JP5783790B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus having two independent refrigeration circuits using a water-cooled condenser and a common evaporator.

  The thing described in the following patent document 1 is known as what uses a water-cooled condenser for the refrigerating circuit. The water-cooled condenser has, for example, a double pipe structure, and the outer pipe serves as a condenser pipe and the refrigerant flows in one direction, while the inner pipe serves as a water supply pipe and the cooling water flows in a direction opposite to the refrigerant. The refrigerant is condensed by heat exchange. Also, a water supply control valve is provided on the outlet side of the water supply pipe. For example, the high pressure of the refrigeration circuit is kept constant by controlling the water supply amount by opening and closing based on the detected pressure on the outlet side of the condenser (condenser pipe) Measures are taken to maintain

  On the other hand, in recent years, the following are known as refrigeration apparatuses having a wide range of refrigeration capabilities. In this structure, two independent refrigeration circuits are provided, an inverter compressor is provided in the first refrigeration circuit, a constant speed compressor is provided in the second refrigeration circuit, and an evaporator is shared by both refrigeration circuits. In general, only the first refrigeration circuit, that is, the inverter compressor is driven. Specifically, the cooling operation (control cooling operation) is performed while controlling the rotation speed of the inverter compressor, and the first refrigeration circuit ( When it is determined that the capacity is insufficient only on the inverter compressor side), the second refrigeration circuit, that is, the constant speed compressor is driven together.

JP 2006-292258 A

Here, when the refrigeration apparatus as described above is constructed by two independent refrigeration circuits each using a water-cooled condenser, a cooling water supply pipe and a water supply control valve including a feedback path are separately provided. As a result, the number of parts is increased, the piping is complicated, and a large arrangement space is required, and the assembly workability is inferior, leading to an increase in manufacturing cost.
The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a refrigeration apparatus that realizes a reduction in manufacturing cost by reducing the number of parts.

  The present invention is provided with two independent refrigeration circuits each equipped with a water-cooled condenser, and a main compressor operated mainly in the first refrigeration circuit and an auxiliary operation in the second refrigeration circuit. A refrigeration apparatus provided with an auxiliary compressor to be used, and an evaporator shared by both the refrigeration circuits, wherein a water supply pipe for circulating cooling water for cooling the first condenser of the first refrigeration circuit, A water supply pipe for circulating cooling water for cooling the second condenser of the second refrigeration circuit is connected in series so that the water supply pipe on the second refrigeration circuit side is located on the upstream side, and the first refrigeration circuit This is characterized in that a feed water control valve for controlling the amount of cooling water is provided on the outlet side of the feed water pipe on the side so as to maintain the high pressure of the first refrigeration circuit constant.

Cooling water flows along the two water supply pipes connected in series from the second condenser to the first condenser, and during this time, the water supply control valve cools the high pressure of the first refrigeration circuit to be kept constant. The amount of water is controlled. When only the main compressor of the first refrigeration circuit is operated, the high pressure of the first refrigeration circuit is maintained at a constant level so that the condensation temperature is properly maintained and the necessary refrigeration capacity is obtained. .
When the main compressor and the auxiliary compressor are operated simultaneously, the cooling water first cools the second condenser by heat exchange, and after the temperature is raised, acts to cool the first cooler by heat exchange. . At that time, the amount of the cooling water is controlled so that the high pressure of the first refrigeration circuit is constant, that is, an appropriate condensation temperature, but the second condensation located upstream from the first condenser. Since the condenser is heat-exchanged at a lower water temperature than the first condenser side, the condensation temperature on the second refrigeration circuit side is maintained lower than that on the first refrigeration circuit side.

That is, a single water supply pipe is integrated, and a water supply control valve for controlling the amount of water is provided at one location at the outlet of the water supply pipe on the first refrigeration circuit side, while the main compressor is operating alone and In any case where the compressor and the auxiliary compressor are operated together, it is possible to obtain an appropriate condensing temperature and thus a refrigerating capacity of both refrigeration circuits.
In other words, it is not necessary to provide a water supply pipe and a water supply control valve dedicated to the second refrigeration circuit, and only one water supply pipe and one water supply control valve need be provided, reducing the number of parts and piping work. In addition, the space can be saved and the product can be reduced in size, and the manufacturing cost can be greatly reduced.

The following configuration may also be used.
(1) The first condenser and the second condenser are both formed by a spirally wound condenser tube, and the first condenser is coaxially stacked above the second condenser. The single water supply pipe formed by connecting the two water supply pipes in series is inserted into the spiral from the lower end of the second condenser to the upper end of the first condenser. The double piping structure is configured such that the cooling water and the refrigerant are circulated in the opposite direction.

  The cooling water flows through the spiral single water supply pipe from the lower side to the upper side, cools the refrigerant by first exchanging heat with the refrigerant flowing from the upper side to the lower side in the second condensing pipe, and then the first condensation. This is cooled by exchanging heat with the refrigerant flowing from above to below in the pipe. Since the first condensing pipe and the second condensing pipe, both of which form a spiral shape, are vertically stacked, it is possible to realize further space saving on the installation surface.

(2) The main compressor provided in the first refrigeration circuit is an inverter compressor, and the auxiliary compressor provided in the second refrigeration circuit is a constant speed compressor.
Usually, the cooling operation is performed by an inverter compressor, and when the capacity is insufficient, the constant speed compressor is also driven, so that the refrigeration capacity can be efficiently exhibited over a wide range.

  According to the refrigeration apparatus of the present invention, the number of parts can be reduced and piping work can be simplified, and the space can be saved to contribute to the downsizing of the product, thereby greatly reducing the manufacturing cost. Is possible.

The circuit block diagram of the freezing apparatus which concerns on one Embodiment of this invention. The top view which shows the arrangement structure of the freezing apparatus Side sectional view of the refrigeration unit installation

<Embodiment>
An embodiment of the present invention will be described with reference to FIGS. In this embodiment, the freezing apparatus mounted in the vertical refrigerator for business is illustrated.
As shown in FIG. 3, the refrigerator includes a refrigerator main body 10 formed of a heat-insulating box having an opening on the front side. The inside of the refrigerator is a refrigerating chamber 11. It is mounted so that it can be opened and closed. On the upper surface of the refrigerator main body 10, a machine room 14 is configured by a panel standing around.

  A rectangular opening 15 is formed at substantially the center of the ceiling wall 10A of the refrigerator main body 10 serving as the bottom surface of the machine room 14, and a unit that will be described in detail later is formed so as to close the upper surface of the opening 15. A unit table 20 on which the refrigeration apparatus 30 is mounted is placed. Below the opening 15, a cooling duct 22 that also serves as a drain pan is stretched downwardly toward the back side (the right side in FIG. 3), and an evaporator chamber 23 is formed between the unit base 20. ing. A suction port 25 is formed on the front end side of the cooling duct 22, and an internal fan 26 is provided on the back surface thereof, and an air outlet 27 is formed on the rear end side of the cooling duct 22.

The refrigeration apparatus 30 includes two independent refrigeration circuits, that is, a first refrigeration circuit 31A and a second refrigeration circuit 31B, and the refrigeration circuits 31A and 31B have different compressors from each other, but an evaporator. 37 is shared, and both condensers are water-cooled condensers.
As schematically shown in the refrigeration circuit of FIG. 1, the first refrigeration circuit 31A includes an inverter compressor 32A having a variable rotation speed and a first water-cooled condenser 33A (hereinafter simply referred to as a first condenser 33A). And a dryer 35A, a capillary tube 36A as decompression means, and a common evaporator 37 are circulated through a refrigerant pipe. In the first refrigeration circuit 31 </ b> A, an accumulator 38 is interposed in the refrigerant pipe on the outlet side of the evaporator 37.

The second refrigeration circuit 31B includes a constant speed compressor 32B having a constant rotation speed, a second water-cooled condenser 33B (hereinafter simply referred to as a second condenser 33B), a dryer 35B, and a capillary tube 36B serving as a decompression unit. And a common evaporator 37 are circulated and connected by a refrigerant pipe.
Further, in both the first refrigeration circuit 31A and the second refrigeration circuit 31B, the refrigerant pipes on the inlet side and the outlet side of the evaporator 37 are in close contact with each other, and are accommodated in the heat insulating tube, whereby the heat exchanging part 39A. , 39B are formed.

  A water-cooled condenser 40 is formed by arranging and integrating a single water supply pipe 41 with both the condensers 33A and 33B. Specifically, the water supply pipe 41 is formed by connecting a water supply pipe 41A for cooling the first condenser 33A and a water supply pipe 41B for cooling the second condenser 33B in series with the water supply pipe 41B being the upstream side. Has been. In the water supply pipe 41, cooling water is circulated from the water supply port 42X toward the drain port 42Y.

  A water supply control valve 45 for controlling the amount of cooling water is provided at the end of the water supply pipe 41 on the drain outlet 42Y side so as to maintain the high pressure of the first refrigeration circuit 31A constant. More specifically, a detection unit 46 that detects the pressure on the high-pressure side of the first refrigeration circuit 31A is set downstream of the dryer 35A in the first refrigeration circuit 31A, and is connected to the water supply control valve 45 by a feedback path 47. ing. Then, the high pressure of the first refrigeration circuit 31A is maintained constant by opening and closing the water supply control valve 45 based on the fed back detected pressure and controlling the amount of cooling water. Further, high pressure switches 49A and 49B are provided on the discharge sides of the compressors 32A and 32B in both the refrigeration circuits 31A and 31B, respectively.

A more specific arrangement structure will be described. As shown in FIG. 2, the components of the first refrigeration circuit 31A are located at a position slightly shifted to the right side from the center in the width direction in the rear region on the unit base 20. Among them, an inverter compressor 32A, a dryer 35A, and a capillary tube 36A are installed, and on the left side of the components of the second refrigeration circuit 31B, a constant speed compressor 32B, a dryer 35B, and a capillary tube are installed. 36B is installed.
Here, the rotation speed of the inverter compressor 32A is variable over a plurality of stages (for example, seven stages).
The constant speed compressor 32B can be driven at a constant rotational speed less than the maximum speed (seventh speed) of the inverter compressor 32A. That is,
The maximum speed (7th speed) of the inverter compressor 32A> the rotational speed of the constant speed compressor 32B.
More specifically,
Maximum speed (7th speed) of inverter compressor 32A <{Minimum speed (1st speed) of inverter compressor 32A + Rotational speed of constant speed compressor 32B}
And
Further, {the highest speed of the inverter compressor 32A (7th speed) + the rotation speed of the constant speed compressor 32B} is set so as to satisfy the maximum refrigeration capacity necessary for the refrigerator.

An integrated water-cooled condenser 40 is installed at a position on the front side of the first refrigeration circuit 31A.
The water-cooled condenser 40 has a double tube structure spirally wound. More specifically, the first condenser 33A and the second condenser 33B are both configured by a spirally wound condensation tube, and the first condenser 33A is coaxially stacked above the second condenser 33B. Has been placed. In each of the condensers 33A and 33B, the refrigerant flows from the upper side to the lower side.

On the other hand, the single water supply pipe 41 is formed in the form of an inner pipe that is continuously fitted in a spiral shape from the second condenser 33B to the first condenser 33A. The water supply pipe 41 has an inlet 41X at the lower end and an outlet 41Y at the upper end, and the cooling water flows from the lower side to the upper side so as to face the refrigerant flowing through the condensers 33B and 33A.
At the left end of the front side region on the upper surface of the unit base 20, a cooling water supply port 42X and a drain port 42Y are provided side by side on the back side and the front side, and are drawn from the inlet 41X of the water supply pipe 41 described above. The inlet pipe 44X thus connected is connected to the water supply port 42X, and the outlet pipe 44Y drawn from the outlet 41Y of the water supply pipe 41 is connected to the drainage port 42Y.

A water supply control valve 45 is interposed in the outlet pipe 44Y of the water supply pipe 41, and a feedback path 47 drawn from the high pressure detector 46 set downstream of the dryer 35A in the first refrigeration circuit 31A, A water supply control valve 45 is connected.
High-pressure switches 49A and 49B are connected to the refrigerant pipe on the discharge side of the inverter compressor 32A in the first refrigeration circuit 31A and the refrigerant pipe on the discharge side of the constant speed compressor 32B in the second refrigeration circuit 31B, respectively. .
A cooling fan 50 for the compressor 32B is provided on the front side of the constant speed compressor 32B.

On the other hand, a common evaporator 37 is suspended and attached to the lower surface side of the unit table 20 to form a unit.
When the unit table 20 assembled with the refrigeration apparatus 30 in this way is placed so as to close the opening 15 of the ceiling wall 10A of the freezer body 10, the evaporator 37 becomes the evaporator chamber 23 as shown in FIG. It is housed in a position on the back side of the internal fan 26 inside.
Basically, when the refrigeration apparatus 30 and the internal fan 26 are driven, the air in the refrigerating chamber 11 is sucked into the evaporator chamber 23 from the suction port 25 as shown by the arrow in FIG. The cold air generated by the heat exchange while passing through the evaporator 37 is circulated such that the cold air is blown out from the outlet 27 to the refrigerator compartment 11, thereby cooling the inside of the refrigerator compartment 11. Is to be controlled.

Then, the effect | action of this embodiment is demonstrated.
In this embodiment, the acceleration / deceleration control of the inverter compressor 32A is performed so that the internal temperature follows a predetermined control cooling characteristic. Specifically, in the operation control unit, the control cooling characteristic is stored in advance as data of a temporal change mode of the target temperature drop, and during the cooling operation, the internal temperature is changed every predetermined sampling time. The sensor detects the internal temperature, and the actual temperature drop is calculated based on the detected temperature. On the other hand, the target temperature drop at the internal temperature is output from the stored data. If the temperature drop degree is smaller than the target temperature drop degree, the inverter compressor 32A is controlled to increase the speed. In the opposite case, the inverter compressor 32A is controlled to decelerate or stop. To be cooled.

During this time, if it is determined that the capacity of the inverter compressor 32A alone is insufficient due to an increase in the internal load or an increase in the ambient temperature, for example, the inverter compressor 32A still increases after reaching the maximum rotational speed (7th speed). When a request is issued, the constant speed compressor 32B is driven together.
For example, when a request for higher speed is made, in addition to driving the constant speed compressor 32B, the inverter compressor 32A is driven at the minimum number of revolutions (first speed), and further speed increase is requested. The inverter compressor 32A is increased to “second speed”.

  During such a cooling operation, after the cooling water is supplied from the water supply port 42X, the single water supply pipe 41 having a spiral shape constituting the inner pipe of the water-cooled condenser 40 is circulated from below to above, First, the refrigerant flows through the second condenser 33B to exchange heat with the refrigerant, and then flows through the first condenser 33A to exchange heat with the refrigerant, and then is discharged from the drain port 42Y. Further, during this period, the water supply control valve 45 controls the amount of cooling water so as to maintain the high pressure of the first refrigeration circuit 31A constant.

When only the inverter compressor 32A of the first refrigeration circuit 31A is operated, the condensation temperature is properly maintained by maintaining the high pressure of the first refrigeration circuit 31A constant, and the necessary refrigeration capacity Is obtained.
When the inverter compressor 32A and the constant speed compressor 32B are operated simultaneously, the cooling water first cools the second condenser 33B by heat exchange, and after the temperature is raised, the first condenser 33A is cooled by heat exchange. Acts like At that time, the amount of the cooling water is controlled so that the high pressure of the first refrigeration circuit 31A is constant, that is, an appropriate condensing temperature, but the first is located upstream of the first condenser 33A. Since the 2 condenser 33B performs heat exchange at a lower water temperature than the first condenser 33A side, the condensation temperature on the second refrigeration circuit 31B side is maintained lower than that on the first refrigeration circuit 31A side.
When the water is shut off, or when the inverter compressor 32A cannot be operated and only the constant speed compressor 32B is operated, the high pressure switches 49A and 49B provided in the respective refrigeration circuits 31A and 31B detect the increase in the high pressure. The compressors 32A and 32B are stopped and protected.

As described above, in this embodiment, the water supply pipes 41A and 41B of the first refrigeration circuit 31A and the second refrigeration circuit 31B are combined into a single water supply pipe 41, and the water supply control valve 45 for controlling the amount of water is connected to the water supply pipe 41. Of these, the inverter compressor 32A and the constant speed compressor 32B are combined with each other while being provided at one location on the outlet side of the water supply pipe 41A on the first refrigeration circuit 31A side. In both cases, it is possible to obtain the proper condensation temperature of both the refrigeration circuits 31A and 31B, and thus the refrigeration capacity.
In other words, it is not necessary to provide a dedicated water supply pipe and a water supply control valve for the second refrigeration circuit 31B, and only a single water supply pipe 41 and one water supply control valve 45 may be provided, reducing the number of parts. Piping work can be simplified, and space can be saved to contribute to downsizing of the product, which can greatly reduce the manufacturing cost.

  Further, the integrated water-cooled condenser 40 is formed by a condensing tube in which the first condenser 33A and the second condenser 33B are spirally wound together, and the first condenser 33A is disposed above the second condenser 33B. And the single water supply pipe 41 from the lower end of the second condenser 33B to the upper end of the first condenser 33A with a spiral double pipe structure inserted inside them, It is compact in a plan view and can realize further space saving on the installation surface.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) In the above embodiment, the case where an inverter compressor is used as a main compressor and a constant compressor is used as an auxiliary compressor is exemplified, but both are inverter compressors or both are applied constant speed compressors. It may be.
(2) The water-cooled condenser is not limited to the double tube type exemplified in the above embodiment, but may be of other types such as a shell-tube type.
(3) The present invention is not limited to the commercial refrigerators exemplified in the above embodiment, but can be widely applied to refrigeration apparatuses equipped in other cooling storages such as a freezer, a refrigerator, a constant temperature and high humidity storage. it can.

  DESCRIPTION OF SYMBOLS 30 ... Refrigeration apparatus 31A ... 1st refrigeration circuit 31B ... 2nd refrigeration circuit 32A ... Inverter compressor (main compressor) 32B ... Constant speed compressor (auxiliary compressor) 33A ... 1st condenser 33B ... 2nd condenser 37 ... Evaporator 40 ... Water-cooled condenser 41 ... Water supply pipe (single water supply pipe) 41A, 41B ... Water supply pipe 44Y ... Outlet pipe 45 ... Water supply control valve 46 ... (high pressure) detector 47 ... Feedback path

Claims (3)

Two independent refrigeration circuits, both equipped with water-cooled condensers, are provided, the main refrigeration circuit is mainly operated in the first refrigeration circuit, and the capacity of the second refrigeration circuit is insufficient with only the main compressor. A refrigeration apparatus provided with an auxiliary compressor that is driven in conjunction with the main compressor when it is determined to be operated in an auxiliary manner, and an evaporator is shared in both the refrigeration circuits,
A water supply pipe for circulating cooling water for cooling the first condenser of the first refrigeration circuit and a water supply pipe for circulating cooling water for cooling the second condenser of the second refrigeration circuit are the second refrigeration circuit. The amount of cooling water is connected in series so that the water supply pipe on the side is located on the upstream side, and the high pressure of the first refrigeration circuit is kept constant at the outlet side of the water supply pipe on the first refrigeration circuit side. A water supply control valve is provided to control the
A refrigeration apparatus, wherein a high pressure switch is provided on a discharge side of the main compressor in the first refrigeration circuit and on a discharge side of the auxiliary compressor in the second refrigeration circuit . The first condenser and the second condenser are both formed by a spirally wound condenser tube, and the first condenser is coaxially stacked above the second condenser, A single water supply pipe formed by connecting the water supply pipes in series is inserted into them from the lower end of the second condenser to the upper end of the first condenser, thereby forming a spiral double pipe. 2. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus has a piping structure, and the cooling water and the refrigerant are circulated in opposite directions.   3. The main compressor provided in the first refrigeration circuit is an inverter compressor, and the auxiliary compressor provided in the second refrigeration circuit is a constant speed compressor. Refrigeration equipment.

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