Abstract: A computer system and method for measuring air density in a computer chassis. The computer chassis includes a fan, an ambient air temperature sensor, and a heat-generating device with a heat sink, a heat sink temperature sensor, and a controller. The controller controls the fan speed and applies a known amount of thermal energy to the heat sink, then determines the air density from the difference in temperature between the ambient air and the heat sink. The controller may then use the air density determination to adjust the air flow rate through the computer chassis to provide a proper air flow rate for cooling.

Abstract: A system comprising a chassis that includes a plurality of modules and a fan assembly disposed in a distal end of the chassis for drawing air in parallel pathways through the plurality of modules. At least one of the modules is a compute module having a thermal sensor disposed to sense the temperature of air flowing across a processor mounted on a motherboard. The system further comprises a fan controller receiving output from the thermal sensor, wherein the fan controller operates the fan assembly to cool the plurality of modules and maintain the thermal sensor output within an operating temperature range. The fan controller controls the fan speed according to predetermined thermal profile settings associated with one of the compute modules received in the chassis. For example, the predetermined thermal profile settings may include a minimum fan speed, a maximum fan speed, and control loop feedback settings.

Abstract: A method and apparatus for substantially preventing recirculation of heated air from an exhaust outlet of an expansion card to an air inlet of the expansion card, wherein the air inlet and exhaust outlet are both on the same end of the chassis. The apparatus comprises a chassis with a chassis fan, a motherboard within the chassis having an expansion card connector, and an expansion card in communication with the expansion card connector and secured to the front end of the chassis. The expansion card also includes a card fan configured to move cooling air through the air inlet to the exhaust outlet. An air duct redirects the hot air from the exhaust outlet to prevent recirculation into the expansion card and causes the heated air to exit through the chassis fan. The air duct may include a longitudinal segment through a computer module and a lateral segment selectively securable over the exhaust outlet.

Abstract: Method and apparatus for substantially preventing recirculation of heated air from an exhaust outlet of an expansion card to an air inlet of the expansion card, wherein the air inlet and exhaust outlet are both on the same end of the chassis. The apparatus comprises a chassis with a chassis fan, a motherboard within the chassis having an expansion card connector, and an expansion card in communication with the expansion card connector and secured to the front end of the chassis. The expansion card also includes a card fan configured to move cooling air through the air inlet to the exhaust outlet. An air duct redirects the hot air from the exhaust outlet to prevent recirculation into the expansion card and causes the heated air to exit through the chassis fan. The air duct may include a longitudinal segment through a computer module and a lateral segment selectively securable over the exhaust outlet.

Abstract: A system comprising a chassis that includes a plurality of modules and a fan assembly disposed in a distal end of the chassis for drawing air in parallel pathways through the plurality of modules. At least one of the modules is a compute module having a thermal sensor disposed to sense the temperature of air flowing across a processor mounted on a motherboard. The system further comprises a fan controller receiving output from the thermal sensor, wherein the fan controller operates the fan assembly to cool the plurality of modules and maintain the thermal sensor output within an operating temperature range. The fan controller controls the fan speed according to predetermined thermal profile settings associated with one of the compute modules received in the chassis. For example, the predetermined thermal profile settings may include a minimum fan speed, a maximum fan speed, and control loop feedback settings.

Abstract: A computer system and method for measuring air density in a computer chassis. The computer chassis includes a fan, an ambient air temperature sensor, and a heat-generating device with a heat sink, a heat sink temperature sensor, and a controller. The controller controls the fan speed and applies a known amount of thermal energy to the heat sink, then determines the air density from the difference in temperature between the ambient air and the heat sink. The controller may then use the air density determination to adjust the air flow rate through the computer chassis to provide a proper air flow rate for cooling.

Abstract: An apparatus comprising a chassis providing a plurality of module bays, one or more modules received in the module bays, wherein each module has at least one damper actuator extending from a distal end of the module. A fan assembly and a plurality of air flow dampers are secured in a distal end of the chassis, wherein each damper is aligned with one module bay to control air flow through the aligned module bay. Each damper is biased to close in the absence of contact with a damper actuator and opens in response to contact with a damper actuator. Each damper opens to a variable extent determined by the profile of the contacting damper actuator. The damper actuator of a particular module has a profile corresponding to the thermal load of that module, such that installing a module into the chassis automatically opens the aligned damper to the desired extent.

Abstract: An apparatus comprising a chassis providing a plurality of module bays, one or more modules received in the module bays, wherein each module has at least one damper actuator extending from a distal end of the module. A fan assembly and a plurality of air flow dampers are secured in a distal end of the chassis, wherein each damper is aligned with one module bay to control air flow through the aligned module bay. Each damper is biased to close in the absence of contact with a damper actuator and opens in response to contact with a damper actuator. Each damper opens to a variable extent determined by the profile of the contacting damper actuator. The damper actuator of a particular module has a profile corresponding to the thermal load of that module, such that installing a module into the chassis automatically opens the aligned damper to the desired extent.

Abstract: A temperature isolation duct in a computer system comprising a chassis securing a circuit board and a fan system, wherein the fan system draws air through the chassis in an airflow direction, and a heat-generating component is mounted on the circuit board and exposed to the air flow. The hot air duct passively directs air heated by the heat-generating component from a single hot air duct inlet in direct downstream alignment with the heat-generating component to a single hot air duct outlet, wherein the hot air duct has a length to width aspect ratio of greater than four. A first thermal sensor is secured within, or direct alignment with, the hot air duct near the duct outlet for sensing the temperature of air flowing through the hot air duct and generating a first temperature signal. A controller is in electronic communication with the first thermal sensor for receiving the temperature signal and in electronic communication with the fan system for sending a fan speed control signal.

Abstract: Systems and methods provide altitude-dependent fan control for a plurality of electronic subsystems using a shared air pressure sensor. Each server or multi-server chassis of a rack system is a subsystem of the rack system. Each subsystem receives its own on-board fan or blower module. The shared air pressure sensor senses air pressure and outputs a signal to all of the subsystems. Each subsystem then independently regulates its own fan speed according to the signal output by the shared air pressure sensor. Other fan operational parameters, such as the number of fans recruited, may also be controlled according to altitude according to the invention. A variety of other performance parameters, such as internal air or component temperature, ambient air temperature, server workload, and processor activity level, may also be factored into control of these fan operational parameters.