Patent Application
20220404038
The present disclosure relates to an air conditioning system in which a gas burner is disposed upstream side of a heat exchanger.
Conventionally, a furnace-equipped duct split-type air conditioner in which an indoor unit is installed in an attic, a basement, a garage, a closet, or the like is widely known. For example, in an air conditioner as disclosed in Patent Literature 1 (JP 2015-145764 A), a heat exchanger constituting a part of a refrigerant circuit and a gas burner are disposed in the same duct, and the gas burner is located upstream of the heat exchanger.
In a case where a refrigerant flowing through the refrigerant circuit is a flammable refrigerant, in preparation for a refrigerant leak from a connection portion connecting the heat exchanger and a refrigerant connection pipe, a leakage detection sensor detects the refrigerant leak early for safety, and thorough measures are taken. The present application aims to further improve safety.
An air conditioning system according to a first aspect includes a burner unit and a heat exchanger unit. The burner unit includes a burner and a first casing. The first casing houses the burner, and is provided with an air inlet. The heat exchange unit includes a heat exchanger, a second casing, and a connection portion. A flammable refrigerant passes through the heat exchanger. The second casing houses the heat exchanger. The connection portion is connected to a refrigerant connection pipe extending from a heat source unit. The first casing has a first surface. The second casing is disposed to overlap a part of the first surface. The first surface has a first portion that overlaps the second casing and a second portion that does not overlap the second casing. The connection portion is disposed on the second casing to be projected onto the second portion of the first casing. The air inlet is provided in a surface that is other than the second portion and is at least one of a plurality of surfaces adjacent to the first surface.
(1) Configuration of Air Conditioning System 1
Here, the air conditioning system 1 is installed in a two-story house 200. In the house 200, rooms 201 and 202 are provided on the first floor, and rooms 203 and 204 are provided on the second floor. The house 200 is provided with a basement 205.
As illustrated in
The duct 19 includes an air supply duct 19a and a return duct 19b. The air supply duct 19a is branched into the rooms 201 to 204, and is connected to ventilation ports 201a to 204a of the respective rooms 201 to 204. The return duct 19b is branched into the rooms 201 to 204, and is connected to ventilation ports 201b to 204b of the respective rooms 201 to 204.
A substantially equal volume of air to a volume of air supplied from the utilization-side unit 50 to the rooms 201 to 204 through the air supply duct 19a returns to the utilization-side unit 50 through the return duct 19b.
For convenience of description, the utilization-side unit 50, the heat source-side unit 30, and the refrigerant connection pipes 36 and 37 are collectively referred to as an air conditioner 3.
In
The air conditioning system 1 further includes a gas furnace unit 20 as a separate heat source from the heat pump unit 60. The gas furnace unit 20 heats the room by heat generated by gas combustion.
The air conditioning system combining the heat pump unit 60 and the gas furnace unit 20 can perform the heat pump heating operation by the heat pump unit 60 at a relatively high outside air temperature, and perform the heating operation by the gas furnace unit 20 at a low outside air temperature. It is also possible to provide a safer device when using a flammable refrigerant having a small global warming potential (GWP).
Therefore, the air conditioning system having a low global warming effect can be used not only in an area where the outside air temperature is relatively high but also in an area where the outside air temperature is low.
For convenience of description, a unit including the utilization-side unit 50 and the gas furnace unit 20 is referred to as the indoor unit 2.
(2) Indoor Unit 2
The first casing 11 has a first surface 111. The second casing 41 is disposed to overlap a part of the first surface 111. As a result, the first surface 111 has a first portion 111a that overlaps the second casing 41 and a second portion 111b that does not overlap the second casing 41.
As illustrated in
The second casing 41 has a surface 411 adjacent to the second portion 111b. The surface 411 is provided with a liquid pipe connection portion 38 and a gas pipe connection portion 39. The liquid pipe connection portion 38 is connected to the liquid refrigerant connection pipe 36 extending from the heat source-side unit 30. The gas pipe connection portion 39 is connected to the gas refrigerant connection pipe 37 extending from the heat source-side unit 30.
The liquid pipe connection portion 38 and the gas pipe connection portion 39 protrude outward to such an extent as to be projected onto the second portion 111b.
An air inlet 11a including a plurality of openings is provided in the first casing 11. The surface on which the air inlet 11a is provided is a surface that is other than the second portion 111b and is at least one of a plurality of surfaces adjacent to the first surface 111. Here, being adjacent means being in a positional relationship of forming a corner.
Here, the plurality of surfaces adjacent to the first surface 111 will be described. When the surface 411 on which the liquid pipe connection portion 38 and the gas pipe connection portion 39 are disposed is viewed as a front surface, the surface facing the first surface 111 of the first casing 11 is defined as a second surface 112.
Next, the surface located between the first surface 111 and the second surface 112 and forming a front surface is defined as a third surface 113.
The surfaces adjacent to both the first surface 111 and the third surface 113 are defined as a fourth surface 114 and a fifth surface 115, respectively.
In the present embodiment, as illustrated in
As illustrated in
The indoor temperature sensor 14 detects a temperature (hereinafter referred to as an indoor temperature Tr) of air in the air inlet 11a of the first casing 11. The indoor temperature sensor 14 may be provided in one of the rooms 201 to 204 instead of the indoor unit 2.
A gas sensor 90 is installed in the indoor unit 2. When a refrigerant leaks from the refrigerant circuit 61 of the heat pump unit 60, the gas sensor 90 detects leaking refrigerant, outputs a detection signal to a controller 80, and the indoor fan 24 is driven to agitate the leaking refrigerant. The refrigerant sealed in the refrigerant circuit 61 is a flammable refrigerant, and R32 is used in the present embodiment.
(3) Details of Heat Pump Unit 60
In the heat pump unit 60 of the air conditioner 3, the utilization-side unit 50 and the heat source-side unit 30 are connected to each other via the refrigerant connection pipes 36 and 37 to constitute the refrigerant circuit 61. The refrigerant connection pipes 36 and 37 are refrigerant pipes constructed on-site when the air conditioner 3 is installed.
(3-1) Utilization-Side Unit 50
The utilization-side unit 50 is installed in the basement 205 of the house 200. Note that an installation location of the utilization-side unit 50 is not necessarily the basement 205, and may be installed at another indoor place. The utilization-side unit 50 includes an indoor heat exchanger 40 as a refrigerant radiator that heats air through heat radiation from a refrigerant, and an indoor expansion valve 42.
(3-1-1) Indoor Heat Exchanger 40
The indoor heat exchanger 40 is disposed on a most leeward side of a ventilation path from the air inlet 11a to an air outlet 44 in the first casing 11.
(3-1-2) Indoor Expansion Valve 42
During a cooling operation, the indoor expansion valve 42 decompresses the refrigerant circulating in the refrigerant circuit 61, and causes the refrigerant to flow through the indoor heat exchanger 40. Here, the indoor expansion valve 42 is a decompression valve connected to a liquid side of the indoor heat exchanger 40.
(3-2) Heat Source-Side Unit 30
The heat source-side unit 30 is installed outside of the house 200. The heat source-side unit 30 includes a compressor 31, an outdoor heat exchanger 33, an outdoor expansion valve 34, and a four-way switching valve 32.
(3-2-1) Compressor 31
The compressor 31 is a hermetic compressor that houses, in a casing, a compression element (not shown) and a compressor motor 31a that rotationally drives the compression element.
The compressor motor 31a is supplied with electric power via an inverter device (not shown), and allows an operating capacity to be varied by changing a frequency (a number of revolutions) of the inverter device.
(3-2-2) Outdoor Heat Exchanger 33
The outdoor heat exchanger 33 functions as a refrigerant evaporator that evaporates the refrigerant. Near the outdoor heat exchanger 33, an outdoor fan 35 that sends outdoor air to the outdoor heat exchanger 33 is provided. In the outdoor fan 35, a fan 35a is rotationally driven by an outdoor fan motor 35b.
(3-2-3) Outdoor Expansion Valve 34
During a heating operation, the outdoor expansion valve 34 decompresses the refrigerant circulating in the refrigerant circuit 61, and causes the refrigerant to flow through the outdoor heat exchanger 33. Here, the outdoor expansion valve 34 is a decompression valve connected to a liquid side of the outdoor heat exchanger 33. The heat source-side unit 30 is provided with an outdoor temperature sensor 83 that detects a temperature of outdoor air outside of the house 200 where the heat source-side unit 30 is disposed (hereinafter referred to as an outside air temperature Ta).
(3-2-4) Four-Way Switching Valve 32
The four-way switching valve 32 is a valve to switch a refrigerant flow direction. During a cooling operation, the four-way switching valve 32 connects a discharge side of the compressor 31 and a gas side of the outdoor heat exchanger 33 to each other, and also connects a suction side of the compressor 31 and a gas refrigerant connection pipe 37 to each other (a cooling operation state: see a solid line of the four-way switching valve 32 in
During a heating operation, the four-way switching valve 32 connects a discharge side of the compressor 31 and the gas refrigerant connection pipe 37 to each other, and also connects a suction side of the compressor 31 and a gas side of the outdoor heat exchanger 33 to each other (a heating operation state: see a broken line of the four-way switching valve 32 in
(4) Details of Gas Furnace Unit 20
The gas furnace unit 20 is provided in the first casing 11 located below the second casing 41. The gas furnace unit 20 is a gas combustion heating device, and includes a combustion unit 10, a fuel gas valve 12, a furnace fan 13, a furnace heat exchanger 15, an air supply pipe 16, and an exhaust pipe 17.
(4-1) Combustion Unit 10
The combustion unit 10 is a device that obtains high-temperature combustion gas by burning mixed gas of fuel gas and air with a gas burner or the like (not shown).
(4-2) Fuel Gas Valve 12
The fuel gas valve 12 is configured by an electromagnetic valve or the like controlled to open and close, and is provided in a fuel gas supply pipe 18 extending from outside of the first casing 11 to the combustion unit 10. As the fuel gas, natural gas, petroleum gas, and the like are used.
(4-3) Furnace Fan 13
The furnace fan 13 is a fan that generates an air flow of taking in air into the combustion unit 10 through the air supply pipe 16, then sending the air to the furnace heat exchanger 15, and discharging from the exhaust pipe 17. In the furnace fan 13, a fan 13a is rotationally driven by a furnace fan motor 13b.
(4-4) Furnace Heat Exchanger 15
The furnace heat exchanger 15 is a heat exchanger that heats air by heat radiation from the combustion gas obtained in the combustion unit 10, and functions as a separate heat source radiator that heats air by heat radiation from a heat source (here, heat from gas combustion) that is separate from the heat pump unit 60.
The furnace heat exchanger 15 is disposed on a windward side of the indoor heat exchanger 40 in the ventilation path from the air inlet 11a to the air outlet 44 in the first casing 11.
(4-5) Indoor Fan 24
The indoor fan 24 takes air into the first casing 11, and supplies air heated by the indoor heat exchanger 40 of the heat pump unit 60 or the furnace heat exchanger 15 of the gas furnace unit 20 into the rooms 201 to 204.
In the ventilation path from the air inlet 11a to the air outlet 44 in the first casing 11, the indoor fan 24 is disposed on a windward side of both the indoor heat exchanger 40 and the furnace heat exchanger 15. The indoor fan 24 includes a fan 24a and an indoor fan motor 24b that rotationally drives the fan 24a
(5) Controller 80
The utilization-side unit 50 is equipped with an indoor-side control board 81 that controls an operation of each part of the utilization-side unit 50. The heat source-side unit 30 is equipped with an outdoor-side control board 82 that controls an operation of each part of the heat source-side unit 30. Then, the indoor-side control board 81 and the outdoor-side control board 82 have a microcomputer or the like, and transmit or receive control signals or the like with a thermostat 70. The control signals are not transmitted or received between the indoor-side control board 81 and the outdoor-side control board 82. A control device including the indoor-side control board 81 and the outdoor-side control board 82 is called a controller 80.
(6) Basic Operation of Air Conditioning System 1
An air conditioning operation of the air conditioning system 1 includes a fan operation, a cooling operation, and a heating operation. Here, a basic operation of the heating operation will be described with reference to
(6-1) Heat Pump Heating Operation
During the heat pump heating operation, the refrigerant in the refrigerant circuit 61 is suctioned into the compressor 31, and compressed to become a high-pressure gas refrigerant. This high-pressure gas refrigerant is sent from the heat source-side unit 30 to the utilization-side unit 50 via the gas refrigerant connection pipe 37.
The high-pressure gas refrigerant sent to the utilization-side unit 50 is sent to the indoor heat exchanger 40. The high-pressure gas refrigerant sent to the indoor heat exchanger 40 is cooled by heat exchange in the indoor heat exchanger 40 with indoor air F1 (F2) supplied by the indoor fan 24, to be condensed to become a high-pressure liquid refrigerant.
This high-pressure refrigerant is sent from the utilization-side unit 50 to the heat source-side unit 30 via the indoor expansion valve 42 and the liquid refrigerant connection pipe 36. Whereas, indoor air F3 heated in the indoor heat exchanger 40 is sent from the utilization-side unit 50 to the rooms 201 to 204 through the duct 19, for heating.
The high-pressure liquid refrigerant sent to the heat source-side unit 30 is sent to the outdoor expansion valve 34, and decompressed by the outdoor expansion valve 34 to become a low-pressure refrigerant in a gas-liquid two-phase state. This low-pressure refrigerant in the gas-liquid two-phase state is sent to the outdoor heat exchanger 33.
The low-pressure refrigerant in the gas-liquid two-phase state sent to the outdoor heat exchanger 33 is heated by heat exchange in the outdoor heat exchanger 33 with outdoor air supplied by the outdoor fan 35, to evaporate to become a low-pressure gas refrigerant. This low-pressure gas refrigerant is suctioned into the compressor 31 again.
Then, in the heat pump heating operation described above, an outdoor-side microcomputer 82a of the controller 80 controls the indoor temperature Tr in the rooms 201 to 204 to reach a set temperature (hereinafter referred to as an indoor set temperature Ts), by controlling an operating capacity Gr of the compressor 31 and by controlling of an opening degree of the outdoor expansion valve 34 (hereinafter referred to as an opening degree V).
(6-2) Separate Heat Source Heating Operation
During the separate heat source heating operation, the fuel gas valve 12 is opened to supply fuel gas to the combustion unit 10. The fuel gas is mixed with air taken in from the air supply pipe 16 by the furnace fan 13 in the combustion unit 10. The mixed gas of the fuel gas and the air is ignited and burned to generate high-temperature combustion gas.
The high-temperature combustion gas generated in the combustion unit 10 is sent to the furnace heat exchanger 15 as a separate heat source radiator. The high-temperature combustion gas sent to the furnace heat exchanger 15 is cooled by heat exchange in the furnace heat exchanger 15 with the indoor air F1 supplied by the indoor fan 24, to become low-temperature combustion gas. This low-temperature combustion gas is discharged from the gas furnace unit 20 via the exhaust pipe 17. Whereas, the indoor air F2 (F3) heated in the furnace heat exchanger 15 is sent from the utilization-side unit 50 to the rooms 201 to 204 through the duct 19, for heating.
Then, in the separate heat source heating operation described above, an indoor-side microcomputer 81a of the controller 80 controls the indoor temperature Tr in the rooms 201 to 204 to reach the indoor set temperature Ts, by controlling opening and closing of the fuel gas valve 12.
The indoor-side microcomputer 81a of the controller 80 performs control to open the fuel gas valve 12 when a temperature difference obtained by subtracting the indoor set temperature Ts from the indoor temperature Tr becomes large, and the indoor-side microcomputer 81a performs control to close the fuel gas valve 12 when the temperature difference becomes small.
(6-3) Switching Operation Between Heat Pump Heating Operation and Separate Heat Source Heating Operation
In the air conditioning system 1, when the outside air temperature Ta is significantly low, the heat pump heating operation may not be able to cover an air conditioning load (a heating load) in a room (here, the rooms 201 to 204). Therefore, the heat pump heating operation is switched to the separate heat source heating operation in accordance with a decrease in the outside air temperature Ta. On the contrary, the separate heat source heating operation is switched to the heat pump heating operation in accordance with an increase of the outside air temperature Ta.
When an operation of the air conditioning system 1 starts, first, the heat pump heating operation is performed. Then, when the outside air temperature Ta during the heat pump heating operation reaches a first temperature Ta1 or less, and a heating capacity of the heat pump unit 60 reaches an upper limit, the heat pump heating operation is switched to the separate heat source heating operation.
Note that, whether an operating capacity of equipment included in the heat pump unit 60 has reached the upper limit is determined by whether a number N of revolutions of the compressor motor 31a has reached an upper limit number Nu of revolutions, and/or whether the opening degree V of the outdoor expansion valve 34 has reached an upper limit opening degree Vu.
Whereas, in the separate heat source heating operation, the separate heat source heating operation is switched to the heat pump heating operation when the outside air temperature Ta during the separate heat source heating operation reaches a second temperature Ta2 or higher.
(7) Characteristics
In the above embodiment, as illustrated in
This is because the surface provided with the air inlet 11a is the third surface 113 among the plurality of surfaces adjacent to the first surface 111, rather than the second portion 111b of the first surface 111 which is the surface closest to the liquid pipe connection portion 38 and the gas pipe connection portion 39 in the first casing 11 housing the combustion unit 10.
(8) Modifications
The position or shape of the air inlet 11a may be changed to further reduce the risk that the combustion unit 10 serves as an ignition source of the flammable refrigerant R32.
(8-1) First Modification
As illustrated in
Since a concentration of the refrigerant gas decreases as a distance from a leakage point increases, by providing the air inlet 11a of the first casing 11 at a position closer to the end farther from the second casing 41 than the end closer to the second casing 41, the risk that the combustion unit 10 serves as an ignition source of the flammable refrigerant R32 is further reduced.
(8-2) Second Modification
As illustrated in
If the refrigerant leaks from the liquid pipe connection portion 38 and the gas pipe connection portion 39, the refrigerant flows down along the surface 411 and then flows downward along a surface of the first casing 11. Therefore, when the refrigerant is sucked from the air inlet 11a toward the combustion unit 10 by the indoor fan 24, it is considered that a risk that the refrigerant is sucked into a longitudinal slit parallel to a direction of a refrigerant flow is lower than into a lateral slit orthogonal to the refrigerant flow.
(8-3) Third Modification
If the refrigerant leaks from the liquid pipe connection portion 38 and the gas pipe connection portion 39, the refrigerant may flow down along the surface 411 and then flow down along the third surface 113 of the first casing 11 parallel to the surface 411. The air inlet 11a, which is provided not on the third surface 113 parallel to the surface 411 provided with the liquid pipe connection portion 38 and the gas pipe connection portion 39 but on the fourth surface 114 and the fifth surface 115 orthogonal to the surface 411, further reduces the risk of the refrigerant being sucked.
(8-4) Fourth Modification
Thus, since devices and components used are basically the same, the same names and the same reference signs as those in the embodiment are given to devices and components, and detailed description thereof will be omitted.
In the horizontal type, when the surface 411 on which the liquid pipe connection portion 38 and the gas pipe connection portion 39 are disposed is viewed as a front surface, the first casing 11 has the second surface 112 facing the first surface 111, the third surface 113 located between the first surface 111 and the second surface 112 and defined as a front surface, and the fourth surface 114 and the fifth surface 115 adjacent to both the first surface 111 and the third surface 113.
As illustrated in
Each opening of the air inlet 11a has a slit shape, and a longitudinal direction of each opening extends from the first casing 11 toward the second casing 41.
In the horizontal type, if the refrigerant leaks from the liquid pipe connection portion 38 and the gas pipe connection portion 39, it is considered that the refrigerant is retained near a floor surface and the concentration of the refrigerant becomes high near the floor surface, since the refrigerant has a larger specific gravity than air.
The air inlet 11a, which is provided on the fourth surface 114 and is thus located on the surface farthest from the floor surface among the surfaces constituting the first casing 11, further reduces the risk of the refrigerant being sucked.
In the fourth modification, as can be seen from
(8-5) Fifth Modification
In the horizontal type of the fourth modification, if the refrigerant leaks from the liquid pipe connection portion 38 and the gas pipe connection portion 39, it is considered that the concentration of the refrigerant becomes high near the floor surface since the refrigerant has a larger specific gravity than air, and thus the air inlet 11a is provided on the fourth surface 114 farthest from the floor surface.
However, as can be seen from
Accordingly, as illustrated in
As illustrated in
However, since the air inlet 11a is arranged in a row from the third surface 113 to the fourth surface 114 in the fifth modification, the air inlet 11a is separated from the second portion 111b of the first surface 111 as compared with in the fourth modification, and the risk of the refrigerant being sucked is further suppressed.
(9) Other Embodiments
In the embodiment and the modifications, the air conditioning system combining a heat pump capable of heating and cooling and a furnace is taken as an example, but the present disclosure is not limited thereto.
For example, the air conditioning system may be an air conditioning system combining an air conditioner dedicated to cooling and a furnace.
Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-032295 | Feb 2020 | JP | national |
This application is a Continuation of PCT International Application No. PCT/JP2021/007353, filed on Feb. 26, 2021, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 2020-032295, filed in Japan on Feb. 27, 2020, all of which are hereby expressly incorporated by reference into the present application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2021/007353 | Feb 2021 | US |
| Child | 17894245 | US |
