U.S. patent application number 12/304883 was filed with the patent office on 2009-04-23 for air conditioner.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. Invention is credited to Shinichi Kasahara, Tadafumi Nishimura, Takahiro Yamaguchi.
Application Number | 20090100849 12/304883 |
Document ID | / |
Family ID | 38845453 |
Filed Date | 2009-04-23 |
United States Patent
Application |
20090100849 |
Kind Code |
A1 |
Nishimura; Tadafumi ; et
al. |
April 23, 2009 |
AIR CONDITIONER
Abstract
An air conditioner includes a pipe volume calculating section
and a refrigerant circuit configured by the interconnection of a
heat source unit and a utilization unit via a refrigerant
communication pipe. The pipe volume calculating section calculates
the volume of the refrigerant communication pipe based on an
additional charging quantity which is a refrigerant quantity to be
additionally charged after the refrigerant circuit is configured by
interconnecting the heat source unit and the utilization unit via
the refrigerant communication pipe.
Inventors: |
Nishimura; Tadafumi; (Osaka,
JP) ; Kasahara; Shinichi; (Osaka, JP) ;
Yamaguchi; Takahiro; (Osaka, JP) |
Correspondence
Address: |
GLOBAL IP COUNSELORS, LLP
1233 20TH STREET, NW, SUITE 700
WASHINGTON
DC
20036-2680
US
|
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka-shi, Osaka
JP
|
Family ID: |
38845453 |
Appl. No.: |
12/304883 |
Filed: |
June 22, 2007 |
PCT Filed: |
June 22, 2007 |
PCT NO: |
PCT/JP2007/062589 |
371 Date: |
December 15, 2008 |
Current U.S.
Class: |
62/149 |
Current CPC
Class: |
F25B 2600/21 20130101;
F25B 2313/0233 20130101; F25B 2313/02741 20130101; F25B 49/005
20130101; F25B 45/00 20130101; F25B 2500/19 20130101; F25B 2500/01
20130101; F25B 2700/04 20130101; F25B 13/00 20130101 |
Class at
Publication: |
62/149 |
International
Class: |
F25B 45/00 20060101
F25B045/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 26, 2006 |
JP |
2006-175083 |
Claims
1. An air conditioner comprising: a refrigerant circuit including a
refrigerant communication pipe interconnecting a heat source unit
and a utilization unit; and a pipe volume calculating section
configured to calculate volume of the refrigerant communication
pipe based on an additional charging quantity, the additional
charging quantity being a refrigerant quantity additionally charged
after interconnecting the refrigerant communication pipe to the
heat source unit and the utilization unit.
2. The air conditioner according to claim 1, further comprising a
refrigerant quantity judging section configured to judge whether or
not refrigerant quantity charged in the refrigerant circuit has
reached a target charging quantity based on an operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit in an automatic refrigerant charging operation
in which refrigerant is additionally charged into the refrigerant
circuit, the additional charging quantity being the refrigerant
quantity additionally charged into the refrigerant circuit in the
automatic refrigerant charging operation.
3. An air conditioner comprising: a refrigerant circuit including a
refrigerant communication pipe interconnecting a heat source unit
and a utilization unit; and a pipe volume calculating section
configured to calculate volume of the refrigerant communication
pipe based on a communication pipe refrigerant quantity that is a
refrigerant quantity in the refrigerant communication pipe, the
communication pipe refrigerant quantity being determined by
subtracting an inside-unit refrigerant quantity from a total
charged refrigerant quantity, and the inside-unit refrigerant
quantity being a refrigerant quantity in the refrigerant circuit
excluding the refrigerant communication pipe, and the total charged
refrigerant quantity being a refrigerant quantity in the entire
refrigerant circuit after the refrigerant is additionally charged
thereinto.
4. The air conditioner according to claim 2, further comprising a
refrigerant quantity calculating means section configured to
calculate an inside-unit refrigerant quantity, the inside-unit
refrigerant quantity a refrigerant quantity in the refrigerant
circuit excluding the refrigerant pipe from an operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit in the automatic refrigerant charging
operation, the pipe volume calculating section being further
configured to determine a total charged refrigerant quantity, the
total charged refrigerant being a refrigerant quantity in the
entire refrigerant circuit immediately after the automatic
refrigerant charging operation by adding the additional charging
quantity to an initial charging quantity, and the initial charging
quantity being a refrigerant quantity charged in the refrigerant
circuit before the automatic refrigerant charging operation, the
pipe volume calculating section being further configured to
determine a communication pipe refrigerant quantity, the
communication pipe refrigerant quantity being a refrigerant
quantity in the refrigerant communication pipe determined by
subtracting the inside-unit refrigerant quantity from the total
charged refrigerant quantity, the pipe volume calculating section
being further configured to calculate a density of the refrigerant
flowing through the refrigerant communication pipe from the
operation state quantity of constituent equipment or refrigerant
flowing in the refrigerant circuit, and the pipe volume calculating
section being further configured to calculate the volume of the
refrigerant communication pipe based on the communication pipe
refrigerant quantity and the density.
5. The air conditioner according to claim 4, wherein the
refrigerant communication pipe includes a liquid refrigerant
communication pipe and a gas refrigerant communication pipe, the
pipe volume calculating section is further configured to calculate
a liquid refrigerant density and a gas refrigerant density, the
liquid refrigerant density is a density of liquid refrigerant
flowing through the liquid refrigerant communication pipe, and the
gas refrigerant density is a density of gas refrigerant flowing
through the gas refrigerant communication pipe, and the pipe volume
calculating section is further configured to calculate the volume
of the liquid refrigerant communication pipe and the volume of the
gas refrigerant communication pipe based on the communication pipe
refrigerant quantity, a volume ratio between the liquid refrigerant
communication pipe and the gas refrigerant communication pipe, the
liquid refrigerant density, and the gas refrigerant density.
6. The air conditioner according claim 5, wherein the refrigerant
quantity calculating means section is configured to calculate a
total calculated refrigerant quantity, the total calculated
refrigerant quantity being a refrigerant quantity in the entire
refrigerant circuit based on the volume of the refrigerant
communication pipe calculated by the pipe volume calculating
section and based on the operation state quantity of constituent
equipment or refrigerant flowing in the refrigerant circuit in a
refrigerant leak detection operation in which whether or not there
is a refrigerant leak from the refrigerant circuit is judged, and
the refrigerant quantity judging section is further configured to
judge whether or not there is a refrigerant leak from the
refrigerant circuit by comparing the total calculated refrigerant
quantity with a reference refrigerant quantity that serves as a
reference for judging whether or not there is a refrigerant leak
from the refrigerant circuit.
7. The air conditioner according to claim 2, wherein the pipe
volume calculating section is configured to calculate a density of
the refrigerant flowing through the refrigerant communication pipe
from the operation state quantity of constituent equipment or
refrigerant flowing in the refrigerant circuit, and the pipe volume
calculating section is further configured to calculate the volume
of the refrigerant communication pipe based on the additional
charging quantity and the density.
8. The air conditioner according to claim 7, wherein the
refrigerant communication pipe includes a liquid refrigerant
communication pipe and a gas refrigerant communication pipe, and
the pipe volume calculating section is configured to calculate a
liquid refrigerant density and a gas refrigerant density, the
liquid refrigerant density is a density of liquid refrigerant
flowing through the liquid refrigerant communication pipe, and the
gas refrigerant density is a density of gas refrigerant flowing
through the gas refrigerant communication pipe, and the pipe volume
calculating section is further configured to calculate the volume
of the liquid refrigerant communication pipe and the volume of the
gas refrigerant communication pipe based on the additional charging
quantity, a volume ratio between the liquid refrigerant
communication pipe and the gas refrigerant communication pipe, the
liquid refrigerant density, and the gas refrigerant density.
9. The air conditioner according to claim 8, further comprising a
refrigerant quantity calculating section configured to calculate a
total calculated refrigerant quantity, the total calculated
refrigerant quantity being a refrigerant quantity in the entire
refrigerant circuit based on the volume of the refrigerant
communication pipe calculated by the pipe volume calculating
section and based on the operation state quantity of constituent
equipment or refrigerant flowing in the refrigerant circuit in a
refrigerant leak detection operation in which whether or not there
is a refrigerant leak from the refrigerant circuit is judged, the
refrigerant quantity judging section being further configured to
judge whether or not there is a refrigerant leak from the
refrigerant circuit by comparing the total calculated refrigerant
quantity with a reference refrigerant quantity that serves as a
reference for judging whether or not there is a refrigerant leak
from the refrigerant circuit.
10. The air conditioner according to claim 7, further comprising a
refrigerant quantity calculating section configured to calculate a
total calculated refrigerant quantity, the total calculated
refrigerant quantity being a refrigerant quantity in the entire
refrigerant circuit based on the volume of the refrigerant
communication pipe calculated by the pipe volume calculating
section and based on the operation state quantity of constituent
equipment or refrigerant flowing in the refrigerant circuit in a
refrigerant leak detection operation in which whether or not there
is a refrigerant leak from the refrigerant circuit is judged, the
refrigerant quantity judging section being further configured to
judge whether or not there is a refrigerant leak from the
refrigerant circuit by comparing the total calculated refrigerant
quantity with a reference refrigerant quantity that serves as a
reference for judging whether or not there is a refrigerant leak
from the refrigerant circuit.
11. The air conditioner according claim 4, wherein the refrigerant
quantity calculating section is configured to calculate a total
calculated refrigerant quantity, the total calculated refrigerant
quantity being a refrigerant quantity in the entire refrigerant
circuit based on the volume of the refrigerant communication pipe
calculated by the pipe volume calculating section and based on the
operation state quantity of constituent equipment or refrigerant
flowing in the refrigerant circuit in a refrigerant leak detection
operation in which whether or not there is a refrigerant leak from
the refrigerant circuit is judged, and the refrigerant quantity
judging section is further configured to judge whether or not there
is a refrigerant leak from the refrigerant circuit by comparing the
total calculated refrigerant quantity with a reference refrigerant
quantity that serves as a reference for judging whether or not
there is a refrigerant leak from the refrigerant circuit.
Description
TECHNICAL FIELD
[0001] The present invention relates to a function to judge the
adequacy of the refrigerant quantity in a refrigerant circuit of an
air conditioner. More specifically, the present invention relates
to a function to judge the adequacy of the refrigerant quantity in
a refrigerant circuit of an air conditioner configured by the
interconnection of a heat source unit and a utilization unit via a
refrigerant communication pipe.
BACKGROUND ART
[0002] Conventionally, in a separate type air conditioner
configured by the interconnection of a heat source unit and a
utilization unit via a refrigerant communication pipe, information
on the length and the like of the refrigerant communication pipe is
input in order to accurately judge the excess or deficiency of the
refrigerant quantity in a refrigerant circuit (for example, see
Patent Document 1).
[0003] <Patent Document 1>
[0004] JP-A Publication No. H8-200905
DISCLOSURE OF THE INVENTION
[0005] However, the above described work to input information on
the refrigerant communication pipe is extremely laborious work. In
addition, there is a problem that an input error easily occurs.
[0006] An object of the present invention is to minimize the labor
of inputting information on a refrigerant communication pipe before
operating a separate type air conditioner, and at the same time, to
enable a highly accurate judgment of the adequacy of the
refrigerant quantity in a refrigerant circuit.
[0007] An air conditioner according to a first aspect of the
present invention includes a refrigerant circuit configured by the
interconnection of a heat source unit and a utilization unit via a
refrigerant communication pipe, and a pipe volume calculating
means. The pipe volume calculating means calculates the volume of
the refrigerant communication pipe based on an additional charging
quantity that is a refrigerant quantity to be additionally charged
after the refrigerant circuit is configured by the interconnection
of the heat source unit and the utilization unit via the
refrigerant communication pipe.
[0008] In this air conditioner, the volume of the refrigerant
communication pipe is calculated based on the additional charging
quantity that is the refrigerant quantity to be additionally
charged after the refrigerant circuit is configured by the
interconnection of the heat source unit and the utilization unit
via the refrigerant communication pipe. Thus, even when the volume
of the refrigerant communication pipe is unknown, it is possible to
calculate the volume of the refrigerant communication pipe by
inputting a value of the additional charging quantity. Accordingly,
it is possible to determine the volume of the refrigerant
communication pipe while minimizing the labor of inputting
information on the refrigerant communication pipe. As a result, it
is possible to judge the adequacy of the refrigerant quantity in
the refrigerant circuit with high accuracy.
[0009] An air conditioner according to a second aspect of the
present invention is the air conditioner according to the first
aspect of the present invention, further including a refrigerant
quantity judging means to judge whether or not the refrigerant
quantity charged in the refrigerant circuit has reached a target
charging quantity based on an operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit in an automatic refrigerant charging operation in which the
refrigerant is additionally charged into the refrigerant circuit.
The additional charging quantity is the refrigerant quantity
additionally charged into the refrigerant circuit in the automatic
refrigerant charging operation.
[0010] In this air conditioner, whether or not the target charging
quantity is reached can be judged based on the operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit, so that it is possible to reliably perform
additional refrigerant charging, and at the same time, it is
possible to determine a value of the additional charging quantity
required for the calculation of the volume of the refrigerant
communication pipe by performing the automatic refrigerant charging
operation.
[0011] An air conditioner according to a third aspect of the
present invention includes a refrigerant circuit configured by the
interconnection of a heat source unit and a utilization unit via a
refrigerant communication pipe, and a pipe volume calculating
means. The pipe volume calculating means calculates the volume of
the refrigerant communication pipe based on a communication pipe
refrigerant quantity that is a refrigerant quantity in the
refrigerant communication pipe. The communication pipe refrigerant
quantity is determined by subtracting an inside-unit refrigerant
quantity that is a refrigerant quantity in the refrigerant circuit
excluding the refrigerant communication pipe from a total charged
refrigerant quantity that is a refrigerant quantity in the entire
refrigerant circuit after the refrigerant is additionally charged
thereinto.
[0012] In this air conditioner, the volume of the refrigerant
communication pipe is calculated based on the communication pipe
refrigerant quantity that is the refrigerant quantity in the
refrigerant communication pipe. The communication pipe refrigerant
quantity is determined by subtracting the inside-unit refrigerant
quantity that is the refrigerant quantity in the refrigerant
circuit excluding the refrigerant communication pipe from the total
charged refrigerant quantity that is the refrigerant quantity in
the entire refrigerant circuit after the refrigerant is
additionally charged thereinto. Thus, even when the volume of the
refrigerant communication pipe is unknown, it is possible to
calculate the volume of the refrigerant communication pipe by
inputting a value of the additional charging quantity. Accordingly,
it is possible to determine the volume of the refrigerant
communication pipe while minimizing the labor of inputting
information on the refrigerant communication pipe. As a result, it
is possible to judge the adequacy of the refrigerant quantity in
the refrigerant circuit with high accuracy.
[0013] An air conditioner according to a fourth aspect of the
present invention is the air conditioner according to the second
aspect of the present invention, further including a refrigerant
quantity calculating means to calculate an inside-unit refrigerant
quantity that is a refrigerant quantity in the refrigerant circuit
excluding the refrigerant pipe from the operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit in the automatic refrigerant charging operation. The pipe
volume calculating means determines a total charged refrigerant
quantity that is a refrigerant quantity in the entire refrigerant
circuit immediately after the automatic refrigerant charging
operation, by adding the additional charging quantity to an initial
charging quantity that is a refrigerant quantity charged in the
refrigerant circuit before the automatic refrigerant charging
operation. Then, the pipe volume calculating means determines a
communication pipe refrigerant quantity that is a refrigerant
quantity in the refrigerant communication pipe by subtracting the
inside-unit refrigerant quantity from the total charged refrigerant
quantity, and calculates a density of the refrigerant flowing
through the refrigerant communication pipe from the operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit. Then, the pipe volume calculating means
calculates the volume of the refrigerant communication pipe based
on the communication pipe refrigerant quantity and the density.
[0014] In this air conditioner, it is possible to calculate the
communication pipe refrigerant quantity present with high accuracy
during the automatic refrigerant charging operation by subtracting
the inside-unit refrigerant quantity calculated based on the
operation state quantity of constituent equipment or refrigerant
flowing in the refrigerant circuit in the automatic refrigerant
charging operation, from the total charged refrigerant quantity
determined by adding the additional charging quantity to the
initial charging quantity. Thus, the volume of the refrigerant
communication pipe can be calculated with high accuracy.
[0015] An air conditioner according to a fifth aspect of the
present invention is the air conditioner according to the fourth
aspect of the present invention, wherein the refrigerant
communication pipe includes a liquid refrigerant communication pipe
and a gas refrigerant communication pipe. The pipe volume
calculating means calculates a liquid refrigerant density that is a
density of liquid refrigerant flowing through the liquid
refrigerant communication pipe and a gas density that is a density
of gas refrigerant flowing through the gas refrigerant
communication pipe. Then, the pipe volume calculating means
calculates the volume of the liquid refrigerant communication pipe
and the volume of the gas refrigerant communication pipe based on
the communication pipe refrigerant quantity, a volume ratio between
the liquid refrigerant communication pipe and the gas refrigerant
communication pipe, the liquid refrigerant density, and the gas
refrigerant density.
[0016] The liquid refrigerant communication pipe and the gas
refrigerant communication pipe are provided so as to interconnect
the utilization unit and the heat source unit, so that these pipes
have substantially the same pipe length but different pipe
diameters, i.e., different flow passage cross-sectional areas, due
to the different densities of the refrigerant flowing through the
pipes. Therefore, the volume ratio between the liquid refrigerant
communication pipe and the gas refrigerant communication pipe will
substantially correspond to a flow passage cross-sectional area
ratio between these pipes, and furthermore, this volume ratio will
be within a certain range because the flow passage cross-sectional
area ratio is predetermined based on the capacities and models of
the utilization unit and the heat source unit. Further, if the
volume ratio between the liquid refrigerant communication pipe and
the gas refrigerant communication pipe is known, it will be
possible to calculate both the volume of the liquid refrigerant
communication pipe and the volume of the gas refrigerant
communication pipe, because a total value obtained by adding a
value of the multiplication between the volume of the liquid
refrigerant communication pipe and the liquid refrigerant density
to a value of the multiplication between the volume of the gas
refrigerant communication pipe and the gas refrigerant density will
be equal to the communication pipe refrigerant quantity.
[0017] Consequently, in this air conditioner, it is possible to
easily calculate both the volume of the liquid refrigerant
communication pipe and the volume of the gas refrigerant
communication pipe by predetermining the volume ratio between the
liquid refrigerant communication pipe and the gas refrigerant
communication pipe.
[0018] An air conditioner according to a sixth aspect of the
present invention is the air conditioner according to the fourth or
fifth aspect of the present invention, wherein the refrigerant
quantity calculating means calculates a total calculated
refrigerant quantity that is a refrigerant quantity in the entire
refrigerant circuit based on the volume of the refrigerant
communication pipe calculated by the pipe volume calculating means
and based on the operation state quantity of constituent equipment
or refrigerant flowing in the refrigerant circuit in a refrigerant
leak detection operation in which whether or not there is a
refrigerant leak from the refrigerant circuit is judged. The
refrigerant quantity judging means judges whether or not there is a
refrigerant leak from the refrigerant circuit by comparing the
total calculated refrigerant quantity with a reference refrigerant
quantity that serves as a reference for judging whether or not
there is a refrigerant leak from the refrigerant circuit.
[0019] In this air conditioner, the pipe volume calculating means
can calculate the volume of the refrigerant communication pipe, so
that even if the volume of the refrigerant communication pipe is
unknown, it is possible to calculate the refrigerant quantity in
the refrigerant circuit in the refrigerant leak detection operation
using the volume of the refrigerant communication pipe calculated
by the pipe volume calculating means. Accordingly, it is possible
to determine, with high accuracy, whether or not there is a
refrigerant leak from the refrigerant circuit while minimizing the
labor of inputting information on the refrigerant communication
pipe.
[0020] An air conditioner according to a seventh aspect of the
present invention is the air conditioner according to the second
aspect of the present invention, wherein the pipe volume
calculating means calculates a density of the refrigerant flowing
through the refrigerant communication pipe from the operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit, and calculates the volume of the refrigerant
communication pipe based on the additional charging quantity and
the density.
[0021] In this air conditioner, for example, the refrigerant whose
quantity is substantially equal to an inside-unit refrigerant
quantity that is a refrigerant quantity in the refrigerant circuit
excluding the refrigerant communication pipe and that is present
when the refrigerant quantity in the refrigerant circuit is reached
the target charging quantity by the automatic refrigerant charging
operation, is charged as an initial charging quantity into the
refrigerant circuit before the automatic refrigerant charging
operation is performed, and thereby the refrigerant quantity to be
additionally charged into the refrigerant circuit in the automatic
refrigerant charging operation can be regarded as a refrigerant
quantity corresponding to the refrigerant quantity present in the
refrigerant communication pipe. Accordingly, it is possible to
calculate the volume of the refrigerant communication pipe with
high accuracy based on the additional charging quantity and the
density.
[0022] An air conditioner according to an eighth aspect of the
present invention is the air conditioner according to the seventh
aspect of the present invention, wherein the refrigerant
communication pipe includes a liquid refrigerant communication pipe
and a gas refrigerant communication pipe. The pipe volume
calculating means calculates a liquid refrigerant density that is a
density of liquid refrigerant flowing through the liquid
refrigerant communication pipe and a gas refrigerant density that
is a density of gas refrigerant flowing through the gas refrigerant
communication pipe. Then, the pipe volume calculating means
calculates the volume of the liquid refrigerant communication pipe
and the volume of the gas refrigerant communication pipe based on
the additional charging quantity, a volume ratio between the liquid
refrigerant communication pipe and the gas refrigerant
communication pipe, the liquid refrigerant density, and the gas
refrigerant density.
[0023] The liquid refrigerant communication pipe and the gas
refrigerant communication pipe are provided so as to interconnect
the utilization unit and the heat source unit, so that these pipes
have substantially the same pipe length but different pipe
diameters, i.e., different flow passage cross-sectional areas, due
to the different densities of the refrigerant flowing through the
pipes. Therefore, the volume ratio between the liquid refrigerant
communication pipe and the gas refrigerant communication pipe
substantially corresponds to a flow passage cross-sectional area
ratio between these pipes, and further more, this volume ratio will
be within a certain range because the flow passage cross-sectional
area ratio is predetermined based on the capacities and models of
the utilization unit and the heat source unit. Further, if the
volume ratio between the liquid refrigerant communication pipe and
the gas refrigerant communication pipe is known, it will be
possible to calculate both the volume of the liquid refrigerant
communication pipe and the volume of the gas refrigerant
communication pipe because a total value obtained by adding a value
of the multiplication between the volume of the liquid refrigerant
communication pipe and the liquid refrigerant density to a value of
the multiplication between the volume of the gas refrigerant
communication pipe and the gas refrigerant density will be equal to
the additional charging quantity.
[0024] Consequently, in this air conditioner, it is possible to
easily calculate both the volume of the liquid refrigerant
communication pipe and the volume of the gas refrigerant
communication pipe by predetermining the volume ratio between the
liquid refrigerant communication pipe and the gas refrigerant
communication pipe.
[0025] An air conditioner according to a ninth aspect of the
present invention is the air conditioner according to the seventh
or eighth aspect of the present invention, further including a
refrigerant quantity calculating means to calculate a total
calculated refrigerant quantity that is a refrigerant quantity in
the entire refrigerant circuit based on the volume of the
refrigerant communication pipe calculated by the pipe volume
calculating means and based on the operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit in a refrigerant leak detection operation in which whether
or not there is a refrigerant leak from the refrigerant circuit is
judged. The refrigerant quantity judging means judges whether or
not there is a refrigerant leak from the refrigerant circuit by
comparing the total calculated refrigerant quantity with a
reference refrigerant quantity that serves as a reference for
judging whether or not there is a refrigerant leak from the
refrigerant circuit.
[0026] In this air conditioner, the pipe volume calculating means
can calculate the volume of the refrigerant communication pipe, so
that even when the volume of the refrigerant communication pipe is
unknown, it is possible to calculate the refrigerant quantity in
the refrigerant circuit in the refrigerant leak detection operation
using the volume of the refrigerant communication pipe calculated
by the pipe volume calculating means. Accordingly, it is possible
to determine, with high accuracy, whether or not there is a
refrigerant leak from the refrigerant circuit while minimizing the
labor of inputting information on the refrigerant communication
pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic configuration view of an air
conditioner according to an embodiment of the present
invention.
[0028] FIG. 2 is a control block diagram of the air
conditioner.
[0029] FIG. 3 is a flowchart of a test operation mode.
[0030] FIG. 4 is a flowchart of an automatic refrigerant charging
operation.
[0031] FIG. 5 is a schematic diagram to show a state of refrigerant
flowing in a refrigerant circuit in a refrigerant quantity judging
operation (illustrations of a four-way switching valve and the like
are omitted).
[0032] FIG. 6 is a flowchart of a pipe volume calculation
process.
[0033] FIG. 7 is a flowchart of a refrigerant leak detection
operation mode.
DESCRIPTION OF THE REFERENCE SYMBOLS
[0034] 1 Air conditioner [0035] 2 Outdoor unit (heat source unit)
[0036] 4, 5 Indoor unit (utilization unit) [0037] 6 Liquid
refrigerant communication pipe (refrigerant communication pipe)
[0038] 7 Gas refrigerant communication pipe (refrigerant
communication pipe) [0039] 10 Refrigerant circuit
BEST MODE FOR CARRYING OUT THE INVENTION
[0040] In the following, an embodiment of an air conditioner
according to the present invention is described based on the
drawings.
(1) Configuration of the Air Conditioner
[0041] FIG. 1 is a schematic configuration view of an air
conditioner 1 according to an embodiment of the present invention.
The air conditioner 1 is a device that is used to cool and heat a
room in a building and the like by performing a vapor
compression-type refrigeration cycle operation. The air conditioner
1 mainly includes one outdoor unit 2 as a heat source unit, indoor
units 4 and 5 as a plurality (two in the present embodiment) of
utilization units connected in parallel thereto, and a liquid
refrigerant communication pipe 6 and a gas refrigerant
communication pipe 7 as refrigerant communication pipes which
interconnect the outdoor unit 2 and the indoor units 4 and 5. In
other words, the vapor compression-type refrigerant circuit 10 of
the air conditioner 1 in the present embodiment is configured by
the interconnection of the outdoor unit 2, the indoor units 4 and
5, and the liquid refrigerant communication pipe 6 and the gas
refrigerant communication pipe 7.
<Indoor Unit>
[0042] The indoor units 4 and 5 are installed by being embedded in
or hung from a ceiling of a room in a building and the like or by
being mounted or the like on a wall surface of a room. The indoor
units 4 and 5 are connected to the outdoor unit 2 via the liquid
refrigerant communication pipe 6 and the gas refrigerant
communication pipe 7, and configure a part of the refrigerant
circuit 10.
[0043] Next, the configurations of the indoor units 4 and 5 are
described. Note that, because the indoor units 4 and 5 have the
same configuration, only the configuration of the indoor unit 4 is
described here, and in regard to the configuration of the indoor
unit 5, reference numerals in the 50s are used instead of reference
numerals in the 40s representing the respective portions of the
indoor unit 4, and descriptions of those respective portions are
omitted.
[0044] The indoor unit 4 mainly includes an indoor side refrigerant
circuit 10a (an indoor side refrigerant circuit 10b in the case of
the indoor unit 5) that configures a part of the refrigerant
circuit 10. The indoor side refrigerant circuit 10a mainly includes
an indoor expansion valve 41 as an expansion mechanism and an
indoor heat exchanger 42 as a utilization side heat exchanger.
[0045] In the present embodiment, the indoor expansion valve 41 is
an electrically powered expansion valve connected to a liquid side
of the indoor heat exchanger 42 in order to adjust the flow rate or
the like of the refrigerant flowing in the indoor side refrigerant
circuit 10a.
[0046] In the present embodiment, the indoor heat exchanger 42 is a
cross fin-type fin-and-tube type heat exchanger configured by a
heat transfer tube and numerous fins, and is a heat exchanger that
functions as an evaporator for the refrigerant during a cooling
operation to cool the room air and functions as a condenser for the
refrigerant during a heating operation to heat the room air.
[0047] In the present embodiment, the indoor unit 4 includes an
indoor fan 43 as a ventilation fan for taking in room air into the
unit, causing the air to heat exchange with the refrigerant in the
indoor heat exchanger 42, and then supplying the air to the room as
supply air. The indoor fan 43 is a fan capable of varying an air
flow rate Wr of the air which is supplied to the indoor heat
exchanger 42, and in the present embodiment, is a centrifugal fan,
multi-blade fan, or the like, which is driven by a motor 43a
comprising a DC fan motor.
[0048] In addition, various types of sensors are disposed in the
indoor unit 4. A liquid side temperature sensor 44 that detects the
temperature of the refrigerant (i.e., the refrigerant temperature
corresponding to a condensation temperature Tc during the heating
operation or an evaporation temperature Te during the cooling
operation) is disposed at the liquid side of the indoor heat
exchanger 42. A gas side temperature sensor 45 that detects a
temperature Teo of the refrigerant is disposed at a gas side of the
indoor heat exchanger 42. A room temperature sensor 46 that detects
the temperature of the room air that flows into the unit (i.e., a
room temperature Tr) is disposed at a room air intake side of the
indoor unit 4. In the present embodiment, the liquid side
temperature sensor 44, the gas side temperature sensor 45, and the
room temperature sensor 46 comprise thermistors. In addition, the
indoor unit 4 includes an indoor side controller 47 that controls
the operation of each portion constituting the indoor unit 4.
Additionally, the indoor side controller 47 includes a
microcomputer and a memory and the like disposed in order to
control the indoor unit 4, and is configured such that it can
exchange control signals and the like with a remote controller (not
shown) for individually operating the indoor unit 4 and can
exchange control signals and the like with the outdoor unit 2 via a
transmission line 8a.
<Outdoor Unit>
[0049] The outdoor unit 2 is installed outside of a building and
the like, is connected to the indoor units 4 and 5 via the liquid
refrigerant communication pipe 6 and the gas refrigerant
communication pipe 7, and configures the refrigerant circuit 10
with the indoor units 4 and 5.
[0050] Next, the configuration of the outdoor unit 2 is described.
The outdoor unit 2 mainly includes an outdoor side refrigerant
circuit 10c that configures a part of the refrigerant circuit 10.
This outdoor side refrigerant circuit 10c mainly includes a
compressor, a four-way switching valve 22, an outdoor heat
exchanger 23 as a heat source side heat exchanger, an outdoor
expansion valve 38 as an expansion mechanism, an accumulator 24, a
subcooler 25 as a temperature adjustment mechanism, a liquid side
stop valve 26, and a gas side stop valve 27.
[0051] The compressor 21 is a compressor whose operation capacity
can be varied, and in the present embodiment, is a positive
displacement-type compressor driven by a motor 21a whose rotation
frequency Rm is controlled by an inverter. In the present
embodiment, only one compressor 21 is provided, but it is not
limited thereto, and two or more compressors may be connected in
parallel according to the number of connected units of indoor units
and the like.
[0052] The four-way switching valve 22 is a valve for switching the
direction of the flow of the refrigerant such that, during the
cooling operation, the four-way switching valve 22 is capable of
connecting a discharge side of the compressor 21 and a gas side of
the outdoor heat exchanger 23 and connecting a suction side of the
compressor 21 (specifically, the accumulator 24) and the gas
refrigerant communication pipe 7 (see the solid lines of the
four-way switching valve 22 in FIG. 1) to cause the outdoor heat
exchanger 23 to function as a condenser for the refrigerant
compressed in the compressor 21 and to cause the indoor heat
exchangers 42 and 52 to function as evaporators for the refrigerant
condensed in the outdoor heat exchanger 23; and such that, during
the heating operation, the four-way switching valve 22 is capable
of connecting the discharge side of the compressor 21 and the gas
refrigerant communication pipe 7 and connecting the suction side of
the compressor 21 and the gas side of the outdoor heat exchanger 23
(see the dotted lines of the four-way switching valve 22 in FIG. 1)
to cause the indoor heat exchangers 42 and 52 to function as
condensers for the refrigerant compressed in the compressor 21 and
to cause the outdoor heat exchanger 23 to function as an evaporator
for the refrigerant condensed in the indoor heat exchangers 42 and
52.
[0053] In the present embodiment, the outdoor heat exchanger 23 is
a cross-fin type fin-and-tube type heat exchanger configured by a
heat transfer tube and numerous fins, and is a heat exchanger that
functions as a condenser for the refrigerant during the cooling
operation and as an evaporator for the refrigerant during the
heating operation. The gas side of the outdoor heat exchanger 23 is
connected to the four-way switching valve 22, and the liquid side
thereof is connected to the liquid refrigerant communication pipe
6.
[0054] In the present embodiment, the outdoor expansion valve 38 is
an electrically powered expansion valve connected to a liquid side
of the outdoor heat exchanger 23 in order to adjust the pressure,
flow rate, or the like of the refrigerant flowing in the outdoor
side refrigerant circuit 10c.
[0055] In the present embodiment, the outdoor unit 2 includes an
outdoor fan 28 as a ventilation fan for taking in outdoor air into
the unit, causing the air to exchange heat with the refrigerant in
the outdoor heat exchanger 23, and then exhausting the air to the
outside. The outdoor fan 28 is a fan capable of varying an air flow
rate Wo of the air which is supplied to the outdoor heat exchanger
23, and in the present embodiment, is a propeller fan or the like
driven by a motor 28a comprising a DC fan motor.
[0056] The accumulator 24 is connected between the four-way
switching valve 22 and the compressor 21, and is a container
capable of accumulating excess refrigerant generated in the
refrigerant circuit 10 in accordance with the change in the
operation load of the indoor units 4 and 5 and the like.
[0057] In the present embodiment, the subcooler 25 is a double tube
heat exchanger, and is disposed to cool the refrigerant sent to the
indoor expansion valves 41 and 51 after the refrigerant is
condensed in the outdoor heat exchanger 23. In the present
embodiment, the subcooler 25 is connected between the outdoor
expansion valve 38 and the liquid side stop valve 26.
[0058] In the present embodiment, a bypass refrigerant circuit 61
as a cooling source of the subcooler 25 is disposed. Note that, in
the description below, a portion corresponding to the refrigerant
circuit 10 excluding the bypass refrigerant circuit 61 is referred
to as a main refrigerant circuit for convenience sake.
[0059] The bypass refrigerant circuit 61 is connected to the main
refrigerant circuit so as to cause a portion of the refrigerant
sent from the outdoor heat exchanger 23 to the indoor expansion
valves 41 and 51 to branch from the main refrigerant circuit and
return to the suction side of the compressor 21. Specifically, the
bypass refrigerant circuit 61 includes a branch circuit 61a
connected so as to branch a portion of the refrigerant sent from
the outdoor expansion valve 38 to the indoor expansion valves 41
and 51 at a position between the outdoor heat exchanger 23 and the
subcooler 25, and a merging circuit 61b connected to the suction
side of the compressor 21 so as to return a portion of refrigerant
from an outlet on a bypass refrigerant circuit side of the
subcooler 25 to the suction side of the compressor 21. Further, the
branch circuit 61a is disposed with a bypass expansion valve 62 for
adjusting the flow rate of the refrigerant flowing in the bypass
refrigerant circuit 61. Here, the bypass expansion valve 62
comprises an electrically operated expansion valve. In this way,
the refrigerant sent from the outdoor heat exchanger 23 to the
indoor expansion valves 41 and 51 is cooled in the subcooler 25 by
the refrigerant flowing in the bypass refrigerant circuit 61 which
has been depressurized by the bypass expansion valve 62. In other
words, performance of the subcooler 25 is controlled by adjusting
the opening degree of the bypass expansion valve 62.
[0060] The liquid side stop valve 26 and the gas side stop valve 27
are valves disposed at ports connected to external equipment and
pipes (specifically, the liquid refrigerant communication pipe 6
and the gas refrigerant communication pipe 7). The liquid side stop
valve 26 is connected to the outdoor heat exchanger 23. The gas
side stop valve 27 is connected to the four-way switching valve
22.
[0061] In addition, various sensors are disposed in the outdoor
unit 2. Specifically, disposed in the outdoor unit 2 are an suction
pressure sensor 29 that detects a suction pressure Ps of the
compressor 21, a discharge pressure sensor 30 that detects a
discharge pressure Pd of the compressor 21, a suction temperature
sensor 31 that detects a suction temperature Ts of the compressor
21, and a discharge temperature sensor 32 that detects a discharge
temperature Td of the compressor 21. The suction temperature sensor
31 is disposed at a position between the accumulator 24 and the
compressor 21. A heat exchanger temperature sensor 33 that detects
the temperature of the refrigerant flowing through the outdoor heat
exchanger 23 (i.e., the refrigerant temperature corresponding to
the condensation temperature Tc during the cooling operation or the
evaporation temperature Te during the heating operation) is
disposed in the outdoor heat exchanger 23. A liquid side
temperature sensor 34 that detects a refrigerant temperature Tco is
disposed at the liquid side of the outdoor heat exchanger 23. A
liquid pipe temperature sensor 35 that detects the temperature of
the refrigerant (i.e., a liquid pipe temperature T1p) is disposed
at the outlet on the main refrigerant circuit side of the subcooler
25. The merging circuit 61b of the bypass refrigerant circuit 61 is
disposed with a bypass temperature sensor 63 for detecting the
temperature of the refrigerant flowing through the outlet on the
bypass refrigerant circuit side of the subcooler 25. An outdoor
temperature sensor 36 that detects the temperature of the outdoor
air that flows into the unit (i.e., an outdoor temperature Ta) is
disposed at an outdoor air intake side of the outdoor unit 2. In
the present embodiment, the suction temperature sensor 31, the
discharge temperature sensor 32, the heat exchanger temperature
sensor 33, the liquid side temperature sensor 34, the liquid pipe
temperature sensor 35, the outdoor temperature sensor 36, and the
bypass temperature sensor 63 comprise thermistors. In addition, the
outdoor unit 2 includes an outdoor side controller 37 that controls
the operation of each portion constituting the outdoor unit 2.
Additionally, the outdoor side controller 37 includes a
microcomputer and a memory disposed in order to control the outdoor
unit 2, an inverter circuit that controls the motor 21a, and the
like, and is configured such that it can exchange control signals
and the like with the indoor side controllers 47 and 57 of the
indoor units 4 and 5 via the transmission line 8a. In other words,
a controller 8 that performs the operation control of the entire
air conditioner 1 is configured by the indoor side controllers 47
and 57, the outdoor side controller 37, and the transmission line
8a that interconnects the controllers 37, 47, and 57.
[0062] As shown in FIG. 2, the controller 8 is connected so as to
be able to receive detection signals of sensors 29 to 36, 44 to 46,
54 to 56, and 63 and also to be able to control various equipment
and valves 21, 22, 24, 28a, 38, 41, 43a, 51, 53a, and 62 based on
these detection signals and the like. In addition, the controller 8
is provided with an input unit 9a such that a set value for each
type of control can be input and changed and such that the total
charged refrigerant quantity including the refrigerant quantity
additionally charged into the refrigerant circuit 10 in an
automatic refrigerant charging operation (described later) and an
initial charging quantity can be input. In addition, a display 9b
comprising LEDs and the like is connected to the controller 8. The
display 9b is configured to indicate that additional charging is
completed in the automatic refrigerant charging operation
(described later) and that a refrigerant leak is detected in a
refrigerant leak detection operation (described later). Here, FIG.
2 is a control block diagram of the air conditioner 1. Note that
the input unit 9a is not limited to the one provided to the
controller 8, but may be the one that is connected to the
controller 8 as needed when inputting the additional charging
quantity and the total charged refrigerant quantity.
<Refrigerant Communication Pipe>
[0063] The refrigerant communication pipes 6 and 7 are refrigerant
pipes that are arranged on site when installing the air conditioner
1 at an installation site such as a building. As the refrigerant
communication pipes 6 and 7, pipes having various lengths and
diameters are used according to the installation conditions such as
an installation site, combination of an outdoor unit and an indoor
unit, and the like. Accordingly, for example, when installing a new
air conditioner, in order to calculate the additional charging
quantity of the refrigerant, it is necessary to obtain accurate
information regarding the lengths, diameters and the like of the
refrigerant communication pipes 6 and 7. However, such information
management and the calculation itself of the refrigerant quantity
are difficult. In addition, when utilizing an existing pipe to
renew an indoor unit and an outdoor unit, information regarding the
lengths, diameters and the like of the refrigerant communication
pipes 6 and 7 may have been lost in some cases.
[0064] As described above, the refrigerant circuit 10 of the air
conditioner 1 is configured by the interconnection of the indoor
side refrigerant circuits 10a and 10b, the outdoor side refrigerant
circuit 10c, and the refrigerant communication pipes 6 and 7. In
addition, it can also be that this refrigerant circuit 10 is
configured by the bypass refrigerant circuit 61 and the main
refrigerant circuit excluding the bypass refrigerant circuit 61.
Additionally, the controller 8 constituted by the indoor side
controllers 47 and 57 and the outdoor side controller 37 allows the
air conditioner 1 in the present embodiment to switch and operate
between the cooling operation and the heating operation by the
four-way switching valve 22 and to control each equipment of the
outdoor unit 2 and the indoor units 4 and 5 according to the
operation load of each of the indoor units 4 and 5.
(2) Operation of the Air Conditioner
[0065] Next, the operation of the air conditioner 1 in the present
embodiment is described.
[0066] The operation modes of the air conditioner 1 in the present
embodiment include: a normal operation mode where control of
constituent equipment of the outdoor unit 2 and the indoor units 4
and 5 is performed according to the operation load of each of the
indoor units 4 and 5; a test operation mode where a test operation
is performed after installation of constituent equipment of the air
conditioner 1 is performed (specifically, it is not limited to
after the first installation of equipment: it also includes, for
example, after modification by adding or removing constituent
equipment such as an indoor unit, after repair of damaged
equipment); and a refrigerant leak detection operation mode where,
after the test operation is finished and the normal operation has
started, whether or not there is a refrigerant leak from the
refrigerant circuit 10 is judged. The normal operation mode mainly
includes the cooling operation for cooling the room and the heating
operation for heating the room. In addition, the test operation
mode mainly includes the automatic refrigerant charging operation
to charge refrigerant into the refrigerant circuit 10, and a pipe
volume calculation process to calculate the volumes of the
refrigerant communication pipes 6 and 7.
[0067] Operation in each operation mode of the air conditioner 1 is
described below.
<Normal Operation Mode>
(Cooling Operation)
[0068] First, the cooling operation in the normal operation mode is
described with reference to FIGS. 1 and 2.
[0069] During the cooling operation, the four-way switching valve
22 is in the state represented by the solid lines in FIG. 1, i.e.,
a state where the discharge side of the compressor 21 is connected
to the gas side of the outdoor heat exchanger 23 and also the
suction side of the compressor 21 is connected to the gas sides of
the indoor heat exchangers 42 and 52 via the gas side stop valve 27
and the gas refrigerant communication pipe 7. The outdoor expansion
valve 38 is in a fully opened state. The liquid side stop valve 26
and the gas side stop valve 27 are in an opened state. The opening
degree of each of the indoor expansion valves 41 and 51 is adjusted
such that a superheat degree SHr of the refrigerant at the outlets
of the indoor heat exchangers 42 and 52 (i.e., the gas sides of the
indoor heat exchangers 42 and 52) becomes constant at a target
superheat degree SHrs. In the present embodiment, the superheat
degree SHr of the refrigerant at the outlet of each of the indoor
heat exchangers 42 and 52 is detected by subtracting the
refrigerant temperature (which corresponds to the evaporation
temperature Te) detected by the liquid side temperature sensors 44
and 54 from the refrigerant temperature detected by the gas side
temperature sensors 45 and 55, or is detected by converting the
suction pressure Ps of the compressor 21 detected by the suction
pressure sensor 29 to saturated temperature corresponding to the
evaporation temperature Te, and subtracting this saturated
temperature of the refrigerant from the refrigerant temperature
detected by the gas side temperature sensors 45 and 55. Note that,
although it is not employed in the present embodiment, a
temperature sensor that detects the temperature of the refrigerant
flowing through each of the indoor heat exchangers 42 and 52 may be
disposed such that the superheat degree SHr of the refrigerant at
the outlet of each of the indoor heat exchangers 42 and 52 is
detected by subtracting the refrigerant temperature corresponding
to the evaporation temperature Te which is detected by this
temperature sensor from the refrigerant temperature detected by the
gas side temperature sensors 45 and 55. In addition, the opening
degree of the bypass expansion valve 62 is adjusted such that a
superheat degree SHb of the refrigerant at the outlet on the bypass
refrigerant circuit side of the subcooler 25 becomes a target
superheat degree SHbs. In the present embodiment, the superheat
degree SHb of the refrigerant at the outlet on the bypass
refrigerant circuit side of the subcooler 25 is detected by
converting the suction pressure Ps of the compressor 21 detected by
the suction pressure sensor 29 to saturated temperature
corresponding to the evaporation temperature Te, and subtracting
this saturated temperature of the refrigerant from the refrigerant
temperature detected by the bypass temperature sensor 63. Note
that, although it is not employed in the present embodiment, a
temperature sensor may be disposed at an inlet on the bypass
refrigerant circuit side of the subcooler 25 such that the
superheat degree SHb of the refrigerant at the outlet on the bypass
refrigerant circuit side of the subcooler 25 is detected by
subtracting the refrigerant temperature detected by this
temperature sensor from the refrigerant temperature detected by the
bypass temperature sensor 63.
[0070] When the compressor 21, the outdoor fan 28, the indoor fans
43 and 53 are started in this state of the refrigerant circuit 10,
low-pressure gas refrigerant is sucked into the compressor 21 and
compressed into high-pressure gas refrigerant. Subsequently, the
high-pressure gas refrigerant is sent to the outdoor heat exchanger
23 via the four-way switching valve 22, exchanges heat with the
outdoor air supplied by the outdoor fan 28, and becomes condensed
into high-pressure liquid refrigerant. Then, this high-pressure
liquid refrigerant passes through the outdoor expansion valve 38,
flows into the subcooler 25, exchanges heat with the refrigerant
flowing in the bypass refrigerant circuit 61, is further cooled,
and becomes subcooled. At this time, a portion of the high-pressure
liquid refrigerant condensed in the outdoor heat exchanger 23 is
branched into the bypass refrigerant circuit 61 and is
depressurized by the bypass expansion valve 62. Subsequently, it is
returned to the suction side of the compressor 21. Here, the
refrigerant that passes through the bypass expansion valve 62 is
depressurized close to the suction pressure Ps of the compressor 21
and thereby a portion of the refrigerant evaporates. Then, the
refrigerant flowing from the outlet of the bypass expansion valve
62 of the bypass refrigerant circuit 61 toward the suction side of
the compressor 21 passes through the subcooler 25 and exchanges
heat with high-pressure liquid refrigerant sent from the outdoor
heat exchanger 23 on the main refrigerant circuit side to the
indoor units 4 and 5.
[0071] Then, the high-pressure liquid refrigerant that has become
subcooled is sent to the indoor units 4 and 5 via the liquid side
stop valve 26 and the liquid refrigerant communication pipe 6. The
high-pressure liquid refrigerant sent to the indoor units 4 and 5
is depressurized close to the suction pressure Ps of the compressor
21 by the indoor expansion valves 41 and 51, becomes refrigerant in
a low-pressure gas-liquid two-phase state, is sent to the indoor
heat exchangers 42 and 52, exchanges heat with the room air in the
indoor heat exchangers 42 and 52, and is evaporated into
low-pressure gas refrigerant.
[0072] This low-pressure gas refrigerant is sent to the outdoor
unit 2 via the gas refrigerant communication pipe 7, and flows into
the accumulator 24 via the gas side stop valve 27 and the four-way
switching valve 22. Then, the low-pressure gas refrigerant that
flowed into the accumulator 24 is again sucked into the compressor
21.
(Heating Operation)
[0073] Next, the heating operation in the normal operation mode is
described.
[0074] During the heating operation, the four-way switching valve
22 is in a state represented by the dotted lines in FIG. 1, i.e., a
state where the discharge side of the compressor 21 is connected to
the gas sides of the indoor heat exchangers 42 and 52 via the gas
side stop valve 27 and the gas refrigerant communication pipe 7 and
also the suction side of the compressor 21 is connected to the gas
side of the outdoor heat exchanger 23. The opening degree of the
outdoor expansion valve 38 is adjusted so as to be able to
depressurize the refrigerant that flows into the outdoor heat
exchanger 23 to a pressure where the refrigerant can evaporate
(i.e., evaporation pressure Pe) in the outdoor heat exchanger 23.
In addition, the liquid side stop valve 26 and the gas side stop
valve 27 are in an opened state. The opening degree of the indoor
expansion valves 41 and 51 is adjusted such that a subcooling
degree SCr of the refrigerant at the outlets of the indoor heat
exchangers 42 and 52 becomes constant at the target subcooling
degree SCrs. In the present embodiment, a subcooling degree SCr of
the refrigerant at the outlets of the indoor heat exchangers 42 and
52 is detected by converting the discharge pressure Pd of the
compressor 21 detected by the discharge pressure sensor 30 to
saturated temperature corresponding to the condensation temperature
Tc, and subtracting the refrigerant temperature detected by the
liquid side temperature sensors 44 and 54 from this saturated
temperature of the refrigerant. Note that, although it is not
employed in the present embodiment, a temperature sensor that
detects the temperature of the refrigerant flowing through each of
the indoor heat exchangers 42 and 52 may be disposed such that the
subcooling degree SCr of the refrigerant at the outlets of the
indoor heat exchangers 42 and 52 is detected by subtracting the
refrigerant temperature corresponding to the condensation
temperature Tc which is detected by this temperature sensor from
the refrigerant temperature detected by the liquid side temperature
sensors 44 and 54. In addition, the bypass expansion valve 62 is
closed.
[0075] When the compressor 21, the outdoor fan 28, the indoor fans
43 and 53 are started in this state of the refrigerant circuit 10,
low-pressure gas refrigerant is sucked into the compressor 21,
compressed into high-pressure gas refrigerant, and sent to the
indoor units 4 and 5 via the four-way switching valve 22, the gas
side stop valve 27, and the gas refrigerant communication pipe
7.
[0076] Then, the high-pressure gas refrigerant sent to the indoor
units 4 and 5 exchanges heat with the room air in the indoor heat
exchangers 42 and 52 and is condensed into high-pressure liquid
refrigerant. Subsequently, it is depressurized according to the
opening degree of the indoor expansion valves 41 and 51 when
passing through the indoor expansion valves 41 and 51.
[0077] The refrigerant that passed through the indoor expansion
valves 41 and 51 is sent to the outdoor unit 2 via the liquid
refrigerant communication pipe 6, is further depressurized via the
liquid side stop valve 26, the subcooler 25, and the outdoor
expansion valve 38, and then flows into the outdoor heat exchanger
23. Then, the refrigerant in a low-pressure gas-liquid two-phase
state that flowed into the outdoor heat exchanger 23 exchanges heat
with the outdoor air supplied by the outdoor fan 28, is evaporated
into low-pressure gas refrigerant, and flows into the accumulator
24 via the four-way switching valve 22. Then, the low-pressure gas
refrigerant that flowed into the accumulator 24 is again sucked
into the compressor 21.
[0078] Such operation control as described above in the normal
operation mode is performed by the controller 8 (more specifically,
the indoor side controllers 47 and 57, the outdoor side controller
37, and the transmission line 8a that connects between the
controllers 37, 47 and 57) that functions as a normal operation
controlling means to perform the normal operation that includes the
cooling operation and the heating operation.
<Test Operation Mode>
[0079] Next, the test operation mode is described with reference to
FIGS. 1 to 3. Here, FIG. 3 is a flowchart of the test operation
mode. In the present embodiment, in the test operation mode, first,
the automatic refrigerant charging operation in Step S1 is
performed, and subsequently, the pipe volume calculation process in
Step S2 is performed.
[0080] In the present embodiment, an example of a case is described
where, the outdoor unit 2 in which the refrigerant is charged in
advance and the indoor units 4 and 5 are installed at an
installation site such as a building, and the outdoor unit 2, the
indoor units 4, 5 are interconnected via the liquid refrigerant
communication pipe 6 and the gas refrigerant communication pipe 7
to configure the refrigerant circuit 10, and subsequently
additional refrigerant is charged into the refrigerant circuit 10
whose refrigerant quantity is insufficient according to the volumes
of the liquid refrigerant communication pipe 6 and the gas
refrigerant communication pipe 7.
(STEP S1: Automatic Refrigerant Charging Operation)
[0081] First, the liquid side stop valve 26 and the gas side stop
valve 27 of the outdoor unit 2 are opened and the refrigerant
circuit 10 is filled with the refrigerant that is charged in the
outdoor unit 2 in advance.
[0082] Next, when a worker performing the test operation connects a
refrigerant cylinder for additional charging to a service port (not
shown) of the refrigerant circuit 10 and issues a command to start
the test operation directly to the controller 8 or remotely by a
remote controller (not shown) and the like, the controller 8 starts
the process from Step S11 to Step S13 shown in FIG. 4. Here, FIG. 4
is a flowchart of the automatic refrigerant charging operation.
(STEP S11: Refrigerant Quantity Judging Operation)
[0083] When a command to start the automatic refrigerant charging
operation is issued, the refrigerant circuit 10, with the four-way
switching valve 22 of the outdoor unit 2 in the state represented
by the solid lines in FIG. 1, becomes a state where the indoor
expansion valves 41 and 51 of the indoor units 4 and 5 and the
outdoor expansion valve 38 are opened. Then, the compressor 21, the
outdoor fan 28, and the indoor fans 43 and 53 are started, and the
cooling operation is forcibly performed in all of the indoor units
4 and 5 (hereinafter referred to as "all indoor unit
operation").
[0084] Consequently, as shown in FIG. 5, in the refrigerant circuit
10, the high-pressure gas refrigerant compressed and discharged in
the compressor 21 flows along a flow path from the compressor 21 to
the outdoor heat exchanger 23 that functions as a condenser (see
the portion from the compressor 21 to the outdoor heat exchanger 23
in the hatching area indicated by the diagonal line in FIG. 5); the
high-pressure refrigerant that undergoes phase-change from a gas
state to a liquid state by heat exchange with the outdoor air flows
in the outdoor heat exchanger 23 that functions as a condenser (see
the portion corresponding to the outdoor heat exchanger 23 in the
hatching area indicated by the diagonal line and the
black-lacquered hatching area in FIG. 5); the high-pressure liquid
refrigerant flows along a flow path from the outdoor heat exchanger
23 to the indoor expansion valves 41 and 51 including the outdoor
expansion valve 38, the portion corresponding to the main
refrigerant circuit side of the subcooler 25 and the liquid
refrigerant communication pipe 6, and a flow path from the outdoor
heat exchanger 23 to the bypass expansion valve 62 (see the
portions from the outdoor heat exchanger 23 to the indoor expansion
valves 41 and 51 and to the bypass expansion valve 62 in the area
indicated by the black hatching in FIG. 5); the low-pressure
refrigerant that undergoes phase-change from a gas-liquid two-phase
state to a gas state by heat exchange with the room air flows in
the portions corresponding to the indoor heat exchangers 42 and 52
that function as evaporators and the portion corresponding to the
bypass refrigerant circuit side of the subcooler 25 (see the
portions corresponding to the indoor heat exchangers 42 and 52 and
the portion corresponding to the subcooler 25 in the area indicated
by the lattice hatching and the hatching indicated by the diagonal
line in FIG. 5); and the low-pressure gas refrigerant flows along a
flow path from the indoor heat exchangers 42 and 52 to the
compressor 21 including the gas refrigerant communication pipe 7
and the accumulator 24 and a flow path from the portion
corresponding to the bypass refrigerant circuit side of the
subcooler 25 to the compressor 21 (see the portion from the indoor
heat exchangers 42 and 52 to the compressor 21 and the portion from
the portion corresponding to the bypass refrigerant circuit side of
the subcooler 25 to the compressor 21 in the hatching area
indicated by the diagonal line in FIG. 5). FIG. 5 is a schematic
diagram to show a state of the refrigerant flowing in the
refrigerant circuit 10 in a refrigerant quantity judging operation
(illustrations of the four-way switching valve 22 and the like are
omitted).
[0085] Next, equipment control as described below is performed to
proceed to operation to stabilize the state of the refrigerant
circulating in the refrigerant circuit 10. Specifically, the indoor
expansion valves 41 and 51 are controlled such that the superheat
degree SHr of the indoor heat exchangers 42 and 52 that function as
evaporators becomes constant (hereinafter referred to as "super
heat degree control"); the operation capacity of the compressor 21
is controlled such that an evaporation pressure Pe becomes constant
(hereinafter referred to as "evaporation pressure control"); the
air flow rate Wo of outdoor air supplied to the outdoor heat
exchanger 23 by the outdoor fan 28 is controlled such that a
condensation pressure Pc of the refrigerant in the outdoor heat
exchanger 23 becomes constant (hereinafter referred to as
"condensation pressure control"); the operation capacity of the
subcooler 25 is controlled such that the temperature of the
refrigerant sent from the subcooler 25 to the indoor expansion
valves 41 and 51 becomes constant (hereinafter referred to as
"liquid pipe temperature control"); and the air flow rate Wr of
room air supplied to the indoor heat exchangers 42 and 52 by the
indoor fans 43 and 53 is maintained constant such that the
evaporation pressure Pe of the refrigerant is stably controlled by
the above described evaporation pressure control.
[0086] Here, the reason to perform the evaporation pressure control
is that the evaporation pressure Pe of the refrigerant in the
indoor heat exchangers 42 and 52 that function as evaporators is
greatly affected by the refrigerant quantity in the indoor heat
exchangers 42 and 52 where low-pressure refrigerant flows while
undergoing a phase change from a gas-liquid two-phase state to a
gas state as a result of heat exchange with the room air (see the
portions corresponding to the indoor heat exchangers 42 and 52 in
the area indicated by the lattice hatching and hatching indicated
by the diagonal line in FIG. 5, which is hereinafter referred to as
"evaporator portion C"). Consequently, here, a state is created in
which the refrigerant quantity in the evaporator portion C changes
mainly by the evaporation pressure Pe by causing the evaporation
pressure Pe of the refrigerant in the indoor heat exchangers 42 and
52 to become constant and by stabilizing the state of the
refrigerant flowing in the evaporator portion C as a result of
controlling the operation capacity of the compressor 21 by the
motor 21a whose rotation frequency Rm is controlled by an inverter.
Note that, the control of the evaporation pressure Pe by the
compressor 21 in the present embodiment is achieved in the
following manner: the refrigerant temperature (which corresponds to
the evaporation temperature Te) detected by the liquid side
temperature sensors 44 and 54 of the indoor heat exchangers 42 and
52 is converted to saturation pressure; the operation capacity of
the compressor 21 is controlled such that the saturation pressure
becomes constant at a target low pressure Pes (in other words, the
control to change the rotation frequency Rm of the motor 21a is
performed); and then a refrigerant circulation flow rate Wc flowing
in the refrigerant circuit 10 is increased or decreased. Note that,
although it is not employed in the present embodiment, the
operation capacity of the compressor 21 may be controlled such that
the suction pressure Ps of the compressor 21 detected by the
suction pressure sensor 29, which is the operation state quantity
equivalent to the pressure of the refrigerant at the evaporation
pressure Pe of the refrigerant in the indoor heat exchangers 42 and
52, becomes constant at the target low pressure Pes, or the
saturation temperature (which corresponds to the evaporation
temperature Te) corresponding to the suction pressure Ps becomes
constant at a target low pressure Tes. Also, the operation capacity
of the compressor 21 may be controlled such that the refrigerant
temperature (which corresponds to the evaporation temperature Te)
detected by the liquid side temperature sensors 44 and 54 of the
indoor heat exchangers 42 and 52 becomes constant at the target low
pressure Tes.
[0087] Then, by performing such evaporation pressure control, the
state of the refrigerant flowing in the refrigerant pipes from the
indoor heat exchangers 42 and 52 to the compressor 21 including the
gas refrigerant communication pipe 7 and the accumulator 24 (see
the portion from the indoor heat exchangers 42 and 52 to the
compressor 21 in the hatching area indicated by the diagonal line
in FIG. 5, which is hereinafter referred to as "gas refrigerant
distribution portion D") becomes stabilized, creating a state where
the refrigerant quantity in the gas refrigerant distribution
portion D changes mainly by the evaporation pressure Pe (i.e., the
suction pressure Ps), which is the operation state quantity
equivalent to the pressure of the refrigerant in the gas
refrigerant distribution portion D.
[0088] In addition, the reason to perform the condensation pressure
control is that the condensation pressure Pc of the refrigerant is
greatly affected by the refrigerant quantity in the outdoor heat
exchanger 23 where high-pressure refrigerant flows while undergoing
a phase change from a gas state to a liquid state as a result of
heat exchange with the outdoor air (see the portions corresponding
to the outdoor heat exchanger 23 in the area indicated by the
diagonal line hatching and the black hatching in FIG. 5, which is
hereinafter referred to as "condenser portion A"). The condensation
pressure Pc of the refrigerant in the condenser portion A greatly
changes due to the effect of the outdoor temperature Ta. Therefore,
the air flow rate Wo of the room air supplied from the outdoor fan
28 to the outdoor heat exchanger 23 is controlled by the motor 28a,
and thereby the condensation pressure Pc of the refrigerant in the
outdoor heat exchanger 23 is maintained constant and the state of
the refrigerant flowing in the condenser portion A is stabilized,
creating a state where the refrigerant quantity in condenser
portion A changes mainly by a subcooling degree SCo at the liquid
side of the outdoor heat exchanger 23 (hereinafter regarded as the
outlet of the outdoor heat exchanger 23 in the description
regarding the refrigerant quantity judging operation). Note that,
for the control of the condensation pressure Pc by the outdoor fan
28 in the present embodiment, the discharge pressure Pd of the
compressor 21 detected by the discharge pressure sensor 30, which
is the operation state quantity equivalent to the condensation
pressure Pc of the refrigerant in the outdoor heat exchanger 23, or
the temperature of the refrigerant flowing through the outdoor heat
exchanger 23 (i.e., the condensation temperature Tc) detected by
the heat exchanger temperature sensor 33 is used.
[0089] Then, by performing such condensation pressure control, the
high-pressure liquid refrigerant flows along a flow path from the
outdoor heat exchanger 23 to the indoor expansion valves 41 and 51
including the outdoor expansion valve 38, the portion on the main
refrigerant circuit side of the subcooler 25, and the liquid
refrigerant communication pipe 6 and a flow path from the outdoor
heat exchanger 23 to the bypass expansion valve 62 of the bypass
refrigerant circuit 61; the pressure of the refrigerant in the
portions from the outdoor heat exchanger 23 to the indoor expansion
valves 41 and 51 and to the bypass expansion valve 62 (see the area
indicated by the black hatching in FIG. 5, which is hereinafter
referred to as "liquid refrigerant distribution portion B") also
becomes stabilized; and the liquid refrigerant distribution portion
B is sealed by the liquid refrigerant, thereby becoming a stable
state.
[0090] In addition, the reason to perform the liquid pipe
temperature control is to prevent a change in the density of the
refrigerant in the refrigerant pipes from the subcooler 25 to the
indoor expansion valves 41 and 51 including the liquid refrigerant
communication pipe 6 (see the portion from the subcooler 25 to the
indoor expansion valves 41 and 51 in the liquid refrigerant
distribution portion B shown in FIG. 5). Performance of the
subcooler 25 is controlled by increasing or decreasing the flow
rate of the refrigerant flowing in the bypass refrigerant circuit
61 such that the refrigerant temperature T1p detected by the liquid
pipe temperature sensor 35 disposed at the outlet on the main
refrigerant circuit side of the subcooler 25 becomes constant at a
target liquid pipe temperature T1ps, and by adjusting the quantity
of heat exchange between the refrigerant flowing through the main
refrigerant circuit side and the refrigerant flowing through the
bypass refrigerant circuit side of the subcooler 25. Note that, the
flow rate of the refrigerant flowing in the bypass refrigerant
circuit 61 is increased or decreased by adjustment of the opening
degree of the bypass expansion valve 62. In this way, the liquid
pipe temperature control is achieved in which the refrigerant
temperature in the refrigerant pipes from the subcooler 25 to the
indoor expansion valves 41 and 51 including the liquid refrigerant
communication pipe 6 becomes constant.
[0091] Then, by performing such liquid pipe temperature constant
control, even when the refrigerant temperature Tco at the outlet of
the outdoor heat exchanger 23 (i.e., the subcooling degree SCo of
the refrigerant at the outlet of the outdoor heat exchanger 23)
changes along with a gradual increase in the refrigerant quantity
in the refrigerant circuit 10 by charging refrigerant into the
refrigerant circuit 10, the effect of a change in the refrigerant
temperature Tco at the outlet of the outdoor heat exchanger 23 will
remain only within the refrigerant pipes from the outlet of the
outdoor heat exchanger 23 to the subcooler 25, and the effect will
not extend to the refrigerant pipes from the subcooler 25 to the
indoor expansion valves 41 and 51 including the liquid refrigerant
communication pipe 6 in the liquid refrigerant distribution portion
B.
[0092] Further, the reason to perform the superheat degree control
is because the refrigerant quantity in the evaporator portion C
greatly affects the quality of wet vapor of the refrigerant at the
outlets of the indoor heat exchangers 42 and 52. The superheat
degree SHr of the refrigerant at the outlets of the indoor heat
exchangers 42 and 52 is controlled such that the superheat degree
SHr of the refrigerant at the gas sides of the indoor heat
exchangers 42 and 52 (hereinafter regarded as the outlets of the
indoor heat exchangers 42 and 52 in the description regarding the
refrigerant quantity judging operation) becomes constant at the
target superheat degree SHrs (in other words, the gas refrigerant
at the outlets of the indoor heat exchangers 42 and 52 is in a
superheat state) by controlling the opening degree of the indoor
expansion valves 41 and 51, and thereby the state of the
refrigerant flowing in the evaporator portion C is stabilized.
[0093] Consequently, by performing such superheat degree control, a
state is created in which the gas refrigerant reliably flows into
the gas refrigerant communication portion D.
[0094] By various control described above, the state of the
refrigerant circulating in the refrigerant circuit 10 becomes
stabilized, and the distribution of the refrigerant quantity in the
refrigerant circuit 10 becomes constant. Therefore, when
refrigerant starts to be charged into the refrigerant circuit 10 by
additional refrigerant charging, which is subsequently performed,
it is possible to create a state where a change in the refrigerant
quantity in the refrigerant circuit 10 mainly appears as a change
of the refrigerant quantity in the outdoor heat exchanger 23
(hereinafter this operation is referred to as "refrigerant quantity
judging operation").
[0095] Such operation control as described above is performed as
the process in Step S11 by the controller 8 (more specifically, the
indoor side controllers 47, 57, the outdoor side controller 37, and
the transmission line 8a that connects between the controllers 37,
47 and 57) that functions as a normal operation controlling means
to perform the refrigerant quantity judging operation.
(STEP S12: Refrigerant Quantity Calculation)
[0096] Next, additional refrigerant is charged into the refrigerant
circuit 10 during performing the above described refrigerant
quantity judging operation. At this time, the controller 8 that
functions as refrigerant quantity calculating means calculates the
refrigerant quantity in the refrigerant circuit 10 from the
operation state quantity of constituent equipment or refrigerant
flowing in the refrigerant circuit 10 during additional refrigerant
charging in Step S12.
[0097] First, the refrigerant quantity calculating means in the
present embodiment is described. The refrigerant quantity
calculating means divides the refrigerant circuit 10 into a
plurality of portions, calculates the refrigerant quantity for each
divided portion, and thereby calculates the refrigerant quantity in
the refrigerant circuit 10. More specifically, a relational
expression between the refrigerant quantity in each portion and the
operation state quantity of constituent equipment or refrigerant
flowing in the refrigerant circuit 10 is set for each divided
portion, and the refrigerant quantity in each portion can be
calculated by using these relational expressions. In the present
embodiment, in a state where the four-way switching valve 22 is
represented by the solid lines in FIG. 1, i.e., a state where the
discharge side of the compressor 21 is connected to the gas side of
the outdoor heat exchanger 23 and where the suction side of the
compressor 21 is connected to the outlets of the indoor heat
exchangers 42 and 52 via the gas side stop valve 27 and the gas
refrigerant communication pipe 7, the refrigerant circuit 10 is
divided into the following portions and a relational expression is
set for each portion: a portion corresponding to the compressor 21
and a portion from the compressor 21 to the outdoor heat exchanger
23 including the four-way switching valve 22 (not shown in FIG. 5)
(hereinafter referred to as "high-pressure gas pipe portion E"); a
portion corresponding to the outdoor heat exchanger 23 (i.e., the
condenser portion A); a portion from the outdoor heat exchanger 23
to the subcooler 25 and an inlet side half of the portion
corresponding to the main refrigerant circuit side of the subcooler
25 in the liquid refrigerant distribution portion B (hereinafter
referred to as "high temperature side liquid pipe portion B1"); an
outlet side half of a portion corresponding to the main refrigerant
circuit side of the subcooler 25 and a portion from the subcooler
25 to the liquid side stop valve 26 (not shown in FIG. 5) in the
liquid refrigerant distribution portion B (hereinafter referred to
as "low temperature side liquid pipe portion B2"); a portion
corresponding to the liquid refrigerant communication pipe 6 in the
liquid refrigerant distribution portion B (hereinafter referred to
as "liquid refrigerant communication pipe portion B3"); a portion
from the liquid refrigerant communication pipe 6 in the liquid
refrigerant distribution portion B to the gas refrigerant
communication pipe 7 in the gas refrigerant distribution portion D
including portions corresponding to the indoor expansion valves 41
and 51 and the indoor heat exchangers 42 and 52 (i.e., the
evaporator portion C) (hereinafter referred to as "indoor unit
portion F"); a portion corresponding to the gas refrigerant
communication pipe 7 in the gas refrigerant distribution portion D
(hereinafter referred to as "gas refrigerant communication pipe
portion G"); a portion from the gas side stop valve 27 (not shown
in FIG. 5) in the gas refrigerant distribution portion D to the
compressor 21 including the four-way switching valve 22 and the
accumulator 24 (hereinafter referred to as "low-pressure gas pipe
portion H"); and a portion from the high temperature side liquid
pipe portion B1 in the liquid refrigerant distribution portion B to
the low-pressure gas pipe portion H including the bypass expansion
valve 62 and a portion corresponding to the bypass refrigerant
circuit side of the subcooler 25 (hereinafter referred to as
"bypass circuit portion I"). Next, the relational expressions set
for each portion described above are described.
[0098] In the present embodiment, a relational expression between a
refrigerant quantity Mog1 in the high-pressure gas pipe portion E
and the operation state quantity of constituent equipment or
refrigerant flowing in the refrigerant circuit 10 is, for example,
expressed by
Mog1=Vog1.times..rho.d,
which is a function expression in which a volume Vog1 of the
high-pressure gas pipe portion E in the outdoor unit 2 is
multiplied by the density .rho.d of the refrigerant in
high-pressure gas pipe portion E. Note that, the volume Vog1 of the
high-pressure gas pipe portion E is a value that is known prior to
installation of the outdoor unit 2 at the installation site and is
stored in advance in the memory of the controller 8. In addition, a
density pd of the refrigerant in the high-pressure gas pipe portion
E is obtained by converting the discharge temperature Td and the
discharge pressure Pd.
[0099] A relational expression between a refrigerant quantity Mc in
the condenser portion A and the operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit 10 is, for example, expressed by
Mc=kc1.times.Ta+kc2.times.Tc+kc3.times.SHm+kc4.times.Wc+kc5.times..rho.c-
+kc6.times..rho.co+kc7,
which is a function expression of the outdoor temperature Ta, the
condensation temperature Tc, a compressor discharge superheat
degree SHm, the refrigerant circulation flow rate Wc, the saturated
liquid density .rho.c of the refrigerant in the outdoor heat
exchanger 23, and the density .rho.co of the refrigerant at the
outlet of the outdoor heat exchanger 23. Note that, the parameters
kc1 to kc7 in the above described relational expression are derived
from a regression analysis of results of tests and detailed
simulations and are stored in advance in the memory of the
controller 8. In addition, the compressor discharge superheat
degree SHm is a superheat degree of the refrigerant at the
discharge side of the compressor, and is obtained by converting the
discharge pressure Pd to refrigerant saturation temperature and
subtracting this refrigerant saturation temperature from the
discharge temperature Td. The refrigerant circulation flow rate Wc
is expressed as a function of the evaporation temperature Te and
the condensation temperature Tc (i.e., Wc=f(Te, Tc)). A saturated
liquid density .rho.c of the refrigerant is obtained by converting
the condensation temperature Tc. A density .rho.co of the
refrigerant at the outlet of the outdoor heat exchanger 23 is
obtained by converting the condensation pressure Pc which is
obtained by converting the condensation temperature Tc and the
refrigerant temperature Tco.
[0100] A relational expression between a refrigerant quantity Mol1
in the high temperature liquid pipe portion B1 and the operation
state quantity of constituent equipment or refrigerant flowing in
the refrigerant circuit 10 is, for example, expressed by
Mol1=Vol1.times..rho.co,
which is a function expression in which a volume Vol1 of the high
temperature liquid pipe portion B1 in the outdoor unit 2 is
multiplied by the density .rho.co of the refrigerant in the high
temperature liquid pipe portion B1 (i.e., the above described
density of the refrigerant at the outlet of the outdoor heat
exchanger 23). Note that, the volume Vol1 of the high-pressure
liquid pipe portion B1 is a value that is known prior to
installation of the outdoor unit 2 at the installation site and is
stored in advance in the memory of the controller 8.
[0101] A relational expression between a refrigerant quantity Mol2
in the low temperature liquid pipe portion B2 and the operation
state quantity of constituent equipment or refrigerant flowing in
the refrigerant circuit 10 is, for example, expressed by
Mol2=Vol2.times..rho.lp,
which is a function expression in which a volume Vol2 of the low
temperature liquid pipe portion B2 in the outdoor unit 2 is
multiplied by a density .rho.12p of the refrigerant in the low
temperature liquid pipe portion B2. Note that, the volume Vol2 of
the low temperature liquid pipe portion B2 is a value that is known
prior to installation of the outdoor unit 2 at the installation
site and is stored in advance in the memory of the controller 8. In
addition, the density .rho.lp of the refrigerant in the low
temperature liquid pipe portion B2 is the density of the
refrigerant at the outlet of the subcooler 25, and is obtained by
converting the condensation pressure Pc and the refrigerant
temperature T1p at the outlet of the subcooler 25.
[0102] A relational expression between a refrigerant quantity M1p
in the liquid refrigerant communication pipe portion B3 and the
operation state quantity of constituent equipment or refrigerant
flowing in the refrigerant circuit 10 is, for example, expressed
by
M1p=V1p.times..rho.1p,
which is a function expression in which a volume V1p of the liquid
refrigerant communication pipe 6 is multiplied by the density
.rho.1p of the refrigerant in the liquid refrigerant communication
pipe portion B3 (i.e., the density of the refrigerant at the outlet
of the subcooler 25).
[0103] A relational expression between a refrigerant quantity Mr in
the indoor unit portion F and the operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit 10 is, for example, expressed by
Mr=kr1.times.T1p+kr2.times..DELTA.T+kr3.times.SHr+kr4.times.Wr+kr5,
which is a function expression of the refrigerant temperature T1p
at the outlet of the subcooler 25, a temperature difference
.DELTA.T in which the evaporation temperature Te is subtracted from
the room temperature Tr, the superheat degree SHr of the
refrigerant at the outlets of the indoor heat exchangers 42 and 52,
and the air flow rate Wr of the indoor fans 43 and 53. Note that,
the parameters kr1 to kr5 in the above described relational
expression are derived from a regression analysis of results of
tests and detailed simulations and are stored in advance in the
memory of the controller 8. Note that, here, the relational
expression for the refrigerant quantity Mr is set for each of the
two indoor units 4 and 5, and the total refrigerant quantity in the
indoor unit portion F is calculated by adding the refrigerant
quantity Mr in the indoor unit 4 to the refrigerant quantity Mr in
the indoor unit 5. Note that relational expressions in each portion
having parameters kr1 to kr5 with different values will be used
when the indoor unit 4 and the indoor unit 5 are different in terms
of the model and the capacity.
[0104] A relational expression between a refrigerant quantity Mgp
in the gas refrigerant communication pipe portion G and the
operation state quantity of constituent equipment or refrigerant
flowing in the refrigerant circuit 10 is, for example, expressed
by
Mgp=Vgp.times..rho.gp,
which is a function expression in which a volume Vgp of the gas
refrigerant communication pipe 7 is multiplied by a density .rho.gp
of the refrigerant in the gas refrigerant communication pipe
portion H. In addition, the density .rho.gp of the refrigerant in
the gas refrigerant communication pipe portion G is an average
value between a density .rho.s of the refrigerant at the suction
side of the compressor 21 and a density .rho.eo of the refrigerant
at the outlets of the indoor heat exchangers 42 and 52 (i.e., the
inlet of the gas refrigerant communication pipe 7). The density
.rho.s of the refrigerant is obtained by converting the suction
pressure Ps and the suction temperature Ts, and a density .rho.eo
of the refrigerant is obtained by converting the evaporation
pressure Pe, which is a converted value of the evaporation
temperature Te, and the outlet temperature Teo of the indoor heat
exchangers 42 and 52.
[0105] A relational expression between a refrigerant quantity Mog2
in the low-pressure gas pipe portion H and the operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit 10 is, for example, expressed by
Mog2=Vog2.times..rho.s,
which is a function expression in which a volume Vog2 of the
low-pressure gas pipe portion H in the outdoor unit 2 is multiplied
by the density .rho.s of the refrigerant in the low-pressure gas
pipe portion H. Note that, the volume Vog2 of the low-pressure gas
pipe portion H is a value that is known prior to shipment to the
installation site and is stored in advance in the memory of the
controller 8.
[0106] A relational expression between a refrigerant quantity Mob
in the bypass circuit portion I and the operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit 10 is, for example, expressed by
Mob=kob1.times..rho.co+kob2.times..rho.s+kob3.times.Pe+kob4,
which is a function expression of a density .rho.co of the
refrigerant at the outlet of the outdoor heat exchanger 23, and the
density .rho.s and evaporation pressure Pe of the refrigerant at
the outlet on the bypass circuit side of the subcooler 25. Note
that, the parameters kob1 to kob3 in the above described relational
expression are derived from a regression analysis of results of
tests and detailed simulations and are stored in advance in the
memory of the controller 8. In addition, the refrigerant quantity
Mob of the bypass circuit portion I may be calculated using a
simpler relational expression because the refrigerant quantity
there is smaller compared to the other portions. For example, it is
expressed as follows:
Mob=Vob.times..rho.e.times.kob5,
which is a function expression in which a volume Vob of the bypass
circuit portion I is multiplied by the saturated liquid density
.rho.e at the portion corresponding to the bypass circuit side of
the subcooler 25 and a correct coefficient kob 5. Note that, the
volume Vob of the bypass circuit portion I is a value that is known
prior to installation of the outdoor unit 2 at the installation
site and is stored in advance in the memory of the controller 8. In
addition, the saturated liquid density .rho.e at the portion
corresponding to the bypass circuit side of the subcooler 25 is
obtained by converting the suction pressure Ps or the evaporation
temperature Te.
[0107] Note that, in the present embodiment, one outdoor unit 2 is
provided. However, when a plurality of outdoor units are connected,
as for the refrigerant quantity in the outdoor unit such as Mog1,
Mc, Mol1, Mol2, Mog2, and Mob, the relational expression for the
refrigerant quantity in each portion is set for each of the
plurality of outdoor units, and the entire refrigerant quantity in
the outdoor units is calculated by adding the refrigerant quantity
in each portion of the plurality of the outdoor units.
[0108] As described above, in the present embodiment, by using the
relational expressions for each portion in the refrigerant circuit
10, the refrigerant quantity in each portion is calculated from the
operation state quantity of constituent equipment or refrigerant
flowing in the refrigerant circuit 10 in the refrigerant quantity
judging operation, and thereby the refrigerant quantity in the
refrigerant circuit 10 can be calculated.
[0109] Further, this Step S12 is repeated until the condition for
judging the adequacy of the refrigerant quantity in the below
described Step S13 is satisfied. Therefore, in the period from the
start to the completion of additional refrigerant charging, the
refrigerant quantity in each portion is calculated from the
operation state quantity during refrigerant charging by using the
relational expressions for each portion in the refrigerant circuit
10. More specifically, a refrigerant quantity Mo in the outdoor
unit 2 and the refrigerant quantity Mr in each of the indoor units
4 and 5 (i.e., the refrigerant quantity in each portion in the
refrigerant circuit 10 excluding the refrigerant communication
pipes 6 and 7) necessary for judgment of the adequacy of the
refrigerant quantity in the below described Step S13 are
calculated. Here, the refrigerant quantity Mo in the outdoor unit 2
is calculated by adding Mog1, Mc, Mol1, Mol2, Mog2, and Mob
described above, each of which is the refrigerant quantity in each
portion in the outdoor unit 2.
[0110] In this way, the process in Step S12 is performed by the
controller 8 that functions as the refrigerant quantity calculating
means for calculating the refrigerant quantity in each portion in
the refrigerant circuit 10 from the operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit 10 in the automatic refrigerant charging operation.
(STEP S13: Judgment of the Adequacy of the Refrigerant
Quantity)
[0111] As described above, when additional refrigerant charging
into the refrigerant circuit 10 starts, the refrigerant quantity in
the refrigerant circuit 10 gradually increases. Here, when the
volumes of the refrigerant communication pipes 6 and 7 are unknown,
the refrigerant quantity that should be charged into the
refrigerant circuit 10 after additional refrigerant charging cannot
be prescribed as a total charging refrigerant quantity Mt that is a
refrigerant quantity in the entire refrigerant circuit 10. However,
when the focus is placed only on the outdoor unit 2 and the indoor
units 4 and 5 (i.e., the refrigerant circuit 10 excluding the
refrigerant communication pipes 6 and 7), it is possible to know in
advance the optimal refrigerant quantity Mo in the outdoor unit 2
and the optimal refrigerant quantities Mr in the indoor units 4 and
5 by tests and detailed simulations. Therefore, additional
refrigerant can be charged by the following manner: a refrigerant
quantity that satisfies these optimal refrigerant quantities is
stored in advance in the memory of the controller 8 as a target
charging value Ms; the refrigerant quantity Mo in the outdoor unit
2 and the refrigerant quantities Mr in the indoor units 4 and 5 are
calculated from the operation state quantity of constituent
equipment or refrigerant flowing in the refrigerant circuit 10 in
the automatic refrigerant charging operation by using the above
described relational expressions; and additional refrigerant is
charged until a value (hereinafter referred to as an inside-unit
refrigerant quantity Mu) of the refrigerant quantity obtained by
adding the refrigerant quantity Mo to the refrigerant quantities Mr
(i.e., the refrigerant quantity in the refrigerant circuit 10
excluding the refrigerant communication pipes 6 and 7) reaches the
target charging value Ms. In other words, Step S13 is a process to
judge the adequacy of the refrigerant quantity charged in the
refrigerant circuit 10, by additional refrigerant charging by
judging whether or not the inside-unit refrigerant quantity Mu in
the automatic refrigerant charging operation has reached the target
charging value Ms.
[0112] Further, in Step S13, when a value of the inside-unit
refrigerant quantity Mu is smaller than the target charging value
Ms and additional refrigerant charging has not been completed, the
process in Step S13 is repeated until the target charging value Ms
is reached. In addition, when the inside-unit refrigerant quantity
Mu reaches the target charging value Ms, the display 9b displays a
message indicating that the additional refrigerant charging is
completed, the refrigerant supply from the refrigerant cylinder is
stopped, and Step S1 as the automatic refrigerant charging
operation process is completed.
[0113] In this way, the process in Step S13 is performed by the
controller 8 that functions as an automatic refrigerant charging
judging means which is one of the refrigerant quantity judging
means to judge the adequacy of the refrigerant quantity in the
refrigerant circuit 10 in the refrigerant quantity judging
operation of the automatic refrigerant charging operation (i.e., to
judge whether or not the refrigerant quantity has reached the
target charging value Ms). Then, by this automatic refrigerant
charging operation, a state is reached where the total charged
refrigerant quantity Mt is charged in the refrigerant circuit 10.
the total charged refrigerant quantity Mt is the refrigerant
quantity obtained by adding an additional charging quantity Ma that
is a refrigerant quantity additionally charged to an initial
charging quantity Mi that is a refrigerant quantity that has been
charged into the refrigerant circuit 10 before the automatic
refrigerant charging operation (i.e., the refrigerant quantity
charged in the outdoor unit 2 in advance).
(STEP S2: Pipe Volume Calculation)
[0114] When the above described automatic refrigerant charging
operation in Step S1 is completed, the process proceeds to the pipe
volume calculation process in Step S2. In this pipe volume
calculation process, the process from Steps S21 to S24 shown in
FIG. 6 is performed by the controller 8 that functions as a pipe
volume calculating means that calculates the volumes of the
refrigerant communication pipes 6 and 7 based on the additional
charging quantity Ma. Here, FIG. 6 is a flowchart of the pipe
volume calculation process.
(STEPS S21, S22: Storing Data from the Automatic Refrigerant
Charging Operation and Inputting Additional Charging Quantity)
[0115] In Step S21, the operation data from the above described
automatic refrigerant charging operation is stored in the memory of
the controller 8 such that the density of the refrigerant flowing
through the refrigerant communication pipes 6 and 7 can be
calculated in the below described Step S23. Here, the data stored
in the memory of the controller 8 includes: condensation pressure
Pc and temperature T1p of the refrigerant at the outlet of the
subcooler 25 required for the calculation of the density pip of the
refrigerant in the liquid refrigerant communication pipe portion
B3; suction pressure Ps, suction temperature Ts, evaporation
pressure Pe, and outlet temperature Teo required for the
calculation of the density .rho.gp of the refrigerant in the gas
refrigerant communication pipe portion H; and the inside-unit
refrigerant quantity Mu at the time of completion of the automatic
refrigerant charging operation.
[0116] In Step S22, a value of the additional charging quantity Ma
or a value of the total charged refrigerant quantity Mt including
the additional charging quantity Ma is input in the memory of the
controller 8 through the input unit 9a. Here, the additional
charging quantity Ma is a value of the refrigerant quantity
obtained from the change in the weight of the refrigerant cylinder
and the like in the automatic refrigerant charging operation. The
additional charging quantity Ma may be manually input in the memory
of the controller 8 through the input unit 9a provided in the
controller 8 by an operator or the like who performs additional
charging, or may be automatically input in the memory of the
controller 8 by connecting a scale for measuring the change in the
weight of the refrigerant cylinder as the input unit 9a to the
controller 8.
[0117] Note that, here, the process of Steps S21 and S22 is
performed in the process of the pipe volume calculation, however,
the process may be performed in the process of the above described
automatic refrigerant charging operation.
(STEPS S23, S24: Calculation of Communication Pipe Refrigerant
Quantity, Calculation of Density, Calculation of Pipe Volume)
[0118] In Step S23, first, the total charged refrigerant quantity
Mt, which is the refrigerant quantity in the entire refrigerant
circuit 10 immediately after the automatic refrigerant charging
operation, is obtained by adding the additional charging quantity
Ma input in the controller 8 in Step S22 to the initial charging
quantity Mi that is the refrigerant quantity that has been charged
in the refrigerant circuit 10 before the automatic refrigerant
charging operation. Here, the initial charging quantity Mi is
stored in the memory of the controller 8. Next, the inside-unit
refrigerant quantity Mu (or the target charging quantity Ms) stored
in the controller 8 in Step S21 is subtracted from the total
charged refrigerant quantity Mt, and thereby the communication pipe
refrigerant quantity Mp that is the refrigerant quantity in the
refrigerant communication pipes 6 and 7 is determined.
[0119] In addition, in Step S23, based on the condensation pressure
Pc and the temperature T1p of the refrigerant at the outlet of the
subcooler 25 stored in the controller 8 in Step S21, the density
.rho.1p of liquid refrigerant flowing through the liquid
refrigerant communication pipe portion B 3 (i.e., the liquid
refrigerant communication pipe 6) during the automatic refrigerant
charging operation is determined. In addition, based on the suction
pressure Ps, the suction temperature Ts, the evaporation pressure
Pe, and the outlet temperature Teo stored in the controller 8 in
Step S21, the density .rho.gp of gas refrigerant flowing through
the gas refrigerant communication pipe portion H (i.e., the gas
refrigerant communication pipe 7) during the automatic refrigerant
charging operation is determined (note that the calculation of
these densities .rho.1p and .rho.gp is the same as the calculation
of the densities .rho.1p and .rho.gp for the calculation of the
refrigerant quantity in Step S12 of the above described automatic
refrigerant charging operation, and thus the description thereof is
omitted here).
[0120] In Step S24, the volumes of the refrigerant communication
pipes 6 and 7 (more specifically, the volume V1p of the liquid
refrigerant communication pipe 6 and the volume Vgp of the gas
refrigerant communication pipe) are calculated based on the
communication pipe refrigerant quantity Mp and the densities
.rho.1p and .rho.gp determined in Step S23.
[0121] Here, first, the calculation method of the volumes of the
refrigerant communication pipes 6 and 7 in the present embodiment
is described.
[0122] The liquid refrigerant communication pipe 6 and the gas
refrigerant communication pipe 7 are provided so as to interconnect
the indoor units 4 and 5 and the outdoor unit 2, so that these
pipes have substantially the same pipe length but different pipe
diameters, i.e., different flow passage cross-sectional areas, due
to the different densities of the refrigerant flowing through the
pipes. Therefore, the volume ratio between the liquid refrigerant
communication pipe 6 and the gas refrigerant communication pipe 7
(in the description below, a value of Vgp/V1p in which the gas
refrigerant communication pipe Vgp is divided by the volume V1quid
refrigerant communication pipe 6 is referred to as a volume ratio
Rv) will substantially correspond to the flow passage
cross-sectional area ratio between these pipes, and furthermore,
this volume ratio Rv will be within a certain range because the
flow passage cross-sectional area ratio is predetermined based on
the capacities and models of the indoor units 4 and 5 and the
outdoor unit 2.
[0123] Further, if the volume ratio Rv between the liquid
refrigerant communication pipe 6 and the gas refrigerant
communication pipe 7 is known, a total value obtained by adding a
value of the multiplication between the volume V1e liquid
refrigerant communication pipe 6 and the liquid refrigerant density
.rho.1of the multiplication between the volume Vgp of the gas
refrigerant communication pipe 7 and the gas refrigerant density
.rho.will be equal to the communication pipe refrigerant quantity
Mp, as in the following expression:
Vlp .times. .rho. lp + Vgp .times. .rho. gp = Vlp .times. .rho. lp
+ ( Vlp .times. Rv ) .times. .rho. gp = Vlp .times. ( .rho. lp + Rv
.times. .rho. gp ) = Mp . ##EQU00001##
Thereby, the volume V1e liquid refrigerant communication pipe can
be calculated as follows:
V1p=Mp/(.rho.1p+Rv.times..rho.gp),
and the volume Vgp of the gas refrigerant communication pipe 7 can
be calculated as follows:
Vg p=V1p.times.Rv.
[0124] In addition, in the present embodiment, the volume ratio Rv
between the liquid refrigerant communication pipe 6 and the gas
refrigerant communication pipe 7 is stored in the memory of the
controller 8 in advance as a value corresponding to the capacities
and models of the indoor units 4, 5 and the outdoor unit 2, then
the volumes of the refrigerant communication pipes 6 and 7 (more
specifically, the volume V1e liquid refrigerant communication pipe
6 and the volume Vgp of the gas refrigerant communication pipe) are
calculated using the above described calculation equations, based
on the communication pipe refrigerant quantity Mp, the densities
.rho.1and .rho.gp determined in Step S23 and the volume ratio
Rv.
<Refrigerant Leak Detection Operation Mode>
[0125] Next, the refrigerant leak detection operation mode is
described with reference to FIGS. 1, 2, 5, and 7. Here, FIG. 7 is a
flowchart of the refrigerant leak detection operation mode.
[0126] In the present embodiment, an example of a case is described
where, whether or not the refrigerant in the refrigerant circuit 10
is leaking to the outside due to an unforeseen factor is detected
periodically (for example, during a period of time such as on a
holiday or in the middle of the night when air conditioning is not
needed).
(STEP S31: Refrigerant Quantity Judging Operation)
[0127] First, when operation in the normal operation mode such as
the above described cooling operation and heating operation has
gone on for a certain period of time (for example, half a year to a
year), the normal operation mode is automatically or manually
switched to the refrigerant leak detection operation mode, and as
is the case with the refrigerant quantity judging operation of the
initial refrigerant quantity detection operation, the refrigerant
quantity judging operation, including the all indoor unit
operation, condensation pressure control, liquid pipe temperature
control, superheat degree control, and evaporation pressure
control, is performed. Here, as a rule, values that are the same as
the target values in Step S11 of the refrigerant quantity judging
operation of the automatic refrigerant charging operation are used
for the target liquid pipe temperature T1ps in the liquid pipe
temperature control, the target superheat degree SHrs in the
superheat degree control, and the target low pressure Pes in the
evaporation pressure control.
[0128] Note that, this refrigerant quantity judging operation is
performed for each time the refrigerant leak detection operation is
performed. Even when the refrigerant temperature Tco at the outlet
of the outdoor heat exchanger 23 fluctuates due to the different
operating conditions, for example, such as when the condensation
pressure Pc is different or when there is a refrigerant leak, the
refrigerant temperature T1p in the liquid refrigerant communication
pipe 6 is maintained constant at the same target liquid pipe
temperature T1ps by the liquid pipe temperature control.
[0129] In this way, the process in Step S31 is performed by the
controller 8 that functions as the refrigerant quantity judging
operation controlling means for performing the refrigerant quantity
judging operation, including the all indoor unit operation,
condensation pressure control, liquid pipe temperature control,
superheat degree control, and evaporation pressure control.
(STEP S32: Refrigerant Quantity Calculation)
[0130] Next, the refrigerant quantity in the refrigerant circuit 10
is calculated from the operation state quantity of constituent
equipment or refrigerant flowing in the refrigerant circuit 10 in
the refrigerant leak detection operation in Step S32 by the
controller 8 that functions as the refrigerant quantity calculating
means during performing the above described refrigerant quantity
judging operation. Calculation of the refrigerant quantity in the
refrigerant circuit 10 is performed by using the above described
relational expression between the refrigerant quantity in each
portion in the refrigerant circuit 10 and the operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit 10. However, at this time, the volumes V1p and
Vgp of the refrigerant communication pipes 6 and 7, which were
unknown at the time of after installation of constituent equipment
of the air conditioner 1, have been calculated and the values
thereof are known by the above described pipe volume calculation
process. Thus, by multiplying the volumes V1p and Vgp of the
refrigerant communication pipes 6 and 7 by the density of the
refrigerant, the refrigerant quantities M1p, Mgp in the refrigerant
communication pipes 6 and 7 can be calculated, and further by
adding the refrigerant quantity in each of the other portions (for
the calculation of the refrigerant in each of other portions, see
Step S12 of the automatic refrigerant charging operation), the
refrigerant quantity in the entire refrigerant circuit 10
(hereinafter referred to as "total calculated refrigerant quantity
M") can be calculated.
[0131] Here, as described above, the refrigerant temperature T1p in
the liquid refrigerant communication pipe 6 is maintained constant
at the target liquid pipe temperature T1ps by the liquid pipe
temperature control. Therefore, regardless the difference in the
operating conditions for the refrigerant leak detection operation,
the refrigerant quantity M1p in the liquid refrigerant
communication pipe portion B3 will be maintained constant even when
the refrigerant temperature Tco at the outlet of the outdoor heat
exchanger 23 changes.
[0132] In this way, the process in Step S32 is performed by the
controller 8 that functions as the refrigerant quantity calculating
means for calculating the refrigerant quantity at each portion in
the refrigerant circuit 10 from the operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit 10 in the refrigerant leak detection operation.
(STEPS S33, S34: Adequacy Judgment of the Refrigerant Quantity,
Warning Display)
[0133] When refrigerant leaks from the refrigerant circuit 10, the
refrigerant quantity in the refrigerant circuit 10 decreases. Then,
when the refrigerant quantity in the refrigerant circuit 10
decreases, mainly, a tendency of a decrease in the subcooling
degree SC.sub.o at the outlet of the outdoor heat exchanger 23
appears. Along with this, the refrigerant quantity Mc in the
outdoor heat exchanger 23 decreases, and the refrigerant quantities
in other portions tend to be maintained substantially constant.
Consequently, when there is a refrigerant leak from the refrigerant
circuit 10, the total calculated refrigerant quantity M calculated
in the above described Step S32 is smaller than the total charged
refrigerant quantity Mt that is the refrigerant quantity in the
entire refrigerant circuit 10 immediately after the automatic
refrigerant charging operation is completed and that serves as a
reference refrigerant quantity for judging whether or not there is
a refrigerant leak; whereas when there is no refrigerant leak from
the refrigerant circuit 10, the total calculated refrigerant
quantity M has substantially the same value as the total charged
refrigerant quantity Mt.
[0134] By utilizing the above described characteristics, whether or
not there is a refrigerant leak is judged in Step S33. When it is
judged in Step S33 that there is no refrigerant leak from the
refrigerant circuit 10, the refrigerant leak detection operation
mode is finished.
[0135] On the other hand, when it is judged in Step S33 that there
is a refrigerant leak from the refrigerant circuit 10, the process
proceeds to Step S34, and a warning indicating that a refrigerant
leak is detected is displayed on the display 9b. Subsequently, the
refrigerant leak detection operation mode is finished.
[0136] In this way, the process from Steps S32 to S34 is performed
by the controller 8 that functions as the refrigerant leak
detection means, which is one of the refrigerant quantity judging
means, and which detects whether or not there is a refrigerant leak
by judging the adequacy of the refrigerant quantity in the
refrigerant circuit 10 during performing the refrigerant quantity
judging operation in the refrigerant leak detection operation
mode.
[0137] As described above, in the air conditioner 1 in the present
embodiment, the controller 8 functions as the refrigerant quantity
judging operation means, the refrigerant quantity calculating
means, the refrigerant quantity judging means, and the pipe volume
calculating means, and thereby configures the refrigerant quantity
judging system for judging the adequacy of the refrigerant quantity
charged into the refrigerant circuit 10.
(3) Characteristics of the Air Conditioner
[0138] The air conditioner 1 in the present embodiment has the
following characteristics.
[0139] (A)
[0140] In the air conditioner 1 of the present embodiment, the
volume of each of the refrigerant communication pipes 6 and 7 is
calculated based on the additional charging quantity Ma that is the
refrigerant quantity to be additionally charged after the
refrigerant circuit 10 is configured by the interconnection of the
outdoor unit 2 and the indoor units 4 and 5 via the refrigerant
communication pipes 6 and 7. Thus, even if the volumes of the
refrigerant communication pipes 6 and 7 are unknown, it is possible
to calculate the volumes of the refrigerant communication pipes 6
and 7 by inputting a value of the additional charging quantity Ma.
Accordingly, it is possible to determine the volume of each of the
refrigerant communication pipes 6 and 7 while minimizing the labor
of inputting information on the refrigerant communication pipes 6
and 7. As a result, it is possible to judge the adequacy of the
refrigerant quantity in the refrigerant circuit 10 with high
accuracy. More specifically, it is possible to judge whether or not
there is a refrigerant leak from the refrigerant circuit 10 with
high accuracy.
[0141] (B)
[0142] In the air conditioner 1 of the present embodiment, the
automatic refrigerant charging operation can be performed in which
whether or not the target charging quantity Ms is reached is judged
based on the operation state quantity of constituent equipment or
refrigerant flowing in the refrigerant circuit 10, so that it is
possible to reliably perform additional refrigerant charging, and
at the same time, it is possible to determine a value of the
additional charging quantity Ma required for the calculation of the
volumes of the refrigerant communication pipes 6 and 7 by
performing the automatic refrigerant charging operation.
[0143] (C)
[0144] In the air conditioner 1 of the present embodiment, it is
possible to calculate the communication pipe refrigerant quantity
Mp that is present with high accuracy during the automatic
refrigerant charging operation by subtracting the inside-unit
refrigerant quantity Mu calculated based on the operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit 10 in the automatic refrigerant charging
operation from the total charged refrigerant quantity Mt determined
by adding the additional charging quantity Ma to the initial
charging quantity Mi that is the refrigerant quantity that has been
charged in the refrigerant circuit 10 before the automatic
refrigerant charging operation. Thus, the volumes of the
refrigerant communication pipes 6 and 7 can be calculated with high
accuracy. In addition, in the air conditioner 1 of the present
embodiment, it is possible to easily calculate both the volume V1p
of the liquid refrigerant communication pipe 6 and the volume Vgp
of the gas refrigerant communication pipe 7 by predetermining the
volume ratio Rv between the liquid refrigerant communication pipe 6
and the gas refrigerant communication pipe 7 as a value
corresponding to the capacities and models of the indoor units 4, 5
and the outdoor unit 2.
(4) Alternative Embodiment
[0145] In the above described embodiment, the communication pipe
refrigerant quantity Mp required for the calculation of the volumes
of the refrigerant communication pipes 6 and 7 is determined by
calculating the inside-unit refrigerant quantity Mu determined by
the calculation above from the operation state quantity of
constituent equipment or refrigerant flowing in the refrigerant
circuit 10 in the automatic refrigerant charging operation and
subtracting the inside-unit refrigerant quantity Mu from the total
charged refrigerant quantity Mt. However, the refrigerant whose
quantity is substantially equal to the inside-unit refrigerant
quantity Mu that is present when the refrigerant quantity in the
refrigerant circuit 10 is reached the target charging quantity Ms
by the automatic refrigerant charging operation may be charged as
the initial charging quantity Mi into the refrigerant circuit 10
before the automatic refrigerant charging operation (in other
words, into the indoor units 4, 5 and the outdoor unit 2 to be
shipped to the installation site) is performed.
[0146] In this case, although a slight error will be generated
depending on the capacities and models of the indoor units 4 and 5
or the number of units and the like, the additional charging
quantity Ma that is the refrigerant quantity to be additionally
charged into the refrigerant circuit 10 in the automatic
refrigerant charging operation can be regarded as being
corresponding to the communication pipe refrigerant quantity Mp
that is refrigerant quantity present in the refrigerant
communication pipes 6 and 7. Therefore, unlike the above described
embodiment, the need to calculate the communication pipe
refrigerant quantity Mp using the inside-unit refrigerant quantity
Mu and the total charged refrigerant quantity Mt will be
eliminated, and thus the volumes of the refrigerant communication
pipes 6 and 7 can be easily calculated.
[0147] Meanwhile, even if the refrigerant whose quantity is
different from the refrigerant quantity corresponding to the
inside-unit refrigerant quantity Mu that is present when the
refrigerant quantity in the refrigerant circuit 10 is reached the
target charging quantity Ms by the automatic refrigerant charging
operation is charged as the initial charging quantity Mi in the
refrigerant circuit 10 before the automatic refrigerant charging
operation (in other words, into the indoor units 4 and 5 and the
outdoor unit 2 to be shipped to the installation site), in the
above described embodiment, as described above, the inside-unit
refrigerant quantity Mu is calculated from the operation state
quantity of constituent equipment or refrigerant flowing in the
refrigerant circuit 10 in the automatic refrigerant charging
operation. Therefore, even under various conditions of the initial
charging quantity Mi, it is possible to determine a correct value
of the communication pipe refrigerant quantity Mp, and it is
possible to calculate the volumes of the refrigerant communication
pipes 6 and 7 with high accuracy.
(5) Other Embodiment
[0148] While a preferred embodiment of the present invention has
been described with reference to the figures, the scope of the
present invention is not limited to the above embodiment, and the
various changes and modifications may be made without departing
from the scope of the present invention.
[0149] For example, in the above described embodiment, an example
in which the present invention is applied to an air conditioner
capable of switching and performing the cooling operation and
heating operation is described. However, it is not limited thereto,
and the present invention may be applied to different types of air
conditioners such as a cooling only air conditioner and the like.
In addition, in the above described embodiment, an example in which
the present invention is applied to an air conditioner including a
single outdoor unit is described. However, it is not limited
thereto, and the present invention may be applied to an air
conditioner including a plurality of outdoor units.
INDUSTRIAL APPLICABILITY
[0150] When the present invention is used, the labor of inputting
information on the refrigerant communication pipe before the
operation of a separate type air conditioner is minimized, and at
the same time, the adequacy of the refrigerant quantity in the
refrigerant circuit can be judged with high accuracy.
* * * * *