JPH05126415A - Refrigerator - Google Patents

Abstract

PURPOSE:To have the temperature of a room to be conditioned involved as an operative factor in the control of a motor-operated expansion valve in adjusting its valve opening to an appropriate degree. CONSTITUTION:The refrigerator consists of a refrigeration cycle equipped with a compressor 5, a condenser 3, a motor-operated expansion valve 9, and an evaporator 7 in this sequence and which has a valve opening-adjusting means 12 for adjusting the valve opening of the motor-operated expansion valve 9 to an appropriate degree on the basis of the temperature of the refrigerant in the refrigerant cycle. There is provided also a valve opening-correcting means 13 which, when the refrigeration load falls below a specified value, makes the valve opening of the motor-operated expansion valve 9 greater than the degree that the valve opening-adjusting means 12 has set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus in which the temperature of a refrigerant is detected by a temperature sensor and the valve opening of an expansion valve in a refrigerating cycle is controlled according to the value detected by the sensor.

[0002]

2. Description of the Related Art Conventionally, there has been known an air conditioner which detects a refrigerant temperature during a refrigeration cycle and adjusts a valve opening of an expansion valve based on the detected value (Japanese Patent Publication No. 55-14).
987 publication). In this type, generally, the opening degree of the expansion valve is controlled so as to maximize the capacity of the air conditioner.

[0003]

However, in the conventional configuration, even if the temperature of the room to be conditioned approaches the set temperature, the control is always performed aiming at the target value of the initial refrigerant temperature. After that, the thermo-ON and the thermo-OFF are frequently repeated, and there is a problem that the room temperature is largely changed, comfort is deteriorated, and extra power is consumed to become uneconomical. Further, in the conventional configuration, when the control of the expansion valve is started, the control time interval is constant (for example, every 30 seconds), and if the time interval is constant even when the room temperature approaches the set temperature, the thermostat is turned off.
However, there is a problem that the time until is relatively short, the number of times the thermostat is turned on and off is increased, and the room temperature changes greatly. Furthermore, even when detecting and controlling the difference between the current temperature and the target temperature at a specified point in the refrigeration cycle, if the control time interval is constant, the target temperature will be exceeded and this will contribute to hunting. There's a problem.

Therefore, an object of the present invention is to solve the problems of the above-mentioned conventional techniques and to control the valve opening of the expansion valve to an appropriate opening by setting it at room temperature in the room to be conditioned. It is to provide a refrigerating device that is controlled.

[0005]

In order to achieve the above object, the present invention constitutes a refrigeration cycle by sequentially connecting a compressor, a condenser, an electric expansion valve and an evaporator, and a refrigerant temperature in the refrigeration cycle. In a refrigeration system having an adjusting means for adjusting the valve opening degree of the electric expansion valve to an appropriate opening degree based on the above, when the refrigeration load decreases below a predetermined value, the valve opening degree of the electric expansion valve is opened by the adjusting means. It is characterized in that it is provided with a correction means for making it larger than the degree.

Another aspect of the invention is to construct a refrigeration cycle by sequentially connecting a compressor, a condenser, an electric expansion valve, and an evaporator with a refrigerant pipe, and based on the refrigerant temperature in the refrigeration cycle, a valve of the electric expansion valve. In a refrigerating apparatus having an adjusting means for adjusting the opening degree to a proper opening degree at a constant time interval, when the refrigeration load is reduced to a predetermined value or less, the adjustment interval of the valve opening degree of the electric expansion valve is made longer than the constant time period, The present invention is characterized in that a correction means for reducing the valve opening degree at this time to be smaller than the valve opening degree by the adjusting means is provided.

[0007]

According to the present invention, when the refrigerating load decreases below a predetermined value, that is, when the room temperature approaches a certain set temperature, the valve opening degree of the expansion valve is forcibly made larger than usual, or Since the capacity is reduced by making the valve opening adjustment interval longer than a fixed time after reducing the valve opening, the thermo-ON state and thermo-OFF state are not repeated for a long time, and thermo-ON and thermo-OFF are frequently repeated. It is possible to obtain an extremely comfortable air-conditioning condition because the room temperature fluctuation is reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 is a separation type air conditioner, and the air conditioner 1 is composed of an indoor unit A, an outdoor unit B, and an inter-unit pipe 2 connecting both units. The indoor unit A includes an indoor heat exchanger 3 that acts as an evaporator during cooling operation and a condenser during heating operation, and an indoor fan 4, and the outdoor unit B includes a compressor 5 and a four-way valve 6. , An outdoor heat exchanger 7 acting as a condenser during cooling operation and as an evaporator during heating operation
And an accumulator 8 are built in.

Reference numeral 9 is an electric expansion valve, and a controller 11 for controlling the apparatus of this embodiment is connected to the electric expansion valve 9. This controller 11 is a correction means for controlling the electric expansion valve 9 in a normal time, and a correction for controlling the electric expansion valve 9 in accordance with the temperature of the room in which the indoor unit A is installed. And means 13 and the means 12 and 13 are mutually connected.

The adjusting means 12 has two temperature sensors 16 and 1 for detecting the temperature of the refrigerant in the refrigeration cycle.
7 is connected, and the correction means 13 is connected to the room temperature sensor 1
5 is connected. The one sensor 16 operates only during the heating operation, and the other sensor 17 operates only during the cooling operation.

Next, the operation of the embodiment will be described.

When the four-way valve 5 is switched to change the flow of the refrigerant, the cooling operation or the heating operation is performed. In FIG. 1, the flow of the refrigerant during cooling is indicated by a solid line, and the flow of the refrigerant during heating is indicated by a dotted line.

By the way, during operation, the temperature sensor 16
(Or 17) detects the refrigerant temperature in the refrigeration cycle, and the valve opening degree of the electric expansion valve 9 is controlled to an appropriate opening degree based on the detected value. However, in this embodiment, the control of the valve opening degree is finely controlled in accordance with the room temperature of the room in which the indoor unit A is installed according to the flowchart shown in FIG.

Referring to FIG. 2, after the start, the room temperature sensor 15 _first detects the room temperature T ₁ of the room in which the indoor unit A is installed, and this room temperature T ₁ and the preset temperature T ₀ are set. The absolute value | T ₀ −T ₁ | of the difference is calculated, and this difference | T ₀ −T ₁ | is compared with the first temperature difference Δa, which is also set in advance (step 1). .. Here, if it is determined that the difference | T ₀ −T ₁ | is larger than the first temperature difference Δa, the electric expansion valve 9 is normally controlled via the adjusting means 12 (step 2), and the first temperature difference Δa is controlled. If it is determined that the difference is smaller than the temperature difference Δa, then the correction means 1
The control shifts to step 3 (step 3). In this step 3, for example, the valve opening degree of the electric expansion valve 9 is increased by a predetermined amount, or the target discharge temperature of the refrigerant is decreased.
The coolant temperature target value is changed in the direction of decreasing the capacity.

In the next stage, the room temperature sensor 15 detects the room temperature T ₂ again, and the absolute value │T ₀ -T ₂ │ of the difference between the room temperature T ₂ and the preset temperature T ₀ is determined. This difference | T ₀ −T ₂ | is compared with a second temperature difference Δb (where Δb <Δa), which is also set in advance (step 4), and the difference | T ₀ −T ₂ | 2 temperature difference Δ
If it is determined that it is larger than b, it is returned to the original value, and if it is determined that it is smaller than the second temperature difference Δb, the valve opening degree of the electric expansion valve 9 is increased again or the refrigerant temperature target value is set. Is controlled (step 5).

That is, according to this embodiment, when the refrigerant temperature in the refrigeration cycle is detected and the valve opening of the electric expansion valve 9 is controlled according to the detected value, the room temperature approaches a certain set temperature. If you do, you pay attention to the fact that you may reduce your ability.

Referring to FIG. 3, this exemplifies the control at the time of heating, and when the room temperature T ₁ is in the A region and is considerably lower than the set temperature T ₀ in the process of increasing the room temperature (| For T ₀ −T ₁ |> Δa), the valve opening of the electric expansion valve 9 is normally controlled (step 2 in FIG. 2), the room temperature T ₁ is rapidly increased, and the room temperature T ₁ reaches the B range. When (| T
_{For 0-} T ₁ | <Δa), the valve opening of the electric expansion valve 9 is forcibly controlled to be large, the capacity is reduced, and the room temperature T ₁ is slowly increased (step 3).

At the next stage, the room temperature T ₂ is detected,
When the room temperature T ₂ is in the C range and the temperature is extremely close to the set temperature T ₀ (| T ₀ −T ₂ | <Δb), the valve opening degree of the electric expansion valve 9 is further controlled to a large degree. The temperature is decreased to raise the room temperature T _{2 more} slowly (step 5).

As described above, according to this embodiment, the room temperature T ₁ ,
T ₂ is detected step by step, and each room temperature T ₁ , T ₂ and set temperature T
The difference between the _{0 | T 0 -T 1, T} 2 | look, this difference | T ₀ -
T, T ₂ | and a certain temperature difference Δa, Δb (where Δb <Δ
a) is compared, and the valve opening degree of the electric expansion valve 9, for example, is forcibly controlled based on this comparison.

When the room temperature approaches a certain set temperature, the capacity of the room temperature is gradually reduced to the room temperature T ₁ , T _2.
Since the temperature rises slowly, the thermo-OFF state is not maintained for a long time, the thermo-ON and the thermo-OFF are not frequently repeated, the room temperature fluctuation is reduced, and an extremely comfortable air-conditioning state is obtained. In addition, it consumes less power, which makes it extremely economical.

FIG. 4 shows another embodiment. First, the room temperature T ₁ is detected, the absolute value of the difference between this detected value and the set temperature T ₀ is obtained, and this difference | T ₀ −T ₁ | is compared with a certain temperature difference a (step 11), and this difference is calculated. If | T ₀ −T ₁ | is larger than the temperature difference a, the control time interval of the electric expansion valve 9 is maintained constant (for example, every 30 seconds) via the adjusting means 12 as a normal control, and the valve is controlled. The opening is adjusted to an appropriate opening (step 12). And, conversely, the difference | T ₀
If −T ₁ | is smaller than the temperature difference a, the control time interval of the electric expansion valve 9 is lengthened to about 40 seconds, for example, by the correction means 13, and the valve opening degree at that time is adjusted by the adjustment means 12. It is made smaller than the opening (step 13).

Referring to FIG. 5, the dotted line shows the control during heating, and the solid line shows the control during cooling. In the process of heating, when the room temperature T ₁ is in the A region and is considerably lower than the set temperature T ₀ (| T ₀ −T ₁ |> a), the electric expansion is performed. Since the valve opening is controlled to an appropriate opening while keeping the operation time interval of the valve 9 constant, the room temperature T ₁ rises rapidly. After that, when the room temperature T ₁ reaches the region B and is extremely close to the set temperature T ₀ (| T ₀ −T ₁ | <a), the operation time interval of the electric expansion valve 9 is lengthened to adjust the valve opening degree. Since the valve opening degree is smaller than that of 12, the rise of the room temperature T ₁ is gentle.

According to this, as in the above embodiment, since the thermo-OFF state is not maintained for a long time, the thermo-ON and the thermo-OFF are not frequently repeated, the fluctuation of the room temperature is reduced, and the air conditioning is extremely comfortable. The state is obtained.

FIG. 6 shows another embodiment. First, the refrigerant temperature T ₄ during the refrigeration cycle is detected, and the detected value T
₄ and absolute value of difference between refrigerant temperature target value T ₃ | T ₃ −T ₄
|, And the difference | T ₃ −T ₄ | is compared with a preset temperature difference b (step 21). As a result, the difference |
When T ₃ −T ₄ | is larger than the temperature difference b, the operation time interval of the electric expansion valve 9 is maintained constant (for example, every 30 seconds) through the adjusting means 12 as a normal control.
The valve opening is adjusted to an appropriate opening (step 22). On the contrary, if the difference | T ₀ −T ₁ | is smaller than the temperature difference b, the control time interval of the electric expansion valve 9 is lengthened to about 40 seconds, for example, through the correction means 13, and the valve at that time is increased. The opening is made smaller than the valve opening by the adjusting means 12 (step 23).

The control during heating will be described with reference to FIG. 7. When the room temperature T ₁ is in the A region and is considerably lower than the set temperature T ₀ in the process of increasing the room temperature (|
For T ₀ −T ₁ |> a), the operating time interval of the electric expansion valve 9 is kept constant and the valve opening is controlled to an appropriate opening, so that the room temperature T ₁ rises rapidly. is there. Then room temperature T
_{When 1} reaches the region B and approaches the set temperature (target zone) T ₀ extremely (| T ₀ −T ₁ | <a), the electric expansion valve 9
Means for adjusting the valve opening at that time by increasing the operation time interval of
Since the valve opening degree is controlled to be smaller than that of 2, the rise in the room temperature T ₁ is moderate.

Even in this case, since the thermo-OFF state is not maintained for a long time, the thermo-ON and the thermo-OFF are not frequently repeated, the fluctuation of the room temperature is reduced, and an extremely comfortable air-conditioning state can be obtained.

[0028]

As is apparent from the above description, according to the present invention, when the refrigeration load is reduced to a predetermined value or less, that is, when the room temperature approaches a certain set temperature, the valve opening degree of the expansion valve is normally set. Since the capacity is reduced by forcibly increasing the valve opening degree or decreasing the valve opening degree and then increasing the valve opening adjustment interval for a certain period of time, the thermostat does not turn off for a long time. It is not necessary to repeatedly turn ON and thermo OFF frequently, fluctuations in room temperature are reduced, an extremely comfortable air conditioning state can be obtained, and power consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a refrigerating apparatus according to the present invention.

FIG. 2 is likewise a flowchart.

FIG. 3 is a diagram similarly showing control during heating.

FIG. 4 is a flowchart showing another embodiment.

FIG. 5 is a diagram similarly showing control during cooling and heating.

FIG. 6 is a flowchart showing another embodiment.

FIG. 7 is a diagram similarly showing control during heating.

[Explanation of symbols]

 1 Separation type air conditioner 2 Piping between units 3 Indoor heat exchanger 4 Indoor fan 5 Compressor 6 Four-way valve 7 Outdoor heat exchanger 8 Accumulator 9 Electric expansion valve 11 Controller 12 Adjustment means 13 Correction means 16, 17 Temperature sensor

Claims (2)

[Claims] 1. A refrigeration cycle is formed by sequentially connecting a compressor, a condenser, an electric expansion valve, and an evaporator with a refrigerant pipe, and the valve opening degree of the electric expansion valve is based on the refrigerant temperature in the refrigeration cycle. In a refrigerating apparatus having an adjusting means for adjusting the valve opening degree to an appropriate opening degree, the refrigerating apparatus is provided with a correcting means for making the valve opening degree of the electric expansion valve larger than the valve opening degree by the adjusting means when the refrigeration load is reduced to a predetermined value or less. Refrigerating device characterized in that 2. A refrigeration cycle is constructed by sequentially connecting a compressor, a condenser, an electric expansion valve, and an evaporator with a refrigerant pipe, and the valve opening degree of the electric expansion valve is based on the refrigerant temperature in the refrigeration cycle. In a refrigerating device having an adjusting means for adjusting the opening degree to a proper opening degree at a constant time interval, when the refrigerating load is reduced to a predetermined value or less, the adjustment interval of the valve opening degree of the electric expansion valve is made longer than the constant time period, A refrigerating apparatus comprising a correction means for making the valve opening degree at this time smaller than the valve opening degree by the adjusting means.