JP3321192B2 - Refrigeration circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

RELATED APPLICATION DISPLAY This application is based on commonly assigned US patent application Ser. No. 612,290.
No. (filed Nov. 9, 1990).

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration apparatus, and more particularly to a heat transfer structure suitable for a refrigeration apparatus including a plurality of evaporators and one compressor unit.

[0002]

2. Description of the Related Art In a typical refrigeration system, a refrigerant continuously circulates in a closed circuit. Here, the term "circuit" refers to a physical device, and the term "cycle" refers to the operation of a circuit, for example, a refrigerant cycle in a refrigeration circuit. Also, the term "refrigerant" means a refrigerant in a liquid, vapor and / or gaseous state. The refrigerant undergoes temperature / pressure changes depending on the components of the closed circuit. Energy transfer occurs as a result of the change in temperature / pressure of the refrigerant. Typical components of the refrigeration system include, for example, a compressor, a condenser, an evaporator, a control valve, and a connection pipe. For details of the well-known refrigeration apparatus, see “Mechanical Engineering Standard Handbook” by Baumeister et al. (Bau
meister et al. , Standard H
andbook for Mechanical En
giners, McGraw Hill Book
Company, Eightth Edition,
1979), pages 19-6 et seq.

[0003] Energy efficiency is one of the important factors in realizing a refrigeration system. In particular, an ideal refrigeration system produces an ideal refrigeration effect. In reality, the actual refrigeration effect provided by an actual refrigeration system is lower than the ideal refrigeration effect. And the actual refrigeration effect obtained differs from device to device.

[0004] Energy efficiency improvements are typically achieved by using more expensive and more efficient refrigeration equipment components, adding extra insulation adjacent to the area to be frozen, Alternatively, other expensive accessories are provided. Therefore, increasing the energy efficiency of a refrigeration system usually increases the cost of the system. Of course, it is desirable to increase the efficiency of the refrigeration system and minimize the cost of the system.

[0005] Some devices that utilize refrigeration equipment require that more than one area be frozen, and that at least one area be more strongly frozen than another. A home refrigerator including a freezer compartment and a fresh food compartment is a typical example of such an apparatus. Preferably, the freezer compartment is maintained between -10F and + 15F and the fresh food compartment is maintained between + 33F and + 47F.

[0006] To meet such temperature requirements, a typical refrigeration system combines a compressor with an evaporator located in a domestic refrigerator. Here, the terms “bond” and “link” are used as interchangeable terms. When joining or connecting two components, this means that these two components are linked, directly or indirectly, in some way to a refrigerant flow relationship. One or more other components may be interposed between the connected or connected components. For example, if other components such as pressure sensors or expansion devices are coupled or coupled to the compressor-evaporator link, the compressor and evaporator are still coupled or coupled.

To further illustrate a typical home refrigerator refrigerating system, the evaporator is maintained at about -10.degree. F. (in practice, a range of about -30.degree. F. to 0.degree. F. is typically used). And blow air to the coil of the evaporator. The flow of air cooled by the evaporator is controlled by, for example, a barrier. A first portion of the air cooled by the evaporator is sent to the freezer compartment and a second portion is sent to the fresh food compartment. To cool the fresh food compartment, instead of utilizing evaporator cooling air from an evaporator operating at -10 ° F, for example, +25
Evaporators operating at 0 ° F (or in the range of about + 15 ° F to + 32 ° F) can be used. Therefore,
Typical refrigeration systems used in home refrigerators are suitable for freezer compartments, but achieve a refrigeration effect by operating the evaporator at a temperature lower than that required for fresh food compartments.

As is well known, an evaporator is provided in a refrigerator.
The energy required to maintain 10 ° F. is greater than the energy required to maintain the evaporator at + 25 ° F. Thus, typical home refrigerators use more energy than necessary to cool the fresh food compartment. Using more energy than necessary reduces energy efficiency.

The above example of a home refrigerator has been described for illustrative purposes only. Many systems other than home refrigerators use refrigeration systems that include an evaporator that operates at a lower temperature than the evaporator actually needs to operate.

[0010] Energy saving refrigeration systems are described in commonly assigned US Patent Nos. 4,910,972 and 4,918,942. The devices of these patents use at least two evaporators and multiple compressors or a single compressor with multiple stages. For example, in a dual evaporator circuit for a home refrigerator, the first evaporator operates at + 25 ° F and the second evaporator operates at -10 ° F. The air cooled by the first evaporator is used in the fresh food compartment, and the air cooled by the second evaporator is used in the freezer compartment. Using a double evaporator refrigeration system in a home refrigerator increases energy efficiency. Rather than operating the evaporator for the fresh food compartment at -10 ° F.,
Place the evaporator at the temperature required for the fresh food compartment (eg + 25 °)
Save energy by operating in F).
Another feature of the device of the above patent also promotes increased energy efficiency.

In the refrigerating apparatus described in US Pat. Nos. 4,910,972 and 4,918,942, one compressor having a plurality of compressors or a plurality of stages is used to drive a plurality of evaporators. Use a compressor. Using multiple compressors or a single compressor with multiple stages makes the cost of the refrigeration system at least initially higher than the cost of a refrigeration system using one evaporator and one single-stage compressor.

Applicant's US Pat. No. 5,228,308
The refrigeration system described in U.S. Patent Application No. 612,290 achieves improved energy efficiency by using multiple evaporators and uses multiple compressors or a single compressor having multiple stages. Minimize, if not eliminate, the cost associated with use. Describing the patent in more detail, according to a first embodiment of the present invention, a refrigeration apparatus includes a refrigerant flow control unit and a compressor unit. In a specific embodiment, the compressor unit is a single stage compressor. The refrigerant flow control unit is connected to the plurality of input pipes. Each pipe, in a specific embodiment, contains a refrigerant therein, and each refrigerant is at a respective pressure. For example, a first input to the control unit is a high pressure refrigerant and a second input to the control unit is a low pressure refrigerant. The outlet of the refrigerant flow control unit is connected to the inlet of the compressor unit.

In operation, each refrigerant is supplied as an input to a control unit as described above, and the control unit supplies its respective refrigerant flow alternately to the compressor unit. Refrigerant flow timing, i.e., the length of time each input refrigerant is allowed to flow to the compressor unit, is based on a linear time base or based on measurable physical attributes such as the pressure, temperature, density and / or density of each refrigerant. Alternatively, it is determined according to the flow rate.

In one circuit embodiment, for example, if the thermal load on the freezer evaporator is significantly lower than the design load,
The liquid refrigerant that has not evaporated is discharged from the freezer evaporator. Thus, under these conditions, the potential cooling capacity of the freezer evaporator is reduced, but the work required by the compressor unit is not substantially affected.

In order to recover some of the lost cooling capacity,
The piping connected to the outlet of the freezer evaporator, i.e. the suction line, is arranged in heat transfer relationship with the piping connected to the outlet of the condenser. As a result of the heat transfer arrangement, the refrigerant liquid exiting the condenser is further subcooled, thereby reducing the enthalpy of the refrigerant before expansion in the fresh food compartment evaporator. This heat transfer effectively shifts and recovers the specific cooling capacity, [(mass flow) x (enthalpy change)], from the freezer evaporator to the fresh food room evaporator.

However, as is well known, the mechanical energy required to provide a mass flow to a freezer evaporator is greater than the mechanical energy required to provide a mass flow to a fresh food room evaporator. That is, operating the evaporator at lower temperatures requires more mechanical energy. The cooling capacity can be regained by the above-mentioned heat transfer, but if at least a part of the regained cooling capacity can be given to the freezer evaporator, the mechanical energy required to operate the freezer evaporator is reduced. Is the most desirable because it can be.

[0017]

It is an object of the present invention to improve the energy efficiency of a refrigeration system in which a single compressor unit is directly or indirectly connected to a plurality of evaporators.

It is another object of the present invention to regain the cooling capacity of an evaporator operating at a low temperature in a refrigeration system.

Another object of the present invention is to reduce the mechanical energy required to operate a refrigeration system having a plurality of evaporators.

[0020]

SUMMARY OF THE INVENTION The present invention is believed to be most suitable for use in refrigeration systems having two or more evaporators, for example, a refrigeration system including a fresh food room evaporator and a freezer evaporator. Specifically, in an apparatus according to an embodiment of the present invention, a capillary connected to the inlet of the freezer evaporator is connected to a suction line of the freezer evaporator, for example, between the outlet of the freezer evaporator and the inlet of the compressor unit. Arrange in heat transfer relationship with connected piping.

The refrigeration apparatus according to one embodiment of the present invention includes a condenser having a plurality of evaporators and connected to an outlet of a compressor unit. In this embodiment, the compressor unit is a single stage compressor. A first evaporator is coupled via a first expansion device;
Receives refrigerant discharged from the condenser. The outlet of the first evaporator is coupled to a phase separator, which separates the refrigerant output from the first evaporator into liquid and vapor. The vapor outlet from the phase separator is connected to a first inlet of the refrigerant flow control unit. The outlet of the refrigerant flow control unit is connected to the inlet of the compressor unit. The liquid outlet from the phase separator is connected to a second expansion device. In a specific example, the second expansion device is a capillary tube (capillary tube). The outlet of the capillary is connected to the inlet of the second evaporator. The outlet of the second evaporator is connected to the second inlet of the refrigerant flow control unit.

According to the present invention, the capillary connected to the inlet of the second evaporator is connected to the pipe connecting the outlet of the second evaporator to the second inlet of the refrigerant flow control unit, ie, the second evaporator suction line and the heat pipe. Arrange in a communication relationship. It is preferable to arrange the capillary and the second evaporator suction line in a countercurrent heat transfer relationship, that is, a relationship in which the refrigerant flowing through the capillary travels in the opposite direction to the flow of the refrigerant flowing through the second evaporator suction line.

In operation, the refrigerant flow control unit alternately flows refrigerant entering its first and second inlets to the compressor unit. The compressor unit compresses each refrigerant stream to the same pressure. The refrigerant or at least a part of the refrigerant circulates in the refrigerant device to perform energy transport. For example, in one embodiment, the first evaporator is at + 15 ° F (-9
C) to + 32 ° F (0 ° C) and cool the fresh food compartment between + 33 ° F (0 ° C) and + 47 ° F (8 ° C). The second evaporator is at -30 ° F (-34 ° C) to 0 ° F (-
17 ° C.) and freezer compartment at −10 ° F. (−23)
C) to + 15F (-9C).

The heat exchange arrangement between the capillary and the second evaporator suction line increases the specific cooling capacity in the second evaporator;
That is, the cooling capacity is restored. The term “ratio” means “per unit mass flow”. As a result of the increased specific cooling capacity in the second evaporator, less mechanical energy is required to operate the second evaporator at lower temperatures.

In order to further clarify such objects, configurations and effects of the present invention, the present invention will be specifically described below with reference to the accompanying drawings.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention, as described below,
It is considered to be most suitable for use in refrigeration equipment, especially home refrigerators. However, the invention can be used for other refrigeration applications, such as multiple air conditioning units.
Thus, as used herein, the term “refrigeration equipment” refers not only to refrigerators and refrigerators, but also to numerous other types of refrigeration applications.

FIG. 1 shows a first embodiment 100 of a refrigeration system. Apparatus 100 includes a compressor unit 102 and a condenser 104 coupled thereto. The first capillary tube 106 serves as the condenser 10
4 is connected to the outlet. Preferably, a filter and dryer 105, known in the art as a pickle, is located in the refrigerant flow passage between the condenser 104 and the capillary tube. The pickle 105 filters out particles from the refrigerant and absorbs moisture. A first evaporator 108 is shown coupled to the outlet of the first capillary tube 106. The outlet of the first evaporator 108 is connected to the inlet of the phase separator 110. The phase separator 110 comprises a screen 112, a vapor section 114 located near the phase separator inlet.
And a liquid portion 116. Steam part 11 of the phase separator
4 is coupled to the refrigerant flow control unit 118 as a first input. Line 120 is the vapor portion 114 of the phase separator.
To the control unit 118, and a line 120 is provided within the phase separator 110 where liquid refrigerant entering the vapor portion 114 of the phase separator passes through the vapor portion 114 and is connected to the line 120.
Are arranged so as not to be inserted into the open end. The outlet of the liquid portion 116 of the phase separator is connected to the second capillary 122. A second evaporator 124 is coupled to an outlet of the second capillary 122, and an outlet of the second evaporator 124 is coupled to the refrigerant flow control unit 118 as a second input.

The outlet of the refrigerant flow control unit 118 is connected to the compressor unit 102. Thermostat 1
26 receives the current from an external power supply indicated by “power input” 128 and is connected to the compressor unit 102.
When cooling is needed, thermostat 126 provides an output signal to energize compressor unit 102. Typically, the thermostat 126 is placed in a freezer compartment of a refrigerator. The compressor unit 102 operates only when the thermostat 126 indicates that cooling is needed. The arrangement of the control unit 118 determines the flow of the refrigerant flowing through each evaporator, as described later.

The evaporators 108 and 124 shown in FIG.
Is preferably a spine-finned evaporator well known in the art, and the compressor unit 102 is preferably a rotary compressor. For example, evaporators 108 and 124
Are placed in the fresh food compartment and the freezer compartment of the household refrigerator, respectively. The evaporators 108 and 124 are arranged such that excess liquid refrigerant flows out of the evaporator naturally.

The feature of the present invention resides in the heat transfer structure between the pipes. Specifically, in this embodiment, the second capillary 12
2 and a pipe 130, that is, a heat transfer structure between the suction line of the second evaporator 124. The second capillary 122 is arranged in a counter-current heat transfer relationship with the pipe 130. More specifically, the second capillary 122 is in thermal contact with the pipe 130. The thermal contact is made between, for example, the outer surface of the capillary 122 and the pipe 1.
Achieved by soldering side by side with a portion of 30. As a diagrammatic representation of the heat transfer relationship, the capillary 12
2 is shown as wrapped around piping 130. As described above, heat transfer is performed in a counter-flow (counter-flow) relationship. That is, the refrigerant flowing through the capillary 122 proceeds in a direction opposite to the flow of the refrigerant flowing through the pipe 130. As is well known in the art, using a countercurrent heat exchange arrangement, rather than a heat exchange arrangement in which both flows proceed in the same direction, increases heat exchange efficiency. Details of the effect obtained by this heat transfer structure will be described with reference to FIGS. Note that in another embodiment (not shown), the capillary 122
It is also conceivable to arrange the capillaries 122 such that the flow of the gas and the flow of the pipe 130 proceed in the same direction.

The first capillary 106 is connected to pipes 120 and 13
0 and are arranged in a countercurrent heat exchange relationship. Thermal contact can be made, for example, with the outer surface of the capillary 106 and the tubing 120 and 130.
It is achieved by arranging and soldering some of the parts together. As a diagrammatic representation of the heat transfer relationship, the capillary tube 106 is shown as being wrapped around pipes 120 and 130. Heat transfer takes place in countercurrent relationship. That is,
Refrigerant flowing through the capillary 106 is supplied to pipes 120 and 130.
Flows in the opposite direction to the flow of the refrigerant flowing through.

In addition to the components described above, the device 100 includes a liquid separator (accumulator) 134. Liquid separator 1
34 is located at the outlet of the second evaporator 124 and in the freezer compartment. FIG. 1 also shows a pressure sensor 138. The pressure sensor 138 is disposed between the heat exchange arrangement of the capillary 106 and the pipe 120 and the control unit 118 at a position that generates a signal representing the pressure of the refrigerant flowing through the pipe 120. As described later, the operation of the control unit 118 is controlled using an output signal from the pressure sensor 138.

Reference is now made to FIG. FIG. 2 shows the liquid separator 1
34 is a detailed view of FIG. The liquid separator 134 is the second evaporator 12
4, and supplies the vapor refrigerant to the compressor unit 102 via the control unit 118.
An internal transport line extraction hole 136 is provided to prevent stagnation of lubricating oil when cycle conditions change, for example, when superheated steam is discharged from second evaporator 124.

When the second evaporator 124 operates at a temperature below the specification temperature, for example, due to a reduced thermal load or due to the setting of the chamber thermostat, some liquid will Is discharged from Liquid separator 134
Means that the liquid discharged from the second evaporator 124
To prevent loss of cooling capacity resulting from evaporation. Specifically, the liquid discharged from the second evaporator 124 is stored in the liquid separator 134. The steam discharged from the second evaporator 124 passes through the pipe 130. Second evaporator 12
4 is overheated, the liquid separator 13
The refrigerant liquid stored in 4 evaporates in liquid separator 134 and flows to pipe 130. Thus, the liquid separator 1
Numeral 34 prevents the cooling capacity of the second evaporator 124 from being lost.

FIG. 3 diagrammatically shows the refrigerant flow control unit 118. Two input pipes 120 and 130 are formed integrally with the control unit 118. Output piping 13
2 is also shown as being formed integrally with the control unit 118. Input piping 120, 130 and output piping 1
Rather than forming unit 32 integrally with control unit 118, in another embodiment (not shown), these tubing may be connected to the inlet and outlet of control unit 118, respectively, by welding, soldering, mechanical joints, or the like. May be. The control unit 118 includes a controllable valve 140 consisting of a solenoid operated valve. If the solenoid control valve is, for example, IS
I Hydraulic Power Company (ISI FluidPower Inc.,
(Michigan, USA). A valve from ISI Hydraulics is modified by removing the housing gasket and hermetically sealing the housing so that a refrigerant can be used. A controllable valve 140 is used to control the fluid flow through the input pipe 120. Typically, a higher pressure refrigerant flows through the input pipe 120 than the pipe 130. A check valve 142 is arranged in the input pipe 130. The check valve 142 includes a ball 144 and a ball seat 146.
And a basket 148.

In operation, the controllable valve 140 is opened and closed via the pressure sensor 138 (FIG. 1). The timing of power output from the pressure sensor 138 to the solenoid of the controllable valve 140 is determined by the pressure of the refrigerant in the pipe 120. When the valve 140 is closed, the low pressure refrigerant in the pipe 130 pushes open the check valve 142, and the low pressure refrigerant flows from the pipe 130 to the output pipe 132. This state is called “state 1”. When valve 140 opens and allows refrigerant to pass therethrough, high pressure refrigerant from line 120 closes check valve 142 and check valve 142 remains closed while high pressure refrigerant continues to flow from line 120 to output line 132. Up to. This state is called “state 2”.

More specifically, during operation, the refrigerant R
When -12 (dichlorodifluoromethane) is used, the refrigerant in the pipe 130 is 20 psia (pound per
In square inch absolute, the refrigerant in the pipe 120 is 40 psia. When the control unit 118 is in "State 1", the inlet pressure to the compressor unit 102 is about 20 psia. Control unit 118
Is "State 2", the inlet pressure to the compressor unit 102 is about 40 psia.

The pressure switch 138 is used to control a particular state or location of the control unit 118. For example,
If it is preferred to maintain the refrigerant in the first evaporator 108 at about + 34 ° F (1 ° C), the temperature of the refrigerant in the first evaporator 108 should be about + 26 ° F (-3 ° C) to + 36 ° F ( 2
(° C.) is an appropriate range. As shown by the position of the pressure sensor 138 in FIG.
By sensing the pressure of the refrigerant in the pipe 120 near 8, there is a one-to-one correspondence between the sensed pressure and the temperature of the refrigerant in the first evaporator 108. The pressure sensed by the pressure sensor 138 indicates that the temperature of the refrigerant in the first evaporator 108 is +3.
When indicating greater than 6 ° F. (2 ° C.), the output signal of the pressure sensor activates the control unit 118, for example, by energizing the controllable valve 140, and thus the pipe 120 and the pipe 132. Establish flow communication, ie, “State 2”.

Even if flow communication is established between the pipe 120 and the pipe 132, the refrigerant is sucked through the first evaporator 108 because the thermostat 126 detects that the freezing room needs to be cooled, and Only when unit 102 is energized. For example, the air temperature of the freezer is set to about 0 ° F (−
17 ° C.), it is required to be maintained at −2 ° F. (−18 ° C.) to +
The temperature range of 2 ° F. (−16 ° C.) is a typical range as the air temperature of the freezer compartment. + 2 ° F air temperature in freezer compartment
If so, the thermostat 126 indicates to power the compressor unit 102.
Following energization of compressor unit 102, thermostat 126 turns off power to compressor unit 102 when the air temperature in the freezer compartment drops below -2 ° F (-18 ° C).
When the compressor unit 102 is not energized, regardless of the location of the control unit 118, the fresh food compartment and the freezer compartment have substantially no refrigeration effect.

The temperature of the refrigerant in the pipe 120 is + 36 ° F.
(2 ° C.) or higher and the freezer temperature is + 2 ° F. (−16
° C) or more, the control unit 118 operates as “state 2”.
, The compressor unit 102 is energized. The temperature of the refrigerant in the fresh food room evaporator 108 is + 26 ° F (-3 ° C)
When the pressure becomes below, the pressure sensor 138
8 to “STATE 1”. Then, the refrigerant is sucked through the freezer evaporator 124 until the temperature of the freezer becomes −2 ° F. (−18 ° C.) or less. Control unit 118
Is in the "state 1", the refrigerant is sucked through the fresh food room evaporator 108 at a lower speed than when the control unit 118 is in the "state 2". In order to suck the refrigerant through the freezer evaporator 124, the temperature of the refrigerant in the pipe 120 must be equal to or lower than + 36 ° F (2 ° C) and the temperature of the freezer must be equal to or higher than + 2 ° F (-16 ° C). .

The device 100 shown in FIG. 1 and described above
General Electric's home refrigerator model N
o. General Electric Company's N for TBX25Z
o. It was actually installed together with the 800 rotation compressor. In the cycle operation of the compressor unit, the ON time was 22.7 minutes and the OFF time was 33.5 minutes (40.4% ON time). A fan (not shown) was provided for each evaporator, and air was blown to the coil of each evaporator. Each fan is coupled to a power supply via a thermostat 126 and the thermostat 12
When 6 powered compressor unit 102, both fans were also powered, blowing air on evaporators 108 and 124, respectively.

FIGS. 4 and 5 are temperature-enthalpy diagrams. The graph of FIG. 4 is similar to the circuit 100 shown in FIG. 1, but is for a refrigeration circuit in which the capillary 122 and the pipe 130 are not arranged in a heat transfer relationship. The graph of FIG. 5 incorporates one embodiment of the heat transfer structure according to the present invention, ie, as shown in FIG.
This is for a refrigeration circuit 100 in which 30 is arranged in a heat transfer relationship.

More specifically, in FIG. 4, the x-axis represents enthalpy (h) and the y-axis represents temperature (T). The circuit analyzed in FIG. 4 corresponds to the refrigeration circuit shown in FIG. 1 except that the capillary 122 and the pipe 130, that is, the freezer evaporator suction line are not arranged in a heat transfer relationship. On the y-axis, the temperature T of the air in the evaporator of the fresh food compartment
_FFair and the air temperature T _FZair of the freezer evaporator are shown. Point (1) on the graph indicates the state of the refrigerant at the outlet of the condenser 104. Point (2) shows the state of the refrigerant within capillary tube 106 but at the end of thermal contact with pipes 120 and 130. Point (3) is the point where the outlet of the capillary tube 106 and the first evaporator 1
08 shows the state of the refrigerant between the inlet and the inlet of No. 08. Point (4) is the first
The state of the refrigerant at the outlet of the evaporator 108 is shown. Point (5) shows the state of the refrigerant at the outlet of the phase separator vapor portion 114.
Point (6) shows the state of the refrigerant at the outlet of the phase separator liquid portion 116. Point (7) shows the state of the refrigerant at the outlet of the capillary 122 (in this example, the capillary 122 is connected to the pipe 13
0 has no heat transfer relationship). Point (8) shows the state of the refrigerant at the outlet of the liquid separator 134. Point (9) is the capillary 106
5 shows a state of the refrigerant in the pipe 130 at the end of the thermal contact with the refrigerant. Point (10) indicates the state of the refrigerant from the pipe 130 at the entrance to the compression chamber of the compressor unit 102. Point (1
1) shows the state of the refrigerant from the pipe 130 at the outlet of the compression chamber of the compressor unit 102. The point (12) is a pipe 130 at the outlet of the compressor motor chamber of the compressor unit 102.
Shows the state of the refrigerant from. Point (13) is the capillary 106
5 shows a state of the refrigerant in the pipe 120 at the end of the thermal contact with the refrigerant. Point (14) shows the state of the refrigerant from the pipe 120 at the entrance of the compression chamber of the compressor unit 102. Point (15)
Is the pipe 12 at the outlet of the compression chamber of the compressor unit 102
Indicates the state of the refrigerant from zero. Point (16) indicates the state of the refrigerant from the pipe 120 at the outlet of the compressor motor chamber of the compressor unit 102.

The temperature-enthalpy graph of FIG. 4 is shown to make it easier to change the thermodynamic advantages of the present invention. In particular, comparing the graph of FIG. 4 with the graph of FIG. 5, it is clear that the specific cooling capacity of the freezer evaporator achieved by the present invention is increased or recovered.

More specifically, the circuit analyzed in FIG. 5 incorporates one embodiment of the heat transfer structure according to the present invention, ie, as shown in FIG. 1, the capillary 122 and the pipe 130 are arranged in a heat transfer relationship. Refrigeration circuit.
The points and numbers shown in FIG. 4 are also shown in FIG. 5 to facilitate comparison of thermodynamic properties. the y-axis, the fresh food evaporator temperature T _FFair the freezer compartment evaporator of the air the air temperature T _FZair
Is shown. Point (1) on the graph indicates the state of the refrigerant at the outlet of the condenser 104. Point (2) is for pipes 120 and 13
The state of the refrigerant in the capillary tube 106 at the end of the thermal contact with zero is shown. Point (3) is the point where the outlet of the capillary tube 106 and the first evaporator 1
08 shows the state of the refrigerant between the inlet and the inlet of No. 08. Point (4) is the first
The state of the refrigerant at the outlet of the evaporator 108 is shown. Point (5) shows the state of the refrigerant at the outlet of the phase separator vapor portion 114.
Point (6) shows the state of the refrigerant at the outlet of the phase separator liquid portion 116.

The point (7 ') indicates the state of the refrigerant at the outlet of the capillary tube 122 (in this example, the capillary tube 122 has a heat transfer relationship with the pipe 130). Point (8) is the liquid separator 13
4 shows the state of the refrigerant at the outlet of FIG. The point (9 ') indicates the state of the refrigerant in the pipe 130 at the end of the thermal contact with the capillary 106. The point (10 ') indicates the state of the refrigerant from the pipe 130 at the entrance to the compression chamber of the compressor unit 102. The point (11 ′) indicates the state of the refrigerant from the pipe 130 at the outlet of the compression chamber of the compressor unit 102. Point (12 ')
Shows the state of the refrigerant from the pipe 130 at the outlet of the compressor motor chamber of the compressor unit 102. Point (13) shows the state of the refrigerant from the pipe 120 at the end of the thermal contact with the capillary 106. Point (14) shows the state of the refrigerant from the pipe 120 at the inlet of the compression chamber of the compressor unit 102.
Point (15) shows the state of the refrigerant from the pipe 120 at the outlet of the compression chamber of the compressor unit 102. Point (16) is
The state of the refrigerant from the pipe 120 at the outlet of the compressor motor chamber of the compressor unit 102 is shown.

With the heat transfer structure according to the present invention, the specific cooling capacity of the freezer evaporator 124 is increased. As the specific cooling capacity increases, the amount of mechanical energy required to cool the freezer evaporator decreases. The increase in cooling capacity actually obtained depends, of course, on the actual mass flow through the freezer evaporator. To explain this point in detail, with reference to FIG. 4, the mass flow rate m is expressed as follows.

_{M T} = total mass flow ml _L = mass flow flowing to freezer evaporator 124 m _H = mass flow to fresh food compartment evaporator 108 The following equation (1) holds for the apparatus of FIG.

( _{M T} ) (△ ha) = m _L (h9−h8) + m _H (h13−h5) (1) Here, △ ha = h1−h2. The enthalpy (h) is related to the respective mass flow to give a specific cooling capacity. Equation (1) indicates that the change in the enthalpy (Δha) of the refrigerant from the inlet to the outlet of the capillary 106 (Δha) —the change in the enthalpy (Δha) is obtained by the capillary 106 and the pipe 12.
0, 130 resulting from the heat transfer between the capillary 1
It shows that it is equal to the change in the enthalpy of the refrigerant in the pipes 120 and 130 from the beginning to the end of the thermal contact with 06. As a result of the heat transfer, the fresh food compartment evaporator 108
The recovery of the specific cooling capacity at the time is [(m _H ) (△ h
a)]. As a result of the heat transfer with the capillaries 106, there is no regain of the specific cooling capacity in the freezer evaporator 124.

Using the heat transfer of the present invention, as shown in FIG. 5, equation (1) becomes the following equation (2).

(M _T ) (△ ha) = m _L (h9′−h8) + m _H (h13−h5) (2) Here, Δhb = (h9′−h8). If QL
Is equal to the amount of cooling supplied to the freezing compartment, the following equation (3) holds without the heat transfer structure of the present invention, that is, with respect to the graph of FIG.

QL = _mL (h8−h7) (3) However, with the heat transfer structure of the present invention, the cooling supply amount QL ′ to the freezing compartment is calculated by the following equation (4) as shown in FIG. become.

QL ′ = _mL (h8−h7 ′) (4) Accordingly, the present invention increases the specific cooling capacity of the freezer evaporator 124 by adding _mL (h7−h7 ′). Of course, the actual increase in the cooling capacity depends on the mass flow rate of the refrigerant flowing to the freezer evaporator 124. The increased cooling capacity also reduces the mechanical energy required to cool the freezer. Specifically, since the amount of cooling provided by the freezing compartment evaporator 124 during operation increases, the operation time of the compressor unit required to satisfy the cooling requirement of the freezing compartment is shortened.

FIG. 6 is a schematic block diagram of a home refrigerator 200 including a heat insulating wall 202 defining a fresh food compartment 204 and a freezing (freezer) compartment 206. FIG. 5 is for illustration purposes only and illustrates an apparatus having a plurality of substantially separate chambers requiring refrigeration (cooling) at different temperatures. In the home refrigerator, the fresh food room 204 is increased by about +3.
Maintain 3 ° F. to + 47 ° F. and keep freezer 206 at −10 °
Typically, it is maintained between F and + 15 ° F.

The first evaporator 208 is shown as being located in the fresh food compartment 204 and the second evaporator 210 is being located in the freezer compartment 206. The present invention does not limit the physical arrangement of the evaporator, and the evaporator arrangement shown in FIG. 5 has been presented for illustrative purposes only, and for ease of understanding. The evaporators 208 and 210 may be located anywhere in the home refrigerator or external to the refrigerator, and the evaporator cooling air from each evaporator may be guided to the corresponding room through piping, barriers, or the like. I just need.

First evaporator 208 and second evaporator 210
Is driven by a compressor unit 212 and a condenser 214 arranged in a compressor / condenser chamber 216. First temperature sensor 218, such as thermostat 126 shown in FIG.
Is placed in the freezer 206. Of course, this sensor 218
Is preferably adjustable by the user to allow the user of the device to select the temperature or temperature range at which the compressor should be energized and / or deactivated. Typically, the first evaporator 20
8 at about + 15 ° F. to + 32 ° F., the second evaporator 210 at about −30 ° F. to 0 ° F., and freezing the fresh food compartment 204 to about + 33 ° F. to + 47 ° F. Room 206
Is maintained between about −10 ° F. and + 15 ° F.

FIG. 7 shows a second embodiment of the present invention using three or more evaporators. The use of more than two evaporators is even more efficient in some situations. For example, in some cases it may be desirable to provide a third refrigerator in a home refrigerator to rapidly cool or freeze certain items in another room.

Specifically, embodiment 300 includes a compressor unit 302 and a condenser 304 coupled thereto. The outlet of the condenser 304 is connected to the first expansion valve 306, and the outlet of the first expansion valve 306 is connected to the first evaporator 308.
The outlet of the first evaporator 308 is connected to the inlet of the first phase separator 310. The first phase separator 310 includes a screen 3
12, including a vapor portion 314 and a liquid portion 316. The vapor portion 314 of the phase separator 310 is coupled to the refrigerant flow control unit 318 as a first input. Specifically, a pipe 320 extends from the vapor phase 314 of the first phase separator to the control unit 318, and the pipe 320 has a liquid refrigerant entering the phase separator vapor section 314 within the vapor phase section 314. It is arranged so as to pass through 314 and not enter the open end of the pipe 320. Liquid part 31 of the first phase separator
The outlet of 6 is connected to the first capillary tube 322. An inlet of the second evaporator 324 is connected to an outlet of the first capillary tube 322, and an outlet of the second evaporator 324 is connected to an inlet of the second phase separator 326. Second phase separator 326 includes a screen 328, a vapor portion 330 and a liquid portion 332. The vapor portion 330 of the phase separator 326 is coupled as a second input to the refrigerant flow control unit 318. Specifically, a pipe 334 extends from the vapor portion 330 of the second phase separator to the control unit 318, and the pipe 334 has a liquid refrigerant entering the phase separator vapor portion 330 within the phase separator 326. It is arranged so as to pass through 330 and not enter the open end of the pipe 334. The outlet of the liquid portion 332 of the second phase separator is connected to a second capillary 336. An inlet of the third evaporator 338 is connected to an outlet of the second capillary 336, and an outlet of the third evaporator 338 is connected to the refrigerant flow control unit 318 as a third input.

For example, using first sensor 340 and second sensor 342, the physical attributes of first evaporator 308 and second evaporator 324 are detected, or the physical attributes of the refrigerant flowing through the respective evaporators are determined. To detect. These sensors 340 and 342 are, for example, pressure, temperature, flow and / or density sensors. For example, each pressure sensor is coupled anywhere along the length of evaporator 308 and 324, for example, to the outlet of each evaporator.
Preferably, each temperature sensor is located at a location along the length of each evaporator through which the two-phase refrigerant flows. First sensor 340 and second sensor 342 are coupled to timer 344. This timer 344 is a variable timer. Instead of the timer 344, a sensor switch can be used. In another embodiment, the control unit 318 can be driven using a fixed timer. In the fixed timer embodiment, of course, sensors 340 and 342 are not required. Sensors 340 and 342 are preferably user adjustable.

The control unit 318 shown in FIG.
Controllable valve 346 and second controllable valve 348
including. Specifically, these valves 346 and 348
Is preferably an on-off solenoid valve well known in the art. The control unit 318 further includes a check valve 350
including. First and second controllable valves 346 and 348
Receive, as inputs, refrigerant flowing in pipes 320 and 334, respectively. A pipe 352 connected to the third evaporator 338 supplies the input refrigerant to the check valve 350.

In operation, the valves of the control unit 318 alternately open to allow refrigerant to flow through the respective evaporators to the compressor unit 302. For example, the first valve 3
When 46 is open and the second valve 348 is closed, the refrigerant flows through the first evaporator 308 to the phase separator 310 and through the pipe 320 to the compressor unit 302. At this time, the refrigerant does not flow to the second evaporator 324 or the third evaporator 338.

Similarly, the first valve 346 is closed and the second valve 3 is closed.
When 48 is open, refrigerant flows from liquid portion 316 of phase separator 310 to expansion device 322 and second evaporator 324.
To the phase separator 326 and to the compressor unit 302 via line 334. At this time, the vapor refrigerant is supplied from both the first phase separator 310 and the third evaporator 338.
It does not flow to the compressor unit 302. At this time, the refrigerant is
It flows from the condenser 304 through the first evaporator 308.

When both valves 346 and 348 are closed, the third valve 350 is automatically opened and liquid refrigerant flows from the liquid portion 332 of the second phase separator to the expansion device 336 and then to the third evaporator 338. Through the compressor unit 302. At this time, the refrigerant also flows to the first evaporator 308 and the second evaporator 324.

Relatively high-pressure refrigerant flows through the pipe 320, medium-pressure refrigerant flows through the pipe 334, and low-pressure refrigerant flows through the pipe 352. The timer 344 is controlled by the control unit 318
Control of the duty cycle (operating cycle). The particular duty cycle chosen will, of course, depend on the desired operating parameters of each evaporator. Note that the timer 344 activates the valves 346 and 348, whether these valves alternately open,
Control so that both can be closed but not opened at the same time. Of course, a thermostat (not shown) is usually provided to control the bias of the compressor unit 302.

The first evaporator 308 operates at a temperature higher than the operating temperatures of the second evaporator 324 and the third evaporator 338. The third evaporator 338 includes the first evaporator 308 and the second
It operates at a temperature lower than the operating temperature of the evaporator 324. Second
The evaporator 324 includes the first evaporator 308 and the third evaporator 3
It operates at an intermediate temperature of 38 operating temperatures.

According to the present invention, the pipe 352, that is, the suction line of the third evaporator 338 is arranged in a countercurrent heat transfer relationship with the second capillary 336 and the first capillary 322. In the embodiment of FIG. 6 of the present invention, the specific cooling capacity is recovered in the third evaporator 338 in the same manner as the recovery of the specific cooling capacity described with reference to the embodiment of the present invention shown in FIG. However, in the embodiment of FIG. 7, the pipe 352 is connected to the first capillary 322.
And by placing it in countercurrent heat transfer relationship with both the second capillary 336, additional specific cooling capacity can be regained.

FIG. 8 shows a third embodiment 400 of a refrigerating apparatus incorporating the third embodiment of the heat transfer structure of the present invention. Specifically, the refrigeration apparatus 400 includes a first compressor unit 402 and a second compressor unit 404, and the outlet of the first compressor unit 402 is connected to the second compressor unit 4
04 is connected to the entrance. The first capillary 406 is the second
Coupled to the outlet of the compressor unit 404, the first capillary 4
The outlet of 06 is connected to the inlet of the first expansion device 408. The outlet of the first expansion device 408 is connected to the inlet of the first evaporator 410, and the outlet of the first evaporator 410 is connected to the phase separator 41.
2 inlets. The phase separator 412 comprises a screen 414 located near the phase separator inlet,
16 and a liquid portion 418. The outlet of the vapor portion 416 of the phase separator 412 is connected to a pipe 420 disposed between and connecting the first compressor unit 402 and the second compressor unit 404. Liquid part 41
8 is connected to the second capillary 422. Second capillary 4
The outlet of 22 is connected to the inlet of the second evaporator 424. The outlet of the second evaporator 424 is connected to a liquid separator (accumulator) 426, and the outlet of the liquid separator 426 is connected to the pipe 4.
28 to the inlet of the first compressor unit 402. The liquid separator 426 is the liquid separator 13 shown in FIG.
It operates similarly to 4. Specifically, the liquid separator 426 is the same as the liquid separator 134 shown in detail in FIG. The liquid refrigerant discharged from the second evaporator 424 is stored in the liquid separator 426, and thereafter the liquid refrigerant is evaporated by, for example, discharging the superheated refrigerant from the second evaporator 424.

In the embodiment of FIG. 8 of the present invention, the specific cooling capacity is recovered in the second evaporator 424 in the same manner as the recovery of the specific cooling capacity described for the embodiment of the present invention shown in FIG. Specifically, the second evaporator 424 is arranged by arranging the pipe 428 in the countercurrent heat transfer relation with the capillary 422.
To achieve the recovery of the specific cooling capacity at Embodiment 4 of FIG.
The reason for giving 00 is mainly to show an example in which the present invention is applied to a refrigeration circuit including a plurality of compressors or one compressor having a plurality of stages.

It should be noted that depending on the refrigeration system, not all of the energy efficiency and cost reduction according to the present invention is absolutely necessary. Therefore, the invention as described herein can be modified, and such a modification will change the efficiency and increase the cost as compared with the embodiment described above. For example, a plurality of compressors or a multi-stage compressor or a combination thereof can be used with refrigerant flow control means. Such modifications are possible and are considered to be within the scope of the present invention. Further, while the invention has been described in connection with a home refrigerator, the invention is not limited to incorporating or combining with a home refrigerator.

While the various preferred embodiments have been illustrated and described, numerous modifications or alterations, variations, in whole or in part, are possible.
Obviously, substitutions and equivalents can be made without departing from the spirit of the invention.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a refrigeration apparatus of the present invention incorporating a heat transfer structure.

FIG. 2 is a detailed view of a liquid separator used in the embodiment of the refrigeration apparatus of FIG.

FIG. 3 is a diagram illustrating an example of a refrigerant flow control unit used in the embodiment of the refrigeration apparatus of FIG. 1;

FIG. 4 is a temperature-enthalpy graph for a refrigeration circuit having no heat transfer structure.

5 is a temperature-enthalpy graph for a refrigeration circuit having the heat transfer structure shown in FIG.

FIG. 6 is a block diagram of a home refrigerator.

FIG. 7 is a diagram showing a second embodiment of the refrigeration apparatus of the present invention incorporating a heat transfer structure.

FIG. 8 is a diagram showing a third embodiment of the refrigeration apparatus of the present invention incorporating a heat transfer structure.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Refrigeration unit 102 Compressor unit 104 Condenser 106 Capillary tube 108 First evaporator 110 Phase separator 114 Vapor part 116 Liquid part 118 Refrigerant flow control unit 120 Pipe 122 Second capillary 124 Second evaporator 126 Thermostat 128 Power input 130 Pipe 132 plumbing

──────────────────────────────────────────────────続 き Continued on the front page (56) References US Patent 4,918,942 (US, A) UK Patent 639691, (GB, B) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 5/00-5 / 04 F25B 40/00-41/04

Claims (8)

(57) [Claims] A compressor means; a high-temperature evaporator; a low-temperature evaporator operating at a lower temperature than the high-temperature evaporator; a first piping means coupled to an inlet of the low-temperature evaporator; A second piping means disposed in a first heat transfer relationship with the first piping means and coupled to an outlet of the low temperature evaporator; and the high temperature evaporator and the low temperature in relation to a refrigerant flow with the compressor means. A flow control unit that can be repeatedly and alternately connected to the evaporator, and includes a flow control unit connected to receive at least a part of the refrigerant discharged from the high-temperature evaporator and the low-temperature evaporator; A refrigeration circuit, comprising: a control valve disposed on a pipe connecting the section and the high-temperature evaporator; and a check valve disposed on a pipe connecting the flow control section and the low-temperature evaporator. . A condenser coupled to receive refrigerant discharged from said compressor means, wherein said high temperature evaporator is connected to receive a portion of refrigerant discharged from said condenser. The low-temperature evaporator is connected to receive a part of the refrigerant discharged from the high-temperature evaporator, and the second piping unit connects an outlet of the low-temperature evaporator to the flow control unit. The refrigeration circuit according to claim 1, wherein: 3. The refrigeration circuit according to claim 1, wherein the first heat transfer arrangement is arranged in a counter-current heat transfer relationship. 4. A liquid separator according to claim 1, wherein a liquid separator is arranged between the low-temperature evaporator and the first heat transfer arrangement in the second piping means. Refrigeration circuit. 5. The refrigeration circuit according to claim 1, wherein said first piping means includes a capillary tube forming a part of said first heat transfer arrangement. 6. A third pipe means coupled to the inlet of the high-temperature evaporator from the condenser, wherein the second pipe means is in a second heat transfer relationship with at least a portion of the third pipe means. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is arranged. 7. The refrigeration circuit of claim 6, wherein said second heat transfer arrangement is arranged in a counter-current heat transfer relationship. 8. The refrigeration circuit according to claim 6, wherein said third piping means includes a capillary tube forming a part of said second heat transfer arrangement.