JPS61272554A - Air conditioner - 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 [Technical Field of the Invention] The present invention relates to an air conditioner equipped with a variable capacity compressor.

[Technical background of the invention and its problems]

Generally, an air conditioner is equipped with a variable capacity compressor and an inverter circuit that supplies driving power to the variable capacity compressor, and the output frequency of this inverter circuit (hereinafter referred to as the operating frequency) is By changing it according to the load, we can obtain the optimal capacity to handle the air conditioning load.
Some are designed to improve comfort and energy saving effects.

By the way, in such an air conditioner, during heating operation, the temperature (hereinafter referred to as heat exchanger temperature) Tc of the indoor heat exchanger (condenser) corresponding to the high pressure side pressure is detected, and the third
As shown in the figure, once the heat exchanger temperature Tc exceeds the set value Tx, the operating frequency of the compressor is reduced to suppress the increase in pressure on the high pressure side. Thereafter, the heat exchanger temperature T is adjusted at predetermined intervals.
c is compared with the set values Tx and Ty, and if the heat exchanger temperature TO is still higher than the set value Tx even after the reduction in the operating frequency, the operating frequency is further reduced, and the set value Tx,
If it is between Ty, the operating frequency is maintained as it is. However, when the heat exchanger temperature Tc becomes lower than the set value Ty due to such TO release control, the operating frequency is changed to the set value Ty when the heat exchanger temperature Tc is initially
The state is returned to the state at the time when x was exceeded.

However, in this case, in order to suddenly restore the operating frequency, the pressure on the high pressure side rises abnormally, causing the high pressure switch to operate, resulting in an unnecessary shutdown of the operation. Furthermore, since the increase in the pressure on the high pressure side causes the temperature of the air blown into the room to rise, the indoor temperature thermostat is frequently turned off, increasing the number of interruptions in operation. Such unnecessary shutdowns and interruptions result in a decrease in heating efficiency and a decrease in reliability.

[Purpose of the invention]

This invention was made in view of the above circumstances,
The objective is to provide an air conditioner that can reliably suppress increases in pressure on the high pressure side, thereby preventing unnecessary shutdowns and interruptions, and improving heating efficiency and reliability. There is a particular thing.

[Summary of the invention]

This invention provides a heat exchanger temperature sensor that detects the temperature of an indoor heat exchanger, and during heating operation, if the temperature detected by the heat exchanger temperature sensor exceeds a set value Tx, the capacity of the compressor is reduced regardless of the air conditioning load. At the same time, when the temperature detected by the heat exchanger temperature sensor becomes lower than the set value Ty due to this capacity reduction, the pressure II
It gradually increases I's abilities.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 2, 1 is a variable capacity compressor, and this compression el
11, a four-way valve 2, an off-campus heat exchanger 3, a pressure reducing device such as an expansion valve 4, an indoor heat exchanger 5, etc. are connected in sequence to form a heat pump type refrigeration cycle. That is, during cooling operation, the refrigerant flows in the direction of the solid line arrow shown in the figure, forming a cooling cycle, and during heating operation, the four-way valve 2 is switched, so that the refrigerant flows in the direction of the broken line arrow, forming a heating cycle. Ru. A high pressure switch 6 is attached to the refrigerant discharge side piping of the compressor 1.

Furthermore, a heat exchanger temperature sensor 7 is attached to the indoor heat exchanger 5.

On the other hand, 8 is a main control section consisting of a microcomputer and its peripheral circuits, and the heat exchanger temperature sensor 7, indoor temperature sensor 9, operation control section 10, etc. are connected to this main control section. 11 is a frequency variable device (inverter) which receives commands from the main control section 8 and a high voltage switch 6.
The operating frequency of the compression R1 is controlled according to the operating state of the compressor R1.

Next, the operation of the above configuration will be explained with reference to FIG.

The operation unit 10 is used to set the heating operation, set the indoor temperature, and perform the operation start operation.

Then, the main tllII 11 section B determines the rotation speed of the drive motor of the compressor 1 (hereinafter referred to as compressor motor) according to the difference between the indoor temperature Ta detected by the indoor temperature sensor 9 and the set temperature Ts. Then, the output frequency of the frequency variable device 11 is increased in order to increase the rotation speed of the compressor motor at an increase rate R1 toward the determined rotation speed. As a result, the compressor 1 is started. Roughly speaking, the four-way valve 2 switches to form a heating cycle. In this way, heating operation is started by the condensing action of the indoor heat exchanger 3.

When the indoor temperature Ta rises due to heating operation and the heat exchanger temperature TC exceeds the set value Tx, the main control unit 8 adjusts the compression 'es1 regardless of the air conditioning load (the difference between the indoor temperature Ta and the set temperature TS). The operating frequency is reduced and so-called TC release control is started. Then, the heat exchanger temperature Tc and the set value Tx are determined every fixed time t1.

Ty is compared, and if the heat exchanger temperature TO is still equal to or higher than the set values T and X, the operating frequency is further reduced. Also,
When the heat exchanger temperature Tc reaches between the set values Tx and ``ry'', the operating frequency is maintained as it is.

When the heat exchanger temperature Tc becomes lower than the set value Ty due to a decrease in the indoor temperature Ta based on the Tc release tiIl'@, the main control section 8 starts the operation to increase the drive motor of the compressor 1 at an increase rate Rs. Layer - Gradually increase the wave number. In this case, compressor 1. Although the capacity of the room will gradually increase, the indoor temperature Ta is sufficiently close to the set temperature, so there will be no shortage of heating. After a certain period of time t2 (≧11>), if the heat exchanger temperature Tc is at the set value Tx and the indoor temperature Ta is below the set hot water temperature Ts, the operating frequency is gradually increased in the same way. The operating frequency is increased to the same value as at the start of the TC release.However, if this increase causes the heat exchanger temperature Tc to exceed the set value Tx again, the above Tc
Perform release control again.

In this way, when the heat exchanger temperature TC falls below the set value Ty due to the Tc release control, the operating frequency of the compressor 1 is gradually increased, making it possible to prevent abnormal increases in the pressure on the high pressure side. Therefore, unnecessary shutdowns caused by high-pressure switches can be prevented. In addition, since it is possible to suppress the increase in pressure on the high pressure side, it is possible to prevent unnecessary increases in the temperature of the air blown into the room and prevent the indoor temperature thermostat from turning off frequently, thereby reducing the number of interruptions in operation. . That is, since such unnecessary shutdowns and interruptions can be prevented, heating efficiency and reliability can be improved.

In the above embodiment, the rate of increase in the rotation speed of the compressor motor after the heat exchanger temperature Tc becomes equal to or less than the set value Ty is set to R1, which is the same as that at the start of operation, but it may be set to a value smaller than R1. In addition, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without changing the gist.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to reliably suppress the increase in pressure on the high pressure side, thereby preventing unnecessary stoppages and interruptions of operation, and improving heating efficiency and reliability of the air conditioner. We can provide equipment.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the operation in one embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a refrigeration cycle and a control circuit in the same embodiment, and FIG. FIG. 3 is a diagram for explaining Tc release control in the machine. 1... Variable capacity compressor, 2... Four-way valve, 3... Outdoor heat exchanger, 4... Expansion valve, 5... Indoor heat exchanger,
7... Heat exchanger temperature sensor, 8... Main control section, 9...
Indoor temperature sensor. Applicant's agent Patent attorney Takehiko Suzue, 14 years old - Figure 1

Claims (1)

[Claims] In an air conditioner comprising a heat pump type refrigeration cycle in which a variable capacity compressor, a four-way valve, an outdoor heat exchanger, a pressure reduction device, an indoor heat exchanger, etc. are connected in sequence, and the capacity of the compressor is controlled according to the load. , a heat exchanger temperature sensor that detects the temperature of the indoor heat exchanger, and means for reducing the capacity of the compressor regardless of the air conditioning load when the temperature detected by the heat exchanger temperature sensor exceeds a set value Tx during heating operation. As a result of this capacity reduction, the detected temperature of the heat exchanger temperature sensor becomes the set value Ty.
An air conditioner characterized by comprising means for gradually increasing the capacity of the compressor when the capacity of the compressor becomes below.