# US 9,883,617 B2 · Air-conditioning control apparatus for data center

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- Number: US 9,883,617 B2
- Document ID: US9883617B2
- Status: Granted
- Kind: B2
- Application number: 14/191,986
- Filed: 2014-02-27
- Published: 2014-08-28
- Granted: 2018-01-30
- Earliest claimed: 2013-02-28
- Assignees: Hitachi, Ltd.
- Applicants: Hitachi, Ltd.
- Inventors: Hayato Shimizu
- Web page: https://patentgrep.com/patent/US9883617B2

## CPC

- H05K 7/20836: {Thermal management, e.g. server temperature control}
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

An air conditioning system having an inlet air temperature calculating block that calculates a variation in air temperature at an inlet port of each unit based on position information and also calculate the air flow rate through each unit. A temperature sensitivity calculating block calculates temperature sensitivity of each unit obtained by dividing the variation in air temperature at the inlet port by a variation in air temperature at an outlet port of each unit. An inlet air temperature calculating block calculates the air temperature at the inlet port of each unit on the basis of the air temperature at the outlet port of each unit, and the temperature sensitivity.

## Claims

### Claim 1

An air-conditioning control apparatus having a memory, a processor, and a storage device coupled thereto, the air-conditioning control apparatus being configured to:
calculate a variation ΔTin(i), where i=1 to N, in air temperature at an inlet port of an ith information-processing unit, where N is a total number of information processing units, based on position of the ith unit and an air flow rate through the ith unit, wherein the air flow rate through the ith unit is measured by a fan speed sensor operatively connected with the processor, and wherein the air flow rate through the ith unit is measured by a fan speed sensor operatively connected with the processor, and wherein the air temperature at the inlet port of the ith information-processing unit is measured by a first sensor operatively connected with the processor, wherein the first sensor is at least one of a first temperature sensor or a first infrared camera;
calculate a first temperature sensitivity a(l, j) by dividing the variation by a variation Tout(j), where j=1 to N, in air temperature at an outlet port of a jth unit, wherein the air temperature at the outlet port of the jth unit is measured by at least one of a second temperature sensor operatively connected with the processor or a second infrared camera operatively connected with the processor;
calculate a first temperature sensitivity a(i, j) by dividing the variation ΔTin(i) by a variation Tout(j), where j=1 to N, in air temperature at an outlet port of a jth unit, based on the position of the jth unit and an air flow rate through the jth unit, wherein the air flow rate through the jth unit is measured by a second fan speed sensor operatively connected with the processor, wherein the air temperature at the outlet port of the jth unit is measured by a second sensor operatively connected with the processor, wherein the second sensor is at least one of a second temperature sensor or a second infrared camera;
calculate an air temperature ΔTin(i) at the inlet port of the ith unit based on an air temperature Tout (j) at an outlet port of the jth unit and the calculated first temperature sensitivity a(i, j);
determine a maximum value M of the temperature ΔTin(i); and
control a temperature setting of at least one air conditioner to prevent the maximum value M from exceeding a predetermined threshold value.

### Claim 2 (depends on 1)

The air-conditioning control apparatus according to claim 1, further configured to:
calculate a second temperature sensitivity astat(i, j) of a first measured temperature TSin(i) of air at the inlet port of the ith unit, as received from the first sensor, and a second measured temperature TSout(j) of air at the outlet port of the jth unit, as received from the second sensor.

### Claim 3 (depends on 2)

The air-conditioning control apparatus according to claim 2, further configured to:
update the first temperature sensitivity a(i, j) that has been stored into the storage device to the second temperature sensitivity astat(i, j) when a difference between the first temperature sensitivity a(i, j) and the second temperature sensitivity astat(i, j) is greater than or equal to a predetermined threshold value.

### Claim 4 (depends on 3)

The air-conditioning control apparatus according to claim 3, further configured to:
allocate loads between information-processing units.

### Claim 5 (depends on 2)

The air-conditioning control apparatus according to claim 2, further configured to:
calculate a heat transfer rate Q2(i) through the ith unit based on a mass flow rate and specific heat of air;
calculate an air flow temperature sensitivity astat(i, j, Q2) based on the heat transfer rate Q2 (i) and the second temperature sensitivity astat(i, j); and
update the temperature sensitivity a(i, j) that has been stored into the storage device to the air flow temperature sensitivity astat(i, j, Q2) when the difference between the temperature sensitivity a(i, j) and the air flow statistical temperature sensitivity astat(i, j, Q2) is greater than or equal to a predetermined threshold value.