Circulating power generation system compositely driven by ocean temperature difference energy and geothermal energy
By introducing a series structure of thermal storage container and evaporator into the ocean thermal energy conversion system, and using warm seawater and geothermal water to heat the working fluid in stages, the problem of low power generation efficiency of ocean thermal energy conversion has been solved, and higher power generation efficiency has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SOUTHERN MARINE SCIENCE & ENGINEERING GUANGDONG LABORATORY (ZHANJIANG)
- Filing Date
- 2025-06-30
- Publication Date
- 2026-05-01
AI Technical Summary
Existing ocean thermal energy conversion systems suffer from low overall thermal efficiency and power generation efficiency due to insufficient seawater temperature difference, resulting in low heat source temperature.
A combined ocean thermal energy and geothermal energy-driven circulating power generation system is used. By setting up a series structure of evaporator and thermal storage container in the circulating power generation path, the initial liquid working fluid is first heated by warm seawater, and then the gaseous working fluid is further heated by high-temperature geothermal water to increase its enthalpy level.
This improves the thermal energy quality of the gaseous working fluid before it enters the expander, increases the mechanical output power, and thus improves the power generation efficiency of ocean thermal energy conversion.
Smart Images
Figure CN224187703U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of ocean thermal energy conversion technology, and in particular to a combined ocean thermal energy conversion and geothermal energy driven cycle power generation system. Background Technology
[0002] Ocean thermal energy (OTEC) utilizes the thermal energy resources generated by the temperature difference between seawater at different depths. Typically, surface seawater is warmer than deep seawater. By establishing a thermodynamic cycle between the warm surface seawater and the cold seawater, the expansion of a working fluid can be driven to generate electricity. This power generation method has advantages such as being renewable and having zero emissions, making it particularly suitable for tropical and subtropical deep-water areas. Currently, most common OTEC power generation systems employ a subcritical organic Rankine cycle structure. This involves using a low-boiling-point working fluid to absorb heat from surface seawater in an evaporator and vaporize it. The vaporized working fluid then drives a generator through an expander to output electricity. The fluid is then condensed in a condenser using cold deep seawater and pumped back to the evaporator, forming a closed loop. However, because the seawater temperature difference is generally less than 20°C, the heat source temperature is low, resulting in low overall system thermal efficiency and poor power generation efficiency. Therefore, improving the power generation efficiency based on OTEC has become an urgent technical problem to be solved. Utility Model Content
[0003] This application provides a combined ocean thermal energy and geothermal energy driven cycle power generation system to improve the power generation efficiency based on ocean thermal energy.
[0004] To achieve the above objectives, this application provides a combined ocean thermal energy and geothermal energy driven circular power generation system, the system including a circular power generation path and a heat source supply component;
[0005] The circulating power generation path includes: an evaporator, a heat storage container, a generator, and an expander. The evaporator, the heat storage container, and the expander are connected in series. The evaporator is also connected to the heat source supply component. The heat storage container stores geothermal water.
[0006] The evaporator is used to heat the initial liquid working fluid with warm seawater provided by the heat source supply component to obtain a gaseous working fluid.
[0007] The heat storage container is used to heat the gaseous working fluid with the geothermal water to obtain a heated gaseous working fluid, wherein the temperature of the geothermal water is higher than the temperature of the gaseous working fluid.
[0008] The expander is used to transfer the heated gaseous working fluid to the generator for power generation.
[0009] In one embodiment, the circulating power generation path further includes: a condenser and a working fluid pump;
[0010] The condenser is connected to the expander and the working fluid pump respectively, and the working fluid pump is also connected to the evaporator;
[0011] The generator is used to transmit the gaseous working fluid after it has done work to the expander. The gaseous working fluid after it has done work is the gaseous working fluid obtained by the generator after it generates electricity using the heated gaseous working fluid.
[0012] The expander is used to transfer the gaseous working fluid after work to the condenser;
[0013] The condenser is used to condense the gaseous working fluid after work is done to obtain the initial liquid working fluid, and the initial liquid working fluid is transferred to the evaporator by the working fluid pump.
[0014] In one embodiment, the system further includes a cold source supply component connected to the condenser;
[0015] The condenser is used to condense the gaseous working fluid after it has done work using cold seawater supplied by the cold source supply component.
[0016] In one embodiment, the circulating power generation path consists of at least two sets.
[0017] In one embodiment, the evaporator of the previous set of circulating power generation paths is connected to the evaporator of the next set of circulating power generation paths through the warm seawater supply pipe in the heat source supply assembly.
[0018] The evaporator of the previous set of circulating power generation paths is used to heat the initial liquid working fluid in the previous set of circulating power generation paths using the warm seawater, and then transmits it to the evaporator of the next set of circulating power generation paths through the warm seawater supply pipe.
[0019] The evaporator in the next cycle power generation path is used to heat the initial liquid working fluid in the next cycle power generation path with warm seawater that has been heated by the initial liquid working fluid in the previous cycle power generation path.
[0020] In one embodiment, the condenser in the previous set of circulating power generation paths is connected to the condenser in the next set of circulating power generation paths;
[0021] The condenser in the previous set of circulating power generation paths is used to condense the gaseous working fluid after work is done in the previous set of circulating power generation paths using the cold seawater, and to transfer the condensed cold seawater to the condenser in the next set of circulating power generation paths.
[0022] The condenser in the next set of circulating power generation paths is used to condense the gaseous working fluid that has done work in the next set of circulating power generation paths using the condensed cold seawater.
[0023] In one embodiment, the cold source supply component includes a cold seawater booster pump and a cold seawater supply pipeline;
[0024] The cold seawater booster pump is connected to the cold seawater supply pipeline, and the condenser in the last set of circulating power generation paths is connected to the cold seawater supply pipeline. The cold seawater booster pump is also connected to the target ocean and the condenser in the first set of circulating power generation paths.
[0025] The cold seawater booster pump is used to transfer cold seawater from the target ocean to the condenser in the first set of circulating power generation paths;
[0026] The cold seawater booster pump is also used to receive cold seawater from the condenser in the last set of circulating power generation paths through the cold seawater supply pipeline, and to output the cold seawater from the condenser in the last set of circulating power generation paths to the target ocean.
[0027] In one embodiment, the warm seawater supply pipe is a corrosion-resistant pipe and is equipped with a one-way connection structure.
[0028] In one embodiment, the initial liquid working fluid is the same in each of the circulating power generation paths.
[0029] In one embodiment, the evaporator is a shell-and-tube heat exchanger.
[0030] This application provides a combined ocean thermal energy conversion and geothermal energy driven circular power generation system. The system includes a circular power generation path and a heat source supply component. The circular power generation path includes an evaporator, a thermal storage container, a generator, and an expander. The evaporator, thermal storage container, and expander are connected in series. The evaporator is also connected to the heat source supply component. The thermal storage container stores geothermal water. The evaporator is used to heat the initial liquid working fluid using warm seawater provided by the heat source supply component to obtain a gaseous working fluid. The thermal storage container is used to heat the gaseous working fluid using geothermal water to obtain a heated gaseous working fluid. The temperature of the geothermal water is higher than the temperature of the gaseous working fluid. The expander is used to transfer the heated gaseous working fluid to the generator for power generation. This application incorporates a series structure of an evaporator and a thermal storage container in the circulating power generation path. First, warm seawater supplied by the heat source supply component is used to heat the initial liquid working fluid in the first stage, causing it to vaporize. Then, high-temperature geothermal water stored in the thermal storage container is used to further heat the gaseous working fluid, increasing its enthalpy level. This improves the thermal energy quality of the gaseous working fluid before it enters the expander. During the process of the gaseous working fluid entering the expander to drive the generator and generate electricity, the higher initial thermal energy state increases the overall mechanical output power, thereby improving the power generation efficiency based on ocean thermal energy. Attached Figure Description
[0031] Figure 1This is a schematic diagram of the first embodiment of the combined ocean thermal energy and geothermal energy driven cycle power generation system of this application;
[0032] Figure 2 This is a schematic diagram of an embodiment of the combined ocean thermal energy and geothermal energy driven cycle power generation system of this application;
[0033] Figure 3 This is a flowchart illustrating an embodiment of the combined ocean thermal energy and geothermal energy driven cycle power generation system of this application.
[0034] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0035] It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application.
[0036] It's important to note that ocean thermal energy (OTEC) utilizes the thermal energy generated by the temperature difference between seawater at different depths. Typically, surface seawater is warmer, while deep seawater is cooler. By establishing a thermodynamic cycle between the warm surface seawater and the cold seawater, the working fluid expands, generating electricity. This method offers advantages such as renewability and zero emissions, making it particularly suitable for tropical and subtropical deep-water areas. Currently, most common OTEC power generation systems employ a subcritical organic Rankine cycle structure. This involves a low-boiling-point working fluid absorbing heat from surface seawater in an evaporator and vaporizing. The vaporized fluid then powers a generator via an expander, producing electricity. The condensate is then cooled by deep seawater in a condenser and pumped back to the evaporator, forming a closed loop. However, because the seawater temperature difference is generally less than 20°C, the heat source temperature is low, resulting in low overall system thermal efficiency and poor power generation efficiency. Therefore, improving the power generation efficiency based on OTEC has become a pressing technical challenge.
[0037] The main solution of this application is to provide a combined ocean thermal energy differential and geothermal energy driven circular power generation system. The system includes a circular power generation path and a heat source supply component. The circular power generation path includes an evaporator, a thermal storage container, a generator, and an expander. The evaporator, thermal storage container, and expander are connected in series. The evaporator is also connected to the heat source supply component. The thermal storage container stores geothermal water. The evaporator is used to heat the initial liquid working fluid with the warm seawater provided by the heat source supply component to obtain a gaseous working fluid. The thermal storage container is used to heat the gaseous working fluid with the geothermal water to obtain a heated gaseous working fluid. The temperature of the geothermal water is higher than the temperature of the gaseous working fluid. The expander is used to transfer the heated gaseous working fluid to the generator for power generation.
[0038] This application incorporates a series structure of an evaporator and a thermal storage container in the circulating power generation path. First, warm seawater supplied by the heat source supply component is used to heat the initial liquid working fluid in the first stage, causing it to vaporize. Then, high-temperature geothermal water stored in the thermal storage container is used to further heat the gaseous working fluid, increasing its enthalpy level. This improves the thermal energy quality of the gaseous working fluid before it enters the expander. During the process of the gaseous working fluid entering the expander to drive the generator and generate electricity, the higher initial thermal energy state increases the overall mechanical output power, thereby improving the power generation efficiency based on ocean thermal energy.
[0039] Reference Figure 1 , Figure 1 This is a schematic diagram of the first embodiment of the combined ocean thermal energy and geothermal energy driven cycle power generation system of this application.
[0040] The system includes a circulating power generation path and a heat source supply component; the circulating power generation path includes an evaporator (i.e., Figure 1 The first evaporator), the heat storage container (i.e.) Figure 1 The first thermal storage container), generator (i.e.) Figure 1 The first generator and expander (i.e.) Figure 1 The system consists of an evaporator, a heat storage container, and an expander connected in series. The evaporator is also connected to a heat source supply component. The heat storage container stores geothermal water. The evaporator is used to heat the initial liquid working fluid using warm seawater provided by the heat source supply component to obtain a gaseous working fluid. The heat storage container is used to heat the gaseous working fluid using geothermal water to obtain a heated gaseous working fluid. The temperature of the geothermal water is higher than the temperature of the gaseous working fluid. The expander is used to transfer the heated gaseous working fluid to the generator for power generation.
[0041] It should be noted that the circulating power generation path refers to the complete process path of the working fluid in a closed loop, undergoing evaporation, heating, expansion and work performance, condensation, and recirculation, used to convert thermal energy into electrical energy. An evaporator is a device that uses an external heat source (such as warm seawater) to heat the initial liquid working fluid to a vaporized state. A geothermal storage container is a device used to store geothermal water and transfer geothermal energy to the gaseous working fluid through a heat exchange structure. An expander is a device that converts the thermal energy of a high-temperature, high-pressure gaseous working fluid into mechanical energy. The heat source supply component is a structure that provides the heat source for the evaporator. The initial liquid working fluid refers to the working fluid in the initial or condensed state of the system; it is a pre-selected organic working fluid with thermodynamic characteristics such as a low boiling point and high heat capacity ratio, and its temperature is lower than that of warm seawater. The gaseous working fluid refers to the gaseous working fluid formed after heating and evaporation in the evaporator.
[0042] Specifically, the system first introduces warm seawater into the evaporator via a heat source supply component. The evaporator uses the heat from the warm seawater to heat the initial liquid working fluid in the circulation path, causing it to undergo a phase change and transform into a low-pressure gaseous working fluid. Subsequently, this gaseous working fluid is transported to a thermal storage container, where it exchanges heat with geothermal water at a higher temperature, further raising its temperature and achieving a higher enthalpy (energy level), providing a greater energy difference for subsequent work processes. The heated high-temperature gaseous working fluid is then introduced into an expander. In the expander, the working fluid expands and performs work, driving the expander's rotor to rotate. The expander's rotating shaft is mechanically connected to a generator, thereby driving the generator to operate and output electrical energy.
[0043] This step achieves graded heat utilization of two different heat sources (warm seawater and geothermal water) by setting up a series connection between the evaporator and the thermal storage container. First, the evaporator uses warm seawater to preheat the working fluid, avoiding energy waste caused by directly using geothermal energy. Then, the thermal storage container introduces geothermal water for high-temperature supplementary heating, significantly increasing the enthalpy of the working fluid and effectively enhancing its expansion and work-producing capacity. The entire process forms a stepped heat input path from a low-grade heat source to a high-grade heat source, thereby improving the efficiency of converting thermal energy into mechanical and electrical energy, achieving the goal of high-efficiency power generation based on ocean thermal energy differentials.
[0044] This embodiment provides a combined ocean thermal energy differential and geothermal energy driven circular power generation system. The system includes a circular power generation path and a heat source supply component. The circular power generation path includes an evaporator, a thermal storage container, a generator, and an expander. The evaporator, thermal storage container, and expander are connected in series. The evaporator is also connected to the heat source supply component. The thermal storage container stores geothermal water. The evaporator is used to heat the initial liquid working fluid using warm seawater provided by the heat source supply component to obtain a gaseous working fluid. The thermal storage container is used to heat the gaseous working fluid using geothermal water to obtain a heated gaseous working fluid. The temperature of the geothermal water is higher than the temperature of the gaseous working fluid. The expander is used to transfer the heated gaseous working fluid to the generator for power generation. This embodiment sets up a series structure of an evaporator and a thermal storage container in the circulating power generation path. First, the warm seawater provided by the heat source supply component is used to heat the initial liquid working fluid in the first stage, causing the working fluid to vaporize. Then, the high-temperature geothermal water stored in the thermal storage container is used to further heat the gaseous working fluid, increasing its enthalpy level. This improves the thermal energy quality of the gaseous working fluid before it enters the expander. During the process of the gaseous working fluid entering the expander to do work and drive the generator to generate electricity, the higher initial thermal energy state increases the overall mechanical output power, thereby improving the power generation efficiency based on ocean thermal energy difference.
[0045] Based on the first embodiment described above, in one embodiment, the circulating power generation path further includes: a condenser (i.e., Figure 1 The first condenser) and the working fluid pump (i.e. Figure 1The system comprises: a first working fluid pump; a condenser connected to both the expander and the working fluid pump, and the working fluid pump also connected to the evaporator; a generator used to transfer the gaseous working fluid after work to the expander, wherein the gaseous working fluid after work is obtained by the generator using the heated gaseous working fluid to generate electricity; the expander used to transfer the gaseous working fluid after work to the condenser; and the condenser used to condense the gaseous working fluid after work to obtain the initial liquid working fluid, and to transfer the initial liquid working fluid to the evaporator via the working fluid pump.
[0046] It should be noted that a condenser is a device used to cool a gaseous working fluid and condense it into a liquid state. A working fluid pump is a device that pressurizes the condensed liquid working fluid and delivers it to an evaporator. The gaseous working fluid after work is the gaseous working fluid that has expanded and done work, releasing its energy.
[0047] Specifically, a mechanical coupling relationship is established between the generator and the expander. After the generator completes the power generation process by releasing energy from the high-temperature, high-pressure gaseous working fluid, it introduces the gaseous working fluid that has done work into the expander. Inside the expander, the gaseous working fluid further releases some energy and completes the final work, after which it is transported to the condenser.
[0048] Furthermore, the gaseous working fluid entering the condenser is cooled through heat exchange with an external cold source (such as cold seawater), completing a gas-liquid phase change and transforming into a liquid initial working fluid. Subsequently, the working fluid pump starts operating, pressurizing the liquid working fluid and transporting it back to the evaporator, realizing a complete closed-loop cycle and providing the material basis for the next round of power generation.
[0049] This step constructs a complete closed-loop thermodynamic cycle system by adding a condenser and a working fluid pump to the circulation path. The condenser enables effective recovery of the working fluid from gaseous to liquid state, preventing energy loss and media waste; the working fluid pump maintains the pressure and stability of the fluid circulation within the system, allowing the working fluid to continuously flow back to the evaporator for the next round of heating and power generation. Through the design of this circulation structure, the acquisition of thermal energy, the output of mechanical energy, the generation of electrical energy, and the recovery of the working fluid form a highly efficient closed loop, effectively improving the overall thermal efficiency and continuous power generation capability of the system.
[0050] Based on the first embodiment described above, in one embodiment, the system further includes a cold source supply component connected to the condenser; the condenser is used to condense the gaseous working fluid after work is performed using cold seawater provided by the cold source supply component.
[0051] It should be noted that the cold source supply component refers to the device that provides a low-temperature cooling medium (such as cold seawater) for cooling and condensation. The gaseous working fluid after work is the gaseous working fluid that has undergone energy release and temperature and pressure reduction after passing through an expander or generator.
[0052] Specifically, the cold source supply component draws cold seawater from the target sea area and transports it to the condenser through pipelines. A booster pump within the cold source supply component ensures sufficient flow rate and pressure of the cold seawater for stable cooling. When the gaseous working fluid, having performed work, enters the condenser, it exchanges heat with the cold seawater from the cold source supply component. Through this heat exchange, the heat of the gaseous working fluid is rapidly carried away, causing condensation and conversion into an initial liquid working fluid, preparing for evaporator heating in the subsequent cycle.
[0053] By installing a cold source supply component and connecting it to the condenser, the condenser can continuously and stably obtain cooling medium, improving the condensation rate and efficiency of the gaseous working fluid after work is performed. The cold seawater provided by the cold source supply component has the characteristics of low temperature and high flow rate, which helps to enhance the heat exchange process, quickly complete the phase change recovery of the working fluid, reduce circulation resistance and energy consumption, thereby ensuring the thermal efficiency and continuous operation capability of the circulating power generation system, and providing a key guarantee for the closed-loop operation of the system.
[0054] Please see Figure 2 , Figure 2 This is a schematic diagram of an embodiment of the combined ocean thermal energy and geothermal energy driven circulating power generation system of this application. Based on the first embodiment described above, in one embodiment, the circulating power generation path comprises at least two sets. The evaporator of the previous set of circulating power generation paths is connected to the evaporator of the next set of circulating power generation paths via a warm seawater supply pipe in the heat source supply assembly; the evaporator of the previous set of circulating power generation paths is used to heat the initial liquid working fluid in the previous set of circulating power generation paths using the warm seawater, and then transmits the heat to the evaporator of the next set of circulating power generation paths via the warm seawater supply pipe; the evaporator of the next set of circulating power generation paths is used to heat the initial liquid working fluid in the next set of circulating power generation paths using the warm seawater heated from the initial liquid working fluid in the previous set of circulating power generation paths.
[0055] It should be noted that the "upper group" and "next group" of circulating power generation paths represent multiple groups of circulating paths sequentially deployed in the system. The "upper group" receives warm seawater first, and the "next group" receives warm seawater after heat transfer, reflecting a temperature gradient utilization strategy. This embodiment uses two groups for illustration, denoted as the first circulating path and the second circulating path, respectively. The upper group of circulating power generation paths is denoted as the first circulating path, and the next group is denoted as the second circulating path. The evaporator, heat storage container, expander, condenser, working fluid pump, and generator in the upper group of circulating power generation paths are all located in... Figure 2 The term "first" is used in the description. In the next cycle of power generation, the evaporator, thermal storage container, expander, condenser, working fluid pump, and generator are all located in... Figure 2 The term "second" is used in the explanation.
[0056] Specifically, the system has at least two sets of circulating power generation paths, each equipped with independent evaporators, thermal storage containers, expanders, and other components. In the first circulating path, the evaporator is initially connected to a warm seawater booster pump, receiving high-temperature warm seawater for heat exchange with its initial liquid working fluid. The heated warm seawater is not directly discharged but guided through a warm seawater supply pipe to the evaporator in the next circulating path for continued use. The evaporator in the next circulating path receives warm seawater from the first path; although some of its heat has been transferred to the working fluid in the first path, it still retains usable calorific value. This evaporator utilizes the remaining heat to continue heating the initial liquid working fluid within its own path, thus achieving cascade utilization of thermal energy.
[0057] By setting up multiple sets of circulating power generation paths and using evaporators in series to utilize warm seawater in a tiered manner, the efficiency of ocean thermal energy conversion can be maximized while maintaining a compact structure. The previous set of evaporators preferentially absorbs heat for efficient heating, while subsequent sets of evaporators continue to utilize residual calorific value, forming an energy gradient transfer path. This design not only improves the overall heat exchange efficiency of ocean thermal energy conversion but also reduces energy loss, thereby achieving the goal of improving overall power generation efficiency through system structure improvements.
[0058] In one embodiment, the condenser in the previous set of circulating power generation paths is connected to the condenser in the next set of circulating power generation paths; the condenser in the previous set of circulating power generation paths is used to condense the gaseous working fluid after work has been done in the previous set of circulating power generation paths using the cold seawater, and to transfer the condensed cold seawater to the condenser in the next set of circulating power generation paths; the condenser in the next set of circulating power generation paths is used to condense the gaseous working fluid after work has been done in the next set of circulating power generation paths using the condensed cold seawater.
[0059] Specifically, the cold seawater in the system is supplied by the cold source supply component to the condenser of the previous circulation path. This condenser cools the gaseous working fluid from the previous expander after it has performed work, condensing it into a liquid working fluid for subsequent process cycles. During this process, the cold seawater absorbs heat and its temperature rises, but it does not completely lose its cooling capacity. The condensed cold seawater is not directly discharged from the system but is guided to the condenser of the next circulation path to continue cooling the gaseous working fluid in the next cycle. Although the temperature rises, the condensed cold seawater can still meet the heat exchange requirements, thus playing a secondary cooling role.
[0060] By setting up multiple sets of condensers and realizing the cascaded flow of cold seawater, where each condenser uses the original cold seawater to cool the working medium and then uses the condensed cold seawater for the next condenser, the cooling medium is utilized in stages. This structure significantly improves the utilization efficiency of cold seawater, reduces the overall cold source consumption demand, avoids cold source waste, and enhances the system's energy utilization rate, thereby indirectly promoting the stable operation and energy efficiency improvement of the circulating power generation system.
[0061] Based on the first embodiment described above, in one embodiment, the cold source supply component includes a cold seawater booster pump and a cold seawater supply pipeline; the cold seawater booster pump is connected to the cold seawater supply pipeline, and the condenser in the last set of circulating power generation paths is connected to the cold seawater supply pipeline; the cold seawater booster pump is also connected to the target ocean and the condenser in the first set of circulating power generation paths; the cold seawater booster pump is used to transfer cold seawater from the target ocean to the condenser in the first set of circulating power generation paths; the cold seawater booster pump is also used to receive cold seawater from the condenser in the last set of circulating power generation paths through the cold seawater supply pipeline, and output the cold seawater from the condenser in the last set of circulating power generation paths to the target ocean.
[0062] It should be noted that a cold seawater booster pump is a device used to extract cold seawater from the ocean and provide sufficient head and flow rate to deliver it to the various condensers within the system. The cold seawater supply pipeline connects the cold seawater booster pump to each condenser and is used to transport the cold seawater. The target ocean refers to the sea area on which the system operates, providing cold seawater resources.
[0063] Specifically, the cold seawater booster pump draws cold seawater from the target ocean and sends it through a cold seawater supply pipeline to the condensers in the first set of circulating power generation paths. This cools the gaseous working fluid after it has performed work, causing it to condense into an initial liquid working fluid. As the cold seawater flows sequentially through each set of condensers, its temperature gradually increases, but effective heat exchange is still achieved. After the cold seawater has completed its cooling task in the condensers of the last set of circulating paths, it flows back to the cold seawater booster pump through a pipeline, from which it is discharged into the target ocean, achieving closed-loop supply and discharge management. This method not only completes multi-stage cooling but also centrally manages the discharge of the cooling medium, ensuring efficient system operation.
[0064] This structure forms a closed-loop cooling cycle through a cold seawater booster pump and cold seawater supply pipeline. This not only efficiently delivers low-temperature seawater to each condenser group but also enables multi-stage utilization of the cold seawater through series-connected condensers, thereby improving the efficiency of cooling resource utilization. Furthermore, the centralized return of condensed water to the ocean simplifies the management of the cooling medium's inlet and outlet, helps maintain system thermal balance, enhances the system's continuous and stable operation, and improves the overall power generation efficiency based on ocean thermal energy conversion.
[0065] Based on the first embodiment described above, in one embodiment, the warm seawater supply pipe is a corrosion-resistant pipe and has a unidirectional connection structure. The initial liquid working fluid in each circulating power generation path is of the same type. The evaporator is a shell-and-tube heat exchanger.
[0066] It should be noted that corrosion-resistant pipes refer to pipe materials capable of resisting seawater corrosion. A unidirectional connection structure refers to a pipe connection structure that allows fluid to flow in only one direction. The initial liquid working fluid is a low-boiling-point working fluid (such as R245fa, fluorocarbons, etc.), and its initial state is liquid. A shell-and-tube heat exchanger is a heat exchange device with a shell and internal tube bundle structure. Different fluids flow through the shell-side and tube-side channels respectively to achieve heat exchange.
[0067] Specifically, in this system, all evaporators adopt a shell-and-tube heat exchanger structure. Warm seawater flows through the tube-side channels, serving as the heat source fluid to exchange heat with the initial liquid working fluid in the shell-side channels, heating it into a gaseous state. The evaporators are connected in series via warm seawater supply pipes. Each warm seawater supply pipe is a corrosion-resistant pipe with a unidirectional connection structure, ensuring that the warm seawater flows sequentially through multiple sets of evaporators in a predetermined direction, avoiding backflow or disturbance. In addition, multiple circulating power generation paths in the system use the same type of working fluid, which helps simplify control strategies, maintenance management, and thermodynamic performance matching, ensuring coordinated operation of each path under uniform temperature difference conditions.
[0068] By employing a shell-and-tube heat exchanger structure, the evaporator achieves excellent heat exchange efficiency and high structural stability, adapting to complex marine environments. Combined with corrosion-resistant warm seawater supply pipes and a unidirectional connection structure, seawater corrosion and backflow interference are avoided, enhancing the system's operational stability and reliability. Furthermore, using the same type of working fluid in all pathways not only facilitates synchronized control of circulation characteristics but also reduces material procurement and maintenance costs, thereby improving the overall power generation efficiency and engineering feasibility of the system driven by a combination of ocean thermal energy and geothermal energy.
[0069] This embodiment provides a combined ocean thermal energy differential and geothermal energy driven circular power generation system. The system includes a circular power generation path and a heat source supply component. The circular power generation path includes an evaporator, a thermal storage container, a generator, and an expander. The evaporator, thermal storage container, and expander are connected in series. The evaporator is also connected to the heat source supply component. The thermal storage container stores geothermal water. The evaporator is used to heat the initial liquid working fluid using warm seawater provided by the heat source supply component to obtain a gaseous working fluid. The thermal storage container is used to heat the gaseous working fluid using geothermal water to obtain a heated gaseous working fluid. The temperature of the geothermal water is higher than the temperature of the gaseous working fluid. The expander is used to transfer the heated gaseous working fluid to the generator for power generation. This embodiment sets up a series structure of an evaporator and a thermal storage container in the circulating power generation path. First, the warm seawater provided by the heat source supply component is used to heat the initial liquid working fluid in the first stage, causing the working fluid to vaporize. Then, the high-temperature geothermal water stored in the thermal storage container is used to further heat the gaseous working fluid, increasing its enthalpy level. This improves the thermal energy quality of the gaseous working fluid before it enters the expander. During the process of the gaseous working fluid entering the expander to do work and drive the generator to generate electricity, the higher initial thermal energy state increases the overall mechanical output power, thereby improving the power generation efficiency based on ocean thermal energy difference.
[0070] For example, please refer to Figure 3 , Figure 3 This is a flowchart illustrating an embodiment of the combined ocean thermal energy and geothermal energy driven cycle power generation system of this application.
[0071] like Figure 2 As shown, surface warm seawater (state point 1) is pumped to evaporator 1 (state point 2) by a warm seawater pump, where it exchanges heat with the working fluid (state point 3). The working fluid, heated to a gaseous state (state point 4), enters geothermal energy storage tank 1, where its temperature is further increased (state point 5) before entering expander 1. Its internal energy is converted into mechanical energy, which is then converted into electrical energy by generator 1 connected to expander 1. The exhaust steam from expander 1 enters condenser 1 (state point 6), condenses into liquid, and is pressurized by working fluid pump 1 (state point 7). It then enters evaporator 1, completing the cycle.
[0072] Seawater from the outlet of evaporator 1 enters evaporator 2 (state point 8), exchanges heat with the working fluid in the second-stage cycle (state point 10), and is then discharged (state point 9). The working fluid, heated to a gaseous state (state point 11), enters geothermal energy storage tank 2, where its temperature is further increased (state point 12) before entering expander 2. Its internal energy is converted into mechanical energy, which is then converted into electrical energy by generator 2 connected to expander 2. The exhaust steam from the outlet of expander 2 enters condenser 2 (state point 13), condenses into liquid, and is pressurized by working fluid pump 1 (state point 14) before entering evaporator 2, completing the cycle.
[0073] Deep cold seawater (state point 15) is pumped to condenser 2 (state point 16) by a cold seawater pump. After exchanging heat with the working fluid in condenser 2 (state point 17), it enters condenser 1, exchanges heat with the working fluid in the first stage of the cycle, and is then discharged (state point 18).
[0074] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.
[0075] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.
[0076] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.
Claims
1. A combined ocean thermal energy conversion and geothermal energy driven cycle power generation system, characterized in that, The system includes a circulating power generation path and a heat source supply component; The circulating power generation path includes: an evaporator, a heat storage container, a generator, and an expander. The evaporator, the heat storage container, and the expander are connected in series. The evaporator is also connected to the heat source supply component. The heat storage container stores geothermal water. The evaporator is used to heat the initial liquid working fluid with warm seawater provided by the heat source supply component to obtain a gaseous working fluid. The heat storage container is used to heat the gaseous working fluid with the geothermal water to obtain a heated gaseous working fluid, wherein the temperature of the geothermal water is higher than the temperature of the gaseous working fluid. The expander is used to transfer the heated gaseous working fluid to the generator for power generation.
2. The circulating power generation system as described in claim 1, characterized in that, The circulating power generation path also includes: a condenser and a working fluid pump; The condenser is connected to the expander and the working fluid pump respectively, and the working fluid pump is also connected to the evaporator; The generator is used to transmit the gaseous working fluid after it has done work to the expander. The gaseous working fluid after it has done work is the gaseous working fluid obtained by the generator after it generates electricity using the heated gaseous working fluid. The expander is used to transfer the gaseous working fluid after work to the condenser; The condenser is used to condense the gaseous working fluid after work is done to obtain the initial liquid working fluid, and the initial liquid working fluid is transferred to the evaporator by the working fluid pump.
3. The circulating power generation system as described in claim 2, characterized in that, The system also includes a cold source supply component connected to the condenser; The condenser is used to condense the gaseous working fluid after it has done work using cold seawater supplied by the cold source supply component.
4. The circulating power generation system as described in claim 3, characterized in that, The circulating power generation path consists of at least two sets.
5. The circulating power generation system as described in claim 4, characterized in that, The evaporator of the previous set of circulating power generation paths is connected to the evaporator of the next set of circulating power generation paths through the warm seawater supply pipe in the heat source supply assembly. The evaporator of the previous set of circulating power generation paths is used to heat the initial liquid working fluid in the previous set of circulating power generation paths using the warm seawater, and then transmits it to the evaporator of the next set of circulating power generation paths through the warm seawater supply pipe. The evaporator in the next cycle power generation path is used to heat the initial liquid working fluid in the next cycle power generation path with warm seawater that has been heated by the initial liquid working fluid in the previous cycle power generation path.
6. The circulating power generation system as described in claim 5, characterized in that, The condenser in the previous set of circulating power generation paths is connected to the condenser in the next set of circulating power generation paths; The condenser in the previous set of circulating power generation paths is used to condense the gaseous working fluid after work is done in the previous set of circulating power generation paths using the cold seawater, and to transfer the condensed cold seawater to the condenser in the next set of circulating power generation paths. The condenser in the next set of circulating power generation paths is used to condense the gaseous working fluid that has done work in the next set of circulating power generation paths using the condensed cold seawater.
7. The circulating power generation system as described in claim 6, characterized in that, The cold source supply components include a cold seawater booster pump and a cold seawater supply pipeline; The cold seawater booster pump is connected to the cold seawater supply pipeline, and the condenser in the last set of circulating power generation paths is connected to the cold seawater supply pipeline. The cold seawater booster pump is also connected to the target ocean and the condenser in the first set of circulating power generation paths. The cold seawater booster pump is used to transfer cold seawater from the target ocean to the condenser in the first set of circulating power generation paths; The cold seawater booster pump is also used to receive cold seawater from the condenser in the last set of circulating power generation paths through the cold seawater supply pipeline, and to output the cold seawater from the condenser in the last set of circulating power generation paths to the target ocean.
8. The circulating power generation system as described in claim 5, characterized in that, The warm seawater supply pipe is a corrosion-resistant pipe and has a one-way connection structure.
9. The circulating power generation system as described in claim 4, characterized in that, The initial liquid working fluid is the same in each of the circulating power generation paths.
10. The circulating power generation system as described in claim 1, characterized in that, The evaporator is a shell-and-tube heat exchanger.