JP2006132800A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly efficient refrigerating cycle device that arranges a decompression means under a frost formation environment and can easily melt frost adhering to this decompression means. <P>SOLUTION: The refrigerating cycle device comprises a compressor 10 for compressing at least a refrigerant to a high temperature and high pressure and delivering it, a radiator 20 for radiating the refrigerant compressed by the compressor, a decompression means 40 having an electric drive section for decompressing the refrigerant heat-dissipated by the radiator, an evaporator 30 for evaporating the refrigerant decompressed by the decompression means, and a defrosting means 60 for defrosting frost adhering to the evaporator. The decompression means 40 is arranged under the frost formation environment, and the electric drive section is energized to melt the frost adhering to the decompression means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a refrigeration cycle apparatus. More specifically, the present invention relates to a refrigeration cycle apparatus in which decompression means such as an expansion valve is disposed in a frosting environment.

  In a refrigeration cycle apparatus that operates in a temperature range where frost formation occurs, defrosting is essential to maintain the refrigeration capacity. In particular, frost formation on the evaporator causes a significant decrease in refrigeration capacity, so some defrosting means is constructed.

  For example, the method of defrosting by directly heating the evaporator using an electric heater, hot gas defrosting in which the high-temperature and high-pressure refrigerant at the compressor outlet directly flows into the evaporator, or the operation of the refrigeration cycle is stopped. Various defrosting methods have been proposed, such as off-cycle defrosting in which defrosting is performed by flowing only the wind through the evaporator (see, for example, Patent Document 1).

  By the way, in order to further increase the efficiency of the refrigeration cycle, reducing the heat absorption loss caused by placing decompression means such as expansion valves and ejectors in a frosting environment near the evaporator and placing them in a room temperature environment. It is desirable to do. However, due to the following problems, it has been difficult to mount these decompression means in a frost environment.

For example, when an electric heater is applied to the defrosting of the evaporator, even if the defrosting of the evaporator is completed, the electric heater is lengthened until the defrosting of the decompression means configured farther than the evaporator is completed. There is a problem that it must be operated for a long time and the internal temperature rises, so that the refrigeration load increases or the temperature of the internal contents increases. Further, when defrosting the evaporator with hot gas, the hot gas bypasses the decompression means and is directly supplied to the evaporator, so it is difficult to defrost the bypassing decompression means. . Furthermore, in the case of off-cycle defrosting, the decompression means has a large heat capacity and requires a considerably long time for defrosting compared to the evaporator, so an increase in the internal temperature is inevitable. In addition, although it is possible to cope with the depressurization means by configuring a dedicated defrosting electric heater, there is a problem that the configuration is complicated and the cost is increased. For this reason, when a decompression means is arranged in a frosting environment in a conventional refrigeration cycle, a method of using an orifice or the like that hardly frosts may be employed as the decompression means. However, in such a pressure reducing means, a performance reduction of the refrigeration cycle due to the fixed throttle is unavoidable as compared with a variable throttle whose opening degree can be adjusted according to the refrigeration load of the system. In particular, in an ejector cycle that uses an ejector as a decompression means, the ejector is constituted by a nozzle, a mixing unit, and a diffuser unit, and thus has a larger heat capacity than a normal expansion valve, which is more disadvantageous for defrosting. In addition, since it is possible to guide more liquid refrigerant to the evaporator by the ejector cycle, lowering the evaporation temperature in the evaporator to achieve a low internal temperature and improving the refrigerating capacity and COP, etc. However, there is also a problem that frost formation becomes easier.
JP 57-47829 A

  The present invention has been made in view of the above circumstances, and provides a highly efficient refrigeration cycle apparatus in which decompression means is arranged in a frosting environment and frost adhering to the decompression means can be easily melted. Let it be an issue.

  The inventors use a decompression unit having an electric drive unit that is driven by electric energy. When the refrigeration cycle is energized and applied to the electric drive unit when the refrigeration cycle is in a defrosting operation, the coil in the drive unit generates heat. It is thought that the decompression means transmitted to the valve part of the decompression means and frosted during the refrigeration operation can be defrosted with a simple configuration and can be defrosted without a decrease in refrigeration performance such as an increase in the defrost time. completed.

  The refrigeration cycle apparatus of the present invention has at least a compressor that compresses and discharges a refrigerant at high temperature and high pressure, a radiator that dissipates the refrigerant compressed by the compressor, and an electric drive unit that uses electric energy as drive energy. In a refrigeration cycle apparatus having a decompression means for decompressing a refrigerant radiated by a radiator, an evaporator for evaporating the refrigerant decompressed by the decompression means, and a defrosting means for defrosting frost adhering to the evaporator The decompression unit is disposed in a frosting environment, and the electric drive unit is energized to melt frost attached to the decompression unit.

  Since the refrigeration cycle apparatus of the present invention uses a decompression unit having an electric drive unit, the frost attached to the decompression unit can be easily melted by energizing (exciting) the electric drive unit even in a frosting environment. It is possible to prevent a decrease in performance of the refrigeration cycle apparatus due to frost formation.

  In the refrigeration cycle apparatus according to the present invention, the defrosting means bypasses the refrigerant discharged from the compressor and bypasses the decompression means to guide the evaporator, and during normal operation, the refrigerant flows into the hot gas passage. It is desirable to provide inflow prevention means for preventing. With the defrosting means having such a configuration, the defrosting of the evaporator can be performed easily and reliably.

  In the refrigeration cycle apparatus of the present invention, the decompression means converts the pressure energy of the high-pressure refrigerant flowing out of the radiator into velocity energy and decompresses and expands the refrigerant, and an electric drive that variably controls the throttle opening of the nozzle The gas-phase refrigerant evaporated in the evaporator is sucked by the high-speed refrigerant flow injected from the nozzle and the nozzle, and the velocity energy is converted to pressure energy while mixing the refrigerant injected from the nozzle and the refrigerant sucked from the evaporator It is preferable that the ejector has a diffuser for increasing the pressure of the refrigerant. By using the ejector having the above configuration as the decompression means, a highly efficient refrigeration cycle apparatus can be obtained.

  In the refrigeration cycle apparatus of the present invention, it is preferable that the decompression means is an electrically controlled expansion valve that electrically controls the flow rate of the refrigerant by an electric drive unit. Since finer control is possible by electrically controlling the refrigerant flow rate, a highly efficient refrigeration cycle apparatus can be obtained.

  In the refrigeration cycle apparatus of the present invention, it is desirable that the electric drive unit of the decompression means includes any of a stepping motor, a DC motor, or an AC motor. By providing such an electric drive unit, energization can cause the electric drive unit to generate heat and melt frost attached to the decompression means.

  Here, it is desirable to control the energization of the frosted decompression means with a pulse wave, a rectangular wave, a DC voltage or an AC voltage. By such an energization method, frost adhering to the decompression means can be efficiently and reliably melted.

  A preferred embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
The first embodiment is an ejector cycle in which the refrigeration cycle apparatus according to the present invention is applied to a vehicle air conditioner using chlorofluorocarbon as a refrigerant, and an ejector is used as a decompression means. FIG. 1 is a schematic diagram showing the outline.

  Reference numeral 10 denotes a compressor that obtains driving force from a driving source (not shown) such as a traveling engine and sucks and compresses the refrigerant. Reference numeral 20 denotes heat exchange between the refrigerant discharged from the compressor 10 and outdoor air. It is a radiator that cools. The compressor 10 according to the present embodiment employs a variable displacement compressor whose discharge flow rate (discharge capacity) is controlled so that the temperature of the refrigerant sucked into the compressor 10 becomes a predetermined temperature. Yes.

  Reference numeral 30 denotes an evaporator which exhibits a refrigerating capacity by exchanging heat between the air blown into the vehicle compartment and the liquid refrigerant and evaporating the liquid refrigerant, and 40 is evaporated by decompressing and expanding the refrigerant flowing out of the radiator 20. This is an ejector that sucks the vapor-phase refrigerant evaporated in the vessel 30 and converts the expansion energy into pressure energy to increase the suction pressure of the compressor 10.

  In addition, 31 is a drain pan which collects the condensed water which generate | occur | produced in the evaporator 30, or the molten water which generate | occur | produced at the time of the defrost operation mentioned later, and this drain pan 31 is normally provided in the downward side of the evaporator 30. FIG.

  Further, as shown in FIG. 2, the ejector 40 is configured to convert the pressure energy of the high-pressure refrigerant that flows into velocity energy to decompress and expand the refrigerant in an isentropic manner, and the high-speed refrigerant flow injected from the nozzle 41. A mixing unit 43 that mixes the gas-phase refrigerant evaporated in the evaporator 30 by the entrainment action and the refrigerant ejected from the nozzle 41, and a diffuser (pressure increasing unit) 44 that converts the velocity energy of the refrigerant at the mixing unit outlet into pressure energy to increase the pressure. Etc.

  Here, the throttle opening degree of the nozzle 41 is variably controlled by displacing the needle 45 in the axial direction of the nozzle 41 within the nozzle 41 by an actuator (electric drive unit) 46. In the present embodiment, an electric actuator such as a stepping motor using a screw mechanism is employed as the actuator 46.

  In FIG. 1, reference numeral 50 denotes a gas-liquid separator that stores the refrigerant by flowing the refrigerant flowing out of the ejector 40 into the vapor phase liquid and the liquid phase refrigerant and storing the refrigerant. The phase refrigerant is sucked into the compressor 10 and the separated liquid refrigerant is sucked into the evaporator 30 side.

  The refrigerant 60 discharged from the compressor 10 bypasses the radiator 20 and the ejector 40 and is guided to the refrigerant inlet side of the evaporator 30 (the refrigerant passage (refrigerant pipe 51) connecting the evaporator 30 and the gas-liquid separator 50). This is a hot gas passage (hot gas piping), and the hot gas passage 60 is configured to pass through the drain pan 31.

  A defrosting control valve (solenoid valve) 61 for opening and closing the hot gas passage 60 is provided on the compressor 10 side of the hot gas passage 60 from the drain pan 31, and the evaporator 30 from the drain pan 31 of the hot gas passage 60 is provided. On the side, a first check valve (inflow prevention means) 62 that allows the refrigerant to flow only from the compressor 10 side toward the evaporator 30 (refrigerant passage 51) side is provided. A second check valve that allows the refrigerant to flow only from the gas-liquid separator 50 side to the evaporator 30 side from the junction of the hot gas passage 60 and the refrigerant passage 51 to the gas-liquid separator 50 side. 52 is provided. In the refrigeration cycle apparatus of FIG. 1, a range F surrounded by a broken line including the evaporator 30, the ejector 40, and the gas-liquid separator 50 is a frosting environment.

  Next, the operation of the above-described refrigeration cycle apparatus (in the present embodiment, a vehicle-mounted refrigerator) will be described.

  First, during a normal operation (refrigeration operation) in which the evaporator 30 evaporates the refrigerant, the compressor 10 is activated and discharged from the compressor 10 to circulate the refrigerant to the radiator 20 side. Thereby, the refrigerant cooled (condensed) by the radiator 20 is decompressed and expanded by the nozzle 41 of the ejector 40 and sucks the refrigerant in the evaporator 30, and the compressor 10 is supplied from the gas-liquid separator 50 to the gas phase. Aspirate the refrigerant.

  On the other hand, since the refrigerant in the evaporator 30 is sucked by the ejector 40, the liquid-phase refrigerant flows from the gas-liquid separator 50 into the evaporator 30, and the refrigerant that has flowed in absorbs heat from the air blown into the room and evaporates. To do.

  The refrigerant sucked from the evaporator 30 (suction flow) and the refrigerant blown from the nozzle 41 (driving flow) are mixed by the mixing unit 43 and the dynamic pressure thereof is converted into static pressure by the diffuser 44. Return to the liquid separator 50.

  Next, in the defrosting operation for melting the frost adhered to the evaporator, the evaporator 30 is opened via the hot gas passage 60 with the high-temperature refrigerant (hot gas) discharged from the compressor 10 by opening the defrost control valve 61. To supply. Thereby, the refrigerant is the compressor 10 → hot gas passage 60 (drain pan 31) → first check valve 62 → evaporator 30 → ejector 40 (refrigerant inflow part 42 → mixing part 43 → diffuser 44) → gas-liquid separator. 50 → The compressor 10 is circulated in the order, and the evaporator 30 is heated to melt (defrost) the frost adhering to the surface of the evaporator 30, and at the drain pan 31, the melted water and condensed water accumulated by freezing. Heat and melt water.

  In the present embodiment, during the defrosting operation, the evaporator is defrosted and the frost attached to the ejector is melted. The ejector 40 shown in FIG. 2 is configured to control the opening degree of the nozzle 41 by the electric actuator 46 such as a stepping motor or a linear solenoid as described above. However, in the prior art, energization to the actuator 46 is stopped during hot gas defrosting. Moreover, since there is no inflow of the refrigerant from the radiator 20, the hot gas that has defrosted the evaporator 30 cannot be sucked effectively, so that the frost attached during normal operation cannot be effectively melted.

  Therefore, in this embodiment, the electric actuator is energized to cause the stepping motor to generate heat, and the ejector is defrosted by the generated heat.

  As a specific example, when a control for defrosting hot gas every certain time after the start of the refrigerator is incorporated, a control signal (such as a control signal to the refrigerant flow switching solenoid valve) at the start of defrosting is detected. The ejector nozzle is fully closed by the stepping motor. After the fully closed state, the coil of the stepping motor is excited with a constant voltage, and the coil is heated while the needle position is fixed. This heat generation melts the frost attached to the ejector. The ejector is also in the initial state of the refrigeration operation based on a control signal for completion of hot gas defrosting (for example, a control signal for detecting that the temperature of the defrosting deactivation sensor has exceeded a predetermined value and entering the solenoid valve for refrigerant flow switching) Return to.

  According to the first embodiment in which the ejector is arranged in the frosting environment as described above, the frost attached to the ejector is removed from the electric drive unit (actuator) of the ejector during the defrosting operation of the evaporator. Can melt simultaneously. Therefore, the refrigeration capacity can be greatly improved as compared with the refrigeration cycle apparatus in which the ejector is arranged in a room temperature environment.

(Second Embodiment)
FIG. 3 is an overall configuration diagram of a refrigerator for a refrigerator according to the second embodiment of the present invention, and FIG. 4 is a schematic diagram of the refrigeration cycle apparatus 3. In this embodiment, the refrigerator is applied to a truck-type refrigerator. 3 and 4, those having the same functions as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 3, the truck bed is provided with a freezer compartment (freezer) R, and the freezer compartment R is loaded with frozen food such as frozen food. Behind the freezer compartment R, a loading / unloading door D for loading frozen goods into the freezer compartment R or carrying out the frozen goods in the freezer compartment R is provided. The refrigeration vehicle is equipped with a refrigeration cycle apparatus 2 as shown in FIG. 4 as a package type refrigerator in the front part of the cargo compartment.

  The refrigeration cycle apparatus 2 includes a compressor 10, a radiator 20, a refrigerant radiated by the radiator 20 into a vapor phase refrigerant and a liquid phase refrigerant, a receiver 52 that stores the liquid phase refrigerant, and the liquid An expansion valve (decompression unit) 70 for depressurizing the phase refrigerant, a refrigerating evaporator (hereinafter simply referred to as an evaporator) 30 for evaporating the depressurized refrigerant, and the evaporator 30 and the compressor 10 are installed. It is a well-known thing which consists of the accumulator 53 which stores a liquid phase refrigerant | coolant among the refrigerant | coolants which passed the evaporator 30, and refrigerant | coolant piping which connects these.

  The cooling unit formed by the radiator 20 and the evaporator 30 is disposed on the vehicle front side outside the freezer compartment R. The cooling unit is attached to the outer wall heat insulation panel 81 of the freezer R with a hole, and is roughly divided into a portion with a built-in evaporator 30 (corresponding to a frosting environment) surrounded by a heat insulation panel 82, and a resin cover 83. And a built-in portion of the radiator 20.

  The radiator 20 is installed upright on the vehicle front side of the cooling unit so as to be easily received by the traveling wind of the vehicle, and the internal refrigerant is condensed by the traveling wind and the cooling air blown by the cooling fan 22. The

  The expansion valve 70 is an electrically controlled expansion valve, as will be described later, and includes a constant flow rate mechanism that keeps the flow rate of the refrigerant electrically constant.

  The evaporator 30 cools the freezer compartment R by the latent heat of vaporization of the refrigerant, and is disposed horizontally or obliquely in the cooling unit. Above the evaporator 30, a refrigeration fan (suction blower) 32 that sucks air from the evaporator 30 and blows it into the freezer compartment R is provided.

  In the refrigeration cycle apparatus 2 according to the present embodiment, a hot gas bypass passage (an iron, a hot gas passage) that communicates the discharge side of the compressor 10 with the downstream side of the expansion valve 70 and the upstream side of the evaporator 30. 60) is provided. The hot gas passage 60 is provided with an electromagnetic valve 61 as an opening / closing means. When the electromagnetic valve 61 is opened and hot gas is supplied to the evaporator 30, a reverse flow to the radiator 20 side is generated. A preventive on-off valve 62 is provided between the expansion valve 70 and the receiver 52.

  The hot gas passage 60 also serves as a drain pan heater tube 31 that heats the drain pan during hot gas defrosting, and is installed so as to fold the inner surface of the drain pan.

  FIG. 5 is a schematic cross-sectional view of an electrically controlled expansion valve having a suitable electric drive unit arranged in the present embodiment.

  In the expansion valve 70, a high-pressure refrigerant inlet channel 701 through which high-pressure refrigerant is sent and an expansion refrigerant outlet channel 702 through which the refrigerant is expanded and sent to the evaporator 30 are connected to the main body block 703.

  A constant flow mechanism 710 for maintaining a constant flow rate of the refrigerant is incorporated in the main body block 703, and an outlet side end portion of the refrigerant passage 711 formed in the constant flow mechanism 710 serves as a valve seat 712. Yes.

  A flow path cross-sectional area control valve body (hereinafter simply referred to as a valve body) 713 formed in a tapered shape is disposed opposite to the valve seat 712 from the downstream side, and the valve seat 712, the valve body 713, The gap between the two becomes a throttle portion of the refrigerant flow path, and the refrigerant passing therethrough is sent out from the expanded refrigerant outlet flow path 702 to the evaporator 30 while adiabatically expanding. And the flow-path cross-sectional area of the clearance gap between the valve seats 712 changes by the valve body 713 moving to an axial direction.

  In addition, a constant differential pressure valve body 715 that is inserted in a cylinder hole 714 formed in parallel with the refrigerant passage 711 so as to be movable in the axial direction is urged from the downstream side by a compression coil spring 716, and the constant differential pressure valve The other end (upstream end portion) of the body 715 is a valve portion that opens and closes between the high-pressure refrigerant inlet channel 701 and the refrigerant passage 711 that open from the side.

  As a result, the pressure difference (P0−P2) between the refrigerant pressure P0 in the refrigerant passage 711 and the refrigerant pressure P2 on the expansion refrigerant outlet channel 702 side is set to the magnitude of the high-pressure refrigerant pressure P1 on the high-pressure refrigerant inlet channel 701 side. Regardless, the constant differential pressure valve body 715 operates so as to maintain the constant value set by the compression coil spring 716.

  The valve body 713 is formed integrally with the movable iron core 733 of the solenoid 730. 731 is an electromagnetic coil, and 732 is a fixed iron core. Therefore, the valve body 713 is thrust applied to the movable iron core 733 in accordance with the urging force of the compression coil spring 734 disposed between the movable iron core 733 and the fixed iron core 732 and the energization current value to the electromagnetic coil 731. The cross-sectional area of the refrigerant passage formed by the gap between the valve seat 712 and the valve body 713 is controlled by the value of the energization current to the electromagnetic coil 731.

  In the electric control expansion valve 70 configured in this way, the differential pressure across the refrigerant passage (P0-P2) formed by the gap between the valve seat 712 and the valve body 713 is constant, so that the electromagnetic coil 731 The constant flow mechanism 710 keeps the flow rate of the refrigerant constant if the flow current cross-sectional area is kept constant while keeping the energization current value constant.

  Then, when the energizing current value to the electromagnetic coil 731 is changed to change the thrust of the movable iron core 733, the refrigerant passage formed by the gap between the valve seat 712 and the valve body 713 is correspondingly changed. The cross-sectional area changes without changing the front-back differential pressure, and the flow rate of the refrigerant changes by a predetermined magnitude. Therefore, the flow rate of the refrigerant can be electrically accurately controlled without being affected by the pressure P1 of the high-pressure refrigerant sent to the high-pressure refrigerant inlet channel 701.

  The electric control expansion valve according to the present invention is not limited to the above-described embodiment. For example, the means for performing the electric control is not limited to the solenoid, but may be various types such as a step motor, a DC motor, or an AC motor. Can be used.

  In FIG. 4, a control device 90 is configured to include computer means such as a microcomputer, and performs arithmetic processing based on a signal from an input terminal to control the refrigeration cycle. Connected to the control device 90 are a temperature setter 34 for setting a set temperature in the freezer compartment R as an input signal and a freezing start switch 36 for starting freezing in the freezer compartment R.

  The temperature setter 34 is configured by, for example, a variable resistor, and the set temperature can be arbitrarily changed in a range from −10 ° C. to −20 ° C., for example. On the other hand, the control device 90 includes, as output signals, an energization circuit (not shown) of the electromagnetic clutch 14 of the compressor 10, an expansion valve 70, an electromagnetic valve 61, a cooling fan 22, an on-off valve 62, and a freezing fan. 32 is connected.

  The control device 90 is supplied with electric power when an ignition switch (not shown) of the vehicle is turned on. When the refrigeration start switch 36 is turned on (a signal for cooling the freezer compartment R is generated) in a state where the ignition switch is turned on, the temperature in the freezer compartment R is changed by the control device 90 to the above temperature. It is automatically controlled so as to be a set temperature (for example, -20 ° C.) set by the setter 34.

  Specifically, when the refrigeration start switch 36 is turned on, the control device 90 energizes the electromagnetic clutch 14 to connect the vehicle traveling engine and the compressor 10 to drive the compressor 10 ( ON). Further, at this time, the control device 90 starts cooling the freezer compartment R by operating (ON) the cooling fan 22, the freezing fan 32, and the expansion valve 70.

  Thereafter, when the freezer temperature detected by a freezer temperature sensor (not shown) reaches the set temperature (−20 ° C.), the electromagnetic clutch 14 is deenergized, and the vehicle running engine and the compressor 10 are connected. Is shut off (OFF), and the cooling fan 22 and the refrigeration fan 32 are stopped (OFF). At this time, the expansion valve 70 is maintained in a state that is not fully closed before the compressor 10 stops, and the electric control unit is not energized.

  For example, when the temperature in the freezer compartment 2 is slightly higher than the set temperature and becomes −18 ° C., the compressor 10 is driven as described above, and the cooling fan 22 and the freezing fan 32 are operated. The solenoid valve 61 is in a closed state (OFF) and the on-off valve 62 is in an open state (ON) except when hot gas defrosting described later is performed.

  By the way, as mentioned above, in the freezer car, since the temperature in the freezer compartment becomes an extremely low temperature of −20 ° C., frost adheres to the evaporator 30, thereby reducing the cooling capacity of the evaporator 30. Moreover, when frost adheres also to the expansion valve 70 arrange | positioned in the freezer compartment R and it was not able to remove completely by the defrosting operation of the evaporator 30, it further forms frost at the time of freezing operation, and the evaporator 30 There is a possibility that the refrigeration capacity is lowered by closing the ventilation path, and an object (for example, a wall or a duct) around the expansion valve is damaged. Therefore, in the present embodiment, defrosting control for removing frost attached to the evaporator 30 and the expansion valve 70 is performed. In the present embodiment, the controller 90 performs the following hot gas defrosting operation on the evaporator 30 as the defrost control, and at the same time, the expansion valve 70 generates the coil portion to the electromagnetic coil 731. Defrosting energization (excitation) is performed.

  When the refrigeration start switch 36 is turned on while the ignition switch is turned on, the refrigeration operation is started and a timer in the control device 90 is started. When a predetermined time (for example, 3 hours) elapses, hot gas The defrosting operation is started.

  Specifically, with the electromagnetic clutch 14 kept on, the electromagnetic valve 61 is opened (ON), and high-temperature and high-pressure gas-phase refrigerant (hot gas) is directly evaporated through the hot gas passage 60 by the compressor 10. Pour into vessel 30. At this time, the on-off valve 62 is closed (OFF) so that hot gas does not flow back to the condenser 20 side. Then, the freezing fan 32 and the cooling fan 22 are stopped. Thereby, the frost adhering to the evaporator 30 is melt | dissolved with the heat | fever of hot gas, and a defrost is performed effectively.

  Subsequently, it is determined whether or not to end the hot gas defrosting. Specifically, hot gas defrosting ends when the temperature detected by a defrosting release sensor (not shown) is higher than a predetermined temperature (for example, 3 ° C.). In addition, when hot gas defrosting is performed, naturally frost melts sequentially from the refrigerant | coolant upstream side of the evaporator 30. FIG. Therefore, in this embodiment, since the defrost release sensor is installed on the downstream side of the evaporator 30, the hot gas defrosting is finished when the frost attached to the entire evaporator 30 is completely melted. it can. That is, when the detection temperature of the defrost release sensor (pipe temperature immediately downstream of the evaporator 30) is higher than 3 ° C., it is determined that the frost attached to the evaporator 30 has been sufficiently removed.

  When the condition for ending the hot gas defrosting is reached, the electromagnetic clutch 14 is once turned off, the electromagnetic valve 61 is closed (OFF), and the on-off valve 62 is returned to the open state (ON). Next, with the refrigeration fan 32 stopped, the electromagnetic clutch 14 and the cooling fan 22 are turned on to start the refrigeration cycle, and a precooling operation is performed. When the evaporator 30 is in a state where it can emit cold air of a predetermined temperature or less, the refrigeration fan 32 is turned on to restart the refrigeration operation. At this time, the timer for measuring a predetermined time until the next defrosting operation is reset and restarted.

  In the present embodiment, defrosting of frost adhering to the electrically controlled expansion valve 70 is performed in parallel with the hot gas defrosting as described above. Conventionally, since the expansion valve 70 has not been arranged in a frosting environment, the expansion valve 70 is in an off state during the defrosting operation in which hot gas is passed through the evaporator 30.

  However, in the present embodiment, the electric control unit (electromagnetic coil 731) of the expansion valve is energized with a pulse or a predetermined constant voltage to cause the electromagnetic coil 731 to generate heat, and the entire expansion valve 70 generates heat. For this reason, the attached frost can be melted to defrost the expansion valve. Subsequently, it is determined whether or not the energization defrosting is finished. Specifically, the hot gas defrosting completion control signal (for example, a control signal that detects that the temperature of the defrost release sensor has become equal to or higher than a predetermined temperature and enters the refrigerant flow switching electromagnetic valve) is removed. The frost is over.

  According to the present embodiment in which the electrically controlled expansion valve is arranged in the frosting environment as described above, by energizing the electromagnetic coil of the expansion valve, frost adhering to the expansion valve is simultaneously removed during the defrosting operation of the evaporator. Can melt. Therefore, it is possible to solve the problem of improving the refrigeration capacity by disposing the expansion valve in a frost environment and preventing frost formation on the expansion valve.

  In addition, the refrigerating cycle apparatus of this invention is not limited to said embodiment, It can change in the range which does not deviate from the meaning of this invention.

  For example, in the above-described first and second embodiments, the evaporator defrosting method is applied to a refrigeration cycle apparatus in which hot gas defrosting is performed. However, heater defrosting and refrigeration cycle operation for heating the evaporator with heater are performed. The present invention can also be applied to a refrigeration cycle apparatus such as an off-cycle defrost that stops and defrosts only by flowing wind through the evaporator. In the present invention, the depressurizing means disposed in the refrigeration cycle has been described. However, any functional product that is disposed in the refrigeration cycle and that is driven by electric energy used in a frosting environment can be removed. Frost energization can be applied. Furthermore, in addition to the purpose of defrosting in a frosting environment, it may be used for the purpose of preventing condensation in a condensation environment.

  The refrigeration cycle apparatus of the present invention can be applied to a refrigeration cycle apparatus using any refrigerant such as chlorofluorocarbon or carbon dioxide gas.

  The refrigeration cycle apparatus of the present invention can be suitably used as a refrigeration cycle apparatus such as a refrigeration cycle apparatus as a vehicle air conditioner or an in-vehicle refrigerator of a truck refrigeration vehicle.

It is the figure which showed typically the ejector cycle concerning 1st Embodiment. It is a schematic diagram which shows the cross section of the ejector of 1st Embodiment. It is a whole block diagram of the freezer for refrigerators concerning 2nd Embodiment. It is a schematic diagram of the refrigerating cycle concerning 2nd Embodiment. It is a schematic diagram which shows the cross section of the electrically controlled expansion valve of 2nd Embodiment.

Explanation of symbols

1: Ejector cycle 2: Expansion valve refrigeration cycle 10: Compressor 20: Radiator 30: Evaporator 40: Ejector 50: Gas-liquid separator 60: Hot gas bypass flow path 70: Electrically controlled expansion valve 90: Control means 41: Nozzle 42: Refrigerant inflow part 43: Mixing part 44: Diffuser 45: Needle 46: Electric drive part (accumulator) 712: Valve seat 713: Valve body 730: Electromagnetic coil

Claims (6)

At least a compressor that compresses and discharges the refrigerant at high temperature and high pressure, a radiator that dissipates the refrigerant compressed by the compressor, and an electric drive unit that uses electric energy as driving energy, and is radiated by the radiator In a refrigeration cycle apparatus comprising: a decompression unit that decompresses the refrigerant; an evaporator that evaporates the refrigerant decompressed by the decompression unit; and a defrosting unit that defrosts frost attached to the evaporator.
A refrigeration cycle apparatus, wherein the decompression unit is disposed in a frosting environment, and the electric drive unit is energized to melt frost attached to the decompression unit.   The defrosting means bypasses the refrigerant discharged from the compressor and bypasses the decompression means and leads to the evaporator, and an inflow prevention that prevents the refrigerant from flowing into the hot gas path during normal operation. The refrigeration cycle apparatus according to claim 1, further comprising: means.   The decompression means converts the pressure energy of the high-pressure refrigerant flowing out from the radiator into velocity energy, decompresses and expands the refrigerant, an electric drive unit that variably controls the throttle opening of the nozzle, and injects from the nozzle The vapor pressure refrigerant evaporated in the evaporator is sucked by a high-speed refrigerant flow, and the velocity energy is converted into pressure energy while mixing the refrigerant injected from the nozzle and the refrigerant sucked from the evaporator, thereby converting the pressure of the refrigerant. The refrigeration cycle apparatus according to claim 1, wherein the refrigeration cycle apparatus is an ejector having a diffuser for boosting the pressure.   The refrigeration cycle apparatus according to claim 1 or 2, wherein the decompression means is an electrically controlled expansion valve that electrically controls the flow rate of the refrigerant by an electric drive unit.   The refrigeration cycle apparatus according to claim 3 or 4, wherein the electric drive unit includes any of a stepping motor, a DC motor, or an AC motor.   The refrigeration cycle apparatus according to claim 5, wherein energization control is performed on the electric drive unit of the depressurizing means that has frosted with a pulse wave, a rectangular wave, a DC voltage, or an AC voltage.

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