JPH0357380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a load detection configuration for determining the compressor operating frequency of a multi-chamber heat pump air conditioner.

Conventional configuration and its problems Conventionally, in multi-room air conditioners in which multiple indoor units are connected to one outdoor unit, a compressor is installed in the outdoor unit, and this compressor operates at a constant speed. Either the motor is operated with the rotation of The former one with constant speed is
Since the capacity of the compressor itself does not change, the input does not change depending on the number of units in multi-room operation, and when operating with a small number of indoor units, it changes due to factors such as bypassing excess refrigerant circulation, so EER (consumption efficiency) ) has the disadvantage of becoming worse. Also, the latter method using pole number conversion is 4
It has a two-stage switching system from pole operation to two-pole operation, and has better EER than a constant speed type because the input can be reduced to about half when a small number of machines are in operation.
As shown in Figures 1 and 2, this pole number conversion method is based on the discharge pressure during heating (Figure 1) and the discharge pressure during cooling (Figure 2).
The suction pressure shown in the figure) is detected by a pressure switch, and the pressure is switched from 2 poles to 4 poles and from 4 poles to 2 poles after a certain pressure is reached. However, with this method, the capacity change is approximately twice that between 2-pole and 4-pole, and in the middle, for example, at 75% load, the 2-pole and 4-pole
It has to be operated with either poles or four poles, resulting in insufficient or excessive capacity, and has the disadvantage that it cannot respond accurately to the load no matter which way it is operated.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and provides a more accurate load detection configuration for determining the compressor operating frequency in a compressor that performs inverter control such as frequency change. With the goal.

Structure of the Invention The invention includes a bellows or a diaphragm, and a conversion element that detects the displacement of the bellows or diaphragm and converts it into an electric signal, and controls the compressor via an electric signal converter that converts pressure electrically. The bellows is connected to the refrigeration cycle through a thin tube to detect the discharge pressure during heating and to detect the suction pipe pressure during cooling.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 3 to 5.

In one outdoor unit, 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is a heating expansion valve, 5
is a check valve for cooling operation, 6 is a liquid receiver, 7 is a three-way valve on the liquid side, 8 and 9 are liquid side solenoid valves, 10 and 11 are expansion valves for cooling, and 12 and 13 are check valves for heating operation. valve, 14,1
5 is an indoor heat exchanger, 16 and 17 are gas side solenoid valves,
18 is the gas side three-way valve, 19 is the storage regulator,
Reference numeral 20 denotes a bellows housing, in which a bellows 21 is provided, and on one side of the connecting pipe 22, a heating thin pipe 2 is installed.
2a, and a solenoid valve 23 that opens during heating.
A pipe 24 is provided, the end of which becomes under high pressure during heating.
is connected to. Further, on the other side of the connecting pipe 22, a cooling thin pipe 22b and a solenoid valve 25 for cooling time are provided in the middle thereof, and the end thereof is connected to the suction pipe 26 which becomes low pressure during cooling (same as during heating). There is. In the bellows 21, 27 is a permanent magnet attached to the bellows 21, and 28 is a magnetoresistive conversion element, which is installed on a printed circuit board 29 equipped with electronic control. simultaneously moves left and right, and at that time, the resistance value changes in the magnetoresistive conversion element 28, which is calculated on the printed circuit board 29 and converted into an electrical signal. A lead wire 30 is connected to an electric signal converter 31, and the electric signal converter 31 controls the frequency conversion of the compressor 1 (FIG. 3) using an inverter.

In the above configuration, during heating operation, when the heating load increases, the discharge pressure tends to decrease, and when the heating load decreases, the discharge pressure tends to increase; during cooling operation, when the cooling load increases, the suction pressure increases,
As the cooling load decreases, the suction pressure tends to decrease. Therefore, during heating, the solenoid valve 23 is kept open, and the heating thin tube 22a is connected to the pipe 24 which becomes a discharge pipe during heating, so that the pressure depending on the magnitude of the load during heating can be continuously detected. The bellows 21 expands and contracts, and the movement of the permanent magnet 27 changes the resistance value of the magnetoresistive conversion element 28, and the electrical signal converter 31 causes the pressure to fall within a certain range as shown in FIG. 4 during heating. It is possible to control the compressive force so that the compressive force is controlled and extract the compressive force corresponding to the load. This also applies during cooling; the solenoid valve 25 is left open during cooling, and the cooling thin tube 22b is connected to the suction pipe 26, so the pressure in the suction pipe depends on the load during cooling. By continuously detecting the bellows 21
expands and contracts, and the movement of the permanent magnet 27 changes the resistance value of the magnetoresistive conversion element 28, and the electric signal converter 31 adjusts the pressure to within a certain range as shown in FIG. 5 during cooling. In addition, it is possible to control the compression force and extract the compression force corresponding to the load. That is, bellows 21, permanent magnet 2
7. The magnetoresistive conversion element 28 is a pressure sensor that converts changes in discharge pressure during heating and changes in suction pressure during cooling into continuous electrical signal changes. As shown in Figures 4 and 5,
The compressor is controlled over a wide range to achieve optimal load operation.

Effects of the Invention As described above, the present invention provides a bellows that detects discharge pressure during heating and detects suction pipe pressure during cooling;
A permanent magnet is attached to this bellows, and a magnetoresistance conversion element is provided near the permanent magnet to continuously detect the discharge pressure during heating and the suction pipe pressure during cooling. Since the compressor is controlled by an inverter over a wide range of frequency conversion, the inverter's capacity can be continuously varied by detecting only the outdoor unit in an outdoor unit connected to multiple indoor units. The feature is fully demonstrated, and the cycle corresponding to the load is stable during both the refrigeration cycle (cooling) and the heat pump cycle (heating), especially in multi-room refrigerant circulation that tends to be unstable. Moreover, it can be operated economically and exhibits excellent effects.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams for switching the number of poles during heating and cooling in a conventional multi-chamber heat pump type air conditioner, and Figure 3 is a multi-chamber heat pump type air conditioner that is an embodiment of the present invention. The schematic diagram of the configuration of the air conditioner, FIGS. 4 and 5, are explanatory diagrams of changes in the inverter frequency during heating and cooling of the air conditioner. 21... Bellows, 27... Permanent magnet, 28...
...Magnetoresistive conversion element.

Claims (1)

[Claims] 1 A bellows or diaphragm that detects discharge pressure during heating and suction pressure during cooling,
A permanent magnet is attached to this bellows, and the bellows is
Alternatively, when the diaphragm expands and contracts due to pressure, the permanent magnet also moves at the same time, and a magnetoresistive conversion element that detects the amount of displacement due to the expansion and contraction and converts it into an electric signal on a printed circuit board corresponding to the permanent magnet. A multi-chamber heat pump that continuously detects the discharge pressure during heating and the suction pressure during cooling, and controls the compressor by inverter frequency conversion using an electric signal converter connected to the printed circuit board. type air conditioner.