JPH0236019Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an air conditioner incorporating an electric expansion valve in the refrigeration cycle, and in particular, to quickly adjust the valve opening to suit the load of the refrigeration cycle when starting the compressor. It concerns an adjustable air conditioner.

[Technical background of the invention and its problems] A conventional air conditioner incorporating an electric expansion valve in the refrigeration cycle is explained using Fig. 1. 1 is a compressor, 2 is a four-way valve, and 3 is an outdoor heat exchanger. 4 is an electric expansion valve, and 5 is an indoor heat exchanger, which are connected in sequence to form a refrigeration cycle.

The flow of refrigerant during cooling is as shown by the solid arrow in the figure. After the high temperature, high pressure refrigerant from the compressor 1 enters the outdoor heat exchanger 3 and is condensed there, it is depressurized by the electric expansion valve 4, and then The refrigerant exchanges heat with the indoor air in the indoor heat exchanger 5, evaporates, and returns to the compressor 1 through the four-way valve 2. During heating, the four-way valve 2 is switched, and the refrigerant flow is shown in the cooling and reverse cycle. The flow is shown by the dotted arrow. That is, the high-temperature, high-pressure refrigerant from the compressor 1 flows through the four-way valve 2 to the indoor heat exchanger 5, where it exchanges heat with indoor air and condenses, and then is depressurized by the electric expansion valve 4 and then transferred to the outdoor heat exchanger 3. It evaporates and becomes a flow that returns to the compressor 1 via the four-way valve 2.

In this refrigeration cycle, the valve opening degree of the electric expansion valve 4 is adjusted by superheat control, a set target degree of superheat T ₀ is determined in advance, the degree of superheat ΔT detected within the cycle is detected, and the degree of superheat ΔT
The valve opening degree is adjusted so that the target superheat degree T ₀ is reached.

That is, for example, in the case of cooling operation, the refrigerant evaporation temperature (or saturated liquid temperature) in the indoor heat exchanger 5
Te and the suction temperature Ts of the compressor 1 are detected, and in the case of heating operation, the refrigerant evaporation temperature Te in the outdoor heat exchanger 3 and the suction temperature Ts of the compressor 1 are detected, and the suction temperature Ts and the evaporation temperature Ts are detected. Difference from temperature Te, ΔT=Ts−
Te, that is, the degree of superheating ΔT of the refrigerant in the cycle is detected, and the valve of the electric expansion valve 4 is opened and closed according to the difference between the degree of superheating ΔT and the set target degree of superheat _T0 , as shown in Fig. 2. The degree of superheating ΔT in the cycle is detected at regular intervals as shown in _FIG . The valve opens so that the superheat degree ΔT reaches the target superheat degree T ₀
If the opening is smaller than the set opening, the valve is closed so that the opening is smaller than the set opening, and this is repeated to achieve stable operation in which the superheating degree ΔT becomes the set opening of the target superheating T ₀ .

The opening degree of the electric expansion valve 4 is adjusted by a pulse motor, and the opening degree is adjusted by the number of pulses sent to the motor, and as shown in FIG. The set number of pulses when the target superheat degree T ₀ is set is determined in advance, and if the superheat degree ΔT is larger than T ₀ , the number of valve opening pulses larger than the set pulse number is sent, and the _number of valve opening pulses larger than the set pulse number is If the number of pulses is smaller than the set number of pulses, the number of valve-closing pulses smaller than the set number of pulses is sent to the pulse motor to control the opening and closing of the expansion valve 4.

However, when starting the operation of the compressor 1, if the electric expansion valve 4 is fully closed, fully opened, or the valve opening is controlled as described above from the opening set in the cooling/heating mode, ΔT=T at the opening according to the load. It takes time to reach stable operation at ₀ . In particular, even though the load on the refrigeration cycle changes depending on the indoor temperature and outdoor temperature at the start of operation, the same opening/closing control is performed at the same rate, and there is a problem in that it takes a considerable amount of time to achieve stable operation.

[Purpose of the invention] This invention was made in consideration of the above circumstances.
The purpose of the present invention is to provide an air conditioner that can quickly and stably operate by detecting the load on a refrigeration cycle at the start of operation.

[Summary of the invention] The present invention is a refrigeration cycle in which an electric expansion valve whose valve opening is adjusted by a pulse motor is installed between an outdoor heat exchanger and an indoor heat exchanger, and which drives the electric expansion valve. A temperature sensor detects the indoor or outdoor temperature, and when the compressor is started, input is input to the valve drive circuit so that the valve opening degree corresponds to the output of the temperature sensor, and the valve drive circuit detects the temperature. It is characterized by comprising a main control circuit that starts the compressor after adjusting the expansion valve to the valve opening degree according to the output of the sensor, and starts the compressor after turning on the main power or during heating and cooling. , the compressor stops,
When starting up the compressor, the indoor or outdoor temperature is detected, the opening of the expansion valve is set accordingly, and the compressor is started for cooling/heating operation, allowing for quick and stable operation. This is what I did.

[Embodiment of the invention] Hereinafter, a preferred embodiment of the air conditioner according to the invention will be described based on the accompanying drawings.

FIG. 4 shows an air conditioner according to the present invention. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, and 4 is an electric motor whose valve opening is adjusted by, for example, a pulse motor. 5 is an indoor heat exchanger, which are connected in sequence to form a refrigeration cycle. The flow of refrigerant during cooling is the same as explained in the conventional example in Fig. 1, from the compressor 1 to the four-way valve 2, to the outdoor heat exchanger 3, to the electric expansion valve 4, and to the indoor heat exchanger as shown by the solid arrow in the figure. The flow returns to the compressor 1 via the four-way valve 2 through the compressor 5, and during heating, the flow flows from the compressor 1 to the four-way valve 2, the indoor heat exchanger 5, the electric expansion valve 4, and the outdoor heat exchanger as shown by the dotted arrow. Four-way valve 2 through vessel 3
The flow returns to the compressor 1 via .

The electric expansion valve 4 is provided with a pulse motor (not shown) that drives the valve body (not shown) of the expansion valve 4, and the pulse motor is driven by a pulse signal from the valve drive circuit 6. The valve opening degree is adjusted. This adjustment of the valve opening is performed by superheat control, and the outputs of the evaporation temperature sensor 7 that detects the evaporation temperature Te of the refrigerant and the suction temperature sensor 8 that detects the suction temperature of the compressor 1 are sent to the valve drive circuit 6. As explained in FIG. 3, the valve drive circuit 6 sends a pulse signal corresponding to the degree of superheat ΔT of the cycle to the electric expansion valve 4, and the valve opening degree is adjusted to correspond to the degree of superheat ΔT.

The compressor 1 is started by a signal 10 from the main control circuit 9. The main control circuit 9 receives the output of a temperature sensor 11 that detects indoor temperature or outdoor temperature. Based on the detection output of the temperature sensor 11, the main control circuit 9 inputs a signal 12 to the valve drive circuit 6 so that the valve opening degree corresponds to the indoor or outdoor temperature, as shown in FIG.

Next, the operation of the present invention will be explained.

When the compressor 1 is started, that is, when the main power is turned on and the refrigeration cycle starts operating, or during cooling/heating operation, the operation switch is turned ON to control the indoor temperature.
When the compressor 1 is turned off and the operation switch is activated, the temperature sensor 11 first detects the indoor temperature or the outdoor temperature, and its output is input to the main control circuit 9. This main control circuit 9 controls the electric expansion valve 4 at startup according to the output of the temperature sensor 11.
A signal 12 is sent to the valve drive circuit 6 so that the valve opening corresponds to the indoor or outdoor temperature, and the electric expansion valve 4 is adjusted by the valve drive circuit 6 to the valve opening corresponding to the output of the temperature sensor 11. Ru. After the opening degree of the expansion valve 4 is adjusted, the compressor 1 is activated by a signal 10 from the main control circuit 9.

By adjusting the opening degree of the electric expansion valve 4 according to the indoor or outdoor temperature, the opening degree is adjusted to match the load, and thereafter stable operation at ΔT=T ₀ can be quickly achieved.

In the above embodiment, the evaporation temperature sensor 7 is provided between the outdoor heat exchanger 7 and the electric expansion valve 4, but the evaporation temperature sensor 7 does not necessarily detect the evaporation temperature Te of the refrigerant during cooling. Although it is not installed, super heat control can be performed even if it is installed in this position. Also, at startup, the evaporation temperature sensor 7 is approximately the same as the outdoor temperature, so the output of the evaporation temperature sensor 7 is input to the main control circuit 9, and the valve opening of the electric expansion valve is set using the detected output. It may be configured as follows.

[Effects of the Invention] As is clear from what has been described in detail above, the present invention provides the following excellent effects.

(1) A temperature sensor is installed to detect indoor or outdoor temperature, and when the compressor is started, the electric expansion valve is adjusted to the valve opening according to the detected temperature, and then the compressor is started. Stable operation can be achieved over time.

(2) Since the opening degree of the expansion valve at startup is set according to the indoor or outdoor temperature, operation can be performed in accordance with the load.

[Brief explanation of the drawing]

Figure 1 is a diagram showing a conventional air conditioner, Figure 2 is a graph showing the relationship between the degree of superheat and the valve opening of the expansion valve in the case of superheat control, and Figure 3 is a graph showing the relationship between the degree of superheat and the opening degree of the expansion valve in the case of superheat control. A graph showing the relationship between the pulse signal for opening and closing, FIG. 4 is a diagram showing an embodiment of the air conditioner according to the present invention, and FIG. 5 is a graph showing the relationship between the indoor or outdoor temperature and the air conditioner according to the present invention. It is a graph showing the relationship between the valve opening degree of the electric expansion valve at the time of startup. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is an electric expansion valve, 5 is an outdoor heat exchanger, 6
9 is a valve drive circuit, 9 is a main control circuit, and 11 is a temperature sensor.

Claims (1)

[Scope of utility model registration request] An electric expansion valve is installed between the outdoor heat exchanger and the indoor heat exchanger, and the valve opening degree of the electric expansion valve is determined in advance by the degree of superheating determined by the difference between the refrigerant evaporation temperature of the evaporator and the refrigerant temperature on the suction side of the compressor. In a refrigeration cycle that is adjusted by superheat control to achieve a set target degree of superheat, a valve drive circuit that drives the pulse motor of the electric expansion valve, a temperature sensor that detects indoor or outdoor temperature, and a compressor. At startup, a signal is input to the valve drive circuit so that the valve opening degree corresponds to the output of the temperature sensor, giving priority to the superheat control, and at the same time, the valve drive circuit controls the valve opening degree according to the output of the temperature sensor. and a main control circuit that starts the compressor after adjusting the expansion valve.