JPH1030854A - Absorption heat pump - Google Patents

Abstract

(57) [Problem] To remove water contained in refrigerant vapor in an absorption heat pump using water-ammonia as a working medium,
Improve the performance of the rectifier used to increase the purity of the refrigerant and improve the COP. SOLUTION: A regeneration unit 31, a condenser 32, an evaporator 35, a refrigerant vapor evaporated by the evaporator 35 and a weak solution generated by the regeneration unit 31 are introduced, and the weak solution absorbs the refrigerant vapor. An absorption unit 36 for producing a strong solution;
A solution pump 37 which pressurizes the strong solution generated by the absorption unit 36 and introduces the solution into the regeneration unit 31 via the absorption unit.
In the absorption heat pump including the above, the regeneration unit 31 is configured to include a decomposer 42 provided at the upper part thereof for cooling the steam, and a flow control valve 59 is provided in an outlet pipe 61 of the solution pump 37. A branch strong solution pipe 62 was provided, and the downstream end of the branch strong solution pipe 62 was arranged so as to open above the decomposer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption heat pump, and more particularly to an absorption heat pump including a regeneration unit having a rectifier and a method of operating the same.

[0002]

2. Description of the Related Art FIG. 3 shows a configuration of a general ammonia absorption heat pump having a GAX cycle conventionally known. The absorption type heat pump shown in FIG.
1, condenser 32, refrigerant heat exchanger 33, expansion valve 34, evaporator 35, absorption unit 36, solution pump 37, pressure reducing valve 5
7 are included.

[0003] The regeneration unit 31 has a vertical regeneration vessel 38.
Are provided in the order from the bottom, a regeneration heat input device 39, a weak solution heat exchanger 40, a rectifier 41 composed of a recovery stage 41a and a concentration stage 41b, and a decomposer 42 forming a heat exchange channel. It is formed. The bottom of the regeneration vessel 38 is connected to the inlet side of the heat exchanger 40 by a pipe. By the regeneration unit 31, the strong solution 55 supplied from the solution pump 37 is separated into the refrigerant vapor 44 taken out from the top of the regeneration vessel 38 and the weak solution 56 collected at the bottom of the regeneration vessel 38.

[0004] The absorption unit 36 is provided with a heat exchange flow path that forms a spraying device 51 disposed at the top and an absorption heat recovery heat exchange section (that is, an absorption regeneration heat exchanger) 52 disposed below, and an absorption heat recovery heat exchanger. A dispersing device 51a disposed on the top including a heat exchange flow path forming an absorbing / radiating portion 53 disposed below the exchanging portion 52 and an absorbing container 50 containing the same, and an absorbing / radiating disposed below the exchanging device 51a. And a low-pressure side absorber 50a internally provided with a heat exchange channel forming the part 53. The spraying device 51 is connected to the outlet of the heat exchanger 40 via a pressure reducing valve 57, and the inlet of the absorption heat recovery heat exchanger 52 is connected to the outlet of the decompressor 42. The suction side of the solution pump 37 is connected to the bottom of the absorption container 50, and the discharge side of the solution pump 37 is connected to the input side of the decompressor 42. The outlet side of the absorption heat recovery heat exchange section 52 is connected between the recovery stage 41a and the concentration stage 41b of the rectifier 41.

The condenser 32 includes a heat exchange coil 45 through which a cooling fluid flows. The condenser 32 has a top connected to the top of the regeneration unit 31 and a bottom connected to the inlet of the refrigerant-side heat exchanger 33 on the heating side. . The outlet side of the heated fluid channel of the refrigerant heat exchanger 33 is connected to the bottom of the absorption container 50.

The evaporator 35 is provided with a refrigerant dispersing device 47 disposed at the top and a heat exchange coil 48 disposed below the refrigerant dispersing device 47 and through which a cooling fluid flows. The refrigerant heat exchanger 33 is connected to the outlet side of the heating-side fluid flow path via an expansion valve 34. The evaporator 35 is also connected to a side of the refrigerant heat exchanger 33 on which the heated fluid path enters.

[0007] The decomposer 42 of the regenerating unit 31 cools the vapor of the solution rising from below, condenses a part of the vapor, and flows it down to the rectifier 41, where the solution of the solution rising from below is cooled. It is in contact with steam (a mixture of steam of ammonia, which is a refrigerant, and water), and serves to increase the refrigerant purity of the steam.

In a highly efficient GAX cycle, a solution having a high ammonia concentration (a strong solution) passing through the heat exchanger is boiled in an absorption heat recovery heat exchange section 52 to convert a weak solution flowing outside the heat exchanger into a strong solution. Heat recovery. But,
In this case, the maximum temperature in the regenerator increases, and accordingly, the amount of moisture in the steam generated in the regenerator increases. Therefore, the load applied to the rectifier 41 for increasing the purity of the refrigerant vapor extracted from the regeneration unit 31 increases,
A large rectifier is required.

FIG. 4 shows an example of another rectification method called a cold solution field disclosed in Japanese Patent Application Laid-Open No. 5-187736. According to this method, a part of the strong solution pressurized by the solution pump 11 is branched and introduced into the top of a rectifier 19 provided separately from the regenerator. The introduced strong solution comes into direct contact with the refrigerant vapor rising from below, and the solvent vapor (water vapor) in the refrigerant vapor
To improve the purity of the refrigerant vapor. The heat generated by the rectification is recovered in a strong solution.

[0010]

According to the rectification method shown in FIG. 3, the vapor that rises outside is condensed with a strong solution flowing in the decomposer 42, and the condensed solution is dropped and refluxed in the rectifier 41. However, in order to obtain an absorption heat pump having a high coefficient of performance (COP), a rectifier having sufficient performance and size is required, and a solution that is condensed and refluxed by the decomposer 42 is required. Had to be reduced. However, when the amount of the refluxing solution is reduced, it is difficult to ensure sufficient gas-liquid contact in the rectifier, and there is a problem that a low-purity refrigerant is produced, resulting in a low coefficient of performance.

On the other hand, according to the system shown in FIG. 4, the steam is brought into direct contact with a cold supercooled solution (ie, a strong solution pressurized and introduced by the solution pump 11), so that the rectification effect is high. The temperature rises while the strong solution pressurized at 11 reaches the rectifying section, and in order to obtain a sufficient effect, the amount of the solution branched toward the rectifier 19 at the outlet side of the solution pump 11 must be reduced. It had to be set to tolerate. As a result, the amount of heat that can be recovered by the strong solution from the absorber is reduced, and the COP does not improve as expected even when the GAX cycle is performed.

An object of the present invention is to improve the performance of a rectification device used for removing the water contained in the generated ammonia vapor and improving the purity of the refrigerant in a heat pump using water-ammonia as a working medium, To improve.

[0013]

The object of the present invention is to introduce a strong solution having a high refrigerant concentration by absorbing a refrigerant into an absorbent and separating the strong solution into refrigerant vapor and a weak solution having a low refrigerant concentration. A condenser 32 that cools the refrigerant vapor generated by the regeneration unit 31 into a liquid refrigerant,
The liquid refrigerant generated by the condenser is introduced through an expansion valve 34, and the evaporator 35 evaporates the liquid refrigerant by heat exchange with a heat medium. An absorption unit 36 for introducing the weak solution generated in the unit 31 to absorb the refrigerant vapor into the weak solution to generate a strong solution, and pressurizing the strong solution generated by the absorption unit 36 to perform the regeneration through the absorption unit. In the absorption heat pump including the solution pump 37 introduced into the unit 31, the regeneration unit 31 is configured to include a decomposer 42 installed in an upper part thereof for cooling steam, and an outlet pipe of the solution pump 37. This is achieved by providing a branch pipe 62 with a flow control means 59 interposed in 61 and disposing a downstream end of the branch pipe 62 so as to open above the decomposer.

Before the strong solution pressurized by the solution pump 37 is guided to the absorption unit, the strong solution flows through the decompressor 42 provided in the regeneration unit 31 via the outlet pipe 61 and then to the absorption unit 36. It is desirable to configure as follows.

The above-mentioned problem is also solved by introducing a strong solution having a high refrigerant concentration obtained by absorbing a refrigerant into an absorbent into a regeneration unit 31 and separating the introduced strong solution into a vapor and a weak solution having a low refrigerant concentration. Generated, a part of the vapor is cooled and liquefied by a decompressor built in the upper part of the regeneration unit 31 and dropped downward, and the refrigerant vapor generated by the regeneration unit 31 is cooled by the condenser 32 to become a liquid refrigerant. This liquid refrigerant is introduced into an evaporator 35 through an expansion valve 34 and evaporated by heat exchange with a heat medium, and the evaporated refrigerant vapor is absorbed into a weak solution generated by the regeneration unit 31 to absorb heat and recover heat. The strong solution is absorbed on the heat transfer surface of the heat exchange flow path to form a strong solution, and the strong solution is pressurized and passed through the flow path in the decomposer to remove the heat of the outside steam, and then heat Flow through the exchange channel to recover the heat of the weak solution at the time of absorption into the strong solution. Play strong solution after the heat recovery unit 3
In the method of operating an absorption heat pump that repeats the above-described cycle by introducing the above-described method into the first step, a part of the strongly pressurized solution is guided to the top of the regenerating unit 31 and sprayed on the outer surface of the decomposer. Is also achieved.

It is desirable to use ammonia as the refrigerant and water as the absorbent (solvent).

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The illustrated embodiment is an example of an absorption heat pump using ammonia as a refrigerant and an absorbent (solvent) as water. The absorption heat pump of this embodiment is different from the absorption heat pump shown in FIG. 3 in two points, that is, the configuration of the regeneration unit 31 and the connection destination of the discharge-side pipe of the solution pump 37. Other configurations are the same as those of the absorption heat pump shown in FIG. 3, and thus the same reference numerals are given and the description is omitted.

The regenerating unit 31 of the present embodiment includes a regenerating heat input device 3 inside a vertical regenerating vessel 38 in order from the bottom.
9. Heat exchanger 40 for weak solution, recovery stage 41a and liquid tray 4
It is formed by providing a rectifier 41 comprising 1c and a concentration stage 41b, a separator 42 forming a heat exchange channel, and a branched solution spraying device 60. The bottom of the regeneration vessel 38 is connected to the inlet side of the heat exchanger 40 by a pipe, and the outlet side of the heat exchanger 40 is connected to the spraying device 51 of the absorption unit 36 via a pressure reducing valve 57.
By the regeneration unit 31, the strong solution supplied from the solution pump 37 is separated into the refrigerant vapor 44 extracted from the top of the regeneration vessel 38 and the weak solution 56 collected at the bottom of the regeneration vessel 38.

The suction side of the solution pump 37 is connected to the bottom of the absorption container 50, and the discharge side of the solution pump 37 is connected to the inlet of the decomposer 42 by a strong solution pipe 61 which is the outlet pipe of the solution pump. A strong solution pipe 62 is provided as a branch pipe having a flow control valve 59 serving as a flow control means, which branches into the strong solution pipe 61. The downstream end of the strong solution pipe 62 is connected to the branch solution. It is connected to the spraying device 60. That is, a part of the strong solution pressurized by the solution pump 37 is guided to the branch solution spraying device 60 after the flow rate is adjusted by the flow rate adjusting valve 59, and the branched solution is sprayed from the branch solution spraying device 60 onto the outer surface of the decompressor 42. Is to be sprayed.

The operation of the embodiment configured as described above will be described below. The condenser 32 introduces the refrigerant vapor 44 generated by the regeneration unit 31 and cools and condenses the refrigerant with the cooling fluid flowing through the heat exchange coil 45. Condenser 3
The liquid refrigerant 46 condensed by 2 is depressurized by the expansion valve 34 via the heating fluid side flow path of the refrigerant heat exchanger 33. The refrigerant decompressed by the expansion valve 34 is sprayed onto the heat exchange coil 48 from a refrigerant spraying device 47 provided at the top of the evaporator 35. The sprayed refrigerant takes off the heat of the cooling fluid flowing through the heat exchange coil 48 and evaporates, and the refrigerant vapor 49 passes through the fluid passage to be heated of the refrigerant heat exchanger 33 and passes through the absorption vessel 5.
0 is introduced at the bottom. The refrigerant vapor introduced into the bottom of the absorption container 50 rises outside the heat exchange flow path forming the absorption / radiation section 53 and outside the heat exchange flow path forming the absorption heat recovery heat exchange section 52. In the process, the refrigerant vapor is absorbed by the weak solution sprayed from the weak solution spraying device 51 on the heat transfer surfaces of the heat exchange channels, and the sprayed weak solution increases the refrigerant concentration to become a strong solution, It collects at the bottom of the absorption container 50. Absorbed heat generated by the absorption of the refrigerant vapor is continuously extracted by the cooling fluid flowing in the heat exchange channel in the absorption / radiation section 53, and is absorbed in the heat exchange channel in the absorption heat recovery heat exchange section 52. It is continuously collected in a strong solution flowing inside the, and is used as a part of heat required for regeneration.

The strong solution collected at the bottom of the absorption container 50 is, for example, a supercooled aqueous ammonia solution having a pressure of 4 to 5 kg / cm ² and a concentration of about 50%. Reproduction unit 31 via tube 61
To the divider 42. The strong solution guided to the decomposer 42 takes heat of the fluid flowing outside the decomposer 42 while passing through the decomposer 42 and is heated, and the heated strong solution is absorbed by the absorption unit 36. The recovered heat exchange section 52 is introduced into the heat exchange channel from the lower entrance. The strong solution 55 which has recovered the heat of the fluid outside the heat exchange channel while passing through the absorption heat recovery heat exchange section 52 is introduced into the rectifier 41 of the regeneration unit 31. More specifically, the absorption heat recovery heat exchange section 52
In the above, the strong solution 55 that has been boiled by the absorption heat generated by the absorption of the refrigerant vapor and has become a two-phase flow of gas and liquid flows from the upper outlet of the absorption heat recovery heat exchange unit 52 to the middle stage of the rectifier 41 of the regeneration unit 31 (Between the concentration stage 41b and the recovery stage 41a) and sent to the liquid receiving tray 41c. The two-phase strong solution 55 introduced into the liquid receiving tray 41c of the rectifier 41 is separated into a refrigerant vapor and a solution.

The remainder of the strong solution pressurized by the solution pump 37 (the amount guided to the strong solution branch pipe 62) is guided to the branch solution spraying device 60 and sprayed downward from the branch solution spraying device 60. . Since this strong solution is in a supercooled state, immediately after being sprayed, it absorbs steam and rises in temperature, becoming saturated. The saturated solution falls on the decomposer 42 and absorbs steam while being deprived of heat by the strong solution flowing through the decomposer 42. That is, the decompressor 42 functions like an absorber. The solution that has passed through the outer surface of the separator 42 flows down to the concentration stage 41 b of the rectifier 41.

On the other hand, the separated refrigerant vapor is supplied to the rectifier 4
In the course of ascending the one concentration stage 41b, the strong solution flowing down comes into gas-liquid contact to increase the concentration of the refrigerant, and further rises to reach the surface of the decomposer 42. The vapor is supplied to the condenser 32 after the vapor is further condensed and removed by heat exchange with a strong low-temperature solution passed through the condenser 42 to increase the concentration of the refrigerant vapor. On the other hand, the separated solution decreases in refrigerant concentration in the process of descending the recovery stage 41a of the rectifier 41, becomes a weak solution when passing through the weak solution heat exchanger 40, and accumulates at the bottom of the regeneration vessel 38. The weak solution 56 has a pressure of, for example, 20 kg / c.
It is an aqueous ammonia solution of 5 to 10% in m ² , and the steam generated from this weak solution by heating by the regeneration heat input device 39 contains 40 to 50% of steam. The weak solution 56 is supplied to the weak solution spraying device 51 provided in the absorption unit 36 through the heat exchanger 40 and the pressure reducing valve 57. An equilibrium but relatively low-temperature reflux liquid is supplied to the recovery stage 41a of the rectifier 41 through the concentration stage 41b. As a result, the rectification efficiency is increased, and a sufficient effect is obtained even with a relatively small rectifier. At the same time, the branching flow rate is relatively small. Therefore, most of the strong solution pressurized by the solution pump 37 is introduced into the absorber, and the absorption heat is recovered, so that the COP can be increased. According to the tests by the inventors, the ratio of the strong solution that branches off is appropriately about 10 to 20% of the amount discharged by the solution pump. This amount of branching is larger than the reflux flow rate in the case of the reflux system (the system of FIG. 3) in which the condensate is condensed and dropped by the condensing device, and is not so large as to cause a problem in gas-liquid contact in the rectifier 41.

In the embodiment shown in FIG. 1, the branch solution spraying device is provided independently above the decomposer 42, but it is not always necessary to provide the device separately from the decomposer 42. For example, the decomposer 42 is composed of a plurality of horizontally wound coils, a number of small holes directed downward are provided in the uppermost coil, and a strong solution is applied to the lower coil from the small holes. The same effect can be obtained even if it is configured to spray. In short,
Not only is the solution obtained by condensing and liquefying the vapor in the condenser 42 being dropped downward to perform gas-liquid contact in the rectifier, but also by directly spraying a supercooled strong solution, In addition to ensuring sufficient gas-liquid contact in the rectifier, the spray liquid is cooled on the separator 42 to have an absorbing function.

In the second embodiment of the present invention shown in FIG. 2, the cooling fluid flowing through the decomposer 42 is replaced with an external fluid, for example, cooling water, instead of the strong solution shown in FIG. is there. In this case, the strong solution pipe 61 is connected to the entrance side of the absorption heat recovery heat exchange unit 52 instead of being connected to the decomposer 42,
A cooling water pipe is connected to an outlet and an inlet of the decompressor 42. Most of the strong solution pressurized by the solution pump 37 is introduced into the absorption heat recovery heat exchange section 52 through the strong solution pipe 61, and the rest is passed through the flow control valve 59 as in the case of the first embodiment. A branching solution spraying device 60 through a branching strong solution pipe 62
It is led to. In this embodiment, the same effects as those of the first embodiment can be obtained.

[0026]

According to the present invention, a sufficient gas-liquid contact area in the rectifier is ensured to exert the rectification effect, and the strong solution necessary for heat recovery is supplied to the absorber. The COP of the absorption heat pump can be improved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a configuration of a main part of a first embodiment of the present invention.

FIG. 2 is a system diagram showing a configuration of a main part of a second embodiment of the present invention.

FIG. 3 is a system diagram showing a configuration of a main part of an example of the related art.

FIG. 4 is a system diagram showing another configuration of the main part of the prior art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Solution pump 12 Absorber 16 Generator 19 Rectifier 31 Regeneration unit 32 Condenser 33 Refrigerant heat exchanger 34 Expansion valve 35 Evaporator 36 Absorption unit 37 Solution pump 38 Regeneration container 39 Regeneration heat input device 40 Heat exchange of weak solution Container 41 Rectifier 41a Recovery stage 41b Concentration stage 41c Liquid tray 42 Decompressor 44 Refrigerant vapor 45 Heat exchange coil 46 Liquid refrigerant 47 Refrigerant spraying device 48 Heat exchange coil 49 Refrigerant vapor 50 Absorption container 51 Spraying device 52 Absorption heat recovery heat Exchange unit 53 Absorption / radiation unit 55 Strong solution 56 Weak solution 57 Pressure reducing valve 58 Weak solution 60 Branch solution spraying device 61 Strong solution pipe 62 Branch strong solution pipe

Claims (4)

[Claims] 1. A regenerating unit having a rectifier for introducing a strong solution having a high refrigerant concentration formed by absorbing a refrigerant into an absorbent and separating and generating the strong solution into refrigerant vapor and a weak solution having a low refrigerant concentration. And a condenser that cools the refrigerant vapor generated by the regeneration unit to become a liquid refrigerant, and introduces the liquid refrigerant generated by the condenser through an expansion valve, and exchanges the liquid by heat exchange with a heat medium. An evaporator for evaporating the refrigerant, an absorption unit for introducing the refrigerant vapor evaporated in the evaporator and the weak solution generated in the regeneration unit, absorbing the refrigerant vapor in the weak solution to generate a strong solution, and A solution pump that pressurizes the strong solution generated by the absorption unit and introduces the solution into the regeneration unit via the absorption unit. Including Configured, the branch pipe is interposed a flow control means on the outlet pipe of the solution pump is provided, the downstream end of the branch pipe, absorption heat pump, characterized in that arranged by the opening in the dephlegmator upward. 2. A strong solution pressurized by a solution pump is configured to flow through an outlet pipe through a decomposer built in a regeneration unit, and then guided to an absorption unit. The absorption heat pump according to claim 1. 3. A branch solution spraying device for spraying a supplied solution downward is provided above the decomposer, and a downstream end of the branch pipe is connected to the branch solution spraying device. 3. The absorption heat pump according to 1 or 2. 4. A strong solution having a high refrigerant concentration, which is obtained by absorbing a refrigerant into an absorbent, is introduced into a regeneration unit, and the introduced strong solution is separated and generated into a vapor and a weak solution having a low refrigerant concentration. Is cooled and liquefied by a decompressor built in the upper part of the regenerating unit and dropped downward, and the refrigerant vapor generated by the regenerating unit is cooled by a condenser to become a liquid refrigerant, and this liquid refrigerant is expanded by an expansion valve. Introduced into the evaporator and evaporated by heat exchange with the heat medium, and the evaporated refrigerant vapor is absorbed into the weak solution generated by the regeneration unit on the heat transfer surface of the heat exchange flow path forming an absorption heat recovery heat exchange unit. To generate a strong solution, pressurize this strong solution to pass through the flow path in the decomposer and take away the heat of the outside steam, and then flow through the heat exchange flow path to absorb the strong solution. The heat of the weak solution is recovered to the strong solution, and the strong solution after the heat recovery is introduced into the regeneration unit to recover the heat. The method of operating an absorption heat pump in which a cycle is repeated, wherein a part of the pressurized strong solution is guided to a top of a regeneration unit, and is sprayed on an outer surface of the decomposer. how to drive.