Method and apparatus for controlling the temperature of components
A method and apparatus for the temperature control of a component within a storage system wherein the storage system includes a heat exchanger in thermal communication with the component to control the temperature of the component. One method includes: generating a flow of heat transfer fluid through the heat exchanger to transfer heat to or from the heat exchanger; receiving a set point signal indicative of the desired temperature of the component in the storage system; receiving temperature data regarding the component and the heat transfer fluid, and generating an output signal to control the flow of heat transfer fluid. The heat transfer fluid may be a gas or liquid.
1. A method comprising:
generating a flow of heat transfer fluid past a component present within a storage system, to transfer heat between the component and the heat transfer fluid;
receiving a set point signal indicative of a desired temperature of the component;
measuring temperature data of the heat transfer fluid; generating an output signal using a proportional, integral and derivative (“PID”) controller modified to use a factor that depends on the set point signal and the temperature data; and
controlling the flow of heat transfer fluid past the component based on the output signal.
2. The method according to claim 1 , wherein the storage system includes therein a heat exchanger in thermal communication with the component and wherein the heat transfers between the heat transfer fluid and the heat exchanger.
3. The method according to claim 1 , in which the temperature data includes a first temperature of the heat transfer fluid upstream of the component and a second temperature of the heat transfer fluid downstream of the component.
4. The method according to claim 3 , wherein generating the output signal comprises using a factor that depends on an error signal, on the first temperature, and on the second temperature.
5. The method according to claim 1 , wherein generating the output signal comprises determining the output signal based on a flow rate of the heat transfer fluid.
6. The method according to claim 1 , wherein the heat transfer fluid is a gas and the flow is generated with a fan.
7. The method according to claim 6 , further comprising determining a required fan speed and determining whether the required fan speed is an allowed fan speed;
if the required fan speed is an allowed fan speed, then operating the fan at the required fan speed;
if the required fan speed is not an allowed fan speed, then operating the fan at a different speed than the required speed.
8. The method according to claim 1 , wherein the heat transfer fluid is a liquid and the flow is generated with a liquid pump.
9. The method according to claim 8 , further comprising determining a required pump speed and determining whether the required pump speed is an allowed pump speed;
if the required pump speed is an allowed pump speed, then operating the liquid pump at the required speed;
if the required pump speed is not an allowed pump speed, then operating the liquid pump at a different speed than the required speed.
10. The method according to claim 1 , wherein generating the output signal comprises using a factor that depends on a rate of temperature change of the component.
11. The method according to claim 1 , further comprising receiving a signal indicative of a temperature of the component, and using the signal to determine the output signal.
12. The method according to claim 11 , wherein the signal indicative of the temperature of the component is obtained directly by measuring the temperature of the component using a temperature sensor.
13. The method according to claim 11 , wherein the signal indicative of the temperature of the component is estimated from the temperature data.
14. The method according to claim 11 , wherein a change δF in the flow rate of the heat transfer fluid is determined in accordance with the equation:
δ
F
=
K
P
2
F
T
O
-
T
I
(
T
C
-
T
S
)
+
K
D
2
M
(
T
C
-
T
I
)
(
T
O
-
T
I
)
2
ⅆ
T
C
ⅆ
t
+
K
T
2
F
T
O
-
T
I
δ
T
I
in which,
F is a heat transfer fluid flow rate;
T C is a measured component temperature;
T S is a set point temperature;
T I is a first temperature of the heat transfer fluid upstream of a heat exchanger;
T O is a second temperature of the heat transfer fluid downstream of the heat exchanger;
and
K P , K D , K T and M are constants.
15. The method according to claim 1 , further comprising having a plurality of components and the component is a control component j.
16. The method according to claim 15 , wherein a change δF in the flow rate of the heat transfer fluid is determined in accordance with the equation:
δ
F
=
K
Pj
2
F
T
Oj
-
T
Ij
(
T
Cj
-
T
Sj
)
+
K
Dj
2
M
j
(
T
Cj
-
T
Ij
)
(
T
Oj
-
T
Ij
)
2
ⅆ
T
Cj
ⅆ
t
+
K
Tj
2
F
T
Oj
-
T
Ij
δ
T
Ij
in which
F is the heat transfer fluid flow rate at a fan or pump;
T Cj is a measured temperature for the component j;
T Sj is a set point temperature for the component j;
T Ij is a temperature of the heat transfer fluid upstream of the component j;
T Oj is a temperature of the heat transfer fluid downstream of the component j; and
K Pj , K Dj , K Tj and M j are constants for the component j.
17. A method of cooling a component in a system, the method comprising:
providing the component at a temperature Tc, the component having a heat capacity H;
providing a coolant in thermal contact with the component at a flow rate, the coolant having a specific heat capacity C A ;
recording an initial coolant temperature T I upstream of the component;
after recording the initial coolant temperature T I , transferring heat from the component to the coolant;
measuring with a sensor a heated coolant temperature T O downstream of the component after transferring heat between the component and the coolant;
determining by a controller a required change δG in the coolant flow rate G to compensate for the dissipation of heat using the equation:
δ
G
≈
2
H
(
T
C
-
T
I
)
C
A
(
T
O
-
T
I
)
2
ⅆ
T
C
ⅆ
t
to determine δG; and
modifying the coolant flow rate G by the controller based on the determined δG.
18. The method according to claim 17 , comprising, prior to determining the value of δG, determining a value for H using the following steps:
allowing the system to stabilize;
using a flow rate register, allowing the flow rate register to contain a value F M ;
noting the values of T I and T O and renaming the values T I and T O T Ia and T Oa , respectively;
changing a power being dissipated in the component by an amount W M ; and
observing an immediate rate of change (RC) of the temperature of the component, where the value of H is then given by the equation
H
=
W
M
R
C
.