Patent Application
20110085296
Many datacenters are now populated with computer blades mounted in blade enclosures. A computer blade is defined as a device that accesses power and connections to other blades and devices through a shared infrastructure or enclosure. The computer blade may be rack mounted into the enclosure. A computer blade may also be defined as a device that provides power and connectivity to other blades and devices through the shared infrastructure or enclosure. A computer blade can fulfill a number of different functions. There are blade servers, Input/Output (I/O) blades, memory blades, power supply blades, I/O interconnect blades, and the like. As the computer blades have increased in power density, cooling the blades has become a challenge.
Blades are typically cooled by drawing ambient air through the blade enclosure to remove the heat generated by the components mounted on the blades. This solution requires the ambient air to be conditioned to a specific temperature and humidity. Without conditioning, the components may be subject to insufficient cooling, humidity damage, or contamination. Conditioning the air can use a significant portion of the energy required by the datacenter.
Airflow divider 112 is mounted on, and is perpendicular with, the top surface of PC board 102. Airflow divider runs generally down the length of PC board 102. Airflow divider 112 creates a re-circulating airflow path down one side of blade 100 and up the other side of blade 100. Re-circulating airflow path flows down a first airflow channel 120 on one side of PC board 102. Re-circulating airflow path passes through the channels or gaps in cooling fins 110 (shown by arrow 122). Re-circulating airflow path flows up a second airflow channel 124 on the other side of PC board 102. Re-circulating airflow path flows around the second end of PC board 102 (shown by arrow 126) and back into the first airflow channel 120. Fan 114 is mounted on the top surface of PC board 102 in the first airflow channel 120. When fan 114 is not as wide as the first airflow channel 120, spacer 116 may be used to fill the gap between the edge of fan 114 and the side of PC board 102.
Airflow divider can be fabricated out of sheet metal, plastic, or the like. In one example embodiment of the invention, airflow divider may be a PC board assembly electrically connected to, and perpendicular with, PC board 102.
High power component 104 is mounted on the top side of PC board 102 in the second airflow channel 124 near cooling fins 110. DIMMs 106 are mounted on the top side of PC board 102 in the first airflow channel 120. DIMMs 106 are mounted in a side-by-side relationship, parallel with the first airflow channel 120. Other components may also be mounted on the top side of PC board 102. Fan 114 forces air to flow through the re-circulating airflow path. Air flowing through the first airflow channel 120 flows between DIMMs 106. Heat generated by DIMMs 106 is transferred to the air flowing past DIMMs 106. Fan 114 forces the air from the first airflow channel through the gaps in cooling fins 110. Cooling fins 110 cool the air flowing through the gaps between the cooling fins 110. Cooling fins 110 transfer the heat from the air to heat transfer plate 108. Heat is removed from the heat transfer plate as discussed below.
The air cooled by cooling fins 110 flows into the second airflow channel 124. The cooled air in the second airflow channel passes over high power component 104. Heat generated by the high power component 104 is transferred into the cooled air flowing past high power component 104. In one example embodiment of the invention, high power component is located in the second airflow channel near cooling fins 110 and therefore receives the airflow when the air is near its coolest. Because the air is near its coolest when passing over high power component 104, cooling is maximized for the high power component 104. Fan 114 forces air flowing in the second airflow channel 124 around the second end of PC board 102 (shown by arrow 126) and back into the first airflow channel 120.
In one example embodiment of the invention, high power component 104 may be cooled using heat pipes in addition to the air flowing through the re-circulating airflow pathway. One end (the hot end) of the heat pipes would be positioned on top of the high power component 104, with the other end (the cool end) of the heat pipe coupled to the cooling fins 110, or coupled directly to the heat transfer plate 108. A heat spreader may be attached to the top side of high power component 104 to aid in the transfer of heat from the high power component 104 into the heat pipes. In other example embodiments the heat pipe may be replaced with a loop thermosiphon, bubble pump, or other similar technology that allows heat to be transferred across some distance. In this application, the term heat pipe will be used to represent any one of these technologies.
In one example embodiment of the invention, a blade lid is mounted onto the PC board 102.
In one example embodiment, blade lid 200 may not make an air tight seal against PC board 102, as some leakage between the re-circulating airflow pathway and the outside of the blade may be tolerated. In another example embodiment of the invention, blade lid may make an air tight seal preventing air circulation between the blade and the enclosure. In this embodiment, the air inside the enclosure may have higher variations in temperature, humidity, and particle count.
Blade 100 is typically rack mounted into a blade enclosure. There may be a plurality of blades mounted into the blade enclosure. Blade 100 may be any type of blade, for example a blade server, a memory blade, an input/output (I/O) blade, a fabric blade, a graphics blade, or the like. Blade 100 may also be a power supply mounted into a blade enclosure and configured to supply power to other blades mounted in the blade enclosure. When blade 100 is a power supply, power transformers and the like will be the components mounted in the airflow channels, not the high power component 104 or DIMMs 106.
The back side 342 of blade enclosure 340 has a plurality of liquid cooling channels coupled to a cooling system that removes heat from the back side 342 of blade enclosure 340. The cooled back side 342 of the blade enclosure 340 transfers heat away from the heat transfer plate 108 on blade 100. In other example embodiments, chilled air may be used to cool the back side 342 of blade enclosure 340. In another example embodiment of the invention, the sides of blade enclosure 340 may be cooled, and one or more heat transfer plates 108 mounted onto the sides of PC board 102 would be thermally coupled to the cooled sides of blade enclosure 340.
In one example embodiment of the invention, blade 100 is enclosed using a lid 200 or other individual parts that mount directly to blade 100 (as discussed above). In another example embodiment of the invention, the sides and top surface of blade enclosure 340 may act as the lid to enclose the air channels and create the re-circulating air pathway for blade 100. In this example, blade 100 may provide an end plate to block the end of the re-circulating air pathway. Or a front door (not shown) may be attached to blade enclosure 340 and used to block the end of the re-circulating air pathway.
