JPH0225105Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air conditioner, and particularly to an air conditioner applicable to commercial heat pump water heaters, air-cooled heat pump chillers, and the like.

A conventional air conditioner will be explained based on FIGS. 1 to 3.

Figure 1 is a diagram showing the configuration of a conventional air conditioner, in which 1 is a compressor, 2 is a four-way switching valve, 3 is a water heat exchanger, 4 is an expansion device, 5 is an air heat exchanger, and 6 is a blower. show. Reference numeral 7 denotes a de-Icer, and its temperature-sensing part is disposed between the expansion device 4 and the air heat exchanger 5 in a pipe near the air heat exchanger 5 side. Reference numeral 8 denotes an electric motor for blowing air, which drives the blower 6. 10 is a relay. 12 is an overcurrent relay, which is a protection device for the compressor 1. The de-icer 7 is interlocked with the four-way switching valve 2, the relay 10, and the blower electric motor 8. An example of an electric circuit that performs this interlocking operation is shown in FIG. In FIG. 2, 10b is a contact of the relay 10, and 10a is a coil of the relay 10. 7a and 7b are contacts of the de-icer 7.
Other symbols are the same as in FIG.

In FIG. 1, refrigerant compressed by a compressor 1 passes through a four-way switching valve 2, exchanges heat with water in a water heat exchanger 3, radiates heat, and heats and condenses the water.
The refrigerant is further expanded to a low pressure in the expansion device 4, absorbs heat from the air in the air heat exchanger 5 blown by the blower 6, evaporates, and returns to the compressor 1 again.

When the outside air temperature becomes low and frost forms on the air heat exchanger 5, the suction pressure of the compressor 1 decreases and the temperature of the inlet pipe of the air heat exchanger 5 decreases. 7 is activated.
That is, in FIG. 2, the contact moves from de-iser contact 7a to contact 7b, relay coil 10a is energized, relay contact 10b is opened, and blower motor 8 stops operating.

On the other hand, since the power supply to the four-way switching valve 2 is stopped, the flow of the refrigerant is reversed, and as shown by the broken line arrow in FIG. The refrigerant passes through the heat exchanger 5, heats and melts the frost, radiates heat, and condenses. Furthermore, the expansion device 4
The pressure becomes low at , absorbs heat from water at the water heat exchanger 3 , passes through the four-way switching valve 2 again, and returns to the compressor 1 . That is, a defrost operation is performed. When the frost in the air heat exchanger 5 melts, the high pressure rises, and the temperature at the outlet of the air heat exchanger 5 also rises, and the de-icer 7 returns to its original position and moves to the contact point 7a, again as shown by the solid line arrow in FIG. A heating operation is performed.

However, in the conventional air conditioner described above, during the defrost operation, as the frost formed on the air heat exchanger 5 melts, the operating current of the compressor 1 gradually increases over time as shown in FIG. As a result, the outlet temperature of the air heat exchanger 5 also rises when viewed from the refrigerant flow direction, and the de-icer 7 returns to its normal state, that is, moves from the contact point 7b to the contact point 7a, and the four-way switching valve 2 switches. When the water temperature is high, both the high pressure and the low pressure are high, which causes the compressor 1 to operate under an overload, causing the overcurrent relay 12 as a protection device to operate, causing the compressor 1 to stop.

Note that when the water temperature of the water heat exchanger 3 is low, the overcurrent relay 12 does not operate because the discharge pressure and suction pressure of the compressor at the end of defrost are low.

The present invention was proposed in view of the above circumstances, and its purpose is to prevent the overcurrent relay of the compressor from operating when the defrost operation ends and the heating operation is switched to. is to provide.

The air conditioner according to the present invention is equipped with a compressor, a four-way switching valve, a water heat exchanger, an expansion device, and an air heat exchanger. In the air conditioner being operated, a detection means for detecting the water temperature in the water heat exchanger is provided, and the four-way switching valve is switched when the water temperature detected by the detection means is equal to or higher than a set value at the end of the defrosting operation. The water heat exchanger is equipped with a thermostat that detects the water temperature in the water heat exchanger, and when the water temperature is high, the thermostat is installed for a certain period of time after the de-iser returns. When the four-way switching valve is switched over with a delay and the water temperature is low, the four-way switching valve is switched immediately when the de-Iser returns, thereby solving the above-mentioned drawbacks of the conventional system.

Fig. 4 is a schematic diagram showing the configuration of an embodiment of the present invention, Fig. 5 is a diagram showing an electric circuit of the embodiment shown in Fig. 4, and Fig. 6 is a time diagram of the embodiment shown in Fig. 4. FIG. 3 is a diagram showing changes in compressor operating current with respect to

In Fig. 4, 1 is a compressor, 2 is a four-way switching valve,
3 is a water heat exchanger, 4 is an expansion device, 5 is an air heat exchanger, and 6 is a blower. Reference numeral 7 denotes a de-Icer, the temperature-sensing part of which is disposed between the expansion device 4 and the air heat exchanger 5 in the piping on the air heat exchanger 5 side. 8 is an electric motor for blowing air, and drives the blower 6. 9 is a timer, 10 is a relay, and 11 is a water temperature thermostat, which is disposed in the water heat exchanger 3 so that the water temperature in the water heat exchanger 3 can be detected. 12 is an overcurrent relay which is a protection device for the compressor 1. The de-icer 7, the timer 9, the four-way switching valve 2, the blower motor 8, the relay 10, and the water temperature thermostat 11 are interlocked with each other, and one embodiment of their electric circuit is shown in FIG.

In FIG. 5, a timer coil 9a, a timer contact 9b, a four-way switching valve 2, and a water temperature thermostat 11 are arranged at the contact 7a of the de-icer 7 as shown in FIG.

Furthermore, a relay 10 is connected to the contact 7b of the de-icer 7.
A coil 10a is connected thereto. Further, the blowing motor 8 and the relay contact 10b are arranged in series.

The operation of the embodiment of the present invention described above will be explained.

4 and 5, the refrigerant compressed by the compressor 1 passes through the four-way switching valve 2, exchanges heat with water in the water heat exchanger 3, removes heat, and condenses. Furthermore, it expands in the expansion device 4 to become low pressure, absorbs heat from the air in the air heat exchanger 5 blown by the blower 6, evaporates, and returns to the compressor 1.
Return to

When the outside air temperature decreases and frost forms on the air heat exchanger 5, the low pressure decreases and the temperature of the inlet pipe of the air heat exchanger 5 decreases, so when the temperature is detected by the de-icer 7 and the de-icer 7 is activated, the contact 7a 7b
Since the relay coil 10a is energized, the contact 10b is opened and the blower electric motor 8 is stopped. On the other hand, the four-way switching valve 2 is switched because it is not energized, and as shown by the broken line arrow in FIG. It becomes low pressure at the water heat exchanger 3, absorbs heat at the water heat exchanger 3, passes through the four-way switching valve 2, and returns to the compressor 1 (defrost operation).

When the frost in the air heat exchanger 5 is completely melted, the high and low pressures rise, and the air heat exchanger 5 increases when viewed from the direction of the refrigerant flow.
As the temperature of the outlet pipe increases, the de-icer 7 detects the temperature, and the de-icer 7 returns to the contact point 7b.
It moves from to contact point 7a. When the water temperature in the water heat exchanger 3 is low, the water temperature thermostat 11 closes, so the four-way switching valve 2
is energized and the four-way switching valve 2 is switched, and the relay coil 10a is de-energized and the relay contact 10b is switched.
is closed, the blower electric motor 8 is operated, and heating operation is performed again as shown by the solid line arrow in FIG.

In addition, if the water temperature in the water heat exchanger 3 is high,
Immediately after the de-icer 7 returns, the blower motor 8 starts operating, but since the water temperature thermostat 11 opens, the timer 9 closes the timer contacts 9b after a certain period of time delay after energizing the timer coil 9a due to the action of the timer 9. The switching valve 2 is energized, the four-way switching valve 2 is switched, and heating operation is started.

As described above, according to the present invention, when the water temperature in the water heat exchanger 3 is low during defrost operation, the water temperature thermostat 11 detects the water temperature in the water heat exchanger 3, and when the de-icer 7 returns, the water temperature in the water heat exchanger 3 is detected. Switching valve 2
At the same time, the blower 6 also rotates and enters heating operation. This is similar to the conventional defrost recovery operation, but the discharge pressure and suction pressure of the compressor 1 are also low and the overcurrent relay 12 does not operate. However, when the water temperature in the water heat exchanger 3 is high, the four-way switching valve 2 switches as the de-icer 7 returns, and the blower 6
When the compressor 1 rotates, the overcurrent relay 12 of the compressor 1 is activated, so the water temperature thermostat 11 detects the water temperature of the water heat exchanger 3, and at the same time as the de-icer 7 returns, only the blower 6 is rotated. As shown in FIG. 6, since the discharge pressure and suction pressure of the compressor 1 decrease, the operating current of the compressor 1 also decreases. Even if the four-way switching valve 2 is switched in such a state, the compressor 1
The overcurrent relay 12 does not operate. Therefore,
It is possible to return from defrost operation to heating operation without any problem. In this case, the defrost operation will be prolonged by the time delayed by the timer 9.

As described above, according to the present invention, the water temperature of the water heat exchanger 3 is detected by the water temperature thermostat 11, and the four-way switching valve 2 is delayed when the water temperature is higher than the water temperature condition that activates the overcurrent relay 12 of the compressor 1. This provides excellent effects such as minimizing defrost loss and preventing the overcurrent relay 12 from operating.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the configuration of the conventional example, Fig. 2 is a diagram showing the electric circuit of the conventional example, Fig. 3 is a diagram showing the change in compressor operating current with respect to time in the conventional example, and Fig. 4 is a diagram showing the change in compressor operating current with respect to time in the conventional example.
The figure is a schematic diagram showing the configuration of an embodiment of the present invention.
The figure shows an electric circuit of an embodiment shown in FIG.
FIG. 6 is a diagram showing changes in the compressor operating current with respect to time in the embodiment shown in FIG. 4. 1... Compressor, 2... Four-way switching valve, 3... Water heat exchanger, 7... De-Isa, 9... Timer, 10...
...Relay, 11...Water temperature thermostat, 12...
...Overcurrent relay.

Claims (1)

[Scope of utility model registration request] Compressor, four-way switching valve, water heat exchanger, expansion device,
In an air conditioner that includes an air heat exchanger and performs defrosting operation by switching the four-way switching valve using a de-icer that controls the start and end of defrosting operation, the air conditioner includes a detection means for detecting the water temperature in the water heat exchanger. An air conditioner further comprising a delay means for delaying switching of the four-way switching valve when the water temperature detected by the detection means at the end of defrosting operation is equal to or higher than a set value.