JPS5883169A - Duty-cycle operation control method for freezing refrigerator - 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 The present invention relates to a duty cycle operation control method for a freezing/refrigerating apparatus that aims to save energy in the freezing/refrigerating apparatus.

Conventional duty cycle operation has a cycle of, for example, 32 minutes, and a period of time, such as 4 minutes or 6 minutes, is determined depending on a certain load condition, during which the cooling operation is stopped. Conventionally, this cooling operation time has been set based on a high load standard to maintain temperature, regardless of the ambient temperature or fluctuations of the cooling equipment, but for example, the load of an open showcase may vary depending on the season. , when the cooling operation is stopped due to changes in ambient conditions, the temperature inside the open showcase increases as shown in Figure 1: 1 at high load, 2 at medium load, and 3 at low load. They are each very different.

Therefore, at high load, the duty cycle increases to 11
If the temperature rise when the cooling operation is stopped for 1 minute is θ1 as shown in Figure 1, then at low load 3, it is possible to stop the cooling operation for 13 minutes to reach the same temperature rise value inside the refrigerator. .

That is, as shown in FIG. 2, as the ambient conditions decrease, the time during which the cooling operation can be stopped in the duty cycle increases.

On the other hand, if the cooling operation stop time is set to, for example, TI based on a high load and remains constant regardless of load fluctuations, the chiller will consume extra energy by the amount of TI. (1゜This invention has been made in view of the above points,
A duty cycle operation control method for a refrigeration/refrigeration system that makes it possible to appropriately reduce the energy consumption of a refrigerator even in response to changes in load conditions by performing duty cycle operation that corresponds to changes in the load on the cooling equipment. The purpose is to provide

Hereinafter, embodiments of the duty cycle operation control method for a freezing/refrigerating apparatus according to the present invention will be described.

In general, temperature control for cooling equipment such as open showcases involves blocking and distributing the flow of refrigerant to the cooler installed in the cooling equipment by opening and closing valves such as solenoid valves at intervals commensurate with the load on the equipment. On-off control is carried out to keep the temperature cool.

In this case, as the load decreases, the ratio of the time during which the solenoid valve is open to that time, that is, the time during which cooling operation is performed (hereinafter referred to as the operation rate), decreases. Normally, changes occur as shown in Figure 3.

Therefore, by detecting the on-off state of the solenoid valve that controls the flow of refrigerant to the showcase and calculating the operating rate within a certain time, as shown in Figure 3, the surrounding environment at that time can be calculated. Load conditions can be estimated.

On the other hand, in cooling equipment, especially in open showcases, there are individual differences in cooling characteristics even among the same model, and differences in operating rates occur even under the same ambient conditions. Therefore, in a group of showcases connected to one refrigerator, the operating rate is as shown in FIG. 4, for example, with respect to the ambient conditions.

In other words, among the showcase groups, the one with the worst cooling characteristics, and therefore the highest operating rate, is 1-1 in Figure 4.
', and the one with the lowest operating rate is shown in Figure 4 2-2.
The operating rate characteristics of other showcases are between 1-1' and 2-2'. In other words, the operation rate characteristics of the showcase group have a band width as shown in FIG. 4 with respect to the ambient conditions.

Here, when the ambient condition is a, the operation rate of the showcase group is measured between the maximum and minimum bandwidth, that is, from A to A', but the operation stop time of the duty cycle is determined. If we take A, which is the maximum operation rate of the showcase group, as the operation rate for The rise in temperature inside the refrigerator can be suppressed within the rise value determined by the operating rate.

Therefore, the temperature of the items inside the refrigerator can be maintained appropriately. Furthermore, as shown in Figure 4, the characteristics of this maximum operating rate decrease as the ambient conditions decrease, and therefore the cooling operation stop time also increases, allowing for appropriate reduction of chiller energy consumption in response to fluctuations in ambient conditions. It is possible to aim for

As described above, according to the duty cycle operation control method for a freezer/refrigerator according to the present invention, the duty cycle is adjusted according to the highest operating rate among the cooling equipment group connected to one refrigerator. Since the operation stop time of the cycle is adjusted, the energy consumption of the refrigerator can be appropriately reduced even in response to changes in the load state, and the temperature inside the refrigerator can be maintained.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the temperature rise characteristics inside the refrigerator when cooling operation is stopped for showcases, etc. Figure 2 is a diagram showing the cooling operation stop time based on high load conditions, and Figure 3 is a diagram showing the temperature rise characteristics in a showcase etc. when cooling operation is stopped. FIG. 4 is a diagram showing the characteristics of the operating ratio of the showcase group with respect to the ambient conditions for explaining the duty cycle operation control method of the freezing and refrigerating apparatus according to the present invention. Agent Makoto Kuzuno - Figure 1 (0C)

Claims (1)

[Claims] In a refrigeration system that performs a duty cycle operation in which the refrigeration machine or the refrigeration equipment group consists of a refrigeration machine and a group of cooling equipment such as an open showcase, the cooling operation of the refrigeration machine or the refrigeration equipment group is repeated at predetermined intervals. A duty cycle operation control method for a freezing and refrigerating device, characterized in that the duty cycle operation stop time is adjusted in accordance with the device with the highest operating rate among a group of cooling devices connected to one refrigerator.