SE541034C2

SE541034C2 - Stirling engine type energy generating system

Info

Publication number: SE541034C2
Application number: SE1650297A
Authority: SE
Inventors: Jan Björkman; Lars Birging; Torbjörn Birging
Original assignee: Zigrid Ab
Priority date: 2016-03-07
Filing date: 2016-03-07
Publication date: 2019-03-12
Also published as: EP3426905A4; EP3426905A1; SE1650297A1; WO2017155452A1; PL3426905T3; EP3426905B1

Abstract

An energy generating system (1) comprising: a main piston system (1'), comprising, a first cylinder (14) comprising a first reciprocatable piston (15), wherein the first piston (15) divides the first cylinder (14) into a first (14a) and second (14b) variable space, wherein the first space (14a) comprises a first gaseous medium (140) a first energy transfer device 30a, a first heat exchanging system (11) , a second cylinder (24) comprising a reciprocatable piston (25), wherein the second piston (25) divides the second cylinder (24) into a third (24a) and fourth (24b) variable space, wherein the third space (24a) comprises a second gaseous medium (240), a second energy transfer device 30b, a second heat exchanging system (21) in fluid connection with the third space (24a), wherein the energy generating system (1) is adapted to synchronize heating of the first gaseous medium (140) with cooling of the second gaseous medium (240) whereby the first and second energy transfer devices (30a, 30b) transfer the kinetic energy from the reciprocating movement of the reciprocatable pistons (15, 25) to an energy generating device (30).

Description

STIRLING ENGINE TYPE ENERGY GENERATING SYSTEM Technical field

[0001] The present invention relates generally to an energy generating system for generating energy from temperature differences of fluids.

Background art

[0002] It is known to use energy generating system for generating energy from temperature differences.

[0003] A drawback of known solutions is their limited ability and feasibility to sufficiently capture surplus of energy in temperature intervals for instance provided by waste heat in industrial processes or natural temperature difference in the environment.

Summary of invention

[0004] An object of the present invention is to alleviate some of the disadvantages of the prior art and to provide an energy generating system which transforms low temperature energy to kinetic energy based on temperature differences. A further object of the present invention is to provide an energy generating system whish transforms energy from temperature differences wherein the warm side if the temperature difference exist below zero degrees Celsius. A further object of the present invention is to provide an energy generating system having a modular design adaptable to need and requirements.

[0005] According to one embodiment of the invention, an energy generating system is provided, comprising: a main piston system, further comprising, a first cylinder comprising a first reciprocatable piston, wherein the first piston sealably divides the first cylinder into a first and second variable space, wherein the first space comprises a first gaseous medium and the second space comprises a fluid medium, a first energy transfer device connected to the first cylinder, a first heat exchanging system in fluid connection with the first space, wherein the first heat exchanging system is adapted to alternately heat and cool the first gaseous medium, whereby pressure in the first space is increased and reduced respectively, a second cylinder comprising a reciprocatable piston, wherein the second piston sealably divides the second cylinder into a third and fourth variable space, wherein the third space comprises a second gaseous medium and the fourth space comprises a fluid medium, a second energy transfer device connected to the second cylinder, a second heat exchanging system in fluid connection with the third space, wherein the second heat exchanging system is adapted to alternately heat and cool the second gaseous medium, whereby pressure in the third space is increased and reduced respectively, wherein the energy generating system is adapted to control heating of the first gaseous medium substantially simultaneously with cooling of the second gaseous medium and conversely cooling of the first gaseous medium substantially simultaneously with heating of the second gaseous medium, whereby the resulting pressure increase from heating and pressure reduction from cooling in the first space and the third space respectively, causes the first piston and the second piston to reciprocate between an expansion movement during heating wherein the first and third variable spaces increases, and a compression movement during cooling wherein the first and third variable spaces decreases, whereby the first and second energy transfer devices transfer kinetic energy from the reciprocating movement of the reciprocatable pistons to an energy generating device arranged for being in an energy-transfer connection to the first and second reciprocatable pistons. Further, during the expansion movement of the first piston the fluid medium is forced out of the second space and into the fourth space aiding the compression movement of the second piston, and whereby during the expansion movement of the second piston the fluid medium is forced out of the fourth space and into the second space aiding the compression movement of the first piston.

[0006] According to one embodiment, the first and second energy transfer devices comprises a first and second fluid line respectively, respectively connecting the second variable space and fourth variable space with a further piston system, whereby the fluid lines, transfers the kinetic energy of the reciprocatable pistons via the further piston system, to the energy generating device.

[0007] According to one embodiment, the second and fourth variable spaces of the main piston system, via the fluid lines are in fluid connection with a first cylinder of the further piston system via a valve device, and wherein the second and fourth variable spaces of the main piston system, via the fluid lines are in fluid connection with a second cylinder of the further piston system via a valve device, wherein the valve devices are controlled by a valve control unit.

[0008] According to one embodiment, the first cylinder of the further piston system comprises a reciprocatable piston, sealably dividing the cylinder into a first and second variable space, wherein the first space comprises a fluid medium, and the second space comprises a fluid medium, wherein the second cylinder of the further piston system comprises a reciprocatable piston, sealably dividing the second cylinder into a third and fourth variable space, wherein the third space comprises a fluid medium, and the fourth space comprises a fluid medium, wherein the second space is in fluid connection with the fourth space, wherein the second and fourth variable spaces of the main piston system, via the fluid lines, are in fluid connection with the first and third variable spaces of the further piston system.

[0009] According to one embodiment, the second and fourth spaces of the main piston system are in fluid connection with a plurality of further pistons systems, comprising at least a first and second further piston system, in a similar arrangement as described in claims 2-4.

[0010] According to one embodiment, a movement cycle of the reciprocation of the pistons of the further piston system is time shifted in relation to the cycle time of at least one of the plurality of further piston systems.

[0011] According to one embodiment, the energy generating system further comprising a second main piston system similar to the first piston system according to any of the preceding claims 1-14, wherein the second main piston system is arranged to the further piston system according to claims 2-4, whereby the first and second energy transfer devices of the second main piston system transfer the kinetic energy from the reciprocating movement of the reciprocatable pistons to the energy generating device arranged for being in an energy-transfer connection to the first and second reciprocatable pistons, wherein a movement cycle of the reciprocation of the pistons of the second main piston system is time shifted in relation to the movement cycle of the pistons of the first main piston system.

[0012] According to one embodiment, the energy generating system further comprising a second main piston system similar to the first main piston system according to any of the embodiments described herein, wherein the second main piston system is arranged to the second further piston system, according to any of the embodiments described herein, wherein a movement cycle of the reciprocation of the pistons of the second main piston system is time shifted in relation to the movement cycle of the pistons of the first main piston system.

[0013] According to one embodiment, a preload cylinder, similar to the first cylinder of the further piston system as described in any of the embodiments herein, is arranged in fluid connection with the second space and the fourth variable space of the first cylinder of the further piston system for generating a preload to the fluid of the second space and the fourth variable space.

[0014] According to one embodiment, the first energy transfer device is connected to the first reciprocatable piston, and the second energy transfer device is connected to the second reciprocatable piston, wherein the second space is in fluid connection with the fourth space, whereby during expansion movement of the first piston the fluid medium is forced out of the second space into the fourth space aiding a compression movement of the second piston so that the third space is decreased, and whereby during expansion movement of the second piston the fluid medium is forced out of the fourth space into the second space aiding a compression movement of the first piston so that the first space is decreased.

[0015] According to one embodiment, the first heat exchanging system comprises a first heat exchanger, comprising a first valve to which a line for a hot medium and a line for cold medium is connected for selectively receiving a hot medium and a cold medium into the first heat exchanger, wherein the second heat exchanging system comprises a second heat exchanger comprising a second valve to which a line for a hot medium and a line for a cold medium is connected for selectively receiving a hot medium and a cold medium into the second heat exchanger, wherein the first and second valves are controlled by a valve control unit.

[0016] According to one embodiment, the first heat exchanger is in fluid connection with the cylinder via a third valve, and the second heat exchanger is in fluid connection with the cylinder via a fourth valve, wherein the opening and closing of valves are controllable by the valve control unit.

[0017] According to one embodiment, the first heat exchanging system and the second heat exchanging system comprises two separate heat exchangers respectively, wherein a first heat exchanger of the first system is adapted to heat the first gaseous medium, and a first heat exchanger of the second system is adapted to heat the second gaseous medium, and a second heat exchanger of the first system is adapted to cool the first medium, and a second heat exchanger of the second system is adapted to cool the third gaseous medium.

[0018] According to one embodiment, the first heat exchanging system is arranged within the first variable space of the cylinder, and/or the second heat exchanging system is arranged within the third variable space of the cylinder.

[0019] According to one embodiment, the first heat exchanging system is arranged externally of the cylinder, and/or the second heat exchanging system is arranged externally of the cylinder.

[0020] According to one embodiment, the fluid medium of the second space and the fluid medium of the fourth space is an incompressible liquid.

[0021] According to one embodiment, the fluid medium of the first space and the fluid medium of the third space is an incompressible liquid.

[0022] According to one embodiment, the fluid medium of the second space and the fluid medium of the fourth space is an incompressible liquid.

[0023] According to one embodiment, the liquid is oil.

[0024] According to one embodiment, the gaseous medium, is propane or R410A.

[0025] According to one embodiment, the gaseous medium, undergoes a phase transfer into a liquid phase during the compression movement and back into a gaseous phase during the expansion movement.

[0026] According to one embodiment, the fluid medium is a gaseous medium, e.g. nitrogen.

[0027] According to one embodiment, the fluid medium comprises a gaseous medium.

[0028] According to one embodiment, the hot medium is hot water and the cold medium is cold water.

[0029] According to one embodiment, the energy transfer devices comprises one of a mechanical transfer device such as a crank-link mechanism, magnets or coils.

[0030] According to one embodiment, the energy generating device comprises one of a rotating shaft in a crank-link mechanism, magnets, coils, and a generator.

Brief description of drawings

[0031] In the following, a detailed description of the invention will be given. In the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures. It will be appreciated that these figures are for illustration only and are not in any way restricting the scope of the invention.

[0032] Fig. 1 shows a side view of an energy generating system according to the invention.

[0033] Fig. 2 shows a side view of an energy generating system.

[0034] Fig. 3 shows a side view of an energy generating system.

[0035] Fig. 4 shows a side view of an energy generating system.

[0036] Fig. 5 shows a side view of an energy generating system.

[0037] Fig. 6 shows a side view of an energy generating system.

[0038] Fig. 7 shows a side view of an energy generating system.

Description of embodiments

[0039] In the following, a detailed description of the invention will be given. In the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures. It will be appreciated that these figures are for illustration only and are not in any way restricting the scope of the invention.

[0040] Fig. 1a shows a side view of an energy generating system 1 for generating energy from temperature differences of fluids. According to one embodiment, the energy generating system 1 comprises a first cylinder 14 comprising a first reciprocatable piston 15, wherein the first piston 15 sealably divides the first cylinder 14 into a first 14a and second 14b variable space, wherein the first space 14a comprises a first gaseous medium 140 and the second space 14b comprises a fluid medium 145. Further, the energy generating system 1 comprises a first energy transfer device 30a connected to the first cylinder 14.

[0041] The energy generating system 1 further comprises a first heat exchanging system 11 in fluid connection with the first space 14a, wherein the first heat exchanging system 11 is adapted to alternately heat and cool the first gaseous medium 140, whereby pressure in the first space 14a is increased and reduced respectively, a second cylinder 24 comprising a reciprocatable piston 25, wherein the second piston 25 sealably divides the second cylinder 24 into a third 24a and fourth 24b variable space, wherein the third space 24a comprises a second gaseous medium 240 and the fourth space 24b comprises a fluid medium 245. The energy generating system 1 further comprises a second energy transfer device 30b connected to the second cylinder 24, and a second heat exchanging system 21 in fluid connection with the third space 24a, wherein the second heat exchanging system 21 is adapted to alternately heat and cool the second gaseous medium 240, whereby pressure in the third space 24a is increased and reduced respectively, wherein the energy generating system 1 is adapted to control heating of the first gaseous medium 140 substantially simultaneously with cooling of the second gaseous medium 240 and conversely cooling of the first gaseous medium 140 substantially simultaneously with heating of the second gaseous medium 240, whereby the resulting pressure increase from heating and pressure reduction from cooling in the first space 14a and the third space 24a respectively, causes the first piston 15 and the second piston 25 to reciprocate between an expansion movement during heating wherein the first and third variable spaces 14a, 24a increases, and a compression movement during cooling wherein the first and third variable spaces 14a, 24a decreases, whereby the first and second energy transfer devices 30a, 30b transfer the kinetic energy from the reciprocating movement of the reciprocatable pistons 15, 25 to an energy generating device 30 arranged for being in an energy-transfer connection to the first and second reciprocatable pistons 15, 25.

[0042] According to one embodiment, the energy generating system 1 is adapted to synchronize heating of the first gaseous medium 140 with cooling of the second gaseous medium 240 and conversely cooling of the first gaseous medium 140 with heating of the second gaseous medium 240, whereby the resulting pressure increase from heating and pressure reduction from cooling in the first space 14a and the third space 24a respectively, causes the first piston 15 and the second piston 25 to reciprocate between an expansion movement during heating wherein the first and third variable spaces 14a, 24a increases, and a compression movement during cooling wherein the first and third variable spaces 14a, 24a decreases, whereby the first and second energy transfer devices 30a, 30b transfer the kinetic energy from the reciprocating movement of the reciprocatable pistons 15, 25 to an energy generating device 30 arranged for being in an energy-transfer connection to the first and second reciprocatable pistons 15, 25.

[0043] According to one embodiment, the stroke length of the reciprocatable pistons 15, 25 are 50-70cm.

[0044] According to one embodiment, the gaseous medium 140, 240 is propane or R410A. According to one embodiment, the selection of the gaseous medium is dependent on the temperature range of the mediums of the heat exchanging systems, 11, 21. According to one embodiment, the gaseous medium 140, 240 undergoes a phase transfer into a liquid phase during the compression movement and back into a gaseous phase during the expansion movement.

[0045] According to one embodiment, the pressure of the gaseous medium during heating, i.e. as a result of the pressure increase, is 15-16 Bar or 1,5-1,6 MPa when using propane. According to one embodiment, the pressure of the gaseous medium during heating, i.e. as a result of the pressure increase, is 30-40 Bar or 3-4 MPa when using propane. According to one embodiment, the pressure of the gaseous medium during cooling, i.e. as a result of the pressure reduction, is 2-4 Bar or 0,2-0, 4 MPa when using propane. According to one embodiment, the pressure of the gaseous medium during cooling, i.e. as a result of the pressure reduction, is 2-4 Bar or 0,2-0, 4 MPa when using propane.

[0046] According to one embodiment, the fluid medium 145 of the second space 14b and the fluid medium 245 of the fourth space 24b is an incompressible liquid. According to one embodiment, the liquid is oil. According to one embodiment, the fluid medium 145, 245 comprises a gaseous medium.

[0047] According to one embodiment, the energy transfer devices 30a, 30b, 30c, 30d comprises one of a mechanical transfer device such as a crank-link mechanism, magnets or coils. According to one embodiment, the energy generating device 30 comprises one of a rotating shaft in a crank-link mechanism, magnets, coils, and a generator, for generating energy from the movement of the reciprocatable pistons 15, 25,35, 45.

[0048] According to one embodiment, the first energy transfer device 30a is connected to the first reciprocatable piston 15, and the second energy transfer device 30b is connected to the second reciprocatable piston 25, wherein the second space 14b is in fluid connection with the fourth space 24b, whereby during expansion movement of the first piston 15 the fluid medium is forced out of the second space 14b into the fourth space aiding a compression movement of the second piston 25 so that the third space is decreased, and whereby during expansion movement of the second piston 25 the fluid medium is forced out of the fourth space 14b into the second space 14b aiding a compression movement of the first piston 25 so that the first space is decreased.

[0049] According to one embodiment, the first heat exchanging system 11 comprises a first heat exchanger 11a, comprising a first valve 12 to which a line 12a for a hot medium and a line 12b for cold medium is connected for selectively receiving a hot medium, such as e.g. a fluid, and a cold medium, such as e.g. a fluid, into the first heat exchanger 11, wherein the second heat exchanging system 21 comprises a second heat exchanger 21a comprising a second valve 22 to which a line 22a for a hot medium and a line 22b for a cold medium is connected for selectively receiving a hot medium and a cold medium into the second heat exchanger 21. According to one embodiment, the first and second valves 12, 22 are controlled by a valve control unit 50. According to one embodiment, the hot medium is hot water and the cold medium is cold water. According to one embodiment, the cold medium has a temperature of 4°-10°. According to one embodiment, the hot medium has a temperature of 15°-40°. According to one embodiment, the temperature difference between the hot medium and cold medium, ??, is in the range of 20°C-5°C difference. According to one embodiment, the warm side if the temperature difference exist below zero degrees Celsius. According to one embodiment, the cold water is ground water. According to one embodiment, the hot water is waste water or water heated by being exposed to solar energy or more specifically by means of solar collectors.

[0050] According to one embodiment, as seen in Fig. 1, the first heat exchanger 11 is in fluid connection with the cylinder 14 via a third valve 13, and the second heat exchanger 21 is in fluid connection with the cylinder 24 via a fourth valve 23, wherein the opening and closing of valves 13, 23 are controllable by the valve control unit 50.

[0051] Fig. 2 discloses the energy generating system 1 of Fig. 1, wherein the third valve 13 and the fourth valve 23 have been removed and the first heat exchanger 11 is in direct fluid connection with the cylinder 14, and the second heat exchanger 21 is in direct fluid connection with the cylinder 24.

[0052] Fig. 1 and Fig. 2 discloses the energy generating system 1 wherein the first heat exchanging system 11 is arranged externally of the cylinder 14, and/or the second heat exchanging system 21 is arranged externally of the cylinder 24.

[0053] According to one embodiment, the first heat exchanging system 11 and the second heat exchanging system 21 comprises two separate heat exchangers respectively (not shown), wherein a first heat exchanger of the first system 11 is adapted to heat the first 140 gaseous medium, and a first heat exchanger of the second system 21 is adapted to heat the second 240 gaseous medium, and a second heat exchanger of the first system 11 is adapted to cool the first medium 140, and a second heat exchanger of the second system 21 is adapted to cool the second 240 gaseous medium.

[0054] Fig. 3 discloses the energy generating system of Fig. 1, wherein the first heat exchanging system 11 is arranged within the first variable space 14a of the cylinder 14, and/or the second heat exchanging system 21 is arranged within the third variable space 24b of the cylinder 24.

[0055] Fig. 4 shows the energy generating system 1 according to one embodiment, wherein the first 30a and second 30b energy transfer devices comprises a first 30a, 30a1, 30a2 and second 30b, 30b1, 30b2 fluid line respectively, respectively connecting the second variable space 14b and fourth variable space 24b with a further piston system 2, whereby the fluid lines 30a1, 30b1, 30a2, 30b2 transfers the kinetic energy of the reciprocatable pistons 15, 25 via the further piston system 2, to the energy generating device 30.

[0056] Thus, according to one embodiment, again as seen in Fig. 4, the energy generating system 1 comprises a further piston system 2. wherein the further piston system 2 comprises: a first cylinder 34 comprising a first reciprocatable piston 35, wherein the first piston 35 sealably divides the first cylinder 34 into a first 34a and second 34b variable space, wherein the first space 34a comprises a fluid medium 340 and the second space 34b comprises a fluid medium 345, a first energy transfer device 30c connected to the first cylinder 34, a second cylinder 44 comprising a reciprocatable piston 45, wherein the second piston 45 sealably divides the second cylinder 44 into a third 44a and fourth 44b variable space, wherein the third space 44a comprises a fluid medium 440 and the fourth space 44b comprises a fluid medium 445, a second energy transfer device 30d connected to the second cylinder 44, wherein the first 30a and second 30b energy transfer devices of the main piston system 1' comprises a first 30a, 30a1, 30a2 and second 30b, 30b1, 30b2 fluid line respectively, whereby the second variable space 14b of the main piston system T is connected to the first variable space 34a of the further piston system 2 via the first fluid line 30a, 30a1, and further connected to the third variable space 44a of the further piston system 2 via a the first fluid line 30a, 30a2, whereby the fourth variable space 24b of the main piston system 1' is connected to the first variable space 34a of the further piston system 2 via the second fluid line 30b, 30b1, and further connected to the third variable space 44a of the further piston system 2 via a second fluid line 30b, 30b2, whereby the fluid lines 30a1, 30b1, 30a2, 30b2 transfers the kinetic energy of the reciprocatable pistons 15, 25 via the further piston system 2, to the energy generating device 30.

[0057] According to one embodiment, the second and fourth variable spaces 14b, 24b of the main piston system 1' , via the fluid lines 30a1, 30b1 are in fluid connection with a first cylinder 34 of the further piston system 2 via a valve device 33 comprising a respective valve 33a1, 33b1 for the respective fluid line 30a1 and 30b1, and wherein the second and fourth variable spaces 14b, 24 of the main piston system 1’, via the fluid lines 30a2, 30b2 are in fluid connection with a second cylinder 44 of the further piston system 2 via a valve device 43 comprising a respective valve 43a1, 43b1 for the respective fluid line 30a2, and 30b2.

According to one embodiment, the valve devices 33 and 43 are controlled by a valve control unit 50.

[0058] According to one embodiment, the fluid medium 340 of the first space 34a and the fluid medium 440 of the second space 44a is an incompressible liquid. According to one embodiment, the liquid is oil. According to one embodiment, the fluid medium 340 of the first space 34a and the fluid medium 440 of the second space 44a is the same fluid medium 145 of the second space 14b and the fluid medium 245 of the fourth space 24b.

[0059] According to one embodiment, the fluid medium 345 of the second space 34b and the fluid medium 445 of the fourth space 44b is an incompressible liquid. According to one embodiment, the liquid is oil. According to one embodiment, the fluid mediums 345, 445 is a gaseous medium, wherein the gaseous medium is nitrogen.

[0060] According to one embodiment, the first cylinder 34 of the further piston system 2 comprises a reciprocatable piston 35, sealably dividing the cylinder 34 into a first 34a and second 34b variable space, wherein the first space 34a comprises a fluid medium 340, and the second space 34b comprises a gaseous medium 345, wherein the second cylinder 44 of the further piston system 2 comprises a reciprocatable piston 45, sealably dividing the second cylinder 44 into a third 44a and fourth 44b variable space, wherein the third space 44a comprises a fluid medium 440, and the fourth space 44b comprises a gaseous medium 445, wherein the second space 34b is in fluid connection with the fourth space 44b, wherein the second 14b and fourth 24b variable spaces of the main piston system 1 via the fluid lines 30a1, 30a2, 30b1, 30b2, are in fluid connection with the first 34a and third 44a variable spaces of the further piston system 2.

[0061] According to one embodiment, the second and fourth spaces 14b, 24b of the main piston system 1’ are in fluid connection with a plurality of further pistons systems 2, 2’, comprising at least a first and second further piston system 2, 2’ in a similar arrangement as described above (not shown).

[0062] According to one embodiment, a movement cycle of the reciprocation of the pistons of the further piston system 2 is time shifted in relation to the cycle time of at least one of the plurality of further piston systems 2’. According to one embodiment, the time shifted movement cycle between further pistons systems 2, 2’ is achieved by means of controlling of the valve devices 33, 43 by the control unit 50.

[0063] According to one embodiment, an energy generating system 1 is provided, wherein the energy generating system 1 comprises a second main piston system 1” similar to the first piston system 1’ as described above, wherein the second main piston system 1” is arranged to the further piston system 2, in a similar manner as the first main piston system 1' is arranged to the first further piston system 2 as described above, whereby the first and second energy transfer devices 30a”, 30b” of the second main piston system 1” transfer the kinetic energy from the reciprocating movement of the reciprocatable pistons 15”, 25” to the energy generating device 30 arranged for being in an energy-transfer connection to the first and second reciprocatable pistons 15”, 25”.

[0064] According to one embodiment, a movement cycle of the reciprocation of the pistons of the second main piston system 1” is time shifted in relation to the movement cycle of the pistons of the first main piston system 1’.

[0065] Fig. 5 discloses the energy generating system 1, according to one embodiment, wherein the energy generating system 1 comprises a second main piston system 1” similar to the first main piston system 1’ as described above, wherein the second main piston system 1” is arranged to the second further piston systems 2’, in a similar manner as the first main piston system 1’ is arranged to the first further piston system 2 as described above, wherein a movement cycle of the reciprocation of the pistons of the second main piston system 1” is time shifted in relation to the movement cycle of the pistons of the first main piston system 1’.

[0066] According to one embodiment as described in Fig. 5, the first 30a and second 30b energy transfer devices of the main piston system 1' further comprises a first 30a, 30a1, 30a2, 30a3, 30a4 and second 30b, 30b1, 30b2, 30b3, 30b4 fluid line respectively, whereby the second variable space 14b of the main piston system 1' is further connected to the first variable space 54a of the second further piston system 2 via the first fluid line 30a, 30a3, (not shown) and further connected to the third variable space 64a of the second further piston system 2’ via a the first fluid line 30a, 30a4, whereby the fourth variable space 24b of the main piston system 1' is connected to the first variable space 54a of the first further piston system 2 via the second fluid line 30b, 30b3, and further connected to the third variable space 64a of the second further piston system 2’ via a second fluid line 30b, 30b4, whereby the fluid lines 30a3, 30b3, 30a4, 30b4 transfers the kinetic energy of the reciprocatable pistons 15, 25 via the second further piston system 2’, to the energy generating device 30. According to one embodiment, the valve devices 33 and 43 of the second main piston system 1” comprises additional valves 33a2, 33b2 and 43a2, 43b2 respectively for connecting the respective fluid lines 30a3, 30b3 and 30a4, 30b4 to the first variable space 54a and third variable space 64a. Additionally, an analogous set up can be provided between the second main piston system 1” and the first further pistons system 2 as described.

[0067] Fig. 6 discloses the energy generating system 1, according to one embodiment, wherein a preload cylinder 74, similar to the first cylinder 34 of the further piston system 2 as described above, is arranged in fluid connection with the second space 34b and the fourth variable space 44b of the first cylinder 34 and second cylinder 44 of the further piston system 2 for generating a preload to the fluid of the second space 34b and the fourth variable space 44b. According to one embodiment, the preload cylinder 74, is arranged in fluid connection with the second space 54b and the fourth variable space 64b of the first cylinder 54 and the second cylinder 64 of the second further piston system 2’ for generating a preload to the fluid of the second space 34b and the fourth variable space 44b. According to one embodiment, a valve device (not shown) is arranged in the lines connecting the first and second cylinder 34, 44 and first and second cylinder 54, 64 respectively. According to one embodiment, the preload is a slight overpressure compared to the pressure in the first and second variable spaces 14a, 24a. According to one embodiment, the overpressure is in the range of 1-2 Bar.

[0068] Fig. 7 discloses the energy generating system 1, according to one embodiment of the invention. The main pistons 5, 6, 7, 8 compressing gaseous medium causing a phase transfer of the gas by cooling or expanding gas by heating, which alternately is provided to heat exchanging systems arranged in fluid connection with each main piston 5, 6, 7, 8. The gaseous medium is housed in the lower part of the main pistons as well as in each heat exchanging system. Cooling and heating in liquid form is provided and returned from the heat exchanging systems via two 3-way valves arranged to each heat exchanging system. The upper part of each main piston and the fluid lines connected to the lower parts of the piston pairs 1, 2, 3, 4 is filled with e.g. hydraulic oil. The main pistons work in pairs, wherein main piston 5 is heated and has a relatively higher pressure than main piston 7 having a low pressure, connected to fluid line 56 and 78 respectively. Piston pairs 1-4 is connected in sequence via valves to fluid lines 56 and 78 so that at least one piston pair drives and rotates the drive shaft, or, transfers energy to the energy generating device by any other means. In Fig. 7, a fluid line is connected to the fluid line 56 and presses one piston in the piston pair to an upper end position, while the other piston of the piston pair is pressed back to a lower end position and hydraulic oil back via fluid line 78 to main piston 7. Pressurization line connected to the upper part in the piston pairs has a slight overpressure compared to the lowest pressure obtainable by heat exchanging by cooling in the main pistons. This overpressure allows in this case the transfer of gas into liquid phase in the heat exchanging system and the lower part of main piston 7 where the pressure as a result decreases rapidly. Eventually, the main pistons 5 and 7 have reached their end positions. At this point, the valves V56 and V78 switch over to main piston 6 and 8 and the process starts over. While main piston 6 and 8 work toward their end positions, main piston 5 and 7 are undergoing a heat exchange wherein the piston previously heated is now cooled (5) and the piston previously cooled is now heated (7) so that they are ready to start when main piston 6 and 8 are ready.

[0069] A preferred embodiment of an energy generating system 1 according to the invention has been described. However, the person skilled in the art realizes that this can be varied within the scope of the appended claims without departing from the inventive idea.

[0070] All the described alternative embodiments above or parts of an embodiment can be freely combined without departing from the inventive idea as long as the combination is not contradictory.

Claims

1. An energy generating system (1) comprising: a main piston system (V), further comprising, a first cylinder (14) comprising a first reciprocatable piston (15), wherein the first piston (15) sealably divides the first cylinder (14) into a first (14a) and second (14b) variable space, wherein the first space (14a) comprises a first gaseous medium (140) and the second space (14b) comprises a fluid medium (145), a first energy transfer device 30a connected to the first cylinder (14), a first heat exchanging system (11) in fluid connection with the first space (14a), wherein the first heat exchanging system (11) is adapted to alternately heat and cool the first gaseous medium (140), whereby pressure in the first space (14a) is increased and reduced respectively, a second cylinder (24) comprising a reciprocatable piston (25), wherein the second piston (25) sealably divides the second cylinder (24) into a third (24a) and fourth (24b) variable space, wherein the third space (24a) comprises a second gaseous medium (240) and the fourth space 24b comprises a fluid medium (245), a second energy transfer device 30b connected to the second cylinder (24), a second heat exchanging system (21) in fluid connection with the third space (24a), wherein the second heat exchanging system (21) is adapted to alternately heat and cool the second gaseous medium (240), whereby pressure in the third space (24a) is increased and reduced respectively, wherein the energy generating system (1) is adapted to control heating of the first gaseous medium (140) substantially simultaneously with cooling of the second gaseous medium (240) and conversely cooling of the first gaseous medium (140) substantially simultaneously with heating of the second gaseous medium (240), whereby the resulting pressure increase from heating and pressure reduction from cooling in the first space (14a) and the third space (24a) respectively, causes the first piston (15) and the second piston (25) to reciprocate between an expansion movement during heating wherein the first and third variable spaces (14a, 24a) increases, and a compression movement during cooling wherein the first and third variable spaces (14a, 24a) decreases, whereby the first and second energy transfer devices (30a, 30b) transfer kinetic energy from the reciprocating movement of the reciprocatable pistons (15, 25) to an energy generating device (30) arranged for being in an energy-transfer connection to the first and second reciprocatable pistons (15, 25), whereby during the expansion movement of the first piston (15) the fluid medium (145, 245) is forced out of the second space (14b) and into the fourth space (24b) aiding the compression movement of the second piston (25), and whereby during the expansion movement of the second piston (25) the fluid medium (145, 245) is forced out of the fourth space (24b) and into the second space (14b) aiding the compression movement of the first piston (25).

2. An energy generating system (1) according to claim 1, whereby the first (30a) and second (30b) energy transfer devices comprises a first (30a1, 30b1) and second (30a2, 30b2) fluid line respectively, respectively connecting the second variable space (14b) and fourth variable space (24b) with a further piston system (2), whereby the fluid lines (30a1, 30b1, 30a2, 30b2) transfers the kinetic energy of the reciprocatable pistons (15, 25) via the further piston system (2), to the energy generating device (30).

3. The energy generating system (1) according to claim 2, wherein the second and fourth variable spaces (14b, 24b) of the main piston system (1’), via the fluid lines (30a1, 30b1) are in fluid connection with a first cylinder (34) of the further piston system (2) via a valve device (33), and wherein the second and fourth variable spaces (14b, 24) of the main piston system (1’), via the fluid lines (30a2, 30b2) are in fluid connection with a second cylinder (44) of the further piston system (2) via a valve device (43), wherein the valve devices (33) and (43) are controlled by a valve control unit (50).

4. The energy generating system (1) according to claim 3, wherein the first cylinder (34) of the further piston system (2) comprises a reciprocatable piston (35), sealably dividing the cylinder (34) into a first (34a) and second (34b) variable space, wherein the first space (34a) comprises a fluid medium (340), and the second space (34b) comprises a fluid medium (345), wherein the second cylinder (44) of the further piston system (2) comprises a reciprocatable piston (45), sealably dividing the second cylinder (44) into a third (44a) and fourth (44b) variable space, wherein the third space (44a) comprises a fluid medium (440), and the fourth space (44b) comprises a fluid medium (445), wherein the second space (34b) is in fluid connection with the fourth space (44b), wherein the second (14b) and fourth (24b) variable spaces of the main piston system (1’), via the fluid lines (30a1, 30a2, 30b1, 30b2), are in fluid connection with the first (34a) and third (44a) variable spaces of the further piston system (2).

5. The energy generating system (1) according to any of the preceding claims 2-4, wherein the second and fourth spaces (14b, 24b) of the main piston system (T) are in fluid connection with a plurality of further pistons systems (2, 2’), comprising at least a first and second further piston system (2, 2’).

6. The energy generating system (1) according to claim 5, wherein a movement cycle of the reciprocation of the pistons of the further piston system (2) is time shifted in relation to the cycle time of at least one of the plurality of further piston systems (2’).

7. The energy generating system (1) according to any of claims 2-4, comprising a second main piston system (1”), wherein the second main piston system (1") is arranged to the further piston system (2), whereby the first and second energy transfer devices (30a”, 30b”) of the second main piston system (1") transfer the kinetic energy from the reciprocating movement of the reciprocatable pistons (15”, 25”) to the energy generating device (30) arranged for being in an energy-transfer connection to the first and second reciprocatable pistons (15”, 25”), wherein a movement cycle of the reciprocation of the pistons of the second main piston system (1”) is time shifted in relation to the movement cycle of the pistons of the first main piston system (1').

8. The energy generating system (1) according to any of the preceding claims 5-7, comprising a second main piston system (1”), wherein the second main piston system (1") is arranged to the second further piston system (2’), wherein a movement cycle of the reciprocation of the pistons of the second main piston system (1”) is time shifted in relation to the movement cycle of the pistons of the first main piston system (1').

9. The energy generating system (1) according to any of the preceding claims 3-8, wherein a preload cylinder (74) is arranged in fluid connection with the second space (34b) and the fourth variable space (44b) of the first cylinder (34) of the further piston system (2) for generating a preload to the fluid of the second space (34b) and the fourth variable space (44b).

10. The energy generating system (1) according to claim 1, wherein the first energy transfer device (30a) is connected to the first reciprocatable piston (15), and the second energy transfer device (30b) is connected to the second reciprocatable piston (25), wherein the second space (14b) is in fluid connection with the fourth space (24b), whereby during expansion movement of the first piston (15) the fluid medium is forced out of the second space (14b) into the fourth space aiding a compression movement of the second piston (25) so that the third space is decreased, and whereby during expansion movement of the second piston (25) the fluid medium is forced out of the fourth space (14b) into the second space (14b) aiding a compression movement of the first piston (25) so that the first space is decreased.

11. . The energy generating system (1) according to any of the preceding claims 1-10, wherein the first heat exchanging system (11) comprises a first heat exchanger (11a), comprising a first valve (12) to which a line (12a) for a hot medium and a line (12b) for cold medium is connected for selectively receiving a hot medium and a cold medium into the first heat exchanger (11), wherein the second heat exchanging system (21) comprises a second heat exchanger (21a) comprising a second valve (22) to which a line (22a) for a hot medium and a line (22b) for a cold medium is connected for selectively receiving a hot medium and a cold medium into the second heat exchanger (21), wherein the first and second valves (12, 22) are controlled by a valve control unit (50).

12. The energy generating system (1) according to any of the preceding claims 1-11, wherein the first heat exchanger (11) is in fluid connection with the cylinder (14) via a third valve (13), and the second heat exchanger (21) is in fluid connection with the cylinder (24) via a fourth valve (23), wherein the opening and closing of valves (13, 23) are controllable by the valve control unit (50)

13. The energy generating system (1) according to any of the preceding claims 1-12, wherein the first heat exchanging system (11) and the second heat exchanging system (21) comprises two separate heat exchangers respectively, wherein a first heat exchanger of the first system (11) is adapted to heat the first (140) gaseous medium, and a first heat exchanger of the second system (21) is adapted to heat the second (240) gaseous medium, and a second heat exchanger of the first system (11) is adapted to cool the first medium (140), and a second heat exchanger of the second system (21) is adapted to cool the third (240) gaseous medium.

14. The energy generating system (1) according to any of the preceding claims 1-13, wherein the first heat exchanging system (11) is arranged within the first variable space (14a) of the cylinder (14), and/or the second heat exchanging system (21) is arranged within the third variable space (24b) of the cylinder (24).

15. The energy generating system (1) according to any of the preceding claims 1-14, wherein the first heat exchanging system (11) is arranged externally of the cylinder (14), and/or the second heat exchanging system (21) is arranged externally of the cylinder (24).

16. The energy generating system (1) according to any of the preceding claims 1-15, wherein the fluid medium (145) of the second space (14b) and the fluid medium (245) of the fourth space (24b) is an incompressible liquid.

17. The energy generating system (1) according to any of the preceding claims 4-16, wherein the fluid medium (340) of the first space (34a) and the fluid medium (440) of the third space (44a) is an incompressible liquid.

18. The energy generating system (1) according to any of the preceding claims 4-17, wherein the fluid medium (345) of the second space (34b) and the fluid medium (445) of the fourth space (44b) is an incompressible liquid.

19. The energy generating system (1) according to any of the preceding claims 16-18, wherein the liquid (340, 440, 345, 445) is oil (340, 440, 345, 445).

20. The energy generating system (1) according to any of the preceding claims 1-19, wherein the gaseous medium (140, 240) is propane or R410A.

21. The energy generating system (1) according to any of the previous claims, wherein the gaseous medium (140, 240) undergoes a phase transfer into a liquid phase during the compression movement and back into a gaseous phase during the expansion movement.

22. The energy generating system (1) according to any of the preceding claims 4-17, 20-21, wherein the fluid medium (345, 445) is a gaseous medium, e.g. nitrogen.

23. The energy generating system (1) according to any of the preceding claims 1-15, 20-22, wherein the fluid medium (145, 245) comprises a gaseous medium.

24. The energy generating system (1) according to claim 11, wherein the hot medium is hot water and the cold medium is cold water.

25. The energy generating system (1) according to any of the preceding claims 1-24, wherein the energy transfer devices (30a, 30b, 30c, 30d) comprises one of a mechanical transfer device such as a crank-link mechanism, magnets or coils.

26. The energy generating system (1) according to any of the preceding claims 1-25, wherein the energy generating device (30) comprises one of a rotating shaft in a crank-link mechanism, magnets, coils, and a generator.