Electrochemical system and temperature control system

Abstract

The invention is based on an electrochemical system with at least one electrochemical unit (12a; 12b) for an electrochemical conversion of a reactant (14a; 14b) with at least one heat dissipation unit (16a; 16b) for dissipating an operational waste heat of the electrochemical unit (12a; 12b). It is proposed that the electrochemical system comprises at least one refrigeration machine (18a; 18b) which is thermally coupled to the heat dissipation unit (16a; 16b).

Description

State of the art

[0001] An electrochemical system with at least one electrochemical unit for electrochemical conversion of a reactant with at least one heat removal unit for removing operational waste heat from the electrochemical unit has already been proposed. Disclosure of the invention

[0002] The invention is based on an electrochemical system with at least one electrochemical unit for an electrochemical conversion of a reactant with at least one heat dissipation unit for dissipating an operational waste heat of the electrochemical unit.

[0003] It is proposed that the electrochemical system comprise at least one refrigeration machine which is thermally coupled to the heat dissipation unit. The electrochemical unit preferably comprises at least one electrochemical cell, preferably at least one high-temperature electrochemical cell. The at least one electrochemical cell can be designed as a fuel cell, in particular as a high-temperature fuel cell, or as an electrolysis cell, in particular as a high-temperature electrolysis cell. For example, the at least one electrochemical cell is designed as a solid oxide fuel cell, as a solid oxide electrolysis cell, as a molten carbonate fuel cell, or as a molten carbonate electrolysis cell. Particularly preferably, the electrochemical unit comprises a plurality of electrochemical cells which are arranged, for example, in at least one stack or a combination of several stacks.The reactant can be a fuel, in particular a methane-, ammonia-, and / or hydrogen-containing fuel, or an electrolysis reactant, for example water. The at least one electrochemical cell is preferably provided to convert the reactant into at least one product, for example carbon dioxide, water, and / or hydrogen. The waste heat can comprise process heat from the electrochemical conversion of the reactant and / or operating heat, which is released by components of the electrochemical unit at an operating temperature that is higher than the environment of the electrochemical unit. The heat dissipation unit preferably comprises at least one fluid line for mass-bound transport of the waste heat, for example a product line for guiding the product, liquid cooling, air cooling, and / or the like.The heat dissipation unit is, for example, thermally and optionally fluidically connected to the at least one electrochemical cell, to a peripheral device of the electrochemical unit, such as a starter heater, an afterburner, a reformer, or the like, to operating electronics, in particular an inverter, of the electrochemical unit, and / or to another heat-dissipating component of the electrochemical unit. The fluid line can be provided for conducting a process fluid of the electrochemical unit and / or for conducting a coolant or refrigerant that is fluidically separated from the process fluids of the electrochemical unit.Process fluids of the electrochemical unit preferably comprise the reactant, the product, a rinsing fluid and / or other fluids intended for direct contact with catalytic surfaces and / or electrodes of the electrochemical unit, in particular the electrochemical cell.

[0004] "Intended" should be understood in particular to mean specifically programmed, designed, and / or equipped. The fact that an object is intended for a specific function should be understood in particular to mean that the object fulfills and / or performs this specific function in at least one application and / or operating state.

[0005] The refrigeration machine can be designed as a compression refrigeration machine or as an absorption refrigeration machine. The refrigeration machine is preferably intended to provide cold externally or to extract heat from an external source. The refrigeration machine preferably comprises at least one refrigeration circuit for circulating a refrigerant. The refrigeration machine is preferably intended to use at least a portion of the waste heat to operate the refrigeration circuit. The electrochemical system particularly preferably comprises a drive unit for converting at least a portion of the waste heat into mechanical, in particular hydraulic and / or pneumatic, work in order to pressurize the refrigerant in the refrigeration circuit, in particular to circulate and / or compress it. Alternatively or additionally, an expeller of the refrigeration machine is thermally coupled to the heat removal unit in order to desorb the refrigerant from a solvent using the waste heat.

[0006] The inventive design advantageously allows additional cooling to be provided through the operation of the electrochemical unit. In particular, the electrochemical system can be operated with advantageously high overall efficiency.

[0007] It is further proposed that the refrigeration machine comprises a drive unit, in particular the one already mentioned, which is thermally coupled to the heat dissipation unit. The drive unit is preferably connected to a compressor of the refrigeration circuit to drive the compressor. The drive unit preferably comprises at least one expansion element for expanding a fluid carrying the waste heat in the fluid line. The expansion element can be designed, for example, as a turbine, as a membrane, as a piston expander, in particular a reciprocating piston expander, screw expander or the like. The expansion element is preferably mechanically connected to the compressor to transmit work. The expansion element can be directly, ieThe compressor can be connected to the compressor gearlessly, in particular rigidly, for example by means of a common rotational axis, a common translational axis, or the like, or by means of a gear unit of the drive unit. The design according to the invention allows the waste heat to be converted into mechanical work in an advantageously simple and effective manner.

[0008] It is further proposed that the drive unit comprise at least one free piston. The free piston is preferably provided for transmitting mechanical work from the expansion element to the compressor. The free piston is preferably rigidly connected to the expansion element. The free piston is preferably rigidly connected to the compressor. The refrigeration circuit preferably comprises at least one compression fluid chamber in which a section, in particular an end section, of the free piston with the compressor is arranged. The electrochemical system preferably comprises at least one expansion fluid chamber in which a section, in particular an end section, of the free piston with the expansion element is arranged. The heat dissipation unit is preferably thermally and optionally fluidically connected to the expansion fluid chamber.The inventive design allows the electrochemical system to be constructed with advantageously few moving parts. In particular, the electrochemical system is advantageously low-wear and advantageously resistant to failure.

[0009] It is further proposed that the heat dissipation unit is fluidically connected to a refrigeration circuit of the refrigeration machine, in particular the one already mentioned. Preferably, the fluid line of the heat dissipation unit, which is in particular different from the product line, is part of the refrigeration circuit. Preferably, the fluid line is fluidically connected to the expansion fluid chamber. The electrochemical unit preferably comprises at least one heat exchanger for feeding the waste heat into the fluid line. The heat exchanger is particularly preferably designed as an evaporator, which is provided for evaporating the refrigerant. The expansion fluid chamber is preferably arranged downstream of the heat exchanger. The compression fluid chamber is preferably arranged upstream of the expansion fluid chamber, in particular upstream of the heat exchanger. The expansion fluid chamber is preferably arranged upstream of a condenser of the refrigeration circuit.The design according to the invention advantageously minimizes the effort required for fluidically separating the expansion fluid chamber and the compression fluid chamber. In particular, it eliminates the need for hermetic sealing of a passage through the expansion fluid chamber and the compression fluid chamber for accommodating the drive unit, in particular the free piston.

[0010] It is further proposed that the electrochemical system comprise an additional heat transfer medium circuit for fluidically separating a refrigeration circuit of the refrigeration machine from the heat dissipation unit. The refrigeration circuit is preferably fluidically separated from the expansion fluid chamber. The expansion fluid chamber is preferably fluidically arranged in the additional heat transfer medium circuit. The fluid line, which is in particular formed separately from the product line, is preferably part of the additional heat transfer medium circuit. The additional heat transfer medium circuit comprises, for example, a fluid conveying unit, in particular a feed pump, for circulating a heat transfer medium, in particular a refrigerant or coolant. The additional heat transfer medium circuit comprises, for example, the heat exchanger, designed in particular as an evaporator, for evaporating the heat transfer medium.The additional heat transfer circuit comprises, for example, at least one condenser for liquefying the heat transfer medium. The additional heat transfer circuit is preferably designed to implement an organic Rankine cycle (ORC), which transfers the waste heat in the form of mechanical work via the drive unit to the compressor. The inventive design advantageously allows the electrochemical system to be flexibly and easily adjusted to different temperature levels.

[0011] It is further proposed that the heat dissipation unit is fluidically connected to a condenser of the refrigeration machine, in particular the one already mentioned. The condenser is preferably designed to release heat to the ambient air. The electrochemical unit preferably comprises a common return to the condenser, which is connected in parallel to the expansion fluid chamber and to the compression fluid chamber. Optionally, the electrochemical unit comprises a mixing chamber, which is arranged between the common return and the expansion fluid chamber or the compression fluid chamber. The common return is provided in particular to supply the refrigerant to the condenser at a medium pressure level and / or temperature level. The medium pressure level and / or temperature level is preferably between a relative high pressure ora relatively high temperature at which the refrigerant is supplied to the expansion element, and a relative low pressure or a relative low temperature at which the refrigerant is supplied to the compressor element. The expansion fluid chamber comprises, for example, at least one opening or nozzle, by means of which it is fluidically connected to or separated from the condenser depending on a position of the expansion element. The compression fluid chamber comprises, for example, a valve, in particular a check valve, a pressure relief valve or the like, by means of which the compression fluid chamber is fluidically connected to or separated from the condenser depending on a pressure within the compression fluid chamber.Alternatively, the condenser comprises at least two fluidically separated fluid guides within the condenser, one of which is arranged downstream of the expansion fluid chamber and one downstream of the compression fluid chamber. Alternatively, the electrochemical system comprises at least two separately formed condensers, one of which is assigned to the refrigeration circuit and one of which is assigned to the heat dissipation unit. The inventive design advantageously allows the electrochemical system to be designed with few components.

[0012] It is further proposed that the electrochemical system comprise at least one self-regulating valve, by means of which the heat dissipation unit is fluidically connected to a drive unit of the refrigeration machine. The self-regulating valve is preferably arranged in or on the expansion fluid chamber. The self-regulating valve is preferably provided for cyclical opening and closing of the expansion fluid chamber. The self-regulating valve is preferably designed as a continuous valve which, for example, adjusts itself to a degree of opening depending on, in particular proportional to, a state parameter of the expansion fluid chamber. The self-regulating valve preferably closes with increasing pressure and / or temperature of the expansion fluid chamber. The self-regulating valve preferably opens with decreasing pressure and / or temperature of the expansion fluid chamber.Particularly preferably, the self-regulating valve comprises a, in particular purely mechanical, actuating element for adjusting the degree of opening of the valve. Alternatively, the self-regulating valve comprises an electronic control circuit for adjusting the degree of opening by means of an actuator. The design according to the invention advantageously allows a simple cyclical operation of the drive unit.

[0013] It is further proposed that the heat dissipation unit comprise at least one product heat exchanger for thermally coupling a product of the electrochemical conversion, in particular the product already mentioned, with the refrigeration machine. The product heat exchanger is preferably identical to the heat exchanger already mentioned. The product heat exchanger is preferably arranged downstream of the at least one electrochemical cell with respect to the product. The product heat exchanger is preferably provided for transferring the process heat to the fluid line, in particular the additional heat transfer circuit. The design according to the invention allows an advantageously large amount of heat to be used to operate the refrigeration machine.

[0014] It is further proposed that the heat dissipation unit comprise at least one exhaust air heat exchanger for thermally coupling cooling air with the refrigeration machine. The heat dissipation unit preferably comprises the exhaust air heat exchanger in addition to or as an alternative to the product heat exchanger. For example, the exhaust air heat exchanger is arranged as a preheater in a return line of the product heat exchanger. The inventive design allows an advantageously large proportion of the waste heat to be utilized.

[0015] Furthermore, a temperature control system, in particular a building air conditioning system and / or a building ventilation system, is proposed, comprising an electrochemical system according to the invention and at least one fluid guide unit for guiding a fluid cooled by the refrigeration machine. The temperature control system preferably comprises an additional, in particular electrically operated, refrigeration machine, which is provided for cooling room air and / or for cooling a fresh air supply. The evaporator of the refrigeration machine is arranged to support the additional refrigeration machine, for example in a return line of an evaporator of the additional refrigeration machine. Due to the configuration according to the invention, an energy requirement of the temperature control system for cooling a building can be covered at least partially by the waste heat.In particular, additional energy consumption, for example from a power grid, for operating the temperature control system can advantageously be kept low.

[0016] The electrochemical system and / or the temperature control system according to the invention should not be limited to the application and embodiment described above. In particular, the electrochemical system and / or the temperature control system according to the invention may have a number of individual elements, components, and units that differs from the number stated herein to fulfill a functionality described herein. Furthermore, in the value ranges specified in this disclosure, values ​​within the stated limits are also to be considered disclosed and can be used arbitrarily. Drawings

[0017] Further advantages will become apparent from the following description of the drawings. The drawings illustrate two exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0018] They show: Fig. 1 a schematic representation of a temperature control system according to the invention and Fig. 2 a schematic representation of an alternative embodiment of a temperature control system according to the invention. Description of the embodiments

[0019] Fig. 1 shows a temperature control system 40a, in particular a building air conditioning and / or ventilation system. The temperature control system 40a comprises an electrochemical system 10a. The electrochemical system 10a comprises at least one refrigeration machine 18a. The temperature control system 40a comprises a fluid guide unit for guiding a fluid cooled by the refrigeration machine 18a, in particular room air, water, or a heat transfer medium of a cooling circuit or refrigeration circuit of the temperature control system 40a coupled to the refrigeration machine 18a.

[0020] The electrochemical system 10a comprises at least one electrochemical unit 12a for electrochemically converting at least one reactant 14a into at least one product 34a. The electrochemical unit 12a is designed, for example, as a fuel cell unit and comprises at least one fuel cell 48a, in particular a solid oxide fuel cell. The at least one fuel cell 48a is designed, for example, to convert a fuel, in particular hydrogen, natural gas, biogas, or the like, as reactant 14a and ambient air into carbon dioxide and / or water as product 34a. The electrochemical unit 12a preferably comprises a plurality of peripheral devices for operating the at least one fuel cell 48a, in particular for pretreating the reactant 14a and / or for posttreating the product 34a.The peripheral devices include, for example, a reformer, an afterburner, conveyor units, a preheater, internal heat exchangers, an inverter for extracting an electrical current produced by the at least one fuel cell 48a, or the like. The at least one fuel cell 48a is preferably arranged together with the peripheral devices in a common housing of the electrochemical unit 12a.

[0021] The electrochemical system 10a comprises at least one heat dissipation unit 16a for dissipating operational waste heat from the electrochemical unit 12a. The heat dissipation unit 16a comprises, for example, a product line for dissipating the product 34a from the at least one fuel cell 48a. The product line is provided, in particular, for dissipating process heat from the electrochemical conversion of the reactant 14a. The product line opens, for example, into a chimney for discharging the product 34a to the environment, or into a filling station or feed station for transferring the product 34a to an external means of transport or storage device. The heat dissipation unit 16a comprises at least one product heat exchanger 32a.

[0022] The product heat exchanger 32a is preferably arranged along the product line downstream of an internal product heat exchanger 32a of the electrochemical unit 12a for preheating the at least one reactant 14a. The product heat exchanger 32a is preferably provided to transfer the waste heat, in particular the process heat, to a heat transfer circuit of the electrochemical system 10a.

[0023] The heat dissipation unit 16a comprises, for example, a cooling system for cooling at least one of the peripheral devices, in particular the inverter and / or one of the conveyor units. The heat dissipation unit 16a comprises at least one exhaust air heat exchanger 36a for thermally coupling cooling air 38a of the cooling system with the heat transfer circuit.

[0024] The refrigeration machine 18a preferably comprises a refrigeration circuit 24a. The refrigeration machine 18a is designed, for example, as a compression refrigeration machine. The refrigeration machine 18a preferably comprises an evaporator 46a in the refrigeration circuit 24a, which is preferably intended to absorb excess heat 54a from a location of the electrochemical system 10a. The excess heat 54a originates, for example, from a room to be cooled, a fresh air supply to the building, and / or from a higher-level additional main refrigeration machine of the temperature control system 40a. The refrigeration machine 18a preferably comprises a condenser 28a in the refrigeration circuit 24a for discharging waste heat 56a to the environment or to an external disposal system.

[0025] The refrigeration machine 18a preferably comprises at least one compressor element 42a in the refrigeration circuit 24a for pressurizing a refrigerant. The refrigeration machine 18a preferably comprises at least one refrigeration circuit expansion element 50a in the refrigeration circuit 24a for expanding the refrigerant.

[0026] The heat transfer circuit with the heat removal unit 16a, in particular with the product heat exchanger 32a and / or the exhaust air heat exchanger 36a, is preferably designed as a subsection of the refrigeration circuit 24a. The heat transfer circuit is preferably fluidically integrated into the refrigeration circuit 24a downstream of the condenser 28a and upstream of the refrigeration circuit expansion element 50a.

[0027] The heat transfer circuit comprises, for example, a fluid conveying unit 52a, in particular a feed pump, for transporting the refrigerant through the heat transfer circuit. The fluid conveying unit 52a is preferably arranged upstream of the heat removal unit 16a, in particular of the product heat exchanger 32a and / or the exhaust air heat exchanger 36a. The product heat exchanger 32a and / or the exhaust air heat exchanger 36a are / is preferably designed as an evaporator for evaporating the refrigerant. The heat transfer circuit preferably comprises a further condenser 58a for condensing the refrigerant. The further condenser 58a of the heat transfer circuit and the condenser 28a are preferably integrated into one another. The further condenser 58a, orthe condenser 28a in its function as a further condenser 58a, is preferably arranged downstream of the heat removal unit 16a, in particular the product heat exchanger 32a and / or the exhaust air heat exchanger 36a.

[0028] The refrigeration machine 18a comprises a drive unit 20a, which is thermally coupled to the heat dissipation unit 16a. The drive unit 20a is preferably provided to drive the compressor element 42a using the waste heat from the electrochemical unit 12a. The drive unit 20a comprises at least one free piston 22a. The heat transfer circuit preferably comprises an expansion element 44a. The expansion element 44a is preferably provided to convert the waste heat supplied to the refrigerant by the heat dissipation unit 16a into mechanical energy. The drive unit 20a, together with the expansion element 44a, preferably forms a reciprocating piston expander. The expansion element 44a is preferably arranged on the free piston 22a and is provided to move the compressor element 42a via the free piston 22a.An expansion fluid chamber of the drive unit 20a, in which the expansion element 44a is arranged, is preferably arranged fluidically between the heat dissipation unit 16a and the further condenser 58a.

[0029] The electrochemical system 10a includes at least one self-regulating valve 30a. The self-regulating valve 30a is preferably arranged on or in the expansion fluid chamber to effect cyclical movement of the expansion element 44a.

[0030] In the Fig. 2 shows a further embodiment of the invention. The following descriptions and the drawings are essentially limited to the differences between the embodiments, whereby with regard to components with the same designation, in particular with regard to components with the same reference numerals, reference is also made to the drawings and / or the description of the other embodiments, in particular to the Fig. 1. To distinguish the embodiments, the letter a is added to the reference numerals of the embodiment in the Fig. 1. In the examples of the Fig. 2, the letter a is replaced by the letter b.

[0031] Fig.2 shows a temperature control system 40b, in particular a building air conditioning system. The temperature control system 40b comprises an electrochemical system 10b. The electrochemical system 10b comprises at least one electrochemical unit 12b for electrochemically converting a reactant 14b into a product 34b. The electrochemical system 10b comprises at least one heat dissipation unit 16b for dissipating operational waste heat from the electrochemical unit 12b. The electrochemical system 10b comprises at least one refrigeration machine 18b, which is thermally coupled to the heat dissipation unit 16b. The electrochemical system 10b preferably comprises a drive unit 20b for driving the refrigeration machine 18b, in particular a compressor element 42b of the refrigeration machine 18b.

[0032] The electrochemical system 10b comprises an additional heat transfer medium circuit 26b for fluidically separating a refrigeration circuit 24b of the refrigeration machine 18b from the heat dissipation unit 16b. The additional heat transfer medium circuit 26b comprises, for example, the heat dissipation unit 16b, an expansion element 44b arranged on the drive unit 20b, a further condenser 58b and / or a fluid conveying unit 52b, in particular in this order along an intended flow direction of a heat transfer medium within the additional heat transfer medium circuit 26b. The refrigeration circuit 24b comprises, for example, the compressor element 42b, a condenser 28b, a refrigeration circuit expansion element 50b and an evaporator 46b, in particular in this order along an intended flow direction of a refrigerant within the refrigeration circuit 24b. The condenser 28b and the further condenser 58b are preferably integrated into one another.

Claims

[1] Electrochemical system with at least one electrochemical unit (12a; 12b) for an electrochemical conversion of a reactant (14a; 14b) with at least one heat dissipation unit (16a; 16b) for dissipating an operational waste heat of the electrochemical unit (12a; 12b) characterized by at least one refrigeration machine (18a; 18b) which is thermally coupled to the heat dissipation unit (16a; 16b). [2] Electrochemical system according to claim 1, characterized by that the refrigeration machine (18a; 18b) comprises a drive unit (20a; 20b) which is thermally coupled to the heat dissipation unit (16a; 16b). [3] Electrochemical system according to claim 2, characterized by that the drive unit (20a; 20b) comprises at least one free piston (22a; 22b). [4] Electrochemical system according to one of the preceding claims, characterized bythat the heat dissipation unit (16a; 16b) is fluidically connected to a refrigeration circuit (24a; 24b) of the refrigeration machine (18a; 18b). [5] Electrochemical system according to one of claims 1 to 3, characterized by an additional heat transfer circuit (26b) for fluidically separating a refrigeration circuit (24b) of the refrigeration machine (18b) from the heat dissipation unit (16b). [6] Electrochemical system according to one of the preceding claims, characterized by that the heat dissipation unit (16a; 16b) is fluidically connected to a condenser (28a; 28b) of the refrigeration machine (18a; 18b). [7] Electrochemical system according to one of the preceding claims, characterized by at least one self-regulating valve (30a; 30b) by means of which the heat dissipation unit (16a; 16b) is fluidically connected to a drive unit (20a; 20b) of the refrigeration machine (18a; 18b). [8] Electrochemical system according to one of the preceding claims, characterized by that the heat dissipation unit (16a; 16b) comprises at least one product heat exchanger (32a; 32b) for thermally coupling a product (34a; 34b) of the electrochemical conversion with the refrigeration machine (18a; 18b). [9] Electrochemical system according to one of the preceding claims, characterized by that the heat dissipation unit (16a; 16b) comprises at least one exhaust air heat exchanger (36a; 36b) for thermally coupling cooling air (38a; 38b) with the refrigeration machine (18a; 18b). [10] Temperature control system, in particular a building air conditioning system, with an electrochemical system according to one of the preceding claims and with at least one fluid guide unit for guiding a fluid cooled by the refrigeration machine (18a; 18b).

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