GB2501250A

GB2501250A - Metal cabinet for electrical apparatus with containers of phase change material for temperature control

Info

Publication number: GB2501250A
Application number: GB1206623.9A
Authority: GB
Inventors: Anthony Richard John Hume; Laurence Alfred Bell
Original assignee: CREACTIVE DESIGN ENGINEERING Ltd
Current assignee: CREACTIVE DESIGN ENGINEERING Ltd
Priority date: 2012-04-16
Filing date: 2012-04-16
Publication date: 2013-10-23
Also published as: GB2504562A; GB201206623D0; GB201302136D0; GB2504562B

Abstract

A metal cabinet 10 for containing electrical apparatus and assemblies includes a roof (14, Fig 2), walls (12a, 12b, Fig 3) and at least one closure 16a, 16b which define an interior space (25, Fig 4)) of the cabinet 10. The interior space (25, Fig.4) of the cabinet 1 is provided with at least one container (28, Fig.3) which contains a phase change material (PCM). The PCM is selected to have a desired melting point such that it is able to absorb heat energy and maintain the temperature of the interferer space below a predetermined maximum. The container of PCM (28, Fig.3) may be mounted to an interior face of a wall, closure or roof of the cabinet within a recess. The cabinet 10 may be provided with a plurality of containers of PCM wherein the phase change temperatures of the containers are different. The external faces of one or more walls or closures may be provided with louver panels 20.

Description

Improved Cabinet The present invention relates to improvements in cabinets and particularly, though not exclusively, to metal cabinets which are intended to contain electrical apparatus and assemblies utilised fbr the control and operation of rail transport infrastructure. The cabinets of the present invention may also be utilised for the housing of telecommunications equipment.

Such infrastructure may include, for example, signal apparatus, rail points, power distribution and the like. The cabinets are typically made from metal and have at least one door which is openable to allow access to the interior of the cabinet.

So as to prevent the electrical equipment within the cabinet overheating, for example due to heat being generated internally by the equipment within the cabinet and/or by solar radiation, the cabinet may typically be provided with vents to allow hot air to exit the cabinet and cooler ambient air to enter the cabinet. While such vents arc beneficial during summer months, they can cause problems during winter months by allowing the ingress of snow and moisture which can damage the electrical apparatus and assemblies.

The present invention seeks to address these problems.

According to a first aspect of the present invention there is provided a metal cabinet for containing electrical apparatus and assemblies, the cabinet including a roof walls and at least one closure which define an interior space of the cabinet, wherein the interior space of the cabinet is provided with at least one container which contains a phase change material.

The phase change temperature of the phase change material is chosen such that it is able to absorb heat energy and thereby maintain the temperature of the interior space below a predetermined maximum. The heat energy may emanate from the electrical apparatus within the cabinet. Alternatively, or indeed additionally, the heat energy may be received externally, for example from incident solar radiation and ambient air temperature. The phase change material can also act to keep the temperature of the interior space above a predetermined minimum by releasing heat energy, for example over night as the ambient air temperature reduces.

Tn one embodiment, the cabinet may contain electrical apparatus and assemblies which are utilised for the control and operation of rail infrastructure. Alternatively, the cabinet may contain electrical apparatus and assemblies which are utilised for telecommunications.

TO The container of phase change material is preferably mounted to an interior face of either a wall or closure of the cabinet or an interior face of the roof of the cabinet. In a preferred embodiment the container of phase change material is preferably mounted to a recess in an interior face of either a wall or closure of the cabinet or a recess an interior face of the roof of the cabinet. Preferably the thickness of the container is less T5 than or equal to the depth of the recess. As such, encroachment of the container into the interior space of the cabinet intended to receive the electrical apparatus and assemblies.

The cabinet may be provided with a plurality of container of phase change material.

Optionally the external faces of one or more of the walls or closures may be provided with louver panels. The lover panels are mounted to said exterior faces and thus do not define apertures in the aforementioned walls or closures.

According to a second aspect of the present invention there is provided a method of limiting the temperature of the interior space of a closed metal cabinet containing electrical apparatus and assemblies, the method comprising the steps of: selecting a phase change material having a desired melting point; providing a container which contains a quantity of said phase change material; and placing said container within said interior space.

An embodiment of the present invention will now be described with reference to the accompanying drawings in which; Figure 1 shows a perspective view of a cabinet according to the present invention; Figure 2 shows a side view of the cabinet of figure 1; Figure 3 shows the cross-sectional view indicated by arrows A-A of figure 2; Figure 4 shows the cross-sectional view indicated by arrows B-B of figure 2; Figure 5 shows an exploded view of the cabinet; Figure 6 shows a perspective view of a door of the cabinet; Figure 7 shows an end view of the door; and Figure 8 shows the cross-sectional view indicated by arrows A-A of figure 7.

Referring to the drawings there is shown a cabinet generally designated 10. The cabinet 10 includes a pair of opposed side walls 12a,12b, a pitched roof 14 and closures in the form of two pairs of doors 16a,16b,18a,18b. The doors 16a,16b,18a,18b are hinged to the side walls 12a,12b so that they can open outwardly to permit access to the interior of the cabinet 10. While in the embodiment shown the cabinet 10 has two pairs of doors 1 6a, 1 6b, 1 8a, 1 8b it will be appreciated that other cabinet configurations are possible. For example, the cabinet 10 may be provided with only one pair of doors 16a,16b and a solid wall in place of the second pair of doors. Alternatively, the closures of the cabinet 10 may be defined by removable panels.

In the embodiment shown, one of the door pairs 16a,16b and one of the side walls 12a are provided with external louvers 20. In the embodiment shown, the louvers 20 are connected to the doors 16a,16b and side wall 12a by the provision ofhoolc formations 22 on each louver 20 and complementary slots 24 in the doors 16a,16b and side wall 12a. It will be appreciated that other methods of attaching the louvers 20 may be employed. For example, the louvers 20 may be attached directly to the external faces of the doors 16a,16b and side wall 12a by welding. Alternatively, a plurality of louvers 20 may be mounted to frames which, in turn, are mounted to the doors 16a,16b and sidewall 12a.

The cabinet 10 is further shown with additional roof panels 26 which are similar in form to the louvers 20 and define a second, so called "safari roof' over the pftched roof The presence of the louvers 20 and additional roof panels 26 are optional and are used to reduce the effect of solar radiation heating the cabinet. The presence of louvers 20 on one pair of doors 16a,16b and one side wall 12a are shown by way of example only. Depending upon the physical location of the cabinet 10 and thus the solar radiation which the cabinet 10 is expected to be subjected to, the cabinet 10 may require louvers 20 on more sides, louvers 20 on fewer sides, or no louvers 20 at all.

The doors 16a,16b,18a,18b, side walls 12a,12b and pitched roof 14 of the cabinet 10 define an interior space 25 which, in use, electrical equipment and assemblies can be placed. For the purposes of illustrating the present invention the interior space 25 is shown to be empty. It will however be appreciated that, in use, the interior space 25 will be provided with support surfaces such as, for example, brackets and shelves, configured to support electrical equipment and assemblies.

So as to prevent the interior temperature of the cabinet 10 rising above a desired upper limit, due to incident solar radiation and/or heat generated internally by the electrical equipment, the doors 16a,16b,18a,18b of the cabinet 10 are provided with a plurality of Phase Change Material (PCM) blocks 28. The PCM blocks 28 each comprise a container within which there is provided a quantity of phase change material. The phase change material is configured so as to store and release thermal energy during changes in material phase, i.e. melting and freezing. The material absorbs thermal energy from it's surrounding environment when it melts, and releases the energy when it freezes. The composition of the phase change material can be tailored so that it melts at a desired temperature. Depending upon the specific application, the phase change material may be a salt hydrate or an organic material such as a wax or an oil.

Tn the embodiment shown, the PCM blocks 28 are fitted to a recess 30 defined within each door 16a,16b,18a,18b. As such, the blocks 28 do not encroach into the main interior space 25 of the cabinet 10. In the embodiment shown, the PCM blocks 28 fill the recesses within each door 16a,16b,18a,18b. It will be appreciated that the number and position of the blocks 28 is wholly dependent upon the conditions that are likely to be experienced by the cabinet in situ. For example, one or both of the interior surfaces of the walls 12a.12b may be provided with PCM blocks 28, as may the

S

interior surfaces of the pitched roof 14. The blocks 28 may further be fitted around specific items of electrical equipment within the interior space 25.

While arrays of individual blocks 28 are shown in the figures, it will be appreciated that PCM liner panels which conform either wholly or partially to the shape of the interior faces of the doors I 6a, I 6b,I 8a,I 8b, walls I 2a, I 2b and roof 14.

In use, the phase change temperature of the PCM material is chosen such that the material absorbs heat both generated internally by the electrical equipment and externally resulting from solar radiation and thereby maintains the temperature of the interior space 25 below a predetermined maximum. It will be appreciated that the chosen phase change temperature of PCM material will depend upon a number of factors including, for example, the desired maximum interior space temperature for the cabinet, the heat energy generated by the electrical equipment within the interior space, the ambient air temperature at the location of the cabinet, and the incident solar radiation that the location of the cabinet.

Depending upon actual measured and/or estimated values for the above, the number, location and characteristics of the phase change material blocks for a given cabinet can be determined. It will be appreciated that blocks having differing phase change temperatures may be used within a cabinet.

A further advantage of the phase change material blocks is their ability to release energy. This characteristic can by utilised to maintain the temperature of the interior space above a predetermined minimum as the temperature outside the cabinet reduces, for example ovemight.

The need for vent apertures as found in existing cabinets is mitigated and thus addresses the aforementioned problems relating to the ingress of snow and moisture.

Claims

Claims 1. A metal cabinet for containing electrical apparatus and assemblies, the cabinet including a rooL walls and at least one closure which define an interior space of the cabinet, wherein the interior space of the cabinet is provided with at least one container which contains a phase change material.
2. A metal cabinet as claimcd in claim 1 whercin the cabinet contains clcctrical apparatus and asscmblics which are utilised for thc control and operation of rail infrastructure.
3. A metal cabinet as claimed in claim I wherein the cabinet contains electrical apparatus and assemblies which are utilised for telecommunications.
4. A metal cabinet as claimed in any preceding claim wherein the container of phase change material is mounted to one of an interior face of either a wall or closure of thc cabinet and an intcrior facc of the roof of the cabinet.
5. A metal cabinet as claimed in claim 4 wherein the container of phase change matcrial is mounted to a reccss in one of an intcrior face of either a wall or closure of thc cabinet and a recess an interior facc of thc roof of the cabinct.
6. A metal cabinet as claimed in claim 5 wherein the thickness of the container is less than or equal to the depth of the recess.
7. A metal cabinet as claimed in any preceding claim wherein the cabinet is provided with a plurality of containers of phase change material.
8. A metal cabinet as claimcd in claim 7 wherein the phase change tcmpcraturcs of the plurality of contaillers of phase change material are different.
9. A metal cabinct as claimed in any prcccding claim whcrcin the cxtcrnal faccs of onc or more of thc walls or closurcs arc providcd with louver pancls.
10. A method of limiting the temperature of the interior space of a closed metal cabinet containing electrical apparatus and assemblies, the method comprising the steps of selecting a phase change material having a desired melting point; providing a container which contains a quantity of said phase change material; and placing said container within said interior space.