JPH02302565A - Complex freezing device - Google Patents

Abstract

PURPOSE:To get a complex freezing device having a high coefficient of performance even in case of a low cold heat source temperature to be utilized by a method wherein a vapor compressive type freezer and a thermal driving freezer are made complex and a cold heat generated by an evaporator of the vapor compressive type freezer is used as a cooling source for a cooled element of the thermal driving type freezer. CONSTITUTION:In case of an ammonia absorptive type freezer having a complex ammonia absortive type freezer and a vapor compressive type freezer, for example, dilute solution flowing from an absorbing device 13 into a generating device 8 is heated by a flowing driving heat source to generate ammonia. Water vapor is separated by a purifying device 10, only ammonia vapor flows in the condensor 9, the vapor is cooled by a cold heat generated by the evaporator 1 to become liquid. The liquid flows into the evaporator 12, is heated by the flowing fluid and evaporates. This evaporation heat is utilized as a cold heat. In turn, rich solution with ammonia discharged by the generater 8 is heat exchanged with a dilute solution pipe with a heat recoverying heat exchanger 14, its temperature is decreased, the solution flows into an absorbing device 13 to absorb vapor from the evaporator 12 to become a low concentration solution and then the solution is sent again to the generator 8. The heat generated through this absorption at this time is taken away by liquid from the evaporator 1.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a refrigeration device that generates low-temperature heat necessary for, for example, freezing food.

[Conventional technology]

FIG. 4 shows the configuration of a conventional vapor compression type refrigeration a (two-stage compression). In the figure, 1 is an evaporator, 2 is a low-stage compressor, 3 is an intercooler, 4 is a high-stage compressor, and 5 is a condenser, which are connected in this order by piping. Here, low stage compressor 2
The discharge pipe of the high-stage compressor 4 and the suction pipe of the high-stage compressor 4 are connected to the outside of the heat exchanger tube of the intercooler 3. The pipe exiting the condenser 5 is branched, and one of the branches is connected to the heat transfer tube of the intercooler 3, and the other is connected to the outside of the pipe of the intercooler 3 via the first pressure reducing device 6. Furthermore, the heat exchanger tube side of the intercooler 3 is connected to the evaporator 1 via the second pressure reducing device 7, and constitutes a two-stage compression refrigeration cycle of the refrigerator. Next, the operation will be explained. Figure 5 shows the state at each point in the refrigeration cycle shown in Figure 4 with pressure - enthalpy <
It is expressed as a ph> diagram, and the symbols a to h in the diagram are the fourth
This corresponds to each point indicated by the same reference numeral in the figure. The refrigerant vapor (state a) after being evaporated in the evaporator 1 is sucked into the low stage compressor 2 and compressed to an intermediate pressure Pm to become the state b. The superheated refrigerant vapor in the state is transferred to the intercooler 31.
This flows in. In the intercooler 3, high pressure liquid (like B e )
Bypassing a part of the pressure Pm by the first pressure reducing device 6
The pressure is reduced to 100% and the water is allowed to flow in. The state of this refrigerant is indicated by f. The refrigerant in state f evaporates in the intercooler 3 to cool most of the refrigerant liquid (state e) from the condenser 5, and also evaporates into superheated refrigerant vapor in state e discharged from the low stage compressor 2. They are mixed to form state C, and both are sucked into the high-stage compressor 4, where they are compressed to form state d. This superheated steam is cooled by cooling water obtained from a cooling tower (not shown), and is condensed in a condenser 5 to become a high-pressure liquid in state e. Most of this liquid is cooled in the intercooler 3 to the state g as described above, and flows into the evaporator 1 through the second pressure reducing device 7 with the pressure reduced to the evaporation pressure PL. The refrigerant is evaporated in the evaporator 1, changing from the state Bh to the state a, and the refrigeration cycle is repeated. The heat of evaporation at this time is used for things such as freezing.

[Problem to be solved by the invention]

Since the conventional refrigeration apparatus is configured as described above, there has been a problem that when the evaporation temperature in the evaporation H1 becomes low, the coefficient of performance (refrigeration capacity/compressor input) of the refrigeration cycle decreases. This invention was made to solve the above-mentioned problems, and an object thereof is to obtain a composite refrigeration system with a high coefficient of performance even when the temperature of the cold heat source (evaporation temperature) used is low.

[Means to solve the problem]

The combined refrigeration system according to the present invention combines a vapor compression refrigerator and a thermally driven refrigerator, and transfers cold heat obtained from the evaporator of the vapor compression refrigerator to a cooled element of the thermally driven refrigerator, such as a condenser. It is designed to be used as a cooling source for an absorber.

[For use]

The combined refrigeration system of the present invention combines a vapor compression refrigerator and a thermally driven refrigerator, and uses the cold heat obtained by the evaporator of the vapor compression refrigerator as a cooling source for the thermally driven refrigerator. The evaporation temperature of the one-atm compression refrigeration cycle is higher than that of the conventional one, and the condensing pressure and drive heat source temperature of the thermally driven refrigerator are lower than those of the conventional thermally driven refrigerator.

【Example】

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, numerals 1 to 7 indicate equipment that is the same as or corresponds to the conventional apparatus shown in FIG. 4, and constitutes a refrigeration cycle of a vapor compression refrigerator. Reference numeral 8 denotes a generator, and inside the generator 8 there is provided a heat exchanger through which a heat source for driving the refrigerator flows inside the tube. Further, the generator 8 is connected to the condenser 9 via the rectifier 10 through the piping described above. Further, the condenser 9 is connected to an evaporator 12 via a third pressure reducing device 11, and the evaporator 12 communicates with an absorber 13 through a steam pipe. Also, the evaporator 12
has a heat exchanger for extracting the cold heat to be used. On the other hand, the generator 8 and the absorber 13 include a concentrated solution pipe through which the concentrated solution in the generator 8 flows from the generator 8 to the absorber 13;
They are interconnected by an F5 solution pipe through which dilute solution flows from the absorber 13 to the generator 8, and these solutions exchange heat in a heat recovery heat exchanger 14. These generators8. Condenser9. Rectifier 10. Third pressure reducing device 11° evaporator 12. Absorber 13. The heat recovery heat exchanger 14 and piping constitute a refrigeration cycle of the thermally driven refrigerator. Further, the heat exchangers provided in the condenser 9 and the absorber 13 are connected together with the heat exchanger in the evaporator 1 in an annular manner through piping. Next, the operation will be explained. FIG. 2 depicts the refrigeration cycle of the heat-driven refrigerator shown in FIG. 1 on a pressure-temperature-concentration diagram. Here, the refrigerant is NH3 (ammonia), and the absorption liquid is an ammonia aqueous solution (NH:l' H2
A refrigerator that combines an ammonia absorption refrigerator using 0) and a vapor compression refrigerator will be described. The operation of the vapor compression refrigerator is the same as the conventional device described with reference to FIG. In the ammonia absorption refrigerator, the dilute solution (concentration x 1) that flows from the absorber 3 through the dilute solution pipe into the generator 8 is heated by the driving heat source flowing through the heat exchanger in the generator 8 and vaporized into ammonia vapor. occurs. Since this steam contains a small amount of water vapor, a rectifier 10 is usually provided to separate the water vapor and allow only ammonia vapor to flow to the condenser 9. In the condenser 9, the cold heat obtained in the evaporator 1 passes through the heat exchanger in the absorber 13 and is given to the heat exchanger in the condenser 9, and the refrigerant is cooled to the temperature Tc shown in FIG. The liquid becomes a state of pressure Pc. This ammonia solution is
After being depressurized by the depressurizer 11, it flows into the evaporator 12, where it is heated by the fluid flowing in the heat exchanger and evaporates (temperature T!, pressure PE). This heat of evaporation is used as cooling energy. On the other hand, the concentrated solution (temperature TG) whose concentration has become x2 by releasing ammonia in the generator 8 flows into the absorber 13 through the heat recovery heat exchanger 14 . In heat recovery heat exchange H14, the temperature of the concentrated solution is lowered by exchanging heat with the dilute solution tube flowing from the absorber 13 to the generator 8. In addition, the absorber 13
The concentrated solution that has flowed into the evaporator 12 absorbs the vapor from the evaporator 12, becomes concentrated by 1, and is sent to the generator 8 again. The heat generated by absorption at this time is absorbed by the liquid sent from the evaporator 1 in a heat exchanger within the absorber 13. Therefore, the cold heat obtained in the evaporator 1 is absorbed by the absorber 13, and the heat is absorbed in the condenser 9.
It is used to remove the heat of condensation. As described above, in the conventional refrigeration system, the temperature TE of the refrigeration system of the present invention is obtained directly from the evaporator 1 as the saturation temperature corresponding to the pressure P shown in FIG. In the device, the pressure PL in the evaporator I has a value corresponding to the temperature level TA in FIG. Therefore, the coefficient of performance of a vapor compression refrigerator is significantly improved by increasing the evaporation temperature. In the above embodiment, the heat source of the generator 8 was introduced from another process, but the heat of condensation released from the condenser 5 of the vapor compression refrigerator may be used as the heat source. Further, in the above embodiment, NH3H2O was explained as the working medium of the thermally driven refrigerator, but the working medium is not limited to this medium, and methylamine (CHx N Hz
)-Calcium chloride (CaC1□) and other media can provide similar effects. Further, in the above embodiment, a two-stage compression refrigeration cycle was used as the vapor compression refrigerator, but if the evaporation temperature is high, a single-stage compression refrigeration cycle may be used.

【Effect of the invention】

As described above, in the combined refrigeration system according to the present invention, the evaporation temperature of the vapor compression type refrigeration system is made higher than that of the conventional vapor compression type, and this heat of evaporation is used as a cooling source for the condenser of the heat-driven refrigerator. Since the low-temperature heat to be used is obtained from the evaporator of the heat-driven refrigerator, the coefficient of performance of the vapor compression refrigerator is significantly improved, and the coefficient of performance of the combined refrigeration system is also greater than that of the conventional vapor compression system. This has the effect of enabling highly efficient operation.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing a combined refrigeration system according to an embodiment of the present invention, FIG. 2 is an equilibrium diagram showing the operating state of the refrigeration system shown in FIG. FIG. 4 is a system diagram showing a combined refrigeration system, FIG. 4 is a system diagram of a conventional vapor compression refrigerator, and FIG. 5 is an equilibrium diagram showing the operating state of the refrigerator shown in FIG. ■ is an evaporator, 2 is a low stage compressor, 3 is an intercooler, 4 is a high stage compressor, 5 is a condenser, 8 is a generator, 9 is a condenser, 10
1 is a rectifier, 11 is a third pressure reducing device, 12 is a generator, 13 is an absorber, and 14 is a heat recovery heat exchanger. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Patent applicant Mitsubishi Electric Corporation (2 others) TE TC=TA TG->1 size prisoner

Claims (1)

[Claims] A vapor compression refrigerator has a compressor that compresses refrigerant, a condenser that condenses the compressed refrigerant, an evaporator that evaporates the condensed refrigerant to generate cold heat, and a condenser that condenses the vapor generated in the generator. a thermally driven refrigerator having an evaporator for evaporating the liquid from the condenser, an absorber for absorbing the vapor from the evaporator into the liquid and sending the highly concentrated liquid to the generator; and the vapor compressor. A cooling system that extracts cold heat from the evaporator of the heat-driven refrigerator to the outside so that the condenser and the absorber of the heat-driven refrigerator can be cooled with the cold heat obtained by the evaporator of the heat-driven refrigerator. Composite refrigeration equipment equipped with