WO2009090305A1

WO2009090305A1 - Method and plant for producing energy

Info

Publication number: WO2009090305A1
Application number: PCT/FI2009/050030
Authority: WO
Inventors: Mikko Vauhkonen
Original assignee: Oy Fingp-Energy Ltd
Priority date: 2008-01-16
Filing date: 2009-01-15
Publication date: 2009-07-23
Also published as: FI20085685A; WO2009090306A1; FI20085685A0

Abstract

The invention relates to producing energy from the potential energy of a liquid medium (4). According to the invention, the liquid medium (4) is led to a downward-extending downpipe (6) in which the liquid medium (4) flows and/or falls downward; energy is produced from the liquid medium (4) flowing and/or falling in the downpipe (6) by means of two or more turbines (8); the liquid medium (4) is divided and directed from the bottom end of the downpipe (6) to one or more vaporization chambers (10) that are heated; the vapour formed from the liquid medium in the vaporization chamber (10) is led along one or more vent pipes (14) upward to a condensation chamber (16); in the condensation chamber (16) the temperature of the arriving vapour is decreased utilizing the cold energy of water in a natural water system, water area or some other natural water ecosystem in such a manner that the vaporous medium condenses into liquid medium (4); and the liquid medium (4) condensed in the condensation chamber (16) is led back to the downpipe (6).

Description

METHOD AND PLANT FOR PRODUCING ENERGY

BACKGROUND OF THE INVENTION

The invention relates to a method for producing energy according to the preamble of claim 1 and especially to a method for producing energy from the potential energy of a liquid medium. The invention further relates to a plant according to the preamble of claim 9 and especially to a plant for producing energy from the potential energy of a liquid medium.

Prior-art methods, plants, and processes that endeavour artificially to provide water circulation for the production of energy vaporize a circulating medium and recover the energy stored in the vapour with a gas turbine. In other words, such known plants endeavour to produce vapour for a steam turbine. Correspondingly, prior-art methods, plants, and processes for producing energy from the potential energy of water have mainly comprised only water power plants built into natural water systems. In other words, these prior-art solutions are built in existing water systems or waterways by using for instance damming or some other way to direct flow through a turbine of a water power plant.

A problem with the arrangement of the prior art is that the amount of energy produced using a steam turbine and utilizing the potential energy of liquid is very limited. In other words, producing large amounts of energy on an industrial scale in an artificial manner by utilizing the potential energy of liquid and using a steam or gas turbine is very challenging, because it is necessary to produce a great deal of the high-temperature and high-pressure steam or gas to produce significant energy amounts. In addition, it is difficult to achieve a sufficiently high overall efficiency in such an arrangement, because efficient energy production requires the increasing of the pressure of a large amount of steam. Further, these plants are construction- and service-wise difficult to implement and use. In addition, a problem with the prior-art water power plants is that the energy production capacity of these conventional water power plants is very limited and local, because they are mainly governed by natural conditions, that is, what kind of flow rate the water system in question has and what other natural conditions exist that enable the building of the water power plant. In addition, these conventional water power plants significantly affect the flow of the water and thus the entire local ecosystem, whereby they burden the local nature and alter the living environment of the local flora and fauna. BRIEF DESCRIPTION OF THE INVENTION

It is thus an object of the invention to develop a method and plant that solve the above-mentioned problems of the prior art. The object of the invention is achieved with the method according to the characterizing part of claim 1. The object of the invention is achieved with the plant according to the characterizing part of claim 9.

Preferred embodiments of the invention are disclosed in the dependent claims.

The invention is based on providing circulation of a flowing medium in which the potential energy of the medium is utilized in energy production. The liquid medium is allowed to fall downward in a downpipe, and energy is recovered from the falling medium by means of one or more separate turbines mounted consecutively in the downpipe. From the bottom end of the downpipe, the liquid medium is directed to a vaporization chamber where it is heated so that its state changes at least partly from liquid to gaseous or vaporous. Alternatively, the vaporization chamber may be an evaporation chamber where the liquid medium is evaporated by means of heat. The vaporized or evaporated medium rises upward along vent pipes to a condensation chamber provided at the top of the downpipe or above it. In the condensation chamber, the gaseous or evaporated medium is changed back to liquid and again directed to the downpipe. This way, the medium circulates in a closed cycle in which the medium flows substantially vertically in such a manner that its potential energy or the change in its potential energy may be utilized in producing energy. According to the invention, geothermal heat or solar energy may be utilized in the va- porization or evaporation of a liquid medium, whereby the energy for the vaporization of the liquid medium is obtained completely or partly from nature. Correspondingly, it is possible to use cold energy from the water in a natural water system, water area, or other natural water ecosystem, such as sea, lake or river, or alternatively the air to condensate the vaporized or evaporated me- dium back into liquid form in the condensation chamber. Thus, the energy required to alter the state of the medium is obtained completely, primarily or partly from nature outside the system and plant of the invention. The plant is preferably build in a place where water is available year-round from nature and has a lower temperature, preferably significantly lower, than the temperature of the medium circulating in the plant or the condensation temperature of the me- dium, and where, at a reasonable depth from the surface of the earth, geo- thermal heat or solar energy is available for vaporizing the medium.

The plant is preferably built at least partly underground in such a manner that the downpipes and vent pipes extend underground. Alternatively, the location may be undersea or sub-seafloor or underwater or under the bottom of another water system. Further, the plant may also be located in the mountains, inside a mountain or at the side of a mountain, whereby the condensation chamber may utilize the cool waters or cold air of the mountains.

According to what is stated above, the invention provides an artifi- cial water power plant or liquid power plant in which the circulation of a liquid medium simulates the circulation of water in nature. In other words, by means of the method and plant of the invention, energy is produced from the potential energy of a liquid medium in a manner similar to conventional water power plants. The method and plant of the invention provide the advantage that it is capable of producing electric energy in an ecological manner on a large scale and efficiently. Thus, the invention makes it possible to replace the present energy production plants and produce energy in a more ecological manner than today. Returning the liquid back up for recirculation down the down- pipes is a phase in the method and plant which requires energy. The solution of the present invention in which the liquid medium is sprayed or atomizes into drops into the vaporization and/or evaporation chambers permits the vaporization and/or evaporation of the medium in an efficient and quick manner. The thermal energy required for the vaporization and/or evaporation may then be minimized. The liquid is preferably evaporated, because the vaporization of liquid required a considerably larger amount of energy. The rise of the evaporated or vaporized medium in the vent pipes is further promoted by means of suction at the top end and/or blowing at the bottom end of the vent pipe. This minimization of the energy required to lift the liquid upward enables efficient operation of the method or plant.

BRIEF DESCRIPTION OF FIGURES

The invention will now be described in greater detail by means of preferred embodiments and with reference to the attached drawings, in which

Figure 1 is a general view of one operating unit of a plant according to the invention, Figure 2 is a general view of a plant comprising several operating units,

Figure 3 shows an embodiment of a pipe cartridge, Figure 4 shows an embodiment for grouping the pipe cartridges shown in Figure 3, and

Figure 5 is a general view of another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 is a schematic view of an embodiment of the present inven- tion. According to Figure 1, the plant comprises a supply chamber 2 that may be a supply basin, supply container, or the like, in which a medium 4 circulating in the plant can be stored. In other words, the supply chamber 2 may be a completely or partially open basin, but it is preferably a closed container. The plant may comprise in addition to the supply chamber(s) one or more main containers in which the medium 4 may be stored and by means of which the amount of medium 4 circulating in the plant may be adjusted. From the main container, the medium may further be led to the supply chambers 2. The supply chamber 2 has one or more downpipes 6 that extend downward from the supply chamber 4. The downpipe 6 preferably extends vertically downward from the supply chamber 2. The liquid medium 4 in the supply chamber 2 is directed from the supply chamber 2 to the downpipe 6 in which the liquid medium 4 falls or flows downward. As it falls in the vertical downpipe 6, the liquid medium 4 reaches the maximum pressure that may be utilized in energy production. In a downpipe that is at an angle, the speed of the medium 4 remains lower, but in certain embodiments, obliquely downward extending downpipes may also be useful. The plant may also comprise first control means securing the operating process and intended for adjusting the amount of medium 4 directed or flowing into the downpipe 6 and/or for closing the downpipe 6 to prevent the medium 4 from entering it. These first control means may comprise for instance a supply control throttle for regulating the flow of the liquid medium and located at the top end of the downpipe 6 or in the supply chamber 2. In addition, the downpipe 6 may comprise a maintenance pipe mountable to its top end which may be mounted in the downpipe 6 or moved to such a position that it is possible to extend the downpipe 6 above the level of the medium 4 in the supply chamber 2 or above the entire supply chamber 2, whereby no me- dium 4 enters the downpipe 6 and the downpipe can be serviced. The down- pipe 6 may be 0.1 to 5 m in diameter, for instance 2 m. In addition, the length of the downpipe may vary between 10 to 4,000 m, preferably between 10 to 500 m, or 5 to 200 m. In Figure 1 , the length H may thus be 100 to 500 m, for instance. However, the present invention is not limited to the diameter or length of the downpipe 6, but these may vary as necessary according to each application. In addition, it should be noted that in some embodiments, the supply chamber 2 may be left out completely.

The downpipe 6 has one or more turbines 8 preferably mounted one after the other and especially one after the other in the flow direction of the medium. The turbines 8 produce and/or recover energy from the liquid medium 4 falling or flowing in the downpipe 6. The turbines 8 are positioned in the downpipe 6 at predefined intervals in such a manner that each turbine 8 is always capable of receiving the load directed to it by the flowing medium 4 falling from above. Further, these turbines 8 may be designed to withstand the load directed to them by the medium 4 even though one or even three turbines above were out of commission or removed from the downpipe 6. The turbines 8 may be positioned in the downpipe 6 at a distance of 5 to 100 m from each other, for example. In other words, when the turbines 8 are positioned in the downpipe 6 at a distance of 50 or 20 m from each other, in a normal situation, each turbine is capable of receiving the load directed to it by the liquid medium 4 falling 50 m and producing energy from it. Further, each turbine 8 is then dimensioned to be capable of receiving the load directed to it by the liquid medium falling 200 m and producing energy from it, when three consecutive tur- bines 8 above it are out of commission or removed. It should further be noted that the distance between all consecutive turbines 8 need not be the same, but may be different at different points of the downpipe 6. It is also to be noted that the distances between the turbines are not limited to what is stated above, but may vary in the invention according to each application. Alternatively, the downpipe 6 may be divided into two or more branches with one or more turbines 8 in each of them.

The turbines 8 each form an independent unit that may be operated, controlled, serviced, mounted, and removed independent of the other turbines. Alternatively two or more turbines 8 may together form a turbine group that may be operated, controlled, serviced, mounted and removed independent of the other turbines. In other words, each turbine 8 or turbine group can be mounted independently and also operates and is usable regardless of the other turbines 8. Thus, each turbine 8 or turbine group forms its own functionally separate turbine unit. The turbines 8 are preferably mounted in the down- pipe 6 in such a manner that each of them can be installed and removed sepa- rately independent of the other turbines 8. In addition, each turbine 8 or turbine group can be controlled and driven separately, whereby each of them can also be switched on and off or into the operating position and closed position independent of the other turbines 8. Each turbine 8 or turbine group comprises or has connected thereto a separate transmission and generator to produce elec- tricity from the rotational energy of the turbine 8. That is to say that each turbine 8 or turbine group together with the related generator forms an independent electricity production unit that is capable of producing electricity independent of the other turbines 8 or the electricity production units they form. Thus, each downpipe 6 may comprise several turbine generator units that independ- ently produce electricity. With the arrangement described above, in which the turbines 8 or turbine groups and the electricity production units they form are separate and independent of each other, it is possible to produce electricity efficiently and, above all, reliably, since the downpipe need not be taken out of commission due the breakdown or malfunction of one turbine 8, but production can be continued for example until there are at most three malfunctioning or decommissioned turbines after each other; this naturally depends on the dimensioning of the turbines and it is possible to allow less or more malfunctioning or temporarily decommissioned consecutive turbines 8. Consecutive turbines may rotate in the same direction or in opposite directions. Preferably consecutive turbines 8 rotate in opposite directions, whereby the resistance of the liquid medium can be maximized, and at the same time it is also possible to maximize the amount of energy produced by the turbines.

The above turbines 8 may be fixed blade turbines. These fixed blade turbines can be set on idle due to breakdown or some other correspond- ing reason, in which case they rotate freely without producing energy. These fixed blade turbines can be propeller turbines, for instance, or any other prior- art turbines. Alternatively, the turbines may comprise a closing turbine disc with adjustable turbine blades. The location and/or position of the blades can then be altered according to the medium flow through the turbine disc, or the blades can be pulled together or set in the direction of the flow when the turbine needs to be taken out of use. In the following, turbines comprising movable turbine blades are examined in more detail. However, it should be noted that, in the following description, the features that are not directly related to adjustable turbine blades can also be applied to fixed blade turbines. The turbines may further comprise control means for controlling the rotation rate of the tur- bine in accordance with the amount and flow rate of the liquid medium flowing through the turbine. The control means may comprise for instance a gearbox or variator or resistor means. With the resistor means, it is possible to produce energy separately or they may be utilized to optimize the energy produced with the turbine. The control means may further adjust the amount of liquid medium flowing through the turbine. One alternative to implement the turbines is to utilize permanent magnet turbine technology and planetary gearboxes or some other electromagnetic gearboxes. Alternatively, the turbines may also be implemented by using electromagnetic means with which the loss caused by friction and resistance is minimized. In other words, the turbines utilize energy produced by magnetism. With correct placement and arrangement of the turbines, a flow rate of 8 m/s, for instance, or even significantly lower, may be achieved for the liquid medium 4 in the downpipe.

In their operating position, the blades of the turbine 8 essentially cover the entire sectional area of the downpipe 6, whereby an as large propor- tion as possible of the falling medium 4 can be utilized in the production of energy. A sufficient clearing naturally remains between the blade tips of the turbines 8 and the downpipe walls so that the blades in their operating position do not hit the walls of the downpipe 6. If the turbine 8 is damaged or needs to be taken out of use, it is set in a closed state in which the blades of the turbine 8 are pulled together against each other. In this closed state, the turbine 8 only covers part - less than half and preferably less than a third - of the sectional area of the downpipe 6, whereby the liquid medium 4 falling in the downpipe can easily flow past the turbine in its closed state without causing excessive flow resistance or counter-pressure in the downpipe 6. The turbine 8 is also designed to cause an as low a flow resistance as possible in the downpipe 6. The small size of the turbine 8 in its closed state makes it possible to lift each turbine 8 away from the downpipe 6 without needing to remove the turbines 8 above it, since the turbine 8 being lifted away fits in the space between the wall of the downpipe 6 and the other turbines 8 when the other turbines 8 are set in their closed state. The turbines 8 are further mounted in the downpipe 6 in such a manner that they can be removed from the downpipe 6 by lifting. During the lifting, the locking of the turbine 8 opens or its fastening is released and it can be removed simply by lifting the turbine 8 with a robot, for instance. When the turbines 8 are removed, the flow of the medium into the downpipe is interrupted and each turbine or the required turbines are preferably lifted out of the downpipe one by one.

The consecutive turbines 8 in the downpipe 6 can be arranged to rotate in the same direction or in opposite directions. Consecutive turbines 8 preferably rotate in opposite directions, whereby the resistance caused by the kinetic energy of the medium falling in the downpipe 6 can be maximized and the turbine 8 can utilize the medium as efficiently as possible to produce energy. Below or above each turbine 8 or at least some of the turbines, a medium flow rate controller (not shown) can optionally be installed to adjust the amount of medium 4 flowing in the downpipe 6 between the turbines 8 and thus also the pressure and rate of motion in the downpipe. The medium flow rate control- ler may be a throttle or the like that can be utilized as necessary, for instance when one or more turbines 8 above it has been set into the closed state or removed. With the medium flow rate controller, it is thus possible to control the rate and pressure of the medium 4 received by the turbine(s) 8 below or above it. According to the above, it is also clear that a load originating from the weight of the turbines and caused by the liquid medium is directed to the downpipe in addition to its own weight.

From the bottom end of the downpipe 6, the liquid medium 4 is directed to one or more vaporization chambers 10 where the medium 4 is transformed from liquid to vapour or gas. In the embodiment of Figure 1 , the vapori- zation chamber 10 is arranged in flow connection with the bottom end of the downpipe 6 so that the liquid medium 4 can be directed from the bottom end of the downpipe 6 to the vaporization chamber 10 by utilizing the flow rate of the medium 4 at the bottom end of the downpipe 6. The lowest turbine 8 may then be located in the downpipe 6 in such a manner that, after the last turbine 8, the falling liquid medium 4 reaches a velocity of at least 15 m/s, preferably 20 m/s, or even 27.7 m/s, before it arrives at the bottom end of the downpipe 6. The liquid medium 4 flowing at such a considerable speed is directed with the control means 20 to the vaporization chamber 10 by utilizing its own rate of motion. According to Figure 1 , in this embodiment, the flow of the liquid medium 4 is at the bottom end of the downpipe 6 divided into two partial flows by means of a branch pipe 20 in such a manner that each partial flow goes into a sepa- rate vaporization chamber 10. In other words, the embodiment of Figure 1 has two vaporization chambers 10 into which the flow of the liquid medium 4 from the downpipe 6 is divided. However, it should be noted that there may also be only one vaporization chamber 10 or three, four, six, or even more for one downpipe 6. In addition, in an alternative case, two or more downpipes 6 of the same or separate supply chambers 2 also may have a common vaporization chamber 10 in which at least part of the liquid medium 4 of both downpipes 4 is directed,

In the solution of Figure 1 , the diameter of each branch of the branch pipe 20 is preferably smaller than the diameter of the downpipe 6. For instance, a branch pipe 20 with a diameter of 1.4 m in each branch can be connected to a downpipe with a diameter of 2 m. The number of branches in the branch pipe 20 affects the diameter of the branches such that the more branches there are, the smaller the diameter of one branch can be in relation to the downpipe 6. According to Figure 1 , the branch pipe 20 is designed to turn the flow direction of the liquid medium 4 flowing downward from the down- pipe 6 essentially upward by utilizing the above-mentioned rate of the medium 4 at the bottom end of the downpipe 6. In other words, at the bottom of the downpipe 6, the direction of travel of the liquid medium is turned with control means 20, for example a branch pipe, to flow upward. The liquid medium 4 can then be brought to the vaporization chamber 10 such that it flows upward from the nozzles. In other words, the control means 20, in this case branch pipe, of the present embodiment have two tasks. Firstly, the branch pipe 20 sets the downpipe 6 into flow direction with the vaporization chamber 10 so that the liquid medium 4 can be directed from the bottom end of the downpipe 6 to the vaporization chamber 10. Secondly, the branch pipe 20 turns the flow of the liquid medium 4 to run from the bottom upward, whereby the medium 4 also enters the vaporization chamber from the bottom upward. In certain applications, the division of the medium 4 into the branch pipes may be achieved gradually, for instance in such a manner that the different branches of the branch pipe are at different heights.

Maintaining the flow/motion rate of the liquid medium 4 in the branch pipe 20 or other corresponding control means can be facilitated by forcing the liquid medium 4 to a rotating movement at the bottom end of the downpipe 6 below the lowest turbine 8. This rotating movement can be produced for example at the bottom end of the downpipe 6 or in its vicinity by providing grooved vanes (not shown) on the inner walls of the downpipe 6. These vanes may be threaded or spiral in shape, and they protrude from the inner wall of the downpipe 6. It is also possible to provide control means on the branches of the branch pipe 20; these may be vanes on the inner surface of the branch pipe that force the medium 4 to a rotating movement. In other words, these control means forcing the medium 4 to a rotating movement can be arranged on both the branch pipe 20 and bottom end of the downpipe 6, or alternatively on just one of them. When the control means forcing the medium to a rotating movement are arranged on both the downpipe 6 and branch pipe 20, they are arranged to rotate the medium 4 into the same direction so that the flow of the medium does not slow down due to resistance. This rotating movement of the medium helps keep its speed.

The vaporization chamber 10, into which the liquid medium 4 discharges from the branch pipe 20, is in diameter larger than the branch pipe 20. For instance, when the diameter of the branch pipe is 1.4 m, the diameter of the vaporization chamber 10 may be 2 m. The summed total volumes of the branches of the branch pipe 20 correspond to the volume of the downpipe for the purpose of utilizing the downward thrust force of the liquid phase of the downpipe 6. When the liquid medium 4 then enters a wider space, its pressure decreases and, as the pressure decreases, the hydrostatic structure of the liquid is more easily broken, and the liquid medium 4 atomizes more easily into drops. At the same time, when the pressure decreases, no significant counter- pressure is directed to the downpipe. When using the control means that force the liquid medium to a rotating movement, it is possible to improve the atomiz- ing into drops of the liquid medium 4 in the vaporization chamber 10, because in a wider space the rotating liquid medium atomizes more easily into drops, most preferably into liquid mist. Due to the rotating movement, the liquid medium endeavours in the wider vaporization chamber to move towards the heated heat-exchange surfaces. At the top of the branch pipe 20 and/or in the vaporization chamber 10, a nozzle structure may be provided to further sprays the liquid medium or atomize it into drops in the vaporization chamber to an as large surface area as possible or as evenly as possible into the entire vaporization chamber 10 and its heat-exchange surfaces to vaporize or evaporate the medium efficiently. The distance of the vaporization chamber 10 from the lowest point of the branch pipe 20 is shorter than the distance of the lowest turbine in the downpipe 6 from the lowest point of the branch pipe 20. For in- stance, the distance of the lowest turbine from the lowest point of the branch pipe 20 is then 30 m and the distance of the bottom end of the vaporization chamber 10 from the lowest point of the branch pipe 20 is 5 m. In addition, the medium 4 can be supplied to the vaporization chamber 10 along a distance of 10 m upward from the bottom of the vaporization chamber 10. The medium can then be supplied to the vaporization chamber 10 by utilizing the kinetic energy of the medium 4 obtained after the lowest turbine as it falls in the downpipe 6.

The vaporization chamber 10 is heated with heating means 12 that bring geothermal heat from inside the ground to the vaporization chamber 10. In this application, the medium 4 can be either vaporized and/or evaporated in the vaporization chamber 10. The heating means 12 are preferably heating rods with which geothermal heat can be brought to the vaporization chamber 10. The heating rods extend inside the ground deeper than the downpipes 6, for instance 50 to 4,000 m deeper, preferably 200 to 2,000 m deeper, depending on how deep geothermal heat with a sufficiently high temperature can be found. Thus, length D of Figure 1 may be 50 to 2,000 m, for instance, but the invention is in no way limited to length D. The heating rods may extend vertically downward or alternatively obliquely at an angle downward. The heating rods may be made to transfer geothermal heat to the vaporization chamber 10 by conduction and/or by means of a flowing medium. When using a flowing medium, which may be a gas or liquid or whose state may transform from gas to liquid and vice versa in the flow cycle, this flowing medium can be made to circulate in the heating rods 12 in forced convection, when it receives geo- thermal heat in the bottom part of the heating rod and correspondingly transfers heat to the vaporization chamber 10. Alternatively, or in addition to forced convection, it is possible to use mechanical convection provided mechanically, for instance by means of a motor, to circulate the medium in the heating rods. Any flowing substance with good heat transfer capabilities and/or heat capac- ity, such as water, ethanol, an ethanol mixture, or the like, can be used as the flowing medium in the heating rods. In other words, the heating rod 12 in the figure forms a loop in which the flowing medium circulates. There may be several, even dozens of such heating rods, and they surround the vaporization chamber 12. The heating rods 12 may further be provided in such a manner that they transfer geothermal heat to the walls of the vaporization chamber and/or inside the vaporization chamber. In other words, the heating rods 12 may extend inside the vaporization chamber 10, or they are in heat-transfer connection to the inside of the vaporization chamber 10 through the walls of the vaporization chamber 10, or to separate heat transfer means that transfer the heat from the heating rods 12 on to the inside of the vaporization chamber 10. The heating rods may thus form inside the vaporization chamber 10 heat- exchange surfaces, or inside the vaporization chamber 10, they may be separate heat-exchange surfaces that receive thermal energy from the heating rods 12. In addition to this or alternatively, the walls or the vaporization chamber 10 may serve as heat-exchange surfaces. The liquid medium 4 is brought to the vaporization chamber as described above, preferably atomized into drops, in such a manner that it comes into contact with the heat-exchange surfaces, whereby it is efficiently vaporized. Vaporization may also take place in the vaporization chamber 10, when the liquid medium 4 is not in contact with the heat-exchange surfaces, under the effect of the temperature of the vaporiza- tion chamber 10. The aim in this is to distribute the liquid medium in the vaporization chamber 10 with a nozzle as evenly as possible on all heat- exchange surfaces of the vaporization chamber 10 and on the entire width and length of the vaporization chamber, for example along a distance of 2 to 30 m in the vaporization chamber 10. Heat-exchange surfaces are also provided at the bottom of the vaporization chamber 10 in such a manner that the liquid medium 4 that has fallen, flown or otherwise ended up at the bottom may be efficiently vaporized. The kinetic energy of the liquid medium 4 is utilized in bringing it to the vaporization chamber 10 through nozzles as a liquid mist. The nozzle may be built to extend upward from the bottom of the vaporization chamber 10, for instance along a distance of 10 m, in such a manner that it distributes the liquid into the vaporization chamber 10 at the distance of 10 m. Overlapping heat-exchange surfaces may also be provided in the vaporization chamber 10 to extend vertically upward, at an angle upward and/or horizontally. Overlapping heat-exchange surfaces ensure that medium discharging from the top end of the nozzle or in its vicinity also enters into direct contact with the heat-exchange surfaces. The nozzle and heat-exchange surfaces are preferably provided in such a manner that the medium vaporized or evaporated from the heat-exchange surface may flow freely upward. It is further possible that only part of the liquid medium 4 is vaporized/evaporated in the va- porization chamber, and especially in its bottom part, and the rest of the liquid medium is directed to the vaporization chamber as liquid mist, whereby the medium 4 that gasified/vaporized/evaporated below the liquid mist lifts the liquid mist upward as it expands. The flow amount of the liquid directed to the bottom-most part of the vaporization chamber may be adjusted. This may be done for instance by means of micro-nozzles and heat-exchange surfaces pro- vided in the bottom part or at the bottom of the vaporization chamber 10. The supply to the micro-nozzles may be done in the manner of the valves of a combustion engine. In other words, the supply to the micro-nozzles may be discontinuous in such a manner that the gasification of the medium cannot cause a counter-pressure. Therefore, there are preferably a large number of micro-nozzles and they operate discontinuously according to predefined operating cycles. In a preferable case, the heating rods 12 are made to extend to a depth where geothermal heat of at least at 150°C, preferably 200°C, and most preferably 300⁰C is available. Alternatively, the vaporization chamber may be a simple basin or container to which the medium flows from the bottom end of the downpipe 6. The temperature of the vaporization chamber 10 is preferably above 100⁰C, or 200⁰C, or 300⁰C. If necessary, the temperature in the vaporization chamber can be increased to even 400⁰C or above, which ensures a sufficiently quick vaporization of the liquid medium. The temperature of the vaporization chamber 10 can, if necessary, be adjusted according to the amount of liquid medium flowing into the vaporization chamber 10. It should be noted that the invention is not limited to any specific geothermal temperature or vaporization chamber 10 temperature, but the temperature may vary and may be controlled according to the application. In addition, the heat-transmission capability of the soil surrounding the heating rods 12 may be improved by provid- ing liquid or water pockets in the soil. In that case it is possible for instance to force water into the soil in such a manner that the water surrounds the heating rods 12.

If necessary, it is also possible to provide additional heating means 13 into the vaporization chamber 10. The additional heating means 13 may be for instance resistor networks that surround the vaporization chamber 10 in the manner shown in Figure 1. The resistor networks may take the required energy directly from the energy produced by the turbine in the downpipe 6 or from the energy produced by the plant. Alternatively, the additional heating means 13 may comprise heating means of other type that are capable of heating the va- porization chamber 10 and/or the liquid medium 4 that enters it. The additional heating means may also operate on an alternative auxiliary energy or secon- dary energy source, such as geothermal heat. The additional heating means 13 may be provided outside or inside the vaporization chamber 10. Thus, the additional heating means 13 are provided to heat the walls of the vaporization chamber 10 and/or directly the liquid medium 4 led into the vaporization cham- ber 10. Alternatively, or in addition to this, the additional heating means 13 comprise secondary heating means to transfer the thermal energy produced by the heating means 12 inside the vaporization chamber 10. The additional heating means 13 may be used continuously or at times when a great deal of thermal energy is required in the vaporization chamber 10 or when the plant is started up, for instance. These additional heating means may thus be used according to the temperature or target temperature of the vaporization chamber 10 or the process of the plant.

Instead of vaporizing the medium or in addition to it, the medium may also be evaporated. In this context, it should be noted that the vaporiza- tion of a liquid medium requires significantly more energy than its evaporation, so it is advantageous to evaporate at least part of the liquid medium in the vaporization chamber 10.

In an advantageous case, the total volume of one or more vaporization chambers in flow connection with one downpipe is for instance 15fold in relation to the total volume of the downpipe. A pipe cartridge structure, for instance, enables the constructional optimization of the volume of the vaporization chambers and vent pipes. In the vaporization chamber 10, the volume of the vaporizing and/or evaporating medium 4 may increase to be multifold in relation to its liquid form, whereby a lot of space is required so that the vapori- zation of the medium does not cause a counter-pressure in the branch pipe 20 and/or downpipe 6, or it may be minimized.

The high temperature of the vaporization chamber 10 and its heat- exchange surfaces and the decreasing effect of the widening space on the pressure of the medium 4 together make the medium 4 vaporize in the vapori- zation chamber 10. The vaporized medium is guided from the vaporization chamber 10 to a vent pipe 14 which is in flow connection thereto, and in the vent pipe the vaporized medium rises essentially upward, because hot vapour has a physical tendency to rise upward. This vaporized medium is directed upward along the vent pipes 14 until it enters a condensation chamber 16 in which the vaporized medium is transformed back to liquid form and directed along a return fitting 30 back to the supply chamber 2 or alternatively right back to the downpipe 6. There may be one or more vent pipes 14 for each vaporization chamber, and there may be one or more, even 10 or more, of them for one downpipe. If necessary, this rising of the vaporous medium in the vent pipe 14 can be improved by suction means arranged at the top end of the vent pipe and operating on auxiliary energy, for instance. The suction means may be used continuously or at times as necessary. Suction may also decrease pressure in the vent pipe 14 and in certain cases also at least partly in the vaporization chamber 10. By means of the decreased pressure, the energy required by the vaporization of the medium may be reduced, and at the same time, the already vaporized medium remains more safely vaporized and rises up in the vent pipe 14. The suction means may be provided by means of a compressor, for instance, that may serve as a pressure booster. The compressor is located between the top end of the vent pipe and the condensation chamber 16, and preferably above the supply chamber 2. The task of the suction means and compressor is to eliminate the pressure caused by the gasification of the medium in the vaporization chamber and vent pipe and to ensure and promote the upward flow of the liquid medium that is gasified, vaporized and in the form of a mist. In other words, the compressor removes the pressure energy generated during the gasification of the medium from the vaporization chamber and vent pipe in such a manner that the gasification of the medium does not cause a counter-pressure to the counterflow side of the vaporization chamber. The vaporized medium is thus led upward along the vent pipes 14 until it enters the condensation chamber 16, where the vaporized medium is again transformed into liquid form and led along the fitting 30 back to the supply chamber 2. If necessary, the plant may also comprise pressure balancing equipment for balancing and/or lowering the pressure generated by the suction means and the gasification of the medium before the condensation chamber. In accordance with what is stated above, it is essential for the operation and energy requirement of the plant that only a required amount of the medium 4 is vaporized such that the mixture of vapour and liquid mist can be lifted upward along the vent pipes 14 to the condensation chamber 16 in an energy-efficient manner. The gasification and the leading of the gasified medium up the vent pipes is implemented as stated above in such a manner that no condensation or downward flow is possible in the vaporization chamber or vent pipes, In the condensation chamber 16, the vapour risen along the vent pipe 14 is cooled, whereby it condenses back to liquid. The condensation is performed in such a manner that all vaporized medium can be condensed back to liquid with no medium removed from the cycle or remaining in vaporized form. The energy required for this condensation and cooling is cold energy from nature or the environment. In other words, cold energy may be taken from a water system, water area or other corresponding water ecosystem in the environment or created there, such as a river, lake, sea, or underground water system, or from soil, or even air. In certain cases, it is also possible to utilize an artificial water system. The water obtained from nature is brought to the condensation chamber 16 by transport means. In the embodiment de- scribed herein, the energy is limited to cold energy obtained from a natural water system. As shown in Figure 1 , water is brought to the condensation chamber through a pipe 24 from which the water is led inside the condensation chamber 16 along condensation piping 26 and returned to nature, and preferably to the same water ecosystem from which it was taken, along a pipe 28. By means of the above arrangement, the water flowing inside the condensation chamber 16 in the condensation pipe 26 surrenders its cold energy to the vaporized medium which flowed from the vent pipe 14 to the condensation chamber in such a manner that the medium is condensed back into liquid. The heat transfer piping 26 may comprise several parallel pipes and one or more of these pipes may be made to be curved at least along part of its length to maximize the heat transfer surface of the heat transfer piping 26. In other words, in the condensation chamber 16, the heat transfer piping 26 may run in the flow direction or transverse to the flow direction of vapour. Alternatively, the heat transfer pipe 26 may be replaced with some other corresponding heat exchanger, such as a plate or network heat exchanger, or a refrigerant may flow in a closed loop in the heat transfer piping and surrender its cold energy, that is, to which the medium 4 surrenders its thermal energy, whereby the medium condenses back to liquid, and receives cold energy from nature, for instance from water, soil, or air, and thus surrenders heat into water, soil, or air. As shown in Figure 1 , the liquid condensed from vaporized and/or gasified and/or evaporated medium 4 falls to the bottom of the condensation chamber 16, from which the liquid medium flows through pipe fittings to the fitting 30 and on back to the supply chamber 2. The condensation chamber 16 is preferably located level with the supply chamber 2, or above the supply chamber 2, whereby it is easy to return the condensed medium 4 to the supply chamber 2 without separate pumping action. Alternatively, the condensed liquid medium 4 may be returned directly to the downpipe 6, if there is no supply chamber 2, or if this is otherwise preferable. As shown in Figure 1 , the condensation chamber 16 is provided as a pipe-like arrangement that extends in substantially horizontal direction. However, the pipe-like condensation chamber 16 may also be made to extend directly upward or alternatively at an angle obliquely upward. Further, the condensation chamber 16 may also alternatively be provided as some other than pipe-like arrangement as long as the cool water or other cold energy obtained from nature and the gas/vapour/liquid mist from the vent pipe 14 are arranged in a heat-exchange contact with each other so as to condense vapour into liquid. In addition to the cold energy obtained from nature, the energy required for condensing and cooling the vaporized medium is also produced using other energy sources, if necessary. The cold energy may then be taken directly from the electricity production of the plant, or one or more external energy sources may be added to the plant to produce the energy required for condensation. The external energy source may be solar panels, wave power, wind power, or some other energy source, such as thermal energy source or electric energy. The condensation chamber 16 is preferably designed to comprise as much heat-exchange surface area as possible for the condensation of the medium. For instance, the condensation chamber 16 may be divided into blocks in such a manner that the medium can be run inside the condensation chamber into several condensation blocks, in which the heat- exchange surfaces are in the top part or ceiling of the block, where the vaporized medium tends to rise, whereby the condensation takes place through contact between the medium and heat-exchange surface. The condensation chamber 16 may also be furnished with one or more separate condensation spaces (not shown) in which at least part of the vaporized medium may be condensed. These separate condensation spaces may be isolated from the continuous medium flow of the vent pipe and/or from the condensation chamber 16. Such separate condensation spaces may be used in parallel or in series with each other according to the requirements of the used process. The volume of the condensation chamber should be dimensioned sufficiently large to be able to receive the gasified medium from the vent pipe continuously. For instance, when one litre of ethanol is gasified, approximately 1 600 litres of gas is generated, so the vaporization chambers, vent pipes, and condensation chamber should be dimensioned according to the expansion requirement of the medium. If necessary, the condensation chamber 16 and separate condensation spaces may be furnished with reserve containers (not shown) that may be fixed or elastically expanding/contracting. The reserve containers help balance the variations in the total process, in the pressure of the process and/or in the cycle of the medium in the process. In addition, the supply chamber and condensation chamber may be furnished with pressure balancing means that may comprise breathing filters, diaphragms, air and/or liquid locks, for instance. However, the pressure balancing means are preferably provided in such a manner that no medium may flow or leak from them into the environment. According to Figure 1, the supply chamber 2, downpipe 6, vaporization chambers 10, vent pipes 14, and condensation chamber 16, and the related equipment and sub-processes constitute one operating unit. One plant may comprise one such operating unit or several of them side by side, as shown in Figure 2. These operating units may be positioned side by side in contact with each other like in a honeycomb, or alternatively the operating units may be positioned at desired or predefined distances from each other. The positioning of the operating units in relation to each other may vary significantly in different embodiments. According to Figure 2, each supply chamber further forms one cell in a plant where all supply chambers 2 form together a honey- comb structure. Neighbouring supply chambers 2 are preferably in flow connection with each other through intermediate pipes 18, whereby liquid medium may, if necessary, be transferred by pumping, for example, from one supply chamber to another. At the same time, one supply chamber 2 may be closed and isolated from the others and the medium 4 emptied into the neighbouring supply chambers, in which case this closed supply chamber and the down- pipes, turbine, vaporization chambers, vent pipes, and condensation chamber may be serviced. The intermediate pipes 18 are preferably provided in accordance with Figure 1 to the top part of the supply chamber 2 so that they may, if necessary, also serve as overflow fittings when the level in the supply chamber 2 rises too high. It should also be noted that each supply chamber 2 may also comprise two or more downpipes 6, three or more vent pipes 14 and vaporization chambers 10, and two or more condensation chambers 16. In addition, one condensation chamber 16 may be common to two or more supply chambers 2. In Figure 1 , the downpipe 6, branch pipe 20, vaporization chambers

10, vent pipes 14, and condensation chamber 16 are one entity or cartridge that can be installed in a hole or excavation 40 in the ground. Figure 3 shows one such pipe cartridge space 60 that is in the form of a hexagon. Inside the pipe cartridge space 60, a downpipe, branch pipe, vaporization chambers and vent pipes may be installed, preferably in one entity. In addition, in a specific embodiment, the walls of the pipe cartridge space 60 may be utilized to provide vent pipes, for example, in such a manner that in the centre of the pipe cartridge space 60, a downpipe is installed, and the rest of the pipe cartridge space 60 is divided radially from the downpipe into vent pipes. Figure 4 shows an embodiment for grouping adjacent pipe cartridge spaces 60 into a honey- comb. Such a honeycomb produces a reciprocally supporting and spatially efficient structure. A frame or casing may further be provided around the cartridge to house the pipe cartridge formed by the downpipe 6, branch pipe, vaporization chambers 10 and vent pipes. The hole 40 may be quarried and dug in such a manner that between the sides of the cartridge pipes and the hole 40 or alternatively between the sides of the cartridge pipes and casing, there is space that can be filled with water to support the pipes of the cartridge. The hole 40 can further be lined with a sock or other lining that is capable of receiving and keeping the water in the hole 40. In addition, due to its high specific heat capacity, the water in the hole or between the casing and pipes acts as a heat storage, whereby the temperature obtained by the heating means 12 in the vaporization chamber 10 and vent pipes 14 may be maintained and the heating energy requirement lowered. In an embodiment, the heating rods 12 or additional heating means 1 may be provided such that they heat the air or water in the hole 40 between the cartridge pipes or the casing and cartridge pipes. The pipe cartridge may further be provided in such a manner that the pipes 6, 10, 14 completely fill up the volume of the hole 4 or casing/frame. The heating rods may then be positioned in the space/water-space between adjacent pipe cartridges when the pipe cartridges abut each other or are very close to each other, and they may also come directly inside the vaporization cham- bers 10. A pipe cartridge entity may for instance be a reinforced concrete frame, 20 metres in diameter and 500 metres in depth, with a downpipe in the centre and a vent pipe in the centre of each six sectors surrounding it, and the space surrounding it serving as a replacement air channel. The downpipe is then for instance 500 metres in length and 2 metres in diameter, that is, its to- tal volume is over 1 500 000 litres. Six vent pipes with a diameter of 6 metres each, that is, with a volume of approximately 14 000 000 litres each or an overall volume of 84 000 000 litres, are provided around it.

In the plant and method of the invention, the flowing medium may be water, ethanol, an ethanol mixture, or some other corresponding flowing substance that has as a liquid substantially the same potential energy and/or specific weight as water, and/or good vaporization properties, i.e., it vaporizes easily. Ethanol or an ethanol mixture is preferably used as the flowing medium 4, because its potential energy corresponds to that of water, and because vaporizing ethanol is easier and more energy efficient than vaporizing water. In addition, ethanol is a harmless natural product. An advantageous alternative for the flowing medium is an azeotropic ethanol mixture, which is an approximately 96.2 to 98% ethanol. An advantage of the azeotropic ethanol mixture is that it does not become concentrated during changes of state, because its molecular structure remains the same in both liquid and gasified state. An azeotropic mixture is a liquid mixture, in which the composition of the vapour generated from it is the same as that of the liquid mixture.

When the plant is started up before the liquid medium 4 is released to flow in the downpipes, oxygen/air may be removed from the pipes of the plant so as to eliminate the possible ignition/explosion risk of the ethanol va- porizing during heating, for instance. If necessary, oxygen/air in the pipes may be replaced with hydrogen or nitrogen, for instance. Hydrogen or nitrogen may be fed below the lowest turbine, for instance, or oxygen removal and replacement with another substance may be done before starting the supply of the liquid medium when the plant is started up. In different embodiments, the plant may further be furnished with an auxiliary or secondary energy source, such as one or more steam turbines that may be positioned between a vent pipe and condensation chamber, or in the condensation chamber. The auxiliary energy may be used in vapour condensation, liquid vaporization, water pumping, vapour suction upward in a vent pipe, or in some other corresponding operation, or it may simply serve as an addition to the main energy production of the plant. By means of the steam turbine, it is also possible to lower the pressure of the vaporized medium to facilitate the vapour condensation process, because a high temperature of the vaporized medium may increase the pressure significantly. In addition, the en- ergy produced by the turbines 8 may, if necessary, be utilized in increasing and decreasing the temperature of the medium 4. In the condensation cham- ber, it is further possible to utilize conventional heat pump technology, whereby heat may be removed from the medium 4 in the condensation chamber. Heat is further surrendered into cooler soil, for instance, in the depth of 20 m. correspondingly, it is possible to direct a sun beam focused by mirrors into the con- densation chamber or the heat generated by sun beams may be otherwise utilized in increasing the temperature of the medium. Further, if more ethanol than necessary for lifting the ethanol up is vaporized or evaporated in an etha- nol-cycle plant, it is possible to install in the condensation chamber a wind power turbine to slow down the rate of travel, lower the pressure of the vapor- ized and/or evaporated medium to liquefy it and, at the same time, produce electric energy. The turbine may be a wind turbine utilizing kinetic energy or alternatively a steam/gas turbine utilizing pressure.

During the use of the plant, a weight and/or pressure load caused by the weight and liquid flow direction of the downpipe 6, turbines 8, and the liquid medium flowing in the downpipe and branch pipe is directed to the entity formed thereof and endeavours to press this entity downward. To compensate this load, the entity may be structurally supported by anchoring it layer by layer, or to the surrounding soil, or alternatively, when the plant is partly or entirely underwater or sub-seafloor, with floats that direct uplift to this entity. Figure 5 shows an alternative embodiment of the present invention.

The features of the embodiment of Figure 5 and embodiments of Figures 1 to 4 may be freely combined to obtain the required entity at each time. In the embodiment of Figure 5, the liquid medium 4 is led from the supply chamber 2 to the downpipe 6. In this embodiment, the downpipe is not a uniform pipe, as in the embodiment of Figure 1 , but the downpipe 6 consists of two or more pipe sections as shown in Figure 5. In other words, the downpipe 6 is cut in such a manner that the liquid medium 4 flows consecutively through each pipe section of the downpipe 6 until it flows from the lowest pipe section into a collecting basin 51 provided under the downpipe 6. Liquid medium from one or more downpipes 6 may flow into the same collecting basin 51. Each pipe section of the downpipe 6 is furnished with one or more turbines 8 that produce energy by utilizing the potential energy of the medium 4 in the manner of a typical water power plant. Both the pipe sections of the downpipe 6 and the turbines 8 are then arranged in series with each other. Dividing the downpipe into sec- tions is structurally advantageous so that the weight of the liquid phase of the medium along the entire length of the downpipe 6 is not directed to the lowest turbines 8, but at most the weight of the liquid phase of the medium in one pipe section is directed to each turbine 8. According to Figure 5, the downpipe 6 is further furnished with air pipes 57 and 58, of which the pipe 57 feeds replacement air to the downpipe 6 and collecting basin, and the pipe 58 discharges replacement air. Discharge pipe 58 further has a filter that separates the liquid medium 4 from the replacement air being discharged and returns it to the cycle, preferably to the supply chamber 2. Due to thermal energy economics, the replacement air system is preferably negatively pressurized and closed.

Energy is produced by turbines 8 as described above. The turbines are preferably operationally separate, or the turbines 8 are operationally divided into separate turbine groups that comprise two or more turbines 8. Each turbine 8 or turbine group is preferably furnished with a permanent magnet turbine generator and/or planetary transmission to control and optimize the energy production under all conditions and flow rates. The flow rate of the me- dium 4 flowing in the downpipe 6 or its pipe section is adjusted to optimize the operation and energy production of the plant. This may be achieved by adapting the turbines 8 to adjust the flow rate of the liquid medium 4 in the downpipe 6. This in turn may be implemented with Francis-type turbines, for instance. The turbines 8 are adapted to adjust the flow rate of the liquid medium 4 in the downpipe 6 in such a manner that the flow rate is 10 to 1 m/s, preferably 8 to 5 m/s, and most preferably 5 to 1 m/s. The turbines 8 of the plant are arranged to produce energy by utilizing the mass of the liquid medium above the turbine 8 and the pressure directed to the turbine by the mass. In other words, the turbine 8 produces energy from the pressure directed to it by the mass of the liq- uid medium 4 above it by significantly reducing the flow rate of the liquid medium. In the present invention, the operation of the turbines is not based on producing energy mainly by means of the flow rate, or kinetic energy, of the liquid medium, but the turbines 8 attempt to reduce the flow rate of the liquid medium in such a manner that pressure generated by the mass of the liquid phase above it is directed to the turbine 8, and energy is thus produced from the potential energy of the medium 4 by using a slow flow rate of the medium. In other words, the pressure directed by the liquid phase of the medium to the turbine makes it possible to use high transmission rates in the turbine transmission, whereby energy is recovered efficiently even from a slow flow rate. The above-mentioned electromagnetic means, permanent magnet turbine generator and/or planetary transmission of the turbine make this operation of the turbine possible.

From the collecting basin 51 , the liquid medium is led or pumped along a pipe 52 to the vent pipes 14 whose bottom parts form the vaporization chambers 10. The liquid medium 4 is led using the mechanical thrust force of the liquid phase or pumped with pumps 53 to nozzles 54 that spray the medium to the vaporization chamber 10. The nozzles 54 are designed to spray the liquid medium 4 and/or atomize it into drops into the vaporization chamber 10. In other words, the nozzles 54 preferably distribute the medium into a drop mist. The advantage of this is that mist of small droplets has an essentially larger surface area in relation to its mass than mist or spray of large droplets, whereby the evaporation and/or vaporization of the liquid is considerably faster and thus requires less energy. Further, the nozzles 54 are designed to direct the drop-like or sprayed medium to heat-exchange surfaces provided in the vaporization chamber 10, where the vaporization and/or evaporation mainly occurs. However, it should be noted that both vaporization and evaporation takes place. The medium does not entirely vaporize or evaporate on the heat- exchange surfaces, but part of it evaporates or vaporizes at the bottom of the vaporization chamber where it may flow. Thus, the bottom of the vaporization chamber 10 may also be designed as a heated heat-exchange surface. The plant thus comprises heating means 12, vaporization chamber 10 walls and/or specific heat-exchange surfaces 56. The heating means 12 are designed to heat the liquid medium 4 sprayed into or atomized into drops in the vaporization chamber and/or evaporation chamber 10 by means of geothermal energy, solar energy or some other thermal energy, or electric energy. Alternatively, the heating means 12 are designed to heat the liquid medium 4 sprayed or atomized into drops into the vaporization chamber 10 by means of energy produced by one or more turbines 8 or energy external to the plant. The plant further comprises additional heating means 13 for heating the vaporization cham- ber 10 walls and/or specific heat-exchange surfaces 56.

The additional heating means 13 may be a resistor network, for instance, provided to heat the liquid medium 4 sprayed into or atomized into drops in the vaporization chamber and/or evaporation chamber 10 by means of energy produced by one or more turbines 8 or an external energy source of the plant. In the embodiment of Figure 5, there is a blowing effect provided at the bottom ends of the vent pipes 14. The blowing effect is produced by air pumps 55 at the bottom ends of the vent pipes 14, which blow air or some other gas up the vent pipes 14. The blow creates an upward flow in the vent pipe 14, which carries the vaporized or evaporated medium up the vent pipe 14. The air flow rate may be for instance 10 to 100 m/s, preferably 40 to 80 m/s, or more preferably 50 to 70 m/s. This air flow rate is so high that it is also capable of lifting up with it medium that is not evaporated or vaporized but is in small drops. In a preferred embodiment, the liquid medium is essentially evaporated mechanically. In other words, the mechanical evaporation of the medium 4 takes place in three steps: 1 ) mechanical breaking of the liquid phase by spraying or atomizing into liquid mist, 2) necessary heating, and 3) generation of an upward air flow phase into the vent pipes to lift the liquid mist back up above the initial level. The blowing is preferably implemented as a closed blowing-gas circulation along pipes 61. Into this blowing-gas circulation, a filter 62 is further arranged to remove the medium 4 from the blowing gas as shown in Figure 5.

In an embodiment, the structure of the liquid medium is broken with mechanical propulsion pressure in nozzles 56 into such small droplets that in practice the liquid becomes gas. When the size of the drops is sufficiently small, the mass-to-surface ratio makes the liquid mist in practice gas. Mechanical evaporation is an energy efficient manner to return the liquid medium 4 to above the starting level. The decisive factor in the vent pipes is the travel rate, not the temperature of the ethanol mist. When evaporating the medium 4, the temperature changes of the medium need not be big during the process cycle. In other words, the temperature of the medium 4 is raised in the vaporization chamber only enough to evaporate the medium.

From the vent pipes, the evaporated and/or vaporized medium 4 is led to the condensation chamber 16 where the temperature of the medium is lowered so that it condenses back to liquid. In the condensation chamber 16, the temperature of the medium is only lowered enough to make it condense back to liquid. Thus, the process consumes as little energy as possible for the temperature changes of the medium and for lifting the medium from the bottom of the downpipe 6 or collection basin 51 back to the supply chamber 2. The parameters of the plant are dimensioned in such a manner that the energy balance of the plant is always positive, that is, it produces more energy than consumes. In other words, energy is taken from nature to the process or plant; cold energy and/or thermal energy or some other energy that can be transferred to the process.

The plant and method of the invention especially ensure both a structurally and service-wise functional solution with which energy can be produced safely on an industrial scale. Preferably, the plant is located in an area where geothermal heat and/or solar energy is available at a sufficiently high temperature. The method or plant of the invention can be formed into the following three alternative embodiments: an ethanol-cycle plant with only natural cold energy as the external energy source, an ethanol-cycle plant that utilizes both cold energy and thermal energy, and a water-cycle plant that utilizes only thermal energy as the external energy source. Preferably, the cold energy and/or thermal energy can be obtained from nature or produced.

It is obvious to a person skilled in the art the as technology ad- vances, the basic idea of the invention may be implemented in many different ways. The invention and its embodiments are thus not limited to the above examples, but may vary within the scope of the claims.

Claims

1. A method for producing energy from the potential energy of a liquid medium (4), in which method external thermal energy and/or cold energy is utilized in increasing and/or decreasing the temperature of the liquid medium, and the method comprises at least the following steps:

- directing the liquid medium (4) to a downpipe (6) in which the liquid medium flows and/or falls downward;

- producing energy from the liquid medium (4) flowing and/or falling in the downpipe (6) by means of one or more turbines (8); - distributing and directing the liquid medium (4) from the bottom end of the downpipe (6) into one or more vaporization chambers (10) in which the temperature of the liquid medium (4) is increased;

- vaporizing and/or evaporating the liquid medium (4) entirely or partly in the vaporization chamber (10); - directing the vaporized and/or evaporated medium (4) formed of the liquid medium (4) in the vaporization chamber (10) upward along one or more vent pipes (14) to a condensation chamber (16);

- decreasing in the condensation chamber (16) the temperature of the arriving vaporized and/or evaporated medium (4) in such a manner that the medium (4) condenses or transforms back to liquid medium (4); and

- directing the liquid medium (4) condensed in the condensation chamber (16) back to the downpipe (6), characterised in that the method comprises spraying the liquid medium (4) or atomizing it into drops into the vaporization chamber (10).

2. A method as claimed in claim 1, characterised in that the method is implemented as a closed cycle of the medium (4).

3. A method as claimed in claim 1 or 2, characterised in that the used medium (4) is ethanol, an ethanol mixture, an azeotropic ethanol mixture, water, or some other corresponding liquid medium.

4. A method as claimed in any one of the preceding claims 1 to 3, characterised by using geothermal heat, solar energy or some other natural energy to heat the liquid medium (4) in the vaporization chamber (10).

5. A method as claimed in any one of the preceding claims 1 to 4, characterised by decreasing the temperature of the vaporous and/or misty medium (4) arriving at the condensation chamber (16) by means of water from a natural water system, water area, other natural water ecosystem or air or a gas or liquid cooled with cold energy obtained from nature, the temperature of which is lower than that of the vaporous and/or misty medium (4).

6. A method as claimed in any one of the preceding claims 1 to 5, characterised by providing into the vent pipe (14) suction and/or blowing that enhances the rising of the vaporous and/or misty medium (4) upward in the vent pipe.

7. A method as claimed in claim 6, characterised by achieving a flow rate of 10 to 100 m/s, preferably 40 to 80 m/s, or more preferably 50 to 70 m/s in the vent pipe (14).

8. A method as claimed in any one of the preceding claims 1 to 7, characterised by using energy produced by the turbines (8) and/or external energy to the method to heat the medium (4) in the vaporization chamber (10) or condensing the medium (4) in the condensation chamber (16).

9. A plant for producing energy from the potential energy of a liquid, the plant comprising:

- one or more downward-extending downpipes (6) along which a liquid medium (4) flows and/or falls downward;

- one or more turbines (8) provided in each downpipe (6) to recover energy from the liquid medium (4) flowing and/or falling in the downpipe (6);

- one or more vaporization chambers (10) to which the liquid medium (4) is directed from the bottom end of the downpipe (6) for the vaporization and/or evaporation of the liquid medium (4);

- heating means (12) for increasing the temperature of the liquid medium (4) directed to the vaporization chamber (10) for the purpose of vaporizing and/or evaporating the medium;

- one or more vent pipes (14) for directing upward the medium (4) vaporized and/or evaporated in the vaporization chamber (10); and

- one or more condensation chambers (16) for decreasing the tem- perature of and condensing the vaporized and/or evaporated medium directed up the vent pipes (14) into liquid medium (4) and directing the condensed medium (4) back to the downpipe (6), characterised in that the plant also comprises one or more nozzles for spraying the liquid medium (4) or atomizing it into drops into the vaporization chamber (10).

10. A plant as claimed in claim 9, characterised in that the cycle of the medium (4) is implemented as a closed cycle.

11. A plant as claimed in claim 9 or 10, characterised in that the medium (4) circulating in the plant is ethanol, an ethanol mixture, an azeotropic ethanol mixture, water, or some other corresponding liquid medium.

12. A plant as claimed in any one of the preceding claims 9 to 11, characterised in that the heating means (12) are provided to heat the walls and/or specific heat-exchange surfaces (56) of the vaporization chamber (10).

13. A plant as claimed in any one of the preceding claims 9 to 12, characterised in that the heating means (12) are provided to heat the liquid medium (4) sprayed or atomized into drops into the vaporization chamber (10) by means of geothermal heat, solar energy, or some other natural energy.

14. A plant as claimed in any one of the preceding claims 9 to 13, characterised in that the heating means (12) are provided to heat the liquid medium (4) sprayed or atomized into drops into the vaporization chamber (10) by means of energy produced by one or more turbines (8) or by energy external to the plant.

15. A plant as claimed in any one of the preceding claims 9 to 14, characterised in that the plant further comprises additional heating means (13) for heating the walls and/or specific heat-exchange surfaces (56) of the vaporization chamber (10).

16. A plant as claimed in claim 15, characterised in that the additional heating means (13) comprise a resistor network that is arranged at the vaporization chamber (10).

17. A plant as claimed in claim 15 or 16, characterised in that the additional heating means (13) are provided to heat the liquid medium (4) sprayed or atomized into drops into the vaporization chamber (10) by means of the energy produced by one or more turbines (8) or an energy source external to the plant.

18. A plant as claimed in any one of the preceding claims 9 to 17, characterised in that the condensation chamber (16) is arranged to decrease the temperature of the arriving vaporous and/or mist-like medium (4) by means of water from a natural water system, water area, other natural water ecosystem, or air, or a gas or liquid cooled with cold energy obtained from nature.

19. A plant as claimed in any one of the preceding claims 9 to 17, characterised in that the condensation chamber (16) is arranged to de- crease the temperature of the arriving vaporous and/or mist-like medium (4) by means of one or more turbines (8) or an energy source external to the plant.

20. A plant as claimed in any one of the preceding claims 9 to 19, characterised in that the plant comprises suction means and/or blowing means to provide suction and/or blow in the vent pipe (14) to enhance the ris- ing upward of the vaporous and/or mist-like medium (4) in the vent pipe (14).

21. A plant as claimed in claim 20, characterised in that the suction and/or blowing means are arranged to provide a flow rate of 10 to 100 m/s, preferably 40 to 80 m/s, or more preferably 50 to 70 m/s in the vent pipe (14).

22. A plant as claimed in any one of the preceding claims 9 to 21, characterised in that the plant comprises one or more supply chambers (2) from which the liquid medium (4) is led to one or more downpipes (6) and to which supply chamber (2) the liquid medium (4) condensed in the condensation chamber (16) is led.

23. A plant as claimed in claim 22, characterised in that the plant comprises two or more separate supply chambers (2) that are connected to each other so that they may be either isolated from each other or flow connected to each other.