Water circulation system associated with refrigerant cycle

The present invention proposes a water circulation system associated with a refrigerant cycle that can selectively heat-exchange water for cooling and heating and hot water supplying with at least one of a first refrigerant and a second refrigerant. Therefore, the present invention can improve the operation efficiency of the water circulation system associated with the refrigerant cycle.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an indoor unit of a water circulation system performing a hot water supplying function and cooling and heating functions in association with a refrigerant cycle.

2. Description of the Related Art

In the related art, indoor cooling and heating are performed by an air conditioner using the refrigerant cycle and supplying hot water is performed by a boiler with an additional heating source.

More specifically, the air conditioner includes an outdoor unit installed in an outdoor area and an indoor unit installed in an indoor area. The outdoor unit includes a compressor compressing refrigerant, an outdoor heat exchanger for exchanging heat of outdoor air with the refrigerant, and a decompressing device and the indoor unit includes an indoor heat exchanger for exchanging heat of indoor air with the refrigerant. At this time, any one of the outdoor heat exchanger and the indoor heat exchanger serves as a condenser and the other one serves as an evaporator and the compressor, the outdoor heat exchanger, the decompressing device, and the indoor heat exchanger perform a refrigerant cycle.

In addition, the boiler generates heat by using oil, gas, or electricity and heats water to supply hot water or perform floor heating.

SUMMARY OF THE INVENTION

The present invention provides a water circulation system associated with a refrigerant cycle that can selectively heat exchange water for cooling and heating and hot water supplying with at least one of a first refrigerant and a second refrigerant. The water circulation system associated with the a refrigerant cycle according to the present invention includes: a first refrigerant circulation unit where a first refrigerant exchanging heat with outdoor air flows to perform the refrigerant cycle; a second refrigerant circulation unit where a second refrigerant exchanging heat with the first refrigerant flows to perform the refrigerant cycle; a water circulation unit where water for at least one of indoor heating/cooling and hot water supplying flows; a first water heat exchanger where the heat exchange between the first refrigerant and water is performed; a second water heat exchanger where the heat exchange between the second refrigerant and water is performed; a first flow control unit that selectively prevents the flow of water to the first water refrigerant heat exchanger; and a second flow control unit that selectively prevents the flow of water to the second water refrigerant heat exchanger. Therefore, the present invention can improve the operation efficiency of the water circulation system associated with the refrigerant cycle.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1is a configuration diagram of a first embodiment of a water circulation system associated with a refrigerant cycle according to the present invention.

Referring toFIG. 1, the water circulation system S associated with the refrigerant cycle includes a first refrigerant circulation unit where first refrigerant exchanging heat with outdoor air flows to perform the refrigerant cycle, a second refrigerant circulation unit where second refrigerant exchanging heat with the first refrigerant flows to perform the refrigerant cycle, and a water circulation unit where water for at least one of indoor heating/cooling and hot water supplying. At this time, the refrigerant cycle means transmitting the heat by repetitively performing compression, condensation, expansion, and evaporation processes.

In addition, the water circulation system S associated with the refrigerant cycle includes an outdoor unit1where an outdoor heat exchanger13exchanging the first refrigerant and the outdoor air with each other is installed and an intermediator2that intermediates the outdoor1with the water circulation unit and includes a water refrigerant heat exchanger23exchanging heat between the second refrigerant and water.

Specifically, the first refrigerant circulation unit includes the outdoor heat exchanger13, a first compressor11compressing the first refrigerant, a first expansion unit14expanding the first refrigerant, a first flow switch12switching a flow direction of the first refrigerant, an intermediate heat exchanger25exchanging heat between the first refrigerant and the second refrigerant, and a first refrigerant pipe15. That is, the first refrigerant performs the refrigerant cycle while sequentially circulating any one of the first compressor11, the outdoor heat exchanger13, and the intermediate heat exchanger25and the other one of the first expansion unit14, the outdoor heat exchanger13, and the intermediate heat exchanger. Further, by the first flow switch12, the flow direction of the first refrigerant may be switched into a direction in which the first refrigerant is introduced into the outdoor heat exchanger13from the intermediate heat exchanger25through the first expansion unit14or a reverse direction.

In addition, the second refrigerant circulation unit includes the intermediate heat exchanger25, a second compressor21compressing the second refrigerant, a second expansion unit24expanding the second refrigerant, a second flow switch22switching a flow direction of the second refrigerant, the water refrigerant heat exchanger23, and a second refrigerant pipe26. That is, the second refrigerant performs the refrigerant cycle while sequentially circulating any one of the second compressor21, the intermediate heat exchanger25, and the water refrigerant heat exchanger23and the other one of the second expansion unit24, the intermediate heat exchanger25, and the water refrigerant heat exchanger23. Further, by the second flow switch22, the flow direction of the second refrigerant may be switched into a direction in which the second refrigerant is introduced into the intermediate heat exchanger25from the water refrigerant heat exchanger23through the second expansion unit24or a reverse direction.

At this time, the intermediate heat exchanger25through which the first referent, second refrigerant, and water pass at the same time is included in the first refrigerant circulation unit or included in the second refrigerant circulation unit. In addition, in the intermediate heat exchanger25, three flow passages251,252, and253for allowing the first refrigerant, second refrigerant, and water to flow, respectively are formed. Accordingly, in the intermediate heat exchanger25, the first refrigerant, second refrigerant, and water exchange heat with each other at the same time. That is, the intermediate heat exchanger25serves as the water refrigerant heat exchanger where the heat is exchanged between the water and the water in a functional sense.

In another aspect, the intermediate heat exchanger25may serve as a first water refrigerant heat exchanger where the heat is exchanged between the first refrigerant and the water and the water refrigerant heat exchanger23may serve as a second water refrigerant heat exchanger where the heat is exchanged between the second refrigerant and the water.

Meanwhile, the outdoor heat exchanger13, the first compressor11, the first expansion unit14, and the first flow switch12are installed in the outdoor unit1. In the case where the outdoor unit1is operated in a cooling mode, the outdoor heat exchanger13serves as the condenser and serves as the evaporator in the case where the outdoor unit1is operated in a heating mode.

In addition, the intermediate heat exchanger25, the water refrigerant heat exchanger23, the second compressor21, and the second flow switch22are installed in the intermediator2. Moreover, in the intermediator2, the water refrigerant heat exchanger23, a flow switch32that is mounted on a water pipe61extending to the outlet of the water refrigerant heat exchanger23and senses the flow of the water, an expansion tank33branched from any point separated from the flow switch32in the flow direction of the water, a water collection tank34into which the end of the water pipe61extending from the outlet of the water refrigerant heat exchanger23is inserted and which an auxiliary heat35is provided, and a water pump36provided at any point of the water pipe61of the outlet side of the water collection tank34.

More specifically, the water refrigerant heat exchanger23may adopt, for example, a plate-type heat exchanger as a device where the heat is exchanged between refrigerant that flows on a closed circuit of the refrigerant cycle and water that flows on the water pipe61. At least two flow passages231and232where the refrigerant and the water independently flow and exchange the heat are formed in the water refrigerant heat exchanger23.

Further, when the volume of water heated while passing through the water refrigerant heat exchanger23is expanded at an appropriate level or more, the expansion tank33performs an absorption function to absorb the expansion.

Further, the water collection tank34is a container where the water passing through the water refrigerant heat exchanger23is collected. In addition, the auxiliary heat35is mounted in the water collection tank34, such that the auxiliary heat35is selected operated in the case where a heat quantity transferred through the water refrigerant heat exchanger23does not reach a required heat quality like a case where a defrosting operation is performed.

In addition, an air vent343is formed on the top of the water collection tank34to discharge air of an overheat state that exists in the water collection tank34. Moreover, a pressure gauge341and a relief valve342are provide at one portion of the water collection tank34, such that the internal pressure of the water collection tank34may appropriately be controlled. For example, when the internal water pressure of the water collection tank34displayed through the pressure gauge341is excessively high, the relief valve342is opened to appropriately control the internal pressure of the tank.

Further, the water pump36pumps water discharged through the water pip61extending from the outlet of the water collection tank34to supply it to a hot water supplying unit4and a cooling/heating unit5.

Meanwhile, the water circulation unit includes the hot water supplying unit4where water for supplying hot water, that is, hot water supplying flows and the cooling/heating unit5where water for indoor cooling and heating flows.

More specifically, the hot water supplying unit4is a part heating and supplying water required for an operation such as user's washing or dish-washing. Specifically, a three-way valve71controlling the flow of the water is provided at any point separated from the water pump36in the flow direction of the water. The three-way valve71is a direction change valve that allows the water pumped by the water pump36to flow to the hot water supplying unit4or the cooling/heating unit5. Accordingly, each of a hot water supplying pipe62extending to the hot water supplying unit4and the cooling/heating pipe63extending to the cooling/heating unit5are connected to the outlet of the three-way valve71. In addition, the water pumped by the water pump36selectively flows to any one of the hot water supplying pipe62or the cooling/heating pipe63by the control of the three-way valve71.

A hot water supplying tank41that stores water supplied from the outside and heats the stored water and an auxiliary heat42that is provided in the hot water supplying tank41are included in the hot water supplying unit4. In addition, a water introduction portion411for introducing cooling water and a water discharge portion412for discharging heated water are provided on one side of the hot water supplying unit.

Specifically, a part of the hot water supplying pipe62extending from the three-way valve71is inputted into the hot water supplying tank41and heats the water stored in the hot water supplying tank41. That is, heat is transmitted from high-temperature water that flows along the inside of the hot water supplying pipe62to the water stored in the hot water supplying tank41. In addition, in a predetermined case, the auxiliary heat35and the auxiliary heat source operate to further supply additional heat. For example, like a case where the user needs a lot of water to take a bath, they may operate when the water needs to be heated within a short time. According to the embodiment, a water discharge device such as a shower or a home appliance device such as a humidifier may be connected to the water discharge unit412.

Meanwhile, the cooling/heating unit5includes a floor cooling/heating unit51formed by burying a part of the cooling/heating pipe63in an indoor floor and an air cooling/heating unit52that is branched from any one point of the cooling/heating pipe63and in parallel, connected with the floor cooling/heating unit51.

Specifically, the floor cooling/heating unit51may be buried in the indoor floor in the form of a meander line as shown in the figure. Further, the air cooling/heating unit52may be a fan coil unit or a radiator, etc. Further, in the air cooling/heating unit52, a part of the air cooling/heating pipe54branched from the cooling/heating pipe63is provided as a heat exchange means. Moreover, a flow passage switching valve56such as the three-way valve71is installed at a point where the air cooling/heating pipe is branched and refrigerant that flows on the cooling/heating pipe63flows by being divided into the floor cooling/heating unit51and the air cooling/heating unit52or flows to only any one of the floor cooling/heating unit51and the air cooling/heating unit52.

Further, an end portion of the hot water supplying pipe62extending from the three-way valve71is united at a point separated from an outlet of the air cooling/heating pipe54in the flow direction of the water. Therefore, in a hot water supplying mode, the refrigerant that flows on the hot water supplying pipe62is combined into the cooling/heating pipe again and thereafter, is introduced into the water refrigerant heat exchanger23.

Herein, like a point where the hot water supplying62is combined with the cooling/heating pipe63, a check valve V is installed at a point requiring backflow prevention to prevent the backflow of the water. In the same context, except for a method of installing the flow passage switching valve56, the check valve will be able to be installed at each of the outlet of the air cooling/heating pipe54and the outlet of the floor cooling/heating unit51.

Meanwhile, the water pipe61guides the flow of the water for performing any one of the hot water supplying and the indoor cooling/heating. The water pipe61includes the hot water supplying pipe62guiding the water discharged from the water pump36to the hot water supplying unit4, the cooling/heating pipe63guiding the water discharged from the water pump36to the cooling/heating unit5, a main pipe302connecting the water refrigerant heat exchanger and the water pump with each other, and a branch pipe303branched from the main pipe302in order to the water passing through any one of the hot water supplying unit4and the cooling/heating unit5to the intermediate heat exchanger25. One end of the branch pipe303is connected to one corresponding point of the main pipe302between the point where the hot water supplying pipe62and the cooling/heating pipe63are combined and the water refrigerant heat exchanger23and the other end of the branch pipe303is connected to the other point of the main pipe303corresponding to a discharge side of the water refrigerant heat exchanger.

At this time, the water circulation system associated with the refrigerant cycle further includes a first flow control unit304selectively preventing the flow of the water to the intermediate heat exchanger25, a second flow control unit306selectively preventing the flow of the water to the water refrigerant heat exchanger23, and a third flow control unit305selectively preventing the flow of water discharged from the intermediate heat exchanger25. The first flow control unit304is installed at one point of the branch pipe303corresponding to an inlet of the intermediate heat exchanger, the second flow control unit306is installed at one point of the main pipe302corresponding to a downstream side of the point where the branch pipe303is branched, and the third flow control unit305is installed at the other point of the branch pipe303corresponding to a discharge side of the intermediate heat exchanger25.

The first flow control unit304and the second flow control unit306serves to control a flowing amount of the water passing through the hot water supplying unit4and the cooling/heating unit5to the intermediate heat exchanger25and the water refrigerant heat exchanger23, respectively. In addition, the first flow control unit304and the third flow control unit305shields the introduction portion and the discharge portion of the intermediate heat exchanger25, thereby isolating water adjacent to the intermediate heat exchanger25.

Hereinafter, the flow of refrigerant in a first embodiment of a water circulation system associated with a refrigerant cycle according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2is a diagram showing the flow of refrigerant when a first embodiment of a water circulation system associated with a refrigerant cycle according to the present invention is operated in one-stage compression type,FIG. 3is a diagram showing the flow of refrigerant when a first embodiment of a water circulation system associated with a refrigerant cycle according to the present invention is operated in two-stage compression type, andFIG. 4is a diagram showing the flow of refrigerant when a first embodiment of a water circulation system associated with a refrigerant cycle according to the present invention is operated in one-stage and two-stage mixed compression type.

Referring toFIGS. 2 to 4, first, the flow of the refrigerant when the water circulation system S associated with the refrigerant cycle operates in a heating mode will be described. The water circulation system S associated with the refrigerant cycle can perform a heating operation in three operation states such as the one-stage compression operation, the two-stage compression operation, and the mixed operation.

Herein, the one-stage compression operation means an operation state in which the water that flows in any one of the hot water supplying unit4and the cooling/heating unit5is heated by the first refrigerant. The two-stage compression operation means an operation state in which the water that flows in any one of the hot water supplying unit4and the cooling/heating unit5is heated by the second refrigerant. In addition, the mixed operation means an operation state in which the water that flows in any one of the hot water supplying unit4and the cooling/heating unit is heated by the first refrigerant and the second refrigerant at the same time.

That is, in the one-stage compression operation, the water is heated by a single refrigerant cycle performed by the first refrigerant. In addition, in the two-stage compression operation, the second refrigerant is heated by a first refrigerant cycle performed by the first refrigerant and the water is heated by a second refrigerant cycle performed by the second refrigerant. Further, in the mixed operation, the water is heated by two refrigerant cycles performed by the first refrigerant and the second refrigerant at the same time.

More specifically, referring toFIG. 2, first, the flow of the refrigerant when the water circulation system S associated with the refrigerant cycle operates in the one-stage compression type will be described.

In the first refrigerant circulation unit, while the first refrigerant discharged from the first compressor11sequentially passes through the intermediate heat exchanger25, the first expansion unit14, and the outdoor heat exchanger13, the refrigerant cycle is performed. At this time, the first flow switch12maintains a state to guide the refrigerant discharged from the first compressor11to the intermediate heat exchanger25.

In addition, in the second refrigerant circulation unit, the flow of the refrigerant is stopped. That is, the operation stop of the second compressor21is maintained. Further, in the water circulation unit, the water discharged from the water pump36is introduced into any one of the hot water supplying unit4and the cooling/heating unit5. The water passing through any one of the hot water supplying unit and the cooling/heating unit5is introduced into the branch pipe303. At this time, the second flow control unit305maintains a closed state to prevent the flow of the water to the water refrigerant heat exchanger23. Further, the first flow control unit304and the second flow control unit305maintain an opened state.

In addition, the water introduced into the branch pipe303passes through the intermediate heat exchanger25. While the water passes through the intermediate heat exchanger25, the water is heated by exchange the heat with the first refrigerant. The water passing through the intermediate heat exchanger25is again introduced into the water pump36through the water collection tank34.

Next, referring toFIG. 3, first, the flow of the refrigerant when the water circulation system S associated with the refrigerant cycle operates in the two-stage compression type will be described.

In the first refrigerant circulation unit, the flow of the first refrigerant is the same as the case where the water circulation system S associated with the refrigerant cycle operates in the one-stage compression type.

In addition, in the second refrigerant circulation unit, the second refrigerant discharged from the second compressor21is introduced into the water refrigerant heat exchanger23. While the second refrigerant introduced into the water refrigerant heat exchanger23passes through the water refrigerant heat exchanger23, the second refrigerant emits the heat to the water. In addition, the second refrigerant passing through the water refrigerant heat exchanger23is expanded while passing through the second expansion unit24and thereafter is introduced into the intermediate heat exchanger25. While the second refrigerant passes through the intermediate heat exchanger25, the second refrigerant absorbs the heat from the first refrigerant and thereafter, is again introduced into the second compressor21. At this time, the second flow switch guides the second refrigerant discharged from the second compressor21to the water refrigerant heat exchanger23and guides the refrigerant passing through the intermediate heat exchanger25to the second compressor21.

Further, in the water circulation unit, the water discharged from the water pump36is introduced into any one of the hot water supplying unit4and the cooling/heating unit5. The water passing through any one of the hot water supplying unit4and the cooling/heating unit5is introduced into the main pipe302. At this time, the first flow control unit304maintains the closed state to prevent the flow of the water to the intermediate heat exchanger25. Further, the second flow control unit306maintains the opened state.

In addition, the water introduced into the main pipe302passes through the water refrigerant heat exchanger23. While the water passes through the water refrigerant heat exchanger23, the water is heated by exchange the heat with the second refrigerant. The water passing through the water refrigerant heat exchanger23is again introduced into the water pump36through the water collection tank34.

In addition, referring toFIG. 4, the flow of the refrigerant when the water circulation system S associated with the refrigerant cycle operates in the mixed compression type will be described.

In the first refrigerant circulation unit and the second refrigerant circulation unit, the flows of the first refrigerant and the second refrigerant are the same as the case where the water circulation system S associated with the refrigerant cycle operates in the two-stage compression type.

However, in the water circulation unit, the water discharged from the water pump36is introduced into any one of the hot water supplying unit4and the cooling/heating unit5. The water passing through any one of the hot water supplying unit4and the cooling/heating unit5is introduced into the main pipe302and the branch pipe303at the same time. At this time, both the first flow control unit304and the second flow control unit306maintain the opened state.

The water introduced into the main pipe302and the water introduced into the branch pipe303pass through the water refrigerant heat exchanger23and the intermediate heat exchanger25, respectively. While the water passes through the intermediate heat exchanger25, the water is heated by exchanging the heat with the first refrigerant and while the water passes through the water refrigerant heat exchanger23, the water is heated by exchanging the heat with the second refrigerant. That is, the water is heated by the first refrigerant and the second refrigerant at the same time.

In addition, the water passing through the water refrigerant heat exchanger23and the intermediate heat exchanger25is again introduced into the water pump36through the water collection tank34.

Next, in the case where the water circulation system S associated with the refrigerant cycle operates in the cooling mode, the first refrigerant and the second refrigerant flow in reverse order in the first refrigerant circulation unit and the second refrigerant circulation unit in comparison with the case where the system operates in the heating mode.

Hereinafter, the shape of an intermediate heat exchanger in a first embodiment of a water circulation system associated with a refrigerant cycle according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 5is a diagram showing the shape of an intermediate heat exchanger in a first embodiment of a water circulation system associated with a refrigerant cycle according to the present invention.

Referring toFIG. 5, the intermediate heat exchanger25is a plate-type heat exchanger25that includes three flow passages adjacent to each other where the first refrigerant, the second refrigerant, and water flow independently.

In detail, the plate-type heat exchanger25includes a plurality of plates254,255, and256that forms a plurality of flow passages251,252, and253where the first refrigerant, the second refrigerant, and water flow independently. One side of the plates254,255, and256is formed with an introduction portion257into which any one of the first refrigerant, the second refrigerant, and water is introduced and the other thereof is formed with a discharge portion258from which any one of the first refrigerant, the second refrigerant, and water is discharged. In other words, the introduction portion257and the discharger portion258communicate with the plurality of flow passages251,252, and253. However, each of the plurality of flow passages251,252, and253communicates with the introduction portion257and the discharge portion258of any one of the first refrigerant, the second refrigerant, and water so that any one of the first refrigerant, the second refrigerant, and water can flow.

At this time, the first refrigerant flows through any one flow passage252that is positioned between the remaining flow passages251and253among the plurality of flow passages251,252, and253. More specifically, the second refrigerant flows through the first flow passage251of the plurality of flow passages251,252, and254, the water flows through the third flow passage253, and the first refrigerant flows through the second flow passage252that is positioned between the first flow passage251and the third flow passage253.

Therefore, even when the water circulation system (S) associated with the refrigerant cycle is operated in any one state of the one-stage compression operation and the mixed operation, the heat exchange performance through the intermediate heat exchanger25can be maximized. In more detail, in the one-stage compression operation, the heat exchange of the first refrigerant and water is performed through the intermediate heat exchanger25, in the two-stage compression operation, the heat exchanger of the second refrigerant and water is performed through the intermediate heat exchanger25, and in the mixed operation, the heat exchange of the first refrigerant, the second refrigerant, and water is performed through the intermediate heat exchanger25. Therefore, the first refrigerant and water that flow the intermediate heat exchanger25can perform the heat exchanger in the adjacent state to each other regardless of the operation state of the water circulation system (S) associated with the refrigerant cycle.

Hereinafter, a control flow of a first embodiment of a water circulation system associated with a refrigerant cycle according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 6is a control configuration diagram of the first embodiment of the water circulation system associated with the refrigerant cycle according to the present invention,FIG. 7is a flowchart showing a control flow when the first embodiment of the water circulation system associated with the refrigerant cycle according to the present invention performs a heating operation, andFIG. 8is a flowchart showing a control flow when the first embodiment of the water circulation system associated with the refrigerant cycle according to the present invention performs a defrosting operation.

Referring toFIG. 6, the water circulation system (S) associated with the refrigerant cycle includes an outdoor temperature sensor72that senses the temperature of outdoor air, a target temperature sensor73that senses the temperature of a target to be operated by the water circulation system (S) associated with the refrigerant cycle, and a control unit75that controls the first flow controller304and the second flow controller306based on the outdoor air temperature and the target temperature. The outdoor temperature sensor72, the target temperature sensor73, the first flow control unit304, the second flow control unit306, and the control unit75are electrically connected to each other so that they can transmit and receive signals to and from each other.

The target to be operated by the water circulation system (S) associated with the refrigerant cycle means a target to be controlled for the cooling and heating and hot water supplying. For example, the target to be operated may be an indoor temperature that means the temperature of indoor air, a discharge temperature that means a temperature of water discharged from the intermediator2, an introduction temperature that means the temperature of water introduced into the intermediator2, etc.

Referring toFIG. 7, when the heating operation of the water circulation system (S) associated with the refrigerant cycle starts, the outdoor temperature that means the temperature of the outdoor air and the target temperature that means the target temperature to be operated are sensed (S11).

When the outdoor temperature is a first reference temperature or more and the target temperature is below a second reference temperature (S12), the first flow control unit304is opened and the second flow control unit306is closed (S13). However, when the outdoor temperature is a first reference temperature or more and the target temperature is below a second reference temperature (S12), the first flow control unit304is opened and the second flow control unit306is closed (S14).

The case where the first flow control unit304is opened and the second flow control unit306is closed corresponds to the one-stage compression operation and the case where the first flow control unit304is closed and the second flow control unit306is opened corresponds to the two-stage compression operation. Therefore, the case where the outdoor temperature is the first reference temperature or more and the target temperature is below the second reference temperature may be referred to as the one-stage compression condition and the case other than the case where the outdoor temperature is the first reference temperature or more and the target temperature is below the second reference temperature may be referred to as the two-stage compression condition.

At this time, the first reference temperature and the second reference temperature mean the outdoor temperature and the target temperature corresponding to the operation conditions where the efficiency of the water circulation system (S) associated with the refrigerant cycle in the case of the one-stage compression operation and the efficiency of the water circulation system (S) associated with the refrigerant cycle of the two-stage compression operation are identical.

In more detail, as the outdoor temperature is high and the target temperature is low, the efficiency of the case of the one-stage compression operation is higher than the efficiency of the case of the two-stage compression operation. On the other hand, as the outdoor temperature is low and the target temperature is high, the efficiency of the case of the two-stage compression operation is higher than the efficiency of the case of the one-stage compression operation. Therefore, while the outdoor temperature and the target temperature are changed, there may be the outdoor temperature and the target temperature where the efficiency of the case of the two-stage compression operation is the same level of the efficiency of the case of the one-stage compression operation. Therefore, according to the control flow, the operation state of the water circulation system (S) associated with the refrigerant cycle is varied in the direction where the operation efficiency is higher according to the outdoor temperature and the target temperature.

Meanwhile, if the operation stop signal of the water circulation system (S) associated with the refrigerant cycle is not input, the process is repeatedly performed.

According to the water circulation system (S) associated with the refrigerant cycle, the operation efficiency can be maximized. In more detail, when the efficiency of the one-stage compression is operated is higher the efficiency of the case of the two-stage compression operation based on the first reference temperature and the second reference temperature as a reference, the water circulation system (S) associated with the refrigerant cycle is operated in the one-stage compression type and when the efficiency of the two-stage compression operation is higher than the efficiency of the one-stage compression operation, the water circulation system (S) associated with the refrigerant cycle is operated in the two-stage compression type. Therefore, the water circulation system (S) associated with the refrigerant cycle may be operated in the direction where the operation efficiency can be maximized according to the outdoor temperature and the target temperature.

Describing the defrosting operation with reference toFIG. 8, the water circulation system associated with the refrigerant cycle is first operated in a mode set by the user's selection (S21). However, the defrosting operation to be described below is high likely to be need in the environment where the external temperature of the heat exchanger serving as an evaporator is below zero temperature, that is, the winter where the heating operation is mainly performed. Therefore, the water circulation system associated with the refrigerant cycle that performs the defrosting operation during the heating operation as described above will be described.

While the water circulation system associated with the refrigerant cycle performs the heating operation, it is determined whether the defrosting operation condition is satisfied (S22). Whether the defrosting operation condition is operated may be determined by comparing the pipe outlet temperature of the outdoor heat exchanger13with the outdoor temperature. However, in the present embodiment, the determination on whether the defrosting operation condition is satisfied may be performed in various methods and therefore, it is to be noted that the present embodiment can use a method for determining whether the defrosting operation is satisfied, without limitation.

When the defrosting operation condition is satisfied, the first refrigerant circulation unit is operated in a defrosting mode and the second refrigerant circulation unit maintains the operation mode (heating mode) (S23).

When the first refrigerant circulation unit is operated in the defrosting mode, the intermediate heat exchanger25serves as the evaporator in each refrigerant circulation units1and2and the outdoor heat exchanger25serves as a condenser. Therefore, while the first refrigerant circulation unit is operated in the defrosting mode, the defrosting of the outdoor heat exchanger13is performed by the high-temperature refrigerant that flows to the outdoor heat exchanger13.

At this time, when the intermediate heat exchanger25serves as the evaporator of each refrigerant circulation unit, the evaporation pressure of each refrigerant circulation units1and2becomes small, such that there is a risk of the performance degradation of each refrigerant circulation units1and2and the damage of each compressor.

Therefore, in the present embodiment, in order to prevent the reduction of the evaporation pressure in the intermediate heat exchanger25, while the first refrigerant circulation unit is operated in the defrosting mode, the first flow control unit304and the third flow control unit305are closed (S24). The flow of water stops in the branch pipe303and the hot water is heat exchanged with the first refrigerant inside the branch pipe303. The first refrigerant heat exchanged with the hot water and the second refrigerant is heat exchanged, such that the temperature of each refrigerant is increased, thereby making it possible to minimize the reduction of the evaporation pressure of each refrigerant circulation unit.

Next, while the first refrigerant circulation unit is operated in the defrosting mode, it is determined whether the defrosting is ended (S25).

If it is determined whether the defrosting is ended, the closed first flow control unit304and third control unit305are opened (S26). The first refrigerant circulation unit is operated in a previous mode (S27). That is, the first refrigerant circulation unit is operated in a heating mode.

According to the above-mentioned embodiment, while the first refrigerant circulation unit is operated in the defrosting mode, the second refrigerant circulation unit is continuously operated in the heating mode, such that the indoor heating or the hot water supplying can be performed. In addition, the hot water of the branch pipe303is heat exchanged with the first refrigerant that flows to the intermediate heat exchanger25to increase the temperature of the first refrigerant, such that the evaporation pressure of each refrigerant circulation unit is minimized, thereby making it possible to minimize the performance degradation of each refrigerant circulation unit.

Hereinafter, a second embodiment of a water circulation system associated with a refrigerant cycle according to the present invention will be described in detail with reference to the accompanying drawings. The second embodiment is different from the first embodiment in that the intermediate heat exchanger is formed in a triple-pipe, the mixed operation is performed during the reference time in the case of the two-stage compression condition, and the first flow control unit304and the third flow control unit305are opened during the defrosting operation.

FIG. 9is a diagram showing a shape of the intermediate heat exchanger of the second embodiment of the water circulation system associated with the refrigerant cycle according to the present invention,FIG. 10is a flowchart showing a control flow when the second embodiment of the water circulation system associated with the refrigerant cycle according to the present invention performs a heating operation, andFIG. 11is a flowchart showing a control flow when the second embodiment of the water circulation system associated with the refrigerant cycle according to the present invention performs a defrosting operation.

Referring toFIG. 9, in the second embodiment, the intermediate heat exchanger85is a triple-pipe shape in which three independent flow passages are formed by three pipes having a concentric axis and different diameters. Specifically, the intermediate heat exchanger85includes a first flow passage851positioned at the innermost side, a second flow passage852positioned outside of the first flow passage851, and a third flow passage853positioned outside of the second flow passage852. The first flow passage851is in communication with a second refrigerant pipe26through which second refrigerant flows, the second flow passage852is in communication with a first refrigerant pipe15through which first refrigerant flows, and the third flow passage853is in communication with a water pipe303through which water flows. That is, the second refrigerant flows through the first flow passage851, the first refrigerant flows through the second flow passage852, and the water flows through the third flow passage853.

On the other hand, the intermediate heat exchanger85includes a plurality of heat exchanging units86and87that are removably connected with each other. The heat exchanging units86and87each include three flow passages851,852, and853. Each of the heat exchange units86and87is connected to the first refrigerant pipe15, the second refrigerant pipe26, and the water pipe303.

At this time, a plurality of introduction portions881,883, and885and refrigerant discharge portions882,884, and886that are selectively connected to each of the plurality of heat exchanging units86and87are provided in the first refrigerant pipe15, the second refrigerant pipe26, and the water pipe303. More specifically, the plurality of introduction portions881,883, and885and refrigerant discharge portions882,884, and886include a first refrigerant introduction portion881and a first refrigerant discharge portion882for introducing and discharging the first refrigerant, a second refrigerant introduction portion883and a second refrigerant discharge portion884for introducing and discharging the second refrigerant, and a water introduction portion885and a water discharge portion886for introducing and discharging the water.

In addition, each of the plurality of introduction portion881,883, and885and discharge portions882,884, and886includes a plurality of flow preventing portions857for selectively shielding the plurality of introduction portion881,883, and885and discharge portions882,884, and886. The plurality of flow preventing portions857selectively prevents the flow of at least one of the first refrigerant, the second refrigerant, and the water through the plurality of introduction portion881,883, and885and discharge portions882,884, and886.

Meanwhile, the heat exchange capacity of the intermediate heat exchanger85may be varied depending on the number of the heat exchanging units86and87connected to the first refrigerant pipe15, the second refrigerant pipe26, and the water pipe303. Further, as the flow of the refrigerant to the plurality of heat exchanging units86and87is selectively prevented by the plurality of flow preventing portions857, the heat exchange capacity of the intermediate heat exchanger85may be varied.

More specifically, since the heat exchanging units86and87are selectively and removably connected to the introduction portions881,883, and885and the discharge portions882,884, and886, the heat exchanging unit86and87may be connected to the introduction portions881,883, and885and the discharge portions882,884, and886by changing the number of connected portions as necessary.

Further, by preventing the flow of the first refrigerant, the second refrigerant, and the water to the heat exchanging units86and87by means of the flow preventing portion857even in the state where the heat exchanging units86an87are connected to the introduction portions881,883, and885and the discharge portions882,884, and886, the number of the heat exchanging units86and87substantially used for exchanging the heat may be varied. By this method, the entire heat exchanging capacity of the intermediate heat exchanger85may be varied. By this method, the entire heat exchanging capacity of the intermediate heat exchanger85may be varied.

Meanwhile, the type in which the first refrigerant, the second refrigerant, and the water flows through three flow passages851,852, and853has various numbers of cases. That is, the first refrigerant flows through any one of three flow passages851,852, and853, the second refrigerant flows through another of three flow passages851,852, and853, and the water flows through the other one of three flow passages851,852, and853. Accordingly, the first refrigerant, the second refrigerant, and the water may flow through three flow passages851,852, and853in six types.

Further, the flow directions of fluids that flow through adjacent flow passages among the fluids that flow through three flow passages851,852, and853are opposite to each other. At this time, the fluids include the first refrigerant, the second refrigerant, and the water. That is, two fluids that flow adjacent to each other among the first refrigerant, the second refrigerant, and the water flow opposite to each other in the intermediate heat exchanger85. Accordingly, the heat exchange efficiency of the intermediate heat exchanger85can further be improved.

Referring toFIG. 10, in the present embodiment, the mixed operation is performed during the reference time in the case corresponding to the two-stage compression condition.

In detail, when the operation of the water circulation system (S) associated with the refrigerant cycle starts, the outdoor temperature and the target temperature are sensed (S31). In the case where the outdoor temperature and the target temperature correspond to the one-stage compression condition (S32), the first flow control unit304is opened and the second flow control unit306is closed, such that the one-stage compression operation starts (S33).

However, when the outdoor temperature and the target temperature does not correspond to the one-stage compression condition, that is, when they correspond to the two-stage compression condition (S32), both the first flow control unit304and the second flow control unit306are opened, such that the mixed operation starts (S34).

After the mixed operation starts and the reference time elapses (S35), the outdoor temperature and the target temperature are sensed (S36). When the outdoor temperature and the target temperature still correspond to the two-stage compression condition (S37), the first flow control unit304is closed, such that the two-stage compression operation starts (S38). However, when the outdoor temperature and the target temperature are changed in the one-stage compression condition (S37), the outdoor temperature and the target temperature are sensed again (S31). At this time, the reference time means the time required from the time when the first flow control unit304and the second flow control unit306are switched to the time when the outdoor temperature and the target temperature are stabilized.

If the operation stop signal of the water circulation system (S) associated with the refrigerant cycle is not input, the process is repeatedly performed.

According to the present embodiment, the efficiency of the water circulation system (S) associated with the refrigerant cycle can be optionally maintained according to the change in the outdoor temperature and the target temperature.

In more detail, even when the outdoor temperature and the target temperature correspond to the two-stage compression condition, the efficiency of the mixed operation may be higher than that of the two-stage compression operation. For example, when the outdoor temperature and the target temperature have a value approximating to the first reference temperature and the second reference temperature, the efficiency of the mixed operation may be higher than that of the two-stage compression.

However, in the present embodiment, when the outdoor temperature and the target temperature deviates from the one-stage compression condition, the mixed operation is primarily performed during the reference time and despite of the mixed operation, when they does not enter the one-stage compression condition, the two-stage compression operation is finally performed. Therefore, the efficiency of the water circulation system (S) associated with the refrigerant cycle can be optionally maintained according to the outdoor temperature and the target temperature.

Describing the defrosting operation with reference toFIG. 11, the water circulation system associated with the refrigerant cycle is first operated in a mode set by the user's selection (S41). However, the case where the present embodiment performs the defrosting operation during the heating operation will be described below.

The first flow control unit304and the third flow control unit305of the branch pipe303maintain the closed state while each of the refrigerant circulation units1and2performs the heating operation. Further, the second flow control unit306maintains the opened state. Therefore, the water passing through the water circulation unit is heat exchanged with the second refrigerant while passing through the water refrigerant heat exchanger23.

When the second refrigerant circulation unit is operated in the heating mode, the temperature of water flowing to the water pipe61is continuously increased. In particular, the temperature of water flowing to the main pipe302adjacent to the water refrigerant heat exchanger23is continuously increased.

It is determined whether the defrosting operation condition is satisfied while the water circulation system is operated in the set mode (S42). When the defrosting operation condition is satisfied, the first refrigerant circulation unit is operated in the defrosting mode and the second refrigerant circulation unit maintains the original operation mode (heating mode).

When the first refrigerant circulation unit is operated in the defrosting mode, the first flow control unit304and the third flow control unit305are opened (S14). When the first flow control unit304and the third flow control unit305are opened, at least a part of the hot water flowing to the water circulation unit is heat exchanged with the first refrigerant while flowing to the intermediate heat exchanger25. The first refrigerant heat exchanged with the hot water and the second refrigerant is heat exchanged, such that the temperature of each refrigerant is increased, thereby making it possible to minimize the reduction of the evaporation pressure of each refrigerant circulation unit.

Next, while the first refrigerant circulation unit is operated in the defrosting mode, it is determined whether the defrosting is ended (S45). If it is determined whether the defrosting is ended, the closed first flow control unit304and third control unit305are closed (S46). The first refrigerant circulation unit is operated in a previous mode (S47). That is, the first refrigerant circulation unit will be operated in the heating mode.

In addition to the above-mentioned two embodiments, the following embodiment will be described.

When the first refrigerant circulation unit is operated in the defrosting mode while each of the refrigerant circulation units1and2is operated in the heating mode, if the first flow control unit304and the third flow control unit305are in the closed state, the first flow control unit204and the third flow control unit305are opened and if the defrosting is ended, the first flow control unit304and the third flow control unit305can be closed. On the other hand, if the first flow control unit304and the third flow control unit305are in the opened state, the first flow control unit304and the third flow control unit305may be maintained in the opened state.

Hereinafter, a fourth embodiment of a water circulation system associated with a refrigerant cycle according to the present invention will be described in detail with reference to the accompanying drawings. The fourth embodiment is different from the first embodiment in that the flowing amount of water to the intermediate heat exchanger and the water refrigerant heat exchanger is controlled according to the outdoor temperature and the target temperature and when the defrosting operation is performed, it is opposite to the case of the heating operation in terms of the refrigerant flowing of the first refrigerant circulation unit and the second circulation unit.

FIG. 12is a flowchart showing a control flow when a third embodiment of a water circulation system associated with a refrigerant cycle according to the present invention performs a heating operation andFIG. 13is a flowchart showing a mixed operation process based on an outdoor temperature in the third embodiment of the water circulation system associated with the refrigerant cycle according to the present invention.FIG. 14is a flowchart showing a mixed operation process based on a target temperature in the third embodiment of the water circulation system associated with the refrigerant cycle according to the present invention andFIG. 15is a flowchart showing a control flow when the third embodiment of the water circulation system associated with the refrigerant cycle according to the present invention performs a defrosting operation.

Referring toFIGS. 12 to 14, in the present embodiment, when the water circulation system (S) associated with the refrigerant cycle performs the mixed operation, the flowing amount of water to the intermediate heat exchanger25and the water refrigerant heat exchanger23is controlled according to the outdoor temperature and the target temperature.

In detail, when the operation of the water circulation system (S) associated with the refrigerant cycle starts, the outdoor temperature and the target temperature are sensed (S51). In the case where the outdoor temperature and the target temperature correspond to the one-stage compression condition (S52), the first flow control unit304is opened and the second flow control unit306is closed, such that the one-stage compression operation starts (S53).

However, the case other than the case where the outdoor temperature and the target temperature corresponds to the one-stage compression condition (S52), it determines whether the outdoor temperature is below the first reference temperature and the target temperature is the second reference temperature or more (S54). However, when the outdoor temperature is below the first reference temperature and the target temperature is the second reference temperature or more (S54), the first flow control unit304is closed and the second flow control unit306is opened (S55).

Herein, the state where the first flow control unit304is closed and the second flow control unit306is opened means the two-stage compression operation. Therefore, the case where the outdoor temperature is below the first reference temperature and the target temperature is the second reference temperature or more may be referred to the two-stage compression condition.

However, the case where the outdoor temperature and the target temperature do not correspond to the two-stage compression condition (S54), it determines whether the outdoor temperature is below the first reference temperature (S56) and the target temperature is the second reference temperature or more (S58).

The case where the outdoor temperature and the target temperature do not correspond to the two-stage compression condition (S54) and the outdoor temperature is below the first reference temperature (S56) or the target temperature is the second reference temperature or more (S58) may be referred to the mixed condition.

The case where the outdoor temperature and the target temperature do correspond to the mixed condition (S56and S58), the mixed operation starts (S57and S59). The mixed operation includes the outdoor temperature reference mixed operation and the target temperature reference mixed operation.

In more detail, the case where the outdoor temperature and the target temperature do not correspond to the two-stage compression condition and the outdoor temperature is below the first reference temperature may be referred to as the outdoor temperature reference mixed condition and the case where the outdoor temperature and the target temperature do not correspond to the two-stage compression condition and the target temperature is the second reference temperature or more may be referred to as the target temperature reference mixed condition. When the outdoor temperature and the target temperature corresponds to the outdoor temperature reference mixed condition (S56), the outdoor temperature reference mixed operation is performed (S57) and when they corresponds to the target temperature reference mixed condition (S58), the target temperature reference mixed operation is performed (S59).

Referring toFIG. 11, when the outdoor temperature reference mixed operation is performed, it determines whether the outdoor temperature is below the third reference temperature (S571). When the outdoor temperature is below the third reference temperature, the two-stage compression operation is performed (S572).

However, when the outdoor temperature corresponds to the third reference temperature or more (S571), the opening degrees of the first flow control unit304and the second flow control unit306are controlled so that the ratio of the difference of the first reference temperature and the outdoor temperature with respect to the difference of the first reference temperature and the third reference temperature is the same as the ratio of the opening degree of the second flow control unit306with respect to the opening degree of the first flow control unit304(S573).

At this time, the third reference temperature means the outdoor temperature that makes the efficiency of the mixed operation and the efficiency of the two-stage compression operation same. In other words, when the outdoor temperature is higher than the third reference temperature, the efficiency of the mixed operation is higher than that of the two-stage compression operation. To the contrary, when the outdoor temperature is lower than the third reference temperature, the efficiency of the two-stage compression operation is higher than that of the mixed operation. The third reference temperature corresponds to a temperature value smaller than the first reference temperature.

Referring toFIG. 12, when the target temperature reference mixed operation is performed, it determines whether the target temperature corresponds to a fourth reference temperature or more (S591). When the outdoor temperature corresponds to the fourth reference temperature or more, the two-stage compression operation is performed (S592).

However, when the outdoor temperature is below the fourth reference temperature (S591), the opening degrees of the first flow control unit304and the second flow control unit306are controlled so that the ratio of the difference of the first reference temperature and the outdoor temperature with respect to the difference of the fourth reference temperature and the second reference temperature is the same as the ratio of the opening degree of the second flow control unit306with respect to the opening degree of the second flow control unit306(S593).

At this time, the fourth reference temperature means the target temperature that makes the efficiency of the mixed operation and the efficiency of the two-stage compression operation same. In other words, when the target temperature is higher than the fourth reference temperature, the efficiency of the two-stage compression operation is higher than that of the mixed operation. To the contrary, when the target temperature is lower than the fourth reference temperature, the efficiency of the mixed operation is higher than that of the two-stage compression operation. The fourth reference temperature corresponds to a temperature value higher than the second reference temperature.

According to the present embodiment, the operation efficiency of the water circulation system (S) associated with the refrigerant cycle can be more optimized according to the change in the outdoor temperature and the target temperature. In detail, in the case of the mixed condition, the opening degrees of the first flow control unit304and the second flow control unit306are varied according to any one of the difference of the outdoor temperature and the third reference temperature and the difference of the target temperature and the fourth reference temperature.

In detail, in the case of the outdoor temperature reference mixed condition, as the outdoor temperature approaches to the first reference temperature, the opening degree of the first flow control unit304is relatively increased compared to the opening degree of the second flow control unit306. In other words, as the outdoor temperature approaches to the first reference temperature, the water circulation system (S) associated with the refrigerant cycle is operated in a state close to the one-stage compression operation. To the contrary, when the outdoor temperature approaches to the third reference temperature, the opening degree of the second flow control unit306is relatively increased compared to the opening degree of the first flow control unit304. In other words, as the outdoor temperature approaches to the third reference temperature, the water circulation system (S) associated with the refrigerant cycle is operated in a state close to the two-stage compression operation.

In detail, in the case of the target temperature reference mixed condition, as the target temperature approaches to the second reference temperature, the opening degree of the first flow control unit304is relatively increased compared to the opening degree of the second flow control unit306. In other words, as the target temperature approaches to the second reference temperature, the water circulation system (S) associated with the refrigerant cycle is operated in a state close to the one-stage compression operation. To the contrary, when the outdoor temperature approaches to the fourth reference temperature, the opening degree of the second flow control unit306is relatively increased compared to the opening degree of the first flow control unit304. In other words, as the outdoor temperature approaches to the fourth reference temperature, the water circulation system (S) associated with the refrigerant cycle is operated in a state close to the two-stage compression operation.

In other words, in the case of satisfying the mixed operation, the flowing amount of water to the intermediate heat exchanger25and the flowing amount of water to the water refrigerant heat exchanger23are varied to be in inverse proportion to each other.

Therefore, the water circulation system (S) associated with the refrigerant cycle can be optionally operated according to the outdoor temperature and the target temperature.

Describing the defrosting operation with reference toFIG. 15, the water circulation system (S) associated with the refrigerant cycle is first operated in a mode set by the user's selection (S61). The case where the defrosting operation is performed during the heating operation will be described below.

It is determined whether the defrosting operation condition is satisfied while the water circulation system (S) is operated in the set mode (S62). If the defrosting operation condition is satisfied, both the first refrigerant circulation unit and the second refrigerant circulation unit are operated in the defrosting mode (S63).

In the present embodiment, the case where the first refrigerant circulation unit is operated in the defrosting mode means the case where the first refrigerant circulation unit is operated in the cooling mode.

The case where the second refrigerant circulation unit is operated in the defrosting mode means the following two cases. The first case means the case where the operation of the second refrigerant circulation unit stops and the second case means the case where the second compressor21is operated at a lower frequency than the operation frequency of the second compressor in the previous mode while the second refrigerant circulation unit is basically operated in the heating mode.

In the first case, when the second refrigerant circulation unit is operated in the heating mode, if the first flow control unit304and the third flow control unit305are opened, the first flow control unit304and the third flow control unit305are closed. As described in the first embodiment, when the first flow control unit304and the third flow control unit305are closed, the hot water inside the branch pipe303and the first refrigerant are heat exchanged with each other.

In the second case, when the second refrigerant circulation unit is operated in the heating mode, the first flow control unit304and the third flow control unit305may be the closed state or the opened stated and the opening or closing of the first flow control unit304and the third flow control unit305can be controlled in the method described in the previous embodiments when the first refrigerant circulation units1and2are operated in the defrosting mode.

According to the two cases, it can be easily appreciated that the reduction of the evaporation pressure of each refrigerant circulation units1and2can be minimized. Next, while each refrigerant circulation unit is operated in the defrosting mode, it is determined whether the defrosting is ended (S64). When the defrosting is ended, each refrigerant circulation unit is operated in the previous mode (S65). That is, each refrigerant circulation unit will be operated in the heating mode.

Hereinafter, a fifth embodiment of a water circulation system associated with a refrigerant cycle according to the present invention will be described in detail with reference to the accompanying drawings. The fifth embodiment is different from the first embodiment in that the first flow control unit and the second flow control unit are controlled according to the operation or not of the second compressor and the flowing amount of water flowing to the water circulation unit is reduced during the defrosting operation.

FIG. 16is a control configuration diagram of a fourth embodiment of a water circulation system associated with a refrigerant cycle according to the present invention,FIG. 17is a flowchart showing a control flow when the fourth embodiment of the water circulation system associated with the refrigerant cycle according to the present invention performs a heating operation, andFIG. 18is a flowchart showing a control flow when the fourth embodiment of the water circulation system associated with the refrigerant cycle according to the present invention performs a defrosting operation.

Referring toFIGS. 16 and 17, in the present embodiment, the first flow control unit304and the second flow control unit306are controlled according to the operation or not of the second compressor21. In other words, the present embodiment includes a second compressor operation sensing unit91that senses the operation or not of the second compressor21and transmits it to the control unit95.

In more detail, when the operation of the water circulation system (S) associated with the refrigerant cycle starts, the operation of the second operation21is sensed (S71). At this time, as a method of sensing the operation of the second compressor21, there may be a rotation sensor that senses the rotation or not of the compressor or a method for sensing the current or voltage supplied to the compressor, etc.

When the operation of the second compressor21stops (S72), the first flow control unit304is opened and the second flow control unit306is closed (S73). In other words, when it is sensed as the operation of the second compressor stops, the one-stage compression operation is performed (S73).

As the case where the operation of the second compressor21stops, there may be various situations such as the malfunction or fault of the second compressor21, etc. Since the flowing of the second refrigerant stops in the state where the second compressor21stops, the water introduced into the water refrigerant heat exchanger23passes therethrough without the change in state. In this case, the water continuously flows to the water refrigerant heat exchanger23, which may have a bad effect on the operation for the indoor cooling and heating and the hot water supplying.

In the present embodiment, when the second compressor21stops, the flowing of water to the water refrigerant heat exchanger23is prevented. Therefore, even though a sudden situation such as the case of the failure of the second compressor21occurs, the indoor cooling and heating or the hot water supplying operations can be stably continued. Describing the defrosting operation of the embodiment with reference toFIG. 18, the water circulation system (S) associated with the refrigerant cycle is first operated in a mode set by the user's selection (S81).

It is determined whether the defrosting operation condition is satisfied while the water circulation system (S) is operated in the set mode (S82). When the defrosting operation condition is satisfied, the first refrigerant circulation unit is operated in the defrosting mode and the second refrigerant circulation unit maintains the original operation mode (heating mode) (S83).

When the first refrigerant circulation unit is operated in the defrosting mode, the intermediate heat exchanger25serves as the evaporator for each refrigerant circulation units1and2.

At this time, the intermediated heat exchanger serves as the evaporator for each refrigerant circulation unit, such that the evaporation pressure of each refrigerant circulation unit becomes small, thereby makes the condensing temperature of the second heat exchanger23low. When the condensing temperature of the second heat exchanger23is low, the temperature of water stored in the water collection tank34is low.

When the temperature of water stored in the water collection tank34is low, the temperature of water flowing to the cooling and heating pipe63of the cooling and heating unit5is low, such that the indoor temperature may be low. Therefore, in the present embodiment, when the first refrigerant circulation unit is operated in the defrosting modes, the operation of the water pump36is changed so that the amount of water flowing to the water circulation unit is more reduced than when the first refrigerant circulation unit is operated in the heating mode (S84). In this case, the amount of water flowing to the cooling and heating pipe63of the cooling and heating unit5is reduced, thereby making it possible to minimize the reduction of the indoor temperature.

Next, while the first refrigerant circulation unit is operated in the defrosting mode, it is determined whether the defrosting is ended (S85). When the defrosting is ended, the water pump36is operated in the previous state, such that the flowing amount of the cooling and heating pipe63is returned to the previous state (S86). The first refrigerant circulation unit is operated in the previous mode (S87).