JPS6280452A - refrigeration cycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a refrigeration cycle, and particularly to a refrigeration cycle suitable for use in a quick-freezing refrigerator using a non-azeotropic mixed refrigerant.

[Background of the invention]

In quick-freezing refrigerators, the temperature is -40℃ during quick-freezing operation.
It is necessary to obtain an evaporation temperature of about -25°C during normal refrigeration operation. When trying to obtain these wide ranges of evaporation temperatures with a single composition refrigerant or an azeotropic mixture, if the optimal refrigerant is selected during normal refrigeration operation, the evaporation pressure will decrease as the evaporation temperature decreases during rapid refrigeration operation.
Due to lack of freezing capacity, it is difficult to quickly freeze the product.
This results in a disadvantage that the performance of the refrigeration cycle is reduced.

As a means to solve this drawback, a refrigeration cycle using a non-azeotropic mixed refrigerant is known. This type of refrigeration cycle uses two or more types of refrigerants, high boiling point and low boiling point, and during normal refrigeration operation, the high boiling point refrigerant is mainly operated, and at this time, the low boiling point refrigerant is separated from the refrigeration cycle and stored. Then, during quick freezing operation, this stored low boiling point refrigerant is released into the refrigeration cycle to become a non-azeotropic mixed refrigerant, and the evaporation temperature is 14
The system is designed to operate with high evaporation pressure even if the temperature drops to about []°C. Here, as shown in JP-A-59-197761 and JP-A-59-197762, a method is known in which the low boiling point refrigerant is separated and discharged by fractional distillation.

However, in order to reliably separate and discharge low-boiling point refrigerants using fractional distillation, the structure of the packing for fractional distillation is complicated, the size of the fractionator is also increased, and costs increase. was there.

[Purpose of the invention]

The present invention has been made in view of the above, and an object of the present invention is to provide a refrigeration cycle capable of separating and discharging a non-azeotropic mixed refrigerant with a simple configuration.

[Summary of the invention]

A feature of the present invention is that a container containing an adsorbent that adsorbs a low-boiling point refrigerant is connected to the refrigeration cycle, and during normal refrigeration operation, a non-azeotropic mixed refrigerant consisting of two or more types of high-boiling point and low-boiling point refrigerants is used. a first operating means for adsorbing and storing a low-boiling refrigerant in the adsorbent and operating with the high-boiling refrigerant; and during rapid freezing operation, reducing the pressure in the container and heating the adsorbent to release the low-boiling refrigerant. and a second operating means for operating with a mixed refrigerant.

[Embodiments of the invention]

The present invention will be described in detail below with reference to the embodiments shown in FIGS. 1, 2, 5, and 6, as well as FIGS. 3, 4, and 7.

FIG. 1 is a refrigeration cycle system diagram showing one embodiment of the refrigeration cycle of the present invention, and FIG. 2 is a circuit diagram showing a detailed embodiment of the operation control device in FIG. 1. In Figure 1,
1 is a compressor, 2 is a condenser, 6 is an expansion valve 54 is an evaporator, 5
is a freezer compartment housing the evaporator 4, which is thermally insulated from the outside world by a heat insulating material. 6 is an adsorbent, 7 is a container containing the adsorbent 6, 8 is a heater for heating the adsorbent 6, 8a
A thermostat detects the temperature of the adsorbent B and controls the temperature to a constant temperature by turning on and off the heater 8, and a mesh 9 prevents the adsorbent 6 from flowing into the refrigeration cycle. 10 is a three-way valve, one of which is connected to the container 7, and the container 7 is further connected to a refrigerant circuit via a two-way valve 11.

A non-azeotropic mixed refrigerant consisting of two components, a high boiling point and a low boiling point, is enclosed in the refrigeration cycle configured as described above. Now, -
As an example, R12 with a boiling point of 160°C as a high boiling point refrigerant,
Assume that R22 with a boiling point of 141° C. is used as a low boiling point refrigerant.

In addition, 16 is an operation control device that controls normal refrigeration operation and quick freezing operation, and 14 is a control device that detects the temperature in the freezer compartment 5 during normal refrigeration operation and turns the compressor 1 on and off. Freezer thermostat for controlling temperature constant, 1
Reference numeral 5 denotes a freezer compartment thermostat during quick freezing operation, which has a lower set operating temperature than the thermostat 14.

Next, the operation of the refrigeration cycle will be explained. During normal refrigeration operation, high-temperature, high-pressure refrigerant gas compressed by the compressor 1 is cooled by the condenser 2 to become a liquid, and then passed through the expansion valve 6 to reduce the pressure and temperature. Note that the opening degree of the expansion valve 3 depends on the operating conditions (evaporation temperature).
shall be adjusted accordingly. The cooled refrigerant enters the evaporator 4, cools the inside of the freezer compartment 5 by endothermic action, and returns to the compressor 1 through the three-way valve 10. At this time, the two-way valve 11 is opened and the low boiling point refrigerant R of the non-azeotropic mixed refrigerant is used.
22 is adsorbed and stored in the adsorbent 6 through the two-way valve 11, and the refrigerant circuit becomes a single refrigerant operation using the high boiling point refrigerant R12. Adsorption of low boiling point refrigerant R22.

The release action will be discussed later.

During quick freezing operation, the two-way valve 11 is closed, the three-way valve 10 is switched to communicate the compressor 1 and the container 7, and at the same time, the heater 8 is energized and the adsorbent 6 is heated. Then, the pressure inside the compressor 1 is reduced to about 10 wnHg, and the heater 8 is heated to a predetermined temperature! (100℃
), the low boiling point refrigerant R22 adsorbed and stored in the adsorbent 6 is desorbed and discharged into the refrigeration circuit through the three-way valve 10 and the compressor 1. This adsorbent 6
After performing a discharge operation of low boiling point refrigerant R22 for a predetermined period of time,
The three-way valve 10 is switched again, and at the same time the power to the heater 8 is stopped, the two-way valve 11 remains closed, and the compressor 1 → condenser 2 → expansion valve 6 → evaporator 4 → three-way valve 10 → compression A non-azeotropic mixed refrigerant consisting of two refrigerants, one with a low boiling point and one with a high boiling point, is circulated in the refrigerant circuit of the machine 1. Therefore, even if the evaporation temperature is lowered, the refrigerating capacity does not decrease, and rapid freezing becomes possible.

When performing normal freezing operation again from the above-mentioned rapid freezing operation state, by opening the two-way valve 11, the low boiling point refrigerant R22 of the non-azeotropic mixed refrigerant is adsorbed and stored in the adsorbent 6 again, and the refrigerant circuit Assume that the high boiling point refrigerant R12 single refrigerant operation is performed.

Next, the operation control device 13 will be explained in more detail. Second
In the figure, 13a is a changeover switch for selecting between normal operation and quick freezing operation, and 13b is a timer having a contact 13ba. It has become. 1
5a is a switch, 13d is a relay, and the switch 13c is switched by turning on and off the relay 13d.

Next, the operation control method will be explained. First, during normal refrigeration operation, the selector switch 13a is in the open state.
Since the relay 13d is off, the contact of the switch 13c conducts to the contact A side, and the temperature inside the freezer compartment 5 is detected by the freezer compartment thermostat 14, and the compressor 1 is turned on.
Perform normal refrigeration operation with off control. During quick freezing operation, the changeover switch 13a is closed, the two-way valve 11 is turned on (closed), and at the same time, the timer 13b is energized, and the contact 13 is turned on (closed).
ba is closed. Then, the three-way valve 10 and the heater 8 connected to the contact 13ba are energized, the three-way valve 10 is switched, and the heater 8 starts heating. Heating by the heater 8 is controlled by a thermostat 8a so that the temperature of the adsorbent B becomes a predetermined temperature (100° C.). In this way, when a certain period of time t (see FIG. 3, which is a time chart showing the control operation when switching from normal freezing operation to quick freezing operation in FIG. 1) has elapsed since the timer 13b is energized, the contacts 13b and is opened, the three-way valve 10 is turned off (normal state), power to the heater 8 is stopped, and rapid freezing operation is performed. At this time, the temperature in the freezer compartment 5 is controlled by the freezer thermostat 15 by energizing the relay 13d, which causes the switch 13c to conduct to the contact B side.

When shifting from the quick freezing operation to the normal freezing operation, the changeover switch 13a is opened to turn off the power to the timer 13b and the two-way valve 11, the relay 13d is no longer energized, and the switch 13c is a contact point. Conducted to the A side,
The compressor 1 is controlled on and off by the freezer compartment thermostat 14, and the mode is switched to normal refrigeration operation.

The control operations of the three-way valve 10, the two-way valve 11, and the heater 8 when switching from the normal freezing operation to the quick freezing operation are as shown in the time chart of FIG. 3. That is, during normal refrigeration operation, the changeover switch 13a is open, so
Everything is turned off. And switch j3c
To switch to quick freezing operation, press the selector switch 15a.
By closing, the timer 15b is energized to turn on the three-way valve 10 and the heater 8, and the three-way valve 11 is also energized and turned on. However, after a certain period of time has elapsed, the contact point 13ba is opened, so the three-way valve 1o and the heater 8 are turned off, resulting in rapid freezing operation. Note that during the refrigerant switching operation, the heater 8 is controlled on and off by the thermostat 8a so that the adsorbent 6 reaches a predetermined temperature.

Next, the adsorption and release effects of the fluorocarbon refrigerant will be explained.

The adsorbent 6 used in the present invention has selective adsorption characteristics for fluorocarbon refrigerants, and uses zeolite, for example.

Figure 4 is a diagram showing an example of the adsorption characteristics of zeolite in the case of R22. During normal refrigeration operation, when the evaporation temperature is -25°C with R12 single refrigerant operation, the evaporation pressure is 23 kg/c.
rl G (inside 930 mmHg), the amount of R22 adsorbed on zeolite is as follows, assuming the outside temperature is 25°C.
At point X, it is approximately 28% by weight. At this time, the refrigerant circuit is operated with a single refrigerant. Next, when performing a quick freezing operation, the zeolite is heated to 100°C by the heater 8,
Furthermore, the pressure decreases to about 10 mmHg due to suction by the compressor 1, so the amount of R22 adsorbed on the zeolite at this time is about 8% by weight as at point Y, and the difference is 17% by weight. is desorbed and the refrigeration cycle becomes operated with mixed refrigerant. When returning from quick freezing operation to normal freezing operation, the power supply to the heater 8 is stopped and the temperature of the adsorbent zeolite is cooled by outside air and becomes 25°C again, so R22 is adsorbed until it reaches the original 28 weight ratio. , it is possible to return to R12 single refrigerant operation. Although the heater 8 is used here as a heating means for the adsorbent, the heat dissipation of the refrigeration cycle may also be used.

According to the embodiment of the present invention described above, the low boiling point refrigerant is adsorbed by the adsorbent B which has selective refrigerant adsorption characteristics, and the adsorbed refrigerant is desorbed by depressurization and heating at the time of release, so the structure is simple. It is possible to switch between high boiling point single refrigerant operation and non-azeotropic mixed refrigerant operation, and it is possible to provide a refrigeration cycle using non-azeotropic mixed refrigerants with high practical effects.

FIG. 5 is a refrigeration cycle system diagram corresponding to FIG. 1 showing another embodiment of the present invention, and FIG. 6 is a circuit diagram corresponding to FIG. 2 showing an example of details of the operation control device in FIG. Figure 7 is a time chart showing the control operation when switching from normal freezing operation to rapid freezing operation in Figure 5.
6, the same parts as in FIGS. 1 and 2 are indicated by the same reference numerals, and their explanation will be omitted here. Figure 5 shows a system in which the inside of the container 7 is evacuated by the suction action of an ejector installed in the refrigeration circuit, without relying on the compressor 1, and the switch from normal refrigeration operation to quick refrigeration operation can be smoothly performed. That's how it is. In FIG. 5, 12 is an ejector, and the ejector 12 and the container 7 are connected via a two-way valve 11'. One of the paths is configured to bypass the ejector 12. With this configuration, during normal refrigeration operation, the three-way valve 11'
is opened and the refrigerant is circulated through the refrigerant circuit of compressor 1 → condenser 2 → expansion valve 3 → evaporator 4 → three-way valve 10' → compressor 1 to perform single refrigerant operation. During quick freezing operation, two-way refrigerant operation is performed. Valve 11'
is kept open, the three-way valve 10' is switched, and the refrigerant gas leaving the evaporator 4 is passed through the ejector 12 and returned to the compressor 1, and the suction action of the ejector 12 causes the container 7 to be vacuumed (1o).

The low boiling point refrigerant R22, which had been adsorbed on the adsorbent B, was
As a result, the mixed refrigerant gradually circulates in the refrigerant cycle. The valve 11' is closed, the power supply to the heater 8 is stopped, and the three-way valve 10' is switched to bypass again to perform non-azeotropic mixed refrigerant operation.

Next, the operation control device 13' shown in FIG. 5 will be explained using FIG. 6. In FIG. 6, the difference from FIG. 2 is that the timer 13b has two contacts 13ba + 13b.
b*, the operation of contacts 13ba and 13bb is controlled by contact 1 for a certain period of time (1) after the timer 13b is energized.
3ha is closed, and contact 13bb is opened. After a certain period of time t has elapsed, the contact 13a is opened and the contact 13bb is closed. Therefore, when the changeover switch 13a is closed and the normal freezing operation is switched to the quick freezing operation, the timer 13b is energized, the contact 13b& is closed, and the three-way valve 10' and the heater 8 connected to the contact 13ba are energized. , the three-way valve 10' is switched, and the heater 8 starts heating. In this way, when a certain period of time t (see FIG. 7) has elapsed since the timer 13b was energized, the contact 13ba is opened, the three-way valve 10' is turned off, the heating of the heater 8 is stopped, and at the same time, the contact 13bb is closed. Then, the two-way valve 11' is turned on (closed) and rapid freezing operation begins.

Note that the non-azeotropic mixed refrigerant is not limited to the high boiling point refrigerant R12 and the low boiling point refrigerant R22, and the same effect can be obtained by mixing other high boiling point refrigerants and low boiling point refrigerants.

In addition, although the above-mentioned embodiment describes a quick-freezing refrigerator, the present invention is not limited to this, and the present invention is not limited to this. Heat pumps, etc.) can be applied and the same effect can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to separate and discharge a non-azeotropic mixed refrigerant with a simple configuration, and it is possible to switch between high boiling point single refrigerant operation and non-azeotropic mixed refrigerant operation, This has the effect of providing a refrigeration cycle using a non-azeotropic mixed refrigerant that is highly practical.

[Brief explanation of drawings]

FIG. 1 is a refrigeration cycle system diagram showing one embodiment of the refrigeration cycle of the present invention, FIG. 2 is a circuit diagram showing an embodiment of the operation control device in detail in FIG. 1, and FIG. A time chart showing the control operation when switching from normal freezing operation to quick freezing operation, Fig. 4 is a diagram showing an example of the adsorption characteristics of zeolite in the case of low boiling point refrigerant R22, and Fig. 5 is a diagram showing an example of the adsorption characteristics of zeolite in the case of low boiling point refrigerant R22. 6 is a circuit diagram corresponding to FIG. 2 showing an example of details of the operation control device in FIG. 5, and FIG. 7 is a circuit diagram corresponding to FIG. 3 is a time chart corresponding to FIG. 3 in the figure. 1... Compressor 2... Condenser 3... Expansion valve 4... Evaporator 5... Freezer compartment 6... ... Adsorbent 7 ... Container 8 ... Heater 8a ... Thermostat 9 ... Mesh 10.10 ... Three-way valve 11.11 ... ... Two-way valve 12 ... Ejector 13.13 ... Operation control device 13a ...
... Selector switch 13b ... Timer 13ba, 13bb -- Contact 13c ... Switch 13d ... Relay 14.15 ... Freezer compartment thermostat.

Claims (1)

[Claims] 1. In a refrigeration cycle equipped with at least a compressor, a condenser, an expansion valve, and an evaporator and filled with a non-azeotropic mixed refrigerant consisting of two or more types of high-boiling refrigerants, the low-boiling refrigerant is adsorbed in the refrigeration cycle. Connect the container containing the adsorbent,
a first operating means that adsorbs and stores the low boiling point refrigerant in the adsorbent and operates with the high boiling point refrigerant during normal refrigeration operation; A refrigerant cycle characterized by comprising: a second operating means for discharging a low boiling point refrigerant and operating with a mixed refrigerant.