JPS6256418B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a refrigeration system, more specifically, a refrigeration cycle system equipped with a single-stage compressor, which has a minimum set evaporation temperature and a high-temperature setting among a plurality of different set evaporation temperatures. The present invention relates to a refrigeration system in which the evaporation temperature and evaporation temperature can be simultaneously selected for each different evaporator.

Conventionally, this type of refrigeration apparatus has a series circuit of an expansion mechanism 20 and an evaporator 21 as shown in FIG.
2 and the series circuit of the evaporator 23,
A single refrigeration cycle system using different refrigerants is provided, and the decompression resistance of each expansion mechanism 20, 22 is set differently, and evaporation is performed at different set evaporation temperatures in the evaporators 21, 23, and high temperature side evaporation is performed. evaporator 2 of said series circuit with vessel 23;
3. A suction pressure regulating valve 24 is provided on the downstream side so that the outlet side pressure in each of the series circuits is made to match the output side pressure of the series circuit having the evaporator 21 that evaporates at the lowest set evaporation temperature. . and,
Evaporator 21 that evaporates at the lowest set evaporation temperature during operation
and a series circuit including an evaporator 23 that evaporates at a set evaporation temperature on the high temperature side,
The minimum set evaporation temperature and the high temperature set evaporation temperature can be obtained at the same time. In addition, 25 is a condenser.

However, using one type of refrigerant, a single-stage compressor 1
Even if an attempt is made to make it possible to set the set evaporation temperature over a wide range from the high temperature side to the low temperature side in a single refrigeration cycle system equipped with Both of them decrease, the accumulation coefficient decreases, and the refrigeration capacity decreases, so the setting range of the evaporation temperature is reduced to 1.
There was a problem in that it was not possible to set the evaporation temperature wider than the range that was compatible with the type of refrigerant used, and that the set evaporation temperature could not be set from the high temperature side to the desired ultra-low temperature.

The present invention was invented to solve the above problems, and its purpose is to have a single refrigeration cycle equipped with a single-stage compressor, to have a simple structure, and to be compact. However, it is possible to simultaneously select the lowest evaporation temperature and the higher temperature side evaporation temperature among multiple different set evaporation temperatures, and the setting range of both selection temperatures can be expanded over a wide range from the desired ultra-low temperature to high temperature. The aim is to provide efficient refrigeration equipment.

That is, the refrigeration system of the present invention is a refrigeration system in which a single refrigeration cycle system equipped with a single-stage compressor is filled with a plurality of types of refrigerants having different evaporation temperatures. The same number of condensers and evaporators are provided, and among the condensers, the high temperature side condenser is configured to exchange heat with an external cold source,
Further, a gas-liquid separator is provided between the condensers, the liquid region of the separator is connected to the cooling part of the low temperature side condenser via an expansion mechanism, and the gas region of the separator is connected to the cooling part of the low temperature side condenser. The liquid area of the separator is connected to the high temperature side evaporator via an expansion mechanism, and this connecting path a selection means for selecting communication or non-communication of the high-temperature side evaporator with the liquid region in the separator, and connecting the low-temperature side condenser to the low-temperature side evaporator via an expansion mechanism; , characterized in that the separator is provided with a storage section for storing surplus liquid refrigerant separated by the separator when the liquid refrigerant is not communicated with the high temperature side evaporator. be.

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

In the system shown in Figures 1 to 3, three types of first, second, and third refrigerants with different evaporation temperatures are mixed and filled in one refrigeration cycle system equipped with a single-stage compressor 1. It is something.

Specifically, the first, second, and third refrigerants have respective condensing temperatures at the same condensing pressure P 1 when the condensing pressure P ₁ and the evaporating pressure P ₂ are set based on an appropriate compression ratio of the compressor ₁ . T ₁ , T ₂ , and T ₃ are lower in that order (T ₁ > T ₂ > T ₃ ), and the same evaporation pressure
Each of the evaporation temperatures T ₄ , T ₅ , and T ₆ at P ₂ has a set value that is lower in that order (T ₄ >T ₅ >T ₆ ). When these three refrigerants are mixed within the temperature and pressure range of the refrigeration cycle system, refrigerants that do not cause chemical reactions with each other, do not substantially azeotrope, and are mutually soluble are selected. That's what I do. For example, the first refrigerant is Freon R12 (C Cl ₂ F ₂ ), the second refrigerant is Freon R13 (C Cl F 3 ), and the third refrigerant is Freon R14 (C Cl F ₃ ), and the third refrigerant is Freon R14 (C Cl F 3 ).
F ₄ ), respectively, for example, the set evaporation temperature T ₄ ,
T ₅ and T ₆ are evaporated at approximately 0°C, -60°C, and -110°C.

Further, the compressor 1 is equipped with a capacity control mechanism (not shown).

Therefore, three first, second, and third evaporators 2, 3, and 4, the same number as the number of refrigerants filled in the refrigeration cycle system, and first, second, and third condensers 5,
6 and 7 are provided, and the inlet of the first condenser 5 is connected to the discharge side of the compressor 1 to exchange heat with an external cold source 8 such as cooling water or the outside. A gas-liquid separator 9 is provided between the vessels 5 and 6, and
A gas-liquid separator 10 is provided between the second and third condensers 6 and 7, respectively. Then, the mixed refrigerant of the high-pressure gaseous first, second, and third refrigerants discharged from the compressor 1 is condensed in the first condenser 5 at the condensation temperature _T1 , and the gas-liquid Separator 9
Then, the refrigerant is separated from the gaseous first and second refrigerants.

The outlet of the first condenser 5 is connected to the inlet of the gas-liquid separator 9, and the liquid region of the gas-liquid separator 9 that stores the first refrigerant is connected to the common port of the three-way valve 11. , the switching port 11a of the three-way valve 11
The inlet of the cooling section 6a of the second condenser 6 is connected to the expansion mechanism 1.
2, and connect the outlet of the cooling section 6a to the compressor 1.
Connect to the suction side of the The three-way valve 11 keeps the switching port 11a with respect to the common port in a fully open or intermediately open state at all times without fully closing it, and the gas region of the second and third refrigerants of the gas-liquid separator 9 is condensed into the second condensation state. In the condenser 6, a cooling section 6a is connected to the condenser 6.
The first refrigerant on the high-temperature side passing through is used as a cold heat source to cool the second and third refrigerants on the low-temperature side, and the second refrigerant is condensed at the condensation temperature _T2 .

Further, the other switching port 11b of the three-way valve 11 connected to the liquid region of the gas-liquid separator 9 is connected to the expansion mechanism 1.
3 to the inlet of the first evaporator 2, and the outlet of the evaporator 2 to the cooling section 6a of the second condenser 6.
Connect to the entrance of The three-way valve 11 is
It constitutes a selection means for selecting communication or non-communication with the liquid region in the separator 9 of the first evaporator 2, and selectively connects the switching port 11b to the common port of the three-way valve 11. By controlling the fully closed or intermediately open state, the first evaporator 2 is selectively disconnected or communicated with the liquid region of the separator 9, so that the first evaporator 2 is not selected or selected. It will be accomplished. When the first evaporator 2 is selected, a predetermined flow rate of the first refrigerant is evaporated at the set evaporation temperature _T4 .

Further, the outlet of the second condenser 6 is connected to the inlet of the gas-liquid separator 10 to separate the liquid second refrigerant and the gaseous third refrigerant, and the second condenser 6 is separated from the gas-liquid third refrigerant. 2. The liquid area where the refrigerant is stored is connected to the three-way valve 14.
The switching port 14a of the three-way valve 14 is connected to the inlet of the cooling section 7a of the third condenser 7 via the expansion mechanism 15, and the outlet of the cooling section 7a is connected to the common port of the second condenser 6. It is connected to the inlet of the cooling section 6a. The three-way valve 14 always keeps the switching port 14a in a fully open or intermediately open state with respect to the common port without fully closing it. Further, the gas region of the third refrigerant of the gas-liquid separator 10 is connected to the third condenser 7, and in the condenser 7, the second refrigerant on the high temperature side passes through the cooling section 7a.
Cooling the third refrigerant on the low temperature side using the refrigerant as a cold heat source,
This is done as if it were condensed at a condensation temperature of _T3 .

Further, the other switching port 14b of the three-way valve 14 connected to the liquid region of the gas-liquid separator 10 is connected to the inlet of the second evaporator 3 via the expansion mechanism 16,
The outlet of the evaporator 3 is connected to the cooling section 7 of the third condenser 7.
Connect to the entrance of a. And the three-way valve 14
constitutes a selection means for selecting communication or non-communication of the second evaporator 3 with the liquid region in the separator 10, and selects the switching port 14b from the common port of the three-way valve 14. By controlling the second evaporator 3 to be fully closed or intermediately open, the second evaporator 3 is selectively disconnected or communicated with the liquid region of the separator 10, and the second evaporator 3 is controlled to be in a non-selective or intermediately open state. We do it because we choose it. When the second evaporator 3 is selected, a predetermined flow rate of the second refrigerant is supplied to the set evaporation temperature.
It is evaporated at _T5 .

Further, the outlet of the third condenser 7 is connected to the expansion mechanism 1.
7 to the inlet of the third evaporator 4, and the outlet of the evaporator 4 is connected to the inlet of the cooling section 7a of the third condenser 7. The refrigerant is evaporated at the evaporation temperature _T6 .

Each of the gas-liquid separators 9 and 10 has a capacity capable of storing an amount of refrigerant corresponding to each predetermined flow rate selected and distributed to the first and second evaporators 2 and 3 when not selected. Storage parts 9a and 10 are provided, and the storage part 9a stores liquid refrigerant separated by the separator 9, which is surplus when the liquid refrigerant is not communicated with the first evaporator 2. Further, in the storage section 10a, surplus liquid refrigerant, which is the liquid refrigerant separated by the separator 10 and is not communicated with the second evaporator 3, is stored.

Therefore, in the above configuration, when operating, in addition to the lowest evaporation temperature T 6 among the three set evaporation temperatures T ₄ , T ₅ , _{T 6} , the evaporation temperatures T ₄ , T ₅ on the high temperature side are set. First, the case where the highest evaporation temperature _T4 is selected will be explained. In this case, the three-way valve 1
1 to the switching ports 11a and 11 for the common port.
b are both held in an intermediately open state to select the first evaporator 2, and the three-way valve 14 is held in the common port with the switching port 14a fully open and the switching port 14b fully closed. 2 evaporator 3 is not selected.

Thus, by driving the compressor 1,
As shown by the arrows of solid lines, dotted lines, and chain lines (representing the first, second, and third refrigerants, respectively) in the Mollier diagrams of Fig. 1 and Fig. 4, the mixed gas refrigerant of the first, second, and third refrigerants has a discharge pressure of P ₁ The refrigerant is discharged (point A), flows into the first condenser 5, is cooled by an external cold source 8, and is condensed and liquefied only at a condensing pressure _{P1 and} a condensing temperature _T1 , and then in a gas-liquid separator 9. The first refrigerant, which is separated from the gaseous second and third refrigerants and stored (point B), flows into the three-way valve 11 together with a predetermined flow rate of refrigerant flowing into the first evaporator 2, and is connected to the switching port 11b, The former flows through the first evaporator 2 and is evaporated at a set evaporation temperature T4, and the former flows through the first evaporator ₂ and is evaporated at a set evaporation temperature _T4 . _T4 is obtained. Then, it flows out from the evaporator 2 and flows into the cooling section 6a of the second condenser 6 together with the latter reduced pressure liquid refrigerant. And the gas-liquid separator 9
The second gas flowing into the second condenser 6 from the gas region of
It is evaporated by the third refrigerant at an evaporation temperature T ₄ ,
It is sucked into the compressor 1 (point d).

On the other hand, the gaseous second and third refrigerants that have flowed into the second condenser 6 are cooled by the first refrigerant flowing through the cooling section 6a, and only the second refrigerant is condensed at a pressure P ₁ and a condensation temperature T ₂ . It is condensed, flows into the gas-liquid separator 10 together with the gaseous third refrigerant (point E), and is separated into gas and liquid.

Then, the second liquid stored in the liquid region of the gas-liquid separator 10
The refrigerant flows into the three-way valve 14, leaving an amount of second refrigerant corresponding to a predetermined flow rate flowing when selecting the second evaporator 3, which will be described later, in the storage portion 10a, flows into the three-way valve 14, flows out only from the switching port 14a, and flows into the expansion mechanism 15. It is reduced to pressure P ₂ (to point) and flows into the cooling section 7a of the third condenser 7. The second refrigerant that has flowed in this way is evaporated and vaporized at an evaporation temperature _T5 by the third refrigerant on the low temperature side that has flowed into the third condenser 7 from the gas region of the gas-liquid separator 10, and then is evaporated into the second condenser 6. It passes through the cooling section 6a and is sucked into the compressor 1 (point D).

Further, the gaseous third refrigerant that has flowed into the third condenser 7 is condensed at a condensing pressure P ₁ and a condensing temperature T ₃ (point T) by the second refrigerant flowing through the cooling section 7a, and the expansion mechanism 17 The pressure is reduced to P ₂ (point 1). Then, it flows into the third evaporator 4, where it is evaporated at the lowest set evaporation temperature _T6 , and then into the third and second condensers 7, 6.
The water is sucked into the compressor 1 through the cooling sections 7a and 6a (point d), and the lowest set evaporation temperature _T6 is obtained in the third evaporator 4.

Next, the three types of preset evaporation temperatures T ₄ , T ₅ ,
A case will be described in which the intermediate temperature _T5 is selected in addition to the lowest temperature _T6 among _T6 . In this case, the three-way valve 11 is connected to the switching port 11 to the common port.
a in a fully closed state and the switching port 11b in a fully closed state to de-select the first evaporator 2, and at the same time, the three-way valve 14 is connected to the common port into the switching port 1.
4a and 14b are both held in the intermediate open state, and the second
Evaporator 3 is selected.

Thus, by driving the compressor 1,
Refrigerants 1, 2, and 3 circulate as shown in Figure 2 (state changes are basically the same as in Figure 4, so omitted). The liquid first refrigerant separated into gas and liquid by the gas-liquid separator 9 flows into the three-way valve 11 and passes through the switching port 11.
When the first evaporator 2 is selected as described above, it flows only from the switching port 11b and does not flow from the switching port 11b.
The refrigerant is stored in the storage portion 9a of the gas-liquid separator 9 in an amount corresponding to the predetermined flow rate.

Further, the liquid second refrigerant separated into gas and liquid by the gas-liquid separator 10 flows into the three-way valve 14 together with a predetermined flow rate of refrigerant flowing into the second evaporator 3, and flows into the switching port 14.
It separates from a and 14b and flows out from the switching port 14.
The refrigerant that flows out from the switching port 11b is depressurized by the expansion mechanism 16, and is evaporated in the second evaporator 3 at the set evaporation temperature _T5 .

Furthermore, the three types of preset evaporation temperatures T ₄ , T ₅ ,
Among T ₆ , in addition to the minimum temperature T ₆ , the maximum and intermediate temperatures T ₄ ,
The case where both _T5 are selected will be explained. In this case, the three-way valves 11 and 14 have switching ports 11a, 11b, and 1 for the common port, respectively.
4a and 14b are held in the intermediate open state, and the second and third
Evaporators 3 and 4 are selected.

Thus, by driving the compressor 1,
The 1st, 2nd, and 3rd refrigerants circulate as shown in Figure 3 (state changes are basically the same as in Figure 4, so omitted), and the operation is different from that in Figures 1 and 2. The point is that the liquid first and second refrigerants separated by the gas-liquid separators 9 and 10, together with a predetermined flow rate of refrigerant flowing into the first and second evaporators 2 and 3, are separated by the three-way valves 11 and 14, respectively. Switching ports 11a, 11b, 1
4a and 14b, and the set evaporation temperature T ₄ described above is reached in the first and second evaporators 2 and 3.
Each is evaporated at T ₅ .

As described above, the gas-liquid separators 9, 10 are provided with the storage parts 9a, 10a, and the first and second evaporators 2, 3
The first and second flow rates correspond to the predetermined flow rate to be flowed when selecting the flow rate.
When the refrigerant is not selected in the first and second evaporators 2 and 3,
Since the storage parts 9a and 10a are configured to store water, when the three-way valves 11 and 14 are controlled to deselect the first and second evaporators 2 and 3, the gas-liquid separators 9 and 10
The first and second refrigerants are stored in the storage portions 9a and 10a in an amount corresponding to the predetermined flow rate, and when selected, the first and second refrigerant at the predetermined flow rate flow out from the storage portions 9a and 10a to 1, second evaporator 2, 3
will be distributed. Therefore, the liquid first and second refrigerants flow through the selected first and second evaporators 2 and 3 in just the right amount, ensuring that the set evaporation temperatures T ₄ and T ₅ described above are achieved. can.

In addition, the cooling parts 6a of the second and third condensers 6 and 7,
7a, during operation, the high temperature side reduced pressure liquid refrigerant of the first and second refrigerants is constantly passed through the gas-liquid separators 9 and 10.
Since the low-temperature side gas refrigerant of the second and third refrigerants flowing in from the gas region _of It will be done.

Moreover, the set evaporation temperatures T ₄ and T ₅ on the high temperature side and the set evaporation temperature T ₆ on the lowest temperature side are determined by selecting the first and second refrigerants and the third refrigerant. It can be set over a wide range from extremely high temperatures that would otherwise be impossible to achieve to extremely low temperatures.
Moreover, while using the compressor 1, the compression ratio can be set to an appropriate value without increasing the value, so the problems caused by increasing the compression ratio, namely, the volumetric efficiency and compression efficiency decrease, and the coefficient of performance decreases. At the same time, it is possible to eliminate the problem of reduction in refrigerating capacity.

In the above explanation, three types of refrigerants with different evaporation temperatures were used and the number of set evaporation temperatures was set to three, but using two or more types of refrigerants with different evaporation temperatures, It is also possible to set the number of set evaporation temperatures to two or four or more, and to select at least one of the remaining high-temperature temperatures in addition to the lowest temperature among the set evaporation temperatures.

As described above, the present invention provides a refrigeration system in which one refrigeration cycle system equipped with a single-stage compressor 1 is filled with a plurality of types of refrigerants having different evaporation temperatures. The same number of condensers 5, 7 and evaporators 2, 4 are provided, and among the condensers 5, 7, the high temperature side condenser 5 is configured to exchange heat with an external cold source; 5,7
A gas-liquid separator 9 is provided in between, and the liquid region of the separator 9 is transferred to the cooling section 7a of the low-temperature side condenser 7 by an expansion mechanism 12.
and the gas region of the separator 9 is connected to the low temperature side condenser 7 to condense the low temperature side refrigerant using the high temperature side refrigerant as a cold heat source. The liquid region is connected to the high temperature side evaporator 2 via the expansion mechanism 13, and this connection path is
Providing selection means for selecting communication or non-communication with the liquid region in the separator 9 of the high temperature side evaporator 2,
The low-temperature side condenser 7 is connected to the low-temperature side evaporator 4 via an expansion mechanism 17, and the liquid refrigerant separated by the separator 9 is supplied to the high-temperature side evaporator. 2 is provided with a storage section 9a for storing surplus liquid refrigerant when the liquid refrigerant is not communicated, so that reduced pressure liquid refrigerant always flows through the low temperature side evaporator 4, and the lowest set evaporation temperature can be obtained. , and the storage portions 9a and 10a of the separators 9 and 10 store the high temperature side refrigerant to be circulated when the high temperature side evaporators 2 and 3 are selected, and when the high temperature side evaporators 2 and 3 are selected, the stored refrigerant is circulated. At least one set temperature on the high temperature side can also be obtained at the same time.

Moreover, the set evaporation temperature on the high temperature side and the set evaporation temperature on the minimum temperature can be adjusted by selecting the high temperature side refrigerant and the low temperature side refrigerant. It can be set over a wide range of temperatures, even down to ultra-low temperatures. Moreover, while using compressor 1, the compression ratio can be set to an appropriate value without increasing it to a large value, so the problem caused by increasing the compression ratio is that the volumetric efficiency and compression efficiency decrease, resulting in a decrease in the coefficient of performance. At the same time, it is possible to eliminate the problem of reduced refrigeration capacity.

[Brief explanation of the drawing]

Figures 1 to 3 are refrigerant piping system diagrams showing an embodiment of the present invention. Figure 1 shows the case where the highest temperature is selected from two types of high-temperature set temperatures, and Figure 2 shows the case where the intermediate temperature is selected. In this case, FIG. 3 is a diagram showing the case where both the maximum temperature and the intermediate temperature are selected, FIG. 4 is a Mollier diagram, and FIG. 5 is an explanatory diagram showing a conventional example. 1... Compressor, 2... First evaporator, 3... Second evaporator, 4... Third evaporator, 5... First condenser, 6... Second
Condenser, 6a...Cooling section, 7...Third condenser, 7a...
Cooling section, 9, 10... Gas-liquid separator, 9a, 10a...
Reservoir, 12, 13, 15, 16, 17... expansion mechanism.

Claims (1)

[Claims] 1 A refrigeration system in which a single refrigeration cycle system equipped with a single-stage compressor 1 is filled with multiple types of refrigerants having different evaporation temperatures, the refrigeration system having the same number of condensers as the number of refrigerants filled in the refrigeration cycle system. 5, 7 and evaporator 2,
4, and among the condensers 5 and 7, the high temperature side condenser 5 is configured to exchange heat with an external cold source,
Further, a gas-liquid separator 9 is provided between the condensers 5 and 7, and the liquid region of the separator 9 is connected to the cooling section 7a of the low-temperature side condenser 7 via an expansion mechanism 12. The gas region of the separator 9 is connected to the low-temperature condenser 7 to condense the low-temperature refrigerant using the high-temperature refrigerant as a cooling heat source, while the liquid region of the separator 9 is is connected to the high-temperature side evaporator 2, and this connection path is provided with a selection means for selecting communication or non-communication of the high-temperature side evaporator 2 with the liquid region in the separator 9, and the low-temperature side condenser 7
is connected to the low-temperature side evaporator 4 via the expansion mechanism 17, and the liquid refrigerant separated by the separator 9 is not communicated with the high-temperature side evaporator 2. A refrigeration system characterized by being provided with a storage section 9a for storing surplus liquid refrigerant.