JP2003148856A - Antisweating heater control device for showcase - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antisweating heater control device for a showcase that saves on power even if after-fitted while positively preventing dew condensate. SOLUTION: This antisweating heater control device for the showcase has a dew-point temperature computing means for computing a dew-point temperature from the temperature and humidity in a store; a current carrying rate control means for controlling the current carrying rate of the antiseweating heater of the showcase provided with a refrigerating cycle, on the basis of the computed dew-point temperature; and a current carrying rate correcting means for correcting the current carrying rate on the basis of environmental conditions which have influence on the current carrying rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dew-proof heater control device for a showcase, and more particularly to a dew-proof heater control device for a showcase adapted to control the energization rate of the heater according to environmental conditions.

[0002]

2. Description of the Related Art Generally, as showcases provided in stores and equipped with a refrigeration cycle, there are showcases provided with a glass door called a reach-in showcase in addition to an open showcase. In this reach-in showcase, the dew-proof heater embedded in the vicinity of the door is always energized so that the dew condensation water is not normally generated on the glass door or the metal wall. The electricity charge applied to this dew-proof heater is
The electricity charge is 100V, which is the same as that for ordinary households, and unlike the low-voltage electricity charge applied to the reach-in showcase in the store, the unit price is double or more, so the electricity bill is high.

As a technique for reducing the electricity bill, there is a technique for calculating the dew point temperature from the temperature and humidity in the store and controlling the energization rate of the dew proof heater based on this.
No. 2 publication. The duty ratio control technology described in this publication is a duty ratio data in which the dew point temperature at room temperature is calculated from the in-store temperature and the preset humidity, and then the dew point temperature and the duty ratio to the dew-proof heater are made to correspond in advance. From the table, the duty ratio corresponding to the calculated dew point temperature is obtained.

As another improvement technique, a technique of controlling the amount of electricity supplied to the dew-proof heater is described in Japanese Patent Laid-Open No. 5-231758. The conductivity control technology described in this publication uses a temperature sensor on the glass front of each showcase, a temperature / humidity sensor in the store, and a data memory, and after detecting the temperature and humidity in front of the showcase by the temperature / humidity sensor, The dew point temperature of the glass door is calculated from that data and the data stored in the data memory, and the amount of electricity to each dew-proof heater is controlled so that the temperature detected by each temperature sensor is higher than the dew-point temperature. is there.

However, the conventional techniques described in both the above publications are limited to the temperature and humidity in the store, or those obtained by adding the temperature of the glass front surface to these, and a pre-stored data table (or data memory). Since the duty ratio is controlled by, in the case of the pre-installed method that delivers the reach-in showcase with these controls built in beforehand,
Condensation water can be prevented without problems. However, in the case of the method of retrofitting the dew-proof heater control device, it is often the case that the makers of the reach-in showcase are different or the installation position of the sensor has to be changed. The control device cannot always prevent the generation of condensed water.

Therefore, there has been a demand for a dew-proof heater control device for a showcase, which can save power even if it is retrofitted and can surely prevent dew condensation water.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned circumstances, and provides a dew-proof heater control device for a showcase, which can save power even after installation and can reliably prevent dew condensation water. The purpose is to provide.

[0008]

In order to achieve the above object, according to one aspect of the present invention, dew point temperature calculating means for calculating dew point temperature from temperature and humidity in a store, and the calculated dew point temperature. A duty ratio control means for controlling the duty ratio of a dew-proof heater of a showcase having a refrigeration cycle based on the above;
Provided is a dew-proof heater control device for a showcase, which has a duty ratio correction means for correcting the duty ratio based on an environmental condition affecting the duty ratio. As a result, power can be saved and dew condensation water can be reliably prevented even if the dew-proof heater control device is retrofitted.

According to a preferred example, the environmental condition is at least one of physical properties and installation position of a showcase, and an installation position of a temperature / humidity sensor for detecting temperature / humidity in a store. As a result, by adding a correction to this duty ratio based on the environmental conditions, it becomes possible to save power even in a retrofit-type dew-proof heater control device.

Further, according to another example, the air conditioner for air conditioning the store is switched to a dehumidifying operation mode based on the temperature and humidity in the store. As a result, the dew point temperature in the store is lowered, and the energization rate to the dew-proof heater is reduced.

According to another example, when the ventilation fan for ventilating the inside of the store is stopped, the dew-proof heater is forcibly energized. As a result, the probability of generation of dew condensation water becomes extremely low, resulting in energy saving.

According to another example, when dew condensation water is generated in the showcase, the energization control of the dew-proof heater is performed by a timer. Thereby, the condensed water can be surely extinguished.

According to another example, when the dew-proof heater fails, the air conditioner is switched to dehumidifying operation and the temperature inside the showcase is shifted upward. This reduces the generation rate of dew condensation water and facilitates maintenance such as treatment of dew condensation water.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a dew-proof heater control device for a showcase according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram of a dew-proof heater control device for a showcase according to the present invention.

As shown in FIG. 1, the store has a dew-proof heater controller 1 for a showcase according to the present invention, and two reach-in showcases 2 each having a refrigerating cycle 2c are installed. One of the showcases 2 is a frozen reach-in showcase, and the other is a refrigerated reach-in showcase. In addition, two open showcases 3 each having a refrigeration cycle 3c are installed. Furthermore, a temperature / humidity sensor 4, which detects the temperature and humidity inside the store, a ventilation fan 5, and an air conditioner 6 which air-conditions the inside of the store and can be operated in a dehumidifying mode are installed in the store. The reach-in showcase 2 and the open showcase 3 are installed at optimal places in consideration of the display effect, the flow of customers, and the places where the thermal influence from the inside of the store is difficult.

The reach-in showcase 2 is provided with a dew-proof heater 7 on a dew-proof target such as a glass door 2d. This dew-proof heater 7 is a reach-in showcase I / I.
The open showcase 3 is connected to the O unit 2a, and the open showcase I / O unit 3a is provided.
/ O unit 6a is provided, and the temperature / humidity sensor 4
Also, the ventilation fan 5 is provided with a common I / O unit 8a. The temperature and humidity sensor 4 is installed at a place where the air condition in the store can be detected most accurately.

Reach-in showcase I / O unit 2a, open showcase I / O unit 3a, air conditioner I / O unit 6a and shared I / O unit 8
a is LonWorks (Local Operati)
In software that builds ng Network,
It is connected to the computer 9 via a network by a registered trademark of Esharon Co., Ltd. in the United States. Each of the units 2a, 3a, 6a, and 8a has a CPU, a RAM, a ROM, a network function, and I corresponding to LonWorks.
A microcomputer chip with an / O function is built in, which enables the use of LonWorks
By constructing a network utilizing this LonWorks (registered trademark of Esharon Co., Ltd. in the United States), various models manufactured by different manufacturers can be integrally controlled.

As shown in FIG. 2, the arithmetic and control unit of the computer 9 is a dew point temperature calculating means for calculating the dew point temperature from the temperature and humidity in the store, and the dew-proof heater 7 based on the dew point temperature.
And a duty factor correction means for correcting the duty factor based on the environmental conditions in the store. Further, the table memory of the memory stores data, patterns, etc. obtained in advance by experiments or the like.

Therefore, the control of the refrigeration cycle 2c, the dew-proof heater 7, the refrigeration cycle 3c, the temperature / humidity sensor 4, the ventilation fan 5 and the air conditioner 6 by the computer 9 is performed by the reach-in showcase I / O unit 2a and the open showcase I. / O unit 3a, I / O unit 6 for air conditioner
a and the shared I / O unit 8a, according to the control procedure programmed in the computer 9 in advance,
Further, it is performed by input from the input means 10 provided in the computer 9 as needed. In particular, the computer 9
The dew-proof heater 7 is controlled based on the control parameters stored in the table memory, and the parameters can be easily changed by the computer 9.

Next, a first control method using the dew-proof heater control device for a showcase according to the present invention will be described with reference to the control flow chart shown in FIG.

The temperature / humidity sensor 4 installed in the store detects the temperature and humidity, and the computer 9 calculates the dew point temperature (S
1). The difference between the desired in-store environmental condition and the actual environmental condition is automatically or manually recognized and compared (S2). A correction value is calculated by this comparison (S3). The calculation of the correction value is performed by classifying each change as shown in Table 1 stored in the data memory of the computer into three levels of large, medium and small, and recognizing which part the actual environmental condition falls into.

The control dew point temperature is calculated (S4). An energization pattern is selected based on the calculated control value (corrected dew point temperature) (S5). The data memory of the computer 9 stores the relationship between the dew point temperature and the energization pattern which is determined in advance under the desired environmental conditions and shown in Table 2, and the energization pattern is selected from this correlation.

The dew-proof heater 7 is controlled through the reach-in showcase I / O unit 2a (S6). The dew-proof heater 7 is controlled based on the selected energization pattern. After the selection of the energization pattern, the temperature and humidity inside the store are detected again, and the same procedure is repeated.

One cycle of energization is completed (S7). Here, as the environmental conditions, for example, in addition to the temperature and humidity in the store, physical properties of the showcase, that is, the material and thickness of the door, the installation position of the temperature and humidity sensor, the installation position of the showcase, and the like can be mentioned. Since the temperature and humidity are distributed in the glass door 2d and inside the store, if the material and thickness of the showcase 2, the installation position of the temperature and humidity sensor 4, and the installation position of the showcase 2 are different, the validity of the detected temperature is different. However, by reflecting this difference in the control, the dew condensation water can be surely prevented even in the retrofitting method of the dew-proof heater control device.

As described above, the dew point temperature is calculated from the temperature and humidity in the store, the energization rate of the dew-proof heater is controlled based on this dew point temperature, and the energization rate is corrected on the basis of environmental conditions to obtain the optimum energization. As a result, power can be saved, and dew condensation water can be surely prevented even in a retrofit-type dew-proof heater control device.

Furthermore, FIG. 6 shows a second control method using the dew-proof heater control device for a showcase according to the present invention.
A description will be given along the control flowchart shown in FIG. The second control method also controls the air conditioner.

The first temperature and humidity value in the store is set in advance.
The dew point temperature in the store detected by the temperature and humidity sensor 4 and the first
The set values of are compared (S11). When the dew point temperature in the store is equal to or higher than the first set value (No), the computer 9 causes the air conditioner 6 to operate in the dehumidifying mode via the air conditioner I / O unit 6a (S12). The dew point temperature for control is calculated (S13). An energization pattern is selected based on the calculated control dew point temperature (S14). For the energization control of the dew-proof heater 7, the dew-proof heater is controlled by selecting an energization pattern that is one rank lower than the energization pattern selected from Table 2 based on the calculated control dew point temperature and has a shorter energization time.

When one cycle of the energization pattern is completed (S15), the temperature / humidity sensor 4 detects the dew point temperature in the store, and the dew point temperature falls below a preset second set value (No. ), The above control for shifting one rank is stopped, and non-shift normal energization control is performed (S16).

By dehumidifying the inside of the store using the air conditioner 6, the dew point temperature inside the store is lowered, and the energization rate to the dew-proof heater 7 can be reduced.

In S11, if the detected dew point temperature is lower than the first set value (Yes), normal energization control is immediately performed. This is because the dehumidifying range of the air conditioner 6 has a limit, and the lower the dew point temperature, the more the air conditioner 6
This is because the dehumidifying effect due to is reduced. The dehumidification-enabled mode includes cooling operation as well as dehumidifying operation, and may be switched to cooling operation when the dew point temperature in the store is high and dehumidifying operation when the temperature is lower than that.

Thereafter, the steps S4 to S7 are performed (S17 to S20).

A third control method using the showcase dew-proof heater control device according to the present invention will be described with reference to the control flowchart shown in FIG. The third control method is to control the dew-proof heater in consideration of the operating state of the ventilation fan.

The computer 9 determines via the shared I / O unit 8a whether or not the ventilation fan 5 installed in the store is in a controlled state (S21). The stop of the ventilation fan 5 is detected (S22). When detecting that the ventilation fan 5 is stopped (Yes), the computer 9 changes the control method of the dew-proof heater 7 to the continuous energization mode via the reach-in showcase I / O unit 2a (S23). Ventilation fan 5
(No), the computer 9 re-detects the dew point temperature in the store through the shared I / O unit 8a and detects the forced energization pattern of the dew-proof heater 7 (S).
24).

The ventilation fan in the store is always in operation mainly for removing odors such as oden. However, in the case of a store that controls the ventilation fan on / off with a smell sensor (air quality sensor) that has been introduced in recent years, the ventilation fan is turned off based on the odor or the temperature of a specific component contained in the air. , Steam from the oden stays in the store and raises the dew point temperature in the store. On the other hand, water vapor has a property of moving to a low temperature portion where the water vapor pressure is low, that is, a reach-in door portion, and there is a period for detecting the dew point temperature used for controlling the energization of the dew-proof heater. Condensation water is more likely to be generated on the showcase door. Once the condensed water is generated, it takes a lot of time to energize it. On the other hand, in the dew-proof heater control device 1, the probability of dew condensation water generation is extremely low, and as a result,
It saves energy.

The fourth control method using the dew-proof heater control device for a showcase according to the present invention will be described with reference to the control flowchart shown in FIG. The fourth control method uses a timer to control the energization of the dew-proof heater when dew condensation water occurs.

The temperature and humidity sensor 4 installed in the store detects the temperature and humidity, and the computer 9 calculates the dew point temperature (S
31). The dew point temperature for control is calculated (S32). Above S
The dew point temperature for control is calculated in the same procedure as 2 and S3. An energization pattern is selected from the patterns shown in Table 2 based on the calculated control value (corrected dew point temperature) (S33). It is determined whether or not condensed water is generated (S34).

The energization control of the anti-condensation heater 7 is usually performed on the assumption that no condensed water adheres from the viewpoint of preventing the generation of condensed water. However, if dew condensation occurs on the door or the like for some reason, the normal energization control cannot eliminate the attached dew condensation, and the floor near the reach-in showcase is covered with water. When an experiment was conducted to eliminate the condensed water, it was found that the condensed water can be eliminated by keeping the temperature of the door or the like at the dew point temperature in the store for about 2 hours. The time required for this disappearance is
Depends on the amount of condensed water droplets.

The amount of condensed water is confirmed (S35). S3
4, when it is confirmed that condensed water is generated during the normal dew-proof heater control, based on the amount of generated condensed water, for example,
Any one of three types of energization times of long, medium and single hours is selected (S36 to S38). Whether or not the condensed water disappears
It may be confirmed by a clerk, or automatically by a camera or the like. It is confirmed that the forced energization time has ended (S39). When the forced energization time ends, the dew condensation water disappearance is confirmed, and when the dew condensation water disappears, the normal dew-proof heater control is resumed.

When it is judged in step S34 that no dew condensation water is generated (No), the dew-proof heater 7 is controlled (S40). The dew-proof heater 7 is controlled based on the selected energization pattern. One cycle of energization ends (S4
1).

As described above, when the dew condensation water is generated in the showcase 2, the dew condensation water can be surely extinguished by controlling the energization of the dew-proof heater 7 by the timer.

A fifth control method using the dew-proof heater control device for a showcase according to the present invention will be described with reference to the control flowchart shown in FIG. The fifth control method is to detect the failure of the dew-proof heater and control the air conditioner.

It is determined whether or not the dew-proof heater 7 is out of order (S
41). I / O unit 2a for reach-in showcase
When the computer 9 detects the failure of the dew-proof heater 7 through the (Yes), the computer 9 switches the dehumidifying operation mode of the air conditioner 6 to dehumidify the inside of the store (S4).
2). The control temperature of the reach-in showcase 2 in which the dew-proof heater 7 has failed is shifted to the maximum control upper limit range (S
43).

Normally, a repair person generally comes to the store about 90 minutes after the occurrence of a failure and repairs it. Therefore, the rate of generation of condensed water in the reach-in showcase 2 can be reduced only during this period, and the condensed water can be reduced. Maintenance such as processing can be facilitated.

[0045]

According to the dew-proof heater control device for a showcase according to the present invention, it is possible to provide a dew-proof heater control device for a showcase capable of saving power even after installation and reliably preventing dew condensation water. You can

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a dew-proof heater control device for a showcase according to the present invention.

FIG. 2 is a control system diagram of a dew-proof heater control device for a showcase according to the present invention.

FIG. 3 is a control flowchart for use in a dew-proof heater control device for a showcase according to the present invention.

FIG. 4 is a correction table diagram used in a control method using a dew-proof heater control device for a showcase according to the present invention.

FIG. 5 is an energization pattern selection table used in a control method using a dew-proof heater control device for a showcase according to the present invention.

FIG. 6 is a control flowchart used in the dew-proof heater control device for a showcase according to the present invention.

FIG. 7 is a control flowchart used in the dew-proof heater control device for a showcase according to the present invention.

FIG. 8 is a control flowchart used in the dew-proof heater control device for a showcase according to the present invention.

FIG. 9 is a control flow chart used in the dew-proof heater control device for a showcase according to the present invention.

[Explanation of symbols]

1 Dew-proof heater controller for showcase 2 reach-in showcase 2a I / O unit for reach-in showcase 3 open showcase 3a I / O unit for open showcase 4 temperature and humidity sensor 5 ventilation fan 6 air conditioners 6a I / O unit for air conditioner 7 Dew-proof heater 8a Shared I / O unit 9 computers 10 Input means

Claims (6)

[Claims] 1. A dew point temperature calculating means for calculating a dew point temperature from temperature and humidity in a store, and a duty ratio control for controlling a duty ratio of a dew-proof heater of a showcase having a refrigerating cycle based on the calculated dew point temperature. A dew-proof heater control device for a showcase, comprising: means and a duty ratio correction means for correcting the duty ratio based on an environmental condition affecting the duty ratio. 2. The environmental condition is at least one of a physical property and an installation position of a showcase, and an installation position of a temperature and humidity sensor for detecting temperature and humidity in a store. Dew-proof heater control device for showcase. 3. The dew-proof heater control device for a showcase according to claim 1, wherein an air conditioner for air conditioning the inside of the store is switched to a dehumidifying operation mode based on the temperature and humidity inside the store. 4. The dew proof of the showcase according to claim 1, wherein the dew proof heater is forcibly energized when the ventilation fan for ventilating the store is stopped. Heater control device. 5. The dew-proof heater control for a showcase according to claim 1, wherein when the dew condensation water is generated in the showcase, the energization control of the dew-proof heater is performed by a timer. apparatus. 6. The show according to claim 1, wherein when the dew-proof heater fails, the air conditioner is switched to dehumidifying operation and the temperature inside the showcase is shifted upward. Dew-proof heater controller for the case.