Technical Field
[0001] The present disclosure relates to an air-conditioning apparatus. The present disclosure
relates more particularly to an air-conditioning apparatus that circulates a heat
medium, such as water, which is different from a refrigerant, to perform air-conditioning.
Background Art
[0002] An air-conditioning apparatus is known that includes a heat-source-side refrigerant,
a refrigerant circulation circuit in which an outdoor unit and a relay unit are connected
by pipes to circulate the heat-source-side refrigerant therein, and a heat medium
circulation circuit in which the relay unit and an indoor unit are connected by pipes
to circulate a heat medium (indoor-side refrigerant) therein (see, for example, Patent
Literature 1). In the heat-source-side refrigerant circulation circuit, the outdoor
unit and the relay unit are connected by pipes, and, in the heat medium circulation
circuit, the relay unit and a plurality of indoor units are connected by pipes. Through
heat exchange between the heat-source-side refrigerant and the heat medium at a heat
medium heat exchanger provided in the relay unit, the heat medium supplies heating
energy or cooling energy to an indoor side, whereby air-conditioning is performed.
Citation List
Patent Literature
[0003] Patent Literature 1: Japanese Unexamined Patent Application Publication No.
2017-101855
Summary of Invention
Technical Problem
[0004] However, in the air-conditioning apparatus of Patent Literature 1, the temperature
of the heat medium supplied to an indoor unit is controlled according to an indoor
set temperature of the indoor unit. In controlling the temperature of the heat medium,
no data on indoor space in which air-conditioning is performed by the indoor unit
is used. Consequently, in the air-conditioning apparatus of Patent Literature 1, even
when a condition of the indoor space is changed, the temperature of the heat medium
supplied to the indoor unit is not changed, and as a result, control suitable to the
condition of the indoor space cannot be performed.
[0005] The present disclosure has been made to solve the above problem, and an object thereof
is to provide an air-conditioning apparatus capable of saving energy by utilizing
data relating to indoor units.
Solution to Problem
[0006] An air-conditioning apparatus of an embodiment of the present disclosure includes
a heat medium circulation circuit and a heat-source-side refrigerant circulation circuit.
In the heat medium circulation circuit, a pump configured to pressurize a heat medium
that contains water or brine and transfers heat, an indoor heat exchanger configured
to cause heat exchange to be performed between an indoor air of an air-conditioned
space and the heat medium, and a flow control device installed in correspondence with
the indoor heat exchanger and configured to control a flow rate of the heat medium
passing through the indoor heat exchanger are connected by a pipe to circulate the
heat medium therein. In the heat-source-side refrigerant circulation circuit, a compressor
configured to compress a heat-source-side refrigerant, a heat-source-side heat exchanger
configured to cause heat exchange to be performed between the heat-source-side refrigerant
and an outdoor air, an expansion device configured to decompress the heat-source-side
refrigerant, and a heat medium heat exchanger configured to exchange heat between
the heat-source-side refrigerant and the heat medium are connected by a pipe. A plurality
of the indoor heat exchangers are installed in respective indoor units. Each of the
indoor units includes a detection device configured to detect a physical quantity
related to a heat quantity involved in heat exchange of the indoor heat exchanger,
and is configured to perform communication by a signal containing data on detection
of the detection device.
Advantageous Effects of Invention
[0007] According to an embodiment of the present disclosure, because each indoor unit is
provided with a detection device that detects a heat quantity involved in heat exchange
of the indoor heat exchanger, data obtained by detection in the indoor unit can be
utilized in operation of the heat-source-side refrigerant circulation circuit. As
a result, energy saving can be achieved.
Brief Description of Drawings
[0008]
[Fig. 1] Fig. 1 is a schematic diagram illustrating an installation example of an
air-conditioning apparatus 0 according to Embodiment 1 of the present disclosure.
[Fig. 2] Fig. 2 is a diagram illustrating an example of a configuration of the air-conditioning
apparatus 0 according to Embodiment 1 of the present disclosure.
[Fig. 3] Fig. 3 is a diagram illustrating a configuration of a relay unit control
device 200 according to Embodiment 1 of the present disclosure.
[Fig. 4] Fig. 4 is a flowchart illustrating a control performed by the relay unit
control device 200 according to Embodiment 1 of the present disclosure.
[Fig. 5] Fig. 5 includes graphs illustrating as a whole an example of an operation
result of the air-conditioning apparatus 0 according to Embodiment 1 of the present
disclosure.
[Fig. 6] Fig. 6 is a diagram illustrating an example of a configuration of an air-conditioning
apparatus 0 according to Embodiment 2 of the present disclosure.
[Fig. 7] Fig. 7 is a diagram illustrating a configuration of an air-conditioning apparatus
0 according to Embodiment 3 of the present disclosure.
[Fig. 8] Fig. 8 is a diagram illustrating a configuration of an air-conditioning apparatus
0 according to Embodiment 4 of the present disclosure.
[Fig. 9] Fig. 9 is a diagram illustrating a configuration of an air-conditioning apparatus
0 according to Embodiment 5 of the present disclosure.
Description of Embodiments
[0009] Now, embodiments of an air-conditioning apparatus according to the present disclosure
will be described with reference to the drawings. In the drawings referred to below,
components that are denoted by the same reference symbols are the same or corresponding
components, and this applies to the entire embodiments described below. Moreover,
in the drawings, a relationship of sizes of components may be different from that
of actual ones. Further, modes of components described in the entire description are
mere examples, and the components are not limited to the modes given in the description.
In particular, combinations of the components are not limited to the combinations
in embodiments, and components described in one embodiment may be applied to another
embodiment. In addition, in terms of pressures and temperatures, the states of "high"
and "low" are not determined by comparing with any specific absolute values, but are
relatively determined based on the conditions or operations in the apparatus. Further,
with regard to a plurality of devices of the same type that are distinguished by suffixes,
in the case where the devices are not particularly required to be distinguished or
specified, the suffixes are omitted in some cases.
Embodiment 1
[0010] Fig. 1 is a schematic diagram illustrating an installation example of an air-conditioning
apparatus 0 according to Embodiment 1 of the present disclosure. Based on Fig. 1,
an installation example of an air-conditioning apparatus 0 according to Embodiment
1 will be described. The air-conditioning apparatus 0 includes a heat-source-side
refrigerant circulation circuit A in which a heat-source-side refrigerant is circulated
and a heat medium circulation circuit B in which a heat medium, such as water, which
stores and transfers heat is circulated. The air-conditioning apparatus 0 performs
air-conditioning by performing cooling/heating operation or other operation. The heat-source-side
refrigerant circulation circuit A functions as a heat-source-side device that heats
or cools the heat medium in the heat medium circulation circuit B.
[0011] In Fig. 1, the air-conditioning apparatus 0 according to Embodiment 1 includes one
outdoor unit 1 as a heat source apparatus, a plurality of indoor units 3 (indoor units
3a to 3c) as indoor devices, and a relay unit 2. The relay unit 2 is a unit that intermediates
heat transfer between the heat-source-side refrigerant circulating in the heat-source-side
refrigerant circulation circuit A and the heat medium circulating in the heat medium
circulation circuit B. The outdoor unit 1 and the relay unit 2 are connected by a
refrigerant pipe 6 that serves as a flow path of the heat-source-side refrigerant.
Here, a plurality of relay units 2 may be connected to one outdoor unit 1 in parallel.
[0012] Each of the indoor units 3 is connected to the relay unit 2 by way of a heat medium
main pipe 5 that serves as a flow path of the heat medium. Here, each of the indoor
units 3 is connected to the heat medium main pipe 5 via the heat medium branch pipe
51.
[0013] As the heat-source-side refrigerant to be circulated in the heat-source-side refrigerant
circulation circuit A, a single refrigerant such as R-22 or R-134a, a pseudo-azeotropic
refrigerant mixture such as R-410A or R-404A, or a non-azeotropic refrigerant mixture
such as R-407C may be used, for example. In addition, a refrigerant, or a mixture
thereof, having a double bond in the chemical formula, such as CF
3CF=CH
2, which has a relatively low global warming potential, or a natural refrigerant, such
as CO
2 or propane, may be used.
[0014] As the heat medium to be circulated in the heat medium circulation circuit B, brine
(antifreeze liquid), water, a mixture of brine and water, or a mixture of water and
an additive having a high anticorrosive effect may be used, for example. Thus, in
the air-conditioning apparatus 0 of Embodiment 1, a substance having high safety can
be used as the heat medium.
[0015] Fig. 2 is a diagram illustrating an example of a configuration of the air-conditioning
apparatus 0 according to Embodiment 1 of the present disclosure. Based on Fig. 2,
a configuration of devices provided in the air-conditioning apparatus 0 will be described.
As described above, the outdoor unit 1 is connected to the relay unit 2 by the refrigerant
pipe 6. Also, the indoor units 3 are connected to the relay unit 2 by the heat medium
main pipe 5. In Fig. 2, three indoor units 3 are connected to the relay unit 2 via
the heat medium main pipe 5. Note that the number of the indoor units 3 to be connected
is not limited to three.
<Outdoor Unit 1 >
[0016] The outdoor unit 1 is configured to transfer heat by circulating the heat-source-side
refrigerant in the heat-source-side refrigerant circulation circuit A and cause the
heat-source-side refrigerant to exchange heat with the heat medium at a heat medium
heat exchanger 21 of the relay unit 2. In Embodiment 1, cooling energy is transferred
by the heat-source-side refrigerant. The outdoor unit 1 includes, in the casing, a
compressor 10, a heat-source-side heat exchanger 12, an expansion device 13, and an
accumulator 14. The compressor 10, a refrigerant flow passage switching device 11,
the heat-source-side heat exchanger 12, and the accumulator 14 are connected by the
refrigerant pipe 6 and are installed in the outdoor unit 1. The compressor 10 is configured
to suck and compress the heat-source-side refrigerant and discharge the refrigerant
in a high-temperature, high-pressure state. Here, the compressor 10 may be, for example,
an inverter compressor, or a similar device, capable of controlling capacity. The
refrigerant flow passage switching device 11 is configured to switch flow paths of
the heat-source-side refrigerant depending on whether operation is in a cooling operation
mode or a heating operation mode. The refrigerant flow passage switching device 11
is not required to be installed if only a cooling operation or a heating operation
is performed.
[0017] The heat-source-side heat exchanger 12 is configured to cause heat exchange to be
performed between an outdoor air supplied by a heat-source-side fan 15 and the heat-source-side
refrigerant. In a heating operation mode, the heat-source-side heat exchanger 12 functions
as an evaporator, and causes the heat-source-side refrigerant to receive heat. In
a cooling operation mode, the heat-source-side heat exchanger 12 functions as a condenser
or radiator, and causes the heat-source-side refrigerant to reject heat. The expansion
device 13 functions as a pressure reducing valve and an expansion valve, and is configured
to decompress and expand the heat-source-side refrigerant. Here, the expansion device
13 may be, for example, an electronic expansion valve, or similar other devices, whose
opening degree can be variably controlled to arbitrarily adjust the flow rate of the
heat-source-side refrigerant. The accumulator 14 is installed on the sucking side
of the compressor 10. The accumulator 14 is configured to store excessive refrigerant
that is generated when, for example, the amount of refrigerant used in a heating operation
and that in a cooling operation is different or when operation changes and is in a
transition period. Note that there is a case where the accumulator 14 is not installed
in the heat-source-side refrigerant circulation circuit A.
<Indoor Unit 3>
[0018] The indoor units 3 are configured to supply air-conditioned air to indoor spaces.
Each indoor unit 3 of Embodiment 1 includes, in the casing, an indoor heat exchanger
31 (indoor heat exchangers 31 a to 31 c), an indoor flow control device 32 (indoor
flow control devices 32a to 32c) and an indoor-side fan 33 (indoor-side fans 33a to
33c). The indoor heat exchangers 31 and the indoor flow control devices 32 form part
of the heat medium circulation circuit B.
[0019] The indoor flow control device 32 is, for example, a two-way valve whose opening
degree (opening area) can be controlled. By adjusting the opening degree, the indoor
flow control device 32 controls the flow rate of the heat medium flowing into and
out from the indoor heat exchanger 31. Then, the indoor flow control device 32 adjusts
the flow rate of the heat medium to be passed through the indoor heat exchanger 31
based on the temperature of the heat medium flowing into the indoor unit 3 and the
temperature of the heat medium flowing out from the indoor unit 3, so that the indoor
heat exchanger 31 can cause heat exchange to be performed with an appropriate quantity
of heat for a heat load of the indoor space. When the indoor heat exchanger 31 does
not need to cause heat exchange to be performed with a heat load, such as when operation
is stopped or in a thermos-off state, the indoor flow control device 32 can close
the valve completely to stop supply of the heat medium to the indoor heat exchanger
31. In Fig. 2, the indoor flow control device 32 is installed on the pipe on the outlet
side to which the indoor heat exchanger 31 discharges the heat medium, but the configuration
is not limited thereto. For example, the indoor flow control device 32 may be installed
on the inlet side from which the indoor heat exchanger 31 incorporates the heat medium.
[0020] Furthermore, the indoor heat exchanger 31 has, for example, heat-transfer tubes and
fins. The heat medium passes through the heat-transfer tubes of the indoor heat exchanger
31. The indoor heat exchanger 31 is configured to cause heat exchange to be performed
between air of the indoor space supplied from the indoor-side fan 33 and the heat
medium. When the heat medium having a temperature cooler than the air passes through
the heat-transfer tubes, the air is cooled, and the indoor space is thus cooled. The
indoor-side fan 33 is configured to cause the air of the indoor space to pass through
the indoor heat exchanger 31 and generate an air flow that causes the air to return
to the indoor space.
<Relay Unit 2>
[0021] Next, a configuration of the relay unit 2 will be described. The relay unit 2 includes
devices that are used to transfer heat between the heat-source-side refrigerant circulating
in the heat-source-side refrigerant circulation circuit A and the heat medium circulating
in the heat medium circulation circuit B. The relay unit 2 includes a heat medium
heat exchanger 21 and a pump 22.
[0022] The heat medium heat exchanger 21 is configured to cause heat exchange to be performed
between the heat-source-side refrigerant and the heat medium to transfer heat to the
heat medium from the heat-source-side refrigerant. The heat medium heat exchanger
21 functions as a condenser or a radiator, and is configured to reject heat to the
heat-source-side refrigerant when heating the heat medium. When cooling the heat medium,
the heat medium heat exchanger 21 functions as an evaporator, and is configured to
cause the heat-source-side refrigerant to receive heat. The pump 22 is configured
to suck the heat medium and apply pressure thereto to cause the heat medium to circulate
in the heat medium circulation circuit B. Here, the pump 22 can control capacity,
and can thus adjust the flow rate of the heat medium circulating (volume of the heat
medium flowing per unit time) in the heat medium circulation circuit B according to
the magnitude of a heat load in each indoor unit 3.
[0023] Now, operations of the devices on the heat-source-side refrigerant circulation circuit
A side of the air-conditioning apparatus 0 will be described based on the flow of
the heat-source-side refrigerant circulating in the heat-source-side refrigerant circulation
circuit A. First, a case where the heat medium is cooled will be described. The compressor
10 sucks and compresses the heat-source-side refrigerant, and then discharges the
refrigerant in a high-temperature, high-pressure state. The discharged heat-source-side
refrigerant flows into the heat-source-side heat exchanger 12 via the refrigerant
flow passage switching device 11. The heat-source-side heat exchanger 12 causes heat
exchange to be performed between air supplied by the heat-source-side fan 15 and the
heat-source-side refrigerant, and condenses and liquefies the heat-source-side refrigerant.
The condensed and liquefied heat-source-side refrigerant passes through the expansion
device 13. When the condensed and liquefied heat-source-side refrigerant passes through
the expansion device 13, the expansion device 13 decompresses the refrigerant. The
decompressed heat-source-side refrigerant then flows out from the outdoor unit 1,
passes through the refrigerant pipe 6, and flows into the heat medium heat exchanger
21 of the relay unit 2. The heat medium heat exchanger 21 causes heat exchange to
be performed between the heat-source-side refrigerant passing therein and the heat
medium to evaporate and gasify the heat-source-side refrigerant. At this time, the
heat medium is cooled. The heat-source-side refrigerant flowed out of the heat medium
heat exchanger 21 flows out from the relay unit 2, passes through the refrigerant
pipe 6, and flows into the outdoor unit 1. Then, after passing through the refrigerant
flow passage switching device 11 again, the heat-source-side refrigerant, which has
been evaporated and gasified, is sucked into the compressor 10.
[0024] Next, a case where the heat medium is heated will be described. The compressor 10
sucks and compresses the heat-source-side refrigerant, and then discharges the refrigerant
in a high-temperature, high-pressure state. The discharged heat-source-side refrigerant
flows out from the outdoor unit 1 via the refrigerant flow passage switching device
11, passes through the refrigerant pipe 6, and flows into the heat medium heat exchanger
21 of the relay unit 2. The heat medium heat exchanger 21 causes heat exchange to
be performed between the heat-source-side refrigerant passing therein and the heat
medium to condense and liquefy the heat-source-side refrigerant. At this time, the
heat medium is heated. The condensed and liquefied heat-source-side refrigerant flowed
out of the heat medium heat exchanger 21 flows out from the relay unit 2, passes through
the refrigerant pipe 6, and passes through the expansion device 13 of the outdoor
unit 1. When the condensed and liquefied heat-source-side refrigerant passes through
the expansion device 13, the expansion device 13 decompresses the refrigerant. The
decompressed heat-source-side refrigerant then flows into the heat-source-side heat
exchanger 12. The heat-source-side heat exchanger 12 causes heat exchange to be performed
between air supplied by the heat-source-side fan 15 and the heat-source-side refrigerant
to evaporate and gasify the heat-source-side refrigerant. Then, after passing through
the refrigerant flow passage switching device 11 again, the heat-source-side refrigerant,
which has been evaporated and gasified, is sucked into the compressor 10.
[0025] In the air-conditioning apparatus 0, various sensors are provided as detection devices
to detect physical quantities. In the heat-source-side refrigerant circulation circuit
A, a discharge temperature sensor 501, a discharge pressure sensor 502, and an outdoor
temperature sensor 503 are installed on the outdoor unit 1 side. The discharge temperature
sensor 501 is configured to detect the temperature of the refrigerant discharged from
the compressor 10 and output a discharge temperature detection signal. An outdoor
unit control device 100, which will be described later, receives the discharge temperature
detection signal output from the discharge temperature sensor 501. Here, the discharge
temperature sensor 501 includes a thermistor or other similar devices. Other temperature
sensors, which will be described below, are assumed to also include thermistors or
other similar devices. The discharge pressure sensor 502 is configured to detect the
pressure of the refrigerant discharged from the compressor 10 and output a discharge
pressure detection signal. The outdoor unit control device 100, which will be described
later, receives the discharge pressure detection signal output from the discharge
pressure sensor 502. The outdoor temperature sensor 503 is installed in an air inflow
portion of the heat-source-side heat exchanger 12 in the outdoor unit 1. The outdoor
temperature sensor 503 is configured to detect, for example, an outdoor temperature,
which is the temperature of air around the outdoor unit 1, and output an outdoor temperature
detection signal. The outdoor unit control device 100, which will be described later,
receives the outdoor temperature detection signal output from the outdoor temperature
sensor 503.
[0026] Furthermore, in the heat-source-side refrigerant circulation circuit A, a first
refrigerant temperature sensor 504 and a second refrigerant temperature sensor 505
are installed on the relay unit 2 side. The first refrigerant temperature sensor 504
is installed in a pipe on the refrigerant inflow side of the heat medium heat exchanger
21 in the flow of the refrigerant in the heat-source-side refrigerant circulation
circuit A generated when the heat medium is cooled. The first refrigerant temperature
sensor 504 and the second refrigerant temperature sensor 505 are configured to detect
the temperature of the refrigerant flowing into the heat medium heat exchanger 21
and that of the refrigerant flowing out from the heat medium heat exchanger 21, and
output refrigerant-side detection signals. A relay unit control device 200, which
will be described later, receives the refrigerant-side detection signals output from
the first refrigerant temperature sensor 504 and the second refrigerant temperature
sensor 505.
[0027] Meanwhile, in the heat medium circulation circuit B, a heat medium inflow port side
temperature sensor 511 and a heat medium outflow port side temperature sensor 512
are installed on the relay unit 2 side. The heat medium inflow port side temperature
sensor 511 is installed in a pipe on the heat medium inflow side of the heat medium
heat exchanger 21 in the flow of the heat medium in the heat medium circulation circuit
B. The heat medium inflow port side temperature sensor 511 is configured to detect
the temperature of the heat medium flowing into the heat medium heat exchanger 21
and output a heat medium inflow side detection signal. The relay unit control device
200, which will be described later, receives the heat medium inflow-side detection
signal output from the heat medium inflow port side temperature sensor 511. The heat
medium outflow port side temperature sensor 512 is installed in a pipe on the heat
medium outflow side of the heat medium heat exchanger 21 in the flow of the heat medium
in the heat medium circulation circuit B. The heat medium outflow port side temperature
sensor 512 is configured to detect the temperature of the heat medium flowing out
from the heat medium heat exchanger 21 and output a heat medium outflow side detection
signal. The relay unit control device 200, which will be described later, receives
the heat medium outflow side detection signal output from the heat medium outflow
port side temperature sensor 512. Detection sensors, such as a pressure sensor and
a flow rate sensor, may be installed on the relay unit 2 side in the heat medium circulation
circuit B, although the air-conditioning apparatus 0 of Embodiment 1 is not provided
with such detection units.
[0028] In the heat medium circulation circuit B, an indoor inflow port side temperature
sensor 513 (indoor inflow port side temperature sensors 513a to 513c) is installed
on each indoor unit 3 side. In addition, an indoor outflow port side temperature sensor
514 (indoor outflow port side temperature sensors 514a to 514c) is also installed.
The indoor inflow port side temperature sensor 513 is configured to detect the temperature
of the heat medium flowing into the indoor heat exchanger 31 and output an inflow
side detection signal. An indoor unit control device 300, which will be described
later, installed in each indoor unit 3 receives the inflow side detection signal output
from the corresponding indoor outflow port side temperature sensor 514. Each indoor
outflow port side temperature sensor 514 is configured to detect the temperature of
the heat medium flowing out from the indoor heat exchanger 31 and output an outflow
side detection signal. The indoor unit control device 300, which will be described
later, receives the inflow side detection signal output from the corresponding indoor
outflow port side temperature sensor 514.
[0029] Furthermore, in the heat medium circulation circuit B, an indoor inflow side pressure
sensor 521 (indoor inflow side pressure sensors 521a to 521c) is installed on the
indoor unit 3 side. In addition, an indoor outflow side pressure sensor 522 (indoor
outflow side pressure sensors 522a to 522c) is also installed. The indoor inflow side
pressure sensor 521 and the indoor outflow side pressure sensor 522 are installed
on the heat medium inflow side and the heat medium outflow side, respectively, of
the indoor flow control device 32 in each indoor unit 3, and are configured to output
signals corresponding to the detected pressure values. The indoor unit control device
300, which will be described later, provided in each indoor unit 3 receives the signals
corresponding to the pressure values output from the indoor inflow side pressure sensor
521 and the indoor outflow side pressure sensor 522.
[0030] Here, when the relay unit 2 is provided with, for example, a pressure sensor that
detects the entire pressure of the heat medium circulating in the heat medium circulation
circuit B, the indoor inflow side pressure sensor 521 may be omitted. Further, a flow
rate detection device that detects flow rate may be installed in place of a pressure
sensor. Furthermore, a heat quantity detection device capable of detecting a quantity
of heat involved in heat exchange with air of the indoor space, in which a heat load
is present, may be installed.
[0031] Each indoor unit control device 300 is configured to obtain, by calculation or other
similar operation, a quantity of heat involved in heat exchange at the indoor heat
exchanger 31. Each indoor unit control device 300 is configured to send signals containing
the obtained heat quantity to the relay unit control device 200.
[0032] In addition, an indoor temperature sensor 515 (indoor temperature sensors 515a to
515c) is installed on each indoor unit 3 side. The indoor temperature sensor 515 is
configured to detect a suction temperature, which is the temperature of air that is
caused to flow into the indoor heat exchanger 31 by an air flow generated by driving
the indoor-side fan 33, and output a suction temperature detection signal. Here, the
suction temperature may be the temperature of indoor air in the indoor space, in which
a heat load is present.
[0033] Next, a configuration of control system devices in the air-conditioning apparatus
0 of Embodiment 1 of the present disclosure will be described. As shown in Fig. 2,
each unit includes a controller that controls devices in the unit. Each controller
is configured to perform processing based on data on physical quantities included
in the signals sent from various sensors and based on the signals of instructions
and settings sent from input devices (not shown) or other similar devices. Here, each
of the controllers is connected to other controllers via wired communication connection
or wireless communication connection and is capable of communicating with other control
units via signals containing various data. The outdoor unit 1 includes the outdoor
unit control device 100. The relay unit 2 includes the relay unit control device 200.
Each of the indoor units 3 includes the indoor unit control device 300 (indoor unit
control devices 300a to 300c).
[0034] For communication in Embodiment 1, each indoor unit control device 300 can send,
to the relay unit control device 200 of the relay unit 2, signals, which contain data
on pressure, temperature and other variables detected by the sensors in the corresponding
indoor unit 3. In addition, each indoor unit control device 300 can also send, to
the relay unit control device 200 of the relay unit 2, data on indoor set temperature
input from a remote control (now shown), and data obtained by arithmetic processing
as described later, such as a flow rate of the heat medium passing through the corresponding
indoor heat exchanger 31 and a heat quantity involved in heat exchange in the indoor
heat exchanger 31 with air of the indoor space.
[0035] Now, calculations of the indoor unit control device 300 for a flow rate of the heat
medium passing through the indoor heat exchanger 31 and for a heat quantity involved
in heat exchange at the indoor heat exchanger 31 with air of the indoor space will
be described. By using pressure values detected by the indoor inflow side pressure
sensor 521 and the indoor outflow side pressure sensor 522, the indoor unit control
device 300 can calculate a pressure difference between the pressure of the heat medium
before passing through the indoor flow control device 32 and that after passing through
the indoor flow control device 32. The indoor unit control device 300 can also calculate
a flow rate of the heat medium passing through the indoor heat exchanger 31 by using,
at least, the pressure difference and a Cv value that represents features of the valve
of the indoor flow control device 32. Here, the Cv value is a value determined by
the type and the port diameter of the valve of a flow control device, and is a capacity
coefficient of the valve. The Cv value is a numerical value representing a flow rate
of fluid passing through a valve with a certain pressure difference. Furthermore,
from temperatures detected by the indoor inflow port side temperature sensor 513 and
the indoor outflow port side temperature sensor 514 and the flow rate of the heat
medium passing through the indoor heat exchanger 31, a heat quantity involved in heat
exchange in the indoor heat exchanger 31 with air of the indoor space can be calculated.
[0036] Calculation of a heat quantity at each indoor unit control device 300 will be described.
First, each controller obtains the Cv value based on the opening degree of the valve
of the corresponding flow control device. Based on the Cv value and the pressure difference
between the pressure of the heat medium before passing through the flow control device
and that of after passing through the flow control device, a flow rate of the heat
medium passing through the heat exchanger and the flow control device is calculated.
Here, the flow rate of the heat medium increases as the Cv value increases. In addition,
the flow rate of the heat medium also increases when the pressure difference of the
heat medium is large. Then, based on the flow rate of the heat medium flowing in the
corresponding heat exchanger and a temperature difference between the temperature
of the heat medium flowing into the heat exchanger and that of the heat medium flowing
out from the heat exchanger, a heat quantity supplied to a heat load through heat
exchange is calculated. The supplied heat quantity increases as the flow rate of the
heat medium passing through the heat exchanger increases. In addition, the supplied
heat quantity increases when the temperature difference of the heat medium before
and after the heat exchange is large. Then, the controller of each unit compares the
calculated heat quantity supplied to the heat load with a required capacity (a heat
quantity required for supplying to the heat load), and when the required capacity
is larger, the opening degree of the corresponding flow control device is increased.
Furthermore, when the total of the calculated heat quantities is less than the total
of the required capacities of all the indoor units 3, output of the pump 22 of the
relay unit 2 is increased, driving frequency of the compressor 10 of the outdoor unit
1 is increased, or other operations for increasing the heat quantities are performed.
[0037] Fig. 3 is a diagram illustrating a configuration of the relay unit control device
200 according to Embodiment 1 of the present disclosure. As described above, processing
associated with controls in Embodiment 1 is performed by the relay unit control device
200. The relay unit control device 200 includes a control processing device 210, a
memory device 220, a clocking device 230, and a communication device 240.
[0038] The memory device 220 stores data that the control processing device 210 uses in
processing. The memory device 220 includes a volatile memory device (not shown), such
as a random access memory (RAM), which can temporarily store data and a non-volatile
auxiliary memory device (not shown), such as a flash memory, which can store data
for a long time. In addition, the memory device 220 stores programs. The control processing
device 210 performs processing based on the programs to achieve processing in each
unit of the control processing device 210.
[0039] The clocking device 230 includes a timer and measures a time period that the control
processing device 210 uses for calculation or other operation. The communication device
240 is an interface between the control processing device 210 and controllers of other
units, and is configured to convert signals containing data when performing communication
by the signals therebetween. Hereinafter, communication between the control processing
device 210 and controllers of other units is assumed to be performed via the communication
device 240.
[0040] The control processing device 210 includes a temperature gradient setting processing
unit 211, a calculation processing unit 212, a determination processing unit 213,
and a heat-source-side control processing unit 214. The temperature gradient setting
processing unit 211 is configured to generate a target temperature gradient for each
indoor unit 3 from data, which are data on a suction temperature at start of operation
of the indoor unit 3 and data on an indoor set temperature of the indoor unit 3 sent
from the indoor unit control device 300 of the indoor unit 3. Then, one of the generated
target temperature gradients is set as a reference (hereinafter referred to as reference
temperature gradient). In controlling the heat-source-side refrigerant circulation
circuit A, the reference temperature gradient is used to determine the temperature
of heat medium involved in heat exchange in the heat medium heat exchanger 21. As
described above, the suction temperature is detected by the indoor temperature sensor
515 and is the temperature of air in the indoor space. The calculation processing
unit 212 is configured to calculate a temperature difference of suction temperatures
in each indoor unit 3 at a predetermined time interval. Based on a condition of air
of the indoor space, in which a heat load is present, in each indoor unit 3, the condition
of air being obtained from the calculated temperature difference, the determination
processing unit 213 determines whether or not the temperature of the heat medium is
changed. Then, the heat-source-side control processing unit 214 provides an instruction
based on the processing performed by the determination processing unit 213 to a device
on the heat-source-side refrigerant circulation circuit A side to control the heat-source-side
refrigerant circulation circuit A. More specifically, processing such as control processing
is performed by sending a signal of an instruction to change the driving frequency
of the compressor 10 or other signal to the outdoor unit control device 100 of the
outdoor unit 1. Then, by changing an evaporation temperature or a condensation temperature
of the heat-source-side refrigerant in the heat medium heat exchanger 21, the temperature
of the heat medium flowing out from the heat medium heat exchanger 21 is changed.
Here, the control processing device 210 includes, for example, a microcomputer having
a control arithmetic processing device such as a central processing unit (CPU).
[0041] In Embodiment 1, the relay unit control device 200 performs processing based on
data sent from the indoor unit control device 300 and sends an instruction to the
outdoor unit control device 100 to control the heat-source-side refrigerant circulation
circuit A. In this description, processing in Embodiment 1 is performed mainly by
the relay unit control device 200, but the processing may be performed by other device.
One or a plurality of controllers among the outdoor unit control device 100 and the
indoor unit control devices 300 may perform control or other processing. A controller
provided outside the units may perform control or other processing. In addition, for
example, the processing to be performed by the calculation processing unit 212 may
be performed by each of the indoor unit control devices 300, and the processing to
be performed by the heat-source-side control processing unit 214 may be performed
by the outdoor unit control device 100.
[0042] Next, operation of the air-conditioning apparatus 0 will be described. The outdoor
unit 1 causes the heat-source-side refrigerant to circulate between the outdoor unit
1 and the relay unit 2 via the refrigerant pipe 6. At this time, the heat-source-side
refrigerant exchanges heat with the heat medium when passing through the heat medium
heat exchanger 21 in the relay unit 2, which will be described later. The heat medium
is heated or cooled through the heat exchange. In Embodiment 1, the heat-source-side
refrigerant is assumed to be heated and the heat medium is assumed to be cooled.
[0043] By using the pump 22, which will be described later, the heat medium cooled in the
relay unit 2 is circulated by passing through the heat medium main pipes 5 and the
indoor units 3. At this time, the heat medium exchanges heat with air supplied by
a fan at the indoor heat exchanger 31 in the indoor unit 3, which will be described
later. The air having been subjected to the heat exchange with the heat medium is
supplied for air-conditioning in the indoor space.
[0044] Fig. 4 is a flowchart illustrating a control performed by the relay unit control
device 200 according to Embodiment 1 of the present disclosure. Based on Fig. 4, the
control of the air-conditioning apparatus 0 in Embodiment 1 will be described. Here,
the control processing device 210 of the relay unit control device 200 performs control
related processing.
[0045] The temperature gradient setting processing unit 211 of the control processing device
210 generates a target temperature gradient as data for each indoor unit 3 based on
the data of suction temperature and indoor set temperature sent from the indoor unit
control device 300 of the indoor unit 3 (step S1). A method or formula for calculating
a target temperature gradient are not particularly limited. For example, a formula
for target temperature gradient is represented by (Tp-T0)/ta when a suction temperature
T0 at start of operation is brought to an indoor set temperature Tp in a predetermined
time period ta. Here, target temperature gradients for the indoor units 3 are calculated
by using the same method or formula so that process does not become complicated. At
this time, because a suction temperature and an indoor set temperature may be different
for each indoor unit 3, a target temperature gradient may be different for each indoor
unit 3. In addition, the time period ta represents an ideal time period for making
the temperature of air in an indoor space reach the set temperature. For example,
the time period ta is such a time period that a person in an indoor space does not
feel uncomfortable when the air temperature reaches the set temperature within the
time period ta.
[0046] Among the temperature gradients of the indoor units 3, the temperature gradient with
the largest slope is set as a reference temperature gradient by the temperature gradient
setting processing unit 211 (step S2). Therefore, by setting the reference temperature
gradient regarding a largest heat load, a sufficient quantity of heat is supplied
to cover the heat loads of all the indoor units 3.
[0047] The temperature gradient setting processing unit 211 determines the temperature
of the heat medium involved in heat exchange in the heat medium heat exchanger 21
based on the set target temperature gradient (step S3). For example, in a cooling
operation, the temperature gradient setting processing unit 211 sets the temperature
of the heat medium to decrease as the temperature gradient increases. Thus, a target
evaporation temperature for the heat-source-side refrigerant in the heat medium heat
exchanger 21 is set to a low temperature. In a heating operation, the temperature
gradient setting processing unit 211 sets the temperature of the heat medium so to
increase as the temperature gradient increases. Thus, a target condensation temperature
for the heat-source-side refrigerant in the heat medium heat exchanger 21 is set to
be a high temperature.
[0048] To make the heat medium reach the temperature determined by the temperature gradient
setting processing unit 211, the heat-source-side control processing unit 214 provides
an instruction to a device on the heat-source-side refrigerant circulation circuit
A side to control and operate the heat-source-side refrigerant circulation circuit
A (step S4).
[0049] Then, the calculation processing unit 212 of the control processing device 210 determines
whether or not a set time period has elapsed (step S5). In Embodiment 1, a temperature
difference is calculated with a set time period of one minute, but the set time period
is not limited to one minute.
[0050] Furthermore, the calculation processing unit 212 calculates a temperature difference
between suction temperatures for each indoor unit 3 at a predetermined time interval
(step S6). At this time, a temperature T at a time t is represented by a liner function
(1).
[0051] Then, the determination processing unit 213 determines whether or not to change
the temperature of the heat medium involved in heat exchange in the heat medium heat
exchanger 21 based on the change in temperature of the indoor air obtained from the
temperature difference calculated by the calculation processing unit 212 (step S7).
[0052] When, for example, determining that the temperature difference is out of a temperature
difference threshold range, the determination processing unit 213 determines the temperature
of the heat medium involved in heat exchange in the heat medium heat exchanger 21
(step S8). Here, in Embodiment 1, an upper limit and a lower limit for the temperature
difference threshold range are set to be plus or minus one degree Celsius. However,
the upper and lower limits are not limited to these values. For example, the upper
and lower limits of the temperature difference threshold range may be set within a
range of plus or minus 0.5 to one degree Celsius.
[0053] Then, to make the temperature of the heat medium reach the temperature determined
by the determination processing unit 213, the heat-source-side control processing
unit 214 provides an instruction to a device on the heat-source-side refrigerant circulation
circuit A side to control and operate the heat-source-side refrigerant circulation
circuit A (step S9). Here, the determination processing unit 213 in Embodiment 1 determines
to change the temperature of the heat medium by two degrees Celsius. However, the
change of the temperature is not limited to two degrees Celsius, and the temperature
to be determined may be changed. For example, based on the horsepower of the compressor
10 of the outdoor unit 1, an interval of the temperature of the heat medium to be
changed may be determined.
[0054] Meanwhile, when it is determined that the temperature difference is equal to or larger
than the temperature difference threshold value, the temperature of the heat medium
is not changed (step S10).
[0055] The calculation processing unit 212 and the determination processing unit 213 continue
the processing of steps S5 to S10 until it is determined that the temperatures of
the air of the indoor spaces of all the indoor units 3 involving in operation reach
the indoor set temperatures (step S11).
[0056] Fig. 5 shows graphs illustrating an example of an operation result of the air-conditioning
apparatus 0 according to Embodiment 1 of the present disclosure. Fig. 5 illustrates
a case where the indoor units 3 of the air-conditioning apparatus 0 perform cooling
operation. In Fig. 5, the target temperature gradient of the indoor unit 3a is set
as a reference temperature gradient. As illustrated in Fig. 5, when the temperature
of the indoor space approaches the set temperature, the temperature of the indoor
space is controlled in such a manner that the temperature of the indoor space changes
along the target temperature gradient by increasing an evaporation temperature and
thus changing the temperature of the heat medium.
[0057] As described above, the target temperature gradient for the largest load is set as
a reference temperature gradient, and the temperature of the heat medium supplied
to the indoor units 3 is determined based on the gradient. As a result, in the indoor
unit 3 having a small heat load, the temperature reaches the set temperature faster
than the indoor unit 3 that supplies heat to a largest heat load. In Fig. 5, in the
indoor spaces of the indoor units 3b and 3c, in which heat loads are required, the
temperatures reach the set temperatures faster than the indoor space of the indoor
unit 3a, which is subjected to air-conditioning. Thus, in the indoor units 3 in which
the temperatures of the air of the indoor spaces, in which heat load are present,
reach the set temperatures, the indoor unit control device 300 controls to close the
indoor flow control devices 32. By closing the indoor flow control devices 32, the
heat medium is not allowed to pass through the indoor heat exchangers 31, and thus
supply of heat is stopped and the temperatures of the air of the indoor spaces are
controlled not to decrease below the set temperatures.
[0058] In a related art chiller, indoor conditions are not reflected in control of heat
supply to a heat medium, such as water. Thus, heat is supplied while the temperature
of the heat medium is maintained at a constant level. According to the air-conditioning
apparatus 0 of Embodiment 1, among the indoor units 3, the outdoor unit 1 and the
relay unit 2, signals containing data on the detected physical quantities, such as
temperatures, flow rates, and heat quantities, can be exchanged. In addition, data
indicating indoor conditions of the indoor units 3 can be sent to other units. Thus,
in the air-conditioning apparatus 0, based on the conditions of air-conditioning in
the indoor units 3 and the conditions of the indoor spaces, control such as change
of temperature of the heat medium can be performed in cooperation with devices on
the heat-source-side refrigerant circulation circuit A side. Consequently, the air-conditioning
apparatus 0 can achieve energy saving.
[0059] For example, target temperature gradients of the indoor units 3 are obtained by using
the temperatures of air of the indoor spaces detected by the indoor temperature sensors
515, which are installed in the respective indoor units 3, and the set temperatures
set for the respective indoor units 3, and among the target temperature gradients,
a reference temperature gradient is set. Based on the set target temperature gradient,
the temperature of the heat medium involved in heat exchange in the heat medium heat
exchanger 21 is determined and the heat-source-side refrigerant circulation circuit
A is operated to obtain the determined temperature. Then, based on the detected changes
in the indoor temperatures in the indoor units 3, it is determined whether or not
to change the temperature of the heat medium. As described above, by changing the
temperature of the heat medium, the temperatures of air of the indoor spaces, in which
heat loads are present, are controlled. As a result, power consumption can be reduced,
and thus energy saving can be achieved. Here, it is preferred that a target temperature
gradient have such a gradient that the temperature of the indoor air is slowly brought
to the indoor set temperature. The reason is because a slow temperature adjustment
is easy to control and saves energy. In addition, by controlling the heat-source-side
refrigerant circulation circuit A based on the temperature changes of indoor air,
the temperatures of the indoor spaces and the temperature of the heat medium can be
controlled with certain widths.
Embodiment 2
[0060] Fig. 6 is a diagram illustrating an example of a configuration of an air-conditioning
apparatus 0 according to Embodiment 2 of the present disclosure. Now, the air-conditioning
apparatus 0 according to Embodiment 2 of the present disclosure will be described.
Here, the devices having the same functions and operations as those of Embodiment
1 are denoted by the same reference symbols.
[0061] In Embodiment 2, the outdoor unit 1 and the relay unit 2 are connected by using two
refrigerant pipes 6, and the relay unit 2 and each of the indoor units 3a to 3c are
connected by using two heat medium branch pipes 51. Because, as described above, two
pipes are used to connect between the outdoor unit 1 and the relay unit 2, and between
the relay unit 2 and each of the indoor units 3a to 3c, installation of the air-conditioning
apparatus 0 can be facilitated.
<Outdoor Unit 1 >
[0062] Similarly to Embodiment 1, the outdoor unit 1 includes the compressor 10, the refrigerant
flow passage switching device 11, the heat-source-side heat exchanger 12, the accumulator
14, and the heat-source-side fan 15. The outdoor unit 1 of Embodiment 2 further includes
a first connection pipe 16, a second connection pipe 17, and first backflow prevention
devices 18a to 18d. Here, as the backflow prevention devices 18a to 18d, check valves
are used. The first backflow prevention device 18a is configured to prevent backflow
of the refrigerant, which is in a high-temperature, high-pressure gaseous state, from
the first connection pipe 16 toward the heat-source-side heat exchanger 12 in a heating-only
operation mode and a heating-main operation mode. The first backflow prevention device
18b is configured to prevent backflow of the refrigerant, which is in a high-pressure
liquid or gas-liquid two-phase state, from the first connection pipe 16 toward the
accumulator 14 in a cooling-only operation mode and a cooling main operation mode.
The first backflow prevention device 18c is configured to prevent backflow of the
refrigerant, which is in a high-pressure liquid or gas-liquid two-phase state, from
the second connection pipe 17 toward the accumulator 14 in a cooling-only operation
mode and a cooling main operation mode. The first backflow prevention device 18d is
configured to prevent backflow of the refrigerant, which is in a high-temperature,
high-pressure gaseous state, from the flow path on the discharge side of the compressor
10 toward the second connection pipe 17 in a heating-only operation mode and a heating-main
operation mode.
[0063] As described above, because the first connection pipe 16, the second connection pipe
17 and the first backflow prevention devices 18a to 16 are provided, the flow of the
refrigerant into the relay unit 2 is maintained in a constant direction regardless
of any operation that the indoor unit 3 requests. Although check valves are used as
the first backflow prevention devices 18a to 16, other device capable of preventing
backflow of refrigerant may be used. For example, as the first backflow prevention
devices 18a to 18d, opening and closing devices, expansion devices having a complete
closing function, or other similar devices may be used.
<Relay Unit 2>
[0064] The relay unit 2 of Embodiment 2 includes two heat medium heat exchangers 21 and
two pumps 22, both of which are described in Embodiment 1. In addition, the relay
unit 2 includes two relay-side expansion devices 23, two opening and closing devices
24, and two relay-side refrigerant flow passage switching devices 25. The relay unit
2 also includes three first heat medium flow passage switching devices 26, three second
heat medium flow passage switching devices 27, and three heat medium flow control
devices 28 for each indoor unit 3.
[0065] The two heat medium heat exchangers 21 (a heat medium heat exchanger 21 a and a heat
medium heat exchanger 21b) of Embodiment 2 are configured to function as condensers
(radiators) or evaporators. The heat medium heat exchanger 21a is installed between
a relay-side expansion device 23a and a relay-side refrigerant flow passage switching
device 25a in the heat-source-side refrigerant circulation circuit A, and serves as
a heat exchanger that heats the heat medium in a cooling and heating mixed operation
mode. The heat medium heat exchanger 21b is installed between a relay-side expansion
device 23b and a relay-side refrigerant flow passage switching device 25b in the heat-source-side
refrigerant circulation circuit A, and serves as a heat exchanger that cools the heat
medium in a cooling and heating mixed operation mode.
[0066] The two relay-side expansion devices 23 (the relay-side expansion device 23a and
the relay-side expansion device 23b) are configured to function as pressure reducing
valves and expansion valves, and decompress and expand the heat-source-side refrigerant.
The relay-side expansion device 23a is provided on an upstream side of the heat medium
heat exchanger 21a in the direction of flow of the heat-source-side refrigerant in
a cooling operation. The relay-side expansion device 23b is provided on an upstream
side of the heat medium heat exchanger 21b in the direction of flow of the heat-source-side
refrigerant in a cooling operation. The two relay-side expansion devices 23 may be,
for example, electronic expansion valves, or other similar devices, whose opening
degrees can be controlled.
[0067] The two opening and closing devices 24 (an opening and closing device 24a and opening
and closing device 24b) are formed of two-way valves or other similar devices, and
are configured to open and close the refrigerant pipes 6. The opening and closing
device 24a is installed on the refrigerant pipe 6 on the inflow side of the heat-source-side
refrigerant. The opening and closing device 24b is installed on a pipe that connects
the refrigerant pipe 6 on an inlet side of the heat-source-side refrigerant and the
refrigerant pipe 6 on an outlet side thereof. The two relay-side refrigerant flow
passage switching devices 25 (a relay-side refrigerant flow passage switching device
25a and a relay-side refrigerant flow passage switching device 25b) are formed of
four-way valves or other similar devices, and are configured to switch the flows of
the heat-source-side refrigerant based on the operation mode. The relay-side refrigerant
flow passage switching device 25a is installed on a downstream side of the heat medium
heat exchanger 21a in the direction of flow of the heat-source-refrigerant in a cooling
operation. The relay-side refrigerant flow passage switching device 25b is installed
on a downstream side of the heat medium heat exchanger 21b in the direction of flow
of the heat-source-refrigerant in a cooling-only operation.
[0068] The two pumps 22 (a pump 22a and a pump 22b) are configured to pressurize the heat
medium flowing in the heat medium main pipe 5 to cause the heat medium to be circulated
in the heat medium circulation circuit B. The pump 22a is installed on the heat medium
main pipe 5 between the heat medium heat exchanger 21a and the second heat medium
flow passage switching device 27. The pump 22b is installed on the heat medium main
pipe 5 between the heat medium heat exchanger 21b and the second heat medium flow
passage switching device 27.
[0069] The three first heat medium flow passage switching devices 26 (the first heat medium
flow passage switching devices 26a to 26c) are formed of three-way valves or other
similar devices, and are configured to switch the flow paths of the heat medium. The
number of the first heat medium flow passage switching devices 26 to be provided corresponds
to the number of the installed indoor units 3 (three in this embodiment). One of the
three flow paths of the first heat medium flow passage switching device 26 is connected
to the heat medium heat exchanger 21a. Another thereof is connected to the heat medium
heat exchanger 21b. The other thereof is connected to the heat medium flow control
device 28. The first heat medium flow passage switching devices 26 are installed on
the heat medium flow paths on the outlet sides of the indoor heat exchangers 31. In
Fig. 6, the first heat medium flow passage switching devices 26a, 26b, and 26c are
illustrated in this order from the bottom of the sheet in correspondence with the
indoor units 3.
[0070] The three second heat medium flow passage switching devices 27 (the second heat medium
flow passage switching devices 27a to 27c) are formed of three-way valves or other
similar devices, and are configured to switch the flow paths of the heat medium. The
number of the second heat medium flow passage switching devices 27 to be provided
corresponds to the number of the installed indoor units 3 (three in this embodiment).
One of the three flow paths of the second heat medium flow passage switching device
27 is connected to the heat medium heat exchanger 21a. Another thereof is connected
to the heat medium heat exchanger 21b. The other thereof is connected to the indoor
heat exchanger 31. The second heat medium flow passage switching devices 27 are installed
on the heat medium flow paths on the inlet sides of the indoor heat exchangers 31.
In Fig. 6, the second heat medium flow passage switching devices 27a, 27b, and 27c
are illustrated in this order from the bottom of the sheet in correspondence with
the indoor units 3.
[0071] The three heat medium flow control devices 28 (heat medium flow control devices 28a
to 28c) are provided on the relay unit 2 side in place of the indoor flow control
devices 32 of Embodiment 1. The heat medium flow control devices 28 are formed of
two-way valves, or similar other devices, capable of controlling the opening areas,
and are configured to control flow rates of the heat medium flowing in the heat medium
branch pipes 51. The number of the heat medium flow control devices 28 to be provided
corresponds to the number of the installed indoor units 3 (three in this embodiment).
One end of the heat medium flow control device 28 is connected to the indoor heat
exchanger 31. The other end thereof is connected to the first heat medium flow passage
switching device 26. Here, the heat medium flow control devices 28 are installed on
the heat medium flow paths on the outlet sides of the indoor heat exchangers 31. However,
the heat medium flow control devices 28 may be installed on the heat medium flow paths
on the inlet sides of the indoor heat exchangers 31. In Fig. 6, the heat medium flow
control devices 28a, 28b, and 28c are illustrated in this order from the bottom of
the sheet in correspondence with the indoor units 3.
[0072] Now, various sensors to be installed will be described. As in the case of Embodiment
1, on the heat-source-side refrigerant circulation circuit A, the discharge temperature
sensor 501, the discharge pressure sensor 502, and the outdoor temperature sensor
503 are installed on the outdoor unit 1 side. On the relay unit 2 side on the heat-source-side
refrigerant circulation circuit A, as the first refrigerant temperature sensor 504,
a first refrigerant temperature sensor 504a and a first refrigerant temperature sensor
504b are installed to correspond to the two heat medium heat exchangers 21. Similarly,
as the second refrigerant temperature sensor 505, a second refrigerant temperature
sensor 505a and a second refrigerant temperature sensor 505b are installed in correspondence
with the two heat medium heat exchangers 21.
[0073] In Embodiment 2, heat-source-side refrigerant pressure sensors 506 (a heat-source-side
refrigerant pressure sensor 506a and a heat-source-side refrigerant pressure sensor
506b) are installed. The heat-source-side refrigerant pressure sensor 506a is configured
to detect the pressure of the heat-source-side refrigerant flowing into and flowing
out from the heat medium heat exchanger 21a. The heat-source-side refrigerant pressure
sensor 506b is configured to detect the pressure of the heat-source-side refrigerant
flowing between the heat medium heat exchanger 21b and the relay-side expansion device
23b.
[0074] Meanwhile, on the relay unit 2 side of the heat medium circulation circuit B, the
heat medium inflow port side temperature sensors 511 (a heat medium inflow port side
temperature sensor 511a and a heat medium inflow port side temperature sensor 511b)
and the heat medium outflow port side temperature sensors 512 (a heat medium outflow
port side temperature sensor 512a and a heat medium outflow port side temperature
sensor 512b) are installed.
[0075] In Embodiment 1, the indoor inflow side pressure sensor 521 (the indoor inflow side
pressure sensors 521a to 521c) and the indoor outflow side pressure sensor 522 (the
indoor outflow side pressure sensors 522a to 522c) are installed on the indoor unit
3 side. In the air-conditioning apparatus 0 of Embodiment 2, the indoor inflow side
pressure sensor 521 and the indoor outflow side pressure sensor 522 are installed,
respectively, on the heat medium inflow side and the heat medium outflow side of the
heat medium flow control device 28, which is installed in the relay unit 2 as the
indoor flow control device 32 in Embodiment 1, and are configured to send signals
corresponding to detected pressures.
[0076] Furthermore, similarly to Embodiment 1, on each indoor unit 3 side, the indoor inflow
port side temperature sensor 513 (indoor inflow port side temperature sensors 513a
to 513c), the indoor outflow port side temperature sensor 514 (indoor outflow port
side temperature sensors 514a to 514c), and the indoor temperature sensor 515 (indoor
temperature sensors 515a to 515c) are installed.
[0077] As operation modes of the air-conditioning apparatus 0 in Embodiment 2, there are
a cooling only mode, in which all operating indoor units 3 perform cooling operation,
and a heating only mode, in which all operating indoor units 3 perform heating operation.
In addition, there are a cooling-main operation mode, which is executed when cooling
load in the operating indoor units 3 is larger than heating load, and a heating-main
operation mode, which is executed when heating load in the operating indoor units
3 is larger than cooling load.
<Cooling-only operation Mode>
[0078] In a cooling-only operation mode, the refrigerant in a high-temperature, high-pressure
gaseous state discharged from the compressor 10 flows into the heat-source-side heat
exchanger 12 via the refrigerant flow passage switching device 11. In the heat-source-side
heat exchanger 12, the refrigerant is condensed and liquefied by rejecting heat to
ambient air, thereby changing into a high-pressure liquid state, and flows out from
the outdoor unit 1 via the first backflow prevention device 18a. Then, the refrigerant
flows into the relay unit 2 via the refrigerant pipe 6. The refrigerant flowed into
the relay unit 2 passes through the opening and closing device 24a, and is expanded
at the relay-side expansion device 23a or the relay-side expansion device 23b, thereby
changing into a low-temperature, low-pressure two-phase state. The two-phase refrigerant
flows into the heat medium heat exchanger 21a or the heat medium heat exchanger 21b
and, in the heat medium heat exchanger 21a or the heat medium heat exchanger 21b,
receives heat from the heat medium circulating in the heat medium circulation circuit
B, thereby changing into a low-temperature, low-pressure gaseous state. The gaseous
refrigerant flows out from the relay unit 2 via the relay-side refrigerant flow passage
switching device 25a or the relay-side refrigerant flow passage switching device 25b.
Then, the gaseous refrigerant flows into the outdoor unit 1 again via the refrigerant
pipe 6. The refrigerant flowed into the outdoor unit 1 passes through the first backflow
prevention device 18d and is sucked into the compressor 10 again via the refrigerant
flow passage switching device 11 and the accumulator 14.
[0079] In the heat medium circulation circuit B, the heat medium is cooled by the refrigerant
at both the heat medium heat exchanger 21a and the heat medium heat exchanger 21 b.
The cooled heat medium flows in the heat medium main pipe 5 and the heat medium branch
pipes 51 by means of the pump 22a and pump 22b. The heat medium, which has flowed
into the indoor heat exchanger 31a, 31b or 31c via the second heat medium flow passage
switching device 27a, 27b or 27c, receives heat from indoor air at the indoor heat
exchanger. The indoor air is thus cooled, and cooling of air-conditioned space is
performed. The refrigerant flowed out from the indoor heat exchanger 31a, 31b or 31c
flows into the heat medium flow control device 28a, 28b or 28c. Then, the refrigerant
passes through the first heat medium flow passage switching device 26a, 26b or 26c
and flows into the heat medium heat exchanger 21a or the heat medium heat exchanger
21b, and the refrigerant is cooled there and then is sucked into the pump 22a or the
pump 22b again. Note that when there is no heat load for the indoor heat exchanger
31a, 31b or 31c, the corresponding heat medium flow control device 28a, 28b or 28c
is completely closed. In addition, when heat load is present for the indoor heat exchanger
31a, 31b or 31c, the opening degree of the corresponding heat medium flow control
device 28a, 28b or 28c is adjusted so that the heat load in the indoor heat exchanger
31a, 31b or 31c is controlled.
<Cooling-main operation Mode>
[0080] In a cooling-main operation mode, the refrigerant in a high-temperature, high-pressure
gaseous state discharged from the compressor 10 flows into the heat-source-side heat
exchanger 12 via the refrigerant flow passage switching device 11. In the heat-source-side
heat exchanger 12, the refrigerant is condensed by rejecting heat to ambient air and
changes into a two-phase state, and flows out from the outdoor unit 1 via the first
backflow prevention device 18a. Then, the refrigerant flows into the relay unit 2
via the refrigerant pipe 6. The refrigerant flowed into the relay unit 2 passes through
the relay-side refrigerant flow passage switching device 25b and then flows into the
heat medium heat exchanger 21b, which functions as a condenser. In the heat medium
heat exchanger 21b, the refrigerant rejects heat to the heat medium circulating in
the heat medium circulation circuit B, thereby changing into a high-pressure liquid
state. The high-pressure liquid refrigerant is expanded at the relay-side expansion
device 23b and changes into a low-temperature, low-pressure two-phase state. The two-phase
refrigerant flows into the heat medium heat exchanger 21a, which functions as an evaporator,
via the relay-side expansion device 23a. In the heat medium heat exchanger 21a, the
refrigerant receives heat from the heat medium circulating in the heat medium circulation
circuit B, thereby changing into a low-pressure gaseous state, and then flows out
from the relay unit 2 via the relay-side refrigerant flow passage switching device
25a. Then, the refrigerant flows into the outdoor unit 1 again via the refrigerant
pipe 6. The refrigerant flowed in to the outdoor unit 1 passes through the first backflow
prevention device 18d and is sucked into the compressor 10 again via the refrigerant
flow passage switching device 11 and the accumulator 14.
[0081] In the heat medium circulation circuit B, heating energy of the refrigerant is transferred
to the head medium at the heat medium heat exchanger 21b. Then, the heated heat medium
flows in the heat medium main pipe 5 and the heat medium branch pipes 51 by means
of the pump 22b. By operating the first heat medium flow passage switching devices
26a to 26c and the second heat medium flow passage switching devices 27a to 27c, the
heat medium is caused to flow into the indoor heat exchangers 31a, 31b and/or 31c
to which a heating operation is requested, and rejects heat to the indoor air. The
indoor air is thus heated, and heating of air-conditioned space is performed. Meanwhile,
cooling energy of the refrigerant is transferred to the heat medium at the heat medium
heat exchanger 21a. Then, the cooled heat medium flows in the heat medium main pipe
5 and the heat medium branch pipes 51 by means of the pump 22a. By operating the first
heat medium flow passage switching devices 26a to 26c and the second heat medium flow
passage switching devices 27a to 27c, the heat medium is caused to flow into the indoor
heat exchangers 31a, 31b and/or 31c to which a cooling operation is requested, and
receives heat from the indoor air. The indoor air is thus cooled, and cooling of air-conditioned
space is performed. Note that when there is no heat load for the indoor heat exchanger
31a, 31b or 31c, the corresponding heat medium flow control device 28a, 28b or 28c
is completely closed. In addition, when heat load is present for the indoor heat exchanger
31a, 31b or 31c, the opening degree of the corresponding heat medium flow control
device 28a, 28b or 28c is adjusted so that the heat load in the indoor heat exchanger
31a, 31b or 31c is controlled.
<Heating-only operation Mode>
[0082] In a heating-only operation mode, the refrigerant in a high-temperature, high-pressure
gaseous state discharged from the compressor 10 passes through, via the refrigerant
flow passage switching device 11, the first connection pipe 16 and the first backflow
prevention device 18b and flows out from the outdoor unit 1. Then, the refrigerant
flows into the relay unit 2 via the refrigerant pipe 6. The refrigerant flowed into
the relay unit 2 passes through the relay-side refrigerant flow passage switching
device 25a or the relay-side refrigerant flow passage switching device 25b and flows
into the corresponding heat medium heat exchanger 21a or 21b. In the heat medium heat
exchanger 21a or 21b, the refrigerant rejects heat to the heat medium circulating
in the heat medium circulation circuit B, thereby changing into a high-pressure liquid
state. The high-pressure liquid refrigerant is expanded at the relay-side expansion
device 23a or the relay-side expansion device 23b, thereby changing into a low-temperature,
low-pressure two-phase state, and then passes through the opening and closing device
24b and flows out from the relay unit 2. Then, the refrigerant passes through the
refrigerant pipe 6 and flows into the outdoor unit 1 again. The refrigerant flowed
into the outdoor unit 1 passes through the second connection pipe 17 and the first
backflow prevention device 18c and flows into the heat-source-side heat exchanger
12, which functions as an evaporator. In the heat-source-side heat exchanger 12, the
refrigerant receives heat from ambient air, thereby changing into a low-temperature,
low-pressure gaseous state. The gaseous refrigerant is sucked into the compressor
10 again via the refrigerant flow passage switching device 11 and the accumulator
14. Note that the movement of the heat medium in the heat medium circulation circuit
B is the same as that in the cooling-only operation mode. In the heating-only operation
mode, the heat medium is heated by the refrigerant at the heat medium heat exchanger
21a or the heat medium heat exchanger 21b and rejects heat to the indoor air at the
indoor heat exchanger 31a or the indoor heat exchanger 31b, and heating of air-conditioned
space is thus performed.
<Heating-main operation Mode>
[0083] In a heating-main operation mode, the refrigerant in a high-temperature, high-pressure
gaseous state discharged from the compressor 10 passes through, via the refrigerant
flow passage switching device 11, the first connection pipe 16 and the first backflow
prevention device 18b and flows out from the outdoor unit 1. Then, the refrigerant
passes through the refrigerant pipe 6 and flows into the relay unit 2. The refrigerant
flowed into the relay unit 2 passes through the relay-side refrigerant flow passage
switching device 25b and flows into the heat medium heat exchanger 21b, which functions
as a condenser. In the heat medium heat exchanger 21b, the refrigerant rejects heat
to the heat medium circulating in the heat medium circulation circuit B, thereby changing
into a high-pressure liquid state. The high-pressure liquid refrigerant is expanded
at the relay-side expansion device 23b, thereby changing into a low-temperature, low-pressure
two-phase state. The two-phase refrigerant flows into the heat medium heat exchanger
21a, which functions as an evaporator, via the relay-side expansion device 23a. In
the heat medium heat exchanger 21a, the refrigerant receives heat from the heat medium
circulating in the heat medium circulation circuit B and flows out from the relay
unit 2 via the relay-side refrigerant flow passage switching device 25a. Then, the
refrigerant flows into the outdoor unit 1 again via the refrigerant pipe 6. The refrigerant
flowed into the outdoor unit 1 passes through the second connection pipe 17 and the
first backflow prevention device 18c, and flows into the heat-source-side heat exchanger
12, which functions as an evaporator. In the heat medium heat exchanger 21, the refrigerant
receives heat from ambient air, thereby changing into a low-temperature, low-pressure
gaseous state. The gaseous refrigerant is sucked into the compressor 10 again via
the refrigerant flow passage switching device 11 and the accumulator 14. Note that
the movement of the heat medium in the heat medium circulation circuit B and the operations
of the first heat medium flow passage switching devices 26a to 26c, the second heat
medium flow passage switching devices 27a to 27c, the heat medium flow control devices
28a to 28c, and the indoor heat exchangers 31a to 31c are the same as those in the
cooling-main operation mode.
[0084] Next, control of the air-conditioning apparatus 0 of Embodiment 2 will be described.
In the air-conditioning apparatus 0 of Embodiment 1, the heat medium heat exchanger
21 functions as an evaporator or a condenser, and either cooling or heating of the
heat medium is performed. Therefore, on the heat-source-side refrigerant circulation
circuit A side, either one of the evaporation temperature and the condensation temperature
in the heat medium heat exchanger 21 is controlled.
[0085] Here, in the air-conditioning apparatus 0 of Embodiment 2, in the cooling-only operation
mode, the heat medium heat exchanger 21a and the heat medium heat exchanger 21b function
as evaporators. In the heating-only operation mode, the heat medium heat exchanger
21a and the heat medium heat exchanger 21b function as condensers. Thus, the same
control as that in Embodiment 1 can be performed.
[0086] Meanwhile, in the cooling-main operation mode and the heating-main operation mode,
in the heat-source-side refrigerant circulation circuit A, the heat medium heat exchanger
21 that functions as an evaporator and the heat medium heat exchanger 21 that functions
as a condenser are present at the same time, as described above. At this time, it
is difficult to perform optimal control based on both a target temperature gradient
for cooling an indoor space and a target temperature gradient for heating an indoor
space. In the cooling-main operation mode, the heat load for cooling is large. Thus,
the control processing device 210 of the relay unit control device 200 sets a reference
temperature gradient among the target temperature gradients of the indoor units 3
operating under a cooling mode, and the control is performed by executing the processing
described in Embodiment 1. Meanwhile, in the heating-main operation mode, the heat
load for heating is large. Thus, the control processing device 210 sets a reference
temperature gradient among the target temperature gradients of the indoor units 3
operating under a heating mode, and the control is performed by executing the processing
described in Embodiment 1.
[0087] As described above, the control described in Embodiment 1 can be performed also in
the air-conditioning apparatus 0 of Embodiment 2 capable of performing cooling and
heating simultaneous operations. Therefore, according to the temperatures of indoor
spaces in which heat loads are present, supply of heat from the heat-source-side refrigerant
circulation circuit A side can be controlled and thus the temperatures of the heat
medium circulating in the heat medium circulation circuit B can be changed.
Embodiment 3
[0088] Fig. 7 is a diagram illustrating a configuration of an air-conditioning apparatus
0 according to Embodiment 3 of the present disclosure. In Fig. 7, the devices denoted
by the same reference symbols as those in Fig. 1 perform the same operations as those
of Embodiment 1. In the air-conditioning apparatus 0 of Embodiment 3, a plurality
of the relay units 2 described in Embodiment 1 or Embodiment 2 are connected to the
outdoor unit 1 in parallel by using the refrigerant pipe 6, to thereby form the heat-source-side
refrigerant circulation circuit A.
[0089] As described above, according to the air-conditioning apparatus 0 of Embodiment 3,
even in the air-conditioning apparatus 0 of Embodiment 3 in which a plurality of relay
units 2 are provided and connected to the outdoor unit 1 in parallel, communication
can be performed between units. Thus, the controls described in Embodiment 1 and Embodiment
2 can be performed.
Embodiment 4
[0090] Fig. 8 is a diagram illustrating a configuration of an air-conditioning apparatus
0 according to Embodiment 4 of the present disclosure. In Fig. 8, the devices denoted
by the same reference symbols as those in Fig. 2 perform the same operations as those
of Embodiment 1. In the air-conditioning apparatus 0 of Embodiment 4, the devices
of the relay unit 2 described in Embodiment 1 or Embodiment 2 are housed and integrated
in the outdoor unit 1. Thus, in the air-conditioning apparatus 0 of Embodiment 4,
the outdoor unit 1 and the indoor units 3 are connected by the heat medium main pipes
5 and the heat medium branch pipes 51. Because the outdoor unit 1 houses all the devices
of heat-source-side refrigerant circulation circuit A, the amount of the refrigerant
can be reduced. In addition, only connection of the outdoor unit 1 and the indoor
units 3 by pipes is required, piping work can be facilitated. Furthermore, without
providing the relay unit 2 independently, the controls described in Embodiment 1 and
Embodiment 2 can be performed.
Embodiment 5
[0091] Fig. 9 is a diagram illustrating a configuration of an air-conditioning apparatus
0 according to Embodiment 5 of the present disclosure. In Fig. 9, the devices denoted
by the same reference symbols as those in Fig. 2 perform the same operations as those
of Embodiment 1. As illustrated in Fig. 9, in the air-conditioning apparatus 0 of
Embodiment 5, a flow control unit 4 including a plurality of flow control devices
41 (flow control devices 41a to 41c) are installed, in place of the indoor flow control
devices 32 installed in the indoor units 3. The flow control unit 4 includes a flow
adjustment control device 400. The flow adjustment control device 400 can communicate
with controllers of other units. By providing the flow control unit 4 and consolidating
a plurality of flow control devices 41 in air-conditioning apparatus 0 of Embodiment
5, maintenance of the air-conditioning apparatus 0 can be facilitated. Because the
flow control unit 4 is configured to be capable of communicating signals containing
various data, the air-conditioning apparatus 0 capable of performing efficient operations
can be provided also in Embodiment 5.
Embodiment 6
[0092] In the embodiments described above, the relay unit control device 200 determines
whether or not to change the temperature of the heat medium based on a change in a
temperature difference of the suction temperature, which is the temperature of an
indoor space, however, the determination method is not limited thereto. The determination
for the temperature of the heat medium may be performed based on, for example, a relationship
between a target temperature gradient and a temperature difference of the suction
temperature. Furthermore, the determination of the temperature of the heat medium
may be performed based on a heat quantity.
Reference Signs List
[0093] 0 air-conditioning apparatus 1 outdoor unit 2 relay unit 3, 3a, 3b, 3c indoor unit
4 flow control unit 5 heat medium main pipe 6 refrigerant pipe 10 compressor 11 refrigerant
flow passage switching device 12 heat-source-side heat exchanger 13 expansion device
14 accumulator 15 heat-source-side fan 16 first connection pipe 17 second connection
pipe 18a, 18b, 18c, 18d first backflow prevention device 21, 21a, 21b heat medium
heat exchanger 22, 22a, 22b pump 23, 23a, 23b relay-side expansion device 24, 24a,
24b opening and closing device 25, 25a, 25b relay-side refrigerant flow passage switching
device 26, 26a, 26b, 26c first heat medium flow passage switching device 27, 27a,
27b, 27c second heat medium flow passage switching device 28, 28a, 28b, 28c heat medium
flow control device 31, 31 a, 31b, 31c indoor heat exchanger 32, 32a, 32b, 32c indoor
flow control device 33, 33a, 33b, 33c indoor-side fan 41, 41a, 41b, 41c flow control
device 51 heat medium branch pipe 100 outdoor unit control device 200 relay unit control
device 210 control processing device 211 temperature gradient setting processing unit
212 calculation processing unit 213 determination processing unit 214 heat-source-side
control processing unit 220 memory device 230 clocking device 240 communication device
300, 300a, 300b, 300c indoor unit control device 400 flow adjustment control device
501 discharge temperature sensor 502 discharge pressure sensor 503 outdoor temperature
sensor 504, 504a, 504b first refrigerant temperature sensor 505, 505a, 505b second
refrigerant temperature sensor 506, 506a, 506b heat-source-side refrigerant pressure
sensor 511, 511a, 511b heat medium inflow port side temperature sensor 512, 512a,
512b heat medium outflow port side temperature sensor 513, 513a, 513b, 513c indoor
inflow port side temperature sensor 514, 514a, 514b, 514c indoor outflow port side
temperature sensor 515, 515a, 515b, 515c indoor temperature sensor 521, 521a, 521b,
521c indoor inflow side pressure sensor 522, 522a, 522b, 522c indoor outflow side
pressure sensor