JPH027414Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to an improvement in the high pressure protection function of an air conditioner equipped with a heat pump type refrigeration cycle.

[Technical background of the invention and its problems]

Generally equipped with a heat pump type refrigeration cycle,
For air conditioners that can selectively perform cooling and heating operations by switching four-way valves, when the indoor temperature rises during heating operation, the pressure on the high pressure side increases, causing a rise in the winding temperature of the compressor motor and There is a problem in that inconveniences such as deterioration of refrigerant gas and refrigerating machine oil occur.

Therefore, as shown in Fig. 1, during heating operation, the change in the high pressure side pressure Pd and the change in the condensing temperature Tc are approximately 1.
Focusing on the fact that it corresponds to 1:1, when the condensing temperature Tc exceeds the set value of 54℃, the operation of the outdoor fan is stopped (off), and when the condensing temperature Tc drops from that state to the set value of 50℃ or less, the outdoor fan is turned off. There is a system in which so-called condensing temperature release control (hereinafter abbreviated as Tc release control) is performed by restarting (turning on) the operation of the fan and thereby preventing a rise in the high-pressure side pressure Pd.

However, if the indoor temperature is high at the start of heating operation, the condensing temperature Tc cannot follow changes in the high-pressure side pressure Pd, which causes the high-pressure switch to operate, resulting in a complete shutdown.

In addition, once a complete stop is reached, operation cannot be restarted unless the user performs manual operation to resume operation, and even if operation is restarted, the high pressure switch will be activated again immediately, so there will be no manual operation by the user. It also has the disadvantage that it requires a certain amount of temperature, and in particular, the condensing temperature Tc does not follow changes in the high-pressure side pressure Pd unless manual operations are performed many times.

[Purpose of invention]

This idea was devised in view of the above circumstances, and its purpose is to provide accurate high-pressure protection according to the situation without completely stopping even if the high-pressure switch is activated at the start of heating operation. enable,
It is an object of the present invention to provide an air conditioner with excellent practicality and reliability that can reduce the burden on a user.

[Summary of the idea]

This idea includes a compressor, four-way valve, outdoor heat exchanger,
In an air conditioner equipped with a heat pump refrigeration cycle in which a pressure reducing device, an indoor heat exchanger, etc. are connected in sequence, and capable of selectively performing cooling operation and heating operation by switching the four-way valve, the high-pressure side of the refrigeration cycle An automatic reset high-pressure switch that activates when the pressure rises abnormally and exceeds a certain value; a temperature sensor that detects the temperature of the indoor heat exchanger; and a temperature sensor that detects the temperature of the indoor heat exchanger. means for stopping all operations of the air conditioner; means for stopping all operations of the air conditioner if the high pressure switch is activated after a certain period of time from the start of operation during heating operation; means for stopping the operation of the compressor and the operation of the outdoor fan near the outdoor heat exchanger when the high pressure switch is activated; If the high-pressure switch does not return to normal operation, a means for stopping all operations of the air conditioner, and if the high-pressure switch returns to normal operation within a predetermined time after stopping the operation of the compressor and outdoor fan, the compressor is stopped after a certain period of time _t1 . The apparatus is equipped with means for restarting only the operation, and means for turning on the operation of the outdoor fan if the temperature detected by the temperature sensor is lower than a set value and turning off the operation if it is higher after _a certain time t2 after restarting the operation.

[Example of idea]

An embodiment of this invention will be described below with reference to the drawings.

In FIG. 1, a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, a pressure reducing device such as a capillary tube 4, an indoor heat exchanger 5, etc. are connected in sequence.
A heat pump type refrigeration cycle is constructed. A high pressure switch 6 is installed on the high pressure side piping of this refrigeration cycle. Further, a temperature sensor such as a thermistor 7 is attached to the indoor heat exchanger 5 to detect the condensation temperature. Further, an outdoor fan 8 is disposed near the outdoor heat exchanger 3. An indoor fan 9 is arranged near the indoor heat exchanger 5.

FIG. 2 shows the control circuit. 20 is the main control unit;
It consists of a microcomputer and its peripheral circuits, and is connected to an AC power supply 21. Thus, a driving operation section 22 is connected to the main control section 20 . Further, 8M is a fan motor of the indoor fan 8, 9M is a fan motor of the outdoor fan 9, 2c is an electromagnetic coil of the four-way valve 2, and 23 is an electromagnetic contactor for the drive motor (compressor motor) of the compressor 11. , these fan motors 8M, 9M, electromagnetic coil 2c, and contactor 23 are connected to an AC power source 21 via a contact circuit of the main control section 20. Furthermore, the main control unit 2
0 is connected to the high voltage switch (normally closed contact) 6 and thermistor 7.

The main control unit 20 has a functional means that stops all operations of the air conditioner when the high pressure switch 6 is activated during cooling operation, and a functional means that stops all operations of the air conditioner when the high pressure switch 6 is activated during heating operation, and when the high pressure switch 6 is activated after a certain period of time from the start of operation during heating operation. A functional means for stopping all operations of the air conditioner, a functional means for stopping the operation of the compressor 1 and the outdoor fan 9 when the high pressure switch 6 is activated within a certain period of time from the start of operation during heating operation; Function means for stopping all operations of the air conditioner if the high pressure switch 6 is not restored within a predetermined time after the compressor 1 and the outdoor fan 9 are stopped; If the high pressure switch 6 is restored within the specified time, the compressor 1 will only be operated after a certain period of time _t1 , and after a certain period of time _t2 , if the temperature detected by the thermistor 7 is lower than the set value, the temperature detected by the thermistor 7 will be outside the room. Juan 9
It is equipped with a functional means to perform Tc release control, which turns on the operation of Tc and turns it off if it is high.

Next, the operation of the above configuration will be explained with reference to FIGS. 4 and 5. In addition, in Fig. 5, A is the compressor 1, B is the four-way valve 2, and C is the four-way valve 2.
represents the outdoor fan 8, and D represents the indoor fan 9.

When a heating operation is started using the operating unit 22, the compressor 1, the outdoor fan 8, and the indoor fan 9 start operating, and the four-way valve 2 is switched. In other words, heating operation is started.

At the start of this heating operation, if the indoor temperature is not high, the pressure on the high pressure side will not rise suddenly. In other words, the condensation temperature Tc of the indoor heat exchanger 5 detected by the thermistor 7 will be sufficient to compensate for the change in the pressure on the high pressure side. This allows Tc release control to be performed in the same manner as in the past.

By the way, at the start of heating operation, if the indoor temperature is high, the pressure on the high pressure side will rise rapidly, and the high pressure switch 6 will
is activated. If the activation of the high pressure switch 6 occurs within a certain period of time, for example, 2 minutes, the main control unit 20 determines that the abnormal rise in high pressure side pressure is due to the startup, and does not perform a complete shutdown. Then, the operation of the compressor 1 and the outdoor fan 8 are stopped and the pressure on the high pressure side is measured to decrease. However, the main control unit 20 is configured to turn on the high pressure switch 6 within a predetermined period of time, for example, 30 seconds after the compressor 1 and the outdoor fan 8 stop operating.
If it does not recover, it is determined that the abnormal rise in pressure on the high pressure side is not due to simple startup but is due to another factor, and a complete shutdown is performed. On the other hand, if the high pressure switch 6 returns within 30 seconds, the operation of the compressor 1 and the outdoor fan 8 continues to be stopped. Then, when the operation stop continues for a certain period of time _t1 , for example, 3 minutes, only the compressor 1 resumes operation. Further, when only the compressor 1 continues to operate for a certain period of time _t2 , for example, 2 minutes, the main control section 20 starts Tc release control.

Note that, if the high pressure switch 6 is activated after restarting the operation of only the compressor 1, the main control unit 20 performs a complete stop. In addition, an internal counter counts the number of times the high-pressure switch 6 is operated, allowing up to one operation at the start of operation, and a complete stop at the second operation. It measures the time, and when the elapsed time reaches 60 minutes, the number of operations N is initialized (set to "0"),
We are trying to deal with the next operation start control.

In this way, even if the high-pressure switch is activated at the start of heating operation, it does not completely stop the system, making it possible to provide accurate high-pressure protection according to the situation, eliminating the need for the user to repeatedly perform manual operations to return to operation. is gone,
Very convenient.

It should be noted that this invention is not limited to the above circumstances, and it goes without saying that various modifications can be made without changing the gist.

[Effect of idea]

As described above, according to this invention, even if the pressure on the high pressure side rises abnormally at the start of heating operation, it does not completely stop, making it possible to provide accurate high pressure protection according to the situation, reducing the burden on the user. It is possible to provide an air conditioner with excellent practicality and reliability that can reduce the burden on customers.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining condensing temperature release control, Fig. 2 is a block diagram of a heat pump type refrigeration cycle in an embodiment of this invention, Fig. 3 is a schematic block diagram of a control circuit in the same embodiment, FIG. 4 is a diagram for explaining the operation of the same embodiment, and FIG. 5 is a flowchart for explaining the operation of the same embodiment. 1... Compressor, 2... Four-way valve, 5... Indoor heat exchanger, 6... High pressure switch, 7... Thermistor (temperature detector), 8... Outdoor fan, 20... Main control unit.

Claims (1)

[Scope of utility model registration request] It is equipped with a heat pump type refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, a pressure reduction device, an indoor heat exchanger, etc. are connected in sequence, and cooling operation and heating operation can be selectively performed by switching the four-way valve. In the air conditioner, an automatic reset type high pressure switch that operates when the high pressure side pressure of the refrigeration cycle increases abnormally and exceeds a certain value, a temperature sensor that detects the temperature of the indoor heat exchanger, and during cooling operation; means for stopping all operations of the air conditioner when the high pressure switch is activated; and means for stopping all operations of the air conditioner when the high pressure switch is activated after a certain period of time from the start of operation during heating operation; , means for stopping the operation of the compressor and the outdoor fan near the outdoor heat exchanger when the high pressure switch is activated within a certain period of time from the start of operation during heating operation; and the compressor and the outdoor fan. means for stopping all operations of the air conditioner if the high pressure switch does not return within a predetermined time from the stop of operation of the compressor and the outdoor fan; If the temperature detected by the temperature sensor is lower than the set value, the outdoor fan is turned on, and if the temperature detected by the temperature sensor is higher than the set value, the outdoor fan is turned on after a fixed time _t2 after restarting the compressor _. An air conditioner characterized by comprising: a means for turning off the air conditioner.