CN117780601A - Efficient reciprocating piston type device and heat pump energy storage system adopting same - Google Patents

Abstract

The application belongs to the technical field of compressors, and particularly relates to a high-efficiency reciprocating piston type device and a heat pump energy storage system adopting the same, wherein the high-efficiency reciprocating piston type device comprises an exhaust valve, an air inlet valve, a piston assembly, a transmission mechanism, a guide rail and a cylinder body; the piston assembly and the transmission mechanism are positioned in the cylinder body, and the bottom of the piston assembly is connected with the transmission mechanism; the guide rail is provided with a bearing, the piston assembly is contacted with the bearing of the guide rail, and the guide rail is connected with the inner wall of the cylinder body; the exhaust valve and/or the air inlet valve are/is an opening and closing active control valve, and the exhaust valve and the air inlet valve are communicated with the working cavity; the piston assembly and the inner wall of the cylinder body are sealed by a gap and/or completely sealed; at least one end of the piston assembly is a working chamber. The side force and friction between the piston and the cylinder body are reduced through the guide rail, and meanwhile, the friction between the piston and the guide rail is reduced through the rolling bearing, so that lower friction loss can be achieved under higher running frequency, and the device has the characteristic of high efficiency.

Description

Efficient reciprocating piston type device and heat pump energy storage system adopting same

Technical Field

The invention belongs to the technical field of compressors, and particularly relates to a high-efficiency reciprocating piston type device and a heat pump energy storage system adopting the device.

Background

The heat pump energy storage principle is that off-peak electric energy or surplus electric energy is converted into high-temperature heat energy and low-temperature cold energy through reverse circulation and is stored respectively, when electricity is used, the stored high-temperature heat energy is used as a high-temperature heat source, the low-temperature cold energy is used as a low-temperature cold source through forward power circulation, and heat/cold energy is converted into electric energy to be released. Therefore, the heat pump energy storage technology has the advantages of lower cost, no limitation of geographical positions and higher energy storage density, and is a novel large-scale electric energy storage technology with great prospect at present.

At present, the main technical scheme of heat pump energy storage adopts a compressor and an expander of a turbine machine, but the technical scheme of the turbine machine needs two sets of equipment, one set of equipment is used for energy storage and the other set of equipment is used for power generation, so that the cost is too high, and the efficiency of the turbine machine can only reach about 90% at present, so that the efficiency of an energy storage system is lower. Therefore, searching for other forms of efficient compressor and expander solutions is very important for heat pump energy storage. The reciprocating piston compressor and the expander can realize energy storage and power generation by adopting one set of equipment, so that the reciprocating piston compressor and the expander have advantages in equipment cost, but the efficiency of the reciprocating piston compressor and the expander facing refrigeration application at present is very poor and is far lower than the isentropic efficiency of 90% of a large-scale turbine machine, so that the heat pump energy storage scheme based on the reciprocating piston device is greatly lower in energy storage efficiency than the scheme based on the turbine machine, the cost advantage on the equipment is reduced, and the energy storage efficiency is too low to cause lack of market competitiveness and economy. Therefore, improving the efficiency of the reciprocating piston compressor and the expander is of great importance for heat pump energy storage schemes based on reciprocating piston devices, and also has great economic value.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the high-efficiency reciprocating piston type device and the heat pump energy storage system adopting the device, at least one of the air inlet valve and the air outlet valve of the high-efficiency reciprocating piston type device is an active control valve for opening and closing, the guide rail of the high-efficiency reciprocating piston type device is provided with the bearing, the lateral force and friction between the piston and the cylinder body are reduced through the guide rail, and meanwhile, the friction between the piston and the guide rail is reduced through the bearing, so that the high-efficiency reciprocating piston type device has the characteristics of lower friction loss at higher operating frequency and high efficiency.

In order to achieve the technical purpose of the invention, the invention adopts the following technical scheme:

a high-efficiency reciprocating piston device comprises an exhaust valve, an air inlet valve, a piston assembly, a transmission mechanism and a cylinder body; the device is characterized by also comprising a guide rail;

the piston assembly and the transmission mechanism are positioned in the cylinder body, and the bottom of the piston assembly is connected with the transmission mechanism; the guide rail is provided with a bearing, the piston assembly is contacted with the bearing of the guide rail, and the guide rail is connected with the inner wall of the cylinder body;

the exhaust valve and/or the air inlet valve are/is an opening and closing active control valve, and the exhaust valve and the air inlet valve are communicated with the working cavity;

and a clearance seal and/or a complete seal is adopted between the piston assembly and the inner wall of the cylinder body.

Further, the clearance between the outer wall of the piston and the inner wall of the cylinder body of the piston assembly is 1 μm-100 μm.

Further, the device also comprises a first motor, wherein the first motor is connected with a transmission mechanism, and at least one friction pair of the transmission mechanism adopts a rolling bearing;

and/or the bearings of the guide rail adopt rolling bearings.

Further, in the opening process of the air inlet valve, the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston is between 10 and 50 percent;

and/or, in the opening process of the exhaust valve, the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston is between 10 and 50 percent.

Further, the ratio of the exhaust pressure to the intake pressure in the working chamber is 1.5-5.

Further, the hydraulic oil pump further comprises an elastic element, the elastic element and the piston assembly are matched to form a liquid cavity, one surface of the elastic element is contacted with working medium gas in the working cavity, and the other surface of the elastic element is contacted with liquid in the liquid cavity;

the elastic element is a corrugated pipe or a diaphragm.

Further, the elastic element is provided with at least two structures, namely a first elastic element and a second elastic element, and the first elastic element or the second elastic element is matched with the piston assembly.

Further, the upper end and the lower end of the first elastic element are communicated, one end of the first elastic element is in sealing connection with the piston assembly, the other end of the first elastic element is in sealing connection with the cylinder body side, the inner side surface of the first elastic element is in contact with working medium gas in the working cavity, and the outer side surface of the first elastic element is in liquid contact with the liquid in the liquid cavity;

the second elastic element is sleeved on the rod part of the piston assembly and is positioned above the sliding block with the central hole, the piston assembly is fixedly arranged in the central hole of the sliding block in a penetrating manner, the sliding block is arranged in the sliding rail with the central hole in a penetrating manner and is in sliding connection with the sliding rail, one end of the second elastic element is connected with the piston assembly, the other end of the second elastic element is connected with the sliding rail, one surface of the second elastic element is in liquid contact with the liquid in the liquid cavity, and the other surface of the second elastic element is in gas contact with working medium in the working cavity.

Further, one end of a rod part of the piston assembly is connected with the piston, the other end of the rod part is connected with the transmission mechanism, a bearing of the guide rail is sleeved on the connecting rod, and the rod part is provided with a flange plate which is horizontally arranged;

the cylinder body inner wall has annular current limiting cylinder, the ring flange is located annular current limiting cylinder inboard, have the clearance between ring flange outer wall and the inner wall of annular current limiting cylinder.

The invention also provides a heat pump energy storage system adopting the efficient reciprocating piston type device, which comprises a high-temperature heat exchanger, an expander, a low-temperature heat exchanger, a compressor, a second motor and a heat regenerator;

At least one of the expander and the compressor employing a high efficiency reciprocating piston device as defined in claims 1-9; the inlet temperature of the compressor under the rated working condition is more than or equal to 100 ℃ and/or the ratio of the exhaust pressure to the inlet pressure of the compressor is 1.5-5.

According to the technical scheme, compared with the prior art, the invention has the following advantages:

compared with the traditional reciprocating piston device, the air inlet and outlet valve is passive, namely, the opening and the closing of the air inlet and outlet valve are realized under the action of pressure difference at two ends of the valve, so that larger pressure drop is generated in the air inlet process and the air outlet process, and larger irreversible loss is generated; the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston in the opening process of the air inlet valve and the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston in the opening process of the air outlet valve are preset, so that smaller air inlet and outlet losses can be realized; in a conventional reciprocating piston device, the piston and the wall surface are usually sealed by a piston ring, and the piston ring is tightly attached to the wall surface of a cylinder due to the action of sealing medium force, so that larger friction loss is generated between the piston ring and the wall surface of the cylinder, and in the reciprocating piston device such as an internal combustion engine, the friction loss between the piston ring and the wall surface of the cylinder accounts for 50% -70% of all friction loss, therefore, the efficient reciprocating piston device adopts a gap The sealing or complete sealing is realized without adopting a sealing ring, which is very important for reducing friction loss and realizing high efficiency of the reciprocating piston device, and leakage loss caused by eliminating a piston ring in gap sealing can be reduced through higher operation frequency; due to the use of the guide rail, a reciprocating linear movement of the piston is achieved and a gap is present>Compared with the traditional structure, the piston ring on the piston and the wall surface of the cylinder body move in a friction way, so that the lateral force generated by the transmission mechanism is transferred between the piston and the guide rail from the traditional application between the piston and the wall surface of the cylinder body, and compared with the traditional structure, the friction loss is reduced due to lower friction coefficient of the bearing under the same lateral force;

secondly, in a preferred implementation mode, the inverted V-shaped structure of the crank can convert the axial rotary motion of the crank into the reciprocating linear motion of the second connecting rod, so as to drive the piston assembly to reciprocate in the cylinder body;

third, in a preferred implementation, the present invention is to reduce the sealing gap between the outer wall of the piston and the inner wall of the cylinderAt least 1 ring groove is arranged on the circumferential ring of the outer wall of the piston, so that a sealing medium forms vortex in the ring groove to generate resistance, and leakage is reduced;

Fourth, in a preferred implementation, the bearings in the guide rail of the present invention are rolling bearings, which have a much smaller coefficient of friction than sliding bearings;

fifth, in the preferred implementation manner, when the fit clearance between the piston and the cylinder is between 1 μm and 100 μm, if the fit clearance is smaller, the problem of larger friction loss caused by friction between the piston and the cylinder in the operation process may exist due to the influence of frequency, processing, assembly and the like between the piston and the cylinder, and if the fit clearance is larger, the loss of working medium leakage between the piston and the cylinder is larger, therefore, the piston of the efficient reciprocating piston type device is completely sealed by adopting an elastic element, the loss of working medium leakage at the fit position of the piston can be eliminated, the friction between the piston and the cylinder at the fit clearance between the piston and the cylinder can be completely eliminated, even if the elastic element, the cylinder and the piston form a liquid cavity, oil filling is performed in the liquid cavity, and the fit clearance for sealing oil exists between the piston and the cylinder after the elastic element is adopted, on the one hand, good lubrication is generated, on the other hand, the loss of the leakage of the working medium is much smaller under the same pressure difference, the loss of working medium is mainly the loss of work, the efficiency loss caused by the leakage quality is much smaller than the leakage, and the friction loss caused by the sealing medium leakage is also much smaller than the loss under the leakage quality, and the working medium leakage quality can not enter the working medium, but the friction loss is also reduced on the whole friction mechanism is small due to the fact that the friction loss is not enters the working medium and has a friction mechanism;

Sixth, the invention provides a heat pump energy storage system adopting a high-efficiency reciprocating piston device, at least one of an expander and a compressor in the heat pump energy storage system adopts the high-efficiency reciprocating piston device, the other one can adopt the high-efficiency reciprocating piston device, and also can adopt a turbine type device, at least one of an air inlet valve and an air outlet valve of the high-efficiency reciprocating piston device is used for opening and closing an active control valve, a guide rail of the high-efficiency reciprocating piston device is provided with a bearing, lateral force and friction between a piston and a cylinder body are reduced through the guide rail, meanwhile, friction between the piston and the guide rail is reduced through the bearing, and the heat pump energy storage system has the characteristics of lower friction loss and high efficiency under higher operation frequency.

Drawings

FIG. 1 is a schematic structural view of a high efficiency reciprocating piston device of embodiment 1 of the present invention;

FIG. 2 is a schematic structural view of another implementation of the high efficiency reciprocating piston device of embodiment 1 of the present invention;

fig. 3 is a schematic view showing the structure of an intake valve for realizing opening and closing in embodiment 1 of the present invention;

FIG. 4 is a schematic diagram showing the connection structure of the piston assembly and the transmission mechanism of embodiment 2 of the present invention;

FIG. 5 is a schematic diagram of the structure of a crank of the transmission mechanism of embodiment 2 of the present invention;

FIG. 6 is a schematic view showing the structure of a guide rail of the high-efficiency reciprocating piston type apparatus of embodiment 3 of the present invention;

FIG. 7 is a schematic view of a high efficiency reciprocating piston device with a first elastic member according to embodiment 4 of the present invention;

fig. 8 is a schematic structural view of a first elastic member of embodiment 4 of the present invention;

FIG. 9 is a schematic diagram II of a high efficiency reciprocating piston device with a first elastic element according to embodiment 4 of the present invention;

FIG. 10 is a schematic view of a high efficiency reciprocating piston device with a second elastic element according to embodiment 4 of the present invention;

FIG. 11 is a schematic diagram II of a high efficiency reciprocating piston device with a second elastic element of embodiment 4 of the present invention;

FIG. 12 is a schematic diagram of a heat pump energy storage system employing a high efficiency reciprocating piston device in accordance with example 5 of the present invention;

fig. 13 is a schematic diagram of a heat pump energy storage system employing a high efficiency reciprocating piston device according to embodiment 6 of the present invention.

Wherein, 1-exhaust valve; 2-an intake valve; 3-piston assembly; 30-a piston; 300-ring groove; 31-a first link; 4-a guide rail; 5-a first motor; 6-a transmission mechanism; 60-a second link; 61-crank; 7-an annular flow-limiting cylinder; 8 a-a first elastic element; 8 b-a second elastic element; 9-a slider; 10-sliding rails; a, lubricating liquid; b1-a high-temperature heat exchanger; b2-expander; b3-a low-temperature heat exchanger; b4-compressor; b5-a heat regenerator; c1-a cylinder body; c2-sealing plate; and C3-telescopic motor.

Detailed Description

In order to better understand the technical solutions of the present application, the following further details of the novel present invention will be described with reference to the accompanying drawings and examples.

The terms of upper, lower, left, right, front, rear, and the like in the present application are established based on the positional relationship shown in the drawings. The drawings are different, and the corresponding positional relationship may be changed, so that the scope of protection cannot be understood.

In the present application, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, integrally connected, mechanically connected, electrically connected or communicable with each other, directly connected, indirectly connected through an intermediate medium, communicated between two components, or an interaction relationship between two components. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

At present, 90% of efficiency can be realized by a main stream turbine compressor and a turbine expander, the technology is very mature, but the space for continuously improving the efficiency is very small, and as multiple energy conversion occurs in the heat pump energy storage process, the 90% of compression and expansion efficiency leads to lower energy storage efficiency of a heat pump energy storage system based on turbine machinery, and related researches show that the energy storage efficiency can only reach about 50%. The efficiency of the current reciprocating piston device is far lower than 90%, so that the current reciprocating piston device does not have the potential of being applied to a heat pump energy storage system, various losses of the current reciprocating piston device need to be improved, and the efficiency of the current reciprocating piston device is improved, so that the current reciprocating piston device has application value.

Losses of the reciprocating piston device include intake and exhaust throttling losses, gas and wall heat exchange losses, leakage losses and friction losses. The inventors of the present application found that: in the traditional reciprocating piston device, the air inlet and outlet valves are passive, namely, the opening and closing of the air inlet and outlet valves are realized under the action of pressure difference at two ends of the valves, so that larger irreversible loss is generated in the air inlet process and the air outlet process, therefore, for the reciprocating piston device using heat pump energy storage as application, the air inlet and outlet valves are required to be adopted for realizing high efficiency, further, in order to realize smaller air inlet and outlet loss, the ratio of the maximum flow area of a working medium to the area corresponding to the diameter of a piston in the opening process of the air inlet valve is between 10% and 50%, and the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston in the opening process of the air inlet valve is preferably between 25% and 35%; in the process of opening the exhaust valve, the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston is between 10 and 50 percent, and preferably, the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston in the process of opening the exhaust valve is between 15 and 35 percent.

Further, the inventors of the present application found that: in a heat pump energy storage system, the compressor pressure ratio is higher, and the pressure ratio is generally required to be more than 10, because the higher the pressure ratio is, the higher the ratio of the temperature in the high-temperature heat exchanger to the temperature in the low-temperature heat exchanger is, the higher the system efficiency is under the condition of lower expander efficiency, for the turbo mechanical compressor and the expander, the heat exchange loss generated by the high pressure ratio is smaller because working medium flows unidirectionally, however, for a reciprocating piston type device, the low-temperature working medium flows into the compressor to exchange heat with the wall surface, the high-temperature working medium exchanges heat with the same wall surface in the compression process, so when the pressure ratio is higher, the heat exchange loss of the high-temperature working medium at the moment of compression end is higher, if lower operation frequency, such as 1Hz frequency is adopted, and according to the calculation of an inventor, the efficiency loss of approximately 10% is generated only by the heat exchange loss, therefore, the efficient reciprocating piston type device has to reduce the heat exchange loss, further, the operation frequency is improved and the heat exchange loss can be reduced by reducing the heat exchange loss by the high-efficiency reciprocating piston type device by adopting higher operation frequency.

The inventors of the present application found that: the use of a high operating frequency results in an increase in friction loss, resulting in a friction loss of 3% to 8%, and therefore, although the heat exchange loss is reduced, the friction loss is increased, resulting in that the efficiency of the reciprocating piston type apparatus is still difficult to exceed 90%. Further, the inventors of the present application found that: for heat exchange loss and friction loss in the reciprocating piston type device, the heat exchange loss is difficult to reduce by other technologies except for reducing the pressure ratio, and the friction loss has potential for reducing due to linear motion friction mainly generated between a piston and a cylinder and rotation motion friction inside a transmission mechanism, so that the reduction of the heat exchange loss by adopting a method for reducing the friction loss is very critical for realizing the high efficiency of the reciprocating piston type device.

The inventors of the present application found that: in the heat pump energy storage system, because the pressure is higher and the expansion work is recovered, lubricating oil cannot be contained, friction pairs between a piston and a cylinder wall surface and inside a transmission mechanism are usually dry friction, so that friction loss is large, therefore, the piston linear motion guide rail device is adopted to realize reciprocating linear motion of the piston, so that side force generated by the transmission mechanism is transferred between the piston and the piston linear motion guide rail device from the position, which is applied between the piston and the cylinder wall surface, of the transmission mechanism, the piston linear motion guide rail device is provided with a bearing, so that friction loss is reduced due to the fact that the friction coefficient of the bearing is lower under the same side force, compared with a sliding bearing, the friction coefficient of the rolling bearing is much smaller, and the reduction of any loss is critical to a reciprocating piston type device applied to the heat pump energy storage system, because the reciprocating piston type device needs to compete with a turbine compressor with 90% efficiency, meanwhile, the heat pump energy storage system needs to compete with other energy storage modes such as pumping energy storage and battery energy storage, and the like, therefore, preferably, the bearing in the piston linear motion guide rail device is a rolling bearing, and the friction pair inside the transmission mechanism also adopts the rolling bearing.

Further, the inventors of the present application found that: the piston ring is usually used for sealing between the piston and the wall surface of the reciprocating piston device, and the piston ring is tightly attached to the wall surface of the cylinder due to the action of sealing medium force, so that larger friction loss is generated between the piston ring and the wall surface of the cylinder, and in the reciprocating piston device such as an internal combustion engine, the friction loss between the piston ring and the wall surface of the cylinder accounts for 50% -70% of all friction loss.

The inventors of the present application found that: the service life and friction coefficient of the bearing are affected by temperature and lubrication, and the heat pump energy storage system is usually an oil-free system, so that an elastic element is adopted to isolate working medium of the working cavity, and therefore the linear motion guide rail device of the piston and the transmission mechanism can be lubricated and cooled by liquid, and further friction loss is reduced. Further, the inventors of the present application found that: when the fit clearance between the piston and the cylinder is between 1 mu m and 100 mu m, the problem that the friction loss is large due to the influence of frequency, processing, assembly and the like between the piston and the cylinder possibly exists in the operation process, and when the fit clearance is large, the leakage loss of working medium between the piston and the cylinder is large, so that the piston of the efficient reciprocating piston device is completely sealed by adopting the elastic element, the leakage loss of working medium at the matched position of the piston can be eliminated, the friction between the piston and the cylinder at the fit clearance caused by the fit clearance between the piston and the cylinder can be completely eliminated, even if the elastic element, the cylinder and the piston form a liquid cavity, the liquid cavity is filled with oil, the fit clearance between the piston and the cylinder is filled with sealing oil after the elastic element is adopted, on the one hand, good lubrication can be generated, on the other hand, the viscosity coefficient of the lubricating oil is high, the leakage loss is much smaller under the same pressure difference, and the efficiency loss caused by the leakage quality is much smaller than the working medium leakage.

Example 1:

referring to fig. 1 of the drawings, a high-efficiency reciprocating piston device comprises an exhaust valve 1, an intake valve 2, a piston assembly 3, a guide rail 4, a first motor 5, a transmission mechanism 6 and a cylinder body. The piston assembly 3 includes a piston 30 and a first link 31.

The piston assembly 3, the guide rail 4, the first motor 5 and the transmission mechanism 6 are positioned in the cylinder body, one end of the first connecting rod 31 is connected with the piston 30, the other end of the first connecting rod 31 is connected with one end of the transmission mechanism 6, the other end of the transmission mechanism 6 is connected with the first motor 5, and at least one friction pair of the transmission mechanism 6 adopts a rolling bearing; the guide rail 4 is sleeved on the first connecting rod 31, the guide rail 4 is connected with the inner wall of the cylinder body, and the guide rail 4 is provided with a bearing for guiding the linear motion of the piston assembly 3.

A clearance seal and/or a complete seal is adopted between the piston assembly 3 and the inner wall of the cylinder body. When only gap sealing is adopted, the piston assembly 3 is not contacted with the inner wall of the cylinder body, the outer wall of the piston 30 and the inner wall of the cylinder body are sealed by the gap, the piston assembly 3 and the cylinder body shown in fig. 1 are sealed by the gap, and the sealing gap is thatWhen only full sealing is adopted, the outer wall of the piston 30 and the inner wall of the cylinder body are sealed by medium contact; when the gap seal and the complete seal are adopted, the gap seal is formed between the outer wall of the piston 30 and the inner wall of the cylinder, and the first connecting rod 31 is sleeved with a structural member and is completely sealed with the inner wall of the cylinder through the structural member, so that the following embodiments will be described in detail.

Preferably, the clearance between the outer wall of the piston 30 and the inner wall of the cylinderIs 1 μm-100 μm, preferably gap +.>Between 5 μm and 50 μm. In another preferred implementation manner, referring to fig. 2 of the specification, the piston assembly 3 of the present embodiment adopts a combined structure of the piston 30 and the first connecting rod 31, the piston assembly 3 includes a piston and a piston pin, the guide rail 4 includes a bearing and a bearing mounting seat, the bearing of the guide rail 4 is located in the bearing mounting seat, the bearing mounting seat is connected with the inner wall of the cylinder, preferably, the bearing mounting seat is fixedly connected with the inner wall of the cylinder, a round hole can be formed in the inner wall of the cylinder in a connection manner, the bearing mounting seat is provided with an internal threaded hole matched with the bearing mounting seat, the bearing mounting seat penetrates into the round hole of the inner wall of the cylinder through a bolt and is fixedly connected with the internal threaded hole of the bearing mounting seat, the piston pin penetrates into the mounting hole of the piston to be fixed, the piston is located in the bearing of the guide rail 4 and is connected with the transmission mechanism 6. Those skilled in the art will appreciate that there are a variety of ways in which the piston assembly 3, rail 4 and transmission 6 may be connected, including but not limited to the two types of solid matter described aboveThe present mode is as follows.

At least one end of the piston assembly 3 is a working cavity, and the exhaust valve 1 and the intake valve 2 are communicated with the working cavity. The exhaust valve 1 and the intake valve 2 of the present embodiment are mounted on a cylinder or a piston, and the exhaust valve 1 and the intake valve 2 are active control valves for opening and closing, that is, the opening and closing of the exhaust valve 1 and the intake valve 2 are controllable or have timing mechanisms, and the opening and closing of the valves are controlled by means of electric, mechanical, hydraulic or the like and according to needs, and the mechanical means may be cams or other means. The timing mechanism controls the opening and closing of the exhaust valve 1 and the intake valve 2 according to the movement angle or position of the piston 202.

Preferably, the ratio of exhaust pressure to intake pressure in the working chamber is 1.5-5.

Preferably, the ratio of the maximum flow area of the gas of the exhaust valve 1 and the intake valve 2 to the piston area is 0.1 to 0.5, and the piston area is calculated based on the piston diameter.

Taking an electrical control as an example, the active opening and closing of the intake valve 2 will be described. Referring to fig. 3 of the specification, fig. 3 (a) is an opened state of the air inlet valve 2, fig. 3 (b) is a closed state of the air inlet valve 2, the air inlet valve 2 is composed of a sealing plate C2, a telescopic motor C3 and an air pipe, the telescopic motor C3 is mounted on the outer side of the cylinder C1, the telescopic motor C3 is controlled by an external controller, a telescopic rod of the telescopic motor C3 is connected with the sealing plate C2, and the sealing plate C2 is provided with a through hole communicated with an air inlet hole of the cylinder C1, and the through hole is connected with the air pipe. The through hole on the sealing plate C2 is driven to close and communicate the air inlet hole of the cylinder body C1 through the expansion motor C3, so that the active opening and closing of the air inlet valve 2 are realized, and the air outlet valve 1 and the air inlet valve 2 have the same active opening and closing structure.

It will be appreciated by those skilled in the art that there are various structures for actively opening and closing the exhaust valve 1 and the intake valve 2 by electrically controlling them, and the above structures are merely examples, and the present invention is not limited to the structures for actively opening and closing the exhaust valve 1 and the intake valve 2, as long as they can actively open and close the exhaust valve and the intake valve 2.

The transmission mechanism 6 is driven by the first motor 5, the transmission mechanism 6 further drives the piston assembly 3 to reciprocate linearly along the inner wall of the cylinder body, when the exhaust valve 1 is closed and the air inlet valve 2 is opened, the piston assembly 3 moves downwards to suck the air of the air inlet valve 2 externally connected pipeline into the working cavity, and when the exhaust valve 1 is opened and the air inlet valve 2 is closed, the piston assembly 3 moves upwards to discharge the air sucked into the working cavity into the externally connected pipeline through the exhaust valve 1.

In a preferred implementation manner, the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston in the opening process of the air inlet valve 2 is between 10% and 50%, and further, the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston in the opening process of the air inlet valve 2 is between 25% and 35%.

In the preferred implementation mode, the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston is between 10 and 50 percent in the opening process of the exhaust valve 1, and further, the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston is between 15 and 35 percent in the opening process of the exhaust valve 1.

By adopting the structure of the embodiment, compared with the traditional reciprocating piston device, the air inlet and outlet valve is passive, namely, the opening and closing of the air inlet and outlet valve are realized under the action of pressure difference at two ends of the valve, so that larger irreversible loss is generated in the air inlet process and the air outlet process, and the air inlet valve 1 and the air inlet valve 2 of the high-efficiency reciprocating piston device are actively controlled, thereby avoiding air inlet and outlet throttling loss, air and cylinder wall heat exchange loss, leakage loss and friction loss; the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston in the opening process of the air inlet valve 2 and the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston in the opening process of the air outlet valve 1 are preset, so that smaller air inlet and outlet losses can be realized; in a conventional reciprocating piston device, the piston and the wall surface of the cylinder are usually sealed by a piston ring, and the piston ring is tightly attached to the wall surface of the cylinder due to the action of sealing medium force, so that larger friction loss is generated between the piston ring and the wall surface of the cylinder, and in the reciprocating piston device such as an internal combustion engine, the friction loss between the piston ring and the wall surface of the cylinder accounts for 50% -70% of all friction loss, therefore, the efficient reciprocating piston device of the embodiment adopts a gap Sealing or complete sealing is not adopted, and is very important for reducing friction loss and realizing high efficiency of the reciprocating piston device, and leakage loss caused by clearance sealing adopted by a piston ring can be reduced through higher operation frequency, or leakage is completely isolated by adopting complete sealing; by lubricating the friction pair between the piston 30 and the wall surface of the cylinder body and inside the transmission mechanism 6 through lubricating oil inside the cylinder body, the guide rail 4 is adopted to realize the reciprocating linear motion of the piston 30, compared with the friction motion between the piston ring and the wall surface of the cylinder body on the piston with the traditional structure, the lateral force generated by the transmission mechanism 6 is transferred between the piston 30 and the guide rail 4 by the traditional application between the piston 30 and the wall surface of the cylinder body, compared with the traditional structure, the friction loss is reduced under the same lateral force due to lower friction coefficient of the bearing.

Example 2:

referring to fig. 4-5 of the drawings, on the basis of embodiment 1, the connecting end of the first link 31 to the transmission mechanism 6 has a pin arranged transversely. The transmission 6 may be a crank link, diamond drive or the like, and fig. 4-5 show a crank link transmission 6, the transmission 6 comprising a second link 60 and a crank 61.

The second link 60 has bearings at both ends thereof, and the bearings at both ends thereof are fixed by the link shoes of the second link 60. The crank 61 adopts a shape like a Chinese character 'ji' with its top and bottom ends parallel. One end of the second connecting rod 60 is sleeved on the pin shaft of the first connecting rod 31 through a bearing and is in rotary connection with the pin shaft, and the other end of the second connecting rod 60 is sleeved on the top of the crank 61 through a bearing and is in rotary connection with the crank. One end of the bottom of the crank 61 is connected with an output shaft of the first motor 5, and the first motor 5 reciprocally rotates according to a preset angle, so as to drive the crank 61 to axially rotate.

Preferably, at least one friction pair of the transmission mechanism 6 adopts a rolling bearing, namely, at least one bearing at two ends of the crank 61 adopts a rolling bearing, and preferably, the bearings at two ends of the crank 61 adopt a rolling bearing.

By adopting the structure of the crank 61 in the shape of the Chinese character 'ji', the axial rotary motion of the crank 61 can be converted into the reciprocating linear motion of the second connecting rod 60, and then the piston assembly 3 is driven to reciprocate in the cylinder body.

Example 3:

referring to fig. 6 of the drawings, in the embodiment 1, the guide rail 4 has a bearing, and is fitted over the first link 31 via the bearing.

The bearings of the guide rail 4 may be rolling bearings or sliding bearings. Fig. 6 (a) and 6 (b) show the structure of two types of rolling bearings, and fig. 6 (c) shows the structure of one type of sliding bearing. Taking the example shown in fig. 6 (a), the bearings of the guide rail 4 have two symmetrically arranged bearings each including an outer ring, rollers and an inner ring, the bearings of the guide rail 4 are fixed to the inner wall of the cylinder body through the inner rings, and both sides of the first link 31 are in contact with the outer ring of each bearing. Taking fig. 6 (b) as an example, the bearing of the guide rail 4 includes rollers and a bracket, the bracket is fixed on the inner wall of the cylinder, the bracket has a central hole, a plurality of rollers are distributed on the inner side of the central hole of the bracket and are rotatably connected with the rollers, the central axis of each roller is perpendicular to the central axis of the bracket, and the first connecting rod 31 passes through the central axis of the bracket to contact with the rollers. Taking fig. 6 (c) as an example, the bearing of the guide rail 4 includes a sliding shaft and a bracket, the bracket is fixed on the inner wall of the cylinder, the bracket and the sliding shaft are both provided with a central hole, the sliding shaft is located in the central hole of the bracket and is connected with the sliding shaft along the axial direction of the sliding shaft, the central hole of the sliding shaft is coaxial with the central hole of the bracket, and the first connecting rod 31 passes through the central shaft of the sliding shaft and contacts with the central shaft of the sliding shaft.

Further, to reduce the sealing gap between the outer wall of the piston 30 and the inner wall of the cylinderAt least 1 ring groove 300 is provided in the outer wall circumferential ring of the piston 30, referring to the ring groove 300 shown in fig. 6 (c).

With this structure of the present embodiment, the rolling bearing has a significantly smaller friction coefficient than the sliding bearing, so that the bearing in the guide rail 4 is preferably a rolling bearing; the piston 30 at the clearance fit position with the cylinder is provided with a plurality of ring grooves 300, so that the sealing medium forms vortex in the ring grooves 300 to generate resistance, and leakage is reduced. The piston 30 at the clearance fit position of the cylinder can be provided with a plurality of convex rings, the convex rings are made of different materials from the piston, and the convex rings can be made of wear-resistant or better lubricating materials, so that on one hand, the purpose of lubrication is achieved, and the resistance generated by vortex can be formed among the convex rings, so that leakage is reduced.

Example 4:

referring to fig. 7-12 of the drawings, the high efficiency reciprocating piston type device of this embodiment further comprises an elastic member on the basis of embodiment 1.

The elastic element is provided with at least two structures, namely a first elastic element 8a and a second elastic element 8b, wherein the first elastic element 8a or the second elastic element 8b is matched with the piston assembly 3 to form a liquid cavity, one surface of the elastic element is contacted with working medium gas in the working cavity, and the other surface of the elastic element is contacted with liquid in the liquid cavity.

The elastic element is a corrugated pipe or a diaphragm.

Taking the example of fig. 7-9, a complete seal is employed between the outer wall of the piston 30 and the inner wall of the cylinder. The upper and lower ends of the first elastic element 8a are penetrated, one end of the first elastic element is in sealing connection with the piston assembly 3, and the other end of the first elastic element is in sealing connection with the cylinder body side. In order to reduce heat exchange losses, the inner side surface of the first elastic element 8a is in contact with working medium gas in the working chamber, and the outer side surface is in liquid contact with the liquid in the liquid chamber.

When adopting completely sealed, the cylinder body inner wall has annular restriction cylinder 7, and annular restriction cylinder 7 can adopt cast mode and cylinder body integrated into one piece, can adopt alone annular cylinder, through seting up the round hole at the cylinder body outer wall, and the internal thread hole of matching is seting up to annular restriction cylinder 7's outer wall, fixes annular restriction cylinder 7 in the cylinder body settlement position through the bolt.

One end of the first elastic element 8a of the present embodiment is connected with the top of the piston 30 in a sealing manner, and the other end is connected with the inner side of the top of the cylinder in a sealing manner. The first link 31 has a horizontally disposed flange whose outer wall is matched to the annular restrictor cylinder 7 with a gap therebetween, as shown in fig. 7Through gap->The flange headspace of the first link 31 is sealed. The liquid cavity formed by the top of the flange plate of the first connecting rod 31, the inner wall of the annular flow-limiting cylinder 7, the inner wall surface of the cylinder body and the outer wall of the first elastic element 8a is used for accommodating sealing medium, and the sealing medium adopts lubricating oil A.

When the piston 30 moves upwards, the flange of the first link 31 presses the sealing medium, the top of the piston 30 compresses the first elastic element 8a, so that the gas entering the first elastic element 8a from the inlet valve 2 is pressed out through the outlet valve 1, and a small amount of sealing medium is discharged from the gap under pressureThe way such as volatilize or splash contacts with the surface of guide rail 4 to play the lubrication action to the bearing of guide rail 4, reduce friction loss, promote life-span, because the isolation of first elastic element 8a, the sealing medium of lubrication bearing can not get into the working chamber, pollutes the working medium. The bearings of the guide rail 4 can also be directly lubricated by oil injection by an oil pump.

In a preferred embodiment, the guide rail 4 can be directly lubricated by a lubricant, the lubricant can be liquid lubricating oil or solid lubricating grease, and the guide rail 4 can be isolated from contact of liquid in the liquid cavity by related isolation measures, and can also be lubricated by volatilization and sputtering contact of the leaked liquid in the liquid cavity.

Preferably, the gapFrom 1 μm to 100. Mu.m, further, preferably a gap +.>Between 5 μm and 50 μm.

Preferably, the outer wall of the flange of the first link 31 has at least one circumferential groove, which causes the sealing medium in the liquid chamber to form a vortex therein to generate resistance, reducing leakage.

Taking the example of fig. 10-11, a clearance seal and a full seal are simultaneously employed between the outer wall of the piston 30 and the inner wall of the cylinder. One surface of the second elastic element 8b is in contact with the liquid in the liquid cavity, and the other surface is in contact with the working medium gas in the working cavity.

The efficient reciprocating piston device of the embodiment further comprises a sliding block 9 and a sliding rail 10, wherein the sliding block 9 and the sliding rail 10 are of annular cylindrical structures, the sliding block 9 is arranged in a central hole of the sliding rail 10 in a penetrating mode and is in sliding connection with the sliding rail 10, the sliding rail 10 is fixed with a cylinder body, a first connecting rod 31 is arranged in the central hole of the sliding block 9 in a penetrating mode, a second elastic element 8b is sleeved on the first connecting rod 31 and is located above the sliding block 9, one end of the second elastic element 8b is connected with the piston assembly 3, and the other end of the second elastic element 8b is connected with the sliding rail 10.

The first connecting rod 31 and the sliding block 9 in this embodiment adopt a split design, the connection mode is interference fit or screw fastening, etc., and in another implementation mode, the first connecting rod 31 and the sliding block 9 may be integrally formed.

The second elastic element 8b is internally provided with a sealing medium (such as lubricating oil), when the piston 30 moves upwards, one end of the second elastic element 8b is driven by the first connecting rod 31 to stretch, meanwhile, the first connecting rod 31 drives the sliding block 9 to move upwards in the sliding groove of the sliding rail 10, the upward movement of the sliding block 9 ensures that the volume of the second elastic element 8b is basically unchanged, and the top surface of the piston 30 compresses working medium, so that the working medium is discharged from the exhaust valve 1. Similarly, when the piston 30 moves downwards, the movement of the slider 9 in the sliding groove of the sliding rail 10 ensures that the volume of the second elastic element 8b is substantially unchanged, and the working chamber volume becomes larger, so that working medium is sucked from the air inlet valve 2.

By adopting the structure of the embodiment, when the fit clearance between the piston and the cylinder is between 1 mu m and 100 mu m, the problem of larger friction loss caused by friction between the piston and the cylinder in the operation process possibly exists due to the influences of frequency, processing, assembly and the like between the piston and the cylinder, and when the fit clearance is larger, the leakage loss of working medium between the piston and the cylinder is larger, so that the piston of the efficient reciprocating piston device is completely sealed by adopting the elastic element, the leakage loss of working medium at the matched position of the piston can be eliminated, the friction between the piston and the cylinder at the matched clearance caused by the matched clearance between the piston and the cylinder can be completely eliminated, even if the elastic element, the cylinder and the piston form a liquid cavity, the liquid cavity is filled with oil, and after the elastic element is adopted, the piston and the cylinder have the matched clearance of sealing oil, on the one hand, good lubrication can be generated due to the fact that the matched clearance is leaked or volatilized, on the other hand, the viscosity coefficient of the lubricating oil is high, the leakage loss is mainly the loss of work under the same pressure difference, and the efficiency loss caused by leakage quality is much smaller than the leakage loss of working medium, and the whole friction loss is much smaller.

Example 5:

the inventors of the present application found that: for a reciprocating piston device, heat exchange loss is the main loss, and because the heat exchange loss is also related to the pressure ratio, the smaller the pressure ratio is, the smaller the temperature difference between an inlet and an outlet of the reciprocating piston device is, and therefore, the smaller the temperature difference between a working medium and a cylinder wall surface is, and the smaller the heat exchange loss between the cylinder and the wall surface is; in order to achieve high efficiency of the heat pump energy storage system based on the reciprocating piston device, a regenerator is adopted to promote power consumption of the compressor under the low pressure ratio, namely, low-temperature working medium from a low-temperature heat exchanger is heated after passing through the regenerator, so that the temperature of the working medium entering the compressor is greatly improved, preferably, the temperature of the low-temperature working medium from the low-temperature heat exchanger is increased by more than or equal to 70 ℃ after passing through the regenerator, therefore, the compression work required by the working medium under the low pressure ratio is also greatly improved, and therefore, the reciprocating piston compressor with low heat exchange loss and the high-efficiency heat pump energy storage efficiency under the low pressure ratio are realized.

Referring to fig. 12 of the drawings, this embodiment provides a heat pump energy storage system employing a high-efficiency reciprocating piston device, which includes all the structures of the above embodiments, and further includes a high-temperature heat exchanger B1, an expander B2, a low-temperature heat exchanger B3, and a compressor B4. The high temperature heat exchanger B1, the expansion machine B2, the low temperature heat exchanger B3 and the compressor B4 are connected in sequence according to the state of FIG. 12 through pipelines. At least one of the expander B2 and the compressor B4 is a high-efficiency reciprocating piston device, and the other can be a high-efficiency reciprocating piston device or a turbine device.

Preferably, both the intake valve and the exhaust valve of the reciprocating piston device have active control functions of opening and closing. Preferably, the compressor B4 and the expander B2 in the energy storage process of the heat pump energy storage system adopt efficient reciprocating piston devices.

Example 6:

referring to fig. 13 of the specification, on the basis of example 5, the heat pump energy storage system using the efficient reciprocating piston device further includes a regenerator B5.

The high-temperature working medium flowing out of the high-temperature heat exchanger B1 exchanges heat with the low-temperature working medium flowing out of the low-temperature heat exchanger B3 in the heat regenerator B5, the high-temperature working medium is cooled after passing through the heat regenerator B5, and the low-temperature working medium is heated after passing through the heat regenerator B5, so that the inlet temperature of the compressor B4 is greatly improved.

Further, the inlet temperature of the compressor B4 is more than or equal to 100 ℃ under rated working conditions, and/or the ratio of the exhaust pressure to the inlet pressure of the compressor B4 is between 1.5 and 5, preferably between 2 and 3.

Preferably, the inlet temperature of the compressor B4 under rated working conditions is more than or equal to 100 ℃ and the ratio of the exhaust pressure to the inlet pressure of the compressor B4 is between 1.5 and 5, preferably the ratio of the exhaust pressure to the inlet pressure is between 2 and 3.

The high-temperature heat exchanger and the low-temperature heat exchanger can be heat exchange devices or heat storage devices, wherein the heat exchange devices are devices for exchanging heat between working media such as argon, helium, CO2 and the like and heat transfer fluids such as lubricating oil, water and the like, and the heat storage devices are devices for directly exchanging heat between the working media and the heat storage media and storing energy. The rated operating condition refers to the rated power or the operating condition under the highest system efficiency.

In the heat pump energy storage system, because the high temperature is higher and the low temperature is lower, lubricating oil cannot be usually contained, and therefore, friction pairs between pistons and cylinder wall surfaces in a traditional compressor and an expander and in a transmission mechanism are usually dry friction, so that friction loss is large.

The foregoing is merely exemplary embodiments of the present invention, and specific structures and features that are well known in the art are not described in detail herein. It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims (10)

1. A high-efficiency reciprocating piston device comprises an exhaust valve (1), an intake valve (2), a piston assembly (3), a transmission mechanism (6) and a cylinder body; characterized by also comprising a guide rail (4);

the piston assembly (3) and the transmission mechanism (6) are positioned in the cylinder body, and the bottom of the piston assembly (3) is connected with the transmission mechanism (6); the guide rail (4) is provided with a bearing, the piston assembly (3) is contacted with the bearing of the guide rail (4), and the guide rail (4) is connected with the inner wall of the cylinder body;

The exhaust valve (1) and/or the air inlet valve (2) are/is an opening and closing active control valve, and the exhaust valve (1) and the air inlet valve (2) are communicated with the working cavity;

and a clearance seal and/or a complete seal is adopted between the piston assembly (3) and the inner wall of the cylinder body.

2. A high efficiency reciprocating piston device according to claim 1, characterized in that the clearance between the piston outer wall and the cylinder inner wall of the piston assembly (3) is 1-100 μm.

3. The efficient reciprocating piston device as claimed in claim 1, further comprising a first motor (5), the first motor (5) being connected to a transmission mechanism (6), at least one friction pair of the transmission mechanism (6) being a rolling bearing;

and/or the bearings of the guide rail (4) are rolling bearings.

4. The efficient reciprocating piston device according to claim 1, characterized in that the ratio of the maximum flow area of the working medium to the area corresponding to the piston diameter is between 10% and 50% during the opening of the inlet valve (2);

and/or, in the opening process of the exhaust valve (1), the ratio of the maximum flow area of the working medium to the area corresponding to the diameter of the piston is between 10 and 50 percent.

5. A high efficiency reciprocating piston device as recited in claim 1 wherein the ratio of exhaust pressure to intake pressure in the working chamber is 1.5-5.

6. The efficient reciprocating piston device according to claim 1, further comprising an elastic element, wherein the elastic element and the piston assembly (3) are further matched to form a liquid cavity, one surface of the elastic element is contacted with working medium gas in the working cavity, and the other surface of the elastic element is contacted with liquid in the liquid cavity;

the elastic element is a corrugated pipe or a diaphragm.

7. A high efficiency reciprocating piston device as claimed in claim 6, characterized in that the elastic element has at least two structures, a first elastic element and a second elastic element, respectively, said first elastic element or said second elastic element being mounted in cooperation with the piston assembly (3).

8. The efficient reciprocating piston device as defined in claim 7, wherein the upper and lower ends of the first elastic element are penetrated, one end of the first elastic element is in sealing connection with the piston assembly (3), the other end of the first elastic element is in sealing connection with the cylinder side, the inner side surface of the first elastic element is in contact with working medium gas in the working chamber, and the outer side surface of the first elastic element is in contact with liquid in the liquid chamber;

the second elastic element is sleeved on the rod part of the piston assembly (3) and is positioned above the sliding block with the central hole, the piston assembly (3) is fixedly arranged in the central hole of the sliding block in a penetrating manner, the sliding block is arranged in the sliding rail with the central hole in a penetrating manner and is in sliding contact with the sliding rail, one end of the second elastic element is connected with the piston assembly (3), the other end of the second elastic element is connected with the sliding rail, one surface of the second elastic element is in liquid contact with the liquid in the liquid cavity, and the other surface of the second elastic element is in contact with working medium gas in the working cavity.

9. The efficient reciprocating piston device according to claim 7, characterized in that one end of a rod part of the piston assembly (3) is connected with the piston, the other end is connected with the transmission mechanism (6), a bearing of the guide rail (4) is sleeved on the connecting rod, and the rod part is provided with a flange plate which is horizontally arranged;

the cylinder body inner wall has annular current limiting cylinder, the ring flange is located annular current limiting cylinder inboard, have the clearance between ring flange outer wall and the inner wall of annular current limiting cylinder.

10. The heat pump energy storage system adopting the efficient reciprocating piston device is characterized by comprising a high-temperature heat exchanger, an expander, a low-temperature heat exchanger, a compressor, a second motor and a heat regenerator;

at least one of the expander and the compressor employing a high efficiency reciprocating piston device as defined in claims 1-9; the inlet temperature of the compressor under the rated working condition is more than or equal to 100 ℃ and/or the ratio of the exhaust pressure to the inlet pressure of the compressor is 1.5-5.