GB2575619A - Modular skirt, support structure, housing for IT equipment, and ventilation system - Google Patents
Modular skirt, support structure, housing for IT equipment, and ventilation system Download PDFInfo
- Publication number
- GB2575619A GB2575619A GB1806196.0A GB201806196A GB2575619A GB 2575619 A GB2575619 A GB 2575619A GB 201806196 A GB201806196 A GB 201806196A GB 2575619 A GB2575619 A GB 2575619A
- Authority
- GB
- United Kingdom
- Prior art keywords
- air
- support structure
- equipment
- housing
- skirt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000009423 ventilation Methods 0.000 title claims description 48
- 238000012545 processing Methods 0.000 claims description 8
- 239000003570 air Substances 0.000 description 152
- 238000001816 cooling Methods 0.000 description 29
- 239000012080 ambient air Substances 0.000 description 14
- 238000009434 installation Methods 0.000 description 5
- 238000012423 maintenance Methods 0.000 description 5
- 238000013022 venting Methods 0.000 description 3
- 238000004378 air conditioning Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 2
- 230000001010 compromised effect Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000003595 mist Substances 0.000 description 2
- 238000005057 refrigeration Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000003028 elevating effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 230000037361 pathway Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/20009—Modifications to facilitate cooling, ventilating, or heating using a gaseous coolant in electronic enclosures
- H05K7/20136—Forced ventilation, e.g. by fans
- H05K7/20145—Means for directing air flow, e.g. ducts, deflectors, plenum or guides
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/14—Mounting supporting structure in casing or on frame or rack
- H05K7/1485—Servers; Data center rooms, e.g. 19-inch computer racks
- H05K7/1497—Rooms for data centers; Shipping containers therefor
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/20709—Modifications to facilitate cooling, ventilating, or heating for server racks or cabinets; for data centers, e.g. 19-inch computer racks
- H05K7/20718—Forced ventilation of a gaseous coolant
- H05K7/20745—Forced ventilation of a gaseous coolant within rooms for removing heat from cabinets, e.g. by air conditioning device
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/20—Modifications to facilitate cooling, ventilating, or heating
- H05K7/20709—Modifications to facilitate cooling, ventilating, or heating for server racks or cabinets; for data centers, e.g. 19-inch computer racks
- H05K7/20836—Thermal management, e.g. server temperature control
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K7/00—Constructional details common to different types of electric apparatus
- H05K7/14—Mounting supporting structure in casing or on frame or rack
- H05K7/1485—Servers; Data center rooms, e.g. 19-inch computer racks
- H05K7/1488—Cabinets therefor, e.g. chassis or racks or mechanical interfaces between blades and support structures
- H05K7/1489—Cabinets therefor, e.g. chassis or racks or mechanical interfaces between blades and support structures characterized by the mounting of blades therein, e.g. brackets, rails, trays
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Computer Hardware Design (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Cooling Or The Like Of Electrical Apparatus (AREA)
Abstract
A housing for IT equipment, preferably a shipping container (figs 4, 5), comprises an air-mixing chamber 3 with a first air inlet 1, the chamber connected to a IT system space housing IT equipment 5 via a fan (4) arranged to force air from the chamber 3 to the space 5. A support structure (20 fig 4) for IT devices 6 also provides exhaust ducting from the equipment above and an air inlet for air passage 25. The support structure is arranged so that a fan of the IT device is directed vertically downwards. A modular skirt for an IT device is configured to surround a portion of the IT device and to extend radially outwardly from the IT device. The skirt is preferably arranged between an array of IT devices to stop air bypassing the devices and support structure ducting. The air passage has at one end a variable-resistance element 11 between it and the air-mixing chamber 3, and preferably at another end an outlet 7. Air can flow through the IT equipment in the system space 5, through the supports and skirts to the passageway, and back into the air-mixing chamber, and/or the outlet. (figures 6 to 8 show fresh air, attemperation or recirculation modes respectively.) (figures 9 and 10 show how IT equipment may be arrayed) The IT equipment maybe preferably be racked to either side of the shipping container, with a central walkway between.
Description
Modular skirt, Support Structure, Housing for IT Equipment, and Ventilation System
The invention relates to a modular skirt for an IT device, a support structure for supporting one or more IT devices, a housing for containing IT equipment, and a ventilation system for providing a stream of controlled-temperature air. In particular, the invention relates to a ventilation system for cooling IT equipment in a system space such as a data centre.
Background
There is a need for cost-effective, low-energy cooling of buildings and facilities such as system spaces in the Information Technology (IT) sector such as data centres, server rooms and other spaces housing IT equipment. Such IT equipment or apparatus, which may include computing, telecommunications and other types of equipment, generates heat during normal operation and needs to be appropriately cooled, conventionally by air cooling.
It is desirable to control the psychrometric conditions of air delivered to system spaces containing IT equipment, in order to minimise equipment failures. Temperature-related failures occur both when operating temperatures are too low and when temperatures are too high, with higher temperatures leading to significantly increased failure rates of server hardware. The humidity of the system space also affects equipment failure rates, as electro-static discharges can be generated by electronic equipment if the air is too dry, and corrosion, or conductive anodic filament growth, can occur on electronic equipment where humidity is too high.
System spaces for housing IT equipment are conventionally designed to meet predetermined standards for cooling, such as the ASHRAE (American Society of Heating, Refrigeration and Air-conditioning Engineers) standards, which set out standard-compliant temperature, dew point and humidity ranges and recommended temperature and relative humidity ranges for system spaces housing IT equipment.
The choice of cooling system can have a dramatic effect on the electrical consumption and the total carbon emissions of a system space due to their different electrical demands. It is desirable to use ventilation systems which draw in ambient air for controlling the temperature within system spaces, as ambient-air ventilation requires far less energy than refrigeration-based air-conditioning. Since the ambient temperature is low for much of the time in temperate countries such as in the UK, ventilation systems drawing in ambient air may be capable of delivering air below the maximum allowable standard-compliant temperature for much of the year. It needs to be borne in mind, however, that low temperatures can also be a problem for ambient-air-ventilation systems, as many system spaces should not be maintained at too low a temperature.
In order to minimise operating costs, many lower-grade IT installations, such as those containing cryptocurrency “miners” or “mining rigs”, which typically use lower-performance IT equipment that is tolerant of a wider range of conditions than higher-performance IT equipment, may use very simple fresh-air cooling of system spaces containing their IT equipment. The servers (IT equipment) are typically installed on industrial racking and natural ventilation is used to cool the equipment. In other words, a supply of external air is provided to the system space to cool the IT apparatus. This is only suitable for equipment which can accommodate wide variations in temperature and air which has not been filtered. The servers, or “miners”, used in such systems typically each have an internal fan which provides a positive air flow over the components which require cooling. In most basic installations the air enters the building through open doors. An example of such a system is illustrated at Figure 1, in which servers 2’ are mounted in racks 4’, housed in a system space 6’ such as a building. Ambient fresh air enters the system space through doors 8’ and is exhausted from the system space through roof vents 10’, optionally driven by exhaust fans. Each server comprises a fan for drawing in air to cool that server. The air warmed by passing through each server is returned into the system space.
This sector, using lower-performance IT equipment, is growing in capacity and there is a demand for ever-larger system spaces housing larger volumes/quantities of IT apparatus. For example, larger installations housing IT apparatus cumulatively requiring over 10MW of cooling are now operational. A number of problems must be solved to provide costeffective cooling to such system spaces. One such problem is that when a system space contains a smaller quantity of IT apparatus, as shown in Figure 1, adequate cooling for all of the IT apparatus may be provided simply by allowing air to flow through the doors of the system space. However, if a system space (which might be a building such as a warehouse or industrial unit) contains a larger volume of IT apparatus, then servers (IT apparatus) in the centre of the building cannot draw in cool fresh air because they are positioned in the warm air exhausted by surrounding IT apparatus. Servers in the centre of the system space can therefore be prone to overheating as both the server density within a system space and the cooling requirement of the system space increase.
This is illustrated at Figure 2, which shows a larger system space than Figure 1, cooled in the same way. (The same reference numerals as in Figure 1 have been used.) The servers 2’ near the centre of the system space are surrounded by servers that are venting warmed air 12’ into the system space. The servers near the centre of the system space, at A, therefore cannot draw in air that is sufficiently cool to provide the required cooling effect. These servers may therefore be expected to be unreliable or to fail.
Mechanical fans can be provided at the air inlets and/or the air exhausts to and from the system space. This can increase airflow and improve cooling but, in the case of very large installations, this approach still cannot provide adequate cooling.
A more sophisticated approach to providing cooling air to IT apparatus throughout a large system space is to use a “cold aisle”. This is a conventional way to provide cooling to a system space housing high-performance IT apparatus, and involves arranging the system space so that cooling air is provided to a cold aisle of the system space. Air in the cold aisle is then directed to, or drawn by, individual IT apparatus to cool that IT apparatus, before being exhausted, preferably into a “hot aisle” separate from the cold aisle. The use of hot and cold aisles keeps cold input air separate from warm exhaust air, improving the efficiency of cooling. A drawback of this arrangement, however, is that it may require a lot of space, and can therefore be difficult to provide in confined spaces.
Attempts have been made in the past to house racks of IT equipment in temporary structures such as shipping containers. However, the size and shape of conventional shipping containers, and the requirement for continuous cooling of IT equipment, has made this difficult.
Standard shipping containers are approximately 2.4m wide, while standard racking (shelving) typically used to support banks of IT equipment is 1.2m wide. The long and narrow shape of such containers therefore means that it is difficult to fit an acceptable number of racks, while leaving sufficient space for users to access the IT equipment from both sides for maintenance.
The shape of the containers also means that airflow through the container is often compromised. Where ventilation is provided by opening doors on an end of the container, for example, the IT equipment closest to the doors may receive the coldest air, while the racks further away from the open doors receive hotter air exhausted from the intervening racks. The shape and size of the containers also mean that space is restricted, and the arrangement of the container into hot and cold aisles is difficult and space-inefficient.
All of these issues mean that prior attempts to provide banks of IT equipment, or data centres, inside shipping containers, have been space-inefficient, poorly cooled, and unable to achieve the desired high power density.
Summary of the Invention
The invention provides a modular skirt for an IT device, a support structure for supporting one or more IT devices, a housing for containing IT equipment, and a ventilation system for providing a stream of controlled-temperature air, as defined in the appended independent claims, to which reference should now be made. Preferred or advantageous features of the invention are set out in dependent subclaims.
In a first aspect, the invention may provide a modular skirt for an IT device, in which the skirt is configured to surround a portion of the IT device and to extend radially outwardly from the IT device.
The modular skirt of the present invention may advantageously allow an IT device to be supported on its end on a support structure, such as a rack or shelf.
IT devices such as computer servers, graphic processing units (GPUs), application specific integrated circuits (ASICs), and cryptocurrency miners such as bitcoin miners, typically comprise output fans arranged to eject exhaust air that has been heated as it flows through the IT device to provide cooling. In order to keep these exhaust fans unobstructed, IT devices are typically supported on racks in a “horizontal” orientation, so that the outlet fan is on a vertical end-wall of the device. In this arrangement the outlet fan exhausts air in a horizontal direction.
The modular skirt may advantageously allow an IT device to be supported on its end, so that the rotational axis of its exhaust fan, and/or its inlet fan (which is typically on the opposite wall from the exhaust fan) is arranged vertically. In this configuration, air would be drawn in and exhausted in a vertical direction. In the past, this arrangement has been avoided, as it would be undesirable for either the inlet fan or the exhaust fan to be blocked by the rack on which the IT device sits.
The modular skirt may be configured to surround a portion of the IT device between an inlet fan and an exhaust fan of the IT device, or between an air inlet and an air outlet of the IT device.
Preferably the modular skirt is additionally configured to extend beyond an end of the IT device. This may advantageously allow the skirt to support the IT device on its end, while elevating the end of the IT device above the level of a surface on which it sits. This may improve air flow out of the exhaust fan, or into the input fan.
Preferably the skirt is configured to sit on a surface, and to support the IT device above the surface, or within an opening in the surface. This may advantageously allow the IT device to be supported upright (with the rotational axis of its input and/or exhaust fan vertical, or upright) on the surface.
Supporting IT devices in an upright arrangement, so that exhaust fans are arranged to exhaust hot air vertically, may allow for an improved density of IT devices in a system space. In addition, this arrangement may be adapted to effectively create hot and cold aisles above and below the IT equipment in a way that may be more space-efficient than conventional horizontal racking.
The skirt may be configured to abut, or mate with, one or more other modular skirts, such that the outwardly projecting portions of the skirts are connectable to form a continuous skirt, each skirt preferably being continuous. Each skirt preferably contains no openings when the skirt is positioned around an IT device. Thus, a plurality of IT devices may be arranged in close proximity, so that their skirts form a continuous layer. This continuous layer may advantageously separate hot and cold aisles in the system space.
Particularly preferably the skirts may form an effective roof, or floor, of a plenum chamber or passageway for air handling.
The modular nature of the skirts may advantageously allow flexibility in the number of IT devices housed in the system space.
Preferably the skirt is configured to fit around a server, or a graphic processing unit (GPU), or a cryptocurrency miner, or an application specific integrated circuit (ASIC) device.
According to a second aspect of the invention there is provided a support structure for supporting one or more IT devices, in which the support structure is configured to support the IT device so that a fan of the IT device is directed vertically, preferably vertically downwards.
An inlet fan or an exhaust fan of the IT device may be directed vertically downwards. That is, the rotational axis of the fan may be directed in a vertical direction, and the fan may be configured to direct air downwards.
Preferably the support structure comprises a foraminous, or perforated, surface configured to support a plurality of IT devices. The foraminous surface may be formed from mesh material, for example a metallic mesh material. The holes in the foraminous surface are preferably sufficiently large and/or sufficiently dense, to allow air to flow freely through the surface.
The foraminous surface may be arranged to form a flat, horizontal surface.
Preferably the support structure may be configured such that the foraminous surface forms an upper surface, or roof, of the support structure.
The support structure is preferably configured to support a plurality of servers, or GPUs, or cryptocurrency miners, or ASICs.
The support structure may comprise one or more walls configured to form a chamber, or passage, below the foraminous surface. The one or more walls are preferably solid, nonperforated walls. Air may flow into the chamber, or passage, through the foraminous surface of the support structure.
The chamber, or passage, may have one or more outlets through which air may flow out of the passage.
According to a preferred embodiment, the support structure is configured to support one or more modular skirts according to the first aspect of the invention, or to support a plurality of GPUs or cryptocurrency miners or ASICs supported by modular skirts according to the first aspect of the invention.
When IT devices with modular skirts are supported on the support structure, the inlet or outlet fans of the IT devices will be arranged to face the foraminous surface of the support structure.
When the exhaust fans are arranged to face the foraminous surface, the exhaust fans may cause exhaust air to flow out of the IT devices, through the foraminous surface of the support structure, and into the passage.
Alternatively, when the inlet fans of the IT devices are arranged to face the foraminous surface, the inlet fan may cause air to flow out of the passage, through the foraminous surface of the support structure, and into the IT device. Hot air may then be exhausted vertically above the IT devices.
In this arrangement, the modular skirts of the IT devices advantageously form an effective roof of the passage, so that air can only flow from the passage to the space above the skirts, and vice versa, through the IT devices. This may effectively create a cold aisle on one side of the skirts and a hot aisle on the other side.
The support structure and the modular skirts may advantageously allow the IT devices to be individually removed from the support structure for maintenance, simply by lifting an IT device off the support structure. This may overcome the previous need for user access to both sides of IT devices housed on horizontal racks.
According to a third aspect of the invention there is provided a housing for containing IT equipment, in use, the housing comprising one or more support structures according to the second aspect of the invention.
As described in the background section above, attempts which have been made to house racks of IT equipment in temporary structures such as shipping containers have faced problems due to the long and narrow shape of such containers. This shape can mean that airflow is compromised, and that the layout does not allow space for an acceptable number of racks as well as space for users to access the IT equipment for maintenance.
This problem may also occur in other prefabricated structures, for example portable buildings or “portacabins”, the dimensions of which may be impractical for housing standard IT racking.
Preferably the housing may be a temporary structure, or a prefabricated building, or a prefabricated shelter.
Preferably the housing may be a modular structure. The housing may be a modular structure that is available in units of standard dimensions, which may be combinable in a modular fashion to increase the size of the overall structure.
The housing may, for example, be a portable cabin, or a prefabricated cabin, of the type typically used as temporary shelters on construction sites. Such cabins are typically provided as long, narrow, modular units, the dimensions of which may suffer the drawbacks described above if racks of IT equipment were installed inside.
In a particularly preferred embodiment, the housing may comprise a shipping container, for example a shipping container of standard ISO dimensions.
The housing preferably has a width of less than 4 m, or less than 3 m, preferably about 2.4 m. In a particularly preferred embodiment of a 20-foot shipping container, the housing has an internal width of about 2.35 m.
The housing preferably has a height of less than 3.5 m, or less than 3 m, preferably less than or equal to about 2.5 m, or about 2.4 m. In a particularly preferred embodiment of a 20-foot shipping container, the housing has an internal height of about 2.38 m.
The housing preferably has an internal volume of less than 100 m3, preferably less than or equal to about 67.5 m3, or less than or equal to about 40 m3, or less than or equal to about 35 m3. In a particularly preferred embodiment of a 20-foot shipping container, the housing has an internal volume of about 33.1 m3.
According to a fourth aspect of the invention there is provided a ventilation system for providing a stream of controlled-temperature air, comprising;
an air-mixing chamber;
a first air inlet arranged to provide a first stream of air to the air-mixing chamber;
a system space for housing IT equipment, in use;
a fan arranged to draw a flow of air from the air-mixing chamber into the system space;
a support structure for supporting one or more IT devices, arranged in the system space;
a passageway, comprising an air inlet formed by the support structure; and a variable-resistance element arranged between the passageway and the air-mixing chamber, so that a flow of air may be drawn from the system space, through the passageway, into the air-mixing chamber;
in which the support structure is configured so that air exhausted from IT equipment supported on the support structure flows into the passageway.
The variable-resistance element may be an adjustable damper.
Preferably the first air inlet is arranged to draw ambient air into the air-mixing chamber.
The container may comprise one or more air filters arranged across the first air inlet, so that air flowing through the first air inlet must flow through the air filter.
The system may additionally comprise a second variable-resistance element arranged across an outlet from the passageway to an exterior of the system space. The outlet may be arranged so that air can flow from the passageway, through the outlet, to the ambient environment outside the system.
Preferably the passageway is arranged in a lower portion of the system space, for example on a floor of the system space. The air inlet to the passageway may advantageously be positioned below the height at which the flow of air from the air-mixing chamber is introduced into the system space.
Particularly preferably, the passageway, and the air inlet formed by the support structure, may be configured so that air in the system space may be drawn through IT devices on the support structures and exhausted downwards into the passageway. The passageway may be configured so that, in use, the passageway is arranged underneath the one or more IT devices supported on the support structure. Thus, IT devices may be arranged in a “vertical-flow” orientation, in which cool air delivered to the system space above the IT devices is drawn downwards through the IT devices and exhausted downwards into the passageway as hot air. The inventor of the present application has found that such an arrangement may be particularly efficient for cooling one or more IT devices.
The ventilation system may comprise at least two support structures arranged in parallel in the system space. The at least two support structures may inlet air to at least two passageways. Multiple support structures, and multiple passageways, may be provided in a modular fashion to vary the number and arrangement of IT devices in the system space.
Preferably the support structures are separated by an aisle, or walkway. This may advantageously allow a user access to the IT equipment for maintenance.
The support structure of the ventilation system may be a support structure according to the second aspect of the invention.
The ventilation system may comprise one or more IT devices supported on the support structure. Preferably the IT devices are configured to exhaust hot air, in use, into the passageway.
The one or more IT devices may comprise one or more servers, graphic processing units (GPUs), cryptocurrency miners such as bitcoin miners, or application specific integrated circuits (ASICs).
The air-mixing chamber, the system space, and the passageway may preferably be provided inside a housing.
Preferably the housing may have a width of less than 4m, or less than 3m, preferably about 2.43m.
Preferably the housing may be a temporary structure, or a prefabricated building, or a prefabricated shelter.
Preferably the housing may be a modular structure. That is, the housing may be available in units of standard dimensions, which may be combinable in a modular fashion to increase the size of the overall structure. Modular housings may advantageously allow easy scalingup of data centres with increasing demands for more computing capacity.
Particularly advantageously, the present invention may provide modular housings with individual ventilation systems. This may allow computing capacity to be scaled-up by adding more modular housing units, while simultaneously providing the required additional cooling capacity for the new IT equipment.
The housing may, for example, be a portable cabin, or a prefabricated cabin, of the type typically used as temporary shelters on construction sites. Such cabins are typically provided as long, narrow, modular units, the dimensions of which may suffer the drawbacks described above if racks of IT equipment were installed inside.
In a particularly preferred embodiment, the housing may comprise a shipping container, for example a shipping container of standard ISO dimensions.
The use of a passageway having an air inlet formed by the support structure may advantageously be a space-efficient and practical arrangement to provide ventilation to IT equipment in a prefabricated or modular housing. Where the housing is a modular or prefabricated unit, it may be time consuming and expensive to modify such a housing with the venting and external cooler units used by the majority of prior art cooling systems. The ventilation system according to the present invention may advantageously require very little or no structural modification to the housing itself, as instead of conventional venting the air may flow through a passageway formed by the support structure itself. The system of the present invention may thus be quick and straightforward to install into a prefabricated or modular housing. As it may advantageously not be necessary to modify the external surface of the housing, a plurality of housings may advantageously be provided adjacent to one another in a modular fashion, if desired.
The ventilation system is preferably configured to be operable in a ventilation mode, or “fresh air” mode. In ventilation mode, the variable-resistance element may be closed, so that no air is drawn through the variable-resistance element. The fan will therefore draw air from only the first air stream of air, so that only ambient air is provided to the system space.
The ventilation system is preferably configured to be operable in an attemperation mode, or “air-mixing” mode. In attemperation mode, the variable-resistance element may be partially closed, or partially open, so that some heated air is drawn through the variable-resistance element, and some air is drawn through the first air inlet, to be mixed in the air-mixing chamber before flowing to the system space. The relative proportions of air drawn in each stream may be controlled by controlling the position of the variable-resistance element. Attemperation mode may advantageously be usable in sufficiently cold or mild weather conditions where the ambient air is not standard-compliant for the system space.
The ventilation system may optionally comprise an additional air-cooling system, or may be a “pure” ventilation system with no additional air-cooling system.
The direction of air flow through the ventilation system may be reversed by swapping the positions of the fan and the variable-resistance element. For example, cool air from the air mixing chamber may be delivered to the passageway instead of the system space, and then drawn upwards through the IT equipment to be exhausted into the system space. In such an arrangement, the variable-resistance element should be arranged between the system space and the air-mixing chamber, and the system space may have an outlet, optionally spanned by a second variable-resistance element, through which air may flow to an exterior of the system.
There may be provided a ventilation system for IT equipment, comprising;
an air-mixing chamber;
a first air inlet arranged to provide a first stream of air to the air-mixing chamber;
a system space for housing IT equipment, in use;
a support structure for supporting one or more IT devices, arranged in the system space;
a passageway, comprising an air outlet formed by the support structure;
a fan arranged to draw a flow of air from the air-mixing chamber into the passageway; and a variable-resistance element arranged between the system space and the airmixing chamber, so that a flow of air may be drawn from the air-mixing chamber, through the passageway, into the system space;
in which the support structure is configured so that air exhausted from IT equipment supported on the support structure flows into the system space.
Other features of this arrangement may be as described above.
According to a fifth aspect of the invention there is provided a shipping container configured to house IT equipment, comprising:
an air-mixing chamber arranged inside the container;
a first air inlet arranged to provide a first stream of air to the air-mixing chamber;
a system space inside the container;
a fan arranged to draw a flow of air from the air-mixing chamber into the system space;
a support structure for supporting one or more IT devices, arranged in the system space;
a passageway, comprising an air inlet formed by the support structure; and a variable-resistance element arranged between the passageway and the air-mixing chamber, so that a flow of air may be drawn from the system space, through the passageway, into the air-mixing chamber;
in which the support structure is configured so that air exhausted from IT equipment supported on the support structure flows into the passageway.
The shipping container is preferably a metal shipping container of standard dimensions.
The shipping container may be of standard ISO dimensions. For example, the shipping container may have external dimensions of 2.43m (8 ft) wide, 2.59m (8.5m) high and 6.06m (20ft) long (a 20 foot container). A standard ISO 20 foot container has a capacity of 1,169 ft3. Alternatively, the shipping container may have external dimensions of 2.43m (8 ft) wide, 2.59m (8.5m) high and 12.2m (40ft) long (a 40 foot container). A standard ISO 40 foot container has a capacity of 2,385 ft3.
Preferably the first air inlet is arranged to draw ambient air into the air-mixing chamber.
The first air inlet may advantageously comprise, or span, at least a portion of the doorway of the shipping container. Standard shipping containers comprise doors spanning one or both ends of the container. Shipping container doors are advantageously arranged to span the entire width and height of the container. Thus, by arranging the first air inlet to span the doorway of the shipping container, fresh air may be drawn through the first air inlet by opening or removing the doors of the container. When cooling is not required, for example when no IT equipment is in use in the container, the doors may be closable to secure the IT equipment and protect the inside of the container from the weather.
An access door, through which a user may enter the system space, may be provided in an end of the container opposite the first air inlet.
Preferably the container comprises a droplet separator over the first air inlet, to prevent snow, rain or mist from entering the air-mixing chamber through the first air inlet.
The container may comprise an air filter arranged across the first air inlet, so that air flowing through the first air inlet must flow through the air filter.
The container may additionally comprise a second variable-resistance element arranged across an outlet from the passageway to the exterior of the container.
The passageway may be arranged on the base of the container. This may advantageously facilitate a “vertical flow” arrangement through the IT devices, as discussed above.
The shipping container may comprise two or more support structures arranged lengthways along the container, preferably along the edges of the container. In a preferred embodiment, the shipping container comprises two support structures arranged lengthways along the container.
The support structures are preferably separated by a central aisle or walkway. This may advantageously allow a user to easily access the IT equipment for maintenance.
In a preferred embodiment, the support structure is a support structure according to the second aspect of the invention.
Preferably the shipping container comprises one or more IT devices supported on the support structure(s). The IT devices may be configured to exhaust hot air, in use, into the passageway.
The system may be modified to reverse the direction of the air flow in the system. For example, by positioning the fan to draw air into the passage, and positioning the variableresistance element to control air flow from the system space to the air-mixing chamber, it would be possible for cold air to be provided through the passage below the IT equipment, and exhausted from the system space.
The one or more IT devices may preferably comprise one or more GPUs, or cryptocurrency miners, or ASICs.
The shipping container is preferably configured to be operable in a ventilation mode, or “fresh air” mode. In ventilation mode, the variable-resistance element may be closed, so that no air is drawn through the variable-resistance element. The fan will therefore draw air from only the first air stream of air, so that only ambient air is provided to the system space.
The shipping container is preferably configured to be operable in an attemperation mode, or “air-mixing” mode. In attemperation mode, the variable-resistance element may be partially closed, or partially open, so that some heated air is drawn through the variableresistance element, and some air is drawn through the first air inlet, to be mixed in the airmixing chamber before flowing to the system space. The relative proportions of air drawn in each stream may be controlled by controlling the position of the variable-resistance element. Attemperation mode may advantageously be usable in sufficiently cold or mild weather conditions where the ambient air is not standard-compliant for the system space.
The container may optionally comprise an additional air-cooling system.
Features described in relation to one aspect of the invention may be equally applicable to other aspects of the invention.
Brief Description of the Drawings
Specific embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figures 1 and 2 are schematic diagrams of first and second prior art system spaces;
Figure 3 is a schematic cross-section taken lengthways through a shipping container according to a preferred embodiment of the present invention;
Figure 4 is a schematic perspective view of a shipping container containing a plurality of ASIC bitcoin miners, according to a preferred embodiment of the present invention;
Figure 5 is a schematic perspective view of a shipping container containing a plurality of graphic processing units (GPUs), according to a preferred embodiment of the present invention;
Figure 6 is a schematic cross-section of the shipping container of Figure 3, operating in a ventilation mode;
Figure 7 is a schematic cross-section of the shipping container of Figure 3, operating in an attemperation mode;
Figure 8 is a schematic cross-section of the shipping container of Figure 3, operating in a recirculation mode;
Figure 9 is a schematic plan view of the shipping container of Figure 4;
Figure 10 is a schematic plan view of the shipping container of Figure 5;
Figure 11 is a schematic side view of three IT devices attached to modular skirts according to a preferred embodiment of the present invention;
Figure 12 is a schematic cross-section taken lengthways through a shipping container according to a preferred embodiment of the present invention.
In the description above, the prior art systems illustrated in Figures 1 and 2 have been discussed.
Figure 3 illustrates a first preferred embodiment of the invention, which has the following elements:
- Inlet air
- Water droplet separator
- Hot/cold air-mixing chamber
- Supply fan
- Warm air supply chamber (system space)
- Down-flow computer equipment
- Outlet
- Hot air to outlet
- Hot air to recirculation and mixing
11- Flow control dampers
- Air filter
- Support structure
- Passage
- Perforated surface of support structure
The diagram shows the ventilation system of the present invention employed for the cooling of computer equipment in a modified shipping container, according to a preferred embodiment of the present invention.
An air filter 12 is arranged across air inlets formed in an end of the shipping container, so that ambient air may be drawn into the container for ventilation through the air filter. The system comprises a droplet separator 2 to protect the air filter 12 from snow, rain or mist.
A supply fan 4 creates a negative pressure difference in the mixing chamber, which draws ambient air 1 into the air-mixing chamber 3. Air from the air-mixing chamber is supplied to a system space 5 housing computer equipment 6 by a supply fan 4.
The computer equipment, or IT equipment, 6 is supported on support structures 20, so that the IT equipment is arranged upright, with its exhaust fans facing downwards towards the support structures.
The computer equipment 6 is installed in a down-flow configuration. In this configuration, the fan 4 supplies cool air to the system space 5 at a desired temperature for delivery to the IT equipment 6. The inlet and outlet fans (not shown) integrated into the IT equipment draws the air downwards through the IT equipment and exhausts warmed air out of the bottom of the IT equipment, through a perforated upper surface 50 of the support structure, into a passage 25 below the IT equipment. This passage forms a hot aisle.
From the passage 25, heated air 10 may be recirculated to the air-mixing chamber 3, through the flow control damper (variable-resistance element) 11 for mixing with ambient air from outside the container. The position of the flow control damper 11 is variable to alter the flow of hot recirculated air 10 from the passage 25 into the air-mixing chamber.
Heated air 9 may also flow out of the outlet 7 to be exhausted outside the container.
The purpose of the apparatus is to provide filtered air at a controllable temperature to the shipping container, and so cool heat-generating IT equipment.
Figure 12 shows an alternative embodiment of the ventilation system of the present invention. The ventilation system of Figure 12 is identical to the system of Figure 3, with the addition of a variable-resistance outlet damper 120 positioned across outlet 7. The position of the outlet damper 120 is variable to alter the flow of hot air 9 from the passage 25 out of the outlet 7.
As shown in Figures 4 and 5, the container comprises two support structures 20 forming two passages on the container floor along opposite walls. An aisle is arranged along the centre of the container between the passages, to allow user access.
Figure 4 shows the shipping container containing a plurality of ASICs 200 supported on the perforated surfaces 50 of the support structures 20, while Figure 5 shows the shipping container containing a plurality of graphic processing units (GPUs) 300 supported on the perforated surfaces 50 of the support structures 20.
Figure 6 shows the shipping container operating in a ventilation mode, or “fresh air” mode. In ventilation mode, the variable-resistance element 11 is closed, so that no air is drawn from the passage, through the variable-resistance element, into the air-mixing chamber. The fan will therefore draw only ambient air from the first air inlet, so that only ambient air is provided to the system space. The air is drawn through the IT equipment to cool the IT equipment, and flows into the passage before being exhausted through the exhaust 7.
Figure 7 shows the shipping container operating in an attemperation mode, or “air-mixing” mode. In attemperation mode, the variable-resistance element is partially closed, so that some heated air is drawn through the variable-resistance element 11 into the air-mixing chamber, and some air is drawn through the first air inlet, to be mixed in the air-mixing chamber before flowing to the system space. The relative proportions of air drawn in each stream are controllable by controlling the position of the variable-resistance element.
Figure 8 shows the shipping container operating in full recirculation mode. In this mode, the variable-resistance element 11 is fully open, providing a low-resistance pathway for heated air to flow from the passage into the air-mixing chamber 3. As the resistance of the open damper is less than that of the air filter 12, the fan 4 will draw recirculated air from the passage, through the air mixing chamber, and back into the system space for delivery to the IT equipment.
Figures 9 and 10 show plan views of two possible embodiments of the shipping container. The support structures in the shipping container may advantageously support a variety of types of IT equipment. In two particularly preferred embodiments, the container may contain a plurality of application-specific integrated circuits (ASICs) 200 mounted on the support structures, or a plurality of graphic processing units (GPUs) 300 mounted on the support structures. ASICs and GPUs both require a lot of cooling power.
The upright, down-flow configuration of the ventilation system is particularly suitable for ASICs and GPUs, as due to their size and shape this configuration, which is not possible with conventional computing racks, provides a higher power density than other arrangements.
The down-flow configuration allows greater numbers of computer equipment to be installed compared to conventional installations such as computer racks. This configuration also creates an effective cold aisle in the system space 5 above the IT devices, and an effective hot aisle in the passage 25 below the IT devices.
This layout also allows simple changes between different computer equipment of varying sizes and air flow rates.
Figure 11 shows a cross section of three ASICs 200, each arranged in a modular skirt 100 according to a preferred embodiment of the invention. The skirts each surround an ASIC, and extend radially outwards from the central axis of the ASIC. The skirts are shaped so that they project below the bottom of the ASICs, so that when they are arranged on the perforated surface 50 of a support structure, the ASIC is raised off the perforated surface. This prevents the exhaust fans of the ASICs from being obstructed by the perforated surface.
The edges of the modular skirts are advantageously shaped to abut one another, and to link together to form a continuous layer of skirt. This may advantageously prevent air flow through the perforated surface except through the ASICs themselves.
While illustrated with ASICs, the modular skirts may instead be shaped to surround other items of IT equipment.
Claims (25)
1. A modular skirt for an IT device, in which the skirt is configured to surround a portion of the IT device and to extend radially outwardly from the IT device.
2. A modular skirt according to claim 1, in which the skirt is additionally configured to extend beyond an end of the IT device.
3. A modular skirt according to claim 2, in which the skirt is configured to sit on a surface, and to support the IT device above the surface, or within an opening in the surface.
4. A modular skirt according to claim 1, 2 or 3, in which the skirt is configured to abut, or mate with one or more other modular skirts, such that the outwardly projecting portions of the skirts are connectable to form a continuous skirt, each skirt preferably being continuous, and containing no openings.
5. A modular skirt according to any of claims 1 to 4, in which the skirt is configured to fit around a graphic processing unit (GPU), or a cryptocurrency miner, or an application specific integrated circuit (ASIC) device.
6. A support structure for supporting one or more IT devices, in which the support structure is configured to support the IT device so that a fan of the IT device is directed vertically upwards or downwards.
7. A support structure according to claim 6, in which the support structure comprises a foraminous surface configured to support a plurality of IT devices.
8. A support structure according to claim 6 or 7, in which the support structure is configured to support a plurality of graphic processing units (GPUs), or cryptocurrency miners, or application specific integrated circuits (ASICs).
9. A support structure according to claim 7 or 8, comprising one or more walls configured to form a chamber, or passage, below the foraminous surface.
10. A support structure according to any of claims 6 to 9, configured to support one or more modular skirts according to any of claims 1 to 5, or to support a plurality of IT devices supported by modular skirts according to any of claims 1 to 5.
11. A housing for containing IT equipment, the housing comprising one or more support structures according to any of claims 6 to 10.
12. A housing according to claim 11, in which the housing has a width of less than 4m, or less than 3 m, preferably about 2.43 m.
13. A housing according to claim 11 or 12, in which the housing comprises a shipping container, or a portable cabin, or a prefabricated cabin.
14. A ventilation system for providing a stream of controlled-temperature air, comprising;
an air-mixing chamber;
a first air inlet arranged to provide a first stream of air to the air-mixing chamber;
a system space for housing IT equipment, in use;
a fan arranged to draw a flow of air from the air-mixing chamber into the system space;
a support structure for supporting one or more IT devices, arranged in the system space;
a passageway, comprising an air inlet formed by the support structure; and a variable-resistance element arranged between the passageway and the air-mixing chamber, so that a flow of air may be drawn from the system space, through the passageway, into the air-mixing chamber;
in which the support structure is configured so that air exhausted from IT equipment supported on the support structure flows into the passageway.
15. A ventilation system according to claim 14, additionally comprising a second variable-resistance element arranged across an outlet from the passageway to an exterior of the system space.
16. A ventilation system according to claim 14 or 15, in which the passageway is arranged on a floor of the system space.
17. A ventilation system according to claim 14, 15 or 16, comprising at least two support structures arranged in parallel in the system space.
18. A ventilation system according to claim 17, in which the support structures are separated by an aisle, or walkway.
19. A ventilation system according to any of claims 14 to 19, in which the support structure is a support structure according to any of claims 5 to 10.
20. A ventilation system according to any of claims 14 to 19, comprising one or more IT devices supported on the support structure, in which the IT devices are configured to exhaust hot air, in use, into the passageway.
21. A ventilation system according to claim 20, in which the one or more IT devices comprise one or more GPUs, or cryptocurrency miners, or ASICs.
22. A ventilation system according to any of claims 14 to 21, in which the passageway is arranged in a lower portion of the system space so that, in use, air exhausted from IT equipment supported on the support structure flows downwards into the passageway.
23. A ventilation system according to any of claims 14 to 22, in which the air-mixing chamber, the system space, and the passageway are provided inside a housing.
24. A ventilation system according to claim 23, in which the housing has a width of less than 4m, or less than 3m, preferably about 2.43m.
25. A ventilation system according to claim 23 or 24, in which the housing comprises a shipping container, or a portable cabin, or a prefabricated cabin.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1806196.0A GB2575619A (en) | 2017-12-08 | 2018-04-16 | Modular skirt, support structure, housing for IT equipment, and ventilation system |
| GB1813888.3A GB2569839A (en) | 2017-12-08 | 2018-08-24 | Mounting apparatus for an IT device |
| PCT/GB2018/053568 WO2019111021A1 (en) | 2017-12-08 | 2018-12-07 | Ventilation system and support system for it devices |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1720547.7A GB2569181A (en) | 2017-12-08 | 2017-12-08 | Modular skirt, support structure, and container for IT equipment |
| GB1806196.0A GB2575619A (en) | 2017-12-08 | 2018-04-16 | Modular skirt, support structure, housing for IT equipment, and ventilation system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB201806196D0 GB201806196D0 (en) | 2018-05-30 |
| GB2575619A true GB2575619A (en) | 2020-01-22 |
Family
ID=61007281
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1720547.7A Withdrawn GB2569181A (en) | 2017-12-08 | 2017-12-08 | Modular skirt, support structure, and container for IT equipment |
| GB1806196.0A Withdrawn GB2575619A (en) | 2017-12-08 | 2018-04-16 | Modular skirt, support structure, housing for IT equipment, and ventilation system |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB1720547.7A Withdrawn GB2569181A (en) | 2017-12-08 | 2017-12-08 | Modular skirt, support structure, and container for IT equipment |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB2569181A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2025245644A1 (en) * | 2024-05-30 | 2025-12-04 | Upstream Data Inc. | Portable blockchain mining devices with internal recirculation systems, and methods of use |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5672102A (en) * | 1996-08-21 | 1997-09-30 | Toshiba America Information Systems, Inc. | Dust reduction system for electronic enclosures |
| US20090122484A1 (en) * | 2007-11-09 | 2009-05-14 | Panduit Corp. | Cooling System |
| US20110260591A1 (en) * | 2010-04-21 | 2011-10-27 | Hon Hai Precision Industry Co., Ltd. | Server assembly with multi-funtional fixing frame |
| US20120013092A1 (en) * | 2010-07-19 | 2012-01-19 | Hon Hai Precision Industry Co., Ltd. | Rack for electronic apparatus |
| WO2015109748A1 (en) * | 2014-01-23 | 2015-07-30 | 华为技术有限公司 | Air directing system |
| US20160249479A1 (en) * | 2015-02-19 | 2016-08-25 | Fujitsu Limited | Electronic device and method for mounting unit |
| US20160270253A1 (en) * | 2015-03-09 | 2016-09-15 | Adtran, Inc. | Convection-cooled electronic system |
-
2017
- 2017-12-08 GB GB1720547.7A patent/GB2569181A/en not_active Withdrawn
-
2018
- 2018-04-16 GB GB1806196.0A patent/GB2575619A/en not_active Withdrawn
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5672102A (en) * | 1996-08-21 | 1997-09-30 | Toshiba America Information Systems, Inc. | Dust reduction system for electronic enclosures |
| US20090122484A1 (en) * | 2007-11-09 | 2009-05-14 | Panduit Corp. | Cooling System |
| US20110260591A1 (en) * | 2010-04-21 | 2011-10-27 | Hon Hai Precision Industry Co., Ltd. | Server assembly with multi-funtional fixing frame |
| US20120013092A1 (en) * | 2010-07-19 | 2012-01-19 | Hon Hai Precision Industry Co., Ltd. | Rack for electronic apparatus |
| WO2015109748A1 (en) * | 2014-01-23 | 2015-07-30 | 华为技术有限公司 | Air directing system |
| US20160249479A1 (en) * | 2015-02-19 | 2016-08-25 | Fujitsu Limited | Electronic device and method for mounting unit |
| US20160270253A1 (en) * | 2015-03-09 | 2016-09-15 | Adtran, Inc. | Convection-cooled electronic system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB201806196D0 (en) | 2018-05-30 |
| GB201720547D0 (en) | 2018-01-24 |
| GB2569181A (en) | 2019-06-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7259963B2 (en) | Rack height cooling | |
| US9888614B1 (en) | Modular data center row infrastructure | |
| JP5209584B2 (en) | Modular data center | |
| AU2016273127B2 (en) | Data centre cooling system | |
| US8659895B1 (en) | Air-cooled data center rows | |
| EP2852268B1 (en) | Container-type data center cluster | |
| US7529086B2 (en) | Data center cooling | |
| EP2156268B1 (en) | Cold row encapsulation for server farm cooling system | |
| US9674988B2 (en) | Method and device for reducing the energy consumption of a center comprising energy-intensive apparatuses | |
| US20100216388A1 (en) | Systems and Methods for Closed Loop Heat Containment with Cold Aisle Isolation for Data Center Cooling | |
| US20100248609A1 (en) | Assembly For Providing A Downflow Return Air Supply | |
| EP2531673A1 (en) | Modular datacenter element and modular datacenter cooling element | |
| US10986753B2 (en) | Water-assisted air cooling for a row of cabinet | |
| US10939588B2 (en) | Airflow distribution and management architecture for large data center | |
| US20110209852A1 (en) | Method and system for cooling apparatus racks | |
| GB2569839A (en) | Mounting apparatus for an IT device | |
| GB2575619A (en) | Modular skirt, support structure, housing for IT equipment, and ventilation system | |
| US20090029640A1 (en) | Air Scavenging System for Removing Heated Conditioned Air from a Computer Room | |
| ES2509219T3 (en) | Procedure and device to reduce the energy consumption of a center consisting of equipment that consumes a lot of energy | |
| KR102856295B1 (en) | Air circulation system and air circulation method using natural convection | |
| HK1107742B (en) | Data center cooling | |
| HK1142478A (en) | Data center cooling |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AT | Applications terminated before publication under section 16(1) | ||
| S20A | Reinstatement of application (sect. 20a/patents act 1977) |
Free format text: REQUEST FOR REINSTATEMENT FILED Effective date: 20190308 |
|
| S20A | Reinstatement of application (sect. 20a/patents act 1977) |
Free format text: REQUEST FOR REINSTATEMENT ALLOWED Effective date: 20190319 |
|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |