Heat transfer fluid circulation device

Abstract

Heat transfer fluid circulation device comprising an outdoor unit (1), wherein the outdoor unit (1) comprises: a refrigerant circuit (10) connecting a compressor (5), a user-side heat exchanger (6), a pressure reducing device (7) and a heat source-side heat exchanger (8) to circulate refrigerant; a heat transfer circuit (12) which is connected to the user-side heat exchanger (6); an air blower (11) for expelling an airflow to exchange heat with the heat source-side heat exchanger (8); and a control substrate (16) for controlling the operation of the compressor (5), the pressure reducing device (7) and the air blower (11); wherein an interior of the outdoor unit (1) is divided by a partition plate (20), one side of the partition plate (20) is an outside air connection chamber (19), another side of the partition plate (20) is an inner machine chamber (18), the heat source-side heat exchanger (8) and the air blower (11) are placed in the outside air connection chamber (19), and the compressor (5), the user-side heat exchanger (6) and the pressure reducing device (7) are placed in the internal machine chamber (18), wherein the control substrate (16) is housed in a power supply housing (21) and the power supply housing (21) is placed above the air blower (11), characterized by the fact that an interior of the power supply housing (21) is not connected to the inner machine chamber (18), the refrigerant is a flammable refrigerant with a specific gravity greater than that of air, and the control substrate (16) is placed in the outside air connection chamber (19).

Description

[TECHNICAL FIELD]

[0001] The present invention relates to a heat pump-type heat transfer fluid circulation device that uses refrigerants. [STATE OF THE ART]

[0002] A device or system is known as a heat pump-type heat transfer fluid circulation device or heat pump hot water supply system in which an inverter for controlling a compressor or a radiator plate for radiating the heat of the inverter is arranged above an air blower.

[0003] According to JP 2005-083692 A, for example, the radiator plate is arranged in an air blow circuit.

[0004] In JP 4899510 B2, a control device is arranged above an air blower circuit.

[0005] JP 2007-212025 A shows a heat pump hot water supply device comprising a control board consisting of a refrigerant circuit control board and a hot water supply circuit control board, which are arranged separately. [SUMMARY OF THE INVENTION][PROBLEM TO BE SOLVED BY THE INVENTION]

[0006] Due to increased environmental awareness, it is currently necessary, particularly in Europe, to use refrigerants with a low global warming potential (GWP). Carbon dioxide (R744) and flammable propane (R290) are used as low-GWP refrigerants. However, in the case of carbon dioxide, the water inlet temperature in the heat pump hot water supply system is high, resulting in low efficiency. Furthermore, carbon dioxide requires high pressure resistance, thus increasing component costs. Additionally, the efficiency of carbon dioxide during cooling operation is only about 60% that of refrigerant R32. Therefore, propane is more suitable than carbon dioxide for a heat transfer fluid circulation system that heats or cools a room by heating or cooling a heat transfer fluid.

[0007] Propane is a flammable refrigerant, and it is important to ensure safety in the event of a refrigerant leak. Since an electrical potential is applied to a control substrate or control unit that controls a compressor, ensuring safety is particularly critical in the event of a refrigerant leak.

[0008] Therefore, an objective of the present invention is to solve this conventional problem and to provide a safe, durable and cost-effective heat transfer fluid circulation device using a flammable refrigerant. [Means to solve the problem]

[0009] A heat transfer fluid circulation device with an outdoor unit, the outdoor unit comprising: a refrigerant circuit connecting a compressor, a user-side heat exchanger, a pressure reducing device, and a heat source-side heat exchanger to circulate refrigerant; a heat transfer fluid circuit connected to the user-side heat exchanger; an air blower for expelling an airflow to exchange heat with the heat source-side heat exchanger; and a control substrate for controlling the operation of the compressor, the pressure reducing device, and the air blower;wherein an interior of the outdoor unit is divided by a partition plate, one side of the partition plate being an outdoor air connection chamber, the other side of the partition plate being an indoor machine chamber, the heat source-side heat exchanger and the air blower being placed in the outdoor air connection chamber, and the compressor, the user-side heat exchanger, and the pressure reducing device being placed in the indoor machine chamber, wherein the control substrate is housed in a power supply enclosure, and the power supply enclosure is arranged above the air blower, such that the interior of the power supply enclosure is not in communication with the indoor machine chamber, the refrigerant is a flammable refrigerant having a specific gravity greater than that of air, and the control substrate is placed in the outdoor air connection chamber. [Impact of the invention]

[0010] According to the present invention, a flammable refrigerant with a higher specific gravity than air is used as the refrigerant. The control substrate is housed in the power supply casing, which is positioned above the air blower. The interior of the power supply casing is not in contact with the internal machine chamber. This prevents flammable refrigerant from entering the power supply casing containing the control substrate. In this way, a heat transfer fluid circulation device is provided, enabling the use of a safe heat pump. [BRIEF DESCRIPTION OF THE DRAWINGS] Fig. Figure 1 is a pipe circuit diagram of a heat transfer fluid circulation device according to a first embodiment of the present invention; Fig. Figures 2 show the configuration of an outdoor unit of the heat transfer fluid circulation device; Fig. Figures 3 show the configuration of an outdoor unit of a heat transfer fluid circulation device according to a second embodiment of the invention; and Fig. Figure 4 shows the airflow of a power supply enclosure in the outdoor unit. [MODE FOR EXECUTING THE INVENTION]

[0011] In a heat transfer fluid circulation device according to a first embodiment of the present invention, a flammable refrigerant having a higher specific gravity than air is used as the refrigerant, a control substrate is housed in a power supply housing, the power supply housing is placed above an air blower, and the interior of the power supply housing is not in contact with the internal machine chamber.

[0012] According to this embodiment, it is possible to prevent the flammable refrigerant from entering the power supply housing, which contains a control substrate. Therefore, it is possible to provide a heat transfer device with a safe heat pump.

[0013] In a second embodiment, in the heat transfer fluid circulation device of the first embodiment, the control substrate includes a heat radiation section, and the power supply housing includes a ventilation duct for introducing air from the outside of the outdoor unit into the power supply housing and an outlet section for expelling air from the power supply housing to the outside of the power supply housing.

[0014] According to this embodiment, air located outside the outdoor unit can be directed through the ventilation duct into the power supply housing to cool the control substrate, thereby lowering its temperature. This prevents component deterioration and allows the heat transfer circulation device to operate with consistent performance over an extended period.

[0015] In the heat transfer fluid circulation device of the first or second embodiment, the control substrate is arranged in an outside air connection chamber.

[0016] According to this feature, since there is no control substrate above the internal machine chamber, the flammable refrigerant, even if it escapes from a refrigerant circuit, does not flow towards the control substrate. This makes it possible to provide a safe heat transfer fluid circulation device. [FORMS OF EXECUTION]

[0017] The following describes embodiments of the present invention with reference to the drawings. The invention is not limited to these embodiments. (First embodiment)

[0018] Fig. Figure 1 is a pipe circuit diagram of a heat transfer fluid circulation device according to a first embodiment of the present invention.

[0019] The heat transfer fluid circulation device of this embodiment comprises an outdoor unit 1, an intermediate transfer device 2, and an outdoor radiator 4. The heat transfer fluid circulation device heats or cools a heat transfer fluid such as circulating water or antifreeze. The outdoor unit 1 and the intermediate transfer device 2 are connected to each other by a heat transfer fluid line 3. The intermediate transfer device 2 and the outdoor radiator 4 are connected to each other by the heat transfer fluid line 3.

[0020] Although in Fig. 1. Where a panel-type external heating radiator 4 is shown, such as an underfloor heating system, the external radiator 4 can also be a household radiator such as a fan convector, which includes a panel radiator or a fan 11. The external radiator 4 can be a hot air blower or a hot water radiator used in a factory.

[0021] The outdoor unit 1 heats or cools water, producing hot or cold water. The hot or cold water flows through the heat transfer line 3 and is directed to the outdoor radiator 4, where it heats or cools a living space in which the outdoor radiator 4 is located. In this way, the outdoor radiator 4 heats or cools an area or room. The outdoor unit 1 produces hot or cold water for heating or cooling an area or room.

[0022] The outdoor unit 1 is equipped with a compressor 5, a water-to-refrigerant heat exchanger 6, an expansion valve 7, an air-to-refrigerant heat exchanger 8, and a four-way valve 9. The compressor 5 compresses and circulates refrigerant. The water-to-refrigerant heat exchanger 6 exchanges heat between a heat transfer fluid, such as water or antifreeze, and the refrigerant circulated by the compressor 5. The expansion valve 7 is a pressure reducing device. The four-way valve 9 switches between heating and cooling operation of the heat transfer fluid.

[0023] The refrigerant circuit 10 connects the compressor 5, the four-way valve 9, the water-refrigerant heat exchanger 6, a pressure reducing device 7 and the air-refrigerant heat exchanger 8 in a ring-shaped configuration, thus forming a closed circuit, and the refrigerant circulates through the refrigerant circuit 10.

[0024] The water-refrigerant heat exchanger 6 consists of a refrigerant line 6a, through which the refrigerant flows, and a heat transfer line 6b, through which the heat transfer fluid flows. The water-refrigerant heat exchanger 6 is made of copper or stainless steel tubing, which has high thermal conductivity. The water-refrigerant heat exchanger 6 exchanges heat between the refrigerant and the heat transfer fluid and heats or cools a heat transfer fluid, such as water or antifreeze, using the refrigerant.

[0025] In this embodiment, the water-refrigerant heat exchanger 6 corresponds to a user-side heat exchanger and the air-refrigerant heat exchanger 8 to a heat source-side heat exchanger.

[0026] The blower 11 conveys air to the air-refrigerant heat exchanger 8 and increases the heat exchange capacity of the air-refrigerant heat exchanger 8.

[0027] On the other hand, the heat transfer fluid is circulated through a heat transfer circuit 12, and the circulating heat transfer fluid exchanges heat with the refrigerant in the water-refrigerant heat exchanger 6. A circulation pump 13 forces the heat transfer fluid to circulate in the heat transfer circuit 12, and the circulation pump 13 is located upstream of the water-refrigerant heat exchanger 6.

[0028] The intermediate transfer device 2 includes a flow sensor 14, which is provided in series with the heat transfer line 3, and an expansion absorption tank 15, which is placed parallel to the heat transfer line 3. The expansion absorption tank 15 is of a hermetic type.

[0029] A pair of connection openings 3a connects the heat transfer line 3 and the heat transfer circuit 12.

[0030] Control components that control various types of actuators and various types of sensors (e.g., temperature sensors) of the outdoor unit 1 are arranged in a control substrate 16. A user performs actions and various types of setting operations in the outdoor unit 1 and the intermediate relay device 2 via a remote control 17.

[0031] The Fig. Figure 2 shows a configuration of the outdoor unit of the heat transfer fluid circulation device, wherein Fig. 2(a) a front view of an interior view, Fig. 2(b) is a side view of the interior view and Fig. 2(c) is a top view of the interior view.

[0032] The outdoor unit 1 is composed of a base plate 1a and a cover 1b, which form a housing, and in the outdoor unit 1 an inner machine chamber 18 and an outside air connection chamber 19 are formed.

[0033] The interior of the external unit 1 is divided by a partition plate 20, wherein on one side of the partition plate 20 is the external air connection chamber 19 and on the other side of the partition plate 20 is the internal machine chamber 18.

[0034] The air-to-refrigerant heat exchanger 8 and the air blower 11 are located in the outside air connection chamber 19. The compressor 5, the water-to-refrigerant heat exchanger 6, the pressure reducing device 7, the circulation pump 13, and the four-way valve 9 are located in the inside machine chamber 18.

[0035] The base plate 1a is provided at the lowest section of the outdoor unit 1, and the compressor 5 is located in the indoor machine chamber 18 on the right side of the base plate 1a.

[0036] The water-refrigerant heat exchanger 6 is a plate heat exchanger and is located on the right rear side of the base plate 1a. The pair of connection ports 3a, which are connected to the water-refrigerant heat exchanger 6, extend from the rear of the housing to the outside. The heat transfer line 3 is connected to the connection ports 3a.

[0037] Although in the Fig. 2 where a plate heat exchanger is shown, the heat exchanger can also have a double-pipe configuration, provided that heat exchange can take place between the refrigerant and the heat transfer medium.

[0038] The expansion valve 7, which is a pressure reducing device, and the four-way valve 9, which switches between heating and cooling modes of the heat transfer fluid, are located near the compressor 5. The expansion valve 7 and the four-way valve 9, together with the compressor 5, form the refrigerant circuit 10.

[0039] The air-to-refrigerant heat exchanger 8 is located on the left rear side of the base plate 1a. The air-to-refrigerant heat exchanger 8 is connected to the expansion valve 7 and the four-way valve 9 by a pipe extending from the outermost right section of the air-to-refrigerant heat exchanger 8.

[0040] The air blower 11, which circulates air, is positioned opposite the air-refrigerant heat exchanger 8. The air blower 11 enhances the heat exchange capacity of the air-refrigerant heat exchanger 8.

[0041] The circulation pump 13 is located below the water-refrigerant heat exchanger 6 and circulates the heat transfer fluid in the heat transfer circuit 12. The circulation pump 13 is connected to the water-refrigerant heat exchanger 6 and the connection openings 3a.

[0042] The circulation pump 13 circulates the heat transfer fluid in the heat transfer fluid circuit 12. The circulation pump 13 can be provided in the intermediate transfer device 2.

[0043] The inner machine chamber 18 and the outer air connection chamber 19 are separated by the partition plate 20. The partition plate 20 is provided between a front face of the housing and the air-to-refrigerant heat exchanger 8, which is located behind the housing.

[0044] The control substrate 16 is arranged above the partition plate 20, and the control substrate 16 is provided in the power supply housing 21, which is arranged above the outside air connection chamber 19.

[0045] The control substrate 16 comprises an IPM (Intelligent Power Module) 16a, a cooling fin 16b, and an electrolytic capacitor 16c. The IPM 16a operates the compressor 5 via an inverter. The cooling fin 16b cools the IPM 16a. The electrolytic capacitor 16c operates the inverter efficiently. The IPM 16a and the electrolytic capacitor 16c are heat dissipation sections. The cooling fin 16b projects downwards from the power supply housing 21 and is cooled by the air blower 11.

[0046] The power supply housing 21 is formed from a lower section of the power supply housing 21a and a power supply housing cover 21b to form an essentially hexahedral housing body. According to the power supply housing 21, the power supply housing cover 21b covers the control substrate 16 after the control substrate 16 is placed on the lower section 21a of the power supply housing 21. The control substrate 16 is thus covered by the power supply housing 21.

[0047] Connecting wires of various types of actuators and sensors are connected to the control substrate 16. These connecting wires seal the connecting wire feedthrough holes of the power supply housing 21, so that outside air does not flow into the power supply housing 21, or almost no outside air flows into the power supply housing 21.

[0048] A section of the power supply housing 21 is located slightly above the inner machine chamber 18, but the power supply housing 21 is completely separated from the inner machine chamber 18. The control substrate 16 is located above the outside air connection chamber 19.

[0049] The refrigerant used in refrigerant circuit 10 is a flammable refrigerant that has a specific gravity greater than that of air, and the refrigerant is, for example, propane (R290).

[0050] The operation of the heat transfer fluid circulation device is described using the drawings.

[0051] In Fig. 1. The four-way valve 9 is in a state in which hot water is generated; first, the hot water generation process is described.

[0052] When compressor 5 is operated, refrigerant is compressed to a high pressure and expelled. The refrigerant flows through the four-way valve 9 and is directed to the water-refrigerant heat exchanger 6. The refrigerant exchanges heat with the low-temperature water, which flows through the heat transfer circuit 12 in the water-refrigerant heat exchanger 6 due to the power of the circulation pump 13, and the refrigerant releases heat. This heats the low-temperature water, making it high-temperature water. The high-temperature water is then directed from the heat transfer line 3, via the intermediate transfer device 2, to the outdoor radiator 4. This heats the living space.

[0053] The refrigerant exiting the water-refrigerant heat exchanger 6 is decompressed and expanded by the expansion valve 7. The refrigerant is then directed to the air-refrigerant heat exchanger 8, which is the evaporator. The refrigerant exchanges heat with air that is passed through the air blower 11, and as the refrigerant flows through the air-refrigerant heat exchanger 8, it evaporates and becomes gaseous.

[0054] The gaseous refrigerant flows through the four-way valve 9, is drawn into the compressor 5 and compressed again.

[0055] Currently, propane (R290) is used as a refrigerant. Propane is a natural refrigerant with an extremely low GWP (Global Warming Potential), namely only 3, and will not be subject to regulation in the future.

[0056] Propane is used in air conditioning systems. Propane differs significantly from R32 (GWP: 675), which will be subject to chlorofluorocarbon regulations in the future, because propane is an environmentally friendly refrigerant.

[0057] Furthermore, unlike carbon dioxide gas (GWP: 1), which has a low GWP and extremely low cooling capacity, propane has the same heating and cooling capacity as chlorofluorocarbon-based refrigerants. Therefore, there is a high probability that propane will become the market standard in the future.

[0058] However, propane is a flammable refrigerant.

[0059] There is a possibility that the propane refrigerant will leak from the refrigerant circuit 10, and the propane refrigerant tends to leak if any component of the refrigerant circuit 10 ruptures.

[0060] The control substrates 16 have many parts to which electrical potential is applied, and it is important to ensure safety.

[0061] In this respect, the control substrate 16 is located in the power supply housing 21, the six surfaces of which are covered. This power supply housing 21 is not located above the internal machine chamber 18, which contains the refrigerant circuit 10, such as the compressor 5, but rather above the outside air connection chamber 19, through which outside air flows. This prevents refrigerant from entering the power supply housing 21.

[0062] In particular, the specific gravity of propane is 1.56, which is heavier than that of air; and if propane escapes, it remains in the lower part of the outdoor unit 1; this arrangement is more advantageous than an arrangement in which it is placed above the outdoor unit 1.

[0063] However, if the refrigerant circuit 10 ruptures during operation, there is a possibility that the propane refrigerant will escape violently and reach an upper section of the outdoor unit 1. Since the control substrate 16 is located in the power supply housing 21, whose six surfaces are covered, it is possible to prevent flammable refrigerant from entering the power supply housing 21.

[0064] Therefore, even when using flammable refrigerant, it is possible to provide a heat transfer fluid circulation device using a safe heat pump.

[0065] The control substrate 16 is positioned above the outdoor unit 1 and is covered by the power supply housing 21. This makes it possible to implement a heat transfer fluid circulation device with a comparatively simple arrangement and to increase safety cost-effectively.

[0066] Although the heat transfer fluid heating operation for hot water production is described, heat transfer fluid cooling operation is also possible by switching the four-way valve 9 to change the refrigerant flow direction. The behavior in the event of a refrigerant leak is the same in this case, and safety can be ensured. (Second embodiment)

[0067] The Fig. Figure 3 shows the arrangement of an outdoor unit of a heat transfer fluid circulation device according to a second embodiment of the invention, wherein Fig. 3(a) a front view of an interior view, Fig. 3(b) is a side view of the interior view and Fig. 3(c) is a top view of the interior. Since the same symbols are assigned to the same functional elements as in the first embodiment, their description is omitted, and mainly those sections that differ from those of the first embodiment are described.

[0068] The control substrate 16 is placed above a partition plate 20 and is provided in a power supply housing 21, which is placed above an outside air connection chamber 19.

[0069] The control substrate 16 comprises an IPM (Intelligent Power Module) 16a, a cooling fin 16b, and an electrolytic capacitor 16c. The IPM 16a operates the compressor 5 via an inverter. The cooling fin 16b cools the IPM 16a. The electrolytic capacitor 16c operates the inverter efficiently. The IPM 16a and the electrolytic capacitor 16c are heat dissipation sections. The cooling fin 16b projects downwards from the power supply housing 21 and is cooled by the air blower 11.

[0070] The power supply housing 21 is formed from a lower section of the power supply housing 21a and a power supply housing cover 21b to form an essentially hexahedral housing body. According to the power supply housing 21, the power supply housing cover 21b covers the control substrate 16 after the control substrate 16 is placed on the lower section 21a of the power supply housing 21. The control substrate 16 is thus covered by the power supply housing 21.

[0071] Connecting wires of various types of actuators and sensors are connected to the control substrate 16. These connecting wires seal the connecting wire feedthrough holes of the power supply housing 21, so that outside air does not flow into the power supply housing 21, or almost no outside air flows into the power supply housing 21.

[0072] A ventilation duct 22 is provided in the power supply housing 21 on the side of an inner machine chamber 18. The ventilation duct 22 is attached to the power supply housing 21. A power supply housing inlet opening 21c is provided in the power supply housing 21, opposite the ventilation duct 22.

[0073] The ventilation duct 22 is connected to a right-hand panel 23 of the outdoor unit 1. A right-hand panel inlet opening 23a is provided in the power supply housing 21, which is opposite the ventilation duct 22 of the right-hand panel 23.

[0074] A power supply housing outlet opening 21d is provided in a front surface of the power supply housing 21, which is opposite the outside air connection chamber 19.

[0075] The process for generating hot water is also described here.

[0076] When the remote control 17 is activated and the heat transfer fluid circulation device is put into operation, the compressor 5 is driven. Refrigerant, compressed to high pressure by the compressor 5 and expelled, passes through the four-way valve 9 and is directed to the water-refrigerant heat exchanger 6. The refrigerant exchanges heat with the low-temperature water, which flows through the heat transfer fluid circuit 12 by the power of the circulation pump 13, and the refrigerant releases heat. This heats the low-temperature water, raising it to a high-temperature level. The water then passes through the heat transfer pipe 3 to the intermediate heat exchanger 2 and from there to the external radiator 4, thus heating the living space.

[0077] Refrigerant exiting the water-refrigerant heat exchanger 6 is decompressed and expanded by the expansion valve 7. The refrigerant is then directed to the air-refrigerant heat exchanger 8, which is an evaporator. The refrigerant exchanges heat with the air supplied by the air blower 11, and as the refrigerant passes through the air-refrigerant heat exchanger 8, it evaporates and becomes gaseous.

[0078] This gaseous refrigerant passes through the four-way valve 9, is drawn in by the compressor 5 and compressed again.

[0079] At this point, the temperatures of the IPM 16a and the electrolytic capacitor 16c rise. The cooling fin 16b projects downwards from the power supply box 21 and is cooled by the air blower 11. However, in some cases, this cooling measure is insufficient. In particular, operation to generate low-temperature water is carried out at high ambient air temperatures, and the water-refrigerant heat exchanger 6 acts as a condenser. Therefore, the air-refrigerant heat exchanger 8 is brought into a high-temperature state, and even if the air-refrigerant heat exchanger 8 is cooled by the air blower 11, the cooling fin 16b may not be sufficiently cooled in some cases.

[0080] Since the control substrate 16 in particular is covered by the power supply housing 21, the heat generated in the control substrate 16 cannot escape, and there is a tendency for the power supply housing 21 to be brought into a state of high temperature.

[0081] In general, the lifespan of a capacitor used in an inverter depends on the temperature, and temperature affects its lifespan. A general Arrhenius equation applies to the relationship between temperature and lifespan. For every 10°C increase in temperature, the evaporation rate of the electrolyte solution in the capacitor doubles, and the lifespan is halved; this is why it is also known as the "10°C double time rule".

[0082] A typical electrolytic capacitor is often specified as "105 °C - 2,000 hours". However, at 2,000 hours, the capacitor's lifespan, assuming ten hours of operation per day for 150 days, is only one year and four months, which is less than two years.

[0083] On the other hand, in an environment of 85 °C, which is 20 °C lower than in the previous case, the lifespan of the electrolytic capacitor is 8,000 hours, four times that of the previous case. If the temperature is 10 °C lower, i.e., 75 °C, the lifespan of the electrolytic capacitor is 16,000 hours. With a lifespan of 16,000 hours, the electrolytic capacitor can be operated for more than ten years without any problems, even if it is operated for ten hours a day and 150 days a year.

[0084] This is just one example, but other control components exhibit the same tendency. Reducing the temperature of the control substrate 16 is extremely important for reliability and quality.

[0085] On the other hand, it is possible to generate an airflow 24. Air is drawn into the air blower 11, which is operated safely during operation. The air is directed through the right plate inlet opening 23a and through the ventilation duct 22. Then the air is directed through the inlet 21c of the power supply housing 21 and through the control substrate 16 and the outlet 21d of the power supply housing.

[0086] Fig. Figure 4 shows the airflow 24.

[0087] The airflow 24 can cool the control substrate 16, thereby lowering its temperature. This allows the heat transfer circulation device to maintain high reliability for extended periods.

[0088] Furthermore, even if flammable refrigerant were to escape from the refrigerant circuit 10 at this time, the six surfaces of the power supply housing 21 are covered, and the ventilation duct 22, located in the indoor machine chamber 18, has no opening facing the indoor machine chamber 18. Therefore, the right-hand plate inlet opening 23a and the outlet opening 21d of the power supply housing, which have these openings, are only in contact with the outside of the outdoor unit 1. Therefore, they do not come into contact with flammable refrigerant.

[0089] Therefore, safety is not compromised even when using flammable refrigerant, and it is possible to provide a safe heat transfer fluid circulation device. [INDUSTRIAL APPLICABILITY]

[0090] As described above, the present invention is applied to a heat transfer fluid circulation device that heats or cools a heat transfer fluid in a refrigerant circuit, and the invention is suitable for air conditioning systems for private or institutional use. [EXPLANATION OF SYMBOLS] 1 outdoor unit 1a Base plate 1b Cover 2 Intermediate transmission device 3 Heat transfer pipe 3a Connection openings 4 external radiators 5 Compressor 6 Water-refrigerant heat exchangers (utility-side heat exchanger) 6a Refrigerant line 6b Heat transfer pipe 7 Expansion valve (pressure reducing device) 8 Air-to-refrigerant heat exchangers (heat source-side heat exchangers) 9 Four-way valve 10 Refrigerant circuit 11 air blowers 12 Heat transfer fluid circuit 13 Circulation pump 14 Flow sensor 15 expansion absorption tanks 16 Control substrate 16a IPM (Heat Emission Section) 16b Cooling fin 16c Electrolytic capacitor (heat dissipation section) 17 Remote control 18 Inside engine room 19 Outside air connection chamber 20 separating plates 21 power supply housings 21a lower section of the power supply housing 21b Power supply housing cover 21c Inlet opening of the power supply housing 21d Outlet opening of the power supply housing 22 ventilation duct 23 right plate 23a right plate inlet opening 24 Airflow QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2005-083692 A

[0003] JP 4899510 B2

[0004] JP 2007-212025 A

[0005]

Claims

Heat transfer fluid circulation device comprising an outdoor unit (1), the outdoor unit (1) comprising: a refrigerant circuit (10) connecting a compressor (5), a user-side heat exchanger (6), a pressure reducing device (7) and a heat source-side heat exchanger (8) to circulate refrigerant; a heat transfer fluid circuit (12) connected to the user-side heat exchanger (6); an air blower (11) for expelling an airflow to exchange heat with the heat source-side heat exchanger (8); and a control substrate (16) for controlling the operation of the compressor (5), the pressure reducing device (7) and the air blower (11); wherein an interior of the outdoor unit (1) is divided by a partition plate (20), one side of the partition plate (20) is an outside air connection chamber (19), another side of the partition plate (20) is an indoor machine chamber (18),the heat source-side heat exchanger (8) and the air blower (11) are placed in the outside air connection chamber (19), and the compressor (5), the service-side heat exchanger (6) and the pressure reducing device (7) are placed in the indoor machine chamber (18), wherein the control substrate (16) is housed in a power supply housing (21) and the power supply housing (21) is placed above the air blower (11), characterized in that an interior space of the power supply housing (21) is not connected to the indoor machine chamber (18), the refrigerant is a flammable refrigerant with a specific gravity greater than that of air, and the control substrate (16) is placed in the outside air connection chamber (19). Heat transfer medium circulation device according to claim 1, wherein the control substrate (16) comprises heat radiation sections (16a, 16c), the power supply housing (21) includes a ventilation duct (22) for introducing air from outside the outdoor unit (1) into the power supply housing (21) and an outlet through which the air in the power supply housing (21) is discharged from the power supply housing (21) to the outside. Heat transfer medium circulation device according to claim 1 or 2, wherein a housing is formed by a base plate (1a) provided on the lowest section of the outdoor unit (1) and a cover (1b), the internal machine chamber (18) is located on the right side of the base plate (1a), and the outdoor air connection chamber (19) is located on the left side of the base plate (1a), and the refrigerant is propane. Heat transfer medium circulation device according to one of claims 1 to 3, wherein a section of the power supply housing (21) is located above the inner machine chamber (18).

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