JPS5849866A - 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 refrigeration system suitable for refrigerator-freezers, refrigeration units, sea cases, two-temperature freezers, two-temperature refrigerators, and the like.

The refrigeration cycle of a conventional refrigerator-freezer is shown in FIG. In the figure, 1 is a compressor, 2 is a condenser, 3 is a pressure reduction mechanism, 4 is an evaporator, 5 is a freezer compartment, and 6 is a refrigerator compartment. Supplied to the refrigerator room. In the refrigerator compartment, the air inside the refrigerator compartment and the air supplied from the freezer compartment are mixed to obtain the required room temperature. When the refrigeration cycle in this case is represented by a Mollier diagram, it becomes K as shown in FIG. The coefficient of performance on the diagram of this refrigeration cycle (
cop) is expressed by equation (1).

Here, Δie: difference in refrigerant enthalpy at the entrance and exit of the evaporator Δio: refrigerant enthalpy at the entrance and exit of the compressor temperature cannot be lowered to the desired value.

Next, a refrigerator K (with an internal temperature of about 5° C.) will be explained. Since the temperature inside the refrigerator is around 5°C, it is necessary to keep the refrigerant temperature in the evaporator below 0°C. Therefore, frost forms on the surface of the evaporator and performance deteriorates over time, so it is necessary to melt the frost when the amount of frost becomes large. Reducing the rate of frost formation slows down the rate of performance deterioration and increases energy savings. Furthermore, the temperature inside the refrigerator often rises due to the heat generated when one frost is melted, which causes fluctuations in the temperature of the items stored in the refrigerator and causes a drop in quality. FIG. 3 shows the configuration of a conventional dual evaporation temperature type refrigeration cycle corresponding to the two examples of the refrigerator-freezer and refrigerator described above.

In FIG. 2, the refrigerant discharged from the compressor 11 and liquefied in the condenser 22 is divided into two systems. Decompression mechanisms 13 and 14
The evaporator 15 has different flow path resistance values, and the suction force from the middle part of the compressor 11 (in this figure, the gas cylinder type is explained) and the suction force from the low pressure are selected. The amount of refrigerant flowing through and 16 and the pressure of the two evaporators can be adjusted. Each evaporator (the evaporated refrigerant is made high pressure by the compressor 11 and then sent to the condenser 1 again)
Sent to 2. When the behavior of this refrigerant is expressed in a Mollier diagram, it becomes K as shown in FIG. The refrigerant flowing at intermediate pressure is only energized by Δ'CM in the compressor, and the cooling capacity is ΔieM. Regarding the refrigerant flowing on the low pressure side, the pressure-power is Δ'CL and the cooling capacity is Δ8e. Therefore, if the amount of refrigerant flowing through the evaporator 15 is ql and the amount of refrigerant flowing through the evaporator 16 is GL, the CO on the diagram of this cycle is
P is as shown in equation (2).

When GM is zero, the COP in equation (1) is equal to G, and as G becomes larger, the COP shown in equation (2) becomes larger.

Now, the air passing through the evaporator 15 is transferred to the refrigerator compartment, and the air passing through the evaporator 16 is
If the air passing through is supplied to the freezer compartment, it can be applied to the freezer/refrigerator cycle. Also, the refrigerant temperature in the evaporator 15 is set to 0°C -
After that, the temperature of the evaporator 16 is kept below 0°C, and the air flow is first cooled by passing 15 tC through the evaporator, and the water vapor in the air is removed in the form of water, and then the air is passed through the evaporator. 16, the absolute humidity in the air is low, so the amount of frost formation can be reduced and the desired temperature in the refrigerator room can be achieved. This can be applied to refrigerator cycles with longer defrost cycles.

However, these cycle COPs are not sufficient to meet current social needs. Furthermore, the present invention, which requires a refrigeration cycle with a high KCOP, was invented in view of the above. - The purpose is to further improve energy saving and lengthen the defrosting cycle.

In order to achieve the above object, the present invention includes two evaporators with different evaporation temperature levels, two condensers, two pressure reduction mechanisms, and a gas-liquid separator. Gas and liquid are separated in a liquid separator, and a part of the liquid and gas are appropriately mixed and supplied to the evaporator to obtain an intermediate temperature cooling effect, and the remaining liquid is further transferred to the second stage by another pressure reducing mechanism. It has the characteristic of being expanded and supplied to other evaporators to obtain a low-temperature cooling effect.

Embodiments of the present invention will be described below with reference to the drawings.

5 and 1716 are refrigeration cycle system diagrams showing embodiments of the present invention, respectively. In the figure, 21 is an engine type compressor, 21''' is a main compressor, 21b is an auxiliary compressor, 22 is a condenser, 23.24 is a pressure reducing mechanism, and 25.26
2T is an evaporator, 2T is a gas-liquid separator, and the above-mentioned devices are connected by piping as shown in the figure to form respective refrigeration cycles.

An ejector as shown in FIG. 1 can be considered as an example for appropriately adjusting the gas-liquid mixture ratio of the refrigerant flowing from the gas-liquid separator 27 to the evaporator 25. However, using a different method does not change the fundamental characteristics of the cycle.

The refrigeration cycles shown in FIGS. 5 and 6 are represented in a Mollier diagram as shown in FIG. 8.

The energy saving performance of the refrigeration cycle shown in FIG. 5 and IllES diagram of this embodiment and the conventional refrigeration cycle shown in FIG. 3 and III will be compared with reference to the Mollier diagram. -9
The figure shows a Mollier diagram when the intermediate pressure is set to Jii 7 - with respect to the discharge pressure Pd and the low pressure P in the conventional cycle shown in FIG. 3.

The coefficient of performance of the conventional Mollier diagram #E2 and FIG. 9 and the Mollier diagram of this embodiment shown in FIG. 8 can be obtained by the following formula. The intermediate pressure is calculated as the discharge pressure Pd in the COP of Fig. 8.

Here, the COP competition ζ in Fig. 9 is expressed as follows: C: Reciprocal of compressor efficiency when compressing from intermediate pressure to discharge pressure, m: Reciprocal of compressor efficiency when compressing from low pressure to discharge pressure: Enthalpy (subscript g: saturated gas, l: saturated liquid) G: refrigerant flow rate (subscript M: intermediate pressure side, L: low pressure II) Now, let's specifically determine the energy saving effect.

Conditions n = 5 Tortoise = 1.4 Refrigerant R-22
, discharge pressure 17 ata.

Intermediate pressure 5 ata, low pressure 1.5 atas = 1
101d119, it becomes as shown in the table below.

That is, the cycle of the present invention has a very large energy saving effect.

As explained above, according to the present invention, the coefficient of performance is greatly improved compared to conventional refrigeration equipment, and energy saving performance can be improved.

[Brief explanation of the drawing]

Figure 1 is a cycle diagram of a conventional refrigeration system, Figure 2 is a Mollier diagram of the system shown in Figure 1, Figure 3 is a cycle diagram of another conventional refrigeration system, and Figure 4 is a cycle diagram of the system shown in Figure 3. A general Mollier diagram is shown. FIG. 5 is a cycle diagram of a refrigeration system showing one embodiment of the present invention. FIG. 6 is a cycle diagram of a refrigeration system showing another embodiment, and FIG. 7 shows an example of a gas-liquid separator. FIG. 8 shows a sorrel diagram of the cycles of the apparatuses shown in FIGS. 5 and 6, and FIG. 9 shows a comparative Mollier diagram of the conventional cycle shown in FIG. 3. 21.21a, 21b... Compressor 22... Condenser 23.24... Pressure reduction mechanism 25.26... Evaporator 2
7... Gas-liquid separator bm,, f Country of arrival

Claims (1)

[Claims] Equipped with two evaporators with different evaporation temperature levels, a compressor or two compressors capable of gas in-seeking, two condensers, two pressure reduction mechanisms and a gas-liquid separator, and the pressure reduction mechanism allows general expansion. The refrigerant is separated into gas and liquid using a gas-liquid separator, and a part of the liquid and gas are appropriately mixed and supplied to the evaporator to obtain air or brine at an intermediate temperature, and the remaining liquid is removed using another pressure reducing mechanism. A refrigeration system characterized by further expanding the second stage and supplying it to another evaporator to obtain low-temperature air or brine.