WO2024055113A1 - A heat exchange process and an energy storage system - Google Patents

Abstract

A heat exchange process includes the steps of: providing a heating fluid to a heat exchange device; providing a cooling fluid to the heat exchange device; cooling the heating fluid in the heat exchange device to produce cooled fluid; heating the cooling fluid in the heat exchange device to produce heated fluid, the heated fluid having a temperature; exhausting the cooled fluid into the atmosphere; transferring the heated fluid into a cooling medium wherein the cooling medium is one of land and water, the cooling medium having a temperature; and wherein the temperature of the cooling medium may be at least 0.1˚C less than the temperature of heated fluid. An energy storage system includes a storage tank, a gas expander and a gas compressor. The energy storage system is configured such that during expansion a cooled fluid is produced that is exhausted into the atmosphere.

Description

A HEAT EXCHANGE PROCESS AND AN ENERGY STORAGE SYSTEM

BACKGROUND

[0001] The present disclosure relates to a heat exchange process and an energy storage system.

[0002] Traditionally, there have been two known types of living organisms defined by the primary form of life energy they consume - phototrophs (photosynthetic plants) and chemotrophs (such as animals and most microorganisms), which use the energy of light and chemical energy, respectively. In both groups of organisms, the various types of energy needed to sustain life (i.e. mechanical, thermal, electrical, chemical) are produced via conversion of the two primary forms of life energy, which takes place inside the living organisms (in vivo). The main exception are humans, who in addition to the in vivo energy conversions, make use of energy conversions outside of their bodies (ex vivo) by producing forms of energy not directly needed for life. Historically, the first and still the most important ex vivo energy conversions practiced by humans is the conversion of chemical energy to heat energy (fuel oxidation), or the command of fire. From the point of view of energy, it was proposed that humans became different from any other form of life when they started using ex-vivo energy conversions such as fire. In the last several thousands of years, people began exploring the ex-vivo use of alternative fuels. The ex-vivo fossil fuel energy conversions by humans led ultimately to the possibility of affecting the environment of the entire planet.

[0003] The process of chemical fuel oxidation involves two significant types of emissions to the environment: mass (primarily carbon dioxide and water vapor) and energy (mostly as sensible heat, plus some electromagnetic energy in the visible and infrared spectrum). The difference between sensible and radiant heat is that sensible heat is based on the vibration energy of atoms and molecules while infrared heat has an electromagnetic wave nature.

[0004] With the continuing industrialization of society, dramatic increases in both carbon dioxide and heat emissions have been taking place on a global scale. Since the beginning of the 20th century, the CO2 concentration in the atmosphere has reached such high levels that it has been purported to be the primary cause of the dramatic increase of atmospheric temperature observed, commonly referred to as “global warming”. The latter is responsible for drastic, mostly negative, changes in climate. Therefore, it is of great importance to slow down the increase, and even to decrease, the atmospheric temperature globally.

[0005] So far, global warming has been blamed exclusively on greenhouse gas (such as carbon dioxide) emissions and the resulting greenhouse gas effect. The atmospheric temperature rise can be reduced by four major methods: (1) by the reduction of carbon dioxide emissions; (2) by carbon dioxide removal from the atmosphere; (3) by reducing the sensible heat emissions to the atmosphere; (4) by geoengineering methods and (5) by removing sensible heat from the atmosphere (direct cooling the atmosphere). Method #5 is the subject of this disclosure herein.

[0006] Currently, the main worldwide solution to decrease, or in the future to eliminate, global warming is based on the decrease of anthropogenic carbon dioxide emissions. One of the problems with that method is that the lifetime of CO2 in atmosphere is very long, of the order of centuries. Therefore, the result of the CO2 emissions decrease will only be felt after decades. Another problem is the lack of technological readiness to quickly reduce the anthropogenic CO2 emissions. Therefore, the decrease of CO2 emissions needs to be supplemented with technologies that will quickly reduce the atmospheric temperature. Different methods of climate engineering are being considered to achieve that goal. For example, solar geoengineering is based on the introduction of aerosols to the atmosphere, which would have a cooling effect. Among the main problems of climate engineering are the risk of unexpected negative effects on the entire biosphere and the difficulty in controlling the process.

SUMMARY

[0007] A further understanding of the functional and advantageous aspects of the disclosure can be realized by reference to the following detailed description and drawings.

[0008] A heat exchange process includes the steps of: providing a heating fluid to a heat exchange device, the heating fluid having a temperature; providing a cooling fluid to the heat exchange device; cooling the heating fluid in the heat exchange device to produce cooled fluid; heating the cooling fluid in the heat exchange device to produce heated fluid, the heated fluid having a temperature; exhausting the cooled fluid into the atmosphere; transferring the heated fluid into a cooling medium wherein the cooling medium is one of land and water, the cooling medium having a temperature; and wherein the temperature of the cooling medium is at least 0.1 °C less than the temperature of heated fluid.

[0009] The temperature of the cooling medium may be at least 0.2°C less than the temperature of the heating fluid. [0010] The heat exchange device may be a heat exchanger.

[0011] The heat exchanger may be located in the cooling medium. The cooling fluid may be provided from the cooling medium. The heating fluid may be pumped into the heat exchanger. An insulated conduit for exhausting the cooled air from the heat exchanger into the atmosphere.

[0012] The heating fluid may be air from the atmosphere.

[0013] The heating fluid may be a first heating fluid and the heat exchanger may be a first heat exchanger and the step of cooling the heating fluid in a heat exchanger to produce a cooled fluid may be the step of cooling a first heating fluid in the first heat exchanger to produce a first cooled fluid and further including the steps of providing a second heating fluid being air from the atmosphere and cooling the second heating fluid in a second heat exchanger to produce the cooled fluid.

[0014] The heat exchange device may include multiple devices including a gas compressor and a gas expander and wherein heat exchange is a bi-product of gas compression and gas expansion and further including the steps of: providing gas; compressing the gas in the gas compressor to produce compressed gas; wherein the cooling fluid may be provided to the gas compressor; transferring the compressed gas to an auxiliary unit; transferring the compressed gas from the auxiliary unit to the gas expander; wherein the heating fluid may be provided to the gas expander; and exhausting the expanded gas.

[0015] The auxiliary unit may be a compressed gas vessel. The compressed gas vessel may be used to store energy. The compressed gas vessel may bean elongate pipe. The elongate pipe may be used to transport and store energy. The elongate pipe has a length and the length may be up to at least a thousand kilometers.

[0016] The step of compressing the gas consumes power.

[0017] The step of expanding the compressed gas generates power.

[0018] The gas compressor and the gas expander may have one of a common shaft and a common crank wheel.

[0019] The step of expanding the compressed gas may be carried out at ambient temperature.

[0020] The step of compressing the gas may be carried out at the temperature of the cooling medium.

[0021] An energy storage system includes a storage tank, a gas expander, and a gas compressor.

[0022] The gas expander includes an expander’s hydraulic cylinder, an expander’s variable pressure vessel. The expander’s hydraulic cylinder has a variable working volume responsive to motion of a piston and, wherein the variable working volume of the expander’s hydraulic cylinder increases during an expander’s first stroke and the variable working volume of the expander’s hydraulic cylinder decreases during an expander’s second stroke. The expander’s variable pressure vessel has a volume and being operably connected to the expander’s hydraulic cylinder and operably connected to the storage tank. The expander’s variable pressure vessel includes an expander’s liquid chamber and an expander’s gas chamber. The expander’s liquid chamber has a variable volume that decreases responsive to the expander’s first stroke and increases responsive to the expander’s second stroke. The expander’s gas chamber has a variable volume that increases responsive to the expander’s first stroke and decreases responsive to the expander’s second stroke, the expander’s gas chamber has an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough. A heating fluid such that during expansion, heat from the heating fluid is transferred through the outer wall of the expander variable pressure vessel and a cooled fluid is produced that is exhausted into the atmosphere. A moveable barrier between the expander liquid chamber and the expander gas chamber such that movement of the moveable barrier causes the volume in the expander liquid chamber and the volume in the expander gas chamber to displace each other and the volume in the expander gas chamber plus the volume in the expander liquid chamber is generally constant and generally equals the volume in the expander variable pressure vessel.

[0023] The gas compressor includes a compressor’s hydraulic cylinder and a compressor’s variable pressure vessel. The compressor’s hydraulic cylinder has a variable working volume responsive to motion of a piston. The variable working volume of the compressor’s hydraulic cylinder increases during a compressor’s first stroke and the variable working volume of the compressor’s hydraulic cylinder decreases during a compressor’s second stroke. The compressor’s variable pressure vessel has a volume and being operably connected to the compressor’s hydraulic cylinder and operably connected to the storage tank. The compressor’s variable pressure vessel includes a compressor’s liquid chamber and a compressor’s gas chamber. The compressor’s liquid chamber has a variable volume that decreases responsive to the compressor’s first stroke and increases responsive to the compressor’s second stroke. The compressor’s gas chamber has a variable volume that increases responsive to the compressor’s first stroke and decreases responsive to the compressor’s second stroke. The compressor’s gas chamber has an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough. A cooling fluid such that during compression, heat is produced and the heat is used to heat the cooling fluid to produce heated fluid that is transferred to a cooling medium. The cooling medium is one of land and water. A moveable barrier between the compressor’s liquid chamber and the compressor’s gas chamber. Movement of the moveable barrier causes the volume in the compressor’s liquid chamber and the volume in the compressor’s gas chamber to displace each other. The volume in the compressor’s gas chamber plus the volume in the compressor’s liquid chamber is generally constant and generally equals the volume in the compressor’s variable pressure vessel.

[0024] The energy storage system may include an energy conversion device operably connected to the expander’s hydraulic cylinder and operably connected to the compressor’s hydraulic cylinder.

[0025] The energy conversion device may be an electric generator.

[0026] A first energy conversion device may be operably connected to the expander’s hydraulic cylinder and a second energy conversion device operably connected to the compressor’s hydraulic cylinder. The first energy conversion device may be an electric generator and the second energy storage device may be an electric motor.

[0027] The heating fluid may be ambient air.

[0028] The energy storage system may include fins operably connected to the thermally conductive portion of the outer wall of the expander’s variable pressure vessel. [0029] An expander’s cooling jacket may be operably connected to the thermally conductive portion of the outer wall of the expander’s variable pressure vessel and wherein the heating fluid may be in the expander’s cooling jacket.

[0030] A heat exchanger has an inlet and an outlet and the heat exchanger inlet may be in fluid communication with the cooling jacket and the heat exchanger outlet may be in fluid communication with the cooling jacket.

[0031] A compressor’s cooling jacket may be operably connected to the thermally conductive portion of the outer wall of the compressor’s variable pressure vessel and wherein the cooling fluid may be in the compressor’s cooling jacket. The compressor’s cooling jacket may have an inner surface and an outer surface. The inner surface may be in thermal communication with the outer wall of the compressor’s variable pressure vessel. A thermal insulation layer may be in thermal communication with the outer surface of the compressor’s cooling jacket. A conduit may be in fluid communication with the cooling jacket and a pump may be operably connected to the conduit. The cooling fluid may be provided to the conduit.

[0032] The cooling fluid may be water from one of an ocean, a sea, a lake, a river, and groundwater.

[0033] The expander and compressor may be a combination expander/compressor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Embodiments will now be described, by way of example only, with reference to the drawings, in which:

[0035] FIG. 1 is a schematic diagram of a heat exchanger;

[0036] FIG. 2 is a schematic diagram of a heat exchanger located in a cooling medium; [0037] FIG. 3 is a schematic diagram of a heat exchanger located in the atmosphere and fluid is pumped from the cooling medium to the heat exchanger;

[0038] FIG. 4 is a schematic diagram similar to the that shown in FIG. 3 but showing a closed loop system with a heat exchanger in the atmosphere fluid with fluid being pumped into a second heat exchanger which is located in the cooling medium and then to the heat exchanger;

[0039] FIG. 5 is a schematic diagram of a heat exchange process that uses a gas compressor and a gas expander and includes an auxiliary unit;

[0040] FIG. 6 is a schematic diagram of a heat exchange process similar to that shown in FIG. 5 but having a compressed air vessel used for energy storage;

[0041] FIG. 7 is a schematic diagram of a heat exchange process similar to that shown in FIG. 5 but having an elongate pipe used for energy transport;

[0042] FIG. 8 is a schematic diagram of a heat exchange process similar to that shown in FIG. 5, further including an electric motor/generator and having a common shaft or crank wheel;

[0043] FIG. 9 is a schematic diagram of a heat exchange process similar to that shown in FIG. 8 but including a compressed gas vessel.

[0044] FIG. 10 is a schematic diagram of a prior art showing a process of isothermal compression;

[0045] FIG. 11 is a schematic diagram of a prior art showing a process of isothermal expansion;

[0046] FIG. 12 is a schematic diagram of an energy storage system similar to that shown in FIGS. 10 and 11 but including a system for cooling the atmosphere;

[0047] FIG. 13 is a schematic diagram of an energy storage system similar to that shown in FIG. 12 but having a combined motor/generator; [0048] FIG. 14 is a schematic diagram of an energy storage system similar to that shown in FIG. 12 and showing heat exchange through the external wall of the expander;

[0049] FIG. 15 is a schematic diagram of an energy storage system similar to that shown in FIG. 12 and showing fins on the external wall of the expander to increase heat transfer;

[0050] FIG. 16 is a schematic diagram of an energy storage system similar to that shown in FIG. 12 and showing an external heat exchanger;

[0051] FIG. 17 is a schematic diagram of an energy storage system similar to that shown in FIG. 12 and showing an air-cooling jacket on the expander;

[0052] FIG. 18 is a schematic diagram of an energy storage system similar to that shown in FIG. 12 and showing a cooling jacket on the compressor;

[0053] FIG. 19 is a schematic diagram of an energy storage system similar to that shown in FIG. 18 and showing an external heat exchanger in the cooling medium;

[0054] FIG. 20 is a schematic diagram of an energy storage system similar to that shown in FIG. 12 and showing the compressor and the expander in a combined compressor/expander;

[0055] FIG. 21 is a schematic diagram of an energy storage system similar to that shown in FIG. 20 and showing an external heat exchanger;

[0056] FIG. 22 is a schematic diagram of an energy storage system similar to that shown in FIG. 21 and showing a double hydraulic cylinder and multiple compression/expansion vessels;

[0057] FIG. 23 is a schematic diagram of an energy storage system similar to that shown in FIG. 22 and showing a different phase in an energy storage cycle;

[0058] FIG. 24A is a schematic diagram of a compression/expansion vessel; [0059] FIG. 24B is a cross sectional view of the compression/expansion vessel of FIG. 24A;

[0060] FIG. 25 is a schematic diagram of an energy storage system similar to that shown in FIG. 12 and showing

[0061] FIG. 26 is a schematic diagram of an energy storage system similar to that shown in FIG. 20 and showing an expansion vessel and a compression vessel;

[0062] FIG. 27 is a schematic diagram of an energy storage system similar to that shown in FIG. 26 and showing the heat from the compression vessel exhausted to a cooling medium;

[0063] FIG. 28 is a schematic diagram of an energy storage system similar to that shown in FIG. 27 and showing a heat exchanger connected between the compression vessel and the expansion vessel;

[0064] FIG. 29 is a schematic diagram of an energy storage system similar to that shown in FIG. 28 but without the heat exchanger;

[0065] FIG. 30 is a schematic diagram of an energy storage system similar to that shown in FIG. 28 and showing heat transfer fluid for the heat sink connected to a cooling medium;

[0066] FIG. 31 is a schematic diagram of an energy storage system similar to that shown in FIG. 30 but without the heat exchanger; and

[0067] FIG. 32 is a graph showing the change in temperature during 90 minutes of compression.

DETAILED DESCRIPTION

[0068] Various embodiments and aspects of the disclosure will be described with reference to details discussed below. The following description and drawings are illustrative of the disclosure and are not to be construed as limiting the disclosure.

Numerous specific details are described to provide a thorough understanding of various embodiments of the present disclosure. However, in certain instances, well-known or conventional details are not described in order to provide a concise discussion of embodiments of the present disclosure.

[0069] As used herein, the terms “comprises” and “comprising” are to be construed as being inclusive and open ended, and not exclusive. Specifically, when used in the specification and claims, the terms “comprises” and “comprising” and variations thereof mean the specified features, steps or components are included. These terms are not to be interpreted to exclude the presence of other features, steps or components.

[0070] As used herein, the term “approximately” is meant to cover variations that may exist in the upper and lower limits of the ranges of values, such as variations in properties, parameters, and dimensions. Unless otherwise specified, the term “approximately” mean plus or minus 25 percent or less.

[0071] It is to be understood that unless otherwise specified, any specified range or group is as a shorthand way of referring to each and every member of a range or group individually, as well as each and every possible sub-range or sub-group encompassed therein and similarly with respect to any sub-ranges or sub-groups therein. Unless otherwise specified, the present disclosure relates to and explicitly incorporates each and every specific member and combination of sub-ranges or sub-groups.

[0072] As used herein the “operably connected” or “operably attached” means that the two elements are connected or attached either directly or indirectly. Accordingly, the items need not be directly connected or attached but may have other items connected or attached therebetween.

[0073] A system is disclosed here to mitigate global warming by the direct removal of sensible heat from the atmosphere and transferring it to outside of the atmosphere, in water and/or land. In that case the atmosphere acts as a heat source, and the water and/or land acts as a heat sink in a thermodynamic process. One of the main advantages of that method is that contrary to the CO2 emission reduction, it has an immediate cooling effect on the atmosphere. Five main ways to transfer heat from the atmosphere to water and/or land are proposed herein: (1) by direct heat transfer (2) by using compression/expansion of air: (2.1 ) combined with compressed air energy storage; (2.2) combined with energy transport and storage; (2.3) combined with power generation and (3) by a refrigeration cycle. The cases (2.1-2.3) are based on the thermodynamic principle that when an ideal gas is compressed (i.e. , its pressure is increased), it generates heat energy, while when gas is expanded (i.e., its pressure is decreased), it consumes heat energy. The compressors and expanders may be isothermal or adiabatic. The general schemes of cases (1 and 2) are shown in FIGS. 1 , 6-8.

[0074] The following examples are presented to enable those skilled in the art to understand and to practice embodiments of the present disclosure. They should not be considered as a limitation on the scope of the disclosure, but merely as being illustrative and representative thereof.

[0075] The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the spirit and scope of this disclosure.

[0076] In the drawings in order to simplify the drawings, only those items being specifically described are identified in the drawings.

[0077] 1. Atmospheric cooling by heat exchange

[0078] FIG. 1 shows the simplest way to transfer heat from the atmosphere to water and/or land. The main unit here is a fluid-fluid heat exchanger 10. The heat exchanger 10 is divided into two chambers: the chamber with a cooling fluid 12 and for a heating fluid 11 . These two chambers are separated by a heat exchange divider 13. The cooling fluid enters chamber 12 via port 14 and leaves via port 15. Ambient air for cooling enters chamber 11 via port 16 and the cooled air leaves via port 17. Different potential solutions are shown in FIGS. 2-4. FIG. 2 shows the case when the heat exchanger 21 is located in the cold water and/or or land 22, and the ambient (warm) air 20 is transported (pumped) using a fluid moving device 23 to the heat exchanger 21 . In the heat exchanger 21 , outside of the heat exchanging interface there is water and/or land 22, while inside there is atmospheric air 20. The liquid-air heat exchanger can be omitted in the case when the heat transfer in the pipeline 24, bringing the air down to the cold water and/or land has high enough heat exchange rate to cool the air by the surrounding cold water and/or land. The cooled air 25 leaves the heat exchanger and/or the cooling zone22 by a thermally insulated conduit 26. FIG. 3 shows the case when the heat exchanger 30 is located in the atmosphere 20, and the cooling water is pumped using a fluid moving device 31 to the heat exchanger. The cooling water is brought to the device 31 via a flid conduit 32 which may have thermal insulation 33. Another possibility (FIG. 4) is to use a fluid coolant 40, circulating between the cold water or cold land location 41 and the air-heat transfer fluid heat exchanger 42. The liquid-liquid heat exchanger 45 can be omitted in the case when the heat transfer in the fluid conduit 43, bringing the fluid coolant 40 to the cold water and/or land 41 has high enough heat exchange rate to cool the fluid coolant by the surrounding cold water and/or land 41 . The atmospheric air 20 in heat exchangers 30 in FIG. 3 and 40 in FIG. 4, as well as in the other FIG.s containing a heat exchanger with atmospheric air at the outside, may be moved using a fan or another fluid moving devise.

[0079] In the case of heat exchange between the atmosphere and water and/or land, the temperature of cold water and/or land (heat sink) must be lower than that of the atmospheric air (heat source). It is well known that the ocean temperature decreases as the dept increases, reaching approx. 20°C at 50 m depth and a minimum of approximately 4-6°C at depths approximately 500 m and below, and can be used as a heat sink. Another heat sink may be groundwater and/or land. The temperature of groundwater at 1-3 meters below the surface and more is approximately equal to the year-round average temperature of the atmosphere at the same location. In general, cooling of the atmosphere can be achieved only when the air temperature is higher than the groundwater and/or land temperature. That temperature difference depends on the season and/or the time of the day. Since in general, the atmospheric air is located away from the cooling water and/or land, it is necessary to use fluid transport energy to move either air; or water or a coolant fluid to the heat exchanger via fluid moving device such as pump.

[0080] 2. Atmospheric cooling by compression/expansion of air [0081] As mentioned above, atmospheric cooling can be combined with other useful features such as: energy storage, energy transport or mechanical/electric energy generation, respectively. In these cases, isothermal compressor/expander (ItC/E) can used as a compressor and/or expander, where heat released by the process of gas compression is transferred to water and/or land, while the heat consumed during the process of gas expansion is drawn from the atmosphere. In that case the overall heat balance of the proposed system shows that heat is ultimately transferred from the atmosphere to water and/or land, which results in cooling (temperature decrease) of the atmosphere. That is combined with a temperature increase of water and/or land. However, the temperature increase of water and/or land is around three orders of magnitude lower than the temperature decrease of the atmosphere due to the much mass and larger specific heat capacity of water and land.

[0082] FIG. 5 shows the case when the heat transfer from atmosphere to water and/or land is done by using compression in compressor 51 and expansion in expander 52 of a gas such as ambient air 53. During the process of gas compression, heat 54 generated by the compressing gas is transferred to water and/or land 55, while heat 56 consumed by the expanding gas in the expander 52 is supplied from the atmosphere 57. The difference between cases 2.1 , 2.2 and 2.3 is mainly in the type of the auxiliary unit 58 (FIG. 5) and in the mechanical connectivity of the compressor 51 and expander 52.

[0083] In FIG. 6, the auxiliary unit 61 is a compressed air vessel, used for energy storage. That will be discussed in detains in 2.1 below.

[0084] FIG. 7 shows the case when heat removal from the atmosphere is combined with energy transport. In that case, the air storage vessel, shown in FIG. 7 has the shape of a long pipe 71 . The pipe is used for both energy storage and transporting energy in the form of compressed air from the site of compression to the site of expansion. The length of the pipe can be anywhere between zero and thousands of kilometers.

[0085] FIG. 8 shows the case when the processes of compression and expansion are used for electric power generation. In that case the temperature of the heat sink (water and/or land) 85 must be lower than temperature of the heat source (atmosphere) 87. The process of expansion is carried out at close to ambient atmospheric temperature (thigh), while compression is performed at close to water and/or land temperature, which is lower (tiow) than that of expansion. The compressor and expander may be supplied by linear or rotational mechanical energy, such as produced by an electric motor, and the compressor and expander may or may not have a common shaft or common crankwheel, as shown in FIG. 8.

[0086] FIG. 9 shows the case when electricity generation is combined not only with atmospheric cooling, but also with compressed air energy storage. The energy is stored in the compressed gas vessel 91 .

[0087] It is preferable to perform the processes of gas compression and expansion under close to isothermal conditions. Recently a device was patented for the isothermal compressed air energy storage referred to here as ItCAES (shown in PCT application PCT/CA2016/051395 and issued as US 10,527,065). Here is a brief explanation of the ItCAES: The variable pressure vessel shown therein is based on a unique type of isothermal compressor/expander, abbreviated here as ItC/E. When operating as a compressor, the unit is referred to as ItC, while when it operates as an expander, it is referred to as ItE. During energy storage of electricity, ambient air is compressed isothermally in ItC, and the compressed air is stored in either an engineered vessel or underground cavern. When electricity is needed back (re-electrification), compressed air is expanded isothermally by the ItE, generating mechanical energy and further, electricity. According to PCT/CA2016/051395, during the process of isothermal compression in ItC (FIG. 10), heat energy 1011 is generated by the compressing gas 1001 and is transferred to the surroundings 1002 in order to keep the compressing gas temperature close to constant. The operation of the ItC is as follows. First, electrical energy is transferred to mechanical using a motor 1003, then the crankwheel 1004 transforms the rotational motion to linear. The linear motion runs the piston 1005 of a hydraulic cylinder 1006. During the compression cycle, the hydraulic piston moves towards the exit of hydraulic fluid 1007, connected by a fluid conduit 1008 to the compression-expansion (C/E) vessel 1009. The C/E vessel is divided into two zones by a flexible barrier 1010, having a hydraulic fluid at the inside 1011 and air at the outside 1001. When the hydraulic piston 1005 moves towards the exit of the hydraulic fluid 1007, the latter is transferred into the hydraulic fluid zone 1011 of the C/E vessel, where it displaces and compresses air 1001 . The compressed air may fill a compressed air storage vessel 1012. During the process of isothermal expansion in ItE (FIG. 11 ), heat energy 1102 is consumed by the expanding gas 1101 and heat is transferred from the surroundings to the expanding gas in order to keep its temperature constant. When compressed air 1103 enters the air compartment 1101 , when it expands, it displaces the hydraulic fluid 1107 and pushes it into the hydraulic cylinder 1106. As a result, the hydraulic piston 1105 moves to the left (in FIG. 11), generating mechanical energy, which may be transformed to electrical energy by an electric generator. The latter may be converted to electrical energy in a generator 1107. [0088] In general, the process of ideal gas compression consumes mechanical energy, while the process of gas expansion generates mechanical energy. Under ideal isothermal conditions (no energy losses), both the amount of mechanical energy consumed in compressor 51 and the amount of mechanical energy generated in expander 52 (Fig. 5) are proportional to the absolute temperature (in degree Kelvin or Rankine) of the compressing and expanding gas, respectively.

Therefore, if compression and expansion are carried out at the same temperature, the amounts of consumed and generated mechanical energy are equal, and the ideal net mechanical energy balance of the system is zero. In that case the system does not need external mechanical energy input to drive the process of atmospheric cooling. However, under real conditions there are always some energy losses, and they need to be compensated by a mechanical energy input.

For example, if the energy loss is 6%, and we are transferring 1 MJ of heat energy between the atmosphere and the ocean, the system will need to be supplied with 60 kJ of mechanical energy or the equivalent amount of electricity.

[0089] In the case when the temperature of compression is higher than that of expansion, the mechanical energy input (consumption) will be higher than mechanical energy generation. Therefore, even under ideal conditions, mechanical energy needs to be added to the system to balance energy. That energy input should be added to the amount of energy loss in the real system.

[0090] When the compression temperature is lower than the expansion one in an ideal system, the amount of mechanical energy consumption during compression will be lower than the amount of mechanical energy generated during expansion. Thus, the overall system becomes a net generator of mechanical energy in addition to being an atmospheric cooler. In a real system, when the net amount of mechanical energy generated is higher than energy losses, the overall system is a net generator of mechanical energy which may be easily converted to electricity. For example, a system is installed in a tropical location. Under ideal conditions, if the compressor can be cooled by sea water taken from 500 m under the sea level having a temperature of approx. 5°C, and the expander is operating at the ambient air temperature of 26°C, there will be 7% more energy generated that consumed. That means that if 1 MJ of heat energy is transferred from the atmosphere to sea, there will be a generation of 70 kJ of mechanical energy, which can be converted to electricity with high efficiency. That situation is used in system #2.3 below.

[0091] Since true isothermal process is not achievable in real life, the term “isothermal” will be used here to describe not only the ideal process but also near-isothermal real conditions. Here the word “heat” is used as a synonym to “sensible heat” unless indicated otherwise. The word “gas” in this text can mean air or another gas. Mechanical energy can be supplied to the compressor and produced by the expander either using rotational or linear devices.

[0092] Since ItC and ItE (described in PCT/CA2016/051395) have very high thermodynamic isothermal efficiency, often exceeding 98%, they will be used in this application as examples of isothermal compressor and expander, respectively.

[0093] It should be noted that more than one ItC/E unit can be connected to a single crank wheel.

[0094] 2.1 Atmospheric cooling combined with energy storage

[0095] The unit shown schematically in FIG. 6 can be used, in addition to cooling the atmosphere, for storing energy. The auxiliary unit 58 in FIG. 5 in this case is a compressed air vessel 61 in FIG. 6. In that case the temperature of water and/or land does not necessarily need to be below the atmospheric temperature, but the round-trip efficiency of energy storage decreases when the difference between the temperature of the heat source (atmosphere) and the heat sink (water and/or land) decreases. As it is shown above, negative efficiency (net mechanical energy loss) happens in the ideal system when temperature of the atmosphere is lower than temperature of the heat sink. In that case mechanical/electrical energy must be supplied to the system to maintain energy balance and also to cover mechanical losses. The general scheme where there are individual ItC 1202 and ItE 1201 is shown in FIG. 12. There may be two (1203 and 1204) (FIG. 12) or one (1301 ) (FIG. 13) electric motors/generators. Heat is generated and transferred to a heat sink (1206) in ItC 1202 while heat is consumed and transferred from air (1205) in ItE 1201. Either one or two motor/generators can be used in any of FIG.s 12-19. The hydraulic cylinders shown in FIG.s 10-19 can be single- or double-acting. In the case of double-acting cylinders, the hydraulic fluid at each side of the piston operates the same way as in the case of a single-acting cylinder, but they are shifted in time.

[0096] It must be underlined that the rotating motor/generator with the crank wheel can be replaced with a linear motor/generator or other system providing rectilinear motion in FIG.s 10-28. The hydraulic cylinders may be replaced by hydraulic motors.

[0097] The heat consumed during gas expansion 1205; 1305 is obtained from the atmosphere, while the heat generated during gas compression 1206; 1306 is transferred to water and/or land as heat sinks (FIG. 12 and 13). [0098] One example of the transfer of heat from the atmosphere to the expanding gas 1401 is shown in FIG. 14. In that case the heat is exchanged between the atmosphere and the expanding gas via the bare external expander wall 1402.

[0099] In the case when the external heat transfer rate outside of the bare expansion vessel wall 1402 is not sufficient to maintain close to isothermal conditions, extended heat transfer surfaces such as, but not limited to fins 1501 , may be used as shown in FIG. 15.

[0100] For a further increase in the heat transfer rate from the atmosphere to the expanding air, an external heat exchanger 1601 (which may be similar to a car radiator) can be used as shown in FIG. 16. A heat-exchange fluid 1603 circulates between a jacket 1604 surrounding the external surface 1605 of the C/E vessel 1606 and the heat exchanger 1601. The heat exchanger 1601 transfers heat from ambient air (the atmosphere)1607 to the heat-exchange fluid 1603, which further transfers heat to the expanding air 1608. In this case the external (air-side) surface of the heat exchanger may be significantly increased by installing heat exchanger fins 1602. As mentioned above, an air moving device such as fan may be used to increase the air-heat exchanger heat transfer rate.

[0101] Another possibility for transferring heat from the atmosphere 1701 to the expanding air 1702 in ItE 1703 is by using an air-cooling jacket 1704 outside of the C/E vessel, fed by ambient air (FIG. 17).

[0102] It should be noted that even if the heat transfer rate between the expanding gas and the atmosphere is not sufficient to maintain close to isothermal conditions, i.e., the fully expanded gas has a temperature lower than that of the surrounding atmosphere, the cold expanded gas leaving the expansion vessel will still cool the atmosphere by mixing with it. In that case the expansion will be adiabatic, and the roundtrip energy efficiency of the process of compressed air energy storage as a result will somehow be lower than in the case of isothermal compression and expansion. Therefore, there is a tradeoff between the cost of the air heat exchanger and the energy efficiency of the process.

[0103] The cooling of the compressing gas can be done by heat exchange. There are several possibilities: pumping the cooling liquid (which can be either natural cold water or a circulating cooling fluid) to the compressing gas, when the heat exchange is performed at the ItC; circulating a cooling fluid between the ItC and the cold water and/or land, when the heat exchanger is immersed in the cold water and/or land, or pumping both when the heat exchanger is located away from the ItC and the cold water. FIG. 18 shows the process of cooling the compressing gas by pumping cooling water 1801 , such as ocean/sea/lake/river water or groundwater, to a cooling jacket 1803, surrounded by a layer of heat insulation 1804. The pipe carrying the cooling water 1802 can be thermally insulated. FIG. 19 shows the case of cooling the compressing gas 1901 by a circulating cooling fluid 1902 which is re-cooled in a heat exchanger 1903 located underground or under water 1904. The cooling jacket and its insulation are similar to those shown in FIG. 18. Thus, the temperature of the compressing gas in the ItC is maintained close to constant and close to that of the heat sink (cold water and/or land). Overall, heat is transferred from the compressing gas to water and/or land.

[0104] FIG. 20 shows the case when the compression and expansion are carried out in one single ItC/E unit. The C/E vessel has a cooling/heating jacket 2001 which is used to transfer heat to the expanding air 2002 during the process of air expansion in the air chamber of the C/E vessel and remove heat from the compressing air 2002 during the process of compression. A heating (air) or cooling fluid circulates between the jacket and the surroundings during the expansion and compression phases, respectively. When the C/E vessel 1200 operates as a compressor, three-way valves 2005 and 2006 connect the cooling/heating jacket 2001 with the cooling fluid 2009, such as natural water (as in FIG. 18) or a circulating cooling fluid (as in FIG. 19). During the process of gas expansion, valves 2005 and 2006 connect the heating/cooling jacket to the atmosphere. Ambient air 2007 is pumped (pump not shown) to the jacket 2001 and then the cooled air 2008 is exhausted to the atmosphere. FIG. 21 shows the case similar to that in FIG. 20, but the heat being transferred from the ambient air 2000 to the expanding gas 2102 via heat exchanger 2101 , similar to a car radiator. In all the air heat exchangers shown here, ambient air 2100 may or may not be pushed towards the heat exchanger using a gas moving device such as a fan (similar to a car radiator fan).

[0105] When air needs to be compressed to high pressure, for example above approximately 30 bar, a two-stage hydraulic cylinder system would be preferable in order to avoid excessive forces on the hydraulic piston rods. In that case, each of the hydraulic cylinders for compression and expansion shown in FIG.s 10-21 , can be replaced by a pair of single- or double-acting hydraulic cylinders with different diameters (2.1 and 2.2, FIG. 22). The larger diameter cylinder 2.1 will represent the first stage of compression, while the smaller diameter cylinder 2.2 will represent the second stage of compression. Both hydraulic cylinders are driven together by a common shaft 93. The connections between the pair of double-action hydraulic cylinders for the case of gas compression (ItC) is shown in FIG. 22. The larger hydraulic cylinder 2.1 is connected to both the smaller hydraulic cylinder 2.2 and the low-pressure compression/expansion (C/E) vessels 97. The smaller hydraulic cylinder 2.2 is also connected to the high-pressure compression/expansion vessels 96. Each pair of low pressure and high-pressure compression/expansion vessels are connected between them using check valves 95. The connections between the pair of double-acting hydraulic cylinders for the case of gas expansion is shown in FIG. 22. The valves 94 are solenoid valves, allowing a certain amount of compressed air to enter the compression/expansion vessels 96. The solenoid valve 94 opens approximately at the time when the volume of the hydraulic cylinder, connected to the compression/expansion vessel is minimal, and closes when the appropriate volume of compressed gas fills the expansion vessel 97. The volume of compressed gas entering the compression/expansion vessel (and therefore, the time of opening the solenoid valve 94) is calculated so that the pressure at the end of the expansion cycle (when the volume of the hydraulic cylinder, connected to the compression/expansion vessel, is maximal) is close to the ambient pressure where the compression/expansion vessel discharges air (“air out” in FIG. 23).

[0106] As mentioned above, in each of the processes of gas compression and expansion, the heat is removed from, or introduced to the gas, respectively, through the wall of the compression/expansion vessel. In some cases, however, when large amounts of heat need to be transferred through the vessel wall, the surface of the bare wall is not large enough to transport all the heat produced by, or consumed from the compressing or expanding gas, respectively. In that case, it is necessary to provide elements having extended heat transfer area to the inside and/or outside surface of the bare vessel wall. Different ways to improve the outside heat transfer of the ItC/E between its external surface and the ambient air are shown in FIGS. 14-17. Below, extended heat transfer area elements at the inner surface of the vessel wall will be disclosed.

[0107] This disclosure proposes the use of flat sheets of thermally conductive materials placed between the inner cylinder wall of the compression and expansion vessel and the flexible bladder dividing hydraulic fluid from compressing or expanding air. The design of the extended heat transfer area elements disclosed here provides high heat transfer rate.

[0108] FIG. 24A and FIG. 24B show the compression/expansion vessel 2400 having internal surface 2401 and a flexible bladder 2402, with extended internal heat transfer area elements 2403. It should be noted that the number and position of the ports 2404 connected to a real vessel may be different from these shown in FIG. 24A and 24B.

[0109] In the embodiment shown in FIG. 24A and 24B, a flat sold sheet or a mesh 2403 is located between the internal compression/expansion vessel surface 2401 and the flexible bladder 2402. The sheet 2403 can have a tubular shape or can be a rolled piece of a flat material. The sheet is made of material having high thermal conductivity and preferably high heat capacity such as carbon-based material for example graphite, or metal, for example, but not limited to steel, stainless steel, copper, brass, bronze, aluminum. The type of the sheet can be, for example a non-perforated or perforated sheet, wire cloth, expanded metal, non-woven fibrous sheet or another. It is advantageous if the heat transfer sheet 2403 extends towards the center of the compression/expansion vessel when the flexible bladder is retracted and moves towards the wall of the compression/expansion vessel when the flexible bladder is expanded. That can be achieved, for example, if the flat sheet has the shape and the mechanics of a spring. [0110] 2.2 Atmospheric cooling combined with energy transport

[0111] FIG. 7 shows the case when the compressed air storage tank has a cylindrical shape, where its diameter is significantly smaller than the length, forming a pipe. In that case, the compressed air tank is used not only for the storage of the compressed air, but also for the energy transport by moving the compressed air from the input of the cylindrical pipe toward its exit. In the case of energy transport, the heat management of the ItC (at the pipe input) and ItE (at the pipe output) is performed the same way as described in FIG.s 14-18.

[0112] When atmospheric cooling is combined with energy transport, the temperature of the atmosphere (heat source) does not need to be higher than the temperature of the heat sink.

[0113] However, the greater the temperature difference between the heat source (atmosphere) and the heat sink (water and/or land), the greater the round-trip efficiency of the process of energy storage, as shown above.

[0114] 2. 3 Atmospheric cooling combined with electric power generation

[0115] It is well known that temperature difference in physical objects can be used to transform heat energy into mechanical energy, and further - to electricity. That is the general working principle of thermal power plants. In conventional thermal power plants (such as coal, natural gas and nuclear), the higher temperature is above the ambient one and is provided by the fuel, while the lower temperature is slightly higher than that of the environment (usually air and/or water), and therefore heat flows from the heated object (usually fluid) to the ambient atmosphere or water, thus heating them. However, there is also a process, where the higher temperature is that of the environment (usually surface water), while the lower temperature is that of deep ocean water. The process was first proposed at the end of 19th century to use the difference between ocean water temperatures at different depths for the generation of mechanical and electric energy. Therefore, in that case heat flows from surface water to the depths of the ocean. Based on the temperature difference of approximately 20°C between the surface of the ocean in tropical altitudes and depth below approximately 500 m, the ideal (Carnot) conversion efficiency of thermal to mechanical energy is around 7%. So far, mostly vapor-based thermodynamic cycles such as organic Rankine cycle were proposed and tested in that technology [OES (2022), using sea water for heating, cooling and power generation [www.ocean-energy-systems.org]. Actual efficiencies of only 2-3% have been reported, mostly due to the losses in vapor cycles.

[0116] An example is disclosed herein to use the highly efficient ItC/E unit for the generation of mechanical/electric energy from the differences in temperature between the atmosphere and ocean water at depths of several hundred meters. The high-efficiency power generation is combined with atmospheric cooling, as heat flows from ambient air to the ocean depths. The system disclosed here is similar to the two systems described above (#2.1 and #2.2). The main differences are that the atmospheric temperature in this section (#2.3) is always higher than the temperature of the heat sink (water and/or land); the compression temperature (that of a cold water) is lower that the atmospheric temperature, and therefore mechanical energy is generated and can be further converted to electricity. The general schematics is shown in FIGS. 8 and 9.

[0117] FIG. 25 shows the disclosed system, including its fluid and heat flows. When the crank wheel moves the hydraulic piston towards the right, the air in the compression vessel is compressed, thus generating heat. The latter is transferred via heat exchange to the low-temperature heat sink (water and/or land), as shown with an orange arrow. At the same time, the air in the expansion vessel is being expanded, thus consuming heat. Heat from the high-temperature heat supply (atmospheric air) is introduced to the expanding air via heat exchange, thus cooling the atmosphere. In addition to transferring atmospheric heat to the expansion vessel, atmospheric heat may be used to heat the compressed air in the compressed air storage vessel and/or in the pipelines between the compression vessel and the expansion vessel, as shown with orange arrows. Therefore, in general, heat from the atmosphere is transferred to the lower- temperature water and/or land, thus decreasing the atmospheric temperature. Because of the great difference between the specific heats of the heat source (air) and the heat sink (water/land), the temperature decrease of the atmosphere will be significantly greater than the temperature increase in the ocean water and/or land.

[0118] FIG. 25 shows an example of the working half-cycle of the unit when mechanical energy is generated. In that half-cycle, the piston 2501 in a double-acting hydraulic cylinder 2502 moves towards the ItC. This causes the hydraulic fluid to enter the C/E vessel of the compressor 2503, thus compressing air 2504 and filling the compressed air storage tank 2505 with compressed air. At the same time, the compressed air from 2505 is entering C/E vessel of the expander 2506, displacing hydraulic fluid 2507 from C/E vessel 2506 towards the left side of the double-acting hydraulic cylinder. Since the compressing air pressure at temperature tiow (in C/E vessel 2503) is lower than the expanding air pressure at thigh (in C/E vessel 2506), the net force on the hydraulic piston 2501 is directed from left to the right, thus generating mechanical energy. The linear mechanical energy is converted to a rotational one using the crank wheel 2508, and then it can be converted to electric energy in the generator 2509. During the air compression in C/E vessel 2503, the generated heat 2512 is transferred to the heat sink 2510 using a cooling jacket 2511 . At the same time, during the air expansion in the C/E vessel 2506, the consumed heat 2513 is provided from the atmosphere 2514. In addition, ambient air may be used to heat the compressed air in compressed air storage vessel 2505 and/or the pipeline between the C/E vessel 2503 and the compressed air storage vessel and/or in the pipeline between the compressed air storage vessel and C/E vessel 2206. The heat flows are shown schematically with dotted lines and arrows in FIG. 25. FIG. 26 shows the half-cycle when both the expansion vessel 2601 and the compression vessel 2602 are open to the atmosphere via the valves 2604 and 2605, respectively. Hydraulic piston 2606 moves from right to left. That leads to the removal of the exhaust air from the expansion vessel 2601 and to filling the compression vessel 2602 with fresh air 2607 by opening the valves 2604 and 2605, respectively.

[0119] Heat transfer elements in the case when the heat transfer fluid, connecting the heat sink 2701 and the compression vessel 2702, is air 2703, are shown in FIG. 27. The air 2703 entering the compression vessel 2702 is cooled in a heat exchanger 2704, located in the heat sink (cold water and/or land) at temperature tiow. Alternatively, the air may be cooled without a heat exchanger, through the walls of the piping 2707 in the heat sink 2701 . The cooled air enters the cooling jacket 2707 of the compression vessel 2702, thus maintaining constant and close to tiow the temperature of the compressing gas 2706. The air compartment 2706 of the compression vessel 2702 may be fed with air either directly from the atmosphere (not shown on the FIG.), or by the cooled air 2703 coming from the heat sink. After leaving the compression vessel, the compressed gas at a temperature of tiow (the temperature of the heat sink) may be heated in the pipe connecting it with the expansion vessel using a gas-gas heat exchanger 2710. The heat transfer from the ambient air to the expanding gas is done through the external wall of the expanding vessel. Alternatively, the heat exchange between the expanding gas and the ambient air (the external heat exchange) can be done the same way as shown in FIGS. 14-17 and/or 24.

[0120] Alternatively, the compressed gas vessel in the system described in FIG. 27 may be eliminated (FIG. 28). In that case, the compressed gas produced by the isothermal compressor is directly connected to the compressed gas inlet of the isothermal gas expander via conduit 2801 . The water/air heat exchanger in FIG.s 27 and 28 may be eliminated in the case when the heat exchange through the wall of the down-coming pipe, carrying the air, is enough to exchange heat between the air and cold water.

[0121] The gas-gas heat exchanger 2710 may be omitted (FIG. 29).

[0122] FIG. 30 shows the case when the heat transfer fluid for the heat sink is the cold water 3001 (the heat sink). In that case, the cold water at temperature tcold is pumped to the ItC/E via heat-insulated fluid circuit 3002, where it may be used to cool the incoming air to the compression vessel and enters the cooling jacket 3003 to cool the compressing gas 3004. The heat exchanger cooling the incoming air to the compression vessel in some cases may be omitted.

[0123] In FIG. 31 , a cooling fluid 3101 , circulating between the heat sink 3102 and the compression vessel 3103, is used to cool the compressing gas 3104. The heat sink/cooling fluid heat exchanger 3105 may be eliminated in the case when the heat exchange through the wall of the down-coming pipe 3106, carrying the cooling fluid, is enough to exchange heat between the cooling fluid and cold water.

[0124] The ItC/E in this patent was assumed to be close to the theoretical (true) isothermal compressor and expander. FIG. 32 shows the change of temperature during 90 minutes of compression. The temperature of the compressed gas leaving the ItC, did not change significantly during that time, and also between the compressed gas and the surrounding air. This result proves that the ItC/E is very close to an isothermal device.

[0125] Referring to FIGS. 1 to 4, a heat exchange process includes the steps of: providing a heating fluid to a heat exchange device, the heating fluid having a temperature; providing a cooling fluid to the heat exchange device; cooling the heating fluid in the heat exchange device to produce cooled fluid; heating the cooling fluid in the heat exchange device to produce heated fluid, the heated fluid having a temperature; exhausting the cooled fluid into the atmosphere; transferring the heated fluid into a cooling medium wherein the cooling medium is one of land and water, the cooling medium having a temperature; and wherein the temperature of the cooling medium is at least 0.1 °C less than the temperature of heated fluid.

[0126] The temperature of the cooling medium may be at least 0.2°C less than the temperature of the heating fluid.

[0127] The heat exchange device may be a heat exchanger. [0128] The heat exchanger may be located in the cooling medium. The cooling fluid may be provided from the cooling medium. The heating fluid may be pumped into the heat exchanger. An insulated conduit for exhausting the cooled air from the heat exchanger into the atmosphere.

[0129] The heating fluid may be air from the atmosphere.

[0130] The heating fluid may be a first heating fluid and the heat exchanger may be a first heat exchanger and the step of cooling the heating fluid in a heat exchanger to produce a cooled fluid may be the step of cooling a first heating fluid in the first heat exchanger to produce a first cooled fluid and further including the steps of providing a second heating fluid being air from the atmosphere and cooling the second heating fluid in a second heat exchanger to produce the cooled fluid.

[0131] Referring to FIGS. 5 to 9, the heat exchange device may include multiple devices including a gas compressor and a gas expander and wherein heat exchange is a bi-product of gas compression and gas expansion and further including the steps of: providing gas; compressing the gas in the gas compressor to produce compressed gas; wherein the cooling fluid may be provided to the gas compressor; transferring the compressed gas to an auxiliary unit; transferring the compressed gas from the auxiliary unit to the gas expander; wherein the heating fluid may be provided to the gas expander; and exhausting the expanded gas.

[0132] The auxiliary unit may be a compressed gas vessel. The compressed gas vessel may be used to store energy. The compressed gas vessel may bean elongate pipe. The elongate pipe may be used to transport and store energy. The elongate pipe has a length and the length may be up to at least a thousand kilometers.

[0133] The step of compressing the gas consumes power.

[0134] The step of expanding the compressed gas generates power.

[0135] The gas compressor and the gas expander may have one of a common shaft and a common crank wheel.

[0136] The step of expanding the compressed gas may be carried out at ambient temperature.

[0137] The step of compressing the gas may be carried out at the temperature of the cooling medium.

[0138] Referring to FIGS. 12 to 31 , an energy storage system includes a storage tank, a gas expander, and a gas compressor.

[0139] The gas expander includes an expander’s hydraulic cylinder, an expander’s variable pressure vessel. The expander’s hydraulic cylinder has a variable working volume responsive to motion of a piston and, wherein the variable working volume of the expander’s hydraulic cylinder increases during an expander’s first stroke and the variable working volume of the expander’s hydraulic cylinder decreases during an expander’s second stroke. The expander’s variable pressure vessel has a volume and being operably connected to the expander’s hydraulic cylinder and operably connected to the storage tank. The expander’s variable pressure vessel includes an expander’s liquid chamber and an expander’s gas chamber. The expander’s liquid chamber has a variable volume that decreases responsive to the expander’s first stroke and increases responsive to the expander’s second stroke. The expander’s gas chamber has a variable volume that increases responsive to the expander’s first stroke and decreases responsive to the expander’s second stroke, the expander’s gas chamber has an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough. A heating fluid such that during expansion, cooled fluid from the heating fluid is transferred through the outer wall of the expander variable pressure vessel and a cooled fluid is produced that is exhausted into the atmosphere. A moveable barrier between the expander liquid chamber and the expander gas chamber such that movement of the moveable barrier causes the volume in the expander liquid chamber and the volume in the expander gas chamber to displace each other and the volume in the expander gas chamber plus the volume in the expander liquid chamber is generally constant and generally equals the volume in the expander variable pressure vessel.

[0140] The gas compressor includes a compressor’s hydraulic cylinder and a compressor’s variable pressure vessel. The compressor’s hydraulic cylinder has a variable working volume responsive to motion of a piston. The variable working volume of the compressor’s hydraulic cylinder increases during a compressor’s first stroke and the variable working volume of the compressor’s hydraulic cylinder decreases during a compressor’s second stroke. The compressor’s variable pressure vessel has a volume and being operably connected to the compressor’s hydraulic cylinder and operably connected to the storage tank. The compressor’s variable pressure vessel includes a compressor’s liquid chamber and a compressor’s gas chamber. The compressor’s liquid chamber has a variable volume that decreases responsive to the compressor’s first stroke and increases responsive to the compressor’s second stroke. The compressor’s gas chamber has a variable volume that increases responsive to the compressor’s first stroke and decreases responsive to the compressor’s second stroke. The compressor’s gas chamber has an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough. A cooling fluid such that during compression, heat is produced and the heat is used to heat the cooling fluid to produce heated fluid that is transferred to a cooling medium. The cooling medium is one of land and water. A moveable barrier between the compressor’s liquid chamber and the compressor’s gas chamber. Movement of the moveable barrier causes the volume in the compressor’s liquid chamber and the volume in the compressor’s gas chamber to displace each other. The volume in the compressor’s gas chamber plus the volume in the compressor’s liquid chamber is generally constant and generally equals the volume in the compressor’s variable pressure vessel.

[0141] The energy storage system may include an energy conversion device operably connected to the expander’s hydraulic cylinder and operably connected to the compressor’s hydraulic cylinder.

[0142] The energy conversion device may be an electric generator.

[0143] A first energy conversion device may be operably connected to the expander’s hydraulic cylinder and a second energy conversion device operably connected to the compressor’s hydraulic cylinder. The first energy conversion device may be an electric generator and the second energy storage device may be an electric motor.

[0144] The heating fluid may be ambient air.

[0145] The energy storage system may include fins operably connected to the thermally conductive portion of the outer wall of the expander’s variable pressure vessel. [0146] An expander’s cooling jacket may be operably connected to the thermally conductive portion of the outer wall of the expander’s variable pressure vessel and wherein the heating fluid may be in the expander’s cooling jacket.

[0147] A heat exchanger has an inlet and an outlet and the heat exchanger inlet may be in fluid communication with the cooling jacket and the heat exchanger outlet may be in fluid communication with the cooling jacket.

[0148] A compressor’s cooling jacket may be operably connected to the thermally conductive portion of the outer wall of the compressor’s variable pressure vessel and wherein the cooling fluid may be in the compressor’s cooling jacket. The compressor’s cooling jacket may have an inner surface and an outer surface. The inner surface may be in thermal communication with the outer wall of the compressor’s variable pressure vessel. A thermal insulation layer may be in thermal communication with the outer surface of the compressor’s cooling jacket. A conduit may be in fluid communication with the cooling jacket and a pump may be operably connected to the conduit. The cooling fluid may be provided to the conduit.

[0149] The cooling fluid may be water from one of an ocean, a sea, a lake, a river, and groundwater.

[0150] The expander and compressor may be a combination expander/compressor.

Claims

1 . A heat exchange process comprising the steps of: providing a heating fluid to a heat exchange device, the heating fluid having a temperature; providing a cooling fluid to the heat exchange device; cooling the heating fluid in the heat exchange device to produce cooled fluid; heating the cooling fluid in the heat exchange device to produce heated fluid, the heated fluid having a temperature; exhausting the cooled fluid into the atmosphere; transferring the heated fluid into a cooling medium wherein the cooling medium is one of land and water, the cooling medium having a temperature; and wherein the temperature of the cooling medium is at least 0.1 °C less than the temperature of heated fluid.

2. The heat exchange process as claimed in claim 1 wherein the temperature of the cooling medium is at least 0.2°C less than the temperature of the heating fluid.

3. The heat exchange process as claimed in claim 1 or 2 wherein the heat exchange device is a heat exchanger.

4. The heat exchange process as claimed in claim 3 wherein the heat exchanger is located in the cooling medium.

5. The heat exchange process as claimed in claim 4 wherein the cooling fluid is provided from the cooling medium.

6. The heat exchange process as claimed in claim 4 or 5 wherein the heating fluid is pumped into the heat exchanger.

7. The heat exchange process as claimed in any one of claims 4 to 6 further including an insulated conduit for exhausting the cooled air from the heat exchanger into the atmosphere.

8. The heat exchange process as claimed in any one of claims 1 to 7 wherein heating fluid is air from the atmosphere.

9. The heat exchange process as claimed in any one of claims 3 to 7 wherein the heating fluid is a first heating fluid and the heat exchanger is a first heat exchanger and the step of cooling the heating fluid in a heat exchanger to produce a cooled fluid is the step of cooling a first heating fluid in the first heat exchanger to produce a first cooled fluid and further including the steps of providing a second heating fluid being air from the atmosphere and cooling the second heating fluid in a second heat exchanger to produce the cooled fluid.

10. The heat exchange process as claimed in claim 1 wherein the heat exchange device includes multiple devices including a gas compressor and a gas expander and wherein heat exchange is a bi-product of gas compression and gas expansion and further including the steps of: providing gas; compressing the gas in the gas compressor to produce compressed gas; wherein the cooling fluid is provided to the gas compressor; transferring the compressed gas to an auxiliary unit; transferring the compressed gas from the auxiliary unit to the gas expander; wherein the heating fluid is provided to the gas expander; and exhausting the expanded gas.

11. The heat exchange process as claimed in claim 10 wherein the auxiliary unit is a compressed gas vessel.

12. The heat exchange process as claimed in claim 11 wherein the compressed gas vessel is used to store energy.

13. The heat exchange process as claimed in claim 11 wherein the compressed gas vessel is an elongate pipe.

14. The heat exchange process as claimed in claim 13 wherein the elongate pipe is used to transport and store energy.

15. The heat exchange process as claimed in claim 14 wherein the elongate pipe has a length and the length is up to at least a thousand kilometers.

16. The heat exchange process as claimed in any one of claims 10 to 15 wherein the step of compressing the gas consumes power.

17. The heat exchange process as claimed in claim in any one of claims 10 to 15 wherein the step of expanding the compressed gas generates power.

18. The heat exchange process as claimed in claims 16 or 17 wherein the gas compressor and the gas expander have one of a common shaft and a common crank wheel.

19. The heat exchange process as claimed in any one of claims 10 to 18 wherein the step of expanding the compressed gas is carried out at ambient temperature.

20. The heat exchange process as claimed in any one of claims 10 to 19 wherein the step of compressing the gas is carried out at the temperature of the cooling medium.

21 . An energy storage system comprising: a storage tank; a gas expander including: an expander’s hydraulic cylinder having a variable working volume responsive to motion of a piston and, wherein the variable working volume of the expander’s hydraulic cylinder increases during an expander’s first stroke and the variable working volume of the expander’s hydraulic cylinder decreases during an expander’s second stroke; an expander’s variable pressure vessel having a volume and being operably connected to the expander’s hydraulic cylinder and operably connected to the storage tank; wherein the expander’s variable pressure vessel includes: an expander’s liquid chamber having a variable volume that decreases responsive to the expander’s first stroke and increases responsive to the expander’s second stroke; an expander’s gas chamber having a variable volume that increases responsive to the expander’s first stroke and decreases responsive to the expander’s second stroke, the expander’s gas chamber having an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough; a heating fluid, wherein during expansion heat from the heating fluid is transferred through the outer wall of the expander variable pressure vessel and a cooled fluid is produced that is exhausted into the atmosphere; and a moveable barrier between the expander liquid chamber and the expander gas chamber, and wherein movement of the moveable barrier causes the volume in the expander liquid chamber and the volume in the expander gas chamber to displace each other and the volume in the expander gas chamber plus the volume in the expander liquid chamber is generally constant and generally equals the volume in the expander variable pressure vessel; a gas compressor including: a compressor’s hydraulic cylinder having a variable working volume responsive to motion of a piston and, wherein the variable working volume of the compressor’s hydraulic cylinder increases during a compressor’s first stroke and the variable working volume of the compressor’s hydraulic cylinder decreases during a compressor’s second stroke; and a compressor’s variable pressure vessel having a volume and being operably connected to the compressor’s hydraulic cylinder and operably connected to the storage tank; wherein the compressor’s variable pressure vessel includes: a compressor’s liquid chamber having a variable volume that decreases responsive to the compressor’s first stroke and increases responsive to the compressor’s second stroke; a compressor’s gas chamber having a variable volume that increases responsive to the compressor’s first stroke and decreases responsive to the compressor’s second stroke, the compressor’s gas chamber having an outer wall wherein at least a portion of the outer wall is thermally conductive and allows heat to transfer therethrough; a cooling fluid, wherein during compression heat is produced and the heat is used to heat the cooling fluid to produce heated fluid that is transferred to a cooling medium wherein the cooling medium is one of land and water; and a moveable barrier between the compressor’s liquid chamber and the compressor’s gas chamber, and wherein movement of the moveable barrier causes the volume in the compressor’s liquid chamber and the volume in the compressor’s gas chamber to displace each other and the volume in the compressor’s gas chamber plus the volume in the compressor’s liquid chamber is generally constant and generally equals the volume in the compressor’s variable pressure vessel.

22. The energy storage system as claimed in claim 21 further including an energy conversion device operably connected to the expander’s hydraulic cylinder and operably connected to the compressor’s hydraulic cylinder.

23. The energy storage system as claimed in claim 22 wherein the energy conversion device is one of an electric generator.

24. The energy storage system as claimed in claim 22 further including a first energy conversion device operably connected to the expander’s hydraulic cylinder and a second energy conversion device operably connected to the compressor’s hydraulic cylinder.

25. The energy storage system as claimed in claim 24 wherein the first energy conversion device is an electric generator and the second energy storage device is an electric motor.

26. The energy storage system as claimed in any one of claims 21 to 25 wherein the heating fluid is ambient air.

27. The energy storage system as claimed in any one of claims 21 to 26 further including fins operably connected to the thermally conductive portion of the outer wall of the expander’s variable pressure vessel.

28. The energy storage system as claimed in any one of claims 21 to 26 further including an expander’s cooling jacket operably connected to the thermally conductive portion of the outer wall of the expander’s variable pressure vessel and wherein the heating fluid is in the expander’s cooling jacket.

29. The energy storage system as claimed in claim 28 further including a heat exchanger having an inlet and an outlet and the heat exchanger inlet is in fluid communication with the cooling jacket and the heat exchanger outlet is in fluid communication with the cooling jacket.

30. The energy storage system as claimed in any one of claims 21 to 29 wherein the compressor’s variable pressure vessel further includes a compressor’s cooling jacket operably connected to the thermally conductive portion of the outer wall of the compressor’s variable pressure vessel and wherein the cooling fluid is in the compressor’s cooling jacket.

31 . The energy storage system as claimed in claim 30 wherein the compressor’s cooling jacket has an inner surface in the thermal communication with the outer wall of the compressor’s variable pressure vessel and an outer surface and further including a thermal insulation layer in thermal communication with the outer surface of the compressor’s cooling jacket.

32. The energy storage system as claimed in claim 31 further including a conduit in fluid communication with the cooling jacket and a pump operably connected to the conduit and the cooling fluid is provided to the conduit.

33. The energy storage system as claimed in claim 32 wherein the cooling fluid is water from one of an ocean, a sea, a lake, a river, and groundwater.

34. The energy storage system as claimed in any one of claims 21 to 33 wherein the expander and compressor are a combination expander/com pressor.