Patent ID: 12234749

DETAILED DESCRIPTION

Embodiments described herein are related to a hybrid heat engine system (e.g., a system to convert energy).

Systems are used to convert one type of energy to another type of energy. A system can convert thermal energy to mechanical energy. The thermal energy may be associated with a heat source and a heat sink. A system (e.g., heat engine) may bring a working fluid from a higher state temperature to a lower state temperature to convert thermal energy to mechanical energy to do mechanical work. A heat source may generate thermal energy that brings the working fluid to the high temperature state. The working fluid may generate work in the system (e.g., heat engine) while transferring heat to a heat sink until the working fluid reaches the low temperature state. Thermal energy may be converted into work by exploiting the properties of the working fluid. Increasing the temperature differential between the heat source and the heat sink increases the thermal efficiency of the system. The heat sink of heat engines is generally limited to being close to the ambient temperature of the environment, so most efforts to improve the thermal efficiency of heat engines focus on increasing the temperature of the heat source. Conventional heat engines use high-temperature heat sources and large temperature differentials between the heat source and the heat sink. The temperature of conventional heat engines are limited by the melting points of the materials that make up the heat engine, environmental concerns (e.g., limits on oxides of nitrogen (NOx) production, etc.), availability of high-temperature heat sources, etc. Conventional heat engines cannot efficiently extract energy from low-temperature heat sources. Conventional heat engines cannot efficiently extract energy from working fluid once the working fluid reaches a threshold temperature. This leads to wasted energy and a waste disposal problem.

Described herein are technologies of a hybrid heat engine system (e.g., a system to convert energy). In some embodiments, the system transforms a low-level temperature differential between a heat source and a heat sink into useful electrical power.

In some embodiments, the hybrid heat engine system is an energy-producing hydraulic ram system. A hydraulic ram system is a system that uses water hammer effect to raise a fluid at an original hydraulic head to a higher hydraulic head (e.g., this change in pressure can be used to convert energy and/or produce electricity).

In some embodiments, the hybrid heat engine system includes a valve, one or more first pipes, a chamber, and a piston. The valve is configured to provide a first fluid (e.g., gas, steam, etc.) from a heat source. The one or more pipes are fluidly coupled between the valve and a turbine. The one or more pipes house a second fluid (e.g., working fluid, water, fluid at a lower pressure than the steam from the heat source, etc.). The chamber is disposed between the valve and the one or more first pipes. The piston is disposed in the chamber between the first fluid and the second fluid. At least a portion of the second fluid is to be pushed through the turbine to generate energy responsive to actuation of the valve.

In some embodiments, a first distal end of the chamber is fluidly coupled to the heat source to receive the first fluid from the heat source responsive to actuation of the valve and a second distal end of the chamber is fluidly coupled to the one or more first pipes (e.g., one or more first pipes housing the second fluid) to receive a first amount of the second fluid. The piston is configured to move the first amount of the second fluid responsive to the actuation of the valve to increase pressure of the second fluid (e.g., cause water hammer in the second fluid) and to push at least a portion of the second fluid through the turbine.

In some embodiments, the hybrid heat engine system includes one or more second pipes fluidly coupled between the turbine and the one or more first pipes. The second fluid has a cyclical flow from the one or more first pipes to the turbine, from the turbine to the one or more second pipes, and from the one or more second pipes to the one or more first pipes. In some embodiments, the cyclical flow causes the second fluid to not be discarded or wasted (e.g., after the second fluid passes through the turbine).

In some embodiments, the hybrid heat engine system includes a condenser fluidly coupled to the heat source and the one or more first pipes. The condenser may be configured to condense at least a portion of the first fluid (e.g., expended fluid from the heat source used to push the working fluid) into a liquid to be combined with the second fluid in the one or more first pipes. The condenser may use second fluid from the heat sink as the cooling fluid.

In some embodiments, a hybrid heat engine system includes a hydro-electric turbine, a steam source configurable to generate steam from a hot water source, a condenser, and a slug intake bend (SIB) in a first pipe coupled between the steam source and the condenser. The SIB is configurable to receive a slug of water from a cold water source. The steam from the hot water source pushes the slug of water up a vertical distance to the condenser. The condenser is configurable to receive the slug of water and the steam, mix the slug of water with the steam to generate liquid water, and power a turbine with the liquid water.

By using low-level temperature differentials between a heat source and a heat sink, the systems (e.g., hybrid heat engine system, energy-producing hydraulic ram system, etc.) described herein can produce electrical power from low-temperature heat sources (e.g., waste liquid from mechanical processes) that were previously unused (e.g., at too low of a temperature to be used) by conventional systems. The systems described herein may use a heat engine that is not below ambient temperature (e.g., does not require lowering temperature of the heat sink below ambient temperature). The systems described herein may be made of materials with lower melting points than conventional systems (e.g., the low-temperature heat sources of the systems described herein can be used with materials with lower melting points than materials of conventional systems used with high-temperature heat sources). The systems described herein may have a better impact on the environment than conventional systems by extracting energy from low-temperature heat sources (e.g., waste water) whereas conventional systems generally dispose of the low-temperature heat sources (e.g., heating and providing waste to the environment).

The devices, systems, and methods disclosed herein have advantages over conventional solutions. The present disclosure has advantages of cost, efficiency, and adaptability when compared to conventional solutions. The present disclosure can be implemented under varying conditions. In some embodiments, the present disclosure can convert the thermal energy in water at temperatures at about 100 degrees Celsius to mechanical and electrical power. The present disclosure can be used in industries where low temperature waste heat is abundant and is currently underutilized. Such applications include mining, refining, and power generation industries.

Although some embodiments of the present disclosure refer to a system using steam and water, in some embodiments, other fluids can be used. For example, one or more types of gas (e.g., air, oxygen, steam, nitrogen, a refrigerant, exhaust gas, etc.) and/or liquids (e.g., water, a refrigerant, ammonia, waste water, waste liquid, etc.) can be used.

FIG.1Ais a schematic diagram illustrating a system100A to convert energy, according to certain embodiments. In some embodiments, system100A is a hybrid heat engine system that transforms a low-level temperature differential between a heat source and a heat sink into useful electrical power. In some embodiments, system100A is a hydraulic ram (hydram) system. In some embodiments, system100A is a hydram heat engine system. In some embodiments, system100A (e.g., hydram system, hydram heat engine system) uses a fluid piston through the hydraulic ram effect. The piston divides a chamber (e.g., cylinder) and is situated between a first distal end and second distal end of the chamber. When hot first fluid (e.g., water) is introduced at the first distal end of the chamber there is a small pressure differential between the first distal end and second distal end of the chamber. This pressure differential causes the piston to accelerate in the chamber from the first distal end to the second distal end of the chamber, gaining kinetic energy (KE) as it accelerates. As the piston reaches the second distal end of the chamber it is forced to decelerate rapidly. This rapid deceleration causes the KE of the piston to be transformed to a pressure surge in a second fluid on the second distal end of the chamber. This high-pressure second fluid is then passed through a high-pressure turbine, generating mechanical or electrical power (e.g., using hydraulic ram effect). In some embodiments, system100A uses the hydraulic ram effect to take advantage of efficiencies inherent to a high-pressure turbine compared to a low pressure turbine.

System100A may produce electric power from a lower temperature heat source. For example, system100A may combine characteristics of a steam engine and a power plant (e.g., hydropower plant) to economically produce electric power from a low temperature heat source.

System100A may be coupled to a heat source110and a heat sink120. In some embodiments, the heat source110may be configured to provide a fluid (e.g., gaseous fluid, steam, heated liquid) at higher-than-ambient temperature. The heat source110may be configured to generate steam from a hot water source. In some embodiments, the heat source110may harness waste (e.g., exhaust) or excess steam from a manufacturing or refining process. In some embodiments, the heat sink120is a cold reservoir216(e.g., cold reservoir216ofFIG.2). In some embodiments, heat sink120is a pool or reservoir of water. In some embodiments, heat sink120includes a pipe that houses fluid (e.g., spillway). In some embodiments, heat sink120includes a cooling tower or a set of cooling towers.

In some embodiments, system100A is coupled to a turbine140. In some embodiments, system100A includes turbine140. The turbine140may be a hydro-electric turbine. The turbine140may be a high-pressure turbine. System100A may include one or more valves150including a first valve151and/or a second valve152. The system100A may include one or more pipes160including a first pipe161, a second pipe162, and/or a third pipe163.

The heat source110may provide fluid (e.g., steam) to an input of the first valve151.

The first pipe161may be fluidly coupled between the heat source110and the turbine140(e.g., via the third pipe163). The second pipe162may be fluidly coupled between the turbine140and the first pipe161(e.g., fluidly coupled via the heat sink120, the second pipe162includes the heat sink120, etc.).

In some embodiments, a chamber is disposed between the first valve151and the first pipe161. In some embodiments, a piston (e.g., fluid piston, oil on water) is disposed in the chamber between a first fluid (e.g., steam) provided from the heat source110and a second fluid disposed in the first pipe161. In some embodiments, at least a portion of the second fluid is to be pushed through the turbine140to generate energy responsive to actuation of the first valve151(e.g., which causes the piston to move and cause water hammer and/or increased pressure in the second fluid in the first pipe161, system100A being a hydram system).

In some embodiments, a second valve152is coupled to the first pipe161and the heat sink120. The second valve152may be configured to allow a first amount of cold water (e.g., a slug of water) to flow from the cold water source (e.g., heat sink120) into the first pipe161. The first valve151may be controlled to provide fluid (e.g., steam) from the heat source110to push the slug of water (e.g., via a slug intake bend) through the turbine140to generate energy.

In some embodiments, a working fluid is pushed through one or more pipes (e.g., first pipe161and third pipe163) and through a turbine140to generate energy responsive to actuation of the first valve151. The working fluid may spin the turbine140to generate electrical power. Electrical power (ω T) may be the work of the turbine140over time (e.g., rate of the work of the turbine140).

FIG.1Bis a schematic diagram illustrating a system100B (e.g., system100A ofFIG.1A) to generate electrical power, according to one embodiment. System100B may be a heat engine that transforms a low-level temperature differential between a heat source and a heat sink into useful electrical power. System100B may be a hybrid heat engine. A hybrid heat engine may produce electric power from a lower temperature heat source, For example, a hybrid heat engine may combine characteristics of a steam engine and a power plant (e.g., hydropower plant) to economically produce electric power from a low temperature heat source.

System100B may be coupled to a heat source110and a cold water source (e.g., heat sink120). The heat source110may be configurable to generate steam from a hot water source. System100B may include a condenser130. In some embodiments, system100B is coupled to a turbine140. In some embodiments, system100B includes turbine140. The turbine140may be a hydro-electric turbine. The turbine140may be a high-pressure turbine. System100B may include valves150including a first valve151and a second valve152. The system100B may include pipes160including a first pipe161, a second pipe162, and a third pipe163. The first pipe161may include a slug intake bend (SIB)170. The system100B may include a water tower180.

The heat source110may be located at a first height. The heat source110may provide steam to an input of the first valve151.

In some embodiments, the condenser130is a jet condenser. In some embodiments, the condenser130is a surface condenser. In some embodiments, the condenser is an air-cooled condenser. For example, if the ambient temperature is very low (e.g., the condenser130is outside in the winter in a cold climate), an air condenser may be used. The condenser130may be disposed at a top end of a water tower180. The condenser130may have a water inlet132, a steam inlet134, and a water outlet136. The condenser130may be located at a second height that is at a higher elevation than the first height of the heat source110(e.g., steam source).

The first pipe161may be coupled between the heat source110and the water inlet132of the condenser130. The second pipe162may be coupled between a top portion of the first pipe161and the steam inlet134of the condenser130.

A second valve152may be coupled to the SIB170and the cold water source (e.g., heat sink120). The second valve152may be controlled to inject a first amount of cold water from the cold water source (e.g., heat sink120) into the SIB170. The first valve151may be controlled to inject the steam into the first pipe161. The steam may push the first amount of cold water as a slug of water through a vertical portion of the first pipe161upwards to the water inlet132of the condenser130. The vertical portion may correspond to the second height of the water tower180. The steam in the first pipe161may enter the second pipe162to be input into the steam inlet134of the condenser130.

The third pipe163may be coupled between the water outlet136of the condenser130and an input of the turbine140that is located at a lower elevation than the condenser130. The cold water received by the condenser130via the water inlet132and the steam received by the condenser130via the steam inlet134may mix in the condenser130. The cold water may condense the steam in the condenser130. The liquid water (e.g., cold water and steam that is condensed by the cold water) in the condenser130may flow (e.g., fall) through the third pipe163to the input of the turbine140responsive to being output from the water outlet136of the condenser130. The third pipe163may be a vertical pipe coupled to a bottom of the condenser130and a top portion of the turbine140. The liquid water may spin the turbine140to generate electrical power. Electrical power (ω T) may be the work of the turbine140over time (e.g., rate of the work of the turbine140).

FIG.2is a schematic diagram illustrating a system200(e.g., system100A ofFIG.1A, system100B ofFIG.1B) to generate electrical power, according another embodiment. Elements inFIG.2that have a similar reference number as elements inFIG.1Aand/orFIG.1Bmay include similar features and similar functionality as the elements described in relation toFIG.1Aand/orFIG.1B. System200may be a heat engine that transforms a low-level temperature differential between a heat source and a heat sink into useful electrical power. System200may be a hybrid heat engine. A hybrid heat engine may produce electric power from a lower temperature heat source, For example, a hybrid heat engine may combine characteristics of a steam engine and a power plant (e.g., hydropower plant) to economically produce electric power from a low temperature heat source.

System200may be coupled to a hot reservoir212(e.g., a steam source, heat source110, etc.), a disposal sink214, and a cold reservoir216. System200may include or may be coupled to a drum222and a pump224. System200may include an air pump226(e.g., vacuum pump) and control box228. System200may include one or more of a first valve151, a second valve152, a third valve153, a fourth valve154, or a fifth valve155. System200may include one or more of a first pipe161, a second pipe162, a third pipe163, a fourth pipe164, or a fifth pipe165.

System200may be a heat engine that is coupled to a heat source and a heat sink. The heat engine may include a working fluid and may generate electrical power.

The heat sink may be the cold reservoir216(e.g., cold water source (e.g., heat sink120), reservoir of cold water). The cold reservoir216may be located at a base of the turbine140. The cold reservoir216may be a large reservoir of water that is cooled by direct exposure to the atmosphere and other surroundings. Cooling water and condensate from the turbine140may pass (e.g., be output) to the cold reservoir216(e.g., after use) where the cooling water and condensate is cooled to the temperature of the cold reservoir216by convection and evaporation. In one embodiment, the cold reservoir216is a natural body of water (e.g., lake, pond, ocean, river, stream, etc.) that is exposed to the atmosphere. In another embodiment, the cold reservoir216is a man-made body of water (e.g., a cooling pond, etc.) that is exposed to the atmosphere. In another embodiment, the cold reservoir216may include a liquid that is not water. For example, the cold reservoir216may include a refrigerant (e.g., ammonia). The cold reservoir216may include water with gas dissolved in the water at pressure (e.g., Patm) higher than the pressure of the condenser (e.g., Pcondenser). The water in the cold reservoir216may or may not be in a saturated state, but the non-condensable gases may remain dissolved until the pressure is reduced below a threshold pressure.

In one embodiment, the working fluid is water. In another embodiment, the working fluid is a refrigerant. For example, the working fluid may be ammonia. The working fluid may include gas (e.g., non-condensable gases) dissolved in the working fluid at the original pressure of the working fluid (e.g., Patm). As the pressure is reduced below the original pressure (e.g., reduced towards Pcondenser), the gas (e.g., non-condensable gases) may bubble out of the working fluid. The working fluid may be extracted from the cold reservoir216and expelled to the cold reservoir216(e.g., the working fluid and the fluid in the cold reservoir216may be the same fluid).

The heat source may be the hot reservoir212. The hot reservoir212may be part of the heat source110(e.g., steam source). In one embodiment, the hot reservoir212includes waste water that is at a higher temperature than the cold reservoir216. In one example, the waste water is from a processing plant. In another example, the waste water is from an oil refinery. In another embodiment, the hot reservoir212includes co-produced water from an oil platform (e.g., offshore platform, oil rig). In another example, the hot reservoir212includes cooling water that has been heated by a power plant. In another embodiment, the hot reservoir212includes exhaust from a power plant. In another embodiment, the hot reservoir212includes brackish water.

In one embodiment, a power plant may use multiple stages to extract energy from a working fluid or exhaust. The power plant may use system200to extract energy from a working fluid or exhaust subsequent to a first system extracting energy from the working fluid or exhaust. For example, a power plant (e.g., combined cycle power plant) may use a reciprocating engine to generate electrical power from working fluid or exhaust, may then use the exhaust output from the reciprocating engine to run a steam turbine to generate energy, and then may use system200to extract more energy from the exhaust output from a heat exchanger that heats the working fluid that goes into the steam turbine. By using system200, a power plant may achieve higher efficiency and waste less energy.

In one embodiment, the hot reservoir212may be at a lower elevation (e.g., at the bottom of a hill or mountain) and the liquid water from the condenser130is at a higher elevation (e.g., at the top of a hill or mountain) than the hot reservoir212. The liquid water may be at least a threshold distance below the condenser (e.g., 10 meters (m)). The turbine140may be at a lower elevation than the liquid water. The liquid water from the condenser130may be stored at the higher elevation and may be allowed to flow down to the turbine140at the lower elevation to generate electrical power.

The water in the hot reservoir212may be at a first temperature (TH) and a saturation pressure (PH,sat) or atmospheric pressure (Patm). In some embodiments, the pump224may pump water from the hot reservoir212into the drum222and may increase the pressure of the water to a pressure (PH) that is above PH,sat(at the beginning of each cycle). In some embodiments, hot water at a pressure (PH) higher than PH,satis being provided to the drum222(at the beginning of each cycle). The drum222may throttle the water to a pressure (Pdrum) that is lower than PH,sat. By throttling the water to Pdrum, some of the liquid water changes to steam to expand up the pipe. Water in the cold reservoir216may be at atmospheric pressure (Patm) and at a second temperature (TC) that is less than TH(e.g., TC=30 degrees Celsius (° C.) and TH=100° C.).

The air pump226(e.g., a vacuum pump) may pump air (e.g., non-condensable gases) out of the condenser130to maintain the condenser130at a pressure (Pcondenser) that is less than Patm. The condenser130, SIB170, and first pipe161may all be at Pcondenser. The air pump226may create a vacuum in the first pipe161(e.g., to suction cold water from the cold water source (e.g., heat sink120) to the SIB170, etc.). The air pump226may expel the non-condensable gases in the condenser130to the atmosphere (e.g., by bringing the non-condensable gases to a pressure exceeding atmospheric pressure). Non-condensable gases may include hydrogen sulfide, methane, etc. In some embodiments, the non-condensable gases are filtered as they are expelled from the condenser130. In some embodiments, the non-condensable gases are discarded after being expelled from the condenser130. In some embodiments, the non-condensable gases are burned after being expelled from the condenser130. The burning of the non-condensable gases may be used to provide extra heat. For example, the extra heat can be used for heating the hot reservoir212.

The heat source110(e.g., steam source) may include a drum222, a pump224, a third valve153, and a fifth valve155. The heat source110(e.g., steam source) may be coupled to a hot reservoir212and a disposal sink214.

Hot water may be at THand PH,sat(e.g., 212 degrees Fahrenheit (° F.) and 1 atmosphere (atm)) in the hot reservoir212. A first amount of the hot water may be pumped by pump224from the hot reservoir into the drum222(with the third valve153open, the first valve151closed, and the fifth valve155closed). The first amount of the hot water may be pumped into the drum222at PH, where PHis greater than PH,sat. (e.g., PH,satis 1 atm and PHis greater than 1 atm). Responsive to the first amount of hot water entering the drum222, the third valve153may close. The hot water in the drum222is pressurized (at PH,sat). The drum222may throttle the water to a pressure (Pdrum) that is lower than PH,sat. By throttling the water to Pdrum, some of the liquid water changes to steam to expand up the first pipe161. The first valve151may be opened and steam from the first amount of hot water in the drum222may expand into first pipe161. The steam may decrease from Pdrumtowards Pcondenserby expanding against a slug of water through first pipe161. The viscosity of the water may hold the slug of water together as it is pushed by the steam. The pressure (PH) of the steam and the amount of hot water in the drum222may be sufficient to push a first slug of water from the SIB170of the first pipe161into the condenser130. A second slug of water may enter the SIB170(e.g., after the steam pushes the first slug into the condenser130or before the steam pushes the first slug into the condenser130as long as the first slug has the kinetic energy to enter the condenser). The second slug of water may be pushed by a second amount of steam and the second slug of water may push the previous amount of steam into the condenser130.

The condenser130may mix the slug of water with the steam to generate a mixture (e.g., a saturated mixture). The steam, slug of water, and air pump226may maintain the condenser130at a constant pressure (Pcondenser) and temperature (Tcondenser). Tcondensermay be higher than TCand lower than TH.

The fourth valve154may remain closed while the air pump226initially sets the pressure of the condenser130to Pcondenser. The fourth valve154may also remain closed to store energy in the condenser130. The fourth valve154may be opened to allow the liquid water from the condenser130to flow (e.g., fall) through the third pipe163to the turbine140to spin the turbine to generate electrical power. The liquid water may exit the turbine140to the cold reservoir216. The liquid water from the turbine140may be at Tcondenserthat is higher than TCof the cold reservoir216. The liquid water at Tcondensermay mix with the water in the cold reservoir216(to meet equilibrium) and the cold reservoir216may maintain TCvia convection and evaporation.

The drum222may be a throttling drum. The drum222may throttle the water to a pressure (Pdrum) that is lower than PH,sat. In some implementations, the drum is elevated at a height (H1) similar to the height of the SIB. The height H1may be such that the steam outlet of the drum222may be as close as possible to the slug bottom face (e.g., H1may be substantially similar to or the same as the height H6of SIB170). The drum222may be connected to the heat source (e.g., hot reservoir212) by a fourth pipe164and a third valve153. The third valve153may be a throttling valve.

The drum222may be connected to a disposal sink214that is vertically below the drum222by a fifth pipe165and a fifth valve155. The disposal sink214may be located below the drum222. The disposal sink214may be situated far enough below the drum222(vertical height H2) such that water easily drains out of the drum222. The fifth valve155may be controlled to remove liquid water from the drum222(e.g., at the end of the cycle).

In some embodiments, the water may be drained out of the drum222when the drum222is at the pressure of the condenser130(Pcondenser) and/or the temperature of the condenser (Tcondenser). For example, the liquid in the drum222may be initially at 100° C. and the liquid may be drained once the liquid is proximate to 30° C. In some embodiments, the liquid may be drained out of the drum222at the end of each cycle.

In some embodiments, the liquid may be drained out of the drum when the liquid is at a pressure and/or temperature that are lower than THand PH, but higher than Tcondenserand Pcondenser. For example, the liquid in the drum222may be initially at 100° C. and the liquid may be drained once the liquid is proximate to 60° C. when Tcondenseris at 30° C.

In some embodiments, there is a constant flow of hot water from the hot reservoir212into the drum222by flowing the hot water at a constant rate into the drum222and flowing steam and remaining hot water out of the drum222. The drum222may be a drum or a throttling valve to adjust the pressure (e.g., reduce the pressure) of the steam to push the slug of water up the first pipe161into the condenser130. The first valve151may close while the slug of water is being siphoned into the SIB170from the cold reservoir216. The control box228may control first valve151, second valve152, third valve153, and fifth valve155to provide the amount of water in each slug and the pressure of steam to be able to push each slug into the condenser130.

The drum222may be connected to the SIB170by first pipe161and a first valve151in the first pipe161. The first valve151may be located at the top of the drum222.

The drum222may be fueled by injections of hot water from hot reservoir212(e.g., a reservoir of hot water). The drum222may be configured to maintain PHand to throttle the water from PHto a pressure (Pdrum) that is lower than PH,sat. By throttling the water to Pdrum, some of the liquid water changes to steam to expand up the pipe. The condenser130may be configured to maintain Pcondensercorresponding to a saturation pressure of the cold water from the slug mixed with condensate. Pcondensermay be lower than Pdrum. The steam from the drum, when allowed by the first valve151, may expand against the Pcondenserat the condenser130, pushing the slug up the first pipe161and into the condenser130. The water from the slug may be mixed with the steam coming into the condenser130, cooling and condensing the steam and maintaining Pcondenserof the condenser130.

The SIB170may be a U-shaped bend in the first pipe161adjacent to and just above the drum222. Cold water may be injected to the SIB170from a cold water source (e.g., the heat sink, the cold reservoir216). The timing and amount of this injection may be controlled by second valve152. Timing and duration of the second valve152may be controlled to inject the first amount of water into the SIB170without a pump. In some embodiments, at the time of the injection, the SIB170may be at a lower pressure (Pcondenser) than the heat sink (e.g., Patmof cold reservoir216) and the water may be sucked into the SIB170when the valve is opened without the need for a pump. In some embodiments (the first cycle), air pump226provides the pressure difference (maintains Pcondenserbelow Patm) to siphon the cold water from the cold reservoir216. The height (H6) of the SIB may be slightly less than the pressure differential in head that exists between the atmosphere and the condenser130. The height H6may be the maximum height possible so that a difference between Pcondenserand Patmof the cold water source (e.g., cold reservoir216) is sufficient to propel the cold water into the SIB170without mechanical assistance (e.g., such that water is quickly and easily sucked into the SIB170at the time of injection when the pressure in the SIB170is equal to that of the condenser130).

The condenser130may be a jet condenser. The condenser may include a top compartment and a bottom compartment. Liquid water from the slug may come into direct contact with the steam coming behind it. The cold water from the slug may enter (e.g., fall) into a top compartment in the condenser where the condenser may spray a mist of water from the slug of water into the bottom compartment. The steam behind the slug may be routed via steam inlet134to the bottom compartment in the condenser130by a second pipe162, where the steam rises to meet the liquid water mist and condenses. The bottom of the condenser may be coupled to a third pipe163that extends to a turbine through which liquid water (e.g., the slug water and condensate) flow (e.g., fall) to enter the turbine140. The liquid water may spin the turbine140to generate electric power. The height (H5) of the condenser130may be great enough so that the pressure of a column of water of height H5is greater than the difference in pressure between the cold reservoir216and the condenser130. This difference in pressure between the condenser and a pressure in head having the value H5may determine the maximum possible pressure at which the turbine may be operated.

The turbine140may be located below the condenser130and may be connected to the condenser by a vertical third pipe163. The third pipe163may be termed a water tower180which as a height of H5. Condensate and cooling water run down the water tower180(e.g., third pipe163) and enter the turbine140at an absolute pressure in head equal to the height of the water tower180. The falling water may spin the turbine140to generate electrical power.

The system200may include a control box228. The control box228may regulate the timing of valves of the system and control the amount of water injected into the drum222and into the SIB170. The control box228may determine the amount of water injected based on variables including temperatures of the hot reservoir212and the cold reservoir216and power generation needs of the operators.

The control box228may include a processing device to execute operations. The processing device may include one or more of a processor, a microprocessor, a controller, a microcontroller, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), network processor or the like. The operations may include one or more of blocks502-514ofFIG.5. The processing device of the control box228may execute a control algorithm to determine the first amount of cold water to be injected into the SIB170and the first amount of hot water to be injected into the drum222, respectively, based on variables comprising at least one of a temperature of the steam source, a temperature of the cold water source, a temperature of atmosphere, and a specified power generation requirement.

As shown inFIG.2, the turbine140, the heat source110(e.g., steam source), and the SIB170may be above ground level. The condenser130is located at a height above the turbine140, the heat source110(e.g., steam source), and the SIB170. The liquid water may flow (e.g., fall) from the condenser130down the height through a pipe (e.g., third pipe163) and enter the turbine140to spin the turbine140to generate electrical power.

FIG.3is a schematic diagram illustrating a system300(e.g., system100A ofFIG.1A, system100B ofFIG.1B, system200ofFIG.2) to generate electrical power, according another embodiment. Elements inFIG.3that have a similar reference number as elements inFIG.2,FIG.1A, and/orFIG.1Bmay include similar features and similar functionality. System300may be a heat engine that transforms a low-level temperature differential between a heat source and a heat sink into useful electrical power. System300may be a hybrid heat engine. A hybrid heat engine may produce electric power from a lower temperature heat source, For example, a hybrid heat engine may combine characteristics of a steam engine and a power plant (e.g., hydropower plant) to economically produce electric power from a low temperature heat source.

As shown inFIG.3, the turbine140and the heat source110(e.g., steam source) are below ground level. The condenser130is located above ground level. The condenser130may be located at a height above the turbine140. The liquid water may flow from the condenser130down the height through a pipe and enter the turbine to spin the turbine140to generate electrical power.

As shown inFIG.3, the hot reservoir212is located above the drum222. The hot water from the hot reservoir212may flow to and pressurize the hot water in the drum222without the use of a pump (e.g., pump224). As shown inFIG.3, since the turbine140is located below ground level, the condenser130may not be located on a water tower180or the water tower180may be shorter than the water towers180ofFIGS.1-2.

The control box228opens third valve153to insert a first amount of hot water in the drum222from the hot reservoir212via fourth pipe164. The first amount of hot water in the drum is at PHwhich is greater than PH,satof the hot water in the hot reservoir212. The drum222may throttle the water to a pressure (Pdrum) that is at PH,sat, or a lower pressure. The SIB170is at Pcondenserthat is less than PCof the second cold reservoir216b. The second cold reservoir216bmay be a tank under the turbine140. The second cold reservoir216bmay be smaller than the first cold reservoir216a.

In some embodiments, the control box228opens second valve152to siphon a first amount of cold water from the second cold reservoir216blocated below turbine140. In some embodiments, the control box228opens second valve152to siphon a first amount of cold water from the turbine140. The first amount of cold water may be siphoned because of the difference in pressure between Pcondenserand PC. The control box228opens first valve151to allow the first amount of hot water at Pdrumin the drum222which is greater than Pcondenserto expand and to push the slug of water (the first amount of cold water in the SIB170) up the first pipe161and to the condenser130. The slug of water enters the condenser130via water inlet132, the steam enters the condenser via steam inlet134, and the slug and steam mix (e.g., the steam condenses). Liquid water from the condenser130flows through third pipe to one or more of first cold reservoir216aor to the turbine140. The liquid water from the condenser130may be stored in the first cold reservoir216ato store energy for later use. In some embodiments, the fourth valve154is disposed between the turbine and the first cold reservoir216a, proximate first cold reservoir216a. In some embodiments, a sixth valve156is disposed between the condenser130and the first cold reservoir216a.

The control box228may open the fifth valve155for the liquid in the drum222to flow to the disposal sink214. In some embodiments, the liquid in the disposal sink is pumped to ground level to be disposed. In some embodiments, the disposal sink is below the water table and the liquid in the disposal sink214percolates into the ground.

In some embodiments, the components of system300that are below ground level may be in a well (e.g., a shaft that extends into the ground). For example, the components below ground level may be in an oil well (e.g., a used oil well).

In one embodiment, the heat engine in system200ofFIG.2and/or the heat engine in system300ofFIG.3are part of a first heat engine cycle including states 1a-5a. From state 1a to state 2a, hot water from the hot reservoir212may be pressurized to a pressure (PH) greater than the saturation pressure (PH,sat) of hot water. The pressurized hot water may be injected into the drum222and sealed therein. The drum222may throttle the water to a pressure (Pdrum) that is lower than PH,sat.

From state 2a to state 3a, the first valve151between the drum222and the first pipe161opens. Hot steam leaves the drum under pressure (Pdrum) and pushes against the slug in the SIB170, pushing the slug up the first pipe161into the condenser130. As the steam from the drum expands, the saturated mixture cools until it is the temperature (Tcondenser) of the condenser130as the last of the slug spills into the condenser130. The fifth valve155between the drum222and the disposal sink214opens and the now cold liquid water (e.g., colder than TH) in the drum222is expelled to the disposal sink.

From state 3a to state 4a, the steam, now at the saturation temperature and pressure of the condenser130, is pushed into the condenser130by a succeeding slug. In the condenser130, the steam mixes with the atomized liquid water from the slug the steam had pushed and the steam is condensed to liquid water. Non-condensable gases are pumped out of the condenser by an electric pump (e.g., air pump226).

From state 4a to state 5a, the slug water and condensate fall down the water tower180(third pipe163) and run through a turbine140, generating electric power. The liquid water is then expelled from the turbine140to the cold reservoir216.

From state 5a to state 1a, the slug water and condensate are cooled to the temperature of the cold reservoir by convection with the surroundings and by evaporation. The cold water is then sucked up into the SIB170and the cycle is complete.

In another embodiment, the heat engine in system200ofFIG.2and/or the heat engine in system300ofFIG.3are part of a second heat engine cycle including states 1b-5b. The second heat engine cycle may maintain steady state (e.g., constant pressure and constant temperature) in the drum222which may simplify the system. The second heat engine cycle may have a greater energy output than the first heat engine cycle over time, but may be less efficient than the first heat engine cycle.

From state 1b to state 2b, hot water from the hot reservoir212is pressurized to a pressure (PH) greater than the saturation pressure (PH,sat) of the hot water and is injected into the drum222where the hot water is throttled to a pressure (Pdrum) less than the saturation pressure of the hot water in the hot reservoir212. By throttling to Pdrum, some of the liquid water changes to steam and then can expand up the pipe, pushing the slug.

From state 2b to state 3b, hot steam leaves the drum222at constant pressure and pushes against the slug in the SIB170, pushing the slug up the pipe161into the condenser130. A constant pressure and temperature is maintained in the drum222by regulating the flow of hot water into the drum222and the flow of liquid water out of the drum222to the disposal sink214. Once the slug has sufficient kinetic energy to make it to the condenser130without assistance from the force of the hot steam beneath it, a new slug is sucked into the SIB170.

From state 3b to state 4b, in the condenser130, the steam mixes with the atomized liquid water from the slug that the steam had pushed and the steam is condensed to liquid water. Non-condensable gases are pumped out of the condenser by an electric pump (air pump226).

From state 4b to state 5b, liquid water (e.g., the slug of water and condensate) fall down the water tower180and run through a turbine140, generating electric power. The liquid water is then expelled to the cold reservoir216.

From state 5b to state 1b, the slug water and condensate are cooled to the temperature of the cold reservoir216by convection with the surroundings and by evaporation. The cold water is then sucked up into the SIB170and the cycle is complete.

In some embodiments, the system200ofFIG.2and/or the system300ofFIG.3has an alternative heat engine design. In the alternative heat engine design, H1may be such that pressure head of H1is equal to atmospheric pressure (Patm) minus the pressure in the condenser130(Pcondenser) (hH1=Patm−Pcondenser). In the alternative engine design, H2may be such that the pressure head of H2is equal to atmospheric pressure (Patm) minus the pressure in the drum222(PH) (hH2=Patm−Pdrum). In the alternative heat engine design, H3times acceleration of gravity times mass flow rate of the slug up the tower is the work rate done by the system. In the alternative heat engine design, H5times acceleration of gravity times mass flow rate of water from the condenser130to the turbine140is the output work rate of the system. In the alternative heat engine design, H6may be such that pressure head of H6is less than atmospheric pressure (Patm) minus the pressure in the first pipe161at the slug intake (Ppipe) (hH6<Patm−Ppipe). How much less depends on the pressure differential needed to upload the slug. The pressure differential may be minimized to maximize output work. In the alternative heat engine design, H7(height of condenser130) may be sufficient height so that the cold water from the slug runs through the condenser130. The condenser130height H7may be minimized to maximize output work.

FIG.4is a flow diagram of one embodiment of a method400of generating electrical power, in accordance with embodiments of the present disclosure. The method400may be performed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (e.g., instructions run on a processor to perform hardware simulation), or a combination thereof. In one embodiment, the method400may be performed by system100A ofFIG.1Aand/or system100B ofFIG.1B. In one embodiment, the method400may be performed by system200or control box228ofFIG.2. In one embodiment, the method400may be performed by system300or control box228ofFIG.3. In one embodiment, the method400may be performed by a processing device of a control box228of a heat engine. Alternatively, the method400can be performed by other components as described herein.

Referring toFIG.4, at block402, the control box228implementing the method may control the pump224and the third valve153to inject hot water into the throttling drum222at a beginning of a cycle.

At block404, the control box228may control a second valve152to inject a first amount of cold water from a cold water source (e.g., heat sink120) into a SIB170of a first pipe161coupled between a heat source110(e.g., steam source) and a water inlet132of a condenser130. In some embodiments, the control box228may control the air pump226in conjunction with the second valve152to inject the first amount of cold water from the cold water source (e.g., heat sink120) into the SIB170.

At block406, the control box228may control a first valve151to inject a first amount of steam, fueled by a hot water source (e.g., of a hot reservoir212), from the drum222into the first pipe161to push the first amount of cold water as a slug of water through a vertical portion of the first pipe161upwards to the water inlet132of the condenser130. The first amount of steam may enter a steam inlet134of the condenser130.

At block408, the control box may control the air pump226to remove non-condensable gases from the condenser130.

At block410, the control box may control a fourth valve154to allow liquid water from a water outlet136of the condenser130to flow (e.g., fall) through a third pipe163to an input of turbine140(e.g., a hydro-electric turbine). The liquid water may spin the turbine140to generate electrical power.

At block412, the control box may control the fifth valve155to remove water (e.g., liquid water) from the drum222at an end of the cycle.

FIG.5Ais a flow diagram of one embodiment of a method500of computing values to control a mechanical system to generate electrical power, in accordance with embodiments of the present disclosure. The method500may be performed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (e.g., instructions run on a processor to perform hardware simulation), or a combination thereof. In one embodiment, the method500may be performed by system100A ofFIG.1Aand/or system100B ofFIG.1B. In one embodiment, the method500may be performed by system200or control box228ofFIG.2. In one embodiment, the method500may be performed by system300or control box228ofFIG.3. In one embodiment, the method500may be performed by a processing device of a control box228of a heat engine. Alternatively, the method500can be performed by other components as described herein.

Referring toFIG.5A, at block502, the control box228implementing the method550may determine the first amount of cold water to be injected into the SIB170by the second valve152. The first amount of cold water may be based on variables comprising at least one of a temperature of the heat source110(e.g., steam source), a temperature of the cold water source (e.g., heat sink120), a temperature of atmosphere, and a specified power generation requirement.

At block504, the control box228may determine a first timing of an injection of the first amount of cold water into the SIB170by the second valve152. The timing may be after the condenser130is at a pressure (Pcondenser) that is less than the pressure (Patm) of the cold reservoir216. The control box228may control the air pump226to set the pressure of the condenser130to Pcondenser.

At block506, the control box228may determine a second amount of hot water to be injected into the drum222by the third valve153. The first amount of hot water may be based on variables comprising at least one of a temperature of the heat source110(e.g., steam source), a temperature of the cold water source (e.g., heat sink120), a temperature of atmosphere, and a specified power generation requirement.

At block508, the control box228may determine a second timing of an injection of a first amount of steam into the first pipe161by the first valve151.

At block510, the control box228may determine the third amount of liquid water to be allowed to flow from the water outlet136of the condenser130through the third pipe163to an input of a turbine140by the fourth valve154.

At block512, the control box228may determine a third timing of allowing of the third amount of liquid water to flow from the water outlet136of the condenser130to the input of the turbine140by the fourth valve154.

At block514, the control box228may determine a fourth timing for ejecting water from the drum222by the fifth valve155.

FIG.5Bis a flow diagram of one embodiment of a method550of computing values to control a mechanical system to generate electrical power, in accordance with embodiments of the present disclosure. The method550may be performed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (e.g., instructions run on a processor to perform hardware simulation), or a combination thereof. In one embodiment, the method550may be performed by system100A ofFIG.1Aand/or system100B ofFIG.1B. In one embodiment, the method550may be performed by system200or control box228ofFIG.2. In one embodiment, the method550may be performed by system300or control box228ofFIG.3. In one embodiment, the method550may be performed by a processing device of a control box228of a heat engine. Alternatively, the method550can be performed by other components as described herein.

Method550may enable the control box228to optimize the variables for efficiency, power, and cost. The control box228implementing the method550may determine, in real time, the optimal amount (e.g., mass) of cold water to be injected into the SIB170per cycle and the optimal amount (e.g., mass) of hot water to be injected into the drum222per cycle. The method550may use successive substitution approach to simultaneously solve equations (1) through (10). Equations (1)-(10) and the corresponding variables are shown below.

Referring toFIG.5B, at block552, the control box228implementing the method550may set k to zero and M0to one (k=0 and M0=1).

At block554, the control box228may calculate (e.g., using an initial value problem (IVP) solver) M(τ) using equation (1) with no heat loss. Equation (1):
M′(τ)=(E(τ,M))/(F(τ,M)),TC≤τ≤TH, M(TH)=M0
E(τ,M)=M*δ′(τ)−M0*u′g(τ)+[(k*X(τ,M)*(τ−Tatm))/(A*v(X(τ,M)))+P(τ)]*R(τ)*(M0−M)
F(τ,M)=−δ(τ)−[(k*X(τ,M)*(τ−Tatm))/(A*v(X(τ,M)))+P(τ)]*S(τ)
δ(τ)=ug(τ)−uf(τ)
R(τ)=(ρ′st(τ))/(ρst2(τ))−(ρ′w(τ))/(ρw(τ))
S(τ)=(ρw(τ)−ρst(τ))/(ρst(τ)*ρw(τ))  (1)

At block556, the control box228may calculate K using the following equation: K=M(TC).

At block558, the control box228may calculate M0using equation (2). Equation (2) is an initial guess of M0(the mass of water injected in the drum222):
M0=ρst(TC)*vmax/(1−K)  (2)

At block560, the control box228may set k=0 and use the initial guess of M0from block558, to again compute M(τ) using equation (1) (e.g., using an IVP solver) with no heat loss.

At block562, the control box228may determine whether M(TC) minus the old M(TC) is greater than epsilon (a small number that represents the tolerance for error in the results of the method550; as long as the estimated error is greater than a user-defined epsilon, the method will be iterated to provide better results) using the following equation:
M(TC)−old M(TC)>ε

In response to M(TC) minus old M(TC) being greater than epsilon, flow continues to block564. In response to M(TC) minus old M(TC) not being greater than epsilon, flow continues to block578.

At block564, the control box228may calculate X(τ, M) using equation (3) and calculate T(x) using equation (4). Equation (3) is used to determine the position of the bottom edge of the slug up the first pipe161(at temperature τ and mass M):
X(τ,M)=(M0−M)*S(τ)/A(3)

The variables M0and M may be recalibrated to make up for the volume in the drum222that will be occupied by steam as the liquid water changes to steam. This may be calculated using a bisection method to find the correct value of M0such that X(TC)=H and recalculating M with no heat loss (using the IVP solver on each iteration).

The variable X(T) may be redefined with the revised M(τ) function using equation (3). Equation (4) may provide the temperature of the saturated mixture below the slug when the slug is at position “x.” Equation (4) is a temperature at position x:
T(x)=inverse ofX(τ)  (4)

At block566, the control box228may set a=H and va=0.

At block568, the control box228may determine whether a minus old a is greater than epsilon with the following equation: a−old a>ε

In response to a minus old a being greater than epsilon, flow continues to block570. In response to a minus old a not being greater than epsilon, flow continues to block574.

At block570, the control box228may calculate m(a,va) using equation 5. Equation (5) is used to determine the optimum mass of the slug such that it will have velocity vxat position x:
m(x,vx)=(2*c*e−2cx)/(c*vx2+g*(1−e−2cx))*∫0xe2cz*F(T(z))dz(5)

At block572, the control box228may calculate “a” using equation (7). Equation (7) is used to determine the position “a” of the bottom edge of the slug in the first pipe161in meters when the top edge reaches the top of the first pipe161. Equation (7) is:
a=a(H,m,D,ts)=H−(4*m)/(π*D2*ρw(ts))  (7)

At block573, the control box228may calculate vausing equation (6).

After block573, flow may continue to568. Blocks568-572may be a while loop to converge on optimum “m” and “a.”

At block574, the control box228may calculate v1(x) using equation (8), calculate v2(x) using equation (6), and calculate v(x) using equation (9).

Equation (6) is used to determine the velocity “v2(x)” of the slug at position x from a to H, and is the minimum velocity necessary for the slug to have at position x when the top edge of the slug reaches the top of the first pipe161, in order to completely clear the top of the first pipe161. Equation (6):
v2(x)=sqrt((g/c)*[e2c(H-x)−1]−((2*e−2cx)/(ρ*A))*∫Hx(e2cz*F(T(z)))/(H−z)dz)  (6)

Equation (8) may give the velocity of the slug from 0 to “a”:
v1(x)=sqrt(((2*e−2cx)/m)*∫0x(e2cz*F(T(z)))dz−(g/c)(1−e−2cx))  (8)

Equation (9) is used to determine the velocity of the slug up the pipe at position x. Equation (9) may be a concatenation of v1(x) and v2(x) and may provide the velocity of the slug from 0 to H::
v(x)=v1(x), for 0≤x≤a; v(x)=v2(x), fora≤x≤H(9)

At block576, M(τ) with heat loss may be recalculated (using an IVP solver) using equation (1). At block576, M(τ) with heat loss may be recalculated resetting “k” to its true value.

After block576, flow may continue to block562. At block562, M0and M may be recalibrated to make up for the volume in the drum that will be occupied by steam as the liquid water changes to steam, using a bisection method to find the correct value of M0such that X(TC)=H. A while loop may be used to repeat recalculating M(τ) using equation 1 and recalibrating M0 and M using the bisection method until X(TC)=H and X(TH)=0 (with a threshold tolerance).

A while loop may be used to repeat blocks564-562until M(TC) converges. Values for “a,” “m(x,vx),” “v1(x),” “v2(x),” and “v(x)” may be recalculated using equations (7), (5), (8), (6), (9), and using the new M and M0.

At block578, the control box228may calculate power and efficiency of the system. In some embodiments, the time for the slug to spill over the top of the first pipe161may be calculated. In some embodiments, the theoretical efficiency of the system may be calculated.

At block580, the control box228may generate a final output of m, M0, power, and efficiency. To calculate power, the time for each cycle is calculated, work output per cycle is calculated, and then power is calculated. Time for each cycle may be calculated by integrating 1/v(x) from zero to H. Work output per cycle may be calculated as the mass of the slug times g times the height of the water tower. Power may be calculated as work over time.

Efficiency may be calculated as the work output divided by the energy input. Energy input may be calculated as the internal energy of the liquid water at THwhen the liquid water is put into the drum222minus the internal energy of the water at the end of the cycle at TC.

The control box228may compute values for m and M0. The values for m and M0may be used to find intermediate values that optimize power and efficiency according to the needs of an operator of the system.

In some embodiments, the control box228may perform operations a)-t) to calculate optimum slug mass and velocity of the slug if M0is increased beyond the ideal amount.

At operation a), the control box228may determine the value for M0has been increased beyond the ideal value by multiplying M0by a factor greater than 1.

At operation b), the control box228may set the value of “k” to 0 (k=0) and M(τ) may be recalculated with the new M0from operation a).

At operation c), the control box228may recalculate X(T) and T(x).

At operation d), the control box228may set the value for “a” to ideal “a” for optimum M0found in block562(e.g., recalculating values for “a,” “m(x,vx),” “v1(x),” “v2(x),” and “v(x)” using equations (7), (5), (8), (6), (9), and using the new values for M and M0).

At operation e), the control box228may set the value for “a” to a=H−((H−a)*factor) where factor is the factor by which M0is increased from the ideal.

At operation f), the control box228may identify the points so in the interval [a,H], where the force of the steam and the force of gravity on the slug are of equal magnitude. A bisection method may be used to find so such that the following equation is used:
−g+Force(T(s0))/(ρ*A*(H−s0))=0.

At operation g), the control box228may estimate the value of “va” to be equal to v2(a) from the ideal case.

At operation h), the control box228may calculate the square of the velocity of the slug at point so given velocity “va” when the top edge of the slug reaches the top edge of the first pipe161using equation (10):
vns(y,va)=va2*e−2c(y-a)+(2*e−2cy)/(ρ*A)*∫aye2cz*F(T(z))/(H−dz−(g/c)*[1−e−2c(y- a)]   (10)

At operation i), the control box228may use a bisection method to find the minimum (within a threshold tolerance) value for “va” such that “vns(s0,va)” is greater than zero.

At operation j), the control box228may recalculate m(a,va) using equation (5).

At operation k), the control box228may recalculate “a” using equation (7).

At operation l), the control box228may loop back to operations f) through k) until “a” converges.

At operation m), the control box228may calculate vn(x) using the following equation: vn(x)=sqrt (vns(y,va)).

At operation n), the control box228may redefine v1(x) using equation (4) with the new “m” and the control box228may define v(x) (the velocity of the slug) to be v1(x) on the interval [0,a] and vns(x) on the interval [a,H].

At operation o), the control box228may recalculate M(τ) using the value of v(x) (e.g., the velocity function selected in operation n) (v1(x) or vns(x))).

At operation p), the control box228may recalculate X(T) and T(x).

At operation q), the control box228may loop back to operations f) through p) until M(TC) converges.

At operation r), the control box228may repeat operations i) through n) to calculate “a,” “m,” and “v(x).”

At operation s), the control box228may calculate the time for the slug to spill over the top of the first pipe161.

At operation t), the control box228may determine power, efficiency, and the max theoretical efficiency of the system.

The following variables may be used in the equations disclosed herein.

The variable “A” is the cross sectional area of the pipe in meters squared (m2).

The variable “a” is the position of the bottom edge of the slug on the pipe in meters (m) when the top edge reaches the top of the pipe, and is defined by a=a(H, m, D, ts).

The variable “c” is the friction coefficient, defined as c=λ/(2*D).

The variable “D” is the diameter (m) of the pipe.

The variable “d” is the thickness (m) of pipe insulation.

The variable “F(τ)” is the net force in Newtons (N) pushing on the slug by the saturated steam below and above it, when τ is the temperature of the saturated mixture below the slug, and is defined by F(τ)=A*(P(τ)−P(TC)).

The variable “g” is the acceleration of gravity in meters per second squared (m/s2).

The variable “H” is the height (m) of the pipe.

The variable “K” is a constant used in determining the initial guess of M0.

The variable “k” is a constant defined by k=K0*π*D/d.

The variable “K0” is the thermal conductivity constant of the pipe insulation in Watts per meter-Kelvin (W/(m*K)).

The variable “λ” is the Darcy-Weisbach friction coefficient which is dependent on velocity, but may be approximated as a constant between 0.018 and 0.007.

The variable “m” is the mass of the slug in kilograms (kg).

The variable “M” is the mass (kg) of the liquid water remaining in the drum222at temperature τ, and is defined by M=M(τ).

The variable “m(x,vx)” is the optimum mass (kg) of the slug such that the slug will have velocity “vx” at position “x.”

The variable “M0” is the mass (kg) of water injected into the drum222.

The initial guess of the variable “M0” is the first guess at how much hot water to put in the drum222.

The variable “P(τ)” is the saturation pressure in Pascals (P) of the saturated mixture below the slug at temperature “τ.”

The variable “ρst(τ)” is the saturation density in kilograms per meters cubed (kg/m3) of the steam at temperature “τ.”

The variable “ρw(τ)” is the saturation density (kg/m3) of the liquid water at temperature “τ.”

The variable “s0” is the point in the interval [a, H] where the force of the steam and the force of gravity on the slug are of equal magnitude.

The variable “ts” is the inlet temperature of the slug in degrees Celsius (SC).

The variable “Tatm” is the temperature (° C.) of the atmosphere outside the system (e.g., system100,200, and/or300).

The variable “TC” is the saturation temperature (° C.) in the condenser130.

The variable “TH” is the initial temperature (° C.) of the saturated mixture in the drum222.

The variable “T(x)” is the temperature (° C.) of the saturated mixture below the slug when the bottom edge of the slug is at position “x.”

The variable “uf(τ)” is the specific internal energy in kilojoule per kilogram (kJ/kg) of the saturated liquid water at temperature “τ.”

The variable “ug(τ)” is the specific internal energy (kJ/kg) of the saturated water vapor at temperature “τ.”

The variable “va” is the velocity in meters per second (m/s) of the slug at position “a.”

The variable “v1(x)” is the velocity (m/s) of the slug up the first pipe161at position “x” from 0 to “a.”

The variable “v2(x)” is the velocity (m/s) of the slug at position “x” from “a” to “H,” and is the minimum velocity necessary for the slug to have at position “x” when the top edge of the slug reaches the top of the first pipe161, in order to completely clear the top of the first pipe161.

The variable v(x) is the velocity (m/s) of the slug up the first pipe161at position x.

The variable “vns(y,va)” is the square of the velocity of the slug at position “y” from “a” to “H” given the velocity at point “a” is “va,” in the case of when “F(τ)” is greater than zero at “H.”

The variable “vx” is the velocity (m/s) of the slug at position “x.”

The variable “υmax” is the maximum volume in meters cubed (m3) that the steam will occupy before the slug completely leaves the first pipe161. In some embodiments, the volume of the steam in the drum is disregarded and “υmax” is the volume of the pipe and is defined by υmax=A*L, where L is the length of the pipe.

The variable “X(τ,M)” is the position (m) of the bottom edge of the slug up the first pipe161, at temperature “τ” and mass “M.”

The variable “x” is the position (m) of the bottom edge of the slug up the first pipe161in meters.

FIG.6illustrates a component diagram of a computer system which may implement one or more methods of generating electrical power or computing values for generating electrical power described herein. A set of instructions for causing the computer system600to perform any one or more of the methods discussed herein may be executed by the computer system600. In one embodiment, the computer system600may implement the functions of the control box228ofFIGS.2and/or3.

In one embodiment, the computer system600may be connected to other computer systems by a network601provided by a Local Area Network (LAN), an intranet, an extranet, the Internet or any combination thereof. The computer system may operate in the capacity of a server or a client machine in a client-server network environment or as a peer machine in a peer-to-peer (or distributed) network environment. The computer system may be a personal computer (PC), a tablet PC, a set-top box (STB), a Personal Digital Assistant (PDA), a cellular telephone, a web appliance, a server, a network router, switch, bridge or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while a single machine is illustrated, the term “computer system” shall also be taken to include any collection of machines (e.g., computers) that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.

In one embodiment, the computer system600includes a processing device602, a main memory604(e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM) such as synchronous DRAM (SDRAM), etc.), a static memory606(e.g., flash memory, static random access memory (SRAM), etc.) and a data storage device616, which communicate with each other via a bus608.

In one embodiment, the processing device602represents one or more general-purpose processors such as a microprocessor, central processing unit or the like. Processing device may include any combination of one or more integrated circuits and/or packages that may, in turn, include one or more processors (e.g., one or more processor cores). Therefore, the term processing device encompasses a single core CPU, a multi-core CPU and a massively multi-core system that includes many interconnected integrated circuits, each of which may include multiple processor cores. The processing device602may therefore include multiple processors. The processing device602may include a complex instruction set computing (CISC) microprocessor, reduced instruction set computing (RISC) microprocessor, very long instruction word (VLIW) microprocessor, processor implementing other instruction sets or processors implementing a combination of instruction sets. The processing device602may also be one or more special-purpose processing devices such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), network processor or the like.

The processing device602may be the processing device of control box228(seeFIGS.2-3). The processing device602may include one or more interfaces to connect to one or more of valves150, sensors, pumps (e.g., air pump226, pump224), value control interfaces, etc.

In one embodiment, the computer system600may further include one or more network interface devices622. The computer system600also may include a video display unit610(e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)), an alphanumeric input device612(e.g., a keyboard), a cursor control device614(e.g., a mouse) and a signal generation device620(e.g., a speaker).

In one embodiment, the data storage device618may include a computer-readable storage medium624on which is stored one or more sets of instructions654embodying any one or more of the methods or functions described herein. The instructions654may also reside, completely or at least partially, within the main memory604and/or within the processing device602during execution thereof by the computer system600; the main memory604and the processing device602also constituting machine-readable storage media. The computer-readable storage medium624may be a non-transitory computer-readable storage medium.

While the computer-readable storage medium624is shown as a single medium, the term “computer-readable storage medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database and associated caches and servers) that store the one or more sets of instructions. The term “computer-readable storage medium” shall also be taken to include any medium that is capable of storing, encoding, or carrying a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methods described herein. Examples of computer-readable storage media include, but not limited to, solid-state memories, optical media and magnetic media.

FIG.7is a schematic diagram illustrating a system700to generate electrical power, according another embodiment. System700may be an example of system100A ofFIG.1Aand/or system100B ofFIG.1B. One or more of elements inFIG.7that have a similar reference number as elements inFIGS.1-3may include similar features and similar functionality as one or more of the elements described in relation toFIGS.1-3. One or more of the elements described in relation to system700may be used in one or more of systems100,200, or300(e.g., systems100,200, or300may use one or more of a piston710, piston rod, ball valve730, etc.). System700may be a heat engine that transforms a low-level temperature differential between a heat source and a heat sink into useful electrical power. System700may be a hybrid heat engine (e.g., piston-operated hybrid heat engine). A hybrid heat engine may produce electric power from a lower temperature heat source, For example, a hybrid heat engine may combine characteristics of a steam engine and a power plant (e.g., hydropower plant) to economically produce electric power from a low temperature heat source.

System700may be coupled to a hot reservoir212(e.g., of a steam source, heat source110), a disposal sink214, and a cold reservoir216(e.g., heat sink120). System700may include or may be coupled to a drum222and a pump224. System700may include an air pump226(e.g., priming pump) and control box228. System700may include valves including one or more of a first valve151, a second valve152, a third valve153, a fourth valve154, a fifth valve155, a ball valve730, a push valve, etc. One or more of the valves of system700may be controlled by control box228. The control box228may also control the air pump226and the pump224. One or more valves (e.g., push valve of piston710, first valve151of piston rod720, fifth valve155, etc.) of system700may not be controlled by the control box228. System700may include one or more of a first pipe161, a second pipe162, a third pipe163, a fourth pipe164, or a fifth pipe165.

System700may be a heat engine that is coupled to a heat source and a heat sink. The heat engine may include a working fluid and may generate electrical power. The heat sink may be the cold reservoir216. The cold reservoir216may be located at a base of the turbine140. Cooling water and condensate from the turbine140may pass (e.g., be output) to the cold reservoir216(e.g., after use). The heat source may be the hot reservoir212. The hot reservoir212may be part of the heat source110(e.g., steam source). In some embodiments, the hot reservoir212may be at a lower elevation than at least a portion of the liquid in the condenser130(e.g., at a lower elevation than liquid in the water tower180) and the cold reservoir216may be at a lower elevation than the hot reservoir212.

System700may be coupled to a heat source110(e.g., steam source). System700may include one or more components of the heat source110(e.g., steam source). The heat source110(e.g., steam source) may include a hot reservoir212that is fluidly coupled to a drum222via a fourth pipe164. Hot reservoir212may be the source of heat into the system700. A ball valve730may be disposed in the fourth pipe proximate the hot reservoir212. The ball valve730may be controlled by the control box228. A third valve153may be disposed in the fourth pipe proximate the drum222. Third valve153may be a ball solenoid valve (BSV) (see BSV1000ofFIGS.10A-B). Control box228may control flow of hot water into the lower portion of the drum222by controlling third valve153.

The drum222may include a piston710disposed within the drum222. The piston710may be sealed to the walls of the drum222with a piston ring. The piston710may slide up and down within the drum222(e.g., maintaining the seal).

A piston rod720may be located on the piston710(e.g., piston rod720may be secured to the piston710). The piston rod720may be hollow and perforated (e.g., perforated proximate the juncture with the piston710). Perforation of the piston rod720may allow saturated water vapor to enter the piston rod720. A piston ring may seal the piston rod720against the interior wall of the first pipe161and may allow the piston rod720to slide within the first pipe161.

The piston710may include a push valve and the drum222may include a bumper on an upper inner surface (e.g., above the piston710) of the drum222. The piston710may move up and down in the drum222, causing the piston rod720to move up and down in the drum222. An inner volume of the drum222located above the piston710may be referred to as an upper portion of the drum222and an inner volume of the drum222located below the piston710may be referred to as a lower portion of the drum222. Upon the piston710rising above a threshold height, the push valve of the piston710may hit the bumper (e.g., a component of the push valve may push against the bumper) of the drum222and cause liquid to drain from the upper portion of the drum222to the lower portion of the drum222. The piston710may have a concave upper surface to cause liquid in the upper portion of the drum222to pool and to drain through the push valve responsive to the push valve hitting the bumper. In some embodiments, the control box228may control flow of condensate from the upper portion to the lower portion by controlling the push valve.

A fifth pipe165may be disposed between the lower portion of the drum222and a disposal sink214. A fifth valve155may be disposed in the fifth pipe165. Fifth valve155may be a low pressure valve (LPV) (e.g., see LPV1100ofFIG.11). The LPV may open responsive to pressure being below a threshold amount and may close responsive to the pressure being above the threshold amount. In some embodiments, control box228may control flow of hot water to the disposal sink214by controlling fifth valve155. The fifth pipe165may be a condensation and spent hot water drain. Fifth pipe165may evacuate spent hot water and condensation from system700(e.g., from drum222) to the disposal sink214(e.g., responsive to fifth valve155opening). Disposal sink214(e.g., hot water disposal) may be a receptacle for disposing of hot water and condensate from the system700(e.g., drum222) from which useful energy has been extracted. In some embodiments, a pump224is disposed in the fifth pipe165. Pump224(e.g., spent hot water ejection pump) may evacuate water from the fifth pipe165(e.g., condensation and spent hot water drain, drum222, lower portion of drum222). System700may not include pump224responsive to disposal sink214being a threshold distance below the fifth valve155.

A second pipe162may be disposed between an upper portion of the drum222and the fifth pipe165. Second pipe162may be a depressurization channel. Second pipe162may equalize pressure between the upper portion of drum222and lower portion of drum222at a specified instance (e.g., second pipe162may have a valve to selectively equalize pressure between the upper and lower portions).

A first pipe161(e.g., pipe tower) may be disposed between the heat source110(e.g., steam source) (e.g., upper portion of the drum222) and an inlet (e.g., water inlet132and steam inlet134) to the condenser130. The first pipe161(e.g., pipe tower) may be a vertical pipe that conducts the water column (e.g., first amount of water, slug of water) to the condenser130and/or the water tower180. The first pipe161may be sealed to the upper portion of the drum222. Water may enter the first pipe161at SIB170(e.g., at a slug intake, at a vertical portion of the first pipe161) via a second valve152from the cold reservoir216. The SIB170may be a SIB as illustrated in one or more ofFIGS.1-3. The SIB170may be a slug intake portion of the first pipe161with a bend (e.g., a slug intake bend) or without a bend (e.g., a slug intake). SIB170may be a vertical portion of the first pipe161. The steam in the drum222may push, using piston rod720, a slug of cold water through the SIB170, up the first pipe161, into the inlet of the condenser130, and to the water tower180to power the turbine140.

The second valve152may be a check valve that allows cold water to enter the first pipe (e.g., enter the SIB170from the cold reservoir216). The second valve152may be situated at a threshold height such that a vacuum created in the pipe161when the piston710and the water column separate (e.g., the piston rod720falls) is sufficient to suck water through the second valve152from the cold reservoir216.

A check valve may be included proximate the inlet (e.g., water inlet132, steam inlet134) of the condenser130and/or proximate the SIB170to prevent water column (e.g., slug, first amount of water) from falling back down after being propelled up the first pipe161. System700may not include a check valve proximate the inlet if the rate of flow from the second valve152is at least a threshold flow rate.

In some embodiments, condenser130may include a portion of first pipe161and a water tower180(e.g., cold water tower). Water tower180may be an elevated tank into which cold water is propelled from the first pipe161by the piston rod720. Water vapor may enter the condenser130(e.g., from an upper portion of the drum222) via a first valve151disposed in an upper surface of the piston rod720. The first valve151may be a check valve that allows water vapor and incondensable gases to be ejected from the piston rod720into the first pipe161. In some embodiments, the water vapor may condense by contacting the water disposed in the first pipe161. In some embodiments, the condenser130may be a condenser130as described in relation to one or more ofFIGS.1-3. The condenser130may include or may be coupled to an air pump226. Air pump226(e.g., priming pump) may initiate the first cycle by evacuating air from system700(e.g., first pipe161). The turbine140may convert the potential energy of the liquid in the water tower180to electrical power.

Variables PL, PU, P0, P1, and P2 may be used to describe system700. PL may be pressure in a lower portion of the drum222(e.g., below piston710). PU may be pressure in an upper portion of the drum222(e.g., above piston710). P0 may be saturation pressure of water at temperature of the cold reservoir216. P1 may be a specified pressure that is greater than P0. Fifth valve155may open when PL<P1 and may close when PL>P1. P2 may be P0 plus crack pressure of first valve151(e.g., crack pressure may be pressure when first valve151opens to insert water vapor and non-condensable gases in the first pipe161).

The control box228may control third valve153to inject hot water from the hot reservoir212into the drum222at the beginning of a cycle. The control box228may open the third valve153for a specified amount of time and then close the third valve153to insert a controlled (e.g., predetermined) amount of water into a lower portion of the drum222(e.g., below piston710). Expanding steam from the hot water inserted into the drum222may push up on the piston710and may shut the fifth valve155as P1 is exceeded in the lower portion of the drum222.

The control box228may control second valve152to inject a first amount of cold water from the cold reservoir216into the first pipe161(e.g., SIB170, pipe tower).

The expanding steam (e.g., in the lower portion of the drum222, fueled by the hot reservoir212) may push the first amount of cold water (e.g., a column of water, slug of water) up the first pipe161(e.g., pipe tower). As the steam expands, the pressure may decrease in the lower portion of the drum222(e.g., below the piston710) and pressure may increase in the upper portion of the drum222(e.g., above the piston710). The expanding steam may push the piston710which pushes the piston rod720which pushes the first amount of cold water (e.g., column of water) up the first pipe161(e.g., pipe tower).

System700may utilize steam at a lower pressure to elevate a water column (e.g., slug, first amount of water) at a higher pressure to generate electrical power from the higher pressure water column and a turbine140(e.g., hydro-electric turbine). System700may take advantage of a piston710with a surface area greater (e.g., 10-100 times greater) than the cross-sectional area of the water column (e.g., cross-sectional area of the first pipe161) the piston710is elevating. The piston710may be pushed from below by hot saturated steam in the lower portion of the drum222while colder, low pressure saturated steam is maintained in the upper portion of the drum222. System700may push water against gravity and against atmospheric pressure to elevate the water to a water tower180, from which the water falls through a turbine140to generate electrical power. System700may utilize the same cold water the system700is elevating to cool and condense the vapor in the upper portion of the drum (e.g., that enters the first pipe161via first valve151), thus maintaining a low pressure in the upper portion of the drum222.

Once PL is less than P1, fifth valve155opens. Cooled water in the drum drains out of the drum222. Pressure in the upper portion of the drum222and pressure in the lower portion of the drum222may be equalized (e.g., responsive to fifth valve155opening). The piston710may continue to rise under the kinetic energy of the piston710. The column of water may also continue to rise.

Responsive to the push valve of the piston710colliding with the bumper of the drum222, condensate from the upper portion of the drum222may flow into the lower portion of the drum222via the push valve and the piston710and piston rod720may accelerate downward.

The column of water may continue to rise under its kinetic energy as the piston710and piston rod720move downward. A lower pressure P0 may be created in the first pipe161(e.g., pipe tower) above (e.g., immediately above) the piston rod720and first valve151in the upper surface of the piston rod720may open, releasing saturated vapor and non-condensable gases into the first pipe161until the pressure in the drum222decreases to P2.

Once the column of water passes second valve152, second valve152opens as the pressure on the downstream side is reduced. Cold water (e.g., from the cold reservoir216) may enter the first pipe161and may fall toward the piston rod720and may be sucked up towards the rising column of water. In some embodiments, the falling cold water may condense (e.g., acting as a condenser130) the higher pressure vapor that entered the first pipe161through the first valve151. In some embodiments, a separate condenser130may be used to condense the higher pressure vapor. In some embodiments, the water tower180may be a condenser130(e.g., condenser130of one or more ofFIGS.1-3).

Responsive to the piston710reaching the bottom of the drum222, cold water has filled the space between the piston rod720and the column of water in the first pipe161. The cycle is complete. More hot water may be injected in the lower portion of the drum222to start a new cycle.

In some embodiments, system700may be more efficient, more powerful, and less costly that systems200and300. System700may operate at a slower velocity than systems200and300, thus reducing friction losses. In some embodiments, system700works against atmospheric pressure, thus reducing height required for the water tower180(e.g., condenser130), thus reducing costs. In some embodiments, system700condenses the water vapor in the first pipe161(e.g., first pipe161acts as a condenser130), which may eliminate use of a separate condenser and further reduce costs.

In some embodiments, the upper portion of the drum222is maintained at a constant low pressure by pumping cold water over or through the upper portion of the drum222(e.g., to raise efficiency of the system700).

In some embodiments, the upper portion of the drum222is maintained at a constant low pressure by being connected to an external condenser (e.g., condenser130) (e.g., to raise efficiency of the system700and may eliminate the need of a check valve proximate the inlet (e.g., water inlet132, steam inlet134)).

FIG.8is a flow diagram of a method800of generating electrical power, in accordance with embodiments of the present disclosure. The method800may be performed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (e.g., instructions run on a processor to perform hardware simulation), or a combination thereof. In one embodiment, the method800may be performed by system100A ofFIG.1Aand/or system100B ofFIG.1B. In one embodiment, the method800may be performed by system700or control box228ofFIG.7. In one embodiment, the method800may be performed by a processing device of a control box228of a heat engine. Alternatively, the method800can be performed by other components as described herein.

In method800, variables PL, PU, P0, P1, and P2 may be used. PL may be pressure in a lower cylinder below the piston. PU may be pressure in an upper cylinder, above the piston. PO may be saturation pressure of water at temperature of the cold reservoir. P1 may be a specified pressure that is greater than P0. Valve2may open when PL<P1 and may close when PL>P1. P2 may be P0 plus crack pressure of valve4.

Referring toFIG.8, at block802, in some embodiments, the control box228implementing the method may control an air pump to initiate a cycle by evacuating air from a first pipe161coupled between a heat source110(e.g., steam source) and a water inlet of a condenser130.

At block804, the control box228may control a second valve152to inject a first amount of cold water from a cold water source (e.g., heat sink120) into a slug inlet of the first pipe161.

At block806, the control box228may control a third valve153to inject a first amount of steam, fueled by the heat source110(e.g., steam source), to push the first amount of cold water as a slug of water through a vertical portion of the first pipe upwards to the water inlet132of the condenser130.

In some embodiments, at block806, the control box228opens the third valve153for a predetermined amount of time and then closes the third valve153to cause a predetermined amount of hot water to enter a lower portion of a drum222(e.g., under piston710). Expanding steam from the hot water may push up on the piston710and shut fifth valve155responsive to pressure PL in the lower portion of the drum222exceeding pressure P1. As the piston710rises, pressure PL in the lower portion of the drum222may lower and the pressure PU in the upper portion of the drum222may rise. The rising piston710may cause the piston rod720to rise and push a column of water up the first pipe161.

Once pressure PL is less than pressure P1, the fifth valve155opens and cooled water in the lower portion of the drum222drains out of the drum222. In some embodiments, the control box228may control fifth valve155and/or pump224to drain the lower portion of the drum222. As the cooled water in the lower portion of the drum222drains out of the drum222, pressure in the upper and lower portions of the drum222may be equalized. The piston710may continue to rise based on the kinetic energy of the piston710which causes the column of water to rise. A push valve of the piston710may hit a bumper at an upper inner surface of the drum222, causing the push valve to open and allow accumulated condensate from the upper portion of the drum222to drain into the lower portion of the drum222. The piston710and piston rod720may accelerate downward responsive to the push valve hitting the bumper. The column of water may continue to rise based on the kinetic energy of the column of water as the piston710and piston rod720move downward.

A low pressure P0 is created in the first pipe161proximate an upper surface of the piston rod720(e.g., responsive to the piston rod720moving downward) which causes first valve151to open. The opening of first valve151causes saturated vapor and non-condensable gases to be released from upper portion of the drum222(e.g., via the piston rod720) into the first pipe161, causing the pressure in the drum222to decrease to P2. Once the column of water passes the second valve152(e.g., SIB170), the second valve152opens as the pressure of the downstream side is reduced. Cold water may rush into the first pipe161and fall toward the piston rod720and may be sucked up toward the rising column of water. The falling cold water may condense the higher pressure vapor that entered the first pipe161via the first valve151. Responsive to the piston710reaching the bottom of the drum222, cold water has filled the space between the piston rod720and the column of water in the pipe tower and the cycle is complete.

At block808, the control box228may control a fourth valve154to allow liquid water from a water outlet of the condenser130to fall though a third pipe to an input of the turbine140.

FIG.9Aillustrates a P-v diagram900A of a hybrid heat engine, according to certain embodiments.FIG.9Billustrates a T-s diagram900B of a hybrid heat engine, according to certain embodiments. A heat engine of the present disclosure (e.g., one or more of system100, system200, system300, or system700) may approximate a thermodynamic cycle shown in the P-v diagram900A ofFIG.9Aand/or T-s diagram900B ofFIG.9B. From steps 1-2, the heat engine may have a substantially constant volume heat addition. From steps 2-3, the heat engine may have a substantially isentropic expansion. From steps 3-1, the heat engine may have a substantially constant temperature/pressure heat rejection.

FIGS.10A-Band11illustrate valves that may be used in a heat engine (e.g., one or more of system100, system200, system300, or system700).

FIGS.10A-Billustrate a ball solenoid valve (BSV)1000, according to certain embodiments. In some embodiments, the third valve153is a BSV1000. For example, third valve153ofFIG.7that allows hot water to flow from the hot reservoir212into the lower portion of the drum222may be a BSV1000. The BSV1000may be an automated valve that cycles very quickly. The BSV1000may be configured for low pressures in heat engines (e.g., one or more of system100, system200, system300, or system700). The BSV1000may have an internal seal (e.g., O-ring) that may be quickly and easily replaced as needed instead of replacing the BSV1000.

The BSV1000may have a solenoid coil1002. The BSV1000may have end caps1008(e.g., end caps of a spool) and the solenoid coil1002may be located between the end caps1008. The solenoid coil1002may have multiple turns.

The BSV1000may have a ball1004.

In some embodiments, as shown inFIG.10B, the BSV1000has a reducer. In some embodiments, BSV1000has a coupling instead of a reducer and an O-ring1006is between the tubes inserted in the coupling. In some embodiments, the ball1004in the BSV1000may be a440C stainless steel. The BSV1000may have an O-ring1006that is one or more of a rubber, an elastomer, an ethylene propylene diene monomer (EPDM) material, an EPDM rubber, an EPDM elastomer, etc. The O-ring1006may be sized to fit around the ball1004. In some embodiments, the BSV1000has an O-ring1006configured to fit around the ball1004to allow a faster flow rate and less force to break the seal. The maximum temperature used with BSV1000may be about 250 degrees Fahrenheit. The BSV1000may be at least partially surrounded by insulation.

FIG.11is a low pressure valve (LPV)1100, according to certain embodiments. In some embodiments, fifth valve155is a LPV1100. For example, fifth valve155ofFIG.7that allows hot water that has cooled to drain from the lower portion of the drum222to the disposal sink214may be a LPV1100. An LPV1100may open at a specified low pressure and closes when that pressure is exceeded. An LPV1100may open when a pressure differential between the upstream side and the downstream side falls below a specified value. The LPV1100may be used in heat engines (e.g., one or more of system100, system200, system300, or system700).

Responsive to pressure differential dropping below an established baseline, a coil1102(e.g., spring) lifts the ball1104and opens the LPV1100. In some embodiments, the ball1104may be one or more of a rubber, an elastomer, an EPDM material, an EPDM rubber, an EPDM elastomer, etc. In some embodiments, the ball1104may be metal (e.g., stainless steel, in lieu of a rubber ball) and there may be an O-ring similar to in the BSV1000to create the seal (e.g., between the ball1104that is metal and an inner surface of the LPV1100). The maximum temperature the LPV1100may withstand may be about 250 degrees Fahrenheit. The coil1102(e.g., spring) may rest inside a copper tube on a punctured copper plug rest soldered inside the tube.

FIG.12is a schematic diagram illustrating a system1200(e.g., system100A ofFIG.1A) to convert energy, according to certain embodiments. Elements inFIG.12that have a similar reference number as elements in other FIGS. (e.g.,FIG.1A,FIG.1B,FIG.2,FIG.3,FIG.7) may include similar features and/or similar functionality. System1200may be a heat engine that transforms a low-level temperature differential between a heat source110and a heat sink into useful power. System1200may be a hybrid heat engine. System1200may be a steam powered hydraulic ram (e.g., steam hydram.) System1200may produce power from a lower temperature heat source. For example, a steam system1200may combine characteristics of a steam engine and a power plant (e.g., hydropower plant) to economically produce power from a low temperature heat source.

System1200may be coupled to a heat source110(e.g., hot reservoir212), and a heat sink120(e.g., cold source1216, cold reservoir216, located proximate the output of the turbine140). System1200may include pipes including one or more of a first pipe1261, a second pipe1262, a third pipe1263, and a fourth pipe1264. System1200may include valves including one or more of a first valve1251, a second valve1252, a third valve1253, a fourth valve1254, a fifth valve1255, a sixth valve1256, and a seventh valve1257. One or more of the valves of system1200may be controlled by the control box228. One or more valves of system1200may not be controlled by the control box228.

Cooling water and condensate from the turbine140may pass (e.g., be output) to the heat sink120(e.g., after use). The turbine140may be a high-pressure turbine. The heat source110may have a hot reservoir212. In some embodiments, the hot reservoir212is not elevated above the remainder of system1200. The heat sink120may be at a lower elevation than the hot reservoir212.

System1200may be coupled to a heat source110. System1200may include one or more components of the heat source110. The heat source110may include a hot reservoir212. The heat source110may include a hot drum1250(e.g., hot water chamber (HWC)). The hot reservoir212and the hot drum1250may be fluidly coupled. The fifth valve1255may be controlled by the control box228. The fifth valve1255may be a ball solenoid valve (BSV) (see BSV1000ofFIGS.10A-B).

The hot drum1250may be fluidly coupled to the chamber1220(e.g., cylinder) and the condenser1230. Flow of fluid (e.g., steam from the hot reservoir212) into the hot drum1250may be controlled by the fifth valve1255. The hot drum1250may be configured to provide fluid (e.g., steam, hot fluid vapor) to the chamber1220. In some embodiments, the hot drum1250is one or more shapes (e.g., cylindrical, non-cylindrical, etc.).

The first valve1251may control the flow of hot fluid to chamber1220. The first valve1251may be a valve assembly that includes one or more valves, fittings, and/or passages (e.g., first valve1251ofFIG.15). The first valve1251may be proximate to the hot end1221of the chamber1220.

In some embodiments, the chamber1220may be cylindrical in shape. In some embodiments, the chamber1220may be situated at an elevation above the cold source1216. This height may be optimized for overall efficiency to the system while still allowing for sufficient vacuum created in the first pipe1261when the piston moves towards the hot end1221to suck working fluid through the second valve1252from the cold source1216. In some embodiments, the chamber1220may be a container capable of holding pressurized fluid. The chamber1220may have two distal ends. In some embodiments, a first distal end of the chamber1220is referred to as hot end1221and is fluidly coupled to the heat source110. In some embodiments, a second distal end of the chamber1220is referred to as cold end1222and is fluidly coupled to the first pipe1261. In some embodiments, the hot end1221and the cold end1222are opposite distal ends of the chamber1220.

The chamber1220may have at least one port (e.g., inlet, outlet). In some embodiments, the chamber1220may have at least two ports (e.g., inlet and outlet). In some embodiments, a port of the chamber1220functions as an inlet and as an outlet (e.g., fluid flows in the chamber1220through the port and flows back out of the chamber1220via the same port). In some embodiments, fluid (e.g., pressurized fluid, steam, working fluid, liquid, gas, etc.) enters and/or exits the chamber1220through one or more ports. In some embodiments, fluid (e.g., pressurized fluid, steam, gas, etc.) may enter and/or exit the chamber1220via a port at the hot end1221. In some embodiments, fluid (e.g., working fluid, water, etc.) may enter and/or exit the chamber at the cold end1222.

The chamber1220is a structure (e.g., a chamber structure that has chamber walls) that at least partially encloses an interior volume (e.g., forms a cavity). In some embodiments, a piston is disposed in the chamber1220. In some embodiments, the piston divides an upper portion of the inner volume of chamber1220from a lower portion of the inner volume of the chamber1220. In some embodiments, the upper portion of the inner volume is sealed off from the lower portion of the inner volume via the piston (e.g., the sidewalls of the piston engage with the inner sidewalls of the chamber to prevent fluid from passing the piston). The piston may have an upper surface and a lower surface that is opposite the upper surface. The upper surface of the piston may face the hot end1221and the lower surface of the piston may face the cold end1222. In some embodiments, the piston may be a fluid piston. The fluid piston includes a slug of fluid (e.g., liquid, water, a layer of oil on a layer of water, etc.). In some embodiments, the piston is solid. In some embodiments, the piston may be constructed of metal. The piston may move in two directions along the axis of the chamber1220. The movement of the piston within chamber1220may be cyclic. The piston may move within chamber1220responsive to fluid (e.g., steam from the heat source110, working fluid from the first pipe1261, etc.) exerting pressure. In some embodiments, fluid may exert pressure on one or both sides of the piston.

The chamber1220may contain pressurized gas. In some embodiments, the pressurized gas may be at the hot end1221. The pressurized gas may exert pressure on the upper surface of the piston that faces the hot end1221. The pressurized gas may be able to flow into and out of the chamber1220responsive to the opening and closing of the first valve1251. The pressurized gas may flow out of the chamber1220responsive to the movement of the piston.

The chamber1220may contain working fluid. In some embodiments, the working fluid may be contained at the cold end1222. The working fluid may be a liquid. In some embodiments, the working fluid may be water. In some embodiments, the working fluid may be a refrigerant. The working fluid may be forced out of the chamber1220responsive to the movement of the piston. The working fluid may be drawn into the chamber1220responsive to the movement of the piston. The working fluid may exit the chamber1220into the first pipe1261. The working fluid may be drawn into the chamber1220from the first pipe1261. In some embodiments, the working fluid may be drawn into the chamber1220from another pipe.

The first valve1251may include a float valve. The float valve may include a float ball that may cover a port when supported by the piston. The first valve1251may be configured to open when the piston moves away from the hot end and the float ball no longer covers the port. Hot fluid flows into the chamber1220when the first valve1251is open. The hot fluid may be a vapor. In some embodiments, the vapor is steam. Hot fluid may flow out of the chamber1220when the first valve1251is open responsive to the movement of the piston. Hot fluid from the heat source110may expand within the chamber1220. The expanding hot fluid may exert a force on the piston within the chamber1220.

The chamber1220may be fluidly coupled to the first pipe1261. The chamber1220may be fluidly coupled to the condenser1230. The chamber1220(e.g., a lower portion of the inner volume of the chamber1220) may receive working fluid (e.g., condensed steam that was provided from the heat source110) from the condenser1230. The chamber1220may receive working fluid from the first pipe1261. The working fluid in chamber1220may be pushed by the flow of hot fluid into chamber1220. In some embodiments, the hot fluid may push the piston which may push the working fluid. The pressure of the working fluid may be raised when pushed on by the piston. The working fluid may be prevented from flowing back to the condenser1230by the seventh valve1257. The seventh valve1257may be a check valve. The working fluid may flow out of the chamber1220into the first pipe1261.

The first pipe1261may connect the chamber1220with the second pipe1262and the third pipe1263. Working fluid may be pushed from the chamber1220toward the third pipe1263through the first pipe1261. The flow of working fluid through the first pipe1261may include pulsations (e.g., pressure wave, water hammer) of working fluid. The second valve1252and the third valve1253may be at one end of the first pipe1261opposite the chamber1220. The second valve1252may prevent flow of working fluid into the second pipe1262from the first pipe1261.

The second valve1252may include a check valve. The second valve1252may include a reverse float valve (e.g., reverse float valve1900ofFIG.19). The second valve1252may allow cold working fluid from cold source1216to enter the first pipe1261. The second valve1252may also prevent air from entering the first pipe1261. The third valve1253may prevent flow of working fluid from the third pipe1263into the first pipe1261. The third valve1253may be a check valve. The third valve1253may allow flow from the first pipe1261into the third pipe1263only when the pressure of the working fluid in the first pipe1261matches or exceeds the pressure of the working fluid in the third pipe1263.

The third pipe1263(e.g., that includes a penstock, sluice, floodgate, channel for conveying the fluid to the turbine, and/or the like) may couple the first pipe1261with the turbine140. The expansion tank1241may be coupled to the third pipe1263. The third pipe1263and the expansion tank1241may contain working fluid at a higher pressure than working fluid in the first pipe1261. The expansion tank1241may contain an amount of pressurized gas. In some embodiments, the pressurized gas may be air. The expansion tank1241may be configured to regulate the pressure of the working fluid contained in the expansion tank1241and the third pipe1263. The initial pressure within the expansion tank1241may be set by a user of system1200. The pressure inside the expansion tank1241may be set using a valve (e.g., Schrader valve, Presta valve, or equivalent) to inject gas into the expansion tank1241. The volume of the expansion tank1241may be greater than the volume of working fluid flowing into the third pipe1263from the first pipe1261with each pulsation of working fluid. Flow of working fluid from the third pipe1263to the input of the turbine140is regulated by the fourth valve1254. The fourth valve1254may be controlled by the control box228.

The outlet of the turbine140may be connected to the heat sink120(e.g., cold source1216). An amount of working fluid exhausted from the turbine140to the heat sink120may be bled off to a cooling tower1270. The cooling tower1270may be a single cooling tower or a set of cooling towers. The cooling tower1270may utilize liquid to liquid cooling, or air to liquid cooling. In some embodiments, ambient air is used instead of one or more cooling towers. The fourth pipe1264may be fluidly coupled between the heat sink120(e.g., cooling tower1270, cold source1216) and the condenser1230.

The condenser1230may receive cooled working fluid from the heat sink120through the fourth pipe1264. The condenser1230may receive heat source fluid provided by the heat source110(e.g., at least a portion of the fluid is provided by the heat source110to the chamber1220). Expended heat source fluid from the chamber1220may be routed to the condenser1230through the first valve1251, the hot drum1250, the sixth valve1256, and associated piping. The sixth valve1256may be a low pressure valve (LPV) (e.g., LPV1100ofFIG.11). The sixth valve1256may be a solenoid drain valve (SDV) (e.g., SDV1800ofFIG.18) controlled by the control box228. The heat source fluid may enter the condenser1230in a gaseous state (e.g., steam from hot drum1250). Working fluid may enter the condenser1230in a liquid state (e.g., from cooling tower1270). In some embodiments, the heat source fluid and the working fluid are the same fluid in different states of matter (e.g., gas and liquid). Working fluid and heat source fluid may mix inside the condenser1230where the heat source fluid may condense into fully liquid form. The condenser1230may have a perforated plate that serves to direct streams of atomized liquid working fluid. The combined fluid may exit the condenser1230to the chamber1220. The condenser1230may be elevated above the chamber1220to enable draining of the condenser1230. The input of mixed fluid to the chamber1220from the condenser1230may be regulated by the seventh valve1257. The seventh valve1257may be proximate to the chamber1220. The seventh valve1257may only allow flow of fluid away from the condenser1230. The seventh valve1257may be a check valve.

FIG.13is a schematic diagram illustrating a chamber, according to certain embodiments. Elements inFIG.13that have a similar reference number as elements in other FIGS. (e.g.,FIG.1AorFIG.12) may include similar features and/or similar functionality.

The chamber1220may contain a piston. In some embodiments, the piston may be a fluid piston1303(SeeFIG.13). In some embodiments, the fluid piston1303may comprise a liquid. In some embodiments, the fluid piston1303may be water. In some embodiments, the fluid piston1303may comprise a layer of oil and a layer of a different liquid.

The chamber1220may contain pressurized gas1302. The pressurized gas1302may be able to flow into and out of the chamber1220responsive to the opening and closing of the first valve1251. The pressurized gas1302may flow out of the chamber1220responsive to the movement of the piston.

The chamber1220may contain an expansion bladder1305(e.g., bladder structure). The expansion bladder1305may be a doughnut shaped bladder. In some embodiments, the expansion bladder1305may be made of rubber. The expansion bladder1305may be filled with a compressible gas. In some embodiments, the expansion bladder1305may be filled with air. In some embodiments, the expansion bladder1305may be filled with nitrogen.

The chamber1220may contain a balloon1304. The balloon1304may be a partition. In some embodiments, the balloon1304may be compressible. In some embodiments, the balloon1304may compress responsive to the movement of the piston. The balloon1304may be made of a polymer. In some embodiments, the balloon1304is made of butyl rubber. The balloon1304may be a bladder. In some embodiments, the balloon1304may be filled with gas. In some embodiments, the balloon1304may be filled with air. In some embodiments, the balloon1304may be filled with nitrogen. In some embodiments the balloon1304may have no containment (e.g., the balloon1304compresses the gas). The balloon1304may exert pressure on the piston. In some embodiments, the balloon1304may push the piston towards the hot end1221as the balloon expands.

The chamber1220may contain working fluid. The working fluid may be forced out of the chamber1220responsive to the movement of the piston and the balloon1304. The working fluid may be drawn into the chamber1220responsive to the movement of the piston and the balloon1304. The working fluid may exit the chamber1220into the first pipe161. The working fluid may be drawn into the chamber1220from the first pipe1261. In some embodiments, the working fluid may be drawn into the chamber1220from another pipe.

FIG.14is a schematic diagram illustrating a chamber, according to certain embodiments. Elements inFIG.14that have a similar reference number as elements inFIG.1,12, or13may include similar features and similar functionality.

In some embodiments, the chamber1220may be a U-shaped chamber1400(SeeFIG.14). In some embodiments, the chamber1220is a U-shaped body. In some embodiments, the hot end1221and the cold end1222may have similar elevations. In some embodiments, the hot end1221(e.g., the first distal end) may be at a first height. The cold end1222(e.g., the second distal end) may be at a second height. The second height may be at least as high as the first height. The second height may be higher than the first height. In some embodiments, the U-shaped chamber1400may be a U-shaped body that is routed from the first distal end to a third height and is routed from the third height to the second distal end. In some embodiments, the third height may be lower than the first height and the second height. In some embodiments the walls of the chamber may be curved. In some embodiments of the U-shaped chamber, the balloon1304may be a pocket of gas. In some embodiments, the pocket of gas may be a pocket of air.

The U-shaped chamber1400may retain one or more of the features of the chamber1220as already described. For example, the piston may be a fluid piston1303as already described. In some embodiments, the U-shaped chamber1400may receive pressurized gas at the hot end1221. In some embodiments, the U-shaped chamber may push working fluid into the first pipe1261. The U-shaped chamber may contain an expansion bladder1305. The expansion bladder may be contained at the hot end1221.

FIG.15is a schematic diagram illustrating a valve assembly, according to certain embodiments. Elements inFIG.15that have a similar reference number as elements inFIG.1,12,13, or14may include similar features and similar functionality. In some embodiments, the valve assembly illustrated is the first valve1251.

The first valve1251may be a valve assembly that includes valves, fittings, and passages (seeFIG.15). In some embodiments, the first valve1251may include one or more of an outlet ball valve1555, an outlet check valve1556, an Initial Pressure Regulator (IPR) ball valve1554, and a float valve. In some embodiments, the outlet ball valve1555may be made of polyvinyl chloride (PVC). In some embodiments, the outlet check valve1556is made of chlorinated polyvinyl chloride (CPVC). In some embodiments, the IPR ball valve1555may be made of polypropylene or CPVC.

First valve1251may include a gasket1557(e.g., O-ring). In some embodiments, the gasket1557may mate with the float ball1559to form a float valve. In some embodiments, the gasket1557may be disposed within a groove. In some embodiments, the gasket1557may be fastened into the groove by an adhesive. In some embodiments, the float ball1559may be a polypropylene ball. In other embodiments, the float ball1559may be one or more of a rubber, an elastomer, an EPDM material, an EPDM rubber, an EPDM elastomer, etc. In other embodiments, the float ball1559may be a metal (e.g., stainless steel, in lieu of a rubber ball). The float ball1559may be hollow. The float ball1559may be configured to float. In some embodiments, the gasket1557may be the sealing surface for which the float ball1559may seat against. The float ball1559, perforated plate1558, and gasket1557may protrude into the chamber1220. The float ball1559may float on liquid contained within the chamber1220. The float ball1559may be retained by the perforated plate1558and a cylindrical type body. This cylindrical body may be perforated (e.g., one or more sidewalls of the cylindrical body may be perforated) to allow fluid to pass while retaining the ball. The perforated plate may be configured to allow the float ball1559to move a distance from the gasket1557. The perforated plate may be made of CPVC. The combination of the float ball1559, the gasket1557, and the perforated plate1558may be configured to allow the passage of liquid and gas one direction through the first valve1251, but not allow the passage of liquid the opposite direction through the first valve1251.

The first valve1251may include a pressure sensor1560. The first valve1251may include a cross1570. In some embodiments, the cross1570is made of CPVC. The pressure sensor1560may be configured to monitor the pressure of fluid within the cross1570. The pressure sensor1560may send pressure data to a control box.

The first valve1251may include a compressed air reservoir1553. The compressed air reservoir1553may contain an amount of compressed air. The compressed air within the compressed air reservoir1553may be used to initially set the pressure of at least part of system1200. The compressed air reservoir1553may be fluidly connected to the CPVC cross. CPVC ball valve1554may regulate the flow of compressed air to the CPVC cross1570. The CPVC cross1570may receive fluid under pressure from the hot drum1250.

FIG.16Ais a flow diagram of a method1600A of converting energy, according to certain embodiments. In some embodiments, one or more operations of method1600A are performed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, processing device, etc.), software (such as instructions run on a processing device, a general purpose computer system, or a dedicated machine), firmware, microcode, or a combination thereof. In some embodiments, a non-transitory storage medium stores instructions that when executed by a processing device (e.g., of control box228) cause the processing device to perform one or more operations of method1600A. In some embodiments, one or more operations of method1600A are performed by the control box228.

For simplicity of explanation, method1600A is depicted and described as a series of operations. However, operations in accordance with this disclosure can occur in various orders and/or concurrently and with other operations not presented and described herein. Furthermore, not all illustrated operations are performed to implement method1600A in accordance with the disclosed subject matter. In addition, those skilled in the art will understand and appreciate that method1600A could alternatively be represented as a series of interrelated states via a state diagram or events.

In some embodiments, the method1600A is cyclic. In some embodiments, the method1600A may include operations including one or more of setup procedures (e.g., block1601), Stage 0 (e.g., block1602), Stage 1 (e.g., block1603), Stage 2 (e.g., block1604), Stage 3 (e.g., block1605), Stage 4 (e.g., block1606), Stage 5 (e.g., block1607), Stage 6 (e.g., block1608), and Stage 7 (e.g., block1609). In some embodiments, one or more operations the method1600A may repeat. In some embodiments, the method1600A may proceed to Stage 1 (e.g., block1603) after completing Stage 7 (e.g., block1609). The method1600A may be performed by one or more of system100A ofFIG.1A, system1200ofFIG.12, and/or system1700ofFIG.17.

The system1200may operate in a cycle. The cycle may be continuous. In some embodiments, variables Y, PC, PLPV, PB0, PATM, PE0, and PTmay be used to describe the cycle of system1200. Y may be the position of the piston within the chamber1220. Pc may be the pressure maintained in the condenser1230. PLPVmay be the pressure at which the sixth valve1256(e.g., LPV) is set to open. Pb0may be the internal pressure of the balloon1304. PATMmay be atmospheric pressure. PE0may be the pressure of the expansion bladder1305. Ptmay be the pressure within the expansion tank1241.

At block1601, setup procedures are performed. The setup procedures include filling the expansion tank1241and the third pipe1263with working fluid. In some embodiments, the turbine140and the cold source1216may be filled with working fluid. In some embodiments, the second pipe1262is filled with working fluid. The expansion tank is pressurized to PT. In some embodiments, the fourth valve1254is closed to facilitate pressurizing the expansion tank1241. The fourth pipe1264is filled with working fluid. The balloon1304is filled with air at PATM. The cold end1222of the chamber1220is filled with working fluid. In some embodiments, the piston is inserted into the chamber1220. In some embodiments, liquid is poured into the chamber1220to make the fluid piston1303. A vacuum pump may need to be connected to the outlet ball valve1555. The pressure inside the cross1570and the chamber1220is reduced by the vacuum pump to a pressure less than PATM−PLPV. The hot drum1250, the first valve1251, and the hot end1221are preheated. In some embodiments, the fifth valve1255opens to allow atmospheric pressure hot fluid into the hot drum1250. In some embodiments, the vacuum pump is again connected to the outlet ball valve1555. The pressure of the hot end1221, the first valve1251, the hot drum1250, and the condenser1230may be lowered to PC. In some embodiments, the outlet ball valve1555is then closed. Pressurized air may be introduced to the compressed air reservoir1553through the Schrader valve1552. In some embodiments, working fluid is then allowed to flow into the condenser1230. In some embodiments, the IPR ball valve1554is opened. In some embodiments, this brings the pressure inside the cross1570and the hot end1221to PATM. The outlet ball valve1555, and the fourth valve1254may need to be quickly opened. Opening the outlet ball valve1555may allow excess air to be expelled from the hot end1221. Opening the fourth valve1254may allow working fluid to flow through the turbine140. In some embodiments, the cycle begins.

At block1602, operations of Stage 0 is performed. At Stage 0, working fluid may fill the first pipe1261. The piston may be at an initial position Y0and may rest and push down on the working fluid within the chamber1220with a pressure well below PATM. The working fluid within the chamber1220and the first pipe1261may be a fluid column. The fluid column may be prevented from ascending by the second valve1252which may only allow the passage of liquid. Air may be in the hot end1221of the chamber1220. In some embodiments, air in the hot end1221of chamber1220may be at PATM. The sixth valve1256may be closed which may prevent air from passing into the condenser1230. The first valve1251may be configured so that the float valve (e.g., the combination of the float ball1559and the gasket1557) is closed when the piston is closer to the hot end1221than Y0. The interior of the condenser1230may be at pressure PC. The interior of the expansion bladder1305may be at pressure PE0, which may be equal to or slightly higher than PATM. The pressure of the working fluid in the third pipe1263and the expansion tank1241may be maintained at pressure PTwhich may be well above PATM. The third valve1253may prevent the higher pressure fluid in the third pipe1263from flowing into the lower pressure first pipe1261. Fluid at pressure PTmay flow through the turbine140to the cold source1216. The cold source1216may be maintained at pressure PATMby a vent. A portion of fluid in the cold source1216may be bled off and routed to a cooling tower1270or a set of cooling towers. The fluid may be cooled to a temperature above the wet bulb temperature of the ambient air. The cooled fluid is sucked through the fourth pipe1264into the condenser1230by the lower pressure PC.

At block1603, operations of Stage 1 are performed. At Stage 1, the pressure sensor1560within the first valve1251may detect a pressure drop from PATMin the cross1570as the piston is forced down by expanding air. In some embodiments, the pressure in the cross1570at this stage in the cycle may be the same pressure as in the hot end1221. In some embodiments, the sensor may send the sensor data to the control box228. The control box228may control the fifth valve1255to then inject hot fluid from the hot reservoir212into the hot drum1250. The control box228may trigger the fifth valve1255to open for a specified amount of time. The control box228may then trigger the fifth valve1255to close so that a controlled (e.g., predetermined) amount of hot fluid is injected into the hot drum1250. The hot fluid may emit a vapor. In some embodiments, the vapor may be expanding. The expanding vapor emitted from the hot fluid may flow from the hot drum1250through the first valve1251and associated piping into the chamber1220. The piston may be pushed from the force of expanding air and vapor. The piston may exert force on the balloon1304. The pressure of the balloon1304may increase responsive to the force exerted by the piston. In some embodiments, the balloon1304may compress. The balloon1304may exert a force on the working fluid in the cold end1222of the chamber1220. As the piston moves and the balloon1304increases in pressure, the working fluid in the chamber1220and the first pipe1261may experience a pressure increase until the pressure of the working fluid reaches PT. The pressure increase experienced by the working fluid in the chamber1220and the first pipe1261may be in the form of a pressure surge.

At block1604, operations of Stage 2 are performed. At Stage 2, the piston may continue moving under its own momentum and under the force exerted by the expanding vapor in the hot end1221. The piston may push the balloon1304toward the cold end1222. The working fluid may be pushed through the first pipe1261and the third valve1253. The expansion tank1241may be sufficiently large compared to the addition of working fluid into the third pipe1263to maintain near constant pressure. In some embodiments, the constant pressure within the third pipe1263is PT. As the piston nears the end of its travel, it may reverse direction. The piston may decelerate rapidly as it nears the end of its travel. The rapid deceleration of the piston may cause a pressure surge to occur in the working fluid in the chamber1220and the first pipe1261.

At block1605, operations of Stage 3 are performed. At Stage 3, when the piston reaches the end of its travel, the pressure within the hot end1221, hot drum1250, and the associated piping may be PLPV. The sixth valve1256may be triggered to open. Hot fluid may flow from the hot drum1250through the sixth valve1256into the condenser1230. In the condenser1230, the fluid may be condensed to pressure PC. The pressure in the hot drum1250and the hot end1221may drop to PC.

At block1606, operations of Stage 4 are performed. At Stage 4, the piston may then be pushed back toward hot end1221by the balloon1304. In some embodiments, the compressed balloon exerts a force on the piston. As the piston travels, pressure in the hot end1221, the hot drum1250, and the condenser1230may be maintained at PC. Vapor may be pushed out of the hot end1221to the hot drum1250and the condenser1230.

The piston may continue to travel towards the hot end1221and may compress the air occupying the hot end1221. In some embodiments, the system1200may now be in Stage 5 at block1607. The pressure sensor1560in the first valve1251may detect a rise in pressure in the cross1570and may send the sensor data to the control box228. The control box228may trigger the fifth valve1255to open briefly. A small burst of hot fluid from the hot reservoir212may be injected into the hot drum1250. The hot fluid injected into the hot drum1250may cause the pressure inside the hot drum1250to rise above PLPVwhich may cause sixth valve1256to close. If the pressure in the hot end1221exceeds Patm, excess air may be pushed through the float valve (e.g., the combination of the float ball1559and the gasket1557) into the cross1570, through the outlet check valve1556, through the outlet ball valve1555. The excess air may be vented to atmosphere. Working fluid may fill the cold end1222responsive to the piston and the balloon1304traveling toward the hot end1221. In some embodiments, fluid may be sucked through the second pipe1262and the second valve1252into the first pipe1261. Only liquid may be allowed to pass through the second valve1252.

At block1608, operations of Stage 6 are performed. At stage 6, when the piston reaches its initial position Y0, the float valve (e.g., the combination of the float ball1559and gasket1557of the first valve1251) may close. Pressure in the hot end1221and the hot drum1250may be PATM. The piston may continue its travel under its own momentum. The piston may compress air in the hot end1221and the expansion bladder1305. The expansion bladder may compress responsive to the piston's travel. When the piston reaches the end of its travel, it may reverse direction. Fluid from the condenser1230may be sucked into the cold end1222before the piston changes direction.

At block1609, operations of Stage 7 are performed. In some embodiments, at Stage 7, the piston may begin to fall under its own weight. In some embodiments, the piston may be pushed by the force of expanding air at hot end1221. In some embodiments, the piston may be pushed by the force of the compressed expansion bladder1305. When the piston reaches its initial position Y0, the pressure in hot end1221may be PATM. As the piston falls, the pressure may fall below PATM. The pressure sensor1560may detect a pressure below PATM. The pressure sensor1560may send the sensor data to the control box228. The control box228may trigger the fifth valve1255to open. In some embodiments, flow may continue from block1609to block1603.

FIG.16Bis a flow diagram of a method1600B of converting energy (e.g., generating power), according to certain embodiments. The method1600B may be performed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, etc.), software (e.g., instructions run on a processor to perform hardware simulation), or a combination thereof. In one embodiment, the method1600B may be performed by control box228ofFIG.12. In one embodiment, the method1600B may be performed by control box228ofFIG.17. In one embodiment, the method1600B may be performed by a processing device of a control box of a heat engine. Alternatively, the method1600B can be performed by other components as described herein.

For simplicity of explanation, method1600B is depicted and described as a series of operations. However, operations in accordance with this disclosure can occur in various orders and/or concurrently and with other operations not presented and described herein. Furthermore, not all illustrated operations are performed to implement method1600B in accordance with the disclosed subject matter. In addition, those skilled in the art will understand and appreciate that method1600B could alternatively be represented as a series of interrelated states via a state diagram or events.

At block1611, the control box228receives, from a sensor, sensor data associated with a hybrid heat engine. In some embodiments, the sensor is a pressure sensor and the sensor data indicates a drop in pressure (e.g., in a chamber of the hybrid heat engine, in cross1570, etc.). In some embodiments, the pressure sensor is proximate to cross1570(seeFIG.15). In some embodiments, the pressure sensor monitors the pressure of the interior of the cross1570.

At block1612, the control box228causes, based on the sensor data, actuation of a valve (e.g., fifth valve1255) to provide first fluid (e.g., hot fluid, hot water, steam) from a heat source into a chamber of the hybrid heat engine. In some embodiments, the first fluid expands. The first fluid (e.g., expanding hot fluid) causes movement of a piston disposed within the chamber. The movement of the piston causes second fluid (e.g., working fluid) to be pushed through a turbine to generate energy. The turbine is fluidly coupled to the chamber via one or more first pipes.

In some embodiments, a partition (e.g., bladder structure) is disposed in the chamber between the piston (e.g., fluid piston) and the second fluid.

In some embodiments, the actuation of the valve in block1612causes a first amount of the first fluid to enter the chamber and the first amount of the first fluid causes the movement of the piston in a first direction away from the first amount of the first fluid. Subsequent to the movement of the piston in the first direction, the drop in pressure in the chamber causes opposite movement of the piston in a second direction opposite the first direction.

In some embodiments, the movement and opposite movement of the piston causes a cyclical flow of the second fluid through the one or more first pipes, the turbine, and one or more second pipes fluidly coupled between the turbine and the one or more first pipes.

In some embodiments, at block1612, the control box228causes the valve to open and to close (e.g., so that only a predetermined amount of hot fluid is injected). In some embodiments, the control box228determines the amount of hot fluid to be injected based on efficiency and power requirements. In some embodiments, the piston reverses direction at the end of movement of the piston.

In some embodiments, the control box228receives sensor data (e.g., pressure data from the pressure sensor located proximate to the cross1570, pressure data indicating a pressure rise, such as within the cross1570). In some embodiments, the control box228causes the valve to open (e.g., responsive to receiving the sensor data indicating a pressure rise). In some embodiments, the control box228causes the valve to close (e.g., after a short duration). The open valve may provide a burst of hot fluid to the chamber. In some embodiments, the burst of hot fluid may cause a pressure rise within the chamber. In some embodiments, the pressure rise within the chamber may cause a LPV (e.g., the sixth valve1256) to close. In some embodiments, flow may continue to block1611(e.g., flow is cyclic).

FIG.17is a schematic diagram illustrating a system1700to convert energy, according to certain embodiments. Elements inFIG.17that have a similar reference number as elements in other FIGS. (e.g.,FIGS.1A and12) may include similar features and/or similar functionality. System1700may be a hybrid heat engine that transforms a low-level temperature differential between a heat source and a heat sink into useful power. System1700may be a steam powered hydraulic ram (e.g., steam hydram).

System1700may be coupled to a heat source110(e.g., hot reservoir212), and a heat sink120(e.g., cold source1216, located proximate the output of the turbine140). System1700may include pipes including one or more of a first pipe1261, a second pipe1262, a third pipe1263, and a fourth pipe1264. System1700may include valves including one or more of a second valve1252, a third valve1253, a fourth valve1254, a fifth valve1255, a sixth valve1256, a seventh valve1257, and an eighth valve1258. (To maintain continuity with the numbering of system1200, system1700has no first valve). One or more of the valves of system1700may be controlled by the control box228. One or more valves of system1700may not be controlled by the control box228.

The chamber1220may contain a balloon. The balloon may be a partition. In some embodiments, the balloon is fluidly coupled to the hot drum1250by way of piping. In some embodiments, hot fluid may fill the balloon. The hot fluid may expand within the balloon. In some embodiments, the balloon may be compressible. In some embodiments, the balloon may expand responsive to the actuation of the fifth valve1255. In some embodiments, the balloon may compress responsive to the movement of the piston. The balloon may be made of a polymer. In some embodiments, the balloon is made of butyl rubber. The balloon may be a bladder. The balloon may exert pressure on the piston. In some embodiments, the balloon may push the piston towards the cold end1222as the balloon expands.

The chamber1220may contain a pocket of gas. In some embodiments, the pocket of gas may be a pocket of air. The pocket of gas may be contained in the cold end1222. The pocket of gas may compress responsive to the movement of the piston and the balloon. The pocket of gas may exert a force upon the working fluid in the first pipe responsive to the compression of the pocket of gas.

The fifth valve1255may be configured to open at controlled intervals. The control box228may control the intervals at which the fifth valve1255opens. Hot fluid may flow into the balloon at the hot end1221of the chamber1220when the fifth valve1255is open. Hot fluid may flow out of the balloon at the hot end1221of the chamber1220when the sixth valve1256is open responsive to the movement of the piston. Hot fluid from the heat source110may expand within the balloon. The expanding hot fluid may exert a force on the piston within the chamber1220.

The chamber1220may be fluidly coupled to the first pipe1261. The first pipe1261may be fluidly coupled to the condenser1230. The first pipe1261may receive working fluid from the condenser1230. The working fluid in the first pipe1261may be pushed by the pocket of air within the chamber1220responsive to the flow of hot fluid into the balloon in the hot end1221of the chamber1220. In some embodiments, the hot fluid may push the piston which may push the working fluid. The pressure of the working fluid may be raised when pushed on by the piston. The working fluid may be prevented from flowing back to the condenser1230by the seventh valve1257. The seventh valve1257may be a check valve.

Expended heat source fluid from the chamber1220may be routed to the condenser1230through, the hot drum1250, the sixth valve1256, and associated piping. The sixth valve1256may be a solenoid drain valve (e.g., SDV1800ofFIG.18). In some embodiments, the sixth valve1256may be a low pressure valve (LPV).

FIG.18is a schematic diagram illustrating a solenoid drain valve (SDV)1800, according to certain embodiments. In some embodiments, the sixth valve1256is a SDV1800. For example, the sixth valve1256ofFIG.12or ofFIG.17that allows hot water that has cooled to drain from the lower portion of the hot drum1250to the condenser1230may be an SDV1800. An SDV1800may actuate responsive to a signal from the control box228. The SDV1800may be used in heat engines (e.g., one or more of system100, system200, system300, system700, system1200, or system1700).

The SDV1800may include one or more of a lower slug1801, an upper slug1802, a rod1811, a spring1812, a ball1813, a solenoid1821, a lower gasket1831, an upper gasket1832, a valve body1840, and multiple sealing surfaces configured to seal ports or passages.

The lower slug1801and the upper slug1802may be cylindrical in shape. In some embodiments, the lower slug1801and the upper slug1802may be made of similar materials. In some embodiments, one or both of the lower slug1801and the upper slug1802are made of steel. In some embodiments, one or both of the lower slug1801and the upper slug1802are made of galvanized steel. The upper slug1802may be secured to the valve body1840with a fastener. In some embodiments, the upper slug1802is secured with a pin. The upper slug1802may have a hollow core configured to receive the rod1811and the spring1812. The lower slug1801may slide freely within the valve body1840. The lower slug1801may be prevented from passing a point in the valve body by a stop. The stop may be non-magnetic. The stop may be made of stainless steel. The stop may be made of rubber. In some embodiments, the stop is the lower gasket1831. The lower gasket1831may be an O-ring.

The rod1811may pass through the hollow core of the upper slug1802. In some embodiments, the rod1811may be able to slide freely through the hollow core of the upper slug1802. A distal end of the rod1811may be attached to a spring. In some embodiments, the spring is cylindrical. In some embodiments, the spring is attached to the lower slug1801. In some embodiments, the spring is spring1812. The rod1811may protrude from an end of the upper slug1802when the SDV1800is closed. The rod1811may be made of a non-magnetic material. In some embodiments, the rod1811is made of acetal plastic (e.g., polyacetal and polyoxymethylene (POM)), a semi-crystalline engineered thermoplastic, etc.).

The ball1813may be attached to a distal end of the rod1811. The ball1813may be attached to the rod1811by a fastener. In some embodiments, the ball1813may be threaded onto the rod1811. The ball1813may be made of rubber. The ball1813may seat against the upper gasket1832to form a seal. The upper gasket1832may form a sealing surface. The upper gasket may be made of rubber. The upper gasket1832may be an O-ring. The ball1813and the rod1811may move together in relation to the valve body1840.

Responsive to a signal, the solenoid1821may become energized. When the solenoid1821becomes energized, the lower slug1801may become magnetized. The lower slug1801may move toward the upper slug1802responsive to becoming magnetized. The lower slug1801may move responsive to magnetic force. As the lower slug1801rises, the spring1812may compress and exert a force upon the rod1811. The rod1811may move responsive to the force exerted by the spring1812. The rod1811may push the ball1813off a sealing surface, opening the valve and allowing fluid to pass. Responsive to a signal, the solenoid1821may become de-energized and the valve may close.

FIG.19is a schematic diagram illustrating a reverse float valve1900, according to certain embodiments. The reverse float valve1900may include one or more of a reverse float ball1901, a reverse float gasket1902, and a reverse float body1903. The reverse float ball1901may be hollow. In some embodiments, the reverse float ball1901may be made of metal. In other embodiments, the reverse float ball1901may be made of polypropylene plastic. The reverse float ball1901may seat against the reverse float gasket1902in the absence of liquid within the reverse float body1903. The reverse float gasket1902may be made of rubber. In some embodiments, the reverse float gasket1902is an O-ring. When seated against the reverse float gasket1902, the reverse float ball1901may cover a port. The reverse float ball1901may float on liquid present within the reverse float body1903. The reverse float valve1900may be configured to allow the passage of liquid. The reverse float valve1900may be configured to prevent the passage of gas.

When the reverse float body1903fills with liquid, the reverse float ball1901may float on the liquid. When the reverse float ball1901floats on the liquid within the reverse float body1903, the float ball1901may become unseated from the reverse float gasket1902and the liquid may drain from the reverse float body. When enough liquid drains from the reverse float body1903to no longer provide sufficient buoyancy, the reverse float ball1901may seat against the reverse float gasket1902. The seating of the reverse float ball1901against the reverse float gasket1902may prevent the passage of gas through the reverse float valve1900. In the above description, numerous details are set forth. It will be apparent, however, to one of ordinary skill in the art having the benefit of this disclosure, that embodiments may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the description.

Some portions of the detailed description are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of steps leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the above discussion, it is appreciated that throughout the description, discussions utilizing terms such as “determining,” “controlling,” “providing,” “maintaining,” “generating,” or the like, refer to the actions and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (e.g., electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

Embodiments also relate to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may include a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions.

The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct a more specialized apparatus to perform the required method steps. The required structure for a variety of these systems will appear from the description below. In addition, the present embodiments are not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the present disclosure. It should also be noted that the terms “when” or the phrase “in response to,” as used herein, should be understood to indicate that there may be intervening time, intervening events, or both before the identified operation is performed.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the present embodiments should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.