US20110094251A1

US20110094251A1 - Dual turbo centrifugal chiller

Info

Publication number: US20110094251A1
Application number: US12/796,014
Authority: US
Inventors: Kil Young Kim; Jin Sung Kim; Tae Jin Kang
Original assignee: Individual
Current assignee: LG Electronics Inc
Priority date: 2009-10-27
Filing date: 2010-06-08
Publication date: 2011-04-28
Also published as: KR20110045574A; KR101065549B1; CN102052796A

Abstract

A dual turbo centrifugal chiller includes: first and second evaporators connected in series or in parallel; first and second condensers connected in series or in parallel; and first and second compressors including impellers, wherein cold water passes through the second evaporator after passing through the first evaporator, and cooling water passes through the second condenser after passing through the first condenser, the first compressor containing a refrigerant connects the first condenser to the second evaporator, and the second compressor containing a refrigerant connects the second condenser to the first evaporator, and the impellers of the first compressor and second compressor are rotated simultaneously using a single driving unit.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application No. 10-2009-0102209, filed on Oct. 27, 2009, and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which in its entirety are herein incorporated by reference.

BACKGROUND

1. Field
This disclosure relates to a dual turbo centrifugal chiller, particularly to a dual turbo centrifugal chiller configured to decrease head of a compressor among components of two individual chillers, decrease the size of the chiller, and increase efficiency.
2. Description of the Related Art
A general chiller includes a compressor, an evaporator, a condenser, and an expansion valve, and circulates a refrigerant to transfer heat from the evaporator to the condenser through heat exchange.
FIG. 1 is a diagram schematically illustrating a general chiller 10.
As illustrated in FIG. 1, the chiller 10 includes an evaporator 30, a condenser 20, and a compressor 40. Cold water 31 flows through the evaporator 30, and cooling water 21 flow through the condenser 20.
The compressor 40 in which a refrigerant 51, 52 is circulated connects the evaporator 30 to the condenser 20. The refrigerant 51 that passes through the evaporator 30 flows into the compressor 40 through an inlet portion 47 of the compressor 40, and the refrigerant 52 compressed by two- stage impellers 41 and 42 flows out of an outlet portion 48 of the compressor 40 and then flows into the condenser 20.
As illustrated in FIG. 1, in the compressor 40, the two- stage impellers 41 and 42 are provided on a shaft 43, and the impellers 41 and 42 are rotated as the shaft 43 is rotated by a motor 45. Here, gears 44 and 46 are provided to connect the motor 45 to the shaft 43 so as to transmit torque. Although not shown in the figure, a thrust bearing may be connected between the gear 44 and the shaft 43.
In the general compressor 40, a load applied to the bearing increases because a thrust that is transferred to the gears 46 and 44 is focused in one direction, and, thus, a load applied to the motor 45 also increases. As the load applied to the motor 45 increases, an outlet temperature of the cold water increases, which results in an increase in head of the compressor. As a result, the efficiency of the compressor is decreased.
In order to decrease the head of the compressor and increase the efficiency of the chiller, a ‘dual turbo centrifugal chiller’ which includes two chillers connected to each other has been used. The dual turbo centrifugal chiller has an increased capacity by increasing the chilling efficiency of the chiller itself. In the dual turbo centrifugal chiller, two compressors are provided. However, in the existing dual turbo centrifugal chiller, one of the two compressors has a higher head than the other. Therefore, the two compressors have to be independently designed and manufactured. That is, a driving unit for driving an impeller of each of the compressors is additionally needed, and the entire size of the chiller is increased. Accordingly, as described above, there is a problem in that the efficiency of the compressor is decreased.

SUMMARY

This disclosure provides a dual turbo centrifugal chiller in which two compressors, two evaporators, and two condensers are included to decrease heads of the compressors, the compressors are configured to operate with the same head, and impellers of the compressors are driven by a single driving unit, thereby achieving a decrease in size and an increase in efficiency.
In one aspect, there is a provided a dual turbo centrifugal chiller including: first and second evaporators connected in series or in parallel; first and second condensers connected in series or in parallel; and first and second compressors including impellers, wherein cold water passes through the second evaporator after passing through the first evaporator, and cooling water passes through the second condenser after passing through the first condenser, the first compressor containing a refrigerant connects the first condenser to the second evaporator, and the second compressor containing a refrigerant connects the second condenser to the first evaporator, and the impellers of the first compressor and the second compressor are rotated simultaneously using a single driving unit.
In addition, the impellers of the first and second compressors may be connected with a single rotation shaft, and the impellers of the first and second compressors may be rotated simultaneously as the rotation shaft is rotated using the driving unit.
In addition, the driving unit may be connected to the center of the rotation shaft, and the impellers of the first and second compressors may be opposed with the center of the rotation shaft between them.
In addition, inlet portions of the first and second compressors may be provided with inlet guide vanes (IGVs) respectively.
In addition, the first and second compressors may have different capacities from each other.
Since the dual turbo centrifugal chiller including the two evaporators, the two compressors and the two condensers maintains the reduced head of each compressor, it is possible to achieve the optimal performance of the compressor.
In addition, since the impellers of the two compressors are driven simultaneously using the single driving unit, it is possible to implement the compressor having a small size and high efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the disclosed exemplary embodiments will be more apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a diagram schematically illustrating a general chiller;

FIG. 2 is a diagram schematically illustrating a dual turbo centrifugal chiller according to an embodiment; and

FIG. 3 is a diagram schematically illustrating a dual turbo centrifugal chiller according to another embodiment.

DETAILED DESCRIPTION

Exemplary embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth therein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. In the description, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, the use of the terms a, an, etc. does not denote a limitation of quantity, but rather denotes the presence of at least one of the referenced item. It will be further understood that the terms “comprises” and/or “comprising”, or “includes” and/or “including” when used in this specification, specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In the drawings, like reference numerals in the drawings denote like elements. The shape, size and regions, and the like, of the drawing may be exaggerated for clarity.
FIG. 2 is a diagram schematically illustrating a dual turbo centrifugal chiller 101 according to an embodiment.
As illustrated in FIG. 2, according to the embodiment, a first evaporator 121 and a second evaporator 122 are connected in series. Cold water 123 flows into an end of the first evaporator 121 connected in series, passes through the first evaporator 121, passes through the second evaporator 122, and then flows out.
A first condenser 111 and a second condenser 112 are connected in series. Cooling water 113 passes through the first condenser 111, flows into the second condenser 112, passes through the second condenser 112, and then flows out.
A first compressor 131 is connected to the first condenser 111 and the second evaporator 122 such that a refrigerant of the first compressor 131 is circulated to exchange heat with the cooling water 113 of the first condenser 111 and the cold water 123 of the second evaporator 122. A second compressor 132 is connected to the second condenser 112 and the first evaporator 121 such that a refrigerant of the second compressor 132 is circulated to exchange heat with the cooling water 113 of the second compressor 112 and the cold water 123 of the first evaporator 121.
A temperature of the cold water that flows into the first evaporator 121 is 12° C., a temperature of the cold water that flows out of the second evaporator 122 is 7° C., a temperature of the cooling water that flows into the first condenser 111 is 32° C., and a temperature of the cooling water that flows out of the second condenser 112 is 37° C.
Without consideration of leaving temperature differences (LTDs) of the evaporator and the condenser, a head of the first compressor 131 is 27.5° C. (34.5° C.-7° C.), and a head of the second compressor 132 is also 27.5° C. (37° C.-9.5° C.).
In the dual turbo centrifugal chiller 101 according to the embodiment, as described above, the heads of the two compressors 131 and 132 are equal to each other. Accordingly, as described below, a design for simultaneously driving impellers of the two compressors using a single driving unit may be easily achieved.
Hereinafter, configurations of the two compressors 131 and 132 according to the embodiment will be described with reference to FIG. 2.
According to the embodiment, the first compressor 131 is a two-stage compression system having two impellers 145 and 146. A refrigerant 151 flows out of the second evaporator 122 into the first compressor 131 through an inlet portion 141 of the first compressor 131, and the refrigerant is compressed while passing through the impellers 145 and 146. The compressed refrigerant 152 flows out of the first compressor 131 through an outlet portion 142 and flows into the first condenser 111.
The second compressor 132 is a two-stage compression system having two impellers 143 and 144. A refrigerant 153 that flows out of the first evaporator 121 flows into the second compressor 132 through an inlet portion 143 of the second compressor 132, and the refrigerant is compressed while passing through the impellers 143 and 144. The compressed refrigerant 154 flows out of the second compressor 132 through an outlet portion 144 and flows into the second condenser 122.
According to the embodiment, a single driving unit 163 for rotating the impellers 143, 144, 145, and 146 of the two compressors 131 and 132 is provided. In this embodiment, an electric motor is used as the driving unit 163.
The impellers 143, 144, 145, and 146 of the two compressors 131 and 132 are connected with a rotation shaft 161. A gear 162 is provided at the center of the rotation shaft 161, the impellers 145 and 146 of the first compressor 131 and the impellers 143 and 144 of the second compressor 132 are opposed with the center of the rotation shaft 161 between them. An end portion of the driving unit 163 is connected to a gear, and the gear connected to the driving unit 163 is engaged with a gear 162 of the rotation shaft 161. In this configuration, the single driving unit 163 rotates the rotation shaft 161, and as the rotation shaft 161 is rotated, the impellers 143, 144, 145, and 146 of the two compressors 131 and 132 are rotated simultaneously.
According to the embodiment, since the two individual compressors 131 and 132 are driven by the single driving unit 163, the entire volume of the compressor system is reduced. Therefore, the entire size of the dual turbo centrifugal chiller 101 is reduced.
In addition, since the impellers of the two compressors are disposed symmetrically, thrusts applied to both ends of the gear 162 occur in the opposite direction and cancel each other out. Accordingly, a load applied to a bearing (not shown) used for the gear 162 decreases, which results in a decrease in the load applied to the driving unit 163 and an increase in the efficiency of the driving unit 163. The increase in the efficiency of the driving unit 163 causes a decrease in the outlet temperature of the cooling water, and this causes a decrease in the heads of the compressors 131 and 132. Accordingly, there are advantages in that the efficiency of the entire compression system increases, and the efficiency of the entire chiller increases. In addition, in designing the bearing, a design of the bearing without concern about the thrust applied in particular direction may be achieved.
According to the embodiment, the inlet portions of the first and second compressors 131 and 132 are provided with inlet guide vanes (IGVs) for adjusting loads applied thereto in order to facilitate load adjustment.
According to the embodiment, since the first and second compressors 131 and 132 are separated from each other, various combinations of capacity may be attained with the compressors and the heat exchangers (the condensers and the evaporators). For example, the capacities of the compressors 131 and 132 may be set to 1,000 RT and 500 RT, respectively. The size of the heat exchanger is determined according to the capacity of the compressor. Even in this case, the impellers of the compressors are disposed symmetrically on the single rotation shaft, and since the impellers are disposed symmetrically, the thrust cancellation effect of the bearing is exhibited even in the case where the capacities of the two compressors are different from each other.
In this embodiment, the two evaporators 121 and 122 are connected in series, and the two condensers 111 and 112 are connected in series, however, the embodiment is not limited to that configuration. Hereinafter, another embodiment will be described with reference to FIG. 3.
FIG. 3 is a diagram schematically illustrating a dual turbo centrifugal chiller 201 according to another embodiment.
As illustrated in FIG. 3, in the dual turbo centrifugal chiller 201 according to this embodiment, a first evaporator 221 and a second evaporator 222 are connected in parallel. Cold water 223 flows into an end of the first evaporator 221 connected in parallel and flows out of the other end of the first evaporator 221, flows into an end of the second evaporator 222, passes through the second evaporator 222, and flows out of the other end of the second evaporator 222.
A first condenser 211 and a second condenser 212 are connected in parallel. Cooling water 213 flows into an end of the first condenser 211 connected in parallel, flows out of the other end of the first condenser 211, flows into an end of the second condenser 212, passes through the second condenser 212, and flows out of the other end of the second condenser 212.
A first compressor 231 is connected to the first condenser 211 and the second evaporator 222, and a refrigerant of the first compressor 231 is circulated to exchange heat with the cooling water of the first condenser 211 and the cold water of the second evaporator 222. A second compressor 232 is connected to the second condenser 212 and the first evaporator 221, and a refrigerant of the second compressor 232 is circulated to exchange heat with the cooling water of the second condenser 212 and the cold water of the first evaporator 221.
Here, a temperature of the cold water that flows into the first evaporator 221 is 12° C., a temperature of the cold water that flows out of the second evaporator 222 is 7° C., a temperature of the cooling water that flows into the first condenser 211 is 32° C., and a temperature of the cooling water that flows out of the second condenser 212 is 37° C.
Without consideration of LTDs of the evaporators and the compressors, a head of the first compressor 231 is 27.5° C. (34.5° C.-7° C.), and a head of the second compressor 232 is also 27.5° C. (37° C.-9.5° C.). That is, the heads of the two compressors are equal to each other.
Since connection relationships between impellers 245, 246, 247, and 248 of the compressors 231 and 232, the rotation shaft 161, a gear 262, and a driving unit 263 provided in the dual turbo centrifugal chiller 201 according to this embodiment, and a flow of a refrigerant 251, 252, 253, and 254 at inlet and outlet portions 243 and 244 of the compressor are the same as those of the embodiment illustrated in FIG. 2, a detailed description thereof will be omitted.
Although the two embodiments of the dual turbo centrifugal chiller have been described, this disclosure is not limited thereto. That is to say, the two evaporators may be connected in serial or in parallel, and the two condensers may be connected in serial or in parallel. In this case, it should be understood by those skilled in the art that cold water passes through a first evaporator and a second evaporator, cooling water passes through a second condenser after passing through a first condenser, a first compressor containing a refrigerant is connected to the first condenser and the second evaporator, and a second compressor containing a refrigerant is connected to the second condenser and the first evaporator, thereby implementing a dual turbo centrifugal chiller in which heads of the two compressor are equal to each other.
While the exemplary embodiments have been shown and described, it will be understood by those skilled in the art that various changes in form and details may be made thereto without departing from the spirit and scope of this disclosure as defined by the appended claims.
In addition, many modifications can be made to adapt a particular situation or material to the teachings of this disclosure without departing from the essential scope thereof. Therefore, it is intended that this disclosure not be limited to the particular exemplary embodiments disclosed as the best mode contemplated for carrying out this disclosure, but that this disclosure will include all embodiments falling within the scope of the appended claims.

Claims

1. A dual turbo centrifugal chiller, comprising:

first and second evaporators connected in series or in parallel;

first and second condensers connected in series or in parallel; and

first and second compressors including impellers,

wherein cold water passes through the second evaporator after passing through the first evaporator, and cooling water passes through the second condenser after passing through the first condenser,

the first compressor containing a refrigerant connects the first condenser to the second evaporator, and the second compressor containing a refrigerant connects the second condenser to the first evaporator, and

the impellers of the first compressor and second compressor are rotated simultaneously using a single driving unit.

2. The dual turbo centrifugal chiller according to claim 1,

wherein the impellers of the first and second compressors are connected with a single rotation shaft, and

the impellers of the first and second compressor are rotated simultaneously as the rotation shaft is rotated using the driving unit.

3. The dual turbo centrifugal chiller according to claim 2,

wherein the driving unit is connected to the center of the rotation shaft, and

the impellers of the first and second compressors are opposed with the center of the rotation shaft between them.

4. The dual turbo centrifugal chiller according to claim 1, wherein inlet portions of the first and second compressors are provided with inlet guide vanes (IGVs) respectively.

5. The dual turbo centrifugal chiller according to claim 3, wherein the first and second compressors have different capacities from each other.