METHOD AND APPARATUS FOR EFFICIENTLY COORDINATING DATA CENTER COOLING UNITS

• US 20110203785A1
• Filed: 08/20/2010
• Published: 08/25/2011
• Est. Priority Date: 08/21/2009
• Status: Active Grant

• Current Assignee: Vigilent Corporation
• Original Assignee: Federspiel Corp
• Inventors: Chin, Jerry, Federspiel, Clifford C., Federspiel, Kurt
• Granted Patent: US 8,634,962 B2
• Time in Patent Office: Days
• US Class Current: 165/200
• CPC Class Codes: G05D 22/02 characterised by the use of electric means
• CPC Class Codes: G05D 23/1928 sensing the temperature of one space
• CPC Class Codes: H05K 7/20745 within rooms for removing heat from cabinets, e.g. by air conditioning device
• CPC Class Codes: H05K 7/20836 Thermal management, e.g. server temperature control

Abstract

Systems, apparatus, and methods for controlling environmental maintenance modules (e.g. HVAC units) using sensors are provided. Values measured by the sensors can be used to determine a change in operation levels of the modules to keep the sensor values within a desired range. For example, a stopped module can be increased or started for more cooling when a sensor temperature is too hot. The module predicted to have the greatest effect on the temperature of hot sensor can be started. A transfer matrix, which provides a relation between a change in operation level and resulting sensor changes, can be used to perform the above predictions. As another example, a module can be stopped (or otherwise have an operation level decreased), if the sensor temperatures are within range, and the decrease in operation level is predicted not to cause an out-of-range condition.

Claims

1. A method of controlling an environmental maintenance system including a plurality of environmental maintenance modules and a plurality of sensors that measure a value of a physical condition of an environment, the method comprising:

identifying a sensor S_indx whose sensor value is measured to be outside of a range;

for each of at least a portion of the modules, determining a predicted change value that predicts an extent that changing an operation level of the respective module changes the sensor value measured by the identified sensor S_indx;

selecting at least one module based on the predicted change values; and

changing the operation level of the selected module to effectuate a change of the sensor value of sensor S_indx.

2. The method of claim 1, wherein the change of operation level is starting or stopping the module.

3. The method of claim 1, wherein determining a predicted change value for a first module includes determining a predicted change value for a change in operation level of each of a plurality of actuators corresponding to the first module.

4. The method of claim 1, wherein the change of operation level is increasing an operation level of the selected module, wherein the selected module was previously running before the change, and wherein the measured sensor value is outside of a range when the measured sensor value is above a threshold value or below a threshold value.

5. The method of claim 1, wherein the module with the largest predicted change value has its operation level changed.

6. The method of claim 1, wherein selecting a module includes:

identifying the predicted change values that are greater than a change threshold; and

selecting one of the modules whose predicted change value is greater than the change threshold.

7. The method of claim 6, wherein if at least one of the modules has a predicted change value greater than the change threshold and has a variable fan speed, then a module with a variable fan speed is selected for changing the operation level.

8. The method of claim 6, wherein selecting one of the modules is performed randomly.

9. The method of claim 1, wherein a predicted change value for a module S_indx corresponds to Y_post−

Y_pre, which is determined as Y_post−

Y_pre=TM(H_indx,S_indx)*Δ

level_est(S_indx), where Y_post is the estimated sensor value of the identified sensor H_indx after changing the operation level of module S_indx, Y_pre is the sensor value of the identified sensor H_indx before changing the operation level of module S_indx, Δ

level_est(S_indx) is an estimated amount of change in the operation level of the module S_indx to be enacted, and wherein TM is a transfer matrix that provides a relation between changing an operation level of a module and resulting changes in sensor values.

10. The method of claim 9, wherein the change of the operation level of module S_indx is a start, wherein N modules are running prior to module S_indx being started, and wherein the estimated operation level of the module S_indx after starting is an average of the operation levels of the operating modules times N/(N+1).

11. The method of claim 9, further comprising updating the transfer matrix TM by:

measuring first sensor values Y1 of the sensors and determining the operation level of the selected modules before changing its operation level;

after changing its operation level, measuring second sensor values Y2 of the sensors and determining the operation level of the selected module;

calculating

12. The method of claim 11, wherein the updated TM is obtained from TM_NEW and the old TM using the equation

TM(i, j)_updated=g*TM(i, j)_new+(1−

g)*TM(i, j)_old, where g is between 0 and 1.

13. The method of claim 1, further comprising preventing changing an operation level of another module until a predetermined amount of time elapses after the selected module has its operation level changed or until a quasi-steady state condition is achieved after the selected module has its operation level changed.

14. A computer program product comprising a tangible computer readable medium storing a plurality of instructions for controlling a processor to perform an operation for controlling an environmental maintenance system including a plurality of environmental maintenance modules and a plurality of sensors that measure a value of a physical condition of an environment, the instructions comprising the method of claim 1.

15. An environmental maintenance system comprising:

a plurality of environmental maintenance modules;

a plurality of sensors that measure a value of a physical condition of an environment;

the computer program product of claim 13; and

at least one processor.

16. A method of controlling an environmental maintenance system including a plurality of environmental maintenance modules currently running and a plurality of sensors that measure a value of a physical condition of an environment, the method comprising:

for at least one of the plurality of the modules currently running;

estimating sensor values of the sensors resulting if an operation level of the module were decreased by at least a predetermined amount;

determining a first set of one or more of the plurality of the modules currently running that have none of the estimated sensor values outside of a first range; and

decreasing an operation level of at least one module of the first set in response to the determination that one or more of the plurality of the modules currently running have none of the estimated sensor values outside of the first range.

17. The method of claim 16, wherein decreasing an operation level of at least one module of the first set includes stopping a module.

18. The method of claim 16, wherein estimating sensor values of the sensors resulting if an operation level of a first module were decreased by at least a predetermined amount includes:

estimating resulting sensor values for a change in operation level of each of a plurality of actuators corresponding to the first module, and wherein decreasing an operation level corresponds to decreasing the operation level for the actuator that does not cause estimated sensor values to be outside of the first range.

19. The method of claim 16 wherein the first range includes a threshold that is a combination of a target threshold minus a deadband value.

20. The method of claim 16, further comprising:

identifying one or more modules of the first set whose efficiency is less than an efficiency threshold; and

for one of the identified running modules;

estimating a percent capacity of each module that would remain on if the identified module were shut off, the percent capacity being a measure of the percentage of the designed capacity at which the identified module is operating;

determining a load from the percent capacities;

determining whether the load does not exceed a first threshold;

decreasing the operation level the identified module in response to a determination that the load does not exceed the first threshold and none of the estimated sensor values are outside of the first range.

21. The method of claim 20, wherein the one of the identified modules is the identified module with the lowest efficiency.

22. The method of claim 20, wherein the load is determined from the percent capacity of each module and a design capacity of the module.

23. The method of claim 20 wherein the estimated percent capacity % Cap of module C_indx is % Cap(Cindx)=% Cap(Cindx)+LOAD(Cindx, Sindx)*% Cap(Sindx),

wherein the load matrix provides a measure of the effect of stopping a module on the capacity of use of the remaining modules that remain on, wherein the load matrix element LOAD (C_indx, S_indx) provides a measure of the effect of stopping module S_indx on the capacity of module C_indx.

24. The method of claim 20, wherein the efficiency η

for module C_indx is computed as the percent capacity divided by the percentage of operation of a fan speed relative to a maximum fan speed setting.

25. A method of initializing an environmental maintenance system that includes a plurality of environmental maintenance modules and a plurality of sensors that measure a value of a physical condition of an environment, each module including one or more actuators, the method comprising:

receiving a first sensor value Y1 for each of the sensors;

changing an operation level of at least two actuators of the modules at a same time;

for each sensor;

after the change in operation levels, receiving a second sensor value Y2; and

calculating a difference between the first sensor value Y1 and the second sensor value Y2; and

determining at least a portion of matrix elements of a transfer matrix based on the differences, the transfer matrix having dimensions of a number of actuators by a number of sensors, wherein the portion includes matrix elements associated with the at least two actuators, and wherein determining a matrix element for sensor S and actuator P includes;

determining a first ratio having a numerator including the difference for sensor S and having a denominator including the change in operation level for actuator P; and

combining the first ratio with at least one other ratio, wherein the at least one other ratio is determined from a previous change of the operation level of actuator P that resulted in a previous difference in the sensor values for sensor S.

26. The method of claim 25, wherein combining the first ratio with at least one other ratio includes using a recursive least squares.

27. The method of claim 25, wherein the change in operation level of an actuator of a module is starting or stopping the respective module.

28. The method of claim 25, wherein combining the first ratio with at least one other ratio includes:

determining an error of the calculated difference relative to a predicted change in the sensor value for sensor S due to the change in operation level of actuator P; and

adding the error to the existing value for the matrix element for sensor S and actuator P, wherein the existing value was determined from the previous difference and previous change in the operation level of actuator P.

29. The method of claim 28, further comprising:

multiplying the error by a learning factor prior to the adding, wherein the learning factor is determined from a covariance matrix.

30. A method of initializing an environmental maintenance system that includes a plurality of environmental maintenance modules and a plurality of sensors that measure a value of a physical condition of an environment, the method comprising:

at least one processor determining a transfer matrix TM by;

for each one of the modules;

receiving a first sensor value Y1 for each of the sensors, each first sensor value being received when the respective module has a first operation level;

stopping or starting the respective module; and

after stopping or starting the respective module, for each sensor;

receiving a second sensor value Y2;

calculating a difference between the first sensor value Y1 and the second sensor value Y2; and

calculating a TM matrix element using the difference,

wherein the transfer matrix TM provides a relation between starting and/or stopping a module and resulting changes in the sensor values for each sensor.

31. The method of claim 30, wherein the matrix element equals (Y2−

Y1) divided by a measure of capacity.

32. The method of claim 31, further comprising:

receiving a return temperature TR_s and a discharge temperature TD_s for each module S when all modules are running, wherein the operation level is a capacity measured by

33. The method of claim 30, further comprising:

calculating a load matrix by;

for each respective module S_indx;

for each other module C_indx, calculating a percent change in capacity (Δ

% Cap) that results from changing the operation level of the respective module S_indx; and

using each percent change to determine a load matrix element LOAD(C_indx, S_indx),

wherein the load matrix provides a measure of the effect of changing the operation level of a module on the capacity of use of the remaining modules that remain on.

34. The method of claim 33, wherein

35. The method of claim 34, where