Air flow controller for electrical equipment holder

Abstract

A fan is controlled to remove or provide air from or to an equipment enclosure as a function of a difference in pressure between a front and back of a rack of equipment.

1 . A method comprising:
 measuring a difference in air pressure between a first side of an equipment enclosure and a second side of the equipment enclosure, wherein some equipment mounted in the enclosure has self contained cooling mechanisms that cool based on convection; and   controlling the measured differential air pressure about a desired set point.   
   
   
       2 . The method of  claim 1  wherein the set point is zero. 
   
   
       3 . The method of  claim 1  wherein the difference in air pressure is measured by a differential pressure sensor having two tubes, a first tube having an opening positioned near the first side of the equipment enclosure and a second tube having an opening positioned near the second side of the equipment enclosure. 
   
   
       4 . The method of  claim 3  wherein at least one of the tubes comprises multiple tubes with opening positioned at different places to provide an average of the pressure at the first or second side of the enclosure. 
   
   
       5 . The method of  claim 1  wherein the differential air pressure is controlled by using a fan to remove air from the second side of the equipment enclosure. 
   
   
       6 . The method of  claim 1  wherein the differential air pressure is controlled by using multiple fans to remove air from the second side of the equipment enclosure. 
   
   
       7 . The method of  claim 6  wherein multiple fans are controlled as a function of measured difference in pressure between the first side of the enclosure and a corresponding point proximate each fan. 
   
   
       8 . The method of  claim 1  wherein the difference in air pressure is measured as a function of air pressure at multiple points in the first and second sides of the equipment enclosure. 
   
   
       9 . The method of  claim 1  wherein multiple wireless absolute pressure sensors are used to sense the difference in pressure. 
   
   
       10 . The method of  claim 1  wherein the first side of the equipment enclosure corresponds to front side of the equipment enclosure and the second side of the equipment enclosure corresponds to a back side of the equipment enclosure. 
   
   
       11 . The method of  claim 1  wherein the equipment enclosure comprises a two rows of racks of equipment having an enclosed aisle between the two rows of racks, and wherein the differential air pressure is controlled by using a fan to provide air to the enclosed aisle. 
   
   
       12 . A device comprising:
 a differential pressure sensor operable to sense a first pressure at a first side of an equipment rack in an enclosure and a second pressure at a second side of the equipment rack and provide a signal representing a difference between the first and second pressures;   a fan operable to add or remove air from the equipment enclosure; and   a controller coupled to the fan for receiving the signal from the differential pressure sensor and controlling the fan about a differential pressure set point.   
   
   
       13 . The device of  claim 12  wherein the first side of the equipment rack corresponds to a front side of the equipment enclosure. 
   
   
       14 . A system comprising:
 an equipment enclosure;   multiple pieces of equipment, each having a fan for cooling itself;   a differential pressure sensor operable to sense a first pressure at a first side of an equipment enclosure and a second pressure at a second side of the equipment enclosure and provide a signal representing a difference between the first and second pressure;   a fan supported by the equipment enclosure and operable to remove air from the second side of the equipment enclosure; and   a controller coupled to the fan for receiving the signal from the differential pressure sensor and controlling the fan about a differential pressure set point.   
   
   
       15 . The system of  claim 14  wherein the first side of the equipment enclosure corresponds to front side of the equipment enclosure and the second side of the equipment enclosure corresponds to a back side of the equipment enclosure. 
   
   
       16 . The system of  claim 15  wherein the pieces of equipment are supported within the enclosure such that air moves through them generally from the front of the enclosure to the back of the enclosure. 
   
   
       17 . The system of  claim 14  wherein the differential pressure set point is zero. 
   
   
       18 . A system comprising:
 a differential pressure sensor operable to sense a first pressure within an enclosed aisle separating two rows of racks of equipment and a second pressure at a side of one of the rows of racks opposite the enclosed aisle and provide a signal representing a difference between the first and second pressures;   a fan operable to provide air to the enclosed aisle or remove air from the enclosed aisle separating the rows of racks of equipment; and   a controller coupled to the fan for receiving the signal from the differential pressure sensor and controlling the fan about a differential pressure set point.   
   
   
       19 . The system of  claim 18  wherein the fan comprises a fan assisted floor tile. 
   
   
       20 . The system of  claim 18  wherein at least one of the equipment has a fan to cool itself.