmosis system. The deep pressure is used at least partially to generate the pressure difference across a reverse osmosis membrane of the reverse osmosis system. This has the advantage that part or even all of the pressure required for the operation of the reverse osmosis system is generated by the deep pressure.The high pressure upstream of the reverse osmosis membrane and the low pressure downstream of the reverse osmosis membrane, preferably around atmospheric pressure, then represent a sufficiently high pressure difference for the operation of the reverse osmosis system. It would also be conceivable to use one or more additional pumps to increase the pressure level upstream of the reverse osmosis membrane or further reduce it downstream of the reverse osmosis membrane, thus improving the flow rate or the amount of purified water per unit of time. It would be conceivable to install additional prefilters upstream of the reverse osmosis system so that pre-purified water is fed into it, thus protecting the reverse osmosis membrane.In this context, it would also be conceivable that the flow direction within the reverse osmosis system could be reversed, so that the inlet of a reverse osmosis system could be swapped with the outlet for the enriched brine, thereby making it possible to flush out pre-filters and the like. It would also be conceivable for the reverse osmosis membrane to be installed in a sinking body that is lowered from the surface of a body of water into the water. This sinking body is filled with air. At sufficient water depth, the prevailing depth pressure causes water to flow through the reverse osmosis membrane into the interior of the sinking body, where it is cleaned, and the sinking body is then brought back to the surface. In this regard, it is conceivable that the depth pressure is at least as high as the working pressure required for the reverse osmosis membrane to function.In this context, it would be conceivable for the reverse osmosis system to be submerged at a depth where the pressure at depth (e.g. just under 55 bar at a depth of 550 m) is higher than the pressure required (e.g. 50 bar) for the operation of the reverse osmosis membrane. In this regard, it would be conceivable for the pressure at depth and / or the selected membrane to be coordinated with one another and thus have a correspondingly ideal pressure difference so that an optimal filtration speed of the reverse osmosis membrane is achieved. It would also be conceivable for the pressure upstream of the reverse osmosis membrane to be further increased by pumps or similar. In this sense, it would also be conceivable for the pump power to be applied mechanically and / or by leg power (bicycle or gear pump).The overall process would consist of pre-purification, particularly on the beach or at any depth of the sea, supplying pre-purified water to the reverse osmosis system through a container and / or a hose and / or piping system, and converting the salt water or pre-purified water into purified water.

[0010] According to an additional advantageous embodiment of the method according to the invention, the reverse osmosis system is operated at least partially on and / or in a body of water with a tidal range and / or a current, wherein at least one floating body with at least one piston detachably or permanently attached thereto is used to generate a piston pressure, wherein this piston pressure is used at least partially to generate the pressure difference across a reverse osmosis membrane of the reverse osmosis system. This has the advantage that, due to changes in the water level, at least one piston plunger is pushed in or pulled out to generate piston pressure, which in turn can increase the pressure upstream of the osmosis membrane. This in turn simplifies pressure generation during operation of the reverse osmosis system and thus also allows simple operation on land or at shallow sea depths when combined with the prevailing deep water pressure.It would be conceivable for a floating body with a large surface area and a high weight to be attached detachably or permanently to a piston or its piston, and for the piston to be pushed down by the weight of the floating body when the water level falls and otherwise pulled out when the water level rises. In this sense, a body of water can be a natural or artificial river, lake or sea. It would also be conceivable for water to be pushed from a body of water into an artificial or natural basin due to changes in water level, thereby increasing the natural water level changes caused, for example, by the tidal range. It would also be conceivable for the surface area of ​​the floating body (and thus of the piston head) to be larger than the surface area of ​​the lower piston piston, thereby increasing the pressure on the piston generated by the weight of the floating body, similar to a piston pump.According to an additional advantageous embodiment of the method according to the invention, filtered water is produced by means of the reverse osmosis system and the filtered water is transported to an end user and / or a distribution point, wherein the filtered water is transported by pressure and / or by at least one buoyancy body. This has the advantage that the purified water can reach the user as a product of reverse osmosis. It is conceivable that the pressure behind the reverse osmosis membrane is higher than atmospheric pressure and can be used to distribute the purified water produced. It is conceivable that in the case of a submarine reverse osmosis membrane, the purified water is passed on through a pipe system or collected in containers that can rise to the surface by means of buoyancy bodies.It would also be conceivable for the buoyancy bodies in the form of gas containers to be permanently connected to the container, into which at least some of the purified water is introduced, and to then be taken down again when the container is lowered from the sea surface.

[0011] According to an advantageous embodiment of the method according to the invention, at least one buoyancy body is filled with at least one gas, preferably at least partially with hydrogen or oxygen. This has the advantage that gases expand during ascent and can thus accelerate the ascent process. It would be conceivable for at least one buoyancy body to be made either of an expandable material, which expands as the buoyancy body ascends due to the lower external pressure with the expanding gas inside, or of a pressure-resistant material, which relatively limits the expansion of the gas and thus the buoyancy.It would also be conceivable for the buoyancy bodies to release gas to slow and / or limit buoyancy, as the increasing buoyancy is counteracted by an ever-decreasing water column and thus by the force of gravity, and the gas cylinders rising from the depths thus continually accelerate their ascent. In this regard, it would be conceivable that during the ascent, a depth gauge would determine the depth in relation to time, from which the ascent rate would be calculated, and that gas would be released from at least one gas cylinder to regulate the speed during the ascent, which in turn would slow the ascent. In this sense, it would be preferable for oxygen to be released.

[0012] According to an advantageous embodiment of the method according to the invention in this regard, at least one gas, preferably hydrogen and / or oxygen, is generated via electrolysis. The electrolysis is preferably carried out at the site of the reverse osmosis or in relative proximity to it, which has the advantage that the gases do not have to be transported over a long distance to the buoyancy bodies. It would also be conceivable, however, for the electrolysis and reverse osmosis to be carried out at different sea depths and for the buoyancy bodies to be filled at the site of the electrolysis and then, for example, already ascending, moved to the reverse osmosis system or to move and pick up a container of purified water there and transport it further. It would also be conceivable for the purified water obtained from the reverse osmosis to be used for the electrolysis.In this regard, it would be conceivable for a portion of the purified water to be converted into hydrogen and oxygen, and for the gases to be used to transport another portion of the purified water to the sea surface. Depending on the efficiency of the electrolyzers and reverse osmosis systems used, the amount to be converted and transported can be adjusted. It would also be conceivable for the purified water from at least one reverse osmosis system to be transported using a container between this reverse osmosis system and at least one electrolyzer.

[0013] According to an advantageous embodiment of the method according to the invention, the electrolysis is operated at least partially using electrical energy generated by at least one energy converter that converts mechanical energy into electrical energy, such as a dynamo, a propeller, or the like, whereby the electrolysis can be operated in an energy-efficient manner. It is also conceivable, of course, to use a mixed supply of the electrolyzer using electrical energy produced by at least one energy converter and electrical energy from another source, such as an osmosis or wave power plant or a renewable source such as sunlight or wind power, for the electrolysis. It would also be conceivable to reduce the ascent rate by connecting energy converters that convert mechanical energy into electrical energy (such as dynamos or water propellers).It would also be conceivable for at least one container filled with pre-purified water and / or air at the sea surface to be transported along at least one guide to at least one submarine reverse osmosis plant and / or for at least one container filled with purified water to be transported to at least one electrolyzer for electrolysis. It would also be conceivable for the container to sink, at least partially, under its own weight, to the submarine reverse osmosis plant. It would also be conceivable for the guide to be a rope, a pipe, a hose, a cable, or the like. It would also be conceivable for at least one guide to be attached to a beach, a platform floating in the sea, or at least one ship.In this regard, it would be conceivable for the guide to lead from the electrolyzer back to the sea surface, where it is either attached to a beach, a platform floating in the sea, or at least one ship, or from a beach, a platform floating in the sea, or at least one ship to the reverse osmosis system. It would also be conceivable for at least one energy converter to be attached to at least one container, which can slide along the at least one guide and convert the mechanical energy generated by sliding along the at least one guide into electrical energy. In this sense, it would be conceivable for the energy converter to be a dynamo or another electrical generator that utilizes induction effects.In this sense, it would also be conceivable for at least one guide to contain a conductive component that transmits electrical energy generated by at least one energy converter to at least one electrolyzer. It would be conceivable for the energy to come from a source such as an osmosis or wave power plant, or a renewable source such as sunlight or wind power.

[0014] According to an advantageous embodiment of the method according to the invention, the energy converter is moved from an elevated position with high potential energy, preferably by weight, to a position with lower potential energy, while simultaneously generating electrical energy, whereby the naturally occurring weight can be used to generate energy. In this context, it would be conceivable for a means of transport to be moved down a mountain, slope, or the like, and for energy converters to convert the kinetic energy into electricity. These could be, for example, dynamos that are moved along a surface, as well as propellers that convert the draft into electrical energy, or the like. It would also be conceivable for tracks to be laid on a mountain, slope, or the like.In this sense, it would also be conceivable for the tracks to be laid reversibly there, whereby it would be particularly conceivable for the tracks or track elements to be designed to be rollable and easy to roll out and back up again. It would also be conceivable for the means of transport to transport rubble, sediment, snow, ice, water and / or other transportable goods downhill from a position with high potential energy, such as a mountain peak. In this sense, a change in temperature, for example from a mountain peak to the valley, could in particular cause a change in the state of matter, whereby this would preferably be the melting of snow and / or ice, which could then, now as water, be used in a reverse osmosis system as water to be purified, or could be used for water splitting in an electrolyzer.

[0015] According to an advantageous embodiment of the method according to the invention, the weight force is increased by an additional weight body and the energy converter moves more quickly into a position with lower potential energy. It would be conceivable for the movement of at least one container towards the (sea)bed to be accelerated by additional weights and / or a drive and / or for the movement of at least one container towards the (sea) surface to be accelerated by a drive. In this sense, it would be conceivable for the drive to be powered by a motor, in particular an electric motor and / or combustion engine. It would also be conceivable for additional weights, such as sandbags, to be used during the movement towards the (sea)bed to achieve faster sinking.Furthermore, it would also be conceivable to carry compressed air cylinders, which could be introduced into a separate gas container to generate additional buoyancy. The reverse osmosis system according to the invention, which is designed to carry out a method according to one of claims 1 to 9, has the advantage over the prior art that it operates efficiently and has reduced energy requirements.

[0016] It would also be conceivable for pre-purified water to be transported from the sea surface to at least one reverse osmosis system via a pressure-resistant hose and / or pipe system, and / or for purified water to be transported from at least one reverse osmosis system to at least one electrolyzer. It would also be conceivable for hydrogen and / or oxygen to be transported toward the sea surface via a hose and / or pipe system.An exemplary device could consist of at least one reverse osmosis system and at least one electrolyzer, and at least one reverse osmosis system and at least one electrolyzer would be directly or indirectly connected to one another in such a way that a portion of the purified water produced by at least one reverse osmosis system from salt water and / or pre-purified water can be transported to at least one electrolyzer, which produces hydrogen and oxygen therefrom, and gas containers are reversibly connected to at least one electrolyzer, which are connected to it in such a way that the hydrogen and oxygen produced can be fed separately into the gas containers, or the hydrogen or oxygen produced can be fed into a gas container, whereby the gases can be collected and then used to transport the container.It would be conceivable for the gas cylinders to be permanently connected to the tank, which can be filled with pre-purified water or salt water. It would also be conceivable for at least one reverse osmosis system and at least one electrolyzer to be connected via a guide and / or a pressure-resistant hose and / or piping system.

[0017] It's conceivable that the resulting products, especially hydrogen and oxygen, could be used to generate energy on land. It's also conceivable that the purified water could be used as drinking water.

[0018] Further advantages and advantageous embodiments of the invention can be found in the following description, the claims and the drawings. Drawings

[0019] Preferred embodiments of the subject matter according to the invention are illustrated in the drawings and are explained in more detail below.

[0020] Fig. 1 is a schematic representation of the method according to the invention for operating a reverse osmosis system at two sea depths,

[0021] Fig. 2 is a schematic representation of the method according to the invention at a sea depth and

[0022] Fig. 3 a schematic representation of the method according to the invention at two sea depths with hose and / or pipeline system

[0023] Description of the embodiments

[0024] Fig. 1 shows a schematic representation of the method according to the invention for operating a reverse osmosis system at two sea depths. On the beach 1, seawater or salt water is first pre-cleaned in a pre-cleaning station 2, thus obtaining pre-cleaned water which is free of suspended matter and already has a lower salt content than the original salt water. This pre-cleaned water is filled into a pressure-resistant container 3. The container 3 then sinks from the sea surface 4 into the sea 5 to a reverse osmosis system 6, to which it is coupled. As it slides down, the container 3 is guided along a guide 7, to which it is attached via fastening means 8. The fastening means 8 allow the container 3 to slide along the guide 7.Energy converters 9, in this case dynamos, come into contact with the guide 7 and generate electrical energy from the kinetic energy of movement, which is then passed via the guide 7, which has a conductive component in the form of a built-in cable, to the reverse osmosis system 6 and then to an electrolyzer 10. The pre-purified water can be pressed from the tank into the reverse osmosis system by the depth pressure in the tank 3, which, for example, has a lockable pressure plate that can be returned after the pre-purified water has been pressed out, while simultaneously being compressed, for example, to just under 50 bar at a sea depth of -500 m. It would also be conceivable for the water to be purified to be forced out by pumps or mechanically. In the reverse osmosis system 6, the pre-purified water is then pressed through the filter membrane, behind which a pressure of approximately 1 bar is present.The concentrated brine is flushed out into the sea 5 and the purified water is filled back into the tank 3 and / or another comparable tank. A check valve at the outlet for the concentrated brine prevents the incoming water to be purified from having to work against the depth pressure. During the filtration process, the concentrated brine and the purified water flow out of the reverse osmosis system 6, so that the pressure in it decreases and is rebuilt by the incoming water to be purified. The tank 3 filled with purified water sinks, again along a guide 11, down to the electrolyzer 10. The tank 3 docks onto the electrolyzer and directs a portion of the purified water into the electrolyzer 10, in which the gases oxygen and hydrogen are extracted from the purified water. In principle, it would also be conceivable for the electrolyzer 10 to be operated with salt water.The oxygen and hydrogen gases are collected in separate gas containers 12. These expand and generate additional buoyancy, which allows the container 3 to be moved back up to the sea surface 4. At a withdrawal point 13, both the purified water from the container 3 and the hydrogen and oxygen gases from the gas containers 12 are withdrawn. In principle, it would of course also be conceivable to omit the pre-cleaning step and have the container 3 filled with air sink to the reverse osmosis system 6, using seawater for the reverse osmosis process. It would also be conceivable to use different containers 3 for the different transport steps.It would be conceivable for a second container to be attached to the container 3, which takes up air that was present in the container 3 and is forced out by filling it with purified water. In this regard, it would be conceivable for the container to be an expandable gas container that also generates buoyancy during ascent.

[0025] Fig. 2 shows a schematic representation of the process according to the invention at a sea depth in which the electrolyzer 10 is directly connected to the reverse osmosis system 6.

[0026] Fig. 3 shows a schematic representation of the method according to the invention at two sea depths with a hose and / or pipe system as an alternative embodiment. Accordingly, it would be conceivable for a hose and / or pipe system 14 to transport pre-purified water from beach 1 to the reverse osmosis system 6, whereby the pre-purified water could be compressed by the depth pressure so that it arrives there with the pressure required to operate the reverse osmosis system 6, for example, 50 bar. In this case, the container 3 would sink to the reverse osmosis system 6, filled with air, and there be filled with purified water.

[0027] In this regard, it would be conceivable that part of the purified water is transported back to the sea surface 4 via a hose and / or pipeline system 14.

[0028] In another embodiment, a heavy container 3 (less expensive than a sphere), e.g., a steel barrel, which is pressure-resistant up to approximately 55 bar (even when filled with surface air), is lowered to an osmosis membrane depth of over -550 m (the pressure of purified seawater here is approximately 55 bar) or sinks to this depth and connects to the reverse osmosis system 6. Here, its internal air volume fills with water purified by the osmosis membrane. This container 3 then sinks along the almost vertically downward guide 11 to the deepest possible bottom (suitable location selection). Gravity is used to produce as much electrical power as possible through energy converter 9. The electrical power is used to produce hydrogen and oxygen, which are each fed into separate gas containers 12 (elastic, up to the pre-built maximum size).

[0029] The energy converters 9, in this case dynamos, utilize gravity and buoyancy during descent and ascent to generate electrical power induced by movement. Electrolysis then follows to further satisfy the power generation objective of the system's design.

[0030] The two gases hydrogen and oxygen produced at the bottom by electrolysis then - filled in separate gas containers 12 - pull the container 3 filled with purified water up to the beach or to a ship or to a platform for emptying.

[0031] For round-trip production, a guide 3 consisting of two bendable inner tubes for gas and / or water transformation can be suspended on the beach 1 or from there with a boat or between boats in a U-shape with a depth (depending on the module specification) with its tip at, for example, - 550 m.

[0032] On beach 1, or on a ship, or on a platform, the saltwater to be desalinated is first pre-treated, depending on access. After pre-treatment, the pre-treated water is piped through at least one line to reverse osmosis system 6.

[0033] The gas containers 12 consist, for example, of a flexible volume that can be limited by a metal (foil) shape (overpressure-storing, "water-expressing"). This volume increases during gas filling due to the rise in relation to the external pressure in relation to the internal pressure.

[0034] Since the container 3 is already denser when filled with air, i.e., heavier than the surrounding seawater, it sinks further when filled with purified water, further compressed and weighted down. Dynamos or energy converters 9 can be activated again, which utilize the sinking force / movement of the body to generate electrical current. It would also be conceivable for the reverse osmosis system to be designed in such a way that the inlet for the water to be purified can be swapped with the outlet for the concentrated brine, making it possible to rinse the reverse osmosis membrane and any prefilter by changing the flow direction.

[0035] In a further embodiment, a container is lowered to a depth below the sea level, which generates sufficient pressure to force water, in particular pre-purified water, through a reverse osmosis membrane, behind which a normal pressure of approximately 1 bar preferably prevails. The reverse osmosis membrane is installed in the container and automatically begins filtering the water at the appropriate depth, whereby the space behind the membrane is successively filled with purified water, which leads to the pressure behind the membrane increasing and, consequently, the production of purified water eventually coming to a halt. The container can then be brought back to the sea surface, for example using gas containers, the buoyancy of which moves the container to the sea surface.The gas containers can be filled, for example, with gases produced in the depths or on land, such as hydrogen and oxygen, which were produced via a water splitting reaction in an electrolyzer, in particular from a portion of the purified water produced.

[0036] In a further embodiment, a means of transport is first placed in a position with high potential energy, such as a mountain, with, for example, scree, snow and / or ice. The means of transport is preferably made of a lightweight construction, for example from plastic, aluminum or the like, and preferably runs on rails. These are laid downslope, and in particular are reversibly laid rails that can, for example, be rolled out and later rolled back in. The means of transport can then roll downslope and transport its load into the valley, melting any ice and snow carried along with it. Energy converters attached to the means of transport produce electricity during the movement process, which can be stored or used to electrolyze the water that forms.The gases produced by electrolysis, preferably oxygen and hydrogen, can be collected in gas containers and used to slow the vehicle and, if necessary, transport it more easily back to its starting point. The vehicle can also be moved into a body of water and allowed to sink there. If it is a container, it can be coupled with the methods for operating a reverse osmosis system from the previously described embodiments. Each separate process step can, of course, be freely combined with the other steps.

[0037] All features presented here can be essential to the invention both individually and in any combination with one another.

[0038] Reference number list

[0039] 1 beach

[0040] 2 pre-cleaning stations

[0041] 3 containers

[0042] 4 Sea surface

[0043] 5 Sea

[0044] 6 reverse osmosis system

[0045] 7 Guide

[0046] 8 fasteners

[0047] 9 Energy converters

[0048] 10 Electrolyzer

[0049] 11 Guide

[0050] 12 gas tanks

[0051] 13 sampling point

[0052] 14 Hose and / or piping system

Claims

Patent claims 1. A method for operating a reverse osmosis system, wherein a pressure difference is generated across at least one reverse osmosis membrane of the reverse osmosis system, characterized in that the pressure difference is generated at least partially by utilizing natural geographical conditions.

2. A method according to claim 1, characterized in that the reverse osmosis system is designed as a submarine reverse osmosis system and is permanently or temporarily submerged in an aqueous medium, thereby creating a pressure at depth around the submarine reverse osmosis system, wherein the pressure at depth is used at least partially to generate the pressure difference across a reverse osmosis membrane of the reverse osmosis system.

3. A method according to claim 1 or claim 2.characterized in that the reverse osmosis system is operated at least partially on and / or in a body of water with a tidal range and / or a current, wherein at least one float with at least one piston detachably or permanently attached to it is used to generate a piston pressure, wherein this piston pressure is used at least partially to generate the pressure difference across a reverse osmosis membrane of the reverse osmosis system.

4. Method according to one of the preceding claims, characterized in that filtered water is produced by means of the reverse osmosis system and the filtered water is transported to an end user and / or a distribution point, wherein the filtered water is transported by means of pressure and / or by at least one buoyancy body.

5. Method according to claim 4, characterized in that at least one buoyancy body is filled with at least one gas, preferably at least partially with hydrogen or oxygen.

6. Method according to claim 5, characterized in that at least one gas, preferably hydrogen and / or oxygen, was produced via electrolysis. 7, method according to claim 6, characterized in that the electrolysis is at least partially operated by means of electrical energy which is generated by at least one energy converter which converts mechanical energy into electrical energy, such as a dynamo, a propeller or the like.

8. Method for operating a reverse osmosis system according to claim 7, characterized in that the energy converter is moved from an elevated position with high potential energy, preferably by a weight force, to a position with lower potential energy, while simultaneously generating electrical energy.

9. Method for operating a reverse osmosis system according to claim 8, characterized in that the weight force is increased by an additional weight body and the energy converter moves more quickly into a position with lower potential energy.

10. Reverse osmosis system set up to carry out a method according to any one of claims 1 to 9.

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