JPS6244279Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to an improvement to an air conditioner that uses an electric expansion valve for cooling and heating.

[Technical background of the invention and its problems]

In the case of an air conditioner, an electric expansion valve is provided between the indoor heat exchanger and the outdoor heat exchanger,
Some models use a refrigeration cycle that can perform cooling and heating operations, and repeatedly start and stop in response to changes in indoor temperature. This type of air conditioner uses control to adjust the opening of an electric expansion valve depending on the refrigeration cycle temperature during cooling and heating operations, and to start and stop the compressor that makes up the refrigeration cycle according to room temperature conditions. This is done to provide good cooling or heating.

However, in such an air conditioner, there is a problem that it takes a considerable amount of time to balance the gas in the refrigeration cycle when the operation is stopped. That is, when cooling or heating operation is stopped, the electric expansion valve stops at a certain throttle opening. For this reason, the opening degree of the electric expansion valve becomes a large resistance and delays gas balance. If such gas balance takes a long time, it will take a considerable amount of time for the cooling or heating operation to stop and restart again, which will inadvertently increase the indoor load and cause discomfort. This would have caused problems.

Therefore, in view of this point, the conventional method was to
A technique as shown in No. 44568 has been proposed. This is a method in which the electric expansion valve is fully opened for a certain period of time immediately after the compressor that makes up the refrigeration cycle has stopped; This causes a problem as shown in the electrical circuit in Figure 1, that is,
Normally, an electric expansion valve a is placed on the outdoor side f, and a compressor b placed on the outdoor side f is connected in series to a power input plug d via a thermostat (room temperature detection) c installed on the indoor side g. They are connected to form a power supply circuit e. For this reason, thermostat c
In order to obtain electric power to operate electric expansion valve a after compressor b has stopped due to There is a problem that the number of dedicated units increases.

[Purpose of invention]

This idea was made with attention to the above circumstances, and its purpose is to provide an air conditioner that can shorten the gas balance time of the refrigeration cycle when the operation is stopped without increasing the number of crossover wiring. It's about doing.

[Summary of the idea]

By fully opening the electric expansion valve just before the compressor that makes up the refrigeration cycle stops, this device enables the electric expansion valve to extract electricity from the outside of the room, and also allows the electric expansion valve to fully open the electric expansion valve just before the compressor that makes up the refrigeration cycle stops. This is an attempt to shorten the balance time.

[Example of idea]

This invention will be explained below based on embodiments shown in the drawings. In FIG. 2, 1 is a variable capacity compressor connected to an inverter 1a, 2 is a four-way valve for switching between cold and hot, 3 is an outdoor heat exchanger, and 4 is an indoor heat exchanger. Each of these devices is connected to the refrigerant circulation path 5.
are concatenated sequentially. Moreover, an electric expansion valve 6 is provided between the outdoor heat exchanger 3 and the indoor heat exchanger 4, and constitutes a refrigeration cycle 7 capable of cooling and heating operations. Note that 8 is an outdoor fan attached to the outdoor heat exchanger 3, and 9 is an indoor fan attached to the indoor heat exchanger 4. On the other hand, 10 is a control circuit composed of a microcomputer, and on the input side of this control circuit 10, temperature detection elements 11a provided in the outdoor heat exchanger 3 and the indoor heat exchanger 4,
11b are connected via signal lines 12a and 12b. Therefore, the refrigeration cycle temperature can be input to the control circuit 10 through each temperature detection element 11a, 11b. Further, the output side of the control circuit 10 is connected to the motor section of the electric expansion valve 6 via a signal line 13.
The electric expansion valve 6 can be controlled to adjust the opening based on the opening adjustment data for the refrigeration cycle temperature, which is preprogrammed to zero. As shown in FIG. 3, the electrical circuits of each device in the air conditioner configured as described above include a power input plug 14 on the indoor side A, a thermostat 15 that opens and closes depending on the indoor temperature,
Based on the configuration in which the control circuit 10 and the power on/off switch 16 are arranged, and the compressor 1 and the electric expansion valve 6 are arranged on the outdoor side B, the power is opened/closed via the indoor wiring 17, 17 to the power plug 14. The switch 16 and the thermostat 15 are connected in series, and the crossover wiring 1 crosses the indoor side A and the outdoor side B.
8, 18, and an outdoor wiring 19, the compressor 1 is connected in series, and the control circuit 10 and the electric expansion valve 6 are connected in parallel to the indoor side A and the outdoor side B, respectively. There is. A thermostat 15 is connected to the control circuit 10 via a signal line 21.
The compressor 1 can be controlled to start and stop repeatedly through the thermostat 15, based on a temperature that exceeds a preset temperature for cooling or heating to a certain extent. Furthermore, the control circuit 10 is programmed with information to fully open the electric expansion valve 6 immediately before the compressor 1 is stopped, based on a stop signal linked to the room temperature from the thermostat 15.
In the operation of a refrigeration cycle that repeatedly starts and stops, the electric expansion valve 6 is controlled to be fully open immediately before the compressor 1 stops.

Therefore, when performing cooling or heating with the air conditioner configured as described above, the four-way valve 2 is set to the cooling or heating side, and then the power on/off switch 16 is closed to switch between the cooling cycle or heating. A cycle is configured to provide cooling or heating. This cooling or heating is optimally performed by controlling the opening degree of the electric expansion valve 6 in conjunction with the refrigeration cycle temperature.

Then, as such cooling or heating progresses and the indoor temperature exceeds the set temperature, for example -1 or +1 with respect to the set temperature, at that point the electric expansion starts regardless of the current throttle opening of the electric expansion valve 6. After the valve 6 is fully opened, the compressor 1 is stopped, and the cooling or heating operation is temporarily stopped.

Therefore, when the electric expansion valve 6 is fully opened, there is no resistance when balancing the gas in the refrigeration cycle, so the gas balance can be achieved quickly, and the electric expansion valve 6 is fully opened before the compressor 1 stops, which is different from the conventional method. The time required for gas balance can be further shortened compared to when the compressor 1 is fully opened after stopping, and the time until cooling or heating is resumed can be shortened. Therefore, the load inside the room can be reduced and comfortable cooling and heating can be performed. Moreover, since the gas balance is performed before the compressor 1 is stopped, there is an advantage in that the abrupt balance caused by the stoppage of the compressor 1 can be eliminated and vibrations and shocks can be alleviated. In addition, since the electrically operated expansion valve 6 is operated before the compressor 1 is stopped, the electric power required to fully open the valve can be taken from the outdoor side B as shown in Fig. 3. There is no need for any crossover wiring for operating the expansion valve 6.

Note that in the above-described embodiment, only the compressor 1
Although the electric expansion valve 6 is fully opened immediately before the compressor 1 is stopped, the same effect as in the above embodiment can be obtained even if the electric expansion valve 6 is fully opened within a certain period of time immediately before the compressor 1 is stopped.

FIG. 4 shows another embodiment, in which frost formed on the outdoor heat exchanger 3 during heating operation is defrosted without switching the four-way valve 2 to the cooling side. Specifically, when switching from heating to defrosting, the four-way valve 2 remains on the heating side and inputs the compressor 1 to the inverter 1a or the heater 30 shown in FIG.
By short-circuiting the heating system 32 composed of the heat storage body 31, the lining capacitor circuit 32 shown in FIG. In other words, when the capacity of the compressor 1 reaches its upper limit, the electric expansion valve 6 is controlled to be fully open regardless of the control based on the refrigeration cycle temperature, and the compressor is connected to the outdoor heat exchanger 3 through the indoor heat exchanger 4. The purpose is to introduce high-temperature refrigerant discharged from 1. According to this, the seventh
As shown in the figure, when defrosting starts, the input pressure P ₀ of the outdoor heat exchanger 3 suddenly increases and defrosting is performed, and the outlet pressure P ₁ of the indoor heat exchanger 3 decreases slightly. Some heating effect remains,
Defrosting can be performed while maintaining heating capacity. Therefore, non-stop heating can be performed without loss of heating capacity during defrosting. Moreover, since defrosting can be performed without switching the four-way valve 2, the noise caused by switching the four-way valve 2 can be reduced, and pressure fluctuations in the refrigeration cycle caused by liquid refrigerant return etc. can be minimized. It has the advantage of being able to suppress

[Effect of idea]

As explained above, according to this invention, the electric expansion valve is fully opened just before the compressor is stopped, so the gas balance of the refrigeration cycle is maintained when the operation is stopped without increasing the number of crossover wiring. The required time can be effectively shortened, and the time until operation can be resumed can be shortened.

Therefore, it reduces the load inside the room and provides comfortable cooling.
Heating can be performed, and the configuration can be simplified. Furthermore, since the gas balance is performed before the compressor is stopped, there is an advantage in that the sudden imbalance caused by the stoppage of the compressor can be eliminated and vibrations and shocks can be alleviated.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing the electrical operation system of an electric expansion valve of a conventional air conditioner, Fig. 2 is a block diagram showing an air conditioner according to an embodiment of the invention, and Fig. 3 is a circuit diagram thereof. FIG. 4 is a block diagram showing another embodiment of the invention, FIGS. 5 and 6 are block diagrams showing the input systems of the different compressors, and FIG. 7 is a diagram showing the dehumidification characteristics thereof. 1...Compressor, 3...Outdoor heat exchanger, 4...
Indoor heat exchanger, 6... Electric expansion valve, 7... Refrigeration cycle, 10... Control circuit.

Claims (1)

[Scope of utility model registration request] A refrigeration cycle is constructed by installing an electric expansion valve between an indoor heat exchanger and an outdoor heat exchanger, and is capable of cooling and heating operation, and repeatedly starts and stops in response to changes in indoor temperature. type expansion valve,
During cooling/heating operation, the opening degree is adjusted and controlled based on the refrigeration cycle temperature, and when the cooling/heating operation stops due to the stop of the compressor that makes up the refrigeration cycle, it is fully opened just before the compressor stops. An air conditioner characterized by comprising a control circuit.