JP2022126605A - Warehouse type refrigerator freezer - Google Patents

Abstract

To achieve suppression against abrupt change in in-storage pressure and energy saving in a warehouse type refrigerator freezer that has a freezing cycle for circulating a refrigerant built in with an out-storage freezer unit including an inverter compressor, and an in-storage cooling unit including a cooling fan driven by a variable speed motor installed in the storage, a cooler, and a temperature expansion valve or electronic expansion valve, coupled through a refrigerant duct, and also comprises a control part performing drive control over the freezing cycle including stop/rotating speed control over the inverter compressor and cooling fan based upon various data from sensors installed outside the storage and at proper points of the freezing cycle.SOLUTION: A refrigerator freezer comprises control means which performs normal operation control in which a freezing cycle operates when an in-storage temperature exceeds a set upper-limit temperature and an inverter compressor is stopped from operating when the in-storage temperature exceeds a lower-limit temperature to place a cooling fan in low air-capacity operation, and controls rotational driving of the cooling fan not in a temperature range of the normal operation into lower-speed operation as the cooling load on the cooler is larger.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a warehouse-type freezer-refrigerator constructed by assembling heat-insulating panels for mainly storing articles under refrigeration/freezing conditions, and particularly relates to drive control of a cooling fan.

As is well known, a refrigerator/freezer circulates refrigerant by connecting an external unit consisting of a compressor, a condenser, and a fan, and an internal unit consisting of an expansion valve, a cooler (evaporator), and a cooling fan. It has a so-called refrigerating cycle. As basic operation control, based on the internal temperature detected by the internal temperature sensor, cooling operation and cooling stop are repeated to keep the internal temperature within a certain range.

In particular, in the refrigeration cycle of a warehouse-type freezer-refrigerator with a variable-speed cooling fan, as an operation control of the cooling fan when the cooling operation is stopped (when the compressor is stopped), for example, Patent Document 1 discloses means for detecting refrigerant temperature and pressure. is provided, and a control means is disclosed that lowers the operation rate of the internal fan as the refrigerant temperature decreases. means for switching) are disclosed.

Further, in Patent Document 2, when the internal temperature exceeds the reference temperature by a predetermined value without intermittently operating the cooling fan while the cooling device operation is stopped, as disclosed in the above Patent Document, the internal fan is operated at a low speed. A control means is disclosed for causing the operation to occur for a predetermined period of time.

In addition, since the cooling efficiency decreases when frost adheres to the internal unit, a defrosting operation is performed by a defrosting heater provided in the internal unit (cooling unit) at regular intervals (Patent Document 2). In particular, in a warehouse-type freezer-refrigerator, in the defrosting process (defrosting operation by a defrosting heater), the operation of the refrigerating cycle is stopped at regular intervals, and the heater circuit is energized to heat the cooler to defrost. After defrosting, the refrigerating cycle is operated. Particularly, the defrosting is performed efficiently in a short time, so the cooler is heated to a high temperature, so after the heating is completed, the air around the cooler becomes a warm air mass. Therefore, if the cooling fan is driven immediately after defrosting and heating, the warm air diffuses into the freezer and raises the temperature inside the freezer as a whole, resulting in a rapid rise in the inside air pressure. In order to cope with this, the start of driving of the cooling fan is slightly delayed.

For example, in home refrigerators, not warehouse refrigerators, if the warm air around the cooler is sent into the freezer compartment after defrosting, the temperature of the food in the freezer compartment will rise. Patent document 3 discloses a control for returning to the rated rotation speed after that.

Japanese Patent Application Laid-Open No. 9-16637. Japanese Patent Application Laid-Open No. 2012-20263. JP-A-61-3972.

The operation control of the refrigeration cycle is based on each signal from the timer and the sensor that detects the temperature state in the refrigerator freezer and the temperature and pressure state of the refrigerant, the rotation speed control (including stop) of the compressor, refrigerant pipe line , the cooling fan is driven/stopped, and the defrosting heater is energized/shut off. The control method of increasing the cooling fan operating rate (rotational speed) and lowering the cooling fan operating rate (rotational speed) is because the capillary tube is used as a means of throttling the refrigerant, which reduces the refrigerant temperature. As a means for increasing the amount of air passing through the cooler. On the other hand, if a thermal expansion valve or an electronic expansion valve is employed as the throttling means, the flow rate of the refrigerant that increases the refrigerant temperature is increased, and the cooling fan is normally operated (constant speed operation). However, it cannot be said that it is necessarily effective for energy conservation.

In addition, in the case of warehouse-type refrigerator-freezers, sudden fluctuations in the internal environment due to factors such as the flow of cold air due to the different shape and volume of the warehouse, the arrangement of stored items in the refrigerator-freezer, and the influence of the outside air temperature, etc. , a situation occurs that cannot be dealt with by normal operation control means.

In particular, the temperature inside the warehouse rises due to the inflow of outside air when cargo is carried in and out of the warehouse-type freezer-refrigerator. The refrigerating cycle is operated at full capacity to quickly lower the temperature inside the refrigerator, but a sudden drop in the temperature inside the refrigerator will cause the air pressure inside the refrigerator to drop sharply, and the ceiling and wall panels will be damaged due to the strong differential pressure. There is a risk that it will be lost. The same applies to the pull-down operation of a refrigerator/freezer in summer (cooling operation for cooling the temperature inside the refrigerator from the outside temperature to the set temperature inside the refrigerator).

In addition, in the control setting for delaying the start time of the cooling fan after the end of defrosting and the low speed rotation control for a certain period of time, the time is set in advance so that the cooling tube is not cooled too much. In a refrigerator/refrigerator, depending on the conditions inside (amount of stored items, layout, set temperature, etc.), when the cooling fan starts to operate or the rated rotation is switched, the warm air mass around the cooler spreads into the freezer. The sudden rise in air pressure throughout the interior can damage the joints of the ceiling and wall panels forming a freezer made of metal sandwich panels or the like, or cause the door to suddenly open. Of course, a refrigerator/freezer is provided with a bi-directional pressure control valve (air intake/exhaust valve) for equalizing the pressure inside and outside the refrigerator, but a sudden pressure rise which cannot be absorbed by the pressure control valve occurs.

Therefore, the present invention provides a warehouse-type freezer-refrigerator that employs a variable speed cooling fan. In addition, by controlling the rotation of the cooling fan, the energy efficiency of the entire freezing and refrigerating operation is improved to save energy. .

The warehouse-type refrigerator/refrigerator according to claim 1 of the present invention comprises a warehouse-shaped storage body constructed with heat-insulating panels, an external refrigerator unit including an inverter compressor, and a variable-speed motor installed inside the warehouse. A cooling fan to be driven, a cooler, and an internal cooling unit including a temperature expansion valve or an electronic expansion valve are connected by refrigerant pipes, and a refrigerating cycle that circulates the refrigerant is built in, and the inside and outside of the refrigerating cycle and appropriate points in the refrigerating cycle Based on various data from the sensor installed in the warehouse-type refrigerator-freezer equipped with a control unit that controls the drive of the refrigeration cycle including the stop and rotation speed control of the inverter compressor and cooling fan, When the set upper limit temperature is exceeded, the refrigeration cycle is activated, and when the lower limit temperature is exceeded, the operation of the inverter compressor is stopped, and normal operation control is performed to operate the cooling fan at a low air volume, and the temperature range is outside the normal operation range. The cooling fan is provided with control means for rotating the cooling fan at a lower speed as the cooling load of the cooler increases.

The refrigerating cycle of the freezer/refrigerator is normally operated by driving the compressor and the condenser fan of the outside refrigerator unit and the cooling fan of the inside cooling unit, and cooling the storage main body by cold air passing through the cooler. By maintaining the interior at a predetermined low temperature, the articles in the storage body are cooled and stored frozen.

The low temperature maintenance (normal operation) of the main body of the storage room uses a variable speed motor for the cooling fan and performs normal cooling operation within the set upper and lower temperature limits. When the temperature exceeds the temperature, the refrigeration cycle operation is stopped. Especially when the refrigeration cycle is stopped, the cooling fan rotates at a low speed (about 5 to 7% of the rated rotation speed) and cools with the minimum air flow so as not to cause temperature unevenness inside the refrigerator. Energy-saving operation that suppresses the temperature rise in the main body of the storage by operating.

Also, for example, when the temperature inside the refrigerator rises due to outside air (warm air) entering the refrigerator when carrying in and out of stored items during normal operation, or when the temperature inside the refrigerator is higher than during normal operation, such as when pull-down operation starts. , the refrigerant evaporation temperature of the cooler increases and the cooling load of the cooler increases. Specifically, the TD temperature (the difference between the temperature of the air sucked into the cooler and the evaporation temperature), the difference between the inside temperature and the evaporation temperature of the refrigerant, the degree of superheat (the temperature of the inlet pipe of the cooler and the temperature of the outlet pipe), and the MOP of the electronic expansion valve When an increase in the cooling load is detected based on data signals such as the (maximum pressure) signal and the operation switching signal from the refrigerator (compressor), the rotation of the cooling fan is reduced as the cooling load increases. be.

That is, using the internal temperature as a reference, the cooling load of the cooler is determined by dividing into a high temperature range, a medium temperature range, and a low temperature range, and the rotation (air volume) of the cooling fan is increased sequentially according to the above criteria. By doing so, it is possible to prevent uneven frost formation that occurs when the cooling fan is operated at high speed (overload operation) or rated operation (100% drive) in the high or medium temperature range. Become. Furthermore, it is possible to prevent damage to the heat-insulating panels constituting the main body of the storage without causing sudden fluctuations in the internal pressure of the storage, and to reduce the number of pressure regulating valves.

Further, in the warehouse-type freezer-refrigerator according to claim 2 of the present invention, in particular, when the rotation drive control of the cooling fan is set to the average temperature in the refrigerator with respect to the design evaporation temperature of the refrigerant as the criterion for determining the cooling load of the cooler, the cooler In the high temperature range where the average internal temperature is 30°C or higher, it operates within a range of 10 to 20% or less against the design evaporation temperature of the refrigerant, drives at 50% or less at 10°C or higher, and operates at 100% at less than 10°C. is based on Warehouse-type freezer-refrigerators are individually different in volume and shape, and the specifications of the coolers are also different.

Further, the warehouse-type freezer-refrigerator according to claim 3 of the present invention is particularly provided with a plurality of internal temperature sensors installed at appropriate locations, an open/close sensor installed at the open/close door provided in the storage, and a cooling fan after the door opening/closing operation. The operating reference temperature of is used as the detection data of the temperature sensor installed in the space near the opening and closing door, and suppresses the pressure fluctuation due to the rapid cooling of the locally generated warm air mass.

Further, in the warehouse-type freezer-refrigerator according to claim 4 of the present invention, a defrost heater is particularly provided in the cooler, and after defrosting is performed at predetermined time intervals and based on refrigerant temperature and pressure detection, the temperature of the cooler After the cooling fan starts to operate at a low speed after the pressure drops, it is controlled to operate at a predetermined speed after the internal pressure stabilizes. Prevent sudden fluctuations in pressure.

As described above, when controlling the cooling operation of the refrigerator, the present invention controls the normal operation of the refrigerator and also controls the rotation speed of the cooling fan to reduce sudden pressure fluctuations and reduce the overall consumption. This enables control to reduce power consumption.

FIG. 2 is an explanatory diagram of the arrangement of cooling cycle constituent members and various sensors according to the embodiment of the present invention. Block explanatory drawing of the same control part.

Next, embodiments of the present invention will be described. The freezer-refrigerator shown in the embodiment includes a warehouse-type storage body 1 combined with heat-insulating panels, an outside refrigerator unit 2 that constitutes a well-known refrigeration cycle, an inside cooling unit 3 installed inside the refrigerator, and a refrigerator. It is composed of a refrigerant pipe line 4 that connects the outside refrigerator unit 2 and the inside cooling unit 3 and circulates the refrigerant.

The storage body 1 includes an opening/closing door 11 with an opening/closing sensor, a pressure control valve 12 for adjusting the pressure inside and outside the storage, a plurality of temperature sensors 13a, 13b, 13c, and 13d disposed at appropriate locations inside the storage, and an outside temperature sensor. A sensor 14 is provided.

The outside refrigerator unit 2 includes a compressor (an inverter compressor whose rotation speed can be changed by changing the frequency), a condenser, and a condenser fan for cooling the condenser. , an outlet liquid tube pressure gauge 21 and an inlet liquid tube pressure gauge 22 are provided. Note that the pressure gauge may be incorporated in advance.

The internal cooling unit 3 is an electronic expansion valve interposed in the refrigerant pipe 4 (especially in the case of a freezer/refrigerator that does not require high-precision operation and has few large fluctuations, a temperature-type outer equalization expansion valve may be adopted). 31, cooler (evaporator) 32, cooling fan 33, fan drive motor (motor with inverter control or variable DC motor) 34 for driving cooling fan 33, defrost heater 35 for defrosting cooler 32, further cooler 32 Inlet tube pressure/temperature gauges 36a, 37a and outlet tube pressure/thermometers 36b, 37b are provided in the inlet and outlet pipelines. However, the pressure gauge may be removed after installation adjustment.

In addition, it is provided with a control unit (arithmetic processing unit) that receives signals from the sensors and controls the operation of each unit. A memory unit that receives signals from the sensors and stores pre-programmed operation control of each driving device based on a timer, an operation signal output means that outputs a predetermined operation signal, and temperature setting, etc., are set from the outside. It is provided with setting input means and the like, and is installed at an appropriate location outside the refrigerator.

The refrigerating cycle of the freezer-refrigerator is operated as usual by driving the compressor and condenser fan of the outside refrigerator unit 2 and the cooling fan 33 of the inside cooling unit 3, and cooling air passing through the cooler 32. maintains the inside of the storage body 1 at a predetermined low temperature to realize cooling and frozen storage of the articles in the storage body 1. It uses a motor.

In a normal cooling operation, the refrigerating cycle is activated when the upper temperature limit preset by the internal temperature sensor 13 is exceeded, and the operation of the refrigerating cycle is stopped when the lower limit temperature is exceeded. When it senses that the cooling set temperature has been reached, the compressor is stopped, but the cooling fan 33 is not stopped immediately, but the fan drive motor 34 of the cooling fan 33 is rotated at a low speed (5 to 7% rotation), and the refrigerator is closed. An energy-saving operation for suppressing temperature rise in the storage body 1 is performed by performing a cooling operation with a minimum air volume so as not to cause temperature unevenness inside.

In particular, the present invention controls the rotation speed of the cooling fan in response to the inside temperature (average value of a plurality of temperature sensors 13a, 13b, 13c, 13d) in the inside cooling operation before reaching the normal cooling operation. Basically, it is driven at 20% or less in the high temperature range (e.g. +30°C or higher than the design evaporation temperature of the refrigerant), 50% or less in the medium temperature range (+10°C or higher), and in the low temperature range. (less than +10° C.) is set to 100%, and if the inside temperature does not reach the expected inside temperature, the rotation speed of the cooling fan 33 is controlled until the normal cooling operation. Of course, the setting of the rotation speed of the cooling fan is a standard, and fine adjustments are made during a test run at the time of installation. Instead of the above-mentioned average internal temperature value, the cooler load is determined based on the TD temperature (difference between cooler intake air temperature and evaporation temperature) and degree of superheat (cooler inlet pipe temperature and outlet pipe temperature). You can

When the internal temperature is higher than the expected internal temperature, if the cooling fan 33 is operated at full capacity to lower the internal temperature quickly, the degree of superheating of the refrigerant increases, forcing the compressor to operate under an overload condition. In addition, even if the rotation speed of the cooling fan 33 is lowered, the heat exchange area of the cooler 32 including the defrost interval for uneven frost formation can be effectively used. As a result, the warm air inside the refrigerator is cooled efficiently, and considering the energy efficiency of cooling inside the refrigerator, the low-speed rotation is superior.

For example, when the stored items are carried into and out of the storage main body 1, the temperature inside the storage chamber rises. move to As a result, sudden fluctuations in the internal pressure due to rapid cooling of the warm air inside the container can be suppressed, and damage to the heat insulating panel of the main body 1 of the container can be prevented.

In particular, when the opening/closing sensor senses the opening/closing of the opening/closing door 11, the internal temperature, which is the control reference for controlling the operation of the cooling fan 33, is used as the temperature detected by the temperature sensors 13a and 13b located near the opening/closing door 11. When adopted, it is possible to suppress rapid pressure changes due to rapid cooling of the warm air in the space near the opening/closing door.

Similarly, during pull-down (operating conditions where the inside temperature is equivalent to the outside temperature to the specified inside temperature), the number of revolutions of the cooling fan 33 is controlled according to the inside temperature. The rotation speed is gradually increased to the low temperature range to prevent continuous overload operation of the compressor and the fan drive motor 34, and the air volume of the cooling fan 33 is reduced to reduce the cold air in the refrigerator. Reduces pressure fluctuations such as sudden pressure drop in the chamber due to the occurrence of flocculation.

In particular, during pull-down operation at high temperatures, the MOP function of the expansion valve and the suction pressure control valve are activated, but due to the decrease in refrigerant pressure in the cooler, the degree of superheat becomes 30°C or more, and the cooling coil frosts. high-speed operation (high-speed cooling) does not necessarily shorten the pull-down time (time until normal operation). By adopting the present invention, an extreme rise in the degree of superheat can be suppressed, frost adheres to the cooler 32 evenly, the energy required for defrosting can be reduced, and as a result the pull-down time can be shortened.

By appropriately controlling the low-speed operation of the cooling fan 33 in this way, a sudden change in the positive pressure and negative pressure in the storage body 1 can be reduced, the door will not be opened due to the positive pressure at night, and the pressure regulating valve It is possible to reduce the number of intake and exhaust valves 12 installed, which helps reduce the cost of equipment, and the part that cannot be covered by the refrigerant control of the electronic expansion valve (or the temperature expansion valve) can be handled by the air volume control of the cooling fan. It is a well-balanced operation that compensates for the efficiency of replacement and saves energy as a whole.

In addition, since frost adheres to the cooler 32, defrost processing (energization of the defrost heater) is performed periodically (every fixed time). Based on the pressure and temperature detection signal of 37b, if the pressure drop and the refrigerant pipe temperature difference become 1 ° C or less and do not improve for a certain period of time, it is determined that excessive frosting is occurring, defrosting is performed forcibly, and the compressor is overheated. Suppress load operation.

After the cooling tube (cooler 32) has cooled to a certain extent, the cooling fan 33 after the defrost process is not driven to full rotation at once after a predetermined time after finishing the heating of the heater and passing the coolant as in the conventional device. , start at low speed rotation, and increase the rotation speed appropriately according to the passage of time, so that the warm air mass around the cooler 32 heated by the defrost heater 35 is slowly diffused into the freezer, and the entire inside of the freezer is rapidly An abnormal pressure rise is suppressed, and the pressure rise is dealt with by the intake/exhaust valve 12, so that an abnormal load is not applied to the wall panel or the opening/closing door.

As described above, in addition to the optimal control of the inverter refrigerator, it is possible to control the number of rotations of the cooling fan drive, making it possible to respond to operations in which the refrigeration capacity is adjusted over a wide range. It is. As a matter of course, it is necessary to adopt a control means that considers the order of priority of control methods so as not to duplicate the functions of the refrigerator and the expansion valve (particularly, the electronic expansion valve).

1 storage body 11 open/close door 12 pressure control valve (intake and exhaust valve)
13a, 13b, 13c, 13d inside temperature sensor 14 outside temperature sensor 2 outside refrigerator unit 21 outlet liquid tube pressure gauge 22 inlet liquid tube pressure gauge 3 inside cooling unit 31 electronic expansion valve 32 cooler (evaporator)
33 cooling fan 34 fan drive motor 35 defrost heaters 36a, 36b inlet/outlet pipe pressure gauges 37a, 37b inlet/outlet pipe thermometers 4 refrigerant pipe 41 electromagnetic on-off valve

Claims (4)

The main body of the warehouse, which is constructed with heat-insulating panels and has the shape of a warehouse, is equipped with an external refrigerator unit including an inverter compressor, a cooling fan and cooler installed inside the warehouse and driven by a variable speed motor, and a temperature expansion valve or an electronic A refrigerating cycle that circulates the refrigerant is connected to the internal cooling unit including the type expansion valve by a refrigerant pipe. and a warehouse-type refrigerator-refrigerator comprising a control unit that controls the driving of the refrigeration cycle, including stopping and controlling the rotation speed of the cooling fan,
When the internal temperature exceeds a preset upper limit temperature, the refrigerating cycle is activated. A warehouse-type freezer-refrigerator comprising control means for rotating the cooling fan outside the operating temperature range at a lower speed as the cooling load of the cooler increases. In the warehouse-type refrigerator-freezer according to claim 1,
When the cooling load of the cooler is determined based on the average temperature inside the refrigerator against the design evaporation temperature of the refrigerant, the rotation drive control of the cooling fan is in the range of 10 to 20% or less in the high temperature range where the average temperature inside the refrigerator is 30 ° C or higher. A warehouse-type freezer-refrigerator driven at 10°C or higher, driven at 50% or less at 10°C or higher, and driven at 100% at lower than 10°C. In addition to installing multiple internal temperature sensors at suitable locations, an open/close sensor is installed on the opening/closing door provided in the storage room, and the temperature sensor installed in the space near the opening/closing door detects the operation control standard of the cooling fan after opening/closing the door. 3. The warehouse-type freezer-refrigerator according to claim 2, which serves as data. A defrost heater is installed in the cooler, and after defrosting is performed at regular intervals and based on the refrigerant temperature and pressure detection, the cooling fan is started at a low speed after the cooler temperature drops, and the internal pressure is stabilized. 4. The warehouse-type refrigerator/freezer according to any one of claims 1 to 3, wherein control is performed to operate at a predetermined rotation later.

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