JPH0325705B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an indoor temperature control method that enables effective refrigeration operation and saves energy.

To cool the room, turn on the refrigerator compressor,
The temperature is controlled by turning it off, and the difference in temperature when it is turned on and off, that is, the temperature range, is called the dead zone of the refrigerator. This dead zone has a great effect on power consumption and the life of the refrigerator.If the dead zone is made large, unnecessary supercooling will occur and power will be wasted; conversely, if the dead zone is made small, This results in short cycle operation, which significantly shortens the life of the motor and electrical components. However, in conventional cooling methods, once the dead zone is set, it remains fixed, so even if the temperature drop gradient changes due to load fluctuations, etc.
The refrigerator was only turned off when the set lower limit temperature was reached, resulting in unnecessary supercooling operation.

The present invention is to reduce the loss in continuous operation due to temperature saturation by automatically correcting the dead zone in refrigerator operation according to the state of indoor temperature drop. The present invention will be explained.

FIG. 1 shows the case where the maximum dead zone is set at 0°C to -2.0°C. The desired temperature is 0°C, and when the room temperature reaches this temperature, the refrigerator is turned on. l ₁ , l ₂ . . . l ₇ are temperature gradient curves, and in the conventional method in which the dead zone is not automatically corrected, the refrigerator does not stop (turn off) until the temperature in the room reaches -2.0°C, marked with an x. Therefore, the refrigerator stops approximately 15 minutes after the start of cooling for temperature gradient curve _l2 , approximately 35 minutes for _l3 , approximately 60 minutes for _l4 , and several hours for _l6 .

However, in order to control the desired temperature to 0℃, -
It is not necessary to operate the refrigerator until the temperature reaches 2.0℃, and experiments have shown that in the case of each of the temperature gradients mentioned above, it is sufficient to stop the refrigerator when the off-point temperature indicated by the white circle is reached. It was obtained from both calculations. That is, the off-point of the white circle is a correction point for the stop timing of the refrigerator at each temperature gradient, and is regarded as the off-time temperature in each temperature gradient curve. However, the correction point is
It can also be seen as having a correlation with the operating time of the chiller after it starts cooling, and by programming the chiller to operate based on this, overcooling operation can be prevented and power consumption can be saved. can.

For example, when the temperature gradient curve is l ₃ , the refrigerator would normally stop after about 36 minutes, but with the correction, it will stop after 24 minutes, and similarly, when the temperature gradient curve is l ₄ , it will stop after about 60 minutes. After 30 minutes, it will be stopped after about 50 minutes instead of 100 minutes in case of _l5 , and the operating time of the refrigerator can be significantly shortened.

However, in the method of this embodiment, the locus of the white circle correction off point becomes a curve as shown by the two-dot chain line, and the calculation for creating the off point program becomes complicated.

However, in reality, even if the correction off points for each temperature gradient curve are given as indicated by black dots, and the line connecting each correction point becomes a straight line, the effect is different from that of the correction using the white dot off points. There is almost no real difference between the two. Therefore, by making each correction off point a straight line like the black circle correction point, the correction off point can be understood as a linear function of the operating time, which facilitates programming of operation control. .

At this time, the operation control using the correction off point is the cooling operation time in the maximum dead zone after the start of operation, that is, the non-correction time Tn (usually about 15 minutes or more)
Do it after the time has passed.

Figure 2 also shows the case in which the off-point correction of the refrigerator is considered as a linear function of the operating time of the refrigerator. For example, in the same figure, the uncorrected time is 15 minutes,
Thereafter, the correction point is increased by 0.1°C every 3 minutes. Therefore, in the same figure, when the temperature drop line is l ₂ , the refrigerator stopped after 30 minutes without correction, but after correction, the refrigerator stopped 24 minutes after the black circle point, and as shown below. The temperature drop line for l ₃ was 45 minutes later, whereas the temperature drop line was 31 to 2 minutes after the black circle point, and for l ₆ , it was 90 minutes later, but the refrigerator was stopped 45 minutes after the black circle point.

The above correction is performed after the indoor temperature enters the dead zone, and is not performed while the room is being cooled from point a to point b, which is the set temperature, as shown in Figure 3. Off point correction is performed after this point.

In the present invention, the temperature difference in the width of the dead zone within the temperature range of the refrigerator is divided finely, and the operation is controlled using this value as a function of the operating time. Therefore, as shown in Fig. 5, the lower limit value is Automatic correction based on time can shorten the operating time by _T1 hour, and in the case of a freezer with an internal temperature of 2, where the internal temperature trend is slower than that of internal temperature 1, compression operation is better than with conventional means. The time is significantly reduced to T ₂ hours.

Although the above is an example of the case where the compressor is turned on and off, the method of the present invention can also be used for unloading operation of the compressor, which is shown in FIG.

In the figure, when the indoor temperature reaches the upper limit temperature of the dead zone, that is, the set temperature at point b, unloading control of the compressor is performed. At this time, the No. 1 compressor (or the first cylinder) is controlled by the temperature command 1, but the No. 2 compressor (or the second cylinder)
is not activated during the output prohibition flag, and is activated only when the output prohibition flag is cleared, thereby preventing unnecessary overcooling and short cycle operation.

As described above, according to the method of the present invention, by automatically correcting the dead zone, in other words, when the cooling capacity is large, the dead zone is increased to prevent short cycle operation, and when the cooling capacity is balanced, the dead zone is This makes it possible to prevent wasteful overcooling due to temperature saturation and thereby shorten the compressor's wasteful operating time, allowing for cooling operation that saves power and energy.

In addition, the position of the lower limit temperature point can be changed almost steplessly, so even if the temperature gradient varies depending on the outside air temperature or indoor temperature load, the optimal lower limit temperature point can always be automatically set, and the product It has the advantage that it can be used in all kinds of equipment, such as refrigerators in markets where there is a lot of loading and unloading, and air conditioners in buildings.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the temperature drop curve and the corrected off point of the compressor in the method of the present invention, FIG. 2 is a diagram showing another example regarding the same relationship, and FIG. FIG. 4 is a diagram showing the case of unloading control.
Further, FIG. 5 is a diagram showing a reduction in operating time. In the figure, l ₁ , l ₂ ... l ₇ ... temperature drop line, white circle dots and black dots ... compressor correction off point.

Claims (1)

[Claims] 1. A temperature control method in which refrigeration equipment is operated at the set temperature and stopped at the lower limit temperature so as to maintain the temperature in the room to be cooled within a dead zone between the set temperature and a lower limit temperature lower than the set temperature, An indoor temperature control method, characterized in that the lower limit temperature point is raised in direct proportion to the elapse of time since the start of operation of the refrigeration equipment after an uncorrected time has elapsed since the start of operation of the refrigeration equipment.