JPH0343552B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to an ice making heat storage system, and particularly to a night time ice making heat storage device suitable for effectively utilizing nighttime electricity and reducing power consumption.

[Background of the invention]

In conventional ice-making thermal storage systems, the ice-making time is constant, so when the load was heavy, the ice would melt during the day and the temperature inside the heat storage tank would rise. Therefore, in order to cool the air conditioner, it is necessary to restart the operation of the refrigerator.
The drawbacks were that the refrigerator had to run for a long time during the day and consumed a lot of electricity.

[Purpose of the invention]

This invention was made based on the above-mentioned matters, and aims to effectively utilize nighttime power and reduce power consumption.

[Summary of the invention]

The feature of this invention is that the refrigerator is not operated during the daytime when power consumption is concentrated, and ice making heat storage operation is performed at night in order to effectively utilize nighttime power.
The aim is to set the operating time of the refrigerator for the next ice making heat storage in proportion to the amount of ice in the heat storage tank at the end of air conditioning, thereby minimizing power consumption.

[Embodiments of the invention]

Embodiments of the nighttime ice making heat storage system according to the present invention will be described below with reference to the drawings.

The configuration of the nighttime ice making heat storage system is the same as the conventional ice making heat storage system, as shown in Figure 1.
It consists of a cooling tower 1, a refrigerator (a condenser 2, an expansion valve 3, an evaporator 4, a compressor 5), and a heat storage tank 6. The evaporator 4 of the refrigerator is installed directly on the heat storage tank 6, and ice is generated on its surface. The cold water in the heat storage tank 6 is circulated between the load 8 and the heat storage tank 6 by a pump 7.

The control method per day is shown in Figure 2. During the day, the refrigerator is usually turned off, but
When the water temperature in the heat storage tank exceeds the set value, cooling becomes impossible, so the refrigerator is operated. After the air conditioning is finished and at night, measure the water level in the heat storage tank using a float, etc., and calculate the amount of ice at that time using the following formula.

G _i =Σ _gi =Σ(V/H ₀ ×ΔH ₀ )/(1/ρ _i −1/ρ _w ) ……(1) where G _i : Amount of ice at the end of air conditioning (Kg) g _i : Amount of ice made at a certain time (Kg) V: Heat storage tank capacity (m ² ) H ₀ : Water depth (m) ΔH ₀ : Increase in water depth (m) ρ _i : Ice density (Kg/m ³ ) ρ _w : Density of water (Kg/m ³ ) Set the operation time of the refrigerator for ice making heat storage in proportion to the amount of ice determined here. The setting time is, for example, based on the following equation. T=-A(G _i /G ₀ ) ² +B Here, if the entire heat storage tank is ice, the refrigerator operating time is 0 hours, and if the entire heat storage tank is water, the refrigerator operating time is 10 hours. When set, T = -10 (G _i / G ₀ ) ² + 10 ... (2) where T: Operating time of the refrigerator for heat storage (Hour) G ₀ : Total amount of ice in the heat storage tank (Kg) G ₁ : Amount of ice at the end of air conditioning (Kg) Figure 3 shows the heat storage time setting device that implements this control method. In this device, the water level in the heat storage tank is detected by a water level detector 9 as a displacement of a float, etc., and the remaining amount of ice is calculated by an ice amount calculation circuit 10 according to equation (1). Furthermore, based on this signal, the heat storage time calculation circuit 11 calculates the heat storage time and sets it in the timer 12.

In fact, a comparison will be made between the conventional method of setting the operating time of a refrigerator at a constant rate every day and the present control method of cooling the air while setting the operating time for each day, using a medium-sized building as an example. If the cooling period is from July to September, the load will be as shown in Figures 4A to 4C. Fourth
Figure A shows the load in July, Figure 4B in August, and Figure 4C in September. Figure 5 shows the conventional method (the operating time of the refrigerator is 4 hours and 8 hours each day).
Figure 5B shows a comparison diagram of the cooling power due to heat storage and the power consumption of the new method. In FIG. 5B, the solid line shows the cooling power due to heat storage, and the broken line shows the total cooling capacity. When the refrigerator is operated for 8 hours, cooling is possible, but the power consumption is high, and when the refrigerator is operated for 4 hours, the power consumption is small, but cooling is not possible. In contrast, with the new method, although cooling is possible, the power consumption is small, and the cooling power from heat storage accounts for a large proportion of the total cooling capacity, so it can be said that cooling is performed efficiently. The new method can reduce power consumption by approximately 10% compared to the conventional method.

Although this invention has been applied to a direct expansion type in which the evaporator is installed directly in the heat storage tank, similar control can also be applied to a system in which ice is made via brine 13, as shown in FIG. I can do it.

〔Effect of the invention〕

As described above, according to the present invention, the refrigerator is operated at night when power consumption is low,
Furthermore, since the operating time of the chiller for anti-icing heat storage is set in proportion to the amount of ice at the end of air conditioning, there is no need to restart operating the chiller during the day, reducing power consumption. effective.

[Brief explanation of drawings]

Figure 1 is a block diagram of the night ice making heat storage system, Figure 2
The figure is a flowchart of the control method, Figure 3 is a diagram showing the method of setting the refrigerator operating time for ice making heat storage, and Figure 4A is a flow diagram of the control method.
Figures 4B and 4C are from July to September, respectively.
Figures 5A and 5B are diagrams of the load on the moon, and Figures 5A and 5B are comparison diagrams of the conventional method and the new method regarding power consumption and cooling power through heat storage, respectively. Figure 6 is the configuration of a system that makes ice through brine. It is a diagram. 1... Cooling tower, 2... Condenser, 3...
...Expansion valve, 4...Evaporator, 5...Compressor, 6...
Heat storage tank, 7...Pump, 8...Load, 9...Water level detector, 10...Ice amount calculation circuit, 11...Refrigerating machine operating time calculation circuit for ice making heat storage, 12...
...Timer, 13...Brine.

Claims (1)

[Claims] 1. In an ice making thermal storage system that consists of a refrigerator and a heat storage tank and uses nighttime electricity to store ice making heat, there is a means for detecting the amount of ice in the heat storage tank, and a means for ice making heat storage at night according to the amount of ice. What is claimed is: 1. A nighttime ice making heat storage system comprising a refrigerator control means for setting a refrigerator operating time.