JP2011220616A - Refrigeration apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration apparatus which has improved efficiency of heat exchange by controlling flow velocity of a refrigerant suitably, and reducing a pressure loss suitably when the flow velocity of the refrigerant is made high.SOLUTION: The refrigeration apparatus 1 includes: a refrigerant circuit formed by connecting a compressor 10 having variable operation capacity, a plurality of condensers 42, an expansion valve 20 and a plurality of evaporators 32 by refrigerant piping 1a; and a changeover mechanism for changing over an operation state from/to such a series state that the plurality of condensers 42 are connected to one another in series with a flow of the refrigerant Rf and the plurality of evaporators 32 are connected to one another in series with the flow of the refrigerant Rf, to/from such a parallel state that the plurality of condensers 42 are connected to one another in parallel with the flow of the refrigerant Rf and the plurality of evaporators 32 are connected to one another in parallel with the flow of the refrigerant Rf. According to the operation capacity of the compressor 10, the operation state is changed over by the changeover mechanism from/to the series state to/from the parallel state.

Description

  The present invention relates to a refrigeration apparatus having a heat exchanger.

A refrigerating apparatus that has a refrigerant circuit in which a refrigerant circulates and a heat exchanger and cools water to be cooled is widely known.
As a technique for improving the efficiency of heat exchange of such a refrigeration apparatus, for example, Patent Document 1 includes two coolers (evaporators) that cool brine (liquid to be cooled) as heat exchangers. A cooling device (refrigeration device) capable of switching the connection of two coolers in series or in parallel is disclosed.
The cooling device disclosed in Patent Document 1 includes a refrigerant circuit that can switch the connection of two coolers in series or in parallel, and the series and parallel of the connections of the two coolers based on the temperature of the refrigerant or brine, for example. The efficiency of heat exchange is improved by switching.

  Patent Document 2 discloses a refrigeration air-conditioning apparatus (refrigeration apparatus) that improves the efficiency of heat exchange by suitably controlling the operating capacity of the compressor.

According to the cooling device disclosed in Patent Document 1, in the initial stage of cooling, two coolers are connected in parallel to reduce the flow rate of the refrigerant to reduce the pressure loss, and the temperature of the refrigerant and brine reaches a predetermined temperature. Sometimes the efficiency of heat exchange in the cooler can be improved by connecting two coolers in series to increase the flow rate.
Moreover, the efficiency of heat exchange in the cooler can be improved by switching the connection of the two coolers based on the pressure of the coolant (refrigerant evaporation pressure).

  Further, according to the refrigeration air conditioner disclosed in Patent Document 2, when the load-side heat medium (liquid to be cooled) such as water or brine flows into the refrigeration cycle of the refrigeration air conditioner, and when it flows out of the refrigeration cycle By controlling the operating capacity of the compressor so that the temperature difference between the two becomes a predetermined value, the efficiency of heat exchange of the refrigeration air conditioner can be improved.

Japanese Patent Laid-Open No. 10-267494 JP 2008-175476 A

For example, when the connection of two coolers is switched in series or in parallel as in the cooling device disclosed in Patent Document 1, the two coolings are performed when the flow rate of the refrigerant discharged from the compressor is increased as in the early stage of refrigeration. When the connection of the units is switched in parallel, the pressure loss with respect to the refrigerant flow can be reduced, and the refrigerant can be efficiently circulated to the cooler while maintaining a high flow rate of the refrigerant. And a refrigerant | coolant and brine can be heat-exchanged effectively with a cooler.
On the other hand, when the flow rate of the refrigerant discharged from the compressor is low, two refrigerants are connected in series to increase the flow rate of the refrigerant in the cooler, so that the two coolers can effectively remove the refrigerant and brine. Heat exchange is possible.

  However, since the refrigerant temperature and refrigerant evaporation pressure, which serve as a reference for switching the connection between the two coolers in Patent Document 1, change regardless of changes in the refrigerant flow rate in the refrigerant circuit, the refrigerant temperature and refrigerant evaporation pressure are changed. When the connection of the two coolers is switched according to the above, there is a problem that the connection of the two coolers cannot be switched at the optimum refrigerant flow rate for switching the connection of the two coolers.

  In addition, for example, when the cooling device is provided with a compressor having a variable operating capacity disclosed in Patent Document 2, the refrigerant flow rate (refrigerant flow velocity) changes according to the change in the operating capacity of the compressor. If the connection of the two coolers is switched based on the temperature and the refrigerant evaporating pressure, the connection of the two coolers cannot be switched at the optimum refrigerant flow rate for switching the connection of the two coolers.

  Further, the refrigeration apparatus includes a heat exchanger (condenser) for condensing the refrigerant in addition to a heat exchanger (cooler) for evaporating the refrigerant. And since the refrigerant | coolant pressure loss generate | occur | produces also in a condenser, the efficiency of the heat exchange of a freezing apparatus can further be improved by reducing suitably the pressure loss of a condenser.

  Therefore, an object of the present invention is to provide a refrigeration apparatus that suitably controls the flow rate of the refrigerant and also reduces the pressure loss when the flow rate of the refrigerant is high, thereby improving the efficiency of heat exchange.

  In order to solve the above-described problems, the present invention includes a refrigerant circuit in which a compressor having a variable operating capacity, a plurality of condensers, an expansion valve, and a plurality of evaporators are connected by a conduit through which the refrigerant flows. Refrigeration equipment. And connecting the plurality of condensers in series with the refrigerant flow and connecting the plurality of evaporators in series with the refrigerant flow; and connecting the plurality of condensers to the refrigerant flow. A switching mechanism for switching between the parallel connection to the flow and the parallel state in which the plurality of evaporators are connected in parallel to the refrigerant flow, and the switching mechanism according to the operating capacity of the compressor. The serial state and the parallel state are switched.

According to the present invention, the series and parallel of the connections of the plurality of condensers and the series and parallel of the connections of the plurality of evaporators can be switched according to the operating capacity of the compressor.
Therefore, according to the refrigerant | coolant flow velocity which changes according to the operating capacity of a compressor, the series and parallel of the connection of a some condenser and the series and parallel of the connection of a some evaporator can be switched.

  According to the present invention, it is possible to provide a refrigeration apparatus that suitably controls the flow rate of the refrigerant and reduces the pressure loss when the flow rate of the refrigerant is high, thereby improving the efficiency of heat exchange.

It is a figure which shows the structure of the freezing apparatus which concerns on this embodiment. (A) is a partially broken view of a laminated plate heat exchanger, and (b) is a cross-sectional view of a shell and tube heat exchanger. (A) is a figure showing the state where the 1st condenser and the 2nd condenser were connected in parallel, (b) is the figure showing the state where the 1st condenser and the 2nd condenser were connected in series. is there. It is a flowchart which shows the procedure in which a control apparatus controls a freezing apparatus. (A) is a figure which shows the structure provided with a three-way valve in the branch point of a 1st condensing pipe and a bypass pipe, (b) is a figure which shows a condensing circuit provided with three condensers. It is a figure which shows a condensation circuit provided with the condenser which consists of a heat exchange module which has two heat exchange parts.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
As shown in FIG. 1, the refrigeration apparatus 1 according to the present embodiment includes a compressor 10, a condensing circuit 40, an expansion valve 20, and an evaporation circuit 30, in this order, in series, a conduit through which refrigerant flows (refrigerant piping 1 a) And is controlled by the control device 50.

The gaseous refrigerant Rf compressed to high temperature and high pressure by the compressor 10 is cooled and condensed by exchanging heat with low temperature water (refrigerant cooling water Wt1) flowing through the water pipe 41 in the condensing circuit 40. It flows into the expansion valve 20 in a state. The low-temperature refrigerant Rf is expanded by the expansion valve 20 and is in a state where the temperature is lowered and is easily evaporated. Then, it evaporates by exchanging heat with relatively high-temperature water (cooled water Wt2) flowing through the water pipe 31 in the evaporation circuit 30, becomes gaseous, and flows into the compressor 10. At this time, the relatively high temperature water to be cooled Wt2 flowing through the water pipe 31 is cooled by the heat of vaporization of the refrigerant Rf.
Hereinafter, upstream and downstream indicate upstream and downstream of the flow of the refrigerant Rf in the refrigerant circuit. Further, the series indicates a series with respect to the flow of the refrigerant Rf, and the parallel indicates a parallel with the flow of the refrigerant Rf.

The condensing circuit 40 is connected to the downstream of the compressor 10 by the refrigerant | coolant piping 1a.
The refrigerant pipe 1a is branched into a first condensing pipe 43a and a second condensing pipe 43b serving as a diversion pipe at a branch point 40a formed on the upstream side of the condensing circuit 40, and the first condensing pipe 43a and the second condensing pipe 43b. Join at a joining point 40 b formed on the downstream side of the condensing circuit 40.
The condensing circuit 40 includes two condensers 42, a first condenser 42a and a second condenser 42b. The first condenser 42a is connected to the first condenser pipe 43a, and the second condenser pipe 43b is connected to the second condenser 42a. The condenser 42b is connected. That is, the first condensing pipe 43a and the second condensing pipe 43b are connected in parallel to the flow of the refrigerant Rf, and the first condenser 42a and the second condenser 42b are arranged in parallel.

  Both the first condenser 42a and the second condenser 42b are provided with a water pipe 41 through which the coolant cooling water Wt1 flows, and the refrigerant Rf through the first condenser pipe 43a is a water pipe that is piped into the first condenser 42a. Heat exchange with the coolant cooling water Wt1 flowing through 41 is cooled and condensed. In addition, the refrigerant Rf flowing through the second condensing pipe 43b exchanges heat with the refrigerant cooling water Wt1 flowing through the water pipe 41 piped to the second condenser 42b, and is cooled and condensed.

The condensers 42 (first condenser 42a and second condenser 42b) provided in the condenser circuit 40 are each constituted by a heat exchanger.
Although the kind of heat exchanger which comprises the condenser 42 is not limited, For example, the laminated plate type heat exchanger 60 shown to (a) of FIG. 2, and the shell and tube type shown to (b) of FIG. A heat exchanger 70 is used.

  As shown in FIG. 2A, the laminated plate heat exchanger 60 is configured by a plurality of heat transfer plates 63 sandwiched between a pair of end plates 61 and 62. The plurality of heat transfer plates 63 are, for example, arranged in parallel at equal intervals, and include a heat transfer plate 63 in which the flow path 63a of the refrigerant Rf is formed and a heat transfer plate 63 in which the flow path 63b of the coolant cooling water Wt1 is formed. Alternatingly arranged.

  The refrigerant Rf is taken into the laminated plate heat exchanger 60 from the refrigerant intake port 64a formed in one end plate 61, flows through the flow path 63a, and is discharged from the refrigerant discharge port 64b formed in the end plate 61. . Further, the coolant water Wt1 is taken into the laminated plate heat exchanger 60 from the liquid intake port 65a formed in the end plate 61 where the refrigerant intake port 64a is formed, flows through the flow path 63b, and is formed in the end plate 61. Is discharged from the liquid discharge port 65b. The refrigerant Rf and the refrigerant cooling water Wt1 exchange heat when flowing through the flow path 63a and the flow path 63b, respectively.

  In the first condenser 42a, the refrigerant intake port 64a and the refrigerant discharge port 64b are connected to the first condenser tube 43a (see FIG. 1), and in the second condenser 42b, the refrigerant intake port 64a and the refrigerant discharge port 64b. Is connected to the second condensing pipe 43b (see FIG. 1). The liquid intake port 65a and the liquid discharge port 65b are connected to the water pipe 41 (see FIG. 1).

  On the other hand, as shown in FIG. 2B, for example, the shell and tube heat exchanger 70 discharges the coolant intake water 71t and the coolant coolant Wt1 into the shell 71 forming the exterior. The liquid discharge port 71b to be formed is formed. A pipe 72 through which the refrigerant Rf flows is piped inside the shell 71, and the refrigerant cooling water Wt 1 that is taken into the shell 71 from the liquid intake port 71 a and discharged from the liquid discharge port 71 b, and the pipe line 72. The refrigerant Rf that circulates is configured to exchange heat.

  In the first condenser 42a, the pipe line 72 through which the refrigerant Rf flows is connected to the first condenser pipe 43a (see FIG. 1), and in the second condenser 42b, the pipe line 72 through which the refrigerant Rf flows is 2 is connected to the condenser tube 43b (see FIG. 1). The liquid intake port 71a and the liquid discharge port 71b are connected to the water pipe 41 (see FIG. 1).

Returning to FIG. The upstream side of the second condenser 42b and the downstream side of the first condenser 42a are connected by a bypass pipe 44 in which the first condensation pipe 43a and the second condensation pipe 43b branch at respective branch points 44a and 44b. 44 has a check valve 46. That is, the first condensing pipe 43 a and the second condensing pipe 43 b are connected by the bypass pipe 44.
With this configuration, the first condenser 42 a and the second condenser 42 b are arranged in series with respect to the flow of the refrigerant Rf via the bypass pipe 44.
The first condenser 42a is the most upstream condenser 42 arranged in series, and the second condenser 42b is the most downstream condenser 42 arranged in series. It becomes the condenser 42 located in this.

  The check valve 46 changes the flow direction of the refrigerant Rf in the bypass pipe 44 in one direction from the downstream side of the first condenser 42a to the upstream side of the second condenser 42b, that is, from the branch point 44a to the branch point 44b. This is a valve that regulates in one direction to prevent the refrigerant Rf from flowing from the upstream side of the second condenser 42b to the downstream side of the first condenser 42a.

  Further, the first condensing pipe 43a is provided with a first electromagnetic valve 45a comprising an on-off valve for opening and closing the first condensing pipe 43a between the junction 40b and the branch point 44a downstream of the first condenser 42a. Further, the second condensing pipe 43b is provided with a second electromagnetic valve 45b including an opening / closing valve for opening and closing the second condensing pipe 43b between the branching point 40a and the branching point 44b upstream of the second condenser 42b.

  When both the first electromagnetic valve 45a and the second electromagnetic valve 45b are opened, as shown in FIG. 3A, the refrigerant Rf flowing from the refrigerant pipe 1a into the condensing circuit 40 is branched at the branch point 40a. It flows through both the first condenser pipe 43a and the second condenser pipe 43b, joins at the junction 40b via the first condenser 42a and the second condenser 42b, respectively, and flows out from the condenser circuit 40.

At this time, the pressure of the refrigerant Rf at the branch point 44b (hereinafter referred to as the refrigerant pressure) becomes higher than the refrigerant pressure at the branch point 44a because of the pressure loss. Therefore, the bypass pipe 44 is provided with a check valve 46 to prevent the refrigerant Rf from flowing through the bypass pipe 44 from the branch point 44b toward the branch point 44a.
Since the refrigerant pressure at the branch point 44b is higher than the refrigerant pressure at the branch point 44a, the refrigerant Rf does not flow through the bypass pipe 44 from the branch point 44a toward the branch point 44b.

  As described above, when both the first electromagnetic valve 45a and the second electromagnetic valve 45b are opened, the refrigerant Rf flows in parallel through the first condenser 42a and the second condenser 42b. The two condensers 42b are connected in parallel.

  On the other hand, when both the first electromagnetic valve 45a and the second electromagnetic valve 45b are closed, the refrigerant Rf does not flow into the second condensing pipe 43b at the branch point 40a as shown in FIG. It flows only into the tube 43a. The refrigerant Rf flowing into the condensing circuit 40 from the refrigerant pipe 1a flows into the first condensing pipe 43a at the branch point 40a, flows through the bypass pipe 44 via the first condenser 42a, and into the second condensing pipe 43b. It flows out of the condenser circuit 40 via the condenser 42b and the junction 40b.

  Thus, when both the first electromagnetic valve 45a and the second electromagnetic valve 45b are closed, the refrigerant Rf flows through the second condenser 42b after flowing through the first condenser 42a. The two condensers 42b are connected in series.

  As described above, the condensing circuit 40 can switch the connection of the first condenser 42a and the second condenser 42b in series or in parallel by opening and closing the first electromagnetic valve 45a and the second electromagnetic valve 45b.

  The description returns to FIG. 1 again. The expansion valve 20 adiabatically expands and decompresses the refrigerant Rf condensed and liquefied by the first condenser 42a and the second condenser 42b of the condensation circuit 40, and makes the refrigerant Rf low temperature and low pressure. As the expansion valve 20, for example, an electric expansion valve having a high response speed of opening adjustment is used, and the refrigerant Rf flowing from the condensing circuit 40 is decompressed to be easily evaporated and sent to the evaporating circuit 30. The expansion valve 20 can adjust the circulation amount of the refrigerant Rf in the refrigerant circuit by adjusting the valve opening.

The evaporation circuit 30 is connected to the downstream side of the expansion valve 20 by a refrigerant pipe 1a.
The refrigerant pipe 1a branches into a first evaporation pipe 33a and a second evaporation pipe 33b that serve as branch pipes at a branch point 30a formed on the upstream side of the evaporation circuit 30, and the first evaporation pipe 33a and the second evaporation pipe 33b are They merge at a junction 30b formed on the downstream side of the evaporation circuit 30. The evaporation circuit 30 includes two evaporators 32, a first evaporator 32a and a second evaporator 32b. The first evaporator 32a is connected to the first evaporator pipe 33a, and the second evaporator 32b is connected to the second evaporator pipe 33b. The evaporator 32b is connected.
That is, the first evaporator pipe 33a and the second evaporator pipe 33b are connected in parallel with the flow of the refrigerant Rf, and the first evaporator 32a and the second evaporator 32b are arranged in parallel.

Both the first evaporator 32a and the second evaporator 32b are provided with a water pipe 31 through which the water to be cooled Wt2 flows, and the water to be cooled Wt2 flowing through the water pipe 31 piped into the first evaporator 32a Heat is exchanged with the refrigerant Rf flowing into the first evaporator 32a from the evaporation pipe 33a, and the heat of vaporization when the refrigerant Rf is vaporized is absorbed and cooled.
Further, the water to be cooled Wt2 flowing through the water pipe 31 piped to the second evaporator 32b exchanges heat with the refrigerant Rf flowing into the second evaporator 32b from the second evaporator pipe 33b, and is vaporized when the refrigerant Rf is vaporized. Heat is absorbed and cooled. The water pipe 31 is provided with a water temperature gauge 31a for measuring the temperature of the water to be cooled Wt2 after heat exchange is performed by the first evaporator 32a and the second evaporator 32b.

  Like the condenser 42, the evaporator 32 (first evaporator 32a, second evaporator 32b) provided in the evaporation circuit 30 is a laminated plate heat exchanger 60 (see FIG. 2A), It is configured by a heat exchanger such as a shell and tube heat exchanger 70 (see FIG. 2B).

The refrigerant cooling water Wt1 of the laminated plate heat exchanger 60 shown in FIG. 2A and the shell-and-tube heat exchanger 70 shown in FIG. 2B is the cooling water Wt2 in the evaporator 32. become.
In the evaporator 32 (see FIG. 1), the liquid intake port 65a and the liquid discharge port 65b of the laminated plate heat exchanger 60 and the liquid intake port 71a and the liquid discharge port 71b of the shell-and-tube heat exchanger 70 are: It connects with the water piping 31 (refer FIG. 1). Further, in the first evaporator 32a (see FIG. 1), the refrigerant intake port 64a and the refrigerant discharge port 64b of the laminated plate heat exchanger 60 and the pipe 72 of the shell and tube heat exchanger 70 are connected to the first evaporator tube. 33a, in the second evaporator 32b (see FIG. 1), the refrigerant intake port 64a and the refrigerant discharge port 64b of the laminated plate heat exchanger 60 and the pipe 72 of the shell-and-tube heat exchanger 70 are 2 is connected to the evaporation pipe 33b.

The upstream side of the second evaporator 32b and the downstream side of the first evaporator 32a are connected by a bypass pipe 34 in which the first evaporator pipe 33a and the second evaporator pipe 33b branch at respective branch points 34a and 34b. 34 is provided with a check valve 36.
That is, the first evaporation pipe 33 a and the second evaporation pipe 33 b are connected by the bypass pipe 34.
With this configuration, the first evaporator 32 a and the second evaporator 32 b are arranged in series with respect to the flow of the refrigerant Rf via the bypass pipe 34. The first evaporator 32a becomes the most upstream evaporator 32 among the evaporators 32 arranged in series, and the second evaporator 32b is the most among the evaporators 32 arranged in series. It becomes the evaporator 32 located downstream.

  The check valve 36 moves the refrigerant Rf in the bypass pipe 34 in one direction from the downstream side of the first evaporator 32a to the upstream side of the second evaporator 32b, that is, from the branch point 34a to the branch point 34b. It is a valve that regulates in one direction and prevents the refrigerant Rf from flowing from the upstream side of the second evaporator 32b to the downstream side of the first evaporator 32a.

Further, the first evaporation pipe 33a is provided with a third electromagnetic valve 35a composed of an opening / closing valve for opening and closing the first evaporation pipe 33a between the junction 30b and the branch point 34a downstream of the first evaporator 32a.
Further, the second evaporation pipe 33b is provided with a fourth electromagnetic valve 35b comprising an opening / closing valve for opening and closing the second evaporation pipe 33b between the branch point 30a and the branch point 34b upstream of the second evaporator 32b.

  In the evaporation circuit 30, similarly to the condensation circuit 40, when both the third electromagnetic valve 35 a and the fourth electromagnetic valve 35 b are opened, the first evaporator 32 a and the second evaporator 32 b are connected in parallel, and the third electromagnetic valve When both the valve 35a and the fourth electromagnetic valve 35b are closed, the first evaporator 32a and the second evaporator 32b are connected in series. That is, the evaporation circuit 30 can switch the connection between the first evaporator 32a and the second evaporator 32b in series or in parallel by opening and closing the third electromagnetic valve 35a and the fourth electromagnetic valve 35b.

The compressor 10 provided in the refrigeration apparatus 1 according to the present embodiment is configured to have a variable operating capacity.
For example, the compressor 10 is a scroll compressor including a DC brushless motor that is driven by an alternating current supplied from an inverter circuit. For example, the compressor 10 is controlled at a low speed (for example, 700 rpm) by controlling the frequency (driving frequency) of the alternating current. ) To a high speed (for example, 7000 rpm).
The compressor 10 has a large operating capacity when driven at a high speed and a small operating capacity when driven at a low speed. That is, the compressor 10 is configured to be able to control the rotational speed by controlling the driving frequency and to control the operating capacity by controlling the rotational speed.

  The control device 50 provided in the refrigeration apparatus 1 is provided in the rotation speed of the compressor 10, the opening degree of the expansion valve 20, the opening and closing of the first electromagnetic valve 45 a and the second electromagnetic valve 45 b provided in the condensation circuit 40, and the evaporation circuit 30. The operation of the refrigeration apparatus 1 is controlled by controlling the opening and closing of the third electromagnetic valve 35a and the fourth electromagnetic valve 35b.

For example, immediately after the start of the refrigeration apparatus 1, the temperature (water temperature) of the water to be cooled Wt2 cooled by the first evaporator 32a and the second evaporator 32b of the evaporation circuit 30 is much higher than a predetermined target temperature. The control device 50 operates the compressor 10 with a high operating capacity. That is, the compressor 10 is operated at a high speed (for example, 7000 rpm).
The compressor 10 is in a full load state with the maximum load, and the refrigerant Rf circulates in the refrigerant circuit at a high flow rate.

  Thereafter, when the water temperature of the to-be-cooled water Wt2 decreases to a predetermined temperature, the control device 50 decreases the operating capacity of the compressor 10. That is, the control device 50 reduces the rotational speed of the compressor 10 (for example, 700 rpm). As the operating capacity of the compressor 10 decreases, the flow rate of the refrigerant Rf flowing through the refrigerant circuit decreases.

  Furthermore, when the operating capacity of the compressor 10 is large and the flow rate of the refrigerant Rf circulating through the refrigerant circuit is high, the control device 50 according to this embodiment includes both the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40. The valve is opened, and both the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the evaporation circuit 30 are opened. The first condenser 42a and the second condenser 42b of the condenser circuit 40 are connected in parallel, and the refrigerant Rf flows through the first condenser 42a and the second condenser 42b in parallel. Similarly, the first evaporator 32a and the second evaporator 32b of the evaporation circuit 30 are connected in parallel, and the refrigerant Rf flows through the first evaporator 32a and the second evaporator 32b in parallel.

In addition, when the operating capacity of the compressor 10 is small and the flow rate of the refrigerant Rf circulating through the refrigerant circuit is low, the control device 50 closes both the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40 and evaporates. Both the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the circuit 30 are closed.
The first condenser 42a and the second condenser 42b of the condensing circuit 40 are connected in series, and the refrigerant Rf flows through the first condenser 42a and the second condenser 42b in series. Similarly, the first evaporator 32a and the second evaporator 32b of the evaporation circuit 30 are connected in series, and the refrigerant Rf flows through the first evaporator 32a and the second evaporator 32b in series.

  The flow rate of the refrigerant Rf flowing through the condensing circuit 40 and the evaporating circuit 30 (hereinafter, the condensing circuit 40 and the evaporating circuit 30 are collectively referred to as a heat exchange circuit) is proportional to the operating capacity of the compressor 10, and the operating capacity of the compressor 10 is When it is large, the flow rate of the refrigerant Rf flowing through the heat exchange circuit is high, and when the operating capacity of the compressor 10 is small, the flow rate of the refrigerant Rf flowing through the heat exchange circuit is also low.

  In the heat exchange circuit, the higher the flow rate of the refrigerant Rf, the higher the efficiency of heat exchange. However, the refrigerant Rf and the refrigerant flow path (the first condensing pipe 43a, the second condensing pipe 43b, the first evaporating pipe 33a, the first evaporating pipe 33a, 2) Pressure loss due to friction with the evaporation tube 33b) increases.

  Therefore, the control device 50 of the refrigeration apparatus 1 according to the present embodiment operates the first condenser 42a and the second condenser 42b of the condenser circuit 40 when the compressor 10 is operated at a large operating capacity (high rotational speed). The connection and the connection of the first evaporator 32a and the second evaporator 32b of the evaporation circuit 30 are both switched in parallel to reduce pressure loss in the heat exchange circuit. Specifically, the control device 50 opens both the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40, and opens both the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the evaporation circuit 30. Thus, the connection between the first condenser 42a and the second condenser 42b in the condenser circuit 40 and the connection between the first evaporator 32a and the second evaporator 32b in the evaporator circuit 30 are switched in parallel, and the pressure loss in the heat exchange circuit Reduce. Although the flow rate of the refrigerant Rf in the condensing circuit 40 and the evaporation circuit 30 decreases, the flow rate of the refrigerant Rf flowing through the heat exchange circuit can be maintained high because the flow rate of the refrigerant Rf discharged from the compressor 10 is high.

  On the other hand, when the compressor 10 is operated at a small operating capacity (low rotational speed), the control device 50 connects the first condenser 42a and the second condenser 42b of the condensation circuit 40 and the first evaporation of the evaporation circuit 30. The connection between the evaporator 32a and the second evaporator 32b is switched in series. Specifically, the control device 50 closes both the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40, and closes both the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the evaporation circuit 30. Thus, the connection of the first condenser 42a and the second condenser 42b of the condenser circuit 40 and the connection of the first evaporator 32a and the second evaporator 32b of the evaporator circuit 30 are both switched in series. In this state, the flow rate of the refrigerant Rf flowing through the heat exchange circuit is increased.

  As described above, the control device 50 of the refrigeration apparatus 1 according to the present embodiment is configured so that the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40 and the third of the evaporation circuit 30 correspond to the operating capacity of the compressor 10. The refrigerating apparatus 1 is controlled so as to switch the opening and closing of the electromagnetic valve 35a and the fourth electromagnetic valve 35b so that the flow rate of the refrigerant Rf in the heat exchange circuit is suitably kept high and the heat exchange efficiency of the heat exchange circuit is improved.

  The first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40 and the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the evaporation circuit 30 are opened and closed so that the first condenser 42a and the second condenser 42b are opened and closed. And a switching mechanism for switching the connection between the first evaporator 32a and the second evaporator 32b in series or in parallel. Hereinafter, the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40 and the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the evaporation circuit 30 may be collectively referred to as a switching mechanism.

  When the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40 and the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the evaporation circuit 30 are all opened, the connection between the first condenser 42a and the second condenser 42b. Since the connection between the first evaporator 32a and the second evaporator 32b is switched in parallel, the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensation circuit 40, the third electromagnetic valve 35a and the fourth electromagnetic valve of the evaporation circuit 30 are switched. A state in which all of the electromagnetic valves 35b are opened is referred to as a parallel state of the switching mechanism.

  When the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40 and the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the evaporation circuit 30 are all closed, the first condenser 42a and the second condenser 42b. And the connection of the first evaporator 32a and the second evaporator 32b are switched in series, so that the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40, the third electromagnetic valve 35a of the evaporation circuit 30 and A state where all the fourth electromagnetic valves 35b are closed is referred to as a serial state of the switching mechanism.

  In other words, the first solenoid valve 45a and the second solenoid valve 45b are arranged such that the refrigerant Rf flows through the first condensation pipe 43a and the second condensation pipe 43b when the switching mechanism is in the parallel state. The second condensing pipe 43b is opened, and the third electromagnetic valve 35a and the fourth electromagnetic valve 35b are arranged so that the refrigerant Rf flows through the first evaporation pipe 33a and the second evaporation pipe 33b when the switching mechanism is in the parallel state. The evaporation pipe 33a and the second evaporation pipe 33b are opened.

  The first solenoid valve 45a and the second solenoid valve 45b shut off the first condensing pipe 43a and the second condensing pipe 43b so that the refrigerant Rf flows through the bypass pipe 44 when the switching mechanism is in series. The third solenoid valve 35a and the fourth solenoid valve 35b block the first evaporation pipe 33a and the second evaporation pipe 33b so that the refrigerant Rf flows through the bypass pipe 34 when the switching mechanism is in a series state.

  The check valve 46 is a valve that prevents the refrigerant Rf from flowing through the bypass pipe 44 when the switching mechanism is in the parallel state. The check valve 36 bypasses the refrigerant Rf when the switching mechanism is in the parallel state. This is a valve that prevents the pipe 34 from flowing.

  With reference to FIG. 4, the procedure in which the control apparatus 50 controls the refrigerating apparatus 1 will be described (see FIGS. 1 to 3 as appropriate). The control device 50 operates the compressor 10 with an operation capacity corresponding to the water temperature measured by the water temperature gauge 31a (step S1). The operating capacity of the compressor 10 is preferably determined according to the water temperature measured by the water temperature gauge 31a. Therefore, for example, a configuration in which a map indicating the relationship between the water temperature measured by the water temperature gauge 31a and the operating capacity of the compressor 10 is stored in a storage unit (not shown) of the control device 50 is preferable. The control device 50 is measured by the water temperature gauge 31a. The operating capacity of the compressor 10 is determined with reference to the map based on the water temperature to be performed.

  Furthermore, the control device 50 determines the rotational speed of the compressor 10 so as to achieve the determined operating capacity, and operates the compressor 10 at the determined rotational speed. Specifically, the control device 50 transmits a control signal to the compressor 10 so as to achieve the determined rotation speed.

And the control apparatus 50 determines whether the determined operating capacity is larger than the predetermined value set beforehand (step S2). In step S <b> 2, the control device 50 determines the magnitude of the operation capacity based on, for example, the rotation speed of the compressor 10.
As described above, since the rotational speed of the compressor 10 and the operating capacity have a positive correlation, the control device 50, for example, when the determined rotational speed of the compressor 10 is higher than a predetermined rotational speed threshold, When it is determined that the operating capacity of the compressor 10 is larger than a predetermined value set in advance and the rotational speed of the compressor 10 is lower than a predetermined rotational speed threshold, the operating capacity of the compressor 10 is smaller than a predetermined value set in advance Is determined.

The predetermined rotation speed threshold value may be set as appropriate.
For example, even when the switching mechanism is in a series state, the first condenser 42a and the second condenser 42b are connected in series, and the first evaporator 32a and the second evaporator 32b are connected in series, What is necessary is just to set the rotational speed corresponding to the upper limit of the operating capacity of the compressor 10 which can obtain the flow rate of the refrigerant | coolant Rf which can exchange heat efficiently with an exchange circuit to a predetermined rotational speed threshold value.

When the determined operating capacity is larger than a predetermined value set in advance (step S2 → Yes), the control device 50 determines that all the electromagnetic valves, that is, the first electromagnetic valve 45a and the second electromagnetic valve 45b of the condensing circuit 40, All of the third electromagnetic valve 35a and the fourth electromagnetic valve 35b of the evaporation circuit 30 are opened (step S3), and the switching mechanism is switched to the parallel state.
On the other hand, when the determined operating capacity is smaller than a predetermined value set in advance (step S2 → No), the control device 50 closes all the electromagnetic valves (step S4), and switches the switching mechanism to the serial state.

  And the control apparatus 40 always monitors the water temperature which the water thermometer 31a measures, determines the operating capacity of the compressor 10 according to the water temperature, and switches the parallel state and serial state of a switching mechanism based on the determined operating capacity. .

  As described above, the control device 50 of the refrigeration apparatus 1 according to the present embodiment shown in FIG. 1 determines the operating capacity of the compressor 10 based on the water temperature of the water to be cooled Wt2 measured by the water temperature gauge 31a. 10 is further operated, and the refrigeration apparatus 1 is controlled so that the efficiency of heat exchange in the heat exchange circuit is improved by appropriately switching the parallel state and the serial state of the switching mechanism based on the operation capacity of the compressor 10.

  Since the flow rate of the refrigerant Rf flowing through the refrigerant circuit changes according to the change in the operating capacity of the compressor 10, the present embodiment for switching the parallel state and the serial state of the switching mechanism according to the operating capacity of the compressor 10 The parallel state and the serial state of the switching mechanism can be switched according to the flow rate of the refrigerant Rf flowing through the heat exchange circuit. And the efficiency of the heat exchange in a heat exchange circuit can be improved suitably.

  That is, when the water temperature of the to-be-cooled water Wt2 greatly deviates from the target temperature, such as in the early stage of freezing, the control device 50 operates the compressor 10 with a large operating capacity and switches the switching mechanism to the parallel state. The first condenser 42a and the second condenser 42b are connected in parallel, and the first evaporator 32a and the second evaporator 32b are connected in parallel to reduce the pressure loss in the heat exchange circuit of the high flow rate refrigerant Rf. The heat exchange efficiency in the heat exchange circuit can be improved.

  Moreover, when the water temperature of the to-be-cooled water Wt2 is close to the target temperature, the control device 50 operates the compressor 10 with a small operation capacity and switches the switching mechanism to the serial state. The first condenser 42a and the second condenser 42b are connected in series, and the first evaporator 32a and the second evaporator 32b are connected in series, so that the flow rate of the refrigerant Rf in the heat exchange circuit can be kept high. The heat exchange efficiency in the heat exchange circuit can be improved.

Note that the design of this embodiment can be changed as appropriate without departing from the spirit of the invention.
For example, as shown in FIG. 5A, the check valve 46 (see FIG. 1) and the first electromagnetic valve 45a (see FIG. 1) of the bypass pipe 44 of the condensing circuit 40 are not provided, but the first condensing pipe 43a. A three-way valve 47 controlled by the control device 50 may be provided at a branch point 44a (see FIG. 1) of the bypass pipe 44.

  The three-way valve 47 includes three connection ports 47a to 47c, and a state A in which the connection port 47a and the connection port 47b communicate with each other and the connection port 47c is closed by the operation of a valve body (not shown), The connection port 47b can be switched to the closed state B. In the three-way valve 47, the bypass pipe 44 is connected to the connection port 47b, the first condenser 42a side of the first condensing pipe 43a is connected to the connection port 47a, and the confluence 40b side of the first condensing pipe 43a is connected to the connection port 47c. Provided to be connected to.

When the first condenser 42a and the second condenser 42b are connected in series, the control device 50 switches the three-way valve 47 to the state A and closes the second electromagnetic valve 45b.
The refrigerant Rf flowing into the condensing circuit 40 from the refrigerant pipe 1a via the branch point 40a flows in the order of the first condensing pipe 43a, the first condenser 42a, and the connection port 47a of the three-way valve 47, and from the connection port 47b to the bypass pipe 44. Flow into. The refrigerant Rf flows out of the condensing circuit 40 through the second condenser 42b, the second condensing pipe 43b, and the confluence 40b after flowing through the branch point 44b.

On the other hand, when the first condenser 42a and the second condenser 42b are connected in parallel, the control device 50 switches the three-way valve 47 to the state B and opens the second electromagnetic valve 45b.
The refrigerant Rf flowing into the condensing circuit 40 from the refrigerant pipe 1a branches at the branch point 40a and flows through both the first condensing pipe 43a and the second condensing pipe 43b. The refrigerant Rf flowing through the first condenser tube 43a flows in the order of the first condenser 42a and the connection port 47a of the three-way valve 47, and reaches the junction 40b from the connection port 47c via the first condensation tube 43a.

  The refrigerant Rf branched at the branch point 40a and flowing through the second condensing pipe 43b flows in the order of the branch point 44b and the second condenser 42b and reaches the confluence 40b. And the refrigerant | coolant Rf which flows through the 1st condensation pipe | tube 43a, and the refrigerant | coolant Rf which flows through the 2nd condensation pipe | tube 43b merge at the junction 40b, and flow out from the condensation circuit 40. FIG.

  As described above, even when the three-way valve 47 is provided as shown in FIG. 5A, the connection between the first condenser 42a and the second condenser 42b in the condensation circuit 40 can be switched in series or in parallel.

  In addition, according to this structure, the switching mechanism which can switch a parallel state and a serial state including the three-way valve 47 is comprised. In this case, the state where the three-way valve 47 is switched to the state A and the second electromagnetic valve 45b is closed is the series state of the switching mechanism, the three-way valve 47 is switched to the state B and the second electromagnetic valve 45b is opened. Is the parallel state of the switching mechanism. That is, when the switching mechanism is in a series state, the three-way valve 47 is switched to a state (state A) in which the refrigerant Rf flows through the bypass pipe 44, and when the switching mechanism is in a parallel state, the three-way valve 47 is in a state where the refrigerant Rf does not flow through the bypass pipe 44. Switch to (State B). And the check valve 46 (refer FIG. 1) becomes unnecessary.

  Further, the check valve 46 and the second electromagnetic valve 45b of the condensing circuit 40 shown in FIG. 1 are not provided, but a three-way valve controlled by the control device 50 is provided at the branch point 44b of the second condensing pipe 43b and the bypass pipe 44. It is good also as a structure. Further, similarly to the condensation circuit 40, the evaporation circuit 30 (see FIG. 1) may be provided with a three-way valve.

In the present embodiment, the condenser circuit 40 includes two condensers 42 a and 42 b as shown in FIG. 1, but a condensing circuit including three or more condensers 42 may be used.
As shown in FIG. 5B, in the case of the condensing circuit 40 including three condensers 42a, 42b, and 42c, the refrigerant pipe 1a is a branch point 40a and is added to the first condensing pipe 43a and the second condensing pipe 43b. The first condensing tube 43a, the second condensing tube 43b, and the third condensing tube 43c merge at the confluence 40b. The condensing circuit 40 includes a third condenser 42c connected to the third condensing pipe 43c. That is, the first condensing pipe 43a to the third condensing pipe 43c are arranged in parallel to the flow of the refrigerant Rf.
In FIG. 5B, the same elements as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted as appropriate.

The upstream side of the third condenser 42c and the downstream side of the first condenser 42a are connected by a bypass pipe 441 where the third condenser pipe 43c and the first condenser pipe 43a branch at the respective branch points 44c and 44a. 441 includes a check valve 461.
The check valve 461 changes the flow direction of the refrigerant Rf in the bypass pipe 441 in one direction from the downstream side of the first condenser 42a to the upstream side of the third condenser 42c, that is, from the branch point 44a to the branch point 44c. This is a valve that restricts the refrigerant Rf from flowing from the upstream side of the third condenser 42c to the downstream side of the first condenser 42a.

Further, the upstream side of the second condenser 42b and the downstream side of the third condenser 42c are connected by a bypass pipe 442 where the second condenser pipe 43b and the third condenser pipe 43c branch at respective branch points 44b and 44d, The bypass pipe 442 is provided with a check valve 462.
The check valve 462 changes the flow direction of the refrigerant Rf in the bypass pipe 442 in one direction from the downstream side of the third condenser 42c to the upstream side of the second condenser 42b, that is, from the branch point 44d to the branch point 44b. This is a valve that restricts the refrigerant Rf from flowing from the upstream side of the second condenser 42b to the downstream side of the third condenser 42c.

  In addition, a sixth electromagnetic valve 45d, which is an on-off valve that opens and closes the third condenser pipe 43c, is provided on the downstream side of the third condenser 42c between the junction 40b and the branch point 44d, and upstream of the third condenser 42c. The fifth solenoid valve 45c, which is an on-off valve that opens and closes the third condensing pipe 43c, is provided between the branch point 40a and the branch point 44c.

When the first solenoid valve 45a, the second solenoid valve 45b, the fifth solenoid valve 45c, and the sixth solenoid valve 45d are all opened, the first condenser 42a to the third condenser 42c are connected in parallel, and the first When the solenoid valve 45a, the second solenoid valve 45b, the fifth solenoid valve 45c, and the sixth solenoid valve 45d are all closed, the first condenser 42a to the third condenser 42c are connected in series.
According to this structure, the switching mechanism which can switch a parallel state and a serial state is comprised including the 5th solenoid valve 45c and the 6th solenoid valve 45d in addition to the 1st solenoid valve 45a and the 2nd solenoid valve 45b.
In this case, the state where all of the first solenoid valve 45a, the second solenoid valve 45b, the fifth solenoid valve 45c, and the sixth solenoid valve 45d are closed is the series state of the switching mechanism, and the first solenoid valve 45a and the second solenoid valve 45 The state in which all of the valve 45b, the fifth electromagnetic valve 45c, and the sixth electromagnetic valve 45d are opened is the parallel state of the switching mechanism.

  Thus, the condensing circuit 40 provided with the three condensers 42 (the 1st condenser 42a-the 3rd condenser 42c) may be sufficient. Further, a configuration equivalent to the configuration including the third condenser pipe 43c, the third condenser 42c, the fifth electromagnetic valve 45c, and the sixth electromagnetic valve 45d shown in FIG. 5B is added, and a bypass pipe and a check valve are added. Is provided as appropriate, so that the condensing circuit 40 including three or more condensers 42 can be configured.

  Further, although not shown, an evaporation circuit 30 (see FIG. 1) including three or more evaporators 32 can be similarly configured.

  Further, for example, as shown in FIG. 6, instead of the first condenser 42a and the second condenser 42b of FIG. 1, a heat exchange module having a first heat exchange part 420a and a second heat exchange part 420b therein. The condensation circuit 40 including the condenser 420 may be used. The first heat exchanging part 420a is configured to exchange heat between the refrigerant Rf flowing through the first refrigerant path 421a and the refrigerant cooling water Wt1 flowing through the water pipe 41, and the second heat exchanging part 420b passes through the second refrigerant path 421b. The refrigerant Rf flowing and the refrigerant cooling water Wt1 flowing through the water pipe 41 are configured to exchange heat.

  The first refrigerant path 421a is connected to the first condensing pipe 43a, and the second refrigerant path 421b is connected to the second condensing pipe 43b. Further, the bypass pipe 44 includes a branch point 44a formed in the first condensing pipe 43a on the downstream side of the first refrigerant path 421a and a branch point 44b formed on the second condensing pipe 43b on the upstream side of the second refrigerant path 421b. The bypass pipe 44 is provided with a check valve 46, and the first electromagnetic valve 45a and the second electromagnetic valve 45b are disposed in the same manner as the condensation circuit 40 shown in FIG. The check valve 46 regulates the flow direction of the refrigerant Rf so that it flows from the branch point 44a side to the branch point 44b side.

  In the condensing circuit 40 configured in this way, the first heat exchanging section 420a and the second heat exchanging section 420b are arranged in parallel with the flow of the refrigerant Rf, and further arranged in series via the bypass pipe 44. Is done. When both the first electromagnetic valve 45a and the second electromagnetic valve 45b are opened, the refrigerant Rf flows in parallel through the first heat exchange unit 420a and the second heat exchange unit 420b, and the first electromagnetic valve 45a and the second electromagnetic valve 45b. When both are closed, the refrigerant Rf flows from the first heat exchange section 420a to the second heat exchange section 420b. That is, the refrigerant Rf flows in series through the first heat exchange unit 420a and the second heat exchange unit 420b.

Therefore, even if it is the condensation circuit 40 comprised as shown in FIG. 6, as shown in FIG. 1, the effect equivalent to the condensation circuit 40 provided with the 1st condenser 42a and the 2nd condenser 42b can be acquired. .
Moreover, as shown to (a) of FIG. 5, it can replace with the 1st solenoid valve 45a, and the structure provided with the three-way valve 47 is also possible.

  Although not shown, it is also possible to use a condenser composed of a heat exchange module having three heat exchange units. In this case, for example, by replacing the three condensers 42a, 42b, and 42c of the condensing circuit 40 shown in FIG. 5B with three heat exchange units, the condensing circuit 40 shown in FIG. 5B is connected. The same effect can be obtained. Furthermore, it is possible to use a condenser comprising a heat exchange module having three or more heat exchange units.

  Further, although not shown, the evaporator circuit 30 (see FIG. 1) is provided with an evaporator composed of a heat exchange module having two heat exchange units, and, similarly to the evaporator circuit 30 shown in FIG. It is possible to configure the evaporation circuit 30 by disposing the stop valve 36, the third electromagnetic valve 35a, and the fourth electromagnetic valve 35b, and use an evaporator including a heat exchange module having two or more heat exchange units. It is also possible to configure the evaporation circuit 30.

In addition, for example, a rotation speed meter (not shown) that measures the rotation speed of the compressor 10 (see FIG. 1) is provided, and the control device 50 (see FIG. 1) has the switching mechanism in parallel according to the rotation speed of the compressor 10. It is good also as a structure which switches a serial state.
For example, in step S2 of FIG. 4, the rotation speed of the compressor 10 is compared with the predetermined rotation speed threshold, and when the rotation speed of the compressor 10 is higher than the predetermined rotation speed threshold, step S3 is executed. You may comprise so that step S4 may be performed when the rotational speed of the compressor 10 is lower than a predetermined rotational speed threshold value.

Moreover, the flowmeter of the refrigerant | coolant Rf discharged from the compressor 10 (refer FIG. 1) is provided, and the control apparatus 50 (refer FIG. 1) is a parallel state of the switching mechanism according to the flow velocity of the refrigerant | coolant Rf. It is good also as a structure which switches a serial state.
For example, in step S2 of FIG. 4, when the flow rate of the refrigerant Rf discharged from the compressor 10 is higher than a predetermined flow rate threshold value, step S3 is executed, and the flow rate of the refrigerant Rf discharged from the compressor 10 is set to the predetermined flow rate threshold value. You may comprise so that step S4 may be performed when it is lower.
The flow rate threshold value in this case may be, for example, the flow rate of the refrigerant Rf that is discharged when the compressor 10 operates at the above-described rotation speed threshold value.

1 Refrigeration equipment 1a Refrigerant piping (pipe)
DESCRIPTION OF SYMBOLS 10 Compressor 20 Expansion valve 32 Evaporator 32a 1st evaporator 32b 2nd evaporator 33a 1st evaporation pipe (diversion pipe)
33b Second evaporation pipe (diversion pipe)
34, 44, 441, 442 Bypass pipe 35a Third solenoid valve (open / close valve, switching mechanism)
35b Fourth solenoid valve (open / close valve, switching mechanism)
36, 46, 461, 462 Check valve 42 Condenser 42a First condenser 42b Second condenser 43a First condensing pipe (dividing pipe)
43b Second condensing pipe (split pipe)
43c 3rd condensing pipe (diversion pipe)
45a First solenoid valve (open / close valve, switching mechanism)
45b Second solenoid valve (open / close valve, switching mechanism)
45c Fifth solenoid valve (open / close valve, switching mechanism)
45d Sixth solenoid valve (open / close valve, switching mechanism)
47 Three-way valve (switching mechanism)
60 Laminated plate heat exchanger 70 Shell and tube heat exchanger 420 Condenser (heat exchange module)
420a First heat exchange section 420b Second heat exchange section 421a First refrigerant path 421b Second refrigerant path

Claims (8)

A refrigeration apparatus including a refrigerant circuit in which a compressor having a variable operating capacity, a plurality of condensers, an expansion valve, and a plurality of evaporators are connected by a refrigerant flow line,
A series state in which the plurality of condensers are connected in series to the refrigerant flow and the evaporators are connected in series to the refrigerant flow;
A switching mechanism for switching between the plurality of condensers in parallel with the refrigerant flow and the parallel state in which the evaporators are connected in parallel with the refrigerant flow;
The refrigeration apparatus characterized by switching the series state and the parallel state of the switching mechanism according to the operating capacity of the compressor. The switching mechanism is
When the operating capacity of the compressor is larger than a predetermined value, it is switched to the parallel state,
The refrigeration apparatus according to claim 1, wherein when the operating capacity of the compressor is equal to or less than a predetermined value, the compressor is switched to the serial state.   The refrigeration apparatus according to claim 1 or 2, wherein the compressor is capable of controlling the operating capacity by controlling a frequency of an alternating current generated by an inverter circuit. Each of the plurality of condensers and the plurality of evaporators is connected to a plurality of shunt pipes that are branched in parallel with the flow of the refrigerant and arranged in parallel. The heat exchanger comprises a plurality of heat exchangers arranged in series from upstream to downstream of the refrigerant flow via a bypass pipe connecting the branch pipes.
The switching mechanism is
An on-off valve that shuts off the branch pipe so that the refrigerant flows through the bypass pipe when in the series state and opens the branch pipe so that the refrigerant flows through the branch pipe when in the parallel state. Configured,
The refrigeration apparatus according to any one of claims 1 to 3, further comprising a check valve that prevents the refrigerant from flowing through the bypass pipe when the switching mechanism is in the parallel state. The switching mechanism is
It is configured to include a three-way valve that switches to a state in which the refrigerant flows through the bypass pipe in the series state, and switches to a state in which the refrigerant does not flow through the bypass pipe in the parallel state.
The refrigeration apparatus according to claim 4, wherein the check valve is unnecessary.   The refrigeration apparatus according to claim 4 or 5, wherein at least one of the plurality of heat exchangers is a laminated plate heat exchanger.   The refrigeration apparatus according to any one of claims 4 to 6, wherein at least one of the plurality of heat exchangers is a shell-and-tube heat exchanger. At least one of a heat exchange module including a plurality of heat exchange units to be the plurality of condensers and a heat exchange module including a plurality of heat exchange units to be the plurality of evaporators is the plurality of heat exchangers. Instead,
The plurality of heat exchange units are
5. The apparatus according to claim 4, wherein the plurality of flow dividing pipes are connected one by one and arranged in parallel, and arranged in series from upstream to downstream of the flow of the refrigerant through the bypass pipe. Item 6. The refrigeration apparatus according to Item 5.

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