JPS6314062A - 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 Field of the Invention The present invention relates to an air conditioner equipped with a refrigerant control device.

BACKGROUND ART Conventionally, a heat pump air conditioner equipped with an inverter compressor has a refrigeration cycle as shown in FIG. That is, a compressor ω whose operating frequency is changed and controlled by an inverter, a four-way valve 51, an outdoor heat converter 52, an electric expansion valve 63 whose refrigerant throttling amount is changed by a pulse signal, and this electric expansion valve. A bridge circuit 62 constituted by a reverse valve that makes the flow direction of refrigerant to 63 the same during both cooling and heating, a pipe 63 connecting this bridge circuit 62 and the inlet side of the electric expansion valve 630, and the electric expansion valve 630. A pipe 64 connecting the outlet side of the valve 63 and the bridge circuit 62, an indoor heat exchanger 54, an accumulator 66, a bypass capillary tube 66 that bypasses high-pressure liquid refrigerant to a low pressure, and an inlet side of the electric expansion valve 53. A piping 57 connecting the bypass capillary tube 66, a piping 6o connecting the four-way valve 61 and the accumulator 66, a piping 68 connecting the bypass capillary tube 56 and the piping 60, and the piping. 6o bypass capillary tube 6
A suction temperature thermistor 61 that senses the temperature of the low-pressure gas refrigerant installed before it joins the pipe 68 of e and the pipe 6
a saturated steam temperature thermistor 59 that senses the temperature of the saturated steam refrigerant bypassed through the bypass capillary tube 66 attached to the bypass capillary tube 66; and piping connecting the four-way valve 51 and the indoor heat exchanger 64; A pressure sensor X is connected to detect high-pressure refrigerant during heating and low-pressure refrigerant during cooling.

In such a refrigerant circuit, during heating, the high pressure is sensed by the pressure sensor d, and the frequency is controlled by the inverter so that the high pressure falls within the high pressure range input into the microcomputer in advance.On the other hand, during cooling, the high pressure is sensed by the pressure sensor d. The low pressure is sensed by φ and the frequency is controlled to stay within the determined low pressure range. In addition, during both cooling and heating, the temperature of the saturated vapor refrigerant that bypasses the bypass capillary tube 5e and flows is detected by the saturated vapor temperature thermistor 59, and the temperature of the low pressure gas that has evaporated and passed through the four-way valve 61 is detected by the suction temperature thermistor 61. The electric expansion valve 63 is opened and closed so that the temperature difference between these two temperatures becomes an appropriate degree of superheat.

Problems to be Solved by the Invention With such a conventional configuration, the pressure sensor e cannot detect low pressure during heating operation, so the liquid refrigerant is bypassed from the piping 63 with the capillary tube 66 to lower the temperature of the saturated vapor refrigerant. Originally, the degree of superheating was determined by the saturated steam temperature thermistor 59 and the suction temperature thermistor 61, but in this refrigerant control circuit, the saturated steam temperature thermistor 69 and the suction temperature thermistor 61 both control the refrigerant temperature through steel pipes. Since the temperature is measured, there is inevitably a delay in response to changes in the temperature of the refrigerant, and there are many variations, making it impossible to precisely control the degree of superheating.

In addition, in order to solve the above problems, there was a control method that used two pressure sensors, one on the high pressure side and one on the low pressure side, to constantly monitor the high and low pressures, but the pressure sensor S
Since t+ was extremely expensive, cost reductions were prevented.

The present invention solves these problems, and aims to provide good operational control using a simple and inexpensive refrigerant circuit and control method.

Means to solve problems In order to solve this problem, the present invention provides a compressor.

Equipped with a refrigeration cycle in which an evaporator, an expansion mechanism, a condenser, etc. are connected in sequence, and a high-pressure electromagnetic two-way valve led out and connected to the discharge side piping of the compressor, and led out and connected to the low-pressure side piping. In such a refrigeration circuit, a pressure sensor is provided which is led out from the piping connecting the low-pressure solenoid two-way valve, the high-pressure solenoid two-way valve, and the low-pressure solenoid two-way valve. During heating, when each electromagnetic two-way valve is opened and closed alternately, high pressure and low pressure are sensed alternately by the pressure sensor, frequency control is performed at high pressure, and superheat degree control is performed at low pressure.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in the figure, there is a compressor 1 that is operated by changing the operating frequency using an inverter, a four-way valve 2, an outdoor heat exchanger 3, an electric expansion valve 4 that changes the throttling amount by a pulse signal, and an indoor heat exchanger. 6 and an accumulator 6 are installed in sequence. A low pressure solenoid two-way valve 7 led out from the suction side piping 26 of the compressor 1, a high pressure solenoid two way valve 8 led out from the discharge side piping 26 of the compressor, and the low pressure solenoid two way valve 7. When the low pressure solenoid two-way valve 7 is opened, low pressure is sensed by the connecting pipe 9 connecting the high pressure solenoid two-way valve 8 and the high pressure solenoid two-way valve 8 is opened. A pressure sensor 10 that senses high pressure; a suction temperature thermistor 11 that senses the refrigerant suction temperature in the middle of a pipe 25 provided between the four-way valve 2 and the accumulator 6;
An indoor unit 12 and an outdoor unit 13 are provided.

FIG. 2 shows the control blocks of this control circuit, including a low voltage power supply circuit 14 that supplies a low voltage to the pressure sensor 1o, and A that converts the analog signal of the pressure sensor 1o into a digital signal.
/D converter 16, a temperature detection circuit 16 that detects the temperature sensed by the suction temperature thermistor 11, and the A/D converter 16;
A microcomputer (hereinafter referred to as a microcomputer) 17 that receives signals from the D converter 16 and the temperature detection circuit 16 and performs calculations is provided, and this microcomputer 17 has a switching circuit 18 that performs switching of the giant transistor.
Sends signals to low pressure solenoid two-way valve 7 and high pressure solenoid two-way valve 8
A signal is sent to a relay excitation circuit 2o that turns each electromagnetic two-way valve relay ON-OFF 2, and further signals are sent to a pulse wave oscillation circuit 19 that sends a pulse wave to the coil of the electric expansion valve 4.

In the above configuration, during heating operation, the microcomputer 17 outputs a signal to alternately turn ON and OFF the respective electromagnetic two-way valve relays at certain intervals, and when the high-pressure electromagnetic two-way valve 8 is open, the pressure sensor 10 senses the high pressure in the pipe 26,
Send the analog signal to the A/D converter 16 (V), A
/D converter 16 converts it into a digital signal and sends it to microcomputer 17. A predetermined target high pressure range for heating operation is input to the microcomputer 17.
The operating frequency of the compressor 1 is determined so as to fall within this high pressure range, and a signal is sent to the giant transistor switching circuit 18. Further, when the high pressure solenoid valve 8 is closed and the low pressure solenoid two-way valve 7 is opened, the pressure sensor 10 senses the low pressure in the pipe 26 and sends an analog signal to A.
Send to /D converter 16, A/D converter 1
6 sends a digital signal to the microcomputer 17. Then, the microcomputer 17 controls the suction temperature thermistor 11 so that the degree of superheating at each frequency control during heating is determined in advance.
While monitoring all the signals sent through the temperature detection circuit 16 from I am going.

In this way, the heating operation can always be performed at the appropriate frequency and degree of superheat.

Also, during cooling operation, the low-pressure electromagnetic two-way valve 7 is always open, and the pressure sensor 1o detects the low pressure in the pipe 26, and the microcomputer 17 controls the pressure so that the low pressure falls within a predetermined low pressure range. The frequency is controlled, and the low pressure by the pressure sensor 10 and the suction temperature thermistor 11 provide an appropriate degree of superheat. The electric expansion valve 4 is controlled by the microcomputer 17 in this way.

Effects of the Invention As is clear from the description of the embodiments described above, the present invention alternately opens and closes a low-pressure electromagnetic two-way valve and a high-pressure electromagnetic two-way valve during heating operation, and uses one pressure sensor to detect high pressure and high pressure. Detects both low pressure and
Since the frequency is controlled by high pressure and the degree of superheat is controlled by low pressure and a suction temperature thermistor, it is possible to always operate at the appropriate frequency and fine degree of superheat.
It has many effects such as improving EER, increasing capacity when heating starts, and protecting the compressor from large fluctuations in load. In addition, conventionally, when performing the above control, two pressure sensors had to be used for high pressure and low pressure, but control can be performed with one pressure sensor, resulting in a significant cost reduction.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle diagram of an air conditioner according to an embodiment of the present invention, FIG. 2 is a control block diagram of the refrigeration cycle, and FIG. 3 is a refrigeration cycle diagram of a conventional air conditioner. 1...Compressor, 3...Outdoor heat exchanger,
4... Electric expansion valve, 6... Outdoor heat exchanger, 7... Low pressure solenoid two-way valve, 8...
High pressure solenoid two-way valve, 9...Connecting pipe, 10...
...Pressure sensor. Name of agent: Patent attorney Toshio Nakao and one other person
-1 compression large fD--・7 stones V/T Fig. 3

Claims (1)

[Claims] It is equipped with a refrigeration cycle in which a compressor, an evaporator, an expansion mechanism, a condenser, etc. are connected in sequence, and a high-pressure electromagnetic two-way valve led out and connected to the discharge side piping of the compressor, and a low-pressure side piping connected to the refrigeration cycle. An air conditioner comprising: a low-pressure electromagnetic two-way valve led out and connected; and a pressure sensor led out from a pipe connecting the high-pressure electromagnetic two-way valve and the low-pressure electromagnetic two-way valve.