JPH0264342A - Air conditioner - Google Patents

Abstract

PURPOSE:To enable a refrigerant circuit to be kept in a pressure condition having always excellent efficiency by providing a pressure control means which receives a signal from a pressure sensor to control the number of revolutions of an outdoor fan. CONSTITUTION:A pressure sensor 6 is mounted on the delivery side of a compressor 1, and a pressure control means 7 is provided for deciding by means of a signal from the pressure sensor whether a pressure is higher or lower than a preset proper value and issuing a frequency command to an inverter 9 connected to an outdoor fan 8. LP produces the lower limit of a proper pressure and HP produces the upper limit of a proper pressure, when a delivery pressure P is in a relation of LP <= P <= HP, the pressure control means 7 judges that an air conditioner is run within a proper pressure, and a frequency command to the inverter 9 is not changed. In the case of HP < P, the pressure control means 7 outputs a command by means of which the frequency of the inverter 9 is reduced. Meanwhile, in the case of P < LP, the pressure control means 7 outputs a command by means of which the frequency of the inverter 9 is increased. Thus, a delivery pressure is kept at an always constant value through a change in the number of revolutions of the outdoor fan and a change in an amount of blast to a heat exchanger on the outdoor side.

Description

[Detailed description of the invention] Industrial applications The present invention relates to pressure control for air conditioners.

2. Description of the Related Art As shown in FIG.
03, and a pressure gas isochi 106 that senses the condensation pressure of the refrigerant circuit consisting of a capillary tube 104, a damper 107 that changes the amount of air blown by the outdoor fan 106 that blows air to the outdoor heat exchanger 102, and an indoor fan 10B that blows air into the room. It is configured.

In the above configuration, the air flow rate of the outdoor fan 106 is set assuming high temperatures in summer.
When the condensing pressure falls below the set pressure, such as when the outside temperature is relatively low at night, the opening degree of the damper 104 is reduced to reduce the amount of air blown to the outdoor heat exchanger 102, thereby reducing the condensing pressure. was made to prevent it from dropping too much.

Problems to be Solved by the Invention However, with the above configuration, since the amount of air blown to the outdoor heat exchanger 102 changes in stages, it is difficult to keep the pressure constant regardless of the outside temperature. In extreme cases, the damper 104 could open and close repeatedly, resulting in a pressure hunting state, making it impossible to operate the air conditioner under the most efficient pressure conditions, resulting in a decrease in heating and cooling capacity, and performance. This had the problem of causing a decrease in the coefficient.

The present invention takes into consideration the above-mentioned conventional problems and aims to provide an air conditioner that can always maintain a refrigerant circuit under an efficient pressure condition.

Means for Solving the Problems In order to achieve this object, the present invention provides an indoor fan that blows air to a refrigerant circuit consisting of a compressor, an outdoor heat exchanger, an indoor heat exchanger, and a capillary tube, and an indoor heat exchanger. an outdoor fan that blows air to the outdoor heat exchanger to promote heat exchange; an inverter that makes the rotation speed of the outdoor fan variable; and a pressure sensor that detects the discharge pressure of the compressor;
The air conditioner is configured to include a pressure control means for controlling the rotation speed of the outdoor fan in response to a signal from the pressure sensor.

Effect: With this configuration, the rotation speed of the outdoor fan is changed by the pressure control means in response to a signal from the pressure sensor, and the amount of air blown to the outdoor heat exchanger is changed, so that the discharge pressure is constantly maintained. It will be kept constant.

EXAMPLE An example of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, a compressor 1 for compressing refrigerant;
A refrigerant circuit includes an outdoor heat exchanger 2 connected to the outdoor heat exchanger 2, a capillary tube 3 connected to the outdoor heat exchanger 2, and an indoor heat exchanger 4 connected to the capillary tube 3. On the other hand, an outdoor fan 8 that blows air to the outdoor heat exchanger 2 and an indoor fan 5 that blows air to the indoor heat exchanger 4 are respectively attached. In addition, a pressure sensor 6 is attached to the discharge side of the compressor 1, and based on the signal from this pressure sensor, it is determined whether the pressure is high or low relative to a preset appropriate pressure, and the pressure sensor is connected to an outdoor fan 8. A pressure control means 7 is provided which issues a frequency command to the inverter 9.

The operation of the air conditioner configured as described above will be explained below using FIG. 2.

LP indicates the lower limit of proper pressure, and HP indicates the upper limit of proper pressure. Therefore, if the discharge pressure P is LP≦P≦HP, the pressure control means 7 determines that the air conditioner is being operated within the appropriate pressure, and does not change the frequency command to the inverter 9. When HP is P, the pressure control means 7 determines that the air conditioner is being operated at a pressure higher than the appropriate pressure, and issues a command to increase the 477790 frequency. On the other hand, when P<LP, the pressure control means γ determines that the air conditioner is being operated at a pressure lower than the appropriate pressure, and issues a command to reduce the frequency of the inverter 9. At this time,
If the pressure at time a is HP<P, the frequency of the inverter 9 starts to rise and becomes fixed at time b when P≦Hp. However, due to the drop in outside temperature, etc., the pressure continues to decrease, resulting in P and LP.
At time C, the impark 90 frequency begins to decrease, and at time d, when LP≦P, the frequency of the inverter 9 is fixed.

As described above, according to the above configuration, the discharge pressure is always maintained within a certain range, and the air conditioner can be operated under the most efficient pressure conditions.

Effects of the Invention As is clear from the above description of the embodiments, according to the present invention, by controlling the frequency of the outdoor fan inverter using the discharge pressure of the compressor, the air conditioner can be operated within a certain appropriate pressure range. Because of this, the air conditioner can always be operated under the most efficient pressure conditions, which has the effect of preventing a decrease in heating and cooling capacity and a decrease in the coefficient of performance due to changes in outside air conditions.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an air conditioner according to an embodiment of the present invention;
The figure is an explanatory diagram of the relationship between the discharge pressure and the inverter frequency of the air conditioner, and FIG. 3 is a configuration diagram of a conventional air conditioner. 1...Compressor, 2...Outdoor heat exchanger, 3...Capillary tube, 4...
・Indoor heat exchanger, 6... Indoor fan, 6...
... Pressure sensor, 7 ... Pressure control means, 8 ... Outdoor fan, 9 ... Inverter.

Claims (1)

[Claims] A refrigerant circuit consisting of a compressor, an outdoor heat exchanger, an indoor heat exchanger, and a capillary tube, an indoor fan that blows air to the indoor heat exchanger, and an outdoor fan that blows air to the outdoor heat exchanger to promote heat exchange. , an inverter that makes the rotation speed of the outdoor fan variable, a pressure sensor that detects the discharge pressure of the compressor, and a pressure control means that receives a signal from the pressure sensor and controls the rotation speed of the outdoor fan. Air conditioner.