Patent Application
20240219064
The present disclosure relates to an air-conditioning apparatus that conditions air in a plurality of spaces, and to a method for installing an air-conditioning apparatus.
A direct-expansion air-conditioning apparatus including an outdoor unit that is a heat source unit and installed outdoors and an indoor unit installed indoors has been conventionally known (for example, Patent Literature 1). In the direct-expansion air-conditioning apparatus, refrigerant is circulated between the outdoor unit and the indoor unit and heat generated in the outdoor unit is transferred to the indoor unit thereby cooling or heating an air-conditioned space such as a room. The direct-expansion air-conditioning apparatus often uses a hydrofluorocarbon (HFC)-series refrigerant.
Another air-conditioning apparatus including an outdoor unit, an indoor unit, and a relay unit connected between the outdoor unit and the indoor unit has been known. In the relay unit, a heat medium such as water exchanges heat with refrigerant supplied from the outdoor unit and circulates in the indoor unit thereby cooling or heating an air-conditioned space (for example, Patent Literature 2).
In the conventional direct-expansion air-conditioning apparatus, a flammable or toxic refrigerant circulates in the indoor unit installed in a room. Thus, for the purpose of ensuring safety for leakage of the refrigerant in the room, ventilation of the room as well as installation of a refrigerant leakage sensor, a refrigerant shut-off valve, and the like are required. This results in an increase in cost of the apparatus and an increase in power consumption of the apparatus.
The air-conditioning apparatus including the relay unit ensures safety by circulating a harmless heat medium such as water in the indoor unit installed in a room. However, as in a case of a variable refrigerant flow (VRF) system where many indoor units are connected to the relay unit, the size of the relay unit is increased. In addition, power of the pump required to convey a heat medium such as water is increased, which results in an increase in power consumption of the apparatus.
The present disclosure has been made to solve the above problems, and it is an object of the present disclosure to provide an air-conditioning apparatus and a method for installing an air-conditioning apparatus that can achieve both ensuring safety and reducing power consumption.
An air-conditioning apparatus according to one embodiment of the present disclosure includes: an outdoor unit including a compressor configured to cause refrigerant to circulate in a refrigerant circuit, and an outdoor heat exchanger through which the refrigerant flows; a first indoor unit including a first indoor heat exchanger through which the refrigerant flows; a relay unit including a relay heat exchanger through which the refrigerant exchanges heat with a heat medium different from the refrigerant, and a pump configured to cause the heat medium to circulate in a heat medium circuit; and a second indoor unit including a second indoor heat exchanger through which the heat medium flows, wherein the first indoor unit is installed in a first air-conditioned space, the second indoor unit is installed in a second air-conditioned space, the first air-conditioned space has a volume such that a concentration of the refrigerant in the first air-conditioned space is lower than a reference value even when a total amount of the refrigerant filled in the refrigerant circuit leaks in the first air-conditioned space, and a volume of the second air-conditioned space is smaller than the volume of the first air-conditioned space.
A method for installing an air-conditioning apparatus according to another embodiment of the present disclosure is a method for installing an air-conditioning apparatus, the air-conditioning apparatus including an outdoor unit including a compressor configured to cause refrigerant to circulate in a refrigerant circuit, and an outdoor heat exchanger through which the refrigerant flows, a first indoor unit including a first indoor heat exchanger through which the refrigerant flows, a relay unit including a relay heat exchanger through which the refrigerant exchanges heat with a heat medium different from the refrigerant, and a pump configured to cause the heat medium to circulate in a heat medium circuit, and a second indoor unit including a second indoor heat exchanger through which the heat medium flows, the method including: determining, for a volume of an air-conditioned space, whether or not a concentration of the refrigerant in the air-conditioned space is lower than a reference value when a total amount of the refrigerant filled in the refrigerant circuit leaks in the air-conditioned space; and installing the first indoor unit in the air-conditioned space when the concentration of the refrigerant is lower than the reference value, and installing the second indoor unit in the air-conditioned space when the concentration of the refrigerant is equal to or higher than the reference value.
In the air-conditioning apparatus and the method for installing an air-conditioning apparatus of one embodiment of the present disclosure, the first indoor unit through which the refrigerant flows is installed in the first air-conditioned space that is defined as a large space, while the second indoor unit through which the heat medium flows is installed in the second air-conditioned space that is smaller in volume than the first air-conditioned space, so that ensuring safety for leakage of the refrigerant and reducing the power consumption can both be achieved.
Hereinafter, embodiments will be described with reference to the drawings. Note that in the drawings below, the same reference signs denote the same or equivalent components, which are common throughout the entire specification. Further, the components described throughout the entire specification are merely examples, and do not intend to limit the components to those described in the specification. Further, the relationship of sizes of the components in the drawings described below may differ from that of actual ones.
The outdoor unit 1 and the first indoor units 2a to 2c are connected by refrigerant pipes 5a and 5b through which refrigerant flows. The outdoor unit 1 and the relay unit 4 are also connected by the refrigerant pipes 5a and 5b. The first indoor units 2a to 2c, and the relay unit 4 are connected in parallel to the outdoor unit 1. The relay unit 4 and the second indoor units 3a to 3c are connected by heat medium pipes 6a and 6b through which a heat medium flows. The second indoor units 3a to 3c are connected in parallel to the relay unit 4. Heat generated in the outdoor unit 1 is transferred by refrigerant flowing through the refrigerant pipes 5a and 5b to the first indoor units 2a to 2c and to the relay unit 4. The heat converted in the relay unit 4 is transferred by a heat medium flowing through the heat medium pipes 6a and 6b to the second indoor units 3a to 3c.
The first indoor units 2a to 2c in the air-conditioning apparatus 100 are configured to directly cool or heat an air-conditioned space with the refrigerant supplied from the outdoor unit 1. The second indoor units 3a to 3c are configured to cool or heat an air-conditioned space with a heat medium which received heat from the refrigerant supplied from the outdoor unit 1. That is, the air-conditioning apparatus 100 includes both a first indoor unit configured to directly use refrigerant supplied from the outdoor unit 1, and a second indoor unit configured to indirectly use the refrigerant.
Examples of the refrigerant to be used in the air-conditioning apparatus 100 include a single refrigerant such as R32, a near-azeotropic refrigerant mixture such as R410A, a relatively-low global warming potential refrigerant containing a double bond or CF3I in its chemical formula, a mixture containing the relatively-low global warming potential refrigerant, and a natural refrigerant such as CF3I, CO2, or propane.
Examples of the heat medium to be used in the air-conditioning apparatus 100 include water, brine (antifreeze), a liquid mixture of brine and water, and a liquid mixture of water and a highly anticorrosive additive. Note that the term “heat medium” in the present disclosure refers to a heat medium other than the refrigerant and not having toxicity or flammability.
The outdoor unit 1 includes a compressor 11, a flow switching valve 12, an outdoor heat exchanger 13, an outdoor fan 14, an accumulator 15, and an outdoor controller 16. The compressor 11 is configured to suction low-temperature low-pressure gas refrigerant, compress the suctioned gas refrigerant into a high-temperature high-pressure state, and discharge the compressed high-temperature high-pressure gas refrigerant. The compressor 11 causes the refrigerant to circulate through the refrigerant circuit A. The compressor 11 is, for example, an inverter-type compressor whose capacity is controllable.
The flow switching valve 12 is, for example, a four-way valve. The flow switching valve 12 switches between flow passages for refrigerant discharged from the compressor 11 depending on the mode of operation of the first indoor units 2a to 2c and the second indoor units 3a to 3c. The flow switching valve 12 is switched to a flow passage illustrated by the solid lines in
The outdoor heat exchanger 13 is, for example, a fin-and-tube heat exchanger. Through the outdoor heat exchanger 13, refrigerant exchanges heat with air supplied by the outdoor fan 14. The outdoor heat exchanger 13 serves as a condenser during cooling operation to condense and liquefy the refrigerant. The outdoor heat exchanger 13 serves as an evaporator during heating operation to evaporate and gasify the refrigerant.
The outdoor fan 14 is, for example, a propeller fan. The outdoor fan 14 supplies air around the outdoor unit 1 to the outdoor heat exchanger 13. The outdoor controller 16 controls a rotation speed of the outdoor fan 14 to control the condensation capacity or the evaporation capacity of the outdoor heat exchanger 13. The accumulator 15 is provided on a suction side of the compressor 11, and has a function of separating the refrigerant into liquid refrigerant and gas refrigerant and a function of accumulating surplus refrigerant.
The outdoor controller 16 controls operation of the compressor 11, the flow switching valve 12, and the outdoor fan 14. The outdoor controller 16 is constituted by a processing device including a memory configured to store data and programs necessary for controlling the operation, and a CPU configured to execute the programs, or is constituted by dedicated hardware such as ASIC or FPGA or by both the processing device and the dedicated hardware. The outdoor controller 16 controls an operating frequency of the compressor 11, the flow passages in the flow switching valve 12, and the rotation speed of the outdoor fan 14 based on a detection result of a pressure sensor (not illustrated) installed in the outdoor unit 1 to detect a refrigerant pressure, and a detection result of a temperature sensor (not illustrated) installed in the outdoor unit 1 to detect a refrigerant temperature or an outside air temperature. The outdoor controller 16 can perform data communication with first controllers 24 installed in the first indoor units 2a to 2c, second controllers 34 installed in the second indoor units 3a to 3c, and a controller 44 installed in the relay unit 4.
Each of the first indoor units 2a to 2c supplies heat generated by the outdoor unit 1 to a cooling load or a heating load in the air-conditioned space. Each of the first indoor units 2a to 2c includes a first indoor heat exchanger 21, an expansion device 22, a first indoor fan 23, and the first controller 24. The first indoor heat exchanger 21 is, for example, a fin-and-tube heat exchanger. Through the first indoor heat exchanger 21, refrigerant exchanges heat with air supplied by the first indoor fan 23. The first indoor heat exchanger 21 serves as a condenser during heating operation to condense and liquefy the refrigerant. The first indoor heat exchanger 21 serves as an evaporator during cooling operation to evaporate and gasify the refrigerant.
The expansion device 22 is an electronic expansion valve whose opening degree is variably controlled. The expansion device 22 is connected in series to the first indoor heat exchanger 21 and reduces a pressure of refrigerant flowing out from the first indoor heat exchanger 21 or refrigerant flowing into the first indoor heat exchanger 21 to expand the refrigerant.
The first indoor fan 23 is, for example, a cross flow fan. The first indoor fan 23 supplies air in the air-conditioned space to the first indoor heat exchanger 21. The first controller 24 controls a rotation speed of the first indoor fan 23 to control the condensation capacity or the evaporation capacity of the first indoor heat exchanger 21.
The first controller 24 controls operation of the expansion device 22 and the first indoor fan 23. The first controller 24 is constituted by a processing device including a memory configured to store data and programs necessary for controlling the operation, and a CPU configured to execute the programs, or is constituted by dedicated hardware such as ASIC or FPGA or by both the processing device and the dedicated hardware. The first controller 24 controls an opening degree of the expansion device 22 and the rotation speed of the first indoor fan 23 based on a detection result of a temperature sensor (not illustrated) configured to detect a temperature in the air-conditioned space, and a detection result of a temperature sensor (not illustrated) configured to detect a refrigerant temperature at an outlet and an inlet of each of the first indoor units 2a to 2c. The temperature sensor is, for example, a thermistor. The first controller 24 controls the opening degree of the expansion device 22 and the rotation speed of the first indoor fan 23 in response to, for example, a difference between the temperature in the air-conditioned space and its target temperature.
Each of the second indoor units 3a to 3c supplies heat converted by the relay unit 4 to a cooling load or a heating load in the air-conditioned space. Each of the second indoor units 3a to 3c includes a second indoor heat exchanger 31, a flow control valve 32, a second indoor fan 33, and the second controller 34. The second indoor heat exchanger 31 is, for example, a fin-and-tube heat exchanger. Through the second indoor heat exchanger 31, a heat medium exchanges heat with air supplied by the second indoor fan 33.
The flow control valve 32 is a solenoid valve whose opening degree is variably controlled. The flow control valve 32 is connected in series to the second indoor heat exchanger 31, and controls the flow rate of a heat medium flowing through the second indoor heat exchanger 31.
The second indoor fan 33 is, for example, a cross flow fan. The second indoor fan 33 supplies air in the air-conditioned space to the second indoor heat exchanger 31. The second controller 34 controls a rotation speed of the second indoor fan 33 to control the heating capacity or the cooling capacity of the second indoor heat exchanger 31.
The second controller 34 controls operation of the flow control valve 32 and the second indoor fan 33. The second controller 34 is constituted by a processing device including a memory configured to store data and programs necessary for controlling the operation, and a CPU configured to execute the programs, or is constituted by dedicated hardware such as ASIC or FPGA or by both the processing device and the dedicated hardware. The second controller 34 controls an opening degree of the flow control valve 32 and the rotation speed of the second indoor fan 33 based on a detection result of a temperature sensor (not illustrated) configured to detect a temperature in the air-conditioned space, and a detection result of a temperature sensor (not illustrated) configured to detect a heat medium temperature at an outlet and an inlet of each of the second indoor units 3a to 3c. The temperature sensor is, for example, a thermistor. The second controller 34 controls the opening degree of the flow control valve 32 and the rotation speed of the second indoor fan 33 in response to, for example, a difference between the temperature in the air-conditioned space and its target temperature. Alternatively, the second controller 34 may calculate a flow rate of the heat medium from a detection result of a pressure sensor (not illustrated) attached upstream or downstream of the flow control valve 32, and from a Cv value stored in advance corresponding to the opening degree of the flow control valve 32, and control the opening degree of the flow control valve 32 based on the calculation result.
The relay unit 4 includes a relay heat exchanger 41, an expansion device 42, a pump 43, and the controller 44. The relay heat exchanger 41 is, for example, a plate heat exchanger. Through the relay heat exchanger 41, refrigerant supplied from the outdoor unit 1 exchanges heat with the heat medium that is circulated by the pump 43. This allows heat stored in the refrigerant supplied from the outdoor unit 1 to be transferred to the heat medium. The relay heat exchanger 41 serves as a condenser during heating operation to condense and liquefy the refrigerant. The relay heat exchanger 41 serves as an evaporator during cooling operation to evaporate and gasify the refrigerant.
The expansion device 42 is an electronic expansion valve whose opening degree is variably controlled. The expansion device 42 is connected in series to the relay heat exchanger 41 and reduces a pressure of refrigerant flowing out from the relay heat exchanger 41 or refrigerant flowing into the relay heat exchanger 41 to expand the refrigerant.
The pump 43 is, for example, an inverter-type centrifugal pump whose capacity is controllable. The pump 43 includes a motor that is driven by an inverter. The pump 43 is driven by the motor used as a power source, and applies a pressure to the heat medium to cause the heat medium to circulate in the heat medium circuit B. Note that in
The controller 44 controls operation of the expansion device 42 and the pump 43. The controller 44 is constituted by a processing device including a memory configured to store data and programs necessary for controlling the operation, and a CPU configured to execute the programs, or is constituted by dedicated hardware such as ASIC or FPGA or by both the processing device and the dedicated hardware. The controller 44 controls the opening degree of the expansion device 42 based on a detection result of temperature sensors (not illustrated) configured to detect a refrigerant temperature at a refrigerant-side outlet and a refrigerant-side inlet of the relay heat exchanger 41. Alternatively, the controller 44 may control the opening degree of the expansion device 42 in response to an operating capacity of the second indoor units 3a to 3c. The controller 44 may perform data communication with the first controllers 24 to control the expansion device 42 in conjunction with the expansion devices 22 installed in the first indoor units 2a to 2c. The controller 44 controls an operating frequency of the pump 43 based on a detection result of pressure sensors (not illustrated) attached at an outlet and inlet of the pump 43 to detect a pressure of the heat medium, and based on a graph in which the capability value of the pump 43 or other data is associated with the operating frequency. Alternatively, the controller 44 may control the operating frequency of the pump 43 in response to the operating capacity of the second indoor units 3a to 3c.
The air-conditioning apparatus 100 in the present embodiment performs cooling operation or heating operation based on an instruction transmitted from remote controls (not illustrated) or other components to the first indoor units 2a to 2c and the second indoor units 3a to 3c. The cooling operation and the heating operation are implemented by switching the flow switching valve 12 in the outdoor unit 1 between the flow passage for the cooling operation and the flow passage for the heating operation. The solid arrows in
In the heating operation, high-temperature high-pressure gas refrigerant discharged from the compressor 11 passes through the flow switching valve 12 and flows out from the outdoor unit 1, and then passes through the refrigerant pipe 5a to be divided into the first indoor units 2a to 2c and the relay unit 4. The refrigerant flowing into the first indoor units 2a to 2c exchanges heat with air supplied by the first indoor fans 23 through the first indoor heat exchangers 21, and thus condenses and liquefies. At this time, the refrigerant transfers heat to the air in the air-conditioned space, so that the air-conditioned spaces where the first indoor units 2a to 2c are installed are heated. The refrigerant flowing out from the first indoor heat exchangers 21 is reduced in pressure by the expansion devices 22 and then flows out from the first indoor units 2a to 2c. Then, the refrigerant passes through the refrigerant pipe 5b and flows into the outdoor unit 1.
The refrigerant flowing into the relay unit 4 exchanges heat with a heat medium that is circulated by the pump 43 through the relay heat exchanger 41, and thus condenses and liquefies. At this time, the refrigerant transfers heat to the heat medium, so that the heat medium is heated. The refrigerant flowing out from the relay heat exchanger 41 is reduced in pressure by the expansion device 42 and flows out from the relay unit 4. Then, this refrigerant merges with the refrigerant flowing out from the first indoor units 2a to 2c at the junction of the refrigerant pipe 5b and flows into the outdoor unit 1.
The refrigerant flowing into the outdoor unit 1 flows into the outdoor heat exchanger 13. The refrigerant flowing into the outdoor heat exchanger 13 exchanges heat with air supplied by the outdoor fan 14, and thus evaporates and gasifies. The refrigerant flowing out from the outdoor heat exchanger 13 is suctioned again into the compressor 11 via the flow switching valve 12 and the accumulator 15.
The heat medium heated through the relay heat exchanger 41 passes through the heat medium pipe 6a and flows into each of the second indoor units 3a to 3c. The heat medium flowing into each of the second indoor units 3a to 3c exchanges heat with air supplied by the second indoor fan 33 through the second indoor heat exchanger 31. At this time, the heat medium transfers heat to the air in the air-conditioned space, so that the air-conditioned spaces where the second indoor units 3a to 3c are installed are heated. The heat medium flowing out from the second indoor heat exchangers 31 passes through the flow control valves 32 and flows out from the second indoor units 3a to 3c. Then, the heat medium passes through the heat medium pipe 6b and flows into the relay unit 4.
In the cooling operation, high-temperature high-pressure gas refrigerant discharged from the compressor 11 passes through the flow switching valve 12 and flows into the outdoor heat exchanger 13. The refrigerant flowing into the outdoor heat exchanger 13 exchanges heat with air supplied by the outdoor fan 14, and thus condenses and liquefies. The refrigerant flowing out from the outdoor heat exchanger 13 passes through the refrigerant pipe 5b and is divided into the first indoor units 2a to 2c and the relay unit 4.
The refrigerant flowing into each of the first indoor units 2a to 2c is reduced in pressure by the expansion device 22 and brought into a low-temperature two-phase gas-liquid state, and then flows into the first indoor heat exchanger 21. The refrigerant flowing into the first indoor heat exchanger 21 exchanges heat with air supplied by the first indoor fan 23, and thus evaporates and gasifies. At this time, the refrigerant removes heat from the air in the air-conditioned space, so that the air-conditioned spaces where the first indoor units 2a to 2c are installed are cooled. The refrigerant flowing out from the first indoor heat exchanger 21 passes through the refrigerant pipe 5a and flows into the outdoor unit 1.
The refrigerant flowing into the relay unit 4 exchanges heat with a heat medium that is circulated by the pump 43 through the relay heat exchanger 41, and thus evaporates and gasifies. At this time, the refrigerant removes heat from the heat medium, so that the heat medium is cooled. The refrigerant flowing out from the relay heat exchanger 41 merges with the refrigerant flowing out from the first indoor units 2a to 2c at the junction of the refrigerant pipe 5a, and then flows into the outdoor unit 1. The refrigerant flowing into the outdoor unit 1 is suctioned again into the compressor 11 via the flow switching valve 12 and the accumulator 15.
The heat medium cooled through the relay heat exchanger 41 passes through the heat medium pipe 6a and flows into each of the second indoor units 3a to 3c. The heat medium flowing into each of the second indoor units 3a to 3c exchanges heat with air supplied by the second indoor fan 33 through the second indoor heat exchanger 31. At this time, the heat medium removes heat from the air in the air-conditioned space, so that the air-conditioned spaces where the second indoor units 3a to 3c are installed are cooled. The heat medium flowing out from the second indoor heat exchangers 31 passes through the flow control valves 32 and flows out from the second indoor units 3a to 3c. Then, the heat medium passes through the heat medium pipe 6b and flows into the relay unit 4.
Next, with reference back to
In the present Embodiment, a volume of the first air-conditioned space 301 is larger than a volume of the second air-conditioned space 302, while the volume of the second air-conditioned space 302 is larger than a volume of the second air-conditioned space 303. The first air-conditioned space 301 is a large space, while the second air-conditioned spaces 302 and 303 are small spaces. In the present disclosure, a space having a volume such that, even when a total amount of the refrigerant (total refrigerant amount) filled in the refrigerant circuit A in the air-conditioning apparatus 100 leaks, the refrigerant concentration in the space is still lower than a reference value, is defined as a “large space.” In addition, a space having a volume such that, when the total refrigerant amount filled in the refrigerant circuit A in the air-conditioning apparatus 100 leaks, the average refrigerant concentration in the space is equal to or higher than the reference value, is defined as a “small space.”
A refrigerant concentration D [kg/m3] when the whole amount of refrigerant leaks in a single space is calculated using Expression (1) below based on a total refrigerant amount M [kg] filled in the refrigerant circuit A in the air-conditioning apparatus 100 and a volume Q [m3] of each air-conditioned space.
A space where the refrigerant concentration D is lower than the reference value is defined as a large space, while a space where the refrigerant concentration D is equal to or higher than the reference value is defined as a small space. The reference value is an allowable refrigerant concentration, which is the maximum refrigerant concentration in the air that is specified to reduce a risk at the time of refrigerant leakage. The risk at the time of refrigerant leakage refers to a risk due to toxicity or flammability of the refrigerant or a risk of oxygen deficiency. The reference value is, for example, one-fourth of a lower flammability limit (LFL) to the refrigerant used in the air-conditioning apparatus 100. Note that the reference value is not limited to one-fourth of LFL, and it suffices that the reference value is equal to or lower than LFL. For example, when the air-conditioning apparatus 100 uses a slightly flammable refrigerant such as R32, the reference value is set at, or around, 0.66 [kg/m3].
As illustrated in
The first indoor units 2a to 2c are installed in the first air-conditioned space 301 that is defined as a large space. According to this installation, if the refrigerant leaks from the first indoor units 2a to 2c, the refrigerant concentration in the first air-conditioned space 301 does not exceed the reference value. This can reduce the risk due to toxicity or flammability of the refrigerant or the risk of oxygen deficiency. Therefore, the first indoor units 2a to 2c installed in the large space can omit air ventilation and safety measures such as a refrigerant leakage sensor and a refrigerant shut-off valve.
The second indoor unit 3a is installed in the second air-conditioned space 303 that is defined as a small space. The second indoor units 3b and 3c are installed in the second air-conditioned space 302 that is also defined as a small space. Since the heat medium flows in the second indoor units 3a to 3c, there is no risk due to toxicity or flammability of the refrigerant or no risk of oxygen deficiency if the heat medium leaks from the second indoor units 3a to 3c. Even if the refrigerant leaks from the air-conditioning apparatus 100, but still it leaks in a space separate from the second air-conditioned spaces 302 and 303. Thus, the refrigerant does not leak to the second air-conditioned spaces 302 and 303.
It is preferable that the relay unit 4 be installed in such a manner that a distance from the outdoor unit 1 to the relay unit 4 is shorter than a distance from the outdoor unit 1 to the first indoor units 2a to 2c. It is preferable that the relay unit 4 and the second indoor units 3a to 3c be installed in such a manner that a distance from the relay unit 4 to the second indoor units 3a to 3c is shorter than the distance from the outdoor unit 1 to the first indoor units 2a to 2c. This can reduce power required to convey a heat medium in the heat medium circuit B, and reduce the power consumption accordingly.
As described above, in the air-conditioning apparatus 100 in the present embodiment, the first indoor units in which refrigerant flows are installed in the large space, while the second indoor units in which a heat medium other than the refrigerant flows are installed in the small spaces. Consequently, even when using refrigerant having flammability or toxicity, the air-conditioning apparatus 100 can still ensure safety. The first indoor units can omit a refrigerant leakage sensor, a refrigerant shut-off valve, and other safety measures. Since the second indoor units are installed in only the small spaces, the number of second indoor units can be reduced and the power required for the pump 43 in the relay unit 4 can be minimized. Therefore, a reduction in the power consumption can be achieved. That is, the air-conditioning apparatus 100 in the present embodiment selects installation of either the first indoor unit in which refrigerant flows, or the second indoor unit in which a heat medium flows, depending on the volume of the air-conditioned space, and can thereby achieve both ensuring safety and reducing the power consumption.
Embodiment 2 is described below. In Embodiment 1 described above, the air-conditioning apparatus 100 has been described as including one relay unit 4. However, Embodiment 2 is different from Embodiment 1 in that the air-conditioning apparatus includes a plurality of relay units 4.
The outdoor unit 1 and the first indoor units 2a to 2c are connected by the refrigerant pipes 5a and 5b through which refrigerant flows. The outdoor unit 1 and the relay units 4a and 4b are also connected by the refrigerant pipes 5a and 5b. The first indoor units 2a to 2c, and the relay units 4a and 4b are connected in parallel to the outdoor unit 1. The relay unit 4a and the second indoor unit 3a are connected by the heat medium pipes 6a and 6b through which a heat medium flows. The relay unit 4b and the second indoor units 3b and 3c are connected by the heat medium pipes 6a and 6b through which a heat medium flows. The second indoor units 3b and 3c are connected in parallel to the relay unit 4b. Heat generated in the outdoor unit 1 is supplied by refrigerant flowing through the refrigerant pipes 5a and 5b to the first indoor units 2a to 2c and to the relay units 4a and 4b. The heat converted in the relay units 4a and 4b is supplied by a heat medium flowing through the heat medium pipes 6a and 6b to the second indoor units 3a to 3c.
As illustrated in
The non-air-conditioned space 203 is adjacent to the second air-conditioned spaces 302 and 303 where the second indoor units 3a to 3c are installed. This can reduce the length of the heat medium pipes 6a and 6b connecting the relay units 4a and 4b to the second indoor units 3a to 3c. As the length of the heat medium pipes 6a and 6b is reduced, a pressure loss generated in the pipes is decreased, so that the power required for the pumps 43 in the relay units 4a and 4b to convey a heat medium can be reduced. This can downsize the pumps 43 in the relay units 4a and 4b, and downsize housings of the relay units 4a and 4b accordingly. It is also possible to decrease the total amount of heat medium to be filled in the heat medium circuit B. Accordingly, a thermal capacity of the heat medium can be decreased, which leads to a reduction in start-up time required for the second indoor units 3a to 3c to start blowing heated or cooled air.
The relay units 4a and 4b in the air-conditioning apparatus 100A in the present embodiment operate individually in response to the operating conditions of the second indoor units 3a to 3c connected to the relay units 4a and 4b. For example, in a case where the second indoor unit 3a is in operation, while the second indoor units 3b and 3c are deactivated, the controller 44 activates the expansion device 42 and the pump 43 in the relay unit 4a connected to the second indoor unit 3a, while deactivating the expansion device 42 and the pump 43 in the relay unit 4b connected to the second indoor units 3b and 3c. Alternatively, in a case where the second indoor unit 3a is deactivated, while the second indoor units 3b and 3c are in operation, the controller 44 deactivates the expansion device 42 and the pump 43 in the relay unit 4a, while activating the expansion device 42 and the pump 43 in the relay unit 4b.
The second indoor units 3b and 3c connected to the relay unit 4b are installed in the same second air-conditioned space 302. It is thus also possible to reduce the frequency at which the relay unit 4b is activated/deactivated by operating the second indoor units 3b and 3c in conjunction with each other.
As described above, the air-conditioning apparatus 100A in the present embodiment can obtain the same effects as those achieved by Embodiment 1. By including a plurality of relay units, the air-conditioning apparatus 100A can downsize the relay units and reduce the power consumption as described above, and can also improve the comfort provided by the second indoor units 3a to 3c.
Embodiment 3 is described below. Embodiment 3 is different from Embodiment 2 in configuration of the second indoor units 3a to 3c in an air-conditioning apparatus 100B. The schematic configuration of the air-conditioning apparatus 100B in the present embodiment is the same as that of the air-conditioning apparatus 100A in Embodiment 2 illustrated in
Specifically, the second controllers 34 in the second indoor units 3a to 3c transmit, to the controllers 44 in the relay units 4a and 4b, a detection result of a temperature sensor (not illustrated) configured to detect a temperature in the air-conditioned space or a heat medium temperature at an outlet and an inlet of each of the second indoor units 3a to 3c. This allows the controllers 44 in the relay units 4a and 4b to control the operating frequency of the pumps 43 based on an air conditioning load in the second air-conditioned spaces 302 and 303.
As described above, the air-conditioning apparatus 100B in the present embodiment can obtain the same effects as those achieved by Embodiment 2, and can simplify a configuration of the second indoor units 3a to 3c by omitting the flow control valves 32 from the second indoor units 3a to 3c. With this configuration, it is possible to downsize the second indoor units 3a to 3c and reduce costs of the second indoor units 3a to 3c.
While embodiments have been described above, the present disclosure is not limited to the above embodiments, and can be variously modified or combined without departing from the scope of the gist of the present disclosure. For example, the ratio between the number of first indoor units and the number of second indoor units is not particularly limited, and may be set appropriate to the air-conditioned spaces in a building. When the ratio of the first indoor units is higher than the ratio of the second indoor units, a necessary amount of heat exchange with a heat medium is decreased, so that a loss of capacity can be reduced. It is also possible to reduce the power required for the pump 43 in the relay unit 4. In contrast, when the ratio of the second indoor units is higher than the ratio of the first indoor units, the amount of refrigerant to be filled in the refrigerant circuit A can be decreased.
The air-conditioning apparatuses in Embodiments 1 to 3 described above have the configuration in which each of the indoor units performs either cooling operation or heating operation. However, the air-conditioning apparatuses in Embodiments 1 to 3 may employ another configuration in which an indoor unit performing the cooling operation and an indoor unit performing the heating operation both exist to enable the cooling operation and the heating operation to be performed simultaneously.
The relay unit 4 may also include a plate heat exchanger through which primary-side refrigerant supplied from the outdoor unit 1 exchanges heat with secondary-side refrigerant, in addition to the relay heat exchanger 41. In this case, in the relay unit 4, the primary-side refrigerant supplied from the outdoor unit 1 exchanges heat with the secondary-side refrigerant, and the secondary-side refrigerant exchanges heat with a heat medium. Further, by providing a compressor in a refrigerant circuit through which the secondary-side refrigerant flows, a hot-water supply function of enabling high-temperature hot water to be supplied can also be provided in addition to the air-conditioning function. In this case, exhaust heat may be collected in the heat medium circuit B and used to perform air-conditioning.
In the above embodiments, the outdoor unit 1, the first indoor units 2a to 2c, the second indoor units 3a to 3c, and the relay unit 4 are provided with their respective controllers, however, the air-conditioning apparatus is not limited to having this configuration. For example, the air-conditioning apparatus may include a controller in a room of a building such as a control room separately from the outdoor unit 1, the first indoor units 2a to 2c, the second indoor units 3a to 3c, and the relay unit 4, such that the controller controls each of these units. Alternatively, any of the outdoor unit 1, the first indoor units 2a to 2c, the second indoor units 3a to 3c, and the relay unit 4 may include a controller, such that the controller controls the other units.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/026925 | 7/19/2021 | WO |
