JPS6125987B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absorption heat pump capable of simultaneously producing high temperature water and cold water.

Conventionally, in an absorption refrigeration cycle, if you wanted to obtain hot water at the same time as cooling, you would use a condenser or a separate dedicated hot water heat exchanger to generate hot water using the heat of steam generated in a generator, for example. When hot water or steam is used as a heat source for heating a solution in a generator, the temperature of the hot water obtained is lower than the temperature of the heat source hot water or steam. When using relatively low-temperature heat source hot water such as heated wastewater in a conventional absorption heat pump, the temperature of the hot water obtained is so low that it has no value.

To solve this problem, we installed a heat pump cycle that includes an absorber and an evaporator on the high-pressure side of an intermediate-pressure generator and a condenser, and a refrigeration cycle that includes an absorber and evaporator on the low-pressure side. Absorption heat pumps have been considered that can simultaneously generate water at a higher temperature than the heat source hot water and cold water at a lower temperature than the cooling water, and which have an extremely simple structure with an integrated structure. This is related to.

That is, to explain an example before the improvement of the present invention as shown in FIG. ) is maintained. A _H is the high pressure stage absorber,
E _H is a high pressure stage evaporator and has a pressure higher than the intermediate pressure, A _L is a low pressure stage absorber, and E _L is a low pressure stage evaporator and has a pressure lower than the intermediate pressure. Regarding the solution side cycle, the low pressure stage absorber A _L is connected to the high pressure stage absorber A _H via the solution pump 1 and intermediate concentration solution pipe 2, and the high pressure stage absorber A _H is generated via the dilute solution pipe 3 and valve 4. The generator G is connected to the low pressure absorber A _L via a concentrated solution pipe 5 and a valve 6. Regarding the refrigerant side cycle, the low pressure evaporator E _L is connected to the high pressure evaporator E _H via a refrigerant pump 7, a refrigerant pipe 8, and valves 9 and 10. Further, a branch pipe 12 having a valve 11 is connected to the refrigerant pipe 8 in order to circulate the refrigerant liquid in the low-pressure stage evaporator E _L. The condenser C and the low pressure evaporator E _L are connected by a pressure reducing valve 29 and a return pipe 30.
A steam pipe 1 that connects the high-pressure stage absorber A _H and the high-pressure stage evaporator E _H as a connection between the solution side and the refrigerant side.
3. Steam pipe 1 connecting generator G and condenser C
4. A steam pipe 15 connecting the low pressure stage absorber A _L and the low pressure stage evaporator E _L is provided. Regarding the relationship between receiving and receiving heat from the outside, hot water pipes 16 as heat sources,
17 are installed in the generator G and high-pressure stage evaporator E _H, respectively, and a valve 1 is installed in the inlet section 18 of the hot water pipe 16.
9 and an inlet pipe 21 with a branch to a three-way valve 20
The outlet portion 22 is connected to the three-way valve 20, and the three-way valve 20 is connected to another three-way valve 23 by a communication pipe 24. One port of the three-way valve 23 is connected to the hot water pipe 17
The other port is connected to the inlet portion 26 of the heat exchanger 26, and the other port thereof is connected to an outlet pipe 28 which continues to the outlet portion 27, and is further connected to the heat exchanger _Xs . The condenser C and the low-pressure stage absorber A _L are equipped with cooling water pipes 31 and 32 through which cooling water flows.
The outlet of the cooling water pipe 31 is connected to a heat exchanger X _W . The high-pressure stage absorber A _H is equipped with a high-temperature water pipe 33 for obtaining the required high-temperature water, and the low-pressure stage evaporator E _L is equipped with a cold water pipe 34 for obtaining the required cold water. As for the control related to high temperature water, a temperature detector 35 is provided at the outlet of the high temperature water pipe 33 and controls the valve 20 via the three-way valve 23 and the signal switch 25.
A temperature detector 36 is provided at the outlet of the cold water pipe 34 and controls the three-way valve 20 via a signal switch 25. 37 and 38 are liquid level detectors that control the valve 10 or the valve 6, respectively. The refrigerant is heated by the heat exchangers X _S and X _W , and the efficiency is increased by effectively utilizing the heat.

To explain the operation and effect of this conventional example, in a heat source hot water system, waste water from a power plant, for example, is supplied from the outside to the inlet pipe 21, the valve 19 is opened, and the three-way valve 20 is closed on the inlet pipe 21 side and the outlet part is 22 and the communication pipe 24 are placed in a state of communication, the valve 25 is closed, and the three-way valve 23
The connecting pipe 24 and the inlet part 26 are placed in communication with each other, and the heat source hot water is discharged to the outside from the outlet pipe 28 via the hot water pipe 16, the connecting pipe 24, and the hot water pipe 17. Of course, hot water can be passed through the hot water pipes 16 and 17 not in series but in parallel, or separately from separate hot water sources. The refrigerant liquid in the low pressure stage evaporator E _L is passed through the refrigerant pipe 8 and valves 9 and 10 by the refrigerant pump 7, and then enters the high pressure stage evaporator E _H into the hot water pipe 1.
It is heated and evaporated by the hot water 7 and enters the high pressure stage absorber A _H via the steam pipe 13. On the other hand, the low pressure stage absorber A _L
From there, the intermediate concentration liquid solution passes through the solution pump 1 and the intermediate concentration solution tube 2, passes through the low pressure stage and high pressure stage heat exchangers X _L and X _H , is heated, and enters the high pressure stage absorber A _H to absorb the above-mentioned refrigerant vapor. At this time, the solution is heated by the absorbed heat to a temperature corresponding to an increase in the boiling point, heating the high temperature water pipe 33, and high temperature water having a higher temperature than the heat source hot water can be obtained. The dilute solution that has absorbed the refrigerant enters the generator G through the dilute solution pipe 3 and the valve, and is heated by the hot water in the hot water pipe 16 to generate steam and concentrate, and the concentrated solution passes through the dilute solution pipe 5, The solution enters the low-pressure stage absorber A _L via the valve 6, is cooled by the cooling water in the cooling water pipe 32, and is sent again by the solution pump 1 to repeat the cycle.

On the other hand, the refrigerant vapor generated in generator G is steam pipe 1
4, reaches the condenser C, is cooled and condensed by the cooling water in the cooling water pipe 31, and enters the low pressure stage evaporator E _L through the return pipe 30 and pressure reducing valve 29, where it is partially evaporated by the heat of the cold water in the cold water pipe 34, and its vapor is partially evaporated. enters the low pressure stage absorber A _L through the steam pipe 15 and is absorbed into the solution. The cold water in the cold water pipe 34 loses heat by evaporation of the refrigerant and becomes low temperature, and cold water at a lower temperature than the cooling water can be obtained from the outlet. A portion of the refrigerant sent by the refrigerant pump 7 enters the branch pipe 12 and returns to the low-pressure stage evaporator E _L to promote evaporation. If there is a load fluctuation or other thermal fluctuation, it is detected by the temperature detectors 35 and 36 installed at the output end, and the three-way valve 2
0 and 23 to control the heat source hot water passing through hot water pipes 16 and 17 to maintain the temperatures of high temperature water and cold water at required values.

However, in the conventional example shown in Fig. 1 as described above, the refrigerant liquid condensed in the condenser C is sent to the low-pressure stage evaporator E _L , from where it is distributed to the necessary locations. The stage evaporator E _L has the lowest refrigerant temperature level in the refrigerant cycle and is the lowest energy point for the refrigerant liquid. For this reason, when the refrigerant liquid is sent from the condenser C to the low-pressure stage evaporator E _L , it first lowers its own liquid temperature and enters a low-energy state, so it flashes and generates refrigerant vapor, which then flows into the low-pressure stage absorber A _L. The load is increasing. This low-temperature refrigerant liquid is pumped to the high-pressure stage evaporator E.
It is preferable to preheat the liquid because it will be pumped to a location where the high temperature energy state of _H is required. However, heating with another heat source results in a loss, so to prevent this, there is a method of recovering waste heat from the system using heat exchangers X _S and X _W as shown in Figure 1. . However, since the temperature on the heating side is low, the heat exchanger becomes large or it is difficult to perform sufficient preheating. Further, since the superheated refrigerant from the generator G is separated from the high-temperature solution, it is led to the condenser C in a considerably high temperature state, and is discarded as it is into the cooling water of the condenser C.

The conventional method has the above-mentioned drawbacks, but the present invention exchanges heat with the high-temperature superheated refrigerant vapor from the generator and the refrigerant liquid sent from the condenser to the high-pressure side evaporator, or the low-pressure side By exchanging heat with the refrigerant liquid sent from the evaporator to the high-pressure side evaporator, it is possible to eliminate the above-mentioned drawbacks of the conventional method and recover as much of the heat radiated to the condenser as possible and use it to preheat the refrigerant liquid. Another object of the present invention is to provide an absorption heat pump that can perform effective preheating with a small heat exchanger since the heating side is at a high temperature.

The present invention provides absorbers, generators, evaporators, condensers,
having a dilute solution heat exchanger and a fluid path connecting them, maintaining the generator and condenser at an intermediate pressure, and at least one stage of absorber and evaporator maintained at a higher pressure; It is equipped with at least one stage of absorber and evaporator maintained at a pressure lower than intermediate pressure, and a heating medium such as hot water is introduced as a heat source to the generator and high-pressure stage evaporator, and cooling water etc. is led to the condenser and low-pressure stage absorber. of the cooling medium, and generate a thermal energy source such as high-temperature water having a higher temperature than the heat source, and generate a cold heat source such as cold water having a lower temperature than the cooling medium such as cooling water, either simultaneously or as necessary. In an absorption heat pump capable of generating one of the two, the refrigerant in the refrigerant path from the generator to the condenser and the condenser and/or
Alternatively, the absorption heat pump is characterized in that a heat exchanger is provided for exchanging heat with the refrigerant introduced from the low-pressure stage evaporator to the high-pressure stage evaporator.

The present invention will be described with reference to the drawings. The example shown in FIG. 2 has roughly the same configuration as that in FIG. 1, and parts with the same symbols have the same names, configurations,
However, the refrigerant liquid from the condenser C is sent directly to the high-pressure stage evaporator E _H via the refrigerant pipe 8 by the refrigerant pump 39, and to the low-pressure stage evaporator E _L due to gravity and pressure difference. Flow rate control of refrigerant pump 39, valve 9 or 10
By controlling the flow rate, the ratio of refrigerant liquid distribution to the high-pressure stage evaporator E _H and the low-pressure stage evaporator E _L can be changed to minimize flash losses in the evaporator.

In addition, the refrigerant liquid supplied from the condenser C to the high-pressure side evaporator E _H by the refrigerant pump 39 is exchanged with high-temperature superheated refrigerant vapor supplied from the generator G to the condenser C in a heat exchanger 44. The exhaust heat that would otherwise be wasted in the cooling water is recovered and the heat exchange rate is improved. Since this steam is at a high temperature, the heat exchanger 44 is small and effective heat recovery is performed. FIG. 3 shows only the refrigerant cycle as a model.

FIG. 4 shows another embodiment in which the heat exchanger 44 in FIG. 3 is provided within the condenser C.

FIG. 5 shows another embodiment, in which the low pressure stage evaporator E _L
The refrigerant pump 7 distributes the required amount of refrigerant liquid from the heat exchanger 44 to the high-pressure stage evaporator _EH .
In addition, a heat exchanger 45 is used to recover exhaust heat,
The refrigerant can be preheated without using any other heat source, improving thermal efficiency. This refrigerant pump may also be used as a spray pump to uniformly spread the refrigerant liquid onto the evaporator tube.

FIG. 6 shows another embodiment in which the heat exchanger 44 in FIG. 5 is installed in the condenser C.

Regarding the above example, in either case of the high-pressure stage evaporator E _H or the low-pressure stage evaporator E _L , a refrigerant pump 7 for spraying and a spray pipe 46 are installed as necessary to improve heat transfer in the tube as shown in Fig. 7. Spraying can be performed by circulating the refrigerant liquid.

The present invention provides an absorption heat pump that does not require energy from other heat sources, effectively recovers the thermal energy wasted in the condenser, and downsizes the heat exchanger, and has high operational efficiency. It has an extremely large effect in terms of practical use and energy saving.

[Brief explanation of the drawing]

Figure 1 is a flow sheet of a conventional example;
The figure is a flow sheet of an embodiment of the present invention, and FIGS. 3 to 7 are flow sheets of refrigerant cycles of different embodiments of the present invention. G... Generator, C... Condenser, A _H ... High pressure stage absorber, A _L ... Low pressure stage absorber, E _H ... High pressure stage evaporator, E _L ... Low pressure stage evaporator, X _H ...High pressure stage heat exchanger, X _L ...Low pressure stage heat exchanger, 1...Solution pump, 2...Intermediate concentration solution tube, 3...Dilute solution tube,
4, 6, 9, 10, 11, 19... Valve, 5... Concentrated solution tube, 7, 39... Refrigerant pump, 8, 40, 4
1,42...refrigerant pipe, 12...branch pipe, 13,1
4, 15... Steam pipe, 16, 17... Hot water pipe, 1
8, 26...Inlet section, 20, 23...Three-way valve, 2
1... Inlet pipe, 22, 27... Outlet section, 24...
Communication pipe, 28... Outlet pipe, 29... Pressure reducing valve, 30
... Return pipe, 31, 32 ... Cooling water pipe, 33 ...
High temperature water pipe, 34... Cold water pipe, 35, 36... Temperature detector, 37, 38... Liquid level detector, 39... Refrigerant pump, 44, 45... Heat exchanger, 46... Spray pipe.

Claims (1)

[Scope of Claims] 1. It has an absorber, a generator, an evaporator, a condenser, a dilute solution heat exchanger, and a fluid path connecting these, and maintains the generator and the condenser at an intermediate pressure. at least one stage of absorber and evaporator held at a high pressure and at least one stage of absorber and evaporator held at a pressure lower than said intermediate pressure; A heating medium such as cooling water is introduced into the condenser and a low-pressure stage absorber, and a cooling medium such as cooling water is introduced into the condenser and a low-pressure stage absorber to generate a thermal energy source such as high-temperature water that is higher in temperature than the heat source, and a cooling medium such as cooling water is In an absorption heat pump that is capable of generating a cold heat source such as low-temperature cold water at the same time or generating either one of them as necessary, the refrigerant path from the generator to the condenser is An absorption heat pump characterized in that a heat exchanger is provided for exchanging heat between a refrigerant and a refrigerant introduced from the condenser and/or the low-pressure stage evaporator to the high-pressure stage evaporator.