JPS6226471A - High-humidity showcase - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a high-humidity showcase, and in particular, an inverter is introduced in order to effectively carry out moisture adhesion and re-evaporation necessary to obtain high humidity. This invention relates to a compressor with variable capacity.

[Technical Background of the Invention] Generally, the structure of a high humidity showcase is as shown in FIG. It is. During cooling, the flow of cold air is circulated within the cooling chamber by the fan 4 as shown by the arrow, but even when the fan 4 is stopped, the fan 4 continues to rotate, and this wind accelerates the evaporation of moisture, resulting in the show. Maintain high humidity inside the case. That is, in order to obtain high humidity in the high humidity showcase, a method is adopted in which moisture adhering to the evaporator 3 during cooling is evaporated while the evaporator 3 is stopped.

As shown in FIG. 6, this conventional refrigeration cycle is as follows: compressor 1 → condenser 2 → capillary tube 5 → evaporator 3 → pressure 11i! 1fi1, and a humidifying tray 6 and a heater 7 are provided in the cooling room to supplement humidity when the outside air is low temperature.

The operating rate of the compressor 1 is controlled based on the information from the internal temperature sensor 8 to maintain the internal temperature at a target value, and the energization of the heater 7 is controlled based on the information from the external temperature sensor 9. It will be done.

By the way, as shown in FIG. 9, the relationship between the outside temperature and the heat leakage rate is such that the higher the outside temperature, the greater the amount of leakage.

For this reason, the operating situation when the outside temperature is high is as shown in Figure 7 (a), but when the outside temperature is medium, the amount of leakage decreases and the operating rate becomes low (Figure 7 (b)). When the temperature further decreases, the OFF time of the compressor becomes longer and the time for moisture adhesion becomes shorter, so the water in the humidifying tray 6 is evaporated by the heater 7 to compensate for the humidity (FIG. 7(C)).

As described above, in the conventional system, the operating rate varied greatly depending on changes in the outside temperature.

[Problem with background technology 1 ゛ However, as a condition for exceeding high humidity by 1, the 8th
As shown in the figure, since the operating rate of the compressor needs to be about 45 to 55%, conventional systems in which the operating rate changes depending on changes in outside temperature have had the following problems.

(1) Since the operating rate changes with changes in outside temperature, the operating (outside air) temperature range that can maintain high humidity inside the refrigerator is narrow.

(2) The power loss of the humidifying heater, which is turned on when the outside temperature is low, is large, increasing electricity bills.

(3) Since the operating rate of the compressor is determined based on the maximum load, 0N-OFF will occur frequently during light loads.
It has a negative impact on the durability of the compressor.

[Object of the invention] The object of the present invention is to solve the above problems by controlling two operation cycles of cooling and heating with an inverter.
To provide a highly durable high humidity showcase capable of efficiently obtaining stable high humidity regardless of outside temperature.

[Summary of the Invention] The present invention provides a refrigeration cycle with an inverter that controls the frequency of the compressor, a heating pipe that guides hot gas from the compressor to the evaporator during heating, and a system that lowers the frequency during cooling and increases the frequency during heating. The present invention is characterized in that it includes a controller that sends a control signal to the inverter.

As a result, the internal temperature can be controlled by changing the frequency of the compressor without turning it into 0N10FF, and at the same time, during cooling when the outside temperature is low, the frequency is lowered to ensure sufficient adhesion time for moisture to adhere to the evaporator. Similarly, during heating when the outside temperature is low, hot gas is flowed directly into the evaporator to heat the evaporator, and the frequency is increased to actively re-evaporate moisture adhering to the evaporator.

[Embodiments of the Invention] Examples of the present invention will be described below based on FIGS. 11 to 5.

FIG. 1 shows an example of the refrigeration cycle configuration of the high humidity showcase of the present invention. As shown in the figure, the discharge side of the compressor 11 and the evaporator 1
A heating pipe 20 is connected between the inlet side of the compressor 11 and the inlet side of the compressor 11, and the hot gas is guided directly from the compressor 11 to the lid R unit 13, bypassing the condenser 12. A humidifier 1116 is provided in close contact with the heating pipe 20, and this humidifier plate 16
Water may be supplied to the tank only when the outside air is low, and the water may be supplied from outside, for example. Further, a two-way valve 21 made of a solenoid valve is interposed in the heating pipe 20, and the two-way valve 21 is switched to open or close based on information from the internal temperature sensor 18.

In addition to the internal temperature sensor 18 described above, the sensors include an outside air temperature sensor 19 that detects the temperature of outside air, and an evaporator temperature sensor 22 attached to the evaporator 13.

On the other hand, the compressor 11 is provided with an inverter device 23,
This inverter device includes an inverter 24 that controls the power frequency of the compressor 11 according to a control signal, the chamber temperature sensor 18, the outside air temperature sensor 19, and the evaporator temperature sensor 2.
2, and a controller 25 that sends a control signal to the inverter 24 based on the information of 2.

Now, the operation of the above configuration will be explained based on the functions of the controller 25 shown in the flowchart of FIG.

In the first stage of the flowchart, the rotation speed of the compression ring is changed by an inverter in response to changes in outside temperature, and in the second stage, capacity variable control is performed to change the rotation speed in response to the difference between the internal temperature and the evaporation temperature.

That is, in the first stage of the flowchart, it is determined how much the outside air temperature Rt is, and if the outside air is high temperature, the cooling frequency [is increased, and the heating frequency r is low, or the internal temperature is stopped. Avoid raising the temperature more than necessary. Here, the cooling time and heating time refer to two operation cycles performed in the middle stage of the flow.

Conversely, when the outside air is low temperature, the cooling frequency is lowered to ensure sufficient time for moisture to adhere to the evaporator, while the heating frequency is raised to increase re-evaporation efficiency.

FIG. 3 shows the changes in the cooling frequency and the heating frequency controlled in this manner with respect to the outside temperature.

In the middle stage of the flowchart, switching between two operation cycles is performed. That is, it is determined whether the internal temperature Δ[ is lower than the target value (or not), and if it is lower than the target value, it is determined that heating is necessary, and the two-way valve 21 is switched, the heating pipe 20 is opened, and the hot gas is transferred to the evaporator. 13□. This operation cycle is the heating time, and while this actively promotes the re-evaporation of the moisture adhering to the evaporator 13 during cooling, the humidifying tray 16 that is in close contact with the heating pipe 20
To maintain high humidity inside a refrigerator by heating and evaporating the humidifying water put in the refrigerator without using a heater. Moreover, if t to i degree inside the refrigerator is higher than the target value, the process proceeds to the cooling operation cycle, that is, to the latter part of the flowchart.

In the latter part of the flowchart, the internal temperature Δ℃ and the evaporation temperature E
The difference △T from t is determined, and when the internal temperature A [ approaches the evaporator temperature Et, that is, as the difference becomes smaller, the frequency is gradually reduced to increase the time for moisture to adhere to the refrigerator. Bring the internal temperature closer to the target value. FIG. 9 shows this.

As a result of all the above-mentioned flows, the humidity and temperature inside the refrigerator when the outside air is high, medium, and low are shown in (a) to (C) in Figure 2.
As shown in Fig. 1, stable high humidity can be maintained even when the outside temperature changes, and the evaporation efficiency, which otherwise tends to decrease, can be increased even when the outside temperature is low. This is made possible by adding a heating cycle to the cooling cycle, making the compression compensation a variable capacity type controlled by an inverter, and controlling the inverter based on the temperature inside the refrigerator, outside the refrigerator, or the evaporator.

[Effects of the Invention] To summarize, the present invention exhibits the following excellent effects.

(1) As the outside temperature decreases, the inverter lowers the frequency when cooling, and when cooling is stopped, switches to heating and increases the frequency, thereby adopting operation rate control that does not rely on an inverter. Unlike conventional methods, where the time for moisture to adhere to the evaporator during cooling is too short, or where the moisture attached to the evaporator when cooling is stopped is simply re-evaporated by a fan, the time for moisture to adhere to the evaporator during cooling is shorter. In addition to ensuring sufficient humidity, the evaporator is actively heated when the cold riI is stopped, increasing the re-evaporation efficiency, so a stable high humidity can be obtained regardless of the outside temperature.

(2) By installing a heating pipe that leads the hot gas directly from the compressor to the evaporator, unlike conventional systems that require heat for heating, electrical power for heating is not required. Energy saving can be achieved.

(3) By adopting an inverter, frequent 0N10 FF of the compressor can be avoided, improving the life of the compressor.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle configuration diagram showing an actual example of the high humidity showcase of the present invention, Fig. 2 is a diagram of internal humidity and temperature characteristics with outside temperature as a parameter based on the refrigeration cycle of Fig. 1;
FIG. 3 is a frequency characteristic diagram for the outside temperature, FIG. 4 is a frequency characteristic diagram for the difference between the internal temperature and the evaporator temperature, and FIG. 5 is a 70-diagram diagram explaining the various functions of the controller. Figure 6 is a configuration diagram of the refrigeration cycle of a conventional high-humidity showcase. Figure 7 is a diagram of the internal humidity and temperature characteristics based on the refrigeration cycle in Figure 6 using outside temperature as a parameter. Figure 8 is a diagram of ensuring high humidity. FIG. 9 is a characteristic diagram showing the amount of leakage with respect to outside temperature, and FIG. 10 is a schematic cross-sectional structural diagram of a high-humidity showcase common to the present invention and the conventional one. In the figure, 11 is a compressor, 12 is a condenser, 13 is an evaporator, 1
6 is a humidifying dish, 18 is an internal temperature sensor, 19 is an outside temperature sensor, 20 is a heating pipe, 22 is an evaporator temperature sensor, 2
4 is an inverter, and 25 is a controller. Patent applicant Toshiba Corporation Patent attorney
Nobuo Kinutani Figure 5 Figure 7

Claims (2)

[Claims] (1) In a high humidity showcase equipped with a refrigeration cycle that re-evaporates moisture adhering to an evaporator during cooling when cooling is stopped, an inverter that variably controls the power frequency of a compressor in the refrigeration cycle according to a control signal; A heating pipe bypasses the condenser and directs the hot gas from the compressor to the evaporator to heat it during heating when the internal temperature is below the target value, and a heating pipe that heats the hot gas from the compressor directly to the evaporator. and a controller that sends a control signal to the inverter that lowers the frequency and conversely increases the frequency during heating. (2) The controller compares the internal temperature and the evaporator temperature during cooling, and sends a control signal to the inverter to lower the frequency as the temperature difference becomes smaller. The high humidity showcase described in item 1.