Patent Description:
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 system has numerous applications, ranging from domestic fridges and freezers to air conditioning systems for buildings. <CIT> discloses a cooling apparatus having the features of the preamble of claim <NUM>.

<FIG> depicts a vapour-compression refrigeration system <NUM> known in the art used to cool a data centre <NUM>. The data centre <NUM> takes the form of a building <NUM> housing computer systems <NUM>. The temperature within the building <NUM> is often raised above ambient temperature to, for example, <NUM> due to the operation of the computer systems <NUM>. The purpose of the vapour-compression refrigeration system <NUM> is to lower the temperature within the building <NUM> such that the computer systems <NUM> do not overheat.

High temperature (<NUM>) air <NUM> within the building <NUM> is drawn into circulation loop <NUM>, by means of a circulation fan <NUM>. Whilst traversing the circulation loop <NUM>, the high temperature air <NUM> passes through an evaporator <NUM> and loses heat. The resulting low temperature air <NUM> with a temperature of <NUM> is pumped into the building <NUM>.

The evaporator <NUM> is part of a sealed refrigeration loop <NUM> which contains a working fluid <NUM>, commonly known as a refrigerant. The evaporator <NUM> transfers heat from the high temperature air <NUM> to the working fluid <NUM>. As such, the evaporator <NUM> can more generally be considered a heat exchanging apparatus. The heat induces a phase change in the working fluid <NUM> from a liquid to a gas. The gaseous working fluid <NUM> circulates about the refrigeration loop <NUM> where it is then compressed by a compressor <NUM> resulting in a temperature increase of the gaseous working fluid <NUM> up to, for example, <NUM>. The hot (<NUM>) compressed working fluid <NUM> is then cooled in a condenser <NUM> such that the gaseous working fluid <NUM> expels heat and condenses back to a liquid, resulting in a liquid compressed working fluid <NUM> with a reduced temperature of, for example, <NUM>. After which, the temperature of the liquid working fluid <NUM> is reduced further to, for example, -<NUM> by reducing the pressure of the liquid compressed working fluid <NUM> by means of an expansion valve <NUM>. The cold (-<NUM>) uncompressed working fluid is recirculated into the evaporator where, by means of thermal diffusion, heat again transfers from the high temperature air <NUM> to the working fluid <NUM>. The cycle repeats continually cooling the high temperature air <NUM> originating from the building <NUM>.

The vapour-compressed refrigeration system <NUM> as depicted in <FIG> requires electrical power to operate. In particular, the circulating fan <NUM>, compressor <NUM> and condenser <NUM> all draw electrical power. Disadvantageously, such systems <NUM> can draw significant amounts of electrical power. A relatively large data centre can equate to electrical power requirements equivalent to a town. Such a large electrical power consumption is expensive and also has a significant environmental impact.

Another disadvantage of the vapour-compressed refrigeration system <NUM> is that all the components, in particular the circulating fan <NUM>, compressor <NUM> and condenser <NUM>, require maintenance. This is an additional financial burden and the vapour-compressed refrigeration system <NUM> cannot operate during the required maintenance breaks.

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

According to a first aspect of the present invention there is provided a cooling apparatus as provided by claim <NUM>. Optional features are provided by dependent claims <NUM> to <NUM>.

According to a second aspect of the present invention there is provided a cooling system as provided by claim <NUM>. Optional features are provided by dependent claims <NUM> to <NUM>.

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

According to a third aspect of the present invention there is provided a method of manufacturing a cooling apparatus as provided by claim <NUM>. Optional features are provided by dependent claim <NUM>.

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

According to a fourth aspect of the present invention there is provided a method of manufacturing a cooling system comprising as provided by claim <NUM>.

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 vice versa.

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 and the proportions of certain parts have been exaggerated to better illustrate details and features of embodiments of the invention.

An explanation of the present invention will now be described with reference to <FIG>.

<FIG> depicts a cooling system 15a suitable for cooling a data centre <NUM> which takes the form of computer systems <NUM> housed within a building <NUM>. The cooling system <NUM> comprises a cooling apparatus <NUM> and a heat transfer apparatus to transfer heat from the data centre <NUM> to the cooling apparatus <NUM>. In the embodiment of <FIG>, the heat transfer apparatus takes the form of a circulation loop 6a and a circulation fan <NUM>. The circulation fan <NUM> draws high temperature air <NUM> within the building <NUM> about the circulation loop 6a to the cooling apparatus <NUM>.

More specifically, the circulation loop 6a comprises pipes <NUM> which channel high temperature air <NUM> to the cooling apparatus <NUM>. The cooling apparatus <NUM> cools the high temperature air <NUM> resulting in low temperature air <NUM>. The low temperature air <NUM> is circulated about the circulation loop 6a into the building <NUM> and cools the computer systems <NUM>.

As can clearly be seen in <FIG>, the cooling apparatus <NUM> comprising a substantially cylindrical, sealable housing <NUM> with a substantially conical lid <NUM>. The housing <NUM> comprises stainless steel, specifically, SA516 GR. For ease of understanding, <FIG> and <FIG> depict a cylindrical coordinate system with r, θ, and z axes.

The cooling apparatus <NUM> can be seen to comprise a first liquid <NUM> and a second liquid <NUM> both of which are located within the housing <NUM>. The first and second liquids <NUM>, <NUM> occupy an interior volume <NUM> of the housing <NUM>. The first liquid <NUM> has a higher density but lower boiling point in comparison to the second liquid <NUM>. As such, whilst the first and second liquids <NUM>, <NUM> are free to mix within the housing <NUM>, the first liquid <NUM> locates within a first portion <NUM> of the housing <NUM>, at the base of the housing <NUM>, and the second liquid <NUM> locates within a second portion <NUM> of the housing <NUM>, above the first liquid <NUM>.

By way of example, the first liquid <NUM> may be trans-<NUM>-choloro-<NUM>,<NUM>,<NUM>-trifluoroprop-<NUM>-ene (R1233ZD), also referred to as trans chloro trifluoropropene, and the second liquid <NUM> may be de-mineralised water. The density of R1233ZD is approximately <NUM> times that of de-mineralised water and R1233ZD has a boiling point of <NUM> which is lower than the boiling point of demineralised water, <NUM>. A cooling apparatus <NUM> comprising R1233ZD and de-mineralised water as the first and second liquids <NUM>, <NUM> is suitable for cooling high temperature air <NUM>, over <NUM>, from a data centre <NUM>. For the cooling apparatus <NUM> to operate, both the first and second liquids <NUM>, <NUM> are required to be in liquid form at ambient temperature. As such, the ambient temperature of the environment surrounding the cooling apparatus <NUM> should be below the boiling point of the first and second liquids <NUM>, <NUM>, in this case, below <NUM>.

Further examples of the first and second liquids <NUM>, <NUM> are provided in Table I along with an operating temperature range of a cooling apparatus <NUM> comprising the first and second liquids <NUM>, <NUM>. The combinations of the first and second liquids <NUM>, <NUM> may be suited to different operational temperature ranges and system configurations. It will be appreciated that different operating temperature ranges to those detailed in Table I could be achieved by using different first and second liquids <NUM>, <NUM> and different combinations of the first and second liquids <NUM>, <NUM> beyond the disclosed liquids and combinations in Table I.

The cooling apparatus <NUM> also comprises a heat exchanging apparatus <NUM> which transfers heat from the high temperature air <NUM> to the first liquid <NUM> (and second liquid <NUM>) in order to evaporate a quantity of the first liquid <NUM>. The first and second liquids <NUM>, <NUM> are not directly exposed to the high temperature air <NUM> or any external fluid carrying heat from the data centre <NUM>. In the embodiment of <FIG> and <FIG>, the heat exchanging apparatus <NUM> takes the form of a coiled pipe <NUM> extending along the z axis of the cooling apparatus <NUM>.

More specifically, the coiled pipe <NUM> is located within the interior volume <NUM> of the housing <NUM>. The coiled pipe <NUM> can be considered a portion of the air circulation loop 6a that directs high temperature air <NUM> through the cooling apparatus <NUM>. The coiled pipe <NUM> comprises an inlet <NUM> towards the base end <NUM> of the housing <NUM> and an outlet <NUM> towards a top end <NUM> of the housing <NUM>, in the conical lid <NUM>.

The cooling apparatus <NUM> further comprises a plurality of independent energy dissipation members <NUM>. As can be clearly seen in <FIG>, the plurality of independent energy dissipation members <NUM> take the form of rods <NUM>. Each rod <NUM> comprises a first end <NUM>, a second end <NUM> and a central mounting portion <NUM> between the first and second ends <NUM>, <NUM>. Each rod <NUM> extends through the housing <NUM>. More specifically, the central mounting portion <NUM> of each rod <NUM> is mounted to the housing <NUM> by means of a bearing <NUM>. The first end <NUM> of the each rod <NUM> extends into the interior volume <NUM> of the housing <NUM> towards a central axis <NUM> of the housing <NUM>. The second end <NUM> is located external to the housing <NUM>, extending radially away from the central axis <NUM> of housing <NUM>. The first and second ends <NUM>, <NUM> of each rod <NUM> are free to move. The bearing <NUM> translates any movement from the first end <NUM> to the second end <NUM> of each rod <NUM> (and vice versa). The rods <NUM> are independent in that each rod <NUM> is not mechanically coupled to any of the other rods <NUM>. As such, the rods are independent and can move randomly relative to each other.

The rods <NUM> are distributed about of the housing <NUM> in both θ and z directions. The rods <NUM> are predominately located in the second portion <NUM> of the housing <NUM>. <FIG> depict the rods <NUM> as being uniformly distributed about the housing <NUM>, orientated perpendicular to the housing <NUM> and all of uniform dimensions such as length.

As can be seen from <FIG> which depicts one of the rods <NUM>, both the first and second ends <NUM>, <NUM> comprise enlarged regions 38a, 38b with thermally conductive surfaces 39a, 39b. The thermally conductive surfaces 39a located on the enlarged region 38a at the first end <NUM> facilitate absorbing thermal energy by thermal diffusion from the liquids <NUM>, <NUM> contained within the housing <NUM>. The absorbed thermal energy can conduct along the rod <NUM> to the second end <NUM>. The thermally conductive surfaces 39b located on the enlarged regions 38b at the second end <NUM> facilitate dissipating the thermal energy to the external surroundings of the cooling apparatus <NUM> through thermal diffusion. The thermally conductive surfaces 39a, 39b are made of the same material as the bulk of the rods <NUM>.

The rods <NUM> may comprise a protective coating <NUM> which covers all but the thermally conductive surfaces 39a, 39b. It will be appreciated the thermally conductive surfaces 39a, 39b may be made of a different material such as pure copper which has a high thermal conductivity.

The rods <NUM> depicted in <FIG>, further comprises thermally conductive protrusions <NUM> protruding from the thermally conductive surfaces 39b at the second end <NUM>. The thermally conductive protrusions <NUM> increase the surface area of the thermally conductive surfaces 39b and so increase the thermal energy dissipation capacity of the second end <NUM> of the rod <NUM>.

It will be appreciated the dimensions, design, and composition of the rods <NUM> can be optimised to achieve the desired thermal dissipation properties. For example, the length of the rods <NUM>, dimensions of the enlarged regions 38a, 38b, the thermally conductive surfaces 39a, 39b and or the inclusion of the thermally conductive protrusions <NUM> can be varied to increase or decrease the thermal dissipation properties of the rods <NUM>.

The rods <NUM> are configured to operate randomly relative to each other. It will be further be appreciated the dimensions, design and material composition of each rod <NUM> may vary. Variations in the rods <NUM> may contribute to the relative random movement of the rods <NUM>.

The housing <NUM> comprises a sealable inlet port <NUM> and a sealable outlet port <NUM>. The sealable inlet port <NUM> is located at a top end <NUM> of the housing <NUM>, through the second portion <NUM> of the housing <NUM> and provides a means for adding the first and second liquids <NUM>, <NUM> into the housing <NUM>. Similarly, the sealable outlet port <NUM> is located, at a base end <NUM> of the housing <NUM>, through the first portion <NUM> of the housing <NUM> and provides a means for draining the first and second liquids <NUM>, <NUM> from the housing <NUM>. In order to fill and maintain the housing <NUM> at a positive pressure, the first and second liquids <NUM>, <NUM> may be pumped to and from the housing <NUM> by a pumping system <NUM>.

<FIG> shows the cooling apparatus <NUM> of <FIG> in operation, in other words cooling the high temperature air <NUM>. The cooling apparatus <NUM> is a closed device such that the first and second liquids <NUM>, <NUM> are not added or removed during operation. The heat exchanging apparatus <NUM>, in other words the coiled pipe <NUM>, transfers heat to the first liquid <NUM>. As such, a portion of the first liquid <NUM> evaporates to form a first liquid vapour. The first liquid vapour takes the form of gaseous bubbles <NUM>. The gaseous bubbles <NUM> have a lower density than both the first liquid <NUM> and the second liquid <NUM>. As such, the gaseous bubbles <NUM> move in the positive z-direction, into the second portion <NUM> of the housing <NUM> and through the second liquid <NUM>. The thermal energy from the high temperature air <NUM> is converted into kinetic energy in the form of the motion of the gaseous bubbles <NUM>.

The interaction, in the form of relative motion and or thermal gradients, of the gaseous bubbles <NUM> and the second liquid <NUM> creates a fluid flow. More specifically, the fluid flow includes the flow of the first liquid <NUM>, second liquid <NUM> and gaseous bubbles <NUM>. For example, the fluid flow is depicted by the arrows in <FIG>. This fluid flow may be Laminar and or turbulent. The fluid flow induces the first end <NUM> of the rods <NUM> to move, oscillate and or vibrate. As such, the kinetic energy of the gaseous bubbles <NUM> is converted into mechanical energy. The Laminar fluid flow of the gaseous bubbles <NUM> may result in the gaseous bubbles <NUM> directly colliding with the first ends <NUM> of the rods <NUM>, deflecting the rods <NUM>. Furthermore, the turbulent fluid flow of the gaseous bubbles <NUM> and second liquid <NUM> may induce movement and or mechanical vibrations within the first ends <NUM> of the rods <NUM>.

Each gaseous bubble <NUM> dissipates kinetic and thermal energy. As a result, each gaseous bubble <NUM> will eventually condense to form a liquid bubble <NUM> of the first liquid <NUM>. The liquid bubbles <NUM> sink back towards the base end <NUM>, into the first portion <NUM> of the housing <NUM> as the density of the liquid bubbles <NUM> is greater than the density of the second liquid <NUM>. An advantage of the liquid bubbles <NUM> sinking back through the second portion <NUM> of the housing <NUM>, is the liquid bubbles <NUM> may further create fluid flows and induce movement and or mechanical vibrations within the rods <NUM>.

The motion induced in the first ends <NUM> of the rods <NUM> is transmitted by means of the bearing <NUM> to the second ends <NUM> of the rods <NUM>. The heat absorbed by the first ends <NUM> of the rods <NUM> conducts along the rods <NUM> to the second ends <NUM>. The mechanical and thermal energy at the second ends <NUM> of the rods <NUM> is dissipated to the surroundings of the cooling apparatus <NUM>. As such, the cooling apparatus <NUM> cools the high temperature air <NUM>. The resulting low temperature air <NUM> is circulated into the building <NUM> and cools the computer systems <NUM> of the data centre <NUM>.

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

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

As an additional or alternative embodiment, the distribution of the rods <NUM> about the housing <NUM> may be non-uniform. As another additional or alternative embodiment, the rods <NUM> may be orientated non-perpendicular to the housing <NUM>. As a further additional or alternative embodiment, the dimensions, design, material composition, distribution, and orientation of the rods <NUM> may be computationally optimised.

As an additional or alternative feature, the cooling apparatus <NUM> further comprises pellets <NUM>. As can be seen in <FIG>, the pellets <NUM> are located within the interior volume <NUM> of the cooling apparatus <NUM> suspended within the first and second liquids <NUM>, <NUM>. The pellets <NUM> move about the interior volume <NUM> of the housing <NUM> in response to the fluid flow created by the interaction of the gaseous bubbles <NUM> and the second liquid <NUM>. The pellets <NUM> collide with the rods <NUM> inducing further movement, or more specifically, mechanical vibrations within the rods <NUM>, in addition to the movement induced directly by the fluid flow. The density of the pellets <NUM> is between the density of the first and second liquids <NUM>, <NUM> such that the pellets <NUM> are not too heavy or buoyant when suspended within the first and second liquids <NUM>, <NUM>. Furthermore, the pellets <NUM> are chemically unreactive with the first liquid <NUM>, second liquid <NUM> and gaseous bubbles <NUM>. The pellets <NUM> are also preferably magnetically neutral. The dimensions and material composition of the pellets <NUM> may be optimised to achieve the desired interaction with the fluid flow.

As an additional or alternative embodiment, the cooling apparatus <NUM> of <FIG>, further comprises a condensing loop <NUM> with a condenser <NUM>. Instead of the gaseous bubbles <NUM> passively condensing once they have lost sufficient energy within the housing <NUM>, the condensing loop <NUM> actively condenses the gaseous bubbles <NUM>. More specifically, once the gaseous bubbles <NUM> have traversed through the second portion <NUM> of the housing <NUM>, the gaseous bubbles <NUM> pass through the condensing loop <NUM> where the condenser <NUM> actively cools the gaseous bubbles <NUM> such that they condense to liquid bubbles <NUM>. The liquid bubbles <NUM> are returned to the first portion <NUM> of the housing <NUM>. A condensing loop <NUM> may be advantageous if, for example, the cooling apparatus <NUM> is over heated such that the gaseous bubbles <NUM> accumulate at the top end <NUM> of the housing <NUM> and the level of the first liquid in the housing <NUM> decreases.

As another additional or alternative feature, the cooling apparatus <NUM> of <FIG> further comprises a sink <NUM> of the first liquid <NUM>. The sink <NUM> is connected to the housing <NUM> and maintains the level of the first liquid <NUM> within the first portion <NUM> of the housing <NUM>. As the first liquid <NUM> evaporates within the cooling apparatus <NUM>, this may induce non negligible changes in pressure and or volume within the cooling apparatus <NUM>. The sink <NUM> minimises any changes in pressure and or volume.

As another additional or alternative feature, the cooling apparatus <NUM> of <FIG> further comprises storage tanks <NUM>. Each storage tank <NUM> comprises a different liquid such as those listed in Table <NUM> and the storage tanks are connected to the pumping system <NUM>. The liquids may be compressed for storage within the storage tanks <NUM>. The pumping system <NUM> facilitates removing the first and second liquids <NUM>, <NUM> from the housing <NUM> to be stored within the respective storage tanks <NUM>. The pumping system <NUM> can also facilitate replacing the first and second liquids <NUM>, <NUM> with alternative combinations of liquids. As such, the combination of the first and second liquid <NUM>, <NUM> can be optimised according to the operation conditions of the cooling apparatus <NUM>. The process of removing and replacing the first and second liquids <NUM>, <NUM> according to the operation requirements may be automated by the pumping system <NUM>. As such the pumping system <NUM> may comprise sensors to monitor the cooling apparatus <NUM> and the surrounding conditions. Whilst <FIG> depicts two storage tanks <NUM> it will be appreciated there may be a plurality of storage tanks <NUM> offering numerous alternative combinations of first and second liquids <NUM>, <NUM>.

The process of heat transfer to the first liquid <NUM>, evaporation of the first liquid <NUM> to form gaseous bubbles <NUM>, mechanical and thermal energy transfer from the gaseous bubbles <NUM> to the energy dissipation member (in other words the rods <NUM>) and condensation of the gaseous bubbles <NUM> to form liquid bubbles <NUM> is repeated forming a cycle. The mechanical and thermal energy is continually dissipated by the cooling apparatus <NUM>.

A key advantage of the cooling system 15a is that it requires less electrical energy to operate. In the embodiment of <FIG>, electrical power is only required to operate the circulation fan <NUM>. The cooling system 15a does not comprise a compressor or a condenser. As such, the cooling system 15a cools the computer systems <NUM> of the data centre <NUM> using less electrical energy than conventional systems <NUM> known in the art. As such, the cooling system 15a is environmentally friendly. It is noted, the cooling apparatus <NUM> can operate without drawing any electrical power. As such, the cooling apparatus <NUM> may be considered a passive component.

<FIG> depicts an alternative cooling system 15b which may comprise the same preferable and optional features as the cooling system 15a as depicted in <FIG>.

However, instead of the circulation loop 6a of <FIG>, the heat transfer apparatus of the cooling system 15b of <FIG> takes the form of a circulation loop 6b sealed within which is a fluid <NUM>. The circulation loop 6b comprises pipes 17b which channel the fluid <NUM> to the computer systems <NUM>. Heat is transferred from the computer systems <NUM> to the fluid <NUM> within the circulation loop 6b.

The pipes 17b in the vicinity of the computer systems <NUM> act as a heat exchanging apparatus and may be arranged to maximise the heat transfer from the computer systems <NUM> to the fluid <NUM>. For example, the pipes 17b zigzag back and forth so as to take multiple passes by the computer systems <NUM>, increasing the time the fluid <NUM> is exposed to the computer systems <NUM> and so maximising the heat transferred to the fluid <NUM>.

A circulation pump 7b circulates the heated fluid <NUM> through the pipes 17b of the circulation loop 6b towards a cooling apparatus <NUM>. The cooling apparatus <NUM> cools the heated fluid <NUM> and the resulting cooled fluid <NUM> is circulated back towards the computer systems <NUM> to absorb more heat. The process of absorbing heat from the computer systems <NUM>, transferring the heat to the cooling apparatus <NUM> and dissipating the heat by means of the cooling apparatus <NUM> is repeated resulting in the continual cooling the computer systems <NUM>.

The fluid <NUM> sealed within the circulation loop 6b does not mix with air external to the circulation loop 6b such as air contained within the building <NUM>. The fluid <NUM> can be any suitable fluid such as a refrigerant known in the art.

An advantage of the circulation loop 6b is that the fluid <NUM> may be as chosen according to the operational parameters of the cooling system 15b, for example the operational temperature range. Whilst the fluid <NUM> of the circulation loop 6b could be air, in contrast to circulation loop 6a, the circulation loop 6b is not limited to circulating air. As such, the fluid <NUM> of the circulation loop 6b may have desirable thermal and chemical properties to enhance the cooling system 15b. Furthermore, it may be financially more favourable to operate with a particular fluid <NUM> instead of air. In particular, the fluid <NUM> of the circulation loop 6b may not demand relatively more expensive, higher pressure apparatus required for operating with air.

<FIG> depicts an alternative cooling system 15c which may comprise the same preferable and optional features as the cooling systems 15a, 15b depicted in <FIG>.

However, instead of the circulation loops 6a, 6b of <FIG> and <FIG>, the heat transfer apparatus of the cooling system 15c of <FIG> takes the form of a circulation loop 6c with a first loop <NUM> and a second loop <NUM>. The first loop <NUM> comprises a first fluid <NUM>. The first fluid <NUM> is sealed within the first loop <NUM>. Similarly, the second loop <NUM> comprises a second fluid <NUM>. The second fluid <NUM> is sealed within the second loop <NUM>. The first and second fluids <NUM>, <NUM> do not mix with each other nor air external to the circulation loop 6c. The first and second fluids <NUM>, <NUM> are circulated about the first and second loops <NUM>, <NUM> by circulation pumps 7c.

Heat from the computer systems <NUM> is transferred to the first fluid <NUM> of the first loop <NUM>. Similar to the second embodiment of <FIG>, pipes 17c of the first loop <NUM> located in the vicinity of the computer systems <NUM> act as a heat exchanging apparatus and may be arranged to maximise the heat transfer from the computer systems <NUM> to the first fluid <NUM>.

The first loop <NUM> transfers the heated first fluid <NUM> to a heat exchanging apparatus <NUM>. The heat exchanging apparatus <NUM> transfers heat from the first fluid <NUM> of the first loop <NUM> to the second fluid <NUM> of the second loop <NUM>. The second loop <NUM> transfers the heated second fluid <NUM> to a cooling apparatus <NUM> which cools the heated second fluid <NUM>. The resulting cooled second fluid <NUM> is circulated back within the second loop <NUM> to the heat exchanging apparatus <NUM> where it cools the heated first fluid <NUM>. Then, the cooled first fluid <NUM> is circulated back within the first loop <NUM> to computer systems <NUM> to repeat the cycle and reabsorb heat thereby continually cooling the computer systems <NUM>.

The first and second fluids <NUM>, <NUM> of the first and second loops <NUM>, <NUM> may be the same or different. Again, like the second embodiment of <FIG>, the first and second fluids <NUM>, <NUM> may be chosen according to the operation parameters of the cooling system 15c.

Advantageously, the cooling system 15c of <FIG> is particularly suited for retrofitting existing cooling systems known in the art with a cooling apparatus <NUM>. The first loop <NUM> of <FIG> may exist as part of cooling systems known in art. As such, when retrofitting, only the second loop <NUM> and cooling apparatus <NUM> needs to be introduced. This can save considerable expense and time.

It will be appreciated that the circulation loop 6c of <FIG> may additionally comprise a third loop and more generally a plurality of loops. Additional loops in conjunction with heat exchanging apparatus may help connect multiple data centres <NUM> and or multiple cooling apparatus <NUM> to the cooling system 15c.

<FIG> depicts a further alternative cooling system 15d which may comprise the same preferable and optional features as the cooling systems 15a, 15b, 15c depicted in <FIG>.

Instead of the circulation loops 6a, 6b, 6c of <FIG> and <FIG>, the heat transfer apparatus of the cooling system 15d of <FIG> takes the form of conductive members <NUM>, each conductive member <NUM> thermally connected at a first end <NUM> directly to the computer systems <NUM> and at a second end <NUM> to the cooling apparatus <NUM>. The second ends <NUM> of the conductive members <NUM> extend through the housing <NUM> into the interior volume <NUM> of the cooling apparatus <NUM>. As such the second ends <NUM> of the conductive members <NUM> are in direct thermal contact with the first and second liquids <NUM>, <NUM> within the cooling apparatus <NUM>. The conductive members <NUM> comprise a high conductive solid material such as pure copper.

In operation, heat is transferred or transported from the computer systems <NUM> of the data centre <NUM> to the cooling apparatus <NUM> by thermal diffusion along the conductive members <NUM>. The second ends <NUM> of the conductive members <NUM> act as the heat exchanging apparatus <NUM> of the cooling apparatus <NUM> transferring the heat to the first and second liquids <NUM>, <NUM> within the cooling apparatus <NUM>. The cooling apparatus <NUM> dissipates the heat maintaining a thermal gradient across the conductive members <NUM>. As such, heat is continually transferred to the cooling apparatus <NUM>, cooling the computer systems <NUM>.

Advantageously, the cooling system 15d of <FIG> requires even less control and maintenance than the cooling systems 15a, 15b, 15c depicted in <FIG>. There is no high temperature air <NUM> nor fluid <NUM>, <NUM>, <NUM> circulating about a circulation loop 6a, 6b, 6c minimising the number of moving parts as well as negating the need for a pumping system <NUM> and storage tanks <NUM>. The cooling system 15d of <FIG> provides a solid-state solution to transfer the heat from the computer systems <NUM> to the cooling apparatus <NUM> as relies simply of thermal diffusion across the conductive members <NUM>.

<FIG> depicts an alternative cooling system 15e which may comprise the same preferable and optional features as the cooling systems 15a, 15b, 15c, 15d depicted in <FIG>.

Instead of the circulation loops 6a, 6b, 6c of <FIG> and <FIG> or the conductive members <NUM> of <FIG>, the cooling system 15e of <FIG> is configured such that a separate component to act as the heat transfer apparatus to transfer heat from the computer systems <NUM> to the cooling apparatus <NUM> is not required.

As can be seen from <FIG>, the cooling apparatus <NUM> is located upon the roof of the building <NUM>. The first portion <NUM> of the housing <NUM> of the cooling apparatus <NUM> extends into the building <NUM> such that the first portion <NUM> is exposed to the high temperature air <NUM> within the building <NUM>.

The cooling system 15e operates by convection currents in the air contained within the building <NUM>. In operation, the heat from the computer systems <NUM> located on the floor of the building <NUM>, rises to the roof of the building <NUM>. The housing <NUM> of the cooling apparatus <NUM> acts as the heat exchanging apparatus <NUM> in that the high temperature air <NUM> transfers heat through the housing <NUM> to the first liquid <NUM> located within the housing <NUM>. The heat transferred to the cooling apparatus <NUM> is dissipated. As such, the high temperature air <NUM> is cooled and sinks back to the floor of the building <NUM> where it can absorb heat for the computer systems <NUM>. This process is repeated such that the computer systems <NUM> are continually cooled.

It will be appreciated that the operation of the cooling system 15e and specifically, the heat dissipation capacity, can be modified by varying the exposure of the cooling apparatus <NUM> to the high temperature air <NUM> within the building <NUM>. In other words, if a greater proportion of the cooling apparatus <NUM> extends within the building <NUM> such that a greater proportion of the housing <NUM> is in thermal contact with the high temperature air <NUM>, then the cooling apparatus <NUM> will absorb more heat. The relative thermal exposure of the cooling apparatus is a parameter that can be optimised according to the characteristics of the specific cooling system 15e.

<FIG> 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 in <FIG>.

The cooling system 15f of <FIG> combines the cooling system 15b of <FIG> with the cooling system 15d of <FIG>.

As can be seen from <FIG>, a cooling apparatus <NUM> is located upon the roof of the building <NUM> like the cooling system 15b of <FIG>. The housing <NUM> is exposed to high temperature air <NUM> from the building <NUM>. The housing <NUM> acts as a heat exchanging apparatus as heat is transferred from the high temperature air <NUM> to the cooling apparatus <NUM>.

In addition, the cooling system 15f comprises heat transfer apparatus in the form of a circulation loop 6f sealed within which is a fluid <NUM>. A portion of the circulation loop 6f is located within the building <NUM> and acts as an additional heat exchanging apparatus. The fluid <NUM> of the circulation loop 6f absorbs heat from the high temperature air <NUM>. The heated fluid <NUM> is channelled within the cooling apparatus <NUM> which cools the heated fluid <NUM>.

The cooling system 15f comprises two mechanisms to transfer heat from the high temperature air <NUM> to the cooling apparatus <NUM>, namely convection and a circulation loop 6f. As such, the cooling system 15f advantageously has an improved efficiency of the cooling systems 15b, 15d of <FIG> and <FIG>.

<FIG> depicts an alternative cooling system <NUM> which may comprise the same preferable and optional features as the cooling systems 15a, 15b, 15c, 15d, 15e, 15f depicted in <FIG>.

Instead of the transferring heat from the computer systems <NUM> housed within a building <NUM> to a cooling apparatus <NUM>, the building <NUM> itself is configured to be a cooling apparatus <NUM>. As such, a heat transfer apparatus is not required. The building <NUM> houses a first liquid <NUM> and a second liquid <NUM>. The computer systems <NUM> and first liquid <NUM> are located in a first portion <NUM> of the building <NUM>, towards the base of the building <NUM>, and the second liquid <NUM> locates within a second portion <NUM> of the housing <NUM>, above the first liquid <NUM>. The computer systems <NUM> comprise a fluid tight casing <NUM> as the computer systems <NUM> are immersed within the first liquid <NUM>. The fluid tight casing <NUM> as acts as an interface between the computer systems <NUM> and the first liquid <NUM>. As such, in this embodiment the heat exchanging apparatus <NUM> of the cooling system <NUM> is the fluid tight casing <NUM>. The building <NUM> further comprises a plurality of independent energy dissipation members <NUM> such as rods <NUM>.

In operation, the building <NUM> is fluidly sealed such that the first and second liquids <NUM>, <NUM> do not leak from the building <NUM>. The building <NUM> operates as a cooling apparatus <NUM> in the same way as the cooling apparatus <NUM> of <FIG>. The first liquid <NUM> evaporates to form gaseous bubbles <NUM> which rise through the building <NUM> and transfers kinetic and thermal energy to the rods <NUM>. The rods <NUM> transmit the motion and conduct the thermal energy induced by the gaseous bubbles <NUM> from the first to second ends <NUM>, <NUM> and dissipate the energy to the external surroundings of the building <NUM>.

Advantageously, the cooling system <NUM> is simplified as does not require the heat transfer apparatus to transfer heat from the computer systems <NUM> to a cooling apparatus <NUM> as the computer systems <NUM> are located within the cooling apparatus <NUM>.

The cooling systems 15a, 15b, 15c, 15d, 15e, 15f, <NUM> of <FIG> can cool the high temperature air <NUM> to the surrounding temperature, for example <NUM>. However, these cooling systems 15a, 15b, 15c, 15d, 15e, <NUM>, 15f cannot cool the high temperature air <NUM> below the surrounding temperature, <NUM>. If the air entering the cooling apparatus <NUM> was the same temperature as the surroundings, there would be no thermal gradients within the cooling apparatus <NUM> and heat would not transfer from the air to the first liquid <NUM>.

<FIG> depicts an alternative cooling system <NUM> which may comprise the same preferable and optional features as the cooling systems 15a, 15b, 15c, 15d, 15e, 15f, <NUM> depicted in <FIG>.

The cooling system <NUM> of <FIG> is similar to the vapour-compression refrigeration system depicted <NUM> of <FIG>. However, in contrast to <FIG>, the refrigeration loop <NUM> of <FIG> comprises a cooling apparatus <NUM> instead of a condenser <NUM>. The refrigeration loop <NUM> is the heat transfer apparatus.

The cooling system <NUM> of <FIG> operates in the same way as the cooling system <NUM> of <FIG>. However, the cooling apparatus <NUM> condenses the hot compressed gaseous working fluid <NUM> back to a liquid instead of a conventional condenser <NUM>.

Advantageously, the cooling system <NUM> can cool high temperature air <NUM> to a temperature below ambient temperature without the need to power a condenser. As such, the cooling system <NUM> of <FIG> is cheaper to operate and more environmentally friendly than the vapour-compression refrigeration system <NUM> known in the art.

<FIG> depicts an alternative cooling system 15i which may comprise the same preferable and optional features as the cooling systems 15a, 15b, 15c, 15d, 15e, 15f, <NUM>, <NUM> depicted in <FIG>.

The cooling system 15i of <FIG> is a combination of the cooling systems 15b, <NUM> of <FIG> and <FIG>.

The cooling system 15i of <FIG> comprises circulation loop 6i and a refrigeration loop 10i. Both the circulation loop 6i and the refrigeration loop 10i are the heat transfer apparatus. The circulation fan 7i circulates high temperature air <NUM> from a building <NUM> about the circulation loop 6i to an evaporator <NUM>. However, in contrast to the embodiment of <FIG>, the high temperature air <NUM> is first channelled through the cooling apparatus 16i before it reaches the evaporator <NUM>. The high temperature air <NUM> is partially cooled by the cooling apparatus 16i. After which, the resulting air is circulated to the evaporator <NUM> where it is further cooled by the refrigeration loop <NUM>.

The cooling apparatus 16i is also a component of the refrigeration loop 10i of <FIG>. As such, the cooling apparatus 16i cools both the high temperature air <NUM> of the circulation loop 6i and the working fluid <NUM> of the refrigeration loop 10i. The cooling apparatus 16i comprises two heat exchanging apparatus <NUM>, in the form of a first coiled pipe <NUM> and a second coiled pipe <NUM>. A first coiled pipe <NUM> forms part of the circulation loop 6i and channels high temperature air <NUM> through the cooling apparatus 16i. A second coiled pipe <NUM> forms part of the refrigeration loop 10i and channels working fluid <NUM> through the cooling apparatus 16i. The high temperature air <NUM> and working fluid <NUM> do not mix within the cooling apparatus 16i and more generally the cooling system 15i.

It will be appreciated that thermal capacity of the cooling apparatus 16i is optimised, so that it is sufficiently large to cool both the high temperature air <NUM> and the working fluid <NUM>. More specifically, the cooling apparatus 16i may be larger and have different first and second fluids <NUM>, <NUM> in comparison to the cooling systems 15b, <NUM> of <FIG> and <FIG>.

<FIG> depicts an alternative cooling system 15j which may comprise the same preferable and optional features as the cooling systems 15a, 15b, 15c, 15d, 15e, 15f, <NUM>, <NUM>, 15i depicted in <FIG>.

The cooling system 15j of <FIG> comprises a sealed refrigeration loop 10j which contains a working fluid 11j. In the embodiment of <FIG>, the working fluid 11j also acts as first liquid <NUM> of a cooling apparatus 16j.

The refrigeration loop 10j comprises an evaporator 8j located in the building <NUM> of the data centre <NUM>. The evaporator 8j transfers heat from high temperature air 5j (for example <NUM>) within the building <NUM> to the working fluid 11j of the refrigeration loop 10j inducing a phase change from a liquid to a gas.

The gaseous working fluid 11j circulates to and accumulates in a first chamber <NUM>. The first chamber <NUM> is fluidly connected to a second chamber <NUM>. Located between the first and second chamber <NUM>, <NUM> is a compressor 12j and then a relief valve <NUM>. The compressor 12j compresses the gaseous working fluid 11j to a hot liquid working fluid 11j with a temperature, for example, of <NUM> to <NUM>. The relief valve <NUM> releases the hot liquid working fluid 11j into the second chamber <NUM>. The relief valve <NUM> controls the flow and pressure of the hot liquid working fluid 11j entering the second chamber <NUM>. The working fluid 11j is compressed before entering the second chamber <NUM> to increase the heat capacity.

The second chamber <NUM> comprises a second liquid <NUM>. The second liquid <NUM> has a lower density but higher boiling point than the liquid working fluid 11j. As the hot liquid working fluid 11j enters the second chamber <NUM> and mixes with the second liquid <NUM>. The hot liquid working fluid 11j decompresses to a gas and bubbles up through the second chamber <NUM> dissipating energy to independent energy dissipating members 31j extending through the second chamber <NUM>, as described in the in the context of the cooling apparatus <NUM> of the first to ninth embodiments of <FIG>. As such, the working fluid 11j acts as the first liquid <NUM>.

The gaseous working fluid 11j is cooled to, for example, to <NUM>. The cooled gaseous working fluid 11j is siphoned off the second chamber <NUM> and further circulated about the refrigeration loop 10j where it is compressed by another compressor 12j increasing the temperature to, for example <NUM>. The compressors 12j may also act as pumps to assist with circulating the working fluid 11j about the refrigeration loop 10j. The compressed working fluid 11j is circulated through a coiled pipe 26j extending through the second chamber <NUM>. The coiled pipe <NUM> acts as a heat exchanging apparatus and transfers heat from the compressed working fluid 11j to the fluids within the second chamber <NUM> thereby further cooling the working fluid 11f.

The cooled working fluid 11f (<NUM>) condenses to a liquid and is circulated back to the building <NUM> via an expansion valve 14j. The expansion valve 14j reduces the pressure of the cooled working fluid 11f, further reducing the pressure to, for example -<NUM>. The cold (-<NUM>) uncompressed liquid working fluid 11f is recirculated into the evaporator 8j where, by means of thermal diffusion, heat again transfers from the high temperature air 5j to the working fluid 11j. The cycle repeats continually cooling the high temperature air 5j of the building <NUM> to below ambient temperature.

The housing 18j of the cooling apparatus 16j of <FIG> comprises the combination of the first chamber <NUM>, the second chambers <NUM> and pipes <NUM> forming the refrigeration loop 10j. The first liquid <NUM> is also the working fluid 11j and located throughout the refrigeration loop 10j. This embodiment demonstrates the housing 18j of the cooling apparatus 16j does not have to take the form of a unitary chamber and may more generally comprises multiple chambers in combination with connecting pipes. Advantageously, the housing <NUM> comprising multiple chambers can provide greater flexibility when designing an appropriate cooling apparatus <NUM> for a specific cooling system <NUM>.

Furthermore, this embodiment also demonstrates the working fluid 11j of a refrigeration loop 10j may also act as the first liquid <NUM> of a cooling apparatus 16j. Advantageously, this obviates the need for a cooling system <NUM> to comprise three fluids, namely a working fluid, first liquid and a second liquid when it can operate with two fluids.

As an additional feature, the refrigeration loop 10j of <FIG> may comprise a separator <NUM>. The cooled working fluid 11j siphoned off from the second chamber <NUM> passes through the separator <NUM> before being further circulated about the refrigeration loop 10j. The separator <NUM> separates any residual second liquid <NUM> mixed with the working fluid 11j exiting the second chamber <NUM>. The separated second liquid <NUM> is channelled back into the second chamber <NUM> by means of a drain <NUM>. The separator <NUM> ensures the second liquid <NUM> is confined to the second chamber <NUM> and only the working fluid 11j is circulated about the refrigeration loop 10j.

The separator <NUM> is depicted in <FIG> as a separate component of the refrigeration loop 10j, yet it will be appreciated the separator <NUM> may also take the form as an integral component of the compressor 12j located at the exit of the second chamber <NUM>.

As a further additional feature, the cooling system 15j of <FIG> may comprise a circulation fan 7j to draw high temperature air 5j into and through the evaporator 8j. Alternatively, the evaporator 8j may comprise an integral circulation fan to draw high temperature air 5j into and through the evaporator 8j.

The cooling systems <NUM> of <FIG> are described as cooling a data centre <NUM> and specifically, computer systems <NUM>, within a building <NUM>. It will be appreciated that the cooling systems <NUM> are not limited to cooling a data centre <NUM> and may be employed to cool any suitable body such as a heat source or building. For example, the cooling systems <NUM> may be employed to cool an office building or even a chiller room for chilled food products.

<FIG> shows a flow chart for a method of manufacturing the cooling apparatus <NUM>. The method comprises: providing a housing (S1001); providing a first and second liquid located within the housing, the first liquid having a higher density and lower boiling point than the second liquid (S1002); providing a heat transfer apparatus to transfer heat to the first liquid to evaporate the first liquid to form a first liquid vapour (S1003); and providing a plurality of independent energy dissipating members that extend through the housing, wherein the independent energy dissipating member move in response to a fluid flow created by the interaction of the first liquid vapour and second liquid, and transfer heat to a volume external to the housing.

In addition, the method of manufacturing the cooling apparatus <NUM> may optionally comprise characterising a body which is to be cooled, such as a data centre <NUM>. For example, this may include characterising properties such as the temperature of the body without any cooling, a target temperature of the body with cooling, the temperature variability of the body, the dimensions, shape, composition, location and accessibility of the body.

As a further addition, the method of manufacturing the cooling apparatus <NUM> may optionally comprise utilising the characteristics of the body to determine the optimum parameters of a cooling apparatus <NUM>. For example, this optimisation process may include determining: the dimensions and shape of the cooling apparatus <NUM>; the volume, relative ratio and chemical composition of the first and second liquids <NUM>, <NUM>; the distribution, orientation, dimensions, design and material composition of the rods <NUM>; if pellets <NUM> are required, if a condensing loop <NUM> is required; if a sink <NUM> is required; if storage tanks <NUM> are required; the form of the heat exchanging apparatus <NUM>, for example if multiple coiled pipes <NUM> are required; and how to cooling apparatus <NUM> is to be integrated into a cooling system. As an example 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 of the body, the greater required cooling capacity of the cooling apparatus <NUM>. When choosing the first and second liquids <NUM>, <NUM> factors such as the heat capacity, relative density and relative boiling points are key considerations. It is advantageous to optimise the cooling apparatus <NUM> as this ensures the cooling apparatus <NUM> can operate, in other words, the body will provide enough heat to evaporate any quantity of the first liquid <NUM>. Furthermore, the optimisation ensures the cooling apparatus <NUM> can operate efficiently.

A method of manufacturing a cooling system <NUM> comprises providing a cooling apparatus <NUM> in accordance with the flow chart depicted in <FIG>, as described above, and providing a body, such as a data centre <NUM> which is to be cooled.

As an additional or alternative feature, the method of manufacturing a cooling system <NUM> may optionally comprise providing a heat transfer apparatus to transfer heat from the body to the cooling apparatus <NUM>. The heat transfer apparatus may take the form of one or more circulation loops <NUM> in conjunction with a circulation fan <NUM> or conductive members <NUM>. In addition, or alternatively, the cooling apparatus <NUM> may be located above the body such that convection transfers heat from the body to the cooling apparatus <NUM>.

As a further additional or alternative feature, the method of manufacturing a cooling system <NUM> may optionally comprise providing a refrigeration loop <NUM>. The refrigeration loop <NUM> operates a thermodynamic cycle known in the art to cool a working fluid <NUM> below ambient temperature.

The cooling systems <NUM> disclosed herein have numerous advantages. Various advantageous of each cooling system <NUM> have been presented. In general, the cooling systems <NUM> all comprises a cooling apparatus <NUM> which passively dissipates heat. The cooling apparatus <NUM> can operate without drawing electrical power and so is financially favourable and environmentally friendly.

Advantageously the cooling apparatus <NUM> can be incorporated into numerous cooling systems <NUM>. For example, the cooling apparatus <NUM> can cool air or a fluid in a circulation loop <NUM>. Furthermore, the cooling apparatus <NUM> can be retrofitted to existing cooling systems such as a vapour-compression refrigeration system by replacing the condenser. In addition, the cooling apparatus <NUM> is suitable for a cooling system <NUM> comprising a circulation loop <NUM> and refrigeration loop <NUM>. The cooling apparatus <NUM> can cool both the fluid in the circulation loop <NUM> and the working fluid <NUM> in the refrigeration loop <NUM>. Such cooling systems <NUM> are capable of cooling below ambient temperature.

The cooling apparatus <NUM> does not rely on conventional thermodynamic cycles, but instead provides an alternative mechanism for dissipating heat by utilising a phase change of the first liquid <NUM> to create fluid flows and the subsequent interaction with the rods <NUM>. The cooling apparatus <NUM> has minimal moving components, reducing the amount of maintenance that may be required and maximising the lifetime of the device.

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

The cooling apparatus <NUM> is customisable as the rods <NUM>, and specifically the conductive surfaces <NUM> and conductive protrusions <NUM>, can be optimised for a specific cooling system <NUM>.

A cooling apparatus is disclosed. The cooling apparatus comprises a housing, a first liquid and a second liquid located within the housing. The first liquid has a higher density and lower boiling point than the second liquid. The cooling apparatus further comprises a heat exchanging apparatus to transfer heat to the first liquid to evaporate the first liquid to form a first liquid vapour. The cooling apparatus also comprises a plurality of independent energy dissipating members that extend through the housing. These members move in response to a fluid flow created by the interaction of the first liquid vapour and the second liquid and transfer heat to a volume external to the housing. The cooling apparatus can cool a body whilst drawing minimal or even no electrical power. As such the cooling apparatus is environmentally friendly and cheaper to operate.

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

Claim 1:
A cooling apparatus (<NUM>) comprising:
a housing (<NUM>);
a first liquid (<NUM>) and a second liquid (<NUM>) located within the housing (<NUM>),
a heat exchanging apparatus (<NUM>) to transfer heat to the first liquid (<NUM>) to evaporate a quantity of the first liquid (<NUM>) to form a first liquid vapour (<NUM>); and
a plurality of independent energy dissipating members (<NUM>) that extend through the housing (<NUM>), characterized in that the first liquid (<NUM>) has a higher density and lower boiling point than the second liquid (<NUM>); and
wherein the independent energy dissipating members (<NUM>) move ir response to a fluid flow created by the interaction of the first liquid vapour (<NUM>) and the second liquid (<NUM>) and transfer heat to a volume external to the housing (<NUM>).