COOLING A HYDROGEN FUEL CELL

Abstract

A system (100) for vaporizing hydrogen to supply hydrogen in gaseous form to a plurality of hydrogen fuel cells comprises: an evaporator; a cooler (108) configured to cool a cooling fluid in a cooling system for the plurality of hydrogen fuel cells; a spray supply system (114) comprising: a tank; a pump configured to pump water from the tank; a nozzle system; and a condensate tray (116) configured to collect condensate and return the condensate to the tank. The system (100) is configured to activate the pump to pump the condensate collected in the tank to cool the cooler (108) based on the temperature of the cooling fluid.

Description

Technical field

[0001] The present disclosure relates generally to the cooling of hydrogen fuel cells and in particular to the cooling of hydrogen fuel cells using liquid hydrogen. State of the art

[0002] A fuel cell (e.g., a proton exchange membrane fuel cell (PEMFC)) uses chemical energy, usually from hydrogen, to generate clean and efficient electrical energy. When hydrogen is used as the working fuel, the fuel cell will only produce electricity, water, and heat. Fuel cells are therefore advantageous in a wide range of applications due to their ability to provide electrical power. They can be used to power large power plants, server farms, and large industrial facilities, as well as smaller applications such as personal computers.

[0003] In a fuel cell-based power system, the heat emitted by the fuel cells can be absorbed by a coolant system designed to cool them. This heat dissipation can account for more than half of the chemical energy generated by the fuel cells. A stack of fuel cells requires significant cooling to achieve optimal operating temperatures in the range of 60-65 degrees Celsius. Cooling to this level can pose a significant challenge, especially in environments where equipment must be cooled from ambient temperatures of up to 50 degrees Celsius.

[0004] However, even in environments with high ambient temperatures, systems for cooling fuel cell stacks can utilize certain environmental conditions. For example, cooling systems can use ambient temperatures and humidity, along with waste heat, to evaporate liquid hydrogen, a necessary component for the fuel cell reaction. They can then use this evaporation to condense the liquid in the air and collect it to cool the fuel cell stack.

[0005] Japanese patent document JP 4839514 B2 (“the '514 Reference”) describes fuel cells used to generate electrical power through the chemical reaction of hydrogen and oxygen. The fuel cells are cooled by a system comprising a heat transfer fluid flow path located outside the fuel cell, the flow path circulating a cooling medium within the fuel cell. The system further includes a cooler interposed in the heat transfer fluid flow path to dissipate heat from the cooling medium to the atmosphere and cool the cooling medium, as well as a fan that blows air onto the cooler. The system also includes a gas-liquid separator located outside the fuel cell, into which water and water vapor generated by the chemical reaction within the fuel cell are introduced.The disclosure describes the separation and storage of water vapor, which is later sprayed into the air blown through the spray channel to the cooler by the operation of a water pump. However, the '514 reference does not disclose a cooling system for fuel cells in which liquid hydrogen is heated using evaporators that convert the liquid hydrogen into gaseous hydrogen, which can then be used by hydrogen fuel cells, with the evaporators being integrated into a stacked cooler to enable evaporative cooling, using ambient humidity as the moisture to cool the stacked cooler.

[0006] The system of the present disclosure can solve one or more of the problems listed above and / or other prior art problems. However, the scope of the present disclosure is defined by the attached claims, and not by the ability to solve any specific problem. Brief description

[0007] In one aspect, a system for vaporizing hydrogen to supply gaseous hydrogen to a variety of hydrogen fuel cells comprises: an evaporator; a cooler configured to cool a refrigerant in a cooling system for the various hydrogen fuel cells; a spray supply system comprising: a tank; a pump configured to pump water from the tank; a nozzle system; and a condensate tray configured to collect condensate and return it to the tank. The system is configured to activate the pump to pump the condensate collected in the tank to cool the cooler based on the temperature of the refrigerant.

[0008] In another aspect, a system for cooling the cooler of a hydrogen fuel cell stack comprises: an evaporator; a cooler configured to cool a refrigerant in a cooling system of the hydrogen fuel cell stack; a spray supply system comprising: a tank; a pump configured to pump water from the tank; a nozzle system; and a condensate tray configured to collect condensate and return it to the tank; and a controller, the controller comprising a processor and memory that stores one or more processor-readable instructions. The instructions cause the system to: activate the pump to spray the condensate collected in the tank to cool the cooler based on the temperature of the refrigerant.

[0009] In another aspect, a method for cooling the cooler of a fuel cell stack includes measuring an ambient temperature and determining a temperature difference between the ambient temperature and a stored temperature value; measuring the temperature of a cooling fluid at an outlet of a cooler of the fuel cell stack; and activating a pump to deliver condensate spray through a nozzle system based on the measured temperature exceeding a threshold. The pump is configured to draw liquid collected as condensate from an evaporator, which is designed to vaporize liquid hydrogen to supply hydrogen gas to the fuel cell stack, from a tank. Brief description of the drawings

[0010] The accompanying drawings, which are incorporated into this patent specification and form part of this patent specification, illustrate various exemplary embodiments and, together with the description, serve to explain the principles of the disclosed embodiments. Fig. Figure 1 is a schematic drawing of a system for cooling hydrogen fuel cells according to aspects of this disclosure. Fig. 2 is a control of the system of Fig. 1. Fig. 3A is a first structural partial view of an embodiment of the system of Fig. 1. Fig. 3B is a second structural partial view of the embodiment of the system of Fig. 1. Fig. 4 is a third structural partial view of the in Fig. 3A and Fig. 3B embodiment of the system of Fig. 1, where sections of the embodiment have been removed for clarity. Fig. 5 is a procedure for using the system from Fig. 1-4. Detailed description

[0011] Both the preceding general description and the following detailed description are merely exemplary and explanatory and do not limit the features as claimed. As used herein, the terms "comprises," "comprising," "exhibiting," "including," "comprising," "including," or other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or device comprising a list of elements may include not only those elements but also other elements not expressly listed or inherent to such process, method, article, or device. Unless otherwise specified, relative terms such as "about," "essentially," or "approximately" are used in this disclosure to indicate a possible deviation of ±10% from the stated value.

[0012] With reference to Fig. 1 A system 100 comprises an evaporation circuit 101, which may include a primary evaporator 102, a secondary evaporator 126, a blower mounting plate 104 for mounting at least one blower 106, a blower system 134 for supplying forced air above the secondary evaporator 126, and a cooler 108. The cooler may receive a second fluid from a hydrogen fuel cell cooling system 109 with a fuel cell recirculation 110 and a fuel cell supply 112, the line being equipped with a supply-side temperature sensor 113. System 100 can also include a spray supply system 114, which may comprise several spray nozzles 115, a condensate tray 116 for collecting the condensate condensed by the primary evaporator 102, a water tank 118, which may include an overflow 130, and a water pump 120. A hydrogen supply system 121 can include a liquid hydrogen supply 124 (e.g.,from a liquid hydrogen tank (not shown) that supplies liquid hydrogen to the evaporators for vaporization into a gaseous form. The hydrogen can then flow to a hydrogen gas supply 122 to supply gaseous hydrogen to one or more fuel cells via a gaseous hydrogen supply line 129. The liquid hydrogen supply 124 can supply liquid hydrogen to the evaporator(s) via a hydrogen pump 125 and a liquid hydrogen supply line 127. The hydrogen supply system 121 can include a secondary evaporator hydrogen isolator valve 131 to separate the flow of liquid hydrogen to the secondary evaporator 126 from the liquid hydrogen supply 124. The system 100 can further include a temperature sensor 138 for sensing an ambient temperature.In some embodiments, the evaporators 102, 126 and the cooler 108 can be vertically oriented, and the spray supply system 114 can be configured to spray condensate in an area vertically aligned with one or more of the evaporators 102, 126 and the cooler 108. In some embodiments, the evaporators 102, 126 and the cooler 108 can be connected vertically in series.

[0013] The primary evaporator 102 and the secondary evaporator 126 can be devices that heat and evaporate a working fluid (i.e., liquid hydrogen from the liquid hydrogen supply 124). The primary evaporator 102 and / or the secondary evaporator 126 can have one or more fins 135 and / or one or more guide vanes 136 ( Fig. 3A) for the exchange of heat with the evaporator's surroundings. The evaporators 102, 126 can generally be operated at or near atmospheric pressure. The evaporators 102, 126 can be shell-and-tube heat exchangers or another type of heat exchanger with one or more passes of the working fluid. The evaporators can use the ambient temperature as a heat source or another heat source. In some embodiments, the evaporators 102, 126 can be configured to receive forced air from the blower system 134, thereby increasing the ambient air circulating over the secondary evaporator 126. Both blower systems 106, 134 can be configured to draw air from the cooling chamber 132 and force air over the evaporators 102, 126, drawing cool air along with moisture from the spray supply system 114 over the cooler 108.The humid forced air can cool the cooler 108, which absorbs heat from the hydrogen fuel cell and uses the heat to evaporate the liquid hydrogen in the evaporators 102, 126, as explained in more detail herein.

[0014] With reference to Fig. 2. The system 100 can include a controller 200 that can control the operation of one or more system components. The controller 200 can include a processing device 202 and a memory 204. The controller 200 can receive input data 203, which may include, among other things, pump operating data 206 indicating whether the pump 120 is in an operating state or not, ambient temperature data 208 from the ambient temperature sensor 138, cooler outlet temperature data 210 from the supply-side temperature sensor 113, and fan status data 212 indicating the operating state (e.g., speed) of one or more fans 106 and / or the blowers 134. The controller 200 can generate output data 205, which includes, among other things, a pump control signal 214 for controlling the operation of the pump 120 (e.g., on, off, or flow rate) and an error signal 216, which corresponds to an error condition of the pump 120.

[0015] The controller 200 can be an electronic control module (ECM) and can be communicatively coupled to, or otherwise include, one or more modules or systems for executing one or more functions of the system 100 based on the input data 203. The controller 200 can include a single processor or multiple processors configured to receive inputs, display outputs, and generate instructions to control the operation of the components of the system 100.

[0016] The memory 204 may comprise main memory, a secondary storage device, network interfaces, or any other means for performing tasks consistent with this disclosure. The memory or secondary storage device associated with the controller 200 may store data and software to enable the controller 200 to perform its functions, including those described below. For example, the memory 204 may store one or more predefined values ​​against which an ambient temperature can be compared when one or more functions of the system are performed, as further described herein.One or more of the devices or systems that are communicatively coupled with the controller 200 can be communicatively coupled via a wired or wireless network, such as the Internet, a Local Area Network, WiFi, Bluetooth or any combination of suitable network arrangements and protocols.

[0017] Fig. 3A, Fig. 3B and Fig. 4 represent an exemplary structural configuration of the system of Fig. 1. In some embodiments, the system may comprise 100 walls surrounding the various components, but in the system 100 in Fig. 3A, Fig. 3B and Fig. 4. The walls were removed for better visibility. Additionally, in the Fig. In the embodiment shown in Figure 3A, the condensate tray 116 is located below the radiator 108 and not below the secondary condenser 126. As in Fig. As best illustrated in Figure 3B, the hydrogen supply system 121 can include the liquid hydrogen supply 124, which can provide liquid hydrogen to the evaporator via a hydrogen pump 125 and the liquid hydrogen supply line 127. The liquid hydrogen can be vaporized in the primary evaporator 102 and, in versions that include a secondary evaporator, in the secondary evaporator 126. The vaporized hydrogen can then be supplied to the hydrogen fuel cells via the hydrogen gas supply line 129 and the hydrogen gas supply 122.

[0018] To vaporize the hydrogen in the evaporators 102 and 126 using the evaporation circuit 101, the system 100 can utilize the heat from the ambient air by convection. As shown in Fig. As best illustrated in Figure 3A, the system comprises the blowers 106 (which may be mounted in the blower mounting plate 104), the blowers drawing ambient air 152 from the environment through the primary evaporator 102 and the secondary evaporator 126. The blower system 134 may be configured to push air 150 over the secondary evaporator 126 to evaporate the liquid hydrogen in the secondary evaporator 126. Not all embodiments of the system 100 include a secondary evaporator, but in aspects that do include a secondary evaporator, the secondary evaporator may be isolated from the hydrogen supply. For example, some embodiments may include a secondary evaporator liquid hydrogen isolating valve 131 to separate the flow of liquid hydrogen to the evaporator.

[0019] Fig. Figure 4 represents the spray supply system 114 with the spray nozzles 115 and the water tank 118. The spray nozzles 115 can be configured to spray water from the water tank 118 into a space above the secondary evaporator 126 and below the blowers 106, which are located in Fig. 4 are not shown for the sake of clarity. The spray supply system 114 includes the water pump 120 ( Fig. 1), which can be located in the water tank 118. Commercial applicability

[0020] The system 100 of the present disclosure can be used for simultaneous cooling of hydrogen fuel cell cooling fluid and evaporation of liquid hydrogen for supply to a fuel cell (e.g. a proton exchange membrane fuel cell (PEMFC)).

[0021] With returning reference to Fig. 1. The primary evaporator 102 and the secondary evaporator 126 can receive liquid hydrogen from the liquid hydrogen supply 124 via the hydrogen pump 125 and a liquid hydrogen supply line 127 and evaporate the hydrogen to supply gaseous hydrogen to a fuel cell stack (not shown) via the hydrogen gas supply 122 and a hydrogen gas supply line 129. The liquid hydrogen supply 124 can include a tank in which the hydrogen is stored at a suitable temperature and pressure to keep it in a liquid form (e.g., -423 degrees F at 14.7 psi). The hydrogen gas supply 122 can, for example, supply gaseous hydrogen to a fuel cell stack for the operation of a server farm or other system, where this system may generate a heat load requiring cooling by the cooler 108.In some embodiments, the fuel cell stack can power a vehicle (e.g., a large truck). The vaporizers 102, 126 can add heat to the liquid hydrogen, causing the hydrogen to change from a liquid to a gaseous state. In some configurations, the vaporizers 102, 126 can operate at a temperature lower than the ambient temperature due to the evaporation of hydrogen in their tubes, and this temperature can promote the condensation of liquid from the atmosphere. The system 100 can be configured to collect the liquid that condenses on one or more of the vaporizers 102, 126.

[0022] System 100 can collect the liquid condensed by the evaporator in the condensate tray 116. The condensate tray 116 can have any suitable shape and size to collect the condensate produced by the evaporators 102 and 126. In some embodiments, the condensate tray 116 can be a generally rectangular structure surrounding the evaporator 102 and / or the evaporator 126 (i.e., system 100 can have more than one condensate tray 116) and can have one or more areas capable of receiving water at one or more levels. The condensate can condense on the evaporators 102 and 126 and drip by gravity into the condensate tray 116, where it is collected (e.g., as a gravity accumulation) and drains into the tank 118. The condensate tray 116 can be coated with one or more hydrophobic coatings.

[0023] The condensate tray 116 can supply water to the tank 118. The tank 118 can be equipped with a means for supplying water to the spray supply system 114, such as a pump 120. The pump 120 can be of any suitable design (e.g., positive displacement, centrifugal, and axial pumps, etc.) to provide sufficient delivery head to push the condensed water from the tank 118 to the spray supply system 114, and can draw water from the water tank 118 when it is sufficiently full. The spray supply system 114 can have any number of spray nozzles or other outlets for spraying the water into a cooling room 132.The cooling chamber can generally be arranged such that the fluid flowing through the cooling chamber 132 flows over the cooler 108 and cools the fluid flowing through the cooler and ultimately provides an indirect cooling effect for the hydrogen fuel cell stack (not shown).

[0024] The functions of System 100 of Fig. 1-4 will now be discussed with reference to the in Fig. Method 500 is described in Figure 5. Although Method 500 comprises steps 502-514, it is not limited to these steps and may include more or fewer steps without deviating from the scope of the appended claims. In step 502, the system 100 can determine an ambient air temperature based, for example, on the ambient temperature data 208 from the ambient temperature sensor 138. The system can determine an ambient temperature because, in order for spray cooling from the spray supply system 114 to be effective, a certain temperature difference may be required between the air with the spray jet from the spray nozzles 115 and the air without it. If there is no sufficient temperature difference, operating the water pump 120 to spray the forced air over the cooler will not be more efficient and would therefore be undesirable.In step 504, the system determines, based on the temperature received in step 502, whether the ambient temperature is higher than a threshold temperature difference (i.e., a difference between the ambient temperature and a stored temperature value from a range of stored temperature values). In some embodiments, the stored temperature value used to calculate the temperature difference may depend, at least in part, on one or more of the fans 106, 134 (i.e., the speed at which they operate, as determined, for example, by the fan status data 212).This means that when fans 106 and 134 are activated and operating at a certain speed, the temperature difference used to activate or deactivate pump 120 may have a specific threshold. Similarly, when the fans are operating at a different speed, the temperature difference used to activate or deactivate pump 120 may have a different threshold. If the difference between the ambient temperature and the temperature that would be generated by using the spray function is not sufficiently large (i.e., above a threshold temperature difference), the system will either turn off the pump or leave it turned off at step 512 to avoid increasing the overall energy consumption of the system by running the pump and to maintain system efficiency. However, if the ambient temperature difference is sufficient, the system may proceed to maintain a cooler temperature at an outlet (i.e.,on the side of the fuel cell supply 112 in . Fig. 1) to determine the temperature of the cooler 108. This temperature can, for example, be taken from the temperature sensor 113 and received in step 506 as cooler outlet temperature data 210.

[0025] Based on the temperature in step 506, the system can determine whether or not to start the pump based on the determination in step 508. If the radiator outlet temperature in step 508 exceeds a threshold outlet temperature (for example, 60 degrees Celsius), the system can activate pump 120 in step 510. The threshold outlet temperature used in step 508 can be selected from various values ​​stored in memory 204 and can depend on various factors, such as the status of fans 106 and 134, as determined by the fan status data 212. Activating pump 120 can cause the water collected in water tank 118 to be sprayed through the spray supply system 114 via the spray nozzles 115.The spraying can produce a cooling effect in the cooling chamber 132, which cools the cooler 108 and lowers the temperature of the cooling fluid leaving the cooler 108 for the hydrogen fuel cells. This cools the hydrogen fuel cells and increases their efficiency in generating electricity. When the cooler 108 is cooled and the temperature on the fuel cell supply side 112 decreases, the supply temperature can fall below the threshold, and the system can deactivate pump 120 in step 514. In some embodiments, the system can also deactivate pump 120 based on a fault signal.

[0026] In addition, in some embodiments, the system 100 can be configured to determine one or more fault signals (e.g., based on a fault of the pump 120), after receiving which the system 100 can protect the pump 120.

[0027] An additional feature of the system is that the humid air, which is forced over the condenser and heated by it, generally has a temperature difference with the primary evaporator 102. Since the primary evaporator 102 evaporates liquid nitrogen and operates at temperatures significantly below the ambient temperature, the humidity in the air flowing over the condenser and then over the evaporator 126 condenses on the evaporator, causing water droplets to form and drip from the evaporator 126 due to gravity. In the described system, these condensed droplets are collected by the fan mounting plate 104 and / or the condensate tray 116. The fan mounting plate 104 and / or the condensate tray 116 can be fluidically coupled to the water tank 118 and / or to each other to provide the water tank 118 with condensate as a continuously replenishing water supply for the cooling system.In some embodiments, on sufficiently humid days with a sufficient temperature difference between the ambient temperature and the evaporator temperature, the humidity can simply coalesce on the evaporator without water being sprayed through the spray supply system 114, so that the system has an overall excess of water, since the ambient droplets are collected by the fan mounting plate 104 and / or the condensate tray 116 and returned to the water tank 118. In some embodiments, the secondary evaporator 126 can also be configured to supply water to the water tank 118.

[0028] It should now be clear that a system for evaporating a working fluid can collect the liquid condensed from the atmosphere during such evaporation for reuse within the system. The condensed liquid can be collected in a blower mounting plate and / or a condensate tray and returned to the suction of a blower, where it can be used to cool a chiller used to remove heat from a hydrogen fuel cell stack. The temperature of a coolant at a chiller outlet can be monitored to determine the optimal times for activating and deactivating a pump, thereby optimizing the process of cooling the chiller and simultaneously evaporating the working fluid in the evaporator.Such methods can be particularly useful in dry climates with a large temperature difference between the ambient temperature and the temperature of the cooling fluid exiting the cooler. These climates may also have low relative humidity, so spraying condensate can provide a significant cooling effect. The systems and methods described herein can also be advantageous because they reduce the overall power requirement for operating cooling fans at high ambient temperatures and require less water from external sources, as they condense and collect water from the surrounding environment. Furthermore, the systems and methods can allow for a more compact design, since the increased cooling capacity means fewer coolers are needed.

[0029] It is obvious to those skilled in the field that various modifications and variations can be made to the disclosed system without deviating from the scope of the disclosure. Other embodiments of the system will be obvious to those skilled in the field by considering the specification and practical application of the system disclosed herein. The description and examples are intended to be considered merely exemplary, with the actual scope of the disclosure being specified by the following claims and their equivalents. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 4839514 B2

[0005]

Claims

[1] System (100) for vaporizing hydrogen for supplying hydrogen in gaseous form to a plurality of hydrogen fuel cells, comprising: an evaporator; a cooler (108) designed to cool a cooling fluid in a cooling system of the plurality of hydrogen fuel cells; a spray supply system (114), comprising: a tank; a pump designed to pump water out of the tank; a nozzle system; and a condensate tray (116) designed to collect condensate and return the condensate to the tank, wherein the system (100) is set up to activate the pump to pump the condensate collected in the tank in order to cool the cooler (108) based on a temperature of the cooling fluid. [2] System (100) according to claim 1, further comprising a blower, wherein the blower is configured to push air in series over the cooler (108) and the evaporator. [3] System (100) according to claim 2, wherein the evaporator and the cooler (108) are vertically aligned and the spray supply system (114) is configured to spray condensate in an area in a vertical alignment with the evaporator and the cooler (108). [4] System (100) according to claim 3, wherein the condensate is sprayed under the cooler (108) so that the air blown by the fan carries the sprayed condensate over the cooler (108) and cools the cooler (108). [5] System (100) according to claim 1, wherein the evaporator is configured to evaporate liquid hydrogen from a liquid hydrogen tank. [6] System (100) according to claim 5, further comprising a second evaporator configured to evaporate liquid hydrogen from the liquid hydrogen tank. [7] System (100) according to claim 6, wherein the second evaporator is aligned vertically below the evaporator. [8] System (100) according to claim 1, wherein the system (100) is further configured to activate the pump to spray the condensate collected in the tank based on a temperature in an environment. [9] System (100) according to claim 2, wherein the blower is mounted in a blower mounting plate (104) and the blower mounting plate (104) is configured to collect condensate falling from the evaporator and to supply the collected condensate from the evaporator to the condensate tray (116). [10] System (100) according to claim 1, wherein the evaporator further comprises a plurality of guide plates (136) for collecting moisture.

Images