CN112460825A

CN112460825A - Single-piston compressed air refrigeration cycle device

Info

Publication number: CN112460825A
Application number: CN202011265074.XA
Authority: CN
Inventors: 裴建生
Original assignee: Research Center Of Water Resources And Ecological Water Conservancy Engineering In Cold And Arid Areas Of Xinjiang Uygur Autonomous Region Academician And Expert Workstation
Current assignee: Research Center Of Water Resources And Ecological Water Conservancy Engineering In Cold And Arid Areas Of Xinjiang Uygur Autonomous Region Academician And Expert Workstation
Priority date: 2020-11-12
Filing date: 2020-11-12
Publication date: 2021-03-09

Abstract

The invention relates to the technical field of thermal energy power machinery, in particular to a single-piston compressed air refrigeration cycle device which comprises a cylinder, a piston, a heat exchanger and power equipment capable of driving the piston to reciprocate. The device has high energy efficiency ratio, light structure, low manufacturing cost, safety and environmental protection, is suitable for various places such as air temperature regulation, dehumidification and heating, water quantity in condensed water air, drying and the like, and provides a brand new technical scheme for the field of refrigeration cycle.

Description

Single-piston compressed air refrigeration cycle device

Technical Field

The invention relates to the technical field of thermal power machinery, in particular to a single-piston compressed air refrigeration cycle device.

Background

The refrigeration device in the field of heat energy power machinery is more and more emphasized by people, the refrigeration device is more and more widely used in life and industrial and agricultural production, particularly along with the improvement of the living standard of people, an air conditioner for air temperature regulation becomes indispensable equipment in life and production of people, at present, 10 to 30 percent of the electric energy of the whole society is consumed by the refrigeration device, the efficiency of the refrigeration device is also greatly concerned by people, and strict limitation regulations are put on the minimum energy efficiency ratio EER or COP of the produced refrigeration device.

The ideal thermodynamic cycle for a compression refrigeration unit is a reverse carnot cycle, the energy efficiency ratio of which depends on the temperature of the high and low temperature heat sources, such as: when the indoor air temperature is 25 ℃ and the outdoor air temperature is 35 ℃, the energy efficiency ratio EER of the ideal thermodynamic cycle device is =29.8kw/kw or COP =30.8 kw/kw, and the compression refrigeration cycle mainly has two forms, namely: the refrigeration device comprises a compressed air refrigeration cycle and a compressed vapor refrigeration cycle, wherein the compressed vapor refrigeration cycle utilizes the characteristic of large latent heat of vaporization of a refrigerant, so that the corresponding refrigeration device has strong refrigeration capacity, light equipment, high energy efficiency ratio and low manufacturing cost, and although the refrigeration device is influenced by heat transfer temperature difference in the equipment, imperfect thermodynamic cycle, friction loss of an air path and the like, the energy efficiency ratio can still reach between 3 kw/kw and 6 kw/kw under rated working conditions, so that the refrigeration device with the cycle becomes a main force of the refrigeration field, and the main defect of the refrigeration device is the damage of the refrigerant to the atmospheric environment.

The compressed air refrigeration cycle has the advantages that the working medium is air, the thermodynamic cycle is completed through four processes of compression, heat release, expansion and heat absorption of the air, the corresponding compression ratio is small, the theoretical energy efficiency of the cycle is high, the requirements of low-temperature users and high-temperature users can be met by adopting a regenerative cycle mode, and the whole cycle process is environment-friendly and safe. There are currently two main mechanisms to implement this thermodynamic cycle, namely: the main components of the impeller type compressed air refrigeration cycle device are a compression impeller and an expansion impeller, the compression impeller completes the compression of air through external force, the compressed air enters the expansion impeller after being externally released heat through a radiator, the expansion impeller releases cold air on one hand and recovers energy on the other hand, thereby completing the circulation, which has the advantages that the refrigerating capacity of the device is strong, the defects are limited by the mechanical efficiency of the compression impeller and the expansion impeller, the energy efficiency ratio of the whole circulation is not high, the mechanical energy consumed by the compression impeller and the expansion impeller in the circulation process is far more than the net work required by the circulation, therefore, even if the impeller with the highest mechanical efficiency is adopted, the energy efficiency ratio EER of the refrigerating device is generally between 1.5 and 2.0, and is difficult to exceed 3.0, this disadvantage makes such a refrigeration device usable only in special places where safety requirements are high.

The existing piston type compressed air refrigeration cycle equipment mainly comprises a compression cylinder, an expansion cylinder and a radiator, wherein the compression cylinder and the expansion cylinder have two strokes, the compression cylinder has two strokes of air suction and compression, the compression stroke is divided into two steps, the air suction valve is closed to compress air, the exhaust valve is opened to discharge the compressed air into the radiator to dissipate heat, the expansion cylinder is also the same, pistons of the two cylinders are connected to a crankshaft through a crank, the crankshaft is mechanically dragged to rotate to enable the pistons to continuously reciprocate, and the valves are sequentially opened and closed to complete the whole thermodynamic cycle. Compared with impeller type circulation equipment, the energy efficiency ratio of the impeller type circulation equipment is much smaller than that of compression steam refrigeration circulation equipment when the compression ratio is small, but the impeller type circulation equipment has the defects that the mechanical structure and the force transmission mode are complicated, the diameter and the stroke of a piston are not suitable to be manufactured to be large, the flow rate of the compression steam refrigeration circulation equipment is small, the refrigeration capacity of the compression steam refrigeration circulation equipment is low, the equipment is heavy, large in size and poor in economical efficiency, and therefore the compression steam refrigeration circulation equipment is rarely reused since the compression steam refrigeration circulation equipment is published.

Disclosure of Invention

The invention provides a single-piston compressed air refrigeration cycle device, which overcomes the defects of the prior art, can effectively overcome the defects of the prior piston compressed air refrigeration device, has the characteristics of high energy efficiency ratio, strong refrigeration capacity, light and handy structure, economy and practicality, and is suitable for the operation of dragging devices with various power sources.

The technical scheme of the invention is realized by the following measures: the utility model provides a single piston compressed air refrigeration cycle device, which comprises a cylinder, a piston, heat exchanger and the power equipment that can drive piston reciprocating motion, the piston suit is in the cylinder, the piston of suit in the cylinder divide into compression chamber and expansion chamber with the cylinder, be provided with admission valve and middle pneumatic valve No. one on the cylinder that the compression chamber corresponds, be provided with discharge valve and middle pneumatic valve No. two on the cylinder that the expansion chamber corresponds, the intercommunication has middle gas circuit pipeline between pneumatic valve in the middle of an and No. two, the heat exchanger intercommunication is on middle gas circuit pipeline.

The following is further optimization or/and improvement of the technical scheme of the invention:

the guide shaft is axially and fixedly arranged in the cylinder, the piston is sleeved in the cylinder through the guide shaft, and the guide shafts between the piston and the end covers on the two sides of the cylinder are respectively sleeved with the auxiliary springs.

The power equipment adopts a linear motor, and the power output end of the linear motor is fixedly connected with the dowel bar of the piston.

The power equipment adopts a parallel fan, a power pipeline is communicated on a middle air path pipeline between the heat exchanger and the first middle air valve, and the air outlet end of the parallel fan is communicated with the air inlet end of the power pipeline.

The power pipeline is communicated with an air storage tank.

The power equipment comprises a gas inlet end serial fan and a gas outlet end serial fan, wherein a gas outlet end of the gas inlet end serial fan is communicated with a gas inlet end of a gas inlet valve, and a gas inlet end of the gas outlet end serial fan is communicated with a gas outlet end of a gas outlet valve.

The heat exchanger adopts a water collecting tank which is communicated with the middle gas pipeline along the gas transmission direction of the middle gas pipeline, and a gas-water separator is arranged in the water collecting tank.

The heat exchanger adopts a heat regenerator, a primary side channel and a secondary side channel are arranged in the heat regenerator, the primary side channel of the heat regenerator is communicated with a middle gas pipeline along the gas transmission direction of the middle gas pipeline, an exhaust pipe is communicated between the gas inlet end of the secondary side channel of the heat regenerator and an exhaust valve, a second water collecting tank is communicated on the exhaust pipe, and a gas-water separator is arranged in the second water collecting tank.

The cylinder is a vertical cylinder.

The device overcomes the defects that the crank of the compression cylinder continuously receives mechanical force transmitted by the crank and the expansion cylinder continuously releases expansion work to the crank in the circulation process of the existing compressed air refrigeration circulation equipment, so that the equipment has large volume and low refrigeration capacity.

Drawings

FIG. 1 is a schematic diagram of the basic structure of the present invention.

FIG. 2 is a schematic structural diagram of the piston structure optimized and dragged by a parallel fan.

FIG. 3 is a schematic structural view of the piston structure optimized and dragged by a series fan according to the present invention.

FIG. 4 is a schematic diagram of the basic structure of the present invention during the dehumidification, dehumidification heating and drying cycle.

FIG. 5 is a schematic diagram of the basic structure of the present invention when the regenerative cycle of the regenerator is used.

The codes in the figures are respectively: the air compressor comprises a cylinder 1, a piston 2, an air inlet valve 3, a first intermediate air valve 4, an exhaust valve 5, a second intermediate air valve 6, a heat exchanger 7, a linear motor 8, a user chamber 9, a guide shaft 10, an auxiliary spring 11, a parallel fan 12, a gas storage tank 13, a serial fan 14 at an air inlet end, a serial fan 15 at an exhaust end, a first water collecting tank 16, a heat regenerator 17, a second water collecting tank 18, a power pipeline 19, a compression cavity 20, an expansion cavity 21, an intermediate air pipeline 23, an air inlet pipe 24 and an exhaust pipe 25.

Detailed Description

The present invention is not limited by the following examples, and specific embodiments may be determined according to the technical solutions and practical situations of the present invention.

In the present invention, for convenience of description, the description of the relative positional relationship of the components is described according to the layout pattern of fig. 1 of the specification, such as: the positional relationship of front, rear, upper, lower, left, right, etc. is determined in accordance with the layout direction of fig. 1 of the specification.

The invention is further described below with reference to the following examples:

as shown in the attached drawing 1, the single-piston compressed air refrigeration cycle device comprises a cylinder (1), a piston (2), a heat exchanger (7) and power equipment capable of driving the piston (2) to reciprocate, wherein the piston (2) is sleeved in the cylinder (1), the piston (2) sleeved in the cylinder (1) divides the cylinder (1) into a compression cavity (20) and an expansion cavity (21), an air inlet valve (3) and a first intermediate air valve (4) are arranged on the cylinder (1) corresponding to the compression cavity (20), an exhaust valve (5) and a second intermediate air valve (6) are arranged on the cylinder (1) corresponding to the expansion cavity (21), an intermediate air path pipeline (23) is communicated between the first intermediate air valve (4) and the second intermediate air valve (6), and the heat exchanger (7) is communicated on the intermediate air path pipeline (23).

When the device is used, the air inlet end of the air inlet valve (3) is communicated with the user chamber (9), and the air outlet end of the exhaust valve (5) is communicated with the user chamber (9).

In the device, in a thermodynamic cycle, a cylinder (1), an air inlet valve (3) and a first intermediate air valve (4) play the role of a compression cylinder, and the cylinder (1), an air outlet valve (5) and a second intermediate air valve (6) play the role of an expansion cylinder and share a piston (2).

The device can provide cold and heat for a user room (9), and the cooling cycle process is described as follows: as shown in fig. 1, the piston (2) completes a thermodynamic cycle through two strokes of intake/exhaust and compression/expansion in a reciprocating motion, and when the piston (2) moves from left to right, the compression cylinder (compression chamber) sucks relatively hot gas of the user chamber (9) through the intake valve (3), and simultaneously, the expansion cylinder (expansion chamber) discharges relatively cold air to the user chamber (9) through the exhaust valve (5), thereby completing the intake/exhaust strokes; when the piston (2) moves from right to left, the compression cylinder receives external force transmitted by the piston (2) to compress gas, the compressed air is heated and sent to the heat exchanger (7) through the first intermediate air valve (4) to be cooled, meanwhile, the expansion cylinder introduces the cooled compressed air through the second intermediate air valve (6), when the piston (2) moves to a certain proper position, the intermediate air valve (6) is closed, the gas adiabatically expands in the expansion cylinder, and the temperature is reduced, so that the whole cycle is completed.

The heat supply cycle process of the device is similar to the cold supply cycle, and the main difference between the heat supply cycle process and the cold supply cycle process is that the air pressure in the heat exchanger (7) is in a positive pressure state, and the air pressure in the cold supply cycle process is in a negative pressure state.

In the thermodynamic cycle process, air compression and expansion processes are synchronously performed, and expansion work is directly transmitted to a compression cylinder through a piston (2) to become one of the most main energies of compressed air, so that a stressed member of the device is greatly simplified, and the structure of the device becomes light and handy.

The following are further optimizations or/and improvements to the single piston compressed air refrigeration cycle apparatus described above:

as shown in the attached figure 2, a guide shaft (10) is axially and fixedly arranged in a cylinder (1), a piston (2) is sleeved in the cylinder (1) through the guide shaft (10), and auxiliary springs (11) are respectively sleeved on the guide shaft (10) between the piston (2) and end covers at two sides of the cylinder (1).

In order to further increase the refrigerating capacity of the device and reduce the volume of the device, a guide shaft (10) can be arranged in the cylinder (1) so that the piston (2) reciprocates along the guide shaft (10); the auxiliary spring (11) is arranged to enable the movement of the piston (2) to have rhythm, prevent the piston from colliding with a cylinder, and control the movement period and the corresponding linear speed of the piston (2) so as to adapt to various power dragging.

As shown in attached figures 1 and 4, the power equipment adopts a linear motor (8), and the power output end of the linear motor (8) is fixedly connected with a dowel bar of a piston (2).

The refrigeration cycle device using the linear motor (8) as power equipment has the advantages of reliable method and simple control of each air valve, and only needs to connect the dowel bar on the piston (2) with the linear motor (8), thereby having the defects of large volume and heavy weight of the equipment and simultaneously not being suitable for further increasing the stroke of the piston (2).

As shown in the attached figure 2, the power equipment adopts a parallel fan (12), a power pipeline (19) is communicated on a middle gas circuit pipeline (23) between a heat exchanger (7) and a first middle gas valve (4), and the gas outlet end of the parallel fan (12) is communicated with the gas inlet end of the power pipeline (19).

The refrigeration cycle device adopts the higher-pressure parallel fan (12) to drag, when the dragging scheme is adopted, the parallel fan (12) needs to be connected on the middle gas circuit pipeline (23) in parallel, the indirect dragging mode is adopted, the parallel fan (12) is used for sucking air from the outside and directly entering the middle gas circuit pipeline (23), and in the compression/expansion stroke of the piston (2), the expansion work is increased by increasing the air input of the expansion cylinder, so that the expansion work and the compression work are balanced, and the cycle is forced to be continuously carried out.

As shown in figure 2, in order to stabilize the air pressure, an air storage tank (13) is communicated with the power pipeline (19).

As shown in the attached figure 3, the power equipment comprises a fan (14) connected with the air inlet end in series and a fan (15) connected with the air outlet end in series, wherein the air outlet end of the fan (14) connected with the air inlet end of the air inlet valve (3) in series is communicated with the air outlet end of the air outlet valve (5) in series, and the air inlet end of the fan (15) connected with the air outlet end of the air outlet valve (5) in series.

When the dragging scheme is adopted, a medium pressure fan (14) connected in series with an air inlet and an air outlet is required to be arranged on an air inlet pipe (24), and a fan (15) connected in series with an air outlet is arranged on an air outlet pipe (25), and the indirect dragging mode is also adopted, and the surplus energy of the stroke is accumulated on an auxiliary spring (11) through the air inlet/air outlet stroke of a piston (2) and is discharged in the compression/expansion stroke, so that the expansion work and the compression work are balanced, and the circulation is forced to be continuously carried out.

As shown in fig. 4, the heat exchanger (7) adopts a first water collecting tank (16), the first water collecting tank (16) is communicated with the middle gas path pipeline (23) along the gas transmission direction of the middle gas path pipeline (23), and a gas-water separator is arranged in the first water collecting tank (16).

When the heat exchanger (7) adopts the first water collecting tank (16), the middle gas circuit pipeline (23) is in a negative pressure state, the pressure in the first water collecting tank (16) is lower than the atmospheric pressure, the gas temperature is reduced, the vapor in the air is condensed into liquid water, and the latent heat of gasification is released at the same time, so the exhaust temperature is higher than the inlet temperature, and the refrigeration cycle device can be used as dehumidification, dehumidification heating and drying type heat energy mechanical equipment.

A heat preservation layer can be arranged outside the water collecting gas tank (16), and a gas-water separator arranged inside the water collecting gas tank is used for separating gas from liquid water, and because the water collecting gas tank (16) is used for heat exchange, the required heat energy is the latent heat of vaporization of vapor in the air, the refrigeration cycle device is not only very simple and light in structure, but also higher in energy efficiency when the refrigeration cycle device is used for dehumidification heating and drying.

As shown in fig. 5, the heat exchanger (7) adopts a heat regenerator (17), a primary side channel and a secondary side channel are arranged in the heat regenerator (17), the primary side channel of the heat regenerator (17) is communicated with a middle gas path pipeline (23) along the gas transmission direction of the middle gas path pipeline (23), an exhaust pipe (25) is communicated between the gas inlet end of the secondary side channel of the heat regenerator (17) and the exhaust valve, a second water collecting tank (18) is communicated with the exhaust pipe (25), and a gas-water separator is arranged in the second water collecting tank (18).

This refrigeration cycle device is at middle gas circuit pipeline series connection regenerator (17) to form backheat formula air refrigeration cycle device, in order to further improve this device's efficiency, when this device was arranged in directly preparing the condensate water from the air, through No. two water collecting tank (18) storage condensate water, this circulation efficiency is high.

According to the requirement, the cylinder (1) is a vertical cylinder.

In the circulation process of the refrigeration cycle device, the main mechanical friction force is generated by the pressure of the gravity action of the piston (2) on the wall of the cylinder (1) or the guide shaft (10), and the refrigeration cycle device adopts a vertical structure (at the moment, a compression cavity (20) and an expansion cavity (21) are distributed up and down), so that the friction force can be basically eliminated, and the circulation efficiency is greatly improved.

Example 1: the single-piston compressed air refrigeration cycle device is used as a household air conditioner: the technical scheme that a guide shaft (10) and an auxiliary spring (11) are arranged is adopted in the air cylinder (1) of the embodiment, the technical scheme that a fan (12) is connected in parallel is adopted in a dragging mode, the heat exchanger (7) adopts the technical scheme of a conventional forced air cooling radiator, the three parts are combined into a main machine (shown in the attached drawing 2) which is integrally formed, the main machine is installed outdoors, and an air inlet pipe (24) communicated with an air inlet valve of the main machine and an exhaust pipe (25) communicated with an exhaust valve are communicated with a user room (9), so that an air conditioning system is.

In example 1, the diameter of the piston (2) is 40 cm, the net stroke is 80 cm, the designed average speed of the piston (2) is 2.0 m/s, the parallel fan (12) adopts a micro Roots fan, the design compression ratio is 1.3, the pressure in the cylinder (1) is considered to be small, meanwhile, the differential pressure of the piston (2) is zero in most of the running time, and is 0.3 kg/cm square only in a very short time, so except that the contact parts of the guide shaft (10), the auxiliary spring (11) and the piston (2) are made of metal materials, the rest of the air conditioner is made of hard plastic materials, so that the heat absorption and release amount in the circulation process is reduced, the theoretical temperature difference of air intake and exhaust is 21.9 ℃, the actual temperature difference is about 16-17 ℃, the refrigerating capacity is about 2000W, the air conditioner is equivalent to a small 1-piece air conditioner, the theoretical energy efficiency ratio EER =12.5, the COP =13.8, and the actual energy efficiency ratio is expected to exceed 4.0.

Example 2: this single piston compressed air refrigeration cycle device is as the dehumidification heating machine in the agricultural facility big-arch shelter: in the production process of the agricultural facility greenhouse, the roots of plants need to absorb liquid water in soil, and the leaf surfaces need to evaporate gaseous water to maintain the growth of crops, so that the maintenance of higher temperature and lower humidity in the greenhouse is often the key for the growth of crops in the greenhouse.

The purpose of this embodiment 2 is to provide a high-efficiency dehumidifying and heating machine for a greenhouse of an agricultural facility, the cylinder arrangement and the dragging manner in embodiment 2 are the same as those in embodiment 1, the diameter of the piston (2) is 50 cm, the net stroke is 100 cm, the piston (2) has a designed average speed of 2.0 m/s, but the heat exchanger is replaced by a water collecting tank (16), the middle gas pipeline (23) of the device is in a negative pressure state, gaseous water in low-temperature condensed air of the water collecting tank (16) is mainly used in the circulation process, and latent heat of gasification is released, the temperature difference between the inlet air and the exhaust air of this embodiment is 8 ℃, the designed compression ratio is 1.4, the theoretical energy efficiency ratio is up to 35, the actual energy efficiency ratio is expected to exceed 8.0, the condensing capacity is about 4.6kW, the amount of dehumidified water is about 6.7 kg/h, the amount of daily water production is about 134 kg, the daily power consumption is about 11 kw.h, and the heat exchange in the circulation mainly occurs, therefore, as long as the piston cylinder body and the first water collecting gas tank (16) are combined into a whole and are placed in the greenhouse, a power pipeline (19) is not required to be connected, the embodiment can be used for the agricultural facility greenhouse with the square length of about 150 to 250 square meters, and can provide a high-quality irrigation water source (provided by the condensed water of the first water collecting gas tank (16)) for the greenhouse while dehumidifying and heating the greenhouse, so that liquid water and gaseous water in the greenhouse can be continuously recycled, and self-sufficiency is basically realized, and the piston cylinder body has special significance and effect on the modern agricultural development in arid regions.

The device of embodiment 2 can also be used in other wide application fields, for example, it can be used in dryers in agriculture and processing industry, when the temperature of the drying room is required to be higher than 40 ℃, the main machine should be placed outdoors and connected with the drying room through the air inlet and outlet pipes, because most of the heat energy of the drying room is from the vaporization latent heat in the water vapor of the dried material, and only a small part of the heat energy is from the electric energy, therefore, only the heat preservation measure of the drying room is needed, compared with the existing dryers, the electric energy consumption is very small, and the temperature of the drying room is not only high, but also the temperature adjustment is very convenient.

It is to be noted that: in the thermodynamic cycle process of example 2, the exhaust pipe has a transient reverse flow phenomenon, in the design of the specific implementation scheme, the exhaust pipe is not suitable to be too long, the designed flow rate in the pipe is also as small as possible, and other necessary measures can be taken when necessary to avoid the cycle efficiency being influenced too much.

Example 3: the single-piston compressed air refrigeration cycle device is used as an air internal condensation water generator: the technical scheme for solving the problem of extremely water shortage is that liquid water is directly condensed from air, but the electric energy required to be consumed by the existing technical scheme is very huge, and the power consumption of single water is up to 200 kW.h/ton, so that the technical scheme is difficult to popularize and use.

In this embodiment 3, a regenerative cycle technical scheme is adopted, and the regenerative cycle of the device is realized by a regenerator (17) shown in fig. 5, thereby further improving the efficiency, in this embodiment, a cylinder arrangement scheme and a dragging mode are the same as those of embodiment 1, a piston technical scheme is the same as that of embodiment 2, when a designed temperature difference between intake and exhaust is 8 ℃, a designed compression ratio is 1.4, a theoretical energy efficiency ratio thereof is greater than 50, an actual energy efficiency ratio is expected to exceed 12.0, a condensing capacity is about 4.6kW, when an air temperature is higher than 25 ℃, and a relative humidity is greater than 60%, a water production capacity is about 6.7 kg/h, a daily water production is about 134 kg, and an electricity consumption of single water is expected to be lower than 55 kw.h/ton.

The embodiment can also be used for a dehumidifying, heating and drying machine in a greenhouse of agricultural facilities, and compared with the embodiment 2, the embodiment has the advantages of higher energy efficiency, no backflow phenomenon of an exhaust pipeline and complex heat regenerator (17).

In conclusion, the device overcomes the defects that the crank of the compression cylinder continuously receives mechanical force transmitted by the crankshaft and the expansion cylinder continuously releases expansion work to the crankshaft in the circulation process of the conventional compressed air refrigeration cycle equipment, so that the equipment has large volume and low refrigeration capacity.

The technical characteristics form an embodiment of the invention, which has strong adaptability and implementation effect, and unnecessary technical characteristics can be increased or decreased according to actual needs to meet the requirements of different situations.

Claims

1. The single-piston compressed air refrigeration circulating device is characterized in that a cylinder, a piston, a heat exchanger and power equipment capable of driving the piston to reciprocate are arranged in the cylinder in a sleeved mode, the piston sleeved in the cylinder divides the cylinder into a compression cavity and an expansion cavity, an air inlet valve and a first middle air valve are arranged on the cylinder corresponding to the compression cavity, an exhaust valve and a second middle air valve are arranged on the cylinder corresponding to the expansion cavity, a middle air path pipeline is communicated between the first middle air valve and the second middle air valve, and the heat exchanger is communicated on the middle air path pipeline.

2. The single-piston compressed air refrigerating cycle apparatus according to claim 1, wherein a guide shaft is fixedly installed in the cylinder in an axial direction, the piston is fitted in the cylinder through the guide shaft, and auxiliary springs are respectively fitted on the guide shafts between the piston and end caps on both sides of the cylinder.

3. A single piston compressed air refrigerating cycle apparatus as claimed in claim 1 or 2, wherein the power equipment employs a linear motor, and a power output end of the linear motor is fixedly connected with a dowel of the piston.

4. The single-piston compressed air refrigeration cycle device according to claim 1 or 2, wherein the power equipment adopts a parallel fan, a power pipeline is communicated with an intermediate air pipeline between the heat exchanger and the first intermediate air valve, and an air outlet end of the parallel fan is communicated with an air inlet end of the power pipeline.

5. The single-piston compressed air refrigeration cycle apparatus according to claim 4, wherein an air tank is connected to the power line.

6. The single-piston compressed air refrigeration cycle apparatus according to claim 1 or 2, wherein the power plant includes an inlet end series fan and an outlet end series fan, an outlet end of the inlet end series fan communicates with an inlet end of the inlet valve, and an inlet end of the outlet end series fan communicates with an outlet end of the outlet valve.

7. The single-piston compressed air refrigerating cycle apparatus according to claim 1, 2 or 5, wherein the heat exchanger employs a first water collecting tank, the first water collecting tank is communicated with the intermediate gas path pipeline along the gas transmission direction of the intermediate gas path pipeline, and a gas-water separator is provided in the first water collecting tank.

8. The single-piston compressed air refrigerating cycle apparatus according to claim 3, 4 or 6, wherein the heat exchanger employs a first water collecting tank, the first water collecting tank is communicated with the intermediate gas path pipeline along the gas transmission direction of the intermediate gas path pipeline, and a gas-water separator is provided in the first water collecting tank.

9. The single-piston compressed air refrigeration cycle device according to any one of claims 1 to 6, wherein the heat exchanger employs a regenerator, a primary side channel and a secondary side channel are provided in the regenerator, the primary side channel of the regenerator is communicated with the intermediate gas line along the gas transmission direction of the intermediate gas line, an exhaust pipe is communicated between the gas inlet end of the secondary side channel of the regenerator and the exhaust valve, a second water collecting tank is communicated with the exhaust pipe, and a gas-water separator is provided in the second water collecting tank.

10. The single piston compressed air refrigerating cycle apparatus as claimed in any one of claims 1 to 9, wherein the cylinder is a vertical cylinder.