Absorption chiller / heater

Abstract

To provide an absorption chiller / heater that can continue operating even if a condition arises where an inert gas for purging the fuel piping cannot be supplied. [Solution] An absorption chiller / heater that transfers heat through a cycle between a refrigerant and an absorbent liquid includes a regenerator having a combustor 71 that burns a gaseous fuel F mainly composed of hydrogen to generate heat for heating the absorbent liquid, a fuel pipe 72 that leads the fuel F to the combustor 71, an inert gas pipe 76 that supplies inert gas N to the fuel pipe 72, an inert gas detector 78 that detects whether or not inert gas N can be supplied to the fuel pipe 72, and a control device 60 that controls the combustion operation in the combustor 71. When the inert gas detector 78 detects that inert gas N cannot be supplied to the fuel pipe 72 while the fuel F is burning in the combustor 71, the control device 60 controls the combustion operation in the combustor 71 so as to continue the combustion of fuel F in the combustor 71 until it receives a command to stop the absorption chiller / heater.

Description

Technical Field

[0001] The present disclosure relates to an absorption chiller.

Background Art

[0002] An absorption chiller is a device that cools a cooling target medium (typically cold water) by taking away the latent heat of evaporation required when a refrigerant liquid evaporates into a refrigerant vapor in an evaporator. The refrigerant vapor generated in the evaporator is absorbed by an absorbent liquid in an absorber. The absorbent liquid in the absorber that has absorbed the refrigerant vapor and has a reduced concentration is sent to a regenerator and heated to increase its concentration. The absorbent liquid with an increased concentration in the regenerator is returned to the absorber and becomes capable of absorbing the refrigerant vapor generated in the evaporator again. One method of heating the absorbent liquid in the regenerator is to provide a combustion device that burns fuel in the regenerator. In recent years, as the adverse effects associated with global warming have been pointed out, using hydrogen as fuel has been studied to reduce greenhouse gas emissions. Since hydrogen is more flammable than fuels mainly composed of hydrocarbons such as city gas, a configuration for performing purge control with nitrogen gas in a hydrogen burner has been studied (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a combustion device having a hydrogen burner, as described in Patent Document 1, is applied to the regenerator of an absorption chiller, if it is detected that the inert gas (mainly nitrogen) used for inert gas purging to discharge flammable gas in the hydrogen piping has run out, the inert gas purging during shutdown cannot be performed, and control is performed to shut down the absorption chiller. However, even if the inert gas for inert gas purging is depleted, this does not directly affect the operation of the absorption chiller.

[0005] In view of the above-mentioned issues, this disclosure relates to providing an absorption chiller / heater that can continue operating even when a condition occurs in which an inert gas cannot be supplied. [Means for solving the problem]

[0006] An absorption chiller / heater according to a first aspect of the present disclosure is an absorption chiller / heater that transfers heat by a cycle of a refrigerant undergoing a phase change and an absorbent liquid mixed with the refrigerant, comprising: a regenerator having a combustor that burns a gaseous fuel mainly composed of hydrogen to generate heat for heating the absorbent liquid; a fuel pipe that leads the fuel to the combustor; an inert gas pipe that supplies an inert gas to the fuel pipe; an inert gas detector that detects whether or not the inert gas can be supplied to the fuel pipe; and a control device that controls the combustion operation in the combustor, wherein the control device controls the combustion operation in the combustor so as to continue the combustion of the fuel in the combustor until it receives a command to stop the absorption chiller / heater when the inert gas detector detects that the inert gas cannot be supplied to the fuel pipe while the fuel is burning in the combustor.

[0007] With this configuration, even if a situation arises where an inert gas cannot be supplied, which does not affect fuel combustion, combustion operation can continue.

[0008] Furthermore, as an absorption chiller / heater according to a second aspect of the present disclosure, in the absorption chiller / heater according to the first aspect of the present disclosure, the control device may issue an alert when the inert gas detector detects that the inert gas cannot be supplied to the fuel piping while the fuel is being burned in the combustor.

[0009] With this configuration, issuing an alert provides, for example, an opportunity for the recipient to resolve any deficiencies in the supply of inert gas.

[0010] Furthermore, as an absorption chiller according to a third aspect of the present disclosure, an absorption chiller according to the first or second aspect of the present disclosure is provided with a temperature-related value detector that detects the temperature of the absorbent liquid in the regenerator or a physical quantity related to that temperature, and the control device, when it receives a command to stop the absorption chiller while the inert gas detector has detected that the inert gas cannot be supplied to the fuel piping, may control the combustion operation in the combustor to perform a low-combustion operation that reduces the amount of combustion in the combustor to a lower value, thereby reducing the value detected by the temperature-related value detector to below the predetermined value, and then stopping the combustion of the fuel in the combustor.

[0011] With this configuration, even if the fuel remaining inside the fuel piping cannot be purged with an inert gas when combustion operation is stopped, the regenerator temperature can be lowered to reduce the likelihood of the remaining fuel inside the fuel piping igniting.

[0012] Furthermore, as an absorption chiller according to a fourth aspect of the present disclosure, an absorption chiller according to the first or second aspect of the present disclosure is equipped with a temperature-related value detector that detects the temperature of the absorbent liquid in the regenerator or a physical quantity related to that temperature, and the control device, when it receives a command to stop the absorption chiller while the inert gas detector has detected that it is not possible to supply the inert gas to the fuel piping, may control the combustion operation in the combustor to perform a low-combustion operation that reduces the amount of combustion in the combustor until a predetermined time has elapsed, and then stop the combustion of the fuel in the combustor, if the value detected by the temperature-related value detector exceeds a predetermined value.

[0013] With this configuration, even if the fuel remaining inside the fuel piping cannot be purged with an inert gas when combustion operation is stopped, the temperature of the regenerator can be lowered by performing low-combustion operation for a predetermined period of time, thereby reducing the likelihood of the fuel remaining inside the fuel piping igniting. [Effects of the Invention]

[0014] According to this disclosure, combustion operation can be continued even if a condition arises in which an inert gas cannot be supplied, which does not affect the combustion of the fuel. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram of an absorption chiller / heater according to an embodiment of the present disclosure. [Figure 2] This is a schematic diagram of the combustion device included in the absorption chiller / heater according to the embodiment of the present disclosure. [Figure 3] This is a block diagram illustrating the hardware configuration of a control device provided in the combustion device of an absorption chiller / heater according to an embodiment of the present disclosure. [Figure 4] This is a flowchart illustrating the control of the operation of an absorption chiller / heater according to an embodiment of the present disclosure. [Figure 5] Figure 4 is a flowchart that partially shows a modified example of the control of the operation. [Modes for carrying out the invention]

[0016] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, identical or equivalent components are denoted by the same or similar reference numerals, and redundant explanations are omitted. Also, the dimensions and proportions in the drawings are exaggerated for illustrative purposes and may differ from actual proportions.

[0017] First, with reference to Figure 1, the absorption chiller / heater 1 according to an embodiment of the present disclosure will be described. Figure 1 is a schematic diagram of the absorption chiller / heater 1. The absorption chiller / heater 1 includes an absorber 10, an evaporator 20, a regenerator 30, and a condenser 40 as the main components for performing the absorption cycle. The absorption chiller / heater 1 also includes a combustion device 70 and a control device 60. The absorption chiller / heater 1 is a device that performs heat transfer by circulating a refrigerant V through phase change with an absorbent liquid S, and typically lowers the temperature of chilled water C, which is the temperature-controlled medium, during cooling operation. The absorption chiller / heater 1 can typically perform both cooling and heating operations, and can perform both cooling and heating of chilled water, but in this disclosure, it will be described as a device that performs cooling operation (i.e., operation that lowers the temperature of chilled water C). Another feature of the absorption chiller / heater 1 is that it uses a gaseous fuel F mainly composed of hydrogen as the fuel supplied to the regenerator 30.

[0018] In the following description, with respect to the absorption liquid S, in order to facilitate distinction during the absorption cycle, depending on its properties and position in the absorption cycle, it is referred to as "dilute solution Sw", "concentrated solution Sa", etc., but when properties, etc. are not considered, it is collectively referred to as "absorption liquid S". Also, with respect to the refrigerant V, in order to facilitate distinction during the absorption cycle, depending on its properties and position in the absorption cycle, it is referred to as "evaporator refrigerant vapor Ve", "generator refrigerant vapor Vg", "refrigerant liquid Vf", etc., but when properties, etc. are not considered, it is collectively referred to as "refrigerant V". In this embodiment, an aqueous solution of lithium bromide (LiBr) is used as the absorption liquid S (typically a mixture of an absorbent and a refrigerant), and water (H2O) is used as the refrigerant V, but it is not limited to this and other combinations of refrigerants and absorption liquids (or absorbents) may be used.

[0019] The absorber 10 is a device that absorbs the evaporator refrigerant vapor Ve generated in the evaporator 20 with the concentrated solution Sa. The absorber 10 has, inside the absorber cylinder 17, a cooling pipe 11 as a cooling water flow path through which cooling water D flows, and a concentrated solution spray nozzle 12 that sprays the concentrated solution Sa toward the outer surface of the cooling pipe 11. The concentrated solution spray nozzle 12 is disposed above the cooling pipe 11 such that the sprayed concentrated solution Sa falls onto the cooling pipe 11. The absorber 10 stores, in the lower part of the absorber cylinder 17, the dilute solution Sw with a reduced concentration as the sprayed concentrated solution Sa absorbs the evaporator refrigerant vapor Ve. In the absorber 10, the cooling water D takes away (i.e., removes) the heat of absorption generated when the evaporator refrigerant vapor Ve is absorbed by the concentrated solution Sa.

[0020] The cooling pipe 11 is connected to a cooling water inlet pipe 11a for allowing cooling water D to flow in at one end (or the first end). A cooling water connecting pipe 14 is connected to the other end (or the second end) of the cooling pipe 11. The cooling water inlet pipe 11a is connected to a cooling water supply pipe 98 outside the absorption chiller 1. The cooling water supply pipe 98 is connected to a cooling tower (not shown) outside the absorption chiller 1. A cooling water pump 91 outside the absorption chiller 1 is disposed in the cooling water supply pipe 98. The absorption chiller 1 allows the cooling water D to flow through the cooling pipe 11 by the operation of the cooling water pump 91. The cooling water pump 91 may be able to adjust the discharge flow rate of the cooling water D by an inverter.

[0021] The evaporator 20 is a device that cools the chilled water C by taking away the latent heat of evaporation required when the refrigerant liquid Vf undergoes a phase change into the evaporator refrigerant vapor Ve from the chilled water C. The evaporator 20 has, inside the evaporator cylinder 27, an evaporation pipe 21 as a chilled water flow path for flowing the chilled water C, and a refrigerant liquid spray nozzle 22 for spraying the refrigerant liquid Vf toward the outer surface of the evaporation pipe 21. The refrigerant liquid spray nozzle 22 is disposed above the evaporation pipe 21 so that the sprayed refrigerant liquid Vf falls onto the evaporation pipe 21. The evaporator 20 further has a refrigerant liquid pipe 28 for guiding the refrigerant liquid Vf stored in the lower part of the evaporator cylinder 27 to the refrigerant liquid spray nozzle 22, and a refrigerant pump 29 for sending the refrigerant liquid Vf in the refrigerant liquid pipe 28 to the refrigerant liquid spray nozzle 22. The evaporator 20 cools the chilled water C by taking away the heat of vaporization for the sprayed refrigerant liquid Vf to evaporate into the evaporator refrigerant vapor Ve from the chilled water C flowing through the evaporation pipe 21, and stores the refrigerant liquid Vf that has not evaporated among the sprayed refrigerant liquid Vf in the lower part of the evaporator cylinder 27.

[0022] A chilled water inlet pipe 21a for introducing chilled water C is connected to one end (or first end) of the evaporator tube 21. A chilled water outlet pipe 21b for carrying the chilled water C that has flowed out of the evaporator tube 21 is connected to the other end (or second end) of the evaporator tube 21. A chilled water return pipe 95, located outside the absorption chiller / heater 1, is connected to the chilled water inlet pipe 21a. A chilled water supply pipe 96, also located outside the absorption chiller / heater 1, is connected to the chilled water outlet pipe 21b. The chilled water return pipe 95 and the chilled water supply pipe 96 are connected to a heat utilization device (not shown) that utilizes the cold energy contained in the chilled water C. A chilled water pump 92, located outside the absorption chiller / heater 1, is installed in the chilled water return pipe 95. The absorption chiller / heater 1 allows chilled water C to flow through the evaporator tube 21 due to the operation of the chilled water pump 92. The chilled water pump 92 may be able to adjust the discharge flow rate of chilled water C using an inverter.

[0023] In this embodiment, the absorber 10 and the evaporator 20 are arranged adjacent to each other, and the upper part of the absorber shell 17 and the upper part of the evaporator shell 27 are in communication. This configuration allows the evaporator refrigerant vapor Ve generated inside the evaporator shell 27 to be guided into the absorber shell 17.

[0024] The regenerator 30 is a device that generates a concentrated solution Sa by introducing a dilute solution Sw and heating it to release the refrigerant V from the dilute solution Sw. In the regenerator 30, the refrigerant V released from the dilute solution Sw is in the form of vapor, and this vapor of refrigerant V will be referred to as the regenerator refrigerant vapor Vg. The regenerator 30 is equipped with a combustion device 70 for heating the dilute solution Sw. The regenerator 30 has a regenerator shell 37 for storing the introduced absorbent liquid S. Inside the regenerator shell 37 is a combustor 71, which is one of the elements that make up the combustion device 70. The combustor 71 can generate combustion heat by introducing fuel F and air A and burning the fuel F. The regenerator 30 can generate heat to heat the dilute solution Sw by burning fuel F in the combustor 71. The detailed configuration of the combustion device 70 will be described later.

[0025] The condenser 40 is a device that introduces regenerator refrigerant vapor Vg evaporated from the dilute solution Sw in the regenerator 30, cools and condenses it, and generates refrigerant liquid Vf to be sent to the evaporator 20. The condenser 40 has a condensing pipe 41 inside the condenser shell 47, which is a component that forms a flow path (or cooling water flow path) for the cooling water D. In this embodiment, one end (or first end) of the condensing pipe 41 is connected to the other end (or second end) of the cooling water connecting pipe 14. One end (or first end) of the cooling water connecting pipe 14 is connected to the cooling pipe 11 as described above. The other end (or second end) of the condensing pipe 41 is connected to a cooling water outlet pipe 41b that carries the cooling water D that has flowed out of the condensing pipe 41. The cooling water return pipe 99 outside the absorption chiller 1 is connected to the cooling water outlet pipe 41b. The cooling water return pipe 99 is connected to a cooling tower (not shown) outside the absorption chiller 1. With this configuration, the cooling water D flowing through the cooling water return pipe 99 is cooled in a cooling tower (not shown) and supplied to the cooling water supply pipe 98.

[0026] The condenser shell 47 is positioned close to the regenerator shell 37. In this embodiment, the upper part of the regenerator shell 37 and the upper part of the condenser shell 47 are in communication via a regenerator refrigerant vapor passage 35 (which is composed of, for example, piping). The condenser 40 receives regenerator refrigerant vapor Vg from the regenerator 30 via the regenerator refrigerant vapor passage 35, and the cooling water D flowing through the condensing pipe 41 removes heat from the regenerator refrigerant vapor Vg, thereby condensing it into refrigerant liquid Vf. In other words, the cooling water D flowing through the condensing pipe 41 removes the heat of condensation generated when the regenerator refrigerant vapor Vg undergoes a phase change to refrigerant liquid Vf. In this embodiment, the condenser shell 47 and the regenerator shell 37 are positioned above the evaporator shell 27 and the absorber shell 17. The bottom or lower part of the condenser shell 47 and the evaporator shell 27 are connected by a condensing refrigerant liquid pipe 48. This configuration allows the refrigerant liquid Vf in the condenser shell 47 to be guided into the evaporator shell 27 by the position head and the difference in internal pressure between the two.

[0027] The bottom or lower part of the absorber shell 17 and the regenerator shell 37 are connected by a dilute solution pipe 18. A solution pump 19 is installed in the dilute solution pipe 18. The absorption chiller 1 can transport the dilute solution Sw from the absorber shell 17 into the regenerator shell 37 using the solution pump 19. Inside the regenerator shell 37, as the introduced dilute solution Sw moves from the inlet to the outlet, the refrigerant V is released from the dilute solution Sw and its concentration increases. The part of the regenerator shell 37 where the concentrated solution Sa flows out is connected to the concentrated solution spray nozzle 12 of the absorber 10 by a concentrated solution pipe 38. A concentrated solution thermometer 53 is provided in the concentrated solution pipe 38 near the regenerator 30 to detect the temperature of the concentrated solution Sa flowing out of the regenerator 30. The concentrated solution thermometer 53 is a device that detects the outlet temperature of the absorbent liquid S in the regenerator 30 and corresponds to a temperature-related value detector. A concentrated solution thermometer 53 may be provided in the regenerator shell 37. In the absorption chiller 1, a dilute solution Sw is transported to the regenerator shell 37 by a solution pump 19, and the concentrated solution Sa generated by the detachment of the refrigerant V within the regenerator shell 37 is introduced to the concentrated solution spray nozzle 12 via the concentrated solution pipe 38. Solution heat exchangers 81 are inserted into the dilute solution pipe 18 and the concentrated solution pipe 38 to facilitate heat exchange between the dilute solution Sw flowing through the dilute solution pipe 18 and the concentrated solution Sa flowing through the concentrated solution pipe 38.

[0028] The combustion device 70 provided in the regenerator 30 will now be explained with reference to Figure 2. Figure 2 is a schematic diagram of the combustion device 70. The combustion device 70 is suitable for burning a gaseous fuel F mainly composed of hydrogen. Here, the gas mainly composed of hydrogen is a gas containing 50% or more by volume of hydrogen, typically a gas containing 80% or more by volume of hydrogen, and may also be a gas that is 100% hydrogen. The combustion device 70 includes a combustor 71, a mechanism for supplying fuel F to the combustor 71, a mechanism for supplying nitrogen N as an inert gas, and a mechanism for supplying air A to the combustor 71, and further includes a control device 60.

[0029] The combustor 71 is a device that introduces fuel F and air A and generates combustion heat by burning the fuel F. The combustor 71 may have a pilot burner in addition to the main burner. The combustor 71 is connected to a fuel pipe 72 that leads fuel F to the combustor 71 and an air pipe 82 that leads air A to the combustor 71.

[0030] Fuel piping 72 has a combustor 71 connected to its first end and a fuel source 73 connected to its second end opposite the first end. The fuel source 73 may be, for example, a source of gas that becomes fuel F, such as a hydrogen production process, a conduit for supplying commercial hydrogen, or a cylinder filled with fuel F. The fuel F flowing through fuel piping 72 may be pure hydrogen or by-product hydrogen. Fuel piping 72 carries fuel F from fuel source 73 towards combustor 71, that is, from the second end to the first end. Fuel piping 72 is provided with a fuel shut-off valve 74 and a fuel control valve 75. The fuel shut-off valve 74 is a valve that shuts off the flow of fuel F through fuel piping 72, and a solenoid valve may be used. The fuel control valve 75 is a valve that adjusts the flow rate of fuel F introduced into combustor 71, and an electric valve may be used. The fuel control valve 75 may be capable of continuously adjusting the flow rate of fuel F introduced into the combustor 71 by changing its opening degree in response to a command from the control device 60. The fuel shut-off valve 74 is located upstream of the fuel control valve 75 when viewed in the direction of fuel F flow. The fuel piping 72, fuel source 73, fuel shut-off valve 74, and fuel control valve 75 correspond to the mechanism for supplying fuel F to the combustor 71.

[0031] The combustion device 70 has a mechanism for supplying nitrogen (N), which supplies nitrogen (N) to the fuel piping 72. The fuel F burned in the combustor 71 is a gas mainly composed of hydrogen, so compared to fuels mainly composed of hydrocarbons such as city gas, it has a wider combustion range and a faster combustion speed, making it easier to ignite. Taking this into consideration, the combustion device 70 is equipped with a mechanism to supply nitrogen (N) to replace the fuel F in the fuel piping 72 with nitrogen (N) when stopped, in order to prevent some of the fuel F in the fuel piping 72 from entering the combustion range by being replaced by air and unexpectedly burning, so that no fuel F remains in the fuel piping 72. In this embodiment, nitrogen (N) is used as the substance to replace the fuel F in the fuel piping 72, but an inert gas other than nitrogen (N) may also be used. In this context, inert gases are a general term for gases that are chemically stable and do not readily react with other elements or compounds. These include noble gases (i.e., the six elements of Group 0 of the periodic table: He, Ne, Ar, Kr, Xe, and Rn), as well as nitrogen and carbon dioxide, which are far less reactive than oxygen. Of these inert gases, nitrogen (N) is used in this embodiment for its availability. Nitrogen (N) commonly used in industrial applications can be used.

[0032] The combustion device 70 includes a nitrogen pipe 76 and a nitrogen source 77 as a mechanism for supplying nitrogen N. The nitrogen pipe 76 is a pipe that supplies nitrogen N to the fuel pipe 72 and corresponds to an inert gas pipe. The first end of the nitrogen pipe 76 is typically connected to the fuel pipe 72 between the fuel shut-off valve 74 and the fuel control valve 75. The second end of the nitrogen pipe 76, opposite to the first end, is connected to the nitrogen source 77. The nitrogen source 77 is the source of nitrogen N supplied to the fuel pipe 72 and may be, for example, extracted from a process in which nitrogen is used, or it may be a cylinder in which nitrogen N is stored. The nitrogen pipe 76 is provided with a nitrogen shut-off valve 79 for shutting off the flow of nitrogen N through the nitrogen pipe 76 and a check valve 80 for preventing backflow of hydrogen.

[0033] A pressure switch 78 is provided in the nitrogen piping 76 between the nitrogen source 77 and the nitrogen shut-off valve 79. The pressure switch 78 is a switch that turns on when the pressure inside the nitrogen piping 76 to be detected falls below a predetermined pressure, and is sometimes referred to as a low-pressure switch. The predetermined pressure is typically the minimum pressure at which the amount of nitrogen N necessary to replace the fuel F inside the fuel piping 72 with nitrogen N can be supplied. Therefore, when the pressure switch 78 turns on, it means that the required amount of nitrogen N cannot be supplied from the nitrogen source 77 to the nitrogen piping 76. In this way, the pressure switch 78 detects whether or not nitrogen N, a form of inert gas, can be supplied to the fuel piping 72, and is equivalent to an inert gas detector.

[0034] An air pipe 82 that leads air A to the combustor 71 has the combustor 71 connected to its first end and an air fan 83 connected to its second end opposite the first end. The air fan 83 is a device that pressurizes the air around the combustion device 70 and sends it toward the combustor 71. An air control valve 85 is provided in the air pipe 82. The air control valve 85 is a valve that adjusts the flow rate of air A introduced into the combustor 71, and an electric valve may be used. The air control valve 85 may be capable of continuously adjusting the flow rate of air A introduced into the combustor 71 by changing its opening degree in response to a command from the control device 60. In this embodiment, the opening degree of the air control valve 85 can be adjusted independently of the operation of the fuel control valve 75, but the opening degree of the air control valve 85 and the opening degree of the fuel control valve 75 may be adjusted in a linked (i.e., interlocked) manner. Alternatively, instead of, or in conjunction with, being able to continuously change the opening degree of the air control valve 85, the flow rate of air A flowing through the air piping 82 may be adjusted by controlling the air fan 83 with an inverter.

[0035] The control device 60 is a device that controls the operation of the combustion apparatus 70, including the combustion operation in the combustor 71. Here, controlling the combustion operation typically means starting and stopping combustion and adjusting the amount of combustion. The control device 60 has a control unit 61, a communication unit 62, and a storage unit 63. Although these units are distinguished by function for the sake of explanation, they are typically configured as a single integrated unit within the control device 60, or one or more of these units may be physically separated, or one unit may be physically divided into multiple units.

[0036] The control unit 61 is the part that controls the operation of each device and equipment that constitutes the combustion device 70. The control unit 61 is connected to the fuel shut-off valve 74 and the nitrogen shut-off valve 79 by communication lines (wired or wireless; the same applies hereinafter), and controls the opening and closing of these valves. The control unit 61 is also connected to the fuel control valve 75 and the air control valve 85 by communication lines, and controls the opening of these valves to an arbitrary opening typically between 0% and 100%. The control unit 61 is also connected to the air fan 83 by a communication line, and typically controls the starting and stopping of the air fan 83, but may also control the rotational speed of the air fan 83. The control unit 61 also has a timing means for measuring time, such as a clock or timer. The control unit 61 may also have a program for properly operating each of the above-mentioned devices and equipment. The control unit 61 may include a physical configuration of a processor and / or memory (RAM).

[0037] The communication unit 62 is the part that sends and receives signals to and from instruments or equipment. The communication unit 62 is connected to the pressure switch 78 by a communication line and receives a signal when the pressure switch 78 is turned on. The communication unit 62 is also connected to the concentrated solution thermometer 53 (see Figure 1) by a communication line and receives information about the temperature detected by the concentrated solution thermometer 53 as a signal. The communication unit 62 also emits alarms to external monitoring panels (not shown) or terminals (not shown). An alarm typically involves issuing a signal to draw attention, and includes pre-alarms and error alarms. In this disclosure, a pre-alarm is a minor notification and is indicated by a lamp or text message without making a sound, while an error alarm is a moderate or severe notification and is indicated by a lamp or text message accompanied by a warning sound. The communication unit 62 may be configured as a communication interface.

[0038] The storage unit 63 is the part that stores programs and data necessary for the operation of the combustion device 70. The storage unit 63 may also store sequences related to the operation of the combustion device 70. In addition, the storage unit 63 may store the standard opening degrees of the fuel control valve 75 and the air control valve 85 in combustion conditions such as rated combustion operation and low combustion operation. The storage unit 63 may also include a physical configuration of storage and / or memory (RAM and / or ROM).

[0039] As shown in Figure 1, the control device 60 in this embodiment not only controls the operation of the combustion device 70 but also controls the operation of the absorption chiller / heater 1. The control unit 61 is connected to the solution pump 19 and the refrigerant pump 29 by communication lines and controls the start / stop and discharge flow rate of each pump 19 and 29. The control unit 61 is also connected to the cooling water pump 91 and the chilled water pump 92 by communication lines and controls the start / stop and discharge flow rate of each pump 91 and 92. The communication unit 62 is connected by communication lines to instruments installed in appropriate locations to grasp the operating status of the absorption chiller / heater 1 and receives information detected by these instruments as signals. The storage unit 63 stores a program that controls the operation of the absorption chiller / heater 1.

[0040] The hardware configuration of the control device 60 will now be explained with reference to the block diagram shown in Figure 3. The block diagram in Figure 3 shows the concept of the physical configuration of the control device 60. The control device 60 has a processor 65, memory 66, storage 67, and a communication interface 68. The control device 60 may also be a computer.

[0041] The processor 65 processes various types of information in the control unit 60. This information includes the content and transmission timing of control signals transmitted to each device and equipment constituting the absorption chiller 1. The processor 65 may be a single processor or two or more processors. The operation of the processor 65 may be performed not only by a single processor 65, but also by the cooperation of multiple processors 65 located in physically separate locations. The processor 65 may include a central processing unit (CPU), a graphics processing unit (GPU), a microprocessor, a circuit board, or other electrical circuits. The processor 65 can execute programs, manipulate data, and perform operations of the control unit 60, including operations using any algorithms, methods, functions, processes, and procedures described herein.

[0042] Memory 66 (which can also be considered as the first memory) temporarily or permanently stores programs and / or data used for information processing in the control device 60. Memory 66 may also store programs used by the control device 60 when making various judgments and decisions. These programs can be added and modified retrospectively (i.e., after the control device 60 is manufactured). Memory 66 may be a single memory or two or more memories. Memory 66 may include volatile memory such as RAM and cache, and non-volatile memory such as ROM.

[0043] The storage 67 (which can also be considered as a second memory) temporarily or permanently records programs and / or data used for information processing in the control device 60. The storage 67 may also store the relationship between values ​​detected by measuring instruments and their substitute values. Furthermore, the storage 67 can record data regarding the operating status of the absorption chiller 1, as needed. The storage 67 may hold other programs, including an operating system, that can be executed in the control device 60 or other devices. The storage 67 may include a hard disk drive (HDD), a solid-state drive (SSD), and / or flash memory, etc.

[0044] The communication interface 68 communicates with the fuel shut-off valve 74 and the nitrogen shut-off valve 79, and transmits control signals to these valves 74 and 79 regarding opening and closing. The communication interface 68 also communicates with the fuel control valve 75 and the air control valve 85, and transmits control signals to these valves 75 and 85 regarding their opening degree. The communication interface 68 also communicates with the air fan 83, and transmits control signals to the air fan 83 regarding starting and stopping. The communication interface 68 also communicates with the pressure switch 78 and receives a control signal from the pressure switch 78 indicating that it has been turned on. The communication interface 68 also communicates with the concentrated solution thermometer 53 and receives control signals from the concentrated solution thermometer 53 regarding temperature. The communication interface 68 also communicates with the solution pump 19, refrigerant pump 29, cooling water pump 91, and chilled water pump 92, and transmits control signals to these pumps 19, 29, 91, and 92 regarding starting and stopping and discharge flow rate. The communication interface 68 can also receive control signals regarding the operating status of the absorption chiller 1 as needed. The communication interface 68 may have the function of sending and receiving signals in the communication unit 62.

[0045] Each component of the control device 60 (including the processor 65, memory 66, storage 67, and communication interface 68) is connected to each other by a bus, such as a system bus or control bus, and can communicate with each other. The control device 60 also has a power supply 69. The power supply 69 typically includes a power plug that draws power from a commercial power supply or other power source. The power supply 69 may include a replaceable or non-replaceable battery, which may be able to be charged by receiving power from a commercial power supply or other power source.

[0046] In the above description of the hardware configuration of the control device 60, the programs and / or data stored in the memory 66 and / or storage 67 may also be stored on a non-temporary computer-readable medium. The non-temporary computer-readable medium stores computer-readable instructions and / or data that are used by a computer to perform a method performed by the computer. The computer-readable medium may include magneto-optical disks and optical memory devices, as well as digital video discs (DVDs), CD-ROMs, DVD+ / -R, DVD-RAM, DVD-ROMs, HD-DVDs, and BLURAY®. The computer-readable medium may also include magnetic devices such as tapes, cartridges, cassettes, and removable disks. Each program (including program products) may include one or more modules of computer program instructions encoded on a tangible non-temporary computer-readable medium for execution by an information processing device including a computer (control device 60 in this embodiment) or for controlling the operation of the information processing device. The programs and / or data may also be downloaded from an external device via a network.

[0047] Next, the operation of the absorption chiller / heater 1 will be explained with reference to Figures 1 and 2. Note that, unless otherwise specified, the operation of each device connected to the control device 60 by communication lines is typically controlled by the control device 60. When the absorption chiller / heater 1 is started, inert gas pre-purging of the fuel piping 72 is performed before combustion begins in the combustor 71. During the inert gas pre-purging of the fuel piping 72, the fuel shut-off valve 74 is closed, and the fuel control valve 75 and nitrogen shut-off valve 79 are opened. This allows nitrogen N to flow into the fuel piping 72 and combustor 71 downstream of the fuel shut-off valve 74. Additionally, the air control valve 85 is opened and the air fan 83 is started. This allows air A to flow into the air piping 82 and combustor 71. In this way, any unburned fuel F present in the combustor 71 is discharged from the fuel piping 72 and regenerator 30. Once the inert gas pre-purging in the fuel piping 72 and the regenerator 30 is complete, the nitrogen shut-off valve 79 is closed, and then the fuel shut-off valve 74 is opened. This supplies fuel F and air A to the combustor 71, and combustion of fuel F in the combustor 71 begins. When combustion of fuel F in the combustor 71 begins, it is preferable that combustion is first performed in the pilot burner to generate a pilot flame, and then combustion is performed in the main burner. If a pilot burner is used, the hydrogen piping of the pilot burner is also purged with inert gas before and after combustion. However, if the pilot burner piping is of a length where flashback is not a problem, the inert gas purging of the pilot burner piping may be omitted.

[0048] When the absorption chiller 1 is started and the inert gas pre-purging described above is completed or while the inert gas pre-purging is being performed, the cooling water pump 91 and the chilled water pump 92 are started. When the cooling water pump 91 is operating, the cooling water D circulates in this embodiment through the cooling water supply pipe 98, cooling water inlet pipe 11a, cooling pipe 11, cooling water connecting pipe 14, condensing pipe 41, cooling water outlet pipe 41b, cooling water return pipe 99, and cooling tower (not shown). When the chilled water pump 92 is operating, the chilled water C circulates through the chilled water return pipe 95, chilled water inlet pipe 21a, evaporator pipe 21, chilled water outlet pipe 21b, chilled water supply pipe 96, and heat utilization equipment (not shown). Once the cooling water pump 91 and the chilled water pump 92 are started, the solution pump 19 and the refrigerant pump 29 are started in an appropriate time.

[0049] Regarding the absorption cycle, looking at the cycle on the refrigerant V side, the regenerator refrigerant vapor Vg introduced from the regenerator 30 to the condenser 40 via the regenerator refrigerant vapor flow path 35 is cooled and condensed by the cooling water D flowing through the condensing pipe 41, becoming refrigerant liquid Vf which is stored at the bottom of the condenser shell 47. The cooling water D that has cooled the regenerator refrigerant vapor Vg has increased in temperature and flows out from the cooling water return pipe 99 and is supplied to the cooling tower (not shown). The refrigerant liquid Vf in the condenser shell 47 is introduced into the evaporator shell 27 via the condensing refrigerant liquid pipe 48.

[0050] The refrigerant liquid Vf introduced from the condenser shell 47 into the evaporator shell 27 mixes with the refrigerant liquid Vf that was sprayed from the refrigerant liquid spray nozzle 22 and did not evaporate, and is stored in the lower part of the evaporator shell 27. The refrigerant liquid Vf in the evaporator shell 27 flows through the refrigerant liquid pipe 28 via the refrigerant pump 29 to the refrigerant liquid spray nozzle 22. The refrigerant liquid Vf that reaches the refrigerant liquid spray nozzle 22 is sprayed toward the evaporator pipe 21, where it absorbs heat from the chilled water C flowing through the evaporator pipe 21, and a portion of it evaporates to become evaporator refrigerant vapor Ve, which is then introduced into the absorber shell 17. The chilled water C, having lost heat to the sprayed refrigerant liquid Vf, cools down and flows out of the evaporator pipe 21, where it is supplied to heat utilization equipment (not shown), such as an air conditioner. The refrigerant liquid Vf that was sprayed from the refrigerant liquid spray nozzle 22 and did not evaporate mixes with the refrigerant liquid Vf introduced from the condenser shell 47 and is stored in the lower part of the evaporator shell 27.

[0051] Next, looking at the cycle on the solution S side of the absorption chiller / heater 1, the concentrated solution Sa that flows out from the regenerator 30 into the concentrated solution pipe 38 flows through the concentrated solution pipe 38, exchanges heat with the dilute solution Sw in the solution heat exchanger 81, and after its temperature decreases, reaches the concentrated solution spray nozzle 12. The concentrated solution Sa that reaches the concentrated solution spray nozzle 12 is sprayed toward the cooling pipe 11, absorbs the evaporator refrigerant vapor Ve introduced from the evaporator 20, and its concentration decreases to become the dilute solution Sw. When the concentrated solution Sa absorbs the evaporator refrigerant vapor Ve inside the absorber shell 17, absorption heat is generated. This generated absorption heat is removed by the cooling water D flowing through the cooling pipe 11. In this embodiment, the cooling water D flowing through the cooling pipe 11 absorbs the absorption heat, its temperature rises, and it flows out into the cooling water connecting pipe 14 and is supplied to the condensing pipe 41 of the condenser 40. The dilute solution Sw generated inside the absorber shell 17 is stored inside the absorber shell 17.

[0052] The dilute solution Sw in the absorber shell 17 flows through the dilute solution tube 18 via the solution pump 19, and after its temperature rises in the solution heat exchanger 81, it is introduced into the regenerator shell 37. The dilute solution Sw introduced into the regenerator shell 37 is heated by the heat of combustion when the fuel F is burned in the combustor 71, causing the refrigerant V to detach and become a concentrated solution Sa. The refrigerant V that has been heated by the heat of combustion and detached from the dilute solution Sw is sent into the condenser shell 47 as regenerator refrigerant vapor Vg via the regenerator refrigerant vapor flow path 35. The concentrated solution Sa generated in the regenerator shell 37 flows out into the concentrated solution tube 38.

[0053] When a command to stop the absorption chiller / heater 1 is input to the absorption chiller / heater 1, the absorption chiller / heater 1 proceeds to the stopping procedure. When the absorption chiller / heater 1 stops, a dilution operation is performed. The dilution operation may involve sending the refrigerant liquid Vf stored inside the evaporator shell 27 into the absorber shell 17 to dilute the absorbent liquid S. Also, when the absorption chiller / heater 1 stops, an inert gas post-purge is performed in the fuel piping 72 and the regenerator 30. During the inert gas post-purge of the fuel piping 72, the fuel shut-off valve 74 is closed and the nitrogen shut-off valve 79 is opened. As a result, the fuel F remaining in the fuel piping 72 and combustor 71 downstream of the fuel shut-off valve 74 is discharged into the regenerator 30 by nitrogen N. At this time, since the air fan 83 continues to operate, the fuel F discharged into the regenerator 30 is discharged into the atmosphere. After a predetermined time has elapsed since the start of the inert gas post-purging of the fuel piping 72, the nitrogen shut-off valve 79 is closed, and after a further predetermined time has elapsed, the air fan 83 is stopped. In addition, the solution pump 19, refrigerant pump 29, cooling water pump 91, and chilled water pump 92 are stopped in appropriate times depending on the status of the dilution operation described above. In this way, the absorption chiller 1 is brought to a stopped state.

[0054] In the absorption chiller / heater 1 described herein, the fuel F burned in the combustor 71 is a gaseous fuel mainly composed of hydrogen, and therefore is more easily ignited than fuels mainly composed of hydrocarbons such as city gas. For this reason, when the absorption chiller / heater 1 is stopped, the conditions for fuel F to ignite are not met, that is, air A and the heat required for ignition are not supplied to the fuel F. To achieve this, it is common practice to purge the fuel piping 72 downstream of the fuel shut-off valve 74 and inside the combustor 71 with nitrogen N (i.e., an inert gas) as described above, in order to prevent fuel F from remaining in these areas. However, during the operation of the absorption chiller / heater 1, a situation may occur where the supply of nitrogen N (i.e., an inert gas) to the combustion device 70 becomes impossible due to some reason, such as the shutdown of the process supplying the nitrogen N (i.e., an inert gas) or the depletion of nitrogen N in the cylinder. In the conventional approach, if the supply of inert gas becomes impossible, the device is immediately stopped and an alarm is issued. However, if such conventionally conceivable measures are applied to the absorption chiller 1, the fuel F will not be purged with inert gas, and the high-temperature absorption chiller 1 will be shut down with fuel F remaining in the fuel piping 72 and combustor 71. In this state, if some of the fuel F remaining in the fuel piping 72 and combustor 71 is replaced with air, the hydrogen concentration will fall within the combustion range, creating a risk of combustion inside the fuel piping 72. On the other hand, the inability to supply nitrogen N to the combustion device 70, while meaning that the fuel F cannot be purged with inert gas, does not affect the continued operation of the absorption chiller 1. In light of these circumstances, the absorption chiller 1 according to this disclosure is designed to perform the following control.

[0055] Figure 4 is a flowchart illustrating the control of the operation of the absorption chiller / heater 1. In the following description of the control, when the configuration of the absorption chiller / heater 1 is referred to, please refer to Figures 1 and 2 as appropriate. The following control is typically executed by the control device 60 when the control unit 61 and the communication unit 62 are activated based on a program stored in the memory unit 63. When the absorption chiller / heater 1, which is in a stopped state, receives a start signal (St1), the control device 60 checks whether the pressure switch 78 is ON or OFF (St2). If the pressure switch 78 is ON (YES in St2), it means that inert gas purging using nitrogen N cannot be performed because nitrogen N supplied from the nitrogen source 77 is absent or insufficient, so an error alarm is issued and the start process is stopped (St3). On the other hand, if the pressure switch 78 is OFF (NO in St2), as described above, inert gas pre-purging is performed (St4), and then combustion of fuel F in the combustor 71 is started (St5). Furthermore, around the time of the start of combustion (St5), as described above, the cooling water pump 91, chilled water pump 92, solution pump 19, and refrigerant pump 29 are started in an appropriate manner, and the absorption chiller 1 enters a steady-state operation.

[0056] During steady-state operation of the absorption chiller / heater 1, the control device 60 determines whether the pressure switch 78 is turned on or not (i.e., whether it has received a signal that the pressure switch 78 is on) (St6). If the pressure switch 78 is not turned on (NO in St6), the control device 60 determines whether it has received a command to stop the absorption chiller / heater 1 (St7). If it has not received a command to stop the absorption chiller / heater 1 (NO in St7), it returns to the step of determining whether the pressure switch 78 was turned on or not during steady-state operation of the absorption chiller / heater 1 (St6). As a result, steady-state operation continues. In other words, combustion in the combustor 71 necessary for steady-state operation of the absorption chiller / heater 1 continues until it receives a command to stop the operation of the absorption chiller / heater 1. On the other hand, if it receives a command to stop the absorption chiller / heater 1 (YES in St7), the inert gas post-purge described above is performed (St8), and then the absorption chiller / heater 1 is stopped (St15).

[0057] In the process of determining whether the pressure switch 78 is turned on during steady-state operation of the absorption chiller / heater 1 (St6), if the pressure switch 78 is turned on (YES in St6), the control device 60 issues a pre-alarm (St9). The pre-alarm issued here typically informs relevant parties (e.g., the manager or user of the absorption chiller / heater 1) that nitrogen N cannot be supplied. By issuing a pre-alarm, relevant parties are given an opportunity to rectify the defect that prevents the supply of nitrogen N. Although the issuance of a pre-alarm means that nitrogen N cannot be supplied, as mentioned above, nitrogen N is not necessary to maintain steady-state operation of the absorption chiller / heater 1. Therefore, steady-state operation is continued without error shutdown of the absorption chiller / heater 1 until a command to stop the absorption chiller / heater 1 is received.

[0058] When a pre-alarm is triggered (St9), the control device 60 determines whether the pressure switch 78 has been turned off (i.e., whether the pressure switch 78 has been turned off) (St10). Personnel who recognize that nitrogen N cannot be supplied due to the pre-alarm may turn off the pressure switch 78 by repairing the process or replacing the cylinder with one filled with nitrogen N. If the pressure switch 78 has been turned off (YES in St10), the process returns to determining whether the pressure switch 78 was turned on during steady operation of the absorption chiller 1 (St6). On the other hand, if the pressure switch 78 has not been turned off (NO in St10), the control device 60 determines whether it has received a command to stop the absorption chiller 1 (St11). If it has not received a command to stop the absorption chiller 1 (NO in St11), the process returns to determining whether the pressure switch 78 has been turned off (St10). In this way, even when nitrogen (N) cannot be supplied, unless a command is received to stop the absorption chiller / heater 1, the steady-state operation of the absorption chiller / heater 1 and, consequently, the combustion in the combustor 71 necessary for the steady-state operation of the absorption chiller / heater 1 continues.

[0059] In the step of determining whether or not a command to stop the absorption chiller / heater 1 has been received (St11), if a command to stop the absorption chiller / heater 1 has been received (YES in St11), the control device 60 determines whether or not the temperature detected by the concentrated solution thermometer 53 exceeds a predetermined temperature (St12). The predetermined temperature is a temperature at which the possibility of ignition of the remaining fuel F in the fuel piping 72 is low, even if fuel F remains in the fuel piping 72 as a result of the absorption chiller / heater 1 being stopped without inert gas post-purging. The predetermined temperature may be, for example, 100°C or around 100°C, or any temperature may be set from 80°C to 120°C.

[0060] If the temperature detected by the concentrated solution thermometer 53 exceeds a predetermined temperature (YES in St12), the control device 60 estimates that there is a significant possibility that the remaining fuel F will ignite and switches the combustion device 70 to low-combustion operation (St13). Low-combustion operation typically involves reducing the amount of fuel F burned in the combustor 71 to suppress the amount of heat generated, thereby reducing the temperature of the concentrated solution Sa flowing out of the regenerator 30, in other words, the value detected by the concentrated solution thermometer 53. By performing low-combustion operation and lowering the temperature of the absorbent liquid S inside the regenerator shell 37, the temperature of the regenerator shell 37 can be reduced, even if the remaining fuel F inside the fuel piping 72 cannot be purged with an inert gas, thus reducing the likelihood of the fuel F inside the fuel piping 72 igniting. Once the combustion device 70 switches to low-combustion operation, the process returns to determining whether the temperature detected by the concentrated solution thermometer 53 exceeds a predetermined temperature (St12). If the temperature detected by the concentrated solution thermometer 53 does not exceed a predetermined temperature (NO in St12), the control device 60 estimates that the remaining fuel F is unlikely to ignite and stops the absorption chiller 1 (St15).

[0061] As shown in Figure 5, once the combustion device 70 is switched to low-combustion operation (St13), the control may be configured to stop the absorption chiller / heater 1 based on the subsequent time elapsed (St15). Figure 5 is a flowchart of the control of the operation of the absorption chiller / heater 1 showing the modified version. In this modified version, the flowchart shown in Figure 4 applies up to the step of switching the combustion device 70 to low-combustion operation (St13), so redundant explanations are omitted. In this modified version, once the combustion device 70 is switched to low-combustion operation (St13), the control device 60 determines whether a predetermined time has elapsed since switching to low-combustion operation (St14). The predetermined time is typically the time required for the absorbent liquid S flowing out of the regenerator 30 to decrease to the predetermined temperature mentioned above due to the low-combustion operation. If the predetermined time has not elapsed (NO in St14), the process returns to determining whether the predetermined time has elapsed (St14). On the other hand, if the predetermined time has elapsed (YES in St14), the absorption chiller / heater 1 is stopped (St15).

[0062] As explained above, with the absorption chiller / heater 1 according to this embodiment, even if a condition occurs during steady-state operation in which nitrogen N cannot be supplied, if a command to stop the absorption chiller / heater 1 has not been received, it can continue operating without stopping due to an error. In addition, a pre-alarm is issued in this state, so that relevant parties can be notified that a condition in which nitrogen N cannot be supplied has occurred, and the resolution of the nitrogen N supply failure can be encouraged. Furthermore, if a command to stop is received while a condition in which nitrogen N cannot be supplied is occurring during steady-state operation, the operation of the regenerator 30 is stopped while the absorbent liquid S in the regenerator 30 has not exceeded a predetermined temperature, thereby reducing the possibility of ignition of the remaining fuel F.

[0063] In the above description, the temperature-related value detector was assumed to be a concentrated solution thermometer 53 that detects the outlet temperature of the absorbent liquid S in the regenerator 30. However, it may also be a physical quantity that is related to the temperature of the absorbent liquid S in the regenerator 30 (i.e., correlated with the temperature of the absorbent liquid S). Examples of physical quantities related to the temperature of the absorbent liquid S in the regenerator 30 include the temperature of the exhaust gas generated when the fuel F is burned in the combustor 71, the pressure in the regenerator 30 (typically the pressure of the gas phase inside the regenerator shell 37), and the dew point temperature in the regenerator 30 (typically the dew point temperature of the gas phase inside the regenerator shell 37). In this case, the temperature-related value detector may be a thermometer that detects the temperature of the exhaust gas, a pressure gauge that detects the internal pressure of the regenerator 30, and a dew point thermometer that detects the dew point temperature inside the regenerator 30, respectively. In this case, the predetermined value detected by the temperature-related value detector should be a physical quantity that corresponds to the value detected by the temperature-related value detector when the temperature detected by the concentrated solution thermometer 53 reaches the predetermined temperature.

[0064] In the above explanation, the inert gas detector is described as a pressure switch 78 that turns on when the pressure drops below a predetermined level, but it may also be a pressure sensor. When a pressure sensor is used as the inert gas detector, if the pressure detected by the pressure sensor falls below the predetermined level, the control device 60 should take the same action as when the pressure switch 78 is turned on, such as issuing an alarm. In addition, the inert gas detector may use means other than pressure detection. For example, when an inert gas cylinder is used, a method for detecting the mass of the remaining gas may be used, or an external shortage signal may be input.

[0065] In the above explanation, the absorption cycle was assumed to be for single-effect absorption, but a high-temperature regenerator may be provided to make it double-effect or triple-effect or more. In this case, the combustion device 70 should be provided in the regenerator where the operating temperature is highest.

[0066] In the above description, the absorption chiller / heater 1 is assumed to be capable of both cooling and heating chilled / hot water, but it may also be a device that only cools or only heats. In other words, in this disclosure, the term "absorption chiller / heater" is used for convenience and does not necessarily require the ability to both cool and heat chilled / hot water; it is treated as a concept that includes absorption refrigerators and absorption heat pumps. [Explanation of symbols]

[0067] 1 Absorption chiller / heater 10 Absorbers 20 Evaporator 30 Regenerator 40 Condenser 53. Concentrated solution thermometer (temperature-related value detector) 60 Control device 70 Combustion device 71 Combustor 72 Fuel piping 76. Nitrogen piping (inert gas piping) 78. Pressure switch (inert gas detector) A air F fuel N Nitrogen (inert gas) S Absorbent Solution V Refrigerant

Claims

1. An absorption chiller / heater that transfers heat through a cycle of a refrigerant undergoing a phase change and an absorbent liquid mixed with the refrigerant, A regenerator having a combustor that burns a gaseous fuel mainly composed of hydrogen in order to generate heat for heating the absorbent liquid, A fuel pipe that guides the fuel to the combustor, An inert gas pipe for supplying an inert gas to the aforementioned fuel pipe, An inert gas detector for detecting whether or not the inert gas can be supplied to the fuel piping, The combustor comprises a control device for controlling the combustion operation of the combustor, The control device controls the combustion operation in the combustor so as to continue the combustion of the fuel in the combustor until it receives a command to stop the absorption chiller, when the inert gas detector detects that the inert gas cannot be supplied to the fuel piping while the fuel is burning in the combustor. Absorption chiller / heater.

2. The control device shall issue an alert if the inert gas detector detects that the inert gas cannot be supplied to the fuel piping while the fuel is burning in the combustor. The absorption chiller / heater according to claim 1.

3. The regenerator is equipped with a temperature-related value detector that detects the temperature of the absorbent liquid or a physical quantity related to that temperature, When the control device receives a command to stop the absorption chiller / heater while the inert gas detector has detected that the inert gas cannot be supplied to the fuel piping, and the value detected by the temperature-related value detector exceeds a predetermined value, the control device controls the combustion operation in the combustor to reduce the combustion rate in the combustor to a low combustion operation until the value detected by the temperature-related value detector falls below the predetermined value, and then stops the combustion of the fuel in the combustor. The absorption chiller / heater according to claim 1 or claim 2.

4. The regenerator is equipped with a temperature-related value detector that detects the temperature of the absorbent liquid or a physical quantity related to that temperature, When the control device receives a command to stop the absorption chiller / heater while the inert gas detector has detected that the inert gas cannot be supplied to the fuel piping, and the value detected by the temperature-related value detector exceeds a predetermined value, the control device controls the combustion operation in the combustor to perform a low-combustion operation with reduced combustion rate in the combustor for a predetermined period of time, and then stop the combustion of the fuel in the combustor. The absorption chiller / heater according to claim 1 or claim 2.

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