Patent Description:
A representative example of a heat pump device that executes a refrigeration cycle using a refrigerant is an air conditioner. In the air conditioner, when a commercial AC power source is lost due to a power failure or the like, an internal valve is closed to prevent a refrigerant leakage (see, for example, <CIT>).

On the other hand, when the air conditioner is removed, it is required to appropriately collect the refrigerant inside.

<CIT> discloses an air conditioner capable of adjusting the amount of refrigerant circulating in a refrigerant circuit. <CIT> discloses an apparatus for controlling opening and closing of a valve having a configuration for inhibiting power supply to a proportional valve, when a driving circuit of the proportional valve is failed, while suppressing increase of costs and mounting areas of electronic components.

When an existing air conditioner is removed, the air conditioner is generally physically disconnected from the commercial AC power source, and then a collection worker collects the refrigerant inside using a refrigerant collector. However, when the internal valve is closed, there is a closed section on the refrigerant circuit, and the refrigerant cannot be completely collected although sucked by the refrigerant collector.

An object of the present invention is to more reliably collect a refrigerant from a heat pump device such as an air conditioner to be removed.

The present invention is defined by the independent claim <NUM>. The dependent claims describe optional features and preferred embodiments.

In this case, the refrigerant can be collected from before and after the heat exchanger in which a relatively large amount of refrigerant is likely to remain.

Hereinafter, embodiments of a heat pump device and a valve opening circuit of the heat pump device will be described.

A representative example of the heat pump device is an air conditioner. The air conditioner will be described as an example.

<FIG> is a schematic configuration diagram of a refrigerant circuit of an air conditioner <NUM>. The air conditioner <NUM> is a device that performs cooling or heating in a building by a vapor compression refrigeration cycle. The air conditioner <NUM> is configured by connecting an outdoor unit <NUM> and an indoor unit <NUM> by a refrigerant circuit <NUM>. Although only one indoor unit <NUM> is illustrated, a plurality of indoor units <NUM> are actually connected in parallel in accordance with a scale of equipment. As a refrigerant, for example, R32 is used.

The outdoor unit <NUM> is installed outdoors or outside a room in a building. The outdoor unit <NUM> is connected to the indoor unit <NUM> via a liquid-refrigerant connection pipe <NUM>L and a gas-refrigerant connection pipe <NUM>G. The outdoor unit <NUM> includes a compressor <NUM>, a check valve <NUM>, a four-way switching valve <NUM>, an accumulator <NUM>, an outdoor heat exchanger <NUM>, an outdoor expansion valve <NUM>, a refrigerant cooler <NUM>, an expansion valve <NUM> for returning refrigerant, an expansion valve <NUM> for adjusting liquid-refrigerant pressure, a liquid-side shutoff valve <NUM>, and a gas-side shutoff valve <NUM>.

The four-way switching valve <NUM> can mutually switch between a heat radiation operation state in which the outdoor heat exchanger <NUM> functions as a refrigerant radiator, and an evaporation operation state in which the outdoor heat exchanger <NUM> functions as a refrigerant evaporator. The four-way switching valve <NUM> and a suction side of the compressor <NUM> are connected via a suction refrigerant pipe <NUM>. The suction refrigerant pipe <NUM> is provided with the accumulator <NUM> that temporarily accumulates a refrigerant suctioned into the compressor <NUM>. The compressor <NUM> is a device for compressing the refrigerant, and for example, a device having a sealed structure such as a rotary type or a scroll type is used.

The check valve <NUM> for prevention of a backflow is provided in between in a discharge refrigerant pipe <NUM> connecting a discharge side of the compressor <NUM> and the four-way switching valve <NUM>. The four-way switching valve <NUM> and a gas-side end of the outdoor heat exchanger <NUM> are connected by a first outdoor gas-refrigerant pipe <NUM>. A liquid-side end of the outdoor heat exchanger <NUM> and the liquid-refrigerant connection pipe <NUM>L are connected via an outdoor liquid-refrigerant pipe <NUM>.

At a connecting part between the outdoor liquid-refrigerant pipe <NUM> and the liquid-refrigerant connection pipe <NUM>L, the liquid-side shutoff valve <NUM> is provided. The four-way switching valve <NUM> and the gas-refrigerant connection pipe <NUM>G are connected via a second outdoor gas-refrigerant pipe <NUM>. At a connecting part between the second outdoor gas-refrigerant pipe <NUM> and the gas-refrigerant connection pipe <NUM>G, the gas-side shutoff valve <NUM> is provided. The liquid-side shutoff valve <NUM> and the gas-side shutoff valve <NUM> are valves to be manually opened and closed, for example.

When the outdoor heat exchanger <NUM> functions as a refrigerant radiator (hereinafter referred to as an "outdoor heat radiation state"), the four-way switching valve <NUM> connects the discharge side of the compressor <NUM> and a gas side of the outdoor heat exchanger <NUM> (a state of the four-way switching valve <NUM> indicated by a solid line in <FIG>). When the outdoor heat exchanger <NUM> functions as a refrigerant evaporator (hereinafter referred to as an "outdoor heat evaporation state"), the suction side of the compressor <NUM> and the gas side of the outdoor heat exchanger <NUM> (a state of the four-way switching valve <NUM> indicated by a broken line in <FIG>) are connected. At a time of the cooling operation, the four-way switching valve <NUM> is switched to the outdoor heat radiation state. At a time of the heating operation, the four-way switching valve <NUM> is switched to the outdoor heat evaporation state.

The outdoor heat exchanger <NUM> functions as a refrigerant radiator or functions as a refrigerant evaporator. The outdoor fan <NUM> supplies outdoor air as a cooling source or a heating source of the refrigerant flowing through the outdoor heat exchanger <NUM>, to the outdoor heat exchanger <NUM>.

The outdoor expansion valve <NUM> and the expansion valve <NUM> are provided on the outdoor liquid-refrigerant pipe <NUM>. The outdoor expansion valve <NUM> is an electric valve that decompresses the refrigerant during the heating operation, and is provided at a portion of the outdoor liquid-refrigerant pipe <NUM> close to the liquid-side end of the outdoor heat exchanger <NUM>. The expansion valve <NUM> is an electric valve that decompresses the refrigerant such that the refrigerant flowing through the liquid-refrigerant connection pipe <NUM>L is in a gas-liquid two-phase state during the cooling operation, and is provided in a portion of the outdoor liquid-refrigerant pipe <NUM> close to the liquid-refrigerant connection pipe <NUM>L. The expansion valve <NUM> is provided at a portion of the outdoor liquid-refrigerant pipe <NUM> closer to the liquid-refrigerant connection pipe <NUM>L than the outdoor expansion valve <NUM>.

During the cooling operation, the air conditioner <NUM> causes the refrigerant in the gas-liquid two-phase state to flow into the liquid-refrigerant connection pipe <NUM>L by the expansion valve <NUM>, and performs two-phase conveyance of the refrigerant sent from the outdoor unit <NUM> to the indoor unit <NUM>.

To the refrigerant cooler <NUM>, a refrigerant return pipe <NUM> having the expansion valve <NUM> interposed in between is connected. To the refrigerant cooler <NUM>, a refrigerant return outlet pipe <NUM> is connected. The refrigerant return outlet pipe <NUM> is connected to the suction refrigerant pipe <NUM>.

A part of the refrigerant flowing through the outdoor liquid-refrigerant pipe <NUM> is split from a portion between the outdoor expansion valve <NUM> and the refrigerant cooler <NUM>, and sent to an inlet (a left side in <FIG>) of the refrigerant cooler <NUM> close to the refrigerant return pipe <NUM>. The expansion valve <NUM> of the refrigerant return pipe <NUM> decompresses the refrigerant flowing in the refrigerant return pipe <NUM> as well as adjusting a flow rate of the refrigerant flowing in the refrigerant cooler <NUM>. The expansion valve <NUM> is an electric valve.

The refrigerant return outlet pipe <NUM> sends the refrigerant to from an outlet of the refrigerant cooler <NUM> close to the refrigerant return pipe <NUM> to the suction refrigerant pipe <NUM>. The refrigerant return outlet pipe <NUM> of the refrigerant return pipe <NUM> is connected to the accumulator <NUM> via the suction refrigerant pipe <NUM>.

The refrigerant cooler <NUM> is a heat exchanger that cools the refrigerant flowing through a portion of the outdoor liquid-refrigerant pipe <NUM> closer to the outdoor heat exchanger <NUM> than the expansion valve <NUM> by the refrigerant flowing through the refrigerant return pipe <NUM>. In the refrigerant cooler <NUM>, the refrigerant flowing through the refrigerant return pipe <NUM> and the refrigerant flowing through the outdoor liquid-refrigerant pipe <NUM> are counterflow during the cooling operation.

The indoor unit <NUM> is installed inside a room in a building. As described above, the indoor unit <NUM> is connected to the outdoor unit <NUM> via the liquid-refrigerant connection pipe <NUM>L and the gas-refrigerant connection pipe <NUM>G to constitute a part of the refrigerant circuit <NUM>.

The indoor unit <NUM> mainly has an indoor expansion valve <NUM> and an indoor heat exchanger <NUM>. A side with the indoor expansion valve <NUM> is connected to the liquid-refrigerant connection pipe <NUM>L, and the opposite side is connected to the gas-refrigerant connection pipe <NUM>G. The indoor expansion valve <NUM> is an electric valve that adjusts a flow rate of the refrigerant flowing through the indoor heat exchanger <NUM> while decompressing the refrigerant. The indoor heat exchanger <NUM> functions as a refrigerant evaporator to cool indoor air or functions as a refrigerant radiator to heat indoor air. An indoor fan <NUM> sucks the indoor air into the indoor unit <NUM>, exchanges heat with the refrigerant in the indoor heat exchanger <NUM>, and then supplies the indoor air as supply air to the room.

<FIG> is a diagram illustrating a state in which the outdoor unit <NUM> is removed from the air conditioner <NUM> illustrated in <FIG> and the refrigerant is collected. The liquid-side shutoff valve <NUM> and the gas-side shutoff valve <NUM> of the outdoor unit <NUM> are opened and connected to a refrigerant collector <NUM> via a manifold <NUM>. A cylinder <NUM> is connected to the refrigerant collector <NUM>. By operating the refrigerant collector <NUM>, the refrigerant remaining in the outdoor unit <NUM> can be sucked and collected in the cylinder <NUM>.

When the outdoor expansion valve <NUM>, the expansion valve <NUM>, and the expansion valve <NUM>, which are electric valves, are closed, the refrigerant remaining in the outdoor unit <NUM> cannot be completely collected. In particular, a relatively large amount of refrigerant trapped in a section <NUM> between the outdoor expansion valve <NUM> and the check valve <NUM> cannot be collected. In the present disclosure, the electric valves can be opened even in such a case.

<FIG> is a circuit diagram illustrating an example of a valve opening circuit <NUM> provided in a power source box <NUM>. The power source box <NUM> is provided in the outdoor unit <NUM>. In <FIG>, the valve opening circuit <NUM> includes an AC/DC switching power source <NUM>, a regulator <NUM>, a valve drive circuit <NUM>, a control unit <NUM>, and a valve opening switch <NUM>.

In a normal use state of the air conditioner <NUM>, a normal AC voltage is fed from a commercial AC power source <NUM> to the AC/DC switching power source <NUM>. The AC/DC switching power source <NUM> converts the AC voltage into a predetermined DC voltage V1, and outputs the DC voltage to a DC electric path <NUM>. The valve drive circuit <NUM> and the regulator <NUM> are connected to the DC electric path <NUM>. The power feed port <NUM> is connected to the DC electric path <NUM>. An actual form of the power feed port <NUM> is a terminal block or a connector.

The valve drive circuit <NUM> can open and close each electric valve (the outdoor expansion valve <NUM>, the expansion valve <NUM>, and the expansion valve <NUM>) on the basis of the DC voltage V1. The regulator <NUM> steps down the DC voltage V1 to a power source voltage V2 (= Vcc, V2 < V1) of the control unit <NUM>, and outputs the DC voltage V1 to a DC electric path <NUM>. The control unit <NUM> includes a microcomputer and operates on the basis of a computer program. A valve opening-closing signal can be given from outside to the control unit <NUM>. On the basis of the valve opening-closing signal, the control unit <NUM> gives a drive signal to the valve drive circuit <NUM> to open and close each electric valve. A valve opening command signal can be given from the valve opening switch <NUM> to the control unit <NUM>. The valve opening switch <NUM> is a manual switch and is operated by a service engineer. The power feed port <NUM> is not used when the air conditioner <NUM> is in the normal use state.

<FIG> is a circuit diagram of the valve opening circuit <NUM> in the power source box <NUM> in a state where connection with the commercial AC power source <NUM> is disconnected in order to remove the outdoor unit <NUM>. In the drawing, AC voltage is not fed to the AC/DC switching power source <NUM>. Here, a DC power source line <NUM> is connected to the power feed port <NUM> from an external power source (DC power source) <NUM> capable of outputting the DC voltage V1. As a result, even when the AC/DC switching power source <NUM> is not functioning, the DC voltage V1 can be generated in the DC electric path <NUM>. The regulator <NUM> steps down the DC voltage V1 to the power source voltage V2 of the control unit <NUM>, and outputs the DC voltage V1 to the DC electric path <NUM>.

From this state, when the service engineer operates the valve opening switch <NUM>, the control unit <NUM> transmits a valve opening signal to the valve drive circuit <NUM>. Upon receipt of the valve opening signal, the valve drive circuit <NUM> opens each electric valve (the outdoor expansion valve <NUM>, the expansion valve <NUM>, and the expansion valve <NUM>). The electric valves can thus be opened even after the outdoor unit <NUM> is disconnected from the commercial AC power source <NUM>.

Thereafter, the refrigerant remaining in the outdoor unit <NUM> can be collected by connecting the refrigerant collector <NUM> as illustrated in <FIG>.

<FIG> is a perspective view illustrating an example of an external appearance of the outdoor unit <NUM>. What can be seen in this drawing is a housing 1A and the outdoor heat exchanger <NUM> of the outdoor unit <NUM>. A cover 1C that is easily removed is attached to a part of an outer surface of the housing 1A.

<FIG> is a front view of the outdoor unit <NUM> with the cover 1C removed. When the cover 1C is removed, the power source box <NUM> and the inside thereof are exposed. In the power source box <NUM>, there is an external line terminal <NUM> as a source for connecting the commercial AC power source to the outdoor unit <NUM>. The power feed port <NUM> is disposed, for example, near the external line terminal <NUM>.

<FIG> is a circuit diagram illustrating another example of the valve opening circuit <NUM> provided in the power source box <NUM>. The difference from <FIG> is that there is no valve opening switch <NUM> provided in <FIG>, and instead, a signal can be sent from the AC/DC switching power source <NUM> to the control unit <NUM>. This signal is a signal notifying that the AC voltage is lost. Specifically, for example, by using a B contact of a relay, the contact is to be opened when there is an AC voltage, and the contact is to be closed when the AC voltage is lost. The contact being closed is a signal indicating that the AC voltage is lost. Since the operation of the valve opening circuit <NUM> according to a second embodiment is not different from the operation according to the first embodiment in the normal use state of the air conditioner <NUM>, the description thereof will be omitted.

<FIG> is a circuit diagram of the valve opening circuit <NUM> in the power source box <NUM> in a state where connection with the commercial AC power source <NUM> is disconnected in order to remove the outdoor unit <NUM>. In the drawing, AC voltage is not fed to the AC/DC switching power source <NUM>. This state is notified to the control unit <NUM>. Here, a DC power source line <NUM> is connected to the power feed port <NUM> from an external power source (DC power source) <NUM> capable of outputting the DC voltage V1. As a result, even when the AC/DC switching power source <NUM> is not functioning, the DC voltage V1 can be generated in the DC electric path <NUM>. The regulator <NUM> steps down the DC voltage V1 to the power source voltage V2 of the control unit <NUM>, and outputs the DC voltage V1 to the DC electric path <NUM>.

In this state, the control unit <NUM> receives a signal indicating that the AC voltage is lost from the AC/DC switching power source <NUM> although the voltage V2 is applied. As a result, the control unit <NUM> determines that the AC voltage is lost and the DC voltage V1 is fed from the external power source <NUM> to the power feed port <NUM>.

The control unit <NUM> thus determined sends a valve opening signal to the valve drive circuit <NUM>. Upon receipt of the valve opening signal, the valve drive circuit <NUM> opens each electric valve (the outdoor expansion valve <NUM>, the expansion valve <NUM>, and the expansion valve <NUM>). The electric valves can thus be opened even after the outdoor unit <NUM> is disconnected from the commercial AC power source <NUM>.

<FIG> is a diagram illustrating an example of a configuration in a case where the air conditioner <NUM> is of simultaneous cooling and heating.

In the drawing, from the outdoor unit <NUM> of simultaneous cooling and heating, a plurality of (here, four) flow path switching units <NUM> are connected via a high-pressure gas pipe <NUM>HG through which a high-pressure gas refrigerant flows, a low-pressure gas pipe <NUM>LG through which a low-pressure gas refrigerant flows, and a high-pressure liquid pipe <NUM>HL through which a high-pressure liquid refrigerant flows. The indoor unit <NUM> is connected to each of the flow path switching units <NUM>. The flow path switching units <NUM> and the indoor units <NUM> form a refrigerant circuit that shares the outdoor unit <NUM>. Note that, although four flow path switching units <NUM> and indoor units <NUM> are illustrated here, the number is merely an example for convenience of illustration. The flow path switching units <NUM> can be installed either outdoors or indoors.

Each of the flow path switching units <NUM> includes an electric valve <NUM> connected to the high-pressure gas pipe <NUM>HG, an electric valve <NUM> connected to the low-pressure gas pipe <NUM>LG, and an electric valve 14e connected to the high-pressure liquid pipe <NUM>HL.

The air conditioner <NUM> of simultaneous cooling and heating described above can cause any indoor unit <NUM> to perform an air conditioning (cooling or heating) operation as a use-side unit under the outdoor unit <NUM> common as a heat source-side unit. The flow path switching units <NUM> can also cause some of the indoor units <NUM> to perform cooling and other indoor units <NUM> to perform heating. Specifically, controlling opening and closing of the electric valves <NUM> and <NUM> enables the refrigerant flow path to be switched. Controlling an opening degree of the electric valve 14e as necessary enables adjustment of a flow rate of the refrigerant flowing through a heat exchanger in the indoor unit <NUM>. The electric valves <NUM>, <NUM>, and 14e in each of the flow path switching unit <NUM> can also be used as shutoff valves.

Since the flow path switching units <NUM> as described above also use an electric valve, there is a case where the refrigerant is trapped. It is therefore also conceivable to apply the valve opening circuit <NUM> as described above to the flow path switching unit <NUM> to release the trapped refrigerant.

In an intermediate unit of a system having a binary refrigerant circuit, such as a chiller system, if an electric valve is provided inside, there is also a case where a refrigerant is trapped. It is therefore also conceivable to apply the valve opening circuit <NUM> to the intermediate unit to release the trapped refrigerant.

Although the valves to be operated by the valve drive circuit <NUM> has been described as electric valves so far, the valve opening circuit <NUM> of the present disclosure is also applicable to opening and closing of an electromagnetic valve.

A summary of the above disclosure can be expressed in a generalized manner as follows.

A valve opening circuit of the present disclosure is a valve opening circuit <NUM> mounted on a heat pump device (air conditioner <NUM>) having a valve (outdoor expansion valve <NUM> or the like) on a refrigerant circuit <NUM>, the valve opening circuit including a DC electric path <NUM> to which a DC voltage generated from an AC voltage for normal use is applied, a valve drive circuit <NUM> that opens and closes the valve by using the DC voltage of the DC electric path <NUM>, a control unit <NUM> that acquires a control power source voltage based on the DC voltage of the DC electric path <NUM> and controls the valve drive circuit <NUM>, and a power feed port <NUM> connected to the DC electric path <NUM> and connectable to a DC power source line <NUM> provided from outside for emergency. The control unit <NUM> causes the valve drive circuit <NUM> to open the valve when the AC voltage is lost and the DC voltage is fed from the DC power source line <NUM> to the power feed port <NUM>.

When the heat pump device including the valve opening circuit <NUM> as described above is removed, even if the AC voltage of the commercial AC power source <NUM> is lost, the DC power source line <NUM> can be connected to the power feed port <NUM> to feed the DC voltage to the DC electric path <NUM>. By opening the valve in this state, the refrigerant remaining in the heat pump device can be reliably collected by the refrigerant collector <NUM>.

In the valve opening circuit <NUM>, the control unit <NUM> may open the valve when a condition that the AC voltage is lost and the DC voltage is fed from the DC power source line <NUM> to the power feed port <NUM> is satisfied.

In this case, when connection with the commercial AC power source <NUM> is disconnected from the heat pump device and the DC voltage is fed to the power feed port <NUM>, the valve can be automatically opened such that the refrigerant can be collected.

The valve opening circuit <NUM> can also include a valve opening switch <NUM>. The control unit <NUM> is to open the valve when the AC voltage is lost and the valve opening switch <NUM> is opened in a state where the DC power source line <NUM> is connected to the power feed port <NUM>.

In this case, the valve is not opened only by disconnecting the heat pump device from the commercial AC power source <NUM> and feeding the DC voltage to the power feed port <NUM>, but also by operating the valve opening switch <NUM>. Thus, the valve opening switch <NUM> can be operated after the refrigerant collector <NUM> is reliably connected to the heat pump device. This makes it possible to collect the refrigerant while avoiding leakage of the refrigerant into the atmosphere as much as possible.

Disclosed is a heat pump device (air conditioner <NUM>) having a valve (outdoor expansion valve <NUM> or the like) on a refrigerant circuit <NUM>, the heat pump device including a DC electric path <NUM> to which a DC voltage generated from an AC voltage for normal use is applied, a valve drive circuit <NUM> that opens and closes the valve by using the DC voltage of the DC electric path <NUM>, a control unit <NUM> that acquires a control power source voltage based on the DC voltage of the DC electric path <NUM> and controls the valve drive circuit <NUM>, and a power feed port <NUM> connected to the DC electric path <NUM> and connectable to a DC power source line <NUM> provided from outside for emergency. The control unit <NUM> causes the valve drive circuit <NUM> to open the valve when the AC voltage is lost and the DC voltage is fed from the DC power source line <NUM> to the power feed port <NUM>.

With the heat pump device as described above, when the heat pump device is removed, even if the AC voltage of the commercial AC power source <NUM> is lost, the DC power source line <NUM> can be connected to the power feed port <NUM> to feed the DC voltage to the DC electric path <NUM>. By opening the valve in this state, the refrigerant remaining in the heat pump device can be reliably collected by the refrigerant collector <NUM>.

The heat pump device preferably include a power source box <NUM>, in which the power feed port <NUM> is provided in the power source box <NUM>.

In this case, the power feed port <NUM> that is not used except when the heat pump device is removed can be accommodated in the power source box <NUM> without being unnecessarily exposed.

The power source box <NUM> is preferably provided at a position to be exposed in a state where a cover 1C on a part of an outer surface of a housing 1A of the heat pump device is removed.

In this case, when the cover 1C is removed, the power source box <NUM> is exposed, and the DC power source line <NUM> can be connected to the power feed port <NUM>.

The power source box <NUM> is preferably provided inside with an external line terminal <NUM> that feeds the AC voltage, and the power feed port <NUM> is preferably provided near the external line terminal.

In this case, after the power source box <NUM> is exposed and a cable for feeding the commercial AC power source <NUM> to the external line terminal <NUM> is removed, the DC power source line <NUM> can be connected to the power feed port <NUM> in that state, and therefore there is no waste in operation.

The valve is preferably provided in a pipe line from a heat exchanger (outdoor heat exchanger <NUM>) to a liquid pipe (liquid-refrigerant connection pipe <NUM>L).

Claim 1:
A valve opening circuit (<NUM>) mounted on a heat pump device including a valve on a refrigerant circuit, the valve opening circuit comprising:
a DC electric path (<NUM>) to which a DC voltage generated from an AC voltage for normal use is applied;
a valve drive circuit (<NUM>) that opens and closes the valve by using the DC voltage of the DC electric path (<NUM>);
a control unit (<NUM>) that acquires a control power source voltage based on the DC voltage of the DC electric path (<NUM>) and controls the valve drive circuit (<NUM>); and
a power feed port (<NUM>) connected to the DC electric path (<NUM>) and connectable to a DC power source line (<NUM>) provided from outside for emergency, wherein
the control unit (<NUM>) causes the valve drive circuit (<NUM>) to open the valve when the AC voltage is lost and the DC voltage is fed from the DC power source line (<NUM>) to the power feed port (<NUM>).