Heat medium circulation device

Abstract

A heat medium circulation device 100 of the present disclosure including: a refrigerant circuit 110 which is formed by annularly connecting a compressor 111, a use-side heat exchanger 112, an expanding device 113 and a heat source-side heat exchanger 114 to one another; and a mechanical chamber 130 in which a portion of at least the refrigerant circuit 110 and a control device 120 are accommodated, in which flammable refrigerant is used as working fluid, wherein the heat medium circulation device 100 further includes an open / close mechanism 140 which opens such that an interior of the mechanical chamber 130 is vented into the outdoor atmosphere when the flammable refrigerant leaks into the mechanical chamber 130. Therefore, it is possible to lower the ignition risk when the flammable refrigerant leaks while securing energy saving performance and noise barrier performance.

Description

[TECHNICAL FIELD]

[0001] The present invention relates to a heat medium circulation device.[BACKGROUND TECHNIQUE]

[0002] EP 2 896 897 A1 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.

[0003] JP 2002-115939 A 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.[SUMMARY OF THE INVENTION][PROBLEM TO BE SOLVED BY THE INVENTION]

[0004] The present invention provides a heat medium circulation device according to claim 1 which enhances safety when flammable refrigerant leaks while securing energy saving performance and noise barrier performance.[MEANS FOR SOLVING THE PROBLEM]

[0005] A heat medium circulation device of the invention includes, i.a., 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.[EFFECT OF THE INVENTION]

[0006] 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.[BRIEF DESCRIPTION OF THE DRAWINGS]

[0007] Fig. 1 is a configuration diagram of a heat medium circulation device according to an embodiment of the present invention; Fig. 2 is a refrigerant circuit diagram of the heat medium circulation device of the embodiment; Fig. 3 is a pressure-enthalpy diagram of the heat medium circulation device of the embodiment (P-h diagram); Fig. 4 is a configuration diagram of a control device of the embodiment; Fig. 5 is a configuration diagram of an open / close mechanism of the embodiment; Fig. 6 is a diagram showing operating action when refrigerant leaks into a mechanical chamber in the embodiment; and Fig. 7 is a flowchart for explaining detection of leakage of refrigerant of the heat medium circulation device of the embodiment and for explaining control action of the open / close mechanism. [MODE FOR CARRYING OUT THE INVENTION]

[0008] 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.

[0009] 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.

[0010] The embodiment will be described below using Figs. 1 to 7.[1-1. Configuration][1-1-1. Configuration of heat medium circulation device]

[0011] In Fig. 1, a heat medium circulation device 100 includes a refrigerant circuit 110, a control device 120, a mechanical chamber 130 in which at least a portion of the refrigerant circuit 110 and the control device 120 are accommodated, and an open / close mechanism 140.

[0012] The refrigerant circuit will be described using Fig. 2.

[0013] The refrigerant circuit 110 is a vapor compression type refrigeration cycle. The refrigerant circuit 110 is formed by sequentially connecting a compressor 111, a use-side heat exchanger 112, an expanding device 113 and a heat source-side heat exchanger 114 to one another through a pipe 116. In the refrigerant circuit 110, propane which is flammable refrigerant is used as refrigerant.

[0014] A four-way valve 115 is provided in the refrigerant circuit 110. The four-way valve 115 switches between heating operation for producing warm water and cooling operation for producing cold water.

[0015] 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 112. The heat medium is heated and cooled by exchanging heat with refrigerant.

[0016] In Fig. 2, 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.

[0017] Variation of a state of refrigerant in the heating operation and the cooling operation will be described using Fig. 3.

[0018] At the time of the heating operation, high pressure refrigerant (point a) discharged out from the compressor 111 flows into the use-side heat exchanger 112 through the four-way valve 115, and the high pressure refrigerant radiates heat to heat medium which flows through the use-side heat exchanger 112. The high pressure refrigerant (point b) after it radiates heat in the use-side heat exchanger 112 is decompressed and expanded by the expanding device 113 and then, the refrigerant flows into the heat source-side heat exchanger 114. Low pressure refrigerant (point c) which flows into the heat source-side heat exchanger 114 absorbs heat from outside air and is vaporized, and again returns to a suction side (point d) of the compressor 111 through the four-way valve 115.

[0019] On the other hand, at the time of the cooling operation, high pressure refrigerant (point a) discharged out from the compressor 111 flows into the heat source-side heat exchanger 114 through the four-way valve 115 and radiates heat to outside air in the heat source-side heat exchanger 114. The high pressure refrigerant (point b) after it radiates heat in the heat source-side heat exchanger 114 is decompressed and expanded by the expanding device 113 and then, the high pressure refrigerant flows into the use-side heat exchanger 112. The low pressure refrigerant (point c) which flows into the use-side heat exchanger 112 absorbs heat from heat medium which flows through the use-side heat exchanger 112 and is vaporized, and again returns to the suction side (point d) of the compressor 111 through the four-way valve 115.

[0020] The control device 120 is provided in a casing of the heat medium circulation device 100. The control device 120 controls the number of rotations of the compressor 111, a throttling amount of the expanding device 113, the switching operation of the four-way valve 115 and the like such that efficiency of the vapor compression type refrigeration cycle is enhanced. The control device 120 also performs control to operate the open / close mechanism 140 when flammable refrigerant in the mechanical chamber 130 leaks.[1-1-2. Configuration of control device]

[0021] Next, a configuration of the control device 120 will be described using Fig. 4. The control device 120 is composed of a controller 121, a user interface 122 and a refrigerant concentration sensor 123. The controller 121 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 122. The refrigerant concentration sensor 123 detects concentration of flammable gas in the mechanical chamber.[1-1-3. Configuration of open / close mechanism]

[0022] A configuration of the open / close mechanism 140 will be described using Fig. 5. The open / close mechanism 140 is composed of an opening 141, a flap 142 and a driving device 143. The flap 142 closes the opening 141. The driving device 143 opens and closes the flap 142. The open / close mechanism 140 is placed in the mechanical chamber 130 at a position lower than the control device 120. The driving device 143 is connected to the control device 120.[1-2. Action]

[0023] Action and effect of the heat medium circulation device 100 having the above-described configuration will be described below.[1-2-1. Cooling and heating operation actions]

[0024] The controller 121 carries out the heating operation or the cooling operation based on input information of the user interface 122.[1-2-2. Discharging action of refrigerant and operation action when refrigerant leaks]

[0025] Operation action when refrigerant leaks into the mechanical chamber 130 will be described based on Fig. 6.

[0026] Flammable refrigerant which leaks into the mechanical chamber 130 is discharged out into outdoor atmosphere from the open / close mechanism 140, and Fig. 6 schematically shows this flow of the flammable refrigerant.

[0027] For example, the pipe 116 in the refrigerant circuit 110 is cracking and flammable refrigerant leaks into the mechanical chamber 130. 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 143 is driven by instructions of the controller 121. If the flap 142 is operated in its opening direction by the servomotor, the interior of the mechanical chamber 130 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 140 which is placed at a low position in the mechanical chamber 130. As the flammable refrigerant is discharged outdoors, inner pressure of the mechanical chamber 130 is lowered. As a result, a pressure difference between the inner pressure of the mechanical chamber 130 and the outdoor atmosphere is generated, outside air is newly incorporated from the opening 141, and the discharging action of the flammable refrigerant is promoted.

[0028] Action at this time will be described in more detail using a flowchart shown in Fig. 7.

[0029] By a user's operation of the user interface 122, start of the heating operation or the cooling operation is instructed (step S1). By this instruction, the control device 120 operates the compressor 111, controls the number of rotation of the compressor 111, and adjust an opening degree of the expanding device 113 (step S2). Next, the control device 120 detects refrigerant concentration Cr in the mechanical chamber 130 by the refrigerant concentration sensor 123 (step S3). Then, the control device 120 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).

[0030] When the refrigerant concentration Cr is smaller than the refrigerant concentration Ca (NO in step S4), the control device 120 determines that refrigerant does not leak into the mechanical chamber 130, and continues the operation.

[0031] 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 120 determines that refrigerant gas leaks into the mechanical chamber 130, and stops the operation of the compressor 111 (step S5). Next, the servomotor in the driving device 143 is driven by the instruction of the controller 121, the flap 142 is operated in the opening direction and the open / close mechanism 140 is opened. According to this, the interior of the mechanical chamber 130 is vented into the outdoor atmosphere (step S6).[1-3. Effects and the like]

[0032] The heat medium circulation device 100 includes the refrigerant circuit 110, the control device 120, the mechanical chamber 130 and the open / close mechanism 140. The refrigerant circuit 110 is a vapor compression type refrigeration cycle of flammable refrigerant. The refrigerant circuit 110 is formed by annularly connecting the compressor 111, the use-side heat exchanger 112, the expanding device 113 and the heat source-side heat exchanger 114 to one another. The heat medium circulation 100 device includes the open / close mechanism 140 which opens such that the interior of the mechanical chamber 130 is vented into the outdoor atmosphere when the flammable refrigerant leaks into the mechanical chamber 130.

[0033] According to this, when flammable refrigerant leaks into the mechanical chamber 130, 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 140. Doing so, refrigerant density in the mechanical chamber 130 is lowered. Since the flammable refrigerant is discharged into the outdoor atmosphere, the inner pressure in the mechanical chamber 130 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 130 is further lowered.

[0034] Hence, safety when the flammable refrigerant leaks into the mechanical chamber 130 is enhanced. Since the open / close mechanism 140 closes when refrigerant does not leak, it is possible to prevent outside air from entering into the mechanical chamber 130. Further, heat radiation from the refrigerant circuit 110 when the system is operated is suppressed, and enhancement of energy saving performance can be expected. In addition, when the open / close mechanism 140 is always opened, noise in the mechanical chamber 130 leaks out, but when refrigerant does not leak, the open / close mechanism 140 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.

[0035] The open / close mechanism 140 may be placed at a position lower than the control device 120 in the casing including at least the mechanical chamber 130 as in the embodiment.

[0036] 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 140 located at a position lower than the control device 120 without staying in the control device 120 and according to this, density of the flammable refrigerant in the vicinity of the control device 120 is lowered. Hence, safety when flammable refrigerant leaks is enhanced.

[0037] The refrigerant concentration sensor 123 and the control device 120 may be provided in the mechanical chamber 130, and when a detection value of the refrigerant concentration sensor 123 becomes equal to or higher than a predetermined value, the control device 120 may determine that refrigerant leaks from the refrigerant circuit 110 as in the embodiment.

[0038] According to this, it is possible to detect leakage with a simple configuration.

[0039] The flammable refrigerant may be R32, mixed refrigerant including 70% or more R32 by weight, propane or mixed refrigerant including propane.(OtherEmbodiments)

[0040] 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.

[0041] The other embodiments will be described below.

[0042] In the previous embodiment, a cooling and heating hot water supply system was described as one example of the heat medium circulation device 100. The heat medium circulation device 100 is not limited only if it can cool or heat the heat medium. Therefore, the heat medium circulation device 100 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 100, 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 100. If the cold / warm water chiller is used as the heat medium circulation device 100, 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.

[0043] In the previous embodiments, the refrigerant concentration sensor 123 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 130 from the refrigerant circuit 110. Therefore, the leakage detecting sensor is not limited to the refrigerant concentration sensor 123. However, if the refrigerant concentration sensor 123 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 110 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 110, it is possible to detect the leakage only by an existing sensor, and it is unnecessary to newly provide a sensor.

[0044] In the previous embodiment, the flap 142 was described as one example of the open / close mechanism 140. The open / close mechanism 140 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 140 is not limited to the flap 142. However, if the flap 142 is used as the open / close mechanism 140, it is possible to detect the leakage of refrigerant with a simple configuration. The open / close mechanism 140 may be a blind composed of a plurality of slats. If the blind is employed as the open / close mechanism 140, 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.

[0045] In the previous embodiment, the servomotor was described as one example of the driving device 143. However, it is only necessary that the driving device 143 can operate the flap 142 in its opening direction. Therefore, the driving device 143 is not limited to the servomotor. However, if the servomotor is used as the driving device 143, 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 143. If the hydraulic device is employed as the driving device 143, the control device 120 is not required in a driving section. Therefore, it is possible to further lower the ignition risk in the mechanical chamber 130.[INDUSTRIAL APPLICABILITY]

[0046] The present invention can be applied to a heat medium circulation device in which flammable refrigerant may leak into a heat medium circuit. More specifically, the present invention can be applied to a warm water supply heater, a professional-use chiller and the like.[EXPLANATION OF SYMBOLS]

[0047] 100heat medium circulation device 110refrigerant circuit 111compressor 112use-side heat exchanger 113expanding device 114heat source-side heat exchanger 115four-way valve 116pipe 120control device 121controller 122user interface 123refrigerant concentration sensor 130mechanical chamber 140open / close mechanism 141opening 142flap 143driving device

Claims

1. A heat medium circulation device (100) comprising: a refrigerant circuit (110) which is formed by annularly connecting a compressor (111), a use-side heat exchanger (112), an expanding device (113) and a heat source-side heat exchanger (114) to one another; and a mechanical chamber (130) in which a portion of at least the refrigerant circuit (110) and a control device (120) are accommodated, the mechanical chamber (130) also comprising a refrigerant concentration sensor (123) and an open / close mechanism (140) placed at a low position in the mechanical chamber (130), in which flammable refrigerant having a density greater than that of air is used as working fluid, characterized in that the open / close mechanism (140) is placed at a position lower than the control device (120), the control device (120) being configured to operate a flap (142) to an opening direction by driving a servomotor, and in that the open / close mechanism (140) is opened by operation of the flap (142) when a detection value of the refrigerant concentration sensor (123) becomes equal to or higher than a predetermined value.

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