News Column

Patent Issued for Cold Row Encapsulation for Server Farm Cooling System

July 2, 2014

By a News Reporter-Staff News Editor at Journal of Engineering -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Noteboom, Scott (San Jose, CA); Robison, Albert Dell (Placerville, CA), filed on September 26, 2011, was published online on June 17, 2014.

The patent's assignee for patent number 8755182 is Yahoo! Inc. (Sunnyvale, CA).

News editors obtained the following quote from the background information supplied by the inventors: "The rapid growth of Internet services such as Web email, Web search, Web site hosting, and Web video sharing is creating increasingly high demand for computing and storage power from servers in data centers. While the performance of servers is improving, the power consumption of servers is also rising despite efforts in low power design of integrated circuits. For example, one of the most widely used server processors, AMD's Opteron processor, runs at up to 95 watts. Intel's Xeon server processor runs at between 110 and 165 watts. Processors are only part of a server, however; other parts in a server such as storage devices consume additional power.

"Servers are typically placed in racks in a data center. There are a variety of physical configurations for racks. A typical rack configuration includes mounting rails to which multiple units of equipment, such as server blades, are mounted and stacked vertically within the rack. One of the most widely used 19-inch rack is a standardized system for mounting equipment such as 1 U or 2 U servers. One rack unit on this type of rack typically is 1.75 inches high and 19 inches wide. A rack-mounted unit (RMU) server that can be installed in one rack unit is commonly designated as a 1 U server. In data centers, a standard rack is usually densely populated with servers, storage devices, switches, and/or telecommunications equipment. In some data centers, fanless RMU servers are used to increase density and to reduce noise.

"A data center room should be maintained at acceptable temperatures and humidity for reliable operation of the servers, especially for fanless servers. The power consumption of a rack densely stacked with servers powered by Opteron or Xeon processors may be between 7,000 and 15,000 watts. As a result, server racks can produce very concentrated heat loads. The heat dissipated by the servers in the racks is exhausted to the data center room. The heat collectively generated by densely populated racks can have an adverse effect on the performance and reliability of the equipment in the racks, since they rely on the surrounding air for cooling. Accordingly, heating, ventilation, air conditioning (HVAC) systems are often an important part of the design of an efficient data center.

"A typical data center consumes 10 to 40 megawatts of power. The majority of energy consumption is divided between the operation of servers and HVAC systems. HVAC systems have been estimated to account for between 25 to 40 per cent of power use in data centers. For a data center that consumes 40 megawatts of power, the HVAC systems may consume 10 to 16 megawatts of power. Significant cost savings can be achieved by utilizing efficient cooling systems and methods that reduce energy use. For example, reducing the power consumption of HVAC systems from 25 percent to 10 percent of power used in data centers translates to a saving of 6 megawatts of power which is enough to power thousands of residential homes.

"In a data center room, server racks are typically laid out in rows with alternating cold and hot aisles between them. All servers are installed into the racks to achieve a front-to-back airflow pattern that draws conditioned air in from the cold rows, located in front of the rack, and ejects heat out through the hot rows behind the racks. A raised floor room design is commonly used to accommodate an underfloor air distribution system, where cooled air is supplied through vents in the raised floor along the cold aisles.

"An important factor in efficient cooling of data center is to manage the air flow and circulation inside a data center. Computer Room Air Conditioners (CRAC) units supply cold air through floor tiles including vents between the racks. In addition to servers, CRAC units consume significant amounts of power as well. One CRAC unit may have up to three 5 horsepower motors and up to 150 CRAC units may be needed to cool a data center. The CRAC units collectively consume significant amounts of power in a data center. For example, in a data center room with hot and cold row configuration, hot air from the hot rows is moved out of the hot row and circulated to the CRAC units. The CRAC units cool the air. Fans powered by the motors of the CRAC units supply the cooled air to an underfloor plenum defined by the raised sub-floor. The pressure created by driving the cooled air into the underfloor plenum drives the cooled air upwardly through vents in the subfloor, supplying it to the cold aisles where the server racks are facing. To achieve a sufficient air flow rate, hundreds of powerful CRAC units may be installed throughout a typical data center room. However, since CRAC units are generally installed at the corners of the data center room, their ability to efficiently increase air flow rate is negatively impacted. The cost of building a raised floor generally is high and the cooling efficiency generally is low due to inefficient air movement inside the data center room. In addition, the location of the floor vents requires careful planning throughout the design and construction of the data center to prevent short circuiting of supply air. Removing tiles to fix hot spots can cause problems throughout the system."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "The present invention provides systems and methods directed to efficient cooling of data centers where fanless rack mounted servers may be installed. In a particular embodiment, the present invention provides a cold row encapsulation structure comprising at least one server rack port configured to interface with one or more server racks and a cooling module connected to the top surface of the cold row encapsulation structure. The server rack ports are configured to engage the server racks such that a front face of a rack-mounted unit installed in the server racks interface with the interior space defined by the cold row encapsulation structure. In some embodiments, server racks ports and server racks are tightly connected by clamps and/or sealing gaskets to reduce air leakage into and out of the cold row encapsulation structure.

"Some embodiments of the invention utilize one or more auxiliary fans to draw cold air from the cold row encapsulation structure through the front face of the rack-mounted units in the server racks and to eject hot air from the back side of the rack-mounted units. In some embodiments, the one or more fans may be enclosed in a fan unit and operably attached to the server racks to draw air from the cold row encapsulation structure to cool servers installed on the server racks. Some embodiments of the invention obviate the need for raised subfloors, and the fans and other equipment for forcing cooled air into an underfloor plenum. In addition, some embodiments obviate the need for rack-mounted units, such as servers, disk arrays, and the like, to include internal fans. In other embodiments, the fans of the cooling system can be used as an auxiliary or supplement to the internal fans of the rack-mounted units. The cooling module installed on top of the cold row encapsulation structure cools the hot air through cooling coils installed inside the cooling module. In some embodiments, cold water is used inside the coils to exchange heat with hot air in the cooling module.

"In one embodiment of the present invention, the systems and methods are directed to cooling hot air inside the data center server cooling room without introducing outside air. The air is cooled by the water based cooling coils inside the cooling modules and the cooled air enters the cold row encapsulation structure through gravity and the lower pressure created inside the interior space of the cold row encapsulation structure. One or more fans draw cold air through the rack-mounted units in the server racks connected to the cold row encapsulation structure to cool the servers and eject hot air from the back side of the server racks. In some embodiments, the fans are enclosed in a fan unit.

"In other embodiments of the present invention, the systems and methods involve mixing outside cool air to cool the servers. In one embodiment, ceiling dampers in a data center may be controlled by a temperature control unit and opened up when the outside temperature reaches certain threshold value. Outside air enters the data center and passes through the cooling module installed on top of the cold row encapsulation structure. One or more fans draw the cold air from the cold row encapsulation structure. Hot air is exhausted to the outside by the ceiling exhaust fans. In some embodiments, to control the moisture in the air in the data center server cooling room, especially when the outside air fails to meet the operating requirements for the servers and other equipment, humidifiers may be used to condition the outside air. In recent years, however, manufacturers of server equipment have significantly relaxed the humidity requirements due to technological advancements.

"The following detailed description together with the accompanying drawings will provide a better understanding of the nature and advantages of various embodiments of the present invention."

For additional information on this patent, see: Noteboom, Scott; Robison, Albert Dell. Cold Row Encapsulation for Server Farm Cooling System. U.S. Patent Number 8755182, filed September 26, 2011, and published online on June 17, 2014. Patent URL:

Keywords for this news article include: Yahoo! Inc.

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Source: Journal of Engineering

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