CN109253557B

CN109253557B - Absorption refrigerator

Info

Publication number: CN109253557B
Application number: CN201810698100.4A
Authority: CN
Inventors: 青山淳
Original assignee: Ebara Refrigeration Equipment and Systems Co Ltd
Current assignee: Ebara Refrigeration Equipment and Systems Co Ltd
Priority date: 2017-07-14
Filing date: 2018-06-29
Publication date: 2021-09-10
Anticipated expiration: 2038-06-29
Also published as: CN109253557A

Abstract

The invention provides an absorption refrigerator which can ensure necessary capacity and realize miniaturization. An absorption refrigerator (1) that cools or heats a fluid (C) to be temperature-regulated by an absorption cycle of an absorption liquid (S) and a refrigerant (V) configured by supplying a heat source (H) is provided with: a heat input amount adjusting device (33) that adjusts the amount of the heat source (H) supplied to the absorption refrigerator (1) per unit time; and a control device (60) that controls the heat input amount adjustment device (33). The control device (60) stores, as an upper limit value of the amount per unit time of the heat source (H) supplied to the absorption refrigerator (1), a rated upper limit value under rated conditions and an excessive upper limit value larger than the rated upper limit value, and controls the heat input amount adjusting device (33) within the range of the rated upper limit value at all times, and controls the heat input amount adjusting device (33) within the range of the excessive upper limit value when receiving an instruction to operate at an output larger than the rated output under rated conditions.

Description

Absorption refrigerator

Technical Field

The present invention relates to an absorption refrigerator, and more particularly, to an absorption refrigerator that can be miniaturized while securing a necessary capacity.

Background

An absorption refrigerator that cools cold water or heats hot water by an absorption cycle of an absorption liquid and a refrigerant can adjust the output by adjusting the heat input amount (the heating fluid introduction amount or the combustion amount) to a regenerator. Absorption chillers generally control the heat input so that the heat input to the regenerator does not exceed 100% of the rated value (see, for example, patent document 1). In addition, the absorption chiller is of a type that detects the temperature of cold water or hot water and controls the amount of heat input to the regenerator so that the detected temperature becomes a target temperature (see, for example, patent document 2).

Patent document 1: japanese patent No. 3630775

Patent document 2: japanese patent laid-open publication No. 2002-340429

In general, when the absorption chiller is operated at a rated 100%, the capacity is selected so as to be able to cope with the maximum heat load to be handled. However, the opportunity to handle the maximum heat load accounts for approximately 1% of the operating time, and the partial load operation accounts for the vast majority of the operating time. Since there are few opportunities, it cannot be said that it is efficient to select a capacity capable of handling the maximum heat load at the rated operation.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an absorption refrigerator that can be miniaturized while securing a necessary capacity.

In order to achieve the above object, for example, as shown in fig. 1, an absorption chiller according to a first aspect of the present invention cools or heats a fluid C to be temperature-adjusted through an absorption cycle of an absorption liquid S and a refrigerant V configured by supplying a heat source H, the absorption chiller 1 including: a heat input amount adjusting device 33 that adjusts the amount of the heat source H supplied to the absorption chiller 1 per unit time; and a control device 60 that controls the heat input amount adjusting device 33, the control device 60 being configured to: as the upper limit value of the amount per unit time of the heat source H supplied to the absorption chiller 1, a rated upper limit value under the rated condition and an excessive upper limit value larger than the rated upper limit value are stored, and the heat input amount adjusting device 33 is controlled within the range of the rated upper limit value at ordinary times, and when receiving an instruction to operate at an output larger than the rated output under the rated condition, the heat input amount adjusting device 33 is controlled within the range of the excessive upper limit value.

With this configuration, when the heat input amount adjusting device can be controlled within the range of the excessive upper limit value, the capacity capable of handling the maximum heat load is selected, and the absorption chiller can be downsized while securing the necessary capacity.

As shown in fig. 1, for example, an absorption chiller according to a second aspect of the present invention is an absorption chiller 1 according to the first aspect of the present invention, comprising: a regenerator 30 for heating the absorbent Sw having absorbed the refrigerant Ve by a heating source H to separate the refrigerant Vg from the absorbent Sw and generate a concentrated solution Sa having an increased concentration; an absorber 10 that absorbs the vapor Ve of the refrigerant by the absorption liquid Sa to generate a dilute solution Sw having a reduced concentration; and a dilute solution flow rate adjusting device 19 that directly or indirectly adjusts the flow rate of the dilute solution Sw flowing out from the absorber 10, wherein the absorption chiller 1 is configured to circulate the absorption liquids Sw and Sa through the regenerator 30 and the absorber 10, and the control device 60 controls the dilute solution flow rate adjusting device 19 so that the flow rate of the dilute solution Sw flowing out from the absorber 10 is increased as compared to the operation under the rated condition when receiving a command to operate at an output greater than the rated output.

With this configuration, when the operation is performed at an output higher than the rated output, the absorption liquid can be prevented from becoming excessively rich, and the increase in the internal pressure of the regenerator can be prevented, thereby preventing the operation from being unable to be continued.

As shown in fig. 1, for example, an absorption chiller according to a third aspect of the present invention is an absorption chiller 1 according to the first aspect of the present invention, comprising: a regenerator 30 for heating the absorbent Sw having absorbed the refrigerant Ve by a heating source H to separate the refrigerant Vg from the absorbent Sw and generate a concentrated solution Sa having an increased concentration; an absorber 10 that absorbs the vapor Ve of the refrigerant by the absorption liquid Sa to generate a dilute solution Sw having a reduced concentration; and a rich solution flow rate adjusting device 15 that directly or indirectly adjusts the flow rate of the rich solution Sa flowing out from the regenerator 30, wherein the absorption chiller 1 is configured to circulate the absorption liquids Sw and Sa through the regenerator 30 and the absorber 10, and the control device 60 controls the rich solution flow rate adjusting device 15 so that the flow rate of the rich solution Sa flowing out from the regenerator 30 is increased as compared with the operation under the rated condition when receiving a command to operate at an output greater than the rated output.

Further, for example, referring to fig. 1, in the absorption chiller 1 according to the fourth aspect of the present invention, in the absorption chiller 1 according to any one of the first to third aspects of the present invention, upon receiving a command to operate at an output greater than the rated output, the control device 60 changes the target value of the temperature-adjusting target fluid C flowing out of the absorption chiller 1 in a direction in which the difference between the target value and the temperature of the temperature-adjusting target fluid C introduced into the absorption chiller 1 decreases.

With this configuration, when the operation is performed at an output higher than the rated output, the absorption liquid can be prevented from becoming excessively rich, and the operation can be prevented from being unable to be continued.

For example, as shown in fig. 1, an absorption chiller according to a fifth aspect of the present invention is the absorption chiller 1 according to any one of the first to fourth aspects of the present invention described above, further comprising a condenser 40 for introducing vapor Vg of the refrigerant desorbed from the regenerator 30 and cooling and condensing the vapor Vg of the refrigerant with cooling water D to generate a refrigerant liquid Vf, wherein the regenerator 30 heats the absorbing liquid Sw of the absorbing refrigerant Ve with a heating source H to desorb the refrigerant Vg from the absorbing liquid Sw to generate a concentrated solution Sa having an increased concentration, and the control device 60 controls a cooling water flow rate adjustment device 91 for adjusting the flow rate of the cooling water D so that the flow rate of the cooling water D introduced into the condenser 40 is increased as compared with the case of operation under the rated condition when receiving an instruction to operate at an output greater than the rated output.

For example, referring to fig. 1, in the absorption chiller according to the sixth aspect of the present invention, in addition to the absorption chiller 1 according to the fifth aspect of the present invention, when receiving a command to operate at an output higher than the rated output, the control device 60 controls the cooling water temperature adjusting device 93 that adjusts the temperature of the cooling water D so that the temperature of the cooling water D introduced into the condenser 40 is lower than that during operation under the rated condition.

For example, as shown in fig. 1, an absorption chiller according to a seventh aspect of the present invention is the absorption chiller 1 according to any one of the first to fourth aspects of the present invention described above, further comprising a condenser 40 for introducing vapor Vg of the refrigerant desorbed from the regenerator 30 and cooling and condensing the vapor Vg of the refrigerant with cooling water D to generate a refrigerant liquid Vf, wherein the regenerator 30 heats the absorbing liquid Sw after absorbing the refrigerant Ve with a heating source H to desorb the refrigerant Vg from the absorbing liquid Sw to generate a concentrated solution Sa whose concentration increases, and the control device 60 controls a cooling water temperature adjusting device 93 for adjusting the temperature of the cooling water D so that the temperature of the cooling water D introduced into the condenser 40 is lower than that during operation under a rated condition when receiving an instruction to operate at an output greater than a rated output.

Further, for example, referring to fig. 1, an absorption chiller according to an eighth aspect of the present invention is the absorption chiller 1 according to any one of the first to seventh aspects of the present invention, wherein the control device 60 is configured to: the heat input amount adjusting device 33 is controlled within the range of the rated upper limit value when the command to operate at an output larger than the rated output disappears, when a predetermined time has elapsed since the command to operate at an output larger than the rated output was received, or when the time during which the command to operate at an output larger than the rated output was received cumulatively exceeds a predetermined cumulative time.

With this configuration, the operation at an output higher than the rated output, which is lower in efficiency than the operation at the rated output, is suppressed for a predetermined time or a predetermined cumulative time, and therefore, the decrease in efficiency can be suppressed.

An absorption chiller according to a ninth aspect of the present invention is an absorption chiller 1 according to any one of the first to eighth aspects of the present invention, for example, as shown in fig. 1, and includes: a temperature-adjustment-target-fluid-temperature detecting unit 54 that detects the temperature of the temperature adjustment target fluid C at the reference position; monitoring physical

quantity detection units

16, 25, 45, 51, 53, and 55 that detect one or more physical quantities to be monitored in order to perform appropriate operation of the absorption chiller 1; and a safety control means 65 that stops the operation of the absorption chiller 1 or limits the amount of the heat source H supplied to the absorption chiller 1 per unit time to a predetermined amount when the value detected by the monitoring physical

quantity detection units

16, 25, 45, 51, 53, and 55 exceeds an allowable upper limit value, and the control device 60 calculates: the amount per unit time of the heat source H to be introduced when the temperature detected by the temperature-adjustment target fluid temperature detection unit 54 is a preset temperature and the amount per unit time of the heat source H to be introduced when the value detected by the monitoring physical

quantity detection units

16, 25, 45, 51, 53, and 55 reaches the upper limit value set in the safety control unit 65 are controlled so that the minimum amount of the calculated amount per unit time of the heat source H is introduced into the absorption chiller 1.

Conventionally, in order to avoid crystallization of the absorption liquid when the concentration of the absorption liquid in the absorption cycle is higher than a predetermined value, there are cases where the operation is stopped or a safety device for limiting the amount of heat input to the regenerator is operated, but in general, there is a fresh operation exceeding the rated capacity such that the concentration of the absorption liquid is higher than the predetermined value. However, if the capacity is not exhibited easily due to contamination of heat transfer tubes or the like by the inclusion of non-condensable gas in the plant, there is a possibility that the safety device may not be operated continuously even if the safety device is operated at a capacity lower than the rated capacity.

With this configuration, the absorption chiller can be continuously operated by controlling the value detected by the monitored physical quantity detection unit to be equal to or less than the allowable upper limit value.

In order to provide an absorption chiller capable of continuous operation, for example, as shown in fig. 1, an absorption chiller according to a tenth aspect of the present invention cools or heats a fluid C to be temperature-adjusted by an absorption cycle of an absorption liquid S and a refrigerant V configured by supplying a heat source H, the absorption chiller 1 including: a heat input amount adjusting device 33 that adjusts the amount of the heat source H supplied to the absorption chiller 1 per unit time; a temperature-adjustment-target-fluid-temperature detecting unit 54 that detects the temperature of the temperature adjustment target fluid C at the reference position; monitoring physical

quantity detection units

16, 25, 45, 51, 53, and 55 that detect one or more physical quantities to be monitored in order to perform appropriate operation of the absorption chiller 1; a safety control means 65 that stops the operation of the absorption chiller 1 or limits the amount of the heat source H supplied to the absorption chiller 1 per unit time to a predetermined amount when the value detected by the monitoring physical

quantity detection unit

16, 25, 45, 51, 53, 55 exceeds an allowable upper limit value; and a control device 60 that calculates: the amount per unit time of the heat source H to be introduced when the temperature detected by the temperature-adjustment target fluid temperature detection unit 54 is a preset temperature and the amount per unit time of the heat source H to be introduced when the value detected by the monitoring physical

quantity detection units

In addition, for example, as shown in fig. 1, in the absorption chiller according to the eleventh aspect of the present invention, in addition to the absorption chiller 1 according to the ninth or tenth aspect of the present invention, the physical quantity detected by the monitoring physical

quantity detection units

51 and 53 is configured to include at least one of the temperature of the absorption liquid Sa and the concentration of the absorption liquid Sa.

With this configuration, the absorption refrigerator can be continuously operated while avoiding crystallization of the absorption liquid.

An absorption chiller according to a twelfth aspect of the present invention is, for example, as shown in fig. 1, and further includes, in addition to the absorption chiller 1 according to any one of the ninth through eleventh aspects of the present invention,: a regenerator 30 for heating the absorbent Sw having absorbed the refrigerant Ve by a heating source H to separate the refrigerant Vg from the absorbent Sw and generate a concentrated solution Sa having an increased concentration; and an absorber 10 that generates a dilute solution Sw having a decreased concentration by absorbing the vapor Ve of the refrigerant with the absorption liquid Sa, wherein the physical quantity detected by the monitoring physical quantity detecting unit 55 includes: at least one of the internal pressure of the regenerator 30 or a physical quantity related to the internal pressure of the regenerator 30, and the internal pressure of the absorber 10 or a physical quantity related to the internal pressure of the absorber 10.

With this configuration, it is possible to avoid an excessive increase in the internal pressure of the absorption refrigerator, and to continue the operation of the absorption refrigerator.

An absorption chiller according to a thirteenth aspect of the present invention is the absorption chiller 1 according to any one of the ninth through twelfth aspects of the present invention, for example, as shown in fig. 1, further comprising refrigerant

liquid reservoirs

23, 43 for storing refrigerant liquid Vf, which is a liquid of the refrigerant V, and the physical quantity detected by the monitoring

physical quantity detectors

25, 45 is configured to include a level of the refrigerant liquid Vf stored in the refrigerant

liquid reservoirs

23, 43.

With this configuration, the concentration of the absorbing liquid can be estimated, and crystallization of the absorbing liquid can be suppressed.

Further, for example, as shown in fig. 1, an absorption chiller according to a fourteenth aspect of the present invention is the absorption chiller 1 according to any one of the ninth to thirteenth aspects of the present invention, which includes an absorption liquid storage unit 13 that stores the absorption liquid Sw, and the physical quantity detected by the monitoring physical quantity detecting unit 16 is configured to include the liquid level of the absorption liquid Sw stored in the absorption liquid storage unit 13.

According to the present invention, when the heat input amount adjusting device is controlled within the range of the excessive upper limit value, the capacity capable of handling the maximum heat load is selected, and the absorption chiller can be downsized while securing the necessary capacity.

Drawings

Fig. 1 is a schematic system diagram of an absorption refrigerator according to an embodiment of the present invention.

Fig. 2 is a flowchart for explaining control to avoid as much as possible the stop of the absorption chiller based on the instruction of the safety control unit.

Fig. 3 is a timing chart for explaining control to avoid as much as possible the stop of the absorption chiller in response to a command from the safety control unit.

Description of reference numerals: 1 … absorption refrigerator; 10 … absorber; 15 … concentrated solution regulating valve; 19 … solution pump; 25 … evaporator refrigerant level gauge; 30 … regenerator; 33 … heating source regulating valve; a 40 … condenser; 45 … condenser refrigerant level gauge; 51 … concentrated solution thermometer; 53 … concentrated solution concentration meter; 54 … cold water thermometer; 55 … regenerator pressure gauge; 60 … control device; 65 … a safety control part; 91 … cooling water pump; 93 … cooling tower; c … Cold Water; d … cooling water; h … heat source; s … absorbing liquid; concentrated solution Sa …; sw … absorbent solution; v … refrigerant; ve … evaporator refrigerant vapor; vf … refrigerant liquid; vg … regenerator refrigerant vapor

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or similar reference numerals are given to the same or corresponding components, and redundant description is omitted.

In the present specification, an "absorption chiller" is a generic term for an absorption heat source unit that forms an absorption cycle by a regenerator, a condenser, an absorber, an evaporator, and the like by supplying a heating source to the regenerator, and cools or heats a fluid to be temperature-adjusted, and includes: the absorption refrigeration system includes an absorption refrigeration machine as a machine that supplies a heat source to a regenerator to form an absorption refrigeration cycle and supplies cold water (cooled temperature adjustment target fluid), an absorption cold/hot water machine as a machine that supplies a heat source to a regenerator to form an absorption cycle and supplies cold water (cooled temperature adjustment target fluid) and/or hot water (heated temperature adjustment target fluid), and a mechanical absorption heat pump as a machine that supplies at least temperature adjustment target fluid heated by an absorber by supplying a heat source to a regenerator to form an absorption heat pump cycle and recovering heat from the heat source water by an evaporator. Hereinafter, an absorption refrigerator as one embodiment will be described.

First, an absorption chiller 1 according to an embodiment of the present invention will be described with reference to fig. 1. Fig. 1 is a schematic system diagram of an absorption refrigerator 1. The absorption chiller 1 includes an absorber 10, an evaporator 20, a regenerator 30, and a condenser 40 as main constituent devices for performing an absorption refrigeration cycle, and further includes a control device 60. The absorption refrigerator 1 is a device that circulates a refrigerant V while changing its phase with respect to an absorption liquid S, and performs heat transfer to lower the temperature of cold water C as a fluid to be temperature-adjusted. In the following description, the absorption liquid is referred to as "dilute solution Sw" or "concentrated solution Sa" depending on the properties and the position on the absorption refrigeration cycle so as to facilitate the distinction in the absorption refrigeration cycle, but is collectively referred to as "absorption liquid S" regardless of the properties and the like. The refrigerant is referred to as "evaporator refrigerant vapor Ve", "regenerator refrigerant vapor Vg", and "refrigerant liquid Vf" depending on the properties and the position on the absorption refrigeration cycle so as to facilitate the distinction in the absorption refrigeration cycle, but is generally referred to as "refrigerant V" regardless of the properties and the like. In the present embodiment, an aqueous LiBr solution is used as the absorbent S (mixture of the absorbent and the refrigerant), and water (H) is used₂O) as the refrigerant V, but is not limited thereto, and a combination of other refrigerants and solutions (absorbents) may be used.

The absorber 10 is a device that absorbs the evaporator refrigerant vapor Ve generated in the evaporator 20 with the rich solution Sa. The absorber 10 has, inside an absorber tank 17: a cooling pipe 11 as a cooling water flow path through which the cooling water D flows, and a concentrated solution distribution nozzle 12 for distributing the concentrated solution Sa toward the outer surface of the cooling pipe 11. The rich solution distribution nozzle 12 is disposed above the cooling pipe 11 so that the distributed rich solution Sa falls on the cooling pipe 11. The absorber 10 is configured to absorb the evaporator refrigerant vapor Ve with the dispersed rich solution Sa, store the lean solution Sw having a decreased concentration in the storage portion 13 at the lower portion of the absorber tank 17, and deprive the rich solution Sa of absorption heat generated when the evaporator refrigerant vapor Ve is absorbed with the cooling water D. The absorber 10 has a dilute solution level meter 16 that detects the level of the dilute solution Sw in the storage section 13.

The evaporator 20 is a device that cools the cold water C by evaporating the refrigerant liquid Vf using the heat of the cold water C to generate evaporator refrigerant vapor Ve. The evaporator 20 includes, inside an evaporator tank 27: an evaporation pipe 21 as a cold water flow path through which cold water C flows, and a refrigerant liquid distribution nozzle 22 for distributing refrigerant liquid Vf toward the outer surface of the evaporation pipe 21. The refrigerant liquid distribution nozzle 22 is disposed above the evaporation tube 21 so that the distributed refrigerant liquid Vf falls on the evaporation tube 21. The evaporator 20 has: a refrigerant liquid pipe 28 for guiding the refrigerant liquid Vf stored in the storage portion 23 at the lower portion of the evaporator tank 27 to the refrigerant liquid distribution nozzle 22; and a refrigerant pump 29 that sends the refrigerant liquid Vf in the refrigerant liquid pipe 28 to the refrigerant liquid distribution nozzle 22. The evaporator 20 further includes an evaporator refrigerant level meter 25 that detects the level of the refrigerant liquid Vf in the reservoir 23. The evaporator 20 is configured to cool the cold water C by depriving the cold water C flowing in the evaporation tube 21 of the refrigerant liquid Vf dispersed to the outer surface of the evaporation tube 21 to evaporate and turn into vaporization heat of the evaporator refrigerant vapor Ve, and to store the refrigerant liquid Vf that is not evaporated among the dispersed refrigerant liquid Vf in the storage portion 23 of the evaporator tank 27.

In the present embodiment, the absorber 10 is disposed adjacent to the evaporator 20, and the upper portion of the absorber tank 17 communicates with the upper portion of the evaporator tank 27. With this configuration, the evaporator refrigerant vapor Ve generated inside the evaporator tank 27 can be guided to the inside of the absorber tank 17. A cooling water inlet pipe 11a for introducing cooling water D is connected to one end of the cooling pipe 11. A cooling water communication pipe 58 is connected to the other end of the cooling pipe 11. A cooling water supply pipe 98 outside the absorption refrigerator 1 is connected to the cooling water inlet pipe 11 a. The cooling water supply pipe 98 is connected to a cooling tower 93 outside the absorption refrigerator 1. The cooling tower 93 is configured such that the rotational speed of the fan is variable, and the temperature of the cooling water D can be changed by appropriately changing the rotational speed of the fan. The cooling tower 93 corresponds to a cooling water temperature adjusting device. A cooling water pump 91 outside the absorption refrigerator 1 is disposed in the cooling water supply pipe 98. The cooling water pump 91 is configured to have a variable rotation speed, and the flow rate of the discharged cooling water D can be changed by appropriately changing the rotation speed. The cooling water pump 91 corresponds to a cooling water flow rate adjusting device. The absorption refrigerator 1 is configured to cause the cooling water D to flow through the cooling pipe 11 by the operation of the cooling water pump 91. A cold water inlet pipe 21a for introducing cold water C is connected to one end of the evaporation pipe 21, and a cold water outlet pipe 21b for discharging cold water C is connected to the other end. In the present embodiment, a cold water thermometer 54 as a temperature detection unit of the fluid to be temperature-adjusted is provided in the cold water outlet pipe 21 b. That is, in the present embodiment, the outlet of the absorption refrigerator 1 is the reference position. A cold water return pipe 95 outside the absorption refrigerator 1 is connected to the cold water inlet pipe 21 a. A cold water pump 92 outside the absorption refrigerator 1 is disposed in the cold water return pipe 95. The absorption refrigerator 1 is configured to cause cold water C to flow through the evaporation tube 21 by the operation of the cold water pump 92. A cold water outgoing line 96 outside the absorption refrigerator 1 is connected to the cold water outlet pipe 21 b.

The regenerator 30 is a device that introduces and heats the dilute solution Sw, thereby separating the refrigerant V from the dilute solution Sw to generate the concentrated solution Sa. In the regenerator 30, the refrigerant V desorbed from the dilute solution Sw is in a vapor state, and the vapor of the refrigerant V is referred to as regenerator refrigerant vapor Vg. The regenerator 30 has: a heating unit 31 for heating the dilute solution Sw, and a regenerator tank 37 for storing the introduced absorbent S. The heating unit 31 is disposed inside the regenerator tank 37. The heating unit 31 is typically configured to heat the absorbent S by combustion heat of a burner or heat of steam, hot water, or the like introduced from the outside. A heat source fluid pipe 32 through which a heat source fluid H serving as a heat source flows is connected to the heating unit 31. The heating source fluid H typically uses a fuel fluid such as gas or oil when the heating portion 31 generates combustion heat of the burner, and uses a heating fluid such as steam or hot water when the heating portion 31 releases heat retained by the fluid introduced from the outside. The heat-source fluid pipe 32 is provided with a heat-source adjustment valve 33 that adjusts the flow rate of the heat-source fluid H flowing into the heating unit 31. The heating source adjustment valve 33 corresponds to a heat input amount adjustment device. The regenerator 30 is provided with a regenerator pressure gauge 55 for detecting the pressure of the gas phase portion inside the regenerator tank 37. A dilute solution pipe 18 for introducing the dilute solution Sw is connected to the bottom of the regenerator tank 37, and a concentrated solution pipe 38 for discharging the generated concentrated solution Sa is connected to the upper side. The regenerator 30 is configured to: the dilute solution Sw flowing in from the bottom of the regenerator tank 37 is heated by the heating unit 31, gradually concentrated to become the concentrated solution Sa while increasing the temperature, and the concentrated solution Sa reaching the liquid level of the concentrated solution pipe 38 flows out from the regenerator tank 37. As the regenerator 30, a cross-flow type regenerator, a flue-pipe type regenerator, a liquid-pipe type regenerator, or the like can be used.

The condenser 40 is a device that generates the refrigerant liquid Vf to be sent to the evaporator 20 by introducing the regenerator refrigerant vapor Vg evaporated from the lean solution Sw in the regenerator 30, cooling the vapor, and condensing the vapor. The condenser 40 has a condenser tube 41 as a member forming a flow path of the cooling water D inside a condenser tank 47. The condenser 40 is configured to store the generated refrigerant liquid Vf in the storage portion 43 at the lower portion of the condenser tank 47. The condenser 40 has a condenser refrigerant level gauge 45 that detects the level of the refrigerant liquid Vf in the reservoir 43. One end of the condensation duct 41 is connected to the other end of the cooling water communication tube 58 having one end connected to the cooling tube 11. A cooling water outlet pipe 41b for allowing the cooling water D to flow out is connected to the other end of the condensation pipe 41. A cooling water return pipe 99 outside the absorption refrigerator 1 is connected to the cooling water outlet pipe 41 b. The cooling water return pipe 99 is connected to the cooling tower 93 outside the absorption refrigerator 1. With this configuration, the cooling water D flowing through the cooling water return pipe 99 is cooled by the cooling tower 93 and supplied to the cooling water supply pipe 98.

The condenser tank 47 is disposed close to the regenerator tank 37. In the present embodiment, the upper portion of the regenerator tank 37 and the upper portion of the condenser tank 47 communicate with each other through the regenerator refrigerant vapor flow path 35. The condenser 40 is configured to introduce the regenerator refrigerant vapor Vg from the regenerator 30 through the regenerator refrigerant vapor flow path 35, deprive the cooling water D flowing through the condensation pipe 41 of heat of the regenerator refrigerant vapor Vg, and condense the regenerator refrigerant vapor Vg into the refrigerant liquid Vf. In the present embodiment, the condenser tank 47 and the regenerator tank 37 are disposed above the evaporator tank 27 and the absorber tank 17. The reservoir 43 of the condenser tank 47 and the evaporator tank 27 are configured such that: the refrigerant liquid Vf in the condenser tank 47 can be guided into the evaporator tank 27 by the potential head and the difference between the internal pressures of the reservoir 43 and the evaporator tank 27, connected by the condensed refrigerant liquid pipe 48.

The storage section 13 of the absorber tank 17 and the regenerator tank 37 are connected by a dilute solution pipe 18. A solution pump 19 is provided in the dilute solution pipe 18. The solution pump 19 is constituted by: the rotation speed is variable, and the flow rate of the discharged dilute solution Sw can be changed by appropriately changing the rotation speed. The solution pump 19 capable of changing the flow rate of the discharged dilute solution Sw corresponds to a dilute solution flow rate adjusting means. The absorption refrigerator 1 is configured to be able to convey the dilute solution Sw in the absorber tank 17 into the regenerator tank 37 by the solution pump 19. In the regenerator tank 37, the introduced lean solution Sw moves from the inlet to the outlet, and the refrigerant V is separated from the lean solution Sw, so that the concentration of the lean solution Sw increases.

The portion of the regenerator tank 37 from which the rich solution Sa flows and the rich solution distribution nozzle 12 of the absorber 10 are connected by a rich solution pipe 38. The absorption refrigerator 1 is configured to: the dilute solution Sw is conveyed to the regenerator tank 37 by the solution pump 19, and the concentrated solution Sa generated by the refrigerant V escaping from the regenerator tank 37 is introduced into the concentrated solution distribution nozzle 12 through the concentrated solution pipe 38. That is, the solution pump 19 can circulate the absorption liquid S between the absorber 10 and the regenerator 30. The concentrated solution pipe 38 is provided with: a concentrated solution adjusting valve 15 that adjusts the flow rate of the concentrated solution Sa introduced into the concentrated solution distribution nozzle 12; a concentrated solution thermometer 51 that detects the temperature of the concentrated solution Sa at the outlet of the regenerator 30; and a rich solution concentration meter 53 that detects the concentration of the rich solution Sa at the outlet of the regenerator 30. The concentrated solution adjusting valve 15 corresponds to a concentrated solution flow rate adjusting means. A solution heat exchanger 81 is inserted into the dilute solution pipe 18 and the concentrated solution pipe 38, and the solution heat exchanger 81 exchanges heat between the dilute solution Sw flowing through the dilute solution pipe 18 and the concentrated solution Sa flowing through the concentrated solution pipe 38.

The control device 60 is a device for controlling the operation of the absorption refrigerator 1. The controller 60 is electrically connected to the solution pump 19, the refrigerant pump 29, the cooling water pump 91, the cold water pump 92, and the cooling tower 93 by wires or wirelessly, and can control the start and stop of these components. Further, the controller 60 is configured to: the dilute solution level gauge 16, the evaporator refrigerant level gauge 25, and the condenser refrigerant level gauge 45 are electrically connected by wire or wirelessly, respectively, and the detected liquid levels can be received as signals. The controller 60 is electrically connected to the concentrated solution thermometer 51 and the cold water thermometer 54 by wire or wirelessly, and can receive the detected temperatures as signals. The control device 60 is connected to the rich solution concentration meter 53 by wire or radio, and can receive the detected concentration as a signal. The controller 60 is electrically connected to the regenerator pressure gauge 55 by wire or wirelessly, and can receive the detected pressure as a signal.

The controller 60 is electrically connected to the concentrated solution control valve 15 and the heat source control valve 33 by wire or wirelessly, and is configured to be able to control the opening degrees of these valves. In the control device 60, two upper limit values, namely, a rated upper limit value and an excessive upper limit value, are stored with respect to the flow rate of the heating source fluid H supplied to the heating unit 31. The rated upper limit value is an upper limit value of the heating source fluid H supplied to the heating portion 31 when the absorption refrigerator 1 is operated under rated conditions, and is typically a flow rate at 100% of the rated value. The rated condition is a condition for appropriately operating the absorption chiller 1, which is appropriately determined according to the specification of the absorption chiller 1. The rated 100% operation is the most efficient operation. The excessive upper limit value is an upper limit value of the heating source fluid H supplied to the heating portion 31 when the absorption chiller 1 is operated at an output greater than the rated output, and is a value greater than the rated upper limit value. In general, when the absorption chiller 1 is operated at an output greater than the rated output, the efficiency is reduced as compared with the operation under the rated condition, but it is effective when a large output is temporarily required due to an increase in the thermal load or the like. If the amount of heat generated by the heating unit 31 is increased in order to operate at an output greater than the rated output, there is a possibility that, for example, the appropriate operation of the absorption refrigerator 1 is inhibited by concentration of the absorption liquid S, and therefore, the upper limit value (the excessive upper limit value) of the flow rate of the heating source fluid H supplied to the heating unit 31 is set. In this way, the absorption chiller 1 can be operated at an output greater than the rated output by operating within the range of the excessively large upper limit value, and therefore, although it is difficult to sufficiently handle the maximum heat load during operation at the rated upper limit value, the capacity that can be handled during operation at the excessively large upper limit value can be selected, and thus, it is possible to achieve downsizing (typically, downsizing of the external dimensions and/or installation area) as compared with the case where the capacity that can handle the maximum heat load during rated operation is selected, and it also contributes to reduction of the introduction cost. Since the operation at an output higher than the rated output suppresses the inhibition of the appropriate operation of the absorption chiller 1, it is preferable to limit the operation time per one operation and/or the cumulative operation time. The control device 60 controls the opening degree of the heat source adjusting valve 33 so that the flow rate of the heat source fluid H supplied to the heating part 31 falls within a range of a rated upper limit value or an excessive upper limit value.

In the present embodiment, the control device 60 includes a safety control unit 65. The safety control unit 65 monitors a specific physical quantity in order to appropriately operate the absorption chiller 1, and issues a command to stop the operation of the absorption chiller 1 when the monitored physical quantity exceeds an allowable upper limit value. In the present embodiment, the temperature of the absorbing liquid S, the concentration of the absorbing liquid S, the internal pressure of the regenerator 30, the liquid level of the storage unit 13 of the absorber 10, the liquid level of the storage unit 23 of the evaporator 20, and the liquid level of the storage unit 43 of the condenser 40 are used as the physical quantities monitored by the safety controller 65. In the present embodiment, the safety control unit 65 is generally distinguished from the control device 60 from the functional viewpoint, but the safety control unit 65 may be integrally formed in the control device 60, or the safety control unit 65 may be physically provided separately from the control device 60. The control device 60 including such a safety control unit 65 is configured to: the absorption chiller 1 can be controlled as described below in the operation of the absorption chiller 1.

With continued reference to fig. 1, the operation of the absorption refrigerator 1 will be described. First, the operation of the absorption chiller 1 during normal operation will be described. When the absorption chiller 1 is operating normally, the solution pump 19, the refrigerant pump 29, the cooling water pump 91, the cold water pump 92, and the cooling tower 93 are operated by commands from the control device 60. When the circulation of the refrigerant V side is observed, the regenerator refrigerant vapor Vg introduced from the regenerator 30 to the condenser 40 through the regenerator refrigerant vapor flow path 35 is cooled and condensed by the cooling water D flowing through the condensation pipe 41, becomes the refrigerant liquid Vf, and is stored in the storage portion 43 of the condenser tank 47. The cooling water D that has cooled the regenerator refrigerant vapor Vg increases in temperature, flows out from the cooling water return pipe 99, and is supplied to the cooling tower 93. The refrigerant liquid Vf in the condenser tank 47 is introduced into the evaporator tank 27 through the condensed refrigerant liquid pipe 48.

The refrigerant liquid Vf introduced from the condenser tank 47 into the evaporator tank 27 is mixed with the refrigerant liquid Vf sprayed from the refrigerant liquid spraying nozzle 22 and not evaporated, and is stored in the storage portion 23 of the evaporator tank 27. The refrigerant liquid Vf in the evaporator tank 27 flows in the refrigerant liquid pipe 28 and reaches the refrigerant liquid scattering nozzle 22 by the refrigerant pump 29. The refrigerant liquid Vf having reached the refrigerant liquid distribution nozzle 22 is distributed toward the evaporation tube 21, obtains the heat of the cold water C flowing through the evaporation tube 21, and is partially evaporated to become the evaporator refrigerant vapor Ve, which is introduced into the absorber tank 17. The temperature of the cold water C deprived of heat by the distributed refrigerant liquid Vf decreases, and the cold water C flows out of the cold water going pipe 96 and is supplied to a place where the cold water C is used, such as an air conditioner. The refrigerant liquid Vf that has been distributed from the refrigerant liquid distribution nozzle 22 and has not evaporated mixes with the refrigerant liquid Vf introduced from the condenser tank 47, and is stored in the storage portion 23 of the evaporator tank 27.

Next, when the circulation of the solution S side of the absorption refrigerator 1 is observed, the dilute solution Sw stored in the storage section 13 in the absorber tank 17 flows through the dilute solution pipe 18 by the solution pump 19, and is introduced into the regenerator tank 37 after the temperature thereof is raised in the solution heat exchanger 81. The dilute solution Sw introduced into the regenerator tank 37 is heated by the heating unit 31, and the refrigerant V is desorbed to become the concentrated solution Sa. On the other hand, the refrigerant V desorbed from the lean solution Sw is sent as the regenerator refrigerant vapor Vg through the regenerator refrigerant vapor flow path 35 into the condenser tank 47. The rich solution Sa generated in the regenerator tank 37 flows through the rich solution pipe 38, and reaches the rich solution distribution nozzle 12 after the temperature thereof is lowered by heat exchange with the lean solution Sw in the solution heat exchanger 81.

The rich solution Sa that has reached the rich solution distribution nozzle 12 is distributed toward the cooling pipe 11, absorbs the evaporator refrigerant vapor Ve introduced from the evaporator 20, and decreases in concentration to become a dilute solution Sw. In the absorber tank 17, absorption heat is generated when the rich solution Sa absorbs the evaporator refrigerant vapor Ve. The generated absorption heat is introduced from the cooling water outward passage 98 and removed by the cooling water D flowing through the cooling pipe 11. The cooling water D flowing through the cooling pipe 11 absorbs heat and increases in temperature, and flows out to the cooling water communication pipe 58 and is supplied to the condensation pipe 41 of the condenser 40. The dilute solution Sw generated in the absorber tank 17 is stored in the storage section 13 in the absorber tank 17.

During the operation of the absorption chiller 1 as described above, the controller 60 adjusts the opening degree of the heat source adjusting valve 33 within the range of the rated upper limit value so that the temperature detected by the cold water thermometer 54 becomes the set temperature on average, thereby adjusting the heating amount of the heating unit 31. When the opening degree of the heating source adjustment valve 33 is increased within the range of the rated upper limit, the flow rate of the heating source fluid H supplied to the heating unit 31 increases, the heating amount of the heating unit 31 increases, and the concentration of the concentrated solution Sa generated by the regenerator 30 increases. When the concentrated solution Sa having the increased concentration is transported to the absorber 10 and distributed, the flow rate of the evaporator refrigerant vapor Ve absorbed by the concentrated solution Sa increases, the amount of the evaporator refrigerant vapor Ve generated in the evaporator 20 increases, the amount of heat extracted from the cold water C increases, and as a result, the temperature of the cold water C decreases. Conversely, when the opening degree of the heating source adjustment valve 33 is decreased, the heating amount of the heating unit 31 decreases, the concentration of the concentrated solution Sa decreases, the flow rate of the evaporator refrigerant vapor Ve absorbed in the concentrated solution Sa decreases, and the amount of generation of the evaporator refrigerant vapor Ve decreases, and as a result, the amount of heat extracted from the cold water C decreases, and the temperature of the cold water C increases.

Further, during the operation of the absorption chiller 1 under the rated condition, the absorption chiller 1 may be required to operate at an output higher than the rated output due to an increase in the thermal load of the supply target of the cold water C, or the like. When receiving a command to operate at an output greater than the rated output, the control device 60 switches the adjustment of the opening degree of the heat source adjusting valve 33, which was performed so far within the range of the rated upper limit value, to the adjustment performed within the range of the excessively large upper limit value. If the opening degree of the heat source-adjusting valve 33 is adjusted within the range of the excessive upper limit value, the flow rate of the heat source fluid H supplied to the heating portion 31 can be increased as compared with the case of performing within the range of the rated upper limit value, and the amount of heat taken by the refrigerant V from the cold water C in the evaporator 20 can be increased, so that the operation can be performed with an output larger than the rated output. In the case where the absorption chiller 1 is operated at an output greater than the rated output, one or more of the following cases may be performed in a batch manner, in addition to increasing the opening degree of the heat source-source adjusting valve 33.

First, the control device 60 increases the circulation flow rate of the rich solution Sa by increasing the opening degree of the rich solution adjustment valve 15. When the circulation flow rate of the rich solution Sa is increased, the concentration of the rich solution Sa can be suppressed from becoming excessively rich, and the pressure rise in the regenerator tank 37 can be suppressed. In addition, when the circulation flow rate of the rich solution Sa is increased, the flow rate of the absorption liquid S flowing into the absorber 10 is increased, and therefore, in order to stabilize the liquid level of the reservoir portion 13 of the absorber tank 17, it is preferable to increase the flow rate of the lean solution Sw flowing out from the absorber 10.

Second, the control device 60 increases the rotation speed of the solution pump 19 to increase the flow rate of the dilute solution Sw transferred from the absorber 10 to the regenerator 30. When the flow rate of the dilute solution Sw is increased, the concentration of the absorbent S can be suppressed from becoming excessively rich, and the pressure increase in the regenerator tank 37 can be suppressed. Further, when the flow rate of the lean solution Sw sent from the absorber 10 to the regenerator 30 increases, the rate of increase in the liquid level of the absorption liquid S in the regenerator tank 37 also increases, and therefore the flow rate of the rich solution Sa flowing out of the regenerator tank 37 increases, and as a result, the circulation flow rate of the rich solution Sa increases.

Third, the control device 60 makes the target value of the temperature detected by the cold water thermometer 54 higher than the set temperature. That is, the set value of the outlet temperature of the cold water C is changed so that the difference between the inlet temperature and the outlet temperature of the cold water C with respect to the evaporator 20 is reduced. Typically, the amount of change in the set temperature is about 0.3 to 0.5 ℃. If the target value of the temperature detected by the cold water thermometer 54 is higher than the set temperature, the concentration of the absorbent S can be suppressed from becoming excessively rich.

Fourth, the controller 60 increases the rotation speed of the cooling water pump 91 to increase the flow rate of the cooling water D supplied to the absorber 10 and the condenser 40. When the flow rate of the cooling water D is increased, the amounts of the absorption heat of the absorber 10 and the condensation heat of the condenser 40 can be increased, and the absorption refrigeration cycle of the absorption liquid S and the refrigerant V can be appropriately performed, and the concentration of the absorption liquid S can be suppressed from becoming excessively high.

Fifth, the controller 60 increases the rotation speed of the fan of the cooling tower 93 to lower the temperature of the cooling water D supplied to the absorber 10 and the condenser 40. When the temperature of the cooling water D is lowered, the amounts of the absorption heat of the absorber 10 and the condensation heat of the condenser 40 can be increased, and the absorption refrigeration cycle of the absorption liquid S and the refrigerant V can be appropriately performed, and the concentration of the absorption liquid S can be suppressed from becoming excessively high.

In addition, in order to request the absorption chiller 1 to operate at an output greater than the rated output, the concentration of the absorption liquid S can be promoted when the opening degree of the heat source-adjusting valve 33 is increased to increase the heating amount of the heating unit 31, and therefore, even when the first to fifth measures are taken, it may be difficult to continue the absorption chiller 1 to operate properly. As important factors that make it difficult to continue the proper operation of the absorption chiller 1, for example, the concentration of the absorption liquid S and/or the excessive increase in the temperature of the absorption liquid S to the extent that crystallization of the absorption liquid S occurs, the increase in the pressure of the portion where the pressure of the absorption chiller 1 becomes the highest, and the like can be cited. Alternatively, it may be difficult to continue the appropriate operation of the absorption refrigerator 1 due to the difficulty in exerting the capacity due to the inclusion of non-condensable gas into the equipment, contamination of the evaporation tube 21, or the like. In the present embodiment, in order to determine whether or not the appropriate operation of the absorption chiller 1 can be continued, a rich solution thermometer 51 that detects the temperature of the rich solution Sa at the outlet of the regenerator 30 where the concentration of the absorption liquid S becomes the highest, a rich solution concentration meter 53 that detects the concentration, a regenerator pressure gauge 55 that detects the internal pressure of the regenerator 30 where the pressure of the absorption chiller 1 becomes the highest, a lean solution level gauge 16 that detects the level of the lean solution Sw in the absorber tank 17, an evaporator refrigerant level gauge 25 that detects the level of the refrigerant liquid Vf in the absorption chiller 1, and a condenser refrigerant level gauge 45 are provided. Here, the rich solution thermometer 51, the rich solution concentration meter 53, the regenerator pressure gauge 55, the lean solution level meter 16, the evaporator refrigerant level meter 25, and the condenser refrigerant level meter 45 correspond to monitoring physical quantity detecting portions, respectively.

In the present embodiment, the safety control unit 65 determines whether or not the physical quantities detected by the respective monitored physical quantity detection units exceed the allowable upper limit value, and when one or more of the physical quantities detected by the respective monitored physical quantity detection units exceed the allowable upper limit value, the safety control unit 65 issues a command to stop the operation of the absorption chiller 1, and the control device 60 stops the absorption chiller 1, thereby protecting the absorption chiller 1. However, when the absorption chiller 1 is stopped, the supply of the chilled water C is also stopped, and the heat load to be supplied with the chilled water C cannot be handled at all, and therefore, it is preferable to avoid the stop of the absorption chiller 1 as much as possible. Therefore, in the present embodiment, the following control is performed.

Fig. 2 is a flowchart illustrating control for avoiding as much as possible the stop of the absorption chiller 1 in response to a command from the safety control unit 65. The controller 60 calculates the flow rate of the heat-source fluid H introduced into the heating portion 31 when the temperature detected by the cold water thermometer 54 is set to a preset temperature during the operation of the absorption chiller 1 (a heat-source fluid H flow rate calculation step based on a set value: S1). The controller 60 calculates the flow rate of the heat-source fluid H introduced into the heating unit 31 when the physical quantity detected by each monitoring physical quantity detector reaches the upper limit value (a heat-source fluid H flow rate calculation step in which each physical quantity reaches the upper limit value: S2). In addition, although fig. 2 shows that the heating source fluid H flow rate calculation step (S2) in which each physical quantity has the upper limit value is performed after the heating source fluid H flow rate calculation step (S1) based on the set value, the step (S1) may be performed after the step (S2) in reverse order, or the step (S1) and the step (S2) may be performed in parallel.

When the flow rate of the heat source fluid H based on the set value and the flow rate of the heat source fluid H at which each physical quantity becomes the upper limit value are calculated, the control device 60 adjusts the opening degree of the heat source adjusting valve 33 so that the heating source fluid H that is the smallest of the calculated flow rates of the heat source fluid H is introduced into the heating unit 31 (heat source adjusting valve 33 control step S3). By performing such control, the safety controller 65 can set the temperature of the cold water C to the set value without issuing a stop command for the absorption chiller 1 when the minimum flow rate of the heating source fluid H is the flow rate of the heating source fluid H based on the set value. Further, when the minimum heating source fluid H flow rate is the heating source fluid H flow rate at which any one of the physical quantities detected by the monitoring physical quantity detection portions has an upper limit value, the temperature of the chilled water C does not reach the set value, but the safety control portion 65 can avoid issuing a stop command for the absorption chiller 1 and continue the appropriate operation of the absorption chiller 1.

When the opening degree of the heat source adjusting valve 33 is adjusted (S3), the safety controller 65 determines whether any of the physical quantities detected by the monitored physical quantity detectors exceeds the upper limit value (S4). In the heat source regulating valve 33 controlling step (S3), the opening degree of the heat source regulating valve 33 is adjusted so that the physical quantity detected by each monitored physical quantity detecting unit does not exceed the upper limit value, but if the physical quantity exceeds the upper limit value in some cases, the judgment is made so that measures for protecting the absorption chiller 1 can be taken (S4). If the safety control unit 65 determines that any of the physical quantities exceeds the upper limit value, it issues a command to stop the absorption chiller 1 to the control device 60, and the control device 60 stops the absorption chiller 1 based on the command from the safety control unit 65 (S6). On the other hand, when any of the physical quantities does not exceed the upper limit value, the control device 60 determines whether or not there is a stop command for the absorption chiller 1 in the normal operation (S5). The stop during the normal operation is a stop of the absorption chiller 1 that can be performed in response to the cold water C usage side with a reduced heat load or the like in a state where the absorption chiller 1 can continue the operation. When there is a stop command during normal operation, the control device 60 stops the absorption chiller 1 (S6). On the other hand, if there is no stop command during the normal operation, the process returns to the step of calculating the flow rate of the heating source fluid H based on the set value (S1), and the above-described flow is repeated.

Fig. 3 is a timing chart showing an example of the above control. In fig. 3, the horizontal axis represents time, and the vertical axis represents the calculated flow rate of the heating source fluid H. In fig. 3, a solid line Lr indicates the flow rate of the heating source fluid H based on the set value, and a dashed dotted line Ls indicates the minimum flow rate among the flow rates of the heating source fluid H at which the physical quantity detected by each monitoring physical quantity detection unit has an upper limit value. In the example shown in fig. 3, until time t1, the solid line Lr is smaller than the dashed dotted line Ls, and therefore the control device 60 controls the opening degree of the heat-source-adjusting valve 33 so that the flow rate of the heat-source fluid H calculated based on the set value is introduced into the heating section 31. Since the dashed-dotted line Ls is smaller than the solid line Lr between time t1 and time t2, the control device 60 controls the opening degree of the heat source-adjusting valve 33 so that the flow rate of the heat source fluid H whose detected physical quantity is the upper limit value is introduced into the heating unit 31. Then, after time t2, since the solid line Lr is again smaller than the dashed-dotted line Ls, the control device 60 controls the opening degree of the heat-source adjusting valve 33 so that the flow rate of the heat-source fluid H calculated based on the set value is introduced into the heating section 31. In the example shown in fig. 3, at time t3, the control device 60 receives a stop command during normal operation, and therefore, the heating-source adjustment valve 33 is closed to the full close, thereby reducing the supply amount of the heating-source fluid H to the heating portion 31. In this way, the operation of the safety device is avoided and the temperature of the cold water C is brought as close as possible to the set value.

However, when receiving a command to operate at an output greater than the rated output and adjusting the opening degree of the heating source-adjusting valve 33 within a range exceeding the rated upper limit value and exceeding the excessive upper limit value, it is preferable to avoid the decrease in the efficiency of the absorption chiller 1 as much as possible. Therefore, in the present embodiment, when a predetermined time has elapsed since the instruction to operate at an output larger than the rated output was received, or when the cumulative total of the times at which the instruction to operate at an output larger than the rated output was received exceeds a predetermined cumulative time, the opening degree of the heat source adjusting valve 33 is adjusted to return to the range of the rated upper limit value. The predetermined cumulative time may be reset when a predetermined period (for example, 1 month, 1 year, or the like) has elapsed. This can prevent the absorption refrigerator 1 from operating with low efficiency for a long period of time. When the opening degree of the heat source adjusting valve 33 is adjusted within the range of the excessive upper limit value, if the command to operate at an output larger than the rated output is canceled, the opening degree of the heat source adjusting valve 33 is naturally adjusted back within the range of the rated upper limit value.

As described above, according to the absorption chiller 1 of the present embodiment, since it is possible to operate at an output higher than the rated output, it is possible to select a device having a capacity smaller than the maximum thermal load to be handled during rated operation, and it is possible to reduce the size of the absorption chiller 1. Further, when receiving a command to operate at an output greater than the rated output, the circulation flow rates of the rich solution Sa and the lean solution Sw are increased, so that the concentration of the absorbing liquid S can be suppressed from becoming excessively rich, and the pressure in the regenerator tank 37 can be suppressed from rising. When receiving a command to operate at an output greater than the rated output, the set value of the outlet temperature of the cold water C is changed so that the difference between the inlet temperature and the outlet temperature of the cold water C in the evaporator 20 is small, thereby increasing the flow rate of the cooling water D supplied to the absorber 10 and the condenser 40, decreasing the temperature of the cooling water D supplied to the absorber 10 and the condenser 40, and also contributing to suppressing the concentration of the absorbent S from becoming excessively rich. Further, when the opening degree of the heat source-adjusting valve 33 is adjusted so that the temperature of the cold water C flowing out of the absorption chiller 1 becomes a preset temperature and the physical quantity detected by each monitored physical quantity detecting unit exceeds the allowable upper limit value, the absorption chiller 1 can be continuously operated because the control is performed so that the physical quantity detected by each monitored physical quantity detecting unit becomes equal to or less than the allowable upper limit value in preference to the temperature adjustment of the cold water C.

In the above description, the internal pressure of the regenerator 30 is detected by the regenerator pressure gauge 55 as one of the physical quantities detected by the monitoring physical quantity detecting unit and monitored by the safety control unit 65, but instead, a physical quantity related to the internal pressure of the regenerator 30 may be detected. As the physical quantity related to the internal pressure of the regenerator 30, for example, the temperature of the regenerator refrigerant vapor Vg corresponding to the dew point temperature of the refrigerant V can be cited. In the case where the absorption chiller is a second type of absorption heat pump, the internal pressure of the absorber, which is the main component having the highest internal pressure, or a physical quantity related to the internal pressure of the absorber may be detected.

In the above description, the monitoring physical quantity detection portion includes the lean solution level meter 16, the evaporator refrigerant level meter 25, the condenser refrigerant level meter 45, the rich solution thermometer 51, the rich solution concentration meter 53, and the regenerator pressure gauge 55, but an unused detection portion may be omitted as long as at least one of these is provided.

In the above description, the safety control unit 65 transmits the instruction to stop the operation of the absorption chiller 1 to the control device 60 when the monitored physical quantity exceeds the allowable upper limit value, but may output an instruction to limit the flow rate of the heating source fluid H flowing into the heating unit 31 to a predetermined flow rate instead of outputting the instruction to stop the operation of the absorption chiller 1. The predetermined flow rate is the flow rate of the heating source fluid H that reduces the output to such an extent that the appropriate operation of the absorption chiller 1 can be reliably performed. When the physical quantity monitored by the safety control section 65 exceeds the allowable upper limit value and when a command for limiting the flow rate of the heating source fluid H flowing into the heating section 31 to a predetermined flow rate is output, in the step (S4) of determining whether or not any of the physical quantities detected by the monitored physical quantity detection units exceeds the upper limit value in the flowchart shown in fig. 2, if it is determined that any of the physical quantities exceeds the upper limit value, the process of stopping the absorption chiller 1 is not started (S6), and the control device 60 controls the opening degree of the heat source-source adjusting valve 33 so as to limit the flow rate of the heat source fluid H flowing into the heating part 31 to a predetermined flow rate based on the command received from the safety control part 65, and thereafter, the process returns to the step of determining whether any of the physical quantities detected by the monitored physical quantity detection units exceeds the upper limit value (S4).

In the above description, the heating source is the heating source fluid H, but the heating source may be a solid such as a solid fuel.

In the above description, the reference position is set as the outlet of the absorption chiller 1, and the cold water thermometer 54 (temperature-adjustment target fluid temperature detection unit) is provided in the cold water outlet pipe 21b, but the reference position may be set as the inlet of the absorption chiller 1, and the cold water thermometer 54 may be provided in the cold water inlet pipe 21 a. The temperature-adjusting fluid temperature detector may be a member that indirectly detects the temperature of the cold water C, instead of the cold water thermometer 54 that directly detects the temperature of the cold water C.

In the above description, the cooling water D is introduced into the absorber 11 and then introduced into the condenser 40, but may be introduced into the absorber 11 after being introduced into the condenser 40, or may be introduced into the absorber 10 and the condenser 40 in parallel.

In the above description, the cooling water pump 91 and the cold water pump 92 are not components of the absorption chiller 1, but the cooling water pump 91 and/or the cold water pump 92 may be provided as components of the absorption chiller 1. However, since the cooling water D flowing through the cooling water pump 91 and the cooling water C flowing through the cooling water pump 92 generally have different transport distances, flow rates, and the like to the supply target depending on conditions such as the location where the absorption chiller 1 is installed, it is preferable to be able to select the capacity of the absorption chiller 1 suitable for the installation location and the like without using the cooling water pump 91 and the cooling water pump 92 as components of the absorption chiller 1.

In the above description, the absorption chiller 1 is configured for single-effect use for ease of understanding, but may be applied to a multi-effect absorption chiller having a plurality of regenerators, or an absorption chiller having a plurality of evaporators/absorbers with different operating pressures.

In the above description, the absorption chiller is described as an absorption chiller, but may be another absorption heat source machine that performs an absorption cycle of the absorption liquid S and the refrigerant V, such as an absorption chiller, an absorption heat pump, or the like.

Claims

1. An absorption refrigerator that cools or heats a fluid to be temperature-adjusted by an absorption cycle of an absorption liquid and a refrigerant, the absorption refrigerator being configured by supplying a heat source, the absorption refrigerator comprising:

a heat input amount adjusting device that adjusts an amount per unit time of the heating source supplied to the absorption refrigerator; and

a control device that controls the heat input amount adjusting device,

the control device is configured to: the absorption chiller may further include a heat input amount adjusting device that is stored as an upper limit value of the amount per unit time of the heating source supplied to the absorption chiller, the heat input amount adjusting device being controlled within a range of the rated upper limit value, and the heat input amount adjusting device being controlled within a range of the excessive upper limit value when receiving a command to operate at an output larger than a rated output under the rated condition,

the control device, upon receiving a command to operate at an output greater than the rated output, changes the target value of the temperature of the fluid to be temperature-regulated flowing out of the absorption chiller to a direction in which the difference between the target value and the temperature of the fluid to be temperature-regulated introduced into the absorption chiller decreases.

2. The absorption chiller according to claim 1, comprising:

a regenerator that heats the absorbent having absorbed the refrigerant by the heating source, and separates the refrigerant from the absorbent to generate a concentrated solution having an increased concentration;

an absorber that absorbs the vapor of the refrigerant with the absorption liquid to generate a lean solution having a reduced concentration; and

a dilute solution flow rate adjusting device that directly or indirectly adjusts a flow rate of the dilute solution flowing out from the absorber,

the absorption refrigerator is configured to circulate the absorption liquid through the regenerator and the absorber,

the control device controls the dilute solution flow rate adjustment device so that the flow rate of the dilute solution flowing out of the absorber is increased in comparison with the operation under the rated condition when receiving a command to operate at an output greater than the rated output.

3. The absorption chiller according to claim 1, comprising:

a concentrated solution flow rate adjusting device that directly or indirectly adjusts a flow rate of the concentrated solution flowing out from the regenerator,

the control device, upon receiving a command to operate at an output greater than the rated output, controls the rich solution flow rate adjustment device so that the flow rate of the rich solution flowing out of the regenerator is increased as compared to the operation under the rated condition.

4. An absorption chiller according to any one of claims 1 to 3,

a condenser that generates a refrigerant liquid by introducing the vapor of the refrigerant desorbed from the regenerator and cooling and condensing the vapor of the refrigerant with cooling water, wherein the regenerator heats the absorbent having absorbed the refrigerant with the heating source to desorb the refrigerant from the absorbent to generate a concentrated solution having an increased concentration,

the control device controls the cooling water flow rate adjustment device that adjusts the flow rate of the cooling water so that the flow rate of the cooling water introduced into the condenser is increased as compared to the operation under the rated condition when receiving a command to operate at an output greater than the rated output.

5. An absorption chiller according to claim 4,

the control device controls a cooling water temperature adjusting device that adjusts the temperature of the cooling water so that the temperature of the cooling water introduced into the condenser is lower than during operation under the rated condition, when receiving a command that the operation should be performed at an output greater than the rated output.

6. An absorption chiller according to any one of claims 1 to 3,

7. An absorption chiller according to any one of claims 1 to 3,

the control device is configured to: the heat input amount adjusting device is controlled within the range of the rated upper limit value when a command to operate at an output larger than the rated output disappears, when a predetermined time has elapsed since a command to operate at an output larger than the rated output is received, or when a predetermined cumulative time has exceeded a cumulative time of times at which commands to operate at an output larger than the rated output are received.

8. An absorption refrigerator according to any one of claims 1 to 3, comprising:

a temperature-adjustment-target-fluid temperature detection unit that detects a temperature of the temperature adjustment target fluid at a reference position;

a monitored physical quantity detection unit that detects one or more physical quantities to be monitored in order to perform an appropriate operation of the absorption chiller; and

a safety control means for stopping the operation of the absorption chiller or limiting the amount of the heating source supplied to the absorption chiller per unit time to a predetermined amount when the value detected by the monitored physical quantity detection unit exceeds an allowable upper limit value,

the control device calculates: the heat input amount adjusting device may control the heat input amount adjusting device so as to introduce a minimum amount of the calculated amount of the heat source per unit time into the absorption chiller, the minimum amount of the heat source per unit time being an amount of the heat source per unit time to be introduced when the temperature detected by the temperature-adjustment-target fluid temperature detecting unit is a preset temperature, and the minimum amount of the heat source per unit time to be introduced when the value detected by the monitored physical quantity detecting unit becomes the upper limit value set in the safety control unit.