High-efficiency integrated absorption cooling system utilizing fuel cell array

Abstract

The absorption cooling system of the present invention comprises a fuel cell unit (100) that discharges exhaust gas generated during power generation and an absorption cooling unit (200) that utilizes the exhaust gas as a heat source. The absorption cooling unit (200) comprises an absorption chiller (10) supplied with the exhaust gas as a heat source; an upper cooling tower (30) that lowers the temperature of the cooling water heated by the absorption chiller; a cooling water pump (40) that controls the flow of the cooling water; a chilled water pump (50) that controls the flow of chilled water cooled by the absorption chiller; a system control unit (90) that controls the drive of the absorption cooling unit (200); a bypass valve (60) installed in a bypass pipe (12) that controls the external discharge of the exhaust gas supplied from the fuel cell unit (100); an exhaust gas introduction valve (70) installed in an exhaust gas introduction pipe (13) that controls the supply of the exhaust gas to the absorption chiller (10); and an exhaust gas fan (suction device) (20) that provides pressure so that the exhaust gas is supplied to the absorption chiller (10).

Description

Technical Field

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[0001] The present invention relates to a dual-purpose absorption refrigeration system that uses relatively low-temperature exhaust gas generated when producing electricity with a fuel cell as a heat source.

[0002] More specifically, the present invention relates to an absorption refrigeration system that supplies the exhaust gas generated by a fuel cell to the regeneration heat exchanger (HTG, high-temperature regenerator) of a highly efficient dual-purpose absorption refrigerator and utilizes it as a heat source.

Background Art

[0003] Worldwide, medium and large-scale power generation fuel cell systems are on the rise. Phosphoric acid type (PAFC) fuel cells and solid oxide type (SOFC) fuel cells are mainly used for power generation. On the other hand, in the case of power generation fuel cell systems of a certain scale or more, an electric refrigerator (such as an air conditioner) is installed to eliminate the heat load of the electric room that produces and converts electricity.

[0004] In the case of a phosphoric acid type (PAFC) fuel cell, an exhaust heat utilization system that produces chilled water using the exhaust heat generated as warm water at a level of about 60 to 90 degrees together with electricity by using a single-effect absorption refrigerator has been developed. However, it has been pointed out that the shortcoming is that the cooling performance coefficient (COP) using exhaust heat is as low as 0.7 level. In addition, problems such as excessive power consumption due to driving the chilled water, cooling water, and warm water pumps for the absorption refrigerator and the generation of white smoke in the cooling tower that is inevitably configured have been pointed out as shortcomings.

[0005] In the case of a solid oxide type (SOFC) fuel cell, exhaust gas at about 300 to 400 degrees is generated as exhaust heat together with electricity. However, since the discharge pressure of such exhaust gas is very low at 10 to 50 mmAq and the exhaust gas temperature is only 300 to 400 degrees, there are limitations in the system cooperation with a highly efficient dual-purpose absorption refrigerator.

[0006] As described above, cooling systems applicable to medium- and large-scale fuel cell power generation systems can be integrated with power generation facilities, and the demand for cooling from data centers, smart farms, and other locations that require both power and cooling loads simultaneously is increasing. However, efficient cooling systems that utilize the waste heat from power generation fuel cells have not yet been developed. [Overview of the project] [Problems that the invention aims to solve]

[0007] To solve the problems described above, the objective of the present invention is to provide a system that uses a double-effect absorption chiller to produce chilled water using exhaust gas at a relatively low temperature (300-390°C) generated when producing electricity with a fuel cell as a heat source.

[0008] More specifically, the system aims to provide an improved overall efficiency for the fuel cell unit by supplying the exhaust gas generated by the solid oxide fuel cell (SOFC) to the highly efficient regenerative heat exchanger (HTG, high-temperature regenerator) of a double-effect absorption chiller, utilizing it as a heat source, recovering the waste heat from the exhaust gas to produce chilled water, which is then used for cooling at the customer's facility.

[0009] Furthermore, to prevent the white smoke phenomenon that occurs in cooling towers when the outside air temperature is low and the relative humidity is high, the system aims to provide a cooling system that prevents white smoke by introducing a portion of the exhaust gas discharged into the atmosphere via a regenerative heat exchanger (HTG, high-temperature regenerator) into a white smoke prevention device. [Means for solving the problem]

[0010] The absorption cooling system of the present invention comprises a fuel cell unit (100) that discharges exhaust gas generated during power generation and an absorption cooling unit (200) that utilizes the exhaust gas as a heat source. The absorption cooling unit (200) includes an absorption chiller (10) supplied with exhaust gas as a heat source; an upper cooling tower (30) that lowers the temperature of the cooling water heated by the absorption chiller; a cooling water pump (40) that controls the flow of the cooling water; a chilled water pump (50) that controls the flow of chilled water cooled by the absorption chiller; a system control unit (90) that controls the drive of the absorption cooling unit (200); a bypass valve (60) installed in a bypass pipe (12) that controls the external discharge of exhaust gas supplied from the fuel cell unit (100); an exhaust gas introduction valve (70) installed in an exhaust gas introduction pipe (13) that controls the supply of exhaust gas to the absorption chiller (10); and an exhaust gas fan (suction device) (20) that provides pressure so that the exhaust gas is supplied to the absorption chiller (10).

[0011] In one embodiment, the absorption chiller (10) is a double-effect absorption chiller equipped with a regenerative heat exchanger (HTG, high-temperature regenerator), the regenerative heat exchanger (HTG, high-temperature regenerator) is equipped with a regenerative exhaust gas pipe (16) through which exhaust gas supplied from a fuel cell unit (100) travels, and the exhaust gas fan (suction device) (20) is installed downstream of the regenerative exhaust gas pipe (16).

[0012] In one embodiment, the system may further include: an exhaust gas discharge pipe (14) for discharging exhaust gas discharged from an exhaust gas fan (suction device) (20) to the outside; a white smoke prevention pipe (15) connected to the exhaust gas discharge pipe (14) for transmitting exhaust gas to an upper cooling tower (30); and a cooling tower inlet valve (80) for controlling the white smoke prevention pipe (15).

[0013] In one embodiment, the system control unit (90) controls the opening and closing rate of the bypass valve (60) in accordance with the cooling drive conditions of the absorption cooling unit (200) in order to maintain the back pressure inside the fuel cell unit (100) within a specified range when the absorption cooling unit (200) is driven to cool.

[0014] In one embodiment, the cooling drive conditions of the absorption cooling unit (200) may include the degree of operation of the exhaust gas fan (suction device) (20), the opening and closing rate of the exhaust gas introduction valve (70), the degree of operation of the cooling water pump (40), and the degree of operation of the chilled water pump (50).

[0015] In one embodiment, when the absorption cooling system is under maximum load (S320), the system control unit (90) opens the exhaust gas inlet valve (70) to its maximum extent, drives the exhaust gas fan (suction device) (20) within a set high-load operating Hz range, and adjusts the opening and closing rate of the bypass valve (60) to maintain the back pressure inside the fuel cell unit (100) within a specified range.

[0016] In one embodiment, when the absorption cooling system is at partial load (S330), the system control unit (90) adjusts the degree of operation of the exhaust gas fan (suction device) (20) according to the cooling load of the absorption chiller (10), and the opening and closing rate of the bypass valve (60) is adjusted to maintain the back pressure inside the fuel cell unit (100) within a specified range.

[0017] In one embodiment, the absorption chiller (10) further includes an exhaust gas inlet temperature sensor (S1); an exhaust gas outlet temperature sensor (S2); and a regenerative heat exchanger temperature sensor (S3). When the absorption chiller (10) is determined to be in an over-concentration state, the bypass valve (60) is fully opened, the exhaust gas introduction valve (70) is fully closed, the exhaust gas fan (suction device) (20) is stopped, and the chilled water outlet current temperature (T_pv) of the absorption chiller (10) is maintained at or above the restart temperature (T_limit_H).

[0018] In one embodiment, the upper cooling tower (30) is equipped with a fan (31), a cooling water spraying device (33) for spraying cooling water, a packing material (34), and a white smoke prevention device (32). The white smoke prevention device (32) is characterized in that, when conditions for the generation of white smoke in the upper cooling tower (30) are detected, exhaust gas is supplied from a white smoke prevention pipe (15) controlled by a cooling tower inlet valve (80) and supplied into the cooling tower (30) to prevent the white smoke phenomenon.

[0019] In one embodiment, the white smoke prevention device (32) is located at the bottom of the upper cooling tower (30) and is characterized by supplying exhaust gas to the packing material (34) from the bottom upward. [Effects of the Invention]

[0020] According to the present invention, exhaust gas at a temperature of 300 to 400 degrees Celsius, discharged from a fuel cell at a relatively low pressure (10 to 50 mmAq), can be utilized as a highly efficient dual-effect absorption cooling heat source. This ultimately provides a fuel cell absorption cooling system capable of highly efficient cooling with a coefficient of performance (COP) of 1.1 to 1.4 or higher.

[0021] Furthermore, when the outside air is cold and humid, white smoke (condensation of moisture in saturated air) is generated in the cooling tower and released into the atmosphere. However, by introducing a portion of the low-temperature (80-150 degrees Celsius) exhaust gas emitted from the fuel cell and used as a cooling heat source for the high-efficiency dual-effect absorption chiller into the atmosphere into the cooling tower white smoke prevention device, white smoke can be prevented, thus preventing the freezing of surrounding facilities that may be caused by white smoke in winter. [Brief explanation of the drawing]

[0022] [Figure 1] Figure 1 is a diagram illustrating the configuration of a highly efficient integrated absorption cooling system utilizing a fuel cell array according to the present invention. [Figure 2] Figure 2 is a diagram showing a part of the absorption cooling system according to the embodiment of Figure 1. [Figure 3a] Figures 3a to 3c are flowcharts showing the operation of the absorption cooling system according to the embodiment of Figure 1. [Figure 3b] Figures 3a to 3c are flowcharts showing the operation of the absorption refrigeration system according to the embodiment of FIG. 1. [Figure 3c] Figures 3a to 3c are flowcharts showing the operation of the absorption refrigeration system according to the embodiment of FIG. 1. [Figure 4a] Figure 4a is a configuration diagram showing the cooling tower of the absorption refrigeration system according to the embodiment of FIG. 1. [Figure 4b] Figure 4b is a configuration diagram showing the cooling tower of the absorption refrigeration system according to another embodiment of the present invention.

Mode for Carrying Out the Invention

[0023] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. In this process, the thickness of the lines and the size of the components illustrated in the drawings may be exaggerated for clarity and convenience of explanation. Also, the terms described later are terms defined in consideration of the functions in the present invention, and these may vary depending on the intention or convention of the user or operator. Therefore, the definition of such terms should be made based on the content throughout this specification.

[0024] As used herein, a module can mean a functional and structural combination of hardware for implementing the technical idea of the present invention and software for driving the hardware. For example, the module can mean a logical unit of a predetermined code and the hardware resources for executing the predetermined code, and it can be easily inferred by an average expert in the technical field of the present invention that it does not necessarily mean physically connected code or a certain type of hardware.

[0025] Furthermore, when a component is described as being "connected" to or "connected" to another component, it should be understood that it may be directly connected to or connected to the other component, or that other components may exist in between. On the other hand, when a component is described as being "directly connected" to or "directly connected" to another component, it should be understood that there are no other components in between.

[0026] Unless the context clearly indicates otherwise, singular expressions include plural expressions. Furthermore, throughout this specification, when a part "includes" a component, this does not exclude other components unless specifically contradicted, but rather means that other components may be further included. It will be obvious to those skilled in the art that the present invention can be embodied in other specific forms without departing from its essential features.

[0027] Furthermore, the following embodiments are not intended to limit the scope of the present invention but are merely illustrative examples, and a variety of embodiments may be realized through this technical concept. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same elements.

[0028] Air conditioning system configuration

[0029] Figure 1 is a diagram illustrating the configuration of a highly efficient integrated absorption cooling system utilizing a fuel cell array according to the present invention.

[0030] Referring to Figure 1, the fuel cell array-based high-efficiency integrated absorption cooling system (1000) comprises a fuel cell unit (100) and an absorption cooling unit (200).

[0031] The fuel cell unit (100) uses a solid oxide (SOFC) fuel cell, and its primary purpose is to produce electricity, but at the same time as generating electricity, it generates exhaust gas at approximately 300-400 degrees Celsius. The absorption cooling unit (200) utilizes the exhaust gas emitted by such a fuel cell for cooling. Because the exhaust gas emitted by the fuel cell does not reach the permissible range for normal operation in terms of temperature and pressure compared to the heat source used in existing absorption chillers, additional equipment is required compared to existing absorption chillers.

[0032] The absorption cooling unit (200) comprises an absorption chiller (10), an exhaust gas fan (suction device) (20), and an upper cooling tower (30), and further includes a cooling water pump (40), a chilled water pump (50), a bypass valve (60), an exhaust gas inlet valve (70), a cooling tower inlet valve (80), and a system control unit (90).

[0033] The absorption chiller (10) can be a double-effect high-efficiency absorption chiller. In addition to the absorption chiller (10), the system includes a cooling water pump (40) that supplies cooling water applicable to a typical absorption chiller (10), a chilled water pump (50) that brings in and discharges chilled water, an upper cooling tower (30) that cools the cooling water, and a system control unit (90) that drives / controls various pumps, valves, and devices.

[0034] In particular, an exhaust gas fan (suction device) (20) is included to draw in the exhaust gas generated by the fuel cell and apply it to the absorption chiller (10). A bypass valve (60) and an exhaust gas inlet valve (70) are also installed to control the incoming exhaust gas. The bypass valve (60) and the exhaust gas inlet valve (70) can be configured as a single three-way valve.

[0035] The exhaust gas fan (suction device) (20) is installed downstream of the regenerator exhaust gas pipe (16), which will be described later, and adjusts the exhaust gas suction pressure to provide the pressure at which the exhaust gas is supplied to the absorption chiller (10), as well as the pressure at which it is discharged to the outside and the pressure supplied to the cooling tower (30) to prevent white smoke.

[0036] The exhaust gas at approximately 300-400 degrees Celsius generated simultaneously with electricity production by the fuel cell unit (100) is supplied to the regenerative heat exchanger (HTG, high-temperature regenerator) of the absorption chiller (10) through the exhaust gas introduction pipe (11). The supplied exhaust gas can be discharged to the outside through the bypass pipe (12) controlled by the bypass valve (60), and at the same time, it is supplied to the absorption chiller (10) through the exhaust gas introduction pipe (13) controlled by the exhaust gas introduction valve (70). If the absorption chiller (10) is a double-effect high-efficiency absorption chiller, the exhaust gas is supplied to the regenerative heat exchanger (HTG, high-temperature regenerator), and the exhaust gas heat can be transferred to the regenerative heat exchanger (HTG, high-temperature regenerator) through the regenerative heat exchanger exhaust gas pipe (16) inside the regenerative heat exchanger.

[0037] At this time, an exhaust gas fan (suction device) (20) is provided to control the back pressure of the exhaust gas supplied to the absorption chiller (10), and the exhaust gas fan (suction device) (20) is discharged to the outside through the exhaust gas discharge piping (14). The exhaust gas discharge piping (14) is supplied to the white smoke prevention device (32) of the upper cooling tower (30) for white smoke prevention through white smoke prevention piping (15) controlled by the cooling tower inlet valve (80).

[0038] The cooling water pump (40), chilled water pump (50), bypass valve (60), exhaust gas inlet valve (70), cooling tower inlet valve (80), exhaust gas fan (suction device) (20), and cooling fan (31) are all controlled by the control unit (90).

[0039] As mentioned above, the back pressure of exhaust gas generated by a typical fuel cell is at a very low level of 10-50 mmAq and is not naturally supplied to the absorption chiller. However, the exhaust gas fan (suction device) (20), a feature of the present invention, can apply the exhaust gas to the absorption chiller, and the exhaust gas fan (suction device) (20) induces the optimal amount of exhaust gas input through rotational speed control.

[0040] Maintaining the back pressure of the fuel cell is crucial because excessive exhaust gas suction pressure from the exhaust gas fan can cause a drop in the fuel cell stack pressure, potentially reducing power generation efficiency (G_normal).

[0041] The exhaust gas flow rate is determined by the fuel cell's power generation load, but this does not match the airflow rate required by the absorption chiller. Therefore, the absorption chiller reads the set target chilled water outlet temperature and the current chilled water inlet / outlet temperatures to sense the cooling load and controls the amount of exhaust gas introduced accordingly.

[0042] The optimal exhaust gas input amount applied at this time can be achieved by the system control unit (90) through inverter control, sensing the required cooling load and the power generation load of the fuel cell unit (100). The control means utilize inverter rotation speed control of the exhaust gas fan (suction device) (20), an exhaust gas bypass valve (60), and an exhaust gas introduction valve (70).

[0043] Cooling system operation

[0044] Figure 2 is a configuration diagram showing a part of the absorption cooling system according to the embodiment in Figure 1. Figures 3a to 3b are flowcharts showing the operation of the absorption cooling system according to the embodiment in Figure 1.

[0045] Referring first to Figures 3a to 3c, the operation of the absorption cooling system according to this embodiment includes a cooling stop step (S100) in which the fuel cell unit (100) is driven but the absorption cooling unit (200) is not yet driven, a cooling start step (S200) in which the absorption cooling unit (200) starts up for the first time, a cooling operation step (S300) in which the absorption cooling unit (200) performs cooling operation according to the exhaust gas condition and the required cooling load, a forced stop step (S400) in which the operation is stopped according to conditions set to protect the equipment, and a cooling end step (S500) in which the cooling is terminated.

[0046] First, the cooling shutdown step (S100) is a step in which the absorption cooling unit (200) is not driven. In this step, all bypass valves (60) are opened and all exhaust gas inlet valves (70) are closed so that exhaust gas is not used for cooling drive. Also, the exhaust gas fan (suction device) (20) is kept stopped. All exhaust gas generated by the fuel cell unit (100) is discharged to the outside.

[0047] In the cooling start step (S200), the absorption chiller (10) of the absorption cooling unit (200) is started. In the cooling start step of this embodiment, the exhaust gas introduction valve (70) is opened to its maximum extent, and the exhaust gas fan (suction device) (20) is driven at maximum load.

[0048] In the cooling operation step (S300), the operation is controlled in different ways depending on the operating environment. This is due to the characteristic of controlling the operation of the absorption chiller using the exhaust gas of the fuel cell. The specific steps are as follows, and this depends on the driving conditions, and does not mean that each step should proceed sequentially.

[0049] The bypass valve control operation step (S310) controls the current back pressure (P1_pv) to satisfy the required back pressure target value (P1_cv), and this should proceed while maintaining the normal power generation efficiency (G_normal) of the fuel cell unit (100). Therefore, the opening and closing rate of the bypass valve (60) is adjusted in accordance with other driving conditions in order to adjust the required back pressure current value (P1_pv). The first constraint on which the absorption cooling unit (200) should be driven is that it should not affect the power production of the fuel cell unit (100). Since excessive intake of exhaust gas may affect power production, a function to adjust the bypass valve (60) so that the current back pressure (P1_pv) reaches the back pressure target value (P1_cv) is added as an essential measure to prevent this. The bypass valve control operation step (S310) proceeds in parallel with the driving of the following three operation steps.

[0050] In the maximum load operation step (S320), the operation proceeds on the condition that the current chilled water outlet temperature (T_pv) is greater than the chilled water target temperature (T_cv) to which the high load judgment band (T_band_H) is applied. The rated output of the fuel cell should be maintained, and the system is driven under conditions that maximize the cooling load. At this time, the exhaust gas inlet valve (70) is opened to its maximum extent (S321), the bypass valve (60) is closed to almost zero, and the exhaust gas fan (suction device) (20) is driven at the maximum allowable value within the set high load operation Hz range (S322). At this time as well, the fuel cell power generation efficiency (G_normal) and the current back pressure value (P1_pv) are sensed and adjusted, and rated cooling operation is performed.

[0051] The partial load operation step (S330) occurs when the fuel cell unit (100) is operated at rated load, but the cooling load is at partial load. This applies when the current chilled water outlet temperature (T_pv) is lower than the chilled water target temperature (T_cv) to which the high load determination band (T_band_H) is applied, but higher than the chilled water target temperature (T_cv) to which the low load determination band (T_band_L) is applied. In this case, the absorption chiller (10) reads the cooling load and adjusts the exhaust gas volume. The output of the exhaust gas fan (suction device) (20) is adjusted preferentially, and the bypass valve (60) is adjusted based on the fuel cell's power generation efficiency (G_normal) and exhaust gas pressure (P1_pv) to minimize the cooling load adjustment and the power consumption of the exhaust gas fan (suction device) (20).

[0052] The minimum load operation step (S340) is when the cooling load is operated at the minimum load. In this case, the exhaust gas fan (suction device) (20) is stopped or driven at the minimum Hz, and the minimum load is maintained through the control of the exhaust gas inlet valve (70).

[0053] The forced stop step (S400) is a step to prevent overconcentration of the absorption chiller. This occurs when the current chilled water outlet temperature (T_pv) falls below the stop temperature (T_limit_L) (S410). The absorption chiller regenerative heat exchanger temperature sensor (S3) and exhaust gas temperature sensors (S1, S2) detect the overconcentration state of the absorption chiller. At this time, overconcentration may occur, so the chiller is forcibly stopped (S420). The bypass valve (60) is fully opened, the exhaust gas inlet valve (70) is closed, and the exhaust gas fan (suction device) (20) is stopped. In some cases, the exhaust gas inlet valve (70) can be emergency closed to protect the equipment if the concentration exceeds the standard value. The forced stop state is maintained until the current chilled water outlet temperature (T_pv) rises above the restart temperature (T_limit_H) (S430).

[0054] The cooling termination step (S500) is the step in which the cooling is terminated, and the driving conditions are the same as those for the cooling stop step (S100). In this step, all bypass valves (60) are opened and all exhaust gas inlet valves (70) are closed so that exhaust gas is not used for cooling drive. Also, the exhaust gas fan (suction device) (20) is kept stopped. All exhaust gas generated by the fuel cell unit (100) is discharged to the outside.

[0055] White smoke prevention function

[0056] Figure 4a is a diagram showing the cooling tower of the absorption cooling system according to the embodiment of Figure 1.

[0057] Referring to Figure 4a, the upper cooling tower (30) of the absorption cooling system in this embodiment is equipped with a white smoke prevention device (32) to prevent white smoke from being generated when the outside air is cold and humid. The upper cooling tower (30) of this embodiment is equipped with a packing material (34), a cooling water spraying device (33), and a cooling tower fan (31), which are typical cooling tower configurations, and in addition, it is further equipped with a white smoke prevention device (32) that utilizes exhaust gas and a cooling tower inlet valve (80).

[0058] The upper cooling tower (30) is responsible for lowering the cooling water temperature by releasing the heated cooling water of the absorption chiller, which is operated when a cooling load is generated, into the atmosphere. When the conditions for white smoke generation in the upper cooling tower (30) are detected, the white smoke prevention device (32) automatically directs a portion of the exhaust gas generated by the fuel cell, supplied to the absorption chiller, and discharged at approximately 80-150 degrees Celsius, into the white smoke prevention device (32) through the cooling tower inlet valve (80). The introduced portion of the exhaust gas flows in along the coil inside the white smoke prevention device (32) or along the numerous open holes on top of the coil, and exchanges heat with or mixes with saturated air as it passes through the packing material (34). This raises the temperature of the saturated air and lowers its relative humidity, thus preventing the white smoke phenomenon.

[0059] Figure 4b is a diagram showing a cooling tower for an absorption cooling system according to another embodiment of the present invention.

[0060] Referring to Figure 4b, the white smoke prevention device (32) is installed at the bottom of the upper cooling tower (30) with the coil positioned toward the packing material (34). As saturated air passes through the packing material (34) and then through the white smoke prevention coil (35), it heats up and its relative humidity decreases, thus preventing the white smoke phenomenon. Additionally, a hole is formed at the top of the coil, allowing exhaust gas to be discharged to the top of the coil and finally mixed with the heated air, further preventing white smoke.

[0061] Furthermore, in Figures 4a and 4b, the inlet valve (80) can adjust the exhaust gas volume when white smoke is generated, and an additional drain pipe (not shown) is installed to discharge exhaust gas condensate to the outside when it is generated inside the coil.

[0062] Although the embodiments have been described above with limited drawings, a person with ordinary skill in the relevant art can apply a variety of technical modifications and variations based on the above. For example, the described techniques may be performed in a different order than described, and / or the components of the described systems, structures, devices, circuits, etc. may be combined or assembled in a different manner than described, or substituted or replaced by other components or equivalents, and the appropriate results may still be achieved. Accordingly, other implementations, other embodiments, and equivalents to the claims described below also fall within the scope of the claims. [Industrial applicability]

[0063] According to the present invention, exhaust gas at a temperature of 300 to 400 degrees Celsius, discharged from a fuel cell at a relatively low pressure (10 to 50 mmAq), can be utilized as a highly efficient dual-effect absorption cooling heat source. This ultimately provides a fuel cell absorption cooling system capable of highly efficient cooling with a coefficient of performance (COP) of 1.1 to 1.4 or higher.

[0064] Furthermore, when the outside air is cold and humid, white smoke (condensation of moisture in saturated air) is generated in the cooling tower and released into the atmosphere. However, by introducing a portion of the low-temperature (80-150 degrees Celsius) exhaust gas emitted from the fuel cell and used as a cooling heat source for the high-efficiency dual-effect absorption chiller into the atmosphere into the cooling tower white smoke prevention device, white smoke can be prevented, thus preventing the freezing of surrounding facilities that may be caused by white smoke in winter.

Claims

1. The system comprises a fuel cell unit (100) that discharges exhaust gas generated during power generation and an absorption cooling unit (200) that utilizes the exhaust gas as a heat source, wherein the absorption cooling unit (200) includes: an absorption chiller (10) supplied with the exhaust gas as a heat source; an upper cooling tower (30) that lowers the temperature of the cooling water heated by the absorption chiller; a cooling water pump (40) that controls the flow of the cooling water; a chilled water pump (50) that controls the flow of the chilled water cooled by the absorption chiller; and the absorption cooling unit An absorption cooling system comprising: a system control unit (90) for controlling the drive of a to (200); a bypass valve (60) installed in a bypass pipe (12) for controlling the external discharge of the exhaust gas supplied from the fuel cell unit (100); an exhaust gas introduction valve (70) installed in an exhaust gas introduction pipe (13) for controlling the supply of the exhaust gas to the absorption chiller (10); and an exhaust gas fan (suction device) (20) for providing pressure so that the exhaust gas is supplied to the absorption chiller (10).

2. The absorption chiller according to claim 1 is a double-effect absorption chiller equipped with a regenerative heat exchanger (HTG, high-temperature regenerator), the regenerative heat exchanger (HTG, high-temperature regenerator) is equipped with a regenerator exhaust gas pipe (16) through which the exhaust gas supplied from the fuel cell unit (100) travels, and the exhaust gas fan (suction device) (20) is installed downstream of the regenerator exhaust gas pipe (16) in this absorption chiller system.

3. An absorption cooling system according to claim 1, further comprising: an exhaust gas discharge pipe (14) for discharging the exhaust gas discharged from the exhaust gas fan (suction device) (20) to the outside; a white smoke prevention pipe (15) connected to the exhaust gas discharge pipe (14) for transmitting the exhaust gas to the upper cooling tower (30); and a cooling tower introduction valve (80) for controlling the white smoke prevention pipe (15).

4. The absorption cooling system according to claim 1, characterized in that the system control unit (90) controls the opening and closing rate of the bypass valve (60) in accordance with the cooling drive conditions of the absorption cooling unit (200) in order to maintain the back pressure in the fuel cell unit (100) within a specified range when the absorption cooling unit (200) is driven to cool.

5. The absorption cooling system according to claim 4, characterized in that the cooling drive conditions of the absorption cooling unit (200) include the degree of operation of the exhaust gas fan (suction device) (20), the opening and closing rate of the exhaust gas introduction valve (70), the degree of operation of the cooling water pump (40), and the degree of operation of the chilled water pump (50).

6. The absorption cooling system according to claim 4, characterized in that when the absorption cooling system is at maximum load (S320), the system control unit (90) opens the exhaust gas introduction valve (70) to its maximum extent, drives the exhaust gas fan (suction device) (20) within a set high-load operating Hz range, and adjusts the opening and closing rate of the bypass valve (60) to maintain the back pressure in the fuel cell unit (100) within a specified range.

7. The absorption cooling system according to claim 4, characterized in that when the absorption cooling system is at partial load (S330), the system control unit (90) adjusts the degree of operation of the exhaust gas fan (suction device) (20) according to the cooling load of the absorption chiller (10), and the opening and closing rate of the bypass valve (60) is adjusted to maintain the back pressure in the fuel cell unit (100) within a specified range.

8. The absorption chiller (10) according to claim 1 further comprises an exhaust gas inlet temperature sensor (S1); an exhaust gas outlet temperature sensor (S2); and a regenerative heat exchanger temperature sensor (S3), wherein when the absorption chiller (10) is determined to be in an over-concentration state, the bypass valve (60) is fully opened, the exhaust gas introduction valve (70) is fully closed, the exhaust gas fan (suction device) (20) is stopped, and the current temperature of the chilled water outlet of the absorption chiller (10) is maintained until it rises to or above the restart temperature.

9. The absorption cooling system according to claim 3, wherein the upper cooling tower (30) comprises a fan (31), a cooling water spraying device (33) for spraying the cooling water, a packing material (34), and a white smoke prevention device (32), and when the conditions for the generation of white smoke in the upper cooling tower (30) are detected by the white smoke prevention device (32), the exhaust gas is supplied from the white smoke prevention piping (15) controlled by the cooling tower introduction valve (80) and supplied into the cooling tower (30) to prevent the white smoke phenomenon.

10. The absorption cooling system according to claim 9, characterized in that the white smoke prevention device (32) is located at the lower part of the upper cooling tower (30) and supplies the exhaust gas to the packing material (34) from the lower part upward.

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