KR100560561B1 - Continuously operating type showcase - Google Patents

Abstract

The present invention relates to a continuous operation type showcase capable of performing defrosting operation in parallel while continuously executing the cooling operation without stopping the cooling operation for defrosting. The cold air duct surrounding the reservoir is combined with the inlet duct section through which air is introduced from the reservoir, the first and second branch duct sections branching from the inlet duct section, and the tip portions of the first and second branch duct sections are combined. It has a discharge side duct part which discharges air. The first and second heat exchangers are respectively installed in series in the first and second branch ducts, and expansion valves are installed in the pipes connecting the first and second heat exchangers. The discharge pipe of the condenser is provided with a direction switching valve for selectively flowing the refrigerant flowing out of the condenser to the heat exchanger of either one of the first heat exchanger and the second heat exchanger. A blower is installed in the inlet side duct part, and first and second dampers are respectively installed in the connection portion of the inlet side duct part and the first and second branch duct parts. The control unit controls the operation of the directional valve and the first and second dampers in response to the refrigerant saturation temperature signals of the first and second heat exchangers and the cold air temperature signals after heat exchange with the sensors.

Showcase, Defrost, First Heat Exchanger, Second Heat Exchanger, Directional Valve

Description

Continuous Driving Showcase {CONTINUOUSLY OPERATING TYPE SHOWCASE}

1 is a cross-sectional view showing the internal structure of a conventional showcase,

2 is a schematic view showing a conventional refrigeration cycle of a showcase,

3 is a cross-sectional view showing the internal structure of the continuous operation showcase according to the first embodiment of the present invention;

4 is a configuration diagram showing an example of the operation of the refrigeration cycle of the continuous operation showcase according to the first embodiment of the present invention,

5 is a configuration diagram showing another operation example of the refrigeration cycle of the continuous operation showcase according to the first embodiment of the present invention,

6 is a configuration diagram showing an example of the operation of the refrigeration cycle of the continuous operation showcase according to the second embodiment of the present invention,

7 is a configuration diagram showing another example of operation of the refrigeration cycle of the continuous operation showcase according to the second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: showcase 110: main body

112: blower 114: first heat exchanger

115: second heat exchanger 116: expansion valve

120: storage 122: shelves

124: cold air outlet 126: cold air inlet

130: cold air duct 132: inlet side duct

134: first branch duct portion 135: second branch duct portion

136: discharge side duct portion 138: first damper

139: second damper 140: enclosure

142: accumulator 144: compressor

146: condenser 148: directional control valve

149: refrigerant amount control valve 150, 152, 154, 156: piping

The present invention relates to a showcase, and more particularly, having two heat exchangers and when one side heat exchanger performs a function of an evaporator to perform a refrigeration or freezing operation, at the same time the other side heat exchanger functions as a secondary condenser. The present invention relates to a continuously operated showcase for performing defrost by performing heat of condensation of a refrigerant.

In general, the showcase is a device for freshly storing various frozen foods such as ice cream, food and beverage, meat or vegetables, fruits and vegetables at a temperature suitable for food-specific characteristics, and the inside temperature, humidity, and illuminance must be properly maintained. . According to the development of the distribution industry, showcases of various temperature ranges are currently used, which are largely classified into refrigeration of about 4 ° C and refrigeration of about -20 ° C.

An example of such a showcase is disclosed in Japanese Patent Laid-Open No. 1999-094442, which will be described with reference to FIGS. 1 and 2. 1 is a cross-sectional view showing the internal structure of a conventional showcase, Figure 2 is a schematic view showing a refrigeration cycle of a conventional showcase.

As shown in the drawing, the conventional showcase 1 includes a main body 10 forming an exterior, a storage 20 for opening a front surface of the product, and a cold air duct surrounding the storage 20. 30 and a housing 40 positioned below the reservoir 20 to accommodate the compressor 44, the condenser 46, and the like.

The inside of the reservoir 20 is provided with a plurality of shelves 22 to enable the display of goods, the upper one side of the cold air discharge port 24 is discharged air curtain (arrow in Fig. 1) in front of the reservoir 20 Is formed, the cold air inlet 26 is formed on the lower side to correspond to the cold air discharge port (24).

The cold air duct 30 surrounding the reservoir 20 is provided on the lower side of the reservoir 20 and vertically extended along the rear of the inlet side duct part 32 and the reservoir 20 communicated with the cold air inlet 26. The duct part 34 and the discharge side duct part 36 which is provided on the upper side of the reservoir 20 and communicates with the cold air discharge port 24 is comprised.

Inside the inlet side duct part 32, a blower 12 is installed to suck air around the reservoir 20 and send it to the vertical duct part 34 side. Inside the vertical duct 34, the upstream evaporator 14 and the downstream evaporator 15 are arranged in order from the bottom.

A receiver 40, a compressor 44, a condenser 46, and the like are installed inside the enclosure 40 located below the reservoir 20. The first expansion valve 16 is installed in the pipe 52 connecting the condenser 46 and the upstream evaporator 14, and the pipe 54 connecting the condenser 46 and the downstream evaporator 15 is provided. Two expansion valves 17 are provided. In the middle of the pipe 50 connecting the compressor 44 and the condenser 46, bypass pipes 56 and 58 for direct connection between the compressor 44 and the upstream and downstream evaporators 14 and 15 are branched. Each of the bypass pipes 56 and 58 is provided with first and second defrost expansion valves 18 and 19.

Hereinafter, the operation of the conventional showcase configured as described above will be described.

When the refrigeration or freezing operation is started, the gas refrigerant in the receiver 42 is sucked into the compressor 44, as indicated by the solid arrow in FIG. The gas refrigerant is compressed to a high temperature and a high pressure in the compressor 44 and then flows into the condenser 46 through the pipe 50 to condense and liquefy.

A part of this liquid refrigerant flows into the first expansion valve 16 opened via the pipe 52 to be depressurized, and then flows into the upstream evaporator 14. In addition, the remaining liquid refrigerant flows into the second expansion valve 17 via the pipe 54 to be depressurized and then flows into the downstream evaporator 15. At this time, the first and second defrost expansion valves 18 and 19 remain closed. The liquid refrigerant introduced into the upstream and downstream evaporators 14 and 15 is evaporated and vaporized in the evaporators 14 and 15 and then returned to the receiver 42 and stored. In this way, the gas refrigerant stored in the receiver 42 is again sucked into the compressor 44, and the above-mentioned refrigeration or freezing operation cycle is repeated.

The upstream and downstream evaporators 14 and 15 have their surface temperatures below the freezing point due to the latent heat of vaporization accompanying the vaporization of the liquid refrigerant, thereby cooling the air passing between the cooling fins. The cooled air circulates in the reservoir 20 by the blower 12 in the form of an air curtain indicated by an arrow in FIG. 1, and cools or freezes the goods on the display rack 22 to a predetermined temperature.

As the refrigeration or freezing operation continues, moisture in the air condenses on the surfaces of the evaporators 14 and 15, causing frost to form. The implantation reduces the effective passage area of the air and thus reduces the airflow, so that the cooling effect of the showcase is reduced or even the function is lost. Therefore, defrosting should be done periodically. To this end, by closing the first and second expansion valves 16 and 17 and opening the first and second defrost expansion valves 18 and 19, the compressor 44 as indicated by the dotted arrows in FIG. Hot gas discharged from the air is directly sent to the evaporators 14 and 15 to remove frost.

In addition to the defrosting method using the hot gas as described above, the compressor operation is stopped and the air circulation fan in the main body is operated to defrost by the surrounding air (off cycle defrosting method), and an electric heater is installed near the evaporator to generate the heater. There is a method of defrosting by the heat generated (electric heater defrosting method).

However, in the conventional defrosting method as described above, since the freezing or cooling operation must be stopped during the defrosting operation, the internal temperature of the food inevitably rises during the defrosting operation time, which is good for maintaining the freshness of the food stored in the refrigerator. Has the problem of not affecting. In particular, the off-cycle defrosting method has a relatively long defrosting time, and the electric heater defrosting method consumes a lot of power for the operation of the heater, and pays special attention to electrical insulation. Because of the circulation, the internal temperature can be raised to 20 ℃, causing a fatal damage to the freshness of food. In addition, there is a problem in that the operating cost of the showcase is high due to a large amount of power consumption for returning the high temperature inside the elevated temperature up to 20 ° C to a low temperature steady state.

In addition, if defrosting is severe and the defrosting is not performed by the conventional defrosting method, the refrigeration cycle must be completely stopped and the main body must be dismantled to sprinkle the frosted evaporator around with hot water to remove frost artificially. In this case, the maintenance of the product is damaged due to the interruption of the cooling and also requires a lot of maintenance costs.

The present invention is to solve the problems of the prior art, an object of the present invention is to provide a continuous operation type showcase that can perform the defrost operation in parallel while executing the continuous cooling operation without stopping the cooling operation for defrosting will be.

Another object of the present invention is to provide a continuous operation type showcase that can significantly reduce the operating cost by eliminating the additional power consumption according to the defrosting operation and cooling operation restart as in the prior art.

Continuous operation showcase according to the present invention for achieving the above object is a compressor for compressing the refrigerant, a condenser for condensing the refrigerant discharged from the compressor, a cold air duct for circulating the cold air into the reservoir, and a refrigerant in the cold air duct The first and second heat exchangers, which are installed to be connected to each other so as to pass sequentially, the expansion valve installed between the first heat exchanger and the second heat exchanger, and the refrigerant flowing out of the condenser. Redirect valve for selectively flowing to the heat exchanger on one side, air flow means for selectively flowing the air in the reservoir to any one of the first heat exchanger and the second heat exchanger, and the refrigerant passed through the first and second heat exchangers To measure the outlet temperature, the refrigerant saturation temperature, and the cold air temperature after heat exchange by the first and second heat exchangers Characterized in that in response to a temperature signal detected by the sensor, the sensor comprising a control section for controlling the directional control valve and operation of the air flow means.

The cold air duct joins the inlet side duct section into which air is introduced from the reservoir, the first and second branch duct sections extending from the inlet side duct section, and the tip portions of the first and second branch duct sections to discharge air into the reservoir. Having a discharge side duct part, the first and second heat exchangers are respectively installed in the first and second branch duct parts and connected in series with each other.

The air flow means includes a blower installed in the inlet side duct section of the cold air duct, a first damper installed in the connection section of the inlet side duct section and the first branch duct section, and a connection section of the inlet side duct section and the second branch duct section. And a second damper installed.

The controller determines whether the difference between the temperature of the cold air heat exchanged by the first heat exchanger from the sensor and the refrigerant saturation temperature of the first heat exchanger is greater than or equal to the preset value, and if less than the preset value, the refrigerant flowing out of the condenser is transferred to the second heat exchanger. Control the directional valve to flow, execute the first operation mode in which the first damper is open and the second damper is closed, and if it is above the preset value, the refrigerant flowing out of the condenser flows to the first heat exchanger. And to switch the valve, to close the first damper and to open the second damper.

In addition, when the second operation mode is being executed, the controller determines whether the difference between the temperature of the cold air heat exchanged by the second heat exchanger and the refrigerant saturation temperature of the second heat exchanger from the sensor is greater than or equal to the preset value. It is configured to maintain the second operation mode and to switch to the first operation mode if it is equal to or more than the preset value.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

3 is a cross-sectional view showing the internal structure of the continuous operation showcase according to the first embodiment of the present invention, Figures 4 and 5 shows an operation example of the refrigeration cycle of the continuous operation showcase according to the first embodiment of the present invention. The configuration diagram shown.

As shown, the continuous driving showcase 100 according to the present invention is a main body 110 to form an appearance, the front opening is open and the storage 120 for displaying goods therein, and the storage 120 The surrounding cold air duct 130 and a housing 140 positioned below the reservoir 120 to accommodate the compressor 144, the condenser 146, and the like.

The inside of the reservoir 120 is provided with a plurality of shelves 122 to enable the display of goods, the cold air discharge port 124 is discharged to the air curtain (arrow of Figure 3) in front of the reservoir 120 on the upper one side Is formed, the cold air inlet 126 is formed on the lower side to correspond to the cold air outlet 124.

The cold air duct 130 surrounding the reservoir 120 is provided at the lower side of the reservoir 120 and branched from the inlet side duct part 132 and the inlet side duct part 132 communicating with the cold air inlet 126. The first and second branch duct portions 134 and 135 vertically extending along the rear of the 120 and the ends of the first and second branch duct portions 134 and 135 are merged into one and the upper side of the reservoir 120. It is provided in the discharge side duct portion 136 is in communication with the cold air discharge port (124). The inlet side duct part 132 and the connection part of the 1st and 2nd branch duct part 134 and 135 mutually communicate between the inlet side duct part 132 and the 1st and 2nd branch duct part 134,135. First and second dampers 138 and 139 are provided respectively for blocking or blocking.

Inside the inlet-side duct part 132, a blower 112 is installed to suck air around the reservoir 120 and send it to the first or second branch duct parts 134 and 135. The first heat exchanger 114 is installed inside the first branch duct unit 134, and the second heat exchanger 115 is installed inside the second branch duct unit 135. The refrigerant pipes of the first heat exchanger 114 and the second heat exchanger 115 are connected in series with each other, and the pipe 150 connecting the first heat exchanger 114 and the second heat exchanger 115 expands. The valve 116 is installed.

The accumulator 142 and the compressor 144 and the compressor 144 discharged from the compressor 144 to suck and compress the gas refrigerant in the accumulator 142 to a high temperature and high pressure inside the housing 140 located below the reservoir 120. The liquid refrigerant discharged from the condenser 146 and installed in the condenser 146 and the discharge end side pipe 154 of the condenser 146 for condensing and liquefying a high-temperature, high-pressure gas refrigerant is discharged from the first heat exchanger 114 or the first heat exchanger. A diverter valve 148 for selectively supplying to either side of the two heat exchangers 115, and branched from the pipe 152 connecting the compressor 144 and the condenser 146, and the discharge end side pipe of the condenser 146. The refrigerant amount control valve 149 installed in the bypass pipe 156 and the bypass pipe 156 connected to the 154 and discharged from the compressor 144 to flow into the condenser 146 is provided. Is installed.

Further, a sensor for measuring the outlet temperature of the refrigerant passing through the first and second heat exchangers 114 and 115, the refrigerant saturation temperature, and the cold air temperature after heat exchange with the first and second heat exchangers 114 and 115 ( And a temperature signal detected from the sensor, and controlling the operation of the direction change valve 148, the first and second dampers 138 and 139, and the refrigerant amount control valve 149 in response to the signal. A control unit (not shown) is provided.

Hereinafter, the operation of the continuous operation showcase according to the present invention configured as described above will be described.

When the refrigeration or freezing operation is started, the gas refrigerant in the accumulator 142 is sucked into the compressor 144, as indicated by the arrow of FIG. After the gas refrigerant is compressed at a high temperature and high pressure in the compressor 144, some gas refrigerant flows into the condenser 146 through the pipe 152 to condense and liquefy, and the remaining gas refrigerant passes through the bypass pipe 156. Through the refrigerant amount control valve 149 flows along the discharge end side pipe 154 of the condenser 146. As a result, the gas refrigerant discharged from the compressor 144 and the liquid refrigerant discharged from the condenser 146 are mixed in the discharge end side pipe 154 of the condenser 146, which passes through the directional valve 148. It is introduced into the two heat exchanger (115). Accordingly, the second heat exchanger 115 serves as an auxiliary condenser so that the gas refrigerant is condensed and liquefied, and defrosting is performed in the second heat exchanger 115 by the heat of condensation.

The refrigerant amount control valve 149 is for controlling the defrost capacity of the second heat exchanger 115 that acts as an auxiliary condenser. In detail, as the opening degree of the control valve 149 increases, the amount of refrigerant discharged from the compressor 144 and passing through the condenser 146 decreases, so that the amount of condensation in the condenser 146 decreases. While the amount of condensation in the 115 increases, the defrosting capacity increases relatively, while the smaller the opening degree of the control valve 149, the greater the amount of refrigerant passing through the condenser 146, but condensation in the second heat exchanger 115. As the amount decreases, the defrost capacity is relatively reduced. The degree of opening of the refrigerant amount control valve 149 is controlled by a controller that receives a refrigerant outlet temperature signal detected from a sensor installed at a refrigerant outlet of the second heat exchanger 115. The opening degree of the refrigerant amount control valve 149 is adjusted in accordance with the difference from the reference temperature. That is, when the detected refrigerant outlet temperature (eg 35 ° C.) is lower than the reference temperature (eg 38 ° C.), this means that the second heat exchanger 115 is in an implanted state, and thus the refrigerant amount control valve 149 is used. By increasing the opening degree of the defrosting capacity of the second heat exchanger 115 is increased.

The liquid refrigerant that is completely condensed and liquefied while passing through the second heat exchanger 115 flows along the pipe 150 connecting the first heat exchanger 114 and the second heat exchanger 115 and is installed in the pipe 150. Pressure is reduced by the expansion valve 116, and then flows into the first heat exchanger (114). At this time, the first heat exchanger 114 performs the function of an evaporator, and the liquid refrigerant introduced into the first heat exchanger 114 is evaporated and vaporized in the first heat exchanger 114. The first heat exchanger 114 has a surface temperature below the freezing point due to the latent heat of vaporization accompanying the vaporization of the liquid refrigerant, and cools the air passing between the cooling fins. At this time, the controller opens the first damper 138 located between the inlet duct 132 and the first branch duct 134 of the cold air duct 130, and the inlet duct 132 and the second. The second damper 139 located between the branch ducts 135 maintains the closed state. Therefore, the air around the reservoir 120 is introduced into the inlet duct part 132 through the cold air inlet 126 by the operation of the blower 112, and the first branch duct through the open first damper 138. Cooling through the first heat exchanger 114 installed in the section 134. The cold air circulates through the cold air discharge port 124 in the form of an air curtain indicated by an arrow in FIG. 3 via the discharge-side duct part 136, and cools or freezes the goods on the display rack 122 to a predetermined temperature.

Thereafter, the gas refrigerant discharged from the first heat exchanger 114 is returned to the accumulator 142 through the direction switching valve 148 and stored. As such, the gas refrigerant stored in the accumulator 142 is sucked back into the compressor 144 and then the above-mentioned refrigeration or freezing operation cycle is repeated.

As the refrigeration or freezing operation continues, moisture in the air condenses on the surface of the first heat exchanger 114, causing frost to form. When the concept of the first heat exchanger 114 is deepened, as shown in FIG. 5, the control unit operates the direction switching valve 148 to switch the flow of the refrigerant. The temperature signal of the exchanged cold air and the refrigerant saturation temperature signal of the first heat exchanger 114 are input from the sensor, and the temperature of the cold air (for example, −25 ° C.) and the refrigerant saturation temperature of the first heat exchanger 114 (eg For example, the control unit operates the direction change valve 148 at a time when the difference of -45 ° C) becomes equal to or more than the preset reference value. This acts to hinder the heat exchange with the air in the first heat exchanger 114 in the castle formed on the surface of the first heat exchanger 114, so that the temperature of the cold air and the first heat exchanger 114 as the conception proceeds. This is because the difference between the refrigerant saturation temperature of the.

As indicated by the arrows in FIG. 5, the gas refrigerant in the accumulator 142 is sucked into the compressor 144, and after being compressed to high temperature and high pressure in the compressor 144, some gas refrigerant is condensed through the pipe 152. 146 flows into the condensation and liquefaction, and the remaining gas refrigerant flows into the discharge end side pipe 154 of the condenser 146 through the bypass pipe 156 through the refrigerant amount control valve 149. As a result, the gas refrigerant discharged from the compressor 144 and the liquid refrigerant discharged from the condenser 146 are mixed in the discharge end side pipe 154 of the condenser 146, which passes through the directional valve 148. It is introduced into one heat exchanger (114). Accordingly, the first heat exchanger 114 serves as a secondary condenser so that the gas refrigerant is condensed and liquefied, and defrosting is performed in the first heat exchanger 114 by the heat of condensation. At this time, the controller controls the opening degree of the refrigerant amount control valve 149 according to the difference between the refrigerant outlet temperature of the first heat exchanger 114 and the preset reference temperature detected by the sensor to defrost the first heat exchanger 114. Adjust the dose.

The liquid refrigerant completely condensed and liquefied while passing through the first heat exchanger 114 flows along the pipe 150 connecting the first heat exchanger 114 and the second heat exchanger 115, and is installed in the pipe 150. After the pressure is reduced by the expansion valve 116, it is introduced into the second heat exchanger 115. At this time, the second heat exchanger 115 functions as an evaporator, and the liquid refrigerant introduced into the second heat exchanger 115 is evaporated and vaporized in the second heat exchanger 115. The second heat exchanger 115 has a surface temperature below the freezing point due to the latent heat of vaporization accompanying the vaporization of the liquid refrigerant, and cools the air passing between the cooling fins. At this time, the first damper 138 located between the inlet side duct unit 132 and the first branch duct unit 134 of the cold air duct 130 is switched to a closed state by the control unit, and the inlet side duct unit 132 ) And the second damper 139 positioned between the second branch duct 135 is switched to the open state. Therefore, the air around the reservoir 120 is introduced into the inlet duct part 132 through the cold air inlet 126 by the operation of the blower 112, and the second branch duct through the open second damper 139. It cools through the 2nd heat exchanger 115 installed in the part 135. The cold air passes through the discharge side duct 136 and circulates through the cold air discharge port 124 in the form of an air curtain indicated by an arrow in FIG. 3, and cools or freezes the goods on the display rack 122 to a predetermined temperature.

Thereafter, the gas refrigerant discharged from the second heat exchanger 115 returns to the accumulator 142 via the direction switching valve 148 and is stored. As such, the gas refrigerant stored in the accumulator 142 is sucked back into the compressor 144 and then the above-mentioned refrigeration or freezing operation cycle is repeated.

Similarly, when the difference between the temperature of the cold air heat exchanged by the second heat exchanger 115 and the refrigerant saturation temperature of the second heat exchanger 115 becomes equal to or more than a preset value, the controller operates the directional valve 148. In order to switch to the operation mode as shown in FIG.

6 and 7 is a configuration diagram showing an operation example of the refrigeration cycle of the continuous operation showcase according to the second embodiment of the present invention.

As shown, the refrigeration cycle of the continuous operation showcase according to the second embodiment of the present invention see the blowers 112, 4 installed in the refrigeration cycle according to the first embodiment described with reference to Figures 4 and 5 ) And the first and second dampers (138, 139), and the inlet side duct section 132 and the first and second to selectively flow the outside air into the first or second branch duct section (134, 135) The first blower 112a and the second blower 112b are respectively installed at the connection portions of the second branch ducts 134 and 135. All other components except the first and second blowers 112a and 112b are the same as the components of the refrigerating cycle according to the first embodiment, and therefore the same components are assigned the same numbers. In addition, the defrost / cool operation mode switching and the operation control method of the first and second blowers 112a and 112b according to the mode switching and the control of the first and second dampers 138 and 139 in the first embodiment. Since the method is the same, a detailed description thereof will be omitted.

As shown in FIG. 6, the second heat exchanger 115 serves as a secondary condenser and defrosts the liquid. The refrigerant is evaporated and vaporized in the first heat exchanger 114 to cool the air passing therethrough. In the operation mode, the control unit rotates only the first blower 112a positioned between the inlet-side duct part 132 and the first branch duct part 134 of the cold air duct 130 (see FIG. 3). The surrounding air passes through the inlet side duct 132 and the first branch duct 134 through the cold air inlet 126 to exchange heat with the first heat exchanger 114 to cool. The cold air circulates through the cold air discharge port 124 in the form of an air curtain indicated by an arrow in FIG. 3 via the discharge-side duct part 136, and cools or freezes the goods on the display rack 122 to a predetermined temperature. The control unit performs defrosting operation on the first heat exchanger 114 when the difference between the temperature of the cold air heat exchanged by the first heat exchanger 114 and the refrigerant saturation temperature of the first heat exchanger 114 is equal to or greater than a preset value. As determined to be necessary, the direction switching valve 148 is operated to switch to the operation mode as shown in FIG.

As shown in FIG. 7, the first heat exchanger 114 serves as an auxiliary condenser and defrost is formed. The liquid refrigerant is evaporated and vaporized in the second heat exchanger 115 to cool the air passing therethrough. When the operation mode is changed, only the second blower 112b positioned between the inlet side duct part 132 of the cold air duct 130 and the second branch duct part 135 rotates, so that the air around the reservoir 120 is cold. As it passes through the inlet duct 132 and the second branch duct 135 through the inlet 126, it is cooled by the second heat exchanger 115 and discharged into the reservoir 120. Similarly, when the difference between the temperature of the cold air heat exchanged by the second heat exchanger 115 and the refrigerant saturation temperature of the second heat exchanger 115 becomes equal to or more than a preset value, the controller operates the direction change valve 148. Switch to the operation mode as shown in FIG.

The present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims.

As described in detail above, in the continuous operation showcase according to the present invention, when using one heat exchanger as an evaporator having two heat exchangers, the other heat exchanger performs a role of an auxiliary condenser so that defrosting is performed by heat of condensation. If the heat exchanger used in the evaporator is deepened, the flow of refrigerant and air is switched so that the heat exchanger used as the evaporator serves as a subcondenser to perform defrosting, and the heat exchanger used as the subcondenser serves as an evaporator. As a result, the defrosting operation can be performed in parallel while the cooling operation is continuously executed without interruption of the cooling operation, whereby the freshness of food products and the like displayed on the showcase can be maintained in the long term.

In addition, since defrosting is performed by the heat of refrigerant condensation, there is no power consumption in the conventional defrosting electric heater, which significantly reduces the operating cost. In the case of severe conception, the main body of the showcase is dismantled so that the surroundings of the heat exchanger can be sprayed with hot water. Therefore, since the work of artificially thawing is eliminated, the maintenance cost is also greatly reduced.

Claims (10)

In a showcase having a storage for displaying goods, and maintaining the storage at a predetermined temperature, A compressor for compressing the refrigerant; A condenser for condensing the refrigerant discharged from the compressor; A cold air duct for circulating cold air into said reservoir; First and second heat exchangers connected to each other to sequentially pass refrigerant in the cold air duct; An expansion valve installed between the first heat exchanger and the second heat exchanger; A direction switching valve for selectively flowing the refrigerant flowing out of the condenser to a heat exchanger of any one of the first heat exchanger and the second heat exchanger; Air flow means for selectively flowing air in the reservoir to any one of the first heat exchanger and the second heat exchanger; A sensor for measuring an outlet temperature of the refrigerant passing through the first and second heat exchangers, a refrigerant saturation temperature, and a cold air temperature after heat exchange by the first and second heat exchangers; And a control unit for controlling the operation of the direction change valve and the air flow means in response to the temperature signal detected by the sensor. According to claim 1, wherein the cold air duct is the inlet side duct portion into which air is introduced from the reservoir, the first and second branch duct portion branching extending from the inlet side duct portion, the first and second branch duct portion The distal end portion is joined and has a discharge side duct portion for discharging air into the reservoir, And the first and second heat exchangers are respectively installed in the first and second branch duct portions, and are connected in series with each other. According to claim 2, wherein the air flow means is a blower is provided in the inlet side duct section, a first damper provided in the connection portion of the inlet side duct section and the first branch duct section, and the inlet side duct section and And a second damper installed at the connection portion of the second branch duct. The method of claim 3, wherein the control unit determines whether the difference between the temperature of the cold air heat exchanged by the first heat exchanger detected by the sensor and the refrigerant saturation temperature of the first heat exchanger is more than a preset value, If the predetermined value is less than the predetermined value, the first control mode is executed to control the direction change valve so that the refrigerant flowing out of the condenser flows to the second heat exchanger, the first damper is opened, and the second damper is closed. and, If the preset value is equal to or greater than the preset value, a second operation mode is executed in which the direction switching valve is switched so that the refrigerant flowing out of the condenser flows to the first heat exchanger, the first damper is closed, and the second damper is opened. Continuous drive showcase, characterized in that configured to. 5. The method of claim 4, wherein when the second operation mode is executed, the controller determines that the difference between the temperature of cold air heat exchanged by the second heat exchanger detected by the sensor and the refrigerant saturation temperature of the second heat exchanger is the preset value. Determine if it is above the value, If it is less than the predetermined value, the second operation mode is maintained. And a predetermined operation value, wherein the continuous operation showcase is configured to switch to the first operation mode. The air blower of claim 2, wherein the air flow means is provided at a first blower installed at a connection portion of the inlet side duct part and the first branch duct part, and at a connection portion of the inlet side duct part and the second branch duct part. Continuous operation showcase comprising a second blower. The method of claim 6, wherein the control unit determines whether the difference between the temperature of the cold air heat exchanged by the first heat exchanger detected by the sensor and the refrigerant saturation temperature of the first heat exchanger is more than a preset value, If the preset value is less than the predetermined value, the first valve is controlled to control the direction change valve so that the refrigerant flowing out of the condenser flows to the second heat exchanger, the first blower is activated, and the second blower is stopped. and, If the preset value is equal to or greater than the preset value, a second operation mode is executed in which the direction switching valve is switched so that the refrigerant flowing out of the condenser flows to the first heat exchanger, the first blower is stopped, and the second blower is operated. Continuous drive showcase, characterized in that configured to. 8. The method of claim 7, wherein when the second operation mode is executed, the controller determines that the difference between the temperature of the cold air heat exchanged by the second heat exchanger detected by the sensor and the refrigerant saturation temperature of the second heat exchanger is the preset value. Determine if it is above the value, If it is less than the predetermined value, the second operation mode is maintained. And a predetermined operation value, wherein the continuous operation showcase is configured to switch to the first operation mode. According to claim 5 or 8, The continuous operation showcase is a bypass pipe branched from the pipe connecting the compressor and the condenser and connected to the pipe connecting the condenser and the directional valve, the bypass Continuous operation type showcase further comprises a refrigerant amount control valve installed in the pipe is the opening degree is controlled by the control unit. 10. The method of claim 9, wherein the controller compares the outlet temperature of the refrigerant passing through the second heat exchanger detected by the sensor with a preset reference temperature when the first operation mode is executed, and the second operation mode is executed. And comparing the outlet temperature of the refrigerant having passed through the first heat exchanger with a predetermined reference temperature, so that the opening degree of the refrigerant amount control valve is controlled to be larger as the outlet temperature of the refrigerant is lower than the reference temperature. Showcase.

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