JPH0566501B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heat pump device in which an electric refrigerant flow control valve that controls the refrigerant flow rate by an electric signal is provided in a liquid refrigerant path forming a refrigeration cycle. It is something.

[Prior Art] A compressor that sucks in refrigerant gas, compresses it, and discharges it, a four-way valve that switches the refrigerant circulation direction, a user-side heat exchanger that uses a fluid that has undergone heat exchange with the refrigerant,
A refrigeration cycle is formed by a heat exchanger on the non-use side, etc., which exchanges heat between the refrigerant and a fluid that is not particularly used, and a single device can cool and heat the fluid on the use side. In heat pump devices, which can be used with arbitrary switching, energy saving and improved reliability are pursued, and in place of the mechanical expansion valves and capillary tubes traditionally used as refrigerant flow control means, precise electrical signals are now being used. Electric refrigerant flow control valves, which enable efficient control, have come into use.

FIG. 4 is an overall configuration diagram of a conventional heat pump device that controls the flow rate of refrigerant using such an electric flow control valve. In the figure, 1 is a compressor that sucks in, compresses, and discharges refrigerant gas; 1 is a switching valve also called a four-way valve that switches the flow path of the refrigerant gas discharged from the compressor 1, and 3 is a user-side heat exchanger (hereinafter simply referred to as a four-way valve) that exchanges heat between the refrigerant gas delivered from the compressor 1 and the user-side fluid. 4 is a non-use side heat exchanger (hereinafter simply called a heat exchanger) that exchanges heat between the refrigerant gas sent from the compressor 1 and a non-use fluid such as outdoor air. ), 5 is heat exchanger 3 and 4
5a is an electric refrigerant flow control valve (hereinafter simply referred to as flow control valve) that is installed in the refrigerant path connecting the refrigerant and adjusts the refrigerant flow rate so as to change high-pressure refrigerant to low-pressure refrigerant. an electromagnetic coil that determines the temperature; 6 is an accumulator that separates liquid refrigerant and gas refrigerant and causes only the gas refrigerant to be sucked into the compressor 1;
7 is a fan for feeding the unused fluid to the heat exchanger 4; 21, 22, and 23 are a refrigerant temperature detection device on the usage side, a refrigerant temperature detection device on the unused side, and a suction refrigerant temperature detection device, which are closely fixed to the refrigerant pipes, respectively. A device (hereinafter referred to simply as a temperature detection device), 24 controls the output value of the flow rate control valve 5, that is, the refrigerant, so that the temperature difference is maintained within a certain range based on the detected temperatures of the temperature detection devices 21, 22, and 23. Control valve drive output value calculation means 25 calculates the flow rate, and 25 supplies a current corresponding to the control valve output value to the electromagnetic coil 5a of the flow rate control valve 5 based on the calculation result of the control valve drive output value calculation means 24.
This is a control valve drive output means that adjusts the valve opening degree by controlling the flow. Note that the solid arrows of the refrigerant feeding path indicate the refrigerant circulation direction during the heating operation to heat the user-side fluid, and the dotted line arrows indicate the refrigerant circulation direction during the cooling operation to cool the user-side fluid.

With the above configuration, during heating operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is supplied to the heat exchanger 3 via the switching valve 2, and radiates heat to the user-side fluid to heat it and liquefy at the same time. This liquefied refrigerant is depressurized by the flow control valve 5 to become a low-temperature, low-pressure gas-liquid mixed refrigerant, and then flows into the heat exchanger 4 where it absorbs heat from the unused fluid supplied by the fan 7. Vaporize. The gas refrigerant vaporized in this way flows into the accumulator 6 via the switching valve 2, and the remaining liquid refrigerant that has not been completely vaporized in the heat exchanger 4 is separated here, and only the low-pressure gas refrigerant is transferred to the compressor 6.
is inhaled.

In addition, when the temperature of the air as the non-use side fluid is low during heating operation, moisture in the air adheres to the heat exchanger 4 in the form of frost, and when the amount of frost increases, the predetermined heat exchange performance cannot be obtained. It disappears. Therefore, the frost is removed by switching the switching valve 2 for a short time. So-called defrosting operation is performed. During this defrosting operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is supplied to the heat exchanger 4 via the switching valve 2, and is liquefied at the same time as defrosting by dissipating heat to the frost attached thereto. Hereinafter, the refrigerant passes through the flow control valve 5 (at this time, the opening degree of the flow control valve is fully open) in the opposite direction to the above-mentioned path, and then flows into the heat exchanger 3, absorbing heat from the user-side fluid. and vaporize. Further, the vaporized gas refrigerant flows into the accumulator 6 via the switching valve 2 and is then sucked into the compressor 1.

On the other hand, during the cooling operation, the high temperature and high pressure refrigerant gas discharged from the compressor 1 is liquefied in the heat exchanger 4, is depressurized by the flow control valve 5, and is then heat exchanged, just as in the defrosting operation described above. The fluid is cooled and vaporized at the same time by absorbing heat from the usage fluid in the container 3, and returns to the compressor 1 via the switching valve 2 and the accumulator 6.

As described above, in a heat pump device that switches between heating operation and cooling operation as necessary,
Even when the usage side fluid temperature and the non-use side fluid temperature change, it is necessary to adjust the refrigerant flow rate by adjusting the valve opening degree of the flow rate control valve 5 so that the refrigerant returning to the compressor 1 is reliably vaporized.

For this reason, for example, during heating operation, the temperature of the low-pressure gas-liquid mixed refrigerant that has passed through the flow control valve 5 is detected by the temperature detection device 22, while the temperature of the gas refrigerant flowing out from the heat exchanger 4 is detected by the temperature detection device 23. death,
The control valve drive output calculation means 24 calculates an output value that can suppress the detected temperature difference within a certain range, and the control valve drive output means 25 changes the current flowing through the electromagnetic coil 5a so that the detected temperature difference is within a certain range, and opens the valve. I was adjusting the level.

This means that the refrigerant that has passed through the flow rate control valve 5 is a low-temperature, low-pressure gas-liquid mixed refrigerant, and is in a complete two-phase state, so the refrigerant temperature has reached the saturation temperature of the refrigerant pressure. Further, the refrigerant flowing into the heat exchanger 4 gradually vaporizes and reaches the outlet of the heat exchanger 4 with a pressure drop. Therefore, by assuming the pressure loss of the heat exchanger 4 and detecting the refrigerant temperature with the temperature detection device 23, the amount of superheating of the refrigerant gas at the outlet of the heat exchanger 4 can be determined.
If the temperature difference obtained by the temperature detection devices 22 and 23 is controlled within a certain range, only the low-pressure gas refrigerant having a predetermined amount of superheat can be drawn into the compressor 1.

On the other hand, during cooling operation, the heat exchanger 3 serves as a low-pressure side evaporator, so the refrigerant is heated so that the deviation between the temperature detected by the temperature detection device 21 and the temperature detected by the temperature detector 23 is kept within a certain range. Flow rate is controlled.

[Problems to be Solved by the Invention] In the conventional heat pump device described above, the amount of superheating of the suction gas refrigerant to the compressor 1 is controlled based on the refrigerant temperature detection value of each part. When the user-side fluid temperature is low, the high pressure becomes low and the temperature detected by the temperature detection device 22 decreases, making the valve opening of the flow rate control valve 5 smaller than necessary. As a result, there was a problem in that the capacity of the compressor 1 was significantly reduced.

In addition, since the amount of superheating of the suction gas refrigerant to the compressor 1 is controlled, the temperature of the fluid on the user side increases,
On the other hand, in high compression ratio operation under conditions where the temperature of the unused fluid has decreased, the temperature of the gas refrigerant discharged from the compressor 1 will rise abnormally, resulting in poor lubrication due to carbonization of the lubricating oil in the compressor 1. There have been problems in that the compressor's life and reliability may be reduced due to overheating of the compressor drive motor.

Furthermore, when the valve opening degree of the flow rate control valve 5 is adjusted according to the detected temperature of the gas refrigerant sucked into the compressor 1, the change in the flow rate of the refrigerant due to the adjustment of the valve opening degree brings about a change in the temperature of the gas refrigerant again. Therefore, there was a problem that the operation was difficult to stabilize, and the flow rate control valve 5 frequently opened and closed.

This invention was made to solve these problems, and it is possible to maintain a good operating condition of the compressor even when the temperature of the fluid on the user side and the fluid on the non-user side fluctuates, and there is no need for a flow control valve. The purpose of the present invention is to provide a heat pump device that can prevent frequent opening and closing operations, thereby improving the reliability and extending the life of the entire device.

[Means for Solving the Problems] A heat pump device according to the present invention includes a first heat exchanger that forms a refrigeration cycle together with a compressor and exchanges heat between a refrigerant and a fluid on a user side, and a first heat exchanger that exchanges heat between a refrigerant and a fluid on a non-user side. A first temperature detection device that detects the temperature of the refrigerant discharged from the compressor in a heat pump device in which a flow rate control valve that controls the flow rate of liquid refrigerant is provided in a path connecting the second heat exchanger that exchanges heat therebetween. a second temperature detection device that detects the temperature of the fluid on the usage side; a third temperature detection device that detects the temperature of the fluid on the non-use side; and temperatures detected by the second and third temperature detection devices. a first calculating means for simultaneously calculating a control valve drive output reference value and a discharge refrigerant reference temperature of the compressor for setting the flow rate control valve to a reference opening degree, and the second and third temperature detection means; When the detected temperature of each device is within a preset temperature range, a control valve drive output correction value is calculated based on the difference between the detected temperature of the first temperature detection device and the discharge refrigerant reference temperature of the compressor, and the control valve drive output correction value is calculated. and second calculation means for correcting the control valve drive output reference value, and controls the opening degree of the flow rate control valve based on the corrected control valve drive output reference value.

[Function] The heat pump device according to the present invention can operate even when the temperature of the fluid on the user side and the non-user side changes.
The operating condition of the compressor can be maintained in good condition, and the flow control valve can be prevented from opening and closing unnecessarily frequently.

Further, the second calculation means corrects the control valve drive output reference value based on the discharge refrigerant temperature of the compressor detected by the first temperature detection device.
This prevents abnormal overheating of the refrigerant temperature discharged from the compressor even under a wide range of changes in temperature conditions.

Furthermore, since the second calculation means corrects the control valve drive output reference value only when the temperature of the fluid on the user side and the fluid on the non-user side is within a preset temperature range, there is no need to set a temperature range. Compared to correction, the number of opening and closing operations of the flow control valve can be significantly reduced.

[Embodiment] Fig. 1 is an overall configuration diagram of an embodiment of the present invention, in which numerals 1 to 7 are exactly the same as the conventional device shown in Fig. 4, and 11, 12, 1
3 is a utilization side fluid temperature detection device, an unused side fluid temperature detection device, a compressor discharge refrigerant temperature detection device (hereinafter simply referred to as temperature detection device), and 14 is based on the detected temperature of temperature detection devices 11 and 12, Control valve drive output reference value calculation means for calculating the drive output reference value of the flow control valve 5; 15 is a temperature detection device 1;
Control valve drive output correction value calculation means 16 calculates a drive output correction value of the flow control valve 5 based on the detected temperatures of 1, 12, and 13; 16 is a control valve drive output reference value calculation means 14 and a control valve drive output correction value Arithmetic means 1
5 is a control valve drive output means that controls the valve opening degree of the flow rate control valve 5 by causing a current to flow through the electromagnetic coil 5a such that the drive output value calculated by 5 is obtained.

Here, the flow control valve 5 operates the control valve opening in the closing direction when the reference value determined by the control valve drive output reference value calculation means 14 changes to a large value, and operates the control valve opening in the closing direction when the reference value changes to a small value. The opening degree operates in the opening direction, and when the reference value is zero, the control valve opening degree operates so as to be fully open.

FIG. 2 is a circuit diagram showing the detailed configuration of the main parts of the embodiment shown in FIG.
1, memory 32, input circuit 33 and output circuit 3
4, an A/D converter 35 that converts the temperature detection value input as an analog quantity into a digital quantity and applies it to the input circuit 33;
3 is a pulse generator that applies a pulse signal of the number of pulses corresponding to the output of the output circuit 34 to the electromagnetic coil 5a;
7 is an operation switch for the heat pump device, 38 is a changeover switch for switching the heat pump device between cooling operation and heating operation, and 41, 42, and 43 are resistors connected to the power source in series with the temperature detection devices 11, 12, and 13, respectively. , 44 and 45 are resistors connected in series with the operation switch 37 and the changeover switch 38, respectively, and connected to a power source, and 46 is the main body of the control device.

The operation of the refrigeration cycle of the heat pump device configured as described above is the same as that of the conventional device, so a description thereof will be omitted, and the control operation of the flow rate control valve 5 will be mainly explained with reference to the flowchart in FIG. This will be explained below. Note that the flowchart in Figure 3 is based on the second flowchart.
Memory 32 of the microcomputer 30 shown in the figure
This shows the portion of the program stored in the program that controls the flow rate control valve 5.

First, when the operation switch 37 is turned on, a signal indicating the state of the changeover switch 38 is input to the input circuit 33 and the operation of the compressor 1 is started.
The program is executed from step 50 in the figure. In step 50, the time is counted from the start of operation, and 30
Each time the second elapses, the process proceeds to step 51; otherwise, the process proceeds to step 54. this house,
In step 51, the utilization side fluid temperature Tw and the non-utilization side fluid temperature Ta obtained by the temperature detection devices 11 and 12, respectively, are read. And step 52,
53, the control drive output reference value Qis of the flow control valve 5 is determined based on the read fluid temperatures Tw and Ta.
and calculate the compressor discharge refrigerant reference temperature Tds.
On the other hand, in step 54, it is determined whether or not the defrosting operation is in progress. If the defrosting operation is in progress, the process proceeds to step 64, and if the defrosting operation is not in progress, the process proceeds to step 55.

Next, in step 55, it is determined whether the fluid temperature Tw on the user side and the fluid temperature Ta on the non-user side are within the preset range.
It is determined, and if it is within the set range, the process proceeds to step 56. In step 56, time is counted from the start of operation, and it is determined whether or not the time is in 4-minute increments, and the process in step 57 is performed every time in 4-minute increments. In this step 57, the compressor discharge refrigerant device Td detected by the temperature detection device 13 is read, and in step 58, this compressor discharge refrigerant temperature Td and the above step are read.
53, and when Td>Tds+A, that is, the reference temperature
If the actual temperature Td is higher than Tds by A° C. or more, the process proceeds to step 59, where the control valve driving output correction value Qic of the flow rate control valve 5 is decreased by C.
Here, if the relationship is Td<Tds+A, proceed to step 60, and check whether or not the compressor discharge refrigerant reference temperature Tds is lower by B°C, that is, Td<
When Tds-B, the process proceeds to step 61, where the control valve drive output correction value Qic is increased by C, and the process proceeds to step 62. Also, the compressor discharge refrigerant temperature Td is (Tds−
B) and (Tds+A), the process of step 60 is not executed and the control valve drive output correction value Qic does not change. And step 62
In step 63, the control valve drive output reference value Qis obtained in step 52 and the control valve drive output correction value Qic stored in step 62 are added to determine the control valve drive output value Qi. At 66, this control valve drive output value Qi is added to the output circuit 34 shown in FIG. Note that if the fluid temperature Tw on the user side and the fluid temperature Ta on the non-user side are outside the preset range in step 55, the process proceeds to step 62, so the compressor discharge refrigerant temperature Td is
The control valve drive output correction value Qic does not change.
This means that when the user fluid temperature Tw is not so high during heating operation, the high pressure is low and the compressor discharge refrigerant temperature Td does not become high, so there is no need to add the control valve drive correction value Qic. are doing.

On the other hand, if it is determined in step 54 that the defrosting operation is in progress, the process proceeds to step 64, where the timer count is reset, and the control valve drive output value Qi is set to a constant value D in step 65. During defrosting operation, the fluid temperature on the user side
For example, the defrosting time is shortened by setting the valve opening of the flow rate control valve 5 to be maximum, regardless of Tw and the unused fluid temperature Ta. Furthermore, since the processes in steps 55 to 63 are not executed during defrosting operation, the control valve drive output correction value Qic is not rewritten by reading the unstable compressor discharge refrigerant temperature Td during defrosting. Further, for 4 minutes after the end of defrosting, the judgment at step 56 does not proceed to the processing at step 57, thereby avoiding rewriting of the control valve drive output correction value Qic during unstable operation after the end of defrosting.

By the way, the function of step 56 not only prevents erroneous correction in the unstable operation range after the end of defrosting, but also prevents correction in the unstable operation range immediately after the start of operation. Furthermore, while the control valve drive output reference value Qic is rewritten every 30 seconds, the control valve drive output correction value Qic based on the compressor discharge refrigerant temperature Td is rewritten every 4 minutes because the flow rate control valve This is to prevent unnecessary opening/closing operations as shown in step 5. That is, since the compressor discharge refrigerant temperature Td changes with a considerable time delay in response to a change in the flow rate control valve 5, the correction interval is lengthened in consideration of this delay time, thereby making it possible to perform frequent correction operations. At the same time, we aim to reach a stable operating state in a short period of time.

Note that the calculation cycle of the control valve drive output reference value Qis and the calculation cycle of the control valve drive output correction value Qic are not limited to the above-mentioned 30 seconds and 4 minutes, respectively, but can be determined appropriately according to the heating and cooling loads. However, by setting the latter cycle much larger than the former, it is possible to prevent the flow rate control valve from opening and closing unnecessarily frequently.

[Effects of the Invention] As described above, according to the present invention, the first heat exchanger forms a refrigeration cycle together with the compressor and exchanges heat between the refrigerant and the fluid on the utilization side, and the first heat exchanger that exchanges heat between the refrigerant and the fluid on the non-utilization side. In the heat pump device, a flow rate control valve for controlling the flow rate of liquid refrigerant is provided in a path connecting the second heat exchanger with which the heat exchanger exchanges heat. , a second temperature detection device that detects the temperature of the fluid on the utilization side, a third temperature detection device that detects the temperature of the fluid on the non-utilization side, and a temperature detected by the second and third temperature detection devices; a first calculation means for simultaneously calculating a control valve drive output reference value and a discharge refrigerant reference temperature of the compressor for setting the flow rate control valve to a reference opening degree based on the first calculation means; and the second and third temperature detection devices. When the detected temperatures of the first temperature detection device and the discharge refrigerant reference temperature of the compressor are within respective preset temperature ranges, a control valve drive output correction value is calculated based on the difference between the temperature detected by the first temperature detection device and the reference temperature of the refrigerant discharged from the compressor. and a second calculation means for correcting the valve drive output reference value, and the opening degree of the flow rate control valve is controlled by the corrected control valve drive output reference value.
To enable accurate correction, to maintain a good operating condition of the compressor even when the temperature of the fluid on the user side and the non-user side fluctuates, and to prevent the flow control valve from opening and closing unnecessarily frequently. I can do it.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of an embodiment of the present invention, Fig. 2 is a circuit diagram showing the detailed configuration of the main part of the embodiment, and Fig. 3 is a flowchart for explaining the operation of the embodiment. , FIG. 4 is an overall configuration diagram of a conventional heat pump device. In the figure, 1 is a compressor, 2 is a switching valve, 3 is a heat exchanger on the use side, 4 is a heat exchanger on the non-use side, 5 is an electric flow control valve, 5a is an electromagnetic coil, 6 is an accumulator, and 11 is a use side heat exchanger. 12 is a side fluid temperature detection device, 13 is a discharge refrigerant temperature detection device. In each part, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1 A first heat exchanger that forms a refrigeration cycle with the compressor and exchanges heat between the refrigerant and the fluid on the user side, and a second heat exchanger that exchanges heat between the refrigerant and the fluid on the non-user side.
In the heat pump device, a flow control valve for controlling the flow rate of liquid refrigerant is provided in a path connecting the heat exchanger to the heat exchanger.
a second temperature detection device for detecting the temperature of the fluid on the usage side, a third temperature detection device for detecting the temperature of the fluid on the non-utilization side, and a second temperature detection device for detecting the temperature of the fluid on the non-utilization side;
and based on the detected temperature of the third temperature detection device,
a first calculation means for simultaneously calculating a control valve drive output reference value for setting the flow control valve to a reference opening degree and a discharge refrigerant reference temperature of the compressor; and detection by the second and third temperature detection devices. When the temperature is within a preset temperature range, a control valve drive output correction value is calculated based on the difference between the temperature detected by the first temperature detection device and the reference temperature of the refrigerant discharged from the compressor, and the control valve is driven. a second calculation means for correcting an output reference value, and controlling the opening degree of the flow rate control valve based on the corrected control valve drive output reference value.