JP6052066B2 - Refrigeration equipment - Google Patents

Description

The present invention relates to a refrigeration apparatus that performs a cooling operation even in winter. When the outside air temperature is low, the compressor fan is started and stopped (ON / OFF) to ensure a compressor compression ratio and stably operate. This is a technology that can reduce the frequency of ON / OFF of the condenser fan.

Refrigeration equipment for low-temperature warehouses, refrigeration equipment for refrigeration / freezing showcases, etc. require cooling operation even in the winter, and this type of conventional refrigeration equipment has a condensation pressure below a predetermined value when the outside air temperature is low A condensing pressure control device is provided to prevent this.
As a condensing pressure control device for a conventional refrigeration system, the condenser includes two divided condensers, a condenser fan that is turned off by a first high-pressure switch for each of the divided condensers, and an inlet of one of the divided condensers. There is known an electromagnetic valve that is provided on the side and is controlled to be opened and closed by a second high-pressure switch, and a condensing pressure adjusting valve that is connected to the outlet side of the condenser (see, for example, Patent Document 1). ).

Further, as a condensing pressure control device for a conventional refrigeration apparatus, the condenser includes a plurality of heat exchangers, a condenser fan disposed corresponding to each of the heat exchangers, and the heat exchangers. It is provided that includes a partition plate that limits the heat exchange area between the outside air from the condenser fan and the heat exchanger, and a control device that controls the rotation speed of the condenser fan ( For example, see Patent Document 2).

Microfilm of Japanese Utility Model No. 60-703 (Japanese Utility Model Application No. 61-116975) JP 2004-245487 A

The conventional technique described in Patent Document 1 divides the condenser into two units, provides two condenser fans, and further provides an electromagnetic valve, a condensation pressure adjusting valve, etc. There was a problem of becoming.
In addition, the conventional technique described in Patent Document 1 enables the condensing capacity to be adjusted according to the degree of the decrease in the outside air temperature, but the condensation pressure is set by setting the first high-pressure switch due to the decrease in the outside air temperature. When the value is lower than the value, the condenser fan is turned off. When the condensation capacity is lowered and the condensation pressure is increased to reach a set value, the condenser fan is turned on.

Therefore, in the conventional technique described in Patent Document 1, when the outside air temperature is lowered to a temperature at which the first high-pressure switch operates, the frequency of the condenser fan is high (ON / OFF), and the fan motor, relay There was a problem that the durability of such devices was inferior.
Moreover, since the conventional technique described in Patent Document 2 includes a condenser as a plurality of heat exchangers, a condenser fan capable of controlling the rotation speed is provided for each, and a partition plate that limits a heat exchange area is provided. Although the decrease in the condensation pressure can be suppressed even when the outside air temperature decreases, there is a problem that the configuration of the refrigeration apparatus becomes complicated.

  The present invention solves the problems in the conventional refrigeration apparatus described in Patent Document 1 and Patent Document 2, and reduces the frequency of ON / OFF of the condenser fan while the structure of the refrigeration apparatus is simple. The purpose is that.

The refrigeration apparatus of the present invention includes a compressor, a condenser, a condenser fan, an expansion valve, and an evaporator. When the condensation pressure falls to a predetermined value on the low side, the condenser fan is stopped and the condensation pressure is reduced. In the refrigeration system that performs the cooling operation in winter by operating the condenser fan when the temperature rises to the high side first predetermined value,
Fan operation time for measuring the fan operation time from when the condensing pressure rises to the high first predetermined value and the condenser fan starts operating until when the condensing pressure falls to the low predetermined value and the condenser fan stops Measuring means;
A first comparison means for comparing the fan operation time measured by the fan operation time measurement means and the first set value with the fan operation time and the reference value;
First predetermined value changing means for changing the high-side first predetermined value to a high-side second predetermined value higher than the high-side first predetermined value when the fan operation time is equal to or less than the first set value by the first comparing means; It is equipped with.

In the refrigeration apparatus of the present invention, when the outside air temperature is lowered and the condenser fan is turned ON / OFF, when the condenser fan operation time is equal to or less than the preset first set value, the condenser fan is operated from the stop. The high-side first predetermined value of the condensing pressure to be switched to the higher-side second predetermined value is changed to a higher high-side second predetermined value. The frequency of starting and stopping can be lowered, and the durability of the device can be improved.

It is a schematic explanatory drawing of the freezing apparatus which concerns on Embodiment 1-4 of this invention. It is explanatory drawing which shows the fluctuation | variation with the time passage of the condensation pressure at the time of ON / OFF of the fan for condensers in the winter of the refrigeration apparatus which concerns on Embodiment 1-4 of this invention. It is a flowchart which shows the change of the setting value of the condensing pressure which turns OFF the condenser fan by the operation time of the condenser fan in the winter of the refrigerating device which concerns on Embodiment 1 of this invention. It is a flowchart which shows the change of the setting value of the condensing pressure which turns OFF a condenser fan by the stop time of the condenser fan in the winter of the refrigerating device which concerns on Embodiment 2 of this invention. It is a flowchart which shows the change of the setting value of the condensation pressure which turns off the condenser fan by the time of 1 cycle of ON / OFF of the condenser fan in the winter of the refrigerating device which concerns on Embodiment 3 of this invention. It is a flowchart which shows the change of the setting value of the condensation pressure which turns OFF the fan for condensers with the external temperature in the winter of the freezing apparatus which concerns on Embodiment 4 of this invention.

Embodiment 1 FIG.
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic explanatory view of a refrigeration apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a refrigeration apparatus that performs a cooling operation even in winter.

The refrigeration apparatus 1 includes a compressor 11 having a constant rotational speed, an oil separator 12, a condenser 2, a liquid receiver 13, an expansion valve 14, an evaporator 15, a suction accumulator 16, and the compressor 11 in this order through a refrigerant pipe 17. Connected to form a refrigerant circulation circuit.
The refrigeration apparatus 1 is a refrigerated showcase provided in a store for cooling food, and the cooling operation is performed even in winter when the outside air temperature is low.

The condenser 2 is an air-cooled type that is cooled by outside air, and includes a condenser fan 3 and a fan motor 31 having a constant rotation speed.
Further, in the first embodiment, the refrigeration apparatus 1 is provided with the condensation temperature sensor 21 in the condenser 2 to detect the condensation temperature (corresponding to the condensation pressure) and turn the fan motor 31 on / off via the control device 4. Like to do.

In FIG. 1, reference numeral 18a denotes a high / low pressure switch for detecting high and low pressures to stop the refrigeration apparatus 1 at abnormally high pressure or abnormally low pressure, and 18b denotes suction of the lubricating oil separated by the oil separator 12 into the compressor 11. An oil return pipe returning to the side, 18c and 18d are operation valves, 18e is a strainer, and 18f is a check valve.
Next, a description will be given of fluctuations of the condensing pressure and the evaporating pressure with the passage of time when the condenser fan is turned ON / OFF when the outdoor temperature in winter shown in FIG. 2 is constant.

In FIG. 2, a curve L1 indicated by an upper thin line and a curve L3 indicated by a lower thin line are controlled so as to turn on the condenser fan 3 that has been turned off due to the condensation pressure rising to the high first predetermined value P1. The fluctuations in the condensation pressure and evaporation pressure are shown.
Further, the curve L2 indicated by the upper bold line and the curve L4 indicated by the lower bold line are used when the condenser fan 3 that has been turned off by increasing the condensation pressure to the high-side second predetermined value P2 is controlled to be turned on. The fluctuations in the condensation pressure and the evaporation pressure are shown.

In the case of the curve L1 in which the condensation pressure rises to the high-side first predetermined value P1 and the condenser fan 3 is turned ON, the condenser fan 3 is turned OFF by decreasing the condensation pressure to the low-side predetermined value P0 at time Ts. At time LTa, the condensation pressure rises to the high-side first predetermined value P1 and is turned on. At time LTb, the condensation pressure falls to the low-side predetermined value P0 and turns off, and this cycle is repeated.
Further, in the case of the curve L2 in which the condenser fan 3 is turned ON when the condensation pressure is the high-side second predetermined value P2, the condenser fan 3 is turned OFF when the condensation pressure drops to the low-side predetermined value P0 at time Ts. At HTa, the condensation pressure rises to the high-side second predetermined value P2 and is turned on. At time HTb, the condensation pressure falls to the low-side predetermined value P0 and turns off, and this cycle is repeated.

As apparent from the above description of FIG. 2, the condenser fan 3 has a constant rotation speed, and therefore, when the outside air temperature decreases in winter, the condensation capacity for cooling the condenser 2 increases, resulting in excessive cooling and the condensation pressure. As a result, the required high / low pressure difference of the compressor 11 cannot be obtained.
Therefore, in the first embodiment, the refrigeration apparatus 1 is provided with a condensing temperature sensor 21 in the condenser 2 to detect the condensing temperature (corresponding to the condensing pressure) and the condensing pressure becomes a predetermined lower limit. The condenser fan 3 is turned off at the value P0.

When the cooling operation is continued with the condenser fan 3 turned off, the condensation pressure increases, and the condenser fan 3 is turned on when the condensation pressure detected by the condensation temperature sensor 21 reaches a predetermined value. .
Here, the condensation pressure at which the condenser fan 3 is turned on is set to be low within a range in which the ON / OFF frequency is allowed before and after the winter season of late autumn or early spring, and the condensation pressure is low. It is designed to be energy-saving cooling operation.

However, when the outside air temperature in winter is low, the frequency of ON / OFF of the condenser fan 3 is increased, and the contact point of the relay that turns the fan motor 31 ON / OFF and the durability of the fan motor 31 itself are deteriorated. Thus, the ON / OFF frequency was lowered.
Hereinafter, the flow chart showing the change of the set value of the condensation pressure for turning off the condenser fan 3 according to Embodiment 1 shown in FIG. 3 will be described.

The control in the flow chart of FIG. 3 is performed by the condenser temperature sensor 21 and the control device 4 shown in FIG. 1 so that the outside air temperature level can be determined without using the outside air temperature sensor, and the condenser fan 3 is turned off. The set value of pressure is changed.
Although not shown, the control device 4 incorporates a microcomputer, a storage device, input means, output means, software, etc., so that each time measurement means, each comparison means, and each predetermined value change means can be controlled. It is composed.

In FIG. 3, in step S <b> 1, it is determined whether the operation time of the refrigeration apparatus 1 has passed a set time (for example, 60 minutes).
In step S2, it is determined whether the time from ON to OFF of the condenser fan 3 (for example, time LTb-time LTa in FIG. 2) is equal to or less than a first set value (for example, 5 minutes).

In step S2, a determination is made by the fan operating time measuring means and the first comparing means of the control device 4. If the time is equal to or less than the first set value (Y), the process proceeds to step S3.
In step S3, the condensing pressure at which the condensing fan 3 is turned ON is set to a high-side second predetermined value P2 (for example, 1.7 MPaG) higher than the high-side first predetermined value P1 (for example, 1.5 MPaG).

In step S3, the first predetermined value changing means of the control device 4 changes the condensing pressure at which the condensing fan 3 is turned on from the high side first predetermined value P1 to the high side second predetermined value P1 higher than the high side first predetermined value P1. The predetermined value P2 is set.
Proceeding from step S3 to step 4, the operation time measuring means of the control device 4 determines whether or not the operation time of the refrigeration apparatus 1 has passed a set time (for example, 60 minutes), and when the set time has passed (Y) Proceed to step S5.

In step S5, it is determined whether the time from ON to OFF of the condenser fan 3 (for example, time HTb-time HTa in FIG. 2) is equal to or greater than a second set value (for example, 30 minutes).

In step S5, determination is made by the fan operating time measuring means and the first comparing means of the control device 4. If the time is equal to or greater than the second set value (Y), the process proceeds to step S6.
In step S6, the condensing pressure at which the condensing fan 3 is turned on by the first predetermined value changing means of the control device 4 is set from the high-side second predetermined value P2 to the high-side first predetermined value P1 (for example, 1.5 MPaG). It is.

Then, the process returns from step S6 to step S1.
In step S5, if the time from ON to OFF of the condenser fan 3 (eg, time LTb-time LTa in FIG. 2) is less than the second set value (eg, 30 minutes) (N), the process returns to step S4. The determination in step S5 is repeated.

Next, in step S2, if the time from ON to OFF of the condenser fan 3 (for example, time LTb-time LTa in FIG. 2) exceeds the first set value (for example, 5 minutes) (N), The process returns to S1.

As described above, in step S2, when the time from ON to OFF of the condenser fan 3 is equal to or less than the first set value (Y), the frequency of ON / OFF of the condenser fan 3 is high. Thus, the setting is changed from the high-side first predetermined value to the high-side second predetermined value.
In step 2, if the time from ON to OFF of the condenser fan 3 exceeds the first set value (N), the process returns to step S1 and the state is maintained to save energy. Will continue.

In step S5, if the time from ON to OFF of the condenser fan 3 is equal to or longer than the second set value (Y), which is longer than the first set value, the frequency of ON / OFF of the condenser fan 3 is low. In step S6, the setting is changed from the high-side second predetermined value to the high-side first predetermined value.
By this step S6, the refrigeration apparatus 1 can be switched to the energy saving operation.

Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to FIG.
In the first embodiment, the condensation pressure at which the condenser fan 3 is turned on is set by the length of the operation time of the condenser fan 3, but in the second embodiment, the stop time of the condenser fan 3 is changed instead. The difference is that it is done in short and long.

That is, in the first embodiment, the operation time from ON to OFF of the condenser fan 3 is compared with the first set value (step S2) or the second set value (step S5) in step S2 and step S5 in FIG. Was.
In contrast, in the second embodiment, the stop time (LTa-TS in FIG. 2) from OFF to ON of the condenser fan 3 is compared with the third set value in step S21 of FIG. 4, and the condensation is performed in step S51. The difference is that the stop time (HTa-TS in FIG. 2) from OFF to ON of the device fan 3 is compared with the fourth set value.

The second embodiment uses the fan stop time measuring means, the second comparison means for comparing the fan stop time with the reference value, and the second predetermined value changing means of the control device 4.
The other configuration of the second embodiment is the same as that of the first embodiment, and the operation thereof is also the same as that of the first embodiment, so that the description thereof is omitted.

Embodiment 3 FIG.
A third embodiment of the present invention will be described with reference to FIG.
In the first embodiment, the condensation pressure at which the condenser fan 3 is turned on is set by the length of the operation time of the condenser fan 3, but in the third embodiment, the condenser fan 3 is switched from ON to OFF instead. This is different in that it is performed in the length of one cycle time until the next ON via the.

That is, in the first embodiment, the operation time from ON to OFF of the condenser fan 3 is compared with the first set value (step S2) or the second set value (step S5) in step S2 and step S5 in FIG. Was.
On the other hand, in the third embodiment, a fifth time is set for one cycle time (LTb-TS in FIG. 2) from ON to OFF of the condenser fan 3 to the next ON in step S22 of FIG. Compared with the value, in step S52, the time of one cycle from ON to OFF of the condenser fan 3 until the next ON (HTb-TS in FIG. 2) is compared with the sixth set value. Is different.

The third embodiment uses the one cycle time measuring means of the control device 4, the third comparing means for the time of one cycle and the reference value, and the third predetermined value changing means.
The other configuration of the third embodiment is the same as that of the first embodiment, and the operation thereof is also the same as that of the first embodiment, so that the description thereof is omitted.

Embodiment 4 FIG.
Next, description will be made with reference to the flowchart of FIG. 6 showing a change in the set value of the condensation pressure for turning off the condenser fan 3 according to the fourth embodiment.

The control in the flowchart of FIG. 6 is performed by changing the setting value of the condensation pressure for turning off the condenser fan 3 so that the outside air temperature sensor 5 and the control device 4 shown in FIG. I try to do it.
Although not shown, the control device 4 includes a microcomputer, a storage device, input means, output means, software, etc., and these constitute time measurement means, temperature comparison means, and temperature change maintenance means. ing.

In FIG. 6, it is determined in step S11 whether the operation time of the refrigeration apparatus 1 has passed a set time (for example, 60 minutes), and the process proceeds to step S12 when the set time has passed (Y).
In step S12, it is determined whether or not the outside air detected by the outside air temperature sensor 5 is equal to or lower than a set temperature (for example, 5 ° C.).

In step S12, determination is made by the outside air temperature sensor 5 and the temperature comparison means of the control device 4. If the outside air is equal to or lower than the set temperature (Y), the process proceeds to step S13.
In step S13, the condensing pressure at which the condensing fan 3 is turned on is set to a high-side second predetermined value P2 (for example, 1.7 MPaG) higher than the high-side first predetermined value P1 (for example, 1.5 MPaG).

In step S13, the condensing pressure at which the condensing fan 3 is turned ON by the temperature change maintaining means of the control device 4 is increased from the high-side first predetermined value P1 to the high-side second predetermined value higher than the high-side first predetermined value P1. It is set to P2.
Then, the process returns from step S13 to step S11.

In step S12, if the outside air exceeds the set temperature (N), the process proceeds to step S14.
In step S14, the condensing pressure for turning on the condensing fan 3 is set to the high-side first predetermined value P1, and the condensing pressure for turning on the condensing fan 3 in step S12 is the high-side first predetermined value P1. If there is, the predetermined value P1 is maintained.

If the condensing pressure at which the condensing fan 3 is turned on in step S12 is the high-side second predetermined value P2, the predetermined value P2 is changed to the high-side first predetermined value P1 in step S14.
In the fourth embodiment, as described above, if the outside air temperature is directly detected by the outside air temperature sensor 5 and the outside air temperature is within the allowable range of the ON / OFF frequency of the condenser fan 3, the high side first predetermined The value P1 is set to save energy.

If the outside air temperature is too high, the condenser fan 3 is set to the high second predetermined value P2 to reduce the ON / OFF frequency.

In the first to fourth embodiments described above, the condensation temperature sensor 21 is provided to detect the condensation pressure, but the pressure on the inlet side of the condenser 2 is directly detected by the pressure sensor. May be.
In the above first to third embodiments, the fan operation time of the first embodiment, the fan stop time of the second embodiment, and the time from the fan ON to the next fan ON of the third embodiment are all once or Although the time of one cycle is measured, the time of a plurality of times or a plurality of cycles may be measured and averaged.

In the first to third embodiments described above, when the condensation pressure at which the condenser fan 3 is turned on is the second predetermined value, the respective times are set as the second set value in the first embodiment and the second in the second embodiment. Compared with the four setting values and the sixth setting value in the third embodiment, it was determined whether to set the first predetermined value or to keep the second predetermined value, but this determination is omitted. Alternatively, the first set value may be intermittently compared with the first set value in the first embodiment, the third set value in the second embodiment, and the fifth set value in the third embodiment after a certain period of time.
In the fourth embodiment described above, the comparison between the outside air temperature detected by the outside air temperature thermistor 5 and the set temperature is intermittently performed every set time, but instead, the set temperature is differentially set. May be provided to return to the second predetermined value below the first set temperature, and return to the first predetermined value above the second set temperature that is higher than the first set temperature (for example, 1 ° C.).

DESCRIPTION OF SYMBOLS 1 Refrigeration apparatus 11 Compressor 14 Expansion valve 15 Evaporator 2 Condenser 21 Condensing temperature sensor 3 Condenser fan 4 Controller 5 Outside temperature sensor P0 Low side predetermined value P1 High side first predetermined value P2 High side second predetermined value

Claims (8)

A compressor, a condenser, a condenser fan, an expansion valve, and an evaporator are provided, and when the condensation pressure falls to a predetermined value on the low side, the condenser fan is stopped and the condensation pressure is increased to a first predetermined value on the high side. In a refrigeration apparatus that performs cooling operation in winter by operating the condenser fan when the value rises,
The fan operating time from when the condensing pressure rises to the first predetermined value on the high side and the condenser fan starts operating until the condensing pressure falls to the predetermined value on the low side and the condenser fan stops Fan operating time measuring means for measuring,
A first comparison means for comparing the fan operation time measured by the fan operation time measurement means and a first set value with the fan operation time and a reference value;
When the fan operation time is less than or equal to the first set value by the first comparing means, the first high side predetermined value is changed to a high side second predetermined value higher than the high side first predetermined value. A refrigeration apparatus comprising a predetermined value changing means. A fan that measures the fan operation time from when the condensing pressure rises to the second predetermined value on the high side and the condenser fan starts operation until when the condensing pressure falls to the predetermined value on the low side and the condenser fan stops Operating time measuring means;
A first comparison means for comparing the fan operation time measured with the fan operation time measurement means and a second set value longer than the first set value with a fan operation time and a reference value;
And a first predetermined value changing means for changing the high-side second predetermined value to the high-side first predetermined value when the fan operation time is equal to or longer than the second set value by the first comparing means. The refrigeration apparatus according to claim 1. A compressor, a condenser, a condenser fan, an expansion valve, and an evaporator are provided, and when the condensation pressure falls to a predetermined value on the low side, the condenser fan is stopped and the condensation pressure is increased to a first predetermined value on the high side. In a refrigeration apparatus that performs cooling operation in winter by operating the condenser fan when the value rises,
A fan stop time from when the condensing pressure is lowered to the predetermined value on the low side and the condenser fan is stopped until when the condensing pressure is increased to the first predetermined value on the high side and the condenser fan is started. Fan stop time measuring means for measuring,
A second comparison means for comparing the fan stop time and the reference value with the fan stop time measured by the fan stop time measurement means;
A second side for changing the high-side first predetermined value to a high-side second predetermined value higher than the high-side first predetermined value when the fan stop time is equal to or shorter than the third set value by the second comparing means; A refrigeration apparatus comprising a predetermined value changing means. A fan that measures the fan stop time from when the condensing pressure is lowered to a predetermined value on the low side and the condenser fan is stopped until when the condensing pressure is increased to the second predetermined value on the high side and the condenser fan is started. Stop time measuring means,
A second comparison means for comparing the fan stop time measured with the fan stop time measurement means with a fourth set value that is longer than a third set value, and a fan stop time and a reference value;
And second predetermined value changing means for changing the high-side second predetermined value to the high-side first predetermined value when the fan stop time is equal to or greater than the fourth set value by the second comparing means. The refrigeration apparatus according to claim 3. A compressor, a condenser, a condenser fan, an expansion valve, and an evaporator are provided, and when the condensation pressure falls to a predetermined value on the low side, the condenser fan is stopped and the condensation pressure is increased to a first predetermined value on the high side. In a refrigeration apparatus that performs cooling operation in winter by operating the condenser fan when the value rises,
After the condensing pressure rises to the high-side first predetermined value and the condenser fan starts operation, the condensing pressure falls to the low-side predetermined value, the condenser fan stops, and the condensing pressure is 1 cycle time measuring means for measuring the time of 1 cycle until the condenser fan starts operation after rising to the first high side predetermined value;
A third comparing means for comparing the time of one cycle measured by the one cycle time measuring means and the fifth set value with the time of one cycle and a reference value;
When the time of the one cycle is equal to or less than the fifth set value by the third comparing means, the high side first predetermined value is changed to a high side second predetermined value higher than the high side first predetermined value. (3) A refrigeration apparatus comprising a predetermined value changing means. After the condensing pressure rises to the second high predetermined value and the condenser fan starts operation, the condensing pressure falls to the low predetermined value and the condenser fan stops, and the condensing pressure is further increased to the high side second predetermined value. 1 cycle time measuring means for measuring the time of 1 cycle until rising to a predetermined value;
A third comparing means for comparing the time of one cycle measured by the one cycle time measuring means with a sixth set value longer than the fifth set value and a reference value;
And third predetermined value changing means for changing the high-side second predetermined value to the high-side first predetermined value when the time of the one cycle is equal to or longer than the sixth set value by the third comparing means. The refrigeration apparatus according to claim 5. A compressor, a condenser, a condenser fan, an expansion valve, and an evaporator are provided, and when the condensation pressure falls to a predetermined value on the low side, the condenser fan is stopped and the condensation pressure is increased to a first predetermined value on the high side. In a refrigeration apparatus that performs cooling operation in winter by operating the condenser fan when the value rises,
An outside temperature thermistor for detecting the outside temperature;
Temperature comparison means for comparing the outside temperature detected by the outside temperature thermistor with a set temperature;
When the outside air temperature is equal to or lower than the set temperature by the temperature comparison unit, the high side first predetermined value is changed to a high side second predetermined value higher than the high side first predetermined value, and the temperature comparison unit A refrigeration apparatus comprising temperature change maintaining means for maintaining the first predetermined value on the high side when the outside air temperature exceeds the set temperature.   8. The refrigeration apparatus according to claim 7, wherein the comparison between the outside air temperature detected by the outside air temperature thermistor and the set temperature by the temperature comparing means is intermittently performed every set time.

Images