Patent Application
20090034187
Many electronic devices, such as personal computers and servers, house internal fans that provide airflow used to expel heat generated during operation. Proper airflow (e.g., fan operation) often requires some predetermined difference in air pressure between one side of the electronic device (i.e., a front side of the fan) and another side of the electronic device (i.e., a rear side of the fan). When such electronic devices are deprived of suitable differences in air pressure, the required airflow may be compromised and the electronic device containing the fan may be susceptible to an unwanted shutdown, reduced reliability or damage from overheating.
Such electronic devices may be stored in equipment containers (e.g., server racks). Many equipment containers contain cooling systems that are used to remove heat generated by electronic devices housed therein. Specifically, these equipment containers may be sealed (i.e., virtually airtight for the purpose of cooling) and may be cooled using fans and air-to-liquid heat exchangers. However, such sealed containers often cause unsuitable air pressure differences to develop between different sides of the electronic devices housed inside, thereby compromising fan operation inside the electronic devices and resulting in unwanted shutdown, reduced reliability or damage to the electronic devices.
For a detailed description of exemplary embodiments of the invention, reference will now be made to the accompanying drawings in which:
a shows a flow diagram of an illustrative method implemented in accordance with various embodiments; and
b shows a flow diagram of another illustrative method implemented in accordance with various embodiments.
Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, companies may refer to a component by different names. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ” Also, the term “couple” or “couples” is intended to mean either an indirect, direct, optical or wireless electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, through an indirect electrical connection via other devices and connections, through an optical electrical connection, or through a wireless electrical connection.
The following discussion is directed to various embodiments of the invention. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment.
Disclosed herein are various techniques by which air pressures within equipment containers may be regulated to prevent heat-related damage to electronic devices housed within the equipment containers.
The electronic device 110 may be housed within one of the plurality of containers 200 shown in
In accordance with various embodiments, the equipment container 100 comprises one or more pressure monitors. As shown in the illustrative embodiment of
The detectors 132 and 134 detect the air pressure of their respective environments (i.e., locations within the conduit 119), convert the detected air pressures into electrical signals, and transfer the signals to the pressure monitor 116. In turn, the pressure monitor 116 determines a difference between the air pressures detected by the detectors 132 and 134 and transfers a signal encoding this difference to the (A/D) converter 120. The A/D converter 120 converts signals received from the pressure monitor 116 to digital signals. These digital signals are provided to control logic 122 via connection 144. Based on the difference in pressure detected between the detectors 132 and 134, and further based on a predetermined target pressure difference stored in the controller 122, the control logic 122 may adjust, or cause the adjustment of, the speed of the fan 114. For example, if the target pressure (e.g., the pressure at detector 134 minus the pressure at detector 132) difference is greater than the pressure difference detected by the monitor 116 (i.e., using the detectors 132 and 134), the control logic 122 may decrease the speed of fan 114, thereby decreasing the air pressure near the front side 115 of the device 110 and increasing the air pressure near the rear side 117 of the device 110. In this way, the difference in air pressures is moved closer to the target pressure difference stored in the control logic 122. Alternatively, if the target pressure difference is less than the pressure difference detected by the monitor 116, the control logic 122 may increase the fan speed, thereby increasing the air pressure near the front side 115 of the device 110 and decreasing the air pressure near the rear side 117 of the device 110.
The control logic 122 may adjust the speed of the fan 114 by providing adjustment signals to the fan controller 124 (via connection 146) which, in turn, increases or decreases the speed of the fan 114 (via connection 148) in accordance with the adjustment signals. Although
In some embodiments, the equipment container 100 comprises a pressure-sensitive door 139. Unlike the doors 106 and 108, the door 139 is used to monitor air pressure within the duct 119 and to adjust the speed of the fan 114. The door 139 may be of any size, shape, etc. as long as its physical characteristics render the door 139 usable for the purposes described below. The door 139 couples to a hinge 147. As indicated by arrow 141, the door 139 is capable of opening outward (i.e., away from the duct 119). The door 139 is described as being “pressure-sensitive” because the door 139 opens when air pressure within the duct, and especially near the front side 115 of the electronic device 110, reaches some predetermined threshold. The predetermined threshold air pressure that causes the door 139 to open depends on the physical characteristics of the door 139, the tightness with which the door 139 couples to the hinge 147, etc. Accordingly, the door 139 and the hinge 147 may be designed such that the door 139 opens when a desired air pressure forms against the door 139 inside the duct 119. In some embodiments, the hinge 147 may comprise a spring and, thus, the threshold air pressure may be associated with the physical characteristics (e.g., weight) of the door 139 as well as the spring constant of the spring.
When the threshold pressure applied against the door 139 from within the duct 119 reaches the predetermined air pressure threshold, the door 139 opens and an alert apparatus 145 generates and transfers an alert signal to the control logic 122 via connection 143. The alert apparatus 145 may comprise any suitable mechanism, such as a switch, which generates an alert signal when the door 139 opens. This alert signal alerts the control logic 122 that the air pressure against the door 139 within the duct 119 has exceeded the predetermined air pressure threshold and, in turn, the control logic 122 may cause the fan speed controller 124 to adjust the air pressure within the duct 119 by adjusting the speed of the fan 114. For example, if a target air pressure near the front side 115 of the electronic device 110 is 0.5 pounds per square inch (psi), the pressure threshold may be set at 0.6 psi. Accordingly, when the air pressure pressing against the door 139 from within the duct 119 reaches 0.6 psi, the door 139 opens. The door may be of dimensions such that, when opened, air pressure within the duct 119 is not substantially affected. Stated otherwise, the size of the orifice created by the opening of the door is small enough so that the total airflow is not affected. Opening of the door causes an alert signal to be sent from the alert apparatus 145 to the control logic 122. In turn, the control logic 122 may cause the fan speed controller 124 to reduce the speed of the fan 114 just until the door 139 closes (i.e., until the alert apparatus 145 stops sending an alert signal or, alternatively, until the alert apparatus 145 sends a “stop” signal), thereby causing the air pressure near the front side 115 to drop to the target air pressure of 0.5 psi.
In some embodiments, the door 139 is included in the equipment container 100 with the pressure monitor 116 and pressure detectors 132 and 134. However, in other embodiments, the door 139 is included in the container 100 and the pressure monitor 116 and detectors 132, 134 are not included in the container 100. In yet other embodiments, the pressure monitor 116 and detectors 132, 134 are included in the container 100 but the door 139 is not included in the container 100.
a shows a flow diagram of an illustrative method 600 implemented in accordance with various embodiments. The method 600 begins by providing airflow from one side of the electronic device to another side of the electronic device via the duct (block 602). The method 600 then comprises determining air pressures at both sides of the electronic device (block 604). The method 600 also comprises determining whether the difference in air pressures is greater than a target difference (block 606). If so, the method 600 comprises decreasing the fan speed (block 608). Regardless, the method 600 further comprises determining whether the difference in air pressures is less than the target difference (block 610). If so, the method 600 comprises increasing the fan speed (block 612). Control of the method 600 then is provided to block 602. The steps of method 600 may be performed in any suitable, desired order.
b shows another illustrative method 650 implemented in accordance with various embodiments. The method 650 begins by providing airflow from one side of an electronic device to another side of the electronic device via a duct (block 652). The method 650 then comprises determining whether a pressure-sensitive door has opened (block 654). If so, the method 650 comprises decreasing the fan speed until the door closes and then maintaining that fan speed (block 656) and returning control of the method 650 to block 652. Otherwise, the method 650 comprises increasing the fan speed (block 658) and returning control of the method 650 to block 654. The steps of method 650 may be performed in any suitable, desired order.
The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.
