US2011236781A1PendingUtilityA1
Fuel cell cooling
Est. expiryOct 30, 2028(~2.3 yrs left)· nominal 20-yr term from priority
Inventors:Peter David Hood
H01M 8/04828H01M 8/04141H01M 8/04134H01M 8/04156H01M 8/04589H01M 2008/1095H01M 8/04485H01M 8/04291H01M 8/04044H01M 8/04029H01M 8/04F25D 29/00F25D 17/00Y02E60/50
62
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Claims
Abstract
A method of operating a fuel cell system ( 100 ) comprising a fuel cell stack ( 110 ) and a closed loop water cooling circuit for direct injection of cooling water into the stack ( 110 ), the method comprising: measuring an operational parameter of the fuel cell system ( 100 ) over a time period; adding an amount of water to the closed loop cooling circuit from the total amount of water generated during operation of the fuel cell stack ( 110 ) over the time period; and removing the amount of water from the closed loop cooling circuit generated during operation of the fuel cell stack ( 110 ) over the time period is automatically determined by the fuel cell system ( 100 ) as a function of the operational parameter.
Claims
exact text as granted — not AI-modified1 . A method of operating a fuel cell system comprising a fuel cell stack and a closed loop water cooling circuit for direct injection of cooling water into the stack, the method comprising:
measuring an operational parameter of the fuel cell system over a time period; adding an amount of liquid water to the closed loop cooling circuit from a total amount of water generated by the fuel cell stack during operation of the fuel cell stack over the time period; and removing the amount of liquid water from the closed loop cooling circuit, wherein the amount of liquid water as a proportion of the total amount of water generated during operation of the fuel cell stack over the time period is automatically determined by the fuel cell system as a function of the operational parameter.
2 . The method of claim 1 wherein the operational parameter is an electric current drawn from the fuel cell stack over the time period.
3 . The method of claim 2 wherein the proportion of the total amount of water removed from the closed loop cooling circuit is in proportion with the current drawn over the time period.
4 . The method of claim 1 wherein the operational parameter is the electrical conductivity of the water within the closed loop cooling circuit.
5 . The method of claim 1 wherein the operational parameter is the pH of the water within the closed loop cooling circuit.
6 . The method of claim 1 wherein the operational parameter is the total dissolved solids in the water within the closed loop cooling circuit.
7 . The method of claim 1 wherein the proportion of the total amount of water removed from the closed loop cooling circuit is a function of a difference between a predetermined set point and the operational parameter wherein the operational parameter is at least one of the electrical conductivity of the water within the closed loop cooling circuit, the total dissolved solids in the water within the closed loop cooling circuit and the pH of the water within the closed loop cooling circuit.
8 . The method of claim 1 wherein the amount of water is determined by controlling an outlet temperature of a heat exchanger in fluid communication with a cathode exhaust line of the fuel cell stack.
9 . The method of claim 8 wherein the outlet temperature of the heat exchanger is controlled by directing water removed from the closed loop cooling circuit on to an external surface of the heat exchanger.
10 . The method of claim 1 wherein the amount of water removed from the closed loop cooling circuit is determined by controlling operation of a pump in fluid communication with the closed loop cooling circuit.
11 . The method of claim 10 wherein the pump is operated intermittently with a duty cycle proportional to the amount of water to be removed from the cooling circuit.
12 . The method of claim 1 wherein the amount of water is calculated according to the relationship
W
r
=
β
In
2
F
moles
s
-
1
where W r is the amount of water to be removed from the cooling circuit, I is the current drawn from the fuel cell stack having n cells, F is the Faraday constant and b is a predetermined constant.
13 . The method of claim 12 in which b is approximately 0.1.
14 . A fuel cell system comprising a fuel cell stack, a closed loop water cooling circuit for direct injection of cooling water into the stack and a computerized controller, the controller being configured to automatically:
measure an operational parameter of the fuel cell system over a time period; add an amount of liquid water to the closed loop cooling circuit from the total amount of water generated during operation of the fuel cell stack over the time period; and remove the amount of liquid water from the closed loop cooling circuit, wherein the controller is configured to remove the amount of liquid water as a proportion of the total amount of water generated during operation of the fuel cell stack over the time period as a function of the operational parameter.
15 . The fuel cell system of claim 14 wherein the operational parameter is the electric current drawn from the fuel cell stack over the time period.
16 . The fuel cell system of claim 15 wherein the proportion of the total amount of water generated is in proportion with the current drawn over the time period.
17 . The fuel cell system of claim 14 wherein the operational parameter is the electrical conductivity of the water within the closed loop cooling circuit.
18 . The fuel cell system of claim 14 wherein the operational parameter is the pH of the water within the closed loop cooling circuit.
19 . The fuel cell system of claim 14 wherein the operational parameter is the total dissolved solids in the water within the closed loop cooling circuit.
20 . The fuel cell system of claim 14 wherein the proportion of the total amount of water ejected is a function of a difference between a predetermined set point and the operational parameter, the operational parameter being at least one of the electrical conductivity of the water within the closed loop cooling circuit, the total dissolved solids in the water within the closed loop cooling circuit and the pH of the water within the closed loop cooling circuit.
21 . The fuel cell system of claim 14 wherein the controller is configured to automatically control an outlet temperature of a heat exchanger in fluid communication with a cathode exhaust line of the fuel cell stack.
22 . The fuel cell system of claim 21 wherein the controller is configured to eject water from the closed loop cooling circuit on to the heat exchanger.
23 . The fuel cell system of claim 14 wherein the controller is configured to control the amount of water removed from the closed loop cooling circuit by controlling operation of a pump in fluid communication with the closed loop cooling circuit.
24 . The fuel cell system of claim 23 wherein the controller is configured to operate the pump intermittently with a duty cycle proportional to the amount of water to be removed from the cooling circuit.
25 . The fuel cell system of claim 14 wherein the controller is configure to automatically calculate the amount of water according to the relationship
W
r
=
β
In
2
F
moles
s
-
1
where W r is the amount of water to be removed from the cooling circuit, I is the current drawn from the fuel cell stack having n cells, F is the Faraday constant and b is a predetermined constant.
26 . The fuel cell system of claim 25 in which b is approximately 0.1.
27 . (canceled)
28 . (canceled)Join the waitlist — get patent alerts
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