JPH09184662A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent comfortableness from being deteriorated by determining whether opening of a refrigerant control valve is effective of closing of the valve is effective when a specified high pressure is detected during heating operation. SOLUTION: When a specified high pressure is detected by a pressure sensor 1 and a judgment that selection of high load relieving method is necessary is made, refrigerant pressure discharged from a compressor 51 is stored as a high pressure PH in RAM. Then, a refrigerant control valve 55 of each of indoor units in operation is made to travel to half of a present ratio of the valve opening and a timer function starts counting time. When time counted up exceeds a specified value or pressure difference between the high pressure PH and a current pressure (P) exceeds a specified value, the pressure (P) is compared with the high pressure PH at a next step. If the pressure (P) is lower than the high pressure PH, the refrigerant control valve 55 is made to travel to decrease the ratio of the valve opening, and if the pressure (P) is higher than the high pressure PH, the refrigerant control valve 55 is made to travel to increase the ratio of the valve opening. Thus, an optimum high load relieving method can be selected for each of combinations of the operating indoor units.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner that constitutes a refrigeration cycle by repeating compression / expansion of a refrigerant and performs cooling / heating or the like.

[0002]

2. Description of the Related Art In the case of a so-called multi-type air conditioner in which a plurality of indoor units are connected to one outdoor unit, depending on the number of operating indoor units, the capacity of the outdoor unit and the operating capacity of the indoor unit may differ. The difference may widen.

At present, the capacity of each indoor unit tends to be smaller, and the capacity ratio of the indoor unit to the outdoor unit is 1 :.
There are things like 20. Therefore, during the heating operation in which the refrigerant compressed by the compressor is directly supplied to the indoor unit, the pressure on the discharge side of the compressor is abnormally increased, which is a situation in which a so-called high load state is likely to occur.

If the operation under a high load continues, the temperature of blown air in the indoor unit rises and the comfort is deteriorated. Therefore, the opening of the refrigerant control valve for controlling the amount of the refrigerant flowing into the indoor unit is increased, The amount of condensation is increased to eliminate the high load condition.

[0005]

However, in the above method, the capacity of the indoor heat exchanger that functions as a condenser is smaller than the capacity of the outdoor heat exchanger that functions as an evaporator, for example, 100% or less and 75% or less. It is effective in the above cases, but when the capacity of the indoor heat exchanger is larger than the capacity of the outdoor heat exchanger, although the high load can be eliminated itself, the amount of heat released from the indoor unit increases, so it is practical Is not a good method. That is, there is a problem that opening the refrigerant control valve raises the temperature of the indoor unit and impairs comfort, which is not preferable, and there is a problem to be solved.

[0006]

SUMMARY OF THE INVENTION The present invention is an air conditioner constructed by connecting a compressor, an outdoor heat exchanger, an indoor heat exchanger, etc. by piping as described above.

Pressure detecting means for detecting the refrigerant pressure on the discharge side of the compressor, and refrigerant control for controlling the amount of refrigerant supplied to the indoor heat exchanger when the pressure detecting means detects a predetermined high pressure during heating operation. Judgment control means for determining whether controlling the valve in the opening direction is effective in eliminating high pressure on the compressor discharge side, or controlling in the closing direction of the refrigerant control valve is effective in eliminating high pressure on the compressor discharge side And an air conditioner having a first configuration including:

In the air conditioner of the first construction, when a plurality of indoor heat exchangers are installed and the same indoor heat exchanger as in the previous determination is operating and the pressure detecting means detects a predetermined high pressure, An air conditioner having a second configuration in which the determination control means has a function of substituting the previous determination;

In the air conditioner of the first or second construction, there is provided temperature detecting means for detecting the temperature of the refrigerant flowing out of the indoor heat exchanger during the heating operation, and the pressure detecting means provides a predetermined high pressure during the heating operation. When it is detected, the supercooling degree is calculated based on the data detected by the temperature detecting means and the pressure detecting means, and the opening degree of the refrigerant control valve is effective for canceling the high pressure based on the supercooling degree. By providing the air conditioner of the third configuration in which the determination control means has the function of changing to the determined direction,
The above-mentioned problems can be solved.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 4 is a diagram showing the configuration of an engine-driven heat pump air conditioner, in which 51 is a compressor driven by an engine (not shown), 52 is a four-way valve,
53 is an outdoor heat exchanger, 54 is a receiver tank, 55 is a refrigerant control valve, 56 is an indoor heat exchanger, 57 is an accumulator, and 58 is an expansion valve. These devices are not particularly different from those conventionally known, The heating circuit shown by a broken line and the cooling circuit shown by a solid line are sequentially connected.

The pressure sensor 1 for detecting the pressure of the refrigerant discharged from the compressor 51 and the indoor heat exchanger 5 during the heating operation.
A temperature sensor 2 for detecting the temperature of the refrigerant flowing out of 6,
The controller 3 is installed. In addition, 59 is an outdoor blower, 60
Is an indoor blower, and the indoor blower 60 and the above-mentioned refrigerant control valve 55 and indoor heat exchanger 56 are installed in a room where air conditioning is performed, and are therefore collectively referred to as an indoor unit.

As the controller 3, for example, as shown in FIG. 5, a central processing unit (hereinafter referred to as CPU) 3B is provided by converting the information output from the pressure sensor 1 and the temperature sensor 2 into a signal.
The input interface 3A to output to, a storage device (hereinafter referred to as ROM) 3C that stores a predetermined arithmetic expression, an arithmetic program, and the like, and a signal from the CPU 3B are input to send a required signal to the refrigerant control valve 55 and the like. An output interface 3D for outputting, a clock circuit 3E having a timer function capable of outputting a signal at predetermined time intervals and measuring the required time,
A readable / erasable storage device (hereinafter referred to as RAM) 3F that stores information input from the pressure sensor 1 and the temperature sensor 2 and the time measured by the clock circuit 3E is used.

The ROM 3C has a pressure sensor 1.
Based on the pressure and temperature information of the refrigerant circuit input from the temperature sensor 2, a control program for controlling the opening of the refrigerant control valve 55, for example, shown in FIGS. 1 to 3 is stored.

First, the procedure for selecting the high load elimination method will be described with reference to FIGS. 1 and 2. When the normal operation control based on the air conditioning load is performed by the main control, the pressure sensor 1 detects a predetermined pressure, for example, 2.3 MPa or more, and it is determined that the high load elimination method needs to be selected,
The control flow of FIG. 1 is started, and in step S1, the refrigerant discharge pressure detected by the pressure sensor 1 is set to the high pressure P _H and the RAM 3
Store in F.

In step S2, the opening of the refrigerant control valve 55 of all the operating indoor units is reduced to 1/2 of the current opening.

In step S3, the timer function of the clock circuit 3E is activated to start counting, and in step S4, it is determined whether or not the time T1 measured by the timer function activated in step S3 exceeds a predetermined time, for example, 1 minute. Is determined, and if it exceeds, the process proceeds to step S6, and if not, the process proceeds to step S5.

In step S5, the high pressure P _H stored in the RAM 3F is compared with the refrigerant pressure P currently detected by the pressure sensor 1, and when the pressure difference exceeds 0.1 MPa, step S6. If not, the process returns to step S4.

In step S6, the high pressure P _H and the pressure P are compared. When the current pressure P is lower than the high pressure P _H stored in the RAM 3F, the process proceeds to step S7 and the opening of the refrigerant control valve 55 is closed. When the current pressure P is higher than the high pressure P _H stored in the RAM 3F, the process proceeds to step S8 to select the system control for opening the opening of the refrigerant control valve 55.

Then, in step S9, the opening degree of the refrigerant control valve 55 of all the operating indoor units is doubled to the present opening degree and returned to the original state, and the main control is restored.

Further, the normal operation control based on the air conditioning load is performed by the main control, and the pressure sensor 1 is set to a predetermined pressure,
For example, when 2.3 MPa or more is detected, the control flow of FIG. 2 is started, and in step S21, the operating indoor unit is checked to eliminate the high pressure on the discharge side of the compressor 51 and the refrigerant control valve 55.
When the indoor unit is operating exactly the same as when the previous determination was made as to whether it is effective to control the opening degree of the valve in the opening direction or to control it in the closing direction, the process proceeds to step S22 and the same valve control as the previous time is performed. A system is selected and it returns to main control, and when that is not right, it transfers to step S23, it decides to newly select the method which controls the refrigerant control valve 55, and returns to main control (via step S23 main When returning to the control, the above-described control of FIG. 1 is subsequently performed).

Next, with reference to FIG. 3, a specific control example of the refrigerant control valve 55 executed to eliminate the high pressure will be described.
The normal operation control based on the air conditioning load is performed by the main control, and the pressure sensor 1 has a predetermined pressure, for example, 2.3 MPa.
When the above is detected, and the high voltage cancellation is required, the control flow of FIG. 3 is automatically started, and the high load cancellation method is selected in step S41. In this case, for example, FIG.
Execute in order.

In step S41, the refrigerant control valve 55
When the method of opening the opening of is selected, step S4
After shifting to 2, the opening degree of the refrigerant control valve 55 of all the operating indoor units is fully opened, and then the process returns to the main control. On the other hand, when the method of closing the opening degree of the refrigerant control valve 55 is selected in step S41, the process proceeds to step S43 and the pressure of the refrigerant detected by the pressure sensor 1 is stored in the RAM 3F.

In step S44, the pressure stored in the RAM 3F and the arithmetic expression stored in the ROM 3C are used to calculate
The saturation temperature of the refrigerant discharged from the compressor 51 is calculated.

In step S45, all the temperatures of the refrigerant detected by the temperature sensors 2 of all the operating indoor units are stored in the RAM3.
Store in F.

In step S46, the degree of supercooling (SCi) of each indoor unit is calculated as SCi = saturation temperature-refrigerant outlet temperature of each indoor unit (temperature detected by the temperature sensor 2), and R
Store in AM3F.

In step S47, the degree of supercooling (SCi) of each indoor unit is stored in the RAM 3F as SCi = SCi + 1.

In step S48, the timer function of the clock circuit 3E is activated to start clocking, and in step S49,
Time measured T by the timer function started in step S48
It is determined whether or not 2 exceeds a predetermined time, for example, 10 seconds, and after waiting for the time, the process proceeds to step S50.

In step S50, the degree of supercooling (SC) of each indoor unit (SC) is performed as in steps S43 to S46.
i ′) is calculated as SCi ′ = saturation temperature−refrigerant outlet temperature of each indoor unit and stored in the RAM 3F.

In step S51, the degree of supercooling (SCi) obtained in step S47 and the degree of supercooling (SCi ') obtained in step S50 are sequentially compared across all operating indoor units, and SCi- When SCi 'exceeds 0, the process proceeds to step S52, the opening degree of the refrigerant control valve 55 is reduced by 1 from the present, and the process returns to step S50.
When SCi 'is less than 0, the process proceeds to step S53,
The opening degree of the refrigerant control valve 55 is increased by 1 from the present value and the process returns to step S50. When SCi-SCi 'is 0 (over all indoor units), the process returns to the main control.

As described above, in the air conditioner of the present invention, when the pressure sensor 1 detects a predetermined high pressure, the refrigerant control valve 55 of the operating indoor unit is throttled to change its pressure. By checking, is it more effective to open the refrigerant control valve 55 to eliminate the high pressure (high load state)?
It is determined whether closing is effective, and the opening of the refrigerant control valve 55 of the indoor unit is controlled based on this determination. Therefore, the refrigerant is stored in the operating indoor unit to reduce the amount of circulating refrigerant. Even when the indoor unit having a sufficiently large capacity that the heating (condensing) capacity does not decrease is operating, the refrigerant control valve 55
To reduce the high load condition,

On the contrary, if the capacity of the operating indoor unit is small and the refrigerant control valve 55 is throttled to store the refrigerant in the indoor unit, the heating (condensing) capacity is lowered and the pressure is further increased. When rising, the optimum high load elimination method can be selected for each combination of operating indoor units, such as opening the opening of the refrigerant control valve 55 to eliminate the high load condition.

Since the present invention is not limited to the above-mentioned embodiment, various modifications can be made within the scope of the claims.

For example, the operation of step S2 in FIG.
It is also possible to configure so as to perform only for an appropriate number such as three or half.

Further, the operation of step S2 in FIG. 1 may be configured so that the opening degree of the refrigerant control valve 55 is increased, for example, by 20%, and the subsequent pressure change is examined. In this case, the inequality sign in the determination expression in step S6 is reversed.

[0035]

As described above, in the air conditioner of the present invention, when the pressure detecting means detects a predetermined high pressure,
Is it more effective to open the refrigerant control valve to eliminate the high load state by checking the pressure change by squeezing the opening of the refrigerant control valve of the operating indoor unit to, for example, 1/2?
It is determined whether it is effective to close it, and the opening of the refrigerant control valve of the indoor unit is controlled based on this determination, so even if the amount of circulating refrigerant is reduced by storing the refrigerant in the operating indoor unit. When an indoor unit with a sufficiently large capacity that the heating (condensing) capacity does not decrease is operating, the opening of the refrigerant control valve is reduced to eliminate the high load state,

On the contrary, if the capacity of the operating indoor unit is small and the refrigerant control valve is throttled to store the refrigerant in the indoor unit, the heating (condensing) capacity is lowered and the refrigerant pressure is further increased. When rising, it is possible to select the optimum high load elimination method for each combination of operating indoor units, such as opening the opening of the refrigerant control valve to eliminate the high load condition.

In order to eliminate the high load condition, the completely same indoor unit is operated as when it was previously determined whether it is effective to control the opening of the refrigerant control valve in the opening direction or to control it in the closing direction. In the air conditioner configured to select the same valve control method as the previous time, the high load state can be quickly eliminated.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a selection procedure of a high load elimination method.

FIG. 2 is an explanatory diagram showing a selection procedure of a high load elimination method.

FIG. 3 is an explanatory diagram showing a high load elimination procedure.

FIG. 4 is an explanatory diagram showing the overall configuration of the apparatus.

FIG. 5 is an explanatory diagram showing a configuration of a controller.

[Explanation of symbols]

 1 Pressure Sensor 2 Temperature Sensor 3 Controller 3A Input Interface 3B Central Processing Unit (CPU) 3C Storage Device (ROM) 3D Output Interface 3E Clock Circuit 3F Storage Device (RAM) 51 Compressor 52 Four-way Valve 53 Outdoor Heat Exchanger 54 Receiver tank 55 Refrigerant control valve 56 Indoor heat exchanger 57 Accumulator 58 Expansion valve 59 Outdoor blower 60 Indoor blower

Claims (3)

[Claims] 1. An air conditioner configured by connecting a compressor, an outdoor heat exchanger, an indoor heat exchanger, and the like by piping, the pressure detecting means for detecting the refrigerant pressure on the discharge side of the compressor, and the pressure detecting means. When a predetermined high pressure is detected during the heating operation, it is effective to eliminate the high pressure on the discharge side of the compressor by controlling the direction in which the refrigerant control valve that controls the amount of the refrigerant supplied to the indoor heat exchanger is opened, or the refrigerant. An air conditioner, comprising: a determination control unit that determines whether controlling the control valve in a closing direction is effective in eliminating high pressure on the discharge side of the compressor. 2. A plurality of indoor heat exchangers are installed, and
The air conditioner according to claim 1, wherein the determination control means has a function of substituting the previous determination when the same indoor heat exchanger as in the previous determination is operating and the pressure detection means detects a predetermined high pressure. 3. A temperature detecting means for detecting the temperature of the refrigerant flowing out of the indoor heat exchanger during the heating operation, and when the pressure detecting means detects a predetermined high pressure during the heating operation, the temperature detecting means and the pressure detection. Determination control means for calculating the degree of supercooling based on the data detected by the means, and changing the degree of opening of the refrigerant control valve based on the degree of supercooling to a direction determined to be effective for eliminating the high pressure. The air conditioner according to claim 1 or 2, which is provided with.