U.S. patent application number 10/585575 was filed with the patent office on 2008-11-20 for refrigerating apparatus.
This patent application is currently assigned to Daikin Industries, LTD.. Invention is credited to Azuma Kondo, Masaaki Takegami, Kenji Tanimoto.
Application Number | 20080282728 10/585575 |
Document ID | / |
Family ID | 35787217 |
Filed Date | 2008-11-20 |
United States Patent
Application |
20080282728 |
Kind Code |
A1 |
Takegami; Masaaki ; et
al. |
November 20, 2008 |
Refrigerating Apparatus
Abstract
In order that an indoor heat exchanger (41), a cold storage heat
exchanger (45), and a freeze storage heat exchanger (51) may differ
in their refrigerant evaporating temperature, a refrigerant circuit
(1E) is provided with a suction side three way switching valve
(102) capable of switching of flow paths between the heat
exchangers (41, 45, 51) and a compressor (2).
Inventors: |
Takegami; Masaaki; (Osaka,
JP) ; Tanimoto; Kenji; (Osaka, JP) ; Kondo;
Azuma; (Osaka, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
Daikin Industries, LTD.
Osaka-shi
JP
|
Family ID: |
35787217 |
Appl. No.: |
10/585575 |
Filed: |
August 4, 2005 |
PCT Filed: |
August 4, 2005 |
PCT NO: |
PCT/JP2005/014329 |
371 Date: |
July 10, 2006 |
Current U.S.
Class: |
62/498 ; 62/335;
62/440; 62/513 |
Current CPC
Class: |
F25B 13/00 20130101;
F25B 2313/02331 20130101; F25B 2313/0314 20130101; F25B 5/02
20130101; F25B 2600/021 20130101; Y02B 30/70 20130101; F25B 1/10
20130101; F25B 2400/22 20130101; F25B 2700/1933 20130101; F25B
2600/2507 20130101; F25B 2700/21152 20130101; F25B 2700/2104
20130101; Y02B 30/741 20130101; F25B 2700/21151 20130101; F25B
2400/13 20130101; F25B 2313/0231 20130101 |
Class at
Publication: |
62/498 ; 62/440;
62/513; 62/335 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F25D 11/00 20060101 F25D011/00; F25B 41/00 20060101
F25B041/00; F25B 7/00 20060101 F25B007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 6, 2004 |
JP |
2004-230604 |
Claims
1. A refrigerating apparatus comprising a refrigerant circuit (1E),
the refrigerant circuit (1E) including a compressor (2), a heat
source side heat exchanger (4), an expansion mechanism, a first
heat exchanger (41) for room air conditioning, and a second heat
exchanger (45, 51) for storage compartment refrigeration which are
connected, wherein: the refrigerant circuit (1E) is provided with
flow rate regulating means (102) for establishing switching of flow
paths between the first heat exchanger (41) and the second heat
exchanger (45, 51), and the compressor (2) in such a manner that
the amount of refrigerant flow becomes variable, whereby the first
heat exchanger (41) and the second heat exchanger (45, 51) differ
from each other in refrigerant evaporating temperature.
2. A refrigerating apparatus comprising a refrigerant circuit (1E),
the refrigerant circuit (1E) including a compressor (2), a heat
source side heat exchanger (4), an expansion mechanism, a first
heat exchanger (41) with a first evaporating temperature, and a
second heat exchanger (45, 51) with a second evaporating
temperature which are connected, wherein: the refrigerant circuit
(1E), in which the first heat exchanger (41) and the second heat
exchanger (45, 51) are connected in parallel, is provided, on a
suction side of the compressor (2), with flow rate regulating means
(102) for variably changing the amount of refrigerant flow from the
first heat exchanger (41) and the second heat exchanger (45, 51) to
the compressor (2).
3. The refrigerating apparatus of claim 1 or claim 2 wherein the
flow rate regulating means is a switching valve (102) capable of
flow rate regulation and connected to a suction pipe (6) of the
compressor (2) and to the first heat exchanger (41) and the second
heat exchanger (45, 51).
Description
TECHNICAL FIELD
[0001] The present invention relates generally to a refrigerating
apparatus, and more particularly, to a refrigerating apparatus
including an air conditioning heat exchanger for room air
conditioning and a refrigeration heat exchanger for storage
compartment refrigeration.
BACKGROUND ART
[0002] Refrigerating apparatuses which perform refrigeration cycles
are well known in the conventional art. This type of refrigerating
apparatus has been used widely as an air conditioner for providing
room air conditioning (cooling and heating) or as a cooler for a
refrigerator for storage of foods and the like. There is one such
refrigerating apparatus capable of both air conditioning and cold
storage. The refrigerating apparatus is equipped with a plurality
of utilization side heat exchangers including an air conditioning
heat exchanger and a refrigeration heat exchanger, and intended for
installation in a convenience store or the like. As disclosed in JP
Pat. No. 3253283 and JP, 2003-75022, A, just by installation of a
single refrigerating apparatus of this type, both store air
conditioning and showcase refrigeration can be provided.
[0003] The above-described conventional refrigerating apparatus is
equipped with a plurality of compressors, and by creating a
difference in evaporating pressure between a compressor which feeds
refrigerant to the air conditioning heat exchanger and another
compressor which feeds refrigerant to the refrigeration heat
exchanger, the refrigerant in the air conditioning heat exchanger
and the refrigerant in the refrigeration heat exchanger evaporate
at different temperatures. In this way, it becomes possible to
provide, by flow path switching, various operating modes (including
an operating mode in which only air conditioning is provided, an
operating mode in which only cold storage is provided, and an
operating mode in which air conditioning and cold storage are
provided in combination).
PROBLEMS THAT THE INVENTION INTENDS TO SOLVE
[0004] If the above-described conventional refrigerating apparatus
is provided, on the gas side of the air conditioning heat
exchanger, with an evaporating pressure regulating valve, this
allows the apparatus to accomplish switching of the operating modes
by constantly holding the evaporating pressure in the air
conditioning heat exchanger above a certain set value so that the
refrigerant in the air conditioning heat exchanger and the
refrigerant in the refrigeration heat exchanger have different
evaporating temperatures, without the need to create a difference
in evaporating pressure between the separate compressors. This
therefore makes it possible to achieve simplification of the
refrigerant circuit.
[0005] However, the separate provision of the evaporating pressure
regulating valve on the gas side of the air conditioning heat
exchanger produces problems, in other words the number of component
parts increases; the cost of production increases; and the loss of
pressure increases.
[0006] With these problems in mind, the present invention was
devised. Accordingly, an object of the present invention is to
provide efficient operating mode switching. To this end, the
difference in evaporating pressure between an air conditioning heat
exchanger and a refrigeration heat exchanger is made variable by
the use of a simplified configuration.
DISCLOSURE OF THE INVENTION
[0007] In the following, the present invention provides means for
solving the problems.
[0008] More specifically, a first problem solving means of the
invention provides a refrigerating apparatus comprising a
refrigerant circuit (1E), and the refrigerant circuit (1E) includes
a compressor (2), a heat source side heat exchanger (4), an
expansion mechanism, a first heat exchanger (41) for room air
conditioning, and a second heat exchanger (45, 51) for storage
compartment refrigeration which are connected.
[0009] The refrigerant circuit (1E) is provided with a flow rate
regulating means (102) for establishing switching of flow paths
between the first heat exchanger (41) and the second heat exchanger
(45, 51), and the compressor (2) in such a manner that the amount
of refrigerant flow becomes variable, whereby the first heat
exchanger (41) and the second heat exchanger (45, 51) differ from
each other in refrigerant evaporating temperature.
[0010] In the first problem solving means, while the evaporating
temperature of the first heat exchanger (41) is held higher than
that of the second heat exchanger (45, 51) by the flow rate
regulating means (102), flow path switching is established to
thereby accomplish operating mode switching.
[0011] A second problem solving means of the invention provides a
refrigerating apparatus comprising a refrigerant circuit (1E), and
the refrigerant circuit (1E) includes a compressor (2), a heat
source side heat exchanger (4), an expansion mechanism, a first
heat exchanger (41) with a first evaporating temperature, and a
second heat exchanger (45, 51) with a second evaporating
temperature which are connected.
[0012] The refrigerant circuit (1E), in which the first heat
exchanger (41) and the second heat exchanger (45, 51) are connected
in parallel, is provided, on a suction side of the compressor (2),
with a flow rate regulating means (102) for variably changing the
amount of refrigerant flow from the first heat exchanger (41) and
the second heat exchanger (45, 51) to the compressor (2).
[0013] In the second problem solving means, the flow rate
regulating means (102) arranged on the suction side of the
compressor (2) changes the amount of refrigerant flow so that the
first heat exchanger (41) and the second heat exchanger (45, 51)
which are connected in parallel differ from each other in
refrigerant evaporating temperature, thereby accomplishing
switching between operating modes.
[0014] A third problem solving means according to the first problem
solving means or the second problem solving means is characterized
in that the flow rate regulating means is a switching valve (102)
capable of flow rate regulation and connected to a suction pipe (6)
of the compressor (2) and to the first heat exchanger (41) and the
second heat exchanger (45, 51).
[0015] In the refrigerating apparatus of the third problem solving
means, the switching valve (102) operates to switch flow paths
while maintaining the difference in evaporating temperature between
the first heat exchanger (41) and the second heat exchanger (45,
51), thereby making it possible to perform each operating mode.
EFFECTS
[0016] Therefore, in accordance with these problem solving means of
the present invention, by means of the flow rate regulating means
(102), flow path switching is accomplished while the evaporating
temperature of the first heat exchanger (41) is held higher than
the evaporating temperature of the second heat exchanger (45, 51).
This arrangement therefore allows the refrigerating apparatus to
accomplish efficient switching between operating modes, without
having to create a difference in evaporating pressure by employing
a plurality of compressors or to separately provide a pressure
regulating valve.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a circuit diagram which illustrates a refrigerant
circuit of a refrigerating apparatus in accordance with an
embodiment of the present invention;
[0018] FIG. 2 is a refrigerant circuit diagram which depicts
refrigerant flow during the cooling operating mode;
[0019] FIG. 3 is a refrigerant circuit diagram which depicts
refrigerant flow during the refrigeration operating mode;
[0020] FIG. 4 is a refrigerant circuit diagram which depicts
refrigerant flow during cooling/refrigeration operating mode;
[0021] FIG. 5 is a Mollier chart which represents the behavior of
refrigerant in the cooling/refrigeration operating mode;
[0022] FIG. 6 is a refrigerant circuit diagram which depicts
refrigerant flow during the heating operating mode;
[0023] FIG. 7 is a refrigerant circuit diagram which depicts
refrigerant flow during a first heating/refrigeration operating
mode;
[0024] FIG. 8 is a refrigerant circuit diagram which depicts
refrigerant flow during a second heating/refrigeration operating
mode;
[0025] FIG. 9 is a refrigerant circuit diagram which depicts
refrigerant flow during a third heating/refrigeration operating
mode; and
[0026] FIG. 10 is a Mollier chart which represents the behavior of
refrigerant in the third heating/refrigeration operating mode.
BEST MODE FOR CARRYING OUT THE INVENTION
[0027] Hereinafter, an embodiment of the present invention is
described in detail by making reference to the drawing figures. The
following embodiment is an essentially preferable example, it
therefore being understood that the embodiment is not intended to
limit the scope of the present invention and its applicability.
[0028] With reference to FIG. 1, there is shown a refrigerating
apparatus (1) of the present embodiment which is generally
installed in premises such as a convenience store, a super market,
et cetera. The refrigerating apparatus (1) is employed to provide
both refrigeration of showcases (not shown), i.e. storage
compartment refrigeration, and room air cooling and heating.
[0029] The refrigerating apparatus (1) includes an outdoor unit
(1A), an indoor unit (1B), a cold storage unit (1C), and a freeze
storage unit (1D), and is equipped with a refrigerant circuit (1E)
which effects a vapor compression refrigeration cycle.
Additionally, the refrigerant circuit (1E) has a booster unit (1F).
The indoor unit (1B), the cold storage unit (1C), and the freeze
storage unit (1D) are connected in parallel. And the refrigerant
circuit (1E) is configured, such that it is selectively switchable
between a cooling cycle and a heating cycle.
[0030] The indoor unit (1B) is configured so as to be able to
selectively perform a cooling operating mode or a heating operating
mode. The indoor unit (1B) is installed for example on a store's
selling floor or other area. The cold storage unit (1C) is
installed in a cold storage showcase for cooling compartment air in
the cold storage showcase. The freeze storage unit (1D) is
installed in a freezer showcase for cooling compartment air in the
freezing showcase.
Outdoor Unit
[0031] The outdoor unit (1A) includes an inverter compressor (2), a
four way switching valve (3A), a discharge side three way switching
valve (101), a suction side switching valve (102) serving as a flow
rate regulating means, an outdoor heat exchanger (4) servings as a
heat source side heat exchanger, and an economizer heat exchanger
(103).
[0032] The inverter compressor (2) is made up of, for example, a
hermetically closed type screw compressor. The inverter compressor
(2) is configured, such that it is inverter controlled to gradually
or continuously vary in volume. The inverter compressor (2) has a
discharge pipe (5) in fluid communication with a first port of the
discharge side three way switching valve (101). The operating
volume of the inverter compressor (2) is controlled so that the
refrigerant pressure on the indoor unit's (1B) side is always held
constant. During the heat recovery operating mode in which an
indoor heat exchanger (41) and an outdoor heat exchanger (4) (which
are described later) each operate as a condenser, it is controlled
such that the pressure in the indoor heat exchanger (41) is held
constant. The inverter compressor (2) may be implemented by a
scroll compressor.
[0033] A gas side end of the outdoor heat exchanger (4) (i.e. the
end on the side of the inverter compressor (2)) is connected, by an
outdoor gas pipe (9), to the junction of a line extending from a
second port of the discharge side three way switching valve (101)
and a line extending from a second port of the four way switching
valve (3A). A heating electronic expansion valve (104) is
positioned at a liquid side end of the outdoor heat exchanger (4),
and one end of a first liquid pipe (10a) which is a liquid line and
one end of a second liquid pipe (10b) are connected in fluid
communication with the heating electronic expansion valve (104).
The heating electronic expansion valve (104) is employed to reduce
refrigerant pressure during the heating operating mode in which the
outdoor heat exchanger (4) operates as an evaporator. Its control
is exercised based on a suction heating temperature of the inverter
compressor (2) detected by a suction temperature sensor (67) (which
is described later). The first liquid pipe (10a) is connected in
fluid communication with an inlet opening of a receiver (14). A
first flow path (105) of the economizer heat exchanger (103) is
connected in fluid communication with the second liquid pipe
(10b).
[0034] The outdoor heat exchanger (4) is, for example, a fin and
tube heat exchanger of the cross fin type. An outdoor fan (4F) is
positioned in close proximity to the outdoor heat exchanger
(4).
[0035] The inverter compressor (2) has a suction pipe (6) connected
in fluid communication with a first port of the suction side three
way switching valve (102). A third port of the suction side three
way switching valve (102) is connected in fluid communication by
way of a closing valve (20) with a low pressure gas pipe (15).
[0036] A first port of the four way switching valve (3A) is
connected in fluid communication with the junction of a line
extending from a third port of the discharge side three way
switching valve (101) and a communicating pipe (21) (described
later). A line extending from a third port of the four way
switching valve (3A) is connected in fluid communication with a
second port of the suction side three way switching valve (102). An
interconnecting gas pipe (17) is connected in fluid communication
by way of a closing valve (20) with a line extending from a fourth
port of the four way switching valve (3A).
[0037] The four way switching valve (3A) is configured, such that
it selectively changes state between an ON state (indicated by
solid line of FIG. 2) and an OFF state (indicated by broken line of
FIG. 2). The ON state allows fluid communication between the
junction of the line extending from the third port of the discharge
side three way switching valve (101) and the communicating pipe
(21), and the interconnecting gas pipe (17) and, in addition,
allows fluid communication between the junction of the outdoor gas
pipe (9) and the line extending from the second port of the
discharge side three way switching valve (101), and a line
extending from the second port of the suction side three way
switching valve (102), while on the other hand the OFF state allows
fluid communication between the junction of the line extending from
the third port of the discharge side three way switching valve
(101) and the communicating pipe (21), and the outdoor gas pipe (9)
and, in addition, allows fluid communication between the
interconnecting gas pipe (17) and the line extending from the
second port of the suction side three way switching valve
(102).
[0038] The interconnecting gas pipe (17), the low pressure gas pipe
(15), and the connecting liquid pipe (19) are arranged so as to
extend outwardly from the outdoor unit (1A), and their respective
closing valves (20) are located within the outdoor unit (1A).
[0039] The economizer heat exchanger (103) is provided with a first
flow path (105) and a second flow path (106). A line extending from
one end of the first flow path (105) is connected in fluid
communication with the outlet opening of the receiver (14). The
other end of the first flow path (105) is connected in fluid
communication with the junction of the connecting liquid pipe (19)
and a line extending from the inlet-opening of the receiver (14).
One end of the second flow path (106) is connected in fluid
communication by way of a check valve (7) with an intermediate
pressure part (not shown) of the inverter compressor (2). The other
end of the second flow path (106) is connected in fluid
communication by way of an economizer electronic expansion valve
(107) with the junction of the line extending towards the
connecting liquid pipe (19) from the inlet opening of the receiver
(14). As a result of this configuration, liquid refrigerant exiting
from the outlet opening of the receiver (14) once passes through
the first flow path (105) of the economizer heat exchanger (103).
Subsequently, the refrigerant is reduced in pressure in the
economizer electronic expansion valve (107). Then, the refrigerant
passes through the second flow path (106), during which the
refrigerant, which is in a low pressure state, is supercooled by
refrigerant in the first flow path (105), and is introduced into
the intermediate pressure part of the inverter compressor (2). The
economizer electronic expansion valve (107) is controlled in
accordance with the supercooling degree and the temperature of
refrigerant in the discharge pipe (5) of the inverter compressor
(2). The check valve (7) is employed to prevent refrigerant back
flow from the intermediate pressure part of the inverter compressor
(2). By introduction of the supercooled, low pressure refrigerant
into to the intermediate pressure part of the inverter compressor
(2), the inverter compressor (2) is prevented from being
overheated.
[0040] Check valves (7) are provided, respectively, on the side of
the first liquid pipe (10a) and on the side of the first flow path
(105) of the economizer heat exchanger (103) in the inlet opening
of the receiver (14), whereby refrigerant flows only in the
direction of the inlet opening of the receiver (14). In addition, a
condensing pressure regulating valve (108) is located between the
line extending from the inlet opening of the receiver (14) and the
side of the first flow path (105) of the economizer heat exchanger
(103). The condensing pressure regulating valve (108) is employed
to prevent a refrigerant deficiency on the side of the indoor unit
(1B) when outside temperature is low during the heating operating
mode.
[0041] The communicating pipe (21) which is an auxiliary line is
fluidly connected between the junction of the line extending from
the first port of the four way switching valve (3A) and the line
extending from the third port of the discharge side three way
switching valve (101), and the line extending towards the receiver
(14) from the connecting liquid pipe (19). The communicating pipe
(21) is provided with a spring-loaded check valve (109). The
spring-loaded check valve (109) is configured not to operate under
normal conditions, but it is employed to prevent fluid leak from
occurring when the receiver (14) is filled up with liquid
refrigerant at shutdown or when each valve is placed in the closed
state.
Indoor Unit
[0042] The indoor unit (1B) includes, in addition to the indoor
heat exchanger (41) which serves as a first heat exchanger, an
indoor expansion valve (42) which is an expansion mechanism. The
gas side of the indoor heat exchanger (41) is connected in fluid
communication with the interconnecting gas pipe (17). On the other
hand, the liquid side of the indoor heat exchanger (41) is
connected in fluid communication by way of the indoor expansion
valve (42) with a second interconnecting liquid pipe (12). The
second interconnecting liquid pipe (12) is connected in fluid
communication with the connecting liquid pipe (19) extending to the
outdoor unit (1A). The indoor heat exchanger (41) is, for example,
a fin and tube heat exchanger of the cross fin type. An indoor fan
(43) is positioned in close proximity to the indoor heat exchanger
(41).
Cold Storage Unit
[0043] The cold storage unit (1C) includes, in addition to the cold
storage heat exchanger (45) which serves as a second heat
exchanger, a cold storage expansion valve (46) which is an
expansion mechanism. The liquid side of the cold storage heat
exchanger (45) is connected in fluid communication by way of an
electromagnetic valve (7a) and the cold storage expansion valve
(46) with a first interconnecting liquid pipe (11). On the other
hand, the gas side of the cold storage heat exchanger (45) is
connected in fluid communication with the low pressure gas pipe
(15).
[0044] The cold storage heat exchanger (45) is in fluid
communication by way of the low pressure gas pipe (15) with the
third port of the suction side three way switching valve (102),
while during the cooling operating mode the indoor heat exchanger
(41) is in fluid communication by way of the interconnecting gas
pipe (17) with the second port of the suction side three way
switching valve (102). By virtue of the flow rate regulation of the
suction side three way switching valve (102), the refrigerant
pressure (evaporating pressure) of the cold storage heat exchanger
(45) falls below the refrigerant pressure (evaporating pressure) of
the indoor heat exchanger (41). As a result of this, the
refrigerant evaporating temperature of the cold storage heat
exchanger (45) becomes, for example, minus 10 degrees Centigrade,
while the refrigerant evaporating temperature of the indoor heat
exchanger (41) becomes, for example, plus 5 degrees Centigrade,
whereby the refrigerant circuit (1E) constitutes a circuit with
different evaporation temperatures.
[0045] The cold storage expansion valve (46) is a temperature
sensitive expansion valve and its temperature sensing tube is
provided on the gas side of the cold storage heat exchanger (45).
The cold storage heat exchanger (45) is, for example, a fin and
tube heat exchanger of the cross fin type. A cold storage fan (47)
is positioned in close proximity to the cold storage heat exchanger
(45).
Freeze Storage Unit
[0046] The freeze storage unit (1D) includes a freeze storage heat
exchanger (51) which serves as a second heat exchanger, and a
freeze storage expansion valve (52) which is an expansion
mechanism. The liquid side of the freeze storage heat exchanger
(51) is connected in fluid communication by way of an
electromagnetic valve (7b) and the freeze storage expansion valve
(52) with a branch liquid pipe (13) branched off from the first
interconnecting liquid pipe (11).
[0047] The freeze storage expansion valve (52) is a temperature
sensitive expansion valve and its temperature sensing tube is
provided on the gas side of the freeze storage heat exchanger (51).
The freeze storage heat exchanger (51) is, for example, a fin and
tube heat exchanger of the cross fin type. A freeze storage fan
(58) is positioned in close proximity to the freeze storage heat
exchanger (51).
Booster Unit
[0048] The booster unit (1F) includes a booster compressor (53) and
a supercooling heat exchanger (210).
[0049] In order that the evaporating temperature of refrigerant in
the freeze storage heat exchanger (51) may fall below the
evaporating temperature of refrigerant in the cold storage heat
exchanger (45), the booster compressor (53) two-stage compresses
refrigerant along with the inverter compressor (2). The refrigerant
evaporating temperature of the freeze storage heat exchanger (51)
is set at minus 40 degrees Centigrade for example.
[0050] The gas side of the freeze storage heat exchanger (51) and
the suction side of the booster compressor (53) are connected in
fluid communication with each other by a connecting gas pipe (54).
The discharge side of the booster compressor (53) is connected in
fluid communication with a branch gas pipe (16) branched off from
the low pressure gas pipe (15). The branch gas pipe (16) is
provided with a check valve (7) and an oil separator (55). An oil
return pipe (57) having a capillary tube is connected between the
oil separator (55) and the connecting gas pipe (54).
[0051] A bypass pipe (59) is connected between the connecting gas
pipe (54) which is the suction side of the booster compressor (53)
and the downstream side of the check valve (7) of the branch gas
pipe (16) which is the discharge side of the booster compressor
(53). The bypass pipe (59) is configured so that, when the booster
compressor (53) is at shutdown (for example when the booster
compressor (53) becomes out of order), refrigerant flow bypasses
the booster compressor (53).
[0052] The supercooling heat exchanger (210) is made up of a
so-called plate heat exchanger. A plurality of first flow paths
(211) and a plurality of second flow paths (212) are formed within
the supercooling heat exchanger (210). A third interconnecting
liquid pipe (18) branches off from the first interconnecting liquid
pipe (11). The first flow path (211) of the supercooling heat
exchanger (210) forms a part of the first interconnecting liquid
pipe (11), while the second flow path (212) forms a part of the
third interconnecting liquid pipe (18).
[0053] A supercooling expansion valve (223) is provided between the
branch point at which the third interconnecting liquid pipe (18)
branches off from the third interconnecting liquid pipe (18) and
the second flow path (212). The supercooling expansion valve (223)
is made up of a temperature sensitive expansion valve and its
temperature sensing tube is provided on the opposite side of the
second flow path (212).
[0054] The supercooling heat exchanger (210) is employed to effect
heat exchange between refrigerant flowing through the first flow
path (211) and refrigerant of the refrigerating apparatus (10)
flowing through the second flow path (212), when the supercooling
expansion valve (223) is placed in the open state. The refrigerant,
cooled as a result of passage through the first flow path (211), is
passed through the first interconnecting liquid pipe (11) and then
flows through the cold storage and freeze storage heat exchangers
(45, 51).
Control System
[0055] The refrigerant circuit (1E) is provided with various
sensors and various switches. A high pressure sensor (61) for
detecting the pressure of high pressure refrigerant is provided in
the vicinity of the third port of the discharge side three way
switching valve (101) of the outdoor unit (1A). The inverter
compressor (2) is provided with a discharge temperature sensor (62)
for detecting the temperature of high pressure refrigerant.
[0056] Low pressure sensors (65, 66) for detecting the pressure of
low pressure refrigerant and a suction temperature sensor (67) for
detecting the temperature of low pressure refrigerant are provided
in the vicinity of the suction pipe (6) of the inverter compressor
(2).
[0057] Additionally, the outdoor unit (1A) is provided with an
outside air temperature sensor (70) for detecting the temperature
of outside air.
[0058] The indoor heat exchanger (41) is provided with an indoor
heat exchange sensor (71) for detecting the temperature of
condensation or evaporation, i.e. the temperature of refrigerant,
in the indoor heat exchanger (41), and a gas temperature sensor
(72) for detecting the temperature of gas refrigerant is provided
on the gas side thereof. In addition, the indoor unit (1B) is
provided with a room temperature sensor (73) for detecting the
temperature of room air.
[0059] The cold storage unit (1C) is provided with a cold storage
temperature sensor (74) for detecting the compartment temperature
of a cold storage showcase. The freeze storage unit (1D) is
provided with a freeze storage temperature sensor (75) for
detecting the compartment temperature of a freeze storage
showcase.
[0060] Output signals from the various sensors and switches are fed
to a controller (80) (shown only in FIG. 1). The controller (80) is
configured, such that it controls the volume of the inverter
compressor (2), and so on.
[0061] In addition, the controller (80) is configured, such that it
controls the operation of the refrigerant circuit (1E) to
selectively switch to a cooling operating mode, a refrigeration
operating mode, a cooling/refrigeration operating mode, a heating
operating mode, a first heating/refrigeration operating mode, a
second heating/refrigeration operating mode, or a third
heating/refrigeration operating mode.
[0062] By control by the controller (80), the second port of the
discharge side three way switching valve (101) is fully closed when
the outdoor heat exchanger (4) becomes an evaporator, as a result
of which all of the refrigerant is forced to flow towards the third
port of the discharge side three way switching valve (101). On the
other hand, when the indoor heat exchanger (41) becomes a condenser
during the heating operating mode and at thermo off, the third port
is fully closed, as a result of which all of the refrigerant is
forced to flow towards the second port. In addition, during the
heat recovery operating mode wherein the indoor heat exchanger (41)
and the outdoor heat exchanger (4) each operate as a condenser, it
is controlled such that the second port is placed in the open state
so that the discharge pressure falls below a certain level, when
the high pressure sensor (61) detects that the discharge pressure
of the inverter compressor (2) exceeds a certain level.
[0063] By control by the controller (80), the third port of the
suction side three way switching valve (102) is constantly placed
in the closed state when only the indoor unit (1B) is operated.
Running Operation
[0064] In the following, main running operations that the
refrigerating apparatus (1) performs will now be described.
Cooling Mode
[0065] The cooling mode selectively switches to any one of the
cooling operating mode, the refrigeration operating mode, and the
cooling/refrigeration operating mode.
Cooling Operating Mode
[0066] As illustrated in FIG. 2, this cooling operating mode is an
operating mode which provides only cooling by the indoor unit
(1B).
[0067] The four way switching valve (3A), as indicated by solid
line of FIG. 2, changes state to the OFF state. The electromagnetic
valve (7a) of the cold storage unit (1C) and the electromagnetic
valve (7b) of the freeze storage unit (1D) are placed in the closed
state.
[0068] In this state, refrigerant expelled out of the inverter
compressor (2) is passed through the second port of the discharge
side three way switching valve (101) and is then distributed
towards the outdoor gas pipe (9). Subsequently, the refrigerant
condenses in the outdoor heat exchanger (4). This liquid
refrigerant resulting from condensation flows through the first
liquid pipe (10a), enters the receiver (14), passes through the
connecting liquid pipe (19) and then through the second
interconnecting liquid pipe (12), flows into the indoor heat
exchanger (41) by way of the indoor expansion valve (42), and is
evaporated in the indoor heat exchanger (41). The gas refrigerant
resulting from evaporation flows through the interconnecting gas
pipe (17) and then through the four way switching valve (3A),
passes through the second port of the suction side three way
switching valve (102), and returns into the inverter compressor
(2). This circulation is repeatedly performed to thereby effect
room air cooling, i.e. cooling of the inside of the store.
[0069] The degree of opening of the indoor expansion valve (42) is
superheating degree controlled based on the temperature detected by
the indoor heat exchange sensor (71) and the gas temperature sensor
(72), which is applied in the same way in the following cooling
modes.
Refrigeration Operating Mode
[0070] This refrigeration operating mode is an operating mode which
provides only refrigeration by the cold storage unit (1C) and
refrigeration by the freeze storage unit (1D).
[0071] The four way switching valve (3A), as indicated by solid
line of FIG. 3, changes state to the OFF state. In addition, the
electromagnetic valve (7a) of the cold storage unit (1C) and the
electromagnetic valve (7b) of the freeze storage unit (1D) are
placed in the open state, while the indoor expansion valve (42) is
placed in the closed state.
[0072] In this state, refrigerant expelled out of the inverter
compressor (2) is passed through the second port of the discharge
side three way switching valve (101) and is distributed towards the
outdoor gas pipe (9). Subsequently, the refrigerant condenses in
the outdoor heat exchanger (4). This liquid refrigerant resulting
from condensation flows through the first liquid pipe (10a), enters
the receiver (14), and passes through the connecting liquid pipe
(19) and then through the first interconnecting liquid pipe (11),
and one part of the refrigerant flows into the cold storage heat
exchanger (45) by way of the cold storage expansion valve (46) and
is evaporated in the cold storage heat exchanger (45).
[0073] On the other hand, the other part of the liquid refrigerant
flowing through the first interconnecting liquid pipe (11) flows
through the branch liquid pipe (13), flows into the freeze storage
heat exchanger (51) by way of the freeze storage expansion valve
(52), and is evaporated in the freeze storage heat exchanger (51).
This gas refrigerant resulting from evaporation in the freeze
storage heat exchanger (51) is drawn into the booster compressor
(53), is compressed there, and is then discharged to the branch gas
pipe (16).
[0074] The gas refrigerant resulting from evaporation in the cold
storage heat exchanger (45) and the gas refrigerant expelled out of
the booster compressor (53) join together in the low pressure gas
pipe (15), and the merged refrigerant returns, via the third port
of the suction side three way switching valve (102), into the
inverter compressor (2). This circulation is repeatedly performed
to thereby effect storage compartment refrigeration, i.e.
refrigeration of the cold storage showcase and refrigeration of the
freeze storage showcase.
[0075] The refrigerant in the freeze storage heat exchanger (51) is
drawn into the booster compressor (53), therefore being lower in
pressure than the refrigerant in the cold storage heat exchanger
(45). As a result of this, for example, the refrigerant temperature
(evaporating temperature) in the freeze storage heat exchanger (51)
becomes minus 40 degrees Centigrade, while the refrigerant
temperature (evaporating temperature) in the cold storage heat
exchanger (45) becomes minus 10 degrees Centigrade.
[0076] In addition, the degree of opening of the cold storage
expansion valve (46) and the degree of opening of the freeze
storage expansion valves (52) are superheating degree controlled by
the temperature sensing tubes, which is the same in each of the
following operating modes.
Cooling/Refrigeration Operating Mode
[0077] As illustrated in FIG. 4, this cooling/refrigeration
operating mode is an operating mode which provides cooling by the
indoor unit (1B), refrigeration by the cold storage unit (1C), and
refrigeration by the freeze storage unit (1D) at the same time.
[0078] In addition, as indicated by solid line of FIG. 4, the four
way switching valve (3A) changes state to the OFF state.
Furthermore, the indoor expansion valve (42), the electromagnetic
valve (7a) of the cold storage unit (1C), and the electromagnetic
valve (7b) of the freeze storage unit (1D) are all placed in the
open state.
[0079] In this state, refrigerant expelled out of the inverter
compressor (2) is passed through the second port of the discharge
side three way switching valve (101) and distributed towards the
outdoor gas pipe (9). Subsequently, the refrigerant condenses in
the outdoor heat exchanger (4). This liquid refrigerant resulting
from condensation flows through the first liquid pipe (10a), enters
the receiver (14), and passes through the connecting liquid pipe
(19), and its flow branches off into the first interconnecting
liquid pipe (11) and the second interconnecting liquid pipe
(12).
[0080] The liquid refrigerant flowing through the second
interconnecting liquid pipe (12) flows into the indoor heat
exchanger (41) by way of the indoor expansion valve (42) and is
evaporated in the indoor heat exchanger (41). This gas refrigerant
resulting from evaporation is reduced in pressure when passing
through the second port of the suction side three way switching
valve (102) via the four way switching valve (3A) from the
interconnecting gas pipe (17), and returns into the inverter
compressor (2).
[0081] On the other hand, one part of the liquid refrigerant
flowing through the first interconnecting liquid pipe (11) flows
into the cold storage heat exchanger (45) by way of the cold
storage expansion valve (46) and is evaporated in the cold storage
heat exchanger (45), and the other part of the liquid refrigerant
flowing through the first interconnecting liquid pipe (11) flows
through the branch liquid pipe (13), flows into the freeze storage
heat exchanger (51) by way of the freeze storage expansion valve
(52), and is evaporated in the freeze storage heat exchanger (51).
This gas refrigerant resulting from evaporation in the freeze
storage heat exchanger (51) is drawn into the booster compressor
(53), compressed there, and expelled to the branch gas pipe
(16).
[0082] The gas refrigerant as a result of evaporation in the cold
storage heat exchanger (45) and the gas refrigerant expelled out of
the booster compressor (53) join together in the low pressure gas
pipe (15), and the merged refrigerant returns, via the third port
of the suction side three way switching valve (102), into the
inverter compressor (2).
[0083] This circulation is repeatedly performed to thereby effect
room air cooling, i.e. cooling of the inside of the store,
simultaneously with storage compartment refrigeration, i.e.
refrigeration of the cold storage showcase and refrigeration of the
freeze storage showcase.
[0084] Here, by making reference to FIG. 5, the behavior of
refrigerant during the cooling/refrigeration operating mode is
described. However, for the sake of simplification, the description
of the action of supercooling in the economizer and supercooling
heat exchangers (103, 210) is omitted.
[0085] In the first place, refrigerant is compressed up to Point A
by the inverter compressor (2). The refrigerant at Point A
condenses to become a refrigerant at Point B. One part of the
refrigerant at Point B is reduced in pressure down to Point C by
the indoor expansion valve (42), evaporates at, for example, plus 5
degrees Centigrade, is reduced in pressure down to Point E when
passing through the second port of the suction side three way
switching valve (102) at Point D, and is then drawn into the
inverter compressor (2).
[0086] In addition, one part of the refrigerant at Point B is
reduced in pressure down to Point F by the cold storage expansion
valve (46), evaporates at, for example, minus 10 degrees
Centigrade, and is then drawn into the inverter compressor (2) at
Point E.
[0087] Additionally, one part of the refrigerant at Point B is
reduced in pressure down to Point G by the freeze storage expansion
valve (52) because it is drawn into the booster compressor (53),
evaporates at, for example, minus 40 degrees Centigrade, and is
then drawn into the booster compressor (53) at Point H. The
refrigerant compressed to Point I by the booster compressor (53) is
drawn into the inverter compressor (2) at Point E.
[0088] As described above, the refrigerant in the refrigerant
circuit (1E) evaporates at different temperatures by the suction
side three way switching valve (102). Besides, by two-stage
compression by the booster compressor (53), there are created three
different evaporation temperatures.
Heating Mode
[0089] The heating mode is selectively switched, by control
exercised by the controller (80), to either one of the heating
operating mode, the first heating/refrigeration operating mode, the
second heating/refrigeration operating mode, and the third
heating/refrigeration operating mode.
Heating Operating Mode
[0090] This heating operating mode is an operating mode which
provides only heating by the indoor unit (1B). The four way
switching valve (3A) changes state to the ON state, as indicated by
solid line of FIG. 6. The second port of the discharge side three
way switching valve (101) is placed in the closed state. The third
port of the suction side three way switching valve (102) is placed
in the closed state. In addition, the electromagnetic valve (7a) of
the cold storage unit (1C) and the electromagnetic valve (7b) of
the freeze storage unit (1D) are placed in the closed state.
[0091] In this state, refrigerant expelled out of the inverter
compressor (2) passes through the third port of the discharge side
three way switching valve (101), then through the four way
switching valve (3A), and then through the interconnecting gas pipe
(17) and flows into the indoor heat exchanger (41) where the
refrigerant condenses. This liquid refrigerant resulting from
condensation flows through the second interconnecting liquid pipe
(12) and enters the receiver (14). Subsequently, the liquid
refrigerant flows into the outdoor heat exchanger (4) by way of the
heating electronic expansion valve (104) and is evaporated in the
outdoor heat exchanger (4). The gas refrigerant resulting from
evaporation passes through the outdoor gas pipe (9), then through
the four way switching valve (3A), and then through the suction
side three way switching valve (102) and returns into the inverter
compressor (2). This circulation is repeatedly performed to thereby
effect room air heating, i.e. heating of the inside of the
store.
[0092] The degree of opening of the heating electronic expansion
valve (104) is superheating degree controlled depending on the
pressure corresponding saturation temperature based on the low
pressure sensors (65, 66) and on the temperature detected by the
suction temperature sensor (67). The degree of opening of the
indoor expansion valve (42) is supercooling degree controlled based
on the temperature detected by the indoor heat exchange sensor
(71). The controlling of the degree of opening of the heating
electronic expansion valve (104) and the controlling of the degree
of opening of the indoor expansion valve (42) are the same in the
following heating modes.
First Heating/Refrigeration Operating Mode
[0093] This first heating/refrigeration operating mode is an
operating mode which provides heating by the indoor unit (1B),
refrigeration by the cold storage unit (1C), and refrigeration by
the freeze storage unit (1D), without using the outdoor heat
exchanger (4).
[0094] The four way switching valve (3A) changes state to the ON
state, as indicated by solid line of FIG. 7. The second port of the
discharge side-three way switching valve (101) is placed in the
closed state, while the third port of the suction side three way
switching valve (102) is placed in the open state. Furthermore, the
electromagnetic valve (7a) of the cold storage unit (1C) and the
electromagnetic valve (7b) of the freeze storage unit (1D) are
placed in the open state, while on the other hand the heating
electronic expansion valve (104) is placed in the closed state.
[0095] In this state, all of the refrigerant expelled out of the
inverter compressor (2) is fed towards the third port of the
discharge side three way switching valve (101). This refrigerant
passes through the four way switching valve (3A) and then through
the interconnecting gas pipe (17) and flows into the indoor heat
exchanger (41) where the refrigerant condenses. The liquid
refrigerant resulting from condensation flows through the second
interconnecting liquid pipe (12) and then through the first
interconnecting liquid pipe (11).
[0096] One part of the liquid refrigerant flowing through the first
interconnecting liquid pipe (11) flows into the cold storage heat
exchanger (45) by way of the cold storage expansion valve (46) and
is evaporated in the cold storage heat exchanger (45). On the other
hand, the other part of the liquid refrigerant flowing through the
first interconnecting liquid pipe (11) flows through the branch
liquid pipe (13) into the freeze storage heat exchanger (51) by way
of the freeze storage expansion valve (52) and is evaporated in the
freeze storage heat exchanger (51). This gas refrigerant resulting
from evaporation in the freeze storage heat exchanger (51) is drawn
into the booster compressor (53), compressed there, and is then
expelled to the branch gas pipe (16).
[0097] The gas refrigerant resulting from evaporation in the cold
storage heat exchanger (45) and the gas refrigerant expelled out of
the booster compressor (53) join together in the low pressure gas
pipe (15), and the merged refrigerant returns into the inverter
compressor (2). This circulation is repeatedly performed to thereby
effect room air heating, i.e. heating of the inside of the store,
simultaneously with storage compartment refrigeration, i.e.
refrigeration of the cold storage showcase and refrigeration of the
freeze storage showcase. In other words, the refrigeration
capability of the cold storage and freeze storage units (1C, 1D),
i.e. the amount of evaporation heat, is in balance with the heating
capability of the indoor unit (1B), i.e. the amount of condensation
heat, whereby 100% heat recovery is achieved.
Second Heating/Refrigeration Operating Mode
[0098] As illustrated in FIG. 8, this second heating/refrigeration
operating mode is a heating capability excess operating mode in
which the heating capability of the indoor unit (1B) becomes
surplus during the first heating/refrigeration operating mode.
[0099] The second heating/refrigeration operating mode is a heat
recovery operating mode when the heating capability of the indoor
unit (1B) becomes surplus in the first heating/refrigeration
operating mode.
[0100] Upon detection by the high pressure sensor (61) that the
discharge pressure of the inverter compressor (2) exceeds a certain
level, the controller (80) controls the second port to open, and
refrigerant expelled out of the inverter compressor (2) is
distributed by the discharge side three way switching valve (101).
Stated another way, only refrigerant of a flow rate capable of
giving condensation heat necessary in the indoor heat exchanger
(41) is passed through the third port to the indoor heat exchanger
(41) where the refrigerant is condensed. The liquid refrigerant
resulting from condensation flows through the second
interconnecting liquid pipe (12) and then through the first
interconnecting liquid pipe (11).
[0101] On the other hand, the rest of the refrigerant expelled out
of the inverter compressor (2) passes through the second port of
the discharge side three way switching valve (101) and is then
distributed towards the outdoor gas pipe (9). Subsequently, the
refrigerant condenses in the outdoor heat exchanger (4). This
liquid refrigerant resulting from condensation flows through the
first liquid pipe (10a), enters the receiver (14), passes through
the connecting liquid pipe (19), and joins the refrigerant which
has passed through the indoor heat exchanger (41) in the first
interconnecting liquid pipe (11).
[0102] Thereafter, one part of the refrigerant flowing through the
first interconnecting liquid pipe (11) flows into the cold storage
heat exchanger (45) where the one part refrigerant is evaporated.
On the other hand, the other part of the refrigerant flowing
through the first interconnecting liquid pipe (11) flows into the
freeze storage heat exchanger (51) where the other part refrigerant
is evaporated. The gas refrigerant resulting from evaporation in
the cold storage heat exchanger (45) and the gas refrigerant
expelled out of the booster compressor (53) after evaporation in
the freeze storage heat exchanger (51) join together in the low
pressure gas pipe (15), and the merged gas refrigerant passes
through the third port of the suction side three way switching
valve (102) and returns into the inverter compressor (2). This
circulation is repeatedly performed to thereby effect room air
heating, i.e. heating of the inside of the store, simultaneously
with storage compartment refrigeration, i.e. refrigeration of the
cold storage showcase and refrigeration of the freeze storage
showcase. In other words, the refrigeration capability of the cold
storage and freeze storage units (1C, 1D), i.e. the amount of
evaporation heat, is out of balance with the heating capability of
the indoor unit (1B), i.e. the amount of condensation heat, and
only surplus condensation heat is released outdoors in the outdoor
heat exchanger (4).
Third Heating/Refrigeration Operating Mode
[0103] This third heating/refrigeration operating mode is a heating
capability deficiency operating mode in which the heating
capability of the indoor unit (1B) becomes deficient in the first
heating/refrigeration operating mode. In other words, this is an
operating mode which is deficient in the amount of evaporation
heat.
[0104] The four way switching valve (3A) changes state to the ON
state, as indicated by solid line of FIG. 9. The second port of the
discharge side three way switching valve (101) is placed in the
closed state, while the second and third ports of the suction side
three way switching valve (102) are placed in the open state.
Furthermore, the indoor expansion valve (42), the electromagnetic
valve (7a) of the cold storage unit (1C), and the electromagnetic
valve (7b) of the freeze storage unit (1D) are all placed in the
open state.
[0105] Accordingly, as in the first heating/refrigeration operating
mode, all of refrigerant expelled out of the inverter compressor
(2) flows into the indoor heat exchanger (41) where the refrigerant
is condensed. The liquid refrigerant resulting from condensation
passes through the second interconnecting liquid pipe (12) and
flows into the first interconnecting liquid pipe (11) and into the
receiver (14).
[0106] Thereafter, one part of the refrigerant flowing through the
first interconnecting liquid pipe (11) flows into the cold storage
heat exchanger (45) where the one part refrigerant is evaporated.
On the other hand, the other part of the refrigerant flowing
through the first interconnecting liquid pipe (11) flows into the
freeze storage heat exchanger (51) where the other part refrigerant
is evaporated. The gas refrigerant resulting from evaporation in
the cold storage heat exchanger (45) and the gas refrigerant
expelled out of the booster compressor (53) after evaporation in
the freeze storage heat exchanger (51) join together in the low
pressure gas pipe (15), and the merged gas refrigerant is reduced
in pressure when passing through the third port of the suction side
three way switching valve (102) and returns into the inverter
compressor (2).
[0107] On the other hand, the other liquid refrigerant which has
flowed into the side of the receiver (14) passes through the second
liquid pipe (10b) and then through the heating electronic expansion
valve (104), flows into the outdoor heat exchanger (4), and is
evaporated there. The gas refrigerant resulting from evaporation
flows through the outdoor gas pipe (9), passes through the four way
switching valve (3A) and then through the suction side three way
switching valve (102), and returns into the inverter compressor
(2).
[0108] This circulation is repeatedly performed to thereby effect
room air heating, i.e. heating of the inside of the store,
simultaneously with storage compartment refrigeration, i.e.
refrigeration of the cold storage showcase and refrigeration of the
freeze storage showcase. In other words, the refrigeration
capability of the cold storage and freeze storage units (1C, 1D),
i.e., the amount of evaporation heat, is out of balance with the
heating capability of the indoor unit (1B), i.e. the amount of
condensation heat, and the amount of evaporation heat which is
lacking is derived from the outdoor heat exchanger (4).
[0109] The behavior of refrigerant in the third
heating/refrigeration operating mode is therefore described with
reference to FIG. 10. However, for the sake of simplification, the
description of the action of supercooling in the economizer and
supercooling heat exchangers (103, 210) is omitted.
[0110] In the first place, refrigerant is compressed up to Point A
by the inverter compressor (2). The refrigerant at Point A is
condensed to become a refrigerant at Point B. This refrigerant at
Point B is reduced in pressure down to Point C by the heating
electronic expansion valve (104), is evaporated at, for example,
minus 15 degrees Centigrade, and is drawn into the inverter
compressor (2) at Point D.
[0111] In addition, one part of the refrigerant at Point B is
reduced in pressure down to Point E by the cold storage expansion
valve (46), is evaporated at, for example, minus 10 degrees
Centigrade, is reduced in pressure down to Point D when passing
through the third port of the suction side three way switching
valve (102) at Point F, and is drawn into the inverter compressor
(2).
[0112] In addition, one part of the refrigerant at Point B, since
it is drawn into the booster compressor (53), is reduced in
pressure down to Point G by the freeze storage expansion valve
(52), is evaporated at, for example, minus 40 degrees Centigrade,
and is drawn into the booster compressor (53) at Point H. The
refrigerant compressed up to Point I by the booster compressor (53)
is reduced in pressure down to Point D when passing through the
third port of the suction side three way switching valve (102) at
Point F, and is drawn into the inverter compressor (2).
[0113] As described above, the refrigerant in the refrigerant
circuit (1E) evaporates at different temperatures by the suction
side three way switching valve (102). Besides, by two-stage
compression by the booster compressor (53), there are created three
different evaporation temperatures.
Capability Regulating Techniques
[0114] In the following, how the capability to provide air
conditioning (the capability to provide cooling or heating) and the
capability to provide cold storage/freeze storage are regulated in
each of the operating modes is described.
[0115] The controller (80) controls the inverter compressor (2) or
the suction side three way switching valve (102) to thereby
regulate the refrigerant flow rate of each of the heat exchangers
(41, 45, 51) for regulation of the capability to provide air
conditioning and for regulation of the capability to provide
refrigeration. More specifically, the controller (80) controls the
inverter compressor (2) or the suction side three way switching
valve (102) based on the pressure difference between the
refrigerant low pressure (evaporating pressure) and its target
pressure (hereinafter referred to just as the "refrigerant pressure
difference"). The refrigerant pressure difference on the air
conditioning side is the difference between the pressure detected
by the low pressure sensor (65) and its target pressure, while the
refrigerant pressure difference on the refrigeration side is the
difference between the pressure detected by the low pressure sensor
(66) and its target pressure.
[0116] For example, when in the cooling/refrigeration operating
mode the load increases and, as a result, both the refrigerant
pressure difference on the air conditioning side and the
refrigerant pressure difference on the refrigeration side increase,
the controller (80) controls the operating volume of the inverter
compressor (2) to increase. In other words, the flow volume
distribution ratio of the second and third ports of the suction
side three way switching valve (102) remains unchanged, but the
flow rate of refrigerant flowing through each port increases. As a
result of this, the flow rate of refrigerant of each of the indoor
heat exchanger (41), the cold storage heat exchanger (45), and the
freeze storage heat exchanger (51) increases, and both the
capability to provide cooling and the capability to provide cold
storage/freeze storage are enhanced. As the load increases, the low
pressure of refrigerant becomes higher than the target pressure.
When either one of the load on the air conditioning side and the
load on the refrigeration side increases, the controller (80)
controls the operating volume of the inverter compressor (2) to
increase and changes the flow rate distribution ratio of the
suction side three way switching valve (102). In other words, the
total flow volume of refrigerant of the suction side three way
switching valve (102) is increased and, in addition, in order that
the amount thus increased may flow through ports on the side that
has undergone an increase in load, the flow volume distribution
ratio of the suction side three way switching valve (102) is
changed.
[0117] On the contrary, when the inverter compressor (2) is being
operated at its maximum volume, the controller (80) gives
preference to one side with a greater refrigerant pressure
difference than the other side and controls the suction side three
way switching valve (102) so that the refrigerant flow volume of
the one side is increased preferentially. For example, if the air
conditioning side has a greater refrigerant pressure difference
than the registration side, the flow volume distribution ratio
between each port is changed so that in the suction side three way
switching valve (102) the refrigerant flow rate of the second port
increases and the flow rate of refrigerant of the third port is
decreased by that much. To sum up, the total flow volume of
refrigerant flowing through the suction side three way switching
valve (102) remains unchanged. As a result of this, the refrigerant
flow rate of the indoor heat exchanger (41) increases and, as a
result, the capability to provide cooling is enhanced, while the
refrigerant flow rate of each of the cold storage heat exchanger
(45) and the freeze storage heat exchanger (51) decreases and, as a
result, the capability to provide cold storage/freeze storage
drops. Therefore, it becomes possible for these capabilities to
substantially balance with each other, thereby making it possible
to suppress considerable capability deficiency.
[0118] The controller (80) performs the same control operations in
the third heating/refrigeration operating mode as well. In
addition, when the load increases in the operating modes (i.e.
cooling, refrigeration, heating, first heating/refrigeration, and
second heating/refrigeration), the controller (80) controls the
operating volume of the inverter compressor (2) to increase.
EFFECTS OF THE EMBODIMENT
[0119] As described above, in accordance with the refrigerating
apparatus (1) of the embodiment, while the evaporating temperature
of the indoor heat exchanger (41) is kept higher than the
evaporating temperature of the cold storage and freeze storage heat
exchangers (45, 51), switching of the flow paths is accomplished by
the suction side three way switching valve (102). This allows the
refrigerating apparatus to efficiently switch from one operating
mode to another, without having to create an evaporating pressure
difference by a plurality of compressors and without the need for
separate provision of a pressure regulating valve.
VARIATIONS OF THE EMBODIMENT
[0120] In each variation of the embodiment, the controller (80)
controls, based on parameters other than the low pressure of
refrigerant, the inverter compressor (2) and the suction side three
way switching valve (102).
[0121] In a first variation of the embodiment, the controller (80)
controls the inverter compressor (2) et cetera based on the
temperature difference between the temperature of suction air in
each heat exchanger (41, 45, 51) and its target temperature
(hereinafter referred to just as the "air temperature difference").
In other words, the air temperature difference on the air
conditioning side is the difference between the temperature of air
drawn in by the indoor fan (43) and its target temperature. On the
other hand, the air temperature difference on the refrigeration
side is either the difference between the temperature of air drawn
in by the cold storage fan (47) and its target temperature or the
difference between the temperature of air drawn in by the freeze
storage fan (58) and its target temperature, whichever is
greater.
[0122] In this case, for example, when in the cooling/refrigeration
operating mode the load increases and, as a result, the air
temperature difference increases both on the air conditioning side
and on the refrigeration side, i.e., when the air temperature
exceeds the target temperature, the operating volume of the
inverter compressor (2) is increased. Here, when the inverter
compressor (2) is being operated at its maximum volume, one side
with a higher air temperature difference than the other side is
given preference and the suction side three way switching valve
(102) is controlled so that the refrigerant flow volume of the one
side is increased preferentially.
[0123] In a second variation of the embodiment, the controller (80)
controls the inverter compressor (2) et cetera based on the
temperature difference between the evaporating temperature of
refrigerant and its target temperature (hereinafter referred to
just as the "refrigerant temperature difference"). In other words,
the refrigerant temperature difference on the air conditioning side
in the cooling operating mode means the difference between the
temperature of refrigerant in the indoor heat exchanger (41) and
its target temperature, while on the other hand the refrigerant
temperature difference on the air conditioning side in the heating
operating mode means the difference between the temperature of
refrigerant in the outdoor heat exchanger (4) and its target
temperature. On the other hand, the refrigerant temperature
difference on the refrigeration side is either the difference
between the temperature of refrigerant in the cold storage heat
exchanger (45) and its target temperature or the difference between
the temperature of refrigerant in the freeze storage heat exchanger
(51) and its target temperature, whichever is greater.
[0124] In this case, for example, when in the cooling/refrigeration
operating mode the load increases and, as a result, the refrigerant
temperature difference increases both on the air conditioning side
and on the refrigeration side, i.e., when the refrigerant
evaporating temperature exceeds the target temperature, the
operating volume of the inverter compressor (2) is increased. Here,
when the inverter compressor (2) is being operated at its maximum
volume, one side with a higher refrigerant temperature difference
than the other side is given preference and the suction side three
way switching valve (102) is controlled so that the refrigerant
flow volume of the one side is increased preferentially.
[0125] In a third variation of the embodiment, the indoor heat
exchanger (41), the cold storage heat exchanger (45), and the
freeze storage heat exchanger (51) are each provided in a
respective plural number. The indoor heat exchangers (41), the cold
storage heat exchangers (45), and the freeze storage heat
exchangers (51) are arranged in parallel respectively. And, the
controller (80) controls the inverter compressor (2) et cetera
based on the number of heat exchangers (41, 45, 51) in operation or
based on the ratio of the number of heat exchangers (41, 45, 51) in
operation. Basically, the controller (80) controls the inverter
compressor (2) et cetera based on the number of heat exchangers in
operation if the heat exchangers (41, 45, 51) are provided equally
in number to each other, while if the heat exchangers (41, 45, 51)
are provided differently in number from each other, the controller
(80) controls the inverter compressor (2) et cetera based on the
ratio of the number of heat exchangers in operation.
[0126] In this case, for example, when in the cooling/refrigeration
operating mode the load increases and, as a result, the number of
heat exchangers (41, 45, 51) in operation or the ratio of the
number of heat exchangers (41, 45, 51) in operation increases, the
operating volume of the inverter compressor (2) is increased. Here,
when the inverter compressor (2) is being operated at its maximum
volume, one side with a larger number of heat exchangers in
operation or with a higher ratio of the number of heat exchangers
in operation is given preference and the suction side three way
switching valve (102) is controlled so that the refrigerant flow
volume of the one side is increased preferentially.
[0127] In a fourth variation of the embodiment, the controller (80)
controls the suction side three way switching valve (102) based on
the above-mentioned refrigerant low pressure, when there is an
increase in refrigerant high pressure, refrigerant condensing
temperature or outside air temperature. Here, the refrigerant high
pressure is a pressure detected by the high pressure sensor (61).
The refrigerant condensing temperature in the cooling operating
mode means the temperature of refrigerant in the outdoor heat
exchanger (4), while on the other hand it means the temperature of
refrigerant in the indoor heat exchanger (41) in the heating
operating mode. The outside air temperature is a temperature
detected by the outside air temperature sensor (70).
[0128] More specifically, when it is decided that the load has
increased due to an increase in refrigerant high pressure,
refrigerant condensing temperature, or outside air temperature, the
controller (80) controls the operating volume of the inverter
compressor (2) to increase. At this time, if the inverter
compressor (2) is being operated at its maximum volume, the air
conditioning side or the refrigeration side, whichever is lower in
refrigerant low pressure, is given preference and the suction side
three way switching valve (102) is controlled so that the
refrigerant flow volume of the preferential side is increased.
Alternatively, the controller (80) may control the suction side
three way switching valve (102) so that the refrigerant flow volume
of the air conditioning side or the refrigeration side, whichever
is lower in (a) refrigerant low pressure's target pressure (instead
of the refrigerant low pressure), (b) refrigerant evaporating
temperature, or target temperature of the temperature of incoming
air, is increased.
OTHER EMBODIMENTS
[0129] In the above-described embodiment, the discharge side three
way switching valve (101) is provided as a flow rate regulating
means. However, the discharge side three way switching valve (101)
may be a four way switching valve capable of flow rate regulation.
Also in each case, the same operation/working effect as the
above-described embodiment is obtained.
INDUSTRIAL APPLICABILITY
[0130] As has been described above, the present invention is useful
for refrigerating apparatuses installed in convenience stores,
supermarkets et cetera and provided with air conditioning heat
exchangers and refrigeration heat exchangers.
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