JPH0454865B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a refrigerating capacity control device for a refrigerator, and particularly to measures for improving the refrigerating capacity at high outside temperatures.

(Prior art) In general, in a refrigerator equipped with an air-cooled condenser, when the outside temperature rises, the cooling state of the refrigerant deteriorates due to a decrease in heat dissipation in the air-cooled condenser, causing the condensing pressure to rise. As the temperature increases, the refrigeration capacity tends to decrease.

For this reason, conventionally, for example, the compressor disclosed in Japanese Utility Model Publication No. 57-54526 uses a variable capacity compressor,
A capacity control means for controlling the capacity of the compressor according to the refrigeration load, a water spray nozzle for spraying water to the air-cooled condenser, and a detector for detecting the outside air temperature and the condensation pressure of the air-cooled condenser, If the compressor is at its maximum capacity when the outside temperature rises, water is sprayed from the water nozzle into the air-cooled condenser to lower the condensing pressure and increase the condensing capacity, increasing the refrigeration capacity above the maximum capacity of the compressor. I am trying to increase it.

(Problem to be Solved by the Invention) However, in the conventional system described above, when the compressor is at its maximum capacity at high outside temperatures, the water spray nozzle is always activated and water is sprayed into the air-cooled condenser. However, when the load is light and the temperature to be controlled, such as room temperature, is within the control range, the increase in refrigeration capacity may cause the temperature to be controlled to drop beyond the control range, resulting in overfreezing. It was hot.

The present invention has been made in view of the above, and its purpose is to provide a refrigerator equipped with a variable capacity compressor and a water spray nozzle as described above, when the compressor is at its maximum capacity when the outside temperature is high. By controlling the operation/stop of the water spray nozzle according to the refrigeration load, if the temperature to be controlled is not within the control range, the refrigeration capacity is increased by sprinkling water to the air-cooled condenser, and the temperature to be controlled is While approaching the target value,
When the temperature of the controlled object is within the control range, the operation of the water spray nozzle is stopped, the temperature of the controlled object is maintained within the controlled range, and the convergence to the target value is improved.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention includes a variable capacity compressor 2, as shown in FIG.
2', and capacity control means 60 for controlling the capacity of the compressors 2, 2' according to the refrigeration load,
a water spraying means 50 for spraying water on the air-cooled condenser 1; an overload detection means TH _B for detecting overload; a maximum detection means 61 for detecting the maximum capacity of the compressors 2 and 2'; In-range detection means 62 is provided for detecting when the target temperature is within the control range. In response to the outputs of the respective detection means TH _B , 61, and 62, when the capacity of the compressors 2 and 2' is at maximum in an overload state, if the temperature to be controlled is not within the control range, air-cooled condensation is performed. It is configured to include a water sprinkling control means 63 for operating the water sprinkling means 50 to spray water onto the container 1.

(Function) With the above configuration, in the present invention, when the capacity of the compressors 2, 2' is at the maximum at the time of overload, the water sprinkling means 50 is controlled to operate/stop according to the refrigeration load, and the temperature to be controlled is controlled. If the condensing pressure is not within the control range, the condensing pressure will increase, but the water sprinkling means 50 will operate and water will be sprinkled on the air-cooled condenser 1, thereby suppressing the increase in the condensing pressure. increases, and the temperature of the controlled object converges well within its control range.

On the other hand, when the temperature to be controlled is within the control range, the water sprinkling control means 63 does not operate and water is not sprayed to the air-cooled condenser 1, so the refrigerating capacity is maintained at the same value. , convergence of the temperature of the controlled object to the target value is maintained well.

(Example) Hereinafter, an example of the present invention will be described based on the drawings from FIG. 2 onwards.

FIG. 2 shows a refrigerant piping system in which the present invention is applied to a separate air-conditioning system equipped with two compressors, where X is an outdoor unit, Y ₁ and Y ₂ are indoor units, and the outdoor unit Inside is 2
The outdoor heat exchanger 1 is equipped with an air-cooled outdoor heat exchanger 1 that is blown by blower fans 1C and 1C of the stand.
The first heat exchanger section 1a and the second heat exchanger section are independent from each other.
The equipment for the first heat exchanger section 1a is located on the left side of the figure inside the outdoor unit X, and the equipment for the second heat exchanger section 1b is located on the right side of the figure. They are arranged together and have the same configuration.

Next, the first and second outdoor heat exchanger sections 1
To explain the equipment for a and 1b, 2,
2' is a compressor, 3, 3' are four-way switching valves, 4, 4' are heating expansion valves, 5, 5' are check valves that bypass the heating expansion valves 4, 4', 6, 6' is a liquid receiver, 7,
7' is an accumulator, and each of the devices 1a to 7'
7, 1b to 7' are connected through refrigerant pipes 8, 8', respectively, so that refrigerant can flow therethrough.

On the other hand, the indoor unit _Y1 has an indoor heat exchanger 10 divided into a first heat exchanger section 10a and a second heat exchanger section 10b, which are independent from each other, like the outdoor heat exchanger 1. The equipment related to the first heat exchanger section 10a is arranged on the left side of the figure, and the second heat exchanger section 10b is arranged on the right side of the figure. 11,1
1' is a cooling expansion valve; 12, 12' is a check valve that bypasses the cooling expansion valve 11, 11';
3' is a refrigerant solenoid valve that opens and closes during cooling and heating operations to allow or block the flow of refrigerant; 1;
4 and 14' are check valves for cooling, and 15 and 15' are check valves for heating, and each of the devices 10a to 15, 10b
15' are connected to each other by refrigerant pipes 16 and 16' so that refrigerant can flow therethrough. In addition, the indoor unit
_Y2 has the same internal configuration as the above indoor unit _Y1 .

Then, the above outdoor unit X and indoor unit
Y ₁ and Y ₂ are connected to each other by refrigerant pipes 17 and 17' so that refrigerant can circulate, forming first and second refrigerant circulation systems 18 and 18', and during cooling operation, four-way By switching the switching valves 2 and 2' as shown by the solid line in the figure and circulating the refrigerant as shown by the solid line arrow in the figure, heat is absorbed from the indoor air in the first and second heat exchanger sections 10a and 10b of the indoor heat exchanger 10. The heat is repeatedly radiated to the outside air by the first and second heat exchanger parts 1a and 1b of the outdoor heat exchanger 1, thereby cooling the room. By switching the refrigerant as shown by the broken line and circulating the refrigerant as shown by the broken line arrow, the exchange of heat is reversed to heat the room.

Around the outdoor heat exchanger 1 which acts as a condenser during the cooling operation, a water spraying means is provided to spray water toward the first and second heat exchanger sections 1a and 1b of the outdoor heat exchanger 1. A water spray nozzle 50 is arranged, and a water supply solenoid valve 20WS that opens and closes the water supply pipe 51 to allow/stop water supply is interposed in the water supply pipe 51 of the water spray nozzle 50, and opens the water supply solenoid valve 20WS. By spraying water from the water spray nozzle 51 to the outdoor heat exchanger 1, the condensing pressure of the outdoor heat exchanger 1 is lowered and the condensing capacity is increased. In addition, in indoor unit Y ₁ , 20
is an indoor ventilation fan.

Next, the above outdoor unit
Figure 3 shows the internal configuration of the operation control circuit A that controls each built-in device of _Y1 . In the figure, 25 is a commercial power source with a power frequency of 60 Hz, MC ₁ is a first compressor motor that drives the first compressor 2 belonging to the first refrigerant circulation system 18, and MC ₂ is a second refrigerant. A second compressor motor that drives the second compressor 2' belonging to the circulation system 18', 26 an inverter that increases or decreases the frequency of the voltage supplied to the first compressor motor MC ₁ , and MF ₀ an outdoor motor. A motor for driving the ventilation fan 1c, MF _A , is a motor for driving the indoor ventilation fan 20. Note that the illustration of the electric circuit on the indoor unit _Y2 side is omitted. Further, 30 is a controller, and the output side of the controller 30 is connected to the first compressor motor MC1 from the inverter 26.
a normally open contact 52 that allows or prevents power supply to the
A first inverter-side electromagnetic switch 52CY1 having _CY1-1 and a normally open contact 52C1 for supplying power from the commercial power supply 25 to the first compressor motor MC1.
- the first commercial power supply side electromagnetic switch 52C with ₁
1, and a second commercial power supply side electromagnetic switch 52C2 having a normally open contact _52C2-1 that similarly supplies power from the commercial power supply 25 to the second compressor motor MC2;
Normally open contact 52CY that allows or prevents power supply from the inverter 26 to the second compressor motor MC2
2-2 second inverter side electromagnetic switch 5 having ₁
2CY2, an outdoor fan relay (having a normally open contact _52F0-1 that controls the outdoor fan drive motor _MF0 ) 52F0, and an indoor fan drive motor MF0)
An indoor ventilation fan relay 52F _A having a normally open contact 52F _A-1 that controls MF _A , and the water supply solenoid valve 2
0WS are connected to the inverter 26, for example, 30, 40, 50 or 60Hz.
Each frequency setting signal is output.

Further, on the input side _of the controller 30, a room temperature sensor T _A consisting of a thermistor or the like that individually detects the indoor temperature as the temperature to be controlled for each of the indoor units Y 1 and Y ₂ (the one shown is for the indoor unit Y ₁
An outside air sensor as an overload detection means that detects overload conditions based on the room temperature signal of
The outside air temperature signals of TH _{and B} are respectively input.
Then, the controller 30 detects the difference between the room temperature signal value of the room temperature sensor TH _A and the set value (room temperature target value), that is, when the air conditioning load reaches 50% of the air conditioning capacity, Electromagnetic switch 52
The normally open contact 52C- ₁ of C2 is controlled to open and close, and the second
While stopping the compressor 2' or controlling the capacity to be fixed by the commercial power supply 25, the normally open contact _52CY1-1 of the first inverter side electromagnetic switch 52CY1 is closed to connect the inverter 26 and the first compressor motor MC1. and outputs a frequency setting signal according to the air conditioning load to the inverter 26 to control the capacity of the first compressor 2 in four stages according to the air conditioning load. , 2' is made variable in eight stages.

Further, the inverter 26 is configured to output an inverter abnormality signal in the event of a failure such as destruction of the built-in power transistor due to overcurrent, and this inverter abnormality signal is input to the controller 30.

Note that the commercial power supply 25 is connected to the input side of the controller 30 as a protection device for the compressors 2 and 2'.
from the first and second compressor motors MC1, MC
Normally closed contacts 51C1 of the first and second overcurrent relays 51C1 and 51C2 that detect overcurrent to 2
_-1 , _51C2-1 and each compressor motor MC1,
Normally closed contacts ( _49C1-1 ), _49C2-1 ) of the compressor protection thermometer that detects the coil temperature of MC2,
High pressure switches 63H1, 63H2) that detect high pressure from each compressor 2, 2' (see Figure 2)
Normally closed contacts _63H1-1 and _63H2-1 are connected respectively, and when the supply current from the commercial power supply 25 to each compressor 2, 2', motor coil temperature or high pressure rises excessively, each compressor Motor MC1,
The MC2 is immediately stopped to prevent damage to the compressors 2 and 2'.

Next, the compressor 2 by the controller 30,
The variable control of the total capacity 2' will be explained based on the flowchart of FIG. 4, taking the case of cooling operation as an example. Start and step S ₁ to set the room temperature sensor
Start measuring the sampling time T (for example, 3 minutes) of the room temperature signal from TH _A from the “0” value, and then step
After waiting for the sampling time T to elapse in step _S2 , the room temperature signal value tn from the room temperature sensor _THA is read in step _S3 .

After that, in step _S4 , the room temperature signal value tn is within a predetermined set temperature range including the set temperature ts (ts−0.5<tn<ts
+0.5), and if NO, which is not within the set temperature range, further proceeds to step _S5 to determine if the room temperature signal value tn is greater than or equal to the upper limit of the set temperature range, tn≧ts+0.5.
If it is greater than the upper limit of YES (tn≧ts+0.5), in step _S6 , the difference between the current and previous room temperature signal values tn−tn− ₁ is determined to determine the state of change in the room temperature.
Calculate the tn of NO for which this temperature difference is less than the “0” value.
If −tn− ₁ <0, it is determined that the temperature is decreasing toward the set temperature ts, and the compressors 2 and ₂ ' are
while keeping the total capacity of tn−tn− ₁
When the temperature rises away from the set temperature ts, which is YES (≧0), the total capacity of the compressors 2 and 2' is first determined in step _S8 in order to increase the air conditioning capacity, and if this is not the maximum, the total capacity is determined in step _S9. compressor 2, 2'
After increasing the total capacity of the compressors by one level, the process returns to step _S1 . On the other hand, if the total capacity of the compressors is YES, which means the total capacity of the compressors is at _its maximum, the outside air sensor is After reading the outside air temperature T signal from TH _B , in step _S11 , the outside air temperature T is compared with the set value _T0 on the high temperature side.
In case of low outside temperature of NO with T<T ₀ , step
In _S16 , the water supply solenoid valve 20WS is closed and the process returns to step _S1 without operating the water spray nozzle 20WS.If T≧ _T0 (YES), the water supply solenoid valve 20WS is opened in step _S12 . , water is sprayed onto the outdoor heat exchanger 1 from the water spray nozzle 20WS, and the process returns to step _S1 .

On the other hand, in step _S5 above, the room temperature signal value tn is tn≦ts
If NO, which is less than the lower limit of the set temperature range of −0.5, the difference tn−tn− ₁ between the current and previous room temperature signal values is calculated in step _S13 , and this temperature difference exceeds the “0” value. If NO, it is determined that the temperature is rising toward the set temperature ts, and the compressor ₂ ,
While maintaining the total capacity of compressor 2' as it is and returning to step _S1 , when the temperature falls away from the YES set temperature ts where tn-tn- ₁ ≦0, the compressor ₂ ,
Lower the total capacity of 2' by one step and return to step _S1 .

On the other hand, in step _S4 above, the room temperature signal value tn is within the room temperature control range, ts - 00.5 < tn < ts + 0.5.
If the control is good (YES), the total capacity of the compressors 2 and 2' is maintained as is in step _S15 , and the process returns to step _S1 .

Therefore, in the operation flow shown _in FIG. 3 above, _the compressors 2 _{, 2} ' are
A capacity control means 60 is configured to control the capacity according to the refrigerating load. Also, step S ₈
In step _S4 , the maximum time detection means 61 detects when the capacity of the compressors 2, 2' is at its maximum, and the within-range detection means 62 detects when the indoor temperature tn of the controlled object is within the room temperature control range. It consists of Furthermore, in step _S12 , the outside air sensor TH _B
And at the maximum time, each detection means 61, 62 within the range
In response to _the output of A water sprinkling control means 63 configured to spray water onto the air-cooled condenser 1 is configured.

Therefore, in the above embodiment, when the outside air temperature T is overloaded and the set value _T0 or higher, the compressors 2,
2' is at its maximum capacity, water nozzle 5
The operation of the water spray nozzle 50 is controlled according to the air conditioning load, and when the room temperature signal value tn is not within the room temperature control range and the load is high, the water spray nozzle 50 is controlled by the water spray control means 63 to prevent water from flowing into the outdoor heat exchanger 1. This reduces the condensing pressure of the outdoor heat exchanger 19 and increases the air conditioning capacity, so that the room temperature signal value tn converges well toward its target value ts.

On the other hand, when the room temperature signal value tn is within the room temperature control range and the load is low, the water sprinkling control means 63 does not operate and the water nozzle 50 does not spray water to the outdoor heat exchanger 1, so that excessive air conditioning does not occur. , room temperature signal value tn
remains within the room temperature control range, and convergence to the room temperature target value ts is maintained well. Therefore, it is possible to increase or decrease the air conditioning capacity appropriately according to the load state of the outdoor heat exchanger 1, thereby improving the convergence of the room temperature to the target value.

In the above embodiment, the temperature to be controlled is room temperature, but in the case of a chiller or the like, the temperature of the water is the temperature to be controlled. Furthermore, it goes without saying that the present invention is not limited to air-conditioning devices, but can also be applied to other refrigeration devices, such as devices exclusively for cooling.

(Effects of the Invention) As explained above, according to the refrigerating capacity control device for a refrigerating machine of the present invention, when the air-cooled condenser is overloaded and a refrigerating capacity higher than the maximum capacity of the compressor is required, at high load, In addition to increasing the refrigeration capacity by spraying water on the air-cooled condenser, we also ensured good convergence of the temperature to be controlled by not spraying water during low loads, increasing control accuracy of the target temperature and improving refrigeration performance. It is possible to improve the

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. Figures 2 to 4 show embodiments of the present invention, Figure 2 is a refrigerant piping system diagram when applied to a separate air conditioning system, Figure 3 is an electric circuit diagram showing an operation control circuit, and Figure 4 FIG. 2 is a flowchart showing operation control of the controller. 1... Outdoor heat exchanger, 2, 2'... Compressor, 26...
Inverter, 30... Controller, 50... Water nozzle, 20WS... Water supply solenoid valve, TH _A ... Room temperature sensor, TH _B ... Outside air sensor, 60... Capacity control means,
61...Maximum time detection means, 62...Inside detection means,
63... Watering control means.

Claims (1)

[Claims] 1 variable capacity compressors 2, 2';
2' according to the refrigerating load, a water spraying means 50 for spraying water on the air-cooled condenser 1, an overload detection means TH _B for detecting an overload, and the compressor 2'. maximum time detection means 61 for detecting the maximum capacity of 2, 2', within-range detection means 62 for detecting when the temperature of the controlled object is within the control range, and each of the detection means TH _B , 61, 62.
In response to the output of Watering control means 63 for operating
A refrigeration capacity control device for a refrigerator, characterized by comprising: