Johnson Environmental Energy Converter

Abstract

An ambient energy converter includes a housing having an upper portion and a lower portion. The housing lower portion has a hydrophobic material portion. The upper portion has a vent opening in fluid communication with an ambient fluid. The housing contains a mass of a hygroscopic solution in the housing lower portion in fluid communication with the hydrophobic material portion. An ion-conducting membrane electrode assembly is coupled to the housing to allow ionized water or water vapor to travel through the ion-conducting membrane electrode and contact the hygroscopic solution. An air conduit may be coupled to the housing to provide an airflow to the ion-conducting membrane electrode and / or the hydrophobic material portion.

Description

[0001] References to related applications

[0002] Applicant claims the benefit of U.S. Provisional Patent Application No. 62 / 975,502, filed on February 12, 2020, and entitled “Johnson Ambient Energy Converter.” Technical Field

[0003] The present invention generally relates to a system for converting thermal energy into electrical energy. Background Art

[0004] There has long been a goal to develop an engine that can harvest thermal energy that is freely available in the surrounding environment. In conventional thermoelectric converters and conventional devices that operate on a thermodynamic cycle, a heat source and a heat sink are used and present simultaneously. They require a simultaneous temperature difference to operate. Attempts have been made to apply the required temperature difference using thermal insulation materials and heat sinks. A section of the converter is thermally insulated from the environment and / or coupled to a high heat capacity material in order to delay changes in its temperature relative to temperature changes in its environment. The lag in temperature changes relative to the section exposed and thermally coupled to the environment produces the necessary temperature difference required for the operation of the thermoelectric converter. However, the need to include heat capacity materials and thermal insulation limits the practicality of such converters. In addition, as parasitic heat conduction through the device structure becomes increasingly significant due to the reduction in the size of the device, the conversion efficiency decreases.

[0005] It can therefore be seen that there remains a need for energy converters which can operate in an environment for the generation of electrical power. It is to the provision of these that the present invention is therefore primarily directed. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1A is a schematic cross-sectional view of an ambient water condenser for use as part of an energy converter in a preferred form of the invention.

[0007] Figure 1 Representative graphs illustrating temperature and humidity variations at randomly selected locations and over a 30-day period.

[0008] Figure 2 It is a graph that illustrates the relationship between ambient water vapor pressure, temperature, relative humidity, and the number of grams of water per unit volume of air.

[0009] Figure 3 It is a graph of saturation temperature and vapor pressure versus the mass percentage of lithium bromide in aqueous solution.

[0010] Figure 4 Yes Description Figure 1The figure shows a graph of the transient enthalpy from coordinates 3,6 to coordinates 2,5 versus temperature and the mass percentage of lithium bromide in the aqueous solution.

[0011] Figure 5 Yes Description Figure 1 The graph of the transient enthalpy from coordinates 11,16 to coordinates 13,17 versus temperature and the mass percentage of lithium bromide in the aqueous solution is shown in FIG.

[0012] Figure 5A It is a graph illustrating the pressure of water versus enthalpy and temperature.

[0013] Figure 6 is a schematic cross-sectional view of an ambient energy converter in a preferred form of the invention.

[0014] Figure 7 yes Figure 6 Schematic cross-sectional view of a portion of a membrane electrode assembly component of an ambient energy converter of FIG. 1 , showing the electrolysis of water into a hygroscopic solution.

[0015] Figure 8 yes Figure 6 Schematic cross-sectional view of a portion of a membrane electrode assembly component of an ambient energy converter showing the electrolysis of water into a hygroscopic solution.

[0016] Fig. 9 is a schematic cross-sectional view of an ambient energy converter in another preferred form of the invention.

[0017] Fig.10 is a schematic cross-sectional view of an ambient energy converter in another preferred form of the invention.

[0018] Fig.11 is a schematic cross-sectional view of an ambient energy converter in another preferred form of the invention.

[0019] Fig.12 is a graph of cell voltage versus current density illustrating water electrolysis and reduction reactions in a fuel cell membrane electrode assembly. DETAILED DESCRIPTION

[0020] The present invention can be driven by normal temperature and humidity transients that occur naturally in the ambient environment. Its operating principle is based on the thermocouple effect, where the voltage of an electrochemical cell varies directly as a function of its temperature and the difference in reactant concentrations. As required by any thermodynamic cycle, a heat source and a heat sink are employed; however, unlike a typical heat engine, the heat source and heat sink are not simultaneous. Ideally, when operating on ambient energy, the entire ambient energy converter maintains a state of thermal equilibrium with its environment.

[0021] Next, referring to the accompanying drawings, Figure 1A 1 shows a basic ambient water condenser or condenser portion of an ambient energy converter 1 in a preferred form of the invention, hereinafter collectively referred to as an ambient energy converter. The ambient energy converter 1 comprises a condensation chamber 10 having an outer wall 10A, which is fluidically coupled to a fluid within a sump or housing 3 through an upper porous hydrophobic membrane 5. The condensation chamber 10 has a lower end coupled to and in fluid communication with a drip tube 12.

[0022] The housing 3 may include an expansion chamber 34 for accommodating changes in the total water content equilibrium state of the hygroscopic electrolyte or solution 8. The expansion chamber 34 may be mechanically expandable, or Figure 1A 3, which may include an excess volume 36 that allows the hygroscopic solution 8 to expand and contract as needed when its average water content varies with ambient humidity conditions. The expansion surplus chamber 34 may also include a vent 38 to allow air to pass through to maintain total pressure equilibrium with the environment when the volume of the hygroscopic solution 8 changes. Under high humidity conditions, when the hygroscopic solution 8 absorbs water from the ambient air through the lower porous hydrophobic membrane 4, the volume of the hygroscopic solution 8 expands to react to the point where the hygroscopic solution 8 in the lower section 2 has a water vapor pressure equal to the water vapor partial pressure of the ambient air. Conversely, under low humidity conditions, when water evaporates from the hygroscopic solution 8, the hygroscopic solution 8 contracts until the hygroscopic solution 8 reaches a water vapor pressure equal to the water vapor partial pressure of the ambient air. Under very high humidity conditions where the hygroscopic solution 8 absorbs more water than could otherwise be accommodated within the housing 3, the expansion surplus chamber 34 protects the ambient energy converter 1.

[0023] The housing 3 has a housing lower or bottom section 2 and a housing upper or top section 6. The housing lower section 2 includes a portion as the lower porous hydrophobic membrane 4, and the housing upper section 6 includes a portion as the upper porous hydrophobic membrane 5. It should be understood that the upper and lower hydrophobic membranes can be a single hydrophobic membrane or a sheet of hydrophobic material extending between the lower section 2 and the upper section 6.

[0024] The housing 3 contains therein a mass, supply or quantity of a hygroscopic aqueous solution 8 for condensing water from the ambient air. A distillation process is used in the top section of the housing to extract water from the solution. The hygroscopic solution may be a lithium bromide solution or other suitable hygroscopic solution. The hygroscopic solution 8 absorbs water vapor 22 from the ambient air through the lower porous hydrophobic membrane 4 coupled to the lower section 2 of the housing. The hygroscopic membrane may be a porous Teflon TMOr hydrophobic porous polyvinylidene fluoride (PVDF). The properties of the hydrophobic porous membrane are such that the hygroscopic solution 8, which is an aqueous liquid, does not wet or travel through the pores of the hydrophobic membrane; however, gases (such as water in its gas phase) travel freely through the hydrophobic membrane. Therefore, the lower porous hydrophobic membrane 4 allows water vapor to enter the housing 3 from the environment, but does not allow liquid water to escape from the housing 3 in the opposite direction.

[0025] A heat source 21, which may be solar energy, electricity, gas, etc., is coupled to the housing upper section 6. The heat source 21 heats the housing upper section 6, so that the hygroscopic solution 8 contained in the housing upper section absorbs heat generated from the heat source 21.

[0026] The condensation chamber 10 is coupled to a thermal coupling 20, such as a heat sink fin. The thermal coupling 20 removes heat from the water 11 contained in the condensation chamber 10. The condensed water 11 in the condensation chamber 10 can be removed from the condensation chamber 10 through a drip tube 12.

[0027] By virtue of its hygroscopic properties, the now low-density hygroscopic solution 8 rises to the upper housing section 6 of the housing 3, where heat from the heat source 21 causes water to evaporate from the hygroscopic solution 8, thereby causing the water vapor to travel through the upper porous hydrophobic membrane 5 and into the condensation chamber 10. The condensation chamber outer wall 10A is maintained at a low temperature by a thermal coupling 20 to the surrounding ambient air to promote condensation of the water vapor within the condensation chamber 10. The resulting dense, water-depleted hygroscopic solution 8 migrates back to the lower housing section 2, where the hygroscopic solution 8 again reabsorbs water vapor through the lower porous hydrophobic membrane 4 as the process continues repeatedly.

[0028] Next reference Figure 1 , shows a representative example chart selected at random, which shows typical random variations of ambient temperature and relative humidity over a 30-day period. As can be seen from the chart, the typical variations are random in magnitude and are random relative to the time of day. In addition, temperature and humidity are random with respect to their highs and lows. For example, at event line 7 representing the 4th day, when the temperature is high at point 2 with a value of 28 degrees Celsius, the humidity is low at point 5 with a value of 35%, and when the temperature changes to low temperature at point 3 with a value of 14 degrees Celsius, the humidity changes to high humidity at point 6 with a value of 75%. On the other hand, at event line 9 on the 27th day, the humidity is high at point 16 with a value of 85%, and the temperature is high at point 11 with a value of 28 degrees Celsius, and when the temperature is low at point 13 with a value of 19 degrees Celsius, the humidity is also low at point 17 with a value of 40%. Both the relative direction and relative magnitude are random here.

[0029] For ease of explanation, event line 7 is assigned transition coordinates from (2,5) to (3,6), and event line 9 is assigned transition coordinates from (11,16) to (13,17). These transition coordinates are plotted on Figure 2 It shows the partial pressure of water vapor in the air as a function of relative humidity and temperature. Figure 1 The selected event lines or transitions 7 and 9 are indicated as transition coordinates (2,5) to (3,6) and transition coordinates (11,16) to (13,17), respectively. The temperature and humidity values ​​of these coordinates are taken from Figure 1 , as instructed. Figure 2 Used to further define coordinates by adding the partial pressure of water vapor in the air at selected temperature and relative humidity points. Within the approximate resolution of the graph, at coordinate (2,5) the partial pressure of water vapor in the air is 1.65 kPa, at coordinate (3,6) the partial pressure of water vapor in the air is 1.5 kPa, at coordinate (11,16) the partial pressure of water vapor in the air is 3.9 kPa, and at coordinate (13,17) the partial pressure of water vapor in the air is 1.2 kPa.

[0030] It is well known that certain salt solutions are naturally hygroscopic and have a water vapor pressure that varies depending on the temperature and the weight percentage mass of salt dissolved in the solution. These solutions maintain equilibrium water vapor pressure with their environment by absorbing or releasing water. Lithium bromide in water represents such a solution, and its tendency to attract and become more dilute in the presence of water vapor is the highest.

[0031] Figure 3 is a graph of the equilibrium water vapor pressure of an aqueous solution of lithium bromide as a function of temperature and the percent mass of lithium bromide in the solution. Selected example coordinates shown previously have been added to the graph to illustrate the effects of water vapor pressure on the water vapor pressure of an aqueous solution of lithium bromide upon exposure to Figure 1 The transformations that must occur in the solution of the instance coordinates or transformations selected in the example. Figure 3 In the example above, use Figure 2 The water vapor partial pressure values ​​are plotted against the corresponding temperature line to identify the mass percent lithium bromide concentration required for equilibrium. Figure 3 It can be seen that starting from the conditions at coordinates (2,5), the transition to coordinates (3,6) would require a drop in concentration from 44% to 31%. The water content starts at 56% and increases to 69%, an increase of 23%. The transition from coordinates (11,16) to (13,17) requires an increase in concentration from 18.5% to 29%. Here, the water content drops from 82% to 71%, a drop of 13%.

[0032] Next reference Figure 4 and 5 , showing that the change in enthalpy of the solution in these two examples is about 50 kJ / kg. Thus, a relatively small change in the net energy state of the solution is achieved after equilibrium of temperature and water vapor partial pressure. On the other hand, the energy for absorbing and evaporating water from a solution is significantly higher, about 2500 kJ / kg for condensation of water from a saturated vapor state to a liquid below 40 degrees Celsius, as given by Figure 5A exhibit.

[0033] Next reference Figures 6 to 8 , shows an ambient energy converter 40 in the form of the present invention. Here, the ambient energy converter 40 is configured to generate alternating current (AC) power as atmospheric temperature and humidity vary.

[0034] The ambient energy converter 40 has a housing 3 that holds a mass of a hygroscopic solution 8. The housing 3 includes a solution expansion (expansion surplus) chamber or reservoir (e.g., expansion surplus chamber 34) having a vent 38 or opening covered with a flexible diaphragm or breathable membrane. The cover 51 may be a breathable membrane, whereby the mass of hygroscopic solution 8 is contained within the housing, below the height or location of the vent 38 on the housing 3, so that air travels through the vent 38 and contacts the top surface of the hygroscopic solution 8. The excess volume 36 within the expansion surplus chamber 34 is provided to accommodate changes in the equilibrium level of the hygroscopic solution 8 within the ambient energy converter 40 as the temperature and humidity of the surrounding environment change. Alternatively, the cover 51 may be a flexible cover that expands convexly or concavely to accommodate changes in the volume of the hygroscopic solution 8.

[0035] The hygroscopic solution 8 in the housing 3 is in fluid communication with the surrounding air or environment through the ion or proton conductive highly waterproof membrane of the membrane electrode assembly 71. In one embodiment, the ion conductive membrane 64 is sandwiched between the electrodes 63 and 65. The combination of the ion conductive membrane 64 and the electrodes 63 and 65 forms the membrane electrode assembly 71. The membrane electrode assembly 71 is coupled to an external load / controller 60 having a connector 61, wherein the electricity generated by the membrane electrode assembly 71 powers the external load / controller 60. The membrane electrode assembly 71 allows water vapor 62 to pass through the membrane electrode assembly 71.

[0036] The operation is such that the hygroscopic solution 8 maintains temperature equilibrium with the surrounding air by heat transfer through the housing 3. The hygroscopic solution 8 maintains water vapor pressure equilibrium with the surrounding air by virtue of the water oxidation-reduction reaction through the membrane electrode assembly 71.

[0037] like Figure 76, during periods when the water partial pressure in the surrounding air is higher than the water pressure in the hygroscopic solution 8 (typically periods of high humidity), the pressure differential causes atmospheric water (water vapor) to be electrolyzed at the electrode 63, wherein the resulting protons are conducted through the ion-conductive membrane 64, the resulting oxygen 73 is released back to the surrounding air, and the resulting electrons are directed to the load / controller 60. The protons are conducted to the electrode 65, where they are reduced by the electrons flowing from the load / controller 60 and react with the dissolved oxygen 75 within the hygroscopic solution 8 to generate water within the hygroscopic solution 8. Thus, power is supplied to the load / controller 60 by the hygroscopic solution's attraction to the water vapor that drives the process. Ideally, the ion-conductive membrane 64 has high barrier properties and prevents water molecules from condensing directly and migrating into the hygroscopic solution 8. A thin ion-conductive barrier 70 is included to limit the molecular migration of water through the oxidation / reduction process so that the hygroscopic solution 8 absorbs water. The proton conducting membrane material (e.g., Nafion, manufactured and marketed by E.I. DuPont De Nemours and Company) is inherently hygroscopic and requires water as an essential component to facilitate ionic conduction. The thin ionic conducting barrier 70 prevents water from condensing directly into the conducting membrane and then migrating as molecules into the hygroscopic solution 8. The thin ionic conducting barrier layer 70 may be a hydrogen permeable material such as palladium or a polymeric water-repellent proton conducting material such as ceramic yttrium-doped barium zirconate YBaZrO 3 or titanium dioxide TiO 2 A high molecular weight waterproof ceramic proton material (such as TiO2) can be used exclusively as the ion conducting membrane 64 because it will have both the desired high barrier and proton conducting properties. Figure 7 The conveyed process is equivalent to an electrochemical redox process that is equivalent to condensing or actually or effectively condensing water into a solution under the water vapor pressure difference between the solution and the ambient air. Figure 8 Conveys a reverse electrochemical redox process equivalent to the evaporation or actual or effective evaporation of water from a solution at a water vapor pressure differential between the solution and the ambient air. Figure 8 , when the ambient water vapor pressure is lower than the water vapor pressure of the hygroscopic solution 8. Under this condition, the high water vapor pressure of the hygroscopic solution drives the oxidation of water at the electrode 65, where oxygen 75 is released back into the water. As the protons are conducted through the ion-conducting membrane 64, the electrons are directed to the load / controller 60 to the electrode 63, where the oxygen is released back into the hygroscopic solution 8. The protons conducted through the ion-conducting membrane 64 are reduced by the electrons from the load / controller 60 and react with oxygen from the outside air, where the resulting water is released to the environment.

[0038] The cell voltage is defined primarily through the condensation entropy of water:

[0039] ΔV=ΔS / 2F=2500j / (g2F)=0.233V.

[0040] It is reasonable to assume that the battery will experience water vapor absorption followed by evaporation on a daily basis (roughly over a 24 hour period). Figure 3 , 4 and 5 indicate an average water absorption / desorption of 15% of the mass of the solution per half-day cycle (0.15 g of water is absorbed and then desorbed per gram of solution per daily cycle). Table 1 presents an example half-day power generation transient. It provides an understanding of the power density obtainable from the present invention. 15% water absorption produces 1600 coulombs of electrons per gram, given as follows:

[0041] C = nAEm / MW.

[0042] Where n is the number of electrons involved in the process (2 per water molecule), A is Avogadro's number (6.02e23), E is the charge on a single electron (1.602e-19), and MW is the molecular weight of water, 18 g. The charge of 0.15 g of water per gram of solution per half cycle is:

[0043] I=2*6.03*10 23 *1.602*10 19 *0.15g / transient / g sol (1cm 3 *18 g / mole) = 1607.34 coulombs / g sol

[0044] Substituting these values ​​yields 1607 coulombs per gram. At 0.233 volts, for each gram of hygroscopic salt solution in the device, Figure 1 Given a representative daily temperature and humidity cycle presented in the figure, the average equivalent capacity is 104 mWh / g per half-day cycle. sol Or 208mWh / g per full day absorption and desorption cycle sol This is equivalent to 208Wh / kg, which is the capacity of a state-of-the-art lithium-ion battery cell.

[0045] Table 1

[0046] Volts = 0.233192 Coulomb = 1607.34 Ampere-hour = 0.446483 W.sec= 374.5102 Wh= 0.104031 Average 12-hour power = 0.008669

[0047] Next reference Fig. 9 , showing another preferred form of the environmental energy converter 79 of the present invention. Here, the environmental energy converter 79 is similar to Figure 6 , but also includes an air duct 84 around the lower part of the housing 3 containing the hygroscopic solution 8. The housing 3 also includes a porous hydrophobic membrane 80, which comprises a portion of the housing 3 opposite to the membrane electrode assembly 71.

[0048] The air flow 82 through the air conduit 84 can be facilitated by forced or natural convection. The air flow 82 enters the conduit 84 through the port 88 and first flows through the membrane electrode assembly 71, whereby water vapor is extracted from the air flow and absorbed into the hygroscopic solution 8, generating electricity and consuming oxygen from the hygroscopic solution 8 in the process. The now dry air flows through the porous hydrophobic membrane 80, whereby oxygen is freely absorbed into the hygroscopic solution 8 to replenish the oxygen consumed therefrom by the hydrogen entering the solution through the membrane electrode assembly 71. The air 82a, now depleted of moisture, then leaves the conduit 84 through the port 86. The hydrophobic membrane 80 and the air conduit 84 serve as a coupling mechanism to supply oxygen to the hygroscopic solution 8.

[0049] Other mechanisms will also be suitable, including oxygen injectors, bubblers, or solution spraying mechanisms. The device operates in reverse during conditions that promote evaporation of water from the hygroscopic solution as described above. As the air entering conduit 84 flows through the membrane electrode assembly 71 with water evaporating from the solution, the humidity level of the air will increase in humidity. Similarly, with the reduction of oxygen, additional oxygen will be released from the solution into the gas stream through the membrane 80 because the water is oxidized with the conduction of protons through the membrane electrode assembly 71.

[0050] Next reference Fig.10 , showing another preferred form of the environmental energy converter 83 of the present invention. Here, the environmental energy converter 83 is similar to Fig. 9 ; however, the expansion chamber 34 has a dropper coupled to the heat exchanger 92, which delivers water droplets 98 to the environment. The environmental energy converter 83 has an air conduit 84 surrounding the lower portion of the housing 3 containing the hygroscopic solution 8. The housing 3 also includes a porous hydrophobic membrane 80, which includes a portion of the housing 3 opposite the membrane electrode assembly 71. The air flow through the conduit 84 can be promoted by forced or natural convection. The air flow 82 enters the conduit 84 through the port 88 and first flows through the membrane electrode assembly 71, whereby water vapor is extracted and absorbed into the hygroscopic solution 8, generating electricity and consuming oxygen in the solution 8 in the process. The now dry air flows through the porous hydrophobic membrane 80, whereby oxygen is freely absorbed into the solution 8 to replenish the oxygen consumed therefrom by the hydrogen entering the solution through the membrane electrode assembly 71. The air 82a, which is now depleted of moisture, then leaves the conduit 84 through the port 86. The membrane 80 and conduit 84 serve as a coupling mechanism to supply oxygen to the hygroscopic solution. Other mechanisms would also be suitable, including oxygen injectors, bubblers, or solution spraying mechanisms. The additional heat source 102 supplies heat to continuously evaporate water from the hygroscopic solution 8 contained in the housing 3. The resulting water-depleted hygroscopic solution 8 migrates downward to the lower section of the housing 3 to reabsorb water, and thereafter rises back up so that a continuous water extraction process is maintained. This embodiment has the additional benefit of being a source for supplying fresh water. Although the power density per unit area of ​​the membrane electrode assembly 71 is due to impedance and O 2The activation energy is low, but the efficiency is extremely high.

[0051] Next reference Fig.11 , showing an ambient energy converter 85 in another preferred form of the present invention. Here, the ambient energy converter 85 includes a potential wet exhaust gas stream or flow (e.g., exhaust gas stream 90) that travels through a hot air exhaust pipe 101 or duct. The exhaust pipe 101 causes the exhaust gas stream 90 to travel through the interior of the air duct 84. Such an exhaust gas stream 90 can be supplied by high temperature exhaust gas from an internal combustion engine or other combustion process. It can also be exhaust gas from an evaporative cooling tower or other source. In the case where it is used in conjunction with the engine exhaust, the oxygen ion conductive membrane electrode assembly 100 is included to operate according to the oxygen partial pressure difference between the combustion exhaust gas depleted of oxygen and the ambient air. The power generated by the oxygen ion conductive membrane electrode assembly 100 when it conducts oxygen into the exhaust gas stream 90 under the oxygen partial pressure difference is supplied to the load / controller 60a.

[0052] Due to the oxygen pressure differential and the temperature of the converter, a voltage is generated across the membrane electrode assembly 71. The resulting power is supplied to the load / controller 60. The exhaust gas, now supplemented with oxygen, flows through the heat exchanger 93, where the heat of evaporation is transferred to the hygroscopic solution 8 to evaporate water therefrom. The resulting water vapor is coupled to the ambient air temperature through the heat exchanger 92, which causes it to condense, as illustrated by the water droplets 98. The now cooled exhaust gas stream 90 travels through the heat exchanger 95, where it is further cooled by thermal coupling with the ambient air before entering the conduit 84.

[0053] The wet potential exhaust stream 90 enters the conduit 84 and flows through the membrane electrode assembly 71, whereby water vapor is extracted and absorbed into the hygroscopic solution 8, generating electricity and consuming oxygen from the hygroscopic solution 8 in the process. Next, the now dry exhaust stream 90 flows through the porous hydrophobic membrane 80, whereby oxygen is freely absorbed into the hygroscopic solution 8 to replenish the oxygen consumed by the hydrogen entering the hygroscopic solution 8 through the membrane electrode assembly 71. The now cooled, moisture-depleted exhaust stream 96 then leaves the conduit 84 through the port 99. The membrane 80 and conduit 84 serve as a dry air coupling mechanism to supply oxygen to the hygroscopic solution. Other mechanisms will also be suitable, including oxygen injectors, bubblers, or solution spraying mechanisms. The heat exchanger 93 is used as a heat source in the expansion residual chamber 34 for evaporating water out of the solution 8.

[0054] If Fig.12 As shown, the electrochemical potential for oxidation of water to protons and oxygen ions is equal to the potential for reduction of protons and oxygen ions to water, 1.23 V. Due to the 0.4 V activation energy threshold for both oxidation and reduction reactions, the output current will be very dependent on the catalyst activity to approximate a reversible process resulting in a net power output. As the current draw increases, the impedance and activation voltage losses for oxidation and reduction of water deviate from the open circuit voltage of the cell. That is, the reference back Fig.11, at low currents, the condensation energy is converted to electricity for the water to go into solution, and will be almost equivalent to the evaporation energy input to the heat exchanger 93 to evaporate the water out of solution. In an ideal system, the heat input should be equal to the electricity generated.

[0055] It can thus be seen that there is now provided an ambient energy converter which overcomes the problems associated with prior art systems. Although the invention has been described in detail with particular reference to preferred embodiments thereof, it will be appreciated that many modifications, additions and deletions other than those explicitly described may be made thereto without departing from the spirit and scope of the invention.

Claims

1. An environmental energy converter, include: shell; a mass of hygroscopic solution contained within the housing, wherein the housing comprises a hydrophobic membrane in fluid communication with ambient air and the mass of hygroscopic solution; an ion-conducting membrane electrode assembly coupled to the housing and in fluid communication with the mass of hygroscopic solution and ambient air to facilitate an electrochemical redox process equivalent to condensing water onto and evaporating water from the mass of hygroscopic solution at a water vapor pressure differential between the mass of hygroscopic solution and the ambient air to generate electricity, and an air conduit positioned at least partially around the housing to direct airflow through the air conduit in fluid communication with the ion conductive membrane electrode assembly and the hydrophobic membrane, The hydrophobic membrane thereby allows oxygen to permeate between the mass of hygroscopic solution and the ambient air.

2. The ambient energy converter of claim 1, wherein the ion-conducting membrane electrode has a first electrode, a second electrode, and an ion-conducting component positioned between the first electrode and the second electrode, wherein the ion-conducting component is a proton-conducting component.

3. The ambient energy converter according to claim 1, wherein the ion-conducting component is a proton-conducting component having barrier properties to the diffusion of molecular water.

4. The ambient energy converter of claim 2, wherein the ion-conducting membrane electrode assembly further comprises an ion-conducting barrier mounted to the first electrode.

5. The ambient energy converter of claim 1, wherein the housing includes a drip tube extending from a top portion of the housing.

6. The ambient energy converter of claim 5, further comprising a heat exchanger thermally coupled to the drip tube.

7. The ambient energy converter of claim 1 further comprising a hot air tube running through the housing in thermal contact with the hygroscopic solution and through the air conduit.

8. The ambient energy converter of claim 7, further comprising an oxygen ion conducting membrane electrode assembly coupled to the hot air tube.

9. An environmental energy converter, include: an outer shell having a hydrophobic membrane portion; a mass of a hygroscopic solution contained within the housing and in fluid communication with the hydrophobic membrane portion; an ion-conducting membrane electrode assembly coupled to the housing between ambient air and the mass of hygroscopic solution to electrochemically generate electricity as water travels through the ion-conducting membrane electrode assembly at a water vapor pressure differential between the mass of hygroscopic solution and the ambient air, and An air conduit is positioned at least partially around the housing lower portion to direct air flow through the air conduit in fluid communication with the ion conductive membrane electrode assembly.

10. The ambient energy converter of claim 9, wherein the ion-conducting membrane electrode has a first electrode, a second electrode, and an ion-conducting component positioned between the first electrode and the second electrode.

11. The ambient energy converter of claim 10, wherein the ion conducting component is a proton conducting component.

12. The ambient energy converter of claim 10, wherein the ion-conducting membrane electrode is a barrier to molecular water migration.

13. The ambient energy converter of claim 9, further comprising an air conduit positioned at least partially around the housing lower portion to direct airflow through the air conduit in fluid communication with the ion conductive membrane electrode assembly and the hydrophobic membrane portion.

14. The ambient energy converter of claim 9, wherein the housing includes a drip tube extending from a top portion of the housing.

15. The ambient energy converter of claim 14, further comprising a heat exchanger thermally coupled to the drip tube.

16. The ambient energy converter of claim 13, further comprising a hot air tube running through the housing in thermal contact with the hygroscopic solution and through the air conduit.

17. The ambient energy converter of claim 16, further comprising an oxygen ion conducting membrane electrode assembly coupled to the hot air tube.

18. The ambient energy converter of claim 9, further comprising an expansion chamber for accommodating volume changes of the hygroscopic solution.

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