CN107587907A - A kind of working system and method using low-temperature heat source - Google Patents

Abstract

The invention discloses a kind of working system and method using low-temperature heat source.This includes working medium circulation working system using the working system of low-temperature heat source, the working medium circulation working system includes pressure generator, acting device and evaporator, and the pressure generator, acting device connect for acting working medium circulation flowing from beginning to end successively with evaporator；The evaporator obtains steam working medium and the liquid working substance less than room temperature during the acting working medium is vaporized, the liquid working substance less than room temperature absorbs the heat of low-temperature heat source before or after the pressure generator is returned, the steam working medium returns to the heating liquid working substance in the pressure generator and lifts the steam pressure in the pressure generator, to promote liquid working substance to be done work in the acting device.This can utilize the low-temperature heat source in environment using the working system of low-temperature heat source, reduce energy consumption and save the energy.

Description

A work system and method that can utilize a low-temperature heat source

technical field

The invention relates to the technical field of cycle work or power generation, in particular to a work system and method that can utilize a low-temperature heat source.

Background technique

So far, most of the devices that do work or generate electricity use the expansion of high-temperature and high-pressure gas to do work or generate electricity. 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 medium, such as water, through fuel combustion to evaporate the liquid working medium to form high-temperature and high-pressure gas, such as internal combustion engines, Gas turbines, steam engines, etc.

The method of directly obtaining high-temperature and high-pressure gas through fuel combustion requires high temperature and pressure of the gas. When the temperature and pressure of the gas 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. .

The liquid working medium is heated by heating, so that the liquid working medium evaporates into a high-temperature and high-pressure gas, and the gas working medium does work. After the gas working medium does work, the temperature and pressure drop very low. It is difficult to directly recycle and reuse the gas working medium. Liquefied into a liquid working medium, the liquid working medium is heated into a 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.

In addition, most of the current refrigeration systems use the compressor to compress the vapor of the refrigerant, which causes the vapor pressure in the evaporator to decrease, and promotes the evaporation of the refrigerant 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 condensed working fluid. During this process, not only a large amount of low-temperature heat energy is lost, but also a large amount of cooling water is lost.

To sum up, on the one hand, the existing work devices and power generation devices waste a lot of low-temperature heat energy, and on the other hand, they cannot utilize a large number of existing low-temperature heat sources or waste heat.

Contents of the invention

The object of the present invention is to provide a work system and method that can utilize low-temperature heat sources to solve the problems of waste of low-temperature heat energy and inability to utilize low-temperature heat sources.

In order to achieve the above object, the technical solution of the present invention is to provide a work system that can utilize a low-temperature heat source, the work system that can use a low-temperature heat source includes a working fluid circulation system, and the working medium circulation work system includes a pressure generator, The working device and the evaporator, the pressure generator, the working device and the evaporator are sequentially connected end to end for the circulation of the working medium; the evaporator obtains steam working medium and lower than room temperature The liquid working medium below room temperature absorbs the heat of 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 lift The steam pressure in the pressure generator is used to push the liquid working medium to do work in the work device.

Preferably, the working fluid circulation system further includes a vapor compression device connected in series between the evaporator and the pressure generator, and the vapor compression device converts the vapor generated by the evaporator compressing the working medium to reduce the pressure of the steam in the evaporator, and sending the compressed working medium to the pressure generator;

Alternatively, the working medium circulation system also includes a steam treatment device, and the vapor absorbing working medium is arranged in the evaporator, and the steam absorbing working medium absorbs the steam of the working medium to reduce the steam in the evaporator. steam pressure, the absorbed working medium and the steam absorption working medium are transported to the steam processing device, so that the working medium is separated from the steam absorption working medium, and the working medium is Liquid or steam is returned to the pressure generator.

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

Preferably, 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, a steam working system working device and a steam working system working medium pump, and the steam working system pressure The generator, the work device of the steam work system and the working medium pump of the steam work system are connected in sequence from end to end;

In addition, the pressure generator of the steam work system and the steam compression device of the working medium circulation work system are arranged in a heat exchange manner, and the work device of the steam work system is heat exchanged with the evaporator of the work medium circulation work system mode setting;

Alternatively, the working device of the steam working system and the pressure generator of the working fluid circulation working system are arranged in a heat exchange manner.

Preferably, the steam work system, the steam work system includes a steam work system pressure generator and a steam work system work device, the steam work system pressure generator, the steam work system work device, the pressure generator, the work The device and the evaporator are connected end to end in sequence, so that the working medium circulates in the pressure generator of the steam work system, the work device of the steam work system, the pressure generator, the work device and the evaporator in sequence , and, the working medium outlet of the pressure generator communicates with the working medium inlet of the steam power system pressure generator, and the working medium outlet of the evaporator communicates with the working medium inlet of the pressure generator.

Preferably, the work system that can utilize a low-temperature heat source includes a plurality of pressure generators and a plurality of work devices arranged in parallel, and the plurality of pressure generators sequentially receive the liquid output from the evaporator in a cycle The working medium, the steam working medium, and a plurality of the work-making devices are arranged in parallel to perform work in a cycle.

Preferably, a heating source is provided in the pressure generator, and when the pressure generator receives the liquid working medium below room temperature, the liquid working medium first absorbs the heat in the low-temperature heat source and then is heated by the Source heating to increase the vapor pressure within the pressure generator.

Preferably, the working substance includes a first working substance and a second working substance, and the first working substance can be mixed with the second working substance, or dissolved in the second working substance; In the evaporator, the working medium steam is absorbed by the steam absorbing working medium, reducing the vapor pressure of the working medium in the evaporator, and the absorbed working medium steam is transported to the steam processing device together with the steam absorbing working medium , to separate the steam from the steam absorbing working medium, and return to the pressure generator in the form of liquid or steam.

Wherein, the working fluid circulation system further includes a first heat exchanger and/or a second heat exchanger, the working fluid inlet of the first heat exchanger communicates with the working fluid outlet of the pressure generator, and the The working medium outlet of the first heat exchanger communicates with the working medium inlet of the work device, and the first heat exchanger is used to reduce the temperature of the working medium entering the work device; the second heat exchanger The working fluid inlet of the working fluid is connected with the working fluid outlet of the work device, the working fluid outlet of the second heat exchanger is connected with the working fluid inlet of the evaporator, and the second heat exchanger is used to improve the evaporator The temperature of the working medium of the device.

Preferably, the work system that can utilize a low-temperature heat source further includes an energy storage device connected to the energy output end of the work device for storing the energy output by the work device.

The present invention also provides a method that can use a low-temperature heat source to perform work. The method provides the work system based on the present invention. The method includes the following steps:

Step S1, heating the liquid working medium in the pressure generator to vaporize it and increasing the pressure of the steam in the pressure generator, so as to pressurize the liquid working medium to the work device;

Step S2, the liquid working medium is sent to the evaporator by pressure after completing the work in the work device;

Step S3, the liquid working medium is vaporized in the evaporator to obtain a steam working medium, and at the same time, the steam working medium is absorbed by the vapor absorbing working medium in the evaporator and discharged from the evaporator;

Step S4, separating the steam working medium from the steam absorbing working medium, returning the separated steam working medium to the pressure generator, and returning the steam absorbing working medium to the evaporator at the same time .

The present invention has the following advantages:

The work system provided by the present invention can utilize a low-temperature heat source. When the working medium evaporates in the evaporator, it can produce a low-temperature liquid working medium and a steam working medium below room temperature. The generator absorbs the heat from the low-temperature heat source to make its temperature reach 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 make it vaporize. Energy consumption can be reduced, 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, so that the heat discharged from the evaporator can be recycled. Therefore, the working system not only utilizes low-temperature heat sources in the environment such as air, rivers, lakes, and seas to expand the range of energy sources, but also recycles the heat in the steam working medium generated by the evaporator to save energy.

Description of drawings

Fig. 1 is a schematic diagram of the connection relationship of the working medium circulation working system in the working system that can utilize low-temperature heat source provided by Embodiment 1 of the present invention;

Fig. 2 is a schematic diagram of the connection relationship of the working medium circulation working system in the working system that can utilize a low-temperature heat source provided by the preferred embodiment of embodiment 1 of the present invention;

Fig. 3 is a schematic diagram of the connection relationship of the working medium circulation working system in the working system that can utilize a low-temperature heat source provided by Embodiment 2 of the present invention;

Fig. 4 is a schematic diagram of the connection relationship of the working medium circulation working system in the working system that can utilize a low-temperature heat source provided by Embodiment 3 of the present invention;

Fig. 5 is a schematic diagram of the connection relationship between two working medium circulation systems in the work system that can utilize low-temperature heat sources provided by Embodiment 4 of the present invention;

Fig. 6 is a schematic diagram of the connection relationship between the working fluid system and the steam work device in the work system that can utilize a low-temperature heat source provided by Embodiment 5 of the present invention;

Fig. 7 is a schematic diagram of the connection relationship between the working fluid system and the steam work device in the work system that can utilize a low-temperature heat source provided by Embodiment 6 of the present invention;

Fig. 8 is a schematic diagram of the connection relationship between the working fluid system and the steam work device in the work system that can utilize a low-temperature heat source provided by Embodiment 7 of the present invention;

Fig. 9 is a schematic diagram of the connection relationship between the working medium system and the refrigeration system in the work system that can utilize low-temperature heat sources provided by Embodiment 8 of the present invention;

Fig. 10 is a flow chart of a method for performing work using a low-temperature heat source provided by Embodiment 9 of the present invention.

In the above drawings, the solid line represents the flow of the liquid working medium, the dotted line represents the flow of the vapor working medium, and the dotted line represents the heat exchange.

detailed description

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

Example 1

As shown in Figure 1, the working system that can utilize the low-temperature heat source provided by embodiment 1 includes a working medium circulation working system 1, and the working medium circulating working system 1 includes a pressure generator 11, a working device 12 and an evaporator 13, and the pressure generator 11 1, the work device 12 and the evaporator 13 are communicated end to end through pipelines successively, that is, the working medium outlet of the pressure generator 11 and the working medium inlet of the work device 12 are connected through the pipeline, and the working medium outlet of the work device 12 is connected with the working medium outlet of the evaporator 13. The inlet of the substance is communicated with the pipeline, the outlet of the working medium of the evaporator 13 is connected with the input port of the pressure generator 11 through the pipeline, and the working fluid circulates between the pressure generator 11, the power device 12 and the evaporator 13 through the pipeline. , the pressure difference of the working medium between the pressure generator 11 and the evaporator 13 provides power for the working device 12 to do work.

It should be noted that the working medium inlet of the pressure generator 11 includes a liquid working medium inlet and a steam working medium inlet, and the working medium outlet of the evaporator 13 includes a liquid working medium outlet and a steam working medium outlet. It is not difficult to understand that the liquid working medium outlet of the evaporator 13 communicates with the liquid working medium inlet of the pressure generator 11 correspondingly, and the steam working medium outlet of the evaporator 13 communicates with the steam working medium inlet of the pressure generator 11 correspondingly. For the convenience of description, the liquid working medium inlet and the steam working medium inlet of the pressure generator 11 are collectively referred to as the working medium inlet of the pressure generator 11 in most cases below, and the liquid working medium outlet and the steam working medium outlet of the evaporator 13 are collectively referred to as evaporation. The working medium outlet of device 13. Only when the liquid working medium and steam working medium are particularly emphasized, the expression of steam working medium inlet, steam working medium outlet, liquid working medium inlet or liquid working medium outlet is specially used.

The relatively high steam pressure that needs to be generated in the pressure generator 11 is used to pressurize the working medium into the work device 12 to do work, and then is pressurized to the evaporator 13 . However, when the temperature of the working medium is too high, it will adversely affect the life of the working device 12 , therefore, it is necessary to reduce the temperature of the working medium entering the working device 12 . That is to say, the working medium in the pressure generator 11 not only needs to absorb heat to increase the temperature and steam pressure of the working medium, but 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 two types: 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 back section needs to release heat to reduce the working medium to work Adverse Effects of Device 12.

The evaporator 13 is used to vaporize the working medium, and a large amount of heat needs to be absorbed when evaporating the working medium in the evaporator 13, so that the temperature of the non-vaporized liquid working medium is lowered below room temperature. The low-temperature liquid working medium can absorb heat from low-temperature heat sources, and the low-temperature heat sources referred to here include but not limited to air, rivers, lakes and seas.

In this embodiment, the evaporator 13 can 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 work device 12 communicates with the working medium inlet of the expansion device through a conduit, and the expansion device The working fluid outlet of the evaporator 13 communicates with the working fluid inlet of the evaporator 13 through a conduit. The expansion device can expand the working medium, so as to facilitate the evaporation and vaporization of the working medium in the evaporator 13 .

In this embodiment, a heat exchanger (not shown in the figure) is arranged in the pressure generator 11. When the working medium in the pressure generator 11 is lower than room temperature, the working medium absorbs the heat in the low-temperature heat source through the heat exchanger, And the temperature of working medium is raised to room temperature.

In addition, even if the low-temperature liquid working fluid absorbs the heat of the low-temperature heat source, the heat is not enough to make the working medium do work on the work 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 is used as a higher-temperature heat source to increase the temperature of the working medium and to vaporize the working medium. When the work device 12 needs to output a larger power, the heating source can increase the pressure of the steam working medium and increase the pressure. The pressure difference between the device 11 and the evaporator 13 enables the power device 12 to provide greater output power.

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, use the heating source to heat the heat-conducting medium, and then heat the working medium by the heat-conducting medium,

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 the heat exchanger and the heating source at the same time.

As a preferred embodiment of this embodiment, as shown in Figure 2, the working fluid circulation system also includes a vapor compression device 14, and the vapor compression device 14 is connected in series between the evaporator 13 and the pressure generator 11, that is, the vapor compression The working medium inlet of the device 14 communicates with the working medium outlet of the evaporator 13 through a pipeline, and the working medium outlet of the vapor compression device 14 communicates with the inlet of the pressure generator 11 through a pipeline. The vapor compression device 14 can compress the vapor working medium generated by the evaporator 13. On the one hand, it reduces the pressure of the vapor in the evaporator 13 and maintains the pressure in the evaporator 13 in a lower range, thereby increasing the pressure of the generator 11. The pressure difference between the evaporator and the evaporator 13, thereby improving the work efficiency of the work device; on the other hand, the high-temperature and high-pressure steam working medium is obtained, and the high-temperature and high-pressure steam working medium is sent to the pressure generator 11 to recycle its heat , reducing the waste of heat energy.

In this embodiment, the evaporator 13 is a flash tank evaporator, and the vapor working medium generated by the flash tank evaporator is compressed by the vapor compression device 14 and sent to the pressure generator 11, and the flash tank evaporator generates The cryogenic liquid working medium can be returned to the pressure generator 11 through a working medium pump (not shown in the figure). Before the cryogenic liquid working medium enters the pressure generator 11, it can absorb the heat in the environment to make it basically 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, Therefore, the energy required for the vaporization of the liquid working medium can be reduced.

It is not difficult to understand that the vapor compression device 14 increases the vapor pressure in the pressure generator 11 while reducing the vapor pressure in the evaporator 13, which is beneficial to improve the work efficiency of the work device. In this embodiment, the vapor compression device 14 adopts, but is not limited to, mechanical compression (such as a compressor) and a vapor injection compression device.

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

In order to promote the evaporation of the liquid working medium in the evaporator 13, in addition to discharging the vapor working medium by means of compression, an absorption method may also be used. For example, by using the feature of absorbing water vapor in the concentrated lithium bromide solution, the concentrated lithium bromide solution absorbs water vapor, reduces the pressure of the water vapor in the evaporator 13, and promotes the evaporation of the liquid working medium in the evaporator. The dilute lithium bromide solution formed after absorbing water vapor is sent to a steam treatment device, and the water is evaporated by heating the dilute lithium bromide solution to obtain a concentrated lithium bromide solution again, and then the concentrated lithium bromide solution is sent to the evaporator 13 for recycling. According to the selected working medium, use the appropriate absorbing medium to absorb the steam of the working medium, and then after steam treatment, the obtained steam or liquid of the working medium is sent to the pressure generator for circulation.

In addition, in this embodiment, the working medium can be a single working medium, that is, one working medium; two or more working mediums can also be used, and the saturated vapor pressures of various working mediums are different and the vaporization The temperature is different, and multiple working substances can be fully mixed with each other, or one or more working substances can be dissolved in another working substance.

When two working fluids are used, the use of multiple working fluids has the following advantages:

First, when the working medium is heated in the evaporator, the working medium with 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 a higher vapor pressure can be obtained at the same temperature, which is conducive to improving the ability of 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 down the steam working medium and condense it into a liquid working medium.

Second, the working medium with high saturated vapor pressure is easy to vaporize in the evaporator, which is conducive to making the working medium return to the pressure generator, and is conducive to absorbing the heat of the low-temperature heat source.

Third, when one working substance is dissolved in another working substance, the solubility will decrease when the temperature rises, and the dissolved working substance is easy to precipitate in the form of gas, pushing the liquid working substance 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, and as the temperature and pressure drop, the solubility can be restored, and the steam working medium can be quickly dissolved in the liquid working medium , so as to keep the pressure generator working continuously. When the dissolved working medium is heated again, it prepares for the next working cycle.

The choice of working medium can also be a solute working medium that is easily soluble in solvent. When the temperature rises and the pressure rises, the solubility decreases, and it is precipitated from the solvent working medium to form steam. Such as ammonia and water, ammonia is very soluble in water. When the temperature and pressure increase, the solubility of ammonia in water decreases, ammonia is precipitated from water, and ammonia gas is formed on the water surface. The ammonia gas pressure can push the liquid working medium water to do work. After the liquid working medium in the pressure generator flows out, use the heat exchanger in the pressure generator to cool the high-temperature gaseous ammonia in the pressure generator. After the temperature of the ammonia is lowered, the liquid working medium water is introduced, so that the ammonia can be quickly integrated into the liquid In the water, prepare to start the next work cycle.

Therefore, as a modified embodiment of this embodiment, the working medium includes the first working medium and the second working medium, and the first working medium is soluble in the second working medium; the gaseous second working medium The substance is dissolved in the liquid or gaseous vapor absorbing working fluid 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 normal 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 first vaporized, increasing the pressure in the pressure generator 1, thereby pushing the liquid second working medium, or most of the The liquid second work medium and part of the first work medium enter the work device to perform work. The steam of the first and second working fluids in the evaporator is absorbed by the vapor absorption working fluid, thereby reducing the pressure in the evaporator 3 .

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

When the working device 12 is not required to perform work, the liquid working medium flowing out of the working device 12 no longer passes through the evaporator 13 and directly enters the pressure generator 11. At this time, since the working medium does not pass through the evaporator 13, the liquid working medium can only cool down At room temperature, the pressure difference between the working medium inlet and the working medium outlet of the work device 12 is relatively small. Relying on such a cycle, the waste heat in the working system can be used as much as possible until the temperature of the liquid working medium is reduced to the point where it can no longer perform work, thereby converting the waste heat into electrical energy or other energy storage. Or, the liquid working medium flowing out of the power device 12 passes through the evaporator 13, but does not process the working medium vapor in the evaporator, and keeps the vapor pressure constant, so that the liquid working medium that has completed the work passes through the evaporator 13, but the working medium in the evaporator 13 directly into the pressure generator without going through the evaporation process.

Example 2

As shown in Figure 3, the working fluid circulation working system provided by Embodiment 2 includes a pressure generator 11, a working device 12, an evaporator 13, a vapor 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 vapor compression device 14 are connected end-to-end in sequence through pipelines, that is, the working medium outlet of the pressure generator 11 and The working medium inlet of the first heat exchanger 15 is connected, the working medium outlet of the first heat exchanger 15 is connected with the working medium inlet of the work device 12, and the working medium outlet of the work device 12 is connected with the second heat exchanger 16 working medium inlet , the working medium outlet of the second heat exchanger 16 communicates with the working medium inlet of the evaporator 13, the working medium outlet of the evaporator 13 communicates with the working medium inlet of the vapor compression device 14, and the working medium outlet of the vapor compression device 14 communicates with the pressure generator The working medium inlet of 11 is communicated, so that the working medium 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 vapor compression device 14 .

When the temperature of the working medium entering the working device 12 is high, that is, when the temperature of the liquid working medium output by the pressure generator 11 is high, the pressure of the liquid working medium will often be lower than the saturated vapor corresponding to its own temperature as the work progresses. pressure, the liquid working medium will produce steam. If the liquid working medium generates steam in the work device 12, phenomena such as cavitation will occur, which will damage the work device 12 and reduce the service life of the work device 12. The first heat exchanger 15 can reduce the temperature of the liquid working medium entering the power device 12, so that the liquid working medium does not generate steam in the power device 12, and can increase the pressure between the pressure generator 11 and the working medium outlet of the power device 12. The pressure difference makes the work device obtain greater driving force. The first heat exchanger preferably adopts two-stage heat exchange. The first-stage heat exchange is to cool the high-temperature liquid working medium to the ambient temperature; the second-stage heat exchange is to reduce the liquid working medium from the ambient temperature to a lower temperature through cooling. . The cooling capacity of the first heat exchanger 15 preferably comes from the evaporator 13, that is, the low-temperature liquid working medium produced by the evaporator 13 is used to reduce the temperature of the liquid working medium entering the work device 12, so that the liquid that enters the work device 12 can be reduced. At the same time, the temperature of the liquid working fluid entering the pressure generator 11 is increased. That is to say, in this embodiment, the working medium circulation work system is set as follows: firstly, the low-temperature liquid working medium output by the evaporator 13 is transmitted to the first heat exchanger 15 through the pipeline, and then the low-temperature liquid working medium is transmitted to the first heat exchanger 15 through the pipeline. The pressure generator 11, which not only reduces the temperature of the liquid working medium input into the working device 12, reduces the damage of the liquid working medium to the working device 12, but also recycles heat, increases the temperature of the liquid working medium entering the pressure generator 11, and reduces Energy consumption, saving energy.

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, which can be used 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. The low-temperature heat source referred to here 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 .

As a variant embodiment of this embodiment, the working fluid circulation system also includes a steam treatment device, that is, the steam treatment device replaces the steam compression device, and the evaporator 13 is provided with a steam absorption working medium, and the steam absorption working medium absorbs the working medium. Steam, with the reduced pressure of the steam in the evaporator 13, the absorbed working medium and the steam absorption working medium are transported to the steam processing device, so that the working medium and the steam absorption working medium are separated, and the working medium is liquid or steam The mode returns to the pressure generator 11 .

In this variant embodiment, the steam-treated working medium of the steam working medium is not used for working, so it does not participate in working, but is only used to process working working medium. For example, concentrated lithium bromide solution is used as the steam absorption working medium, and water is used as the working medium. Concentrated lithium bromide solution has a strong ability to absorb water vapor. When the water vapor contacts the lithium bromide concentrated solution in the evaporator 13, the water vapor in the evaporator 13 enters the lithium bromide concentrated solution, causing the water vapor pressure in the evaporator 13 to decrease and the water continues to evaporate; the lithium bromide concentrated solution becomes dilute after absorbing the water vapor. The solution then flows out of the evaporator 13. Heating the dilute lithium bromide solution can evaporate the water into water vapor, and obtain the concentrated lithium bromide solution again; the water vapor is sent to the pressure generator 11 again in the form of steam or high-temperature condensed water.

The other structures, connection methods and functions of the working fluid circulation system provided in Embodiment 2 are the same as those in Embodiment 1, and will not be repeated here.

Example 3

As shown in Fig. 4, the working fluid circulation working system provided by Embodiment 3 includes four pressure generators 11a, 11b, 11c, 11d, working device 12, evaporator 13, vapor compression device 14, first heat exchanger 15 and The 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 vapor compression device 14 are connected end-to-end in sequence through pipelines, that is, the pressure The generators 11a, 11b, 11c, and 11d are arranged side by side, and the working medium outlets of the pressure generators 11a, 11b, 11c, 11d communicate with the working medium inlet of the first heat exchanger 15, and the working medium outlet of the first heat exchanger 15 communicates with the working medium inlet of the first heat exchanger 15. The working medium inlet of the work device 12 is connected, the working medium outlet of the work device 12 is connected with the working medium inlet of the second heat exchanger 16, the working medium outlet of the second heat exchanger 16 is connected with the working medium inlet of the evaporator 13, and the evaporator 13 The working medium outlet of the vapor compression device 14 communicates with the working medium inlet of the vapor compression device 14, and the working medium outlet of the vapor compression device 14 communicates with the working medium inlets of the pressure generators 11a, 11b, 11c, 11d. The working medium circulates in the pressure generators 11a, 11b, 11c, 11d, the first heat exchanger 15, the work device 12, the second heat exchanger 16, the evaporator 13 and the vapor compression device 14.

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 receive the steam working medium and liquid working medium output from the evaporator in a circular manner, and circulate Circular work is performed on the work device 12, that is, only one pressure generator performs work on the work device 12 at the same time. In addition, when the pressure generators 11a, 11b, 11c, and 11d receive the liquid working medium output from the evaporator below room temperature, the liquid working medium first absorbs heat from the low-temperature heat source.

Specifically, it is assumed that the initial state of the pressure generators 11a, 11b, 11c, and 11d is: the pressure generator 11a is filled with a relatively high-temperature liquid working medium, and the heating source is used to heat the liquid working medium and increase its internal vapor pressure. The working medium in the devices 11b and 11c is a liquid working medium at normal temperature, and the working medium in the pressure generator 11d is a steam working medium.

When the working system that can utilize a low-temperature heat source starts to operate, the pressure generator 11a performs work on the working device 12, and the vapor compression device 14 compresses the steam working medium in the evaporator 13 and sends it to the pressure generator 11b. The liquid working medium in the pressure generator 11b is heated by the medium. 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 sent to the pressure generator 11c by pressure. Heating the liquid working medium in the pressure generator 11c while keeping the temperature of the liquid working medium in the pressure generator 11b constant; the liquid working medium below room temperature in the evaporator 13 is delivered to the pressure generator 11d by the working medium pump, because At this time, the temperature of the liquid working medium is relatively low, which can absorb the heat in the low-temperature heat source, and make the temperature of the liquid working medium the same as that of the low-temperature heat source. When the liquid working medium in the pressure generator 11a is completely consumed, start the heating source in the pressure generator 11b to make the pressure generator 11b start to work on the working device 12, and send the steam working medium output by the evaporator 13 to pressure The generator 11c uses high-temperature and high-pressure steam working medium to heat the liquid working medium in the pressure generator 11c; at this time, the pressure generator 11d has been filled with the liquid working medium, and the liquid working medium has reached the ambient temperature due to the absorption of heat in 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 vapor pressure output from the evaporator 13 can be sent to the pressure generator 11d while maintaining the temperature of the liquid working medium in the pressure generator 11c , heat the temperature of the liquid working medium in the pressure generator 11c; the low-temperature liquid working medium output from the evaporator 13 is sent to the pressure generator 11a, and the low-temperature liquid working medium in the pressure generator 11a continuously absorbs heat from the environment.

The four pressure generators 11a, 11b, 11c, and 11d circulate in this way repeatedly. The low-temperature liquid working medium output by the evaporator 13 continuously absorbs heat from the low-temperature heat source in the environment and reaches the ambient temperature, and then passes through the high-temperature and high-pressure steam output by the evaporator 13. The working medium is heated, and finally the heating source is used to increase the pressure of the steam working medium to do work, which not only effectively utilizes the low-temperature heat source, reduces energy consumption, but also recycles the heat in the high-temperature and high-pressure steam working medium output by the evaporator 13, saving energy. energy.

As a modified embodiment of this embodiment, the working system that can utilize low-temperature heat source includes four pressure generators 11a, 11b, 11c, 11d, two working devices 12, one evaporator 13, one vapor compression device 14, two The work devices 12 are arranged side by side, and the four pressure generators 11a, 11b, 11c, 11d perform work on the two work devices 12 in cycles, and the two work devices 12 output the work medium to the evaporator 13, or one work device outputs the work medium output to the evaporator 13, and another 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 vapor compression as much as possible and reduce the burden on the heat storage device. The rest of the steps and the circulation of the working fluid are the same as those in other embodiments, and will not be repeated here.

Example 4

As shown in Figure 5, the work system provided by Example 4 that can utilize low-temperature heat sources includes two working medium circulation work systems. system and the next-level working fluid circulation system, correspondingly, the pressure generator, power device, evaporator and vapor compression device set in the upper-level working fluid circulation system are called the upper-level pressure generator 11a, The upper stage work device 12a, the upper stage evaporator 13a and the upper stage vapor compression device 14a; the pressure generator, work device, evaporator and vapor compression device set in the next stage working fluid circulation work system The next-stage pressure generator 11b, the next-stage working device 12b, the next-stage evaporator 13b and the next-stage vapor compression device 14b.

The specific structure of the working system that can utilize the low-temperature heat source provided by embodiment 4 is as follows:

In the upper-stage working fluid circulation work system, the upper-stage pressure generator 11a, the upper-stage work device 12a, the upper-stage evaporator 13a, and the upper-stage vapor compression device 14a are connected end-to-end in sequence through pipelines; In the secondary working fluid circulation work system, the next-stage pressure generator 11b, the next-stage work device 12b, the next-stage evaporator 13b and the next-stage vapor compression device 14b are connected end-to-end in sequence through pipelines. The specific connection mode and functions of the upper-level working fluid circulation system and the lower-level working fluid circulation system are the same as those in Embodiment 2, and will not be repeated here. Moreover, the liquid working medium outlet of the upper stage evaporator 13a and the working medium outlet of the next stage vapor 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 next stage vapor compression device 14b The temperature of the upper low-temperature liquid working medium is heated, and the lower steam working medium is condensed at the same time.

It should be pointed out that although the working system that can utilize low-temperature heat source provided in Embodiment 4 is provided with two working fluid circulation working systems, the present invention is not limited thereto. 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 work system that can utilize low-temperature heat sources includes an n-stage working medium circulation work system, and the n-stage work medium circulation work systems are connected step by step, that is, the upper-stage evaporator 13a and the lower-stage vapor compression device 14b are arranged in a heat exchange manner , wherein, n is a positive integer greater than or equal to 2, so that the heat in the working medium is recycled. The working fluid circulation system can use heat and cold to heat up and cool down accordingly.

Example 5

As shown in FIG. 6 , the working system provided by Embodiment 5 that can utilize a low-temperature heat source includes a working fluid circulation working system and a steam working device.

The structure of the working fluid circulation work system is the same as that of the working medium circulation work system in Embodiment 1, which includes a pressure generator 11, a work device 12 and an evaporator 13, and the pressure generator 11, the work device 12 and the evaporator 13 The pipelines are connected end to end in sequence.

The steam work device adopts the steam work device currently available on the market, which includes a steam work system pressure generator 61, a steam work system work device 62 and a steam work system working fluid pump 63, a steam work system pressure generator 61, and a steam work system. The device 62 and the working medium pump 63 of the steam working system are connected end-to-end in turn through pipelines, the working medium outlet of the steam working device pressure generator 61 is connected with the working medium inlet of the steam working system working device 62, and the working medium of the steam working system working device 62 The outlet is connected with the input port of the working medium pump 63, and the output port of the working medium pump 63 of the steam working system is connected with the working medium inlet of the pressure generator 61 of the steam working system. The working medium pump 63 of the working medium pump 63 of the working device 62 and the steam working system circulates inside, and the working medium pump 63 of the steam working system provides the power for circulating the working medium.

The working medium inlet of the pressure generator 11 and the working medium outlet of the working medium of the steam working system 62 are arranged in a heat exchange manner, that is, the high-temperature steam working medium discharged from the working medium of the steam working system 62 and the low-temperature liquid at the working medium inlet of the pressure generator 11 The working medium performs heat exchange. On the one hand, the low-temperature liquid working medium at the working medium inlet of the pressure generator 11 is heated, which is beneficial to generate high pressure in the pressure generator 11; The substance is cooled, condensed into liquid, and then transported to the pressure generator 61 of the steam work system by the working pump 63, and the heat released by the condensation is utilized, saving energy.

Example 6

As shown in FIG. 7 , the work system provided by Embodiment 6 that can utilize a low-temperature heat source includes a working fluid circulation work system and a steam work device.

Specifically, the work system that can utilize a low-temperature heat source includes a pressure generator 11, a work device 12, an evaporator 13, a steam work system pressure generator 61, and a steam work system work device 62, and the steam work system pressure generator 61, steam The 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 medium outlet of the steam working system pressure generator 61 communicates with the working medium inlet of the steam working system working device 62 , the working medium outlet of the steam work system working device 62 is connected with the working medium inlet of the pressure generator 11, the working medium outlet of the pressure generator 11 is connected with the working medium inlet of the working device 12, and the working medium outlet of the working device 12 is connected with the evaporator 13 is connected to the working medium inlet, and the working medium outlet of the evaporator 13 is connected to the working medium inlet of the pressure generator 61 of the steam power system. 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 .

The high-temperature liquid working medium discharged between the pressure generator 11 and the work device 62 is returned to the pressure generator 61 of the steam work system to effectively utilize the heat of the high-temperature liquid work medium and reduce the energy consumption of the steam work system.

Example 7

As shown in FIG. 8 , the work system provided by Embodiment 7 that can utilize a low-temperature heat source includes a working fluid circulation work system and a steam work device.

The structure of the working fluid circulation system is the same as that of the working medium circulation system in Embodiment 2, which includes a pressure generator 11, a work device 12, an evaporator 13 and a vapor compression device 14, and the pressure generator 11, the work device 12. The evaporator 13 and the vapor compression device 14 are connected end-to-end in sequence through pipelines.

The steam work device adopts the steam work device currently available on the market, which includes a steam work system pressure generator 61, a steam work system work device 62 and a steam work system working fluid pump 63, a steam work system pressure generator 61, and a steam work system. The device 62 and the working medium pump 63 of the steam working system are connected end-to-end in turn through pipelines, the working medium outlet of the steam working device pressure generator 61 is connected with the working medium inlet of the steam working system working device 62, and the working medium of the steam working system working device 62 The outlet is connected with the input port of the working medium pump 63, and the output port of the steam working system working medium pump 63 is connected with the working medium inlet of the steam working system pressure generator 61, so that the working medium is in the steam working system pressure generator 61, steam The working device 62 of the working system and the working medium pump 63 of the steam working system circulate and flow, and the working medium pump 63 of the steam working system provides the power for circulating the working medium.

The working medium outlet of the evaporator 13 and the work device 62 of the steam work system is set in a heat exchange manner, so as to use the low-temperature liquid working medium output by the evaporator 13 to cool the steam work medium discharged from the work device 62 of the steam work system, and at the same time heat the output of the evaporator 13 The cryogenic liquid working medium temperature. In addition, the vapor compression device 14 and the steam power system pressure generator 61 are arranged in a heat exchange manner, and the high temperature and high pressure steam working medium output by the vapor compression device 14 is used to increase the temperature of the working medium in the steam power system pressure generator 61 .

In this embodiment, the evaporator 13 utilizes the waste heat output by the steam power device to reduce the temperature of the working medium entering the steam power system working medium pump 63 and reduce the damage to the steam power system working medium pump 63 . At the same time, the pressure generator 61 of the steam work system 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 work efficiency of the steam work device.

Example 8

As shown in FIG. 9 , the work system provided by Embodiment 8 that can utilize a low-temperature heat source includes a working fluid circulation work system and a refrigeration system.

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 refrigeration system evaporator The working medium output port of 71 is connected with the working medium inlet of the refrigeration system compressor 73, the working medium outlet of the refrigeration system compressor 73 is connected with the working medium inlet of the refrigeration system condenser 72, and the working medium outlet of the refrigeration system condenser 72 is connected with the refrigeration system condenser 72. The working medium input port of the system evaporator 71 is connected. The refrigeration system evaporator 71 absorbs heat to evaporate the refrigerant, the refrigeration system compressor 73 pressurizes the refrigerant to the refrigeration system condenser 72, and the refrigeration system condenser 72 dissipates heat to cool the refrigerant.

The structure of the working fluid circulation system is the same as that of the working medium circulation system in Embodiment 2, which includes a pressure generator 11, a work device 12, an evaporator 13 and a vapor compression device 14, and the pressure generator 11, the work device 12. The evaporator 13 and the vapor compression device 14 are connected end-to-end in sequence through pipelines.

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 beneficial Reduce heat loss. Moreover, the refrigeration system condenser 72 and the pressure generator 11 are arranged in a heat exchange manner. The condenser 72 of the refrigeration system in the refrigerant will release a large amount of heat during the condensation process, and the heat can be utilized by the pressure generator 11 to increase the temperature of the liquid working medium in the pressure generator 11 .

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

Since the latent heat of vaporization of the working medium is very high, in addition to part of the steam condensing to transfer heat to the liquid working medium, the condensing working medium must first absorb the latent heat of vaporization of the high-temperature and high-pressure working medium, so that the working medium steam is completely liquefied. These higher-temperature condensed working fluids are stored in the energy storage device first, and when the work requirements are low, they return directly to the pressure generator without passing through the evaporator; The vapor pressure of the working medium in the evaporator, so that the liquid working medium will no longer evaporate and all flow into the pressure generator. This method can consume the heat of the condensed working medium of the energy storage device, but the working power will be reduced. In Embodiment 4, the purpose of setting the work device in parallel is also to reduce the heat of this part and reduce the burden of the energy storage device.

In the working system provided by the above embodiments that can utilize a low-temperature heat source, when the working medium evaporates in the evaporator, a low-temperature liquid working medium and a high-temperature steam working medium below room temperature can be generated. The low-temperature liquid working medium can be placed in the pressure generator or Before entering the pressure generator, absorb the heat in the low-temperature heat source to make its temperature reach the temperature of the low-temperature heat source, which can reduce the energy consumed when the pressure generator vaporizes the liquid working medium, and in the pressure generator, the low-temperature liquid working medium can be used The heat in the high-temperature steam working medium output by the evaporator is used to increase its temperature or vaporize the liquid working medium, thereby recycling the heat. Therefore, the working system not only utilizes low-temperature heat sources in the environment such as air, rivers, lakes, and seas to expand the range of energy sources, but also recycles the heat in the steam working medium generated by the evaporator to save energy.

Example 9

As shown in Figure 10, this embodiment provides a method that can use a low-temperature heat source to perform work. The method is based on the work system provided in Embodiment 1 to Embodiment 8. The method includes the following steps:

Step S1, heating the liquid working medium in the pressure generator to vaporize it and increasing the pressure of the steam in the pressure generator, so as to pressurize the liquid working medium to the work device;

Step S2, the liquid working medium is sent to the evaporator after completing the work in the work device;

In step S3, the liquid working medium is vaporized in the evaporator to obtain a steam working medium, and at the same time, the steam working medium is absorbed by the vapor absorbing working medium in the evaporator, and discharged out of the evaporator.

Step S4, separating the steam working medium from the steam absorbing working medium, returning the separated steam working medium to the pressure generator, and returning the steam absorbing working medium to the evaporator at the same time.

Although the present invention has been described in detail with general descriptions and specific examples above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (10)

1. A work system that can utilize a low-temperature heat source, is characterized in that, the described work system that can utilize a low-temperature heat source includes a working medium circulation work system, and the work medium circulation work system includes a pressure generator, a work device and an evaporator, The pressure generator, the working device and the evaporator are sequentially connected end to end for the circulating flow of the working medium; the evaporator obtains the steam working medium and the liquid working medium below room temperature during the process of vaporizing the working medium, and the low The liquid working medium at 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 elevate the pressure generator. steam pressure to push the liquid working medium to do work in the work device. 2. The working system that can utilize a low-temperature heat source according to claim 1, wherein the working medium circulation working system also includes a vapor compression device, and the vapor compression device is connected in series between the evaporator and the pressure Between the generators, the vapor compression device sucks and compresses the vapor working medium generated by the evaporator to reduce the pressure of the vapor in the evaporator, and then sends the compressed vapor working substance to the pressure generator; Alternatively, the working medium circulation system also includes a steam treatment device, and the vapor absorbing working medium is arranged in the evaporator, and the steam absorbing working medium absorbs the steam of the working medium to reduce the steam in the evaporator. steam pressure, the absorbed working medium and the steam absorption working medium are transported to the steam processing device, so that the working medium is separated from the steam absorption working medium, and the working medium is Liquid or steam is returned to the pressure generator. 3. The work system that can utilize a low-temperature heat source according to claim 2, wherein the work system that can utilize a low-temperature heat source includes n-level described working medium circulation work systems that are connected step by step, and the upper level The evaporator and the vapor compression device at 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 that can utilize a low-temperature heat source according to claim 2, wherein the work system that can utilize a low-temperature heat source also includes a steam work system, and the steam work system includes a steam work system pressure generator, a steam work system, and a steam work system. The working device of the working system and the working medium pump of the steam working system, the pressure generator of the steam working system, the working device of the steam working system and the working medium pump of the steam working system are connected in sequence from end to end; In addition, the pressure generator of the steam work system and the steam compression device of the working medium circulation work system are arranged in a heat exchange manner, and the work device of the steam work system is heat exchanged with the evaporator of the work medium circulation work system mode setting; Alternatively, the working device of the steam working system and the pressure generator of the working fluid circulation working system are arranged in a heat exchange manner. 5. The work system that can utilize a low-temperature heat source according to claim 2, wherein the work system that can utilize a low-temperature heat source also includes a steam work system, and the steam work system includes a steam work system pressure generator and a steam work system. The working device of the working system, the pressure generator of the steam working system, the working device of the steam working system, the pressure generator, the working device and the evaporator are connected end to end in sequence, and the working medium outlet of the pressure generator It communicates with the working medium inlet of the steam power system pressure generator, and the working medium outlet of the evaporator communicates with the working medium inlet of the pressure generator. 6. The working system that can utilize low-temperature heat source according to any one of claims 1-5, characterized in that, the working system that can utilize low-temperature heat source includes a plurality of said pressure generators and a plurality of working units arranged in parallel device, the multiple pressure generators sequentially receive the liquid working medium and the steam working medium output by the evaporator in a cycle, and the multiple working devices are arranged in parallel to perform work in a cycle. 7. The working system that can utilize a low-temperature heat source according to any one of claims 1-5, wherein a heating source is arranged in the pressure generator to increase the steam pressure in the pressure generator . 8. The working system that can utilize a low-temperature heat source according to any one of claims 1-5, wherein the working medium includes a first working medium and a second working medium, and the first working medium The working medium and the second working medium can be fully mixed, or the first working medium can be dissolved in the second working medium; in the evaporator, the gaseous working medium is converted into gaseous or liquid The vapor existing in the absorption mode is absorbed by the working medium and discharged from the evaporator to reduce the vapor pressure of the working medium in the evaporator. 9. The work system that can utilize a low-temperature heat source according to any one of claims 1-5, wherein the working medium circulation work system also includes a first heat exchanger and/or a second heat exchanger, so The working medium inlet of the first heat exchanger communicates with the working medium outlet of the pressure generator, the working medium outlet of the first heat exchanger communicates with the working medium inlet of the work device, and the first heat exchange The device is used to reduce the temperature of the working fluid entering the working device; the working fluid inlet of the second heat exchanger communicates with the working fluid outlet of the working device, and the working fluid outlet of the second heat exchanger In communication with the working medium inlet of the evaporator, the second heat exchanger is used to increase the temperature of the working medium entering the evaporator. 10. A method that can utilize a low-temperature heat source to perform work, characterized in that, the method is based on the work system described in any one of claims 1-9, and the method comprises the following steps: Step S1, heating the liquid working medium in the pressure generator to vaporize it and increasing the pressure of the steam in the pressure generator, so as to pressurize the liquid working medium to the work device. Step S2, the liquid working medium is sent to the evaporator by pressure after completing work in the work device. In step S3, the liquid working medium is vaporized in the evaporator to obtain a steam working medium, and at the same time, the steam working medium is absorbed by the vapor absorbing working medium in the evaporator and discharged from the evaporator. Step S4, separating the steam working medium from the steam absorbing working medium, returning the separated steam working medium to the pressure generator, and returning the steam absorbing working medium to the evaporator at the same time .