DE112017006707B4 - Absorption chiller - Google Patents

Abstract

Absorption refrigeration machine, comprising an evaporator (1), an absorber (9), a low-pressure expeller (22), a high-pressure expeller (33), an auxiliary absorber (16), an auxiliary expeller (44), a condenser (40) and a solution pump (14) , wherein the gas phase sections of the evaporator (1) and the absorber (9) are connected, the gas phase sections of the low-pressure expeller (22) and the auxiliary absorber (16) are connected, the gas phase sections of the high-pressure expeller (33), the auxiliary expeller (44) and the Condenser (40) are connected, a solution pipeline running from the absorber (9) to the high-pressure expeller (33) has a branching section, a solution pipeline is coupled to the branching section, which runs to the low-pressure expeller (22), the solution pump (14) on the from the absorber (9) solution pipeline running to the branching section is provided and a solution pipeline running from the high-pressure expeller (33) to the absorber (9) has a combining section which is coupled to a solution pipeline running from the low-pressure expeller (22).

Description

Technical area

The present invention relates to an absorption refrigerator.

General state of the art

Absorption chillers can be operated with heat, which is why cold can be provided as a drive heat source using hot water released as waste heat. In a single-effect cycle process, an expeller with hot water of around 90 °C as the driving heat source can provide cooling of around 7 °C.

Patent document 1 describes that in a two-stage absorption cycle process, two expellers can provide cold as a drive heat source with hot water of a lower temperature than in a single-effect cycle process.

Patent Document 2 describes an absorption refrigerator that combines a single-effect cycle and a two-stage absorption cycle. It consists of a single-effect cycle process and an auxiliary effect cycle process, with a high-pressure expeller and a low-pressure expeller being provided on the side of the single-effect cycle process and a serial flow taking place in which the entire solution circulates successively through absorbers, high-pressure expellers, low-pressure expellers and absorbers. The configuration described is such that an auxiliary absorber and an auxiliary expeller are present on the part of the auxiliary effect cycle process, the gas phase section of the auxiliary absorber being connected to the low-pressure expeller and the gas phase section of the auxiliary expeller being connected to a gas phase section of the high-pressure expeller and a capacitor. In Patent Document 2, the hot water from the driving heat source can be used from the temperature required for the single-effect cycle process to the temperature required for the two-stage absorption cycle process. Patent Document 3 shows a two-stage low-temperature water absorption refrigerator, and more particularly, a two-stage low-temperature water absorption refrigerator capable of heating a room and supplying hot water.

State of the art documents

Patent documents

• Patent Document 1: Japanese Patent Laid-Open Publication JP 2004 - 211 979 A ( 6 )
• Patent Document 2: Korean Patent Publication KR 10 2011 0 014 376 A ( 2 )
• Patent document 3: KR 10 1 652 484 B1

Brief description of the invention

Task of the invention

An effective means of saving energy is to generate and reuse as much cold as possible from a waste heat source. A conceivable means for this is, for example, to use approximately 90 ° C warm water as a drive heat source in a single-effect cycle process and then to use the cooled hot water again as a drive heat source in a two-stage absorption cycle process. However, in this case, two separate absorption chillers are required for the respective cycle processes, and there are two piping systems for cold water and cooling water, which is why the design of the piping is complicated, the installation area is large and the costs increase. If there are two absorption chillers, the number of solution pumps and refrigerant pumps essentially doubles, which increases the energy requirement.

The technique of Patent Document 2 is a cycle process that solves the above problem using a single absorption refrigerator. However, in the technique of Patent Document 2, in serial flow, all the solution flows from the absorber of the single effect cycle to the high pressure expeller comprising a falling film type heat exchanger, and the entire solution from the high pressure expeller flows into the low pressure expeller comprising a falling film type heat exchanger. The solution thus flows into the low-pressure expeller after being concentrated at the high-pressure expeller. Therefore, the solution concentrated at the low pressure expeller has a maximum concentration. For the same solution pressure, the solution temperature is higher at high concentration; Because the concentration of the solution at the low-pressure expeller is higher than the solution concentrated at the high-pressure expeller, the temperature difference to the drive heat source is reduced, which is why the required heat exchange surface increases.

In the case of a serial flow, if the heat exchangers of the high-pressure expeller and the low-pressure expeller are of different sizes, it is impossible to set the appropriate solution flow rate. Particularly when falling film type heat exchangers are used on the high pressure expeller and the low pressure expeller and in an effort to achieve a To achieve a heat exchanger size that is suitable for the dispersion density of the solution, the heat exchanger size is fixed, the degree of freedom in the arrangement of the devices is reduced.

Since in the single-effect cycle process the entire solution circulates successively through the absorber, the high-pressure expeller and the low-pressure expeller, a solution pump is installed at the respective outlets, which is why increased energy consumption due to the solution pumps is to be expected. In order to exploit the advantages of heat operation in an absorption chiller, an effective means is to reduce the energy consumption for pump operation.

The present invention is based on the object of recovering heat from a single waste heat source from approximately 90 ° C until the low temperature is reached and providing cold, as well as making the low-pressure expeller compact, in an absorption refrigeration machine in which a single-effect cycle process is combined with a two-stage absorption cycle process To ensure freedom of arrangement of the individual heat exchangers and to design the number of solution pumps appropriately.

Means for solving the tasks

An absorption refrigerator of the present invention includes an evaporator, an absorber, a low-pressure expeller, a high-pressure expeller, an auxiliary absorber, an auxiliary expeller, a condenser and a solution pump, wherein the gas phase sections of the evaporator and the absorber are in communication, the gas phase sections of the low-pressure expeller and the auxiliary absorber in The gas phase sections of the high-pressure expeller, the auxiliary expeller and the condenser are connected, a solution pipeline running from the absorber to the high-pressure expeller has a branching section, a solution pipeline is coupled to the branching section and runs to the low-pressure expeller, the solution pump is connected to the solution pipe running from the absorber to the branching section Solution pipeline is provided and a solution pipeline running from the high-pressure expeller to the absorber has a union section which is coupled to a solution pipeline running from the low-pressure expeller.

Effect of the invention

According to the present invention, in an absorption refrigerator in which a single-effect cycle is combined with a two-stage absorption cycle, heat can be recovered from a single waste heat source from about 90 ° C to low temperature and cold can be provided, and the low-pressure expeller can be made compact.

In addition, according to the present invention, freedom of arrangement of individual heat exchangers can be provided, the number of solution pumps can be reduced, and energy consumption can be reduced.

Short description of the characters

• 1 eine schematische Ansicht des Aufbaus einer Absorptionskältemaschine eines Ausführungsbeispiels; und
• 2 ein Dühring-Diagramm des Absorptionskreisprozesses der Absorptionskältemaschine des Ausführungsbeispiels.

Show it:

• 1 a schematic view of the structure of an absorption refrigeration machine of an exemplary embodiment; and
• 2 a Dühring diagram of the absorption cycle process of the absorption refrigerator of the exemplary embodiment.

Embodiment of the invention

The present invention relates to an absorption refrigeration machine in which a heat source medium is supplied to three expellers and which comprises two independent solution cycle processes.

A specific exemplary embodiment of the present invention is described below with reference to the figures. In the figures, the same reference numbers refer to the same or corresponding elements. Example embodiment

1 is a schematic view of a cycle flow of an absorption refrigeration machine of the exemplary embodiment.

2 is a curve diagram showing the state of the cycle of the present invention using a Dühring diagram with a solution isoconcentration curve. The horizontal axis shows the solution temperature and the vertical axis shows the pressure.

At E, A, LG, HG, AA, AG, C in 1 and E, A, LG, HG, AA, AG, C in 2 these are the same elements.

First, the cycle process of the absorption refrigerator of the present invention will be described.

The absorption chiller includes a single-effect cycle process side and an auxiliary cycle process side, and a solution circulates independently in both cycle processes. The individual effect cycle process side has, among other things, an evaporator 1, an absorber 9, a low-pressure expeller 22, a high-pressure expeller 33, a condenser 40, a low-temperature solution heat exchanger 55 and a high-temperature solution heat exchanger 56 as heat exchange elements, a refrigerant pump 6 and solution pumps 14, 30. The auxiliary circuit process side has, among other things, an auxiliary absorber 16, an auxiliary expeller 44 and a medium-temperature solution heat exchanger 57 as heat exchange elements and solution pumps 29, 54.

Next, the operation of the single effect circuit process side will be described.

At the evaporator 1, refrigerant accumulated in the lower section of the evaporator 1 is passed through a refrigerant pipe 7 to a spray device 2 by the refrigerant pump 6 and sprayed out of the heat transfer pipe of the heat exchanger 3. The sprayed refrigerant is heated by cold water flowing in the heat transfer pipe of the heat exchanger 3, part of which becomes refrigerant vapor and is passed through a separator 8 to the absorber 9. Latent heat of vaporization when the refrigerant evaporates is used to cool the cold water flowing in the heat transfer pipeline of the heat exchanger 3. Cold water pipes 4, 5 are connected to the heat exchanger 3, through which cold water flows to provide cold on the load side.

In the absorber 9, concentrated solution is sprayed from the heat transfer pipeline of the heat exchanger 11 by a spray device 10 at the low-pressure expeller 22 and at the high-pressure expeller 33. The sprayed solution absorbs refrigerant vapor from the evaporator 1 so that its concentration decreases, and passes through the low-temperature solution heat exchanger 55 by means of the solution pump 14 arranged along a solution pipe 15, whereupon it branches at a branch point A (branch section), a part via a flow control valve 32 (flow control device) of a solution pipeline 31 to the low-pressure expeller 22. The other part of the solution branching at branch point A passes through the high-temperature solution heat exchanger 56 and is directed to the high-pressure expeller 33. In the heat transfer pipe of the heat exchanger 11 of the absorber 9, cooling water flows to remove absorption heat generated when the refrigerant vapor is absorbed by the solution. Cooling water pipes 12, 13 are connected to the heat exchanger 11.

At the low-pressure expeller 22, the solution, the concentration of which has decreased at the absorber 9, is sprayed out of the heat transfer pipeline of the heat exchanger 24 by the spray device 23. The sprayed solution is heated by the heat source medium flowing in the heat transfer pipe of the heat exchanger 24 and separated into concentrated solution and refrigerant vapor. The concentrated solution passes through the solution pipeline 27 and is merged with the solution from the high pressure expeller 33 at a merging point B (merging section). The refrigerant vapor is passed via the separator 21 to the auxiliary absorber 16 on the auxiliary circuit process side. Heat source medium pipes 25, 26 are connected to the heat exchanger 24 of the low-pressure expeller 22.

At the high-pressure expeller 33, the solution whose concentration has decreased at the absorber 9 and whose temperature has increased at the low-temperature solution heat exchanger 55 and at the high-temperature solution heat exchanger 56 is sprayed from the heat transfer pipeline of the heat exchanger 35 by the spray device 34. The sprayed solution is heated by the heat source medium flowing in the heat transfer pipe of the heat exchanger 35 and separated into concentrated solution and refrigerant vapor. The concentrated solution is passed to the combining point B via the high-temperature solution heat exchanger 56, which is arranged along the course of a solution pipeline 49. The concentrated solution from the low-pressure expeller 22 and the high-pressure expeller 33 is brought together at the merging point B, experiences a pressure increase at the solution pump 30 and is passed through the low-temperature solution heat exchanger 55 to the absorber 9. The refrigerant vapor, which was separated from the concentrated solution at the high-pressure expeller 33, is conducted to the condenser 40 via a baffle 39. Heat source medium pipes 36, 37 are connected to the heat exchanger 35 of the high-pressure expeller 33.

At the condenser 40, the refrigerant vapor separated from the concentrated solution at the high-pressure expeller 33 and the auxiliary expeller 44 is cooled and condensed by the cooling water flowing in the heat transfer pipe of the heat exchanger 41. The condensed refrigerant is passed through a refrigerant pipeline 50 to the evaporator 1. Cooling water pipes 42, 43 are connected to the heat exchanger 41.

Next, the operation of the auxiliary circuit process side will be described.

In the case of the auxiliary absorber 16, concentrated solution is extracted from the heat transfer pipe of the auxiliary expeller 44 by the spray device 17 Heat exchanger 18 sprayed. The sprayed solution absorbs refrigerant vapor from the low-pressure expeller 22 of the single-effect cycle process, thereby decreasing its concentration, and is passed through the medium-temperature solution heat exchanger 57 and to the auxiliary expeller 44 by the solution pump 29 arranged along the solution pipeline 28. In the heat transfer pipeline of the heat exchanger 18 of the auxiliary absorber 16, cooling water flows to remove absorption heat generated when the refrigerant vapor is absorbed by the solution. Cooling water pipes 19, 20 are connected to the heat exchanger 18.

At the auxiliary expeller 44, the solution, the concentration of which has decreased at the auxiliary absorber 16, is sprayed out of the heat transfer pipe of the heat exchanger 46 by the spray device 45. The sprayed solution is heated by the heat source medium flowing in the heat transfer pipe of the heat exchanger 46 and separated into concentrated solution and refrigerant vapor. The concentrated solution is passed through the medium-temperature solution heat exchanger 57 and to the auxiliary absorber 16 by a solution pump 54 which is arranged in the course of a solution pipeline 51. The refrigerant vapor that was separated from the concentrated solution is passed to the condenser 40 via a baffle 52. Heat source medium pipes 47, 48 are connected to the heat exchanger 46 of the auxiliary expeller 44.

The heat source medium flows, for example, successively through the heat exchanger 35 of the high-pressure expeller 33, the heat exchanger 24 of the low-pressure expeller 22 and the heat exchanger 46 of the auxiliary expeller 44. The heat source medium can, as in 2 shown, from a temperature that is above the solution temperature at the outlet of the high pressure expeller 33 (about 90 ° C) to a temperature that is close to the solution temperature at the outlet of the auxiliary expeller 44 (about 60 ° C).

The present exemplary embodiment involves heat exchangers of the falling film type, as in 1 shown, whereby the refrigerant is sprayed on the evaporator 1 and the solution is sprayed by the spray device on the upper section of the individual heat exchangers on the absorber 9, low-pressure expeller 22, high-pressure expeller 33, auxiliary absorber 16 and auxiliary expeller 44.

In the embodiment of the present invention, the gas phase sections of the low-pressure expeller 22 of the single-effect circuit process side and the auxiliary absorber 16 of the auxiliary circuit process side are connected and the gas phase sections of the high-pressure expeller 33 and the capacitor 40 of the single-effect circuit process side and the auxiliary expeller 44 of the auxiliary circuit process side are connected, a combined operation is possible Single effect cycle process and two-stage absorption cycle process possible. In the present embodiment, an aqueous lithium bromide solution is used as the solution (adsorbent), and water is used as the refrigerant.

Next will be with reference to 1 and 2 the design and effect according to the present invention are described.

The solution emerging from the absorber 9 is branched at branch point A after passing through the low-temperature solution heat exchanger 55. This allows, as in 2 shown, solution with a low concentration from the absorber 9 flows into the low-pressure expeller 22. That is, the temperature of the solution flowing into the low-pressure expeller 22 can be reduced by the amount by which the concentration is lower than at the outlet of the high-pressure expeller 33. In this way, a larger difference to the temperature of the driving heat source of the low pressure expeller 22 can be achieved, and the larger difference enables the heat transfer surface to be reduced.

By branching the solution from the absorber 9 at the branch point A, the circulation amount in the high-temperature solution heat exchanger 56 can be reduced compared to the circulation amount from the absorber 9. As a result, together with the circulation amount, the size of the high-temperature liquid heat exchanger 56 can be reduced, the inherent heat loss of the solution can be reduced, and the efficiency of the absorption refrigerator can be increased. In addition, the distribution amount of the solution between the low-pressure expeller 22 and the high-pressure expeller 33 can be regulated by the flow control valve 32 provided in the solution pipeline 31 connected to the low-pressure expeller 22. In this way, the spray amount of the solution on the low-pressure expeller 22 and the high-pressure expeller 33 can be adjusted at will, and when determining the arrangement of the devices, the size of the heat exchangers 24, 35 can be freely set within the spray amount setting range.

The concentrated solution from the low-pressure expeller 22 and the high-pressure expeller 33 is combined at the merging point B, and the solution pump 30 is arranged between the merging point B and the low-temperature solution heat exchanger 55. Taking advantage the pressure level of the solution pump 30 and the solution accumulated in the high-pressure expeller 33 as well as the container pressure difference to the low-pressure expeller 22, the solution can be driven from the high-pressure expeller 33 into the solution pump 30 and using the pressure level of the solution pump 30 and the solution accumulated in the low-pressure expeller 22, the solution is extracted from the Low-pressure expeller 22 is driven into the solution pump 30. In this way, solution can be directed from the high-pressure expeller 33 and from the low-pressure expeller 22 to the absorber 9 at the solution pump 30. That is, a single solution pump 30 can be used for the solution of the low-pressure expeller 22 and the high-pressure expeller 33, which reduces costs and reduces energy consumption.

In the above embodiment, a falling film type heat exchanger configuration has been described, but the present invention is not limited to this embodiment, and from the viewpoint that heat is recovered from a single waste heat source until a low temperature is reached, the effect of the present invention can also be achieved can be achieved in an embodiment with a tube bundle heat exchanger or the like. In the above exemplary embodiment, a flow rate control device was described in which a flow control valve is provided on the flow path of the solution after branching towards the low-pressure expeller, but the present invention is not limited to this embodiment, and an embodiment is also possible in which a flow control valve is provided on the flow path of the Solution is provided towards the high-pressure expeller, or an embodiment in which, instead of a valve, a predetermined suitable flow resistance is provided on the two flow paths downstream of the branching section.

Explanation of the reference numbers

1

Evaporator

2, 10, 17, 23, 34, 45

Spray device

3, 11, 18, 24, 35, 41, 46

Heat exchanger

4, 5

Cold water pipeline

6

Refrigerant pump

7, 50

Refrigerant pipeline

8, 21

separator

9

absorber

12, 13, 19, 20, 42, 43

Cooling water pipeline

14, 29, 30, 54

solution pump

15, 27, 28, 31, 49, 51

Solution pipeline

16

Auxiliary absorber

22

Low pressure expeller

25, 26, 36, 37, 47, 48

Heat source medium pipeline

32

Flow control valve

33

High pressure expeller

39, 52

Baffle

40

capacitor

44

Auxiliary expeller

55

Low temperature solution heat exchanger

56

High temperature solution heat exchanger

57

Medium temperature solution heat exchanger

Claims (7)

Absorption refrigeration machine, comprising an evaporator (1), an absorber (9), a low-pressure expeller (22), a high-pressure expeller (33), an auxiliary absorber (16), an auxiliary expeller (44), a condenser (40) and a solution pump (14) , wherein the gas phase sections of the evaporator (1) and the absorber (9) are connected, the gas phase sections of the low-pressure expeller (22) and the auxiliary absorber (16) are connected, the gas phase sections of the high-pressure expeller (33), the auxiliary expeller (44) and of the condenser (40), a solution pipeline running from the absorber (9) to the high-pressure expeller (33) has a branching section, a solution pipeline is coupled to the branching section and runs to the low-pressure expeller (22), the solution pump (14) is connected to the from Absorber (9) to the branching section solution pipeline is provided and a solution pipeline running from the high pressure expeller (33) to the absorber (9) has a union section which is connected to one of the lower Pressure ejector (22) running solution pipeline is coupled. Absorption chiller Claim 1 , wherein a flow rate control device is provided on the solution pipeline running from the branch section to the low-pressure expeller (22). Absorption chiller Claim 1 or 2 , wherein the evaporator (1), the absorber (9), the low-pressure expeller (22), the high-pressure expeller (33), the auxiliary absorber (16) and the auxiliary expeller (44) have a falling film type heat exchanger. Absorption chiller according to one of the Claims 1 until 3 , a solution pump (14) being provided on the solution pipeline running from the connecting section to the absorber (9). Absorption chiller according to one of the Claims 1 until 4 , wherein a low-temperature solution heat exchanger is provided which carries out a heat exchange between the solution pipeline running from the absorber (9) to the branching section and the solution pipeline running from the combining section to the absorber (9). Absorption chiller according to one of the Claims 1 until 5 , wherein a high-temperature solution heat exchanger is provided, which carries out a heat exchange between the solution pipeline running from the high-pressure expeller (33) to the combining section and the solution pipeline extending from the branching section to the high-pressure expeller (33). Absorption chiller according to one of the Claims 1 until 6 , wherein a medium-temperature solution heat exchanger is provided, which carries out a heat exchange between a solution pipeline running from the auxiliary absorber (16) to the auxiliary expeller (44) and a solution pipeline running from the auxiliary expeller (44) to the auxiliary absorber (16).

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