CN220169700U - Carbon dioxide cascade refrigeration system with cold accumulation device - Google Patents

Abstract

The utility model discloses a carbon dioxide cascade refrigeration system with a cold accumulation device, which comprises a carbon dioxide low-temperature circulation system, a Freon high-temperature circulation system and a cold accumulation system; the water outlet of the cold accumulation device is divided into three branches through a pipeline, and the first branch is communicated with a water return pipe of the cold accumulation device to form a loop after heat exchange is carried out between the first branch and the high-temperature fresh-keeping warehouse/backwater through a heat exchanger by a first circulating water pump; the second branch is communicated with the cold accumulation device water return pipe through a second working medium pipeline of the auxiliary condenser by a second circulating water pump to form a loop; the third branch is connected with the cold accumulation device water return pipe through the second working medium pipeline of the subcooler by a third circulating water pump to form a loop. The utility model can solve the problems of large load fluctuation, unstable unit operation and high operation pressure; peak clipping and valley filling are carried out on the system, so that initial investment is reduced, and the running cost of the system is reduced; the carbon emission is directly reduced by more than 95 percent, and the method is environment-friendly, safe and efficient.

Description

Carbon dioxide cascade refrigeration system with cold accumulation device

Technical Field

The utility model relates to the technical field of refrigeration systems, in particular to a carbon dioxide cascade refrigeration system with a cold accumulation device.

Background

Traditional CO ₂ The cascade system, the low-temperature carbon dioxide system and the high-temperature freon system are matched according to the design working condition, the high-temperature and low-temperature stages are difficult to realize the optimal state of flow and cold energy matching under the starting working condition, the interstage matching characteristic between the high-temperature and low-temperature systems is lower, the carbon dioxide compressor is usually started, the cold energy of the freon system is insufficient to control the carbon dioxide pressure at the moment, or the cold energy of the high-temperature freon is larger than the condensation capacity of the low-temperature carbon dioxide in the starting stage, and the two conditions can lead to the unloading and stopping of the carbon dioxide compressor due to the overhigh exhaust pressure and the unloading and stopping of the freon compressor due to the overlow suction pressure; in addition, when the equipment is selected, the equipment is usually configured with the maximum load to cope with the least adverse working condition, so the equipment is excessively configured and the initial investment is excessively high, but in actual operation, most of the units are operated in a non-full-load state, and when the load suddenly increases or decreases, the system can only meet the change requirement of the load by means of frequently starting the compressor, so that the service life of the compressor is reduced, the energy waste is caused, and the operation cost is high.

The power consumption of the air conditioning system accounts for about 60% of the building power consumption, the power consumption peak period is in daytime, the power grid pressure load is increased, and huge pressure is brought to the supply of the power system; however, at night, the system belongs to a low electricity consumption period, the power supply quantity is larger than the required electric quantity, and the power supply quantity is larger than the required electric quantity, so that a large amount of energy sources are wasted, and the effect of peak clipping and valley filling is realized to a certain extent due to the appearance of the cold storage system.

The application of the cold accumulation system can balance peak-valley load of a power grid, utilize peak-valley electricity price, accumulate cold in the period of low electricity price, store cold energy in the form of cold water or solid ice, release the cold energy in the cold accumulation device in the period of high electricity consumption peak and high electricity price, bear part or all of load of a building, reduce running of a refrigerating unit, have the effect of saving running energy consumption cost of the refrigerating system, and in addition, can also reduce the start-stop times of a compressor of the carbon dioxide cascade system, reduce initial investment, reduce running pressure of the power grid and the unit and save running cost.

Disclosure of Invention

The utility model aims to solve the problems of large load fluctuation, unstable unit operation, low energy utilization rate, high operation cost and the like in a refrigerating system, and provides a carbon dioxide cascade refrigerating system with a cold accumulation device.

In order to achieve the above purpose, the present utility model provides the following technical solutions:

a carbon dioxide cascade refrigeration system with a cold accumulation device comprises a carbon dioxide low-temperature circulation system, a Freon high-temperature circulation system and a cold accumulation system;

the carbon dioxide low-temperature circulation system comprises a carbon dioxide compressor, an auxiliary condenser, a condensation evaporator, a carbon dioxide liquid storage device, a first electronic expansion valve, a carbon dioxide air cooler and a carbon dioxide heat regenerator, wherein the exhaust end of the carbon dioxide compressor is communicated with the input end of the carbon dioxide air cooler through a first working medium pipeline of the auxiliary condenser, the condensation side of the condensation evaporator, the carbon dioxide liquid storage device, a second working medium pipeline of the carbon dioxide heat regenerator, a filter and the first electronic expansion valve in sequence, and the output end of the carbon dioxide air cooler is communicated with the air suction end of the carbon dioxide compressor through a first working medium pipeline of the carbon dioxide heat regenerator to form a carbon dioxide circulation loop;

the Freon high-temperature circulation system comprises a Freon compressor, an evaporative condenser, a Freon liquid reservoir, a subcooler, a third electronic expansion valve and a condensing evaporator, wherein the exhaust end of the Freon compressor is communicated with the input end of the evaporating side of the condensing evaporator through a first working medium pipeline of the evaporative condenser, the Freon liquid reservoir and the subcooler in sequence, and the output end of the evaporating side of the condensing evaporator is communicated with the air suction end of the Freon compressor to form a Freon circulation loop;

the cold accumulation system comprises a Freon compressor, an evaporative condenser, a Freon reservoir, a subcooler, a second electronic expansion valve and a cold accumulation device, wherein a cold source of the cold accumulation system is a Freon refrigerating unit, an exhaust end of the Freon compressor is communicated with a first working medium pipeline of the subcooler through the evaporative condenser and the Freon reservoir in sequence, the first working medium pipeline of the subcooler is communicated with a cold accumulation coil inlet of the cold accumulation device through the second electronic expansion valve, and a cold accumulation coil outlet of the cold accumulation device is communicated with the Freon compressor to form a circulating loop of the cold accumulation system;

the water outlet of the cold accumulation device is divided into three branches through a pipeline, and the first branch is communicated with a water return pipe of the cold accumulation device to form a loop after heat exchange is carried out between the first branch and the high-temperature fresh-keeping warehouse/backwater through a heat exchanger by a first circulating water pump; the second branch is communicated with the cold accumulation device water return pipe through a second working medium pipeline of the auxiliary condenser by a second circulating water pump to form a loop; the third branch is connected with the cold accumulation device water return pipe through the second working medium pipeline of the subcooler by a third circulating water pump to form a loop.

The scheme comprises a carbon dioxide low-temperature circulation system, a Freon high-temperature circulation system and a cold accumulation system which are communicated through pipelines, wherein the cold accumulation system is provided with a cold source by a Freon unit, and the cold accumulation system can realize three purposes, namely, assisting carbon dioxide condensation, supercooling of the Freon system and providing cold energy for the tail end of a high-temperature fresh-keeping warehouse/air conditioner; the cold accumulation system and the overlapping system are matched with each other, so that the running cost pressure caused by large load fluctuation, large load difference in winter and summer, peak-valley electricity price and the like can be solved.

As a preferable scheme of the utility model, a first electromagnetic valve is arranged between the first working medium pipeline of the subcooler and the cold accumulation device, and a second electromagnetic valve is arranged between the first working medium pipeline of the subcooler and the condensing evaporator; the cold accumulation device is characterized in that a first electric regulating valve is arranged between the cold accumulation device and the first circulating water pump, a second electric regulating valve is arranged between the cold accumulation device and the second circulating water pump, and a third electric regulating valve is arranged between the cold accumulation device and the third circulating water pump. The electromagnetic valve and the electric regulating valve of the scheme are convenient to realize automatic switching under different working conditions, the first electric regulating valve, the second electric regulating valve and the third electric regulating valve can realize 0-100% opening regulation, and the common opening is controlled between 30% and 85%, so that automatic control can be realized.

As the preferable scheme of the utility model, the utility model further comprises an overhaul valve group, wherein a first overhaul valve is arranged between the second working medium pipeline of the carbon dioxide heat regenerator and the filter, and a second overhaul valve is arranged between the air cooler and the first working medium pipeline of the carbon dioxide heat regenerator. The maintenance valve of this scheme is convenient cuts off the pipeline when overhauling.

As a preferable scheme of the utility model, the cold accumulation device is provided with a visual tube, and an electronic ice storage amount sensor and a temperature sensor are arranged in the cold accumulation device. The visual tube of the scheme is convenient for checking the water level in the cold accumulation device (the water storage container with the coil pipe) on site; the electronic ice storage quantity sensor and the temperature sensor are convenient for automatically observing and recording the ice quantity and the temperature in the cold accumulation device, and the electronic ice storage quantity sensor has two output signals, one low water level alarm and one high water level ice making end.

As a preferable scheme of the utility model, the Freon high-temperature circulating system adopts an environment-friendly refrigerant. The Freon high-temperature circulating system adopts environment-friendly refrigerants such as refrigerant R32, refrigerant R290, refrigerant R436C, refrigerant R507A and the like.

As the preferable scheme of the utility model, the cold storage device comprises a single cold storage working condition connecting structure, a single cold supply working condition connecting structure of the overlapping system, and a combined cold supply working condition connecting structure of the overlapping system and the cold storage device;

the independent cold accumulation working condition connection structure is as follows: closing a first electric regulating valve, a second electric regulating valve and a third electric regulating valve, closing a second electromagnetic valve and a third electronic expansion valve, fully filling water in the cold accumulation device, starting the Freon compressor, sequentially compressing a fluorine refrigerant by the Freon compressor, condensing the fluorine refrigerant by the evaporative condenser and throttling the second electronic expansion valve, and then entering a coil pipe in the cold accumulation device to exchange heat with water in the cold accumulation device to make the water into ice;

the independent cooling working condition connection structure of the overlapping system is as follows: the Freon compressor and the second electromagnetic valve are started, the carbon dioxide compressor and the first electronic expansion valve are started, the Freon high-temperature circulating system exchanges heat with the carbon dioxide low-temperature circulating system through the condensing evaporator, and then the carbon dioxide refrigerant flows through the carbon dioxide air cooler to release cold energy;

the joint cold supply working condition connection structure of the overlapping system and the cold accumulation device is as follows: opening the Freon compressor, the first electromagnetic valve and the second electromagnetic valve, opening the carbon dioxide compressor and the first electronic expansion valve, wherein one path of the Freon refrigerating unit enters the cold accumulation device for cold accumulation through the first electromagnetic valve and the second electronic expansion valve, and the other path of the Freon refrigerating unit enters the condensing evaporator for heat exchange with high-temperature carbon dioxide refrigerant through the second electromagnetic valve and the third electronic expansion valve; the first electric regulating valve, the second electric regulating valve and the third electric regulating valve are opened, the first circulating water pump, the second circulating water pump and the third circulating water pump are started, the water outlet of the cold accumulation device is connected with three circulating loops, and one path of the cold accumulation device enters the heat exchanger through the first electric regulating valve and the first circulating water pump to exchange heat with circulating working media at the side of the high-temperature fresh-keeping warehouse and returns to the cold accumulation device; one path of the refrigerant enters the auxiliary condenser through the second electric regulating valve and the second circulating water pump to exchange heat with the carbon dioxide refrigerant and then returns to the cold accumulation device; one path of the refrigerant enters the subcooler through the third electric regulating valve and the third circulating water pump to exchange heat with the fluorine refrigerant and then returns to the cold accumulation device.

As a preferable scheme of the utility model, the cold accumulation system comprises three functional connection structures for assisting carbon dioxide condensation, supercooling of a fluorine system and cooling of the tail end of a high-temperature fresh-keeping warehouse/air conditioner;

auxiliary carbon dioxide condensation connection structure: opening a second electric regulating valve and a second circulating water pump, wherein cold water in the cold accumulation device enters a second working medium pipeline of the auxiliary condenser to exchange heat with carbon dioxide refrigerant in a first working medium pipeline of the auxiliary condenser after passing through the second electric regulating valve and the second circulating water pump; the connecting structure can reduce the temperature and pressure of the carbon dioxide refrigerant, reduce the running time of the fluorine compressor, reduce the start and stop times of the carbon dioxide compressor and the Freon compressor caused by matching, and enable the system to be more stable;

supercooling connection structure of fluorine system: a third electric regulating valve and a third circulating water pump are opened, and cold water in the cold accumulation device enters a second working medium pipeline of the subcooler to exchange heat with fluorine refrigerant in a first working medium pipeline of the subcooler after passing through the third electric regulating valve and the third circulating water pump; the connection structure can increase the supercooling degree of the Freon refrigerating system, reduce flash gas in a liquid tube of the Freon refrigerating agent, improve the refrigerating efficiency, generally increase 1K supercooling energy saving by 1%,10K supercooling energy saving by 13%, and simultaneously reduce the start and stop times of the Freon compressor due to the existence of a cold storage coil in the cold storage device;

terminal cold supply connection structure of high temperature fresh-keeping storehouse/air conditioner: opening a first electric regulating valve and a first circulating water pump, wherein cold water in the cold accumulation device enters the heat exchanger to provide cold energy for a circulating working medium at the other side; compared with a conventional air conditioning system, the cold accumulation scheme can reduce the initial investment cost of equipment, can also reduce the running time of an air conditioning unit, and particularly reduces the running time of the air conditioning unit in the electricity price peak time period.

The cold accumulation device provided by the scheme can pass through the auxiliary condenser to assist in condensing carbon dioxide, carbon dioxide exhaust preferentially passes through the auxiliary condenser, and the circulation exists to slow down the rising of the pressure of the carbon dioxide, so that the cascade system has a wider matching interval, the start and stop times of a carbon dioxide compressor are reduced, and the system is more stable in operation; when a conventional cascade system operates, if the suction pressure of the fluorine system is low, the controller can actively unload the fluorine system, the cold accumulation device in the scheme supercools the Freon refrigerant through the supercooler, the suction pressure rises, the refrigeration system continuously operates, a time margin is provided for the cooperation of the carbon dioxide refrigeration system, the flash gas generated in the throttling process of the system can be reduced, and the refrigeration efficiency of the fluorine system is improved; the scheme CO ₂ The low-temperature circulation system can provide cold energy for the quick-freezing warehouse and the cold storage warehouse, and the cold storage device can provide a stable cold energy for the high-temperature fresh-keeping warehouse, such as a banana warehouse; in addition, the cold accumulation device can also supply cold to the tail end of the air conditioner in summer.

Compared with the prior art, the utility model has the beneficial effects that: the problems of unstable unit operation and high operation pressure caused by large load fluctuation and large load difference in winter and summer can be solved; peak clipping and valley filling are carried out on the system, surplus cold sources are stored when the load is low, the cold storage device provides the cold sources when the load is high, the running pressure of equipment is reduced, the running stability of a unit and the utilization rate of energy sources are improved, and the initial investment is reduced; when the electricity price is at the peak value, the cold accumulation device outputs cold energy to precool carbon dioxide and supercool a fluorine system, so as to provide cold sources for an air conditioner and a fresh-keeping warehouse and reduce the operation of a refrigerating unit; when the electricity price is in the valley value, the refrigerating unit continues to operate, and the cold accumulation device stores redundant cold of the unit, so that the operation cost of the system is reduced; compared with the traditional fluorine refrigerating system, the efficiency is improved by 10-30%, the Freon filling amount is reduced by more than 90%, and the carbon emission is directly reduced by more than 95%, so that the system is environment-friendly, safe and efficient.

Drawings

Fig. 1 is a schematic structural view of the present utility model.

In the figure: 1. carbon dioxide compressor 2, auxiliary condenser 3, condensing evaporator

4. Carbon dioxide reservoir 5, first service valve 6, filter

7. First electronic expansion valve 8, carbon dioxide air cooler 9 and second maintenance valve

10. Carbon dioxide regenerator 11, freon compressor 12, evaporative condenser 13 freon reservoir 14, subcooler 15, first solenoid valve

16. A second electronic expansion valve 17, a cold accumulation device 18, a first electric regulating valve 19, a second electric regulating valve 20 and a third electric regulating valve

21. Third circulating water pump of first circulating water pump 22, second circulating water pump 23

24. A second solenoid valve 25, a third electronic expansion valve 26, and a heat exchanger.

Detailed Description

In order that the utility model may be readily understood, several embodiments of the utility model will be described more fully hereinafter with reference to the accompanying drawings, in which, however, the utility model may be embodied in many different forms and is not limited to the embodiments described herein, but instead is provided for the purpose of providing a more thorough and complete disclosure of the utility model.

It will be understood that when an element is referred to as being "mounted" on another element, it can be directly on the other element or intervening elements may also be present, and when an element is referred to as being "connected" to the other element, it may be directly connected to the other element or intervening elements may also be present, the terms "vertical", "horizontal", "left", "right" and the like are used herein for the purpose of illustration only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs, and the terms used herein in this description of the utility model are for the purpose of describing particular embodiments only and are not intended to be limiting of the utility model, with the term "and/or" as used herein including any and all combinations of one or more of the associated listed items.

Referring to fig. 1, the present utility model provides a technical solution:

a carbon dioxide cascade refrigeration system with a cold accumulation device comprises a carbon dioxide low-temperature circulation system, a Freon high-temperature circulation system and a cold accumulation system;

the carbon dioxide low-temperature circulation system comprises a carbon dioxide compressor 1, an auxiliary condenser 2, a condensation evaporator 3, a carbon dioxide liquid storage device 4, a first electronic expansion valve 7, a carbon dioxide air cooler 8 and a carbon dioxide heat regenerator 10, wherein the exhaust end of the carbon dioxide compressor 1 is communicated with the input end of the carbon dioxide air cooler 8 through a first working medium pipeline of the auxiliary condenser 2, the condensation side of the condensation evaporator 3, the carbon dioxide liquid storage device 4, a second working medium pipeline of the carbon dioxide heat regenerator 10, a filter 6 and the first electronic expansion valve 7 in sequence, and the output end of the carbon dioxide air cooler 8 is communicated with the air suction end of the carbon dioxide compressor 1 through the first working medium pipeline of the carbon dioxide heat regenerator 10 to form a carbon dioxide circulation loop;

the Freon high-temperature circulation system comprises a Freon compressor 11, an evaporative condenser 12, a Freon reservoir 13, a subcooler 14 and a third electronic expansion valve 25, wherein the exhaust end of the Freon compressor 11 is communicated with the input end of the evaporation side of the condensing evaporator 3 through a first working medium pipeline of the evaporative condenser 12, the Freon reservoir 13 and the subcooler 14 and the third electronic expansion valve 25 in sequence, and the output end of the evaporation side of the condensing evaporator 3 is communicated with the air suction end of the Freon compressor 11 to form a Freon circulation loop;

the cold accumulation system comprises a Freon compressor 11, an evaporative condenser 12, a Freon reservoir 13, a subcooler 14, a second electronic expansion valve 16 and a cold accumulation device 17, wherein a cold source of the cold accumulation system is a Freon refrigerating unit, an exhaust end of the Freon compressor 11 is communicated with a first working medium pipeline of the subcooler 14 through the evaporative condenser 12 and the Freon reservoir 13 in sequence, the first working medium pipeline of the subcooler 14 is communicated with a cold accumulation coil inlet of the cold accumulation device 17 through the second electronic expansion valve 16, and a cold accumulation coil outlet of the cold accumulation device is communicated with the Freon compressor 11 to form a cold accumulation system circulation loop;

the water outlet of the cold accumulation device 17 is divided into three branches through a pipeline, and the first branch is communicated with a return water pipe of the cold accumulation device 17 to form a loop after heat exchange is carried out between the first circulating water pump 21 and the return water of the air conditioner at the tail end of the air conditioner through the heat exchanger 26; the second branch is communicated with a water return pipe of the cold accumulation device 17 to form a loop after passing through a second working medium pipeline of the auxiliary condenser 2 through a second circulating water pump 22; the third branch is communicated with a water return pipe of the cold accumulation device 17 to form a loop after passing through a second working medium pipeline of the cooler 14 through a third circulating water pump 23.

A first electromagnetic valve 15 is arranged between the first working medium pipeline of the subcooler 14 and the cold accumulation device 17, and a second electromagnetic valve 24 is arranged between the first working medium pipeline of the subcooler 14 and the condensing evaporator 3; a first electric regulating valve 18 is arranged between the cold accumulation device 17 and the first circulating water pump 21, a second electric regulating valve 19 is arranged between the cold accumulation device 17 and the second circulating water pump 22, and a third electric regulating valve 20 is arranged between the cold accumulation device 17 and the third circulating water pump 23.

The device also comprises an overhaul valve group, wherein a first overhaul valve 5 is arranged between a second working medium pipeline of the carbon dioxide heat regenerator 10 and the filter 6, and a second overhaul valve 9 is arranged between the air cooler 8 and a first working medium pipeline of the carbon dioxide heat regenerator 10.

The cold accumulation device 17 is provided with a visible tube; an electronic ice storage amount sensor and a temperature sensor are arranged in the cold accumulation device.

The Freon high-temperature circulating system adopts an environment-friendly refrigerant.

The working process of the utility model comprises the following steps: as shown in fig. 1, the three working conditions are included, and the connecting structure under the three working conditions comprises a single cold storage working condition connecting structure, a single cold supply working condition connecting structure of the overlapping system, and a combined cold supply working condition connecting structure of the overlapping system and the cold storage device;

the independent cold accumulation working condition connection structure is as follows: closing the first electric regulating valve 18, the second electric regulating valve 19 and the third electric regulating valve 20, closing the second electromagnetic valve 24 and the third electronic expansion valve 25, fully filling the cold accumulation device 17 with water, starting the Freon compressor 11, sequentially compressing the Freon compressor 11, condensing the Freon refrigerant by the evaporative condenser 12 and throttling the Freon refrigerant by the second electronic expansion valve 16, and then entering a coil in the cold accumulation device 17 to exchange heat with water in the cold accumulation device 17 to make the water into ice;

the independent cold supply working condition connection structure of the overlapping system is as follows: starting a Freon compressor 11 and a second electromagnetic valve 24, starting a carbon dioxide compressor 1 and a first electronic expansion valve 7, exchanging heat between a Freon high-temperature circulation system and a carbon dioxide low-temperature circulation system through a condensation evaporator 3, and then enabling a carbon dioxide refrigerant to flow through a carbon dioxide air cooler 8 to release cold energy;

the joint cold supply working condition connection structure of the cascade system and the cold accumulation device is as follows: starting a Freon compressor 11, a first electromagnetic valve 15 and a second electromagnetic valve 24, starting a carbon dioxide compressor 1 and a first electronic expansion valve 7, wherein one path of the Freon refrigerating unit enters a cold accumulation device 17 for cold accumulation through the first electromagnetic valve 15 and the second electronic expansion valve 16, and the other path of the Freon refrigerating unit enters a condensing evaporator 3 for heat exchange with high-temperature carbon dioxide refrigerant through the second electromagnetic valve 24 and a third electronic expansion valve 25; the first electric regulating valve 18, the second electric regulating valve 19 and the third electric regulating valve 20 are opened, the first circulating water pump 21, the second circulating water pump 22 and the third circulating water pump 23 are started, the water outlet of the cold accumulation device 17 is connected with three circulating loops, and one path of the water enters the heat exchanger 26 through the first electric regulating valve 18 and the first circulating water pump 21 to exchange heat with the circulating working medium at the side of the high-temperature fresh-keeping warehouse and then returns to the cold accumulation device 17; one path enters the auxiliary condenser 2 through the second electric regulating valve 19 and the second circulating water pump 22 to exchange heat with the carbon dioxide refrigerant and then returns to the cold accumulation device 17; one path of the refrigerant enters the subcooler 14 through the third electric regulating valve 20 and the third circulating water pump 23 to exchange heat with the fluorine refrigerant and then returns to the cold accumulation device.

The cold accumulation system comprises three functional connection structures for assisting carbon dioxide condensation, supercooling of a fluorine system and cold supply at the tail end of a high-temperature fresh-keeping warehouse/air conditioner;

auxiliary carbon dioxide condensation connection structure: the second electric regulating valve 19 and the second circulating water pump 22 are opened, and cold water in the cold accumulation device 17 enters a second working medium pipeline of the auxiliary condenser 2 through the second electric regulating valve 19 and the second circulating water pump 22 to exchange heat with carbon dioxide refrigerant in a first working medium pipeline of the auxiliary condenser 2;

supercooling connection structure of fluorine system: the third electric regulating valve 20 and the third circulating water pump 23 are opened, and cold water in the cold accumulation device 17 enters the second working medium pipeline of the subcooler 14 through the third electric regulating valve 20 and the third circulating water pump 23 to exchange heat with fluorine refrigerant in the first working medium pipeline of the subcooler 14;

terminal cold supply connection structure of high temperature fresh-keeping storehouse/air conditioner: the first electric regulating valve 18 and the first circulating water pump 21 are opened, and cold water in the cold accumulation device 17 enters the heat exchanger 26 to provide cold energy for the circulating working medium on the other side.

Although embodiments of the present utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the utility model, the scope of which is defined in the appended claims and their equivalents.

Claims (7)

1. A carbon dioxide cascade refrigeration system with cold accumulation device, characterized in that: comprises a carbon dioxide low-temperature circulation system, a Freon high-temperature circulation system and a cold accumulation system;

the carbon dioxide low-temperature circulation system comprises a carbon dioxide compressor (1), an auxiliary condenser (2), a condensation evaporator (3), a carbon dioxide liquid storage device (4), a first electronic expansion valve (7), a carbon dioxide air cooler (8) and a carbon dioxide heat regenerator (10), wherein the exhaust end of the carbon dioxide compressor (1) sequentially passes through a first working medium pipeline of the auxiliary condenser (2), the condensation side of the condensation evaporator (3), a second working medium pipeline of the carbon dioxide liquid storage device (4), the carbon dioxide heat regenerator (10), a filter (6) and the first electronic expansion valve (7) to be communicated with the input end of the carbon dioxide air cooler (8), and the output end of the carbon dioxide air cooler (8) is communicated with the air suction end of the carbon dioxide compressor (1) through the first working medium pipeline of the carbon dioxide heat regenerator (10) to form a carbon dioxide circulation loop;

the Freon high-temperature circulation system comprises a Freon compressor (11), an evaporative condenser (12), a Freon liquid reservoir (13), a subcooler (14), a third electronic expansion valve (25) and a condensing evaporator (3), wherein the exhaust end of the Freon compressor (11) sequentially passes through a first working medium pipeline of the evaporative condenser (12), the Freon liquid reservoir (13) and the subcooler (14), the third electronic expansion valve (25) is communicated with the input end of the evaporating side of the condensing evaporator (3), and the output end of the evaporating side of the condensing evaporator (3) is communicated with the air suction end of the Freon compressor (11) to form a Freon circulation loop;

the cold accumulation system comprises a Freon compressor (11), an evaporative condenser (12), a Freon liquid reservoir (13), a subcooler (14) and a second electronic expansion valve (16) and a cold accumulation device (17), wherein a cold source of the cold accumulation system is a Freon refrigerating unit, an exhaust end of the Freon compressor (11) is sequentially communicated with a first working medium pipeline of the subcooler (14) through the evaporative condenser (12) and the Freon liquid reservoir (13), the first working medium pipeline of the subcooler (14) is communicated with a cold accumulation coil inlet of the cold accumulation device (17) through a second electronic expansion valve (16), and a cold accumulation coil outlet of the cold accumulation device is communicated with the Freon compressor (11) to form a circulating loop of the cold accumulation system;

the water outlet of the cold accumulation device (17) is divided into three branches through a pipeline, and the first branch is communicated with a water return pipe of the cold accumulation device (17) to form a loop after heat exchange is carried out between the first branch and the high-temperature fresh-keeping warehouse/backwater through a heat exchanger (26) by a first circulating water pump (21); the second branch is communicated with a water return pipe of the cold accumulation device (17) to form a loop after passing through a second working medium pipeline of the auxiliary condenser (2) through a second circulating water pump (22); the third branch is connected with the water return pipe of the cold accumulation device (17) to form a loop after passing through the second working medium pipeline of the subcooler (14) through a third circulating water pump (23).

2. A carbon dioxide cascade refrigeration system with a cold storage device as recited in claim 1, wherein: a first electromagnetic valve (15) is arranged between the first working medium pipeline of the subcooler (14) and the cold accumulation device (17), and a second electromagnetic valve (24) is arranged between the first working medium pipeline of the subcooler (14) and the condensing evaporator (3); a first electric regulating valve (18) is arranged between the cold accumulation device (17) and the first circulating water pump (21), a second electric regulating valve (19) is arranged between the cold accumulation device (17) and the second circulating water pump (22), and a third electric regulating valve (20) is arranged between the cold accumulation device (17) and the third circulating water pump (23).

3. A carbon dioxide cascade refrigeration system with a cold storage device as recited in claim 1, wherein: the device also comprises an overhaul valve group, wherein a first overhaul valve (5) is arranged between a second working medium pipeline of the carbon dioxide heat regenerator (10) and the filter (6), and a second overhaul valve (9) is arranged between the air cooler (8) and the first working medium pipeline of the carbon dioxide heat regenerator (10).

4. A carbon dioxide cascade refrigeration system with a cold storage device as recited in claim 1, wherein: the cold accumulation device (17) is provided with a visual tube, and an electronic ice storage amount sensor and a temperature sensor are arranged in the cold accumulation device.

5. A carbon dioxide cascade refrigeration system with a cold storage device as recited in claim 1, wherein: the Freon high-temperature circulating system adopts an environment-friendly refrigerant.

6. A carbon dioxide cascade refrigeration system with a cold storage device as recited in claim 1, wherein: the device comprises a single cold storage working condition connecting structure, a single cold supply working condition connecting structure of the overlapping system, and a combined cold supply working condition connecting structure of the overlapping system and the cold storage device;

the independent cold accumulation working condition connection structure is as follows: closing a first electric regulating valve (18), a second electric regulating valve (19) and a third electric regulating valve (20), closing a second electromagnetic valve (24) and a third electronic expansion valve (25), fully storing water in the cold storage device (17), starting the Freon compressor (11), compressing a fluorine refrigerant sequentially through the Freon compressor (11), condensing the evaporation type condenser (12) and throttling the second electronic expansion valve (16), and then entering a coil pipe in the cold storage device (17) to exchange heat with the water in the cold storage device (17) to make the water into ice;

the independent cooling working condition connection structure of the overlapping system is as follows: starting the Freon compressor (11) and the second electromagnetic valve (24), starting the carbon dioxide compressor (1) and the first electronic expansion valve (7), enabling the Freon high-temperature circulation system to exchange heat with the carbon dioxide low-temperature circulation system through the condensation evaporator (3), and enabling a carbon dioxide refrigerant to flow through the carbon dioxide air cooler (8) to release cold energy;

the joint cold supply working condition connection structure of the overlapping system and the cold accumulation device is as follows: opening the Freon compressor (11), a first electromagnetic valve (15) and a second electromagnetic valve (24), opening the carbon dioxide compressor (1) and a first electronic expansion valve (7), enabling one path of the Freon refrigerating unit to enter the cold accumulation device (17) for cold accumulation through the first electromagnetic valve (15) and the second electronic expansion valve (16), and enabling the other path of the Freon refrigerating unit to enter the condensing evaporator (3) for heat exchange with high-temperature carbon dioxide refrigerant through the second electromagnetic valve (24) and a third electronic expansion valve (25); opening the first electric regulating valve (18), the second electric regulating valve (19) and the third electric regulating valve (20), starting the first circulating water pump (21), the second circulating water pump (22) and the third circulating water pump (23), wherein the water outlet of the cold accumulation device (17) is connected with three circulating loops, and one path enters the heat exchanger (26) through the first electric regulating valve (18) and the first circulating water pump (21) to exchange heat with circulating working media at the side of the high-temperature fresh-keeping warehouse and returns to the cold accumulation device (17); one path enters the auxiliary condenser (2) through the second electric regulating valve (19) and the second circulating water pump (22) to exchange heat with the carbon dioxide refrigerant and then returns to the cold accumulation device (17); one path enters the subcooler (14) through the third electric regulating valve (20) and the third circulating water pump (23) to exchange heat with the fluorine refrigerant and then returns to the cold accumulation device.

7. A carbon dioxide cascade refrigeration system with a cold storage device as recited in claim 1, wherein: the cold accumulation system comprises three functional connection structures for assisting carbon dioxide condensation, supercooling of a fluorine system and cold supply at the tail end of a high-temperature fresh-keeping warehouse/air conditioner;

auxiliary carbon dioxide condensation connection structure: a second electric regulating valve (19) and a second circulating water pump (22) are opened, and cold water in the cold accumulation device (17) enters a second working medium pipeline of the auxiliary condenser (2) through the second electric regulating valve (19) and the second circulating water pump (22) to exchange heat with carbon dioxide refrigerant in a first working medium pipeline of the auxiliary condenser (2);

supercooling connection structure of fluorine system: a third electric regulating valve (20) and a third circulating water pump (23) are opened, and cold water in the cold accumulation device (17) enters a second working medium pipeline of the subcooler (14) through the third electric regulating valve (20) and the third circulating water pump (23) to exchange heat with fluorine refrigerant in a first working medium pipeline of the subcooler (14);

terminal cold supply connection structure of high temperature fresh-keeping storehouse/air conditioner: and opening a first electric regulating valve (18) and a first circulating water pump (21), wherein cold water in the cold accumulation device (17) enters the heat exchanger (26) to provide cold energy for the circulating working medium at the other side.