High-water-temperature air-cooled cold water air conditioning unit with natural cooling function

Abstract

The utility model provides a high water temperature type air-cooled cold water air conditioning unit with a natural cooling function, which comprises a compressor operation system and a natural cold source system, and the compressor operation system has a compressor refrigeration mode and an auxiliary refrigeration mode. And when the compression ratio is lower than a preset value, the refrigerant pump is started, liquid is taken from the second port of the air-cooled condenser, and a refrigerant flows through the refrigerant pump and returns to the first port of the compressor, so that a motor cooling loop is formed. And the cold water outlet temperature of the unit is expanded to 30 DEG C from the highest 15 DEG C, so that the stable operation of the unit under the low-pressure-ratio working condition is realized. When the environment temperature is lower than 30 DEG C, the unit enters a natural cooling mode, the compressor can run in a load reduction mode, and along with continuous reduction of the environment temperature, the unit can stop running of the compressor when the temperature is lower than 20 DEG C, and a complete natural cooling mode is entered. Therefore, the COP and the NPLV of the unit can be improved, the operation range of a natural cooling mode is expanded, and the annual comprehensive energy efficiency ratio is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of refrigeration machinery, in particular to a high water temperature air-cooled cold water air conditioning unit with a natural cooling function. Background Art

[0002] Air-cooled chillers are a commonly used refrigeration equipment. The existing chillers with natural cooling function have a cold water outlet temperature range of 7℃ to 15℃. Due to the limitation of cold water temperature, the effect of natural cooling will be greatly limited. Increasing the water temperature can improve the utilization rate of natural cooling. However, for working conditions where the outlet water temperature is above 15℃, the unit has the disadvantage of insufficient motor cooling. Since the compression ratio of the high and low pressures of the compressor in the unit is small, the motor cooling circuit will have insufficient motor cooling due to insufficient liquid supply. Utility Model Content

[0003] The utility model provides a high water temperature air-cooled cold water air conditioning unit with a natural cooling function, which is used to solve the technical problems raised in the background technology.

[0004] The technical solution adopted by the utility model to solve the above technical problems is:

[0005] A high water temperature type air-cooled chilled water air-conditioning unit with a natural cooling function, the air-cooled chilled water air-conditioning unit comprises a compressor operating system and a natural cold source system, the compressor operating system has a compressor refrigeration mode and an auxiliary refrigeration mode; the compressor operating system comprises a compressor, an air-cooled condenser, an expansion valve, an evaporator, a refrigerant pump and a one-way valve; in the compressor refrigeration mode, the outlet end of the compressor is connected to the first port, the second port of the air-cooled condenser, the expansion valve, the first port, the second port of the evaporator, and the first inlet end of the compressor in sequence; in the auxiliary refrigeration mode, the outlet end of the compressor is connected to the first port, the second port of the air-cooled condenser, the refrigerant pump, and the second inlet end of the compressor in sequence, and the one-way valve is connected in parallel to the refrigerant pump. The natural cold source system includes a natural cold source coil, a side water pump and an intermediate heat exchanger; the outlet end of the natural cold source coil is connected to the first port, the second port, the side water pump and the inlet end of the natural cold source coil in sequence to form a water circulation loop, the third port of the intermediate heat exchanger is connected to the refrigerated water return pipe, the fourth port is connected to the refrigerated water outlet pipe, and the other end of the refrigerated water outlet pipe is connected to the third port of the evaporator.

[0006] As a further preferred embodiment of the present invention, when the compressor operation system enters the auxiliary cooling mode, the compression ratio of the compressor is calculated and compared with a preset value;

[0007] When the compression ratio is higher than a preset value, the refrigerant pump is turned off, the one-way valve is opened, liquid is taken from the second port of the air-cooled condenser, and the refrigerant flows through the one-way valve and returns to the first port of the compressor;

[0008] When the compression ratio is lower than a preset value, the refrigerant pump is turned on, the one-way valve is closed, liquid is taken from the second port of the air-cooled condenser, and the refrigerant flows through the refrigerant pump and returns to the first port of the compressor to form a motor cooling circuit. At this time, the refrigerant pump provides sufficient liquid refrigerant to cool the motor.

[0009] As a further preferred embodiment of the present invention, the compressor is one of a scroll compressor, a screw compressor and a centrifugal compressor.

[0010] As a further preferred embodiment of the utility model, the compressor operation system further includes a pressure regulating valve, the first port of the pressure regulating valve is connected to the pipeline between the refrigerant pump and the compressor inlet, and the second port is connected to the pipeline between the second port of the air-cooled condenser and the refrigerant pump. In order to prevent the motor cooling circuit from having too high pressure, a pressure regulating valve is provided, that is, when the pressure is higher than the design value, the valve will open and release pressure to the liquid pipe. If the pressure continues to rise, the opening of the pressure regulating valve will continue to increase until it is fully open.

[0011] As a further preferred embodiment of the present invention, fans are installed at the air inlets of the air-cooled condenser and the natural cooling source coil.

[0012] As a further preferred embodiment of the present invention, when the ambient temperature is lower than 30°C, the unit starts the natural cooling source system and enters the natural cooling mode, at which time the compressor can be operated at reduced load; otherwise, the unit starts the compressor operation system. As the ambient temperature continues to decrease, the unit can stop the compressor below 20°C and enter the completely natural cooling mode.

[0013] As a further preferred embodiment of the present invention, the refrigerant pump is a centrifugal pump or a gear pump.

[0014] As a further preferred embodiment of the present invention, the evaporator is one of a dry evaporator, a flooded evaporator and a falling film evaporator.

[0015] As a further preferred embodiment of the present invention, the intermediate heat exchanger is a shell and tube heat exchanger or a plate heat exchanger.

[0016] Compared with the prior art, the utility model has the following advantages or technical effects:

[0017] The compressor operation system has an auxiliary refrigeration mode. When the compression ratio of the compressor is lower than the preset value, the refrigerant pump is turned on, and liquid is taken from the second port of the air-cooled condenser. The refrigerant flows through the refrigerant pump and returns to the first port of the compressor to form a motor cooling circuit. At this time, the refrigerant pump provides enough liquid refrigerant to cool the motor. This mode can expand the cold water outlet temperature of the chiller from a maximum of 15°C to 30°C, thereby achieving stable operation of the unit under low pressure ratio conditions. When the ambient temperature is lower than 30°C, the unit enters the natural cooling mode, and the compressor can run at a reduced load. As the ambient temperature continues to decrease, the unit can stop the compressor operation when it is below 20°C and enter a completely natural cooling mode. Therefore, the present invention can improve the COP and NPLV of the unit, expand the operating range of the natural cooling mode, and thus improve the overall energy efficiency ratio throughout the year.

[0018] In order to prevent the motor cooling circuit from over-pressure, a pressure regulating valve is set. When the pressure is higher than the design value, the valve will open and release the pressure to the liquid pipe. If the pressure continues to rise, the opening of the pressure regulating valve will continue to increase until it is fully open. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention and its features, appearance and advantages will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings. The same reference numerals indicate the same parts in all the drawings. The drawings are not drawn to scale, but the emphasis is on illustrating the subject matter of the present invention.

[0020] Figure 1 It is a structural schematic diagram of the utility model;

[0021] In the figure, 1. compressor, 2. air-cooled condenser, 3. expansion valve, 4. evaporator, 5. refrigerant pump, 6. check valve, 7. pressure regulating valve, 8. natural cooling source coil, 9. side water pump, 10. intermediate heat exchanger, 11. refrigerated return pipe, 12. refrigerated outlet pipe. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described below in conjunction with the drawings in the embodiments of the present invention. It is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the protection scope of the present invention. Example

[0023] Please refer to the attached Figure 1The utility model provides a high water temperature air-cooled cold water air conditioning unit with natural cooling function, the air-cooled cold water air conditioning unit includes a compressor operation system and a natural cold source system, the compressor operation system has a compressor cooling mode and an auxiliary cooling mode. Specifically:

[0024] When the ambient temperature is higher than 30°C, the system starts the compressor operation system, which includes a compressor 1, an air-cooled condenser 2, an expansion valve 3, an evaporator 4, a refrigerant pump 5 and a one-way valve 6. In the compressor refrigeration mode, the outlet of the compressor 1 is connected to the first port and the second port of the air-cooled condenser 2, the expansion valve 3, the first port and the second port of the evaporator 4, and the first inlet of the compressor 1 in sequence; in the auxiliary refrigeration mode, the outlet of the compressor 1 is connected to the first port and the second port of the air-cooled condenser 2, the refrigerant pump 5, and the second inlet of the compressor 1 in sequence, and the one-way valve 6 is connected in parallel to the refrigerant pump 5.

[0025] When the ambient temperature is lower than 30°C, the system starts the natural cooling system and enters the natural cooling mode. The natural cooling system includes a natural cooling coil 8, a side water pump 9 and an intermediate heat exchanger 10. The outlet of the natural cooling coil 8 is connected to the first port, the second port, the side water pump 9 and the inlet of the natural cooling coil 8 of the intermediate heat exchanger 10 in sequence to form a water circulation loop, which is the inside of the unit. The third port of the intermediate heat exchanger 10 is connected to the refrigerated water return pipe 11, and the fourth port is connected to the refrigerated water outlet pipe 12. The other end of the refrigerated water outlet pipe 12 is connected to the third port of the evaporator 4, which is the customer side.

[0026] To further illustrate, the refrigeration mode of the compressor operation system is determined by calculating the compression ratio of the compressor and comparing it with a preset value. When the compression ratio is higher than the preset value, the cooling circuit of the compressor motor is a conventional principle, the refrigerant pump 5 is closed, the one-way valve 6 is opened, and liquid is taken from the second port of the air-cooled condenser 2. The refrigerant flows through the one-way valve 6 and returns to the first port of the compressor 1. When the compression ratio is lower than the preset value, the refrigerant pump 5 is opened, the one-way valve 6 is closed, and liquid is taken from the second port of the air-cooled condenser 2. The refrigerant flows through the refrigerant pump 5 and returns to the first port of the compressor 1 to form a motor cooling circuit. At this time, the refrigerant pump 5 provides sufficient liquid refrigerant to cool the motor.

[0027] Further explanation, the compressor operation system also includes a pressure regulating valve 7, the first port of the pressure regulating valve 7 is connected to the pipeline between the refrigerant pump 5 and the inlet end of the compressor 1, and the second port is connected to the pipeline between the second port of the air-cooled condenser 2 and the refrigerant pump 5. In order to prevent the motor cooling circuit pressure from being too high, the pressure regulating valve 7 is set, that is, when the pressure is too high, the valve will open and release pressure to the liquid pipe. If the pressure continues to rise, the opening of the pressure regulating valve will continue to increase until it is fully open.

[0028] It is further explained that due to the high temperature of the cold water, the utilization rate of the natural cooling function of the unit is high. In the natural cooling mode, the compressor 1 stops, the side water pump 9 and the fan start, and the water system inside the unit will start to circulate and be cooled by the air. The cold water on the client side is cooled by heat exchange through the natural cold source intermediate heat exchanger 10. The present invention can expand the cold water outlet temperature of the chiller from a maximum of 15°C to 30°C, thereby achieving stable operation of the unit under low pressure ratio conditions. When the ambient temperature is lower than 30°C, the unit starts the natural cold source system and enters the natural cooling mode. At this time, the compressor can be operated at a reduced load. As the ambient temperature continues to decrease, the unit can stop the compressor below 20°C and enter a completely natural cooling mode. Therefore, the present invention can improve the COP and NPLV of the unit, expand the operating range of the natural cooling mode, and thus improve the overall energy efficiency ratio throughout the year.

[0029] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, is also included in the patent protection scope of the present invention.

Claims

1. A high water temperature air-cooled chiller with natural cooling function, characterized in that: The air-cooled chilled water air conditioning unit comprises a compressor operation system and a natural cold source system, wherein the compressor operation system has a compressor refrigeration mode and an auxiliary refrigeration mode; The compressor operation system comprises a compressor (1), an air-cooled condenser (2), an expansion valve (3), an evaporator (4), a refrigerant pump (5) and a one-way valve (6); in a compressor refrigeration mode, the outlet end of the compressor (1) is connected in sequence to a first port and a second port of the air-cooled condenser (2), the expansion valve (3), the first port and the second port of the evaporator (4), and a first inlet end of the compressor (1); in an auxiliary refrigeration mode, the outlet end of the compressor (1) is connected in sequence to a first port and a second port of the air-cooled condenser (2), the refrigerant pump (5), and a second inlet end of the compressor (1), and the one-way valve (6) is connected in parallel to the refrigerant pump (5); The natural cold source system comprises a natural cold source coil (8), a side water pump (9) and an intermediate heat exchanger (10); the outlet end of the natural cold source coil (8) is connected in sequence to the first port and the second port of the intermediate heat exchanger (10), the side water pump (9) and the inlet end of the natural cold source coil (8) to form a water circulation loop; the third port of the intermediate heat exchanger (10) is connected to a refrigerated water return pipe (11), the fourth port is connected to a refrigerated water outlet pipe (12), and the other end of the refrigerated water outlet pipe (12) is connected to the third port of the evaporator (4).

2. A high water temperature air-cooled chilled water air conditioning unit with natural cooling function according to claim 1, characterized in that: When the compressor operation system enters the auxiliary cooling mode, calculating the compression ratio of the compressor (1) and comparing it with a preset value; When the compression ratio is higher than a preset value, the refrigerant pump (5) is closed, the one-way valve (6) is opened, liquid is taken from the second port of the air-cooled condenser (2), and the refrigerant flows through the one-way valve (6) and returns to the first port of the compressor (1); When the compression ratio is lower than a preset value, the refrigerant pump (5) is turned on, the one-way valve (6) is closed, liquid is taken from the second port of the air-cooled condenser (2), and the refrigerant flows through the refrigerant pump (5) and returns to the first port of the compressor (1).

3. The high water temperature air-cooled chiller with natural cooling function according to claim 1, characterized in that: The compressor (1) is a scroll / screw / centrifugal compressor.

4. A high water temperature air-cooled chilled water air conditioning unit with natural cooling function according to claim 1, characterized in that: The compressor operation system further comprises a pressure regulating valve (7), wherein a first port of the pressure regulating valve (7) is connected to a pipeline between the refrigerant pump (5) and an inlet end of the compressor (1), and a second port of the pressure regulating valve (7) is connected to a pipeline between a second port of the air-cooled condenser (2) and the refrigerant pump (5).

5. The high water temperature air-cooled chiller with natural cooling function according to claim 1, characterized in that: Fans are installed at the air inlets of the air-cooled condenser (2) and the natural cooling source coil (8).

6. A high water temperature air-cooled chiller with natural cooling function according to claim 1, characterized in that: When the ambient temperature is lower than 30℃, the unit starts the natural cooling system and enters the natural cooling mode; otherwise, the unit starts the compressor operation system.

7. A high water temperature air-cooled chilled water air conditioning unit with natural cooling function according to claim 1, characterized in that: The refrigerant pump (5) is a centrifugal pump or a gear pump.

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