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Title:
COOLING OF LIQUIDS USING PHASE CHANGE
Document Type and Number:
WIPO Patent Application WO/2019/106561
Kind Code:
A1
Abstract:
A cooling apparatus (100) includes an evaporative cooling unit (108) and a refrigeration unit (114) such that a cooling liquid exiting the evaporative cooling unit (108) is further cooled by an evaporator (118) of the refrigeration unit (114) in a heat exchanger (122). The cooling liquid absorbs heat from the space to be cooled via space cooling units (102,104) and then further absorbs heat from a condenser (120) of the refrigeration unit (114) in a heat exchanger (124). Heat from the space to be cooled and from the refrigeration unit (114) is dissipated to the ambient environment via the evaporative cooling unit (108). The cooling liquid is cooled in the evaporative cooling unit (108) and is recirculated.

Inventors:
SINGHAL, Vishal (H-202, P.F. Housing Indian School of Business, Gachibowli, Hyderabad 1, 500 111, IN)
Application Number:
IB2018/059404
Publication Date:
June 06, 2019
Filing Date:
November 28, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
SINGHAL, Vishal (H-202, P.F. Housing Indian School of Business, Gachibowli, Hyderabad 1, 500 111, IN)
International Classes:
F25B5/00; F24F1/0007; F24F5/00; F25D16/00; F28C1/00; F28C3/08; F28D7/00; F28D7/12; F28F25/02
Foreign References:
GB2455332A2009-06-10
US20050279115A12005-12-22
EP3113591A22017-01-04
US20110289951A12011-12-01
CN205897444U2017-01-18
US20160209852A12016-07-21
Other References:
None
Attorney, Agent or Firm:
LAKSHMIKUMARAN, Malathi et al. (B6/10, Safdarjung Enclave, New Delhi 9, 110029, IN)
Download PDF:
Claims:
I/We Claim

1. A cooling apparatus (100) for cooling a space comprising: an evaporative cooling unit (108) to allow flow of a cooling liquid therein; at least one space cooling unit (102,104) fluidically coupled with the evaporative cooling unit (108) and in a heat exchange configuration with the space; and a first heat exchanger (122) and a second heat exchanger (124) fluidically coupled to the evaporative cooling unit (108) and the at least one space cooling unit (102, 104), wherein the first heat exchanger (122), the second heat exchanger (124), at least one space cooling unit (102,104) and the evaporative cooling unit (108) form a cooling circuit (112) for the cooling liquid; and a refrigeration unit (114) including a refrigerant circuit (116) to allow flow of a refrigerant therein, the refrigerant circuit (116) being fluidically isolated from and in a heat exchange configuration with the cooling circuit (112), wherein the refrigerant circuit (116) and the cooling circuit (112) exchange heat at the first heat exchanger (122) and the second heat exchanger (124).

2. The cooling apparatus (100) as claimed in claim 1, wherein the evaporative cooling unit (108) comprises: at least one inlet channel (601) to receive a cooling stream; at least one outlet channel (602) fluidically coupled to and in a heat exchange configuration with the at least one inlet channel (601) to receive the cooling stream from the at least one inlet channel (601), wherein the at least one outlet channel (602) receives a vaporizing agent; and at least one cooling channel (603) to receive the cooling liquid, wherein the at least one cooling channel (603) is fluidically isolated from the at least one inlet channel (601) and the at least one outlet channel (602), and in the heat exchange configuration with at least one of the at least one inlet channel (601) or the at least one outlet channel (602).

3. The cooling apparatus (100) as claimed in claim 2, wherein a temperature of the cooling liquid exiting from the at least one cooling channel (603) is close to a dew point temperature of the cooling stream in the at least one inlet channel (601).

4. The cooling apparatus (100) as claimed in claim 2, wherein the at least one cooling channel (603) includes an ingress port to allow ingress of the cooling liquid in the at least one cooling channel (603) and an egress port to allow egress of the cooling liquid from the at least one cooling channel (603).

5. The cooling apparatus (100) as claimed in claim 2, wherein the at least one inlet channel (601) includes an inlet port to allow ingress of the cooling stream in the at least one inlet channel (601).

6. The cooling apparatus (100) as claimed in claim 2, wherein the at least one outlet channel (602) includes an outlet port to allow egress of the cooling stream from the at least one outlet channel (602).

7. The cooling apparatus (100) as claimed in claim 2, wherein the at least one outlet channel (602) includes an ingress port to allow ingress of the vaporizing agent in the at least one outlet channel (602) and an egress port to allow egress of the vaporizing agent from the at least one outlet channel (602).

8. The cooling apparatus (100) as claimed in claim 1, wherein the refrigeration unit (114) includes an evaporator (118) to enable transferring heat from the cooling liquid to the refrigerant in the first heat exchanger (122), and a condenser (120) to enable transferring heat from the refrigerant to the cooling liquid in the second heat exchanger (124).

9. The cooling apparatus (100) as claimed in claim 1, wherein the first heat exchanger (122) exchanges heat between the refrigerant and the cooling liquid flowing from the evaporative cooling unit (108) to the space cooling unit (102, 104).

10. The cooling apparatus (100) as claimed in claim 1, wherein the second heat exchanger (124) exchanges heat between the refrigerant and the cooling liquid flowing from the space cooling unit (102,104) to the evaporative cooling unit (108).

11. The cooling apparatus (100) as claimed in claim 1, wherein the second heat exchanger (206) exchanges heat between the refrigerant and a stream of the cooling liquid flowing from the evaporative cooling unit (108) into the second heat exchanger (206).

12. The cooling apparatus (100) as claimed in claim 1, wherein the refrigeration unit (114) is one of a vapour compression refrigeration or a vapour absorption refrigeration or a vapour adsorption refrigeration.

13. The cooling apparatus (100) as claimed in claim 2, wherein the cooling stream is atmospheric air.

14. The cooling apparatus (100) as claimed in claim 2, wherein the vaporizing agent includes water.

15. The cooling apparatus (100) as claimed in claim 1, wherein a plurality of the space cooling unit (102, 104) in parallel receive the cooling liquid.

16. A cooling apparatus (300) for cooling a space comprising: a refrigeration unit (114) including a refrigerant circuit (116) to allow flow of a refrigerant therein; a first evaporative cooling unit (108-1) including a cooling liquid, wherein the first evaporative cooling unit (108-1) is fluidically coupled with at least one space cooling unit (102) and a first heat exchanger (122) to form a first cooling circuit (302), wherein the refrigerant circuit (116) exchanges heat with the first cooling circuit (302) in heat exchanger (122); and a second evaporative cooling unit (108-2) including a cooling liquid, wherein the second evaporative cooling unit (108-2) is fluidically coupled with a second heat exchanger (124) to form a second cooling circuit (304), wherein the refrigerant circuit (116) exchanges heat with the second cooling circuit (304) in heat exchanger (124).

17. The cooling apparatus (300) as claimed in claim 16, wherein each of the first evaporative cooling unit (108-1) and the second evaporative cooling unit (108- 2) comprises: at least one inlet channel (601) to receive a cooling stream; at least one outlet channel (602) fluidically coupled to and in a heat exchange configuration with the at least one inlet channel (601) to receive the cooling stream from the at least one inlet channel (601), wherein the at least one outlet channel (602) receives a vaporizing agent; and at least one cooling channel (603) to receive the cooling liquid, wherein the at least one cooling channel (603) is fluidically isolated from the at least one inlet channel (601) and the at least one outlet channel (602), and in the heat exchange configuration with at least one of the at least one inlet channel (601) or the at least one outlet channel (602).

18. A cooling apparatus (400) for cooling a space comprising; an evaporative cooling unit (108) to allow flow of a refrigerant therein, wherein the refrigerant condenses and dissipates heat in the evaporative cooling unit (108); and at least one space cooling unit (102) fluidically coupled with the evaporative cooling unit (108), wherein the evaporative cooling unit (108) and the space cooling unit (102) form a refrigerant circuit (116) for flow of the refrigerant, wherein the refrigerant evaporates and absorbs heat in the space cooling unit (102).

19. The cooling apparatus (400) as claimed in claim 18, wherein the evaporative cooling unit (108) comprises: at least one inlet channel (601) to receive a cooling stream; at least one outlet channel (602) fluidically coupled to and in a heat exchange configuration with the at least one inlet channel (601) to receive the cooling stream from the at least one inlet channel (601), wherein the at least one outlet channel (602) receives a vaporizing agent; and at least one cooling channel (603) to receive the refrigerant, wherein the at least one cooling channel (603) is fluidically isolated from the at least one inlet channel (601) and the at least one outlet channel (602), and in the heat exchange configuration with at least one of the at least one inlet channel (601) or the at least one outlet channel (602).

AMENDED CLAIMS

received by the International Bureau on 24 April 2019 (24.04.2019)

1. A cooling apparatus (100) for cooling a space comprising: an evaporative cooling unit (108) to allow flow of a cooling liquid therein; at least one space cooling unit (102,104) fluidically coupled with the evaporative cooling unit (108) and in a heat exchange configuration with the space; and a first heat exchanger (122) and a second heat exchanger (124) fluidically coupled to the evaporative cooling unit (108) and the at least one space cooling unit (102, 104), wherein the first heat exchanger (122), the second heat exchanger (124), at least one space cooling unit (102,104) and the evaporative cooling unit (108) form a closed loop cooling circuit (112) for the cooling liquid; and a refrigeration unit (114) including a refrigerant circuit (116) to allow flow of a refrigerant therein, the refrigerant circuit (116) being fluidically isolated from and in a heat exchange configuration with the closed loop cooling circuit (112), wherein the refrigerant circuit (116) and the closed loop cooling circuit (112) exchange heat at the first heat exchanger (122) and the second heat exchanger (124).

2. The cooling apparatus (100) as claimed in claim 1, wherein the evaporative cooling unit (108) comprises: at least one inlet channel (601) to receive a cooling stream; at least one outlet channel (602) fluidically coupled to and in a heat exchange configuration with the at least one inlet channel (601) to receive the cooling stream from the at least one inlet channel (601), wherein the at least one outlet channel (602) receives a vaporizing agent; and at least one cooling channel (603) to receive the cooling liquid, wherein the at least one cooling channel (603) is fluidically isolated from the at least one inlet channel (601) and the at least one outlet channel (602), and in the heat exchange configuration with at least one of the at least one inlet channel (601) or the at least one outlet channel (602).

3. The cooling apparatus (100) as claimed in claim 2, wherein a temperature of the cooling liquid exiting from the at least one cooling channel (603) is close to a dew point temperature of the cooling stream in the at least one inlet channel (601).

4. The cooling apparatus (100) as claimed in claim 2, wherein the at least one cooling channel (603) includes an ingress port to allow ingress of the cooling liquid in the at least one cooling channel (603) and an egress port to allow egress of the cooling liquid from the at least one cooling channel (603).

5. The cooling apparatus (100) as claimed in claim 2, wherein the at least one inlet channel

(601) includes an inlet port to allow ingress of the cooling stream in the at least one inlet channel (601).

6. The cooling apparatus (100) as claimed in claim 2, wherein the at least one outlet channel

(602) includes an outlet port to allow egress of the cooling stream from the at least one outlet channel (602).

7. The cooling apparatus (100) as claimed in claim 2, wherein the at least one outlet channel (602) includes an ingress port to allow ingress of the vaporizing agent in the at least one outlet channel (602) and an egress port to allow egress of the vaporizing agent from the at least one outlet channel (602).

8. The cooling apparatus (100) as claimed in claim 1, wherein the refrigeration unit (114) includes an evaporator ( 118) to enable transferring heat from the cooling liquid to the refrigerant in the first heat exchanger (122), and a condenser (120) to enable transferring heat from the refrigerant to the cooling liquid in the second heat exchanger (124).

9. The cooling apparatus (100) as claimed in claim 1, wherein the first heat exchanger (122) exchanges heat between the refrigerant and the cooling liquid flowing from the evaporative cooling unit (108) to the space cooling unit (102, 104).

10. The cooling apparatus (100) as claimed in claim 1, wherein the second heat exchanger (124) exchanges heat between the refrigerant and the cooling liquid flowing from the space cooling unit (102,104) to the evaporative cooling unit (108).

11. The cooling apparatus (100) as claimed in claim 1, wherein the second heat exchanger (206) exchanges heat between the refrigerant and a stream of the cooling liquid flowing from the evaporative cooling unit (108) into the second heat exchanger (206).

12. The cooling apparatus (100) as claimed in claim 1, wherein the refrigeration unit (114) is one of a vapour compression refrigeration or a vapour absorption refrigeration or a vapour adsorption refrigeration.

13. The cooling apparatus (100) as claimed in claim 2, wherein the cooling stream is atmospheric air.

14. The cooling apparatus (100) as claimed in claim 2, wherein the vaporizing agent includes water.

15. The cooling apparatus (100) as claimed in claim 1, wherein a plurality of the space cooling unit (102,104) in parallel receive the cooling liquid.

16. A cooling apparatus (300) for cooling a space comprising: a refrigeration unit (114) including a refrigerant circuit (116) to allow flow of a refrigerant therein; a first evaporative cooling unit (108-1) including a cooling liquid, wherein the first evaporative cooling unit (108-1) is fluidically coupled with at least one space cooling unit (102) and a first heat exchanger (122) to form a first closed loop cooling circuit (302) to allow the flow of cooling liquid therein, wherein the refrigerant circuit (116) exchanges heat with the first closed loop cooling circuit (302) in heat exchanger (122); and a second evaporative cooling unit (108-2) including a cooling liquid, wherein the second evaporative cooling unit (108-2) is fluidically coupled with a second heat exchanger (124) to form a second closed loop cooling circuit (304) to allow the flow of cooling liquid therein, wherein the refrigerant circuit (116) exchanges heat with the second closed loop cooling circuit (304) in heat exchanger (124).

17. The cooling apparatus (300) as claimed in claim 16, wherein each of the first evaporative cooling unit (108-1) and the second evaporative cooling unit (108-2) comprises: at least one inlet channel (601) to receive a cooling stream; at least one outlet channel (602) fluidically coupled to and in a heat exchange configuration with the at least one inlet channel (601) to receive the cooling stream from the at least one inlet channel (601), wherein the at least one outlet channel (602) receives a vaporizing agent; and at least one cooling channel (603) to receive the cooling liquid, wherein the at least one cooling channel (603) is fluidically isolated from the at least one inlet channel (601) and the at least one outlet channel (602), and in the heat exchange configuration with at least one of the at least one inlet channel (601) or the at least one outlet channel (602).

18. A cooling apparatus (400) for cooling a space comprising; an evaporative cooling unit (108) to allow flow of a refrigerant therein, wherein the refrigerant condenses and dissipates heat in the evaporative cooling unit (108); and at least one space cooling unit ( 102) fluidically coupled with the evaporative cooling unit (108), wherein the evaporative cooling unit ( 108) and the space cooling unit ( 102) form a refrigerant circuit (116) for flow of the refrigerant, wherein the refrigerant evaporates and absorbs heat in the space cooling unit ( 102).

19. The cooling apparatus (400) as claimed in claim 18, wherein the evaporative cooling unit (108) comprises: at least one inlet channel (601) to receive a cooling stream; at least one outlet channel (602) fluidically coupled to and in a heat exchange configuration with the at least one inlet channel (601) to receive the cooling stream from the at least one inlet channel (601), wherein the at least one outlet channel (602) receives a vaporizing agent; and at least one cooling channel (603) to receive the refrigerant, wherein the at least one cooling channel (603) is fluidically isolated from the at least one inlet channel (601) and the at least one outlet channel (602), and in the heat exchange configuration with at least one of the at least one inlet channel (601) or the at least one outlet channel (602)

Description:
COOLING OF LIQUIDS USING PHASE CHANGE

BACKGROUND [0001] The invention relates to a cooling apparatus for cooling a space. Space cooling may be employed to lower temperature of a space to make it habitable.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] The features, aspects, and advantages of the subject matter will be better understood with regard to the following descriptions and accompanying figures. In the figures, the left-most digit of a reference number identifies the figure in which the reference number first appears. Use of the same reference number in different figures indicates similar or identical features and components.

[0003] Fig 1 illustrates a cooling apparatus, in accordance with an example implementation of the present subject matter.

[0004] Fig 2 illustrates another example of the cooling apparatus, in accordance with an example implementation of the present subject matter.

[0005] Fig 3 illustrates yet another example of the cooling apparatus, in accordance with an example implementation of the present subject matter.

[0006] Fig.4 illustrates yet another example of the cooling apparatus, in accordance with an example implementation of the present subject matter.

[0007] Fig.5 illustrates yet another example of the cooling apparatus, in accordance with an example implementation of the present subject matter.

[0008] Fig 6 illustrates a front view of the evaporative cooling unit, in accordance with an example implementation of the present subject matter.

[0009] Fig 7 illustrates a top view of the evaporative cooling unit, in accordance with an example implementation of the present subject matter. [0010] Fig 8 illustrates a bottom view of the evaporative cooling unit, in accordance with an example implementation of the present subject matter.

DETAILED DESCRIPTION

[0011] Various types of systems may be employed for cooling a space. The most commonly used system is a vapour compression refrigeration system. Generally, the vapour compression refrigeration systems may include an evaporator, a condenser and a few other components. Further, a refrigerant flowing through a refrigeration unit absorbs heat at the evaporator and dissipates absorbed heat at the condenser. Typically, smaller sized refrigeration units, such as the ones used at homes for space cooling, directly transfer heat between the refrigerant and the air both at the evaporator and at the condenser. However, large refrigeration units which are used to cool large spaces, such as malls, auditoriums, and large office buildings, commonly use a cooling liquid which act as a heat transfer medium between the refrigerant and the air. The cooling liquid can be used either with the evaporator or with the condenser or with both. Typically, separate cooling liquid circuits are used with the evaporator and with the condenser. Generally, in a cooling liquid circuit including the evaporator the heat is transferred from the air to the cooling liquid, and then from the cooling liquid to the refrigerant. Further, heat exchangers used to transfer heat from the air to the cooling liquid may be called space cooling units. Various types of space cooling units, both with or without fans, may be used. Some common examples include fan coil units and air handling units. The refrigeration units that uses a cooling liquid at the condenser, also uses an evaporative cooler, called a cooling tower, to cool the cooling liquid. Either the cooling liquid is directly cooled in the cooling tower or indirectly in a heat exchanger through a liquid which is cooled in the cooling tower. Else of a cooling tower can increase the energy efficiency of the refrigeration unit.

[0012] The present subject matter relates to a cooling apparatus for cooling a space. According to an example implementation of the present subject matter, the cooling apparatus may include a space cooling unit, and an evaporative cooling unit. Further, the space cooling unit and the evaporative cooling unit may be fluidically connected to form a closed cooling circuit to allow a cooling liquid to flow there through. Furthermore, the cooling liquid circulating in the cooling circuit can facilitate cooling of the space to be cooled. In another example, the cooling liquid may absorb the heat from the space to be cooled through the space cooling unit and may dissipate the absorbed heat to ambient environment through the evaporative cooling unit. Further, the cooling liquid may be recirculated in the cooling circuit. Furthermore, since the cooling liquid flows in a closed loop and is not exposed to the ambient environment, it may not accumulate contaminants.

[0013] According to another example implementation of the present subject matter, the cooling apparatus may also include a refrigeration unit that can have a refrigerant circuit with a refrigerant flowing therein. The refrigeration unit includes an evaporator, a condenser and other components that forms the refrigerant circuit. As the refrigerant flows in the refrigerant circuit, the refrigerant absorbs the heat at the evaporator and dissipates the absorbed heat at the condenser. Further, the cooling circuit and the refrigerant circuit can be in heat exchange configuration with each other. As an example, the cooling liquid moving in the cooling circuit from the evaporative cooling unit to the space cooling unit, can further dissipate heat to the refrigerant flowing in the evaporator of the refrigeration unit through a heat exchanger. This may facilitate in further lowering the temperature of the cooling liquid which may effectively be able to provide a higher degree of cooling to the space to be cooled. The refrigerant can further dissipate the heat back to the cooling liquid, including the heat generated by operation of refrigeration unit, for effective operation of the refrigeration unit. In one example, a heat exchanger may facilitate dissipation of heat back to the cooling liquid as the refrigerant is flowing through the condenser of the refrigeration unit. In one example, heat is absorbed by the cooling liquid moving from the space cooling unit to the evaporative cooling unit. In another example, the cooling circuit may be designed such that the heat is absorbed by a portion of the cooling liquid coming directly from the evaporative cooling unit. [0014] In the cooling apparatus based on the present subject matter, the cooling load may be better distributed between the evaporative cooling unit and the refrigeration unit. Further, all the heat is ultimately discharged to the ambient environment by the evaporative cooling unit. Furthermore, the refrigeration unit may help in lowering the temperature of the cooling liquid to more desirable levels thereby enhancing the cooling ability of the cooling liquid and allowing the cooling liquid to absorb more heat. Furthermore, only a part of the heat from the space to be cooled passes through the refrigeration unit. Rest of the heat can be directly being dissipated to the ambient environment by the evaporative cooling unit. The cooling apparatus based on the present subject matter may provide similar level of cooling but consume less power than refrigeration systems where all the heat from the space to be cooled passes through the refrigeration unit before being discharged to the ambient environment by the evaporative cooling unit. Further, the cooling apparatus based on the present subject matter may provide similar level of cooling but consume less power than refrigeration units which directly transfer heat between the refrigerant and the air either at the evaporator, or at the condenser, or at both.

[0015] The above aspects are further described in conjunction with the figures, and in associated description below. It should be noted that the description and figures merely illustrate principles of the present subject matter. Therefore, various assemblies that encompass the principles of the present subject matter, although not explicitly described or shown herein, may be devised from the description and are included within its scope. Additionally, the word“coupled” is used throughout for clarity of the description and can include either a direct connection or an indirect connection.

[0016] Fig. 1 illustrates a cooling apparatus 100 for cooling a space, in accordance with an implementation of the present subject matter. Further, the cooling apparatus 100 may include plurality of space cooling units 102 and 104 for extracting heat from the space to be cooled. Further, each of the space cooling units 102 and 104 may include a fan 106 for forced circulation of air through the space cooling unit 102 and 104 and the space to be cooled. Although the current implementation illustrates two space cooling units, the cooling apparatus 100 may include a single space cooling unit or multiple space cooling units. Further, the cooling apparatus 100 includes an evaporative cooling unit 108 including a cooling liquid to cool the space. In one example, the evaporative cooling unit 108 may be coupled to the fan 110 to dissipate heat to the ambient environment. Further, the space cooling units 102 and 104 may be connected fluidically to the evaporative cooling unit 108 to form a cooling circuit 112 to allow the cooling liquid to flow therein. Further, the evaporative cooling unit 108 may cool the cooling liquid and pump the cooling liquid towards the space cooling units 102 and 104 where the cooling liquid absorbs heat from the space. Thereafter, the cooling liquid travels back to the evaporative cooling unit 108 where the heat absorbed by the cooling liquid is discharged to the ambient environment.

[0017] In one example, the cooling apparatus 100 may include a refrigeration unit 114 which includes a refrigerant that flows in a refrigerant circuit 116 within the refrigeration unit 114. In an example, the refrigeration unit 114 may include a compressor 126 in case the refrigeration unit 114 is a vapour compression refrigeration unit and may also include an expansion valve 128. In one example, the refrigerant circuit 116 may include an evaporator 118 and a condenser 120 that form parts of the refrigerant circuit 116. Further, the evaporator 118 may be coupled in a first heat exchanger 122 to allow heat exchange between the cooling circuit 112 and the refrigerant circuit 116. Furthermore, the condenser 120 may be coupled in a second heat exchanger 124 to allow heat exchange between the cooling circuit 112 and the refrigerant circuit 116. Further, the heat exchangers 122 and 124 may be fluidically coupled to the evaporative cooling unit 108 and the space cooling units 102 and 104. Furthermore, the heat exchangers 122 and 124, the evaporative cooling unit 108 and the space cooling units 102 and 104 form the cooling circuit 112 with cooling liquid. Further, the refrigerant in evaporator 118 may absorb heat from the cooling liquid coming from the evaporative cooling unit 108 as the cooling liquid travels through the first heat exchanger 122 to the space cooling units 102 and 104. This may further cool the cooling liquid and increase a heat absorbing capacity of the cooling liquid. Further, the condenser 120 may transfer the heat from the refrigerant to the cooling liquid coming from the space cooling units 102 and 104 as the cooling liquid further travels through the heat exchanger 124 to the evaporative cooling unit 108 to dissipate the heat to the ambient environment. It should be noted that other components of the refrigeration unit 114 have not been shown here for the sake of simplicity.

[0018] During operation, the evaporative cooling unit 108 may cool the cooling liquid and pump the cooling liquid into the cooling circuit 112. Also, the refrigeration unit 114 may cool the refrigerant in the refrigerant circuit 116. In one example, the refrigerant may be cooled to a temperature lower than the temperature of the cooling liquid which exits from the evaporative cooling unit 108. As a result, when the cooling liquid is flowing through the first heat exchanger 122 and the refrigerant is flowing through the evaporator 118, the refrigerant may absorb heat from the cooling liquid thereby further reducing temperature of the cooling liquid. Further, the cooling liquid exiting from the first heat exchanger 122 may enter the space cooling units 102, 104 where the cooling liquid absorbs heat from the space thereby cooling the space. Further, the cooling liquid, upon absorbing heat from the space may flow towards the evaporative cooling unit 108 via the second heat exchanger 124 where the condenser 120 may dissipate heat from the refrigerant to the cooling liquid. The cooling liquid exiting from the second heat exchanger 124 may enter the evaporative cooling unit 108 where the cooling liquid is cooled to again absorb heat from the space in the next cycle. Further, the refrigerant exiting the evaporator 118 moves towards the compressor 126 and the condenser 120. Further, the refrigerant exiting the condenser 120 moves towards the expansion valve 128 and the evaporator 118.

[0019] Another example of the cooling apparatus 200, in accordance with one implementation of the present subject matter is shown in Fig. 2. In the illustrated example, some of the components of the cooling apparatus 200 may be similar to the components of the cooling apparatus 100. For example, the space cooling units 102 and 104, and the evaporative cooling unit 108 along with their working principle are similar to that of the cooling apparatus 100. However, the cooling circuit 202 in the cooling apparatus 200 is different from the cooling circuit 112 in the cooling apparatus 100. In the illustrated example, the cooling liquid coming out from the evaporative cooling unit 108 may be split into two streams. Further, one of the streams may flow towards a first heat exchanger 204 while the other stream may flow towards a second heat exchanger 206. Hence, the condenser 120 can dissipate heat to a stream of the cooling liquid coming directly from the evaporative cooling unit 108. After absorbing heat from the condenser 120, the stream of cooling liquid exiting from the second heat exchanger 206 may merge with the stream of cooling liquid coming from the space cooling units 102 and 104 and then may enter the evaporative cooling unit 108.

[0020] Fig. 3 illustrates another example of the cooling apparatus 300 where the evaporative cooling units 108-1 and 108-2 are used in accordance with an example implementation of the present subject matter. The cooling apparatus 300 may include a refrigeration unit 114 similar to the one explained with respect to Fig 1 and therefore may include an evaporator 118 and a condenser 120. In an example the evaporator 118, the condenser 120, the expansion valve 128 and the compressor 126 may form a refrigerant circuit 116, similar to the refrigerant circuit as illustrated in Fig. 1 and 2. The cooling apparatus 300 may also include a first heat exchanger 122 and a second heat exchanger 124 similar to the ones explained with respect to Fig. 1. In one example, the evaporative cooling unit 108-1, the space cooling unit 102 and the heat exchanger 122 may together form a first cooling circuit 302. Further, similar to Fig 1., the evaporative cooling units 108-1 and 108-2 may be coupled to the fans 110 to dissipate heat to the ambient environment. In the illustrated example, the cooling liquid may be cooled by the evaporative cooling unit 108-1 and is further cooled by the evaporator 118 of the refrigeration unit 114 in the first heat exchanger 122. The cooling liquid exiting from the first heat exchanger 122 is sent to space cooling units 102. On the other side of the refrigeration unit 114, the condenser 120 discharges heat from the refrigerant to a cooling liquid in the second heat exchanger 124. In an example, the evaporative cooling unit 108-2 and the heat exchanger 124 may together form a second cooling circuit 304. Further the heat from the cooling liquid is then discharged to the ambient environment using the evaporative cooling unit 108-2.

[0021] Fig. 4 illustrates another example of the cooling apparatus 400 in accordance with an example implementation of the present subject matter. The said implementation may not have a cooling liquid circuit. Further, in the illustrated implementation, the cooling apparatus 400 includes an evaporative cooling unit 108, a space cooling unit 102, a compressor 126 and an expansion valve 128, which together form a refrigerant circuit 116. In the said example, the evaporator of the refrigeration unit 114 may be integrated with the space cooling unit 102 and the condenser 120 of the refrigeration unit 114 may be integrated with the evaporative cooling unit 108. In an example, heat from refrigerant exiting from the compressor 126 may be dissipated to the ambient environment in the evaporative cooling unit 108. Hence, the evaporative cooling unit 108 directly cools the refrigerant, which is a phase-change material. Further, the refrigerant may absorb heat from the space to be cooled in the space cooling unit 102. Refrigeration systems other than vapour compression can also be used.

[0022] Fig. 5 illustrates another example of the cooling apparatus 500 in accordance with an example implementation of the present subject matter. The said implementation may not have a separate refrigeration unit. Further, in the illustrated implementation, the cooling apparatus 500 includes an evaporative cooling unit 108 which is fluidically coupled with at least one space cooling units 102 and 104 and which together form a cooling liquid circuit 502. Here, the cooling liquid exiting from the evaporative cooling unit 108 can be used directly for space cooling in the space cooling units 102 and 104. Further, the space cooling units 102 and 104 can directly send the cooling liquid back to the evaporative cooling unit 108. The abovementioned embodiment can be used in scenarios where the evaporative cooling unit 108 may be able to lower the temperature of the cooling liquid to a level such that the evaporative cooling unit 108 can solely cool the cooling space. [0023] Although the evaporative cooling unit 108 can of any type or design, an example of the evaporative cooling unit 108 based on the present subject matter is explained with respect to Fig. 6 to 8.

[0024] Fig. 6, Fig. 7 and Fig. 8 illustrate an example implementation of the evaporative cooling unit 108. Specifically, Fig.6 illustrates a front view, Fig.7 illustrates a top view and Fig.8 illustrates a bottom view of the evaporative cooling unit. Fig. 6 illustrates at least one cooling channel 603, more than one inlet channels

601-1 and 601-2 and more than one outlet channels 602-1, 602-2, 602-3 and 602- 4, in accordance with one implementation of the present subject matter. The inlet channels 601-1, 601-2, are collectively referred to as 601 and the outlet channels

602-1, 602-2, 602-3 and 602-4 are collectively referred to as 602. In one example, the cooling channels 603 may be adjacent to one or more outlet channels 602. In one example, the inlet channels 601 may be adjacent to one or more outlet channels 602. In one embodiment, the inlet channels 601, the outlet channels 602 and the cooling channel 603 are in heat exchange configuration with their respective adjacent channels. In one embodiment, the inlet channels 601 are adapted to receive a cooling stream. In an example, the inlet channels 601 are fluidically coupled to the outlet channels 602. The outlet channels 602, for example, may receive the cooling stream from the inlet channels 601. In one example, the outlet channels 602 are adapted to receive a vaporizing agent. In one example, the cooling channels 603 are adapted to receive the cooling liquid. According to an aspect, the vaporizing agent in outlet channels 602 may absorb heat and evaporate, cooling the surroundings so that the outlet channels 602 may absorb heat from the adjacent inlet channels 601 and the cooling channels 603. This may cool the cooling stream in inlet channels 601 and the cooling liquid in the cooling channels 603 to a temperature close to the dew point temperature of the cooling stream in inlet channels 601. In one example, temperature of the cooling stream received by the outlet channels 602 is close to the dew point temperature. In another example, temperature of the cooling liquid exiting the cooling channels 603 is close to the dew point temperature of the cooling stream in inlet channels 601. [0025] According to an example, only a part of the vaporizing agent may be converted into vapour and the cooling stream may carry the vaporized part from the outlet channels 602. In another example, all of the vaporizing agent may be converted into vapour and all the vapours may be carried by the cooling stream. In another example, only one or more or all components of the vaporizing agent may be converted into vapour and the cooling stream carries the vaporized components from the outlet channels 602. In one example, the vaporizing agent may include water. In one example, the cooling liquid may include water. In another example, cooling liquid may be a phase-change material such as a refrigerant. In one example, the cooling stream may be atmospheric air.

[0026] In one aspect, each of the cooling channels 603 may include an inlet to allow ingress of cooling liquid and an outlet to allow egress of cooling liquid. Further, the inlets of each of the cooling channels 603 may be connected to a single primary inlet channel (not shown in Fig.) to allow ingress of the cooling liquid in each of the cooling channels 603. In one embodiment, inlets of some or all of the cooling channels 603 may be isolated from one another. Also, the outlets of each of the cooling channels 603 may be connected to a single primary outlet channel (not shown in Fig.) to allow egress of the cooling liquid from each of the cooling channels 603. In one embodiment, outlets of some or all of cooling channels 603 may be isolated from one another. In one example, each of the inlet channels 601 may include an inlet to allow ingress of cooling stream. Further, the inlets of each of the inlet channels 601 may be connected to a single primary inlet (not shown in Fig.) to allow ingress of the cooling stream in each of the inlet channels 601. In one embodiment, inlets of some or all of the inlet channels 601 may be isolated from one another. In one example, each of the outlet channels 602 may include an outlet to allow egress of cooling stream. Further, the cooling stream outlets of each of the outlet channels 602 may be connected to a single primary cooling stream outlet (not shown in Fig.) to allow egress of the cooling stream from each of the outlet channels 602. In one embodiment, the cooling stream outlets of some or all of the outlet channels 602 may be isolated from one another. In one aspect, each of the outlet channels 602 may include an inlet to allow ingress of vaporizing agent and an outlet to allow egress of vaporizing agent. Further, the vaporizing agent inlets of each of the outlet channels 602 may be connected to a single primary inlet (not shown in Fig.) to allow ingress of the vaporizing agent in each of the outlet channels 602. In one embodiment, the vaporizing agent inlets of some or all of the outlet channels 602 may be isolated from one another. Also, the vaporizing agent outlets of each of the outlet channels 602 may be connected to a single primary outlet (not shown in Fig.) to allow egress of the vaporizing agent from each of the outlet channels 602. In one embodiment, the vaporizing agent outlets of some or all of outlet channels 602 may be isolated from one another.

[0027] In the example implementation shown in Fig. 6, the cooling channels 603, inlet channels 601 and outlet channels 602 are formed by straight parallel plates. However, non-straight and/or non-parallel plates can also be used. Also, other geometries such as a honeycomb structure and its variations can also be used to form the cooling channels 603, inlet channels 601 and outlet channels 602. Further, other kinds of heat exchangers such as shell and tube heat exchangers can also be used in the evaporative cooling unit 108. Further, combinations of different heat exchanger designs can also be used in the evaporative cooling unit 108. In one example, flow of the cooling liquid in the cooling channels 603, and/or flow of the cooling stream in the inlet channels 601 and/or in the outlet channels 602 may be in a zig zag arrangement to increase the effective length of the cooling channels 603, inlet channels 601, and outlet channels 602. In one example, the evaporative cooling unit 108 is able to cool the cooling liquid to temperatures lower than the wet bulb temperature and up to a dew point temperature of cooling stream in the inlet channels 601.

[0028] In one example, the cooling liquid can also flow in pipes and/or in tubes. These pipes/tubes can lie either on the walls between the outlet channels (for example 602-2 and 602-3), or they can lie partly or completely in one of the outlet channels 602. In this example, adjacent outlet channels can also merge (for example, wall between outlet channels 602-2 and 602-3 can disappear), such that only a single outlet channel remains instead of outlet channels 602-2 and 602-3. Further, pipes/tubes with the cooling liquid need not be restrained to the outlet channels 602. They can traverse in inlet channels 601 as well. They can also traverse in multiple inlet channels 601 and multiple outlet channels 602. In one example, the flow of cooling liquid in channels/pipes/tubes can either be along the full length of the inlet channels and outlet channels, or it can be along only a part length of the inlet channels and outlet channels.

[0029] The operation of the evaporative cooling unit 108 will now be described. In an example, the cooling stream may be atmospheric air. In one example, the vaporizing agent may include water. The inlet channels 601 receive the cooling stream and the cooling channels 603 receive the cooling liquid. The vaporizing agent is introduced in the outlet channels 602. As the cooling stream enters the outlet channels 602 from the inlet channels 601, further evaporation of the vaporizing agent happens. The latent heat transfer associated with the evaporation causes a drop in the temperature of the outlet channels 602. Since the cooling channels 603 and the inlet channels 601 are in a heat-exchange configuration with the outlet channels 602, heat is transferred from the cooling liquid passing through the cooling channels 603 and from the cooling stream passing through the inlet channels 601, to the cooling stream passing through the outlet channels 602. This leads to a drop in temperature of the cooling liquid in the cooling channels 603 and the cooling stream in the inlet channels 601. Since the cooling stream exiting the inlet channels 601 enters the outlet channels 602, temperature of the cooling stream entering the outlet channels 602 also goes down. Further evaporation of the vaporizing agent causes further latent heat transfer which causes a further drop in temperature of the cooling liquid in the cooling channels 603 and of the cooling stream in the inlet channels 601, which causes a further drop in temperature of the cooling stream entering the outlet channels 602. This cycle of evaporation of the vaporizing agent, drop in temperature of the cooling stream in the inlet channels 601 and hence a drop in temperature of the cooling stream entering outlet channels 602 can continue till the temperature of the cooling stream entering the outlet channels 602 reaches a dew point temperature of the cooling stream. When the temperature of the cooling stream is at the dew point temperature, evaporation of the vaporizing agent does not happen anymore. Thus, the cycle of lowering of temperatures of the cooling stream in inlet channels 601 and the cooling liquid in the cooling channels 603 may be stopped. In one example, the cooling liquid in the cooling channels 603 may be cooled to a temperature close to the dew point temperature of the cooling stream in inlet channels 601. Simultaneously, the cooling stream in the inlet channels 601 may also be cooled to a temperature close to the dew point temperature. In one example, vapours of the vaporizing agent may be carried by the cooling stream in the outlet channels 602. In one example, the cooling liquid may be cooled gradually after the flow of cooling stream and vaporizing agent starts.

[0030] Fig. 7 illustrates a top view of the evaporative cooling unit 108 in accordance with an example implementation of the present subject matter. Further, the top view of the evaporative cooling unit 108 can be seen from viewing plane line A-A in Figure 6. Further inlet channels 601-1 and 601-2, outlet channels 602- 1, 602-2, 602-3 and 602-4, and cooling channel 603 are shown in Fig. 7.

Moreover, shaded portions of the inlet channels 601-1 and 601-2 and outlet channels 602-1, 602-2, 602-3 and 602-4 are closed to any flow. Therefore, with reference to Fig. 7, cooling stream flows into the evaporative cooling unit 108 and into the inlet channels 601-1 and 601-2 (and into the plane), from the top part, and flows out of the evaporative cooling unit 108 and out of the outlet channels 602-1, 602-2, 602-3 and 602-4 (and out of the plane) from the bottom part. Moreover, cooling liquid flows into the evaporative cooling unit 108 and into the cooling channel 603 (and into the plane).

[0031] Fig. 8 illustrates a bottom view of the evaporative cooling unit 108, in accordance with an example implementation of the present subject matter. Further, the bottom view of the evaporative cooling unit 108 can be seen from viewing plane line B-B in Fig. 7. With reference to Figure 8, all the inlet channels 601-1 and 601-2 and all the outlet channels 602-1, 602-2, 602-3 and 602-4are shaded indicating that they are closed to flow. Further, the cooling liquid flows out of the cooling channel 603 and out of evaporative cooling unit 108 (and out of the plane). [0032] Although aspects for methods and systems for space cooling apparatus in the document have been described in a language specific to structural features and/or methods, the invention is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples for the space cooling apparatus.