JPH0349034B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Field of Application) The present invention relates to a refrigerator, and particularly to an improvement in a refrigerator equipped with an electrically operated expansion valve whose opening degree can be adjusted as an expansion mechanism. (Prior Art) Conventionally, as disclosed in Japanese Patent Publication No. 58-47628, this type of refrigerator has conventionally used a thermoelectric electric expansion valve with adjustable opening, and a thermoelectric expansion valve that controls refrigerant at the outlet of the evaporator. a detection means for detecting the degree of superheat; and a control means for receiving a signal from the detection means and controlling the valve opening degree of the electric expansion valve according to the degree of superheat; It is known that the refrigerant flow rate control is maintained at a predetermined value. (Problem to be Solved by the Invention) However, when starting operation in various operation modes, such as during cooling operation, heating operation, or when the number of rooms to be air-conditioned is different even in the same operation state, the above-mentioned conventional In this case, the initial valve opening of the electric expansion valve is uniformly fully closed, regardless of the difference in operation mode, and the valve opening is significantly different from the appropriate valve opening when operation is stable depending on the subsequent operation mode. Due to its location, the range of increase in the valve opening of the electric expansion valve that must be controlled during operation is large, and it takes a relatively long time to stabilize and converge to the appropriate valve opening, resulting in early stability of the refrigeration capacity. It lacks. In view of this, the present invention is an electric expansion valve that can relatively easily control the valve opening, and as a specific example, the change in the valve opening corresponds 1:1 to the number of driving pulses for controlling the valve opening. We focused on the fact that there is a stepping motor-type type that uses a stepping motor, and the purpose of this is to use the electric expansion valve described above and to adjust the valve opening of the electric expansion valve in advance when starting operation in various operation modes. Prior to operation, the valve opening is initially set to the appropriate valve opening corresponding to the operation mode at startup determined by tests, etc., and this initial setting value is rewritten to the appropriate value for each operation. To reduce the range of increase/decrease in the valve opening of an electric expansion valve to be controlled, and to satisfactorily stabilize convergence to a proper valve opening in a short time no matter what operating mode the valve is operated in. (Means for Solving the Problems) In order to achieve the above object, the configuration of the present invention is as shown in FIG.
1, a detection means 55 for detecting the degree of superheating or supercooling of the refrigerant after passing through the heat exchangers 2 to 5; In the refrigerator, which is equipped with a control means 56 for controlling the valve opening degree of the electric expansion valve V1, and is configured to maintain the degree of superheating or subcooling in the heat exchanger 3 at a predetermined value, when the refrigerator starts operating. an operation start detection means 57 for detecting the operation start time, an operation mode determination means 58 for determining the operation mode of the refrigerator, and a memory for storing in advance the initial setting values of the electric expansion valves V1 to V4 according to the operation mode of the refrigerator. means 59; reading means 60 which receives the signal from the operation mode determining means 58 and reads out the initial setting value corresponding to the operation mode from the storage means 59; Valve V1~V
initial setting means 61 for positioning the valve opening degree of No. 4 to the initial setting value read out by the reading means 60;
and a rewriting means 62 for rewriting each initial setting value stored in the storage means 59 to the valve opening degree when the operation is stable each time the refrigerator is operated. (Function) With the above configuration, in the present invention, when starting the operation of the refrigerator, after reading out the initial setting value corresponding to the operation mode from among the initial setting values stored in advance corresponding to various operation modes, Initialize the valve opening degree to the read initial setting value, and
The above-mentioned initial setting value is successively learned for each operation and corrected toward the optimum opening value. (Effects of the Invention) Therefore, according to the refrigerator equipped with the electric expansion valve of the present invention, when the refrigerator starts operating in various operation modes, the valve opening degree of the electric expansion valve can be determined by the reading means. It is initialized to the read initial setting value corresponding to the current operation mode, and the initial setting value of the opening degree is gradually corrected by learning toward the appropriate opening value for each operation, so in any operation mode. Even during operation, the range of increase/decrease in the valve opening of the electric expansion valve to be controlled during operation is further reduced for each operation, and convergence to the appropriate valve opening according to the operation mode of the electric expansion valve is achieved. The control can be performed more efficiently in a shorter time, and therefore the convergence stability of the valve opening can be dramatically improved, and the refrigerating capacity can be stabilized at an early stage. (Example) Hereinafter, an example of the present invention will be described in detail based on the drawings from FIG. 2 onwards. Figure 2 shows an embodiment in which the present invention is applied to a heat pump type air-conditioning/heating water heater, where A is an outdoor unit installed outdoors, and B, C, and D are installed in different rooms indoors. The indoor unit E is a hot water storage tank unit, and the outdoor unit A is equipped with a compressor 1 and a heat source side heat exchanger 2 inside, and the indoor units B, C,
D has air conditioning load side heat exchangers 3, 4,
5. The hot water storage tank unit E also includes a hot water storage tank 6 that stores water therein, a hot water supply load side heat exchanger 7 that heats the water stored in the hot water storage tank 6, and a hot water supply load side heat exchanger 7 that heats the water stored in the hot water storage tank 6. A pump P for circulating the heat to the side heat exchanger 7 is provided. In the above outdoor unit A, SV1 and
SV2 is a four-way switching valve that switches as shown by the solid line when OFF, and switches as shown by the broken line when ON, SV3 is an electromagnetic on-off valve that allows refrigerant to flow from receiver 8 to hot water supply load side heat exchanger 7, and V ₁ ,V ₂ ,
V ₃ , V ₄ and V ₅ are stepping motor electric expansion valves that can be opened/closed and their opening degrees adjusted, respectively.
The electric expansion valves V1 to V5 each have a change in valve opening corresponding to the number of drive pulses as a valve opening control signal generated by a CPU 42, which will be described later, in a 1:1 ratio. In addition, TH1 connects the liquid pipe 15 between the electric expansion valve V4 and the receiver 8 and the return gas pipe 23 to the compressor 1 in the first bypass pipe 36 with a capillary tube 27 interposed therebetween. The first temperature sensor is a thermistor installed on the return gas pipe 23 side of the capillary tube 27, and is for detecting the evaporation temperature (T ₁ ) during the refrigeration cycle. A common gas pipe 16 between the heat exchangers 3 to 5 and the four-way switching valve SV2, and branch liquid pipes ₂₀ , ₂₁ , ₂ on the indoor units B, C, and D sides of the electric expansion valves V1, V2, and V3.
It consists of a thermistor provided between the auxiliary condenser 37 and the capillary tube 28 in the second bypass pipe 39, which is connected to the auxiliary condenser 37, the capillary tube 28, and the check valve 38. The second temperature sensor is for making it possible to detect the condensation temperature (T ₂ ) of the air conditioning load side heat exchangers 3, 4, 5 on the outdoor side during heating operation, and
TH3 to TH10 are third to tenth temperature sensors each consisting of a thermistor as described above,
The third to fifth temperature sensors TH3 to TH5 are installed in the branch gas pipes 17 to 19 between the air conditioning load side heat exchangers 3 to 5 and the four-way switching valve SV2, respectively, and are used for low-pressure gas during cooling operation and cooling hot water supply operation. It detects the refrigerant temperature (T ₃ ), (T ₄ ), and (T ₅ ) of the refrigerant, and the sixth to eighth temperature sensors TH6 to TH8 are connected between the air conditioning load side heat exchangers 3 to 5 and the receiver 8, respectively. The refrigerant temperature (T ₆ ), (T ₇ ), (T ₈ ) of the high-pressure liquid refrigerant after condensation and liquefaction during heating operation and hot water supply operation is detected. Further, the ninth temperature sensor TH9 detects the refrigerant temperature (T ₉ ) of the return gas pipe 23 to the compressor 1, and the ninth temperature sensor TH10 detects the refrigerant temperature (T 9 ) of the return gas pipe 23 of the compressor 1.
This is to detect the refrigerant temperature (T ₁₀ ) of No. 4. Therefore, when each of the air conditioning load side heat exchangers 3 to 5 acts as an evaporator, the first temperature sensor TH1
The evaporation temperature (T ₁ ) is determined by the third to fifth temperature sensors TH3 to TH5, and the refrigerant temperature (T 3 ), (T ₄ ) of the low-pressure gas refrigerant after passing through each air conditioning load side heat exchanger 3 to 5 is determined by the third to fifth temperature sensors TH3 to _TH5 . , (T ₅ ), and conversely, when each air conditioning load side heat exchanger 3 to 5 acts as a condenser, the condensation temperature (T ₂ ) is detected by the second temperature sensor TH2.
and the sixth to eighth temperature sensors TH6 to TH8
The refrigerant temperatures (T ₆ ), (T ₇ ), and (T ₈ ) of the high-pressure liquid refrigerant after passing through each of the air conditioning load side heat exchangers 3 to 5 are detected, and the heat source side heat exchanger 2 acts as an evaporator. When activated, the first temperature sensor TH1 detects the evaporation temperature (T ₁ ), and the ninth temperature sensor TH9 detects the refrigerant temperature (T ₉ ) of the low-pressure gas refrigerant after passing through the heat source side heat exchanger 2. I have to. still,
In the figure, 29 is a capillary tube, 30 is a one-way valve that allows refrigerant to flow from the hot water supply load side heat exchanger 7 to the receiver 8, 31 is an accumulator, and 32 to
35 is a closing valve. And the above 10 temperature sensors TH1 to TH1
0 are the four-way switching valves SV1 and SV2 and the electromagnetic on-off valves SV3 and 5, respectively, as shown in FIG.
Control circuit 4 that controls the electric expansion valves V1 to V5
0 so that signals can be exchanged. As shown in FIG. 3, the control circuit 40 has 10
Temperature signals from three temperature sensors TH1 to TH10 are selectively received via the multiplexer 41, and each cooling and heating operation command signal, set room temperature signal and actual room temperature signal are received from three indoor units B to D. In addition, the CPU 42 receives the hot water supply operation command signal from the hot water storage tank unit E, and the compressor 1
The type of operation command signal and indoor unit B
A RAM 43 that stores in advance the initial setting values of the valve openings of the four electric expansion valves V1 to V4, which are required to be appropriate according to various operation modes such as the number of operations (number of driver's cabins) of ~D. We are prepared. Then, the CPU 42 controls the compressor 1 on and off in accordance with the cooling or heating operation command signal, the actual room temperature signal, and the hot water supply operation command signal from the three indoor units B to D, and as shown in the table below. , four-way switching valve SV1, SV2, solenoid on-off valve
During cooling operation, SV3 and the four electric expansion valves V1 to V4 are controlled as shown in the first row of the same table to reduce the heat on the air conditioning load side of the indoor unit that issues the operation mode signal (hereinafter simply referred to as the operation side). The amount of heat absorbed from the room by the exchangers 3 to 5 is radiated to the outside by the heat source side heat exchanger 2 to cool the corresponding room, while each air conditioning load side heat exchanger 3 to 5, which acts as the evaporator, The degree of superheating of the refrigerant, that is, the difference in refrigerant temperature (T ₃ −
T ₁ ), (T ₄ −T ₁ ), and (T ₅ −T ₁ ) are adjusted to the set superheat degree (SH ₀₁ ) using the corresponding electric expansion valves V1 to V3, while the two stages in the same table are used during cooling hot water supply operation. Control the operation side air conditioning load side heat exchanger 3~
The amount of heat absorbed from the room in step 5 is radiated to the stored water in the hot water storage tank 6 by the hot water supply load side heat exchanger 7, thereby heating the stored water (supplying hot water) and cooling the corresponding room, and at the same time acting as the above-mentioned evaporator. Air conditioning load side heat exchanger 3
The degree of superheating of the refrigerant at 5 to 5, that is, the difference in refrigerant temperature (T ₃ - T ₁ ), (T ₄ - T ₁ ), (T ₅ - T ₁ ), is determined by the corresponding electric expansion valve V1 in the same manner as above. ~ V3 to adjust to the set superheat degree (SH ₀₂ ), and during hot water supply operation, control is performed as shown in the third row of the same table, and the amount of heat absorbed from the outside by the heat source side heat exchanger 2 is transferred to the hot water supply load side heat exchanger 7. While supplying hot water by radiating heat to the water stored in the hot water storage tank 6, the degree of superheating of the refrigerant in the heat source side heat exchanger 2 acting as the evaporator, that is, the difference in refrigerant temperature (T ₉ - T ₁ ), is electrically expanded. Adjust to the set superheat degree (SH ₀₃ ) with valve V4,
Furthermore, during heating operation, the heat exchanger 2 on the heat source side absorbs heat from the outside by controlling it as shown in the fourth row of the same table, and radiates heat into the room through the air conditioning load side heat exchangers 3 to 5 on the operation side, thereby heating the corresponding indoor room. The degree of superheating of the refrigerant in the heat source side heat exchanger 2 that acts as the evaporator while heating the room,
That is, the air conditioning load side heat exchanger 3~ which adjusts the temperature difference ( _T9 - _T1 ) of the refrigerant temperature to the set superheat degree ( _SH04 ) with the electric expansion valve V4 and acts as the above-mentioned condenser.
The degree of subcooling of the refrigerant at step 5, that is, the temperature difference (T ₂ - _{T 6} ), (T ₂ - _{T 7} ), and (T ₂ - T ₈ ) of the refrigerant, is set with the corresponding electric expansion valves V1 to V3, respectively. Adjust to supercooling degree (SC ₀₁ ). In addition, when the operation is stopped during heating,
This is done by stopping each indoor fan 3a, 4a, 5a provided in each indoor unit B, C, D. In this case, the air conditioning load side heat exchangers 3, 4, 5 on the stop side
Since the amount of heat dissipated in is extremely small, the electric expansion valve V
1 to V3 are not fully closed, but are adjusted to the set supercooling degree (SC ₀₂ ) during heating operation, while controlling the loss of heating capacity to an extent that does not pose a practical problem.
This also prevents liquid accumulation as much as possible. Furthermore, the third
In the figure, 45 to 49 each represent five electric expansion valves V.
Driver that drives 1 to V5, 50 is CPU42
A multiplexer that distributes drive pulses (described later) as valve opening control signals for the five electric expansion valves V1 to V5 generated in the 5 electric expansion valves V1 to V5 to the corresponding ones, 51 is a gas shortage indicator that lights up when the refrigerant flow is insufficient, 52 is a power source It's a plug. Further, the electric expansion valve V5 is opened when the operation of the refrigerator is stopped and acts as a pressure equalization expansion valve that balances the pressure between the high pressure side and the low pressure side of the compressor 1.

[Table] Next, the valve opening control of the four electric expansion valves V1 to V4 by the CPU 42 will be explained based on the flowchart of FIG. In addition, during heating operation, 4
Since all of the electric expansion valves V1 to V4 are controlled in valve opening degree as shown in the table above, and the entire control of this embodiment can be explained, the flow during the heating operation will be explained below.
This flowchart starts when a heating operation command signal is received from at least one of the three indoor units, and first, in step _S1 , the heating operation command signal is received from at least one of the three indoor units B to D. After determining the operation mode based on the command signal and the number of command signals received, in step _S2 , a drive pulse as a valve opening control signal is generated in the direction of closing the openings of the four electric expansion valves V1 to V4. The valve closing degree of each of the electric expansion valves V1 to V4 is positioned at an opening degree reference position where the electric expansion valves V1 to V4 are in a fully open state. Then, in step _S3 , the initial setting value of the valve opening of each electric expansion valve V1 to V4 is read from the RAM 43 according to the determined operation mode, and the opening difference between the initial setting value and the opening reference position is determined. A drive pulse of the number of pulses corresponding to the number of pulses is outputted to the corresponding electric expansion valves V1 to V4 to control the valve openings to the respective initial setting values.
Then, in step _S4 , an instruction is given to maintain this valve opening for a predetermined period of time (for example, 5 minutes) corresponding to the transient time until operation stabilizes, and then, in step _S5 , the compressor 1 is started for the first time. . Then, in step _S6 , 10 temperature sensors
After reading the temperatures (T ₁ ) to (T 10 ) at 10 locations in FIG. 2 based on the temperature signals from TH1 to _TH10 , in step _S7 , the refrigerant gas discharge temperature (T ₁₀ ) of the compressor 1 is determined to be abnormal. The magnitude is compared with a predetermined value (T _EM ) corresponding to the rising time, and if the abnormal operation is YES, which is larger than the predetermined value (T _EM ), the set superheat degree (SH ₀₄ ) corresponding to the operation mode is lowered in step _S8 . _The refrigerant gas discharge temperature (T ₁₀ ) is lowered and the process proceeds to step _S9 after waiting _a predetermined time for this state to stabilize. In the case of normal operation, the process immediately proceeds to step _S9 . Then, in step _S9 , the actual degree of superheating (SH) of the refrigerant in the heat source side heat exchanger 2 acting as an evaporator is calculated based on the above temperature difference ( _T9 - _T1 ), and the The actual degree of supercooling (SC) in the air conditioning load side heat exchanger on the operating side and the air conditioning load side heat exchangers 3 to 5 on the stopping side acting as the above temperature difference (T ₂ - T ₆ ), ( T ₂ −T ₇ ), (T ₂ −T ₈ )
In step S ₁₀ , the actual superheat degree (SH) and actual subcooling degree (SC) are calculated based on the corresponding set superheat degree (SH ₀₄ ).
and the set supercooling degree (SC ₀₁ to ₀₂ ). And each is not matched together NO
In this case, the process proceeds to step S ₁₁ , and in step S ₁₁ , if the actual degree of superheating (SH) is larger than the corresponding set degree of superheat (SH ₀₄ ) and the actual degree of supercooling (SC) is greater than the set degree of supercooling. (SC ₀₁ to ₀₂ ), it is determined that the refrigerant flow rate is low, and a drive pulse is output as an opening signal to increase the number of pulses to the corresponding electric expansion valves V1 to V4 to open the valves. On the other hand, if the actual superheating degree (SH) is smaller than the corresponding set superheating degree (SH ₀₄ ) and the actual subcooling degree (SC) is smaller than the set supercooling degree (SC ₀₁ ~ ₀₂ ) If it is smaller than , it is determined that the refrigerant flow rate is large and the corresponding electric expansion valve V1 is activated.
~After outputting a drive pulse as a closing signal to reduce the number of pulses for V4 and reducing the valve opening,
Proceed to step _S12 . On the other _hand , if the actual degree of superheating (SH) and the actual degree of subcooling (SC) are equal to the corresponding set values ( _SH04 ) and ( _SC01 ~ ₀₂ ), respectively, in step S10, the refrigerant flow rate is If it is determined to be appropriate, immediately proceed to step _S12 . Next, in step _S12 , the valve opening degree of electric expansion valve V4, which is in the process of controlling the degree of superheating, is determined, and if NO, which is not fully open, it is determined that the degree of superheating is being controlled appropriately, and the process returns to step _S6 . On the other hand, if the valve opening is fully open (YES), it is determined that there is a refrigerant gas shortage (gas shortage) with a significantly high degree of superheating, and the process proceeds to step _S13 . Since the heating operation is in progress, first, in step _S15 , the indoor units B to D on the heating stop side are checked to determine whether there is a gas shortage due to liquid accumulation in the indoor units B to D on the heating stop side. The set supercooling degree (SC ₀₂ ) is lowered, and the corresponding electric expansion valves V1 to V3 are opened an extra predetermined opening degree to begin recovering the accumulated refrigerant. Then, after waiting a sufficient time for recovery, the valve opening degree of the electric expansion valve V4 that controls the corresponding degree of superheating (SH ₀₄ ) is determined again in step _S16 , and if NO is not fully open, the degree of overheating is determined. It is determined that the compressor 1 has returned to proper control, and returns to step _S6 . On the other hand, if the answer is YES, indicating that the compressor is still fully open, it is determined that the compressor 1 is out of gas, and the operation of the compressor 1 is stopped in step _S14 . The indicator light 51 is turned on. On the other hand, in the case of cooling operation, the operation of the compressor 1 is immediately stopped in step _S14 , and
The out-of-gas indicator light 51 is turned on. When a new heating operation command signal is received from the indoor units B to D on the stopped side, the flowchart shown in FIG. 4 is interrupted and the process proceeds to the flowchart shown in _FIG . After determining the type and calculating the number of driver's cabins in step _S18 to determine the operation mode, in step _S19 the initial setting value of the valve opening degree corresponding to the determined operation mode is read from the RAM 43 and a new value is determined. The valve opening degrees of the electric expansion valves V1 to V3 corresponding to the air conditioning load side heat exchangers 3 to 5 whose operation is to be started are initialized to the above-mentioned initial setting values. Thereafter, an instruction is given to maintain this valve opening degree for a predetermined period of time until the refrigerant flow becomes stable, and the process returns to step _S6 in FIG. Then, at the start of the next operation, the electric expansion valve V1
~ Initial setting of V4 valve opening is performed by following the steps in Figure 6.
This is performed based on the valve opening degree at the time of the previous stable operation, which is updated and stored at the time of the previous stop of the operation, as shown in _S'3 . Therefore, step S ₉ of the flowchart in Figure 4
During heating operation, the degree of superheating (SH) of the refrigerant after passing through the heat source side heat exchanger 2, which acts as an evaporator, is detected based on the temperature difference (T ₉ - T ₁ ), and
an air conditioning load side heat exchanger 3 that acts as a condenser;
Detection in which the degree of subcooling (SC) of the refrigerant after passing through 4 and 5 is detected based on the temperature differences (T ₂ - _{T 6} ), (T ₂ - T ₇ ), and (T ₂ - _{T 8} ), respectively. It constitutes means 55. Also, steps S ₁₀ and S ₁₁ in FIG.
According to
The temperature difference (T ₉ − _{T 1} ) between the above refrigerant temperatures is adjusted so that the actual degree of subcooling (SC) at is equal to the set degree of superheat (SH ₀₄ ) and the set degree of subcooling (SC ₀₁ ), respectively.
A control means 56 is configured to control the valve opening degrees of the corresponding electric expansion valves V1 to V4 according to (T ₂ - T ₆ ), (T ₂ - T ₇ ), and (T ₂ - _{T 8} ). are doing.
Furthermore, when the CPU 42 receives an operation command signal from at least one of the three indoor units B to D, the flowchart shown in FIG. 4 starts, thereby detecting when the refrigerator starts operating. The start-of-operation detecting means 57 is configured, and when the refrigerator starts operating, that is, when the flowchart in FIG. 4 starts, step _S1 is executed.
It constitutes an operation mode determining means 58 which proceeds to the step 1 and determines the operation mode of the refrigerator. Further, a storage means 5 is configured to store in advance the initial setting values of the electric expansion valves V1 to V4 according to various operating modes of the refrigerator using the RAM 43 of the control circuit 40.
9. In addition, proceed to step _S3 after step _S1 in the flowchart of FIG.
In other words, it constitutes a readout means 60 that receives a signal from the operation mode determination means 58 and reads out the initial set value corresponding to the operation mode from the RAM 43 (storage means 59) in a step before step _S3 . ₃ After the processing operation in the first stage, the process proceeds to the next stage, and when the refrigerator starts operating, the valve openings of the electric expansion valves V1 to V4 correspond to the operation mode read out in step _S3 (reading means 60). The initial setting means 61 is configured to set the initial setting value to the initial setting value. Furthermore, according to the control flow shown in Figure 6, RAM4
3 (storage means 59) is rewritten each time the refrigerator is operated, to the valve opening degree when the operation is stable. Therefore, in the above embodiment, when the refrigerator starts operating, the stepping motor type electric expansion valves V1 to V4, whose degree of superheating or degree of subcooling is to be controlled, have their opening degrees stored in the RAM 43 (memory means 59). The initial setting value corresponding to the operation mode read from Since the initial set opening value is used, even if the valve opening of the electric expansion valve is initially far away from the appropriate valve opening at stable operation, the operating mode will be adjusted at the start of operation. The valve opening is positioned close to the appropriate valve opening during stable operation, and as the operation is repeated, the opening is gradually positioned to be approximately equal to the optimum valve opening. As a result, the valve opening of the electric expansion valve always converges and stabilizes to the appropriate valve opening in a short time regardless of the operation mode, which effectively improves the convergence stability of the valve opening and, in turn, improves refrigeration. It is possible to significantly stabilize the ability at an early stage. In the above embodiment, when the refrigerator starts operating, the electric expansion valves V1 to
Although V4 was once positioned at the opening reference position where the valve opening is fully closed, it is of course possible to position it at the opening reference position where the valve opening is fully open. It is not always necessary to control both the degree of superheating and the degree of subcooling, and only one of them may be used. Furthermore, in the above embodiment, when the electric expansion valve V4 under control is fully open during heating operation, the electric expansion valves V1 to V3 corresponding to the indoor units B to D on the stop side are set to the supercooling degree (SC ₀₂ ). In addition, the electric expansion valves V1 to V corresponding to the indoor units B to D on the stop side are
3 may be forcibly fully opened for a predetermined period of time to recover the accumulated refrigerant.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of the present invention, Figure 2 is a block diagram showing the configuration of the present invention.
6 to 6 show embodiments of the present invention, FIG. 2 is a refrigerant piping system diagram when applied to an air-conditioning/heating water heater, FIG. 3 is an electric circuit diagram showing the internal configuration of the control circuit, and FIGS. FIG. 5 is a flowchart showing the operation of the CPU, and FIG. 6 is a flowchart showing a modified example of the operation of the CPU. V1-V4...Electric expansion valve, 2-5...Heat exchanger, 43...RAM, 55...Detection means, 56...
...control means, 57...operation start detection means, 58
...Operation mode determination means, 59...Storage means, 6
0... Reading means, 61... Initial setting means, 6
2... Rewriting means.

Claims (1)

[Claims] 1 Electric expansion valves V1 to V4 whose opening degree can be adjusted; a detection means 55 for detecting the degree of superheating or subcooling of the refrigerant after passing through the heat exchangers 2 to 5; control means 56 for controlling the valve opening degrees of the electric expansion valves V1 to V4 according to the degree of superheating or subcooling of the refrigerant in the heat exchangers 2 to 5, and In the refrigerator which is held at a certain value, operation start time detection means 57 detects when the operation of the refrigerator starts, and operation mode determination means 58 determines the operation mode of the refrigerator.
The electric expansion valve V1 according to the operating mode of the refrigerator
~ Storage means 59 for storing the initial setting value of V4 in advance
and receiving the signal from the driving mode determining means 58,
The storage means 5 stores the initial setting values according to the operation mode.
9; and initial setting means 61 that receives the signal from the start-of-operation detection means 57 and positions the valve opening degrees of the electric expansion valves V1 to V4 to the initial setting values read by the reading means 60. and a rewriting means 62 for rewriting each initial setting value stored in the storage means 59 to the valve opening degree when the operation is stable each time the refrigerator is operated. refrigerator.