GB2623546A

GB2623546A - Cooling apparatus, system and method of manufacture

Info

Publication number: GB2623546A
Application number: GB2215445.4A
Authority: GB
Inventors: Velayutham Karthikeyan
Original assignee: Katrick Technologies Ltd
Current assignee: Katrick Technologies Ltd
Priority date: 2022-10-19
Filing date: 2022-10-19
Publication date: 2024-04-24
Also published as: GB202215445D0

Abstract

A cooling apparatus 16 for cooling a body 17, such as a data centre (2, Fig.1) with computer systems (4, Fig.1), comprises a first liquid 21 located within a housing 18. Heat from the body evaporates a quantity of the first liquid to form a first liquid vapour in the form of gaseous bubbles 23. The gaseous bubbles transport heat away from the body to the housing by thermal convection. On dissipating energy to the housing, each gaseous bubble 23 condenses to form a liquid bubble 24 of the first liquid and may circulate back towards the body. Alternatively, one or more return pipes (29a, 29b, 29c, Fig.8) may siphon off the liquid bubbles 24 and return them to the base end 20 of the housing. The cooling apparatus may comprise a second liquid 25, the first liquid having a higher density and lower boiling point than the second liquid. The body may be fully or partially immersed within the first liquid or may be located external to the cooling apparatus. The housing may comprise two or more chambers (37, 38, Fig.5) which may be fluidly connected via pipes (39, Fig.5) or via heat exchanging apparatus (42, Fig.6).

Description

1 Cooling Apparatus, System and Method of Manufacture 3 The present invention relates to a cooling apparatus, system and method of manufacture.

4 In particular, the described cooling apparatus is suitable for reducing the temperature of an environment which normally employs air conditioning apparatus e.g. a data centre.

7 Background to the Invention

9 A vapour-compression refrigeration system comprises a working fluid which undergoes repeated phase transitions cycling between a liquid and a gas. This type of refrigeration 11 system has numerous applications, ranging from domestic fridges and freezers to air 12 conditioning systems for buildings.

14 Figure 1 depicts a vapour-compression refrigeration system 1 known in the art used to cool a data centre 2. The data centre 2 takes the form of a building 3 housing computer 16 systems 4. The temperature within the building 3 is often raised above ambient 17 temperature to, for example, 50 °C due to the operation of the computer systems 4. The 18 purpose of the vapour-compression refrigeration system 1 is to lower the temperature 19 within the building 3 such that the computer systems 4 do not overheat.

2 High temperature (50 °C) air 5 within the building 3 is drawn into circulation loop 6, by 3 means of a circulation fan 7. Whilst traversing the circulation loop 6, the high temperature 4 air 5 passes through an evaporator 8 and loses heat. The resulting low temperature air 9 with a temperature of 25°C is pumped into the building 3.

7 The evaporator 8 is part of a sealed refrigeration loop 10 which contains a working fluid 11, 8 commonly known as a refrigerant. The evaporator 8 transfers heat from the high 9 temperature air 5 to the working fluid 11. As such, the evaporator 8 can more generally be considered a heat exchanging apparatus. The heat induces a phase change in the 11 working fluid 11 from a liquid to a gas. The gaseous working fluid 11 circulates about the 12 refrigeration loop 10 where it is then compressed by a compressor 12 resulting in a 13 temperature increase of the gaseous working fluid 11 up to, for example, 65 °C. The hot 14 (65 °C) compressed working fluid 11 is then cooled in a condenser 13 such that the gaseous working fluid 11 expels heat and condenses back to a liquid, resulting in a liquid 16 compressed working fluid 11 with a reduced temperature of, for example, 35°C. After 17 which, the temperature of the liquid working fluid 11 is reduced further to, for example, 18 -30 °C by reducing the pressure of the liquid compressed working fluid 11 by means of an 19 expansion valve 14. The cold (-30 °C) uncompressed working fluid is recirculated into the evaporator where, by means of thermal diffusion, heat again transfers from the high 21 temperature airs to the working fluid 11. The cycle repeats continually cooling the high 22 temperature air 5 originating from the building 3.

24 The vapour-compression refrigeration system 1 as depicted in Figure 1 requires electrical power to operate. In particular, the circulating fan 7, compressor 12 and condenser 13 all 26 draw electrical power. Disadvantageously, such systems 1 can draw significant amounts 27 of electrical power. A relatively large data centre can equate to electrical power 28 requirements equivalent to a town. Such a large electrical power consumption is 29 expensive and also has a significant environmental impact.

31 Another disadvantage of the vapour-compressed refrigeration system 1 is that all the 32 components, in particular the circulating fan 7, compressor 12 and condenser 13, require 33 maintenance. This is an additional financial burden and the vapour-compressed 34 refrigeration system 1 cannot operate during the required maintenance breaks.

1 UK patent application number GB2105589.2 discloses an alternative cooling apparatus 2 where the heat from a body is converted into kinetic energy and dissipated to the 3 surroundings by a combination of thermal convection and kinetic energy transfer via a 4 plurality of independent vibrating rods.

6 Summary of the Invention

8 It is an object of an embodiment of the present invention to provide a cooling system that 9 obviates or at least mitigates one or more of the aforesaid disadvantages of the cooling systems known in the art.

12 It is a further object of an embodiment of the present invention to provide a cooling system 13 that converts heat from a body into kinetic energy and dissipates this kinetic energy into 14 the surroundings by a combination of thermal convection and thermal conduction.

16 According to a first aspect of the present invention there is provided a cooling apparatus 17 suitable for cooling a body, the cooling apparatus comprises: 18 a housing; and 19 a first liquid located within the housing; wherein, in operation, 21 heat from the body evaporates a quantity of the first liquid to form a first liquid 22 vapour; 23 the first liquid vapour transports the heat away from the body to the housing by 24 thermal convection; and the heat dissipates to a surrounding environment via thermal conduction through the 26 housing.

28 In the present invention heat is only transferred to the surrounding environment via thermal 29 convection provided by the first liquid and thermal conduction through the housing i.e. there is no kinetic energy transfer mechanism employed to transfer heat through the 31 housing to the surrounding environment.

33 Preferably, the first liquid occupies an interior volume of the housing.

1 Most preferably, the first liquid is 1-Chloro-3,3,3-trifluoropropene (R1233ZD); or 2 Dichlorotrifluoroethane; or 1,2-Dichlorotetrafluoroethane; or 1,1.1.3.3,3- 3 Hexafluoropropane; or 2,3,3,3-tetrafluoropropene (R1234 YE); or Trans-1,3,3,3- 4 tetrafluoroprop-1-ene (R-1234ze); 1,1,1,3,3-Pentafluoropropane (R245fa); or (Z)-1-Chloro- 2,3,3,3-Tetrafluoropropane (R1224yd(Z)); or trans-1,1,1,4,4,4-hexafluoro-2-butene 6 (R1336mzzE); or de-mineralised water.

8 Additionally, the cooling apparatus may comprise a second liquid. Preferably the first 9 liquid has a higher density and lower boiling point than the second liquid. The first and second liquids may occupy an interior volume of the housing. The first and second liquids ii may mix within the interior volume of the housing.

13 Preferably, the first liquid may be located within a first portion of the housing. The second 14 liquid may be located within a second portion of the housing.

16 Most preferably, the first liquid is 1-Chloro-3,3,3-trifluoropropene (R1233ZD) and the 17 second liquid is de-mineralised water. Alternatively, the first liquid is 18 Dichlorotrifluoroethane and the second liquid is de-mineralised water. Alternatively, the 19 first liquid is 1,2-Dichlorotetrafluoroethane and the second liquid is de-mineralised water.

Alternatively, the first liquid is 1,1,1,3,3,3-Hexafluoropropane and the second liquid is de- 21 mineralised water. Alternatively, the first liquid is 2,3,3,3-Tetrafluoropropene (R1234 YE) 22 and the second liquid is de-mineralised water. Alternatively, the first liquid is R-1234ze 23 (Trans-1,3,3,3-tetrafluoroprop-1-ene) and the second liquid is de-mineralised water.

24 Alternatively, the first liquid is (Z)-1-Chloro-2,3,3,3-Tetrafluoropropane (R1224yd(Z)) and the second liquid is de-mineralised water. Alternatively, the first liquid is trans-1,1,1,4,4,4- 26 hexafluoro-2-butene (R1336mzzE) and the second liquid is de-mineralised water.

28 Additionally, the cooling apparatus may further comprise one or more fluids. Optionally, 29 the one or more fluids may comprise a third liquid.

31 Optionally, the cooling apparatus may comprise a condensing apparatus. The condensing 32 apparatus may be located at a top end of the housing. The condensing apparatus may be 33 suitable for condensing the first liquid vapour.

1 Optionally, the cooling apparatus may further comprise one or more return pipes. The one 2 or more return pipes may be external or internal. The one or more return pipes transfer 3 the first liquid from the condensing apparatus to a base end of the housing. Additionally, 4 or alternatively, the one or more return pipes transfer the first liquid from the housing in the region of the first liquid level to a base end of the housing. Additionally, or alternatively, 6 the one or more return pipes transfer the first liquid from the housing in the region of the 7 second liquid level to a base end of the housing.

9 Preferably, one or more return pipes may comprise one or more heat exchangers. The one or more heat exchangers may be a plurality of channels connected in parallel in a 11 radiator-like structure.

13 Preferably, the housing may comprise a unitary chamber. Alternatively, the housing may 14 comprise two or more chambers.

16 Preferably, the two or more chambers may be fluidly connected by one or more pipes.

17 The cooling apparatus may comprise a pump to circulate the first liquid vapour, first liquid 18 and or second liquid along the one or more pipes between the two or more chambers.

Alternatively, the two or more chambers may be fluidly isolated and thermally connected 21 by a heat exchanging apparatus which transfers heat between the two or more chambers.

23 The heat exchanging apparatus may comprise one or more coil pipes.

Preferably, the housing may be sealable. The cooling apparatus may be a closed cooling 26 apparatus. In this arrangement the liquid(s) are not added and or removed during 27 operation.

29 Preferably, the housing may comprise an inlet port and an outlet port. The inlet and outlet ports are preferably sealable.

32 Optionally, the cooling apparatus further may comprise a sink. The sink may comprise the 33 first liquid. The sink is preferably connected to the housing. The sink maintains the first 34 liquid level within the housing.

1 Optionally, the cooling apparatus may further comprise a pumping system. The pumping 2 system pumps the liquid(s) into and out of the housing.

4 Optionally, the cooling apparatus may further comprise one or more storage tanks. The one or more storage tanks are connected to the pumping system.

7 Optionally, the cooling apparatus may further comprise a circulation loop. The circulation 8 loop may transfer heat external to the housing, to within the housing of the cooling 9 apparatus. The circulation loop may comprise a first heat exchanging apparatus external to the housing and a second heat exchanging apparatus within the housing.

12 According to a second aspect of the present invention there is provided a cooling system 13 comprising a cooling apparatus in accordance with the first aspect of the present invention, 14 and a body to be cooled.

16 Preferably, the body to be cooled may be located within the cooling apparatus. The body 17 to be cooled may be located within the housing. The body to be cooled may be at least 18 partially immersed within the first liquid.

Alternatively, the body to be cooled may be located external to the cooling apparatus. The 21 body to be cooled may be located external to the housing.

23 Embodiments of the second aspect of the invention may comprise features to implement 24 the preferred or optional features of the first aspect of the invention or vice versa.

26 According to a third aspect of the present invention there is provided a method of 27 manufacturing a cooling apparatus suitable for cooling a body, the method comprising, 28 * providing a housing; and 29 * providing a first liquid located within the housing; * wherein, in operation, 31 * heat from the body evaporates a quantity of the first liquid to form a first liquid 32 vapour; 33 * the first liquid vapour transports the heat away from the body to the housing by 34 thermal convection; and 1 * the heat dissipates to a surrounding environment via thermal conduction through 2 the housing.

4 Preferably, the method of manufacturing a cooling apparatus may further comprise determining the characteristics of the body to be cooled by the cooling apparatus.

7 Preferably, determining the characteristics of the body may comprise determining the 8 temperature of the body without any cooling, a target temperature of the body with cooling, 9 the temperature variability of the body, the dimensions, shape and composition.

11 Preferably, the method of manufacturing a cooling apparatus may further comprise 12 determining optimum parameters of a cooling apparatus for use with the body.

14 Preferably, determining the optimum parameters of a cooling apparatus for use with the body may further comprise utilising the characteristics of the body.

17 Preferably, determining the optimum parameters of a cooling apparatus may comprise 18 determining: the dimensions and shape of the cooling apparatus; chemical composition of 19 the first liquid; if a second liquid is required and if so, the volume, relative ratio and chemical composition of the first and second liquids; if a condensing apparatus 28 is 21 required and if so, the configuration of the condensing apparatus 28; if one or more return 22 pipes are required and if so, the configuration of the one or more return pipes; if a sink is 23 required; if storage tanks are required; if a heat exchanging apparatus is required; and the 24 location of the body.

26 Embodiments of the third aspect of the invention may comprise features to implement the 27 preferred or optional features of the first and or second aspect of the invention or vice 28 versa.

According to a fourth aspect of the present invention there is provided a method of 31 manufacturing a cooling system comprising, 32 * providing a cooling apparatus in accordance with the third aspect of the present 33 invention; and 34 * providing a body to be cooled.

1 Optionally providing a body to be cooled comprises immersing or partially immersing the 2 body within the first liquid.

4 Embodiments of the fourth aspect of the invention may comprise features to implement the preferred or optional features of the first, second and or third aspects of the invention or 6 vice versa.

8 According to a fifth aspect of the present invention there is provided a method of operating 9 a cooling system suitable for cooling a body, the method comprising, * transferring heat from the body to evaporate a quantity of a first liquid located 11 within a housing, to form a first liquid vapour; 12 * the first liquid vapour transporting the heat away from the body to the housing by 13 thermal convection; and 14 * dissipating the heat to a surrounding environment via the thermal conduction through the housing.

17 Embodiments of the fifth aspect of the invention may comprise features to implement the 18 preferred or optional features of the first, second third and or fourth aspects of the 19 invention or vice versa.

21 According to a sixth aspect of the present invention there is provided use of a cooling 22 apparatus in accordance with the first aspect of the present invention and or use of a 23 cooling system in accordance with the second aspect of the present invention and or use 24 of a method of operating a cooling system in accordance with the fifth aspect of the present invention to cool a body.

27 Embodiments of the sixth aspect of the invention may comprise features to implement the 28 preferred or optional features of the first, second, third, fourth and or fifth aspects of the 29 invention or vice versa.

1 Brief Descriotion of Drawinds 3 There will now be described, by way of example only, various embodiments of the 4 invention with reference to the drawings, of which: 6 Figure 1 presents a schematic representation of a cooling system known in the art; 8 Figure 2 presents a schematic cross-sectional view of a cooling system in accordance with 9 an embodiment of the present invention; 11 Figure 3 presents a schematic cross-sectional view of an alternative embodiment of the 12 cooling apparatus of Figure 2; 14 Figure 4 presents a schematic cross-sectional view of a component of the cooling system of Figure 3; 17 Figure 5 presents a schematic cross-sectional view of an alternative embodiment of the 18 cooling apparatus of Figure 2; Figure 6 presents a schematic cross-sectional view of an alternative embodiment of the 21 cooling apparatus of Figure 2; 23 Figure 7 presents a schematic cross-sectional view of an alternative embodiment of the 24 cooling apparatus of Figure 2; 26 Figure 8 presents a schematic cross-sectional view of an alternative embodiment of the 27 cooling apparatus of Figure 2; 29 Figure 9 presents a schematic cross-sectional view of an alternative embodiment of the cooling apparatus of Figure 2; 32 Figure 10 presents a schematic cross-sectional view of an alternative embodiment of the 33 cooling apparatus of Figure 2; and 1 Figure 11 presents a flow chart of the method of manufacturing the cooling apparatus of 2 Figure 2.

4 In the description which follows, like parts are marked throughout the specification and drawings with the same reference numerals. The drawings are not necessarily to scale 6 and the proportions of certain parts have been exaggerated to better illustrate details and 7 features of embodiments of the invention.

9 Detailed Description of the Preferred Embodiments 11 An explanation of the present invention will now be described with reference to Figures 2 12 to 11.

14 Cooling System 16 Figure 2 depicts a cooling system 15a comprising a cooling apparatus 16 and a body 17 to 17 be cooled. The body 17 takes the form of a data centre 2 and, specifically, computer 18 systems 4.

The cooling apparatus 16 comprises a substantially cylindrical, sealable housing 18 with a 21 top end 19 and an opposing base end 20. The housing 18 comprises stainless steel, 22 specifically, SASS GR.65. For ease of understanding, Figures 2 depicts a cylindrical 23 coordinate system with r, 0, and z axes.

The cooling apparatus 16 comprises a first liquid 21 located within the housing 18. The 26 liquid 21 occupies an interior volume 22 of the housing 18.

28 By way of example, the first liquid 21 may be trans-1-choloro-3,3,3-trifluoroprop-1-ene 29 (R1233ZD), also referred to as trans chloro trifluoropropene. R1233ZD has a boiling point of 18.3 °C. A cooling apparatus 16 comprising R1233ZD as the first liquid 21 is suitable 31 for cooling a data centre 2 with a temperature over 19 °C. For the cooling apparatus 16 to 32 operate, the first liquid 21 is preferably in liquid form at ambient temperature. As such, the 33 ambient temperature of the environment surrounding the cooling apparatus 16 should be 34 below the boiling point of the first liquid 21 in this case, below 18.3 °C.

1 Further examples of first liquids 21 are provided in Table I along with an operating 2 temperature range of a cooling apparatus 16 comprising each of the first liquids 21.

3 Different first liquids 21 may be suited to different operational temperature ranges and 4 system configurations. It will be appreciated that different operating temperature ranges to those detailed in Table I could be achieved by using different first liquids 21 beyond the 6 disclosed liquids in Table I. 8 Table I: Examples of: the first liquid; and a temperature range of the uncooled body to be 9 cooled by a cooling apparatus comprising the liquid.

First Liquid Operating Temperature Range (0C) De-mineralised water Over 100 °C 1-Chloro-3,3,3-trifluoropropene (Trans Over 19 °C chloro trifluoropropene) R1233ZD (Boiling point: 18.3 °C) Dichlorotrifluoroethane Over 28 °C (Boiling point: 27.6 °C) 1,2-Dichlorotetrafluoroethane Over 4°C (Boiling point: 3.5 °C) 1,1,1,3,3,3-Hexafluoropropane Over 0°C (Boiling point: -1.7 °C) 2,3,3,3-tetrafluoropropene (R1234 YF) Over -20 °C (Boiling point: -29.29 °C) R-1234ze -(Trans-1,3,3,3- Over -18°C tetrafluoroprop-1-ene) (Boiling point: -18.89 °C) 1,1,1,3,3-Pentafluoropropane (R245fa) Over 15 00 (Boiling point: 15 °C) trans-1,1,1,4,4,4-hexafluoro-2-butene Over 7.5°C (HF0-1336mzz-E[70]) (Boiling point: 7.5 00) (Z)-1-Chloro-2,3,3,3-Tetrafluoropropane Over 15 °C R1224yd(Z) (Boiling point: 15 oC) 1 As can be seen from Figure 2, the body 17 to be cooled is located within the cooling 2 apparatus 16. More specifically, the body 17 is located within the housing 18 immersed 3 within the first liquid 21. As such, the cooling apparatus 16 of Figure 2 could be 4 considered an immersion cooling apparatus 16. Nevertheless, it will be appreciated with reference to Figure 10 that the body 17 is not limited to being located within the housing 6 18, immersed within the first liquid 21.

8 In operation, in other words when the cooling apparatus 16 is cooling the body 17, heat 9 from the body 17 evaporates a quantity of the first liquid 21 to form a first liquid vapour.

The first liquid vapour takes the form of gaseous bubbles 23. The gaseous bubbles 23 11 have a lower density than both the first liquid 21 and so move against gravity, in the 12 positive z-direction towards the top end 19 of the housing 18.

14 As will be understood by the skilled reader, evaporating a quantity of the first liquid 21, causes the body 17 to cool since heat from the body 17 is converted into kinetic energy in 16 the form of the motion of the gaseous bubbles 23. In other words, thermal energy from the 17 body 17 is transferred to the gaseous bubbles 23. A key feature of the present invention is 18 that the heat absorbed by the gaseous bubbles 23 is transported away from the body 17 19 by the motion of the gaseous bubbles 23 i.e. the gaseous bubbles 23 provide a means for thermal convection of the thermal energy of the body 17.

22 The gaseous bubbles 23 dissipate kinetic energy to the housing 18. As such, each 23 gaseous bubble 23 will condense to form a liquid bubble 24 of the first liquid 21. The liquid 24 bubbles 24 sink back towards the base end 20 of the housing 18 due to gravity. In other words, the cold condensed liquid bubbles 24 circulate towards the base end 20 of the 26 housing 18 due to thermal convection. The liquid bubbles 24 are circulated back towards 27 the body 17 and so can absorb further heat from the body 17. The housing 18 dissipates 28 heat to the surrounding environment of the cooling apparatus 16 by means of thermal 29 conduction.

31 In summary, the process of absorbing heat from the body 17, transferring the heat within 32 the cooling apparatus 16 from the body 17 to the housing 18 by thermal convection and 33 dissipating the heat from the housing 18 to the surrounding environment of the cooling 34 apparatus 16 by means of thermal conduction is repeated resulting in the continual cooling the body 17.

2 Furthermore, another key feature of the present invention is that in order to keep the body 3 17 at a constant temperature or even reduce the temperature of the body 17, the cooling 4 process is preferably sufficiently quick. More specifically, the velocity of the gaseous bubbles 23 is preferably sufficiently large to relatively quickly transport heat to the top end 6 19 of the housing 18 and cold condensed first liquid 21 relatively quickly replaces the 7 gaseous bubbles 23 about the body 17 so the cooling process can continue.

9 A key advantage of the cooling system 15a is that it requires no electrical energy to operate as does not comprise a circulating fan, compressor, or a condenser. As such, the 11 cooling system 15a is more environmentally friendly than systems known in the art. The 12 cooling apparatus 16 may be considered a passive component as does not require any 13 electrical energy.

As an alternative embodiment, instead of being cylindrical, it will be appreciated that the 16 housing 18 could take any regular or non-regular three-dimensional shape.

18 Figure 3 depicts an alternative cooling system 15b which may comprise the same 19 preferable and optional features as the cooling system 15a depicted in Figure 2.

21 The cooling apparatus 16 depicted in Figure 3 can be seen to further comprise a first liquid 22 21 and a second liquid 25 both of which are located within the housing 18. The first and 23 second liquids 21, 25 both occupy an interior volume 22 of the housing 18. The first liquid 24 21 has a higher density but lower boiling point in comparison to the second liquid 25. As such, whilst the first and second liquids 21, 25 are free to mix within the housing 18, the 26 first liquid 21 locates within a first portion 26 of the housing 18, towards the base end 20 of 27 the housing 18, and the second liquid 25 locates within a second portion 27 of the housing 28 18, above the first liquid 21.

By way of example, the first liquid 21 may be trans-1-choloro-3,3,3-trifluoroprop-1-ene 31 (R1233ZD), also referred to as trans chloro trifluoropropene, and the second liquid 25 may 32 be de-mineralised water. The density of R1233ZD is approximately 1.3 times that of de- 33 mineralised water and R1233ZD has a boiling point of 18.3°C which is lower than the 34 boiling point of demineralised water, 100 °C. A cooling apparatus 16 comprising R12337D and de-mineralised water as the first and second liquids 21, 25 is suitable for cooling a 1 body 17 with a temperature over 19 °C. For the cooling apparatus 16 to operate, both the 2 first and second liquids 21, 25 are required to be in liquid form at ambient temperature. As 3 such, the ambient temperature of the environment surrounding the cooling apparatus 16 4 should be below the boiling point of the first and second liquids 21, 25, in this case, below 18.3°C.

7 Further examples of the first and second liquids 21, 25 are provided in Table I along with 8 an operating temperature range of a cooling apparatus 16 comprising the first and second 9 liquids 21, 25. The combinations of the first and second liquids 21, 25 may be suited to different operational temperature ranges and system configurations. It will be appreciated 11 that different operating temperature ranges to those detailed in Table I could be achieved 12 by using different first and second liquids 21, 25 and different combinations of the first and 13 second liquids 21, 25 beyond the disclosed liquids and combinations in Table I. Table I: Examples of: the first liquid; second liquid; and a temperature range of the 16 uncoo ed body to be cooled by a cooling apparatus comprising the first and second liquids.

First Liquid Second Liquid Operating Temperature Range (0C) 1-Chloro-3,3,3- De-mineralised water Over 19 °C trfluoropropene (Trans chloro trifluoropropene) R1233ZD (Boiling point: 18.3 °C) Dichlorotrifluoroethane De-mineralised water Over 28 °C (Boiling point: 27.6 °C) 1,2-Dichlorotetrafluoroethane De-mineralised water Over 4 °C (Boiling point: 3.5 °C) 1,1,1,3,3,3- De-mineralised water Over 0 °C Hexafluoropropane (Boiling point: -1.7 ^C) 2,3,3,3-Tetrafluoropropene De-mineralised water Over -20 °C (R1234 YF) (Boiling point: -29.29 °C) Trans-1,3,3,3- De-mineralised water Over -18 °C tetrafluoroprop-1-ene ( R-1234ze) (Boiling point: -18.89°C) (Z)-1-Chloro-2,3,3,3- De-mineralised water Over 15°C Tetrafluoropropane (R1224yd(Z)) (Boiling point: 15 oC) trans-1,1,1,4,4,4-hexafluoro- De-mineralised water Over 7.5 °C 2-butene (R1336mzzE) (Boiling point: 7.5 °C) 2 Similar to the embodiment of Figure 2, the body 17 to be cooled depicted in Figure 3 is 3 located within the cooling apparatus 16. More specifically, the body 17 is located within 4 the housing 18. It is preferable for the body 17 to be immersed, or at least partially immersed, within the first liquid 21.

7 In operation, heat from the body 17 evaporates a quantity of the first liquid 21 to form 8 gaseous bubbles 23. The gaseous bubbles 23 have a lower density than both the first 9 liquid 21 and the second liquid 25. As such, the gaseous bubbles 23 move in the positive z-direction, through the second liquid 25 and into the second portion 27 of the housing 18.

ii As such, the embodiment of Figure 3 operates in a similar manner to that of Figure 2, in 12 that evaporating a quantity of the first liquid 21, causes the body 17 to cool since heat from 13 the body 17 is converted into kinetic energy in the form of the motion of the gaseous 14 bubbles 23. The gaseous bubbles 23 provide a means for thermal convection of the thermal energy of the body 17.

17 The gaseous bubbles 23 dissipate kinetic energy to the housing 18. The gaseous bubbles 18 23 condense to form liquid bubbles 24. The cooled liquid bubbles 24 sink back towards 19 the base end 20 of the housing 18 due to gravity, into the first portion 26 of the housing 18, as the density of the liquid bubbles 24 is greater than the density of the second liquid 25.

21 As such, the liquid bubbles 24 are circulated back towards the body 17 to absorb more 22 heat. The housing 18 dissipates heat to the surrounding environment of the cooling 23 apparatus 16 by means of thermal conduction.

As another additional or alternative feature, the dissipation of the heat from the housing to 26 the surrounding environment by thermal conduction may be further enhanced by the 27 cooling apparatus 16 of Figure 3 comprising a condensing apparatus 28. The cooling 28 apparatus 28 is located at the top end 19 of the housing 18. In operation, once the 29 gaseous bubbles 23 have traversed through the second portion 27 of the housing 18, the 1 gaseous bubbles 23 enter the condensing apparatus 28 which condenses the gaseous 2 bubbles 23 to liquid bubbles 24. In other words, instead of the gaseous bubbles 23 3 passively condensing once they have lost sufficient energy within the housing 18, the 4 condensing apparatus 28 actively condenses a portion of the gaseous bubbles 23. These liquid bubbles 24 then return to the first portion 26 of the housing 18 by either two external 6 return pipes 29 directly connecting the condensing apparatus to the base end 20 of the 7 housing 18 and or by sinking back through the second portion 26 of the housing 18. The 8 condensing apparatus 28 removes the heat, specifically the latent heat, from the gaseous 9 bubbles 23, which is dissipated to the surrounding environment of the cooling apparatus 16 by means of thermal conduction.

12 The external return pipes 29 further dissipates heat, specifically the sensible heat from the 13 liquid bubbles 24 by thermal conduction, resulting in a decrease in temperature of the 14 liquid bubbles 24. As depicted in Figure 3, preferably, the external return pipes 29 are external to the housing 18 and so heat is dissipated to the surrounding environment of the 16 cooling system 15b. The cooled liquid bubbles 24 are returned to the first portion 26 of the 17 housing 18, below the body 17 and establish a temperature gradient within the first liquid 18 21 across the body 17.

A key aspect of the present invention is establishing a sufficiently large temperature 21 gradient across the body 17 to drive the thermal convention, the motion of the gaseous 22 bubbles 23 and thereby the heat transfer away from the body 17. A large temperature 23 gradient will result in a sufficient heat transfer to efficiently operate the cooling system 15b 24 without the pressure and boiling point of the first liquid 21 changing.

26 As an example, consider a body 17 with an uncooled temperature of 21°C. If the cooling 27 system 15a is configured to maintain the temperature of the body 17 at 14°C, the pressure 28 of the first liquid 21 is preferably sufficiently low at the base end 20 of the housing 18 such 29 that the boiling point of the first liquid 21 is less than 14°C. This is achieved if the temperature of the surrounding environment is less than 14°C and or if the condensing 31 apparatus 28 operates efficiently enough to dissipate the heat from the body 17 without 32 the pressure within the condensing apparatus 28 rising above a certain value.

34 To summarise the cooling process in terms of vapour pressure, the first liquid 21, for example R1336mzzE, absorbs heat from the body 17 and changes phase to form gaseous 1 bubbles 23. The vapour pressure of the gaseous bubbles 23 is higher than the operational 2 pressure, so gaseous bubbles 23 rise upwards with significant velocity and force. As the 3 gaseous bubbles 23 reach the condensing apparatus 28, the pressure inside the 4 condensing apparatus 28 should be less than the condensation pressure of the gaseous bubbles 23 and so the gaseous bubbles 23 condense to liquid bubbles 24. The liquid 6 bubbles 24 have a relatively high density and so fall back to the base end 20 of the 7 housing 18 due to gravity.

9 In operation, a pressure gradient will form between the top and base ends 19, 20 of housing 18. The top end 19 has a lower pressure than the base end 20. In order to 11 maintain the cooling process, it is preferably that the pressure at the base end 20 of the 12 housing 18 is configured to be low enough to keep the boiling point of the first liquid 21 just 13 above the temperature at which the body 17 should be maintained. If the condensing 14 apparatus 28 is not operating at the required efficiency, then the pressure increases within the condensing apparatus 28 which will in turn increase the pressure within the housing 18 16 and so the boiling point of the first liquid 21 will increase. As a result, the temperature of 17 the body 17 will also increase. The pressure can be a key consideration when 18 configurating the cooling apparatus 16.

As a further example of the cooling apparatus 16 in operation, the gaseous bubbles 23 in a 21 vapour state may rise away from the body 17 at 14°C and the condensed liquid bubbles 24 22 in a liquid state return to the body 17 also at 14°C. In this example, the latent heat is 23 removed but the temperature of the system does not change. The heat from the body 17 24 is sufficient to evaporate the first liquid 21.

26 As another additional or alternative feature, the functionality of the one or more external 27 return pipes 29 may be enhanced by a heat exchanger 30, as depicted in Figures 3 and 4.

28 The heat exchanger 30 takes the form of a plurality of channels 31, connected in parallel, 29 through which the liquid bubbles 24 traverse. The plurality of channels 31 increases the thermal contact with the surrounding environment of the cooling system 15, increasing the 31 dissipated heat, thermal conduction and thereby the cooling of the liquid bubbles 24.

33 As an additional or alternative embodiment, it will be appreciated the cooling apparatus 16 34 comprises a third liquid. The cooling apparatus 16 may comprise multiple liquids.

1 As further additional or alternative features, the housing 18 depicted in Figure 3 comprises 2 a sealable inlet port 32 and a sealable outlet port 33. The sealable inlet port 32 is located 3 at a top end 19 of the housing 18, through the second portion 27 of the housing 18 and 4 provides a means for adding the first and second liquids 21, 25 into the housing 18.

Similarly, the sealable outlet port 33 is located, at a base end 20 of the housing 18, 6 through the first portion 26 of the housing 18 and provides a means for draining the first 7 and second liquids 21, 25 from the housing 18. In order to fill and maintain the housing 18 8 at a positive pressure, the first and second liquids 21, 25 may be pumped to and from the 9 housing 18 by a pumping system 34. The cooling apparatus 16 is a closed device such that the first and second liquids 21, 25 are not added or removed during operation. ii

12 As another additional or alternative feature, the cooling apparatus 16 of Figure 3 further 13 comprises storage tanks 35. Each storage tank 35 comprises a different liquid such as 14 those listed in Table 1 and the storage tanks are connected to the pumping system 34.

The liquids may be compressed for storage within the storage tanks 35. The pumping 16 system 34 facilitates removing the first and second liquids 21, 25 from the housing 18 to 17 be stored within the respective storage tanks 35. The pumping system 34 can also 18 facilitate replacing the first and second liquids 21, 25 with alternative combinations of 19 liquids. As such, the combination of the first and second liquid 21, 25 can be optimised according to the operational conditions of the cooling apparatus 16. The process of 21 removing and replacing the first and second liquids 21, 25 according to the operational 22 requirements may be automated by the pumping system 34. As such the pumping system 23 34 may comprise sensors to monitor the cooling apparatus 16 and the surrounding 24 environment. Whilst Figure 2 depicts two storage tanks 35 it will be appreciated there may be a plurality of storage tanks 35 offering numerous alternative combinations of first and 26 second liquids 21, 25.

28 As another additional or alternative feature, the cooling apparatus 16 of Figure 3 further 29 comprises a sink 36 of the first liquid 21. The sink 36 is connected to the housing 18 and maintains the level of the first liquid 21 within the first portion 26 of the housing 18. As the 31 first liquid 21 evaporates within the cooling apparatus 16, this may induce non negligible 32 changes in pressure and or volume within the cooling apparatus 16. The sink 36 33 minimises any changes in pressure and or volume.

1 Figure 5 depicts an alternative cooling system 15c which may comprise the same 2 preferable and optional features as the cooling systems 15a, 15b depicted in Figures 2 to 3 4.

Instead of a unitary housing 18 as depicted in Figures 2 and 3, the housing 18 may 6 comprise multiple chambers. As an example, the cooling apparatus 16 depicted in Figure 7 5 comprises a first chamber 37, a second chamber 38 with pipes 39 fluidly connecting the 8 first and second chambers 37, 38. The first and second liquids 21, 25 are located within 9 the first chamber 37. Furthermore, the first liquid 21 is also located within the second chamber 38 and circulated between the first and second chambers 37, 38 by means of the 11 pipes 39 and a circulation pump 40.

13 As can be seen in Figure 5 the body 17 to be cooled, is located within the second chamber 14 38 immersed within the first liquid 21. The cooling apparatus 16 of Figure 5 operates in a similar manner as the cooling apparatus 16 of Figure 3. Heat from the body 17 evaporates 16 a quantity of the first liquid 21 located within the second chamber 38 and the resulting 17 gaseous bubbles 23 are circulated to the first chamber 37 through the pipes 39, driven by 18 the circulation pump 40. The gaseous bubbles 23 move within the first chamber 37 in the 19 positive z-direction, through the second liquid 25, and into the condensing apparatus 28.

Once the gaseous bubbles 23 have been condensed to liquid bubbles 24 and returned to 21 the first chamber 37, the cooled first liquid 24 is circulated back into the second chamber 22 38.

24 A key advantage of the cooling system 15b of Figure 5 is that the body 17 may be immersed in a separate chamber from the first chamber 37 which houses the first and 26 second liquids 21, 25, providing more flexibility on the location body 17 to be cooled.

28 Figure 6 depicts an alternative cooling system 15d which may comprise the same 29 preferable and optional features as the cooling systems 15a, 15b, 15c depicted in Figures 2 to 5.

32 Similar to the embodiment of Figure 5, the housing 18 depicted in Figure 6 comprises a 33 first and second chamber 37, 38 with the body 17 is also located within the second 34 chamber 38. The first and second liquids 21, 25 is located within the first chamber 37.

However, in contrast to Figure 5, the body 17 is immersed with a fluid 41 located within the 1 second chamber 38. The first and second chambers 37, 38 are not fluidly connected in 2 that no liquid and or vapour can be transferred between the two chambers 37, 38. In other 3 words, the first and second liquids 21, 25 cannot mix with the fluid 41. Whilst there is not a 4 fluid connection, the cooling apparatus 16 further comprises a heat exchanging apparatus 42 which thermally connects the first and second chambers 37, 38.

7 The heat exchanging apparatus 42 takes the form of a coiled pipe 43 extending into the 8 first chambers 37. More specifically, the coiled pipe 43 is located within the interior volume 9 22 of the housing 18. In operation, heat from the body 17 is transferred to the fluid 41.

The fluid 41 is circulated through a circulation loop 6d to the coiled pipe 43 by means of a 11 circulation pump 40. Heat is transferred from the fluid 41 with the coiled pipe 43 to the first 12 liquid 21, evaporating a quantity of the first liquid 21.

14 In other words, the first liquid 21 within the first chamber 37 cools the heated fluid 41 and the resulting cooled fluid 41 is circulated back towards the body 17 to absorb more heat.

16 The process of absorbing heat from body 17, transferring the heat to the housing 18 by 17 thermal convection and dissipating the heat from the housing 18 by thermal conduction is 18 repeated resulting in the continual cooling the body 17.

The fluid 41 sealed within the second chamber 38, circulation loop 6d and heat 21 exchanging apparatus 42 does not mix with any liquid or gas external to the circulation 22 loop 6 such as air surrounding the cooling system 15d. The fluid 41 can be any suitable 23 fluid such as a refrigerant known in the art.

An advantage of the circulation loop 6d is that the fluid 41 may be chosen according to the 26 operational parameters of the cooling system 15d, for example the operational 27 temperature range. Whilst the fluid 41 located within the second chamber 38 and 28 circulation loop 6d could be air, in contrast to circulation loop 6a of Figure 1, the circulation 29 loop 6d is not limited to circulating air. As such, the fluid 41 of the circulation loop 6d may have desirable thermal and chemical properties to enhance the cooling system 15d.

31 Furthermore, it may be financially more favourable to operate with a particular fluid 41 32 instead of air. In particular, the fluid 41 of the circulation loop 6d may not demand 33 relatively more expensive apparatus required for operating with air.

1 Figure 7 depicts an alternative cooling system 15e which may comprise the same 2 preferable and optional features as the cooling systems 15a, 15b, 15c, 15d depicted in 3 Figures 2 to 6.

Similar to the embodiment of Figures 3, the cooling apparatus 16 of Figure 6 comprises a 6 unitary housing 18 with a condensing apparatus 28 located at the top end 19 of the 7 housing 18. However, the cooling apparatus of Figure 6 does not comprise one or more 8 external return pipes 29 as depicted in Figure 2. Instead, the liquid bubbles 24 return to 9 the first portion 26 of the housing 18 by means of an internal return pipe 44 and or by sinking back through the second portion 26 of the housing 18. Advantageously, the 11 embodiment of Figure 7 is simpler to manufacture and maintain as has minimal 12 components.

14 Figure 8 depicts an alternative cooling system 15f which may comprise the same preferable and optional features as the cooling systems 15a, 15b, 15c, 15d, 15e depicted 16 in Figures 2 to 7.

18 Similar to the embodiment of Figures 3, the cooling apparatus 16 of Figure 7 comprises a 19 unitary housing 18 with a condensing apparatus 28 located at the top end 19 of the housing 18. The first and second liquids 21, 25 are located within the housing 18. The 21 first liquid 21 is occupies the interior volume 22 up to a first liquid level 45. The second 22 liquid 25 occupies the interior volume 22 from the first liquid level 45 up to the second 23 liquid level 46. In previous embodiments, the first and second liquids 21, 25 completely fill 24 the housing. However, the housing of Figure 7 further comprises one or more fluids 47. It will be appreciated that the one or more fluids 47 are an optional feature of the cooling 26 apparatus 16.

28 The cooling apparatus 16 of Figure 7 further comprises multiple external return pipes 29 connecting difficult regions of the cooling apparatus 16. A first external return pipe 29a connects the condensing apparatus 28 to the base end 20 of the housing 18. A second 31 return pipe 29b connects the housing 18 in the region of the second liquid level 46 to the 32 base end 20 of the housing 18. A third return pipe 29c connects the housing 18 in the 33 region of the first liquid level 45 to the base end 20 of the housing 18. The three return 34 pipes 29a, 29b, 29c siphon off cooled liquid bubbles 24 and return these liquid bubbles 24 to the base end 20 of the housing 18, below the body 17, and so maintaining a sufficiently 1 large temperature gradient across the body 17 to drive heat transfer. Each of the three 2 return pipes 29a, 29b, 29c may comprise a heat exchanger 30 to further enhance the heat 3 dissipation to the surrounding environment of the cooling apparatus 16.

Figure 9 depicts an alternative cooling system 15g which may comprise the same 6 preferable and optional features as the cooling systems 15a, 15b, 15c, 15d, 15e, 151 7 depicted in Figures 2 to 8.

9 The cooling apparatus 16 depicted in Figure 9 further comprises a cone apparatus 48 located over the top end 19 of the housing 18. The cone apparatus 48 comprises an inlet 11 49 and an outlet 50, the inlet 49 having a larger dimension in comparison to the outlet 50.

12 The cone apparatus 48 located and orientated to channel air flow and convention currents 13 around the cooling apparatus 15f.

In operation, air 51 surrounding the housing 18 of the cooling apparatus 16 is heated and 16 rises in the positive z direction, entering the inlet 49 of the cone apparatus 48. As the air 17 51 continues to rise in the positive z direction within the cone apparatus 48, the air 51 18 accelerates due to the constricting dimension of the cone apparatus 48 and exits by the 19 outlet 50. The cone apparatus 48 enhances the convection currents around the cooling apparatus 16. As such, the cooling apparatus 16 can more efficiently dissipate energy to 21 the surrounding environment.

23 Figure 10 depicts an alternative cooling system 15h which may comprise the same 24 preferable and optional features as the cooling systems 15a, 15b, 15c, 15d, 15e, 15f, 15h depicted in Figures 2 to 9.

27 The embodiment of Figure 10 comprises a unitary housing 18 located within which are the 28 first and second liquids 21, 25. It will be appreciated that this embodiment may comprise 29 only a first liquid 21, like the embodiment of Figure 2. However, in contrast to previous embodiments, the body 17 to be cooled depicted in Figure 10 is not located within the 31 housing 18. The body 17 is located external to the housing 18.

33 Heat is transferred from the body 17, located outside the housing 18, to the first and 34 second liquids 21, 25 within the housing 18 by a circulation loop 6h sealed within which is a fluid 52. As can be seen in Figure 10, the circulation loop 6h comprises a first heat 1 exchanging apparatus 42a located proximal to the body 17, a second heat exchanging 2 apparatus 42b located within the housing 18, pipes 53 connecting the first and second 3 heat exchanging apparatus 42a, 42b and a circulation pump 7. The first and second heat 4 exchanging apparatus 42a, 42b may take the form of coiled pipes 43.

6 In operation, the fluid 52 within the first heat exchanging apparatus 42a absorbs heat from 7 the body 17. The heated fluid 52 is circulated about the circulation loop 6h by a circulation 8 pump 7 to the second heat exchanging apparatus 42b which transfers heat from the fluid 9 52 to the first and second liquids 21, 25 within the housing 18. The cooled fluid 52 is then circulated back to the first heat exchanging apparatus 42a to absorb heat from the body 11 17.

13 In the context of the cooling systems 15 of Figures 2 to 10, the body 17 is described as a 14 data centre 2 and specifically, computer systems 4. It will be appreciated that the cooling systems 15 are not limited to cooling a data centre 2 and may be employed to cool any 16 suitable body such as a heat source or building. For example, the cooling systems 15 may 17 be employed to cool an office building or even a chiller room for chilled food products.

19 Method of Manufacturing a Cooling apparatus 21 Figure 11 shows a flow chart for a method of manufacturing the cooling apparatus 16. The 22 method comprises: providing a housing (S1001); providing a first liquid located within the 23 housing (51002); wherein, in operation, heat from the body evaporates a quantity of the 24 first liquid to form a first liquid vapour; the first liquid vapour transports the heat away from the body to the housing by thermal convection; and the heat dissipates to a surrounding 26 environment via the thermal conduction through the housing (31003).

28 In addition, the method of manufacturing the cooling apparatus 16 may optionally comprise 29 characterising a body which is to be cooled, such as a data centre 2. For example, this may include characterising properties such as the temperature of the body without any 31 cooling, a target temperature of the body with cooling, the temperature variability of the 32 body, the dimensions, shape and composition 34 As a further addition, the method of manufacturing the cooling apparatus 16 may optionally comprise utilising the characteristics of the body to determine the optimum parameters of a 1 cooling apparatus 16. For example, this optimisation process may include determining: 2 the dimensions and shape of the cooling apparatus 16; the chemical composition of the 3 first liquid 21; if a second liquid is required and if so, the volume, relative ratio and 4 chemical composition of the first and second liquids 21, 25; if a condensing apparatus 28 is required and if so, the configuration of the condensing apparatus 28; if one or more 6 return pipes are required and the if so, the configuration of the one or more return pipes; if 7 a sink 36 is required; if storage tanks 35 are required; if a heat exchanging apparatus 42 is 8 required and the location of the body 17 within the cooling apparatus 16. As an example 9 of the parameter dependency, the higher the temperature of the body and the greater the difference between the uncooled temperature of the body and desired cooled temperature 11 of the body, the greater required cooling capacity of the cooling apparatus 16. When 12 choosing the first and second liquids 21, 25 factors such as the heat capacity, relative 13 density and relative boiling points are key considerations. It is advantageous to optimise 14 the cooling apparatus 16 as this ensures the cooling apparatus 16 can operate, in other words, the body will provide enough heat to evaporate any quantity of the first liquid 21.

16 Furthermore, the optimisation ensures the cooling apparatus 16 can operate efficiently.

18 Method of Manufacturing a Cooling System A method of manufacturing a cooling system 15 comprises providing a cooling apparatus 21 16 in accordance with the flow chart depicted in Figure 16, as described above, and 22 providing a body, such as a data centre 2 which is to be cooled.

24 The cooling systems 15 disclosed herein have numerous advantages. In general, the cooling systems 15 all comprises a cooling apparatus 16 which can passively dissipate 26 heat. The cooling apparatus 16 can operate without drawing electrical power and so is 27 financially favourable and environmentally friendly.

29 The cooling apparatus 16 does not rely on conventional thermodynamic cycles, but instead provides an alternative mechanism for dissipating heat by utilising a phase change 31 of the first liquid 21 to a first liquid vapour 23. The gaseous bubbles 23 transport the heat 32 away from a body by thermal convection. The heat is dissipated to a surrounding 33 environment via thermal conduction. The cooling apparatus 16 has minimal moving 34 components, reducing the amount of maintenance that may be required and maximising the lifetime of the device.

2 Advantageously, the cooling apparatus 16 has numerous configurations. The cooling 3 apparatus 16 can dissipate heat solely through thermal conducting through the housing 4 18. The efficiency of the cooling apparatus 16 can be enhanced by the addition of a condensing apparatus 28. The condensing apparatus 28 provides an additional 6 mechanism to dissipate heat via thermal conduction. As an alternative or in addition, the 7 efficiency of the cooling apparatus 16 may also be enhanced by the addition of a second 8 liquid.

Furthermore, the cooling apparatus 16 is scalable as can be adapted for different bodies to 11 be cooled. As such, the dimensions of the cooling apparatus can be adapted to the 12 desired size and resulting expense. The cooling apparatus 16 is a sealed device with 13 minimal moving components so is relatively safe.

A cooling apparatus is disclosed. The cooling apparatus is suitable for cooling a body.

16 The cooling apparatus comprises a housing, a first liquid located within the housing. In 17 operation, heat from the body evaporates a quantity of the first liquid to form a first liquid 18 vapour, the first liquid vapour transports the heat away from the body to the housing by 19 thermal convection, and the heat dissipates to a surrounding environment via the thermal conduction through the housing. The cooling apparatus can cool a body whilst drawing 21 minimal or even no electrical power. As such the cooling apparatus is environmentally 22 friendly and cheaper to operate.

24 Throughout the specification, unless the context demands otherwise, the terms "comprise" or "include", or variations such as "comprises" or "comprising", "includes" or "including' will 26 be understood to imply the inclusion of a stated integer or group of integers, but not the 27 exclusion of any other integer or group of integers. Furthermore, unless the context clearly 28 demands otherwise, the term "or' will be interpreted as being inclusive not exclusive.

The foregoing description of the invention has been presented for purposes of illustration 31 and description and is not intended to be exhaustive or to limit the invention to the precise 32 form disclosed. The described embodiments were chosen and described in order to best 33 explain the principles of the invention and its practical application to thereby enable others 34 skilled in the art to best utilise the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Therefore, further 1 modifications or improvements may be incorporated without departing from the scope of 2 the invention as defined by the appended claims.

Claims

1 Claims 3 1. A cooling apparatus suitable for cooling a body, the cooling apparatus comprises: 4 a housing; and a first liquid located within the housing; 6 wherein, in operation, 7 heat from the body evaporates a quantity of the first liquid to form a first liquid vapour; 8 the first liquid vapour transports the heat away from the body to the housing by thermal 9 convection; and the heat dissipates to a surrounding environment via thermal conduction through the ii housing.13

2. The cooling apparatus as claimed in claim 1, wherein heat is only transferred to the 14 surrounding environment via thermal convection provided by the first liquid and thermal conduction through the housing.17

3. The cooling apparatus as claimed in either of claims 1 or 2, wherein the first liquid 18 occupies an interior volume of the housing.

4. The cooling apparatus as claimed in any of the preceding claims, wherein the first 21 liquid is 1-Chloro-3,3,3-trifluoropropene (R1233ZD); or Dichlorotrifluoroethane; or 1,2- 22 Dichlorotetrafluoroethane; or 1,1,1,3,3,3-Hexafluoropropane; or 2,3,3,3- 23 tetrafluoropropene (R1234 YE); or Trans-1,3,3,3-tetrafluoroprop-1-ene (R-1234ze); 24 1,1,1,3,3-Pentafluoropropane (R245fa); or (Z)-1-Chloro-2,3,3,3-Tetrafluoropropane (R1224yd(Z)); or trans-1,1,1,4,4,4-hexafluoro-2-butene (R1336mzzE); or de- 26 mineralised water.28

5. The cooling apparatus as claimed in any of the preceding claims, wherein the cooling 29 apparatus comprises a second liquid.31

6. The cooling apparatus as claimed in claim 5, wherein the first liquid has a higher 32 density and lower boiling point than the second liquid.1

7. The cooling apparatus as claimed in claims 5 or 6, wherein the first and second liquids 2 occupy an interior volume of the housing and the first and second liquids mix within the 3 interior volume of the housing.

8. The cooling apparatus as claimed in claims 5 to 7, wherein the first liquid is 1-Chloro- 6 3,3,3-trifluoropropene (R1233ZD) and the second liquid is de-mineralised water; or the 7 first liquid is Dichlorotrifluoroethane and the second liquid is de-mineralised water; the 8 first liquid is 1,2-Dichlorotetrafluoroethane and the second liquid is de-mineralised 9 water; the first liquid is 1,1,1,3,3,3-Hexafluoropropane and the second liquid is de-mineralised water; the first liquid is 2,3,3,3-Tetrafluoropropene (R1234 YF) and the ii second liquid is de-mineralised water; the first liquid is R-1234ze (Trans-1,3,3,3- 12 tetrafluoroprop-1-ene) and the second liquid is de-mineralised water; or the first liquid 13 is (Z)-1-Chloro-2,3,3,3-Tetrafluoropropane (R1224yd(Z)) and the second liquid is de- 14 mineralised water; or the first liquid is trans-1,1,1,4,4,4-hexafluoro-2-butene (R1336mzzE) and the second liquid is de-mineralised water.17

9. The cooling apparatus as claimed in any of the preceding claims, wherein the cooling 18 apparatus further comprises one or more fluids.

10. The cooling apparatus as claimed in any of the preceding claims, wherein the cooling 21 apparatus further comprises a condensing apparatus.23

11. The cooling apparatus as claimed in claim 10, wherein the condensing apparatus is 24 located at a top end of the housing.26

12. The cooling apparatus as claimed in any of the preceding claims, wherein the cooling 27 apparatus further comprises one or more return pipes.29

13. The cooling apparatus as claimed in any of the preceding claims, wherein the one or more return pipes comprise one or more heat exchangers.32

14. The cooling apparatus as claimed in any of the preceding claims, wherein the housing 33 comprises two or more chambers.1

15. The cooling apparatus as claimed in claim 14, wherein the two or more chambers are 2 fluidly connected by one or more pipes or the two or more chambers are fluidly isolated 3 and thermally connected by a heat exchanging apparatus which transfers heat 4 between the two or more chambers.6

16. The cooling apparatus as claimed in any of the preceding claims, wherein the housing 7 is sealable.9

17. The cooling apparatus as claimed in any of the preceding claims, wherein the cooling apparatus comprises a circulation loop, the circulation loop transfers heat external to 11 the housing, to within the housing of the cooling apparatus.13

18. A cooling system comprising the cooling apparatus as claimed in any of claims 1 to 17 14 and a body to be cooled.16

19. The cooling system as claimed in claim 18, wherein the body to be cooled is located 17 within the cooling apparatus, optionally within the housing of the cooling apparatus, 18 optionally at least partially immersed within the first liquid.

20. The cooling system as claimed in claim 18, wherein the body to be cooled is located 21 external to the cooling apparatus.23

21. A method of manufacturing a cooling apparatus suitable for cooling a body, the method 24 comprising, providing a housing; and 26 providing a first liquid located within the housing; 27 wherein, in operation, 28 heat from the body evaporates a quantity of the first liquid to form a first liquid vapour; 29 the first liquid vapour transports the heat away from the body to the housing by thermal convection; and 31 the heat dissipates to a surrounding environment via thermal conduction through the 32 housing.34

22. A method of manufacturing a cooling system comprising, 1 providing a cooling apparatus in accordance with the method as claimed in claim 21; 2 and 3 providing a body to be cooled.

23. The method of manufacturing a cooling system as claimed in claim 22, wherein 6 providing a body to be cooled comprises immersing or partially immersing the body 7 within the first liquid.9

24. A method of operating a cooling system comprising suitable for cooling a body, the method comprising, ii transferring heat from the body to evaporate a quantity of a first liquid located within a 12 housing, to form a first liquid vapour; 13 the first liquid vapour transporting the heat away from the body to the housing by 14 thermal convection; and dissipating the heat to a surrounding environment via the thermal conduction through 16 the housing.18

25. Use of a cooling apparatus as claimed in claims 1 to 17 and or use of a cooling system 19 as claimed in claim 18 to 20 and or use of a method of operating a cooling system as claimed in claim 23 to cool a body.