JPS61246558A - 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] a. Field of Industrial Application This invention relates to a refrigeration system, and in particular, a refrigeration circuit equipped with a plurality of evaporators connected in parallel to one compressor. This relates to refrigeration equipment.

b. Prior Art FIG. 3 is a refrigeration circuit diagram of a conventional refrigeration system, in which a gaseous refrigerant is converted into a high-pressure, high-temperature gas in the compressor 1. The compressor 1 is connected to a receiver tank 3 via a condenser 2 that changes the phase of a gaseous refrigerant into a liquid state. Evaporators 7 and 89 are connected to the receiver tank 3 that stores liquid refrigerant via expansion valves 4 and 5.6 that respectively reduce the pressure of the refrigerant. The evaporators 7, 8.9, which evaporate the refrigerant by absorbing heat of vaporization from the surroundings, are connected to the compressor 1 via a regulating valve 10.11, which adjusts the vapor pressure within the evaporator 7, 8.9. ing.

Conventional refrigeration equipment is configured as described above, and the state of the refrigerant at each location within the refrigeration equipment can be known from the Mollier diagram in Figure 4, where the vertical axis represents absolute pressure and the horizontal axis represents enthalpy. I can do it. The high-pressure, high-temperature gaseous refrigerant at the outlet side a of the compressor 1 undergoes a phase change to a high-pressure, normal-temperature liquid refrigerant at the outlet side of the receiver tank 3. This high-pressure, room-temperature liquid refrigerant flows through the expansion valves 4 and 5.
．． 6 outlet side, that is, the inlet side of evaporators 7, 8.9 c, d,
In e, it becomes a low-pressure, low-temperature refrigerant that has turned into wet vapor. Among the outlet sides c, d, and e, the pressure of the refrigerant on the outlet sides c and cl of the expansion valves 4 and 5 is higher than that on the outlet side C due to the action of the regulating valves 10 and 11, and the pressure on the outlet side C is higher than that on the outlet side d. It's also expensive. Evaporator 7
, 8.9, the refrigerant in a low-pressure, low-temperature state at the inlet sides c, d, and e of the evaporators 7, 8.9 absorbs heat of vaporization from the surroundings and increases its enthalpy. the exit side f,
In g and j, the refrigerant becomes a low-pressure, low-temperature gaseous refrigerant that has turned into superheated steam. The refrigerant on the outlet sides f and g of the evaporators 7 and 8 is supplied to the regulating valve 10.
11, the gas becomes a low-pressure, low-temperature gas at the same pressure as the outlet side of the regulating valve 10.11, and at the outlet side j of the evaporator 9, which is not connected to the regulating valve 10.11. and,
The refrigerant discharged from the regulating valves 10 and 11 and the refrigerant discharged from the evaporator 9 are mixed in gas at the inlet side of the compressor 1, and this mixed low-pressure, low-temperature gaseous refrigerant is sucked into the compressor 1. It can be done. Therefore, the refrigerant sucked into the compressor 1 is transferred to the evaporator 9, which has the lowest evaporation temperature among the evaporators 7 and 8.
In other words, since the pressure of the refrigerant on the outlet side j of the evaporator 9 is the lowest, the specific volume increases, the compression ratio increases, and the compression efficiency of the refrigeration system deteriorates.

C1 Problems to be Solved by the Invention As mentioned above, in the conventional refrigeration system, a gaseous refrigerant with a large specific volume is sucked into the compressor 1, which increases the compression ratio and deteriorates the compression efficiency. there were.

This invention was made to solve these problems, and aims to provide a refrigeration system with improved compression efficiency and a high coefficient of performance.

d. Means for Solving the Problems The refrigeration system according to the present invention has a high temperature evaporator at each outlet side g, j of the intermediate temperature and low temperature evaporators 8° and 9 other than the high temperature evaporator 7 having the highest evaporation temperature. Pressure pumps 12 and 13 are connected to pressurize the refrigerant up to the evaporation pressure of the vessel 7.

θ, Operation In the present invention, the refrigerant exiting from the intermediate temperature and low temperature evaporators 8.9 is sent to the pressurizing pump 12. The pressure is increased to the high temperature evaporator 7 which has the highest evaporation temperature, that is, the highest evaporation pressure, and the compressor 1 takes in high-pressure superheated steam.

f. Examples Examples of the present invention will now be described with reference to the drawings. FIG. 1 is a refrigeration circuit diagram of a refrigeration system showing an embodiment of the present invention, and the same or corresponding parts as in FIGS. 3 and 4 are given the same reference numerals, and the explanation thereof will be omitted. Among the evaporators 7.8.9, the intermediate temperature evaporator 8 excluding the outlet side f of the high temperature evaporator 7 having the highest evaporation temperature and the outlet sides g and j of the low temperature evaporator 9 having the lowest evaporation temperature are , pressure pumps 12.13 are connected. The pressurizing pump 12.15 pressurizes the refrigerant discharged from the intermediate temperature evaporator 8 and the low temperature evaporator 9 until it reaches the same pressure as the pressure at the outlet side f of the high temperature evaporator 7. These pressurized refrigerants are
The refrigerant discharged from the high-temperature evaporator 7 is mixed with the refrigerant at the inlet side n of the compressor 1, and is sucked into the compressor 1.

The state of the refrigerant at each location in the refrigeration system constructed as described above can be understood from the Mollier diagram shown in FIG. Compressor 1
The state changes of the refrigerant discharged from the outlet side 0 of the evaporators 7, 8, and 9 to the outlet sides f, g, and j of the evaporators 7, 8, and 9 are the same as in the conventional one shown in FIG. 4, and the explanation thereof is omitted. do. The refrigerant at the outlet side j of the low-temperature evaporator 9 is in a superheated vapor state, and this refrigerant is sucked into the pressurizing pump 13. The refrigerant is adiabatically compressed by the pressurizing pump 13 and pressurized along an isentropic line to the pressure of the refrigerant at the outlet side f of the high-temperature evaporator 7.

In this way, the pressure of the refrigerant on the outlet side m of the pressurizing pump 13 matches the pressure on the outlet side f of the high temperature evaporator 7. The refrigerant on the outlet side g of the intermediate temperature evaporator 8, which is in a superheated vapor state, is also adiabatically compressed by the pressurizing pump 12, and is pressurized to the pressure of the refrigerant on the outlet side f of the high temperature evaporator 7. The outlet side of the pressure pump 12! The refrigerant on the outlet side m of the pressurizing pump 13 has the same pressure as the refrigerant on the outlet side f of the high-temperature evaporator 7, and is also at a high pressure. 1 outlet side n
mixed in. Therefore, the specific volume of the refrigerant sucked into the compressor 1 is smaller than that of the conventional compressor 1, and the compression ratio is also reduced, improving the compression efficiency of the refrigeration system.

Next, as an example, the required compression power for the refrigeration system of the present invention and the conventional one will be calculated using refrigerant R-22. The temperature at the outlet of the condenser 2 of the present invention and the conventional one is 40°C. The temperature of the refrigerant at each point in the refrigeration system is 0°C at the inlet side C of the high-temperature evaporator 7, 5°C at the outlet side f, -20°C at the inlet side d of the intermediate-temperature evaporator 8, and -20°C at the outlet side g. Here, the temperature is -15°C, -40°C on the inlet side e of the low temperature evaporator 9, and -35°C on the outlet side j. At that time, the approximate enthalpy at each point indicated by each symbol in the Mollier diagrams of FIGS. 2 and 4 is 165.7 Kcal-AC9, f, h Teha 14
9.8KCal/KP, g? i Teha 147.8KC
a'/Kp, j Te is 145.7KCa1/9. Nite is 147.8 KCa'/Kg, 1-Tehi 5
2,0Kca1//, m Teha 155.0K
oaVKy, or: Ha159.6 KCa1/
It becomes Ky. Further, the amount of refrigerant circulated through each evaporator 7, 8.9 is assumed to be a and Ky/h, respectively.

Here, the compression required power N of the conventional refrigeration system.

When calculating, N, = 3- G(a-k)Kcal/h, = 53
．． 7 G Kcal/h.

Further, when calculating the required compression power N2 of the refrigeration system of this invention, N2=(m-j)・G+(J-g)・G+3・G(o-
n) = 55,40Kca.

As can be seen from the above calculation results, the required power N2 for the inventive system is less than the required power N1 for the conventional system, and the refrigeration system of the present invention has the same cooling capacity as the conventional system with a smaller required compression power than the conventional refrigeration equipment. It is possible to increase the value of the coefficient of performance ε (cooling capacity/required compression power) of the refrigeration system.

In the above embodiment, the case where there is one intermediate temperature evaporator (8) has been described, but it goes without saying that two or more intermediate temperature evaporators (8) may be used.

g3 Detailed Description of the Invention According to the present invention, the high temperature evaporator 7 is provided at the outlet sides g and j of the intermediate temperature and low temperature evaporators 8 and 9 other than the high temperature evaporator 7 having the highest evaporation temperature. By connecting the pressurizing pumps 12 and 13 that pressurize the refrigerant to the evaporation pressure, the specific volume of the refrigerant sucked into the compressor 1 becomes smaller.
This has the effect of improving the compression efficiency of the refrigeration equipment and increasing the coefficient of performance.

[Brief explanation of drawings]

Fig. 1 is a refrigeration circuit diagram of the refrigeration system of the present invention, Fig. 2 is a Mollier diagram of the one shown in Fig. 1, Fig. 3 is a refrigeration circuit diagram of a conventional refrigeration system, and Fig. 4 is a Mollier diagram of the one shown in Fig. 6. It is a line diagram. 1. Compressor, 7. High temperature evaporator, 8. Intermediate temperature evaporator, 9. Low temperature evaporator, 12.13. Pressure pump. Patent applicant: Hoshizaki Electric Co., Ltd. Figure 1, Figure 2

Claims (1)

[Claims] For one compressor (1), a high temperature evaporator (7) with the highest evaporation temperature and a low temperature evaporator (9) with the lowest evaporation temperature
and one or more intermediate-temperature evaporators (8) having evaporation temperatures between them, each of which is connected in parallel and incorporated therein, the low-temperature evaporator (9) and A pressurizing pump (13, 12) for pressurizing the refrigerant up to the evaporation pressure of the high-temperature evaporator (7) is connected to each outlet side (j, g) of the intermediate-temperature evaporator (8). Refrigeration equipment.