CN112963977A

CN112963977A - Centrifugal compressor and water chilling unit

Info

Publication number: CN112963977A
Application number: CN202110367129.6A
Authority: CN
Inventors: 邱韦淇; 王作林; 王作凤; 王玉俊; 王作坤; 王静
Original assignee: Qingdao Tengyuan Design Institute Co Ltd
Current assignee: Qingdao Tengyuan Design Institute Co Ltd
Priority date: 2021-04-06
Filing date: 2021-04-06
Publication date: 2021-06-15

Abstract

The invention discloses a centrifugal compressor and a water chilling unit, wherein a bearing of a second impeller of the centrifugal compressor is connected with the bearing of a first impeller through a speed change device; the first impeller is arranged in the first diffuser, one side of the first diffuser is provided with a first air suction port, and the other side of the first diffuser is provided with a first air outlet; the second impeller is arranged in the second diffuser, one side of the second diffuser is provided with a second air suction port, and the other side of the second diffuser is provided with a second air outlet; the efficiency of refrigeration cycle can be improved, the performance coefficient of refrigeration can be improved, and the energy-saving performance can be improved; the exhaust temperature of the compressor is reduced, the operation condition of the compressor is improved, and the operation life of the compressor is prolonged; the centrifugal water chilling unit has the advantages of improving the operation efficiency of the centrifugal water chilling unit, reducing the use energy consumption of the air conditioner, keeping the advantages of large refrigerating capacity, simple and compact structure, balanced operation, reliable operation, high operation efficiency and the like, and is widely applied to large public buildings.

Description

Centrifugal compressor and water chilling unit

Technical Field

The invention belongs to the technical field of compressors, and particularly relates to a centrifugal compressor and a water chilling unit.

Background

With the development of economy and society and the improvement of living standard of people, people have higher and higher requirements on the comfort in buildings. The problem of operating energy consumption of air conditioning systems is also getting more and more attention from researchers and scholars. In the process of building the indoor environment of a large building, a water chilling unit is often needed. One of the most important components in a chiller is the compressor. The currently commonly used forms of compressor are: piston, screw, centrifugal. The water chilling unit of which the compressor is a centrifugal compressor is adopted, and has the characteristics of large refrigerating capacity, simple and compact structure, balanced operation, reliable operation, high operation efficiency and the like, so that the water chilling unit is widely applied to large public buildings, particularly data center machines, medical buildings and urban complex buildings. Therefore, a new centrifugal compressor is needed to improve the operation efficiency of the centrifugal chiller and reduce the energy consumption of the air conditioner.

Disclosure of Invention

The invention provides a centrifugal compressor and a water chilling unit, which are used for improving the operation efficiency of the centrifugal water chilling unit, reducing the use energy consumption of an air conditioner, keeping the characteristics of large refrigerating capacity, simple and compact structure, balanced operation, reliable operation, high operation efficiency and the like, and are suitable for being widely applied to large public buildings, particularly data center machines, medical buildings and urban complex buildings.

The invention specifically comprises the following scheme:

the centrifugal compressor comprises a first impeller, a first diffuser, a second impeller and a second diffuser; the bearing of the second impeller is connected with the bearing of the first impeller through a speed change device; the first impeller is arranged in the first diffuser, one side of the first diffuser is provided with a first air suction port, and the other side of the first diffuser is provided with a first air outlet; the second impeller is installed in the second diffuser, and one side of the second diffuser is provided with a second air suction port, and the other side of the second diffuser is provided with a second air outlet.

The refrigerant gas of the centrifugal compressor flows into the compressor through the first air inlet, is compressed by the first impeller, is discharged through the first air outlet after being diffused by the first diffuser, flows into the second air inlet, is compressed by the second impeller, and flows out of the compressor after being diffused by the second diffuser.

Wherein further, the bearing of the first impeller or the second impeller is connected with the bearing of the motor; an inlet guide vane positioned in the first air suction port is arranged in the first diffuser. A first diffuser chamber with a cavity structure is arranged in the first diffuser. And a second diffuser chamber with a cavity structure is arranged in the second diffuser. The transmission may be a geared transmission. And the bearing of the first impeller or the second impeller is connected with the bearing of the motor through a gear mechanism. The centrifugal compressor is provided with a housing. The shell is provided with a compressor air suction port communicated with the first air suction port and a compressor exhaust port communicated with the second air outlet.

The water chilling unit comprises the centrifugal compressor, wherein the exhaust port of the compressor is connected with the inlet of the condenser, the outlet of the condenser is connected with the throttling device, the throttling device is connected with the inlet of the evaporator, and the outlet of the evaporator is connected with the air suction port of the compressor.

The invention has the beneficial effects that:

the centrifugal compressor and the water chilling unit can improve the efficiency of refrigeration cycle, improve the performance coefficient of refrigeration and greatly improve the energy-saving performance; the exhaust temperature of the compressor can be reduced, the operation condition of the compressor is improved, and the operation life of the compressor is prolonged; the system can realize the function of changing the compression process curve of one compressor, can be matched with an advanced control system, and is widely applied to a high-efficiency refrigerating system; meanwhile, the running efficiency of the centrifugal water chilling unit can be improved, the use energy consumption of the air conditioner is reduced, the advantages of large refrigerating capacity, simple and compact structure, balanced running, reliable operation, high running efficiency and the like are kept, and the centrifugal water chilling unit can be widely applied to large public buildings, particularly data center machines, medical buildings and urban complex buildings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic view of the internal structure of a centrifugal compressor of the present invention.

Fig. 2 is a schematic view showing the overall structure of the centrifugal compressor of the present invention.

Fig. 3 is a schematic structural diagram of the water chilling unit of the present invention.

Fig. 4 is a pressure-enthalpy diagram of the refrigerant.

In the figure, 1 is a first impeller, 2 is a first diffuser, 3 is a second impeller, 4 is a second diffuser, 5 is a speed change device, 6 is a first air intake port, 7 is a first air outlet port, 8 is a second air intake port, 9 is a second air outlet port, 10 is a motor, 11 is an inlet guide vane, 12 is a first diffuser, 13 is a second diffuser, 14 is a housing, 15 is a compressor air intake port, 16 is a compressor air exhaust port, 17 is a condenser, 18 is a throttling device, 19 is an evaporator, and 20 is a compressor.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Example 1

A centrifugal compressor, see fig. 1, comprising a first impeller 1, a first diffuser 2, a second impeller 3 and a second diffuser 4; the bearing of the first impeller 1 is connected with the bearing of the motor 10; the bearing of the second impeller 3 is connected with the bearing of the first impeller 1 through a speed changing device 5; the first impeller 1 is arranged in the first diffuser 2, one side of the first diffuser 2 is provided with a first air suction port 6, and the other side of the first diffuser 2 is provided with a first air outlet 7; the second impeller 3 is installed in the second diffuser 4, one side of the second diffuser 4 is provided with a second air suction port 8, and the other side is provided with a second air outlet 9.

In the centrifugal compressor of the present embodiment, the refrigerant gas flows into the compressor through the first suction port 6, is compressed by the first impeller 1, is diffused by the first diffuser 2, is discharged through the first discharge port 7, flows into the second suction port 8, is compressed by the second impeller 3, is diffused by the second diffuser 4, and then flows out of the compressor. The bearing end shown by the rotational arrow in fig. 1 is connected to the motor 10.

Example 2

A centrifugal compressor, similar to embodiment 1 except that, referring to fig. 2, a bearing of a first impeller 1 or a second impeller 3 is connected to a bearing of a motor 10; an inlet guide vane 11 located in the first air intake 6 is provided in the first diffuser 2. A first diffuser chamber 12 of a cavity structure is provided in the first diffuser 2. A second diffuser chamber 13 of a cavity structure is arranged in the second diffuser 4. The transmission 5 may be a geared transmission. The bearing of the first impeller 1 or the second impeller 3 is connected to the bearing of the motor 10 through a gear mechanism. The centrifugal compressor is provided with a housing 14. The casing 14 is provided with a compressor suction port 15 communicating with the first suction port 6 and a compressor discharge port 16 communicating with the second discharge port 9.

The longitudinal sections of the first diffuser 2 and the second diffuser 4 may be transverse trapezoids, especially transverse isosceles trapezoids, and the tops of the trapezoids are located on the sides of the first air suction port 6 and the second air suction port 8 respectively. The inlet guide vanes 11 may have a triangular plate structure, and the number of the inlet guide vanes 11 may be at least two, and the inlet guide vanes 11 are uniformly distributed on the inner wall of the first diffuser 2 at the first suction port 6 in the first diffuser chamber 12. The inlet guide vanes 11 function as: the size of the inlet of the first air suction port 6 is changed by changing the angle of the blades of the inlet guide vanes 11 by adjusting the flow rate of the refrigerant flowing into the compressor.

The inlet guide vanes 11 may be welded to the inner wall of the first pressure expansion chamber 12. The first impeller 1 is mounted in a first pressure expansion chamber 12; the second impeller 3 is mounted in a second pressure expansion chamber 13. The housing 14 may be a transverse cylindrical structure. The first impeller 1, the first diffuser 2, the second impeller 3, the second diffuser 4, the speed changing device 5, the first air suction port 6, the first air outlet 7, the second air suction port 8, the second air outlet 9, the motor 10, the inlet guide vane 11, the first diffusion chamber 12 and the second diffusion chamber 13 are all located in the casing 14.

Example 3

A water chiller, see figure 3, comprising a centrifugal compressor as described in either embodiment 1 or embodiment 2, the compressor discharge 16 being connected to the inlet of a condenser 17, the outlet of the condenser 17 being connected to a throttling device 18, the throttling device 18 being connected to the inlet of an evaporator 19, the outlet of the evaporator 19 being connected to the compressor suction 15.

The operation principle of the centrifugal compressor of any of the above embodiments: the first impeller 1 rotates at a high speed under the driving action of the motor 10 to generate centrifugal force, so that the low-temperature low-pressure refrigerant gas sucked from the suction port 15 of the compressor obtains energy and is changed into medium-temperature medium-pressure refrigerant gas; then the refrigerant is pressurized by the second impeller 3, the refrigerant is changed from the gas with medium temperature and pressure into the refrigerant gas with high temperature and pressure, and then the refrigerant gas is discharged to a condenser 17 through a compressor exhaust port 16 to be condensed and release heat, thereby completing the refrigeration cycle. The difference from the conventional refrigeration cycle is that the bearing of the first impeller 1 is not coaxial with the bearing of the second impeller 3, the speed change device 5 is signaled by the controller, the rotation speeds of the first impeller 1 and the second impeller 3 are different, and the compression curve can be changed by changing the rotation speed ratio of the first impeller 1 and the second impeller 3; by matching the rotational speeds of the first impeller 1 and the second impeller 3, the compression process is made to be a pressure-enthalpy diagram as shown in fig. 4, so that the centrifugal compressor can be operated more efficiently.

Referring to fig. 4, the energy saving principle of the centrifugal compressor of any of the above embodiments: the low-temperature and low-pressure refrigerant gas (state I) is compressed by the first impeller 1 to be changed into a state II, and the refrigerant gas is adjusted by the speed changing device 5, so that the compression curve of the second impeller 3 is different from that of the first impeller 1, and the refrigerant gas is compressed by the second impeller 3 from the state II to be changed into a state III. Then the refrigerant is discharged from the air outlet 16 of the compressor, enters the condenser 17, becomes refrigerant liquid with low temperature and high pressure (state IV), is throttled by the throttling device 18, becomes refrigerant liquid with low temperature and low pressure (state V), evaporates and absorbs heat in the evaporator 19, changes from the state V to the state I, and continuously circulates. As can be seen from the pressure-enthalpy diagram shown in fig. 4, the compression process of the centrifugal compressor of the above embodiment is i-ii-iii, not the compression process i-ii-vi of the conventional compressor. According to the prior knowledge of engineering thermodynamics, in an ideal refrigeration cycle, the area of the envelope of the process curve of the refrigeration cycle is equal to the power consumption of the compressor. After the centrifugal compressor of the embodiment is adopted, the power consumption of the compressor is the area enveloped by the processes I-II-III-IV-V-I; and the power consumption of the compressor of the conventional compression refrigeration cycle is I-II-VI-IV-V-I. Meanwhile, the refrigerating capacity of the two refrigerating cycles is the same (from V-I). Therefore, after the centrifugal compressor of the embodiment is adopted, the refrigeration coefficient is improved compared with the conventional refrigeration cycle. In addition, compared with the processes I-II-VI, the centrifugal compressor of the embodiment has lower exhaust temperature, and the centrifugal compressor of the embodiment has better operation condition, which helps to prolong the operation life of the compressor.

The above description is only an example of the present application and is not intended to limit the present application. Various modifications and changes may occur to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A centrifugal compressor comprises a first impeller (1), a first diffuser (2), a second impeller (3) and a second diffuser (4); the device is characterized in that a bearing of the second impeller (3) is connected with the bearing of the first impeller (1) through a speed changing device (5); the first impeller (1) is arranged in the first diffuser (2), one side of the first diffuser (2) is provided with a first air suction port (6), and the other side of the first diffuser is provided with a first air outlet (7); the second impeller (3) is installed in the second diffuser (4), a second air suction port (8) is formed in one side of the second diffuser (4), and a second air outlet (9) is formed in the other side of the second diffuser.

2. A centrifugal compressor according to claim 1, characterized in that the bearing of the first impeller (1) or the second impeller (3) is connected with the bearing of the motor (10).

3. A centrifugal compressor according to claim 1, characterized in that inlet guide vanes (11) are provided in the first diffuser (2) in the first suction port (6).

4. The centrifugal compressor according to claim 1, characterized in that the first diffuser (2) is provided with a first diffuser chamber (12) of a cavity structure; and a second diffuser chamber (13) with a cavity structure is arranged in the second diffuser (4).

5. A centrifugal compressor according to claim 1, characterized in that the speed change means (5) can be a gear transmission speed change means.

6. A centrifugal compressor according to claim 1, characterized in that the bearings of the first impeller (1) or the second impeller (3) and the bearings of the motor (10) are connected by a gear mechanism.

7. A centrifugal compressor according to claim 1, characterized in that it is provided with a housing (14).

8. A centrifugal compressor according to claim 7, wherein the housing (14) is provided with a compressor suction port (15) communicating with the first suction port (6) and a compressor discharge port (16) communicating with the second discharge port (9).

9. A chiller including a centrifugal compressor according to any one of claims 1 to 8, characterised in that the compressor discharge (16) is connected to the inlet of a condenser (17), the outlet of the condenser (17) is connected to a throttling means (18), the throttling means (18) is connected to the inlet of an evaporator (19), and the outlet of the evaporator (19) is connected to the compressor suction (15).