JPS6231802Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The present invention relates to an air conditioner equipped with a heat pump type refrigeration cycle and capable of cooling and heating operations, and is particularly suitable for operation during heating operation during the intermediate period such as early spring. Concerning improvement of control structure.

[Technical background of the invention and its problems]

Air conditioners equipped with a heat pump type refrigeration cycle and capable of heating and cooling operations are often used. By the way, in intermediate seasons such as early spring, the outside air temperature is low in the early morning and at night, and there is a large difference from the outside air temperature during the day. When performing heating operation at this time, in order to obtain a sufficient heating effect in the early morning or at night, it is necessary to raise the indoor temperature by increasing the set temperature of the indoor thermometer that detects the temperature of the air-conditioned room. However, because the outside air temperature is high during the day, the heating load is small, and if the system is operated normally in the early morning or at night, heating will be excessive. That is, the discharge pressure of the compressor increases, the winding temperature and the refrigerant gas temperature increase, and the lubricating oil deteriorates more quickly. There are problems such as a decrease in the heat exchange rate and impairing the durability of the compressor. Many devices are equipped with a compressor protection device, which stops the compressor when the discharge pressure exceeds a set value and waits for the pressure to naturally drop.

However, since there is no warm air blowing out, the temperature of the air-conditioned room changes rapidly, impairing comfort. Furthermore, since the compressor is repeatedly operated and stopped under overload conditions, there is a drawback that its durability cannot be improved.

[Purpose of invention]

The present invention attempts to provide an air conditioner that protects the compressor, improves its durability, and improves heating comfort by controlling the compressor to adapt to temperature range changes in outside air temperature during heating operation. It is something to do.

[Summary of the idea]

This invention is equipped with a load detection means consisting of a pressure switch that detects the discharge pressure of the compressor, especially in the intermediate period. A control circuit is provided to control the operation of the system.

[Example of idea]

An embodiment of the present invention will be described below based on the drawings. FIG. 1 shows the refrigeration cycle of an air conditioner, where 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is an expansion valve which is a pressure reducing device, and 5 is an indoor heat exchanger. They communicate via a refrigerant pipe P to form a heat pump type refrigeration cycle. An outdoor air blower 6 is arranged opposite to the outdoor heat exchanger 3, and an indoor air blower 7 is arranged opposite to the indoor heat exchanger 5.
will be placed. Further, a pressure switch 8 is provided on the discharge side refrigerant pipe P of the compressor 1, and a temperature sensor 9 is provided on the indoor heat exchanger 5. An operation panel (not shown) that accommodates an indoor thermostat 10 (described later) is attached to the wall of the air-conditioned room R. The indoor thermostat 10, the compressor 1, the pressure switch 8, the temperature sensor 9, and the outdoor blower 6 are electrically connected to a control circuit 11.

Thus, during cooling operation, the refrigerant is guided as shown by the solid line arrow in the figure. That is, the compressor 1 - the four-way valve 2 - the outdoor heat exchanger 3 - the expansion valve 4 - the indoor heat exchanger 5 - the four-way valve 2 - the compressor 1. The refrigerant evaporates in the indoor heat exchanger 5 and takes away the latent heat of evaporation from the air-conditioned room R to perform this cooling action. During heating operation, the refrigerant is guided as shown by the dashed-dotted line arrow in the figure. That is, compressor 1 - four-way valve 2 - indoor heat exchanger 5 -
The order is: expansion valve 4 - outdoor heat exchanger 3 - four-way valve 2 - compressor 1. The refrigerant is condensed in the indoor heat exchanger 5, and the heat of condensation is released into the air-conditioned room R to perform this heating effect.

However, as shown in Figure 2, especially in early spring, the outside temperature is about 5°C or less in the early morning and at night.
During the daytime, the temperature is about 10℃ or higher. (Kanto area) In other words, the outside temperature is clearly divided into early morning/night and daytime temperature zones. Therefore, in a temperature range where the outside temperature is low, the room temperature does not feel comfortable unless the air-conditioned room R is heated above the sensible temperature. When the outside temperature is high, you will feel hot unless you keep the heating temperature low. Therefore, the change in comfortable room temperature with respect to outside temperature is as shown in the figure.

Therefore, during this period, the operation control as shown in FIG. 3 is performed. That is, if early morning and nighttime are set as normal operation, the outside air temperature will be high during the day, so naturally the discharge pressure Pd of the compressor 1 will increase. The pressure switch 8 detects this and the discharge pressure
When Pd reaches a predetermined pressure, for example 27 kg/cm ² G or more, an electric signal is sent to the control circuit 11. Control circuit 1
1 starts accumulating the number of operations of the pressure switch 8, sends an electric signal to the compressor 1 (R ₁ ), and cuts off power to the compressor 1 (R 1 ) for 3 minutes. At the same time, outdoor blower 6
(R ₂ ) sends a signal to stop driving. Therefore, the amount of heat exchanged in the outdoor heat exchanger 3 decreases, and the amount of heat absorbed by the refrigerant decreases. Compressor 1 after 3 minutes
Restart (R ₁ ). This discharge pressure Pd decreases,
Operation is performed according to the heating load. However, as time passes, the outside air temperature rises, and the discharge pressure Pd also rises accordingly. When the pressure switch 8 detects the predetermined pressure again, it outputs a second electrical signal to the control circuit 11. The control circuit 11 outputs an electric signal to the indoor thermostat 10 to slide it through this on-off range by α°. Note that C ₁ indicates the set temperature of the indoor thermostat 10, and C ₂ indicates the set temperature after sliding. Therefore, the operation of the compressor 1 is now controlled by detecting the temperature of the air-conditioned room R by the indoor thermostat 10.
The discharge pressure is in a low range, and operation is performed in accordance with the outside temperature. After this, if the number of operations of the pressure switch 8 is an odd number, the compressor 1 (R ₁ ) is stopped for 3 minutes and the outdoor fan 6 (R ₂ ) is stopped so that the discharge pressure Pd is the predetermined pressure of 24 kg/cm ² The release is continued until G is reached, and at even times (I = 2n), the discharge pressure Pd is adjusted by sliding the indoor thermometer 10's α℃ on-off range.
Release. Therefore, a comfortable room temperature can be obtained relative to the outside temperature, and the compressor 1 can be operated easily.

FIG. 4 shows the ideal suction temperature range of the indoor heat exchanger 5 with respect to changes in outside air temperature and changes in discharge pressure. The operating value of pressure switch 8 at this time is 27Kg/
cm ² G.

[Effect of idea]

This invention idealizes heating operation during intermediate periods such as early spring, provides comfort, prevents compressor overload operation under any conditions, and significantly improves durability. be effective.

[Brief explanation of the drawing]

Fig. 1 is a piping and electrical system diagram of an air conditioner showing an embodiment of the present invention, Fig. 2 is an ideal heating characteristic diagram in the intermediate period, and Fig. 3 is a flowchart showing compressor operation control by load detection means. The chart diagram, FIG. 4, is a diagram of intake air temperature characteristics. 1...Compressor, 10...Indoor thermostat, 8...Pressure switch, 11...Control circuit.

Claims (1)

[Scope of utility model registration request] In a device equipped with a heat pump type refrigeration cycle and an indoor thermostat that detects the temperature of the air-conditioned room, a load detection means consisting of a pressure switch that detects the discharge pressure of the compressor as the outside air temperature fluctuates during heating operation. An air conditioner comprising: a control circuit that receives a detection signal from the load detection means and slides the detection area of the indoor thermostat to control the operation of the compressor.