JP2011257025A - Control device of antisweating heater and control method of antisweating heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent securely the dew condensation of an object for antisweating with which a showcase is equipped, furthermore, the improvement of workability and energy saving is actualized, furthermore, cost is suppressed.SOLUTION: A control device 4 of an antisweating heater which controls antisweating heaters 21, 22 to prevent the dew condensation of the object section for antisweating with which the showcase capable of cooling commodities is equipped includes a temperature sensor 23 which measures the surface temperature of the object section for antisweating, and a heater control portion 32 which controls on/off-operations of the antisweating heaters 21, 22 so that the measured surface temperature measured by the temperature sensor 23 reaches a target temperature which is made to be close to the dew point temperature higher than a dew point temperature in a store in which the showcase is installed.

Description

  The present invention relates to a dew-proof heater control device and a dew-proof heater control method for preventing dew condensation in a dew-proof target part included in a showcase.

  In stores such as supermarkets and convenience stores, showcases are used for displaying products such as refrigerated foods, frozen foods, and fresh foods. As this showcase, a closed showcase having a glass door on the front surface of the case body, a showcase in which a closed showcase and a flat open showcase are combined, and the like have been developed.

  In such a showcase, dew condensation occurs in the case body due to a temperature difference between the inside and outside of the cabinet during the cold insulation operation. In order to prevent the occurrence of this dew condensation, a dew proof heater is provided in a dew proof target part, for example, a glass door or a door contact part with the glass door. Is energized all year round. As this dew-proof heater, the highest dew point temperature that can assume the surface temperature of the dew-proof target part (for example, summer daytime assumption: if the temperature is 26 ° C. and the humidity is 70%, the dew point is 20 ° C.) does not cause condensation. A dew-proof heater is selected.

  However, since the dew point temperature in the store where the showcase is installed changes greatly throughout the year, the dew prevention target part is heated to a temperature that is excessively higher than the dew point temperature in most periods except during the summer days, and wasteful energization is performed. Done. This excessive energization of the dew-proof heater causes waste of heater power, increases the cooling load in the showcase cabinet, and leads to an increase in power consumption of the refrigerator. In particular, a glass door of a closed showcase and its door stop portion often use a dew-proof heater with a large capacity of 100 W or more, and waste of heater power is large.

  Therefore, in order to suppress unnecessary energization of the dew-proof heater, a technology that changes the energization rate of the dew-proof heater, or a technology that controls the on-off of the dew-proof heater by detecting wetness of the dew-proof target using a condensation sensor (For example, refer patent document 1), the temperature etc. which monitor the temperature / humidity in a shop in real time, and control the on / off of a dew-proof heater etc. are proposed.

JP-A-11-206014

  However, in the technology for changing the current rate of the above-mentioned dew-proof heater, it is necessary to experimentally determine at what current rate the surface temperature of the dew-proof target part will be about every ° C for each showcase. Since the work is laborious, workability is reduced. In addition, there is often a difference between the experimentally determined surface temperature and the actual surface temperature in the store environment, and it is necessary to increase the corresponding safety factor, resulting in a reduced energy saving effect. .

  Moreover, in the technique using the above-mentioned dew condensation sensor, in addition to the failure of the dew condensation sensor, the system becomes expensive due to the dew condensation sensor. Similarly, the technology for monitoring the temperature and humidity in the store described above requires a humidity sensor in addition to the temperature sensor, and the system becomes expensive.

  The present invention has been made in view of the above, and its purpose is to reliably prevent the condensation of the dew prevention target part included in the showcase, and to realize improvement in workability and energy saving. It is another object of the present invention to provide a dew proof heater control device and a dew proof heater control method capable of reducing costs.

  A first feature according to the present invention is a control device for a dew proof heater that controls a dew proof heater that prevents dew condensation in a dew proof target part provided in a showcase capable of cooling a product. A temperature sensor for measuring a surface temperature, and the dew-proof heater so that the surface temperature measured by the temperature sensor is set to a target temperature that is higher than a dew point temperature in a store where the showcase is installed and close to the dew point temperature. And a heater control unit for controlling on / off of the heater.

  According to a second feature of the present invention, in the dew-proof heater control device according to the first feature described above, the heater control unit sets the target temperature for each season common to stores of the same business category. According to the information, on / off of the dew proof heater is controlled so that the surface temperature measured by the temperature sensor becomes the target temperature for each season.

  According to a third feature of the present invention, in the dew-proof heater control device according to the first or second feature described above, the heater control unit measures the surface measured by the temperature sensor only for a predetermined time of night. The on / off of the dew proof heater is controlled so that the temperature is lower than the target temperature by a predetermined temperature and higher than the dew point temperature.

  According to a fourth feature of the present invention, in the dew proof heater control device according to the third feature, the predetermined time is a time from midnight to 6:00 am, and the predetermined temperature is 2 ° C. That is.

  According to a fifth feature of the present invention, in the dew-proof heater control device according to the first, second, third, or fourth feature described above, the heater control unit performs a second operation every first predetermined time. The dew-proof heater is kept on for a predetermined time.

  According to a sixth feature of the present invention, in the dew proof heater control device according to the fifth feature described above, the first predetermined time is one hour and the second predetermined time is 10 minutes. It is.

  According to a seventh aspect of the present invention, there is provided a control method for a dew proof heater for controlling a dew proof heater for preventing dew condensation on a dew proof portion provided in a showcase capable of cooling a product, wherein the dew proof heat is controlled by a temperature sensor. A step of measuring the surface temperature of the target part, and the surface temperature measured by the temperature sensor is higher than the dew point temperature in the store where the showcase is installed and is set to a target temperature close to the dew point temperature. And a step of controlling on / off of the heater.

  According to the first or seventh feature of the present invention, the surface temperature of the dew prevention target part is directly measured by the temperature sensor, and the on / off of the dew prevention heater is switched so that the temperature becomes the aforementioned target temperature. As a result, the surface temperature of the dew prevention target part does not fall below the dew point temperature, so it is possible to reliably prevent dew condensation on the dew prevention target part, and in addition, the experiment work for each conventional showcase is omitted. Thus, workability can be improved. In addition, since it is not necessary to take a large safety factor corresponding to the difference between the experimental surface temperature and the actual surface temperature, energy savings can be improved, and a dew condensation sensor, humidity sensor, etc. are not required. So the cost can be reduced.

  According to the second feature of the present invention, the target temperature information that sets the target temperature for each season common to stores of the same business type is used, and the on / off of the dew proof heater is switched. As a result, if it is a store of the same business type, there is no need to prepare target temperature information for each showcase, so workability can be improved, and a target temperature for each season is set. Therefore, energy saving throughout the year can be realized.

  According to the third feature of the present invention, the surface temperature of the dew prevention target portion measured by the temperature sensor is lower than the target temperature by a predetermined temperature and higher than the dew point temperature in the store for a predetermined time at night. The dew-proof heater can be turned on and off. As a result, the surface temperature of the dew prevention target part is lowered from the target temperature while preventing condensation only during the night time when the dew point temperature is relatively low during the day. Power supply can be suppressed and energy saving can be realized.

  According to the fourth feature of the present invention, the aforementioned predetermined time at night is a time from midnight to 6:00 am, and the aforementioned predetermined temperature is 2 ° C. These figures are determined based on changes in the actual dew point temperature at supermarkets and convenience stores, and the surface temperature of the dew protection target area is only 2 ° C from the target temperature from 0:00 am to 6:00 am Be lowered. Thereby, even if it lowers target temperature, the surface temperature of a dew prevention object part does not become below a dew point temperature, and more energy saving can be implement | achieved, preventing dew condensation reliably.

  According to the fifth feature of the present invention, the dew proof heater is kept on only for a second predetermined time every first predetermined time. As a result, the dew-proof heater is forcibly energized, and this acts as a dew-proof safety function, so that it is possible to reliably prevent the surface temperature of the dew-proof target part from being below the dew point temperature, and more frequently ON / OFF of the dew proof heater can be suppressed.

  According to the sixth aspect of the present invention, the first predetermined time is 1 hour, and the second predetermined time is 10 minutes. These numerical values are obtained as values for which forced energization to the dew-proof heater works as a more reliable safety function, and the dew-proof heater is forcibly energized for 10 minutes every hour. As a result, it is possible to more reliably prevent the occurrence of condensation, and to reliably suppress frequent on / off of the dew-proof heater.

It is a vertical side view which shows schematic structure of the showcase which concerns on one Embodiment of this invention. It is a vertical side view which expands and shows a part of upper case with which the showcase shown in FIG. 1 is provided. It is a block diagram which shows schematic structure of the control apparatus with which the showcase shown in FIG. 1 is provided. It is explanatory drawing for demonstrating the target temperature information for dew prevention used for a convenience store. It is explanatory drawing for demonstrating the target temperature information for dew prevention used for a supermarket.

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

  As shown in FIG. 1, a showcase 1 according to an embodiment of the present invention includes an upper case 2 that is a closed showcase and a lower case 3 that is a flat open showcase. In the lower case 3, a control device 4 for controlling each part of the upper case 2 and the lower case 3 is provided.

  The upper case 2 includes a case main body 2a having an open front surface, an openable / closable door 2b covering the front surface of the case main body 2a, a product display shelf 2c and a duct 2d provided in the case main body 2a, and the inside of the duct 2d. The cooling device 2e and the circulation fan 2f are provided. The duct 2d includes a lower duct located on the bottom surface in the case body 2a, a back duct located on the back surface in the case body 2a, and an upper duct located on the ceiling surface in the case body 2a. A cooler 2e and a circulation fan 2f are installed in the upper duct.

  In the upper case 2, the cool air is blown out from the air outlet 11 a located at the front end of the upper portion of the case body 2 a by the circulation fan 2 f, cools the products on each product display shelf 2 c, and lowers the front end portion of the case body 2 a. Is sucked from the suction port 11b located at the position. Thereafter, the cool air passes through the duct 2d, is cooled by the cooler 2e, and is blown out from the blowout port 11a again. In this way, the cold air circulates through the aforementioned path.

  Here, although the glass door is used as the door 2b, it is not restricted to this, The door of materials other than glass may be used. Moreover, as the door 2b, it is possible to use various types of doors such as a hinged door (door) and a sliding door.

  The lower case 3 includes a case main body 3a whose upper surface is open, a duct 3b provided in the case main body 3a, a cooler 3c and a circulation fan 3d provided in the duct 3b. The duct 3b includes a front duct located on the front face in the case body 3a, a bottom duct located on the bottom face in the case body 3a, and a back duct located on the back face in the case body 3a. A circulation fan 3d is installed in the bottom duct, and a cooler 3c is installed in the rear duct.

  In the lower case 3, the cool air is blown out from the air outlet 12 a located at the upper end of the back surface of the case body 3 a by the circulation fan 3 d, cools the product in the case body 3 a, and the upper end portion of the front surface in the case body 3 a Is sucked from the suction port 12b located in the position. Thereafter, the cold air passes through the duct 3b, is cooled by the cooler 3c, and is blown out from the blowout port 12a again. In this way, the cold air circulates through the aforementioned path.

  Next, the upper case 2 will be described in detail. As shown in FIG. 2, a dew proof heater (first dew proof heater) 21 is provided on the frame portion of the door 2b which is a dew proof object. . In addition, a dew proof heater (second dew proof heater) 22 is provided in the frame portion of the opening of the case main body 2a, which is a dew proof object, that is, the door stop 2a1. Further, the door stop 2a1 is provided with a temperature sensor 23 for measuring the surface temperature of the door stop 2a1. As the temperature sensor 23, for example, a contact type temperature sensor is used.

  The dew-proof heater 21 is installed in the frame in a frame shape along the frame of the door 2b. Note that the dew proof heater 21 may be partially installed on the frame of the door 2b within a range where dew proof is possible. The dewproof heater 22 is affixed on the surface of the frame shape along the door stop 2a1. The dew-proof heater 22 may be partially attached to the door stop 2a1 within a range where dew-proof is possible. As these dew-proof heaters 21 and 22, for example, waterproof sheathed heaters or sheet-like heaters are used. Here, in order to attach the dew proof heater 22 to the door stop portion 2a1, by attaching the dew proof heater 22, a recess (dent) for installation is formed on the decorative plate constituting the door stop portion 2a1.

  As shown in FIG. 3, the control device 4 includes a heater contactor 31 for switching on / off of the dew proof heaters 21, 22, and energization from the power source E to the dew proof heaters 21, 22 using the heater contactor 31, A heater control unit 32 that controls on / off of the dew-proof heaters 21 and 22 and a collective centralized control panel 33 that collectively controls the upper case 2 and the lower case 3 are provided. The heater controller 32 is electrically connected to the temperature sensor 23 described above.

  The heater control unit 32 uses the heater contactor 31 to prevent the dew-proof heaters 21 and 22 in order to maintain the surface temperature of the door stop 2a1 measured by the temperature sensor 23 at a temperature higher than the dew point temperature in the store, that is, the target temperature. Is turned on and off. As this heater control part 32, a thermostat etc. are used, for example.

  The collective centralized control panel 33 performs various controls (for example, synchronous control, temperature adjustment control, defrost control, etc.) related to the operation of the upper case 2 and the lower case 3. The collective centralized control panel 33 provides various control signals and information to the heater control unit 32.

  The collective centralized control panel 33 is provided with a storage unit 33a for storing various types of information. In this storage unit 33a, target temperature information for controlling the dew proof heaters 21 and 22 is stored in advance. This target temperature information is information indicating a target temperature for one year for preventing dew condensation on the dew prevention target part. The target temperature is a temperature near the dew point temperature that is higher than the dew point temperature in the store and close to the dew point temperature.

  For example, as shown in FIGS. 4 and 5, the target temperature information includes the annual dew point temperatures of a plurality of stores for each business category such as a convenience store and a supermarket (see A1 to A5 in FIG. 4 and B1 to B3 in FIG. 5). ) To determine and set the target temperature for each season (see a in FIG. 4 and b in FIG. 5).

  FIG. 4 shows how the dew point temperature in each store of the convenience store changes from January to December. The number of sample stores is 5, and changes in the dew point temperature of each store are indicated by broken lines A1 to A5. Regarding the dew point temperature in the store, an average value is obtained every hour for each month from January to December, and the maximum average value in the same time zone is sequentially plotted in the data for each month. ing.

  A monthly target temperature a is determined based on the dew point temperature change of the polygonal lines A1 to A5. For example, the target temperature a for each month is set as close as possible to the maximum value that is higher than the maximum dew point temperature for the month period. In FIG. 4, the target temperature a is determined to be 14 ° C. from January to February, 17 ° C. from March to May, 20 ° C. from June to October, and 17 ° C. from November to December. The four periods are different seasons, and the target temperature a for each season changes according to the annual change in the dew point temperature in the store.

  FIG. 5 shows how the dew point temperature in a store changes from January to December in each supermarket store. The number of sample stores is 3, and changes in the dew point temperature of each store are indicated by broken lines B1 to B3. Regarding the dew point temperature in the store, as described above, an average value is obtained every hour for each month from January to December, and the maximum value of the average value in the same time zone in the data for each month is obtained. Plotted sequentially.

  The monthly target temperature b is determined based on the dew point temperature change of the polygonal lines B1 to B3. For example, the target temperature b for each month is set as close as possible to the maximum value that is higher than the maximum value of the dew point temperature for the month period. In FIG. 5, the target temperature b is determined to be 10 ° C. from January to February, 14 ° C. from March to April, 20 ° C. from May to October, and 14 ° C. from November to December. The four periods are different seasons, and the target temperature b for each season changes according to the annual change in the dew point temperature in the store.

  Regarding the storage of the target temperature information, the target temperature information may be stored in advance before shipment from the factory according to the business condition of the store to which the device is delivered, or the target temperature information for each business condition of the store is stored in advance. In addition, after the apparatus is delivered, one target temperature information may be selected and used from the target temperature information according to the business condition of the apparatus delivery destination store by an input operation to the input unit or the like.

  In such a configuration, the showcase 1 is normally in an operation state in which the display product is constantly cooled in order to refrigerate or freeze the displayed product, and the inside of the upper case 2 and the lower case 3 is kept cold. In this operation state, the surface temperature of the door stop 2a1 is always measured directly by the temperature sensor 23, and the dew prevention heater 21, so that the measured surface temperature of the door stop 2a1 becomes the target temperature of the current season. On / off of 22 is switched by the heater control unit 32 based on the target temperature information. Thereby, the door stop part 2a1 and the door 2b are maintained at the target temperature for every season.

  The heat generated by the dew proof heater 21 is transmitted from the periphery of the door 2b toward the inside thereof to warm the door 2b. This prevents condensation on the door 2b. Further, the heat generated by the dew-proof heater 22 is transmitted so as to spread from the periphery of the opening of the case body 2a to warm the door stop 2a1. Thereby, dew condensation is prevented from occurring in the door stop 2a1.

  Here, for example, when the temperature in the upper case 2 rises due to defrosting, carrying in goods, stopping cooling, changing the set value, etc., the surface temperature of the door stop 2a1 also rises. Energization to 21 and 22 is turned off. Therefore, excessive energization of the dew proof heaters 21 and 22 is also suppressed depending on the cooling state of the showcase 1.

  In addition to the above-described control of the dew proof heaters 21 and 22, the heater control unit 32 is for the purpose of improving energy saving, for example, the surface temperature of the door stop 2a1 only for a predetermined time at night from midnight to 6:00 am The dew proof heaters 21 and 22 are switched on and off so that the temperature is lower than the target temperature by, for example, a predetermined temperature of 2 ° C. and higher than the dew point temperature in the store.

  Further, the heater control unit 32 forcibly holds the dew proof heaters 21 and 22 on for a predetermined time of 10 minutes every predetermined time of 1 hour, for example, as a dew proof safety function. At this time, turning off the dew proof heaters 21 and 22 is prohibited.

  As described above, according to the embodiment of the present invention, the surface temperature of the door stop 2a1 is directly measured by the temperature sensor 23, and the temperature of the dew prevention heaters 21 and 22 is adjusted so that the temperature becomes the aforementioned target temperature. ON / OFF is switched. As a result, the surface temperature of the door stop 2a1 and the door 2b will not be lower than the dew point temperature, so that dew condensation can be reliably prevented, and in addition, the experiment work for each conventional showcase can be omitted. Since it becomes possible, workability | operativity can be improved. Furthermore, since it is not necessary to take a large safety factor corresponding to the difference between the experimental surface temperature and the actual surface temperature, energy saving can be improved. In particular, it is possible to realize an energy saving equivalent to the case where the dew-proof heaters 21 and 22 are controlled in accordance with the actual dew-condensation state of the dew-proof target using an expensive system with a simple configuration. And a humidity sensor or the like are not required, so that the cost can be reduced.

  Moreover, target temperature information that sets a target temperature for each season common to stores of the same business type is used, and the on / off of the dew proof heaters 21 and 22 is switched. Thereby, if it is a store of the same business condition, since the operation | work which prepares target temperature information for every showcase 1 is unnecessary, workability | operativity can be improved. Furthermore, since the target temperature for each season is set, energy saving can be realized throughout the year.

  Further, the surface temperature of the door stop 2a1 measured by the temperature sensor 23 is lower than the target temperature by a predetermined temperature (for example, 2 ° C.) only for a predetermined time at night (for example, the time from midnight to 6:00 am). The on / off of the dew proof heaters 21 and 22 is switched so as to be higher than the dew point temperature in the store. Thereby, the surface temperature of the door stop 2a1 is lowered from the target temperature while preventing condensation only during the night time when the dew point temperature is relatively low during the day. The energization to 22 can be suppressed, and more energy saving can be realized.

  Note that the above-mentioned time from 0:00 am to 6:00 am and the predetermined temperature of 2 ° C. are obtained based on changes in the dew point temperature in the store in a store of a business type such as a supermarket or a convenience store. In the business category, it is desirable to use the above-mentioned values. In particular, convenience stores often have a smaller store area than a supermarket, and are open 24 hours a day, so the environment in the store is stable and the variation from store to store is small. Even if the target temperature information stored in the unit 33a is shared by each store, condensation at each store can be reliably prevented.

  In addition, the dew proof heaters 21 and 22 are held on only for a second predetermined time (for example, 10 minutes) every first predetermined time (for example, 1 hour). As a result, the dew proof heaters 21 and 22 are forcibly energized, and this acts as a dew proof safety function, so that it is possible to reliably prevent the surface temperatures of the door stop 2a1 and the door 2b from becoming lower than the dew point temperature. Furthermore, frequent ON / OFF of the dew proof heaters 21 and 22 can be suppressed. The numerical values for 1 hour and 10 minutes described above are obtained as numerical values that act as a more reliable safety function when forced energization to the dew prevention heaters 21 and 22 is performed, and it is desirable to use those numerical values.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, some components may be deleted from all the components shown in the above-described embodiment. Furthermore, you may combine the component covering different embodiment suitably.

DESCRIPTION OF SYMBOLS 1 Showcase 2 Upper case 2a Case main body 2a1 Door contact part 2b Door 2c Merchandise display shelf 2d Duct 2e Cooler 2f Circulation fan 3 Lower case 3a Case main body 3b Duct 3c Cooler 3d Circulation fan 4 Control apparatus 11a Outlet 11b Inlet 12a Air outlet 12b Suction port 21 Dew proof heater 22 Dew proof heater 23 Temperature sensor 31 Heater contactor 32 Heater controller 33 Collective control panel 33a Storage unit E Power supply

Claims (7)

A dew proof heater control device for controlling a dew proof heater that prevents dew condensation in a dew proof target part provided in a showcase capable of cooling a product,
A temperature sensor for measuring the surface temperature of the dew protection target part;
A heater control unit that controls on / off of the dew-proof heater so that the surface temperature measured by the temperature sensor is set to a target temperature that is higher than the dew point temperature in the store where the showcase is installed and close to the dew point temperature; ,
A dew proof heater control apparatus comprising:   The heater control unit is configured to set the surface temperature measured by the temperature sensor to the target temperature for each season according to target temperature information that sets the target temperature for each season common to stores of the same business category. 2. The dew proof heater control device according to claim 1, which controls on / off of the dew proof heater.   The heater control unit controls on / off of the dew-proof heater so that the surface temperature measured by the temperature sensor is lower than the target temperature by a predetermined temperature and higher than the dew point temperature for a predetermined time at night. The dew proof heater control device according to claim 1 or 2.   4. The dew proof heater control device according to claim 3, wherein the predetermined time is a time from midnight to 6:00 am, and the predetermined temperature is 2 ° C.   5. The control of a dew proof heater according to claim 1, wherein the heater control unit keeps the dew proof heater on for a second predetermined time every first predetermined time. apparatus.   6. The dew proof heater control device according to claim 5, wherein the first predetermined time is one hour, and the second predetermined time is 10 minutes. A control method of a dew proof heater that controls a dew proof heater that prevents dew condensation in a dew proof target part provided in a showcase capable of cooling a product,
A step of measuring the surface temperature of the dew prevention target part by means of a temperature sensor;
Controlling the on / off of the dew-proof heater so that the surface temperature measured by the temperature sensor becomes a target temperature that is higher than the dew point temperature in the store where the showcase is installed and close to the dew point temperature; and
A control method for a dew-proof heater, comprising:

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