CN106895600B

CN106895600B - Absorption heat pump

Info

Publication number: CN106895600B
Application number: CN201611062956.XA
Authority: CN
Inventors: 竹村与四郎; 福住幸大; 山田宏幸
Original assignee: Ebara Refrigeration Equipment and Systems Co Ltd
Current assignee: Ebara Refrigeration Equipment and Systems Co Ltd
Priority date: 2015-12-01
Filing date: 2016-11-25
Publication date: 2020-07-24
Anticipated expiration: 2036-11-25
Also published as: CN106895600A; JP6337062B2; JP2017106707A

Abstract

The invention provides an absorption heat pump, which can restrain the pressure of a steam generating part from excessively rising without operating a safety valve. An absorption heat pump for generating vapor of a heating medium by absorbing heat of an introduced heat source fluid by an absorption heat pump cycle of an absorption liquid and a refrigerant, the absorption heat pump comprising: a steam generation unit that generates steam of a medium to be heated supplied to a desired object; a pressure detection unit that detects a pressure of the steam generation unit; a safety valve provided in the steam supply pipe or the steam generating part for allowing the steam of the medium to be heated generated in the steam generating part to flow out to the desired object; a steam discharge valve provided in the supply steam pipe or the steam generating section; and a control device for opening the vapor discharge valve when the pressure detected by the pressure detection unit exceeds the target pressure of the vapor generation unit and is equal to or higher than a first predetermined pressure lower than the pressure at which the safety valve opens.

Description

Absorption heat pump

Technical Field

The present invention relates to an absorption heat pump, and more particularly, to an absorption heat pump capable of suppressing an excessive pressure rise in a steam generating unit without operating a safety valve.

Background

As a heat source machine that takes out a heated medium having a temperature higher than the driving heat source temperature, there is a second absorption heat pump. The second absorption heat pump includes, as main components: an evaporator that evaporates a refrigerant liquid, an absorber that absorbs a refrigerant vapor with an absorbing liquid, a regenerator that separates a refrigerant from an absorbing liquid, and a condenser that condenses a refrigerant vapor. The second absorption heat pump can extract the high-utility medium vapor to be heated by supplying the low-temperature exhaust heat water having a relatively low utility value as the heat source medium to the regenerator and the evaporator. There is an absorption heat pump that controls at least one of the capacity of a regeneration unit, the capacity of a condensation unit, the capacity of an evaporation unit, and the capacity of an absorption unit so that the pressure of a generation unit that generates a heating medium vapor does not become too high and the pressure on the side to be heated does not exceed a predetermined pressure (see, for example, patent document 1).

Patent document 1: japanese laid-open patent publication No. 2006-207882

However, in the control described in patent document 1, the output suppression effect is indirect and cannot catch up with the pressure rise, and therefore the relief valve may operate.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an absorption heat pump capable of suppressing an excessive pressure rise in a steam generating unit without operating a safety valve.

In order to achieve the above object, an absorption heat pump according to a first aspect of the present invention is an absorption heat pump 1 that generates a vapor Wv of a medium to be heated by absorbing heat of an introduced heat source fluid h through an absorption heat pump cycle of an absorbent and a refrigerant, as shown in fig. 1, for example, the absorption heat pump 1 including: a steam generation unit 80 that generates steam Wv of the medium to be heated supplied to the demand target; a pressure detection unit 93 for detecting the pressure of the steam generation unit 80; a safety valve 88 provided in the supply steam pipe 89 or the steam generating portion 80, the supply steam pipe 89 allowing the steam Wv of the medium to be heated generated in the steam generating portion 80 to flow out toward the target; a vapor discharge valve 95 provided in the supply vapor pipe 89 or the vapor generation part 80; and a control device 90 for opening the vapor vent valve 95 by the vapor vent valve 95 when the pressure detected by the pressure detection unit 93 exceeds the target pressure of the vapor generation unit 80 and is equal to or higher than a first predetermined pressure which is lower than the pressure at which the relief valve 88 opens.

With this configuration, an excessive increase in pressure in the steam generating unit can be suppressed without operating the safety valve.

In addition, in the absorption heat pump according to the second aspect of the present invention, for example, referring to fig. 1, in the absorption heat pump 1 according to the first aspect of the present invention, the controller 90 controls the opening degree of the vapor vent valve 95 such that: the control device 90 gradually increases the opening degree of the vapor vent valve 95 when the pressure detected by the pressure detection unit 93 maintains a pressure equal to or higher than a first predetermined pressure, and the control device 90 gradually decreases the opening degree of the vapor vent valve 95 when the pressure detected by the pressure detection unit 93 exceeds a target pressure and maintains a pressure equal to or lower than a second predetermined pressure which is lower than the first predetermined pressure.

With this configuration, the amount of vapor discharged can be varied, and the generation of noise and white smoke accompanying the discharge of vapor can be suppressed, thereby reducing the influence on the surrounding environment.

In addition, as an absorption heat pump according to a third aspect of the present invention, for example, referring to fig. 1, in addition to the absorption heat pump 1 according to the second aspect of the present invention described above, the control device 90 controls the opening degree of the vapor vent valve 95 in such a manner that: the change speed of the opening degree of the vapor vent valve 95 when the opening degree of the vapor vent valve 95 is gradually reduced is slower than when the opening degree of the vapor vent valve 95 is gradually increased.

With this configuration, when the opening degree of the vapor vent valve is gradually increased, a rapid pressure rise can be suppressed, and when the opening degree of the vapor vent valve is gradually decreased, the normal operation in which the vapor vent valve is closed can be stably resumed.

In addition, as shown in fig. 1, for example, in the absorption heat pump 1 according to the fourth aspect of the present invention, in addition to the absorption heat pump 1 according to any one of the first to third aspects of the present invention, the control device 90 performs an output suppression measure for suppressing the output of the absorption heat pump 1 when the pressure detected by the pressure detection unit 93 exceeds the target pressure of the steam generation unit 80 and is equal to or higher than a third predetermined pressure that is lower than the pressure at which the relief valve 88 is opened.

With this configuration, the pressure increase in the steam generating unit can be suppressed.

In the absorption heat pump according to the fifth aspect of the present invention, as shown in fig. 1, for example, in the absorption heat pump 1 according to any one of the first to third aspects of the present invention, the vapor generator 80 is composed of a gas-liquid separator 80, and the gas-liquid separator 80 separates the vapor Wv of the medium to be heated from the liquid Wq of the medium to be heated.

With this configuration, it is possible to suppress the liquid from being mixed into the vapor of the medium to be heated flowing out from the vapor generation unit, and to stabilize the liquid level in the gas-liquid separator when the opening degree of the vapor purge valve is changed.

According to the present invention, an excessive increase in pressure of the steam generating portion can be suppressed without operating the safety valve.

Drawings

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

Fig. 2 is a control flowchart for controlling an excessive pressure rise in the gas-liquid separator.

Fig. 3(a) is a graph showing an example of a state when the heating medium vapor is discharged, and (B) is a graph showing another example.

Fig. 4 is a schematic system diagram of a two-stage heating absorption heat pump according to a modification of the embodiment of the present invention.

Description of reference numerals: 1 … absorption heat pump; 10 … absorber; 20 … evaporator; 30 … regenerator; a 40 … condenser; 80 … gas-liquid separator; 88 … safety valve; 89 … a heating medium vapor pipe; 90 … control device; 93 … pressure gauge; 95 … vapor vent valve; wq … is heated with the medium liquid; wv … is heated with the medium vapor.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or similar reference numerals, and redundant description thereof is omitted.

First, an absorption heat pump 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 heat pump 1. The absorption heat pump 1 includes: the absorber 10, the evaporator 20, the regenerator 30, and the condenser 40, and further includes a gas-liquid separator 80 and a control device 90, wherein the absorber 10 constitutes a main device for performing an absorption heat pump cycle of the absorption liquid S (Sa, Sw) and the refrigerant V (Ve, Vg, Vf).

In this specificationThe absorbing liquid is referred to as "dilute solution Sw" or "concentrated solution Sa" depending on properties and positions on the heat pump cycle in order to facilitate the distinction of the heat pump cycle, but is collectively referred to as "absorbing liquid S" when properties and the like are not taken into consideration, and the refrigerant is referred to as "evaporator refrigerant vapor Ve", "regenerator refrigerant vapor Vg" or "refrigerant liquid Vf" depending on properties and positions on the heat pump cycle in order to facilitate the distinction of the heat pump cycle in the same manner, but is collectively referred to as "refrigerant V" when properties and the like are not taken into consideration₂O) as refrigerant V. The medium to be heated W is a generic term for a liquid to be heated Wq, which is a liquid to be heated W, supplied to the absorber 10, a vapor to be heated Wv, which is a gaseous medium to be heated W, a mixed medium Wm, which is a liquid and gas mixed medium W, and a supply water Ws, which is a supply liquid, and is a medium to be heated W replenished from the outside of the absorption heat pump 1. In the present embodiment, water (H) is used₂O) as the heating medium W.

The absorber 10 has, inside thereof: a heat transfer pipe 12 constituting a flow path of the medium W to be heated, and a concentrated solution spreading nozzle 13 for spreading the concentrated solution Sa. The absorber 10 spreads the rich solution Sa from the rich solution spreading nozzle 13, and generates absorption heat when the rich solution Sa absorbs the evaporator refrigerant vapor Ve. The absorption heat is received by the medium W to be heated flowing along the heat transfer pipe 12, and the medium W to be heated is heated.

The evaporator 20 has a heat source pipe 22 inside an evaporator tank 21, and the heat source pipe 22 constitutes a flow path of heat source hot water h as a heat source fluid. The evaporator 20 does not have a nozzle for spreading the refrigerant liquid Vf inside the evaporator tank 21. Therefore, the heat source pipe 22 is disposed so as to be immersed in the refrigerant liquid Vf stored in the evaporator tank 21 (flooded evaporator). In the absorption heat pump, since the pressure in the evaporator is higher than that in the absorption refrigerator, a desired refrigerant vapor can be obtained even in a configuration in which the heat source pipe is immersed in the refrigerant liquid. The evaporator 20 is constituted by: the refrigerant liquid Vf around the heat source tube 22 is evaporated by the heat of the heat source hot water h flowing through the heat source tube 22, and the evaporator refrigerant vapor Ve is generated. A refrigerant liquid pipe 45 for supplying the refrigerant liquid Vf into the evaporator tank 21 is connected to a lower portion of the evaporator tank 21.

The absorber 10 and the evaporator 20 communicate with each other. The structure is as follows: the absorber 10 communicates with the evaporator 20, whereby the evaporator refrigerant vapor Ve generated in the evaporator 20 can be supplied to the absorber 10.

The regenerator 30 has a heat source pipe 32 and a dilute solution distribution nozzle 33, the heat source pipe 32 internally flows heat source hot water h as a heat source fluid that heats the dilute solution Sw, and the dilute solution distribution nozzle 33 distributes the dilute solution Sw. The heat source hot water h flowing through the heat source pipe 32 is the same fluid as the heat source hot water h flowing through the heat source pipe 22 in the present embodiment, but may be a different fluid. The regenerator 30 is configured such that the dilute solution Sw sprayed from the dilute solution spraying nozzle 33 is heated by the heat source hot water h, and thereby the refrigerant V evaporates from the dilute solution Sw to generate the concentrated solution Sa having an increased concentration. The refrigerant V evaporated from the lean solution Sw is configured to move to the condenser 40 as the regenerator refrigerant vapor Vg.

A cooling water pipe 42 through which cooling water c as a cooling medium flows is provided inside the condenser tank 41 of the condenser 40. The condenser 40 is configured to introduce the regenerator refrigerant vapor Vg generated in the regenerator 30, and to cool and condense it with the cooling water c. The regenerator tank and the condenser tank 41 are formed integrally so that the regenerator 30 and the condenser 40 communicate with each other. The regenerator 30 is configured to communicate with the condenser 40, whereby the regenerator refrigerant vapor Vg generated in the regenerator 30 can be supplied to the condenser 40.

The portion of the regenerator 30 that stores the rich solution Sa and the rich solution distribution nozzle 13 of the absorber 10 are connected by a rich solution pipe 35 through which the rich solution Sa flows. A solution pump 35p for pressure-feeding the concentrated solution Sa is provided in the concentrated solution pipe 35. The portion of the absorber 10 that stores the dilute solution Sw and the dilute solution distribution nozzle 33 are connected by a dilute solution pipe 36 through which the dilute solution Sw flows. A solution heat exchanger 38 that exchanges heat between the rich solution Sa and the lean solution Sw is provided in the rich solution pipe 35 and the lean solution pipe 36. The portion of the condenser 40 that stores the refrigerant liquid Vf is connected to a lower portion (typically, a bottom portion) of the evaporator tank 21 by a refrigerant liquid pipe 45 through which the refrigerant liquid Vf flows. A refrigerant pump 46 for pressurizing and feeding the refrigerant liquid Vf is disposed in the refrigerant liquid pipe 45.

A heat source hot water introduction pipe 51 for introducing heat source hot water h into the heat source pipe 22 is connected to one end of the heat source pipe 22 of the evaporator 20. The other end of the heat source pipe 22 and one end of the heat source pipe 32 of the regenerator are connected by a heat source hot water connecting pipe 52. A heat source hot water outflow pipe 53 is connected to the other end of the heat source pipe 32, and guides the heat source hot water h to the outside of the absorption heat pump 1. A heat-source hot-water flow-out pipe 53 is provided with a heat-source hot-water switching valve 53v that can adjust the flow rate of heat-source hot water h flowing inside. A heat-source hot-water bypass pipe 55 is provided between the heat-source hot-water outflow pipe 53 and the heat-source hot-water introduction pipe 51 on the downstream side of the heat-source hot-water switching valve 53 v. A bypass valve 55v that can open and close a flow path is disposed in the heat-source hot-water bypass pipe 55.

The gas-liquid separator 80 is a device that introduces the heating medium W heated by flowing through the heat transfer pipe 12 of the absorber 10 and separates the heating medium vapor Wv from the heating medium liquid Wq. The gas-liquid separator 80 can generate the heating medium vapor Wv by separating the heating medium liquid Wq from the heated heating medium W, and the gas-liquid separator 80 corresponds to a vapor generation unit. A separation liquid pipe 81 is connected to a lower portion (typically, a bottom portion) of the gas-liquid separator 80, and the separation liquid pipe 81 allows the separated heating medium liquid Wq to flow out of the gas-liquid separator 80. A heating medium liquid pipe 82 for guiding the heating medium liquid Wq to the heat conduction pipe 12 is connected to the other end of the separation liquid pipe 81. The other end of heat transfer pipe 12 is connected to the gas phase portion of gas-liquid separator 80 by heated medium-to-be-heated pipe 84 for guiding heated medium W to gas-liquid separator 80. A heating medium steam pipe 89 as a supply steam pipe is connected to an upper portion (typically, a top portion) of the gas-liquid separator 80, and the heating medium steam pipe 89 guides the separated heating medium steam Wv to the outside of the absorption heat pump 1 toward the target. A makeup water pipe 85 is also provided to introduce makeup water Ws from the outside of the absorption heat pump 1, the makeup water Ws being mainly used to replenish the medium W to be heated in an amount corresponding to the amount of steam supplied to the outside of the absorption heat pump 1. The makeup water pipe 85 is connected to a connection portion between the separation liquid pipe 81 and the heating medium liquid pipe 82, and is configured to join the makeup water Ws and the heating medium liquid Wq flowing along the separation liquid pipe 81. A makeup water pump 86 for pressurizing and feeding the makeup water Ws toward the absorber 10 is disposed in the makeup water pipe 85.

A pressure gauge 93 serving as a pressure detecting unit is provided in the heating medium steam pipe 89 near the gas-liquid separator 80, and detects the pressure inside the gas-liquid separator 80. A pressure control valve 99 for adjusting the pressure of the heating medium vapor Wv supplied to the outside of the absorption heat pump 1 is provided in the heating medium vapor pipe 89 on the downstream side of the pressure gauge 93. A safety valve 88 and a vapor vent valve 95 are provided in the heating medium vapor pipe 89 between the pressure gauge 93 and the pressure control valve 99. The relief valve 88 mechanically opens the valve to suppress a pressure increase when the interior of the gas-liquid separator 80 exceeds the target operating pressure and becomes an excessively high pressure (for example, the maximum operating pressure of the gas-liquid separator 80). The vapor-discharge valve 95 is independent of the relief valve 88, and discharges the fluid in the heating medium vapor pipe 89 in order to suppress a rise in pressure inside the gas-liquid separator 80. The vapor vent valve 95 is configured to be adjustable in opening degree.

The control device 90 controls the operation of the absorption heat pump 1. The controller 90 is connected to the solution pump 35p, the refrigerant pump 46, and the makeup water pump 86 via signal cables, and is configured to be able to control the start and stop of the

pumps

35p, 46, and 86. The control device 90 is connected to the heat-source hot-water switching valve 53v and the bypass valve 55v via signal cables, and is configured to be capable of adjusting the opening degrees of the

valves

53v and 55 v. The controller 90 is connected to the pressure gauge 93 via a signal cable, and is configured to receive, as a signal, the pressure detected by the pressure gauge 93. The controller 90 is connected to the vapor vent valve 95 and the pressure control valve 99 via signal cables, and is configured to be able to adjust the opening degrees of the vapor vent valve 95 and the pressure control valve 99, respectively.

With continued reference to fig. 1, the operation of the absorption heat pump 1 is explained. When the absorption heat pump 1 is operating normally, the heat source hot water switching valve 53v and the pressure control valve 99 are opened, and the bypass valve 55v and the vapor discharge valve 95 are closed. First, the refrigerant-side cycle is explained. The condenser 40 receives the regenerator refrigerant vapor Vg evaporated in the regenerator 30, and condenses it into the refrigerant liquid Vf by cooling with the cooling water c flowing through the cooling water pipe 42. The condensed refrigerant liquid Vf is sent to the evaporator tank 21 by the refrigerant pump 46. The refrigerant liquid Vf sent to the evaporator tank 21 is heated and evaporated by the heat source hot water h flowing through the heat source pipe 22 to become the evaporator refrigerant vapor Ve. The evaporator refrigerant vapor Ve generated in the evaporator 20 moves toward the absorber 10 communicating with the evaporator 20.

Next, circulation on the solution side will be described. In the absorber 10, the rich solution Sa is dispersed from the rich solution dispersing nozzle 13, and the dispersed rich solution Sa absorbs the evaporator refrigerant vapor Ve moving from the evaporator 20. The concentrated solution Sa of the evaporator refrigerant vapor Ve is absorbed and the concentration thereof decreases to become a dilute solution Sw. In the absorber 10, absorption heat is generated when the rich solution Sa absorbs the evaporator refrigerant vapor Ve. The medium W to be heated flowing through the heat transfer pipe 12 is heated by the absorption heat. The absorber 10 absorbs the rich solution Sa of the evaporator refrigerant vapor Ve, and the concentration thereof decreases to become a lean solution Sw, which is stored in the lower portion of the absorber 10. The stored lean solution Sw flows toward the regenerator 30 in the lean solution pipe 36 due to the difference between the internal pressures of the absorber 10 and the regenerator 30, exchanges heat with the rich solution Sa in the solution heat exchanger 38, is lowered in temperature, and reaches the regenerator 30.

The dilute solution Sw sent to the regenerator 30 is distributed from the dilute solution distribution nozzle 33, heated by the heat source hot water h (about 80 ℃ in the present embodiment) flowing through the heat source pipe 32, and the refrigerant in the distributed dilute solution Sw is evaporated to become the concentrated solution Sa and stored in the lower portion of the regenerator 30. On the other hand, the refrigerant V evaporated from the lean solution Sw moves to the condenser 40 as the regenerator refrigerant vapor Vg. The rich solution Sa stored in the lower portion of the regenerator 30 is pressure-fed by the solution pump 35p to the rich solution distribution nozzle 13 of the absorber 10 via the rich solution pipe 35. The rich solution Sa flowing through the rich solution pipe 35 is subjected to heat exchange with the lean solution Sw in the solution heat exchanger 38 to increase its temperature, and then flows into the absorber 10 and is dispersed from the rich solution dispersion nozzle 13. The rich solution Sa is pressurized by the solution pump 35p to enter the absorber 10, and rises in temperature in the absorber 10 with absorption of the evaporator refrigerant vapor Ve. The rich solution Sa returned to the absorber 10 absorbs the evaporator refrigerant vapor Ve, after which the same cycle is repeated.

In the course of the absorption heat pump cycle as described above, the absorption heat generated when the evaporator refrigerant vapor Ve is absorbed by the rich solution Sa in the absorber 10 heats the heating medium liquid Wq to become wet vapor (mixed heating medium Wm), and the wet vapor is guided to the gas-liquid separator 80. The mixed heating medium Wm that flows into the gas-liquid separator 80 is separated into the heating medium vapor Wv and the heating medium liquid Wq. The heating medium vapor Wv separated by the gas-liquid separator 80 flows out to the heating medium vapor pipe 89 and is supplied to a vapor utilization place (demand target) outside the absorption heat pump 1. That is, the heating medium vapor Wv is taken out from the absorption heat pump. In this way, the absorption heat pump 1 is configured as a second absorption heat pump capable of extracting the medium W to be heated, which is at a temperature equal to or higher than the temperature of the driving heat source. The amount of the medium W to be heated supplied to the outside is supplied from the outside of the absorption heat pump 1 as the makeup water Ws. On the other hand, the heating medium liquid Wq separated in the gas-liquid separator 80 flows out to the separation liquid pipe 81, joins the makeup water Ws flowing along the makeup water pipe 85, flows through the heating medium liquid pipe 82 as the heating medium liquid Wq, and is supplied into the heat guide pipe 12. The respective devices constituting the absorption heat pump 1 are controlled by a control device 90.

As described above, the controller 90 receives the pressure signal from the pressure gauge 93 at any time when the absorption heat pump 1 is operated. In order to achieve stable supply of the heating medium vapor Wv to the demand target, the control device 90 adjusts the opening degree of the pressure control valve 99 so that the pressure detected by the pressure gauge 93 reaches a predetermined supply pressure of the heating medium vapor Wv (hereinafter referred to as "target pressure P1"). However, even if such control is performed, the pressure in the gas-liquid separator 80 may increase, and may also increase to a pressure at which the relief valve 88 opens (hereinafter referred to as "opening pressure PS", for example, the maximum use pressure of the gas-liquid separator 80). Since the safety valve 88 is basically opened to the atmosphere for the purpose of discharging, when the safety valve 88 is opened, a large noise may be generated, or white smoke or dense fog may accompany the periphery of the discharge medium vapor Wv, which may have a large influence on the environment. In addition, in some enterprises, it is considered that the discharge of the vapor from the safety valve 88 is an accident, and in view of such a situation, it is not preferable to operate the safety valve 88. It is therefore preferable not to raise the pressure to such an extent that the relief valve 88 opens. Therefore, in the present embodiment, the following control is performed to suppress the pressure in the gas-liquid separator 80 from rising to such a level that the relief valve 88 opens.

Fig. 2 is a flowchart of control for suppressing an excessive increase in the internal pressure of the gas-liquid separator 80. In the following description of the control, reference will be made to fig. 1 as appropriate when referring to the structure of the absorption heat pump 1. In this control, first, the controller 90 determines whether or not the value detected by the pressure gauge 93 is equal to or higher than the output suppression pressure P2 (S1). The output suppression pressure P2 is an arbitrary pressure that exceeds the target pressure P1 and is lower than the opening pressure PS, and may be determined in consideration of a pressure that is desired to avoid a further increase in pressure in the gas-liquid separator 80. The output suppression pressure P2 corresponds to the third prescribed pressure. In the step (S1) of determining whether or not the value detected by the pressure gauge 93 is equal to or greater than the output suppression pressure P2, if the value is not equal to or greater than the output suppression pressure P2, the process returns to the step (S1) of determining whether or not the value detected by the pressure gauge 93 is equal to or greater than the output suppression pressure P2. On the other hand, if the output suppression pressure P2 is equal to or higher than the predetermined value, the control device 90 performs an output suppression measure (S2). In the present embodiment, as the output suppression means, the opening degree of the heat-source hot-water switching valve 53v and/or the bypass valve 55v is adjusted so that part or all of the heat-source hot water h introduced into the evaporator 20 and the regenerator 30 is not introduced into the evaporator 20 and the regenerator 30, thereby suppressing the generation of absorption heat in the absorber 10.

After the output suppression measure is performed, the control device 90 determines whether or not the value detected by the pressure gauge 93 is equal to or less than the output suppression measure cancellation pressure P2' (S3). The output restraining-measure release pressure P2' is a pressure that is lower than the output restraining pressure P2 by only a predetermined differential. When the output suppression measure cancellation pressure P2 'is equal to or lower than the output suppression measure cancellation pressure P4', the process returns to the step of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the output suppression pressure P2 (S1). On the other hand, if the output suppression measure canceling pressure P2 'is not equal to or lower than the output suppression measure canceling pressure P2', the control device 90 determines whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor discharge increasing pressure P3 (S5). The vapor purge increase pressure P3 is an arbitrary pressure exceeding the output suppressing pressure P2 and being lower than the opening pressure PS, and is intended to correspond to the first predetermined pressure as a trigger for increasing the amount of discharge of the heating medium vapor Wv from the vapor purge valve 95 by increasing the opening degree of the vapor purge valve 95 under self-control (including opening from the closed state) before the safety valve 88 opens. From the viewpoint of suppressing the discharge of the heating medium vapor Wv, the vapor discharge increase pressure P3 is preferably set to an extremely high pressure. Further, the vapor vent valve 95 preferably has a vapor vent capacity capable of discharging the medium-to-be-heated vapor Wv at a flow rate equal to or greater than the flow rate of the generated medium-to-be-heated vapor Wv when the output suppression measure is implemented, in the fully opened state. That is, the vapor vent valve 95 may not have a vapor vent capacity of the same degree as the safety valve 88 (typically, a vapor vent capacity capable of discharging the heating medium vapor Wv at a flow rate equal to or greater than the generation flow rate of the heating medium vapor Wv in the normal operation), in other words, may have a vapor vent capacity smaller than the capacity of the safety valve 88, and the vapor vent valve 95 may be smaller in size or diameter than the safety valve 88.

In the step (S5) of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor discharge increase pressure P3, the controller 90 opens the vapor discharge valve 95 to discharge the heating medium vapor Wv when the value is equal to or higher than the vapor discharge increase pressure P3 (S6). In the present embodiment, the opening operation of the primary steam vent valve 95 is not fully opened, but is opened only by a predetermined opening degree. After the opening operation of the vapor vent valve 95 is performed (S6), the process returns to the step of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor vent increase pressure P3 (S5), and the opening degree of the vapor vent valve 95 is maintained. While the vapor-discharge valve 95 is maintained at the opening degree in a fully or partially opened state, the heating medium vapor Wv continues to be discharged, and therefore the pressure detected by the pressure gauge 93 typically continues to decrease. Then, in the step (S5) of determining again whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor discharge increase pressure P3, if the value is still equal to or higher than the vapor discharge increase pressure P3, the vapor vent valve 95 is opened by a predetermined opening degree (S6). In this way, even if the opening degree of the vapor vent valve 95 is gradually increased and the value detected by the pressure gauge 93 is equal to or higher than the vapor vent increase pressure P3 after reaching the fully open state, the step of opening the vapor vent valve 95 is performed (S6), but since the opening degree of the vapor vent valve 95 is not physically increased, the fully open state is maintained in practice, and the step of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor vent increase pressure P3 is returned (S5).

In the step of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor discharge increase pressure P3 (S5), the controller 90 determines whether or not the value detected by the pressure gauge 93 is equal to or lower than the vapor discharge decrease pressure P3' when the value is not equal to or higher than the vapor discharge increase pressure P3 (S7). The vapor-discharge reducing pressure P3' is a pressure lower than the vapor-discharge increasing pressure P3 by the predetermined differential Δ P, and corresponds to the second prescribed pressure. The vapor emission reduction pressure P3' is typically a pressure that exceeds the target pressure P1. In the step (S7) of determining whether or not the value detected by the pressure gauge 93 is equal to or less than the vapor discharge reduction pressure P3 ', when the value is equal to or less than the vapor discharge reduction pressure P3', the process returns again to the step (S5) of determining whether or not the value detected by the pressure gauge 93 is equal to or more than the vapor discharge increase pressure P3, and the opening degree of the vapor discharge valve 95 is maintained. On the other hand, in the step of determining whether or not the value detected by the pressure gauge 93 is equal to or less than the vapor discharge reduction pressure P3 '(S7), the controller 90 determines whether or not the vapor discharge valve 95 is in the closed state when the value is equal to or less than the vapor discharge reduction pressure P3' (S8).

In the step of determining whether or not the vapor vent valve 95 is in the closed state (S8), when the vapor vent valve 95 is not in the closed state, the controller 90 causes the vapor vent valve 95 to perform the closing operation to reduce the discharge amount of the heating medium vapor Wv (S9). In the present embodiment, the fully closed state is not achieved by the closing operation of the primary steam discharge valve 95, but only a predetermined opening degree is closed. After the closing operation of the vapor vent valve 95 is performed (S9), the process returns to the step of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor vent increase pressure P3 (S5), and the opening degree of the vapor vent valve 95 is maintained. On the other hand, in the step of determining whether or not the vapor vent valve 95 is in the closed state (S8), when the vapor vent valve 95 is in the closed state, the process returns to the step of determining whether or not the value detected by the pressure gauge 93 is equal to or less than the output suppression measure cancellation pressure P2' (S3), and the above-described flow is repeated thereafter.

As described above, in the present embodiment, the vapor vent valve 95 is opened only by a predetermined opening degree in stages at predetermined intervals (every time the determination of the step (S5) is made) when the value detected by the pressure gauge 93 maintains the vapor discharge increase pressure P3 or more, and the vapor vent valve 95 maintains its opening degree when the value detected by the pressure gauge 93 is smaller than the vapor discharge increase pressure P3 and exceeds the vapor discharge decrease pressure P3'; when the value detected by the pressure gauge 93 is maintained at the vapor discharge reduction pressure P3' or less, the vapor discharge valve 95 is closed at predetermined intervals (every time the determination in the step (S7) is made) in a stepwise manner by a predetermined opening degree. The absorption heat pump 1 opens a part or all of the vapor vent valve 95 to discharge the heating medium vapor Wv, and thereby can suppress a further increase in pressure even when the internal pressure of the gas-liquid separator 80 further increases to the vapor vent increasing pressure P3 until the pressure reducing effect of the output suppressing means (S2) occurs. In the process of discharging the heating medium vapor Wv through the vapor discharge valve 95, the vapor discharge valve 95 is opened in stages, so that unnecessary discharge of the heating medium vapor Wv is avoided, and the pressure detected by the pressure gauge 93 can be reduced by the minimum discharge amount of the heating medium vapor Wv, so that the safety valve 88 can be prevented from operating. Further, since the discharge amount of the heating medium vapor Wv via the vapor discharge valve 95 does not suddenly discharge a large amount of vapor such as the vapor discharge of the safety valve 88, but gradually increases from a small amount, it is possible to reduce the influence of the discharge of the heating medium vapor Wv on the level and pressure fluctuation of the heating medium liquid Wq in the gas-liquid separator 80, to continue the operation, and to reduce the noise accompanying the discharge of the heating medium vapor Wv. Further, a muffler may be attached to the discharge destination of the vapor discharge valve 95 to reduce noise or eliminate noise when the medium to be heated vapor Wv is discharged. Alternatively, the discharged medium-to-be-heated steam Wv may be guided into a water storage tank in which the makeup water Ws is stored, and the heat recovery may be performed by reducing noise or eliminating noise at the time of discharging the medium-to-be-heated steam Wv, and by preheating the makeup water Ws with the discharged medium-to-be-heated steam Wv. In this way, the discharged medium-to-be-heated vapor Wv can be effectively used. Alternatively, the discharged medium to be heated vapor Wv may be guided into another water storage tank, and noise may be reduced or eliminated when the medium to be heated vapor Wv is discharged.

Fig. 3(a) shows an example of a situation when the medium-to-be-heated vapor Wv is discharged, the ordinate of the graph of fig. 3(a) shows, from above, the discharge amount of the medium-to-be-heated vapor Wv from the vapor discharge valve 95, the pressure detected by the pressure gauge 93, and the open/close state of the vapor discharge valve 95, and the abscissa shows time, in the example shown in fig. 3(a), the pressure detected by the pressure gauge 93 reaches the vapor discharge increase pressure P3 at time T1, and therefore, only during the period in which the pressure detected by the pressure gauge 93 is equal to or higher than the vapor discharge increase pressure P3, the vapor discharge valve 95 is opened in stages (S6), and at this time, the vapor discharge valve 95 is gradually decreased at predetermined time intervals T865L, and when the opening degree of the vapor discharge valve 95 is increased by the predetermined opening degree a, then, typically during the period in which the vapor discharge valve 95 is opened, the pressure detected by the pressure gauge 93 is smaller than the vapor discharge increase pressure P3 and exceeds the vapor discharge decrease pressure P3' (at time T6-T3), and when the opening degree of the vapor discharge valve 93 is decreased by the predetermined time T369, the predetermined time T3625, the opening degree of the vapor discharge valve 95 is decreased at each time T3695, and when the opening degree of the vapor discharge valve 3695 is decreased by the predetermined time T369.

As described above, according to the absorption heat pump 1 of the present embodiment, when the value detected by the pressure gauge 93 is equal to or greater than the vapor discharge increase pressure P3 that is smaller than the opening pressure PS of the relief valve 88, the opening degree of the vapor discharge valve 95 is gradually increased little by little, and the discharge amount of the medium vapor to be heated Wv is increased stepwise, so that the internal pressure of the gas-liquid separator 80 can be reduced by the minimum discharge amount of the medium vapor to be heated Wv, and the generation of noise, white smoke, or thick mist can be suppressed, and the internal pressure of the gas-liquid separator 80 can be suppressed from excessively increasing, without operating the relief valve 88, because the medium vapor to be heated Wv is the minimum discharge amount.

In the above description, the valve opening time interval and the opening width of the opening when the vapor vent valve 95 is opened and the valve closing time interval and the closing width of the closing when the vapor vent valve 95 is closed are set to be the same, but they may be changed, for example, the valve opening time interval may be shortened to increase the opening degree of the opening when the vapor vent valve 95 is opened, and the valve closing time interval may be lengthened to decrease the opening degree of the closing when the vapor vent valve is closed, and it is preferable to shorten the predetermined time interval T L and/or increase the predetermined opening degree a during the period from the time T1 to the time T2 when the vapor vent valve is opened, and to lengthen the predetermined time interval T L and/or decrease the predetermined opening degree a during the period from the time T3 to the time T4 when the vapor vent valve is closed, so that the internal pressure of the gas-liquid separator 80 (vapor generating portion) is prevented from rapidly increasing and the pressure of the liquid level Wq in the gas-liquid separator 80 and the pressure may be stably changed to return to the normal operation along with the reduction of the discharge of the heated medium vapor Wv.

In the above description, the vapor purge valve 95 increases the valve opening by the predetermined opening a at each time at the predetermined time interval T L and decreases the valve opening by the predetermined opening a at each time at the predetermined time interval T L, but as shown in fig. 3(B), the valve opening may be continuously changed at the predetermined opening/closing speed, so that the fluctuation of the liquid level and the pressure of the heating medium liquid Wq in the gas-liquid separator 80 accompanying the discharge of the heating medium vapor Wv can be further reduced, and a stable operation can be performed.

In the above description, as the output suppression measure, a part or all of the heat source hot water h introduced into the evaporator 20 and the regenerator 30 is not introduced into the evaporator 20 and the regenerator 30, but instead or together with this, a part or all of the cooling water c introduced into the condenser 40 may not be introduced into the condenser 40. That is, any of measures for not introducing a part or all of the heat source hot water h to the evaporator 20 and the regenerator 30 and measures for not introducing a part or all of the cooling water c to the condenser 40 may be performed alone, or they may be performed in combination.

In the above description, the output suppression measure is implemented when the value detected by the pressure gauge 93 is equal to or greater than the output suppression pressure P2, but the output suppression measure may be omitted. In this case, the following steps are omitted from the flow shown in fig. 2: the step (S1) of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the output suppression pressure P2, the step (S2) of performing the output suppression measure, the step (S3) of determining whether or not the value detected by the pressure gauge 93 is equal to or lower than the output suppression measure release pressure P2', and the step (S4) of releasing the output suppression measure may be set to return to the step (S5) of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor discharge increase pressure P3, when the step (S8) of determining whether or not the vapor discharge valve 95 is closed, from the step (S3528) of determining whether or not the value detected by the pressure gauge 93 is equal to or higher than the vapor discharge increase pressure P3. In this way, when the output suppression measure is omitted, the vapor vent valve 95 preferably has a vapor vent capacity capable of discharging the heating medium vapor Wv at a flow rate equal to or greater than the generation flow rate of the heating medium vapor Wv in the fully open state during the normal operation.

In the above description, the relief valve 88 is provided in the heating medium steam pipe 89, but may be provided in the gas-liquid separator 80. Similarly, a steam release valve 95 may be provided in the gas-liquid separator 80 instead of the heating medium steam pipe 89. The pressure gauge 93 is also provided in the heating medium steam pipe 89, but may be provided in the gas-liquid separator 80. When the relief valve 88, the steam vent valve 95, or the pressure gauge 93 is provided in the gas-liquid separator 80, it is preferable to provide the gas-liquid separator 80 in a part of the gas phase portion.

In the above description, the vapor generation unit is constituted by the gas-liquid separator 80, but the heating target medium vapor Wv may be generated in the heat transfer pipe 12 of the absorber 10, and the heat transfer pipe 12 may be used as the vapor generation unit, in which case the heating target medium vapor pipe 89 is preferably connected to the heated heating target medium pipe 84. However, since the internal pressure of the steam generating part fluctuates when the steam release valve 95 is opened, the gas-liquid separator 80 that can absorb the fluctuation of the liquid level accompanying the fluctuation of the internal pressure and stabilize the liquid level is preferably used as the steam generating part.

In the above description, the evaporator 20 is flooded, but may be distributed. When the evaporator is a distributed type, a refrigerant liquid distribution nozzle for distributing the refrigerant liquid Vf may be provided in an upper portion of the evaporator tank, and an end of the refrigerant liquid pipe 45 connected to a lower portion of the evaporator tank 21 in a flooded type may be connected to the refrigerant liquid distribution nozzle. Further, a pipe and a pump for supplying the refrigerant liquid Vf to the refrigerant liquid distribution nozzle may be provided in the lower portion of the evaporator tank.

In the above description, the case where the absorption heat pump 1 is a single stage has been described, but may be a multi-stage one.

Fig. 4 illustrates a configuration of a two-stage heating type absorption heat pump 1A, in the absorption heat pump 1A, an absorber 10 and an evaporator 20 of the absorption heat pump 1 shown in fig. 1 are divided into a high temperature side high temperature absorber 10H and a high temperature evaporator 20H, and a low temperature side low temperature absorber 10L and a low temperature evaporator 20L, the high temperature absorber 10H has a higher internal pressure than the low temperature absorber 10L, the high temperature evaporator 20H has a higher internal pressure than the low temperature evaporator 20L, the high temperature absorber 10H and the high temperature evaporator 20H are communicated with each other at an upper portion thereof so that vapor of the refrigerant V in the high temperature evaporator 20H can move to the high temperature absorber 10H, the low temperature absorber 10L and the low temperature evaporator 20L are communicated with each other so that vapor of the refrigerant V in the low temperature evaporator 20L can move to the absorption 10L, a heated medium Wq is introduced into the high temperature absorber 10H, a heated heat source H is heated by the low temperature evaporator 20H, the low temperature absorber 10H absorbs vapor of the refrigerant V23, and the high temperature heat medium liquid Wq is heated by the absorption liquid w/w absorption heat absorber 20 when the high temperature absorber 10H absorbs the vapor of the high temperature evaporator 20H and the high temperature evaporator 20H/V/.

Claims

1. An absorption heat pump that generates vapor of a medium to be heated by absorbing heat of an introduced heat source fluid by an absorption heat pump cycle of an absorbent and a refrigerant, the absorption heat pump comprising:

a steam generation unit that generates steam of the medium to be heated supplied to a demand target;

a pressure detection unit that detects a pressure of the steam generation unit;

a safety valve provided in the steam generation unit or a supply steam pipe that allows the steam of the medium to be heated generated by the steam generation unit to flow out toward a target to be heated;

a steam discharge valve provided in the supply steam pipe or the steam generating unit; and

a control device that opens the vapor release valve when the pressure detected by the pressure detection unit exceeds a target pressure of the vapor generation unit and is equal to or higher than a first predetermined pressure that is lower than a pressure at which the relief valve opens,

the control means controls the opening degree of the vapor-discharge valve in such a manner that:

the control device increases the opening degree of the vapor purge valve in a stepwise manner at predetermined intervals at a predetermined opening degree smaller than the opening degree from the fully closed state to the fully opened state when the pressure detected by the pressure detection unit maintains the pressure equal to or higher than the first predetermined pressure,

the control device maintains the opening degree of the vapor purge valve when the pressure detected by the pressure detection portion exceeds a second predetermined pressure and is less than the first predetermined pressure, the second predetermined pressure being a pressure less than the first predetermined pressure,

the control device may gradually reduce the opening degree of the vapor purge valve at predetermined intervals to a predetermined opening degree smaller than the opening degree from the fully open state to the fully closed state when the pressure detected by the pressure detection unit maintains the pressure equal to or lower than the second predetermined pressure.

2. An absorption heat pump according to claim 1,

the control means controls the opening degree of the vapor-discharge valve in such a manner that: the change speed of the opening degree of the vapor vent valve when the opening degree of the vapor vent valve is gradually reduced is slower than when the opening degree of the vapor vent valve is gradually increased.

3. An absorption heat pump according to claim 1 or 2,

the control device performs an output suppression measure for suppressing the output of the absorption heat pump when the pressure detected by the pressure detection unit exceeds the target pressure of the steam generation unit and is equal to or higher than a third predetermined pressure, which is lower than the pressure at which the safety valve opens.

4. An absorption heat pump according to claim 1 or 2,

the vapor generation unit is configured by a gas-liquid separator that separates vapor of the medium to be heated from liquid of the medium to be heated.