Cooling circulation device and cooling system

Abstract

The invention discloses a cooling circulation device and a cooling system, the cooling circulation device comprises a water outlet distribution device, the water outlet distribution device is internally provided with at least two fluid circulation cavities which are isolated from each other, and each fluid circulation cavity is correspondingly communicated with a plurality of water inlets and at least one total water outlet; each water pump is provided with a water pump water inlet pipe and a water pump water outlet pipe, the water pump water outlet pipes are communicated with at least two water inlet pipes in parallel, and each water inlet pipe is correspondingly communicated with one water inlet. By arranging the at least two water pumps for parallel operation and combining the fluid circulation cavity design of the water outlet distribution device, the high-flow heat dissipation requirement of high-power equipment on a cooling medium can be effectively met, the high-power cooling function of a single system is realized, and rapid design matching of a high-power fuel cell cooling circulation system can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cooling circulation systems, in particular to a cooling circulation device and a cooling system. BACKGROUND

[0002] Generally, a liquid-cooled fuel cell uses a water pump to drive the cooling liquid to flow in the fuel cell stack to take away the heat generated by the fuel cell power generation. According to the size of the fuel cell power, the flow rate and head requirement of the cooling medium are different. Large power fuel cells require a larger cooling flow rate, and the flow rate of the fuel cell water pump needs to be developed separately to meet the flow rate required for heat dissipation of large power fuel cells.

[0003] To reduce development cost and shorten development cycle, in a large power fuel cell system, multiple fuel cell water pumps are usually used to meet the heat dissipation requirement. At the same time, in order to guarantee the cold start function, a three-way valve is usually configured in the cooling system of the fuel cell to control the flow direction of the cooling liquid, and a PTC heater is provided for heating the cooling medium in a low temperature environment. The existing scheme generally uses one water pump, one three-way valve and one PTC heater for each fuel cell module. Due to the large flow rate requirement, the pressure drop and flow rate requirement of the three-way valve and the heater are significantly improved, resulting in a more complex selection process. When the power requirement increases, two or more sets of fuel cell modules are used in parallel, and correspondingly, each set of fuel cell module is equipped with a separate water pump, three-way valve and heater liquid cooling circulation system. Or two or more water pumps are used in parallel to meet the liquid cooling heat dissipation requirement of the fuel cell.

[0004] The existing technology is difficult to realize in a large power single fuel cell system; the working conditions of multiple water pump inlets and outlets are difficult to achieve synchronization and consistency, and the outlet pressure of the pipeline is prone to fluctuation, the flow rate is not easy to control accurately, and the control requirement of the water pump is high; the application of multiple components also leads to complex cooling pipelines of the system, difficult manufacturing, high cost; the water flow distribution is difficult to ensure balance in each branch, the pressure drop is high, and the cooling system efficiency is low; when the cooling liquid flow rate is large, the PTC heater is difficult to match, the split type components occupy a large space, and cannot meet the requirements of compact system structure and multiple environmental adaptability. SUMMARY

[0005] Therefore, the present application provides a cooling circulation device and a cooling system to solve the problems of complex control of multiple water pumps, difficult accurate control of flow rate, high pipeline pressure drop and non-compact structure in the prior art.

[0006] In a first aspect, the present application provides a cooling circulation device, comprising:

[0007] The water outlet distribution device has at least two fluid circulation cavities inside and each fluid circulation cavity is correspondingly connected with multiple water inlets and at least one total water outlet;

[0008] At least two water pumps have water pump inlet pipes and water pump outlet pipes, and the water pump outlet pipes are connected with the at least two water inlets in parallel, and each water inlet is correspondingly connected with one water inlet.

[0009] The cooling circulation device has the advantages that: by arranging at least two water pumps to operate in parallel and combining the fluid circulation cavity design of the water outlet distribution device, the large flow cooling medium demand of the high-power equipment can be effectively met, the high-power cooling function of a single system can be realized, and the rapid design matching of the high-power fuel cell cooling circulation system can be realized.

[0010] The fluid circulation cavity of the water outlet distribution device is correspondingly connected with the water inlets of the water pump outlet pipes through multiple water inlets, which can balance the pressure and flow conditions of the multiple water pump inlets and outlets, reduce the outlet pressure fluctuation of the pipeline, reduce the control precision requirement of the water pump, and facilitate the synchronous control of the multiple water pumps.

[0011] The integrated water outlet distribution device integrates multiple water inlets and total water outlets, reduces the number and connection nodes of the external cooling pipelines, avoids the pipeline complexity problem caused by the scattered arrangement of multiple components, and reduces the system manufacturing difficulty and cost.

[0012] The design of the fluid circulation cavity can uniformly mix and distribute the entering cooling liquid in the cavity, balance the water flow of each branch, reduce the system pressure drop, reduce the energy loss, and thus improve the operation efficiency of the cooling system.

[0013] By the integrated layout of the water outlet distribution device and the multiple water pumps, the occupied space of the split components is reduced, the cooling circulation device structure is more compact, and the cooling circulation device is more suitable for different installation environments and various working condition requirements.

[0014] In an optional embodiment, the fluid circulation cavity includes a small circulation cavity and a large circulation cavity, the water inlets include multiple small circulation water inlets connected with the small circulation cavity and multiple large circulation water inlets connected with the large circulation cavity, and the total water outlets include a small circulation total water outlet connected with the small circulation cavity and a large circulation total water outlet connected with the large circulation cavity.

[0015] In an optional embodiment, the water pump outlet pipes are connected with two water inlets in parallel through a three-way valve, the three-way valve has a three-way valve inlet, a three-way valve small circulation outlet and a three-way valve large circulation outlet, the three-way valve small circulation outlet is connected with the small circulation inlet, and the three-way valve large circulation outlet is connected with the large circulation inlet.

[0016] The beneficial effects of the above technical solutions are that the small circulation cavity and the large circulation cavity are integrated in the same water outlet distribution device, replacing the traditional multiple module independent pipeline, reducing the number of external pipelines and connection nodes; at the same time, the structure design of multiple water inlet ports-single total water outlet port shortens the water flow path, reduces the leakage risk caused by complex pipeline, and improves the system reliability. The water outlet distribution device box of the water outlet distribution device is composed of a small circulation cavity and a large circulation cavity, and the flow and pressure of the fluid are stably controlled in the cavity.

[0017] In an optional embodiment, at least one of the fluid circulation cavities is provided with an opening, and the opening is sealed and connected by a heater to form a sealed cavity.

[0018] The beneficial effects of the above technical solutions are that the heater is directly and sealingly connected with the opening of the fluid circulation cavity, replacing the traditional split type heater connected with the circulation system through a pipeline, reducing the additional pipeline interface and sealing link, reducing the risk of cooling liquid leakage from the structure, and improving the reliability of the system operation. The heater and the fluid circulation cavity form a sealed cavity, so that the heating element directly contacts the cooling liquid in the cavity, the heat transfer path is shorter, the heat loss is smaller, the cooling liquid temperature can be quickly raised, especially in the low temperature cold start scene, the start-up time of the fuel cell system can be shortened, and the cold start performance demand can be met. The heater and the fluid circulation cavity are integrated, without the need for independent installation space and connection pipeline of the heater, reducing the dispersion of system components, and making the overall structure of the cooling circulation device more compact.

[0019] In an optional embodiment, the heater includes a plate body and a plurality of heating fins, the plate body blocks the opening, and the heating fins extend into the fluid circulation cavity.

[0020] In an optional embodiment, it further includes a water inlet distribution device, the water inlet distribution device has a water inlet cavity, at least one water inlet port and a plurality of water outlet ports, and the water outlet ports are connected one by one with the water pump inlet pipes.

[0021] In an optional embodiment, the water inlet distribution device and the water outlet distribution device are integrally integrated.

[0022] In an optional embodiment, it further includes an integrated circuit distribution device configured to supply power and / or control the overall device, and the integrated circuit is integrally integrated with the water outlet distribution device.

[0023] In a second aspect, the application provides a cooling system, comprising the cooling circulation device and a device to be cooled, the total water outlet port of the cooling circulation device is connected with the water inlet port of the device to be cooled, and the water outlet port of the device to be cooled is connected with the water pump inlet port of the cooling circulation device.

[0024] The cooling system has the same advantages as the cooling cycle device, which will not be repeated here.

[0025] In an alternative embodiment, the device to be cooled is a fuel cell stack, and the total outlet of the cooling cycle device comprises a small cycle total outlet connected to the fuel cell stack and a large cycle total outlet connected to a heat sink. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0027] Figure 1 A cooling cycle device component schematic diagram is provided for the invention.

[0028] Figure 2 A cooling cycle device partial structure schematic diagram is provided for the invention.

[0029] Figure 3 A cooling cycle device component schematic diagram is provided for the invention.

[0030] Figure 4 A cooling cycle device outlet distribution device schematic diagram is provided for the invention.

[0031] Figure 5 A cooling cycle device outlet distribution device external interface schematic diagram is provided for the invention.

[0032] Figure 6 A cooling cycle device outlet distribution device internal structure schematic diagram is provided for the invention.

[0033] Figure 7 A cooling cycle device heater structure schematic diagram is provided for the invention.

[0034] Figure 8 A cooling cycle device inlet distribution device structure schematic diagram is provided for the invention.

[0035] Figure 9 A cooling cycle device inlet and outlet distribution device integrated structure schematic diagram is provided for the invention.

[0036] Figure 10 A cooling system system schematic diagram is provided for the invention.

[0037] Description of reference numerals:

[0038] 1. Water outlet distribution device, 1b. Large circulation water inlet, 1c. Small circulation water inlet, 1d. Small circulation water outlet, 1e. Large circulation water outlet, 1f. Small circulation cavity, 1g. Large circulation cavity, 2. Water pump, 3. Three-way valve, 4. Water inlet pipe, 5. Water pump inlet pipe, 6. Water inlet distribution device, 6a. Water inlet distribution device inlet, 6b. Water inlet tank outlet, 6c. Return port, 6d. Water inlet cavity, 7. Circuit distribution device, 8. Heater, 8a. Heater power cord, 8b. Heater control line, 8c. Heating plate. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0040] Specific embodiments of the present invention are described in detail below in conjunction with the cooling system of the first aspect of the present invention and the cooling system of the second aspect of the present invention.

[0041] According to an embodiment of the present invention, a first aspect provides a cooling circulation device, Figures 1 to 9 As shown, it includes a water distribution device 1 and a water pump 2. The water distribution device 1 includes a water tank, which has at least two fluid circulation chambers isolated from each other. Each fluid circulation chamber is connected to multiple water inlets and at least one main water outlet. At least two water pumps 2 are provided, each having a water pump inlet pipe 5 and a water pump outlet pipe 10. The water pump outlet pipe 10 is connected in parallel to at least two water inlet pipes 4, each of which is connected to a corresponding water inlet.

[0042] The above cooling circulation device has the following beneficial effects:

[0043] Meet large flow requirements and adapt to high-power systems: By setting at least two water pumps 2 to operate in parallel and combining the fluid circulation cavity design of the water outlet distribution device 1, it can effectively meet the heat dissipation requirements of high-power equipment (such as high-power fuel cell systems) for large flow of cooling medium, realize the high-power cooling function of a single system, and realize the rapid design and matching of high-power fuel cell cooling circulation systems.

[0044] Balancing multiple water pump conditions, simplifying system control: the fluid circulation cavity of the water outlet distribution device is in communication with the water inlet pipe of the water pump outlet pipe through multiple water inlets, which can balance the pressure and flow conditions of the multiple water pump inlets and outlets, reduce the outlet pressure fluctuation of the pipeline, reduce the control accuracy requirement of the water pump, and facilitate the synchronous control of multiple water pumps.

[0045] Simplify the pipeline structure, reduce the cost and manufacturing difficulty: the integrated water outlet distribution device 1 integrates multiple water inlets and a total water outlet, reduces the number of external cooling pipelines and connection nodes, avoids the complex pipeline problems caused by the dispersed arrangement of multiple components, and reduces the system manufacturing difficulty and cost.

[0046] Optimize water flow distribution and improve cooling efficiency: the design of the fluid circulation cavity ensures uniform mixing and distribution of the incoming cooling liquid in the cavity, balances the water flow of each branch, reduces the system pressure drop, and reduces energy loss, thereby improving the operating efficiency of the cooling system.

[0047] Compact structure, enhanced environmental adaptability: through the integrated layout of the water outlet distribution device and multiple water pumps, the occupied space of the split components is reduced, making the cooling circulation device structure more compact and more easily adaptable to different installation environments and various working conditions.

[0048] In some embodiments, the fluid circulation cavity includes a small circulation cavity 1f and a large circulation cavity 1g, and the small circulation cavity 1f and the large circulation cavity 1g are isolated on the water outlet distribution device box. The water inlets include multiple small circulation water inlets 1c in communication with the small circulation cavity 1f and multiple large circulation water inlets 1b in communication with the large circulation cavity 1g, and the total water outlet includes a small circulation total water outlet in communication with the small circulation cavity 1f and a large circulation total water outlet in communication with the large circulation cavity. The water outlet distribution device 1 is provided with a large circulation water inlet 1b, a small circulation water inlet 1c, a small circulation water outlet 1d and a large circulation water outlet 1e, the small circulation water outlet 1d is in communication with the small circulation cavity 1f, and the large circulation water outlet 1e is in communication with the large circulation cavity 1g.

[0049] In this embodiment, the small circulation cavity 1f and the large circulation cavity 1g are integrated in the same water outlet distribution device 1, replacing the traditional multiple module independent pipeline, reducing the number of external pipelines and connection nodes; at the same time, the structure design of multiple water inlets-single total water outlet shortens the water flow path, reduces the leakage risk caused by complex pipeline, and improves the system reliability. The water outlet distribution device box of the water outlet distribution device 1 is composed of the small circulation cavity 1f and the large circulation cavity 1g, and the fluid is stably controlled in terms of flow and pressure in the cavity (water storage space).

[0050] The water outlet distribution device 1 is provided with small circulation cavities 1f and large circulation cavities 1g which are isolated from each other, and corresponding water inlet and outlet interfaces, which can simplify the pipeline of the system, realize average distribution of multiple branches, reduce the pressure drop of the pipeline, and reduce the control difficulty of multiple water pumps.

[0051] In some embodiments, the water pump outlet pipe is connected in parallel with the two water inlet pipes 4 through a three-way valve 3, the three-way valve has a three-way valve water inlet 3a, a three-way valve small circulation water outlet 3b and a three-way valve large circulation water outlet 3c, the three-way valve small circulation water outlet 3b is connected with the small circulation water inlet 1c, and the three-way valve large circulation water outlet 3c is connected with the large circulation water inlet 1b and integrally formed. The cooling circulation device comprises two or more water pumps 2 and two or more three-way valves 3, the number of the water pumps 2 is consistent with the number of the three-way valves 3, and the number of the small circulation water inlets 1c and the large circulation water inlets 1b is consistent. On the assembly of the water outlet distribution device 1 and the heater 8, the same number of two or more three-way valves and water pumps are installed to jointly form the cooling circulation device with the effects of flow equalization, stable flow and stable pressure. Preferably, the multiple small circulation water inlets 1c and the large circulation water inlets 1d are symmetrically arranged on the two sides of the box body.

[0052] In some embodiments, at least one fluid circulation cavity is provided with an opening, and the opening is sealingly connected with the heater 8 to form a sealed cavity. In this embodiment, the heater 8 is directly sealingly connected with the opening of the fluid circulation cavity, replacing the design of the traditional split-type heater connected with the circulation system through a pipeline, reducing the additional pipeline interface and sealing link, and reducing the risk of cooling liquid leakage from the structure, and improving the reliability of the system operation. The heater 8 and the fluid circulation cavity form a sealed cavity, so that the heating element (such as a PTC heating sheet) directly contacts the cooling liquid in the cavity, the heat transfer path is shorter, the heat loss is smaller, the cooling liquid temperature can be quickly raised, especially in the low-temperature cold start scene, the start-up time of the fuel cell system can be shortened, and the cold start performance demand can be met. The heater 8 and the fluid circulation cavity are integrated, without the need for independent arrangement of the installation space of the heater and the connection pipeline, reducing the dispersion of system components, and making the overall structure of the cooling circulation device more compact.

[0053] The heater 8 comprises a plate body, a heater power line 8a, a heater control line 8b and multiple heating sheets 8c, the plate body blocks the opening, and the PTC heating sheet extends into the fluid circulation cavity. The integration of the heater on the water outlet distribution device can reduce the number of component pipeline connection points and reduce the risk of leakage. The heater can increase or decrease the number of heating sheets according to the power demand.

[0054] In some embodiments, the cooling circulation device further comprises a water inlet distribution device 6, which has a water inlet cavity, at least one water inlet port, and a plurality of water distribution ports corresponding to the water pump inlet pipes 5. The water inlet distribution device 6 receives the cooling liquid through one water inlet port, buffers and mixes the cooling liquid in the water inlet cavity, and then connects the plurality of water distribution ports to the water pump inlet pipes 5 one by one, so as to balance the pressure of each water pump inlet, avoid the flow fluctuation caused by the pressure difference of the inlets in the traditional parallel connection of multiple pumps, reduce the precision requirement of the synchronous control of the water pump rotation speed, and realize the stable output of the flow. The water inlet distribution device 6 integrates the water inlet cavity, the water inlet port, and the water distribution port, replaces the traditional design of the separate water inlet distribution pipeline of the multiple water pumps, reduces the number of external pipelines and the connection nodes, reduces the difficulty of pipeline manufacturing and the complexity of assembly, shortens the water flow path, and improves the simplicity of the system layout.

[0055] The water inlet distribution device 6 and the water outlet distribution device 1 are integrally integrated, the installation gap and the connection pipeline when arranged independently are cancelled, the functions such as the water inlet cavity, the fluid circulation cavity, and the water inlet port / water distribution port are integrated into a single module, the overall volume of the cooling circulation device is significantly reduced, and the cooling circulation device is especially suitable for scenes with strict space requirements.

[0056] In some embodiments, the cooling circulation device further comprises an integrated circuit distribution device 7 configured to supply power and / or control the overall device. The integrated circuit is integrally integrated with the water outlet distribution device 1, can realize unified power supply of high-voltage / low-voltage components and simplify the system wire harness, and can realize integrated control of the cooling circulation system and reduce the system control complexity. The water pump 2 and the heater 8 are powered by the same voltage platform and are centrally powered by the circuit distribution device 7. The circuit distribution device 7 includes a control board and integrates the control of the water pump 2, the heater 8, and the three-way valve 3.

[0057] According to the embodiments of the present application, in a second aspect, a cooling system is provided, as shown in Figure 10 The cooling system comprises a cooling circulation device and a device to be cooled. The total water outlet port of the cooling circulation device is connected to the water inlet port of the device to be cooled, and the water outlet port of the device to be cooled is connected to the water pump inlet port of the cooling circulation device.

[0058] The device to be cooled is a fuel cell stack, and the total water outlet of the cooling circulation device comprises a small circulation total water outlet 1d connected with the fuel cell stack and a large circulation total water outlet 1e connected with the heat dissipation device. The water inlet distribution device 6 has a water inlet distribution device water inlet 6a, two or more water tank outlets 6b and a backflow port 6c. The water inlet distribution device water inlet 6a is one, the water tank outlets 6b are two or more and are symmetrically arranged in correspondence with the number of water pumps 2, and the water tank outlets 6b are connected with the inlets 2a of the water pumps 2 through water pump water inlets 5. The water inlet distribution device water inlet 6a is connected with the water outlet of the fuel cell stack, and the backflow port 6c is connected with the water outlet of the expansion water tank. The inlet working condition of the fluid entering the multiple parallel water pumps is unified in the cavity (water storage space).

[0059] The present application provides a cooling circulation device, which meets the demand of large flow by using multiple water pumps, especially the large flow demand of heat dissipation of a high-power fuel cell system, and ensures the normal work of the fuel cell system.

[0060] The cooling circulation device integrates the components in the cooling system when multiple water pumps are applied. The water distribution device 1 is designed to facilitate the symmetric arrangement of the multiple water pumps 2, the components are arranged reasonably, the pipeline is shorter and smoother, and the number of pipeline opening molds is less. The fluid circulation cavity balances the inlet and outlet pressures of the multiple water pumps, the multiple water pumps can be commanded at the same speed, and the system control is simplified. The layered cavity of the water distribution device 1 and the heater integrated with the small circulation cavity reduce the pipeline and connection points of the small and large circulation systems, reduce the pressure resistance of the water system, and reduce the risk of leakage. The present application designs a circuit distribution device to realize the power function and control integration of each component on the cooling circulation device.

[0061] The modular cooling circulation device further simplifies the cooling path design of the fuel cell system. According to different fuel cell system powers, the universal water pump and the three-way valve are selected, and only the number needs to be increased or decreased to achieve the selection. The heater can select the required heating power by increasing or decreasing the number of heating elements in the heating ribs.

[0062] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A cooling cycle device, characterized in that: include: A water distribution device (1), wherein at least two fluid circulation cavities isolated from each other are provided inside the water distribution device (1), and each of the fluid circulation cavities is connected to and provided with a plurality of water inlets and at least one total water outlet; At least two water pumps (2) are provided, each having a water pump inlet pipe (5) and a water pump outlet pipe (10), wherein the water pump outlet pipe (10) is connected in parallel with at least two water inlet pipes (4), and each of the water inlet pipes (4) is connected to a corresponding water inlet.

2. The cooling cycle device according to claim 1, characterized in that: The fluid circulation cavity comprises a small circulation cavity (1f) and a large circulation cavity (1g); the water inlet comprises a plurality of small circulation water inlets (1c) communicating with the small circulation cavity (1f) and a plurality of large circulation water inlets (1b) communicating with the large circulation cavity (1g); and the total water outlet comprises a small circulation total water outlet communicating with the small circulation cavity (1f) and a large circulation total water outlet communicating with the large circulation cavity.

3. The cooling cycle device according to claim 2, characterized in that: The water pump outlet pipe is connected in parallel with the two water inlet pipes (4) via a three-way valve (3); the three-way valve comprises a three-way valve water inlet, a three-way valve small circulation water outlet, and a three-way valve large circulation water outlet; the three-way valve small circulation water outlet is connected to the small circulation water inlet (1c), and the three-way valve large circulation water outlet is connected to the large circulation water inlet (1b).

4. The cooling cycle device according to claim 1, characterized in that At least one of the fluid circulation cavities is provided with an opening, and the opening is sealed and connected via a heater (8), so that the fluid circulation cavity forms a sealed cavity.

5. The cooling cycle device according to claim 4, characterized in that: The heater (8) comprises a plate body and a plurality of heating plates, the plate body seals the opening, and the heating plates extend into the fluid circulation cavity.

6. The cooling cycle device according to claim 1, characterized in that It also includes a water inlet distribution device (6), which has a water inlet cavity, at least one water inlet and a plurality of water diversion ports, and the water diversion ports are connected to the water pump inlet pipes (5) in a one-to-one correspondence.

7. The cooling cycle device according to claim 6, characterized in that: The water inlet distribution device (6) is integrated with the water outlet distribution device (1).

8. The cooling cycle device according to any one of claims 1 to 7, characterized in that: It also includes an integrated circuit distribution device, which is configured to power and / or control the entire device, and the integrated circuit is integrated with the water distribution device (1).

9. A cooling system, characterized in that: It comprises the cooling circulation device and the equipment to be cooled according to any one of claims 1 to 8, wherein the total water outlet of the cooling circulation device is connected to the water inlet of the equipment to be cooled, and the water outlet of the equipment to be cooled is connected to the water pump inlet of the cooling circulation device.

10. The cooling system according to claim 9, characterized in that The equipment to be cooled is a fuel cell stack, and the total water outlet of the cooling circulation device includes a small circulation total water outlet connected to the fuel cell stack and a large circulation total water outlet connected to the heat dissipation device.

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