Organic working medium closed cycle power generation system for heat recovery of bathing wastewater

Abstract

The invention relates to the technical field of waste heat recovery, in particular to an organic working medium closed cycle power generation system for heat recovery of bathing wastewater. The invention provides an organic working medium closed cycle power generation system for heat recovery of bathing wastewater. The system comprises a filter, a working medium closed loop and a power generator, the working medium closed loop comprises a working medium pump, an evaporator, an expansion machine and a buried condenser, the working medium pump, the evaporator, the expansion machine and the buried condenser are sequentially communicated, and an initial working medium is stored in the evaporator; the filter is communicated with the bathing wastewater and connected with the evaporator, and the filter is used for pretreating the bathing wastewater to obtain pretreated water; the evaporator is used for heating the initial working medium based on the pretreated water to obtain a vaporized working medium; the expansion machine is used for receiving the steam working medium and driving the generator; the buried condenser is used for condensing the working steam working medium to obtain a liquid working medium; the working medium pump is used for returning the liquid working medium to the evaporator, and the utilization rate of low-temperature wastewater is increased.

Description

Technical Field

[0001] This application relates to the field of waste heat recovery technology, and in particular to an organic working fluid closed-loop power generation system for heat recovery from bathing wastewater. Background Technology

[0002] In the daily water usage of buildings, bathing activities generate a large amount of wastewater whose temperature is still within the usable range. This type of bathing wastewater is usually simply discharged directly into the drainage system, without effectively recovering the heat it carries. Traditional waste heat recovery technologies are mostly used in industrial settings, typically relying on high-temperature heat sources for energy conversion, which are unsuitable for the stable utilization of low-temperature heat sources like bathing wastewater with large flow fluctuations. Furthermore, existing low-temperature waste heat power generation systems are mostly built based on the organic Rankine cycle principle, resulting in large-scale devices that rely on cooling towers or external circulating cooling water for the condensation process. This makes the systems not only structurally complex but also difficult to deploy in small- to medium-scale scenarios such as residential bathing. Simultaneously, existing systems are prone to problems such as heat exchange structure blockage and decreased heat exchange efficiency when treating domestic wastewater containing impurities, further limiting the direct utilization of low-temperature wastewater and leading to low utilization rates. Therefore, improving the utilization rate of low-temperature wastewater has become an urgent technical problem to be solved. Summary of the Invention

[0003] This application provides an organic working fluid closed-loop power generation system for heat recovery from bathing wastewater, in order to improve the utilization rate of low-temperature wastewater.

[0004] To achieve the above objectives, this application provides an organic working fluid closed-loop power generation system for heat recovery from bathing wastewater, the system comprising a filter, a working fluid closed loop, and a generator; The working fluid closed loop includes a working fluid pump, an evaporator, an expander, and a buried condenser, which are connected in sequence. The evaporator stores the initial working fluid. The filter is connected to the bath wastewater and the evaporator. The filter is used to pre-treat the bath wastewater to obtain pre-treated water. The evaporator is used to heat the initial working fluid based on the pretreated water to obtain a vaporized working fluid; The expander is used to receive the vaporized chemical substance and drive the generator; The buried condenser is used to condense the vaporized working fluid after it has done work, to obtain a liquid working fluid; The working fluid pump is used to return the liquid working fluid to the evaporator.

[0005] In one embodiment, the filter includes a solid-liquid separation channel and a flow guiding channel; the solid-liquid separation channel is used to screen out impurities and output the pretreated water before the bath wastewater enters the evaporator; the flow guiding channel is used to introduce the pretreated water into the hot side of the evaporator and discharge it through the hot side outlet of the evaporator after heat exchange is completed.

[0006] In one embodiment, the evaporator is a liquid-filled structure and has a working fluid side inlet and a working fluid side outlet; the working fluid side inlet is connected to the outlet of the working fluid pump to receive the liquid working fluid, and the working fluid side outlet is connected to the inlet of the expander to output the vaporized working fluid.

[0007] In one embodiment, the evaporator includes a heat-side channel and a working fluid-side channel that are isolated from each other and transfer heat through a heat exchange wall; the inlet of the heat-side channel is connected to the outlet of the filter, and the outlet of the heat-side channel is connected to external drainage; the working fluid-side channel is used to guide the initial working fluid and the vaporized working fluid to flow within the working fluid closed loop.

[0008] In one embodiment, the expander and the generator are mechanically connected via a preset transmission component; the inlet of the expander is connected to the working fluid side outlet of the evaporator to receive the vaporized gas, and the outlet of the expander is connected to the inlet of the buried condenser to discharge the vaporized gas after work.

[0009] In one embodiment, the buried condenser is a tubular heat exchanger and is buried below the ground surface in a coiled manner; the buried condenser is in thermal contact with the surrounding soil, and when the vaporized gas after work is flowing along the internal channel, the vaporized gas after work is condensed into the liquid working fluid.

[0010] In one embodiment, the working fluid pump has an inlet and a outlet. The inlet is connected to the outlet of the buried condenser, and the outlet is connected to the working fluid side inlet of the evaporator via a return pipeline. The working fluid pump is used to pressurize the liquid working fluid and return it to the evaporator via the return pipeline.

[0011] In one embodiment, the initial working fluid is a low-boiling-point organic working fluid; the low-boiling-point organic working fluid is heated in the evaporator to become the vaporized working fluid, and after completing its work in the expander, it is condensed in the buried condenser to become the liquid working fluid, and then transported by the working fluid pump into the next cycle.

[0012] In one embodiment, the working fluid closed loop is provided with a steam supply channel and a liquid return channel; the steam supply channel is used to connect the working fluid side outlet of the evaporator to the inlet of the expander, and the liquid return channel is used to connect the outlet of the buried condenser to the suction port of the working fluid pump and the pressure outlet of the working fluid pump to the working fluid side inlet of the evaporator.

[0013] In one embodiment, the filter, the hot-side channel of the evaporator, and the external drainage constitute a heat source-side passage, which is independently set up with the working fluid closed loop; the heat source-side passage is used to exchange heat with the initial working fluid at the evaporator and to export the pretreated water from the system after the heat exchange is completed.

[0014] This application provides an organic working fluid closed-loop power generation system for heat recovery from bathing wastewater. The system includes a filter, a working fluid closed loop, and a generator. The working fluid closed loop includes a working fluid pump, an evaporator, an expander, and a buried condenser, which are connected in sequence. The evaporator stores the initial working fluid. The filter is connected to the bathing wastewater and the evaporator. The filter is used to pretreat the bathing wastewater to obtain pretreated water. The evaporator is used to heat the initial working fluid based on the pretreated water to obtain vaporized working fluid. The expander is used to receive the vaporized working fluid and drive the generator. The buried condenser is used to condense the vaporized working fluid after it has done work to obtain liquid working fluid. The working fluid pump is used to return the liquid working fluid to the evaporator. This application pre-treats bath wastewater through a filter, ensuring that the pre-treated water entering the evaporator can stably participate in heat exchange. The evaporator uses this pre-treated water to heat and vaporize the initial working fluid, effectively transferring the heat from the bath wastewater to the working fluid. The vaporized fluid enters the expander to perform work and drive the generator, realizing the conversion from thermal energy to mechanical energy. After performing work, the vaporized fluid is condensed into a liquid state by a buried condenser, restoring the circulating working fluid to a reheatable state. The working fluid pump returns the condensed liquid working fluid to the evaporator, allowing the working fluid to continuously circulate in a closed loop, thereby improving the utilization rate of low-temperature wastewater. Attached Figure Description

[0015] Figure 1 This is a structural block diagram of the first embodiment of the organic working fluid closed-loop power generation system for heat recovery from bathing wastewater according to this application; Figure 2 This is a structural block diagram of the working fluid closed-loop power generation system for heat recovery from bathing wastewater in the first embodiment of this application. Figure 3 This is a flowchart illustrating an embodiment of the organic working fluid closed-loop power generation system for heat recovery from bathing wastewater according to this application.

[0016] 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

[0017] 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.

[0018] It should be noted that during daily water use in buildings, bathing activities generate a large amount of wastewater whose temperature is still within the usable range. This type of bathing wastewater is usually simply discharged directly into the drainage system, and the heat it carries is not effectively recovered. Traditional waste heat recovery technologies are mostly used in industrial settings, typically relying on high-temperature heat sources for energy conversion, which is unsuitable for the stable utilization of low-temperature heat sources like bathing wastewater with large flow fluctuations. Furthermore, existing low-temperature waste heat power generation systems are mostly built based on the organic Rankine cycle principle, resulting in large-scale devices that rely on cooling towers or external circulating cooling water for the condensation process. This makes the systems not only structurally complex but also difficult to deploy in small- to medium-scale scenarios such as residential bathing. Simultaneously, existing systems are prone to problems such as heat exchange structure blockage and decreased heat exchange efficiency when treating domestic wastewater containing impurities, further limiting the direct utilization of low-temperature wastewater and leading to low utilization rates. Therefore, improving the utilization rate of low-temperature wastewater has become an urgent technical problem to be solved.

[0019] The main solution of this application is to provide an organic working fluid closed-loop power generation system for heat recovery from bathing wastewater. This system includes a filter, a working fluid closed loop, and a generator. The working fluid closed loop includes a working fluid pump, an evaporator, an expander, and a buried condenser, which are connected sequentially. The evaporator stores the initial working fluid. The filter is connected to the bathing wastewater and to the evaporator. The filter is used to pre-treat the bathing wastewater to obtain pre-treated water. The evaporator is used to heat the initial working fluid based on the pre-treated water to obtain vaporized working fluid. The expander is used to receive the vaporized working fluid and drive the generator. The buried condenser is used to condense the vaporized working fluid after it has done work to obtain liquid working fluid. The working fluid pump is used to return the liquid working fluid to the evaporator.

[0020] This application pre-treats bath wastewater through a filter, ensuring that the pre-treated water entering the evaporator can stably participate in heat exchange. The evaporator uses this pre-treated water to heat and vaporize the initial working fluid, effectively transferring the heat from the bath wastewater to the working fluid. The vaporized fluid enters the expander to perform work and drive the generator, realizing the conversion from thermal energy to mechanical energy. After performing work, the vaporized fluid is condensed into a liquid state by a buried condenser, restoring the circulating working fluid to a reheatable state. The working fluid pump returns the condensed liquid working fluid to the evaporator, allowing the working fluid to continuously circulate in a closed loop, thereby improving the utilization rate of low-temperature wastewater.

[0021] Reference Figure 1 and Figure 2 , Figure 1 This is a structural block diagram of the first embodiment of the organic working fluid closed-loop power generation system for heat recovery from bathing wastewater according to this application; Figure 2This is a structural block diagram of the working fluid closed-loop power generation system in the first embodiment of the organic working fluid closed-loop power generation system for heat recovery from bathing wastewater in this application.

[0022] In this first embodiment, the system includes a filter 11, a working fluid closed loop 12, and a generator 13; The working fluid closed loop includes a working fluid pump 121, an evaporator 122, an expander 123, and a buried condenser 124. The working fluid pump 121, the evaporator 122, the expander 123, and the buried condenser 124 are connected in sequence. The evaporator 122 stores the initial working fluid. The filter 11 is connected to the bath wastewater and the evaporator 122. The filter 11 is used to pre-treat the bath wastewater to obtain pre-treated water. The evaporator 122 is used to heat the initial working fluid based on the pretreated water to obtain a vaporized working fluid; The expander 123 is used to receive the vaporized substance and drive the generator 13; The buried condenser 124 is used to condense the vaporized working fluid after it has done work, so as to obtain a liquid working fluid; The working fluid pump 121 is used to return the liquid working fluid to the evaporator 122.

[0023] It should be noted that the filter is a device installed on the heat source side (connected to the bathing wastewater) to remove impurities in the bathing wastewater that may affect subsequent heat exchange or clog the heat exchange surface. The working fluid closed loop is a closed cycle consisting of a working fluid pump, evaporator, expander, buried condenser, and interconnecting pipelines. The working fluid pump is a pump installed in the closed loop, used to pressurize the condensed liquid working fluid and deliver it to the evaporator. The evaporator is a section of the working fluid closed loop, used to allow the initial liquid working fluid to absorb heat from the pretreated water and undergo a phase change to gas (vaporization). The expander is a mechanical device located in the gas flow path of the working fluid closed loop, used to receive the vaporized fluid and make it do work (usually manifested as rotational output) to drive a generator. The buried condenser is a condensation heat exchange device buried below the surface or in thermal contact with the underground environment, used to condense the vaporized fluid after it has done work, restoring it to a liquid working fluid. The initial working fluid is the working medium existing in a liquid state within the evaporator. Vaporized working fluid refers to the working medium in an evaporator that transforms from an initial liquid working fluid into a gaseous state after absorbing heat. Liquid working fluid refers to the liquid working medium obtained by condensing the vaporized working fluid after it has performed work in a buried condenser.

[0024] Specifically, the bathing wastewater first enters a filter connected to the system. The filter removes solid particles and impurities that could cause blockages, and then introduces the treated water (i.e., pretreated water) into the hot side of the evaporator. The evaporator contains a pre-stored liquid working fluid. The pretreated water contacts the heat exchange surface of the working fluid on the hot side of the evaporator. The heat from the pretreated water is transferred to the initial working fluid through the heat exchange wall, causing the initial working fluid to absorb heat and undergo a phase change, forming a vaporized fluid which is then discharged from the working fluid side outlet of the evaporator to enter the subsequent work-producing stage. Simultaneously, the evaporator discharges the heat-exchanged wastewater from the hot side or guides it to an external discharge path.

[0025] Furthermore, the vaporized propellant from the evaporator enters the expander along the steam supply channel. The expander uses the energy of the vaporized propellant to do work and generate mechanical output, which drives the generator mechanically connected to it to generate electrical energy. After the expander has done work, the vaporized propellant is introduced into the buried condenser through the exhaust channel. Under the thermal contact with the underground environment, the buried condenser condenses the vaporized propellant into a liquid working fluid. The condensed liquid working fluid is introduced into the suction port of the working fluid pump through the condenser outlet. The working fluid pump pressurizes the liquid working fluid and sends it back to the working fluid side inlet of the evaporator through the return pipeline, so that the working fluid completes one cycle in the closed loop and is ready to be heated and vaporized in the next round.

[0026] The filter pre-treats the wastewater entering the evaporator and stabilizes the heat exchange conditions. The evaporator transfers the heat from the pre-treated water to the initial working fluid, causing it to vaporize, thus converting the wastewater's thermal energy into the working fluid's phase change energy. The expander receives this vaporized fluid and converts its energy into mechanical energy to drive a generator to output electrical energy. The buried condenser condenses the vaporized fluid after it has done work, restoring the working fluid to a reheatable liquid state. The working fluid pump returns the condensed liquid phase to the evaporator, forming a continuous closed-loop cycle. Thus, the system ensures heat exchange stability through pre-treatment, converts thermal energy into electrical energy through phase change and work, and maintains cycle continuity through condensation and return, thereby continuously absorbing and utilizing the low-temperature heat carried by the bathing wastewater in a closed loop.

[0027] This embodiment provides an organic working fluid closed-loop power generation system for heat recovery from bathing wastewater. The system includes a filter, a working fluid closed loop, and a generator. The working fluid closed loop includes a working fluid pump, an evaporator, an expander, and a buried condenser, which are connected in sequence. The evaporator stores the initial working fluid. The filter is connected to the bathing wastewater and the evaporator. The filter is used to pre-treat the bathing wastewater to obtain pre-treated water. The evaporator is used to heat the initial working fluid based on the pre-treated water to obtain vaporized working fluid. The expander is used to receive the vaporized working fluid and drive the generator. The buried condenser is used to condense the vaporized working fluid after it has done work to obtain liquid working fluid. The working fluid pump is used to return the liquid working fluid to the evaporator. In this embodiment, the bath wastewater is pretreated by a filter, ensuring that the pretreated water entering the evaporator can stably participate in heat exchange. The evaporator uses this pretreated water to heat and vaporize the initial working fluid, effectively transferring the heat from the bath wastewater to the working fluid. The vaporized fluid enters the expander to perform work and drive the generator, realizing the conversion from thermal energy to mechanical energy. After performing work, the vaporized fluid is condensed into a liquid state by a buried condenser, allowing the circulating working fluid to return to a reheatable state. The working fluid pump returns the condensed liquid working fluid to the evaporator, allowing the working fluid to continuously circulate in a closed loop, thereby improving the utilization rate of low-temperature wastewater.

[0028] Please see Figure 3 , Figure 3 This is a flowchart illustrating an embodiment of the closed-loop organic working fluid power generation system for heat recovery from bathing wastewater according to this application. Based on the first embodiment described above, in one embodiment, the filter includes a solid-liquid separation channel and a flow guiding channel; the solid-liquid separation channel is used to screen out impurities and output the pretreated water before the bathing wastewater enters the evaporator; the flow guiding channel is used to introduce the pretreated water into the hot side of the evaporator and discharge it through the hot side outlet of the evaporator after heat exchange is completed.

[0029] It should be noted that the solid-liquid separation channel is a structure or flow path inside the filter used to separate solid impurities in bath wastewater from the water, filtering impurities through physical barriers, sieving, etc. The flow guide channel is a flow path or structure used to directionally transport the pretreated water after solid-liquid separation, directing it along a predetermined path to the hot side of the evaporator and discharging it after heat exchange. The hot side of the evaporator is the part of the evaporator isolated from the working fluid side, used to carry the flow of pretreated water and transfer heat to the working fluid side.

[0030] Specifically, the bathing wastewater first flows into the solid-liquid separation channel inside the filter. This channel separates impurities such as hair, particulate matter, and suspended solids from the water through sieving and blocking, effectively distinguishing the water from the solid impurities. The water after solid-liquid separation flows out of the channel outlet, becoming pre-treated water that can be used for subsequent heat exchange; while the impurities that are trapped are blocked outside the channel and do not enter the subsequent heat exchange device. Through this solid-liquid separation process, the water in contact with the hot side of the subsequent evaporator remains relatively clean, preventing impurities from adhering to or depositing on the heat exchange interface.

[0031] Furthermore, the pretreated water output from the solid-liquid separation channel is introduced into the guide channel inside the filter. The guide channel directionally transports this water to the hot side of the evaporator, allowing it to flow along the hot side flow path and form a heat exchange interface with the working fluid side partition wall. As the pretreated water flows through the heat exchange area on the hot side, its heat is transferred to the working fluid side through the wall, thereby heating the initial working fluid in the evaporator. After heat exchange, the water continues along the guide path and is finally discharged to the outside of the system through the hot side outlet of the evaporator, ensuring the continuity of the entire hot side flow process.

[0032] By setting up a solid-liquid separation channel, impurities can be removed before the bath wastewater enters the evaporator, thus avoiding blockage, deposition, or heat exchange surface contamination caused by impurities entering the evaporator's hot side. By setting up a flow guiding channel, the pretreated water can be stably and continuously guided to the evaporator's hot side, allowing the wastewater to participate in heat exchange in a suitable flow pattern and be smoothly discharged after heat exchange. The combination of solid-liquid separation and flow guiding makes the pretreated water flow more smoothly on the hot side and the heat exchange conditions more stable, thereby ensuring that the evaporator can fully absorb the heat carried by the bath wastewater, making the heat from the wastewater more efficient and reliable in the entire system.

[0033] Based on the first embodiment described above, in one embodiment, the evaporator is a liquid-filled structure and has a working fluid side inlet and a working fluid side outlet; the working fluid side inlet is connected to the outlet of the working fluid pump to receive the liquid working fluid, and the working fluid side outlet is connected to the inlet of the expander to output the vaporized working fluid.

[0034] It should be noted that a liquid-filled structure refers to an evaporator where the working fluid side is primarily filled with liquid working fluid during operation. This allows the working fluid to absorb heat in the liquid phase and vaporize in a localized area during heating. The working fluid side inlet is the location or interface on the evaporator's working fluid side where the liquid working fluid, delivered by the working fluid pump, is received. The working fluid side outlet is the location or interface on the evaporator's working fluid side where the vaporized working fluid, after heating, is discharged.

[0035] Specifically, the liquid working fluid, condensed in the buried condenser and pressurized by the working fluid pump, is transported to the working fluid-side inlet of the evaporator via a loop. Because the evaporator employs a liquid-filled structure, the working fluid, upon entering the evaporator, forms a predominantly liquid state within the working fluid side, ensuring a continuous and uniform flow within the evaporator. The connection between the working fluid-side inlet and the working fluid pump outlet ensures that the liquid working fluid enters the evaporator under pressure, allowing this portion of the working fluid to directly participate in the heat exchange process within the evaporator.

[0036] Furthermore, when the liquid working fluid enters the liquid-filled evaporator, it is heated on the working fluid side by pretreated water from the hot side, causing the liquid working fluid to gradually absorb heat and undergo a phase change, forming vaporized working fluid. As heating continues, some of the working fluid transforms into a gaseous state within the evaporation space and moves towards the working fluid side outlet along the flow pattern inside the evaporator. When vaporization reaches a certain level, the vaporized working fluid is discharged from the working fluid side outlet and fed into the expander along a closed loop, enabling it to enter the next stage of the power-generating process.

[0037] Because the evaporator adopts a liquid-filled structure with a working fluid inlet and outlet, the liquid working fluid can be continuously kept in a liquid phase and stably heated within the evaporator, thus making the heat absorption process of the working fluid more complete and continuous. The connection between the working fluid inlet and the outlet of the working fluid pump ensures that the liquid working fluid is reliably delivered into the evaporator under pressure, while the connection between the working fluid outlet and the expander inlet ensures that the vaporized fluid can smoothly enter the work-generating stage. Through the combined effect of these structures, the process of the working fluid from liquid heat absorption to vaporization output is continuous and controllable, which is beneficial to improving the heat absorption capacity of the working fluid in the evaporation stage, thereby more effectively converting the heat of bath wastewater into vaporized fluid that can be used for work.

[0038] Based on the first embodiment described above, in one embodiment, the evaporator includes a heat-side channel and a working fluid-side channel that are isolated from each other and transfer heat through a heat exchange wall; the inlet of the heat-side channel is connected to the outlet of the filter, and the outlet of the heat-side channel is connected to external drainage; the working fluid-side channel is used to guide the initial working fluid and the vaporized working fluid to flow within the working fluid closed loop.

[0039] It should be noted that the hot-side channel is the internal flow channel structure of the evaporator used to carry the flow of pretreated water and transfer heat to the working fluid side channel. The working fluid side channel is the internal flow channel structure of the evaporator used to accommodate the flow of the initial working fluid and the vaporized fluid; it is connected to the working fluid closed loop but isolated from the hot-side channel. The heat exchange wall is the isolation wall set between the hot-side channel and the working fluid side channel to achieve heat transfer without mixing the two.

[0040] Specifically, the pretreated water output from the filter flows into the hot-side channel of the evaporator via a connection interface. The structure of this channel allows the pretreated water to flow along a predetermined path into the evaporator. During its flow through the hot-side channel, the pretreated water is separated from the working fluid side channel by a heat exchange wall, through which it transfers the heat it carries to the working fluid side. After completing the heat transfer, the pretreated water continues to move along the hot-side channel and finally enters the external drainage path through the outlet of the hot-side channel, ensuring a smooth and continuous hot-side fluid flow path.

[0041] Furthermore, the working fluid side channel of the evaporator is independently set up and connected to the closed loop. The initial liquid working fluid is pumped into the working fluid side channel, moves along a predetermined flow path inside the channel, and forms thermal contact with the heat exchange wall. As the pretreated water continues to transfer heat to the wall, the initial liquid working fluid gradually absorbs heat and transforms into a gaseous state, forming vaporized fluid. The working fluid side channel further guides the vaporized fluid towards the evaporator outlet, enabling it to smoothly enter the next stage of the closed loop, namely the work process of the expander.

[0042] By isolating the hot-side channel and the working-side channel within the evaporator and using heat exchange walls for heat transfer, the pretreated water can continuously heat the initial working fluid without contacting it. The inlet of the hot-side channel is connected to the filter outlet and discharged to the outside after heat exchange, ensuring stable and controllable flow of the pretreated water. The working-side channel guides the initial working fluid to absorb heat, vaporize, and output it to subsequent equipment, maintaining continuous flow of the working fluid in a closed loop. This structural arrangement allows for efficient and reliable transfer of heat from the bathing wastewater to the working fluid, facilitating the fluid's transition from liquid to gas. This provides a stable vaporized working fluid for subsequent processes, thereby improving the effective utilization of the heat energy from the bathing wastewater.

[0043] In one embodiment, the expander and the generator are mechanically connected via a preset transmission component; the inlet of the expander is connected to the working fluid side outlet of the evaporator to receive the vaporized gas, and the outlet of the expander is connected to the inlet of the buried condenser to discharge the vaporized gas after work.

[0044] It should be noted that the pre-set transmission component is a structural component used to establish a mechanical connection between the expander and the generator and to transmit power.

[0045] Specifically, the vaporized refrigerant output from the evaporator's working fluid side outlet is transported to the expander inlet via a closed-loop pipeline. Upon receiving the vaporized refrigerant, the expander utilizes the energy generated by its expansion to rotate or move its internal mechanical components, thereby generating mechanical power that can be output. Since the expander and generator are mechanically connected via a pre-set transmission component, the mechanical output generated by the expander is transmitted to the generator through this transmission component, enabling the generator to output electrical energy under the action of power input.

[0046] Furthermore, after the vaporized propellant completes its expansion and work within the expander, its energy decreases, and it is discharged from the expander outlet in gaseous form. The expander outlet is connected to the inlet of the buried condenser via a pipeline, allowing the vaporized propellant to smoothly enter the condensation stage after work. Upon entering the buried condenser, the vaporized propellant will be gradually cooled and condensed in subsequent stages, preparing for the next step of the closed-loop working fluid return process. The direct connection between the expander outlet and the buried condenser inlet ensures that the working fluid continuously flows into the condensation stage after work, maintaining continuous operation of the closed loop.

[0047] By mechanically connecting the expander and generator via a pre-designed transmission component, the expansion energy of the vaporized substance within the expander can be directly used to drive the generator, achieving a continuous conversion from thermal energy to mechanical energy and then to electrical energy. Furthermore, the expander inlet is connected to the evaporator's working fluid outlet, allowing the vaporized substance produced by the evaporator to enter the power generation stage without obstruction. The expander outlet is connected to the buried condenser inlet, ensuring that the vaporized substance, after power generation, can smoothly enter the condensation process. This synergistic effect of the above structures creates a continuous and stable energy conversion chain for the vaporized substance during evaporation, power generation, and condensation, which helps improve the integrity of the working fluid cycle and further enhances the effectiveness of heat utilization from bathing wastewater.

[0048] Based on the first embodiment described above, in one embodiment, the buried condenser is a tubular heat exchanger and is buried below the ground surface in a coiled manner; the buried condenser is in thermal contact with the surrounding soil, and when the vaporized gas after work is flowing along the internal channel, the vaporized gas after work is condensed into the liquid working fluid.

[0049] It should be noted that a tubular heat exchanger is a heat exchange structure consisting of pipes, used to allow the working fluid to flow inside the pipes and exchange heat with the external environment through the pipe walls. The vaporized working fluid after work is referred to as the working medium that remains in a gaseous state after performing work in the expander.

[0050] Specifically, the vaporized propellant from the expander outlet, after performing work, is guided along a closed loop to the inlet of the buried condenser and enters the flow channels inside the heat exchanger. Because the buried condenser uses a tubular structure, the vaporized propellant continuously along the coiled pipes inside the heat exchanger, maintaining long-path contact with the pipe walls during its flow. As the vaporized propellant moves within the pipes, its internal pressure and temperature decrease, providing suitable starting conditions for the subsequent condensation process.

[0051] Furthermore, because the buried condenser is arranged in a coiled manner and buried below the surface, its outer surface is in thermal contact with the surrounding soil. When the vaporized working fluid flows inside the pipe after performing work, its heat is transferred to the soil through the pipe wall. As heat is continuously carried away, the vaporized working fluid gradually cools and undergoes a phase change inside the pipe, changing from a gaseous state to a liquid state. The condensed liquid working fluid is discharged at the pipe outlet and transported to the working fluid pump through a closed loop to enter the next cycle.

[0052] By burying the tubular heat exchanger underground in a coiled manner, a stable thermal contact is established between the heat exchange pipes and the underground soil. This allows the vaporized medium to continuously transfer its heat to the soil as it flows along the internal channels, thus facilitating the smooth condensation of the vaporized medium after it has performed work. The coiled arrangement extends the heat exchange path of the working medium in the underground environment, making the condensation process more complete. The condensed working medium is output in a liquid state, providing a stable inlet condition for the working medium pump to return it to the evaporator. Therefore, the buried condenser structure ensures the continuity and reliability of the working medium's recovery from a vaporized state to a liquid state, enabling the complete operation of the closed-loop circulation of the working medium and ensuring that the system can continuously absorb and utilize the heat from the bathing wastewater.

[0053] Based on the first embodiment described above, in one embodiment, the working fluid pump is provided with an inlet and a outlet. The inlet is connected to the outlet of the buried condenser, and the outlet is connected to the working fluid side inlet of the evaporator through a return pipeline. The working fluid pump is used to pressurize the liquid working fluid and return it to the evaporator through the return pipeline.

[0054] After condensation in the buried condenser, the liquid working fluid flows from the condenser outlet along a closed loop and enters the suction port of the working fluid pump. The suction port serves as the inlet port for the working fluid pump, enabling it to receive the condensed working fluid stably. Because the liquid working fluid is at a low temperature and in a stable state at this stage, it is suitable for pressurization, thus preparing it for the next stage of the cycle in the evaporator.

[0055] After receiving the liquid working fluid, the working fluid pump pressurizes it and outputs it from the pressure outlet. The pressurized liquid working fluid is transported along the return pipeline to the working fluid side inlet of the evaporator, allowing the working fluid to re-enter the evaporation zone and begin the next round of heat absorption and vaporization. Guided by the return pipeline, a stable flow path is formed between the working fluid pump output and the evaporator inlet, ensuring that the liquid working fluid enters the evaporator in a continuous and controlled manner.

[0056] By installing a working fluid pump and connecting its inlet to the outlet of the buried condenser, the stable collection of the condensed liquid working fluid can be ensured. By connecting the pump's pressure outlet to the evaporator's working fluid inlet via a return pipeline, the liquid working fluid can enter the evaporator under pressure and re-participate in evaporation and heat exchange. This structural arrangement makes the flow of the working fluid in the closed loop more continuous and controllable, ensuring a smooth transition from condensation to evaporation, thus guaranteeing stable working fluid circulation and providing a continuous flow of working fluid for absorbing heat from bath wastewater. This allows the overall system to more fully utilize the heat from the low-temperature wastewater.

[0057] In one embodiment, the initial working fluid is a low-boiling-point organic working fluid; the low-boiling-point organic working fluid is heated in the evaporator to become the vaporized working fluid, and after completing its work in the expander, it is condensed in the buried condenser to become the liquid working fluid, and then transported by the working fluid pump into the next cycle.

[0058] Specifically, the initial working fluid is a low-boiling-point organic fluid, existing in liquid form within the evaporator. Through the heat exchange process in the evaporator, this low-boiling-point organic fluid absorbs heat from the pretreated water, raising its temperature to a range where a phase change can occur, and gradually transitions from a liquid to a gaseous state within the evaporator. As heating continues, some of the liquid working fluid completely transforms into vaporized fluid and flows along the working fluid side outlet of the evaporator to the next stage of the closed loop.

[0059] Furthermore, the vaporized refrigerant output from the evaporator enters the expander, where it releases its energy and performs work through expansion. After performing work, the vaporized refrigerant exits the expander and enters the buried condenser, where it gradually loses heat during heat exchange with the underground soil, transforming from a gaseous state back into a liquid working fluid. The condensed liquid working fluid is then introduced through the condenser outlet into the suction inlet of the working fluid pump, where it is pressurized and delivered to the working fluid side inlet of the evaporator, entering the next cycle.

[0060] Because the initial working fluid is a low-boiling-point organic working fluid, it can be vaporized in the evaporator with the help of the low-temperature heat of the pretreated water, thus meeting the needs of subsequent expansion and work. After releasing energy in the expander, the vaporized working fluid is condensed into a liquid state by the buried condenser, so that it can be transported back to the evaporator in a stable state by the working fluid pump. Through this closed-loop cycle of vaporization, work, condensation and return, the working fluid can continuously participate in energy conversion and operate stably under low temperature difference conditions. As a result, the low-temperature heat carried by the bathing wastewater can be effectively absorbed and utilized in the cycle, realizing the continuous conversion and recovery of low-temperature wastewater heat energy.

[0061] In one embodiment, the working fluid closed loop is provided with a steam supply channel and a liquid return channel; the steam supply channel is used to connect the working fluid side outlet of the evaporator to the inlet of the expander, and the liquid return channel is used to connect the outlet of the buried condenser to the suction port of the working fluid pump and the pressure outlet of the working fluid pump to the working fluid side inlet of the evaporator.

[0062] Specifically, the vaporized medium, after undergoing heat absorption and phase change inside the evaporator, is discharged from the working medium side outlet of the evaporator and directly transported to the inlet of the expander via the steam supply channel in the working medium closed loop. The steam supply channel, serving as the flow path for the vaporized medium, allows it to enter the expander without any intermediate processing, ensuring its energy state is readily available for work. The connectivity of this channel ensures continuous and smooth transfer of the vaporized medium between the evaporator and the expander. After being used by the expander, the vaporized medium condenses in the buried condenser and, as a liquid working medium, is introduced from the condenser outlet into the return liquid channel, from which it is transported to the suction inlet of the working medium pump. The working medium pump pressurizes the suction liquid working medium and, through another section of the return liquid channel, transports the pressurized working medium from the pump's pressure outlet to the working medium side inlet of the evaporator. In this way, the condensed liquid working medium can smoothly return to the evaporator within the closed loop, completing the process preparation from condensation to reheating.

[0063] By separately setting up steam supply and liquid return channels in the closed-loop working fluid system, the flow paths of the vaporized and liquid working fluids are clearly separated. This ensures that the vaporized fluid can directly enter the expander from the evaporator to perform work, while the condensed liquid working fluid can be smoothly returned to the evaporator after being pressurized by the working fluid pump. The steam supply channel ensures that the energy of the vaporized fluid can be used to drive the expander in a timely manner, while the liquid return channel ensures that the liquid working fluid is effectively transported after condensation and restored to the heatable cycle starting point. This structure maintains the continuity and stability of the closed-loop system across the four stages of "vaporization—work—condensation—return," thereby improving the integrity and operating efficiency of the working fluid cycle and providing a reliable guarantee for the continuous utilization of heat from low-temperature wastewater in the system.

[0064] In one embodiment, the filter, the hot-side channel of the evaporator, and the external drainage constitute a heat source-side passage, which is independently set up with the working fluid closed loop; the heat source-side passage is used to exchange heat with the initial working fluid at the evaporator and to export the pretreated water from the system after the heat exchange is completed.

[0065] Specifically, the bathing wastewater first enters the filter, where impurities are removed to generate pretreated water. This pretreated water then enters the hot-side channel of the evaporator along the heat source side passage, flowing forward along a predetermined path within the hot-side channel. The hot-side channel and the working fluid side channel are isolated by a heat exchange wall. As the pretreated water flows through the hot side, the heat it carries is gradually transferred from the hot-side channel to the working fluid side, thus heating the initial working fluid within the evaporator.

[0066] Furthermore, after exchanging heat with the initial working fluid in the evaporator, the pretreated water continues to flow towards the outlet along the hot-side passage and is discharged from the system through an external drainage path. Throughout the process, the heat source-side passage remains independent of the working fluid closed loop, preventing fluid mixing and ensuring that the pretreated water only participates in heat exchange as a heat carrier, without participating in the working fluid circulation. This three-stage process of inlet, heat exchange, and discharge ensures that the pretreated water is directly discharged from the system after fulfilling its heat source supply function on the hot side of the evaporator.

[0067] By constructing an independently configured heat source-side passage consisting of a filter, an evaporator hot-side channel, and external drainage, the bath wastewater is pretreated before entering the evaporator and undergoes stable heat exchange with the initial working fluid at the evaporator, while avoiding mixing with the working fluid in a closed loop. After heat exchange, the pretreated water is directly discharged from the heat source-side passage, ensuring that this passage always maintains a unidirectional flow state, which is conducive to maintaining stable heat input conditions. Therefore, the system structurally ensures the functional independence of the heat source water path and the working fluid loop, making the utilization of bath wastewater as a heat source more reliable and controllable. This improves the working fluid's ability to absorb heat from low-temperature wastewater during the evaporation stage, further enhancing the effective utilization rate of heat from the bath wastewater.

[0068] This embodiment provides an organic working fluid closed-loop power generation system for heat recovery from bathing wastewater. The system includes a filter, a working fluid closed loop, and a generator. The working fluid closed loop includes a working fluid pump, an evaporator, an expander, and a buried condenser, which are connected in sequence. The evaporator stores the initial working fluid. The filter is connected to the bathing wastewater and the evaporator. The filter is used to pre-treat the bathing wastewater to obtain pre-treated water. The evaporator is used to heat the initial working fluid based on the pre-treated water to obtain vaporized working fluid. The expander is used to receive the vaporized working fluid and drive the generator. The buried condenser is used to condense the vaporized working fluid after it has done work to obtain liquid working fluid. The working fluid pump is used to return the liquid working fluid to the evaporator. In this embodiment, the bath wastewater is pretreated by a filter, ensuring that the pretreated water entering the evaporator can stably participate in heat exchange. The evaporator uses this pretreated water to heat and vaporize the initial working fluid, effectively transferring the heat from the bath wastewater to the working fluid. The vaporized fluid enters the expander to perform work and drive the generator, realizing the conversion from thermal energy to mechanical energy. After performing work, the vaporized fluid is condensed into a liquid state by a buried condenser, allowing the circulating working fluid to return to a reheatable state. The working fluid pump returns the condensed liquid working fluid to the evaporator, allowing the working fluid to continuously circulate in a closed loop, thereby improving the utilization rate of low-temperature wastewater.

[0069] For example, please refer to Figure 3 .like Figure 3 As shown, bath wastewater enters the evaporator after being filtered through a filter, where its heat is transferred to the working fluid. The outlet of the evaporator is connected to the inlet of the turbine expander. In the turbine, the working fluid converts its internal energy into mechanical energy, which is then transferred to the generator, ultimately converting into electrical energy. The hot water outlet of the evaporator discharges the cooled wastewater through a pipeline. The turbine outlet is connected to the inlet of the condenser to cool the working fluid to a liquid state. The condenser outlet is connected to the inlet of the working fluid pump, which pressurizes the liquid working fluid to the corresponding saturated vapor pressure. The working fluid outlet of the pump is connected to the working fluid inlet of the evaporator, forming a working fluid circulation loop.

[0070] Bath wastewater (state point 1) is filtered and then enters the evaporator (state point 2), where it exchanges heat with the liquid working fluid (state point 6). The heat-exchanged bath wastewater (state point 7) is discharged through pipeline. The working fluid, heated to a gaseous state (state point 3), enters the expander, where its internal energy is converted into mechanical energy. The generator connected to the expander then converts the mechanical energy into electrical energy. The exhaust steam from the expander outlet enters the condenser (state point 4), condenses into a liquid, and is pressurized by the working fluid pump (state point 5). It then enters the evaporator (state point 6), completing the working fluid cycle.

[0071] 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.

[0072] 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.

[0073] 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 closed-loop organic working fluid power generation system for heat recovery from bathing wastewater, characterized in that, The system includes a filter, a closed-loop working fluid circuit, and a generator; The working fluid closed loop includes a working fluid pump, an evaporator, an expander, and a buried condenser, which are connected in sequence. The evaporator stores the initial working fluid. The filter is connected to the bath wastewater and the evaporator. The filter is used to pre-treat the bath wastewater to obtain pre-treated water. The evaporator is used to heat the initial working fluid based on the pretreated water to obtain a vaporized working fluid; The expander is used to receive the vaporized chemical substance and drive the generator; The buried condenser is used to condense the vaporized working fluid after it has done work, to obtain a liquid working fluid; The working fluid pump is used to return the liquid working fluid to the evaporator.

2. The system as described in claim 1, characterized in that, The filter includes a solid-liquid separation channel and a flow guiding channel; the solid-liquid separation channel is used to screen out impurities and output the pretreated water before the bath wastewater enters the evaporator; the flow guiding channel is used to introduce the pretreated water into the hot side of the evaporator and discharge it through the hot side outlet of the evaporator after heat exchange is completed.

3. The system as described in claim 1, characterized in that, The evaporator is a liquid-filled structure and has a working fluid side inlet and a working fluid side outlet; the working fluid side inlet is connected to the outlet of the working fluid pump to receive the liquid working fluid, and the working fluid side outlet is connected to the inlet of the expander to output the vaporized working fluid.

4. The system as described in claim 3, characterized in that, The evaporator includes a heat-side channel and a working fluid-side channel that are isolated from each other and transfer heat through a heat exchange wall; the inlet of the heat-side channel is connected to the outlet of the filter, and the outlet of the heat-side channel is connected to external drainage; the working fluid-side channel is used to guide the initial working fluid and the vaporized working fluid to flow in the working fluid closed loop.

5. The system as described in claim 4, characterized in that, The expander and the generator are mechanically connected via a preset transmission component; the inlet of the expander is connected to the working fluid side outlet of the evaporator to receive the vaporized gas, and the outlet of the expander is connected to the inlet of the buried condenser to discharge the vaporized gas after work.

6. The system as described in claim 1, characterized in that, The buried condenser is a tubular heat exchanger and is buried below the ground surface in a coiled manner; the buried condenser is in thermal contact with the surrounding soil, and when the vaporized gas after work is flowing along the internal channel, the vaporized gas after work is condensed into the liquid working fluid.

7. The system as described in claim 5, characterized in that, The working fluid pump is provided with an inlet and a outlet. The inlet is connected to the outlet of the buried condenser, and the outlet is connected to the working fluid side inlet of the evaporator through a return pipeline. The working fluid pump is used to pressurize the liquid working fluid and return it to the evaporator through the return pipeline.

8. The system as described in claim 1, characterized in that, The initial working fluid is a low-boiling-point organic working fluid; the low-boiling-point organic working fluid is heated in the evaporator to become the vaporized working fluid, and after completing its work in the expander, it is condensed in the buried condenser to become the liquid working fluid, and then transported by the working fluid pump into the next cycle.

9. The system as described in claim 7, characterized in that, The working fluid closed loop is provided with a steam supply channel and a liquid return channel; the steam supply channel is used to connect the working fluid side outlet of the evaporator to the inlet of the expander, and the liquid return channel is used to connect the outlet of the buried condenser to the suction port of the working fluid pump and the pressure outlet of the working fluid pump to the working fluid side inlet of the evaporator.

10. The system according to any one of claims 1-9, characterized in that, The filter, the hot-side channel of the evaporator, and the external drainage form a heat source side passage. The heat source side passage and the working fluid closed loop are set independently of each other. The heat source side passage is used to exchange heat with the initial working fluid at the evaporator and to export the pretreated water from the system after the heat exchange is completed.

Images