JPS608661A - Refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a refrigeration system using a variable capacity compressor and a pressure reducing device whose valve opening can be adjusted.

(b) Prior art In a refrigeration system using a compressor with variable capacity and a pressure reducing device with adjustable valve opening, the valve opening was adjusted based on the refrigerant temperature in the evaporator.

However, the amount of refrigerant discharged from a compressor with variable capacity fluctuates dramatically depending on the load, and even if the opening degree of the valve is adjusted according to the refrigerant temperature in the evaporator, this valve will only adjust to the refrigerant temperature on the low-pressure side of the refrigeration circuit. Since the opening of the valve was not controlled promptly according to the temperature of the refrigerant discharged from the compressor, the degree of throttling could not be maintained so that the degree of superheat in the refrigeration circuit remained constant. .

(c) Purpose of the Invention The degree of opening of the valve is adjusted according to the temperature of the refrigerant discharged from the compressor, the temperature is quickly brought within a certain range, and the degree of restriction is adjusted so that the degree of superheating in the refrigeration circuit is constant. It is intended to be maintained as such.

2) A control system in which a refrigeration circuit is formed by connecting the variable capacity compressor of the invention, a condenser, a pressure reducing device whose valve opening can be adjusted, and an evaporator in a ring with refrigerant piping, and adjusting the valve opening. The main detector of the device was arranged in the discharge pipe of the compressor, and the sub-detector was arranged in the evaporator, and pressure was applied so that the control device 6 was operated preferentially by the detection signal of the main detector rather than the sub-detector. It is something.

(E) Example In FIG.
(2) is a four-way valve that switches the flow of refrigerant between cooling operation and heating operation.

(3) is an outdoor heat exchanger that acts as a condenser during cooling operation and as an evaporator during heating operation. (4) is a pressure reducing device, and the opening degree of a valve (not shown) is adjusted using a control device, which will be described later. It acts as a condenser during heating operation.

These compressor (1), four-way valve (2), outdoor heat exchanger (3), pressure reduction device (4), and indoor heat exchanger (5) are connected in a ring shape with refrigerant piping to form a refrigeration circuit. There is. (6 idiots are sub-temperature detectors for cooling, respectively, and indoor heat exchanger (5)
and an outlet pipe (8) when this heat exchanger is used for cooling. In addition, each rib (9) is a sub-temperature detector for heating, and the intermediate part of the outdoor heat exchanger (3) and the outlet piping 0 when this heat exchanger is used for heating.
It is located at υ. The 0 hot water is the main temperature detector and is installed in the discharge pipe (13) of the compressor (1).

α (a) is a control device that adjusts the opening degree of the valve of the pressure reducing device (4), and the five temperature detectors (6) (force (9+(1)
0) The detection signal from Q is input.

This control device a4 includes a first controller (14a), a second controller (14b), and a third controller (14c). The first controller (14a) receives the signal from the main temperature detector Oz, and as shown in FIG. When the slope is above the setting curve shown by the solid line (the change in the discharge refrigerant temperature is small for a certain period of time), the valve opening degree is set to the limit, and when the slope is below the solid line (the change in the discharge refrigerant temperature is small for a certain period of time) 5 to keep the valve in the set state when there is a large change in temperature. In addition, when the temperature gradient is above the set curve shown by the solid line in the upper limit range (T, I, ~Tn2) where the discharge refrigerant temperature is high (the change in the discharge refrigerant temperature is small over a certain period of time), the valve is maintained at the set state, and when the temperature is below the solid line (the change in discharged refrigerant temperature is large over a certain period of time), the opening degree of the valve is set to be increased.

In this way, the temperature of the refrigerant discharged from the compressor (1) is monitored by the main temperature detector (121), and in the lower limit range, the compressor prevents liquid compression, and in the upper limit range, the refrigerant is discharged while protecting the compressor from burning out. Region where the refrigerant temperature is appropriate ('rL.

~T, I, ).

The second controller (14b) operates when the temperature of the refrigerant discharged from the compressor (1) during cooling operation is in the range TL2 to Tlf, and the indoor heat exchanger (5) acts as an evaporator. Also, calculate the difference (8゛r2) between the temperature difference value of the two sub-temperature detectors (6) and (7) disposed on the outlet pipe 181 and the preset temperature value, As shown in Figure 3, this difference (ΔT,) is -0.5℃〈ΔT2
〈If it is +0.5℃, the opening degree of the valve of the pressure reducing device (4) is maintained at the preset state, and if it is -4.0℃〈△Tt＜
If it is 0.5°C, the opening degree of this valve is made smaller than the set state, and if ΔT2 < 4.0°C, the opening degree of this valve is made smaller than the set state. On the other hand, if the difference (△T2) is +0.5°C〈△T, (+4.0°C), the opening degree of this valve is made larger than the set state, and if ∆T2 > +4.0°C, the opening degree of this valve is increased. Make it even larger than the normal setting state.

In the above explanation, the valve opening setting state refers to the compressor (
It means the degree of throttling of the valve that provides the optimum refrigerating capacity determined from the rated capacity of 1) and the heat exchange capacity of the indoor heat exchanger (5) and the outdoor heat exchanger (3).

The third controller (14c) is designed to operate in a region where the temperature of the refrigerant discharged from the compressor (1) is TL2 to TL11 during heating operation, and is an outdoor heat exchanger that functions as an evaporator. (3) and 2 installed in the outlet pipe (11)
Calculate the difference (8'r3) between the temperature difference value of the two sub-temperature detectors (9i (1 (1)) and the preset temperature value, and similarly to the second controller (14b), calculate this difference ( Δ′F,) is the third
The opening degree of the valve is set to open side 1 according to the conditions shown in the figure.

Next, the operation will be explained.

First, cooling operation will be explained.

When the compressor (1) is operated with the four-way valve (2) indicated by the solid line at ℃ in Fig. 1, the refrigerant flows as shown by the solid line arrow, and the refrigerant discharged from the compressor (1) is discharged from the four-way valve (2). 2), is cooled in an outdoor heat exchanger (3), and is further transferred to a pressure reducing device (4).
It is depressurized and flows into the indoor heat exchanger (5). This indoor heat exchanger (5) cools the room using the heat absorbed when the refrigerant evaporates. At the start of this cooling operation, the opening degree of the valve of the pressure reducing device (4) is maintained at the set state. During this cooling operation, 3011z~1 depending on the cooling load.
20) Supply the frequency of an arbitrary power source of 1z to the compressor (1). For example, when the cooling load is large, the compressor (11
The frequency of the power supplied to the device is set high. and,
When the temperature of the refrigerant discharged from the compressor (1) exceeds T+n, it becomes difficult to protect the windings of the compressor (1).
Ru. In this case, the main detector +121 detects the temperature of this refrigerant, and when the temperature change is large (below the set curve in Figure 12), a signal is sent from the first controller (14a). The opening degree of the valve of the pressure reducing device (4) is increased to reduce the pressure reducing resistance value. Then, a large amount of refrigerant is caused to flow into the indoor heat exchanger (5) to quickly bring the temperature of the refrigerant discharged from the compressor (1) below Tl11, and the windings of the compressor (1) are maintained. There is. That is, the temperature of the refrigerant discharged from the compressor (1) is lowered, and the second controller (14b
) to adjust the degree of throttling so that the degree of superheating in the refrigeration circuit remains constant.

At this time, the operation of the third controller (14C) is stopped.

Further, when the cooling load is small, the frequency of the power supply supplied to the compressor (1) is set low. If the temperature of the refrigerant discharged from the compressor (1) is below T.2, there is a risk that liquid compression will occur. In this case, the main detector 02 detects the temperature of this refrigerant, and when the change in temperature is small (it is above the set curve in Figure 2), the GL controller (14a)
The opening degree of the valve of the pressure reducing device (4) is decreased by the signal from the pressure reducing device (4), and the pressure reducing resistance value is increased. Therefore, since a small amount of refrigerant flows into the indoor heat exchanger (5), the temperature of the compressor (1) gradually rises, and the temperature of the discharged refrigerant also rises, so that l1lL2
is reached and liquid compression is prevented. That is, compressor (1)
The temperature of the refrigerant discharged from the refrigeration circuit is increased, and the degree of throttling is adjusted by a second controller (14b), which will be described later, so that the degree of superheat in the refrigeration circuit is constant. At this time, the operation of the third controller (14c) is stopped.

Also, the temperature of the refrigerant discharged from the compressor tll is 'I'L.
In the range 2 to T, II, the second controller (14b) is activated, and this second controller (14b) detects the temperature difference between the two sub-temperature detectors (which is set in advance with the value of the temperature difference of 6). Calculate the difference (8゛r2) from the temperature value of
0.5℃, -0.5℃＜ΔTz＜+o, ! 5
°C, +0.5 °C (Δ'r, <+4.0 °C, ΔT2 >
The opening degree of this valve is adjusted separately when the temperature is +4.0°C.

In this way, the temperature of the refrigerant discharged from the compressor (1) is detected by the main temperature detector (13), and this signal operates the control device (14) preferentially, and the first controller (14a) reduces the pressure. Adjust the opening degree of the valve of the device (4) to quickly bring the temperature of the refrigerant discharged from the compressor (1) into an appropriate range (TL2~'r,
I, ). Thereafter, based on the temperature of the refrigerant flowing through the indoor heat exchanger (5), the second controller (14b) adjusts the opening degree of the valve to keep the degree of superheat constant.

Next, during heating operation, when the four-way valve (2) is set to the broken line state and the compressor (1) is operated, the refrigerant flows as shown by the broken line arrow (flow is condensed and liquefied in the indoor heat exchanger (5). At the start of this heating operation (f), the opening and closing of the valve of the pressure reducing device (4) is maintained at the set state.

During this heating operation, 3011y, depending on the heating load,
A power frequency of ~120Hz is supplied to the compressor (1). That is, when the heating load is large, the frequency of the power supply is set high, and when the heating load is small, the frequency of the power supply is set low. J) The temperature of the refrigerant discharged from the compressor (1) fluctuates as the frequency of the power supply is set. This fluctuating temperature is detected by the main detector (12), and the temperature of the discharged refrigerant is TL.
2 or less or '1゛□.

In the above case, the first controller (14a) first uses the pressure reducing device σ(4).
)σ) Adjust the opening degree of the valve in the same way as when cooling, and compress (f4
(11σ) The temperature of the discharged refrigerant is shifted to the range of ``L2~Tl11.Then, the third controller (14c) is used to control the outdoor heat exchanger (3) acting as an evaporator and its outlet piping (1υ). Two sub-temperature detectors (91F+
Calculate the difference (Δ'r3) between the temperature difference σ) value of 01 and the preset temperature value, and adjust the opening degree of the valve according to this difference (ΔT, ) according to Fig. 3. . At this time, the operation of the second controller (+4b)σ) is stopped. Even during this heating operation, if the temperature of the refrigerant discharged from the compressor (1) is high or low, first the first controller (14a
) to adjust the opening degree of the valve of pressure reducing device I'l (4J) to quickly shift the temperature of the refrigerant discharged from compression +11 into the appropriate range (T52 to T,,), and then (3) The opening degree of the valve is adjusted based on the temperature of the refrigerant flowing through.

(f) Effects of the invention Equipped with a compressor that can change the refrigerant discharge amount according to increases and decreases in the air conditioning load, the valve of the pressure reducing device is Since the opening degree is adjusted, even if the temperature of the refrigerant discharged from this compressor fluctuates rapidly, this temperature is detected and the opening degree of the valve of the pressure reducing device is controlled to adjust the throttling degree to the refrigeration circuit. The degree of superheat inside can be maintained constant.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a refrigeration circuit diagram;
FIG. 2 is a diagram showing the opening and closing of the valve based on the operation of the first controller,
FIG. 3 is a diagram showing opening and closing of the valve based on the operations of the second and third controllers. (1)...Compressor, (3)...Outdoor heat exchanger,
(4)...pressure reducing device, (5)...indoor heat exchanger,
(6) (Force (9101υ... sub-detector, a2...
・Main detector, 04)...control device.

Claims (1)

[Claims] 1. A variable capacity compressor, a condenser, a pressure reducing device whose valve opening can be adjusted, and an evaporator are connected in an annular manner through refrigerant piping to form a refrigeration circuit, and a control device that adjusts the valve opening. The main detector is arranged in the discharge pipe of the compressor, and the sub-detector is arranged in the evaporator, respectively, and the control device is operated preferentially by the detection signal of the main detector rather than the sub-detector. Refrigeration equipment.