JPS61186765A - Refrigeration cycle device - 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 Industrial Application] The present invention relates to a refrigeration cycle device that can obtain two different cooling temperatures with one compressor, and is suitable for use in, for example, a vehicle cooling and refrigerating device. It is something.

[Conventional technology]

In Japanese Patent Application No. 58-155899, the present applicant previously proposed a cooling circuit that uses a common compressor and condenser, and includes a cooling pressure reduction device and a cooling evaporator downstream of the condenser. and a refrigeration circuit including a refrigeration pressure reducing device and a refrigeration evaporator are provided in parallel, and the compressor is provided with a cooling inlet and a refrigeration inlet independently, and a cooling inlet and a refrigeration inlet are provided downstream of the cooling evaporator. According to this refrigeration cycle device, the refrigeration cycle device proposes a refrigeration cycle device in which the downstream side of the refrigeration evaporator is connected to the cooling inlet, and the downstream side of the refrigeration evaporator is connected to the refrigeration inlet. By drawing the refrigerant that has passed through the circuit into the compressor independently, the evaporation pressure in each evaporator can be set to a separate value, for example 2 in the case of a cooling evaporator.
．． 5 k+r/cal G (in the case of refrigerant R-12,
The evaporation temperature is 4℃), and the evaporator for refrigeration is 0.5 kg/
c4 G (In the case of refrigerant R-12, the evaporation temperature is -21'
C), it is possible to obtain a cooling temperature suitable for cooling and refrigeration in each evaporator.

In addition, in the device of the above-mentioned prior application, by providing a communication mechanism in the compressor that allows the refrigerant to be mixed with the cooling refrigerant (high-pressure refrigerant) after sucking the refrigerant and before compressing it, the cooling side is substantially reduced. Efforts are being made to minimize the decline in cooling capacity by increasing the flow rate of refrigerant.

[Problem that the invention seeks to solve]

However, when the cooling load or refrigeration load is large, even with the above configuration, capacity may still be insufficient.

Therefore, in view of the above points, it is an object of the present invention to provide a refrigeration cycle device that can improve performance with an extremely simple configuration without increasing the size of the compressor, condenser, etc.

[Means for solving problems]

In order to achieve the above object, the present invention provides at least a first suction port and a second suction port independently, compresses the refrigerant sucked in from the two eye entrances, and discharges it from one discharge port. (b) a condenser configured to condense the gas refrigerant discharged from the compressor into liquid refrigerant; (di) a first pressure reducing device and a first evaporator provided between the refrigerant outlet side of the receiver and the first suction port; a second pressure reducing device and a second evaporator provided between the first evaporator and the second inlet; The compressor is configured such that the evaporation pressure decreases in the order of the second evaporator, A communication mechanism is provided for mixing the high-pressure refrigerant (hl).
, a high-pressure side refrigerant pipe leading to the inlet of the second pressure reducing device, a first suction pipe leading from the refrigerant outlet side of the first evaporator to the first suction port, and a refrigerant of the second evaporator. A technical measure is adopted in which a heat exchanger is provided for exchanging heat with a second suction pipe extending from the outlet side to the second suction port.

In a specific embodiment of the present invention, the first evaporator constitutes a cooling evaporator that cools air for cooling the vehicle interior,
The second evaporator constitutes a refrigeration evaporator that cools the interior of the vehicle refrigerator.

[For production]

According to the above-mentioned technical means, the high-temperature liquid refrigerant in the high-pressure side refrigerant pipe is transferred to the first pipe which is at a low temperature. It can be cooled by heat exchange between the second suction pipe and the first suction pipe.
The liquid refrigerant flowing into the second pressure reducing device can be given supercool (supercooling degree), and the cooling and refrigerating capacity can be improved.

〔Example〕

Hereinafter, the present invention will be explained in detail based on specific examples. FIG. 1 is a refrigeration cycle diagram showing a specific embodiment in which the present invention is applied to an automobile refrigeration cycle device that serves both the function of cooling a vehicle interior and the function of refrigerating articles. Compressor 2
1 is coupled via an electromagnetic clutch 20 to a drive shaft of an automobile engine (not shown). In this example, the compressor 21 is a swash plate type compressor with 10 cylinders, of which 9 cylinders are configured as a main compression section 21a for cooling, and the remaining 1 cylinder is configured as a sub-compression section 21b for refrigeration. Here, each compressor section 21a, 21b of the compressor 21 has a cooling suction port 2.
1c and a refrigerating inlet 2d are provided independently. The cooling main compression section 21a and the refrigeration sub-compression section 21b are communicated with each other by a communication passage 21s provided in the compressor, and the refrigerants (R12) having different pressures are sucked from the respective suction ports 21C and 21d. Before being compressed in each compression section 21a, 21b, the communication passage 21g communicates with the refrigerant, and after the pressure is increased to the pressure of the cooling refrigerant, it is compressed in each compression section and discharged from a common discharge port 21f. It has become.

A discharge port 21f of the compressor 21 is connected to a condenser 22, and a discharge side of the condenser 22 is connected to a receiver 23. On the discharge side of the receiver 23, a cooling air pressure reducing device is disposed via a high-pressure refrigerant pipe 51, for example, on the upstream side of the air conditioner 5, a cooling air blowing fan 50 is disposed. The refrigerant outlet side of the evaporator 25 is connected to the cooling suction port 21C of the compressor 21 by a cooling suction pipe 52. 24a is a heating cylinder of the expansion valve 24. □ On the other hand, a refrigeration circuit is provided in parallel with the cooling expansion valve 24 and the evaporator 25, and this refrigeration circuit includes a constant pressure expansion valve 27, which is a specific example of a refrigeration pressure reducing device, and a constant pressure expansion valve 27 connected thereto. A refrigerating evaporator 28 is provided, and a check valve 29 is provided that allows refrigerant gas to pass only in one direction toward the compressor suction side. The discharge side of this check valve 29 is connected to a refrigeration suction pipe 53.
It is connected to the refrigeration suction port 21d of the compressor 21. The constant pressure expansion valve 27 has a downstream pressure, that is, a pressure inside the refrigeration evaporator 28, at a set pressure of, for example, 0.5 kg.
/dG or less, the valve opens. Reference numeral 49 denotes a communication path that directly connects the cooling suction pipe 52 and the refrigeration suction pipe 53. A solenoid valve 48 is installed in this communication path 49, and when the solenoid valve 48 is opened, both the suction pipes 52.
53 are in communication.

Further, the refrigerating evaporator 28 is housed in a regenerator 30 filled with a regenerator material 31. As the cold storage material 31, for example, potassium chloride 19.7 having a freezing temperature of -11°C is used.
% eutectic solution is used. 54 is the above-mentioned high pressure side refrigerant pipe 5
1 and the cooling suction pipe 52 and the refrigeration suction pipe 53, and its detailed structure is shown in the second section.
As shown in FIG. 3, each of the pipes 51, 52.
53 each have a flat portion 51a for increasing the heat transfer area.
, 52a, 53a, and these flat parts 51a, 52a
, 53a, the pipes 51, 52, 53 are arranged in close contact with each other, and then their outer peripheries are covered with a heat insulating cover 55 made of a heat insulating material such as resin or rubber. This heat exchanger 54 is usually installed in the engine room of a car for reasons of space, and therefore the heat insulating cover 55 is provided, but it may be possible to install it inside the car due to space considerations. For example, the heat insulating cover 55 can be eliminated.

Next, the electric circuit of the refrigeration cycle device configured as described above will be described. Reference numeral 1 denotes an on-vehicle battery, and a cooling control circuit 3 is connected to the battery 1 via a cooling switch 2.

4 is a refrigerator switch, which is connected to the battery 1 via the cooling switch 2;
A refrigerator control circuit 5 is connected to. 6 is a temperature sensor attached to the air blowing side of the cooling evaporator 25;
It consists of a thermistor and is connected to the cooling control circuit 3. In order to prevent the cooling evaporator 25 from freezing, this temperature sensor 6 increases its resistance value when the temperature of the blown air falls below a set temperature.The cooling control circuit 3 determines this change in resistance value, and The compressor 21 is turned off and the compressor 21 is stopped.

Reference numeral 7 denotes a temperature sensor installed to sense the outer surface temperature of the regenerator 30 in which the refrigerating compression section 28 is housed, and is made of a thermistor and connected to the refrigerator control circuit 5.

The solenoid valve 48 is controlled to open and close by an output signal from the refrigerator control circuit 5.
In this example, a structure is used that closes when energized and opens when energization is interrupted. Further, the refrigerator control circuit 5 is configured to turn on a display device 8 such as a lamp or an LED based on the temperature detected by the temperature sensor 7.

Refrigerating regenerator 30 housing the aforementioned refrigerating evaporator 28
, the constant pressure expansion valve 27, and the check valve 29 are installed in a refrigerator (not shown). will be installed.

Next, the operation of this embodiment in the above configuration will be explained. Now, when the cooling switch 2 is turned on while the automobile engine is operating, current flows through the cooling control circuit 3 to the excitation coil of the electromagnetic clutch 20, and the electromagnetic clutch 20 is connected. The driving force of the engine is the compressor 21
The compressor 21 rotates and compresses the refrigerant gas.

In the above state, the opening and closing of the refrigerator switch 4 and the freezing and unfrozen state of the cold storage material 31 will be sequentially explained.

First, a case will be described in which the refrigerator switch 4 is closed and the cold storage material 31 is not frozen.

Here, it has been found through experiments that the degree of freezing of the cold storage material 31 is sufficiently frozen if the surface temperature of the cold storage material 31 is 112 degrees Celsius or less. 5
The set temperature is determined as 2, and the set temperature and the temperature detected by the temperature sensor 7 are compared and determined by a comparator in the control circuit 5 to determine whether or not the cold storage material 31 is frozen. When the cold storage material 31 is not frozen, the output of the comparator energizes the solenoid valve 48 to keep the solenoid valve 48 in a normally closed state.

The refrigerant gas discharged from the compressor 21 is cooled and condensed by the condenser 22, and the liquefied refrigerant is stored in the receiver 23. This liquefied refrigerant is depressurized via the high-pressure refrigerant pipe 51 by the action of the temperature-operated expansion valve 24 for cooling and the constant-pressure expansion valve 27 for refrigeration, becoming a low-temperature, low-pressure gas-liquid two-phase refrigerant, and then the evaporator 25. At 28, it evaporates and takes away the heat from the surroundings. The refrigerant that has passed through the cooling evaporator 25 passes through the cooling suction pipe 52 and is sucked into the compression a21 from the cooling suction port 21C. On the other hand, the refrigerant that has passed through the refrigeration evaporator 28 passes through the check valve 29, the refrigeration suction pipe 53, and is sucked into the compressor 21 from the refrigeration suction port 21d. Here, as described above, at the end of the suction stroke, the refrigeration compression section 21b of the compressor 21 communicates with the cooling compression section 21a through the communication passage 21e, and the pressure of the refrigerant that has passed through the cooling evaporator 25 (for example, 2. 5 kg/cdG), all cylinders of the compressor 21 compress refrigerant whose pressure is 2.5 kg/c1dG. The refrigerant supplied to the refrigeration circuit is
Constant pressure expansion valve 27 (set pressure Q, 5 kg/cal
Due to the action of G), an evaporation pressure of 0.5 kg/cdG and an evaporation temperature of -21° C. are established in the refrigerating evaporator 28, and the regenerator 31 in the regenerator 30 is gradually frozen.

FIG. 4 is a Mollier diagram of the refrigeration cycle according to the present invention, where PL indicates the evaporation pressure in the cooling evaporator 25 and PL indicates the evaporation pressure in the refrigeration evaporator 28.

PH indicates high pressure side pressure (condensation pressure).

Next, a case will be described in which the refrigerator switch 4 is closed and the refrigerating regenerator 31 is sufficiently frozen, that is, the outer surface temperature of the refrigerating regenerator 31 is 112° C. or less. At this time, the comparator in the control circuit 5 determines the detection signal of the temperature sensor 7 and cuts off the power to the solenoid valve 48, so that the solenoid valve 48 remains open at all times. When the solenoid valve 48 is opened, the cooling refrigerant (pressure is 2°5 kg/
cIAC) flows in, the constant pressure expansion valve 27 for refrigeration closes, and no refrigerant flows into the refrigeration circuit. In addition, the control circuit 5
stops the energization to the solenoid valve 48 and turns on the refrigeration display device 8 to indicate that the refrigeration cold storage agent 31 has been frozen.

Note that since a check valve 29 is disposed downstream of the refrigeration evaporator 28, there is no possibility that the refrigerant on the cooling side will pass through the pipe 53 and suddenly increase the pressure inside the refrigeration evaporator 28. do not have.

In the automobile air conditioner, the compressor 21 is controlled intermittently by various signals as is well known, but when the compressor 21 is stopped by this intermittent control, the evaporation pressure in the cooling evaporator 25 is Although the pressure gradually rises, the pressure inside the refrigerating evaporator 28 does not rise due to the action of the check valve 29.

As described above, by operating the refrigeration cycle and freezing the cold storage agent 31, even when the refrigeration cycle is stopped, such as when parking, the temperature inside the refrigerator is kept low by the latent heat of fusion of the cold storage agent 31, and the contents are kept low. Can be kept cold at a low temperature.

Next, the function of the heat exchanger 54 in the refrigeration cycle will be described in detail. First, considering the case where the heat exchanger 54 is not installed, in this case, the supercool (supercooling degree) of the liquid refrigerant at the outlet of the receiver 23 is almost zero, so the solid line 90 in the Mollier diagram in FIG. The cycle is shown in .

For this reason, as shown by the solid line 90, gas that does not contribute to the cooling and refrigerating effect is inevitably generated during the depressurization process. According to experiments conducted by the inventor, the amount of gas generated is high pressure 15k in a typical vehicle cooling cycle without a refrigerator.
g/7G and low pressure 2kg/Cl1G, about 40% occurs. Since the cycle of the present invention uses the constant pressure expansion valve 27 on the refrigerator side, the refrigerator side circuit always operates under the same evaporation pressure. Therefore, regardless of the size of the load on the refrigerator, only a constant flow of refrigerant always flows through the refrigerating evaporator 28, and as a result, when the refrigerating load is large, problems such as insufficient cooling inside the refrigerator occur.
Conversely, when the refrigeration load is small, problems such as liquid refrigerant returning to the compressor 21 may occur. Therefore, the present invention provides a heat exchanger 54 that exchanges heat between the high-pressure side refrigerant pipe 51 connected to the outlet side of the receiver 23 and the low-temperature cooling and refrigeration suction pipes 52 and 53, so that the high-temperature liquid at the receiver outlet is The refrigerant was cooled to provide supercool (SC in Figure 4). Here, the temperature of each pipe varies depending on the load, but it is approximately the following value. The high pressure side refrigerant pipe 51 is approximately 60°C, and the cooling suction pipe 52 is approximately 7°
The temperature of the C1 refrigeration suction pipe 53 is about -10°C. As a result, the high-temperature liquid refrigerant in the refrigerant pipe 51 is cooled, and the low-temperature suction pipes 52 and 53 are heated. Refrigerant piping 5
1, the liquid refrigerant can have supercool (SC), and as a result, the enthalpy i increases by 61 minutes as shown by the broken line 91 in Fig. 4, and the cooling and refrigeration capacity can be increased. .

In addition, on the refrigerator side, the generation of gas refrigerant is promoted by exchanging heat with the high temperature refrigerant at the outlet side of the evaporator 28, so it is possible to suppress the return of liquid refrigerant to the compressor 21 as much as possible during low load. , it can also be used to improve the safety of the compressor 21.

5 and 6 show other embodiments of the heat exchanger 54 according to the present invention, in which each pipe 51, 52, 53 is passed inside a heat insulating container 56 made of a heat insulating material such as resin. A secondary medium 57 is sealed inside the container 56, and heat exchange between the pipes is performed via the secondary medium 57.

Although any medium can be selected as the secondary medium 57, water is generally sufficient. However, considering the problem of corrosion of piping and containers, it is necessary to add anticorrosive agents and select a non-corrosive secondary medium.

In the embodiment shown in FIG. 1, the temperature sensing tube 24a of the expansion valve 24
The suction pipe 52 located immediately after the outlet of the cooling evaporator 25
The expansion valve 24 is provided at
Since the opening degree of the evaporator 25 is controlled, superheated refrigerant inevitably exists in the evaporator 25, which is one of the factors that reduce the cooling capacity.

Therefore, in the embodiment shown in FIG. 7, the temperature-sensitive cylinder 24a of the expansion valve 24 is provided on the suction pipe 52 after passing through the heat exchanger 54, so that the refrigerant does not become superheated in the evaporator 25. , which aims to improve cooling capacity.

The present invention is not limited to the illustrated embodiments described above, but can be implemented in a wide variety of ways, and representative modifications will be listed below.

(11 When using a swash plate type multi-cylinder compressor 21, the number of refrigerating compression sections 21b is not limited to one cylinder, but it is of course possible to increase the number of cylinders as appropriate depending on the capacity required for the refrigerator. .

(2) In addition to the swash plate type multi-cylinder compressor 21 described above, a vane type compressor can also be used.

In that case, if the refrigeration suction port 21d and the cooling suction port 21C are sequentially opened in order of decreasing suction pressure along the rotational direction of the rotor, the respective compression sections 21b and 21a will all have the highest suction pressure of 2.5 kg/ It becomes possible to start compression of the refrigerant in a state where cjG is reached.

(3) As the pressure reducing device on the refrigeration side, in addition to the constant pressure expansion valve 27, a normal temperature-operated expansion valve, a fixed throttle, or the like can be used.

(4) The cooling control circuit 3 and the refrigerator control circuit 5 may be integrated, or both circuits 3 and 5 may be configured using a microcomputer that performs digital arithmetic processing.

(5) The set pressure of the constant pressure expansion valve 27 can be freely changed depending on the desired cooling temperature in the refrigerator, the freezing temperature of the cold storage agent 31, and the like.

(6) The refrigerating evaporator 28 is not limited to one that cools the cold storage agent 31, but can also be applied to one that directly cools the air inside the refrigerator, and in that case, it does not matter whether or not an internal fan is used.

(7) In the refrigeration cycle shown in Fig. 1, only one refrigeration circuit is connected in parallel to the cooling circuit, but it goes without saying that two or more refrigeration circuits may be connected in parallel.
In that case, it is preferable to pass all suction piping through a heat exchanger.

(8) Furthermore, in the above-mentioned embodiments, the case where cooling and refrigeration functions are obtained was explained, but the present invention can also be applied to applications that do not require cooling functions; for example, in a single refrigerator, two The present invention can be effectively applied to cases where different cooling temperatures (evaporation pressures) are set as described above.

〔Effect of the invention〕

As described above, according to the present invention, 1. Noting that the second suction pipe 52.53 is at a low temperature, by exchanging heat between this re-suction pipe 52.53 and the high pressure side refrigerant pipe 51, the temperature inside the high pressure side refrigerant pipe 51 is reduced. Since the liquid refrigerant can be made supercool, it has the excellent effect of increasing capacity with an extremely simple configuration without increasing the size of the compressor, condenser, etc.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle diagram of one embodiment of the present invention, including an electrical circuit. 2 is a longitudinal sectional view of the heat exchanger 54 of FIG. 1, FIG. 3 is a front view of the heat exchanger 54, FIG. 4 is a Mollier diagram of the refrigeration cycle of the present invention, and FIG. 5 is a heat exchanger of the present invention. 6 is a longitudinal sectional view of the heat exchanger 54 shown in FIG. 5, and FIG. 7 is a refrigeration cycle diagram showing another embodiment of the present invention. 21...Compressor, 21f...Discharge port, 21c...
Cooling inlet (first inlet), 21d... Refrigeration inlet (second inlet), 21e... Communication mechanism, 22.
... Condenser, 23... Receiver, 24... Cooling pressure reducing device (first pressure reducing device), 25... Cooling evaporator (
27... Refrigeration pressure reducing device (second pressure reducing device), 28... Refrigeration evaporator (second evaporator),
51... High pressure side refrigerant pipe, 52... Cooling suction pipe (first suction pipe), 53... Refrigeration suction pipe (second suction pipe), 54... Heat exchanger.

Claims (1)

[Scope of Claims] (a) At least a first suction port and a second suction port are independently provided, and the refrigerant sucked from each of the suction ports is compressed and discharged from one discharge port. (b) a condenser that condenses the gas refrigerant discharged from the compressor into liquid refrigerant; and (c) a condenser provided on the refrigerant outlet side of the condenser to store liquid refrigerant and convert the liquid refrigerant into (d) a first pressure reducing device and a first evaporator provided between the refrigerant outlet side of the receiver and the first suction port; (e) a refrigerant outlet side of the receiver; and a second pressure reducing device and a second evaporator, the first pressure reducing device and the second pressure reducing device are provided between the first pressure reducing device and the second inlet. (g) The compressor is configured such that the evaporation pressure decreases in the order of the evaporator and the second evaporator; (h) a high-pressure side refrigerant that flows from the refrigerant outlet side of the receiver to the inlets of the first and second pressure reducing devices; a first suction pipe leading from the refrigerant outlet side of the first evaporator to the first suction port, and a second suction pipe leading from the refrigerant outlet side of the second evaporator to the second suction port. A refrigeration cycle device characterized by having a heat exchanger that exchanges heat with a suction pipe.