JP2011208893A - Cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a compressor to start safely and speedily upon reset of power supply due to an instantaneous service interruption without arranging a pressure sensor in particular.SOLUTION: A cooling device 10 with a refrigerating cycle consisting of the compressor 18, a radiator 19, an expansion valve 8, and an evaporator 11, includes a check valve 45 connected to the intake side of the compressor, an evaporator inlet temperature sensor 29, an evaporator outlet temperature sensor 30, a discharge gas temperature sensor 49 of the compressor, an outside air temperature sensor 48, and a control device 9 controlling the operation of the compressor. When power supply is switched on, the occurrence of the instantaneous service interruption is determined based on a plurality of conditions. When applicable, the start of the compressor 18 is delayed for time necessary for achieving equilibrium in a high/low pressure difference in the refrigerating cycle.

Description

  The present invention relates to a cooling device in which a refrigeration cycle is configured by a compressor, a radiator, a decompression device, and an evaporator, and more particularly to control at the time of restarting the compressor.

  Conventionally, for example, a commercial refrigerator or the like has been provided with a cooling device for cooling the inside of the refrigerator. This cooling device is provided with a refrigerant circuit formed by sequentially connecting a compressor, a radiator, a decompression device, an evaporator, and the like in an annular manner. When the compressor is operated, the refrigerant is sucked in from the low pressure side and compressed. Then, the high-temperature and high-pressure gas refrigerant discharged from the compressor flows into the radiator. The high-temperature and high-pressure gas refrigerant that has flowed into the radiator is dissipated and condensed into a condensate, and is then throttled by the expansion valve and flows into the evaporator where it evaporates. At that time, by absorbing heat from the surroundings, a cooling effect is exhibited, and a refrigeration cycle is again sucked from the low pressure side of the compressor.

  The compressor is started when the inside of the refrigerator reaches a predetermined upper limit temperature, and is operated in a cycle that is stopped when the interior of the refrigerator is lowered to a predetermined lower limit temperature by cooling with an evaporator. After the compressor is stopped, the pressure difference between the high pressure side and the low pressure side of the refrigerant circuit decreases with time, but when restarted immediately after the compressor stops, the high pressure side of the refrigerant circuit Since the pressure difference between the low pressure side and the low pressure side is still large, the compressor has to send more refrigerant to the high pressure state, and a great load is applied to the compressor.

  Since this overload causes winding burnout (winding burnout of the motor for driving the compressor), etc., when the overload is detected, the control device determines that the compressor has started, and determines that the start error has occurred. The compressor is prohibited from starting for a predetermined time.

  In addition, after plugging in a commercial refrigerator outlet and turning on the compressor, and after stopping during the compressor cycle operation, after turning on the power or shutting down the compressor so that the compressor does not start immediately. Thereafter, the predetermined time is regarded as a compressor start-up error (start-up delay time), and the start-up of the compressor is prohibited. Normally, the start-up error of the compressor is uniformly set to 3 to 5 minutes in order to ensure the time required for pressure equilibrium between the high pressure side and the low pressure side.

  Further, in this type of refrigerant circuit, when the compressor is stopped, warm refrigerant on the high pressure side naturally flows back to the evaporator, leading to an increase in the temperature of the evaporator. For this reason, a check valve is provided on the suction side of the compressor in order to eliminate the disadvantage that the warm refrigerant flows backward from the stopped compressor directly into the evaporator.

  In such a case, more time is required for the high-pressure side and the low-pressure side of the refrigerant circuit to be naturally balanced. Thus, after the compressor is stopped, it is necessary to make a start-up error for a predetermined time.

JP 2008-2441066 A

  However, there is a case where the power plug is disconnected from the outlet during the operation of the compressor or the thermo is turned off for some reason, or an instantaneous power failure due to the power supply system may occur. At this time, even if the power supply is immediately restored, the compressor is stopped because the power supply is once cut off. Therefore, immediately after the power is turned on, a compressor start error occurs, and the compressor cannot be started for a predetermined time.

  In this case, the inside of the refrigerator is cooled to a predetermined temperature by the operation of the cooling device so far. Here, even after the compressor is stopped, the compressor is forcibly set for a predetermined time, usually as described above, even if the low pressure side and the high pressure side of the compressor are actually balanced. Will stop for a set time of 3 to 5 minutes. Therefore, during that period, the cooling operation is not performed, which causes an increase in the temperature in the warehouse. Once the internal temperature rises and there is a large difference from the set temperature, it takes a long time to stabilize the internal temperature to the set temperature by pull-down operation when the compressor is restarted. Resulting in.

  The present invention has been made to solve the conventional technical problems, and without any special pressure sensor, the compressor can be started safely and quickly when power is restored due to an instantaneous power failure or the like. A cooling device is provided.

  In order to solve the above-mentioned problems, a cooling device according to the present invention includes a compressor, a radiator, a decompression device, and an evaporator, in which a refrigeration cycle is configured, and a check valve connected to the suction side of the compressor An evaporator inlet temperature sensor that detects the refrigerant inlet temperature ETI of the evaporator, an evaporator outlet temperature sensor that detects the refrigerant outlet temperature ETO of the evaporator, and a discharge gas temperature sensor that detects the discharge gas temperature DT of the compressor And an outside air temperature sensor that detects the outside air temperature AT, and a control device that controls the operation of the compressor based on the output of these temperature sensors. When the power is turned on, the control device The refrigerant inlet temperature ETI is not more than the set value A, the difference ETI-ETO between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the evaporator is not more than the set value B, and the discharge gas temperature DT is the outside air temperature AT + It is value C or more, if all conditions are met, the high-low pressure difference of the refrigerating cycle is characterized by a time delaying the start of the compressor required to equilibrate.

  The invention of claim 2 is a cooling device in which a refrigeration cycle is constituted by a compressor, a radiator, a decompression device, and an evaporator, a check valve connected to the suction side of the compressor, and a refrigerant inlet temperature ETI of the evaporator. An evaporator inlet temperature sensor that detects the refrigerant, an evaporator outlet temperature sensor that detects the refrigerant outlet temperature ETO of the evaporator, a discharge gas temperature sensor that detects the discharge gas temperature DT of the compressor, and an outside air that detects the outside air temperature AT A temperature sensor and a control device for controlling the operation of the compressor based on the output of the temperature sensor, and the control device is configured such that the refrigerant inlet temperature ETI of the evaporator is equal to or lower than a set value A during a thermocycle; The difference ETI−ETO between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the evaporator is not more than the set value B, and the discharge gas temperature DT is not less than the outside air temperature AT + set value C. If the condition is met, high-low pressure difference of the refrigerating cycle is characterized by a time delaying the start of the compressor required to equilibrate.

  The invention of claim 3 is characterized in that, in each of the above inventions, the set values A, B and C can be changed.

  The invention of claim 4 is characterized in that, in each of the above inventions, carbon dioxide is enclosed as a refrigerant in the refrigeration cycle.

  According to the present invention, in the cooling device in which the refrigeration cycle is configured by the compressor, the radiator, the decompression device, and the evaporator, the check valve connected to the suction side of the compressor and the refrigerant inlet temperature ETI of the evaporator An evaporator inlet temperature sensor to detect, an evaporator outlet temperature sensor to detect the refrigerant outlet temperature ETO of the evaporator, a discharge gas temperature sensor to detect the discharge gas temperature DT of the compressor, and an outside air temperature to detect the outside air temperature AT And a control device for controlling the operation of the compressor based on the outputs of the temperature sensors. The control device is configured such that the refrigerant inlet temperature ETI of the evaporator is equal to or lower than a set value A when the power is turned on. The difference ETI-ETO between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the evaporator is not more than the set value B, and the discharge gas temperature DT is not less than the outside air temperature AT + the set value C. If the condition of Te are met, the time required for the high-low pressure difference of the refrigerating cycle is balanced, by delaying the start of the compressor can be started safely and quickly compressor.

  In particular, in the present invention, when the power is turned on, the refrigerant inlet temperature ETI of the evaporator is equal to or lower than the set value A, and the difference ETI-ETO between the refrigerant inlet temperature ETI of the evaporator and the refrigerant outlet temperature ETO is set. When the cooling device is immediately after stopping from the condition that it is equal to or less than the value B, and from the condition that the discharge gas temperature DT is equal to or higher than the outside air temperature AT + the set value C, the compressor is operating until just before. In this case, the start-up of the compressor is delayed for a time required for the high / low pressure difference of the refrigeration cycle to be balanced.

  Therefore, when the power is turned on by turning on / off the power in a short time such as an instantaneous power failure, the refrigeration cycle does not go through a waiting time that is uniformly set as if a compressor startup error has occurred as in the past. The compressor can be started safely by delaying the minimum time required for the high and low pressure differentials to equilibrate.

  Therefore, in such a case, after the power is turned on, it is possible to effectively suppress an increase in the product temperature in the space to be cooled by the cooling device due to the elapse of the standby time due to the compressor start error, thereby realizing an appropriate cooling operation. It becomes possible.

  According to the invention of claim 2, in the cooling device in which the refrigeration cycle is constituted by the compressor, the radiator, the decompression device, and the evaporator, the check valve connected to the suction side of the compressor, and the refrigerant inlet of the evaporator An evaporator inlet temperature sensor that detects the temperature ETI, an evaporator outlet temperature sensor that detects the refrigerant outlet temperature ETO of the evaporator, a discharge gas temperature sensor that detects the discharge gas temperature DT of the compressor, and an outside air temperature AT And a control device that controls the operation of the compressor based on the outputs of these temperature sensors, and the control device has a refrigerant inlet temperature ETI of the evaporator that is equal to or lower than a set value A during a thermocycle. That is, the difference ETI−ETO between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the evaporator is not more than the set value B, and the discharge gas temperature DT is not less than the outside air temperature AT + the set value C. If all conditions are met, the time required for the high-low pressure difference of the refrigerating cycle is balanced, by delaying the start of the compressor can be started safely and quickly compressor.

  In particular, in the invention of claim 2, during the thermocycle, the refrigerant inlet temperature ETI of the evaporator is not more than the set value A, and the difference ETI-ETO between the refrigerant inlet temperature ETI of the evaporator and the refrigerant outlet temperature ETO is the set value. From the condition that the cooling device is immediately after stopping from the condition that it is B or less, and from the condition that the discharge gas temperature DT is equal to or higher than the outside air temperature AT + the set value C, the compressor has been operated until just before. In some cases, the start-up of the compressor is delayed for a time required for the high / low pressure difference of the refrigeration cycle to equilibrate.

  Therefore, at the time of the thermo-on, the minimum time necessary for the high-low pressure difference of the refrigeration cycle to be balanced is delayed without passing through the standby time that is uniformly set as if a compressor start-up error has occurred. Thus, the compressor can be started safely.

  Therefore, in such a case, it is possible to effectively suppress an increase in the product temperature in the space to be cooled by the cooling device due to the elapse of the standby time due to the compressor start error when the thermo is turned on, and realize an appropriate cooling operation. Is possible.

  Further, according to the invention of claim 3, in addition to the above-described inventions, the setting values A, B and C can be changed, so that each setting value can be appropriately selected according to the device and the use situation. , The convenience can be improved. In addition, an accurate compressor delay can be performed.

  According to the invention of claim 4, in each of the above inventions, since the carbon dioxide is sealed as a refrigerant in the refrigeration cycle, the pressure on the high-pressure side becomes higher and a compressor start error is likely to occur. In such a case, it becomes more advantageous to apply the above inventions.

It is a vertical side view of the freezer as an example which applies the present invention. It is a refrigerant circuit figure of the cooling device of the present invention. It is an electrical block diagram of a control apparatus. It is a flowchart of starting delay control of a compressor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1: has shown the vertical side view of the commercial freezer (low temperature storage) R as an Example which applies the cooling device 10 of this invention. The freezer R according to the embodiment is installed in a kitchen of a hotel or a restaurant, for example, and a main body is constituted by a heat insulating box 1 whose front opening 22 is closed by a door 6 so as to be freely opened and closed.

  The heat insulating box 1 is filled in an in-situ foaming manner between an outer box 2 made of a steel plate such as stainless steel, an inner box 3 incorporated in the outer box 2, and both inner and outer boxes 2, 3. It is made of polyurethane heat insulating material 4. And the inside of this heat insulation box 1 (inner box 3) is made into the storage room (space to be cooled) 5.

  A cooling chamber 14 to which the evaporator 11 of the cooling device 10 according to the present invention and the blower 12 for circulating cold air are attached is partitioned by a partition plate 13 in the upper part of the storage chamber 5. The cold air sucked into the cooling chamber 14 from the storage chamber 5 by the cool air circulation blower 12 is exchanged with the evaporator 11 and then discharged from the opening at the rear of the cooling chamber 14 so that the inside of the storage chamber 5 has a predetermined temperature. To be cooled.

  On the other hand, a machine room 17 is defined on the top surface of the heat insulation box 1 by a front panel 16 and panels constituting both side faces and a rear face, and a compressor 18 constituting the cooling device 10 is formed in the machine room 17. And a radiator 19 are installed, and together with the evaporator 11, a known refrigeration cycle of the cooling device 10 is configured. Reference numeral 20 denotes a radiator blower.

  Here, the refrigerant circuit 7 of the cooling device 10 in the present embodiment will be described with reference to the refrigerant circuit diagram of FIG. In the refrigeration cycle of the cooling device 10 in the present embodiment, carbon dioxide is enclosed as a refrigerant, and a split cycle (two-stage compression one stage) in which the refrigerant pressure (high pressure) on the high pressure side is equal to or higher than the critical pressure (supercritical). Adopt expansion intercooling cycle).

  The cooling device 10 of this embodiment includes a low-stage compression element (low-stage compression means) 18A that constitutes the compressor (compression means) 18 and a high-stage compression element (high-stage) that also constitutes the compression means. Side compression means) 18B, the radiator 19, the flow divider 37, the merger 38, the auxiliary expansion valve 39 as an auxiliary pressure reducing device, the intermediate heat exchanger 40, the internal heat exchanger 41, and the main pressure reducing device. The refrigerant circuit 7 is composed of the expansion valve 8 and the evaporator 11.

  The radiator 19 cools the refrigerant discharged from the high-stage compression element 18B by radiating the high-temperature and high-pressure refrigerant discharged from the high-stage compression element 18B. In the present embodiment, the radiator 19 is constituted by a gas cooler heat exchanger. The flow divider 37 divides the refrigerant from the radiator 19 into a first refrigerant flow and a second refrigerant flow, flows the first refrigerant flow to the sub circuit 42, and sends the second refrigerant flow to the main circuit 43. Shed.

  In the main circuit 43 in FIG. 2, the refrigerant divided by the flow divider 37 is the inner pipe 40B of the intermediate heat exchanger 40, the inner pipe 41B of the internal heat exchanger 41, the strainer 44, the expansion valve 8, the evaporator 11, The external heat pipe 41A of the internal heat exchanger 41, the check valve 45, and the strainer 46 are sequentially connected so as to be supplied to the suction side of the compression element 18A constituting the low-stage compression means. The sub-circuit 42 sucks the compression element 18B that constitutes the high-stage compression means, in which the refrigerant divided by the flow divider 37 sequentially passes through the strainer 47, the auxiliary expansion valve 39, and the outer pipe 40A of the intermediate heat exchanger 40. It is connected so that it may be supplied to the side.

  The compressor 18 in the present embodiment includes an internal intermediate pressure two-stage compression in which a compression element 18A as a low-stage compression means and a compression element 18B as a high-stage compression means are accommodated in a single sealed container. A rotary compressor is used. These compression elements 18A and 18B are driven by a compressor motor (electric element, DC motor) housed in the same sealed container.

  On the suction side of the low-stage compression element 18A, a check valve 45 and a refrigerant introduction pipe 23 into which the refrigerant flowing out from the strainer 46 is introduced are connected, and the refrigerant taken into the low-stage compression element 18A. Is increased to an intermediate pressure here. The refrigerant compressed by the low-stage compression element 18A is discharged into a sealed container through a communication pipe (not shown). A sub-circuit 42 is connected to the sealed container via a merger 38.

  On the suction side of the high-stage compression element 18B, a refrigerant introduction pipe having one end opened in the hermetic container is provided, and the refrigerant boosted to the intermediate pressure by the low-stage compression element 18A and the intermediate from the sub circuit 42 are provided. The refrigerant mixed with the pressure refrigerant flows into the high-stage compression element 18B from the refrigerant introduction pipe, and is further pressurized to a predetermined high pressure. At this time, the refrigerant compressed by the high-stage compression element 18 </ b> B is brought into a supercritical state and flows into the radiator 19 through the refrigerant discharge pipe 24. In the present embodiment, the compression elements 18A and 18B constituting the compressor 18 are integrally coupled by a single motor, but the present invention is not limited to this.

  The refrigerant exiting the radiator 19 is cooled in the process of passing, and then enters the flow divider 37 and is divided into the sub circuit 42 through which the first refrigerant flow flows and the main circuit 43 through which the second refrigerant flow flows. . One refrigerant flow (first refrigerant flow) divided by the flow divider 37 enters the sub-circuit 42 and is at the intermediate expansion pressure (that is, the discharge pressure of the low-stage compression element 18A) by the auxiliary expansion valve 39. The pressure is reduced to substantially the same pressure as the suction pressure of the side compression element 18B. Then, in the process of passing through the outer pipe 40A of the intermediate heat exchanger 40 and passing through the outer pipe 40A, the second refrigerant flow after being branched by the flow divider 37 passing through the inner pipe 40B. It evaporates by exchanging heat with the refrigerant flow. Thereafter, the merger 38 joins the second refrigerant flow after being compressed by the low-stage compression element 18A, and is sucked into the high-stage compression element 18B.

  On the other hand, the other refrigerant flow (second refrigerant flow) divided by the flow divider 37 enters the main circuit 43 and is reduced in pressure by the auxiliary expansion valve 39 in the process of passing through the inner pipe 40B of the intermediate heat exchanger 40. After being cooled by exchanging heat with the first refrigerant flow, it passes through the inner pipe 41B of the internal heat exchanger 41. In the process of passing through the inner pipe 41B, the refrigerant is cooled by exchanging heat with the refrigerant flowing out of the evaporator 11 flowing in the outer pipe 41A.

  The first refrigerant flow that has flowed out of the internal heat exchanger 40 is decompressed to the evaporation pressure by the expansion valve 8, and then flows into the evaporator 11 and uses the inside of the storage chamber 5 (cooled space) as a heat source. It evaporates and returns to the compression element 18 on the lower stage side through the outer tube 41A of the internal heat exchanger 41. The internal heat exchanger 41 improves the cooling performance by exchanging heat between the refrigerant flowing into the expansion valve 8 and the low-temperature refrigerant flowing out from the evaporator 11.

  Thus, the cooling device 10 of the present embodiment uses natural carbon as a refrigerant, and uses carbon dioxide having a low critical pressure and a supercritical state of the refrigerant cycle at a high pressure. For this reason, it is possible to reduce the load on the environment and to secure the cooling capacity. In addition, the second refrigerant flow that flows through the other divided main circuit 43 is divided by the first refrigerant flow that flows through one of the sub-circuits 42 that has been cooled by the radiator 19 and is divided and decompressed and expanded. By using a so-called split cycle cooling device for cooling, the specific enthalpy at the inlet of the evaporator 11 can be reduced and the refrigeration effect can be increased.

  Thus, when the cooling device 10 is operated, the cold air heat-exchanged with the evaporator 11 in the cooling chamber 14 is discharged into the storage chamber 5 by the cool air circulation blower 12 and circulated in the storage chamber 5. Then, circulation that returns to the cooling chamber 14 by the blower 12 is performed again.

  Next, the control device 9 in the present embodiment will be described with reference to FIG. The control device 9 is configured by a general-purpose microcomputer and controls the cooling device 10. The control device 9 includes a timer 32 as a time limit means, an arithmetic processing unit 33, and a storage unit 34.

  A control panel 35 having various setting switches and a display unit is connected to the control device 9. The various setting switches include an LCD panel (setting means) 36 that can arbitrarily set each setting value as will be described in detail later.

  Further, on the input side of the control device 9, an in-compartment temperature sensor (current temperature detection means) 31 that detects the current temperature in the storage, and an evaporator inlet temperature sensor for detecting the refrigerant inlet temperature ETI of the evaporator 11. 29, the evaporator outlet temperature sensor 30 for detecting the refrigerant outlet temperature ETO of the evaporator 11, the temperature of the discharge gas temperature DT of the compressor 18 (actually, the discharge pipe (refrigerant discharge pipe) 24 of the compressor 18) The discharge gas temperature sensor 49 for detecting the outside air temperature, the outside air temperature sensor 48 for detecting the outside air temperature AT, and the like are connected.

  Here, the internal temperature sensor 31 is provided, for example, in the vicinity of the cold air inlet of the partition plate 13, measures the temperature in the storage chamber 5 after the cold air passes through the evaporator 11, and stores this. This is handled as the current temperature, which is the temperature in the chamber 5.

  On the other hand, on the output side of the control device 9, a compressor motor (DC motor) 18M that drives the compressor 18, a blower motor 12M that drives the blower 12 for circulating cold air, a blower motor 20M that drives the blower 20 for radiator, The expansion valve 8, the auxiliary expansion valve 39, etc. are connected. Here, the compressor motor 18M is connected via the inverter device 25, and thereby the frequency of the power source is changed, and the amount of compression of the refrigerant in the compressor 18 is changed by changing the rotation speed of the compressor motor 18M. Can be changed. The blower motors 12M and 20M are connected to each other via drive circuits 26 and 27 such as a chopper circuit, whereby the rotational speed can be arbitrarily changed. And based on each output mentioned above, the control apparatus 9 controls the opening degree of the expansion valve 8, and controls the rotation speed of each motor 18M, 12M, and 20M.

  As a result, the control device 9 sets the current temperature inside the compartment detected by the inside temperature sensor 31 as the cooling target temperature, and the degree of superheat in the evaporator 11 (the evaporator inlet side temperature and the evaporator outlet side). The operation frequency control of the compressor motor 18M and the opening degree control of the expansion valve 8 are performed so that the difference from the temperature becomes a predetermined appropriate value. When the current internal temperature detected by the internal temperature sensor 31 reaches the upper limit temperature higher than the cooling target temperature by the control device 9 in addition to the frequency control of the compressor 18, the control motor 18M When a lower limit temperature lower than the target cooling temperature by a predetermined temperature is reached, a thermocycle for stopping the compressor motor 18M is performed to control the internal temperature to the target cooling temperature.

  With the above configuration, the startup delay control of the compressor 18 of the freezer R in the present embodiment will be described with reference to the flowchart of FIG. First, at step S1, when the power is turned on by the user, the control device 9 prohibits the operation of the compressor 18 during a startup delay time, which will be described in detail later. In other words, the control device 9 does not immediately operate the compressor 18 when the power is turned on.

  Then, the control device 9 proceeds to step S2, and returns to the origin (initial operation) of each actuator, that is, resets all, and then proceeds to step S3. In step S3, the control device 9 determines whether or not the power supply is instantaneously interrupted, that is, whether there is an instantaneous power failure, a situation where the power supply plug is unplugged from the outlet when the cooling operation is being performed, and is immediately turned on again. Make a decision.

  In the present invention, the determination as to whether or not the power is turned on in step S3 is due to a momentary interruption based on the first to third conditions. The first condition is that the refrigerant inlet temperature ETI of the evaporator 18 is equal to or lower than the set value A, and the second condition is that the difference ETI-ETO between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the evaporator 18 is set. The third condition is that the discharge gas temperature DT is equal to or greater than the outside air temperature AT + the set value C.

  The first condition is to determine whether or not the cooling device 10 has been operated from the refrigerant inlet temperature ETI of the evaporator 18 until just before the power is turned on. That is, immediately after the power is turned on, the evaporator inlet temperature ETI has not yet been affected so much by the outside air temperature, and thus is as low as in the cooling operation. Therefore, the set value A is set to a slightly higher temperature (a temperature higher by a predetermined value) than the evaporator inlet temperature ETI during the cooling operation. When the evaporator inlet temperature ETI is equal to or lower than the set value A, the control device 9 can be a material that determines that the cooling device 10 would have been operated until just before the power was turned on.

  The second condition is to determine the state of the evaporator 18 from the difference between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the evaporator 18. Here, the temperature change based on the operating condition of the compressor 18 of the evaporator 11 will be described. When the compressor 18 is in operation, the control device 9 detects the refrigerant inlet temperature ETI of the evaporator 11 detected by the evaporator inlet temperature sensor 29 and the refrigerant of the evaporator 11 detected by the evaporator outlet temperature sensor 30. Based on the output of the outlet temperature ETO, the opening degree of the expansion valve 8 is controlled so that the superheat degree of the refrigerant in the evaporator 11 becomes an appropriate value. Therefore, the evaporator outlet temperature ETO is higher than the evaporator inlet temperature ETI by the degree of superheat (ETI <ETO).

  Immediately after the compressor 18 stops, the refrigerant flow into the evaporator 11 stops, so that the refrigerant temperature in the evaporator 11 is balanced, and the difference between the evaporator inlet temperature ETI and the evaporator outlet temperature ETO is predetermined. Below the value, that is, almost in an equilibrium state (ETI≈ETO).

  After that, a check valve 45 having a forward direction from the evaporator 18 toward the compressor 18 is provided on the suction side of the compressor 18, so that when the compressor 18 is stopped, the discharge side of the compressor 18 is stopped. The hot gas refrigerant flowing out of the refrigerant flows into the evaporator 11 only from the inlet side of the evaporator 11. Therefore, contrary to the cooling operation, the evaporator inlet temperature ETI is higher than the evaporator outlet temperature ETO (ETI> ETO).

  Further, as time elapses, the influence of the hot gas flowing into the evaporator 11 is alleviated, and the difference between the evaporator inlet temperature ETI and the evaporator outlet temperature ETO is equal to or less than a predetermined value, that is, almost in an equilibrium state. (ETI≈ETO).

  Therefore, the set value B in the second condition is a value that can be determined to be before the temperature rise due to the inflow of hot gas refrigerant that has flowed out due to the stop of the compressor 18 from the inlet side of the evaporator 11, that is, evaporation. The refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the vessel 18 are set to values that can be judged as being in equilibrium (difference ETI-ETO is zero) or approximate to the equilibrium state (difference ETI-ETO is a small value). . When the difference ETI-ETO between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO is equal to or less than the set value B, the control device 9 may be a material that determines that the cooling device 10 would have been operated until just before the power was turned on. it can.

  As described above, whether the cooling device 10 is operated from the first condition and the second condition until immediately before the power is turned on, so that the pressure difference between the high pressure side and the low pressure side of the refrigerant circuit is still large. It can be determined whether or not.

  The third condition is to determine whether or not the compressor 18 has been operated from the discharge gas temperature (discharge pipe temperature) DT of the compressor 18 to immediately before the power is turned on. Only the first condition and the second condition satisfy the first condition when the outside air temperature AT is extremely low, and the temperature of the evaporator substantially equilibrates with the outside air temperature after the cooling device 10 is stopped. In the case of reaching the level, the difference ETI-ETO becomes equal to or less than the set value B, which satisfies the second condition.

  On the other hand, if the compressor 18 was operated immediately before the power was turned on, the discharge gas temperature (discharge pipe temperature) DT is expected to be considerably higher than the outside air temperature AT. Therefore, by adding the set value C to the outside air temperature AT, a value that can determine whether or not the compressor 18 has been operated is set. Thereby, the control device 9 can determine that the compressor 18 has been operated until immediately before the power is turned on, when the discharge gas temperature (temperature of the discharge side pipe) DT is higher than the outside air temperature AT by the set value C or more. .

  And the control apparatus 9 progresses to step S4, when all said 1st thru | or 3rd conditions are satisfy | filled in step S3. In step S4, the control device 9 determines whether or not a time required for balancing the pressure difference between the high pressure side and the low pressure side of the refrigeration cycle (compressor startup error avoidance delay time), for example, 50 seconds has elapsed. to decide.

  After the compressor activation error avoidance delay time has elapsed, the control device 9 proceeds to step S5 and activates the compressor 18.

  As described above, in the present invention, whether or not the cooling device 10 has been operated immediately before the power is turned on is determined based on all the first to third conditions, and if this is satisfied, the high-low pressure difference of the refrigeration cycle is balanced. By delaying the start of the compressor 18 for a necessary time, the compressor 18 can be started safely and quickly.

  In particular, in this embodiment, as described above, when the power is turned on, the refrigerant inlet temperature ETI of the evaporator 11 is not more than the set value A (first condition), and the refrigerant inlet temperature of the evaporator 11 is set. Based on the condition that the difference ETI-ETO between the ETI and the refrigerant outlet temperature ETO is equal to or less than the set value B (second condition), the discharge gas temperature DT is outside air when the cooling device 10 is immediately after stopping. When the compressor 18 has been operated just before from the condition that the temperature AT + the set value C or higher (third condition), the time required for the high / low pressure difference of the refrigeration cycle to equilibrate, Delay startup.

  Therefore, when the power is turned on by turning on / off the power in a short time such as an instantaneous power failure, it is assumed that a compressor start-up error has occurred as in the conventional case, and a uniformly set waiting time (3 minutes to 5 in the past). The minimum time required for the high / low pressure difference of the refrigeration cycle to equilibrate is delayed without passing through the set time of minutes) and without any special pressure detection means. Can be activated.

  Therefore, in such a case, after the power is turned on, it is possible to effectively suppress an increase in the product temperature in the space to be cooled by the cooling device due to the elapse of the standby time due to the compressor start error, thereby realizing an appropriate cooling operation. It becomes possible.

  In the above description, the setting value A, the setting value B, the setting value C, and the compressor start error avoidance delay time can be arbitrarily changed by the LCD panel 36 of the control panel 35. Therefore, each set value can be selected as appropriate according to the device and usage status, and convenience can be improved. In addition, it is possible to accurately delay the compressor 18.

  On the other hand, when the control device 9 determines in step S3 that all of the first to third conditions are not satisfied, the control device 9 proceeds to step S5 and sets the compressor start error avoidance delay time. The compressor 18 is started without waiting for progress.

  On the other hand, when the thermocycle of the compressor 18 as described above is being executed, when the internal temperature reaches the predetermined upper limit temperature and the thermo-on signal is issued from the state where the compressor 18 is stopped (step S6). Then, the control device 9 proceeds to step S7, and determines whether or not a predetermined compressor delay time has elapsed since the previous compressor 18 stopped operating. The compressor delay time is uniformly set to 3 to 5 minutes in order to ensure the time required for the pressure equilibrium between the high pressure side and the low pressure side.

  Then, after the compressor delay time has elapsed, the control device 9 proceeds to step S3 as described above, and determines whether the compressor start error avoidance delay condition is satisfied based on the first to third conditions. That is, whether or not the cooling device 10 is operated from the first condition and the second condition until just before the thermo-on state, so that the pressure difference between the high pressure side and the low pressure side of the refrigerant circuit is still large. Determine. Based on the third condition, it is determined whether or not the compressor 18 has been operated from the discharge gas temperature (temperature of the discharge side pipe) DT of the compressor 18 to just before the thermo-on.

  Then, when all the first to third conditions are satisfied in step S3, the control device 9 proceeds to step S4, and the pressure difference between the high pressure side and the low pressure side of the refrigeration cycle is balanced. It is determined whether a necessary time (compressor activation error avoidance delay time), for example, 50 seconds has elapsed. After the compressor activation error avoidance delay time has elapsed, the control device 9 proceeds to step S5 and activates the compressor 18.

  As described above, in the present invention, it is determined whether or not the cooling device 10 has been operated immediately before the thermo-ON, and all the first to third conditions are determined. By delaying the start of the compressor 18 for a necessary time, the compressor 18 can be started safely and quickly.

  In particular, in this embodiment, when the power is turned on, the refrigerant inlet temperature ETI of the evaporator 11 is not more than the set value A (first condition), the refrigerant inlet temperature ETI of the evaporator 11 and the refrigerant outlet temperature. Based on the condition that the difference ETI-ETO from the ETO is equal to or less than the set value B (second condition), the discharge gas temperature DT is set to the outside air temperature AT + set value C when the cooling device 10 is immediately after stopping. From the above condition (third condition), when the compressor 18 has been operated until just before, the start-up of the compressor 18 is delayed for a time required for the high / low pressure difference of the refrigeration cycle to be balanced.

  Therefore, based on the first to third conditions, it is appropriately determined whether or not the difference between the high and low pressures of the refrigerant circuit is still large without providing any special pressure detection means. The compressor 18 can be started safely by delaying the minimum time required for the high and low pressure differentials to equilibrate.

  Accordingly, when starting the compressor 18 when the thermo is on, a compressor start error occurs, so that it is possible to avoid the inconvenience of waiting for the compressor start error waiting time to elapse. Thereby, it becomes possible to effectively suppress an increase in the product temperature in the space to be cooled by the cooling device, and it is possible to realize an appropriate cooling operation.

  In the above description, the setting value A, the setting value B, the setting value C, and the compressor start error avoidance delay time can be arbitrarily changed by the LCD panel 36 of the control panel 35. Therefore, each set value can be selected as appropriate according to the device and usage status, and convenience can be improved. In addition, it is possible to accurately delay the compressor 18.

  On the other hand, when the control device 9 determines in step S3 that all of the first to third conditions are not satisfied, the control device 9 proceeds to step S5 and sets the compressor start error avoidance delay time. The compressor 18 is started without waiting for progress.

  As in the present embodiment, when carbon dioxide is enclosed as a refrigerant in the refrigeration cycle, it is necessary to set the condensation pressure high due to the evaporation temperature and the characteristics of the refrigerant and equipment. Further, a check valve 45 is provided on the suction side of the compressor 18 in order to prevent the temperature in the storage chamber 5 from rising as much as possible when the thermo-cycle of the cooling device 10 is turned off. Therefore, compared to the case where other refrigerants are used, after the compressor 18 is stopped, it takes a longer time for the pressure on the high-pressure side and the low-pressure side of the refrigeration cycle to equilibrate, so that a compressor start error is likely to occur. However, in such a case, it is more advantageous to apply the above inventions.

R Commercial freezer (low temperature storage)
1 Insulation box 5 Storage room (cooled space)
7 Refrigerant circuit 8 Expansion valve (main decompression device)
DESCRIPTION OF SYMBOLS 9 Control apparatus 10 Cooling apparatus 11 Evaporator 18 Compressor 19 Radiator 23 Refrigerant introduction pipe 24 Refrigerant discharge pipe 29 Evaporator inlet temperature sensor 30 Evaporator outlet temperature sensor 32 Timer (time limit means)
35 Control panel 36 LCD panel (setting means)
45 Check valve 48 Outside temperature sensor 49 Discharge gas temperature sensor

Claims (4)

In the cooling device in which the refrigeration cycle is composed of a compressor, a radiator, a decompressor, and an evaporator,
A check valve connected to the suction side of the compressor;
An evaporator inlet temperature sensor for detecting the refrigerant inlet temperature ETI of the evaporator;
An evaporator outlet temperature sensor for detecting a refrigerant outlet temperature ETO of the evaporator;
A discharge gas temperature sensor for detecting a discharge gas temperature DT of the compressor;
An outside air temperature sensor for detecting the outside air temperature AT;
A control device for controlling the operation of the compressor based on the output of these temperature sensors,
When the control device is turned on,
The refrigerant inlet temperature ETI of the evaporator is not more than a set value A;
The difference ETI-ETO between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the evaporator is not more than a set value B, and
The discharge gas temperature DT is not less than the outside air temperature AT + set value C;
When all of the above conditions are satisfied, the cooling device is characterized in that the start-up of the compressor is delayed for a time required for the high-low pressure difference of the refrigeration cycle to be balanced. In the cooling device in which the refrigeration cycle is composed of a compressor, a radiator, a decompressor, and an evaporator,
A check valve connected to the suction side of the compressor;
An evaporator inlet temperature sensor for detecting the refrigerant inlet temperature ETI of the evaporator;
An evaporator outlet temperature sensor for detecting a refrigerant outlet temperature ETO of the evaporator;
A discharge gas temperature sensor for detecting a discharge gas temperature DT of the compressor;
An outside air temperature sensor for detecting the outside air temperature AT;
A control device for controlling the operation of the compressor based on the output of these temperature sensors,
The controller is in a thermocycle
The refrigerant inlet temperature ETI of the evaporator is not more than a set value A;
The difference ETI-ETO between the refrigerant inlet temperature ETI and the refrigerant outlet temperature ETO of the evaporator is not more than a set value B, and
The discharge gas temperature DT is not less than the outside air temperature AT + set value C;
When all of the above conditions are satisfied, the cooling device is characterized in that the start-up of the compressor is delayed for a time required for the high-low pressure difference of the refrigeration cycle to be balanced.   The cooling device according to claim 1 or 2, wherein the set values A, B, and C can be changed.   4. The cooling apparatus according to claim 1, wherein carbon dioxide is sealed as a refrigerant in the refrigeration cycle.

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