An operation control method of an evaporative cooling and mechanical refrigeration combined refrigeration water chiller

Abstract

The application discloses an evaporative cooling and mechanical refrigeration combined refrigeration water chilling unit operation control method, which comprises the following steps: S1, setting an outdoor temperature detection instrument to monitor the outdoor temperature; S2, calculating the wet-bulb temperature according to the outdoor temperature; S3, controlling the valve of the unit according to the wet-bulb temperature and the water supply temperature by a control system; different combined schemes including a filler open type, a coil closed type and a coil+condenser closed type are adopted, the environmental temperature change is utilized, the best refrigeration mode and working mode are selected, and the energy consumption is maximally reduced; the application has the advantages that the energy consumption of the water chilling unit can be reduced, the energy efficiency is improved, the natural cold source is fully utilized, and the requirements of the double-carbon policy are met; and the application is suitable for various places, such as commercial buildings, industrial workshops and families, and has important significance for energy saving and emission reduction.

Description

Technical Field

[0001] This invention relates to the field of chiller technology, and in particular to an operation control method for a combined evaporative cooling and mechanical refrigeration chiller. Background Technology

[0002] A chiller is a device used for refrigeration and air conditioning, widely used in commercial buildings, industrial plants, and homes. It works by circulating refrigerant to absorb and expel heat from the room, thus achieving cooling and temperature control. With advancements in science and technology and engineering, chillers have gradually achieved improvements in automation, energy efficiency, and operational stability.

[0003] Currently, chiller units have achieved a series of technological breakthroughs and innovations. The widespread application of new-generation refrigerants has reduced negative environmental impacts. Secondly, in terms of energy efficiency, the design and control methods of chiller units are constantly being improved to enhance energy utilization. However, chiller units still have some limitations at this stage. Especially in terms of energy consumption, chiller units require a large amount of electricity during operation, resulting in high energy demands.

[0004] Against the backdrop of my country's dual-carbon policy, all industries are striving to reduce energy consumption and improve efficiency. For example, with increasingly stringent requirements from local governments for data centers, there is great potential for further energy conservation and efficiency improvements in chiller units. To reduce chiller unit energy consumption and make full use of natural cooling sources, there is an urgent need for an operation and control method for chiller units that combine evaporative cooling and mechanical refrigeration. Summary of the Invention

[0005] The purpose of this invention is to provide an operation control method for a combined evaporative cooling and mechanical refrigeration chiller unit, which can realize natural cold source cooling during the transition season and winter, make full use of natural cold source, and reduce unit energy consumption.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a method for operating and controlling a combined evaporative cooling and mechanical refrigeration chiller unit, comprising the following steps:

[0008] S1. Install a temperature detection instrument outdoors to monitor the outdoor temperature T. a ;

[0009] S2. Based on outdoor temperature T a Calculate the wet-bulb temperature T w ;

[0010] S3. The control system is based on the wet-bulb temperature T. w The valves of the unit are controlled in accordance with the water supply temperature t.

[0011] Preferably, in step S2, T w The method for calculating wet-bulb temperature is as follows:

[0012] T w = T a - ((T a - 14.55) / 2.5) * (1 + 0.00418 * RH * (1 - 0.000016 *P)) (1); Among them, T w T is the wet-bulb temperature. a Outdoor temperature, i.e., dry bulb temperature; RH is relative humidity; P is atmospheric pressure.

[0013] Preferably, in step S3, the unit is a packed open unit, a coil closed unit, or a coil + condenser closed unit.

[0014] Preferably, when using the packing open-type unit, during unit operation, the packing open-type unit water pump two and the packing open-type unit fan are turned on, and the upper spray nozzles of the packing open-type unit are opened for spraying. Air and water undergo sufficient heat and moisture exchange through the packing, and chilled water is produced by evaporative cooling. When t>T0, the evaporative cooling section is turned on, and the packing open-type unit water pump one, the packing open-type unit valve seven, and the packing open-type unit valve eight are turned on. The produced chilled water exchanges heat with the user terminal through a plate heat exchanger to achieve completely natural cooling. When t≤T0, the mechanical refrigeration section is turned on, and the packing open-type unit compressor and the packing open-type unit water pump one are turned on. Valves five and six of the packing open unit allow the produced chilled water to be fed into the condenser of the packing open unit to cool the high-temperature, high-pressure refrigerant. After passing through the packing open unit's throttling valve, the water then exchanges heat with the user's terminal via the heat exchanger, completing the cooling supply. In winter, when the system freezes, valve nine of the packing open unit is opened to open the lower spray nozzles for spraying, ensuring the unit's normal operation. When there is a need for heat, valves one, seven, and eight of the packing open unit's water pump are opened to deliver the hot water, after heat exchange in the condenser, to the user for waste heat utilization.

[0015] Preferably, the method for calculating the minimum outlet water temperature T0 is as follows:

[0016] T0 = ​​T w +2 (2).

[0017] Preferably, when the coil-type closed-loop unit is used, when t>T wWhen t ≤ T, the evaporative cooling section is activated, along with the water pump and fan of the closed-loop chiller unit. The spray nozzles of the closed-loop chiller unit are also turned on to spray the working fluid, utilizing indirect evaporative cooling to cool the working fluid within the coils. The water pump, valves 1, 2, 3, and 4 of the closed-loop chiller unit are then opened, allowing the cooled working fluid to be directly supplied to the user's terminal for cooling. w When the mechanical refrigeration section is turned on, the water pump, valve 1, valve 2, and compressor of the closed-loop unit are opened. Cold water is produced by evaporative cooling and then fed into the condenser of the closed-loop unit for cooling, reducing the energy consumption of the compressor. The low-temperature, low-pressure refrigerant after passing through the expansion valve of the closed-loop unit exchanges heat with the user terminal through the heat exchanger of the closed-loop unit.

[0018] Preferably, when using the coil + condenser closed-loop unit, during unit operation, the coil + condenser closed-loop unit fan, coil + condenser closed-loop unit spray nozzle, and coil + condenser closed-loop unit water pump two are turned on, and the user terminal working fluid is introduced into the coil + condenser closed-loop unit condenser. When t > T w When t ≤ T, the evaporative cooling section is activated, and the water pumps 1, 3, and 4 of the coil + condenser closed-loop unit are opened. Indirect evaporative cooling of the working fluid at the user's end is achieved solely through spraying from the coil + condenser closed-loop unit nozzles. w When the mechanical refrigeration section is activated, the compressor, water pump 1, and valve 2 of the coil + condenser closed-circuit unit are turned on. Evaporative cooling is used to cool the refrigerant in the coil of the coil + condenser closed-circuit unit, reducing the energy consumption of the compressor. Then, the heat exchanger of the coil + condenser closed-circuit unit exchanges heat with the working fluid at the user's terminal to complete the cooling supply.

[0019] The present invention achieves the following beneficial technical effects compared to the prior art:

[0020] 1. This invention provides a method for controlling the operation of a combined evaporative cooling and mechanical refrigeration chiller unit. It employs a packed-fill open-type unit. When t > T0, evaporative cooling provides "free" cooling via plate heat exchangers and user-side terminals. When t ≤ T0, evaporative cooling produces chilled water to cool the refrigerant in the condenser, reducing compressor energy consumption. It also features upper and lower spray nozzles; the lower nozzle is activated during winter freezing to ensure normal unit operation. Furthermore, heat recovery is included, allowing the waste heat from the condenser to be utilized and supplied to users when heat demand arises. This solution utilizes ambient temperature changes to select the optimal cooling method and operating mode to minimize energy consumption. Simultaneously, by adding an energy recovery device, waste heat is converted into reusable energy, improving overall energy efficiency.

[0021] 2. The present invention provides an operation control method for a combined evaporative cooling and mechanical refrigeration chiller unit, which adopts a coil-type closed-loop unit, and the working fluid is introduced into the coil. When t>T w Evaporative cooling is activated at certain times, utilizing indirect evaporative cooling for cooling. Furthermore, due to its closed-loop system, it is unaffected by external contamination and can be directly applied to end-user applications; when t≤T w When needed, mechanical refrigeration is activated to cool the working fluid at the user's end; at the same time, evaporative cooling is used to produce chilled water to cool the condenser and reduce compressor energy consumption.

[0022] 3. The present invention provides an operation control method for a combined evaporative cooling and mechanical refrigeration chiller unit, employing a coil + condenser closed-loop unit, where the working fluid at the user terminal is directly introduced into the condenser. When t > T w Only the evaporative cooling section is activated to cool the working fluid at the user's end; when t≤T w When the refrigerant is cooled, the mechanical refrigeration section is activated, and the refrigerant in the coil is cooled by evaporative cooling to reduce the energy consumption of the compressor. Then, the heat exchanger is used to exchange heat with the working fluid at the user's terminal to achieve cooling. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This invention provides a schematic diagram of the principle of an open-type packing chiller unit in a combined evaporative cooling and mechanical refrigeration chiller unit operation control method.

[0025] Figure 2A schematic diagram of the closed-loop coil unit in the operation control method of a combined evaporative cooling and mechanical refrigeration chiller unit provided by the present invention;

[0026] Figure 3 A schematic diagram of the principle of a closed-loop unit with coil and condenser in a combined evaporative cooling and mechanical refrigeration chiller operation control method provided by the present invention;

[0027] In the diagram: 1. Fan of the packing open unit, 2. Upper nozzle of the packing open unit, 3. Packing, 4. Lower nozzle of the packing open unit, 5. Condenser of the packing open unit, 6. Heat exchanger of the packing open unit, 7. User terminal, 8. Heat user, 9. Compressor of the packing open unit, 10. Water pump one of the packing open unit, 11. Plate heat exchanger, 12. Water pump two of the packing open unit, V1. Throttling valve of the packing open unit, V2. Valve one of the packing open unit, V3. Valve two of the packing open unit, V4. Valve three of the packing open unit, V5. Valve four of the packing open unit, V6. Valve five of the packing open unit, V7. Valve six of the packing open unit, V8. Valve seven of the packing open unit, V9. Valve eight of the packing open unit, V10. Valve nine of the packing open unit;

[0028] 13. Fan of closed-circuit fan unit; 14. Sprayer of closed-circuit fan unit; 15. Coil of closed-circuit fan unit; 16. Pump 1 of closed-circuit fan unit; 17. Condenser of closed-circuit fan unit; 18. Heat exchanger of closed-circuit fan unit; 19. Compressor of closed-circuit fan unit; 20. Pump 2 of closed-circuit fan unit; V11. Valve 1 of closed-circuit fan unit; V12. Valve 2 of closed-circuit fan unit; V13. Valve 3 of closed-circuit fan unit; V14. Valve 4 of closed-circuit fan unit; V15. Throttling valve of closed-circuit fan unit.

[0029] 21. Fan of closed-loop unit with coil + condenser; 22. Nozzle of closed-loop unit with coil + condenser; 23. Coil of closed-loop unit with coil + condenser; 24. Condenser of closed-loop unit with coil + condenser; 25. Compressor of closed-loop unit with coil + condenser; 26. Heat exchanger of closed-loop unit with coil + condenser; 27. Water pump one of closed-loop unit with coil + condenser; 28. Water pump two of closed-loop unit with coil + condenser; V16. Throttling valve of closed-loop unit with coil + condenser; V17. Valve one of closed-loop unit with coil + condenser; V18. Valve two of closed-loop unit with coil + condenser; V19. Valve three of closed-loop unit with coil + condenser. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The purpose of this invention is to provide a method for operating and controlling a combined evaporative cooling and mechanical refrigeration chiller unit to solve the problems existing in the prior art.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1:

[0034] This embodiment provides a method for operating and controlling a combined evaporative cooling and mechanical refrigeration chiller unit, including the following steps:

[0035] S1. Install a temperature detection instrument outdoors to monitor the outdoor temperature T. a ;

[0036] S2. Based on outdoor temperature T a Calculate the wet-bulb temperature T w ;

[0037] S3. The control system is based on the wet-bulb temperature T. w The valves of the unit are controlled in accordance with the water supply temperature t.

[0038] Specifically, in step S2, T w The method for calculating wet-bulb temperature is as follows:

[0039] T w = T a - ((T a - 14.55) / 2.5) * (1 + 0.00418 * RH * (1 - 0.000016 *P)) (1); Among them, T w T is the wet-bulb temperature. a Outdoor temperature, also known as dry-bulb temperature; RH is relative humidity; P is atmospheric pressure. All temperatures are in degrees Celsius, and pressure is in Pascals.

[0040] As one embodiment, the unit adopts a packed open-type unit, such as... Figure 1As shown, when the unit is running, the packing open unit water pump 2 12 and the packing open unit fan 1 are turned on, and the upper spray nozzle 2 of the packing open unit is turned on for spraying. Air and water undergo sufficient heat and moisture exchange through the packing 3, and chilled water is produced by evaporative cooling. When t>T0, the evaporative cooling section is turned on, and the packing open unit water pump 1 10, the packing open unit valve 7 V8, and the packing open unit valve 8 V9 are turned on. The produced chilled water exchanges heat with the user terminal through the plate heat exchanger 11 to achieve completely natural cooling. When t≤T0, the mechanical refrigeration section is turned on, and the packing open unit compressor 9, the packing open unit water pump 1 10, and the packing open unit valve 8 are turned on. Valves V6 and V7 of the packing open unit allow the produced chilled water to be fed into the condenser 5 of the packing open unit to cool the high-temperature, high-pressure refrigerant. After passing through the throttle valve V1, the water then exchanges heat with the user terminal 7 via the heat exchanger 6, completing the cooling supply. In winter, when the system freezes, valve V10 of the packing open unit is opened to open the lower spray nozzles 4 for spraying, ensuring normal operation of the unit. When there is a need for heat, the water pump 10, valve V8, and valve V9 of the packing open unit are opened to send the hot water, after heat exchange in the condenser 5, to the heat user 8 for waste heat utilization.

[0041] In this embodiment, when the working fluid at the user's end exchanges heat with the chilled water produced by the unit through the plate heat exchanger, there is a heat exchange temperature difference. To ensure the unit's outlet water temperature t, the temperature of the chilled water produced by the unit should take into account the heat exchange temperature difference. Based on experience, 2℃ is selected. The calculation method for the minimum outlet water temperature T0 is as follows:

[0042] T0 = ​​T w +2 (2).

[0043] Example 2:

[0044] This embodiment provides another method for operating and controlling a combined evaporative cooling and mechanical refrigeration chiller unit. The difference from Embodiment 1 is that it uses a closed-loop coil unit, such as... Figure 2 As shown, when t>T w When t ≤ T, the evaporative cooling section is activated, and the second water pump 20 and the fan 13 of the closed-loop unit are turned on. The spray nozzles 14 of the closed-loop unit are opened for spraying, using indirect evaporative cooling to cool the working fluid in the coil 15 of the closed-loop unit. The first water pump 16, valve 1 V11, valve 2 V12, valve 3 V13, and valve 4 V14 of the closed-loop unit are opened, and the cooled working fluid is directly sent to the user terminal 7 for cooling. wWhen the mechanical refrigeration section is activated, the water pump 16, valve 1 V11, valve 2 V12, and compressor 19 of the closed-loop unit are opened. Cold water is produced by evaporative cooling and then fed into the condenser 17 of the closed-loop unit for cooling, reducing the energy consumption of the compressor 19. The low-temperature, low-pressure refrigerant after passing through the expansion valve V15 of the closed-loop unit exchanges heat with the user terminal 7 through the heat exchanger 18 of the closed-loop unit.

[0045] Example 3:

[0046] This embodiment provides another method for operating and controlling a combined evaporative cooling and mechanical refrigeration chiller unit. The difference from Embodiment 1 is that it uses a closed-loop unit with a coil and condenser. Figure 3 As shown, when the unit is running, the fan 21, nozzle 22, and water pump 28 of the coil + condenser closed-loop unit are turned on, and the user terminal working fluid is introduced into the condenser 24 of the coil + condenser closed-loop unit. When t > T w When t ≤ T, the evaporative cooling section is activated, and the water pump 27 and valve V19 of the coil + condenser closed-loop unit are opened. Indirect evaporative cooling is performed on the user's end-point working fluid only through spraying from the spray nozzle 22 of the coil + condenser closed-loop unit. w When the mechanical refrigeration section is activated, the compressor 25 of the coil + condenser closed-loop unit, the water pump 27 of the coil + condenser closed-loop unit, and the valve V18 of the coil + condenser closed-loop unit are turned on. Evaporative cooling is used to cool the refrigerant in the coil 23 of the coil + condenser closed-loop unit, reducing the energy consumption of the compressor 25 of the coil + condenser closed-loop unit. Then, the heat exchanger 26 of the coil + condenser closed-loop unit exchanges heat with the working fluid at the user terminal 7 to complete the cooling supply.

[0047] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A method for operating and controlling a combined evaporative cooling and mechanical refrigeration chiller unit, characterized in that: Includes the following steps: S1. Install a temperature detection instrument outdoors to monitor the outdoor temperature T. a ; S2. Based on outdoor temperature T a Calculate the wet-bulb temperature T w ; S3. The control system is based on the wet-bulb temperature T. w The valves of the unit are controlled in accordance with the water supply temperature t; In step S3, the unit is a packed open unit, a coil closed unit, or a coil + condenser closed unit. When using the aforementioned open-type packed unit, during unit operation, the open-type packed unit water pump 2 and the open-type packed unit fan are turned on, and the upper spray nozzles of the open-type packed unit are opened for spraying. Air and water undergo sufficient heat and moisture exchange through the packing, and chilled water is produced by evaporative cooling. When t>T0, the evaporative cooling section is turned on, and the open-type packed unit water pump 1, the open-type packed unit valve 7, and the open-type packed unit valve 8 are turned on. The produced chilled water exchanges heat with the user terminal through a plate heat exchanger to achieve completely natural cooling. When t≤T0, the mechanical refrigeration section is turned on, and the open-type packed unit compressor, the open-type packed unit water pump 1, and the open-type packed unit valve 8 are turned on. Valve 5 and valve 6 of the open-type packing unit allow the produced chilled water to be fed into the condenser of the open-type packing unit to cool the high-temperature, high-pressure refrigerant. After passing through the throttling valve, the water then exchanges heat with the user's terminal via the heat exchanger to complete the cooling supply. In winter, when the system freezes, valve 9 is opened to open the lower spray nozzles of the open-type packing unit for spraying, ensuring normal operation of the unit. When there is a demand for heat, valves 1, 7, and 8 of the open-type packing unit are opened to deliver the hot water, after heat exchange in the condenser, to the user for waste heat utilization.

2. The operation control method for a combined evaporative cooling and mechanical refrigeration chiller unit according to claim 1, characterized in that: In step S2, T w The method for calculating wet-bulb temperature is as follows: T w = T a - ((T a - 14.55) / 2.5) * (1 + 0.00418 * RH * (1 - 0.000016 * P))(1); where, T w T is the wet-bulb temperature. a Outdoor temperature, i.e., dry bulb temperature; RH is relative humidity; P is atmospheric pressure.

3. The operation control method for a combined evaporative cooling and mechanical refrigeration chiller unit according to claim 2, characterized in that: The method for calculating the minimum outlet water temperature T0 is as follows: T0=T w +2 (2)。 4. The operation control method for a combined evaporative cooling and mechanical refrigeration chiller unit according to claim 2, characterized in that: When the aforementioned closed-loop coil unit is used, when t>T w When t ≤ T, the evaporative cooling section is activated, along with the water pump and fan of the closed-loop chiller unit. The spray nozzles of the closed-loop chiller unit are also turned on to spray the working fluid, utilizing indirect evaporative cooling to cool the working fluid within the coils. The water pump, valves 1, 2, 3, and 4 of the closed-loop chiller unit are then opened, allowing the cooled working fluid to be directly supplied to the user's terminal for cooling. w When the mechanical refrigeration section is turned on, the water pump, valve 1, valve 2, and compressor of the closed-loop unit are opened. Cold water is produced by evaporative cooling and then fed into the condenser of the closed-loop unit for cooling, reducing the energy consumption of the compressor. The low-temperature, low-pressure refrigerant after passing through the expansion valve of the closed-loop unit exchanges heat with the user terminal through the heat exchanger of the closed-loop unit.

5. The operation control method for a combined evaporative cooling and mechanical refrigeration chiller unit according to claim 2, characterized in that: When using the coil + condenser closed-loop unit, during unit operation, the coil + condenser closed-loop unit fan, coil + condenser closed-loop unit spray nozzle, and coil + condenser closed-loop unit water pump two are turned on, and the user terminal working fluid is introduced into the coil + condenser closed-loop unit condenser. When t > T w When t ≤ T, the evaporative cooling section is activated, and the water pumps 1, 3, and 4 of the coil + condenser closed-loop unit are opened. Indirect evaporative cooling of the working fluid at the user's end is achieved solely through spraying from the coil + condenser closed-loop unit nozzles. w When the mechanical refrigeration section is activated, the compressor, water pump 1, and valve 2 of the coil + condenser closed-circuit unit are turned on. Evaporative cooling is used to cool the refrigerant in the coil of the coil + condenser closed-circuit unit, reducing the energy consumption of the compressor. Then, the heat exchanger of the coil + condenser closed-circuit unit exchanges heat with the working fluid at the user's terminal to complete the cooling supply.

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