Computer room air flow method and apparatus

[0002] The present application claims the benefit of U.S. Provisional Application Serial No. 60/226,887, filed Aug. 23, 2000 and is a continuation-in-part application of U.S. application Ser. No. 09/784,238, filed Feb. 16, 2001 now U.S. Pat. No. 6,494,050 (which claims the benefit of U.S. Provisional Application Serial No. 60/183,328, filed Feb. 18, 2000) and U.S. application Ser. No. 09/842,167 filed Apr. 26, 2001 now U.S. Pat. No. 6,412,292 (which claims the benefit of U.S. Provisional Application Serial No. 60/202,934, filed May 9, 2000), the disclosure of each of which is herein incorporated by reference.

[0003] 1. Field of the Invention

[0004] The present invention relates to a computer room reduced air flow method and apparatus but is not limited to use in computer rooms and instead can be utilized with respect to any equipment assembly requiring cooling which is positioned in a room. The method and apparatus described below permits achieving energy savings while reducing the amount of air required to cool electronic/heat generating equipment, wherein a computer rack heat extraction device (CRHED) or similar device is utilized. The method and apparatus permits the collection of heat generating, for example, by the rack electronic equipment.

[0005] 2. Discussion of the Background

[0006] A conventional computer room method and assembly is illustrated in FIG. 3 which exemplifies the approach for cooling electronic equipment commonly used currently wherein an array of racks of equipment are positioned on a raised floor. FIG. 3 illustrates an air-conditioning system used in the method and apparatus of a conventional system wherein a room space 1 defined by a room floor 2, side walls 3 and a ceiling 4 having a plurality of ceiling panels 4ais provided. The room floor 2 is positioned a predetermined distance above a base floor 5 such that the room floor 2 and the base floor 5 in combination form a double floor structure having a free space 6 (i.e., an air passageway) formed therein. A rack 7 for one or more computer processing units (CPUs) is disposed on the floor 2 wherein electronic cables for the rack are capable of being housed in the free space 6 of the double floor structure but can be specifically communicated to the rack separate from the free air space, if desired.

[0007] In installing each of the CPUs or other equipment on the rack of the floor, a plurality of support members 2bcan be provided which are stationary by being fixed by bolts or similar fastening elements to predetermined positions on the floor 2.

[0008] The rack 7 is positioned in a casing 8 having air inlets 8aand air outlets 8bformed respectively in a bottom plate of a casing 8 and in the ceiling portion of the casing 8. A computer case fan 9 is operable during operation of the equipment 7 so as to assist the air flow upwardly from the casing through the air outlets 8b. As shown in FIG. 3, the CPU members are arranged in an air passageway formed within the casing 8. The floor 2 includes a plurality of floor panels located on support members or pedestals 2b, one panel 2aof which includes a plurality of perforations to allow air flow as indicated by the arrows to flow through the front of the outside housing to casing 8, through the CPU rack 7 and out the back of casing 8. A cooling unit 14 is positionable either inside or outside the room 1 and is communicated with a heat exchanger or other air conditioning equipment so as to permit a cooling coil 15 located within unit 14 to cool air blowing there through. The cooling unit 14 also includes a fan 16 which is positionable below cooling coil 15. An inlet 20 is provided to allow air from the room to flow thereinto from the room, the air in the casing 8 mixing with room air prior to being introduced into the cooling unit 14, as illustrated in FIG. 3. The fan 16 is therefore arranged between the air inlet 20 and an air outlet 22 located at the lower portion of unit 14 and feeds air into the free space 6 located above the base floor. The fan 16 thus permits air in the interior of the room to be sucked into the air inlet 20 of the casing 8 and also permits the air in the room to pass through cooling coil 15. The air in the room is typically at a temperature of 75° F.±.

[0009] The above-noted approach for cooling electronic equipment thus permits the area in the free space 6 below the raised floor 2 to be used for cable management and also serves as a supply air plenum. The computer room air conditioning units (CRACUs) utilize cooling coil 15 to cool the air. The CRACUs supply conditioned air at approximately 55° F. to the underfloor supply air plenum or free space 6. The floor tiles with perforations or slots to allow air to flow from under the raised floor to above the floor are positionable below or are located adjacent to the rack 7. Other perforated tiles are positionable throughout the room to provide air supply to other heat generating equipment and to maintain the room at an ambient environment.

[0010] As illustrated by the arrows in FIG. 3 showing the air flow, the conditioned air is then drawn into the rack 7 by either convection by air flow from perforated panels 2aand/or opening 8ato the casing 8 or by fans 9 located in the top of the racks. The air enters the racks at a temperature of approximately 55° F., is heated by the CPUs or other electronic equipment, and flows upwardly out of the rack at approximately a temperature of 95° F. The warm air leaves the rack and mixes with the conditioned ambient environment of the room 1 which is at a temperature of approximately 75° F., and thus returns to the CRACUs at a temperature of approximately 75° F. as illustrated in FIG. 3.

[0011] Before the foregoing, it can be understood that a conventional CRACUs have a 20° delta T (±4° F.) across the cooling coil 15. This is also coincident with the space delta T which is defined as being the difference in temperature between the air supplied to the space and the air returned from such space. The temperature of the air returned from the space is usually coincident with the ambient space temperature such that the return air at 75° F. enters the return on top of the CRACUs, passes along the cooling coil 15 and is discharged at a temperature of substantially 55° F. at the bottom of unit 14 so as to pass into the free space 6. The required air quantity to cool such space is a direct function of the space delta T. The equation set forth below is used to calculate the required air flow or cubic feet per minute (CFM) of air to cool a space:

[0012] CFM=BTUH/1.08×delta T

[0013] From the foregoing, it can be appreciated that the disadvantage of the conventional system set forth above requires a significant amount of fan horsepower for operation and thus the need has arisen for reducing the amount of horsepower necessary to operate the fan 16.

[0014] Devices of the type described above are exemplified, for example, by U.S. Pat. No. 5,718,628; U.S. Pat. No. 4,774,631 and U.S. Pat. No. 5,910,045, the disclosure of each of which is herein incorporated by reference, as is the disclosure of parent application Ser. No. 09/784,238, the priority of which has been claimed in the present application.

[0015] The original concept by the inventors of the present application is exemplified by FIG. 4 of the present application. Such figure shows an air conditioning system used in a method and apparatus as described in such application. As shown therein, the room space is defined by room floor 2, sidewalls 3 and an upper ceiling 4 wherein a lower ceiling 4ais formed, for example, of ceiling tiles defining, a ceiling plenum 4b, and a base floor 5. The room floor 2 is formed a predetermined distance from the base floor such that the room floor 2 and the base floor 5 collectively form a double floor structure having a free space 6 or air passageway formed therein within which electric cables may also be housed. As shown in FIG. 4, air flow from space 6 can enter one side portion of each of the CPU racks and flow across the same towards a plenum 8cwhich can run the full length of the equipment assembly so as to permit air to flow across each CPU in the rack and then flow upwardly towards a plurality of ducts 24. The ducts 24 are sealed with respect to the equipment assembly by, for example, rubber gaskets wherein similar rubber gaskets 26 are provided between the duct 24 and the lower ceiling 4a. Also provided are computer case fans 24band 24c, if desired, to assist in air flow through the ducts 24.

[0016] FIG. 1 shows an air conditioning system use in the method and apparatus according to an additional earlier concept also developed by the inventors. As shown therein, the structure corresponding to that described above with regard to FIG. 3 utilizes the same reference numbers. In this regard, it is noted that the embodiment shown in FIG. 2 utilizes an attachment either on the back or top of the computer rack (or cabinet) to collect the warm air from the equipment in the rack. The apparatus as shown in FIG. 1, to the contrary, uses space available within the back and top of the rack for the same purpose wherein the use of the existing space allows for both space and cost efficiencies. The apparatus shown therein utilizes a cavity type front door 8 consisting of a solid outer panel 8fand a perforated plate inner panel 8b. Cooling air from below the raised floor 2 is directed first into an air plenum in the bottom of the rack. From the plenum, the cooling air is directed into the air space or cavity 8dand the door that extends the entire front of the rack 7. The air cavity channels the cool air and distributes the cool air more evenly across the front of the equipment in the rack 7. Therefore, this improvement in the distribution of air allows for more even cooling of the equipment.

[0017] The design shown in FIG. 1 also incorporates an air space or cavity 8ebetween the perforated plate 8band the front 7aof the equipment 7. This air space 8eallows for some re-circulated air to pass from the back 7bof the rack (i.e., the warm side) to the front 7aof the rack 7 (the cold side). Some recirculation may be required since the internal fans (not shown) in the equipment in the rack 7 may be moving more air than is supplied to the rack from the under-floor system described above. The above-noted design allows for either a single fan or a plurality of fans 25 at the top of the rack to exhaust the heat. The fan or fans 25 may be a single speed, variable speed or adjustable speed type of fan, depending upon the specific need for the device. FIG. 2 illustrates the manner in which perforated panel and the solid panels 8aand 8cat the front and back of the cabinet are pivotable so as to be opened for repair and/or replacement of the equipment in the rack 7. The flow arrow shown in FIG. 5 serves to illustrate the manner in which air flow occurs, including exiting of air into the ceiling plenum 4b.

[0018] An object of the present invention is to provide a method and apparatus which utilizes an increased delta T to reduce the required air quantity, thus resulting in a reduced airflow method and apparatus. Specifically, the present invention utilizes an approximately 40° F. delta T to reduce the CFM by substantially 50%. The substantially 50% reduction in the airflow will serve to effectively correspondingly reduce the required power by substantially 50%, resulting in substantial energy savings. A key element of the method and apparatus is an increase in delta T above what is conventionally used. The present invention is capable of operating in a range of delta T from 25° F. to 45° F. In this regard, it is noted that the use of a 40° F. in the description set forth below is solely exemplary in illustrating the device and greater or lesser temperature variations are possible.

[0019] An object of at least one embodiment of the present invention is to provide an air conditioning method and apparatus which utilizes the steps of supplying cooling air generated from a cooling apparatus into an air passageway formed below a floor; guiding the cooling air within the air passageway into an equipment assembly disposed on the floor through an opening located in the floor; communicating the cooling air introduced into the equipment assembly into a plenum and introducing the air released from within the equipment into the plenum for communicating such released air to the cooling apparatus. The method may also include the step of guiding the air from the equipment assembly through at least one duct into the plenum and may include the step of cooling the cooling air generated from the cooling apparatus to a temperature of substantially 55° F. while also heating the air released from the equipment assembly to a temperature of substantially 95° F. prior to introducing such air to the cooling apparatus so as to form a closed loop in terms of cycling of the air through the cooling assembly and the equipment assembly.

[0020] A further object of the present invention is to obtain a temperature differential between the air supplied to the air passageway or plenum from the cooling apparatus and the air introduced into the plenum from the equipment assembly so as to be substantially 40° F., thus permitting lower power requirements of the fan utilized to assist flow of the air in the closed loop.

[0021] A further object of the present invention is to position the fan between the cooling apparatus and the air passageway so as to permit blowing of the air into the passageway towards the equipment assembly, although it is understood that the fan can be located anywhere within the closed loop so as to assist flow of air between the blowing apparatus and the equipment assembly.

[0022] A further object of the present invention is to provide a method and apparatus wherein the cooling assembly is located either within or outside the computer room, the equipment assembly comprising either at least one computer processing unit or other type of processing unit in combination with an additional heat generating equipment or without such equipment. In addition, a further object, of the present invention is to cool equipment assembly generating heat which does or does not include computer equipment.

[0023] An additional object of the present invention is to provide an air conditioning assembly for performing the method described above.

[0024] An additional object of the present invention is to provide a CPU rack housing with a cavity type front door having a substantially solid outer panel and a perforated plate inner panel so that cooling air from below the raised floor is directed first into an air plenum in the bottom of the rack. From the plenum, the cooling air can be directed into an air space or cavity in the door that extends the entire front of the rack such that the air cavity channels cool air and distributes the cool air more evenly across the front of the equipment in the rack and thus allows for more even cooling of the equipment.

[0025] A further object of the present invention is to provide an improved design which incorporates an air space or cavity between the perforated plate and the front of the equipment so that the air space allows for some re-circulated air to pass from the back of the rack (the warm side) to the front of the rack (the cold side).

[0026] An additional object of the present invention is to permit either a single fan or a plurality of fans to be positioned at the top of the rack so as to exhaust the heat wherein the fan or fans have a single speed, variable speed or adjustable speed capability, depending upon the specific need for the device.

[0027] Another feature of the device is the ability to cool more heat generating electronic equipment in a cabinet than can be cooled with the conventional system. The conventional system as shown in FIG. 3 has been shown to experience overheating of equipment at conditions above 4 KW of name plated heat rejection of electronic equipment per cabinet. A cabinet equipped with the CRHED and associated improvements will effectively cool up to 8 KW of name plated heat rejection of electronic equipment. The ability to cool more equipment in a single cabinet result in more revenue per unit area of a building.

[0028] Yet an additional feature of the present invention is to provide a heating and cooling method in accordance with the above-noted objects wherein cooling air is fed to the heat generating electronic equipment in the cabinet by means of a cooling duct in the ceiling which permits air to be fed to the equipment at a temperature of substantially 55° F. which is thermally isolated from the remaining volume of the ceiling plenum itself which permits return of air via a duct from the heating equipment at a temperature of substantially 95° and which is returned to the heating and air conditioning system described above. This permits the cooling air to be fed to the equipment via the ceiling rather than via than the plenum provided beneath the floor and above the base floor.

[0029] It is yet an additional object of the present invention to provide a method and apparatus described in the foregoing paragraph but wherein the air upon being heated is returned via one or more fans from the electronic equipment and the heat is released into the room for return to the heating and air conditioning assembly. This embodiment permits the cooled air plenum provided in the ceiling duct to communicate cooled air at a temperature of substantially 55° F. into the equipment via a duct which permits heated air from the heat generating electronic equipment to exit from the cabinet of the equipment into the ceiling for return to the heating and air conditioning system for being cooled to a temperature of substantially 55° by the cooling unit 14 so as to complete the cycle of flow of air to and from the heat generating electronic equipment in the cabinet.

[0030] Various features, objects and attendant advantages of the preferred embodiments are illustrated in the figures of the present application which serve to explain the principles of the invention, wherein:

[0031] FIG. 1 illustrates an air conditioning method and apparatus used in an embodiment of the present invention previously developed by the inventors.

[0032] FIG. 2 is a top view of the structure shown in FIG. 1, which illustrates the capability of the panels to be pivotable on the cabinet.

[0033] FIG. 3 illustrates a conventional air conditioning method and apparatus; and

[0034] FIG. 4 illustrates a concept of the inventors designed for an air conditioning method and apparatus which was developed subsequent to the initial embodiment shown in FIG. 1.

[0035] FIG. 5 illustrates an air conditioning method and apparatus according to the present invention;

[0036] FIG. 6 is a top view of the structure shown in FIG. 5, which illustrates the capability of the panels to be pivotable on the cabinet.

[0037] FIG. 7 illustrates a second embodiment of the air conditioning method and apparatus in accordance with the present invention.

[0038] FIG. 8 is a top view of the structure shown in FIG. 7, which illustrates the capability of the panels to be pivotable on the cabinet.

[0039] FIG. 9 illustrates a third embodiment of the air conditioning method and apparatus used in the present invention; and

[0040] FIG. 10 is a top view of the structure shown in FIG. 9, which illustrates the capability of the panels to be pivotable on the cabinet.

[0041] FIGS. 5 and 6 illustrate the first embodiment in accordance with the present invention wherein structure similar to that shown in FIGS. 1-4 is illustrated using the same reference number but in a 100 series. FIGS. 5 and 6 serve to illustrate the air-conditioning system used in the method and apparatus of the present invention wherein a room space 101 is defined by a floor 102, side walls 103 and a ceiling 104 having a plurality of ceiling panels 104a. The room floor 102 is positioned a predetermined distance above the base floor 105 such that the room floor 102 and base floor 105 in combination form a double floor structure having a free space 106 (i.e. air passageway) formed therein. A rack 107 for one or more computer processing units (CPUs) is disposed in a casing 108 located on the floor 102 wherein electronic cables for the rack are capable of being housed in the free space 106 of the double floor structure but can be specifically communicated through the rack 107 separate from the free air space, if desired.

[0042] In installing each of the CPUs or other equipment on the rack on the floor, a plurality of support members can be provided which are stationary by being fixed by bolts or similar fastening elements to the predetermined positions on the floor 102.

[0043] The rack 107 is positioned in the casing 108 has the casing is provided with air inlets 108aand air outlets 108h. A computer case fan 125 is operable during operation of the rack 107 so as to assist the flow upwardly from the casing through the air outlets 108h. A cooling unit similar to that of cooling unit 14 illustrated in FIG. 4 is positionable either inside or outside the room 101 and is communicated with a heat exchange or other air conditioning equipment as previously described so as to permit the cooling coil 15 located within the unit 14 to cool air blowing therethrough. The cooling unit 14 also includes a fan 16 which is positionable below cooling coil 15 as shown in FIG. 4. Also shown in FIGS. 5 and 6 is the casing 108, inlet 108ain the form of an opening in the bottom part of the equipment for permitting air at substantially 55° to flow into the equipment, a perforated plate inner panel 108b, a rear wall 108cof the casing 108, and an air space or cavity 108dlocated between panel 108band the outer wall of the casing 108 and room space 101. In addition, a single fan or plurality of fans 125 is provided at opening 108h.

[0044] The embodiment shown in FIGS. 5 and 6 allows for heat rejected from the rack to be ventilated directly into the space of the computer room and allows the rack to be used in existing computer rooms. This improvement as well as the improvement shown in FIGS. 7-9 provide an improvement to the original design conceived by the present inventors and permits venting the heat directly into the room and supplying the air into the top or bottom portion of the computer room. Alternatively, as shown in FIGS. 7-8, the air can be returned to a ceiling plenum 104bto complete the air conditioning cycle.

[0045] The second embodiment of the present invention is shown in FIGS. 7 and 8 wherein an additional duct 104cis provided for directly communicating cooled air at a temperature of substantially 55° to an additional duct 108gthat directly leads into an opening 108aformed in the upper portion of the casing 108 as illustrated in FIG. 7. This permits air to flow downwardly and then pass through the perforated screen or plate 108bwhere the air is recycled back to the entrance portion 107aof the CPU rack and then subsequently be let out the outlet portion 107bthereof and to flow upwardly through opening 108hvia the use of one or more fans 125 and then to flow into duct 124 for communication of such heated air at a temperature of substantially 95° F. back into plenum 104bfor return of the cooling unit 14 illustrated in FIG. 4 of the present invention. As can be appreciated from a review of FIGS. 7 and 8, such differs from previous embodiments in that casing 108 can be positioned on the base floor 105 since no cooling air need flow through the bottom portion thereof. However, as can be contemplated by one of ordinary skill in the art, it would be possible to provide a similar plenum to that of 104cand to place it within a free space 106 as shown in FIG. 5 so as to supplement the heating and cooling accomplished in the manner shown in FIGS. 7 and 8.

[0046] The third embodiment shown in FIGS. 9 and 10 of the present invention includes a duct 104csimilar to that of FIGS. 7 and 8 but wherein duct 125 is removed and that, instead, a fan or plurality of fans 125 permit the heated air to be returned directly into the computer room 101 wherein the air exiting from the casing 108 exits with a CFM based upon a 40° F. ΔT load in cabinet 108.

[0047] Additional advantages and modifications readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details discussed above, and the illustrated examples shown and described therein may be formed of structurally equivalent elements. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.