A work-generating system and method capable of utilizing a low-temperature heat source

Abstract

The present invention discloses a working system and method that can utilize a low-temperature heat source. The working system that can utilize a low-temperature heat source includes a working medium circulation working system, and the working medium circulation working system includes a pressure generator, a working device and an evaporator. The pressure generator, the working device and the evaporator are connected end to end in sequence to allow the working medium to circulate; the evaporator obtains steam working medium and liquid working medium below room temperature in the process of vaporizing the working working medium, and the liquid working medium below room temperature absorbs heat from a low-temperature heat source before or after returning to the pressure generator, and the steam working medium returns to the pressure generator to heat the liquid working medium and increase the steam pressure in the pressure generator to drive the liquid working medium to do work in the working device. The working system that can utilize a low-temperature heat source can utilize the low-temperature heat source in the environment, reduce energy consumption and save energy.

Description

Technical Field

[0001] The present invention relates to the technical field of cyclic work or power generation, and in particular to a work system and method that can utilize a low-temperature heat source. Background Art

[0002] So far, most devices that produce work or generate electricity use the expansion of high-temperature and high-pressure gas to achieve work or power generation. There are two ways to form high-temperature and high-pressure gas: one is to directly form high-temperature and high-pressure gas through fuel combustion; the other is to heat liquid working fluids, such as water, through fuel combustion to evaporate the liquid working fluid to form high-temperature and high-pressure gas, such as internal combustion engines, gas turbines, steam engines, etc.

[0003] The method of directly obtaining high-temperature and high-pressure gas through fuel combustion has high requirements on the temperature and pressure of the gas. When the gas temperature and pressure drop to a certain value, the gas is no longer suitable for doing work and can only be discharged as exhaust gas, so the thermal efficiency is relatively low.

[0004] The liquid working fluid is heated by heating to evaporate into high-temperature and high-pressure gas. The gas working fluid does work. After the gas working fluid does work, the temperature and pressure drop to a very low level, making it difficult to directly recycle and reuse. The gas working fluid can only be liquefied into liquid working fluid, and then heated into high-temperature and high-pressure gas before doing work. This process discharges a large amount of low-temperature heat energy into the environment, and the latent heat of vaporization of the working fluid is much higher than the specific heat capacity, so the thermal efficiency is relatively low.

[0005] In addition, most of the current refrigeration systems use compressors to compress the vapor of the refrigerant, causing the vapor pressure in the evaporator to decrease, prompting the refrigerant to evaporate to achieve the purpose of cooling. The high-temperature and high-pressure steam generated by the compressor passes through the condenser and dissipates heat to the surrounding environment through the condensing medium. In this process, not only a large amount of low-temperature heat energy is lost, but also a large amount of cooling water is lost.

[0006] In summary, existing working devices and power generation devices waste a large amount of low-temperature thermal energy on the one hand, and on the other hand, fail to utilize a large amount of existing low-temperature heat sources or waste heat. Summary of the invention

[0007] The object of the present invention is to provide a work system and method that can utilize a low-temperature heat source, so as to solve the problems of waste of existing low-temperature thermal energy and inability to utilize low-temperature heat sources.

[0008] To achieve the above-mentioned purpose, the technical solution of the present invention is to provide a working system that can utilize a low-temperature heat source, wherein the working system that can utilize a low-temperature heat source includes a working fluid circulation working system, wherein the working fluid circulation working system includes a pressure generator, a working device and an evaporator, wherein the pressure generator, the working device and the evaporator are connected end to end in sequence for the circulation of the working fluid; the evaporator obtains steam working fluid and liquid working fluid below room temperature in the process of vaporizing the working working fluid, and the liquid working fluid below room temperature absorbs heat from the low-temperature heat source before or after returning to the pressure generator, and the steam working fluid returns to the pressure generator to heat the liquid working fluid and increase the steam pressure in the pressure generator to drive the liquid working fluid to do work in the working device.

[0009] Preferably, the working medium cycle work system further comprises a steam compression device, which is connected in series between the evaporator and the pressure generator, and compresses the steam working medium generated by the evaporator to reduce the pressure of the steam in the evaporator, and pressurizes the compressed steam working medium to the pressure generator;

[0010] Alternatively, the working fluid circulation working system also includes a steam processing device, and a steam absorbing working fluid is provided in the evaporator, and the steam absorbing working fluid absorbs the steam of the working working fluid to reduce the pressure of the steam in the evaporator, and the absorbed working working fluid is transported to the steam processing device together with the steam absorbing working fluid to separate the working working fluid from the steam absorbing working fluid, and the working working fluid is returned to the pressure generator in the form of liquid or steam.

[0011] Preferably, the work system that can utilize a low-temperature heat source includes n stages of the working medium circulation work system connected step by step, and the evaporator of the previous stage and the steam compression device of the next stage are arranged in a heat exchange manner, wherein n is a positive integer greater than or equal to 2.

[0012] Preferably, the working system that can utilize a low-temperature heat source further comprises a steam working system, the steam working system comprises a steam working system pressure generator, a steam working system working device and a steam working system working fluid pump, and the steam working system pressure generator, the steam working system working device and the steam working system working fluid pump are connected end to end in sequence;

[0013] Furthermore, the pressure generator of the steam working system is arranged in a heat exchange manner with the steam compression device of the working medium cycle working system, and the working device of the steam working system is arranged in a heat exchange manner with the evaporator of the working medium cycle working system;

[0014] Alternatively, the working device of the steam working system and the pressure generator of the working medium cycle working system are arranged in a heat exchange manner.

[0015] Preferably, a steam power system comprises a steam power system pressure generator and a steam power system power device, wherein the steam power system pressure generator, the steam power system power device, the pressure generator, the power device and the evaporator are connected end to end in sequence, so that the working fluid circulates in the steam power system pressure generator, the steam power system power device, the pressure generator, the power device and the evaporator in sequence, and the working fluid outlet of the pressure generator is connected to the working fluid inlet of the steam power system pressure generator, and the working fluid outlet of the evaporator is connected to the working fluid inlet of the pressure generator.

[0016] Preferably, the working system that can utilize a low-temperature heat source includes a plurality of the pressure generators and a plurality of working devices arranged in parallel, the plurality of pressure generators cyclically receive the liquid working medium and the steam working medium output by the evaporator in sequence, and the plurality of working devices are arranged in parallel and perform work in this cycle.

[0017] Preferably, a heating source is provided in the pressure generator. When the pressure generator receives the liquid working medium at a temperature below room temperature, the liquid working medium first absorbs heat from the low-temperature heat source and is then heated by the heating source to increase the steam pressure in the pressure generator.

[0018] Preferably, the working fluid includes a first working fluid and a second working fluid, and the first working fluid can be mixed with the second working fluid, or dissolved in the second working fluid; in the evaporator, the working fluid vapor is absorbed by the steam absorbing fluid, thereby reducing the vapor pressure of the working fluid in the evaporator, and the absorbed working fluid vapor is transported to the steam processing device together with the steam absorbing fluid, so that the steam is separated from the steam absorbing fluid and returned to the pressure generator in the form of liquid or steam.

[0019] Among them, the working fluid circulation working system also includes a first heat exchanger and / or a second heat exchanger, the working fluid inlet of the first heat exchanger is connected to the working fluid outlet of the pressure generator, the working fluid outlet of the first heat exchanger is connected to the working fluid inlet of the working device, and the first heat exchanger is used to reduce the temperature of the working fluid entering the working device; the working fluid inlet of the second heat exchanger is connected to the working fluid outlet of the working device, the working fluid outlet of the second heat exchanger is connected to the working fluid inlet of the evaporator, and the second heat exchanger is used to increase the temperature of the working fluid entering the evaporator.

[0020] Preferably, the working system that can utilize a low-temperature heat source further comprises an energy storage device, wherein the energy storage device is connected to an energy output end of the working device and is used to store energy output by the working device.

[0021] The present invention also provides a method for performing work using a low-temperature heat source. The method is based on the work-performing system provided by the present invention, and the method comprises the following steps:

[0022] Step S1, heating the liquid working medium in the pressure generator to vaporize it and increase the pressure of the steam in the pressure generator to pressurize the liquid working medium to the working device;

[0023] Step S2, the liquid working medium is pressed to the evaporator after completing work in the working device;

[0024] Step S3, the liquid working medium is vaporized in the evaporator to obtain steam working medium, and at the same time, the steam working medium is absorbed by the steam absorption working medium in the evaporator and discharged from the evaporator;

[0025] Step S4, separating the steam working medium from the steam absorption working medium, and returning the separated steam working medium to the pressure generator, while returning the steam absorption working medium to the evaporator.

[0026] The present invention has the following advantages:

[0027] The working system that can utilize a low-temperature heat source provided by the present invention can generate a low-temperature liquid working medium and a steam working medium below room temperature when the working medium evaporates in the evaporator. The low-temperature liquid working medium absorbs heat from the low-temperature heat source in the pressure generator or before entering the pressure generator, so that its temperature reaches the temperature of the low-temperature heat source, and then is heated by the heating source to further increase the temperature of the working medium and vaporize it. Since the liquid working medium absorbs the heat from the low-temperature heat source, the energy consumption can be reduced during vaporization, and in the pressure generator, the low-temperature liquid working medium can be heated or vaporized by the heat in the high-temperature steam working medium output by the evaporator, thereby recycling the heat discharged by the evaporator. Therefore, the working system not only utilizes low-temperature heat sources in environments such as air, rivers, lakes, and seas, expanding the source range of energy, but also recycles the heat in the steam working medium generated by the evaporator, saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the connection relationship of a working medium circulation working system in a working system that can utilize a low-temperature heat source provided in Example 1 of the present invention;

[0029] Figure 2 A schematic diagram of the connection relationship of a working medium circulation working system in a working system that can utilize a low-temperature heat source provided in a preferred embodiment of embodiment 1 of the present invention;

[0030] Figure 3 A schematic diagram of the connection relationship of a working medium circulation working system in a working system that can utilize a low-temperature heat source provided in Example 2 of the present invention;

[0031] Figure 4 A schematic diagram of the connection relationship of a working medium circulation working system in a working system that can utilize a low-temperature heat source provided in Example 3 of the present invention;

[0032] Figure 5 A schematic diagram of the connection relationship between two working fluid circulation systems in a work system that can utilize a low-temperature heat source provided in Example 4 of the present invention;

[0033] Figure 6 A schematic diagram of the connection relationship between the working fluid system and the steam working device in the working system that can utilize a low-temperature heat source provided in Example 5 of the present invention;

[0034] Figure 7 A schematic diagram of the connection relationship between the working fluid system and the steam working device in the working system that can utilize a low-temperature heat source provided in Example 6 of the present invention;

[0035] Figure 8 A schematic diagram of the connection relationship between the working fluid system and the steam working device in the working system that can utilize a low-temperature heat source provided in Example 7 of the present invention;

[0036] Fig. 9 A schematic diagram of the connection relationship between the working fluid system and the refrigeration system in the work system that can utilize a low-temperature heat source provided in Example 8 of the present invention;

[0037] Fig.10 A flow chart of a method for performing work using a low-temperature heat source provided in Example 9 of the present invention.

[0038] In the above figures, the solid line represents the flow of liquid working medium, the dotted line represents the flow of steam working medium, and the dot-dash line represents heat exchange. DETAILED DESCRIPTION

[0039] The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0040] Example 1

[0041] like Figure 1As shown, the working system that can utilize the low-temperature heat source provided in Example 1 includes a working fluid circulation working system 1, and the working fluid circulation working system 1 includes a pressure generator 11, a working device 12 and an evaporator 13. The pressure generator 11, the working device 12 and the evaporator 13 are connected end to end in sequence through pipelines, that is, the working fluid outlet of the pressure generator 11 and the working fluid inlet of the working device 12 are connected through pipelines, the working fluid outlet of the working device 12 and the working fluid inlet of the evaporator 13 are connected through pipelines, and the working fluid outlet of the evaporator 13 and the input port of the pressure generator 11 are connected through pipelines. The working fluid circulates among the pressure generator 11, the working device 12 and the evaporator 13 through the pipeline, and the pressure difference of the working fluid between the pressure generator 11 and the evaporator 13 provides the working device 12 with power for working.

[0042] It should be pointed out that the working fluid inlet of the pressure generator 11 includes a liquid working fluid inlet and a steam working fluid inlet, and the working fluid outlet of the evaporator 13 includes a liquid working fluid outlet and a steam working fluid outlet. It is not difficult to understand that the liquid working fluid outlet of the evaporator 13 is correspondingly connected to the liquid working fluid inlet of the pressure generator 11, and the steam working fluid outlet of the evaporator 13 is correspondingly connected to the steam working fluid inlet of the pressure generator 11. For the convenience of description, in most cases below, the liquid working fluid inlet and the steam working fluid inlet of the pressure generator 11 are collectively referred to as the working fluid inlet of the pressure generator 11, and the liquid working fluid outlet and the steam working fluid outlet of the evaporator 13 are collectively referred to as the working fluid outlet of the evaporator 13. Only when the liquid working fluid and the steam working fluid are particularly emphasized, the steam working fluid inlet, the steam working fluid outlet, the liquid working fluid inlet or the liquid working fluid outlet are specifically used.

[0043] A relatively high steam pressure needs to be generated in the pressure generator 11 to pressurize the working fluid into the working device 12 to do work, and then be pressed into the evaporator 13. However, when the temperature of the working fluid is too high, it will have an adverse effect on the life of the working device 12. Therefore, it is necessary to reduce the temperature of the working fluid entering the working device 12. In other words, the working fluid in the pressure generator 11 needs to absorb heat to increase the working fluid temperature and steam pressure, and also needs to release heat to reduce the temperature entering the working device 12. It can be simply considered that the pressure generator 11 is divided into three sections. The front section and the middle section need to absorb heat to increase the steam pressure, that is, increase the pressure difference between the pressure generator 11 and the evaporator 13, thereby improving the efficiency of work; the rear section needs to release heat to reduce the adverse effects of the working fluid on the working device 12.

[0044] The evaporator 13 is used to vaporize the working medium. When the working medium is vaporized in the evaporator 13, a large amount of heat needs to be absorbed, resulting in the temperature of the unvaporized liquid medium being reduced to below room temperature. The low-temperature liquid medium can absorb heat from a low-temperature heat source, which includes but is not limited to air, rivers, lakes, and seas.

[0045] In this embodiment, the evaporator 13 may be a refrigeration evaporator, and an expansion device is provided at the working medium inlet of the refrigeration evaporator, that is, the working medium outlet of the working device 12 is connected to the working medium inlet of the expansion device through a conduit, and the working medium outlet of the expansion device is connected to the working medium inlet of the evaporator 13 through a conduit. The expansion device can expand the working medium, thereby facilitating the evaporator 13 to evaporate and vaporize the working medium.

[0046] In this embodiment, a heat exchanger (not shown) is provided in the pressure generator 11. When the working fluid in the pressure generator 11 is lower than the room temperature, the working fluid absorbs heat from the low-temperature heat source through the heat exchanger and raises the temperature of the working fluid to the room temperature.

[0047] In addition, even if the low-temperature liquid working fluid absorbs the heat of the low-temperature heat source, this heat is not enough to make the working fluid work on the working device. Therefore, in this embodiment, a heating source (not shown in the figure) can also be provided in the pressure generator 11. The heating source serves as a higher temperature heat source to increase the temperature of the working fluid and evaporate the working fluid. When the working device 12 needs to output a larger power, the heating source can increase the pressure of the steam working fluid and increase the pressure difference between the pressure generator 11 and the evaporator 13, so that the working device 12 provides a larger output power.

[0048] In addition, the heating source can also be arranged outside the pressure generator 11 to heat the working medium outside the pressure generator 11; or, the heating source can be used to heat the heat-conducting medium, and then the heat-conducting medium can heat the working medium.

[0049] It should be noted that the working fluid circulation system provided in this embodiment may be provided with only one of the heat exchanger and the heating source, or may be provided with both the heat exchanger and the heating source.

[0050] As a preferred embodiment of this embodiment, Figure 2 As shown, the working medium cycle working system also includes a steam compression device 14, which is connected in series between the evaporator 13 and the pressure generator 11, that is, the working medium inlet of the steam compression device 14 is connected to the working medium outlet of the evaporator 13 through a pipeline, and the working medium outlet of the steam compression device 14 is connected to the inlet of the pressure generator 11 through a pipeline. The steam compression device 14 can compress the steam working medium generated by the evaporator 13. On the one hand, it reduces the pressure of the steam in the evaporator 13, so that the pressure in the evaporator 13 is maintained within a lower range, thereby increasing the pressure difference between the pressure generator 11 and the evaporator 13, and then improving the working efficiency of the working device; on the other hand, it obtains high-temperature and high-pressure steam working medium, and compresses the high-temperature and high-pressure steam working medium into the pressure generator 11 to circulate its heat, thereby reducing the waste of heat energy.

[0051] In this embodiment, the evaporator 13 is a flash tank evaporator. The steam working medium generated by the flash tank evaporator is compressed by the steam compression device 14 and then sent to the pressure generator 11. The low-temperature liquid working medium generated by the flash tank evaporator can be returned to the pressure generator 11 through a working medium pump (not shown in the figure). Before entering the pressure generator 11, the low-temperature liquid working medium can first absorb the heat in the environment to make it substantially the same as the ambient temperature, and then enter the pressure generator 11 to heat up and vaporize. Since the low-temperature liquid working medium has absorbed the heat in the environment, the energy required for vaporization of the liquid working medium can be reduced.

[0052] It is not difficult to understand that the steam compression device 14 increases the steam pressure in the pressure generator 11 while reducing the steam pressure in the evaporator 13, which is beneficial to improving the efficiency of the working device. In this embodiment, the steam compression device 14 adopts but is not limited to mechanical compression (such as a compressor) and a steam jet compression device.

[0053] In addition, the low-temperature liquid working medium generated in the flash tank evaporator 13 can also be pressure-sent to the pressure generator 11 through the pressure difference between the pressure generator 11 and the evaporator 13, that is, the steam working medium in the pressure generator 11 is extracted by the compressor, so that the pressure in the pressure generator 11 is less than the pressure in the evaporator 13, and the liquid working medium is pressure-sent from the evaporator 13 to the pressure generator 11 by the pressure difference. The low-temperature liquid working medium first absorbs heat from the low-temperature heat source in the environment through the heat exchanger in the pressure generator 13, and is heated by a higher heat source after the temperature of the liquid working medium is substantially the same as the ambient temperature.

[0054] In order to promote the evaporation of the liquid working medium in the evaporator 13, in addition to using compression to discharge the steam working medium, an absorption method can also be used. For example, by utilizing the characteristic of absorbing water vapor of the lithium bromide concentrated solution, the lithium bromide concentrated solution absorbs water vapor, reduces the pressure of water vapor in the evaporator 13, and promotes the evaporation of the liquid working medium in the evaporator. The lithium bromide dilute solution formed after absorbing water vapor is sent to the steam treatment device, and the water is evaporated by heating the lithium bromide dilute solution to obtain a lithium bromide concentrated solution again, and then the lithium bromide concentrated solution is sent back to the evaporator 13 for recycling. According to the selected working medium, the steam of the working medium is absorbed by an appropriate absorption medium, and then after steam treatment, the steam or liquid of the working medium is sent to the pressure generator for circulation.

[0055] In addition, in this embodiment, the working fluid can be a single working fluid, that is, one working fluid; or two or more working fluids can be used, and the saturated vapor pressures and vaporization temperatures of the multiple working fluids are different. Moreover, the multiple working fluids can be fully mixed with each other, or one or more working fluids can be soluble in another working fluid.

[0056] When two working fluids are used, using multiple working fluids has the following advantages:

[0057] First, when the working medium is heated in the evaporator, the working medium with a low vaporization temperature is easy to generate steam and form high-pressure steam. Therefore, steam can be generated at a relatively low temperature, thereby reducing the power consumption of the pressure generator and obtaining a higher steam pressure at the same temperature, which is conducive to improving the ability of the liquid medium to do work. When the liquid medium is completely pushed out of the pressure generator, the heat exchanger in the pressure generator can be used to cool the steam medium and condense it into a liquid medium.

[0058] Secondly, the working fluid with high saturated vapor pressure is easy to evaporate and vaporize in the evaporator, which is conducive to returning the working fluid to the pressure generator and absorbing the heat of the low-temperature heat source.

[0059] Third, when one working medium is dissolved in another working medium, the solubility will decrease when the temperature rises, and the dissolved working medium will easily precipitate in the form of gas, pushing the liquid working medium to do work. When the liquid working medium is completely pushed out of the pressure generator, the heat exchanger in the pressure generator can be used to cool the steam working medium. As the temperature and pressure drop, the solubility is restored, and the steam working medium is quickly dissolved in the liquid working medium, thereby maintaining the continuous work of the pressure generator. When the dissolved working medium is heated again, it is prepared for the next working cycle.

[0060] The working fluid can also be a solute working fluid that is easily soluble in the solvent. When the temperature and pressure increase, the solubility decreases, and the working fluid precipitates from the solvent working fluid to form steam. For example, ammonia and water, ammonia is very soluble in water. When the temperature and pressure increase, the solubility of ammonia in water decreases, ammonia precipitates from the water, and forms ammonia gas on the water surface. The ammonia gas pressure can push the liquid working fluid water to do work. After the liquid working fluid in the pressure generator has flowed out, the heat exchanger in the pressure generator is used to cool the high-temperature gaseous ammonia in the pressure generator. After the temperature of the ammonia is reduced, the liquid working fluid water is introduced so that the ammonia can quickly blend into the liquid water and prepare to start the next working cycle.

[0061] Therefore, as a variant embodiment of this embodiment, the working medium includes a first working medium and a second working medium, and the first working medium is soluble in the second working medium; the gaseous second working medium is dissolved in the liquid or gaseous steam absorbing medium to reduce the pressure in the evaporator 3. Specifically, the first working medium can be vaporized when heated to a lower temperature, but the steam of the first working medium is easily dissolved in the second working medium at room temperature or lower temperature and pressure. When the pressure generator 1 heats the first working medium and the second working medium, the first working medium is vaporized first, increasing the pressure in the pressure generator 1, thereby pushing the liquid second working medium, or most of the liquid second working medium and part of the first working medium into the working device to do work. In the evaporator, the steam of the first and second working mediums is absorbed by the steam absorbing medium, thereby reducing the pressure in the evaporator 3.

[0062] In addition, when a higher temperature heat source is not provided in the pressure generator 11, a heat storage device is provided. Taking the working fluid R134A as an example, the latent heat of evaporation of R134A is 216 kj / kg, and the specific heat capacity of liquid R134a is 1.51 kj / kg. If the gaseous 134a is condensed into a liquid state, the temperature of the same mass of liquid will be increased by about 143 degrees. When the high-temperature and high-pressure steam working fluid generated by the evaporator 13 enters the pressure generator 11, the temperature of the liquid working fluid in the pressure generator 11 will be greatly increased, that is, the latent heat of vaporization of the R134a working working fluid can be used to increase the temperature of the liquid working fluid. However, the temperature difference between the high-temperature and high-pressure steam compressed by the steam compression device and the low-temperature heat source of the environment is much less than 143 degrees, which also means that part of the working working fluid steam cannot be condensed into liquid, so a heat storage device is required to temporarily absorb the condensation heat of this part of the working working fluid that cannot be condensed and temporarily store it.

[0063] When the working device 12 is not required to work, the liquid working fluid flowing out of the working device 12 no longer passes through the evaporator 13 but directly enters the pressure generator 11. At this time, since the working fluid does not pass through the evaporator 13, the liquid working fluid can only be cooled to room temperature, and the pressure difference between the working fluid inlet and the working fluid outlet of the working device 12 is small. With such a cycle, the waste heat in the working system can be used as much as possible until the temperature of the liquid working fluid is reduced to a level that it can no longer work, thereby converting the waste heat into electrical energy or other energy storage. Alternatively, the liquid working fluid flowing out of the working device 12 passes through the evaporator 13, but the working fluid vapor in the evaporator is not processed to keep the vapor pressure unchanged. In this way, the liquid working fluid that has completed the work passes through the evaporator 13, but does not undergo an evaporation process in the evaporator 13 and directly enters the pressure generator.

[0064] Example 2

[0065] like Figure 3As shown, the working medium cycle working system provided in Example 2 includes a pressure generator 11, a working device 12, an evaporator 13, a steam compression device 14, a first heat exchanger 15 and a second heat exchanger 16, and the pressure generator 11, the first heat exchanger 15, the working device 12, the second heat exchanger 16, the evaporator 13 and the steam compression device 14 are connected end to end in sequence through pipelines, that is, the working medium outlet of the pressure generator 11 is connected to the working medium inlet of the first heat exchanger 15, and the working medium outlet of the first heat exchanger 15 is connected to the working device 12. The working fluid inlet of the working device 12 is connected, the working fluid outlet of the working device 12 is connected to the working fluid inlet of the second heat exchanger 16, the working fluid outlet of the second heat exchanger 16 is connected to the working fluid inlet of the evaporator 13, the working fluid outlet of the evaporator 13 is connected to the working fluid inlet of the steam compression device 14, and the working fluid outlet of the steam compression device 14 is connected to the working fluid inlet of the pressure generator 11, so that the working working fluid circulates in the pressure generator 11, the first heat exchanger 15, the working device 12, the second heat exchanger 16, the evaporator 13 and the steam compression device 14.

[0066] When the temperature of the working medium entering the working device 12 is high, that is, when the temperature of the liquid medium output by the pressure generator 11 is high, as the work is performed, the pressure of the liquid medium will often be lower than the saturated vapor pressure corresponding to its own temperature, and the liquid medium will generate steam. If the liquid medium generates steam in the working device 12, cavitation and other phenomena will occur, which will damage the working device 12 and reduce the service life of the working device 12. The first heat exchanger 15 can reduce the temperature of the liquid medium entering the working device 12 so that the liquid medium does not generate steam in the working device 12. At the same time, it can increase the pressure difference between the pressure generator 11 and the working medium outlet of the working device 12, so that the working device obtains greater driving force. The first heat exchanger preferably adopts two-stage heat exchange, the first stage of heat exchange is to cool the high-temperature liquid medium to ambient temperature; the second stage of heat exchange is to cool the liquid medium from ambient temperature to a lower temperature by cooling. The cooling capacity of the first heat exchanger 15 preferably comes from the evaporator 13, that is, the low-temperature liquid working medium generated by the evaporator 13 is used to reduce the temperature of the liquid working medium entering the working device 12, so that the temperature of the liquid working medium entering the working device 12 can be reduced while the temperature of the liquid working medium entering the pressure generator 11 can be increased. That is to say, the working medium circulation working system of this embodiment is configured as follows: first, the low-temperature liquid working medium output from the evaporator 13 is transmitted to the first heat exchanger 15 through a pipeline, and then the low-temperature liquid working medium is transmitted to the pressure generator 11 through a pipeline, so that the temperature of the liquid working medium input to the working device 12 is reduced, and the damage of the liquid working medium to the working device 12 is reduced, and the heat is recycled, the temperature of the liquid working medium entering the pressure generator 11 is increased, and energy consumption is reduced, and energy is saved.

[0067] Since the temperature of the liquid working medium output from the working device 12 is relatively low, the second heat exchanger 16 is arranged between the working device 12 and the evaporator 13 to increase the temperature of the liquid working medium entering the evaporator 13. The heat of the second heat exchanger 16 can come from a low-temperature heat source, which refers to air, rivers, lakes, and seas, and absorbs heat from these low-temperature heat sources; or utilizes the heat in the high-temperature and high-pressure steam working medium generated by the evaporator 13.

[0068] As a variant embodiment of the present embodiment, the working fluid circulation working system further includes a steam treatment device, that is, the steam treatment device replaces the steam compression device, and a steam absorption working fluid is arranged in the evaporator 13, and the steam absorption working fluid absorbs the steam of the working working fluid to reduce the pressure of the steam in the evaporator 13, and the absorbed working working fluid is transported to the steam treatment device together with the steam absorption working fluid, so that the working working fluid and the steam absorption working fluid are separated, and the working working fluid is returned to the pressure generator 11 in the form of liquid or steam.

[0069] In this variant embodiment, the steam treatment medium of the steam medium is not a medium for doing work, so it does not participate in doing work, but is only used to treat the medium for doing work. For example, the steam absorption medium uses a concentrated lithium bromide solution, and the working medium uses water. The concentrated lithium bromide solution has a strong ability to absorb water vapor. When the water vapor contacts the concentrated lithium bromide solution in the evaporator 13, the water vapor in the evaporator 13 enters the concentrated lithium bromide solution, causing the water vapor pressure in the evaporator 13 to decrease and the water to continue to evaporate; the concentrated lithium bromide solution absorbs the water vapor and becomes a dilute solution and then flows out of the evaporator 13. Heating the dilute lithium bromide solution can evaporate the water into water vapor, and obtain a concentrated lithium bromide solution again; the water vapor is then sent back to the pressure generator 11 in the form of steam or high-temperature condensed water.

[0070] The other structures, connection methods and functions of the working medium circulation system provided in Example 2 are the same as those in Example 1 and will not be described in detail here.

[0071] Example 3

[0072] like Figure 4As shown, the working medium cycle power system provided in Example 3 includes four pressure generators 11a, 11b, 11c, 11d, a power device 12, an evaporator 13, a steam compression device 14, a first heat exchanger 15 and a second heat exchanger 16, and the pressure generator 11, the first heat exchanger 15, the power device 12, the second heat exchanger 16, the evaporator 13 and the steam compression device 14 are connected end to end in sequence through pipelines, that is, the pressure generators 11a, 11b, 11c, 11d are arranged in parallel, and the pressure generators 11a, 11 The working fluid outlets of the first heat exchanger 15 are connected to the working fluid inlet of the working device 12, the working fluid outlet of the working device 12 is connected to the working fluid inlet of the second heat exchanger 16, the working fluid outlet of the second heat exchanger 16 is connected to the working fluid inlet of the evaporator 13, the working fluid outlet of the evaporator 13 is connected to the working fluid inlet of the steam compression device 14, and the working fluid outlet of the steam compression device 14 is connected to the working fluid inlet of the pressure generators 11a, 11b, 11c, 11d. The working fluid circulates in the pressure generators 11a, 11b, 11c, 11d, the first heat exchanger 15, the working device 12, the second heat exchanger 16, the evaporator 13 and the steam compression device 14.

[0073] The main feature of this embodiment is that four pressure generators 11a, 11b, 11c, and 11d are provided, and the four pressure generators 11a, 11b, 11c, and 11d cyclically receive the steam working medium and the liquid working medium output by the evaporator, and cyclically work on the working device 12, that is, only one pressure generator works on the working device 12 at the same time. In addition, when the pressure generators 11a, 11b, 11c, and 11d receive the liquid working medium output by the evaporator at a temperature lower than room temperature, the liquid working medium first absorbs heat from the low-temperature heat source.

[0074] Specifically, it is assumed that the initial states of the pressure generators 11a, 11b, 11c, and 11d are: the pressure generator 11a is filled with liquid working fluid with a relatively high temperature, and the liquid working fluid is heated by a heating source to increase the steam pressure therein; the working working fluid in the pressure generators 11b and 11c is liquid working fluid at room temperature, and the working working fluid in the pressure generator 11d is steam working fluid.

[0075] When the working system that can utilize the low-temperature heat source starts to operate, the pressure generator 11a works on the working device 12, and the steam compression device 14 compresses the steam working medium in the evaporator 13 and presses it to the pressure generator 11b, and uses the high-temperature and high-pressure steam working medium to heat the liquid working medium in the pressure generator 11b. When the temperature of the liquid working medium in the pressure generator 11b reaches the upper limit that the steam working medium can heat, the high-temperature and high-pressure steam working medium can be pressurized to the pressure generator 11c to heat the liquid working medium in the pressure generator 11c, and at the same time, the temperature of the liquid working medium in the pressure generator 11b is kept constant; the liquid working medium in the evaporator 13 that is lower than the room temperature is transported to the pressure generator 11d through the working medium pump. Since the temperature of the liquid working medium is relatively low at this time, it can absorb the heat in the low-temperature heat source and make the temperature of the liquid working medium the same as the temperature of the low-temperature heat source. When the liquid working medium in the pressure generator 11a is consumed, the heating source in the pressure generator 11b is started, so that the pressure generator 11b starts to work on the working device 12, and the steam working medium output by the evaporator 13 is pressed to the pressure generator 11c, and the liquid working medium in the pressure generator 11c is heated by the high-temperature and high-pressure steam working medium; at this time, the pressure generator 11d is already filled with liquid working medium, and the liquid working medium has reached the ambient temperature due to absorbing heat from the environment. When the temperature of the liquid working medium in the pressure generator 11c reaches the upper temperature limit, the high-temperature and high-pressure steam output by the evaporator 13 can be pressed to the pressure generator 11d while maintaining the temperature of the liquid working medium in the pressure generator 11c, so as to heat the temperature of the liquid working medium in the pressure generator 11c; the low-temperature liquid working medium output by the evaporator 13 is transmitted to the pressure generator 11a, and the low-temperature liquid working medium in the pressure generator 11a continuously absorbs heat from the environment.

[0076] The four pressure generators 11a, 11b, 11c, and 11d circulate repeatedly in this way, and the low-temperature liquid working fluid output by the evaporator 13 continuously absorbs heat from the low-temperature heat source in the environment and reaches the ambient temperature, and then is heated by the high-temperature and high-pressure steam working fluid output by the evaporator 13. Finally, the heating source is used to increase the pressure of the steam working fluid to do work, which effectively utilizes the low-temperature heat source and reduces energy consumption, and recycles the heat in the high-temperature and high-pressure steam working fluid output by the evaporator 13, saving energy.

[0077] As a variant embodiment of this embodiment, the working system that can utilize the low-temperature heat source includes four pressure generators 11a, 11b, 11c, 11d, two working devices 12, an evaporator 13, and a steam compression device 14. The two working devices 12 are arranged in parallel, and the four pressure generators 11a, 11b, 11c, 11d circulate work on the two working devices 12. The two working devices 12 output the working medium to the evaporator 13, or one working device outputs the working medium to the evaporator 13, and the other working device directly outputs the working medium to the pressure generator without passing through the evaporator 13, so as to consume the condensation heat after steam compression as much as possible and reduce the burden on the heat storage device. The remaining steps and the cycle of the working medium are the same as those in other embodiments and will not be repeated here.

[0078] Example 4

[0079] like Figure 5 As shown, the working system that can utilize the low-temperature heat source provided in Example 4 includes two working fluid circulation working systems. For the convenience of description, the two working fluid circulation working systems are respectively referred to as the upper-level working fluid circulation working system and the lower-level working fluid circulation working system. Correspondingly, the pressure generator, working device, evaporator and steam compression device provided in the upper-level working fluid circulation working system are referred to as the upper-level pressure generator 11a, the upper-level working device 12a, the upper-level evaporator 13a and the upper-level steam compression device 14a; the pressure generator, working device, evaporator and steam compression device provided in the lower-level working fluid circulation working system are referred to as the lower-level pressure generator 11b, the lower-level working device 12b, the lower-level evaporator 13b and the lower-level steam compression device 14b.

[0080] The specific structure of the work system that can utilize a low-temperature heat source provided in Example 4 is as follows:

[0081] In the upper working medium cycle working system, the upper pressure generator 11a, the upper working device 12a, the upper evaporator 13a and the upper steam compression device 14a are connected end to end in sequence through pipelines; in the lower working medium cycle working system, the lower pressure generator 11b, the lower working device 12b, the lower evaporator 13b and the lower steam compression device 14b are connected end to end in sequence through pipelines. The specific connection method and function of the upper working medium cycle working system and the lower working medium cycle working system are the same as those in Example 2, and will not be repeated here. In addition, the liquid working medium outlet of the upper evaporator 13a and the working medium outlet of the lower steam compression device 14b are arranged in a heat exchange manner, so as to utilize the heat of the high-temperature and high-pressure steam working medium output by the lower steam compression device 14b to heat the temperature of the upper low-temperature liquid working medium, and at the same time, the lower steam working medium is condensed.

[0082] It should be pointed out that although the working system that can utilize the low-temperature heat source provided in Example 4 is provided with two working fluid circulation working systems, the present invention is not limited to this. In fact, the working system that can utilize the low-temperature heat source can also be provided with more than two working fluid circulation working systems of any number. Specifically, the working system that can utilize the low-temperature heat source includes n-stage working fluid circulation working systems, and the n-stage working fluid circulation working systems are connected step by step, that is, the upper-stage evaporator 13a and the lower-stage steam compression device 14b are arranged in a heat exchange manner, wherein n is a positive integer greater than or equal to 2, so as to circulate the heat in the working fluid. The working fluid circulation working systems can utilize heat and cold energy to perform corresponding heating and cooling.

[0083] Example 5

[0084] like Figure 6 As shown, the working system that can utilize a low-temperature heat source provided in Example 5 includes a working fluid circulation working system and a steam working device.

[0085] The structure of the working medium cycle working system is the same as that of the working medium cycle working system in Example 1, which includes a pressure generator 11, a working device 12 and an evaporator 13, and the pressure generator 11, the working device 12 and the evaporator 13 are connected end to end in sequence through pipelines.

[0086] The steam working device adopts the steam working device currently available on the market, which includes a steam working system pressure generator 61, a steam working system working device 62 and a steam working system working fluid pump 63. The steam working system pressure generator 61, the steam working system working device 62 and the steam working system working fluid pump 63 are connected end to end in sequence through pipelines. The working fluid outlet of the steam working device pressure generator 61 is connected to the working fluid inlet of the steam working system working device 62, the working fluid outlet of the steam working system working device 62 is connected to the input port of the working fluid pump 63, and the output port of the steam working system working fluid pump 63 is connected to the working fluid inlet of the steam working system pressure generator 61. The working fluid circulates in the steam working system pressure generator 61, the steam working system working device 62 and the steam working system working fluid pump 63, and the steam working system working fluid pump 63 provides power for the circulation of the working fluid.

[0087] The working fluid inlet of the pressure generator 11 and the working fluid outlet of the steam working system working device 62 are arranged in a heat exchange manner, that is, the high-temperature steam working fluid discharged from the steam working system working device 62 exchanges heat with the low-temperature liquid working fluid at the working fluid inlet of the pressure generator 11. On the one hand, the low-temperature liquid working fluid at the working fluid inlet of the pressure generator 11 is heated, which is conducive to the generation of high pressure in the pressure generator 11; on the other hand, the high-temperature steam working fluid discharged from the steam working system working device 62 is cooled, condensed into liquid, and then transported to the pressure generator 61 of the steam working system by the working pump 63, and the heat released by the condensation is utilized, saving energy.

[0088] Example 6

[0089] like Figure 7 As shown, the working system that can utilize a low-temperature heat source provided in Example 6 includes a working fluid circulation working system and a steam working device.

[0090] Specifically, the working system that can utilize the low-temperature heat source includes a pressure generator 11, a working device 12, an evaporator 13, a steam working system pressure generator 61 and a steam working system working device 62, and the steam working system pressure generator 61, the steam working system working device 62, the pressure generator 11, the working device 12 and the evaporator 13 are connected end to end in sequence through pipelines, that is, the working fluid outlet of the steam working system pressure generator 61 is connected to the working fluid inlet of the steam working system working device 62, the working fluid outlet of the steam working system working device 62 is connected to the working fluid inlet of the pressure generator 11, the working fluid outlet of the pressure generator 11 is connected to the working fluid inlet of the working device 12, the working fluid outlet of the working device 12 is connected to the working fluid inlet of the evaporator 13, and the working fluid outlet of the evaporator 13 is connected to the working fluid inlet of the steam working system pressure generator 61. The steam working medium discharged from the working device 62 of the steam working system directly enters the pressure generator 11 and serves as a high-temperature heat source to heat the liquid working medium in the pressure generator 11 .

[0091] The high-temperature liquid working medium discharged between the pressure generator 11 and the working device 62 is returned to the steam working system pressure generator 61, which effectively utilizes the heat of the high-temperature liquid working medium and reduces the energy consumption of the steam working system.

[0092] Example 7

[0093] like Figure 8 As shown, the working system that can utilize a low-temperature heat source provided in Example 7 includes a working fluid circulation working system and a steam working device.

[0094] The structure of the working fluid cycle working system is the same as that of the working fluid cycle working system in Example 2, which includes a pressure generator 11, a working device 12, an evaporator 13 and a steam compression device 14, and the pressure generator 11, the working device 12, the evaporator 13 and the steam compression device 14 are connected end to end in sequence through pipelines.

[0095] The steam working device adopts the steam working device currently available on the market, which includes a steam working system pressure generator 61, a steam working system working device 62 and a steam working system working fluid pump 63. The steam working system pressure generator 61, the steam working system working device 62 and the steam working system working fluid pump 63 are connected end to end in sequence through pipelines. The working fluid outlet of the steam working device pressure generator 61 is connected to the working fluid inlet of the steam working system working device 62, the working fluid outlet of the steam working system working device 62 is connected to the input port of the working fluid pump 63, and the output port of the steam working system working fluid pump 63 is connected to the working fluid inlet of the steam working system pressure generator 61, so that the working fluid circulates in the steam working system pressure generator 61, the steam working system working device 62 and the steam working system working fluid pump 63, and the steam working system working fluid pump 63 provides power for the circulation of the working fluid.

[0096] The evaporator 13 and the working medium outlet of the steam working system working device 62 are arranged in a heat exchange manner, so that the low-temperature liquid working medium output by the evaporator 13 is used to cool the steam working medium discharged from the steam working system working device 62, and at the same time, the temperature of the low-temperature liquid working medium output by the evaporator 13 is heated. In addition, the steam compression device 14 and the steam working system pressure generator 61 are arranged in a heat exchange manner, and the high-temperature and high-pressure steam working medium output by the steam compression device 14 is used to increase the temperature of the working medium in the steam working system pressure generator 61.

[0097] The evaporator 13 of this embodiment utilizes the waste heat output by the steam working device, reduces the temperature of the working medium entering the steam working system working medium pump 63, and reduces the damage to the steam working system working medium pump 63. At the same time, the steam working system pressure generator 61 utilizes the heat of the high-temperature and high-pressure steam working medium output by the steam compression device 14, which is beneficial to improving the working efficiency of the steam working device.

[0098] Example 8

[0099] like Fig. 9 As shown, the working system that can utilize a low-temperature heat source provided in Example 8 includes a working fluid circulation working system and a refrigeration system.

[0100] The refrigeration system includes a refrigeration system evaporator 71, a refrigeration system condenser 72 and a refrigeration system compressor 73, and the refrigeration system evaporator 71, the refrigeration system condenser 72 and the refrigeration system compressor 73 are connected end to end in sequence, that is, the working fluid outlet of the refrigeration system evaporator 71 is connected to the working fluid inlet of the refrigeration system compressor 73, the working fluid outlet of the refrigeration system compressor 73 is connected to the working fluid inlet of the refrigeration system condenser 72, and the working fluid outlet of the refrigeration system condenser 72 is connected to the working fluid input port of the refrigeration system evaporator 71. The refrigeration system evaporator 71 absorbs heat to evaporate the refrigerant, the refrigeration system compressor 73 presses the refrigerant to the refrigeration system condenser 72, and the refrigeration system condenser 72 dissipates heat to cool the refrigerant.

[0101] The structure of the working fluid cycle working system is the same as that of the working fluid cycle working system in Example 2, which includes a pressure generator 11, a working device 12, an evaporator 13 and a steam compression device 14, and the pressure generator 11, the working device 12, the evaporator 13 and the steam compression device 14 are connected end to end in sequence through pipelines.

[0102] In addition, the refrigeration system evaporator 71 and the vapor compression device 14 are arranged in a heat exchange manner. Since the evaporating refrigerant in the refrigeration system evaporator 71 needs to absorb heat, the heat in the high-temperature and high-pressure steam working medium output by the vapor compression device 14 can provide heat for the refrigeration system evaporator 71, and the heat in the vapor compression device 14 is utilized, which is conducive to reducing heat loss. Moreover, the refrigeration system condenser 72 and the pressure generator 11 are arranged in a heat exchange manner. The refrigeration system condenser 72 will release a large amount of heat in the refrigerant during the condensation process, and this heat can be used by the pressure generator 11 to increase the temperature of the liquid working medium in the pressure generator 11.

[0103] In Embodiments 1 to 8, the working system that can utilize a low-temperature heat source further includes an energy storage device, the energy input end of the energy storage device is connected to the energy output end of the working device, and is used to store the energy output by the working device. When the electric energy required by the user decreases, the electric energy generated by the working device can be stored with the help of the energy storage device; or, the energy storage device is used to store heat.

[0104] Since the latent heat of vaporization of the working fluid is very high, in addition to partially condensing the steam to transfer the heat to the liquid working fluid, the condensed working fluid must first absorb the latent heat of vaporization of the high-temperature and high-pressure working fluid to completely liquefy the working fluid vapor. These higher-temperature condensed working fluids are first stored in the energy storage device, and when the work requirements are low, they are directly returned to the pressure generator without passing through the evaporator; or they pass through the evaporator, but the steam of the working fluid is not processed, and the vapor pressure of the working fluid in the evaporator is maintained, so that the liquid working fluid no longer evaporates and all flows into the pressure generator. This method can consume the heat of the condensed working fluid of the energy storage device, but the working power will be reduced. The purpose of setting the working device in parallel in Example 4 is also to reduce this part of the heat and reduce the burden on the energy storage device.

[0105] The above-mentioned embodiment provides a working system that can utilize a low-temperature heat source. When the working medium evaporates in the evaporator, it can produce a low-temperature liquid medium and a high-temperature steam medium that are lower than room temperature. The low-temperature liquid medium can absorb the heat in the low-temperature heat source in the pressure generator or before entering the pressure generator, so that its temperature reaches the temperature of the low-temperature heat source. This can reduce the energy consumed by the pressure generator when vaporizing the liquid medium. In addition, in the pressure generator, the low-temperature liquid medium can use the heat in the high-temperature steam medium output by the evaporator to increase its temperature or vaporize the liquid medium, thereby recycling the heat. Therefore, the working system not only utilizes low-temperature heat sources in environments such as air, rivers, lakes, and seas, expanding the range of energy sources, but also recycles the heat in the steam medium generated by the evaporator, saving energy.

[0106] Example 9

[0107] like Fig.10 As shown, this embodiment provides a method for performing work using a low-temperature heat source. The method is based on the work-performing system provided in Embodiments 1 to 8, and the method includes the following steps:

[0108] Step S1, heating the liquid working medium in the pressure generator to vaporize it and increase the pressure of the steam in the pressure generator to pressurize the liquid working medium to the working device;

[0109] Step S2, the liquid working medium is pressed to the evaporator after completing work in the working device;

[0110] In step S3, the liquid working medium is vaporized in the evaporator to obtain the steam working medium. Meanwhile, the steam working medium is absorbed by the steam absorption working medium in the evaporator and discharged from the evaporator.

[0111] Step S4, separating the steam working medium from the steam absorption working medium, and returning the separated steam working medium to the pressure generator, while returning the steam absorption working medium to the evaporator.

[0112] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A work system that can utilize a low-temperature heat source, characterized in that: The working system that can utilize the low-temperature heat source includes a working medium circulation working system, and the working medium circulation working system includes a pressure generator, a working device and an evaporator, and the pressure generator, the working device and the evaporator are connected end to end in sequence to allow the working medium to circulate; the evaporator obtains steam working medium and liquid working medium below room temperature in the process of vaporizing the working working medium, and the liquid working medium below room temperature absorbs heat from the low-temperature heat source before or after returning to the pressure generator, and the steam working medium returns to the pressure generator to heat the liquid working medium and increase the steam pressure in the pressure generator, so as to drive the liquid working medium to do work in the working device; The working fluid includes a first working fluid and a second working fluid, which have different saturated vapor pressures and vaporization temperatures; the first working fluid is dissolved in the second working fluid, and when the pressure generator heats the first working fluid and the second working fluid, the first working fluid vaporizes first, increasing the pressure in the pressure generator, thereby pushing the liquid second working fluid, or most of the liquid second working fluid and part of the first working fluid into the working device to do work.

2. The work system capable of utilizing a low temperature heat source according to claim 1, characterized in that: The working medium cycle work system further comprises a steam compression device, which is connected in series between the evaporator and the pressure generator, and the steam compression device sucks the steam working medium generated by the evaporator and compresses it to reduce the pressure of the steam in the evaporator, and then compresses the compressed steam working medium to the pressure generator; Alternatively, the working fluid circulation working system also includes a steam processing device, and a steam absorbing working fluid is provided in the evaporator, and the steam absorbing working fluid absorbs the steam of the working working fluid to reduce the pressure of the steam in the evaporator, and the absorbed working working fluid is transported to the steam processing device together with the steam absorbing working fluid to separate the working working fluid from the steam absorbing working fluid, and the working working fluid is returned to the pressure generator in the form of liquid or steam.

3. The work system capable of utilizing a low temperature heat source according to claim 2, characterized in that: The work system that can utilize a low-temperature heat source includes n-stage working medium circulation work systems connected step by step, and the evaporator of the previous stage and the steam compression device of the next stage are arranged in a heat exchange manner, wherein n is a positive integer greater than or equal to 2.

4. The work system capable of utilizing a low temperature heat source according to claim 2, characterized in that: The working system that can utilize the low-temperature heat source also includes a steam working system, and the steam working system includes a steam working system pressure generator, a steam working system working device and a steam working system working fluid pump, and the steam working system pressure generator, the steam working system working device and the steam working system working fluid pump are connected end to end in sequence; Furthermore, the pressure generator of the steam working system is arranged in a heat exchange manner with the steam compression device of the working medium cycle working system, and the working device of the steam working system is arranged in a heat exchange manner with the evaporator of the working medium cycle working system; Alternatively, the working device of the steam working system and the pressure generator of the working medium cycle working system are arranged in a heat exchange manner.

5. The work system capable of utilizing a low temperature heat source according to claim 2, characterized in that: The working system that can utilize a low-temperature heat source also includes a steam working system, and the steam working system includes a steam working system pressure generator and a steam working system working device. The steam working system pressure generator, the steam working system working device, the pressure generator, the working device and the evaporator are connected end to end in sequence, and the working fluid outlet of the pressure generator is connected to the working fluid inlet of the steam working system pressure generator, and the working fluid outlet of the evaporator is connected to the working fluid inlet of the pressure generator.

6. The work system capable of utilizing a low-temperature heat source according to any one of claims 1 to 5, characterized in that: The working system that can utilize a low-temperature heat source includes a plurality of the pressure generators and a plurality of working devices arranged in parallel. The plurality of pressure generators receive the liquid working medium and the steam working medium output by the evaporator in a cycle in sequence. The plurality of working devices are arranged in parallel and perform work in a cycle.

7. The work system capable of utilizing a low-temperature heat source according to any one of claims 1 to 5, characterized in that: A heating source is arranged in the pressure generator to increase the steam pressure in the pressure generator.

8. The work system capable of utilizing a low-temperature heat source according to any one of claims 1 to 5, characterized in that: The working fluid circulation working system also includes a first heat exchanger and / or a second heat exchanger, wherein the working fluid inlet of the first heat exchanger is connected to the working fluid outlet of the pressure generator, and the working fluid outlet of the first heat exchanger is connected to the working fluid inlet of the working device, and the first heat exchanger is used to reduce the temperature of the working fluid entering the working device; the working fluid inlet of the second heat exchanger is connected to the working fluid outlet of the working device, and the working fluid outlet of the second heat exchanger is connected to the working fluid inlet of the evaporator, and the second heat exchanger is used to increase the temperature of the working fluid entering the evaporator.

9. A method for using a low temperature heat source to perform work, characterized in that: The method is based on the working system according to any one of claims 1 to 8, and the method comprises the following steps: Step S1, heating the liquid working medium in the pressure generator to vaporize it and increase the pressure of the steam in the pressure generator to pressurize the liquid working medium to the working device; Step S2, the liquid working medium is pressed to the evaporator after completing work in the working device; Step S3, the liquid working medium is vaporized in the evaporator to obtain steam working medium, and at the same time, the steam working medium is absorbed by the steam absorption working medium in the evaporator and discharged from the evaporator; Step S4, separating the steam working medium from the steam absorption working medium, and returning the separated steam working medium to the pressure generator, while returning the steam absorption working medium to the evaporator.

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