JPS6221888Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refrigeration system, and particularly to a refrigeration system in which a plurality of compressors and a plurality of evaporators are inserted into the same refrigerant circuit.

As shown in the system diagram of FIG. 1, a known refrigeration system of this type includes a compressor 1, a condenser 2, liquid line solenoid valves 3a and 3b, expansion valves 4a and 4b, a first evaporator 5a, and a second evaporator. 5b, evaporation pressure adjustment valve 6,
When the first evaporator 5a and the second evaporator 5b are used at different evaporation temperatures, the flow of refrigerant is from the compressor 1 to the condenser 2, as shown by the solid arrow. After that, the flow is divided into two parts, one of which flows from liquid line solenoid valve 3a → expansion valve 4a → first evaporator (for high temperature) 5a → evaporation pressure adjustment valve 6, and the other flows from liquid line solenoid valve 3b → Expansion valve 4b→
After flowing from the second evaporator (for low temperature) 5b to the check valve 7, both branched streams merge and return to the compressor 1.

Normally, the operating efficiency of a refrigeration system improves as the suction pressure of the compressor increases, and conversely decreases as the suction pressure decreases. The disadvantage is that the suction pressure of the compressor 1 is almost the same as the evaporation pressure of the second evaporator (for low temperature) 5b, and even though the first evaporator (for high temperature) 5a can normally operate efficiently. , the second evaporator (for low temperature) 5 with the evaporation pressure adjustment valve 6
This results in lowering the suction pressure to the same level as b, resulting in inefficient operation.

The present invention was proposed in view of these circumstances, and aims to improve the operating efficiency of a refrigeration system that has multiple evaporators used at different evaporation temperatures.
In a refrigeration system in which multiple compressors and multiple evaporators are inserted into the same refrigerant circuit, the purpose is to provide a refrigeration system that prevents product damage due to temperature rise in the event of compressor failure. The outlet side of the compressor is connected to the same number of connecting pipes as the plurality of compressors, and each of the connecting pipes is connected to the suction side of each of the compressors through a three-way valve, and the load on the evaporator is changed by switching the switching valve. The feature is that the compressor to be connected can be selected depending on the type of compressor.

An embodiment in which the present invention is applied to a refrigeration system having three compressors and two evaporators will be described with reference to the drawings. FIG. 2 is a system diagram thereof.

In the above figure, 11a, 11b, 11c are compressors, 12 is a condenser, 13a, 13b are liquid line solenoid valves, 14a, 14b are expansion valves, 15a
is the first evaporator (for high temperature), 15b is the second evaporator (for low temperature), and 18a, 18b, and 18c are each 3
It is a dialect.

To explain the flow of refrigerant in such a device, (1) First, when the load on the first evaporator (for high temperature) 15a is large and the load on the second evaporator (for low temperature) 15b is small, When the switching valves 18a, 18b are operated, the refrigerant from the compressors 11a, 11b, 11c is divided through the condenser 12, and one side passes through the liquid line solenoid valve 13a, the expansion valve 14a, and the first evaporator 15a. , and a three-way switching valve 18
a and the flow path of the compressor 11a and the three-way switching valve 18
After dividing the two parallel flow paths of b and compressor 11b, it flows to the condenser 12, and the other one flows to the liquid line solenoid valve 13b, expansion valve 14b, second evaporator 15b, 3
The condenser 1 via the switching valve 18c and the compressor 11c.
Flows in the order of 2 to perform the refrigeration cycle.

In this way, the refrigerant for two compressors 11a and 11b flows into the first evaporator 15a, and the refrigerant for one compressor 11c flows into the second evaporator 15b.

(2) Next, if the load on the first evaporator (for high temperature) 15a is small and the load on the second evaporator (for low temperature) 15b is large, operating only the three-way switching valve 18a will cause the compressor 11a to , 11b, 11c passes through the condenser 12 and is divided into two parts, one of which is the liquid line solenoid valve 13a, the expansion valve 14a, the first evaporator 15a, the three-way switching valve 18a, and the compressor 11.
a to the condenser 12, and the other side is a liquid line solenoid valve 13b, an expansion valve 14b, and a second evaporator 15b.
After passing through the three-way switching valve 18b and the compressor 11b, the refrigerant is divided into two parallel channels: one for the three-way switching valve 18b and the compressor 11c, and then flowing to the condenser 12 to perform a refrigerant cycle.

In this way, the compressor 11 is connected to the first evaporator 15a.
The refrigerant for one unit a flows, and the refrigerant for two compressors 11b and 11c flows to the second evaporator 15b.

(3) Furthermore, if one compressor, for example 11a, fails, when the three-way switching valve 18b is operated, the refrigerant is transferred to the first evaporator 15a and the three-way switching valve 18.
b, compressor 11b and second evaporator 15b, 3
Since the water flows to the condenser 12 after being separated through the two parallel flow paths of the switching valve 18c and the compressor 11c, the function of the evaporator will not stop due to a failure of the compressor.

Therefore, according to the present invention, the following effects can be achieved.

(1) In the conventional refrigeration system shown in Figure 1, troubles such as compressor failure can cause the temperature of the evaporator to rise and stored products to rot, which can cause major damage. In the equipment, 1 out of 3 compressors
If a unit breaks down, the evaporator function will not stop as mentioned in (3) above, and only 2 out of 3 units will malfunction.
Even if the stand breaks down, turn on the 3-way switching valve 18.
-By turning off, the evaporators 15a, 1
5b can be operated alternately to minimize damage to stored products.

(2) As mentioned earlier, in the conventional refrigeration system shown in Figure 1, the suction pressure is low and the efficiency is poor, but in this system, the evaporator and compressor are divided into groups using a three-way switching valve. Since the compressor used in connection with the first evaporator (for high temperature) 15a can be operated with a high suction pressure, efficiency is improved.

Incidentally, two compressors 11a and 11b are connected to the conventional refrigeration system shown in FIG. 1 and the first evaporator (for high temperature) 15a described in (1) above, and one
A comparison of the case where two compressors 11c are connected is as follows.

However, the operating conditions for a refrigeration system using R502 are as follows: Condensing temperature: +45℃ Evaporation temperature of the first evaporator: -10℃ Evaporation temperature of the second evaporator: -40℃ Degree of superheating, supercooling degree: 5° Enthalpy of discharge gas: id (kcal/Kg) Enthalpy of suction gas: is (kcal/Kg) Enthalpy of liquid refrigerant before expansion valve: i (kcal/Kg)
Kg) Calculate the performance coefficient using the formula below and compare.

Coefficient of performance η=is-i/id-is In the refrigeration system shown in Figure 1, η1=131.35-111.54/143.35-
131.35=19.81/12.00=1.651 In the device of the present invention; In the system of compressors 11a and 11b connected to the first evaporator 15a, η21=134.83−111.54/141.53−
134.83=23.29/6.70=3.476 In the system of compressor 11c connected to second evaporator 15b, η22=131.35−111.54/143.35−
131.35 = 19.81/12.00 = 1.651 In other words, for the entire device of the present invention, η2 = 1/3 (η ₂₁ × 2 × η ₂₂ ) = 1/3 (3.476 × 2 + 1.651) = 2.868 For comparison, η2/η1=2.868/1.651=1.737 That is, the device of the present invention can be operated with approximately 1.7 times the efficiency as compared to the conventional device shown in FIG.

In the above embodiment, an example of 3 compressors and 2 evaporators was shown, but there is no limit to the number of compressors and evaporators as long as there are 2 or more each. A solenoid valve may be used.

In short, according to the present invention, in a refrigeration system in which a plurality of compressors and a plurality of evaporators are inserted into the same refrigerant circuit, the outlet sides of the plurality of evaporators are connected to the same number of connecting pipes as the plurality of compressors. The connection pipes are connected to the suction side of each compressor through three-way valves, and the compressor to be connected can be selected according to the load on the evaporator by switching the switching valve. The present invention is extremely useful industrially because it provides a highly efficient refrigeration system.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing a known refrigeration system, and FIG. 2 is a system diagram showing an embodiment of the present invention. 11a, 11b, 11c...compressor, 12...
Condenser, 13a, 13b...liquid line solenoid valve, 1
4a, 14b...Expansion valve, 15a...First evaporator (for high temperature), 15b...Second evaporator (for low temperature), 1
8a, 18b, 18c...3-way switching valve.

Claims (1)

[Scope of utility model registration request] In a refrigeration system in which a plurality of compressors and a plurality of evaporators having different evaporation temperatures are inserted into the same refrigerant circuit, the outlet sides of the plurality of evaporators are connected by the same number of connecting pipes as the plurality of compressors, and the Each communication pipe is connected to the suction side of each of the compressors via a three-way valve, and by switching each of the three-way valves, it is possible to select the compressor to be connected according to the load of each of the evaporators. refrigeration equipment.