WO2013151005A1

WO2013151005A1 - Composite dual refrigeration cycle device

Info

Publication number: WO2013151005A1
Application number: PCT/JP2013/059912
Authority: WO
Inventors: 英樹丹野; 山本　学; 森田　健
Original assignee: 東芝キヤリア株式会社
Priority date: 2012-04-04
Filing date: 2013-04-01
Publication date: 2013-10-10
Also published as: CN104204693A; JPWO2013151005A1; JP5830602B2; CN104204693B

Abstract

Provided is a composite dual refrigeration cycle device provided with: two high-temperature side refrigeration circuits respectively having water/refrigerant heat exchangers for heat exchange of water and a refrigerant discharged from a compressor on the high-temperature side, and two low-temperature side refrigeration circuits respectively having evaporators comprising air heat exchangers having blower fans, the circuits being built into the same chassis; and with hot water lines configured to permit heat exchange from the respective high-temperature side refrigeration circuits to the respective low-temperature side refrigeration circuits by a cascade heat exchanger, for circulating cold water or hot water to the cold water-side flow channel of the water/refrigerant heat exchangers of the high-temperature side refrigeration circuits, the interior of the chassis being furnished with a control device for overall control of operation of the device. The composite dual refrigeration cycle device is characterized in that the device is configured such that the two low-temperature side refrigeration circuits are connected to the control device, and when one of the low-temperature side refrigeration circuits performs a defrosting operation of the evaporator thereof, the other low-temperature side refrigeration circuit is controlled so as to perform heat exchange with the cascade heat exchanger, while the rotation speed of the blower fan of the other low-temperature side refrigeration circuit is controlled to a rotation speed higher than the rotation speed of the blower fan during a heating operation of both of the low-temperature side refrigeration circuits together.

Description

Combined dual refrigeration cycle equipment

The present invention relates to a composite binary refrigeration cycle apparatus when two binary refrigeration cycles are juxtaposed.

Conventionally, as this type of dual refrigeration cycle apparatus, cascade heat exchange is performed between a high-temperature side refrigeration circuit that heats water flowing through a hot-water pipe or hot water, and a low-temperature side refrigeration circuit that heats a high-temperature side refrigerant circulating in the high-temperature side refrigeration circuit It is known that a two-stage refrigeration cycle is configured by connecting in a heat exchangeable manner through a container and accommodated in one housing (see, for example, Patent Document 1).

JP 2007-198693 A

In recent years, in order to warm hot water with higher efficiency, a composite binary refrigeration cycle apparatus in which two binary refrigeration cycle apparatuses are connected in series or in parallel to a hot water pipe is being provided.

In this composite binary refrigeration cycle apparatus, an air heat exchanger is used as an evaporator in the low temperature side refrigeration circuit, and the refrigerant introduced here evaporates by exchanging heat with the outside air. For this reason, when the outside air temperature becomes extremely low, the moisture contained in the outside air freezes to become frost and adheres as it is.

¡Defrosting is necessary because the heat exchange efficiency decreases when the air heat exchanger is frosted. For this purpose, the defrosting method includes a reverse cycle defrosting method in which the four-way valves of the high-temperature side refrigerant circuit and the low-temperature side refrigeration circuit are switched to reverse the refrigerant circulation direction, or the high-temperature discharge of the compressor of the low-temperature side refrigeration circuit A hot gas defrosting system in which the refrigerant is bypassed through the cascade heat exchanger and directly led to the evaporator can be considered.

However, in the case of the reverse cycle defrosting method, there is a merit that the defrosting can be completed in a short time because hot water on the use side is used as a heat source, but there is a problem that the hot water outlet temperature is lower than the inlet temperature. is there. In addition, in the case of the hot gas defrosting method, there are no problems with the reverse cycle defrosting method of the above operation, but because the heat source necessary for defrosting is insufficient, the defrosting time is increased and hot water is added as a result. There is a problem that the time that cannot be heated increases.

Therefore, in view of the above-described problems of the prior art, the object of the present invention is to maintain the simplification of the configuration even if two binary refrigeration cycles are provided, and to reduce the temperature of water flowing through the hot water piping or hot water as much as possible. An object of the present invention is to provide a composite dual refrigeration cycle apparatus that can supply hot water without defrosting in a short time.

The composite dual refrigeration cycle apparatus that is one embodiment of the present invention provided to achieve the above object includes a water / refrigerant heat exchanger that exchanges heat between the refrigerant discharged from the high-temperature side compressor and water. Two high temperature side refrigeration circuits and two low temperature side refrigeration circuits each having an evaporator composed of an air heat exchanger having a blower fan are mounted in the same housing, and each of the high temperature side refrigeration circuits is cascade heat exchange. And a hot water pipe configured to circulate water or hot water in the water-side flow path of the water / refrigerant heat exchanger of the high-temperature side refrigeration circuit. A composite dual refrigeration cycle apparatus provided with a control device for controlling the overall operation of the apparatus in the body, wherein the two low temperature side refrigeration circuits are connected to the control device, and one of the low temperature side refrigeration circuits When performing the defrosting operation of the evaporator, the other low-temperature side refrigeration circuit is controlled to radiate heat by the cascade heat exchanger, and the rotation speed of the blower fan of the other low-temperature side refrigeration circuit is adjusted to both It is configured to control the rotational speed to be higher than the rotational speed of the blower fan when the low temperature side refrigeration circuit is heated together.

Further, in the composite binary refrigeration cycle apparatus, each of the cascade heat exchangers includes a high-temperature refrigerant channel communicating with the high-temperature side refrigeration circuit, a first low-temperature refrigerant channel communicating with one of the low-temperature side refrigeration circuits, A second low-temperature refrigerant flow path communicating with the other low-temperature side refrigeration circuit is provided, the first low-temperature refrigerant flow paths and the second refrigerant flow paths are connected in series, respectively, and the high-temperature refrigerant flow It is preferable that the first low-temperature refrigerant flow path is disposed on one surface side of the path and the plate-type heat exchanger is disposed on the other surface side with the second low-temperature refrigerant flow path.

According to the embodiment of the present invention having the above-described features, the problem of the above-described prior art can be solved, and even if two binary refrigeration cycles are provided, the simplification of the configuration can be maintained and the water flowing through the hot water pipe can be maintained. Alternatively, it is possible to provide a combined dual refrigeration cycle apparatus that can supply hot water without lowering the temperature of hot water as much as possible and defrost in a short time. Further detailed effects are described collectively at the end of this specification.

The refrigeration cycle block diagram of the composite binary refrigeration cycle apparatus which concerns on one Embodiment of this invention. The schematic block diagram of the cascade heat exchanger shown in FIG. FIG. 2 is an external perspective view of the composite binary refrigeration cycle apparatus shown in FIG. 1. FIG. 4 is an external front view of the composite binary refrigeration cycle apparatus shown in FIG. 3. The external appearance side view of the composite binary refrigerating-cycle apparatus shown in FIG. FIG. 4 is an external perspective view of a composite dual refrigeration cycle apparatus when an optional device is accommodated in the partition wall shown in FIG. 3. The external appearance perspective view which shows the state which removed the outer cover of the partition part of the composite binary refrigeration cycle apparatus shown in FIG. The external appearance front view of the composite binary refrigeration cycle apparatus shown in FIG.

Hereinafter, the present embodiment will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or an equivalent part in several drawing.

FIG. 1 is a refrigeration cycle configuration diagram of a composite dual refrigeration cycle apparatus according to an embodiment used as a hot water supply system, for example.

As shown in FIG. 1, the composite binary refrigeration cycle apparatus has a first high-temperature side refrigeration in which, for example, R134a is circulated as a refrigerant in one housing K, hot water piping H that circulates water or hot water as a heat medium. The circuit R1a and the second high temperature side refrigeration circuit R1b, the first low temperature side refrigeration circuit R2a and the second low temperature side refrigeration circuit R2b that circulate, for example, R410A as a refrigerant, and the control device C are accommodated.

The hot water pipe H has one end connected to a water supply source, a hot water storage tank, and the like, and the other end connected to a hot water storage side such as a hot water storage tank, a hot water tap.

A pump 1 is connected to the hot water pipe H, and the water side flow path 3a of the first water / refrigerant heat exchanger 2A in the first high temperature side refrigeration circuit R1a with a predetermined interval on the downstream side thereof, The water side flow path 3b of the second water / refrigerant heat exchanger 2B in the second high temperature side refrigeration circuit R1b is connected.

The first high temperature side refrigeration circuit R1a includes a discharge portion of the high temperature side compressor 5, the refrigerant side flow path 6 in the first water / heat exchanger 2A, the high temperature side receiver 7, the high temperature side expansion device 8, and the first. The high-temperature refrigerant flow path 10 of the cascade heat exchanger 9 and the suction part of the high-temperature side compressor 5 are sequentially connected by a refrigerant pipe P.

The second high temperature side refrigeration circuit R1b includes a discharge portion of the high temperature side compressor 11, the refrigerant side flow path 12, the high temperature side receiver 13, the high temperature side expansion device 14, the second water / heat exchanger 2B. The high-temperature refrigerant flow path 16 of the cascade heat exchanger 15 and the suction portion of the high-temperature side compressor 11 are sequentially connected by the refrigerant pipe P.

1st low temperature side freezing circuit R2a has connected the discharge part of the low temperature side compressor 18 to the 1st port P1 of the four-way valve 19 through the refrigerant pipe P. As shown in FIG. The four-way valve 19 connects the second port P2 to the first low-temperature refrigerant flow path 33 of the second cascade heat exchanger 15, and the third port P3 is a first evaporator that is a first evaporator. Are connected to the air heat exchanger 21 via refrigerant pipes P, respectively.

Further, the four-way valve 19 has its fourth port P4 connected to the suction portion of the low-temperature side compressor 18 through the accumulator 22 in series by the refrigerant pipe P.

The first low-temperature refrigerant flow path 33 in the second cascade heat exchanger 15 is connected in series to the first low-temperature refrigerant flow path 20 in the first cascade heat exchanger 9 by the refrigerant pipe P. Further, the first low-temperature refrigerant flow path 20 in the first cascade heat exchanger 9 is sequentially connected to the low-temperature side receiver 23, the low-temperature side expansion device 24, and the air heat exchanger 21 by the refrigerant pipe P. A first blower fan FA is disposed opposite to the air heat exchanger 21.

2nd low temperature side freezing circuit R2b has connected the discharge part of the low temperature side compressor 25 to the 1st port P1 of the four-way valve 26 via the refrigerant pipe P. As shown in FIG. The four-way valve 26 connects the second port P2 to the second low-temperature refrigerant flow path 27 in the second cascade heat exchanger 15, and the third port P3 is a second evaporator that is a second evaporator. Are connected to the air heat exchanger 28 via refrigerant pipes P, respectively.

Further, the four-way valve 26 has its fourth port connected to the suction portion of the low temperature side compressor 25 via the accumulator 29 in series by the refrigerant pipe P.

The second low-temperature refrigerant flow path 27 in the second cascade heat exchanger 15 is connected in series to the second low-temperature refrigerant flow path 34 in the first cascade heat exchanger 9 by the refrigerant pipe P. .

Further, the second low-temperature refrigerant flow path 34 in the first cascade heat exchanger 9 is connected to the low-temperature side receiver 30, the low-temperature side expansion device 31, and the air heat exchanger 28 in the second low-temperature refrigeration circuit R 2 b. The pipes P are sequentially connected. A blower fan FB is disposed opposite to the air heat exchanger 28.

FIG. 2 shows the configuration of the first cascade heat exchanger 9. Since the configuration of the first cascade heat exchanger 9 is the same as that of the second cascade heat exchanger 15, the latter description is omitted below.

The first cascade heat exchanger 9 is provided on one side surface of the housing 40 at an end portion where the high-temperature refrigerant inlet 40a and the high-temperature refrigerant outlet 40b are separated from each other in the height direction. A refrigerant pipe P communicating with the high temperature side expansion device 8 is connected to the high temperature refrigerant introduction port 40a, and a refrigerant pipe P communicating with the suction portion of the high temperature side compressor 5 is connected to the high temperature refrigerant outlet port 40b.

The housing 40 accommodates the high-temperature refrigerant flow path 10 therein. The high-temperature refrigerant flow path 10 is connected to the high-temperature refrigerant inlet 40a and the high-temperature refrigerant outlet 40b, and is paired with a pair of upper and lower

main flow paths

41a and 41a parallel to each other and closed at opposite ends, and the

main flow paths

41a, 41a, and a plurality of high-temperature refrigerant branch passages 41b parallel to each other at a predetermined interval in the horizontal direction in the figure.

The housing 40 is provided with a first low-temperature refrigerant inlet 42a and a second low-temperature refrigerant inlet 43a on the other side surfaces at positions adjacent to each other. Furthermore, a first low-temperature refrigerant outlet 42 b and a second low-temperature refrigerant outlet 43 b are provided at positions adjacent to each other at positions separated on the same side surface of the housing 40.

A refrigerant pipe P communicating with the first low-temperature refrigerant flow path 33 of the second cascade heat exchanger 15 is connected to the first low-temperature refrigerant inlet 42a, and the first low-temperature refrigerant outlet 42b is connected to the first low-temperature refrigerant outlet 42b. A refrigerant pipe P communicating with the low-temperature receiver 23 in the one low-temperature refrigeration circuit R2a is connected.

A refrigerant pipe P communicating with the second low-temperature refrigerant flow path 27 of the second cascade heat exchanger 15 is connected to the second low-temperature refrigerant inlet 43a, and a second low-temperature refrigerant outlet 43b is connected to the second low-temperature refrigerant outlet 43b. A refrigerant pipe P communicating with the low-temperature receiver 30 in the second low-temperature refrigeration circuit R2b is connected.

The housing 40 includes a first low-temperature refrigerant flow path 20 that communicates with the first low-temperature refrigerant inlet 42a and the first low-temperature refrigerant outlet 42b. Furthermore, a second low-temperature refrigerant flow path 34 communicating with the second low-temperature refrigerant inlet 43a and the second low-temperature refrigerant outlet 43b is formed in the housing 40.

The first low-temperature refrigerant flow path 20 is connected to the first low-temperature refrigerant inlet port 42a and the first low-temperature refrigerant outlet port 42b, and is parallel to each other and closed at opposite ends in the figure. 44a, and a plurality of first low-temperature refrigerant branch flow paths 44b that communicate with each other between the pair of

main flow paths

44a and 44a and are parallel to each other at a predetermined interval.

The second low-temperature refrigerant channel 34 is connected to the second low-temperature refrigerant inlet 43a and the second low-temperature refrigerant outlet 43b, and is parallel to each other and closed between the main channel 45a and the main channel 45a. And a plurality of second low-temperature refrigerant branch flow paths 45b that are parallel to each other at a predetermined interval.

That is, in the housing 40, the high-temperature refrigerant branch channel 41 b that constitutes the high-temperature refrigerant channel 10, the first low-temperature refrigerant branch channel 44 b that constitutes the first low-temperature refrigerant channel 20, and the second low-temperature refrigerant. The second low-temperature refrigerant branch flow paths 45b constituting the flow path 34 are provided in parallel at a predetermined interval.

In other words, the first low-temperature refrigerant branch flow path 44b is provided on one surface side of the high-temperature refrigerant branch flow path 41b, and the second low-temperature refrigerant branch flow path 45b is provided on the other surface side. The two low-temperature

refrigerant branch channels

44b and 45b are alternately arranged with respect to the high-temperature refrigerant branch channel 41b. For this reason, the flow of the high-temperature refrigerant and the low-temperature refrigerant becomes an opposite flow, and the heat transfer effect is improved. In addition, since the flow path for the high-temperature refrigerant is provided inside the housing 40 and the low-temperature refrigerant flow path is formed on the outside thereof, the temperature drop of the high-temperature refrigerant can be reduced.

Further, the casing 40 constituting the first cascade heat exchanger 9 and the material of the partition member for partitioning each refrigerant flow path are made of materials having excellent thermal conductivity. The high-temperature refrigerant, the first low-temperature refrigerant, and the second low-temperature refrigerant efficiently exchange heat by the above-described flow path configuration of the first cascade heat exchanger 9 and selection of the constituent materials, thereby improving the heat exchange efficiency. be able to.

The high-temperature refrigerant inlet 40a, the high-temperature refrigerant outlet 40b, the first low-temperature refrigerant inlet 42a, the second low-temperature refrigerant inlet 43a, the first low-temperature refrigerant outlet 42b, and the second low-temperature refrigerant outlet 43b are In addition to the above configuration, each of the side surfaces of the housing 40 may be provided, and there is no limitation.

For example, the high temperature refrigerant inlet 40a, the high temperature refrigerant outlet 40b, the first low temperature refrigerant inlet 42a, the second low temperature refrigerant inlet 43a, the first low temperature refrigerant outlet 42b, and the second low temperature refrigerant outlet 43b are: All may be provided on the same side surface of the housing 40.

FIGS. 3 to 5 are composite dual refrigeration cycle apparatus diagrams, FIG. 3 is an external perspective view of the composite dual refrigeration cycle apparatus according to the present embodiment, FIG. 4 is a front view thereof, and FIG. 5 is a side view thereof. is there. As shown in FIGS. 3 to 5, the composite binary refrigeration cycle apparatus has a housing K shown in FIG. 1 having an overall drum shape in a side view. The housing K includes a lower housing Ka having a substantially trapezoidal side surface and a substantially V-shaped upper housing Kb disposed integrally or integrally on the lower housing Ka.

The upper housing Kb is composed of a plurality (here, two sets) of heat exchanger modules M and M and the same number of blower fans FA and FB. One set of heat exchanger modules M are arranged such that a pair (two) of

air heat exchangers

21a and 21b, 28a and 28b face each other, and each of these

air heat exchangers

21a and 21b, 28a and 28b. It is comprised by arrange | positioning ventilation fan FA and FB in the space part between upper end parts.

Each heat exchanger module M is provided with a top plate Mc at its upper end, and the blower fans FA and FB are attached to the top plate Mc at positions facing each other between the heat exchanger modules M. Cylindrical air outlets Md and Md are projected above the top plate Mc, and the projecting end surfaces of the air outlets Md and Md are covered with fan guards Me and Me, respectively.

The

air heat exchangers

21a and 21b, and 28a and 28b constituting the heat exchanger module M are opposed to each other so that the top plate Mc side, which is the upper end portion, is wide and the lower housing Ka side is narrow and close to each other. Are inclined with respect to each other so as to be substantially V-shaped. In addition, a partition wall portion Mg is provided between the heat exchanger modules M and M so as not to affect the heat between the heat exchanger modules M and M. The lower housing Ka is configured in the machine room Mf. The machine room Mf includes refrigeration cycle components constituting the first and second high temperature side refrigeration circuits R1a and R1b and the first and second low temperature side refrigeration circuits R2a and R2b shown in FIG. The control device C is accommodated.

The control device C has a function of controlling the entire operation of the composite binary refrigeration cycle device. For example, an ON / OFF control function for receiving ON / OFF control of the operation of the refrigeration cycle in response to an operation signal from an operation device such as an operation panel (not shown), a switching function of the operation mode (heating / defrosting operation mode) , The function of detecting frost formation of the second

air heat exchangers

21 and 28, the function of controlling the refrigerant circulation flow rate by the opening degree control of the high-temperature side and low-temperature

side expansion devices

8, 14, 24 and 31, first and second Of the high-temperature side compressors 5 and 11, the first and second low-

temperature side compressors

18 and 25, and the first and second blower fans FA and FB per unit time (hereinafter simply referred to as the number of revolutions). It has a function to control. Although not shown, the control device C includes the first and second high temperature side compressors 5 and 11, the first and second low

temperature side compressors

18 and 25, and the first and second blower fans FA, Six inverter boards (not shown) for driving each of the FBs are stored.

When the heating operation of the composite binary refrigeration cycle apparatus is started by the control device C having such a function, the four-

way valves

19 and 26 of the first and second low temperature side refrigeration circuits R2a and R2b are in the heating operation mode. The opening degree of each

expansion device

8, 14, 24, 31 is controlled to a predetermined opening degree. Further, the

compressors

5, 11, 18, 25 and the blower fans FA and FB are started and operated at a required rotational speed.

According to the above operation, the refrigerant is led to the first high temperature side refrigeration circuit R1a, the second high temperature side refrigeration circuit R1b, the first low temperature side refrigeration circuit R2a, and the second low temperature side refrigeration circuit R2b, and sequentially circulates. .

That is, in the first high temperature side refrigeration circuit R1a, the refrigerant R134a is converted into the high temperature side compressor 5—the refrigerant side flow path 6—the high temperature side receiver 7—the high temperature side expansion device 8 in the first water / refrigerant heat exchanger 2A. -The high-temperature refrigerant flow path 10 in the first cascade heat exchanger 9-the high-temperature side compressor 5- are guided and circulated in this order.

The refrigerant side flow path 6 in the first water / refrigerant heat exchanger 2A acts as a condenser, and the high temperature refrigerant flow path 10 in the first cascade heat exchanger 9 acts as an evaporator.

In the first low-temperature side refrigeration circuit R2a, the refrigerant R410A discharged from the low-temperature side compressor 18 is transferred to the first low-temperature refrigerant flow path 33-first cascade heat in the four-way valve 19-second cascade heat exchanger 15. In the exchanger 9, the first low-temperature refrigerant flow path 20, the low-temperature side receiver 23, the low-temperature side expansion device 24, the first air heat exchanger 21, the four-way valve 19, the accumulator 22, and the low-temperature side compressor 18 are led and circulated in this order. To do.

In the second high temperature side refrigeration circuit R1b, the refrigerant R134a is supplied from the high temperature side compressor 11—the refrigerant side flow path 12—the high temperature side receiver 13—the high temperature side expansion device 14—in the second water / refrigerant heat exchanger 2B. In the second cascade heat exchanger 15, the high-temperature refrigerant flow path 16 and the high-temperature side compressor 11 are led in order and circulated.

The refrigerant side flow path 12 in the second water / refrigerant heat exchanger 2B acts as a condenser, and the high temperature refrigerant flow path 16 in the second cascade heat exchanger 15 acts as an evaporator.

In the second low-temperature side refrigeration circuit R2b, the refrigerant R410A discharged from the low-temperature side compressor 25 is transferred to the second low-temperature refrigerant flow path 27-first cascade heat in the four-way valve 26-second cascade heat exchanger 15. In the exchanger 9, the second low-temperature refrigerant flow path 34, the low-temperature side receiver 30, the low-temperature side expansion device 31, the second air heat exchanger 28, the four-way valve 26, the accumulator 29, and the low-temperature side compressor 25 are led and circulated in this order. To do.

In the first cascade heat exchanger 9, the first low-temperature refrigerant flow path 20 and the second low-temperature refrigerant flow path 34 act as a condenser, and as described above, the high-temperature refrigerant of the first high-temperature side refrigeration circuit R1a. The flow path 10 acts as an evaporator. That is, the refrigerant condenses in the first and second low-temperature

refrigerant flow paths

20 and 34 to release condensation heat, and the condensation heat evaporates while absorbing heat in the high-temperature refrigerant flow path 10.

The water or hot water led to the hot water pipe H through the pump 1 is condensed in the first high temperature side refrigeration circuit R1a in the water side flow path 3a of the first water / refrigerant heat exchanger 2A. High-temperature condensation heat is absorbed from the refrigerant-side flow path 6 of the water / refrigerant heat exchanger 2A, and rises to a high temperature. The hot water having a high temperature in the water side channel 3a of the first water / refrigerant heat exchanger 2A is guided to the water side channel 3b of the second water / refrigerant heat exchanger 2B.

In the second cascade heat exchanger 15, the first low-temperature refrigerant flow path 33 and the second low-temperature refrigerant flow path 27 act as a condenser, and as described above, the high-temperature refrigerant of the second high-temperature side refrigeration circuit R1b. The channel 16 acts as an evaporator. That is, the refrigerant condenses in the first and second low-temperature

refrigerant flow paths

33 and 27 to release condensation heat, and the condensation heat evaporates while absorbing heat in the high-temperature refrigerant flow path 16.

The hot water guided from the first water / refrigerant heat exchanger 2A to the water-side flow path 3b of the second water / refrigerant heat exchanger 2B is condensed into the first water by the second high-temperature side refrigeration circuit R1b. The high-temperature condensation heat is further absorbed from the refrigerant-side flow path 12 of the refrigerant heat exchanger 2B, and rises to a higher temperature. That is, the temperature rises to the set temperature in the water-side flow path 3b of the second water / refrigerant heat exchanger 2B.

The hot water that has risen to the set temperature from the second water / refrigerant heat exchanger 2B is led to the hot water outlet such as a hot water storage tank or hot water tap. Then, it is led again to the first and second water /

refrigerant heat exchangers

2A and 2B and heated and circulated to the hot water storage tank or discharged directly to the hot water tap.

During such heating operation, when the outside air temperature is extremely low, the first and second air heat exchangers 21, which are the evaporators of the first low-temperature side refrigeration circuit R2a and the second low-temperature side refrigeration circuit R2b, Frost adheres to 28 and the heat exchange efficiency decreases. Therefore, the controller C needs to switch the four-way valve 19 of the first low-temperature side refrigeration circuit R2b to the defrosting operation side and perform the defrosting operation of the first and second

air heat exchangers

21 and 28. is there.

However, the defrosting operation of the first and second

air heat exchangers

21 and 28 is not performed simultaneously. For example, first, the defrosting operation of the first air heat exchanger 21 in the first low-temperature side refrigeration circuit R2a is performed. After the defrosting operation is completed, the defrosting operation of the second air heat exchanger 28 in the second low temperature side refrigeration circuit R2b is performed.

Conversely, the defrosting operation of the second air heat exchanger 28 may be performed first, and the defrosting operation of the first air heat exchanger 21 may be performed after the defrosting is completed.

Next, the case where the defrosting operation of the first air heat exchanger 21 in the first low temperature side refrigeration circuit R2a is first performed will be described. In this case, the control device C switches the four-way valve 19 of the first low temperature side refrigeration circuit R2a to the reverse cycle. However, the four-way valve 26 of the second low temperature side refrigeration circuit R2b is held in the heating operation.

Next, the operation of the compressor 5 of the first high temperature side refrigeration circuit R1a and the compressor 11 of the second high temperature side refrigeration circuit R1b is stopped by the control device C or is operated at a slow speed. The operating frequency of the compressor 25 of the second low temperature side refrigeration circuit R2b during the heating operation is based on the operating frequency of the

compressors

18 and 25 when both the first and second low temperature side refrigeration circuits R2a and R2b are heated. In order to increase the compression capacity, that is, increase the heating capacity, the frequency is increased to a higher operating frequency. Furthermore, the rotation speed of the second blower fan FB is increased to the maximum rotation speed, the evaporation temperature is increased, and the capacity of the refrigeration cycle of the second low-temperature side refrigeration circuit R2b is increased.

In this state, since the hot water is not heated, the pump 1 is stopped. However, the operation of the pump 1 may be continued when it is necessary to continuously circulate the hot water due to a request from the user side.

In the first low-temperature side refrigeration circuit R2a, the high-temperature and high-pressure refrigerant discharged from the low-temperature side compressor 18 is directly led to the first air heat exchanger 21 through the four-way valve 19 and condensed. The heat of condensation is released to melt the attached frost.

At this time, the refrigerant evaporates in the first low-temperature refrigerant flow path 20 in the first cascade heat exchanger 9 and the first low-temperature refrigerant flow path 33 in the second cascade heat exchanger 15, but the second low-temperature refrigerant flow path Since the side refrigeration circuit R2b continues the heating operation, the amount of heat corresponding to the heat of evaporation is transferred to the second low-temperature refrigerant flow path 34 in the first cascade heat exchanger 9 and the second cascade heat exchanger. 15 continues to supply heat to the second low-temperature refrigerant flow path 27 in the form of condensation heat.

In this state, when the operations of the compressor 5 of the first high temperature side refrigeration circuit R1a and the compressor 11 of the second high temperature side refrigeration circuit R1b are stopped during defrosting, the first cascade heat exchange is performed. Although the first low-temperature refrigerant flow path 20 and the second low-temperature refrigerant flow path 34 in the vessel 9 are not adjacent to each other, the protrusions formed on the plate of the heat exchanger are in metal contact with each other. Heat can be exchanged by heat conduction of the plate metal.

The first low-temperature refrigerant flow path 33 and the second low-temperature refrigerant flow path 27 in the second cascade heat exchanger 15 can similarly conduct heat.

Further, when the compressor 5 of the first high temperature side refrigeration circuit R1a and the compressor 11 of the second high temperature side refrigeration circuit R1b are operated at a low speed by heating operation during defrosting, the first The first low-temperature refrigerant flow path 10 between the first low-temperature refrigerant flow path 20 and the second low-temperature refrigerant flow path 34 in the cascade heat exchanger 9 and the first low-temperature refrigerant in the second cascade heat exchanger 15. Since a flow is generated in each of the second high-temperature refrigerant flow path 16 between the refrigerant flow path 33 and the second low-temperature refrigerant flow path 27, the heat accompanying the phase change of the refrigerant in the high-temperature

refrigerant flow paths

10 and 16 is generated. You can also give and receive.

Therefore, in the first cascade heat exchanger 9 and the second cascade heat exchanger 15, the first low-temperature

refrigerant flow paths

20 and 33 in the first low-temperature side refrigeration circuit R2a being defrosted are in the heating operation. The second low-temperature refrigerant circuit R2b in the second low-temperature side refrigeration circuit R2b absorbs heat from each of the second low-temperature

refrigerant flow paths

34 and 27 to constitute a binary cycle during defrosting. Moreover, since the capacity of the compressor 25 of the second low-temperature refrigerant circuit R2b during the heating operation is increased and the second blower fan FB is operating at the maximum rotation speed, each second low-temperature refrigerant flow path 34, The amount of heat absorbed at 27 can be increased.

Thus, since the heat supply source is secured, the defrosting can be completed in a short time. Moreover, since warm water is not used as a heat source, an extreme temperature drop in the warm water in the warm water pipe H during defrosting can be prevented.

Moreover, since the operation of the pump 1 can be stopped, the outflow of unheated warm water can be prevented. However, the operation of the pump 1 may be continued when it is necessary to continuously circulate the hot water due to a request from the user side. When the defrosting of the first air heat exchanger 21 is completed, the process moves to the defrosting of the second air heat exchanger 28. That is, the four-way valve 19 of the first low-temperature side refrigeration circuit R2a is switched to the normal heating operation, and the four-way valve 26 of the second low-temperature side refrigeration circuit R2b is switched to the reverse cycle.

Next, the

compressors

5, 11, 18, 25 of each refrigeration circuit R1a, R1b, R2b, R2a are driven in the same mode as described above.

Based on the above drive, in the second low temperature side refrigeration circuit R2b, the high temperature and high pressure refrigerant discharged from the low temperature side compressor 25 is directly led to the second air heat exchanger 28 via the four-way valve 26. It condenses and releases condensation heat to melt the attached frost.

The refrigerant evaporates in the second low-temperature refrigerant flow path 34 in the first cascade heat exchanger 9 and the second low-temperature refrigerant flow path 27 in the second cascade heat exchanger 15, but the first low-temperature side refrigeration circuit Since R2a is in a heating operation, the amount of heat corresponding to the heat of evaporation is converted into the first low-temperature refrigerant flow path 20 in the first cascade heat exchanger 9 and the first amount in the second cascade heat exchanger 15. It continues to be supplied as condensation heat to the low-temperature refrigerant flow path 33.

In addition, when the compressor 5 of the first high-temperature side refrigeration circuit R1a and the compressor 11 of the second high-temperature side refrigeration circuit R1b are stopped during defrosting, and when the operation is performed at a slow speed by the heating operation. The form of heat transmission / reception is the same as that described above, and is therefore omitted.

Therefore, in the first cascade heat exchanger 9 and the second cascade heat exchanger 15, the second low-temperature

refrigerant flow paths

34 and 27 in the second low-temperature side refrigeration circuit R2b being defrosted are in the heating operation. Heat is absorbed from the first low-temperature

refrigerant flow paths

20 and 33 in the first low-temperature side refrigeration circuit R2a to constitute a two-way cycle during defrosting.

Since the heat supply source is secured in this way, defrosting can be completed in a short time. Moreover, since warm water is not used as a heat source, an extreme temperature drop in the warm water in the warm water pipe H during defrosting can be prevented. Since the pump 1 can be stopped, the outflow of warm water that is not heated can be prevented. However, the operation of the pump 1 may be continued when it is necessary to continuously circulate the hot water due to a request from the user side.

When the defrosting operation of the second air heat exchanger 28 is completed, the four-way valve 26 of the second low temperature side refrigeration circuit R2b is switched to the normal heating operation, and the compressor 5 of the first high temperature side refrigeration circuit R1a is switched. If the compressor 11 of the second high temperature side refrigeration circuit R1b and the pump 1 are stopped, the pump 1 may be driven. Therefore, in the first and second high temperature side refrigeration circuits R1a and R1b, the four-way valve and the accumulator are not required, and the configuration can be simplified.

Moreover, since a heat supply source can be secured during defrosting, defrosting can be completed in a short time. Moreover, since the temperature of the compressor is not lowered more than necessary, the capacity rises quickly when the heating operation is resumed after defrosting. Furthermore, since hot water is not used as a heat source, the pump can be stopped at the time of defrosting, and it is possible to prevent warm water below the set temperature from flowing out.

Furthermore, during the defrosting operation of one of the first and second low temperature side refrigeration circuits R2a and R2b, the

compressors

18 and 25 of the other first and second low temperature side refrigeration circuits R2a and R2b that are heated are operated. Since the operating frequency is higher than the operating frequency when both the first and second low temperature side refrigeration circuits R2a and R2b are operated for heating, the first and second blower fans FA and FB are operating at the maximum rotational speed. The defrosting time can be shortened.

In addition, since the first and second air heat exchangers 21 and 28 (heat exchanger modules M and M) are separated from each other by the partition wall portion Mg, the first and second low-temperature side refrigeration circuits R2a and R2b During one defrosting operation, the other

air heat exchangers

21 and 28 are not affected by heat and the defrosting time can be shortened.

In addition, as for this partition part Mg, the inside is previously formed as an empty space.

As shown in FIGS. 6 to 8, this empty space is a space that can appropriately accommodate a desired optional device such as a harmonic reduction device 60 described later, for example.

In addition, in FIG. 6 thru | or FIG. 8, the partition part Mg has the same structure by the front side and a back side, and demonstrates below by illustrating the front side.

When accommodating the harmonic reduction device 60 in the partition wall portion Mg, the partition wall portion Mg is closed by an outer lid 50 in which a plurality of sheet metal air holes 50a are formed as shown in FIG.

In the partition wall portion Mg, left and right partition plates 51 are provided to partition the partition wall portion Mg left and right at the left and right center in FIG. 7, and two harmonics are reduced in each of the chambers partitioned left and right as shown in FIG. The device 60 is arranged side by side in the vertical direction. That is, a total of four harmonic reduction devices 60a to 60d are accommodated in the partition wall portion Mg.

The harmonic reduction devices 60a to 60d are, for example, 18-pulse rectifiers or 12-pulse rectifiers, and can be connected to the inverter boards for the compressors housed in the control device C to reduce harmonics.

The harmonic reduction devices 60a to 60d are each provided with exhaust heat fans 61a to 61d for discharging the heat inside, and a plurality of ventilation holes (not shown) are formed on the side surfaces.

The inner lids 52a to 52d are provided inside the partition wall portion Mg so as to hide the harmonic reduction devices 54a to 54d. A gap is provided between the inner lids 52a to 52d and the outer lid 50, and the air discharged from the harmonic reduction devices 60a to 60d is discharged from the vent hole 50a of the outer lid 50 to the outside of the partition wall portion Mg. Ventilation paths 53a to 53d are formed. The inner lids 52a to 53d are provided with fan holes 54a to 54d facing the exhaust heat fans 61a to 61d in a state where the harmonic reduction devices 60a to 60d are accommodated in the partition wall portion Mg. The air discharged from the heat exhaust fans 61a to 61d is discharged to the ventilation paths 53a to 53d through the fan holes 54a to 54d.

Adjacent ventilation paths

53 a and 53 b (back

side

53 c and 53 d) are partitioned by a left and right partition plate 51. That is, four independent ventilation paths 53a to 53d are formed.

In FIG. 8, the harmonic reduction device 60a arranged at the upper left stage is connected to the inverter board for the low temperature compressor 18 of the low temperature side refrigeration circuit R2a, and the harmonic reduction device 60b arranged at the lower right stage is the high temperature side refrigeration. It is connected to the inverter board for the high temperature side compressor 5 of the circuit R1a. The harmonic reduction device 60c disposed in the upper right stage is connected to the inverter board for the low temperature side compressor 25 of the low temperature side refrigeration circuit R2b, and the harmonic reduction device 60d disposed in the lower left stage is the high temperature side refrigeration circuit R1b. It is connected to the inverter board for the high temperature side compressor 11.

In this way, the respective harmonic reduction devices 60a to 60d are arranged corresponding to the four independent ventilation paths 53a to 53d, so that they are not affected by the exhaust heat of the other harmonic reduction devices. .

It should be noted that the harmonic reduction device 60 is incorporated as necessary, and may be incorporated in up to four units or may not be incorporated in one unit.

That is, the harmonic reduction device 60 can be selectively disposed on the inverter board as necessary.

Although one embodiment of the present invention has been described above, the above-described embodiment is presented as an example and is not intended to limit the scope of the present invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

2A, 2B ... water / refrigerant heat exchanger, 3 ... water flow path, 5, 11 ... high temperature side compressor, 6a ... first refrigerant side flow path, 9 ... first cascade heat exchanger, 10, 16 ... high temperature Refrigerant flow path, 12a ... second refrigerant side flow path, 15 ... second cascade heat exchanger, 20, 33 ... first low temperature refrigerant flow path, 21 ... first air heat exchanger, 28 ... second Air heat exchanger, 34, 27 ... second low temperature refrigerant flow path, H ... hot water piping, K ... casing, R1a ... first high temperature side refrigeration circuit, R1b ... second high temperature side refrigeration circuit, R2a ... 1st low temperature side freezing circuit, R2b ... 2nd low temperature side freezing circuit, FA ... 1st ventilation fan, FB ... 2nd ventilation fan.

Claims

Two low-temperature refrigeration circuits each having a water / refrigerant heat exchanger for exchanging heat with water discharged from the high-temperature side compressor, and two low temperatures each having an evaporator composed of an air heat exchanger having a blower fan And the high-temperature side refrigeration circuit are configured to be capable of exchanging heat with each of the two low-temperature side refrigeration circuits by a cascade heat exchanger. A combined dual refrigeration cycle apparatus comprising a hot water pipe for circulating water or hot water in the water side flow path of the refrigerant heat exchanger, and a control device for controlling the entire operation of the apparatus provided in the housing; ,
The two low-temperature refrigeration circuits are connected to the control device, and when one low-temperature refrigeration circuit performs defrosting operation of the evaporator, the other low-temperature refrigeration circuit radiates heat with the cascade heat exchanger. And the rotational speed of the blower fan of the other low-temperature side refrigeration circuit is controlled to be higher than the rotational speed of the blower fan when both low-temperature side refrigeration circuits are heated together. A combined two-stage refrigeration cycle apparatus characterized by the above.
Each of the cascade heat exchangers includes a high-temperature refrigerant flow path that communicates with the high-temperature side refrigeration circuit, a first low-temperature refrigerant flow path that communicates with one low-temperature side refrigeration circuit, and a second that communicates with the other low-temperature side refrigeration circuit. The first low-temperature refrigerant flow path, the first low-temperature refrigerant flow paths and the second low-temperature refrigerant flow paths are connected in series, and the first low-temperature refrigerant flow is provided on one side of the high-temperature refrigerant flow path. The composite two-stage refrigeration cycle apparatus according to claim 1, wherein the composite two-stage refrigeration cycle apparatus comprises a plate heat exchanger in which a path is disposed and a second low-temperature refrigerant flow path is disposed on the other surface side.