Heat pump driven device and method for preparing ice slurry in vacuum based on absorption refrigeration cycle

Abstract

The invention discloses a heat pump driven device and method for preparing ice slurry in vacuum based on absorption refrigeration cycle, vapor in an evaporation freezing chamber is absorbed by a concentrated solution in an absorber, so that a low-pressure environment is formed in the evaporation freezing chamber, water in the evaporation freezing chamber evaporates and absorbs heat of the water to be cooled, and the ice slurry is prepared. Ice slurry is formed on the ice forming device, is separated by the ice-water separator and is discharged by the ice discharging valve; a regeneration heat source is provided for a generator regeneration concentrated solution through a heat pump condenser, and a cold source is provided for an absorber and an ice-making water source supplemented into an evaporation freezing chamber through a heat pump evaporator; a compressor of the heat pump is driven by redundant off-peak electricity of a power grid or green electricity generated by renewable energy sources. The advantages of a vacuum method and a supercooling method are combined, meanwhile, the problems that the vacuum degree is difficult to maintain and energy consumption is high in the vacuum method can be solved, the problem of ice blockage existing in a freezing method is solved, and a feasible comprehensive solution is provided for ice slurry preparation and green electricity consumption.

Description

Technical Field

[0001] The invention relates to a device and method for preparing ice slurry, and in particular to a device and method for preparing ice slurry in a vacuum state driven by a heat pump and based on an absorption refrigeration cycle. Background Art

[0002] Renewable energy generation is intermittent, random, and has poor dispatchability, while the power grid has the characteristics of insufficient electricity during peak hours and inexhaustible electricity during low hours. Ice storage, as a new type of energy storage technology, can convert green electricity generated by renewable energy or excess valley electricity during the low hours of the power grid into ice for storage, and release the stored cold during peak hours to meet the cooling needs of the user side, achieving the purpose of "peak shaving and valley filling", thereby effectively utilizing renewable energy and balancing the load of the power grid. Ice slurry has good fluidity and good thermal properties. It is an important storage form of ice storage. It is of great significance to develop efficient ice slurry preparation methods and devices. Common ice slurry preparation methods include vacuum method and supercooling method. The vacuum method has problems such as difficulty in maintaining vacuum and difficulty in extracting ice, and the supercooling method has ice blockage problems. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a device and method for preparing ice slurry by vacuum driven by a heat pump based on an absorption refrigeration cycle, which can maintain the advantages of the traditional vacuum method and the supercooling method and solve the problems of difficulty in maintaining vacuum and ice blockage.

[0004] Technical solution: The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle of the present invention comprises a heat pump circulation loop, a solution circulation loop, a hot water loop, a chilled water loop and a vacuum ice making module;

[0005] The heat pump circulation loop includes a heat pump evaporator, a compressor, a heat pump condenser and a first throttle valve, the solution circulation loop includes an absorber, a solution pump, a second throttle valve and a generator, the vacuum ice-making module includes an evaporative freezing chamber, an ice-forming device and an ice-water separator are arranged from top to bottom inside the evaporative freezing chamber, and an ice-discharging valve connected to the outside, as well as a vacuum valve and a vacuum pump connected to the outside are respectively arranged on the evaporative freezing chamber, wherein the ice-discharging valve is at a position corresponding to the ice-water separator;

[0006] The absorber is used to continuously absorb water vapor in the evaporative freezing chamber through the concentrated solution therein, maintain the water vapor pressure in the evaporative freezing chamber below the saturated vapor pressure of water corresponding to 0°C, and the concentrated solution that absorbs the water vapor becomes a dilute solution; the heat pump condenser provides a regeneration heat source for the generator to heat the dilute solution and concentrate it into a concentrated solution through the hot water circuit, and the concentrated solution after regeneration returns to the absorber; the heat pump evaporator provides a cold source for the absorber and the ice-making water source replenished in the evaporative freezing chamber through the chilled water circuit; the ice-forming device is used to thaw and generate ice slurry when water evaporates and absorbs its own heat and the temperature drops below 0°C, the ice-water separator is used to separate the ice slurry, and the ice discharge valve is used to discharge the ice slurry; the vacuum valve and the vacuum pump are used to form a certain vacuum degree in the evaporative freezing chamber.

[0007] Furthermore, the compressor is driven by excess off-peak electricity from the power grid or green electricity generated by renewable energy.

[0008] The absorption refrigeration cycle is driven by a heat pump, and the heat pump condenser and heat pump evaporator are used to provide the heat source and cold source required for making ice slurry respectively. The green electricity generated by the valley electricity of the power grid or renewable energy is used to drive the heat pump, which can realize the "peak shaving and valley filling" of the power grid and realize the storage and consumption of green electricity. This provides a feasible comprehensive solution for ice slurry production and green electricity consumption. The absorption refrigeration device and heat pump device are both mature technologies, and only need to be modified and upgraded to realize the solution of the present invention, which is highly feasible.

[0009] Furthermore, the ice-making water source includes make-up water from a make-up water tank, which is connected to the evaporative freezer via a fourth throttle valve; the chilled water circuit includes a chilled water pump, a coil in a heat pump evaporator, a coil in an absorber, and a second heat exchanger, the second heat exchanger being used for heat exchange between the make-up water and the chilled water, and the amount of make-up water is controlled according to the water level in the evaporative freezer.

[0010] Furthermore, the ice-making water source also includes water vapor generated by the generator, the vacuum ice-making module also includes a condenser, and the chilled water circuit also includes a third heat exchanger; the condenser is used to convert the water vapor generated by the generator into condensed water, and the condensed water outlet of the condenser is connected to the evaporative freezing chamber through a third throttle valve, and the third heat exchanger is used for heat exchange between condensed water and chilled water.

[0011] Furthermore, the condenser provides a cold source through a cooling water loop, and the cooling water loop includes a cooling water pump, a cooling tower and a coil in the condenser.

[0012] Furthermore, a circulating water spray system is provided on the evaporative freezing chamber, and the circulating water spray system includes a spray water pump, the spray water pump inlet is connected to the outlet at the bottom of the evaporative freezing chamber, and the outlet is connected to the sprayer inside the evaporative freezing chamber, and the sprayer is located above the ice-forming device.

[0013] Furthermore, a filter is provided on the pipeline between the bottom outlet of the evaporative freezing chamber and the spray water pump.

[0014] Furthermore, the solution circulation loop also includes a first heat exchanger for heat exchange between the dilute solution and the concentrated solution between the absorber and the generator.

[0015] Furthermore, the hot water circuit includes a hot water pump, a coil in a heat pump condenser and a coil in a generator.

[0016] The method for preparing ice slurry by the device for preparing ice slurry by vacuum based on absorption refrigeration cycle driven by heat pump described in the present invention comprises: absorbing water vapor in evaporative freezing chamber by concentrated solution in absorber, so that low-pressure environment is formed in evaporative freezing chamber, water in evaporative freezing chamber evaporates and absorbs its own heat to cool down, and ice slurry is formed on ice-forming device; ice slurry falls on ice-water separator, when the ice slurry on the ice-water separator reaches a certain amount, ice-water separator separates ice slurry, opens ice discharge valve to discharge ice slurry; after ice slurry is discharged, closes ice discharge valve, opens vacuum valve, starts vacuum pump to maintain a certain vacuum degree in evaporative freezing chamber; then closes vacuum valve to complete an ice discharge process.

[0017] The principle of ice slurry preparation of the present invention is:

[0018] The concentrated solution in the absorber absorbs the water vapor in the evaporative freezing chamber, so that a low-pressure (vacuum) environment is formed in the evaporative freezing chamber. The water in the evaporative freezing chamber evaporates and absorbs its own heat to cool down, forming ice slurry on the ice-forming device.

[0019] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0020] The present invention is based on an absorption refrigeration cycle and combines the advantages of traditional vacuum methods and supercooling methods. The concentrated solution continuously absorbs water vapor in the absorber to form a low-pressure (vacuum) environment in the evaporative freezing chamber, thereby avoiding the problem of difficult maintenance of vacuum degree in conventional vacuum methods and reducing energy consumption. The water evaporates to absorb its own heat and partially freezes into ice slurry, thereby avoiding the ice blockage problem of conventional freezing methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a heat pump driven vacuum ice slurry production device based on an absorption refrigeration cycle provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings.

[0023] Attached Figure 1 The reference numerals in the figures are as follows:

[0024] 1. Heat pump evaporator; 2. Compressor; 3. Heat pump condenser; 4. First throttle valve; 5. Chilled water pump; 6. Absorber; 7. Solution pump; 8. Second throttle valve; 9. First heat exchanger; 10. Generator; 11. Hot water pump; 12. Condenser; 13. Third throttle valve; 14. Evaporative freezing chamber; 15. Spray water pump; 16. Cooling water pump; 17. Cooling tower; 18. Filter; 19. Ice-forming device; 20. Ice-water separator; 21. Second heat exchanger; 22. Third heat exchanger; 23. Vacuum valve; 24. Vacuum pump; 25. Ice discharge valve; 26. Fourth throttle valve; 27. Make-up water tank.

[0025] like Figure 1 As shown, an embodiment of the present invention provides a heat pump driven vacuum ice slurry production device based on an absorption refrigeration cycle, including a heat pump circulation loop, a solution circulation loop, a hot water loop, a chilled water loop, a cooling water loop and a vacuum ice making module.

[0026] The heat pump circulation loop includes a heat pump evaporator 1, a compressor 2, a heat pump condenser 3 and a first throttle valve 4, wherein the compressor 2 is driven by excess valley electricity of the power grid or green electricity generated by renewable energy, and the refrigerant is R134a or the like.

[0027] The solution circulation loop includes an absorber 6, a solution pump 7, a second throttle valve 8, a first heat exchanger 9 and a generator 10. The solution is an aqueous solution such as LiBr, LiCl, CaBr2, etc.

[0028] The hot water circuit includes a hot water pump 11 , a coil in the heat pump condenser 3 and a coil in the generator 10 .

[0029] The chilled water circuit includes a chilled water pump 5 , a coil in the heat pump evaporator 1 , a coil in the absorber 6 , a second heat exchanger 21 and a third heat exchanger 22 .

[0030] The vacuum ice making module includes a condenser 12, an evaporative freezing chamber 14, a water supply tank 27, and a circulating water spray system arranged on the evaporative freezing chamber 14. The condensed water outlet of the condenser 12 is connected to the top of the evaporative freezing chamber 14 through the third heat exchanger 22 and the third throttle valve 13 in sequence, and the water supply tank 27 is connected to the bottom of the evaporative freezing chamber 14 through the second heat exchanger 21 and the fourth throttle valve 26 in sequence. The circulating water spray system includes a spray water pump 15, the inlet of the spray water pump 15 is connected to the outlet at the bottom of the evaporative freezing chamber 14, and the outlet is connected to the sprayer inside the evaporative freezing chamber 14. A filter 18 is arranged on the pipeline between the outlet at the bottom of the evaporative freezing chamber 14 and the spray water pump 15. An ice forming device 19 and an ice-water separator 20 are arranged below the sprayer in sequence. An ice discharge valve 25 communicating with the outside is arranged at a position corresponding to the ice-water separator 20 on the evaporative freezing chamber 14, and a vacuum valve 23 and a vacuum pump 24 communicating with the outside are arranged at the top of the evaporative freezing chamber 14.

[0031] The evaporation freezing chamber 14 is connected to the absorber 6 through a pipeline, and the generator 10 is connected to the condenser 12 through a pipeline.

[0032] The cooling water circuit includes a cooling water pump 16 , a cooling tower 17 and the coils in the condenser 12 .

[0033] The embodiment of the present invention also provides a method for preparing ice slurry using the heat pump driven vacuum ice slurry preparation device based on absorption refrigeration cycle described in the embodiment of the present invention, which is specifically:

[0034] The concentrated solution in the absorber 6 continuously absorbs the water vapor in the evaporation freezing chamber 14, and maintains the water vapor pressure in the evaporation freezing chamber 14 below 611.66Pa (i.e., the saturated vapor pressure corresponding to water at 0°C). The water evaporates and absorbs its own heat to cool down. When the temperature drops below 0°C, it is thawed by the ice-forming device 19 to generate ice slurry, and the ice slurry falls on the ice-water separator 20. When the ice slurry on the ice-water separator 20 reaches a certain amount, the ice-water separator 20 separates the ice slurry, and opens the ice discharge valve 25 to discharge the ice slurry; after the ice slurry is discharged, the ice discharge valve 25 is closed, and then the vacuum valve 23 is opened, and the vacuum pump 24 is turned on to maintain a certain vacuum degree in the evaporation freezing chamber 14; then the vacuum valve 23 is closed to complete an ice discharge process.

[0035] The concentrated solution that has absorbed the water vapor becomes a dilute solution, and then is sent to the generator 10 through the solution pump 7 for heating and concentration to complete regeneration. The regeneration heat source is provided by the heat pump condenser 3 through the hot water circuit. The concentrated solution after regeneration returns to the absorber 6 through the second throttle valve 8, and after being cooled by the chilled water provided by the heat pump evaporator 1, the moisture absorption capacity is restored, and the water vapor in the evaporation freezing chamber 14 is continuously absorbed. The dilute solution and the concentrated solution between the absorber 6 and the generator 10 are heat exchanged by the first heat exchanger 9 to improve energy efficiency.

[0036] There are two sources of ice-making water for replenishing the evaporative freezing chamber 14, including replenishing water from the replenishing water tank 27 and water vapor generated by the generator 10. The water vapor generated in the generator 10 first passes through the condenser 12 to become condensed water, then passes through the third heat exchanger 22 to be cooled by the chilled water provided by the heat pump evaporator 1, and then is throttled by the third throttle valve 13 before being sent to the evaporative freezing chamber 14 to complete the refrigerant water cycle. The condenser 12 is provided with cooling water by the cooling tower 17. The replenishing water in the replenishing water tank 27 is cooled by the chilled water provided by the heat pump evaporator 1 through the second heat exchanger 21, and then is throttled by the fourth throttle valve 26 before being sent to the evaporative freezing chamber 14 to complete the replenishing water. The replenishing water amount is controlled according to the water level in the evaporative freezing chamber 14.

[0037] The circulating water spray system provided on the evaporative freezing chamber 14 can increase the evaporation rate of water vapor.

[0038] In the ice slurry preparation process of the present invention, the heat pump evaporator 1 provides the cold source required for water replenishment in the absorber 6 and the evaporative freezing chamber 14, and the heat pump condenser 3 provides the heat source required for the generator 10. The compressor 2 of the heat pump is driven by excess valley electricity of the power grid or green electricity generated by renewable energy, which can alleviate the power grid power consumption pressure, realize flexible regulation of the power grid and "peak shaving and valley filling", realize the storage and consumption of green electricity and convert it into cold capacity, and can be used in building air conditioning, refrigeration, food preservation and other fields.

Claims

1. A heat pump driven vacuum ice slurry production device based on absorption refrigeration cycle, characterized in that: It includes a heat pump circulation loop, a solution circulation loop, a hot water loop, a chilled water loop and a vacuum ice making module; The heat pump circulation loop comprises a heat pump evaporator (1), a compressor (2), a heat pump condenser (3) and a first throttle valve (4); the solution circulation loop comprises an absorber (6), a solution pump (7), a second throttle valve (8) and a generator (10); the vacuum ice-making module comprises an evaporative freezing chamber (14); an ice-forming device (19) and an ice-water separator (20) are arranged from top to bottom in the evaporative freezing chamber (14); an ice-discharging valve (25) communicating with the outside, and a vacuum valve (23) and a vacuum pump (24) communicating with the outside are respectively arranged on the evaporative freezing chamber (14); the ice-discharging valve (25) is located at a position corresponding to the ice-water separator (20); The absorber (6) is used to continuously absorb water vapor in the evaporation freezing chamber (14) through the concentrated solution therein, so as to maintain the water vapor pressure in the evaporation freezing chamber (14) below the saturated vapor pressure corresponding to water at 0°C, and the concentrated solution after absorbing the water vapor becomes a dilute solution; the heat pump condenser (3) provides a regeneration heat source for the generator (10) to heat and concentrate the dilute solution into a concentrated solution through the hot water circuit, and the concentrated solution after regeneration is returned to the absorber (6); the heat pump evaporator (1) provides a cold source for the absorber (6) and the ice-making water source replenished in the evaporation freezing chamber (14) through the chilled water circuit; the ice-forming device (19) is used to thaw and generate ice slurry when the water evaporates and absorbs its own heat and the temperature drops below 0°C; the ice-water separator (20) is used to separate the ice slurry, and the ice discharge valve (25) is used to discharge the ice slurry; the vacuum valve (23) and the vacuum pump (24) are used to form a certain vacuum degree in the evaporation freezing chamber (14).

2. The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle according to claim 1, characterized in that: The compressor (2) is driven by excess off-peak electricity from the power grid or green electricity generated by renewable energy.

3. The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle according to claim 1, characterized in that: The ice-making water source includes make-up water from a make-up water tank (27), and the make-up water tank (27) is connected to the evaporative freezing chamber (14) via a fourth throttle valve (26); the chilled water circuit includes a chilled water pump (5), a coil in a heat pump evaporator (1), a coil in an absorber (6), and a second heat exchanger (21), and the second heat exchanger (21) is used for heat exchange between the make-up water and the chilled water, and the amount of the make-up water is controlled according to the water level in the evaporative freezing chamber (14).

4. The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle according to claim 3, characterized in that: The ice-making water source also includes water vapor generated by the generator (10), the vacuum ice-making module also includes a condenser (12), and the chilled water circuit also includes a third heat exchanger (22); the condenser (12) is used to convert the water vapor generated by the generator (10) into condensed water, the condensed water outlet of the condenser (12) is connected to the evaporative freezing chamber (14) via a third throttle valve (13), and the third heat exchanger (22) is used to perform heat exchange between condensed water and chilled water.

5. The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle according to claim 4, characterized in that: The condenser (12) provides a cold source through a cooling water circuit, wherein the cooling water circuit includes a cooling water pump (16), a cooling tower (17) and a coil in the condenser (12).

6. The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle according to claim 1, characterized in that: A circulating water spray system is provided on the evaporative freezing chamber (14), the circulating water spray system comprising a spray water pump (15), the inlet of the spray water pump (15) is connected to the outlet at the bottom of the evaporative freezing chamber (14), and the outlet is connected to a sprayer inside the evaporative freezing chamber (14), and the sprayer is located above the ice forming device (19).

7. The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle according to claim 6, characterized in that: A filter (18) is provided on the pipeline between the bottom outlet of the evaporative freezing chamber (14) and the spray water pump (15).

8. The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle according to claim 1, characterized in that: The solution circulation loop further comprises a first heat exchanger (9) for heat exchange between the dilute solution and the concentrated solution between the absorber (6) and the generator (10).

9. The heat pump driven vacuum ice slurry making device based on absorption refrigeration cycle according to claim 1, characterized in that: The hot water circuit comprises a hot water pump (11), a coil in a heat pump condenser (3) and a coil in a generator (10).

10. A method for preparing ice slurry using a heat pump driven vacuum ice slurry preparation device based on an absorption refrigeration cycle according to any one of claims 1 to 9, characterized in that: include: The concentrated solution in the absorber (6) absorbs the water vapor in the evaporation freezing chamber (14), so that a low-pressure environment is formed in the evaporation freezing chamber (14). The water in the evaporation freezing chamber (14) evaporates and absorbs its own heat to cool down, forming ice slurry on the ice-forming device (19); the ice slurry falls on the ice-water separator (20); when the ice slurry on the ice-water separator (20) reaches a certain amount, the ice-water separator (20) separates the ice slurry, and opens the ice discharge valve (25) to discharge the ice slurry; after the ice slurry is discharged, the ice discharge valve (25) is closed, and then the vacuum valve (23) is opened, and the vacuum pump (24) is turned on to maintain a certain vacuum degree in the evaporation freezing chamber (14); then the vacuum valve (23) is closed to complete an ice discharge process.

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