JP6495053B2 - Refrigeration system, refrigeration system operation method, and refrigeration system design method - Google Patents

Description

  The present invention relates to a refrigeration system, a refrigeration system operation method, and a refrigeration system design method.

  A refrigerator with a refrigeration cycle has a refrigerating capacity determined by the capacity of a compressor, a condenser, an expansion valve, an evaporator, and the like. When determining the refrigerating capacity (equipment capacity) of a refrigerator, the capacity of a compressor, a condenser, an expansion valve, an evaporator, and the like is generally set so as to satisfy the heat demand of a cooling target.

  In Patent Document 1 below, it is possible to reduce the temperature of cooling water supplied to a condenser or the like when peak power is generated during the daytime, etc., and to improve the power generation efficiency. A technique for storing cold energy in the form of a cold medium using thermal energy is disclosed.

JP 2000-64813 A

  The maximum value of the heat load used for determining the refrigerating capacity of the refrigerator is a value at the start of cooling until the object to be cooled is changed from the state before cooling to the cooled state. That is, the maximum value of the heat load is a value obtained by adding the heat capacity to be cooled to the heat load during the cooling operation. Therefore, in the steady state where the object to be cooled is cooled, it is sufficient if there is a refrigeration capacity for the heat load of the object to be cooled, so the capacity of the refrigerator is excessive.

  Moreover, the compressor, the condenser, the expansion valve, and the evaporator, which are the components of the refrigerator, are difficult to cope with the rapidly changing demand and supply matching, and cannot cope with the rapid start-up.

  This invention is made | formed in view of such a situation, Comprising: The freezing system which can reduce the capacity | capacitance of the compressor which supplies the compressed refrigerant | coolant to a condenser, the operating method of a freezing system, and a freezing system The purpose is to provide a design method.

In order to solve the above problems, the refrigeration system, the refrigeration system operating method, and the refrigeration system design method of the present invention employ the following means.
That is, in the refrigeration system according to the reference example of the present invention , the first storage unit that temporarily stores the refrigerant, the first compressor that compresses the refrigerant, and the refrigerant stored in the first storage unit are the first storage unit. A condenser to be condensed together with the refrigerant compressed by the compressor, a first expansion part for expanding the refrigerant condensed by the condenser, and heat exchange with the object to be cooled, and evaporating the refrigerant expanded in the first expansion part An evaporator, and the first storage unit stores the refrigerant evaporated in the evaporator or the refrigerant stored in the first storage unit in accordance with the heat load to be cooled. To supply.

  According to this configuration, for example, when the heat load to be cooled is low, the refrigerant is stored in the first storage unit, and when the heat load to be cooled is high, the stored refrigerant is supplied to the condenser. That is, when the heat load to be cooled is high, the refrigerant stored in the first storage unit is used. Therefore, the 1st compressor of a refrigerating system can be made small compared with the case where the refrigerant stored by the 1st storage part is not used.

In the above reference example , the first storage unit stores the refrigerant compressed by the first compressor after being evaporated by the evaporator according to the heat load to be cooled.

  According to this configuration, the circulation of the refrigerant to the condenser side and the storage of the refrigerant in the first storage unit are performed by the first compression unit.

In the refrigeration system according to the present invention, a first storage unit that temporarily stores a refrigerant, a first compressor that compresses the refrigerant, and a refrigerant stored in the first storage unit are compressed by the first compressor. A condenser for condensing together with the refrigerant, a first expansion section for expanding the refrigerant condensed in the condenser, an evaporator for exchanging heat with the object to be cooled and evaporating the refrigerant expanded in the first expansion section, A second compressor that compresses the refrigerant evaporated in the evaporator and stores the refrigerant in the first storage unit, and the first storage unit evaporates in the evaporator according to a heat load of the cooling target. Then, the refrigerant compressed by the second compressor is stored, or the refrigerant stored in the first storage unit is supplied to the condenser .

  According to this structure, when storing a refrigerant | coolant in a 1st storage part, not a 1st compressor but a 2nd compressor can be used, and the capacity | capacitance of a 1st compressor can be reduced.

The above invention further includes a second storage part that temporarily stores the refrigerant, wherein the second storage part stores the refrigerant expanded in the first expansion part, and stores the refrigerant stored in the second storage part. The refrigerant is supplied to the evaporator, the refrigerant evaporated in the evaporator is stored, and the refrigerant stored in the second storage unit is supplied to the first compressor.

According to this configuration, since the refrigerant can be stored in the second storage section and the stored refrigerant can be supplied to the evaporator and the first compressor, the stored refrigerant is used according to the fluctuation of the heat load to be cooled. Or the refrigerant can be stored in the second storage part. Moreover, it can respond when the thermal load to be cooled becomes excessively more rapidly than during steady operation, and can be started in a shorter time than when there is no stored refrigerant, that is, it can be started quickly.

  The said invention WHEREIN: The 2nd expansion part which expands the refrigerant | coolant evaporated with the said evaporator and supplies the expanded refrigerant | coolant to a said 2nd storage part is further provided.

  According to this configuration, the refrigerant that has passed through the second expansion part is flushed and adiabatically expanded by the second expansion part. As a result, the temperature of the second reservoir can be reduced.

  In the above invention, the first expansion section is an expansion turbine, and a rotation shaft of the expansion turbine is connected to a rotation shaft of a generator.

  According to this structure, when a refrigerant | coolant passes an expansion turbine, the rotating shaft of an expansion turbine rotates and a generator produces electric power with the rotational force.

The operating method of the refrigeration system according to the present invention includes a first storage unit that temporarily stores a refrigerant, a first compressor that compresses the refrigerant, and a refrigerant stored in the first storage unit. A condenser that condenses together with the refrigerant compressed in step 1, a first expansion part that expands the refrigerant condensed in the condenser, and an evaporator that exchanges heat with the object to be cooled and evaporates the refrigerant expanded in the first expansion part And a second compressor that compresses the refrigerant evaporated in the evaporator and stores the refrigerant in the first storage unit , according to the heat load of the cooling target, The refrigerant evaporated in the evaporator and compressed in the second compressor is stored in the first storage part, and the refrigerant stored in the first storage part is condensed according to the heat load to be cooled. Supplying to the vessel.

The design method of the refrigeration system according to the present invention includes a first storage unit that temporarily stores a refrigerant, a first compressor that compresses the refrigerant, and a refrigerant stored in the first storage unit. A condenser that condenses together with the refrigerant compressed in step 1, a first expansion part that expands the refrigerant condensed in the condenser, and an evaporator that exchanges heat with the object to be cooled and evaporates the refrigerant expanded in the first expansion part And a second compressor that compresses the refrigerant evaporated in the evaporator and stores the refrigerant in the first storage unit, and the first storage unit evaporates in accordance with the heat load of the cooling target. A method for designing a refrigeration system that stores refrigerant that has been evaporated in a condenser and compressed in the second compressor, or that supplies refrigerant stored in the first storage unit to the condenser , A step of acquiring a fluctuation of the thermal load and a fluctuation of the acquired thermal load; Based on, and determining the volume of the first reservoir.

  According to this configuration, the refrigerant is stored in the first storage unit during a period when the thermal load of the cooling target is low, and all the stored refrigerant is supplied to the condenser during the period when the thermal load of the cooling target is high. The capacity of the first reservoir can be determined. As a result, the capacity of the first compressor, the condenser, and the first expansion unit of the refrigeration system can be reduced, and the first storage unit can also have an appropriate capacity.

  ADVANTAGE OF THE INVENTION According to this invention, the capacity | capacitance of the compressor which supplies the compressed refrigerant | coolant to a condenser can be reduced.

It is a lineblock diagram showing the refrigerating system concerning a reference embodiment of the present invention. It is a graph which shows the relationship between the heat load and time in the refrigerating system which concerns on reference embodiment of this invention. 1 is a configuration diagram illustrating a refrigeration system according to a first embodiment of the present invention.

Embodiments according to the present invention will be described below with reference to the drawings.
[ Reference embodiment]
The refrigeration system 1 according to the reference embodiment of the present invention is applied to, for example, an air conditioner, a refrigeration apparatus, and the like.

  As shown in FIG. 1, the refrigeration system 1 according to this embodiment includes a compressor 3, a condenser 5, an expansion valve 6, an evaporator 7, and a first tank 8. The compressor 3, the condenser 5, the expansion valve 6, and the evaporator 7 are connected by piping, and a refrigeration cycle is comprised. The refrigerant circulating through the refrigeration cycle is, for example, nitrogen.

  The compressor 3 is driven by, for example, the electric motor 4, compresses and liquefies the refrigerant to be sucked, and discharges the compressed refrigerant. The discharge side of the compressor 3 is connected to each of the condenser 5 and the first tank 8 by pipes L1 and L2. The refrigerant compressed by the compressor 3 is supplied to the condenser 5. In addition, the refrigerant compressed by the compressor 3 is supplied to the first tank 8 in addition to the condenser 5 at the time of low load.

The condenser 5 cools the refrigerant with, for example, cooling water, and condenses the refrigerant. The cooling water that exchanges heat with the refrigerant circulates in a cooling water circulation circuit having a cooling water pump 21 and a cooler 22 using water outside the refrigeration system 1 as a cooling heat source. The cooler 22 in the cooling water circulation circuit cools the cooling water in the cooling water circulation circuit with water outside the refrigeration system 1 supplied by the cooling water pump 23. Refrigerant is supplied to the condenser 5 from the compressor 3. In addition, when the heat load to be cooled is high, that is, when the load is high, the refrigerant is supplied to the condenser 5 from the first tank 8 in addition to the compressor 3.
The refrigerant condensed in the condenser 5 is supplied to the expansion valve 6.

  The expansion valve 6 expands the refrigerant condensed in the condenser 5. The refrigerant expanded by the expansion valve 6 is supplied to the evaporator 7. A precooler 9 may be provided between the condenser 5 and the expansion valve 6. In the precooler 9, the refrigerant condensed in the condenser 5 and the refrigerant evaporated in the evaporator 7 exchange heat, and the refrigerant evaporated in the evaporator 7 is cooled before being sucked into the compressor 3.

  The evaporator 7 is located on the load side to be cooled and exchanges heat with the cooling target. The evaporator 7 evaporates the refrigerant expanded by the expansion valve 6. The refrigerant evaporated in the evaporator 7 is supplied to the compressor 3. In addition, during high load, the refrigerant evaporated by the evaporator 7 and passing through the precooler 9 is supplied to the first tank 8 in addition to the compressor 3.

  In the first tank 8, the refrigerant is temporarily stored. The first tank 8 is connected to a pipe L4 branched from the pipe L3 connected to the suction side of the compressor 3, and is connected to a pipe L2 joined to the discharge side pipe L1 of the compressor 3.

  When the heat load to be cooled is low, that is, when the load is low, the refrigerant liquefied by the compressor 3 is stored in the first tank 8 from the discharge side of the compressor 3 via the pipes L1 and L2. At this time, the refrigerant gas in the first tank 8 is supplied from the first tank 8 to the suction side of the compressor 3 via the pipes L4 and L3.

  Further, when the heat load to be cooled is high, that is, when the load is high, the refrigerant stored in the first tank 8 is supplied to the condenser 5 via the pipe L1. At this time, the refrigerant evaporated in the evaporator 7 is also supplied to the first tank 8 via the pipes L3 and L4 while being supplied to the suction side of the compressor 3 via the pipe L3.

Next, with reference to FIG. 2, operation | movement of the refrigerating system 1 which concerns on this embodiment is demonstrated.
First, before the object to be cooled is cooled by the refrigeration system 1, the refrigerant compressed by the compressor 3 is stored in the first tank 8.

After storage of the refrigerant in the first tank 8 is completed, a cooling target is prepared on the load side, and cooling of the cooling target is started.
At this time, the refrigerant gas is taken out from the first tank 8 through the pipe L2, and the refrigerant gas taken out from the first tank 8 is combined with the refrigerant gas supplied from the compressor 3 through the pipe L1 to the condenser 5. Supplied to.

  Thereby, the amount of refrigerant circulating through the refrigerant circuit increases, and the refrigeration capacity of the refrigeration system 1 is enhanced. At this time, a part of the refrigerant gas supplied from the load side to the compressor 3 side is supplied to the first tank 8 via the pipes L3 and L4.

  By continuing the cooling on the load side while taking out the refrigerant gas from the first tank 8, the thermal load to be cooled decreases.

Then, when the heat load becomes lower than the installed capacity of the refrigerant system, the extraction of the refrigerant gas from the first tank 8 is stopped, and the refrigerant compressed by the compressor 3 via the pipes L1, L2 is removed from the first tank. 8 is stored. At this time, the refrigerant gas in the first tank 8 is supplied from the first tank 8 to the compressor 3 via the pipe L4.
By storing the compressed refrigerant in the first tank 8, it can be provided when the load side becomes a high load.

  When the operation of the refrigeration system 1 is stopped and the heat load becomes higher than the facility capacity of the refrigerant system, the storage of the compressed refrigerant in the first tank 8 is stopped. Thereafter, similarly to the above, the extraction of the refrigerant gas from the first tank 8 is started.

First Embodiment
The refrigeration system 2 according to this embodiment includes a compressor 3, a condenser 5, an expansion valve 6, an evaporator 7, a recovery compressor 10, a first tank 8, a second tank 12, and an expansion valve. 13 is provided. The compressor 3, the condenser 5, the expansion valve 6, and the evaporator 7 are connected by piping, and a refrigeration cycle is comprised. The refrigerant circulating through the refrigeration cycle is, for example, nitrogen.

The compressor 3 is driven by, for example, the electric motor 4, compresses the refrigerant to be sucked, and discharges the compressed refrigerant. The refrigerant compressed by the compressor 3 is supplied to the condenser 5 via the pipe L1.
The condenser 5 cools the refrigerant with, for example, cooling water, and condenses the refrigerant. The cooling water that exchanges heat with the refrigerant circulates in a cooling water circulation circuit having a cooling water pump 21 and a cooler 22 using water outside the refrigeration system 2 as a cooling heat source. The cooler 22 of the circulating circuit for cooling water cools the cooling water of the circulating circuit for cooling water with water outside the refrigeration system 2 supplied by the cooling water pump 23. Refrigerant is supplied to the condenser 5 from the compressor 3. In addition, when the heat load to be cooled is high, that is, when the load is high, the refrigerant is supplied to the condenser 5 from the first tank 8 in addition to the compressor 3.
The refrigerant condensed in the condenser 5 is supplied to the expansion valve 6.

  The expansion valve 6 expands the refrigerant condensed in the condenser 5. The refrigerant expanded by the expansion valve 6 is supplied to the second tank 12 and then supplied to the evaporator 7 by the supply pump 24. A precooler 9 may be provided between the condenser 5 and the expansion valve 6. In the precooler 9, the refrigerant condensed in the condenser 5 and the refrigerant evaporated in the evaporator 7 exchange heat, and the refrigerant evaporated in the evaporator 7 is cooled before being sucked into the compressor 3.

  The evaporator 7 is located on the load side to be cooled and exchanges heat with the cooling target. The evaporator 7 is expanded by the expansion valve 6 and evaporates the refrigerant stored in the second tank 12. The refrigerant evaporated in the evaporator 7 is supplied to the second tank 12 and then supplied to the compressor 3. The refrigerant evaporated in the evaporator 7 is also supplied to the first tank 8 through the recovery compressor 10 in addition to the compressor 3.

  The recovery compressor 10 is driven by, for example, an electric motor 11, compresses the refrigerant to be sucked, and discharges the compressed refrigerant. The recovery compressor 10 is branched from a pipe L <b> 3 connecting the precooler 9 and the compressor 3, and is provided in a pipe L <b> 4 connected to the first tank 8. The refrigerant supplied from the evaporator 7 and compressed by the recovery compressor 10 is supplied to the first tank 8.

  In the first tank 8, the refrigerant is temporarily stored. The first tank 8 is connected to a pipe L4 branched from the suction side pipe L3 of the compressor 3, and is connected to a pipe L2 joined to the discharge side pipe L1 of the compressor 3.

  When the heat load to be cooled is low, that is, when the load is low, the refrigerant compressed by the recovery compressor 10 is stored in the first tank 8 from the discharge side of the recovery compressor 10 via the pipe L4. At this time, the refrigerant gas in the first tank 8 is supplied from the first tank 8 to the discharge side of the compressor 3 via the pipe L2.

  Further, when the heat load to be cooled is high, that is, when the load is high, the refrigerant stored in the first tank 8 is supplied to the condenser 5 via the pipes L2 and L1. At this time, the refrigerant evaporated in the evaporator 7 is supplied to the suction side of the compressor 3 through the pipe L3, passes through the recovery compressor 10 through the pipes L3 and L4, and also enters the first tank 8. Supplied.

  The second tank 12 temporarily stores the refrigerant. The wall portion of the second tank 12 is, for example, vacuum-insulated to reduce heat conduction. The second tank 12 includes piping connected to the outlet side of the expansion valve 6, piping connected to the inlet side of the evaporator 7, piping connected to the outlet side of the evaporator 7, and suction of the compressor 3. Connected to piping connected to the side.

  The second tank 12 stores the refrigerant expanded by the expansion valve 6 and supplies the refrigerant stored in the second tank 12 to the evaporator 7. Further, the refrigerant evaporated in the evaporator 7 is stored, and the refrigerant stored in the second tank 12 is supplied to the compressor 3.

  An expansion valve 13 is installed in a pipe connecting the outlet side of the evaporator 7 and the second tank 12. The expansion valve 13 expands the refrigerant supplied from the evaporator 7. Thereby, a refrigerant | coolant adiabatically expands and the temperature in the 2nd tank 12 can be reduced.

Next, the operation of the refrigeration system 2 according to this embodiment will be described.
First, before the object to be cooled is cooled by the refrigeration system 2, the refrigerant is stored in the first tank 8 compressed by the recovery compressor 10.

After storage of the refrigerant in the first tank 8 is completed, a cooling target is prepared on the load side, and cooling of the cooling target is started.
At this time, the refrigerant gas is taken out from the first tank 8 through the pipe L2, and the refrigerant gas taken out from the first tank 8 is combined with the refrigerant gas supplied from the compressor 3 through the pipe L1 to the condenser 5. Supplied to.

  Thereby, the amount of refrigerant circulating through the refrigerant circuit is increased, and the refrigeration capacity of the refrigeration system 2 is enhanced. In addition, while the capacity of the compressor 3 is reduced, the amount of refrigerant circulating in the refrigeration system 2 can be increased and the refrigeration capacity can be improved. At this time, a part of the refrigerant gas supplied from the load side to the compressor 3 side is branched via the pipes L3 and L4 and supplied to the first tank 8.

  By continuing the cooling on the load side while taking out the refrigerant gas from the first tank 8, the thermal load to be cooled decreases.

When the heat load becomes lower than the installed capacity of the refrigerant system, the extraction of the refrigerant gas from the first tank 8 is stopped, and the refrigerant compressed by the recovery compressor 10 is supplied to the first tank via the pipe L4. 8 is stored.
By storing the liquefied refrigerant in the first tank 8, it can be prepared when the load side becomes a high load.

  When the operation of the refrigeration system 2 is stopped and the heat load becomes higher than the facility capacity of the refrigerant system, the storage of the compressed refrigerant in the first tank 8 is stopped. Thereafter, similarly to the above, the extraction of the refrigerant gas from the first tank 8 is started.

Further, when the second tank 12 is provided, the compressed refrigerant is stored in the second tank 12 when the load side becomes a low load or the load suddenly decreases. On the other hand, when the load side becomes a high load or the load suddenly rises, the refrigerant gas is taken out from the second tank 12.
As a result, it is possible to cope with fluctuations in heat load. In addition, since the refrigerant stored in the second tank 12 can cope with an excessive heat load, the equipment capacity of the refrigeration system 2 can be optimized. Furthermore, rapid start-up is possible by the refrigerant stored in the second tank.

Next, a method for designing the refrigeration systems 1 and 2 according to the present embodiment will be described.
Acquires the change over time of the heat load to be cooled. The temporal change of the thermal load is divided into, for example, a high load time zone and a low load time zone.
Next, the heat storage capacity of the first tank 8 and the equipment capacity of the compressor 3 of the refrigeration systems 1 and 2 are determined. Specifically, when the load is high, the load is borne by the refrigeration systems 1 and 2 including the first tank 8 and the compressor 3. On the other hand, when the load is low, the load is borne by the refrigeration systems 1 and 2 including the compressor 3 and the surplus of the equipment capacity of the refrigeration systems 1 and 2 is the refrigerant stored in the first tank 8. Used for generation.
Therefore, the installed capacity of the refrigeration systems 1 and 2 is set so that the heat storage capacity of the refrigerant taken out from the first tank 8 in the high load time period is equal to the heat storage capacity of the refrigerant generated and stored in the low load time period. Is determined.

  In addition, although the said embodiment demonstrated the case where the expansion valve 6 was used in order to expand the refrigerant | coolant condensed with the condenser 5, this invention is not limited to this example. For example, an expansion turbine may be installed instead of the expansion valve 6. The expansion turbine is connected to the rotating shaft of the generator via the rotating shaft. In the expansion turbine, the blades and the rotating shaft rotate when the refrigerant passes, and the generator generates power by the rotational force of the expansion turbine.

Further, the present invention is not limited to the above-described embodiment. For example, in the above-described reference embodiment, the second tank 12, the expansion valve 13, and the supply pump 24 described in the first embodiment may be included.

1, 2 Refrigeration system 3 Compressor (first compressor)
4,11 Electric motor 5 Condenser 6 Expansion valve (first expansion part)
7 Evaporator 8 1st tank (1st storage part)
9 Precooler 10 Recovery compressor 12 2nd tank (2nd storage part)
13 Expansion valve (second expansion part)
21 Cooling water pump 22 Cooler 23 Cooling water pump 24 Supply pump L1, L2, L3, L4 Piping

Claims (6)

A first storage part for temporarily storing the refrigerant;
A first compressor for compressing the refrigerant;
A condenser for condensing the refrigerant stored in the first storage part together with the refrigerant compressed by the first compressor;
A first expansion section for expanding the refrigerant condensed in the condenser;
An evaporator that exchanges heat with the object to be cooled and evaporates the refrigerant expanded in the first expansion section;
A second compressor that compresses the refrigerant evaporated in the evaporator and stores the refrigerant in the first storage unit;
With
The first storage unit stores the refrigerant evaporated by the evaporator and compressed by the second compressor according to the heat load to be cooled, or the refrigerant stored by the first storage unit. A refrigeration system for supplying to the condenser. A second storage part for temporarily storing the refrigerant;
The second storage unit stores the refrigerant expanded in the first expansion unit, supplies the refrigerant stored in the second storage unit to the evaporator, stores the refrigerant evaporated in the evaporator, and The refrigeration system according to claim 1 , wherein the refrigerant stored in the second storage unit is supplied to the first compressor. The refrigeration system according to claim 2 , further comprising a second expansion unit that expands the refrigerant evaporated by the evaporator and supplies the expanded refrigerant to the second storage unit. The refrigeration system according to any one of claims 1 to 3 , wherein the first expansion section is an expansion turbine, and a rotation shaft of the expansion turbine is connected to a rotation shaft of a generator. A first storage part for temporarily storing the refrigerant;
A first compressor for compressing the refrigerant;
A condenser for condensing the refrigerant stored in the first storage part together with the refrigerant compressed by the first compressor;
A first expansion section for expanding the refrigerant condensed in the condenser;
An evaporator that exchanges heat with the object to be cooled and evaporates the refrigerant expanded in the first expansion section;
A second compressor that compresses the refrigerant evaporated in the evaporator and stores the refrigerant in the first storage unit;
A method for operating a refrigeration system comprising:
Storing the refrigerant evaporated in the evaporator and compressed in the second compressor in the first storage unit according to the heat load to be cooled;
Supplying the refrigerant stored in the first storage unit to the condenser according to the heat load to be cooled;
Method of operating a refrigeration system including A first storage part for temporarily storing the refrigerant;
A first compressor for compressing the refrigerant;
A condenser for condensing the refrigerant stored in the first storage part together with the refrigerant compressed by the first compressor;
A first expansion section for expanding the refrigerant condensed in the condenser;
An evaporator that exchanges heat with the object to be cooled and evaporates the refrigerant expanded in the first expansion section;
A second compressor that compresses the refrigerant evaporated in the evaporator and stores the refrigerant in the first storage unit;
Equipped with a,
The first storage unit stores the refrigerant evaporated by the evaporator and compressed by the second compressor according to the heat load to be cooled, or the refrigerant stored by the first storage unit. A refrigeration system design method for supplying to the condenser ,
Obtaining a change in the thermal load of the cooling target;
Determining the capacity of the first reservoir based on the obtained fluctuation of the thermal load;
Method of designing a refrigeration system including

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