Patent Description:
<CIT> discloses a heat medium circulation device in which flammable refrigerant which leaks out from a refrigeration cycle circuit is easily discharged out from a casing. This heat medium circulation device includes a refrigeration circuit, a mechanical chamber, an induction hole through which outside air is introduced, and a blowing hole which is brought into communication with a blowing circuit from the mechanical chamber.

<CIT> discloses a heat pump system using a flammable refrigerant as working fluid, making use of a sensor to detect flammable refrigerant leaks, in order to avoid the risk of explosion or the like.

The present invention provides a heat medium circulation device according to claim <NUM> which enhances safety when flammable refrigerant leaks while securing energy saving performance and noise barrier performance.

A heat medium circulation device of the invention includes,
i. , a refrigerant circuit in which a compressor, a use-side heat exchanger, an expanding device and a heat source-side heat exchanger are annularly connected to one another, and a mechanical chamber in which at least a portion of the refrigerant circuit and a control device are accommodated, flammable refrigerant is used as working fluid, and the heat medium circulation device further includes an open/close mechanism which opens such that an interior of the mechanical chamber is vented into the outdoor atmosphere when flammable refrigerant leaks into the mechanical chamber.

According to the heat medium circulation device of the invention, safety when flammable refrigerant leaks into the mechanical chamber is enhanced. When refrigerant does not leak, since the open/close mechanism is closed, it is possible to prevent outside air from entering the mechanical chamber. Therefore, heat radiation from the refrigerant circuit when the system is operated is suppressed, and it is possible to expect enhancement of the energy saving performance. In addition, when the open/close mechanism is always opened, noise in the mechanical chamber leaks outside, but when refrigerant does not leak, the open/close mechanism is closed. Therefore, the noise barrier performance is enhanced, and it is possible to secure air permeability while suppressing, to the minimum, increase in noise according to the present invention.

An embodiment will be described in detail below with reference to the drawings. Description which is described in detail more than necessary will be omitted in some cases. For example, detailed description of already well known matters, or redundant description of substantially the same configuration will be omitted in some cases. This is for preventing the following description from becoming redundant more than necessary, and for making it easy for a person skilled in the art to understand the present disclosure.

The accompanying drawing and the following description are provided so that the person skilled in the art can sufficiently understand the present disclosure, and it is not intended that they limit the subject matter described in claims.

The embodiment will be described below using <FIG>.

In <FIG>, a heat medium circulation device <NUM> includes a refrigerant circuit <NUM>, a control device <NUM>, a mechanical chamber <NUM> in which at least a portion of the refrigerant circuit <NUM> and the control device <NUM> are accommodated, and an open/close mechanism <NUM>.

The refrigerant circuit will be described using <FIG>.

The refrigerant circuit <NUM> is a vapor compression type refrigeration cycle. The refrigerant circuit <NUM> is formed by sequentially connecting a compressor <NUM>, a use-side heat exchanger <NUM>, an expanding device <NUM> and a heat source-side heat exchanger <NUM> to one another through a pipe <NUM>. In the refrigerant circuit <NUM>, propane which is flammable refrigerant is used as refrigerant.

A four-way valve <NUM> is provided in the refrigerant circuit <NUM>. The four-way valve <NUM> switches between heating operation for producing warm water and cooling operation for producing cold water.

Heat medium using water or antifreeze liquid which is transferred out from a heat medium circuit placed indoors flows into the use-side heat exchanger <NUM>. The heat medium is heated and cooled by exchanging heat with refrigerant.

In <FIG>, solid arrows show a flowing direction of refrigerant at the time of the heating operation, and broken arrows show the flowing direction of refrigerant at the time of the cooling operation.

Variation of a state of refrigerant in the heating operation and the cooling operation will be described using <FIG>.

At the time of the heating operation, high pressure refrigerant (point a) discharged out from the compressor <NUM> flows into the use-side heat exchanger <NUM> through the four-way valve <NUM>, and the high pressure refrigerant radiates heat to heat medium which flows through the use-side heat exchanger <NUM>. The high pressure refrigerant (point b) after it radiates heat in the use-side heat exchanger <NUM> is decompressed and expanded by the expanding device <NUM> and then, the refrigerant flows into the heat source-side heat exchanger <NUM>. Low pressure refrigerant (point c) which flows into the heat source-side heat exchanger <NUM> absorbs heat from outside air and is vaporized, and again returns to a suction side (point d) of the compressor <NUM> through the four-way valve <NUM>.

On the other hand, at the time of the cooling operation, high pressure refrigerant (point a) discharged out from the compressor <NUM> flows into the heat source-side heat exchanger <NUM> through the four-way valve <NUM> and radiates heat to outside air in the heat source-side heat exchanger <NUM>. The high pressure refrigerant (point b) after it radiates heat in the heat source-side heat exchanger <NUM> is decompressed and expanded by the expanding device <NUM> and then, the high pressure refrigerant flows into the use-side heat exchanger <NUM>. The low pressure refrigerant (point c) which flows into the use-side heat exchanger <NUM> absorbs heat from heat medium which flows through the use-side heat exchanger <NUM> and is vaporized, and again returns to the suction side (point d) of the compressor <NUM> through the four-way valve <NUM>.

The control device <NUM> is provided in a casing of the heat medium circulation device <NUM>. The control device <NUM> controls the number of rotations of the compressor <NUM>, a throttling amount of the expanding device <NUM>, the switching operation of the four-way valve <NUM> and the like such that efficiency of the vapor compression type refrigeration cycle is enhanced. The control device <NUM> also performs control to operate the open/close mechanism <NUM> when flammable refrigerant in the mechanical chamber <NUM> leaks.

Next, a configuration of the control device <NUM> will be described using <FIG>. The control device <NUM> is composed of a controller <NUM>, a user interface <NUM> and a refrigerant concentration sensor <NUM>. The controller <NUM> is provided with a microcomputer, a memory and the like. Operation and shutdown of the device and setting of temperature of heat medium which is produced are input through the user interface <NUM>. The refrigerant concentration sensor <NUM> detects concentration of flammable gas in the mechanical chamber.

A configuration of the open/close mechanism <NUM> will be described using <FIG>. The open/close mechanism <NUM> is composed of an opening <NUM>, a flap <NUM> and a driving device <NUM>. The flap <NUM> closes the opening <NUM>. The driving device <NUM> opens and closes the flap <NUM>. The open/close mechanism <NUM> is placed in the mechanical chamber <NUM> at a position lower than the control device <NUM>. The driving device <NUM> is connected to the control device <NUM>.

Action and effect of the heat medium circulation device <NUM> having the above-described configuration will be described below.

The controller <NUM> carries out the heating operation or the cooling operation based on input information of the user interface <NUM>.

Operation action when refrigerant leaks into the mechanical chamber <NUM> will be described based on <FIG>.

Flammable refrigerant which leaks into the mechanical chamber <NUM> is discharged out into outdoor atmosphere from the open/close mechanism <NUM>, and <FIG> schematically shows this flow of the flammable refrigerant.

For example, the pipe <NUM> in the refrigerant circuit <NUM> is cracking and flammable refrigerant leaks into the mechanical chamber <NUM>. When it is detected that the leaked refrigerant has concentration which is equal to or greater than a preset refrigerant value, a servomotor in the driving device <NUM> is driven by instructions of the controller <NUM>. If the flap <NUM> is operated in its opening direction by the servomotor, the interior of the mechanical chamber <NUM> is vented into the outdoor atmosphere. Here, flammable refrigerant having density greater than that of air moves downward due to a density difference between itself and air, and the flammable refrigerant is gradually discharged out from the open/close mechanism <NUM> which is placed at a low position in the mechanical chamber <NUM>. As the flammable refrigerant is discharged outdoors, inner pressure of the mechanical chamber <NUM> is lowered. As a result, a pressure difference between the inner pressure of the mechanical chamber <NUM> and the outdoor atmosphere is generated, outside air is newly incorporated from the opening <NUM>, and the discharging action of the flammable refrigerant is promoted.

Action at this time will be described in more detail using a flowchart shown in <FIG>.

By a user's operation of the user interface <NUM>, start of the heating operation or the cooling operation is instructed (step S1). By this instruction, the control device <NUM> operates the compressor <NUM>, controls the number of rotation of the compressor <NUM>, and adjust an opening degree of the expanding device <NUM> (step S2). Next, the control device <NUM> detects refrigerant concentration Cr in the mechanical chamber <NUM> by the refrigerant concentration sensor <NUM> (step S3). Then, the control device <NUM> compares preset refrigerant concentrations Ca and Cr with each other, and determines whether the refrigerant concentration Cr is equal to or greater than the refrigerant concentration Ca (step S4).

When the refrigerant concentration Cr is smaller than the refrigerant concentration Ca (NO in step S4), the control device <NUM> determines that refrigerant does not leak into the mechanical chamber <NUM>, and continues the operation.

On the other hand, when the refrigerant concentration Cr is equal to or greater than the refrigerant concentration Ca (YES in step S4), the control device <NUM> determines that refrigerant gas leaks into the mechanical chamber <NUM>, and stops the operation of the compressor <NUM> (step S5). Next, the servomotor in the driving device <NUM> is driven by the instruction of the controller <NUM>, the flap <NUM> is operated in the opening direction and the open/close mechanism <NUM> is opened. According to this, the interior of the mechanical chamber <NUM> is vented into the outdoor atmosphere (step S6).

The heat medium circulation device <NUM> includes the refrigerant circuit <NUM>, the control device <NUM>, the mechanical chamber <NUM> and the open/close mechanism <NUM>. The refrigerant circuit <NUM> is a vapor compression type refrigeration cycle of flammable refrigerant. The refrigerant circuit <NUM> is formed by annularly connecting the compressor <NUM>, the use-side heat exchanger <NUM>, the expanding device <NUM> and the heat source-side heat exchanger <NUM> to one another. The heat medium circulation <NUM> device includes the open/close mechanism <NUM> which opens such that the interior of the mechanical chamber <NUM> is vented into the outdoor atmosphere when the flammable refrigerant leaks into the mechanical chamber <NUM>.

According to this, when flammable refrigerant leaks into the mechanical chamber <NUM>, the flammable refrigerant having density greater than that of air moves downward due to a density difference between the flammable refrigerant and air, and the flammable refrigerant is discharged out from the open/close mechanism <NUM>. Doing so, refrigerant density in the mechanical chamber <NUM> is lowered. Since the flammable refrigerant is discharged into the outdoor atmosphere, the inner pressure in the mechanical chamber <NUM> is lowered, outside air is incorporated due to the pressure difference between the inner pressure and the outdoor atmosphere, and the discharging action of the flammable refrigerant is promoted. Doing so, the refrigerant density in the mechanical chamber <NUM> is further lowered.

Hence, safety when the flammable refrigerant leaks into the mechanical chamber <NUM> is enhanced. Since the open/close mechanism <NUM> closes when refrigerant does not leak, it is possible to prevent outside air from entering into the mechanical chamber <NUM>. Further, heat radiation from the refrigerant circuit <NUM> when the system is operated is suppressed, and enhancement of energy saving performance can be expected. In addition, when the open/close mechanism <NUM> is always opened, noise in the mechanical chamber <NUM> leaks out, but when refrigerant does not leak, the open/close mechanism <NUM> is closed. Hence, the noise barrier performance is enhanced, and it is possible to suppress the increase of noise to the minimum while securing the air permeability by the present invention.

The open/close mechanism <NUM> may be placed at a position lower than the control device <NUM> in the casing including at least the mechanical chamber <NUM> as in the embodiment.

According to this, the flammable refrigerant having specific gravity greater than that of air moves to a position lower than the leakage location, the flammable refrigerant is discharged by the open/close mechanism <NUM> located at a position lower than the control device <NUM> without staying in the control device <NUM> and according to this, density of the flammable refrigerant in the vicinity of the control device <NUM> is lowered. Hence, safety when flammable refrigerant leaks is enhanced.

The refrigerant concentration sensor <NUM> and the control device <NUM> may be provided in the mechanical chamber <NUM>, and when a detection value of the refrigerant concentration sensor <NUM> becomes equal to or higher than a predetermined value, the control device <NUM> may determine that refrigerant leaks from the refrigerant circuit <NUM> as in the embodiment.

According to this, it is possible to detect leakage with a simple configuration.

The flammable refrigerant may be R32, mixed refrigerant including <NUM>% or more R32 by weight, propane or mixed refrigerant including propane.

The present embodiment has been described as an example of technique disclosed in the present application as described above. However, the technique in the present disclosure is not limited to this, and the invention can be applied also to embodiments in which change, replacement, addition, omission and the like are carried out. It is also possible to combine the configuration elements described in the above embodiment to create a new embodiment.

The other embodiments will be described below.

In the previous embodiment, a cooling and heating hot water supply system was described as one example of the heat medium circulation device <NUM>. The heat medium circulation device <NUM> is not limited only if it can cool or heat the heat medium. Therefore, the heat medium circulation device <NUM> is not limited to the cooling and heating hot water supply system. However, if the cooling and heating hot water supply system is used as the heat medium circulation device <NUM>, it is possible to meet the annual heat demand of housing. A cold/warm water chiller may be used as the heat medium circulation device <NUM>. If the cold/warm water chiller is used as the heat medium circulation device <NUM>, it is possible to cope with heating/cooling thermal load used in a factory. Hence, it is possible to enhance the energy saving performance of a factory.

In the previous embodiments, the refrigerant concentration sensor <NUM> was described as one example of a leakage detecting sensor. The leakage detecting sensor is not limited only if it can determine that refrigerant leaks into the mechanical chamber <NUM> from the refrigerant circuit <NUM>. Therefore, the leakage detecting sensor is not limited to the refrigerant concentration sensor <NUM>. However, if the refrigerant concentration sensor <NUM> is used as the leakage detecting sensor, it is possible to detect the leakage of refrigerant with a simple configuration. It is also possible that a sensor used for controlling the refrigerant circuit <NUM> is used as the leakage detecting sensor, and to estimate leakage of flammable refrigerant from a value of the sensor. If the refrigerant leakage is estimated by the value of the sensor used for controlling the refrigerant circuit <NUM>, it is possible to detect the leakage only by an existing sensor, and it is unnecessary to newly provide a sensor.

In the previous embodiment, the flap <NUM> was described as one example of the open/close mechanism <NUM>. The open/close mechanism <NUM> is not limited only if it closes when leakage of flammable refrigerant is not detected, and it opens when leakage of the refrigerant is detected. Therefore, the open/close mechanism <NUM> is not limited to the flap <NUM>. However, if the flap <NUM> is used as the open/close mechanism <NUM>, it is possible to detect the leakage of refrigerant with a simple configuration. The open/close mechanism <NUM> may be a blind composed of a plurality of slats. If the blind is employed as the open/close mechanism <NUM>, it is possible to reduce a motion range in size with respect to an opening area, and it is unnecessary to limit an installation position of the system.

In the previous embodiment, the servomotor was described as one example of the driving device <NUM>. However, it is only necessary that the driving device <NUM> can operate the flap <NUM> in its opening direction. Therefore, the driving device <NUM> is not limited to the servomotor. However, if the servomotor is used as the driving device <NUM>, the servomotor is excellent in terms of position-controlling performance, and the servomotor can be driven in an electricity-saving manner. Therefore, it is possible to satisfy both the controlling performance and the energy saving performance. It is also possible to use a hydraulic device as the driving device <NUM>. If the hydraulic device is employed as the driving device <NUM>, the control device <NUM> is not required in a driving section. Therefore, it is possible to further lower the ignition risk in the mechanical chamber <NUM>.

Claim 1:
A heat medium circulation device (<NUM>) comprising:
a refrigerant circuit (<NUM>) which is formed by annularly connecting a compressor (<NUM>), a use-side heat exchanger (<NUM>), an expanding device (<NUM>) and a heat source-side heat exchanger (<NUM>) to one another; and
a mechanical chamber (<NUM>) in which a portion of at least the refrigerant circuit (<NUM>) and a control device (<NUM>) are accommodated, the mechanical chamber (<NUM>) also comprising a refrigerant concentration sensor (<NUM>) and an open/close mechanism (<NUM>) placed at a low position in the mechanical chamber (<NUM>),
in which flammable refrigerant having a density greater than that of air is used as working fluid,
characterized in that the open/close mechanism (<NUM>) is placed at a position lower than the control device (<NUM>), the control device (<NUM>) being configured to operate a flap (<NUM>) to an opening direction by driving a servomotor, and
in that the open/close mechanism (<NUM>) is opened by operation of the flap (<NUM>) when a detection value of the refrigerant concentration sensor (<NUM>) becomes equal to or higher than a predetermined value.