JP2000297771A - Noise reduction method of scroll compressor and control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a heat pump. SOLUTION: A scroll type compressor 12 is sued for a heat pump system 10 having a four-way selector valve 20 driven by a solenoid 21. A processor 25 watches a system parameter showing whether the reverse turn of a flow was occured or is going to occur and at the detection time, the motor 13 of the compressor 12 is stopped for a prescribed time. Thus, in this term, an uncomfortable noise generated by the separation of a scroll element caused by the low pressure difference over the compressor 12 is prevented. When this term is finished, the motor 13 of the compressor 12 is re-started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump, and more particularly to a heat pump system using a scroll compressor.

[0002]

BACKGROUND OF THE INVENTION The use of scroll compressors is well known and has become widespread in the industry due to the many advantages offered by this type of compressor. Scroll compressors work well in heat pump systems, but can generate noise when the operating mode of the system changes. This most often occurs when operating in the heating mode and the controller of the system requests a defrost cycle.

[0003] Tests have shown that compressor noise is reduced when the differential pressure between the fixed and orbiting scrolls of the compressor is reduced, thereby causing the scroll elements to separate. This phenomenon occurs for a short time after the four-way switching valve has been switched and the direction of the refrigerant flow through the system has been reversed. It takes 20-30 seconds for the system to stabilize after the reversal occurs, after which it returns to normal, relatively quiet operation.

[0004]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to improve a heat pump.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat pump system using a scroll type compressor, in which a defrost cycle is performed when the flow of refrigerant flowing through the system is reversed, especially when the system is operating in a heating mode. Achieved by preventing noise at times. A processor is programmed to detect when a four-way switching valve of the system has been switched, signifying a reversal of refrigerant flow. The processor analyzes and processes the detected signal and, if it determines that an inversion has occurred just before or is in progress, stops the compressor for a period of time sufficient for the system to stabilize, thereby causing the Prevent unwanted compressor noise from occurring at the beginning of

[0006] The above and other objects of the present invention are:
BRIEF DESCRIPTION OF THE DRAWINGS The invention is better understood from the following detailed description when taken in conjunction with the accompanying drawings.

[0007]

Referring first to FIG. 1, there is shown a heat pump system, generally designated 10, embodying the teachings of the present invention. This system uses a scroll compressor, which sends refrigerant through line 11 to an outdoor heat exchanger or coil 14 when the system is operating in cooling mode. In this mode, the outdoor coil is acting as a condenser, and the condensed refrigerant is sent through a refrigerant line 17 to an indoor heat exchanger or coil 16. An expansion device 1 is installed in the refrigerant pipe.
5 is incorporated, which expands the high pressure refrigerant passing through the piping and reduces the pressure. In the cooling mode, the indoor coil acts as an evaporator and removes heat from the indoor air to provide a cooling effect. The refrigerant vapor generated in the indoor coil is then sent through a pipe 18 to the inlet side of the compressor.

Both the suction side pipe 24 and the discharge side pipe 23 of the compressor are connected to a four-way switching valve 20, and the four-way switching valve is switched by a solenoid actuator 21 when the operation mode of the system is changed. Reverse the flow of the refrigerant flowing through the system. The solenoid actuator is under the control of processor 25, which switches the valve, especially when the system is in heating mode. At this time, the high-pressure refrigerant from the compressor is sent to the indoor coil 16, which in turn acts as a condenser for the system, warming the indoor air. Instead, the outdoor coil acts as an evaporator, extracting heat from the surrounding environment. The expansion device 15 is designed to automatically expand the refrigerant flowing in either direction through the refrigerant pipe.

A thermal sensor 30 is associated with the outdoor coil 14 and supplies temperature data to the processor 25 of the system. When the system is in the heating mode, the processor processes and analyzes the temperature data to determine when to start the defrost cycle. As is well known in the art, during the defrost cycle the system is thermodynamically inverted and the outdoor coils act as condensers, so that the heat exchanger coils are warmed and the frost on the coil surfaces reduces the efficiency of the system. Or the ice melts.

As will be described in more detail below, when the processor determines that a defrost cycle should be initiated,
It is programmed to send an input signal to the solenoid actuator 21. This signal causes the four-way switching valve to switch, reversing the flow of refrigerant through the system.

[0011] As mentioned above, it has been found that reversing the flow through the heat pump causes unpleasant noise in the scroll compressor. The scroll compressor operates by moving a sealed refrigerant pocket 34 from the low pressure region shown in FIG. 2A to the high pressure region shown in FIG. 2D, as shown in FIGS. 2A-2D. The sealed fluid pocket comprises two end plates, a fixed scroll element 40 and an orbiting scroll element 4.
It is separated by one. One end plate 37 supports the fixed scroll element 40 and the other plate (not shown) supports the orbiting scroll element 41. Both scroll elements are arranged on parallel axes, so the sealed pockets confine the refrigerant in a decreasing volume as the orbiting scroll moves in rolling contact with the fixed scroll, as shown. . Although not shown, inlet and outlet ports are provided to allow refrigerant to enter and exit the mobile pocket area.

It has been found that both the orbiting and stationary scroll elements of the compressor separate when the pressure differential across the compressor is low. All scroll compressors cannot escape temporary scroll separation that occurs under low pressure differentials. Experiments have shown that a period of low pressure differential occurs immediately after the four-way switching valve is switched, for example at the beginning or end of a defrost cycle, and lasts for about 20 seconds. During this period, the scroll elements separate due to the unstable flow, producing undesirable noise.

As noted above, processor 25 receives temperature-related data regarding outdoor coil 14 from sensor 30 and processes this information to determine when to start and end the defrost cycle. Have been. To start the defrost cycle when the heat pump system is operating in heating mode,
A signal is sent to a solenoid actuator 21, which switches a four-way valve to reverse the flow of refrigerant through the system. At this time, the outdoor coil operates as a condenser without airflow, and the frost on the coil is melted. When the defrosting process is completed, the processor again sends a signal to the solenoid actuator to switch the four-way switching valve, and the system returns to the normal heating mode again.

[0014] Thus, during each reversal period, at the beginning and end of the defrost cycle, the pressure differential across the compressor is low, producing undesirable noise. The processor is further programmed to stop the compressor motor 13 (see FIG. 1) for a period of time at the beginning and end of each defrost cycle. If the processor determines that a defrost cycle is about to begin or end, it signals the motor switch 27 (see FIG. 1) to stop the compressor motor for about 30 seconds. This 30
At the end of the second pause, the processor again signals the motor switch to restart the compressor motor. By stopping the compressor for a short time at the beginning and end of the defrost cycle,
Unpleasant noise generation during this unstable period is prevented.

Turning now to FIG. 3, there is shown a flow chart illustrating the steps that the processor must follow at the beginning and end of each defrost cycle, or otherwise when the refrigerant flowing through the system is reversed. The processor reads and stores data regarding the voltage of the solenoid actuator to determine whether the system is in a heating mode. In the heating mode, the four-way switching valve is in the first position, and the solenoid actuator has not been activated. Therefore, the voltage applied to the terminals of the solenoid is 0 volt. At the beginning of the defrost cycle, a voltage of, for example, 24 volts is applied to the terminals of the solenoid, and the solenoid is activated and switches the four-way switching valve.

The stored data is stored in the four-way switching valve 20.
To determine if the direction of the refrigerant flow through is reversed. The processor 25 detects the value of the voltage level of the input signal across the input terminal of the solenoid 21 and compares the detected voltage level of the input signal with the voltage level of the input signal in the previous operation mode. For example, when the heat pump system 10 is operating in the heating mode, the voltage level of the input signal to the solenoid 21 is 0 volt. This value is, as shown in block 80,
Stored by the processor 25. Processor 25
Continually monitors the input signal, as indicated by block 82. If the processor 25 detects a change in the voltage level of the input signal as shown in block 84,
Processor 25 samples the input signal for 0.5 seconds to confirm that a change in the input signal voltage level has occurred (see blocks 86 and 88). That is, in this example, processor 25 reads the voltage level of the input signal N times in 0.5 seconds and compares these sampled voltage levels with the stored input signal voltage level, in this case 0 volts. I do. If processor 25 determines that M of the N samples indicate that a change in the voltage level of the input signal has occurred and the current input signal is 24 volts, then processor 25 defrosts. Knowing that a cycle has started or that the mode of operation of the system has changed, the compressor motor 13 is turned on for a predetermined time, usually 30 seconds.
Stop. These steps are performed at blocks 90, 92,
And 94. The above procedure is also used to determine when to stop the compressor motor 13 when returning from the cooling or defrosting mode to the heating mode. The voltage level of the input signal may be different from that described in this embodiment.

After the compressor motor 13 has been turned off for a predetermined period of time, as indicated by block 96, the processor 25 automatically restarts the compressor motor 13 and returns to the circuit. Then processor 25
Resets the 30 second timer as shown in block 98 and stores the new input voltage value in memory as shown in block 80.

It will be apparent to those skilled in the art that other methods may be used to determine when to stop compressor 12. For example, as described above, when the system 10 changes operating modes, there are sudden changes in discharge and suction pressures. Therefore, it is also possible to monitor the pressures on the discharge side and the suction side to determine when to stop the compressor 12. When the discharge pressure changes, the voltage value of the compressor motor 13 also changes. Therefore, the voltage value of the compressor motor 13 can be monitored to determine when to stop the compressor 12. Similarly, appropriate input data from the temperature of the outdoor coil may be provided to the processor to activate and deactivate the compressor motor based thereon.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a heat pump using a scroll compressor embodying the teachings of the present invention.

FIGS. 2A to 2D are explanatory views showing the principle of the compression action, illustrating the fitting relationship of the scroll elements of the compressor used in the system of FIG. 1;

FIG. 3 is a flow chart showing the steps for controlling compressor operation to prevent undesirable compressor noise when the direction of the refrigerant flow through the system is reversed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Heat pump system 11, 17, 18 ... Piping 13 ... Compressor motor 14 ... Outdoor heat exchanger 15 ... Expansion device 16 ... Indoor heat exchanger 20 ... Four-way switching valve 21 ... Solenoid actuator 23 ... Discharge side piping 24 ... Suction side piping 25 ... Processor 27 ... Motor switch 30 ... Heat sensor

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Larry Jay. Berkhart United States of America, Indiana, Indianapolis, Radburn Circle 7508 (72) Inventor Satish Earl. Das United States of America, Indiana, Indianapolis, Normandy Boulevard 7531 (72) Inventor Timothy Jay. Schnell United States of America, Indiana, Clyton, Lakewood Triles 4021

Claims (11)

[Claims] 1. A method for reducing noise of a scroll compressor used in a heat pump system having a four-way switching valve, wherein a change in a direction of a refrigerant flow flowing through the system occurs.
Or a sensing step for sensing a system parameter indicating that a change is about to occur, and whether a change in the direction of refrigerant flow through the system has occurred.
Or a stopping step of stopping the scroll compressor for a predetermined time when it is about to occur, and a method for reducing noise of the scroll compressor. 2. The method according to claim 1, wherein the detecting step includes detecting a change in the position of a four-way switching valve of the system. 3. The method further comprises the step of providing a solenoid actuator for controlling the four-way switching valve,
2. The method of claim 1, wherein said detecting step includes detecting a voltage change across an input terminal of said solenoid actuator. 4. The method further comprising: providing a temperature sensor for monitoring a temperature of an outdoor coil of the system to provide an output signal indicative of the sensed temperature; and wherein the output signal reaches one or more thresholds. Switching the four-way selector valve at times. 5. The method according to claim 1, further comprising the step of restarting the compressor when the predetermined time has elapsed.
Scroll compressor noise reduction method. 6. The method of claim 1, wherein said predetermined time is about 30 seconds. 7. A control system for a scroll compressor used in a heat pump having a four-way switching valve for a refrigerant activated by a solenoid, wherein at least one system parameter is monitored which indicates a change in a direction of a refrigerant flow flowing through the heat pump. A means for stopping the compressor motor for a predetermined time when the processor detects that a change in the system parameter has occurred or is about to occur. Control device for scroll compressor. 8. The scroll compressor control of claim 7, further comprising sensing means for detecting a change in the position of a four-way switching valve of the system and for providing an output signal to said processor indicating a reversal of refrigerant flow through the system. apparatus. 9. The control device for a scroll compressor according to claim 8, wherein said detecting means further includes means for detecting an input voltage across a solenoid actuator of said four-way switching valve. 10. The scroll compressor control device according to claim 9, wherein said processor further includes timer means for restarting said compressor after said predetermined time. 11. The control device for a scroll compressor according to claim 10, wherein said predetermined time is about 30 seconds.