U.S. patent application number 11/989308 was filed with the patent office on 2010-06-10 for refrigeration apparatus.
Invention is credited to Azuma Kondo, Kazuyoshi Nomura, Yoshinari Oda, Masaaki Takegami, Kenji Tanimoto.
Application Number | 20100139312 11/989308 |
Document ID | / |
Family ID | 37683246 |
Filed Date | 2010-06-10 |
United States Patent
Application |
20100139312 |
Kind Code |
A1 |
Takegami; Masaaki ; et
al. |
June 10, 2010 |
Refrigeration apparatus
Abstract
A refrigeration apparatus (1) is disclosed which is provided
with multiple systems of utilization-side heat exchangers (20, 30,
40) and in which liquid-side interunit piping lines (53, 54, 55)
are combined into a single liquid-side interunit piping line in
multiple systems of liquid lines. When the refrigeration apparatus
(1) provides space heating of 100% heat recovery without the use of
an outdoor heat exchanger (15), the flow of refrigerant in a
refrigerant circuit (50) is stabilized even when the temperature of
outside air is low, thereby preventing the capacity to provide
refrigeration from decreasing. In addition, in order to prevent
shutdown of the refrigeration apparatus (1) due to malfunction, a
liquid refrigerant inflow passageway (66) is connected to a heat
source-side liquid pipe (62) of an outdoor unit (10), the heat
source-side liquid pipe (62) being connected to an integrated
liquid pipe (53) of the liquid-side interunit piping lines (53, 54,
55), and to an inlet port of the a receiver (17), and a switch
valve (SV1) capable of being on-off controlled is disposed in the
liquid refrigerant inflow passageway (66).
Inventors: |
Takegami; Masaaki; (Osaka,
JP) ; Tanimoto; Kenji; (Osaka, JP) ; Oda;
Yoshinari; (Osaka, JP) ; Nomura; Kazuyoshi;
(Osaka, JP) ; Kondo; Azuma; (Osaka, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
37683246 |
Appl. No.: |
11/989308 |
Filed: |
July 20, 2006 |
PCT Filed: |
July 20, 2006 |
PCT NO: |
PCT/JP2006/314381 |
371 Date: |
January 24, 2008 |
Current U.S.
Class: |
62/498 ;
62/513 |
Current CPC
Class: |
Y02B 30/741 20130101;
F25B 2400/075 20130101; F25B 2700/1931 20130101; F25B 2400/16
20130101; F25B 13/00 20130101; F25B 2500/31 20130101; F25B
2313/0231 20130101; F25B 2313/02743 20130101; F25B 2600/021
20130101; F25B 2400/22 20130101; Y02B 30/70 20130101; F25B
2600/2519 20130101 |
Class at
Publication: |
62/498 ;
62/513 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F25B 41/00 20060101 F25B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2005 |
JP |
2005-215543 |
Jan 20, 2006 |
JP |
2006-012115 |
Claims
1. A refrigeration apparatus comprising: a heat source-side unit
(10) including a compression mechanism (11D, 11E), a heat
source-side heat exchanger (15), and a receiver (17); a first
utilization-side unit (30, 40) including a first utilization-side
heat exchanger (31, 41); a second utilization-side unit (20)
including a second utilization-side heat exchanger (21); and a
gas-side interunit piping line (51, 52) and a liquid-side interunit
piping line (53, 54, 55) which establish connections between each
unit (10, 20, 30, 40) to thereby constitute a refrigerant circuit
(50); the gas-side interunit piping line (51, 52) including: a
first gas-side interunit piping line (51) which is connected to the
heat source-side unit (10) and to the first utilization-side unit
(30, 40); and a second gas-side interunit piping line (52) which is
connected to the heat source-side unit (10) and to the second
utilization-side unit (20); the liquid-side interunit piping line
(53, 54, 55) including: an integrated liquid pipe (53) which is
connected to the heat source-side unit (10); a first branch liquid
pipe (54) which diverges from the integrated liquid pipe (53) to
connect to the first utilization-side unit (30, 40); and a second
branch liquid pipe (55) which diverges from the integrated liquid
pipe (53) to connect to the second utilization-side unit (20);
wherein the refrigeration apparatus further comprises: a liquid
refrigerant inflow passageway (66) which is connected to a heat
source-side liquid pipe (62) of the heat source-side unit (10), the
heat source-side liquid pipe (62) being connected to the integrated
liquid pipe (53) of the liquid-side interunit piping line (53, 54,
55), and to an inlet port of the receiver (17); and a switch valve
(SV1) which is disposed in the liquid refrigerant inflow passageway
(66) and which is capable of being on-off controlled.
2. The refrigeration apparatus of claim 1, wherein a plurality of
the second utilization-side units (20) are connected in parallel to
the heat source-side unit (10).
3. The refrigeration apparatus of claim 1, wherein the first
utilization-side unit (30, 40) is a cooling machine for providing
compartment cooling and the heat source-side unit (10) and the
first utilization-side unit (30, 40) together constitute a first
system-side circuit (50A) in which refrigerant is circulated in one
direction; and wherein the second utilization-side unit (20) is an
air conditioning machine for providing indoor air conditioning and
the heat source-side unit (10) and the second utilization-side unit
(20) together constitute a second system-side circuit (50B) in
which refrigerant is reversibly circulated.
4. The refrigeration apparatus of claim 1, wherein the
refrigeration apparatus further comprises control means (95) for
performing on-off control of the switch valve (SV1) in response to
the operation state.
5. The refrigeration apparatus of claim 4, wherein the control
means (95) is configured such that in an operation state in which
the second utilization-side heat exchanger (21) functions as a
condenser while the first utilization-side heat exchanger (31, 41)
functions as an evaporator, the switch valve (SV1) is placed either
in the closed state if the discharge pressure of the compression
mechanism (11D, 11E) is below a predetermined value or in the
opened state if the discharge pressure of the compression mechanism
(11D, 11E) increases to equal or exceed the predetermined
value.
6. The refrigeration apparatus of claim 4, wherein the control
means (95) is configured such that in an operation state in which
the second utilization-side heat exchanger (21) functions as a
condenser while the first utilization-side heat exchanger (31, 41)
functions as an evaporator, the switch valve (SV1) is placed either
in the closed state if the amount of liquid refrigerant accumulated
in the second utilization-side heat exchanger (21) and the
liquid-side interunit piping line (53, 54, 55) is below a
predetermined value or in the opened state if it is estimated that
the liquid refrigerant amount accumulated reaches the predetermined
value or above.
7. The refrigeration apparatus of claim 4, wherein the control
means (95) is configured such that in an operation state in which
the second utilization-side heat exchanger (21) functions as a
condenser while the first utilization-side heat exchanger (31, 41)
functions as an evaporator, the switch valve (SV1) is placed either
in the closed state if the temperature of liquid refrigerant in the
second utilization-side heat exchanger (21) is below a
predetermined value or in the opened state if the liquid
refrigerant temperature increases to equal or exceed the
predetermined value.
8. The refrigeration apparatus of claim 4, wherein the control
means (95) is configured such that in an operation state in which
the second utilization-side heat exchanger (21) functions as a
condenser while the first utilization-side heat exchanger (31, 41)
functions as an evaporator, the switch valve (SV1) is placed either
in the closed state if the pressure of liquid refrigerant in the
liquid-side interunit piping line (53, 54, 55) is below a
predetermined value or in the opened state if the liquid
refrigerant pressure increases to equal or exceed the predetermined
value.
Description
TECHNICAL FIELD
[0001] The present invention relates in general to refrigeration
apparatuses, and more particularly to refrigeration apparatuses
which have a plurality of utilization-side heat exchangers for cold
storage/freeze storage and air conditioning and which are operable
in an operation mode of 100% heat recovery between/among each
utilization-side heat exchanger.
BACKGROUND ART
[0002] In the past, a refrigeration apparatus of the type which
performs a refrigeration cycle has been known in the art. Such a
refrigeration apparatus has been used widely as an air conditioner
for providing cooling/heating of an indoor space and as a cooler
for providing cooling of a showcase compartment for food cold
storage/freeze storage. This type of refrigeration apparatus
includes a refrigeration apparatus which provides both air
conditioning and cold storage/freeze storage (for example, see
Patent Document 1). This refrigeration apparatus is installed, for
example, in a convenience store, and both store space air
conditioning and showcase cooling are accomplished by installation
of the single refrigeration apparatus.
[0003] The aforesaid refrigeration apparatus is configured as
follows. A plurality of utilization-side heat exchangers (heat
exchangers for cold storage, freeze storage, and air conditioning
which are disposed respectively in utilization-side units (cold
storage showcases, freeze storage showcases, and air conditioning
indoor units)) are connected, by liquid- and gas-side interunit
piping lines, in parallel to a heat source-side (outdoor) heat
exchanger of a heat source-side (outdoor) unit which is installed
outdoors.
[0004] Here, in the case where the refrigerant circuit has two
systems, namely a first system-side circuit for cold storage/freeze
storage and a second system-side circuit for air conditioning, two
interunit piping lines are generally arranged for each of a liquid
and gas lines. On the other hand, in order to reduce the number of
interunit piping lines, it is proposed that liquid lines of two
systems share a single liquid-side interunit piping line (see
Patent Document 2).
[0005] More specifically, the refrigerant circuit of this apparatus
is configured as shown in FIG. 10. Referring to FIG. 10, an outdoor
unit (101), an indoor unit (102), a cold storage showcase (cold
storage unit) (103), and a freeze storage showcase (freeze storage
unit) (104) are shown. The outdoor unit (101) is provided with
compression mechanisms (105, 106), an outdoor heat exchanger (107),
an outdoor expansion valve (108), and a receiver (109). The indoor
unit (102) is provided with an indoor heat exchanger (air
conditioning heat exchanger) (110) and an indoor expansion valve
(111). In addition, the cold storage showcase (103) is provided
with a cold storage heat exchanger (112) and a cold storage
expansion valve (113). The freeze storage showcase (104) is
provided with a freeze storage heat exchanger (114), a freeze
storage expansion valve (115), and a booster compressor (116).
[0006] A refrigerant circuit (120) of the refrigeration apparatus
includes a first system-side circuit for cold storage/freeze
storage and a second system-side circuit for air conditioning. The
first system-side circuit is configured such that refrigerant is
circulated in one direction between the outdoor heat exchanger
(107) and the cold and freeze storage heat exchangers (112, 114).
The second system-side circuit is configured such that refrigerant
is circulated reversibly between the outdoor heat exchanger (107)
and the indoor heat exchanger (110). And, a single liquid-side
interunit piping line (121) is shared between the liquid line of
the first system-side circuit and the liquid line of the second
system-side circuit.
[0007] In the aforesaid refrigeration apparatus, it is possible to
provide indoor space air conditioning and cooling of each showcase
while the outdoor heat exchanger (107) (installed outdoors) is used
as a heat source and, in addition, it is also possible to provide,
without the use of the outdoor heat exchanger (107), heating and
cold storage/freeze storage with 100% heat recovery in which the
indoor heat exchanger (110) functions as a condenser and the cold
and freeze storage heat exchangers (112, 114) function as
evaporators.
[0008] Now, when performing a 100% heat recovery operation mode in
the refrigerant circuit (120) provided with the single liquid-side
interunit piping line (121), discharged refrigerant from the
compression mechanisms (105, 106) is circulated in the refrigerant
circuit (120) such that it is condensed in the indoor heat
exchanger (110), evaporated in the cold and freeze storage heat
exchangers (112, 114), and drawn again into the compression
mechanisms (105, 106). Stated another way, at this time, it is
required that liquid refrigerant condensed in the indoor heat
exchanger (110) is not allowed to flow in the direction of the heat
source-side heat exchanger (107) from the receiver (109) but is to
be introduced into the cold and freeze storage heat exchangers
(112, 114).
[0009] However, since the pressure in the receiver (109) drops, for
example, when the temperature of outside air is low, the internal
pressure of the liquid-side interunit piping line (121) likewise
drops, and liquid refrigerant exiting the indoor heat exchanger
(110) is liable to flow into the receiver (109) from the
liquid-side interunit piping line (121), so that the volume of flow
of refrigerant flowing to the cold and freeze storage heat
exchangers (112, 114) may run short. And, if the volume of flow of
refrigerant in the cold and freeze storage heat exchangers (112,
114) is insufficient, this reduces the capacity to provide cooling
of the compartment of each of the showcases (103, 104).
[0010] To cope with the above, in the refrigeration apparatus, a
relief valve (117) is disposed in a refrigerant passageway
extending from the liquid-side interunit piping line (121) to the
receiver (109). The relief valve (117) is a valve which is
configured such that although it is placed in the opened state if
the pressure of refrigerant in the liquid-side interunit piping
line (121) increases to equal or exceed a predetermined value, it
remains in the closed state until reaching the predetermined value.
And, by setting the working pressure of the relief valve (117) to a
higher level than the pressure of the liquid-side interunit piping
line (121) during the 100% heat recovery operation mode, the inflow
of liquid refrigerant into the receiver (109) during the 100% heat
recovery operation mode is prevented so that the flow of
refrigerant in the refrigerant circuit (120) is stabilized even
when the temperature of outside air is low, thereby to prevent the
capacity to provide refrigeration from falling.
[0011] In addition, it is also possible for the refrigeration
apparatus to perform a refrigerant cycle for space heating in which
the outdoor heat exchanger (107) functions as an evaporator.
However, at that time, the relief valve (117) is placed in the
opened state because the suction pressure of the compressor (106)
is applied to the relief valve (117). Also note that during the
cooling operation mode no refrigerant flows through the passageway
in which the relief valve (117) is disposed.
Patent Document 1: JP-A-2001-280749
Patent Document 2: JP-A-2005-134103
DISCLOSURE OF THE INVENTION
Problems that the Invention Seeks to Overcome
[0012] For example, in the case where a high heating capacity is
required during the 100% heat recovery operation mode in the
aforesaid apparatus, it is conceivable that the amount of liquid
refrigerant condensed in the indoor heat exchanger (100) exceeds
the amount of refrigerant required in the cold and freeze storage
heat exchangers (112, 114), leading to the result that liquid
refrigerant becomes excessive between the indoor heat exchanger
(110) and the liquid-side interunit piping line (121). On the other
hand, if at this time there is a request for increasing the
capacity to provide cooling storage/freezing storage, the operation
capacity of the compression mechanisms (105, 106) increases, and
the amount of discharge gas refrigerant supplied to the indoor heat
exchanger (110) will increase.
[0013] Even if the amount of discharge gas refrigerant is increased
in the way as described above when there is excess liquid
refrigerant in the indoor heat exchanger (110) and the liquid-side
interunit piping line (121), gas refrigerant will not readily flow
through the indoor heat exchanger (110) because the liquid-side
interunit piping line (121) is filled up with liquid refrigerant,
and the discharge pressure of the compression mechanisms (105, 106)
gradually increases. In this case, with the increase in the
discharge pressure, the liquid pressure of the liquid-side
interunit piping line (121) also increases. If this liquid pressure
exceeds the working pressure of the relief valve (117), the relief
valve (117) is placed in the opened state, thereby making it
possible to permit escape of the liquid refrigerant to the receiver
(109), and no operation problems will take place.
[0014] However, the discharge pressure of the compressors (105,
106) increases too much in some cases before the relief valve (117)
is placed in the opened state, thereby causing a pressure switch
(HPS) for high pressure protection to activate. As a result, the
compressors (105, 106) stop operating and the apparatus may stop
operating due to malfunction.
[0015] With the above problems in mind, the present invention was
made. Accordingly, an object of the present invention is to prevent
the capability to provide refrigeration from falling by stabilizing
the flow of refrigerant in a refrigerant circuit even when the
temperature of outside air is low, and to avoid shutdown due to
malfunction, at the time when providing heating of 100% heat
recovery without the use of an outdoor heat exchanger in a
refrigeration apparatus which is provided with plural systems of
utilization-side heat exchangers and in which a single liquid-side
interunit piping line is shared among a plurality of liquid
lines.
Means for Overcoming the Problems
[0016] The present invention provides, as a first aspect, a
refrigeration apparatus comprising: a heat source-side unit (10)
including a compression mechanism (11D, 11E), a heat source-side
heat exchanger (15), and a receiver (17); a first utilization-side
unit (30, 40) including a first utilization-side heat exchanger
(31, 41); a second utilization-side unit (20) including a second
utilization-side heat exchanger (21); and a gas-side interunit
piping line (51, 52) and a liquid-side interunit piping line (53,
54, 55) which establish connections between each unit (10, 20, 30,
40) to thereby constitute a refrigerant circuit (50), wherein the
gas-side interunit piping line (51, 52) includes: a first gas-side
interunit piping line (51) which is connected to the heat
source-side unit (10) and to the first utilization-side unit (30,
40); and a second gas-side interunit piping line (52) which is
connected to the heat source-side unit (10) and to the second
utilization-side unit (20), and wherein the liquid-side interunit
piping line (53, 54, 55) includes: an integrated liquid pipe (53)
which is connected to the heat source-side unit (10); a first
branch liquid pipe (54) which diverges from the integrated liquid
pipe (53) to connect to the first utilization-side unit (30, 40);
and a second branch liquid pipe (55) which diverges from the
integrated liquid pipe (53) to connect to the second
utilization-side unit (20).
[0017] And the refrigeration apparatus of the first aspect is
characterized in that the refrigeration apparatus further
comprises: a liquid refrigerant inflow passageway (66) which is
connected to a heat source-side liquid pipe (62) of the heat
source-side unit (10), the heat source-side liquid pipe (62) being
connected to the integrated liquid pipe (53) of the liquid-side
interunit piping line (53, 54, 55), and to an inlet port of the
receiver (17); and a switch valve (SV1) which is disposed in the
liquid refrigerant inflow passageway (66) and which is capable of
being on-off controlled.
[0018] In the first aspect of the present invention, during the
100% heat recovery operation mode in which the second
utilization-side heat exchanger (21) functions as a condenser while
the first utilization-side heat exchanger (31, 41) functions as an
evaporator, refrigerant flows sequentially through the compression
mechanism (11D, 11E), through the second gas-side interunit piping
line (52), through the second utilization-side heat exchanger (21),
through the second branch liquid pipe (55), through the first
branch liquid pipe (54), through the first utilization-side heat
exchanger (31, 41), and through the first gas-side interunit piping
line (51). At this time, if the switch valve (SV1) is placed in the
closed state, no refrigerant flows towards any of the first branch
liquid pipe (54), the integrated liquid pipe (53), the heat
source-side liquid pipe (62), the liquid refrigerant inflow
passageway (66), and the receiver (17). Accordingly, the
refrigeration apparatus operates wherein the quantity of heat of
condensation of the second utilization-side heat exchanger (21) and
the quantity of heat of evaporation of the first utilization-side
heat exchanger (31, 41) are in balance with each other.
[0019] On the other hand, if the operation capacity of the
compression mechanism (11D, 11E) is increased when there is excess
refrigerant in the second utilization-side heat exchanger (21) and
the liquid-side interunit piping line (53, 54, 55), it is best to
perform an operation that places the switch valve (SV1) in the
opened state. When this is done, it becomes possible to permit
escape of the liquid refrigerant congested in the second
utilization-side heat exchanger (21) and the liquid-side interunit
piping line (53, 54, 55) to the receiver (17) from the first branch
liquid pipe (54) by way of the integrated liquid pipe (53), the
heat source-side liquid pipe (62), and the liquid refrigerant
inflow passageway (66), whereby the discharge pressure of the
compression mechanism (11D, 11E) is prevented from increasing too
much.
[0020] The present invention provides, as a second aspect according
to the first aspect, a refrigeration apparatus which is
characterized in that a plurality of the second utilization-side
units (20) are connected in parallel to the heat source-side unit
(10).
[0021] In the second aspect of the present invention, when, during
the 100% heat recovery operation mode, a selected one of the second
utilization-side units (20) is placed in the thermo-off state
(which is a state that performs an air supply operation in which
refrigerant either stops circulating through the second
utilization-side heat exchanger (21) or is allowed to flow
therethrough, but in very small amount), the expansion mechanism
which is connected to the second utilization-side unit (20) is
either placed in the fully closed state or is set such that
although it is opened the degree of opening thereof is very small.
At this time, since the rest of the second utilization-side units
(20) continue to provide heating (space heating), discharged
refrigerant from the compression mechanism (11D, 11E) is supplied
also to the second utilization-side heat exchanger (21) placed in
the thermo-off state. However, little refrigerant flows in the
thermo-offed, second utilization-side heat exchanger (21) and, as a
result, refrigerant is rapidly accumulated therein.
[0022] At this time, if there is a request to increase the
refrigeration capacity of the first utilization-side heat exchanger
(31, 41), an operation to increase the capacity of the compression
mechanism (11D, 11E) is performed. As a result, the discharge
pressure of the compression mechanism (11D, 11E) increases, so that
if the switch valve (SV1) of the liquid refrigerant inflow
passageway (66) continues to remain in the closed state, this may
lead to the possibility that the discharge pressure of the
compression mechanism (11D, 11E) increases too much, but
nonetheless an operation to place the switch valve (SV1) in the
opened state is performed in the second aspect of the present
invention, thereby permitting escape of the liquid refrigerant to
the receiver (17), and the discharge pressure of the compression
mechanism (11D, 11E) is prevented from increasing too much.
[0023] The present invention provides, as a third aspect according
to either the first or the second aspect, a refrigeration apparatus
which is characterized in that the first utilization-side unit (30,
40) is a cooling machine for providing compartment cooling and the
heat source-side unit (10) and the first utilization-side unit (30,
40) together constitute a first system-side circuit (50A) in which
refrigerant is circulated in one direction; and that the second
utilization-side unit (20) is an air conditioning machine for
providing indoor air conditioning and the heat source-side unit
(10) and the second utilization-side unit (20) together constitute
a second system-side circuit (50B) in which refrigerant is
reversibly circulated.
[0024] In the third aspect of the present invention, the first
utilization-side heat exchanger (31, 41) in the first system-side
circuit (50A) provides compartment cooling while the second
utilization-side heat exchanger (21) in the second system-side
circuit (50B) provides indoor air conditioning (space
cooling/heating). In this case, it is possible to prevent the
discharge pressure of the compression mechanism (11D, 11E) from
increasing too much by placing the switch valve (SV1) in the opened
state, even if during the 100% heat recovery operation mode in
which the second utilization-side heat exchanger (21) functions as
a condenser while the first utilization-side heat exchanger (31,
41) functions as an evaporator, the operation capacity of the
compression mechanism (11D, 11E) is increased when there is excess
refrigerant in the second utilization-side heat exchanger (21) and
the liquid-side interunit piping line (53, 54, 55).
[0025] The present invention provides, as a fourth aspect according
to any one of the first to third aspects, a refrigeration apparatus
which is characterized in that the refrigeration apparatus further
comprises a control means (95) for performing on-off control of the
switch valve (SV1) in response to the operation state.
[0026] In the fourth aspect of the present invention, the switch
valve (SV1) is placed in the opened state, for example, when the
discharge pressure of the compression mechanism (11D, 11E)
increases or when although there is no increase in the discharge
pressure, there is an accumulation of liquid refrigerant between
the second utilization-side heat exchanger (21) and the liquid-side
interunit piping line (53, 54, 55) during the 100% heat recovery
operation mode. On the other hand, the switch valve (SV1) is placed
in the closed state when the second system-side circuit (50B)
provides cooling of the utilization side (for example, when the
second system-side circuit (50B) is a circuit for air conditioning
and is in operation to provide space cooling) or when the
compression mechanism (11D, 11E) is placed at rest. In addition,
even in the case where the second utilization-side heat exchanger
(21) functions as a condenser, an operation to place the switch
valve (SV1) in the opened state is performed in such an operation
state that the heat source-side heat exchanger (15) is employed as
an evaporator.
[0027] The present invention provides, as a fifth aspect according
to the fourth aspect, a refrigeration apparatus which is
characterized in that the control means (95) is configured such
that in an operation state in which the second utilization-side
heat exchanger (21) functions as a condenser while the first
utilization-side heat exchanger (31, 41) functions as an
evaporator, the switch valve (SV1) is placed either in the closed
state if the discharge pressure of the compression mechanism (11D,
11E) is below a predetermined value or in the opened state if the
discharge pressure of the compression mechanism (11D, 11E)
increases to equal or exceed the predetermined value.
[0028] In the fifth aspect of the present invention, during the
100% heat recovery operation mode in which the second
utilization-side heat exchanger (21) functions as a condenser while
the first utilization-side heat exchanger (31, 41) functions as an
evaporator, the switch valve (SV1) is placed in the closed state if
the discharge pressure of the compression mechanism (11D, 11E) is
below the predetermined value. Accordingly, the refrigeration
apparatus operates wherein the quantity of heat of condensation of
the second utilization-side heat exchanger (21) and the quantity of
heat of evaporation of the first utilization-side heat exchanger
(31, 41) are in balance with each other. On the other hand, the
switch valve (SV1) is placed in the opened state if the discharge
pressure of the compression mechanism (11D, 11E) reaches the
predetermined value or above, thereby permitting escape of the high
pressure refrigerant between the second utilization-side heat
exchanger (21) and the liquid-side interunit piping line (53, 54,
55) into the receiver (17). By setting the set pressure of the
switch valve (SV1) at which it is placed in the opened state to
fall below the working pressure of a pressure switch for high
pressure protection, it becomes possible to prevent the discharge
pressure of the compression mechanism (11D, 11E) from increasing
too much.
[0029] The present invention provides, as a sixth aspect according
to the fourth aspect, a refrigeration apparatus which is
characterized in that the control means (95) is configured such
that in an operation state in which the second utilization-side
heat exchanger (21) functions as a condenser while the first
utilization-side heat exchanger (31, 41) functions as an
evaporator, the switch valve (SV1) is placed either in the closed
state if the amount of liquid refrigerant accumulated in the second
utilization-side heat exchanger (21) and the liquid-side interunit
piping line (53, 54, 55) is below a predetermined value or in the
opened state if it is estimated that the liquid refrigerant amount
accumulated reaches the predetermined value or above. In this case,
it is possible to estimate that liquid refrigerant is accumulated
in the second utilization-side heat exchanger (21) and the
liquid-side interunit piping line (53, 54, 55) from the fact that
the value, detected by a sensor for detection of the temperature of
gas refrigerant in the second utilization-side heat exchanger (21)
during the 100% heat recovery operation mode, approaches the
saturated temperature corresponding to the pressure.
[0030] In the sixth aspect of the present invention, during the
100% heat recovery operation mode in which the second
utilization-side heat exchanger (21) functions as a condenser while
the first utilization-side heat exchanger (31, 41) functions as an
evaporator, the switch valve (SV1) is placed in the closed state if
the amount of liquid refrigerant accumulated in the second
utilization-side heat exchanger (21) and the liquid-side interunit
piping line (53, 54, 55) is below the predetermined value.
Accordingly, the refrigeration apparatus operates wherein the
quantity of heat of condensation of the second utilization-side
heat exchanger (21) and the quantity of heat of evaporation of the
first utilization-side heat exchanger (31, 41) are in balance with
each other. On the other hand, the switch valve (SV1) is placed in
the opened state if it is estimated that the liquid refrigerant
amount accumulated reaches the predetermined value or above,
thereby permitting escape of the high pressure refrigerant between
the second utilization-side heat exchanger (21) and the liquid-side
interunit piping line (53, 54, 55) into the receiver (17). This
therefore makes it possible to prevent excess accumulation of
liquid refrigerant in the second utilization-side heat exchanger
(21) and the liquid-side interunit piping line (53, 54, 55).
[0031] The present invention provides, as a seventh aspect
according to the fourth aspect, a refrigeration apparatus which is
characterized in that the control means (95) is configured such
that in an operation state in which the second utilization-side
heat exchanger (21) functions as a condenser while the first
utilization-side heat exchanger (31, 41) functions as an
evaporator, the switch valve (SV1) is placed either in the closed
state if the temperature of liquid refrigerant in the second
utilization-side heat exchanger (21) is below the predetermined
value or in the opened state if the liquid refrigerant temperature
increases to equal or exceed the predetermined value.
[0032] In the seventh aspect of the present invention, during the
100% heat recovery operation mode in which the second
utilization-side heat exchanger (21) functions as a condenser while
the first utilization-side heat exchanger (31, 41) functions as an
evaporator, the switch valve (SV1) is placed in the closed state if
the temperature of liquid refrigerant in the second
utilization-side heat exchanger (21) is below a predetermined
value. Accordingly, the refrigeration apparatus operates wherein
the quantity of heat of condensation of the second utilization-side
heat exchanger (21) and the quantity of heat of evaporation of the
first utilization-side heat exchanger (31, 41) are in balance with
each other. On the other hand, the switch valve (SV1) is placed in
the opened state if the liquid refrigerant temperature increases to
equal or exceed the predetermined value, thereby permitting escape
of the high pressure refrigerant between the second
utilization-side heat exchanger (21) and the liquid-side interunit
piping line (53, 54, 55) into the receiver (17). By setting the set
pressure of the switch valve (SV1) at which it is placed in the
opened state to fall below the working pressure of a pressure
switch for high pressure protection, it becomes possible to prevent
the discharge pressure of the compression mechanism (11D, 11E) from
increasing too much.
[0033] The present invention provides, as an eighth aspect
according to the fourth aspect, a refrigeration apparatus which is
characterized in that the control means (95) is configured such
that in an operation state in which the second utilization-side
heat exchanger (21) functions as a condenser while the first
utilization-side heat exchanger (31, 41) functions as an
evaporator, the switch valve (SV1) is placed either in the closed
state if the pressure of liquid refrigerant in the liquid-side
interunit piping line (53, 54, 55) is below a predetermined value
or in the opened state if the liquid refrigerant pressure increases
to equal or exceed the predetermined value.
[0034] In the eighth aspect of the present invention, during the
100% heat recovery operation mode in which the second
utilization-side heat exchanger (21) functions as a condenser while
the first utilization-side heat exchanger (31, 41) functions as an
evaporator, the switch valve (SV1) is placed in the closed state if
the pressure of liquid refrigerant in the liquid-side interunit
piping line (53, 54, 55) is below the predetermined value.
Accordingly, the refrigeration apparatus operates wherein the
quantity of heat of condensation of the second utilization-side
heat exchanger (21) and the quantity of heat of evaporation of the
first utilization-side heat exchanger (31, 41) are in balance with
each other. On the other hand, the switch valve (SV1) is placed in
the opened state if the liquid refrigerant pressure increases to
equal or exceed the predetermined value, thereby permitting escape
of the high pressure refrigerant in the liquid-side interunit
piping line (53, 54, 55) into the receiver (17). By setting the set
pressure of the switch valve (SV1) at which it is placed in the
opened state to fall below the working pressure of a pressure
switch for high pressure protection, it becomes possible to prevent
the discharge pressure of the compression mechanism (11D, 11E) from
increasing too much.
ADVANTAGEOUS EFFECTS OF THE INVENTION
[0035] In the refrigeration apparatus of the present invention
capable of operating, without the use of the heat source-side heat
exchanger (15), in a 100% heat recovery operation mode in which the
second utilization-side heat exchanger (21) and the first
utilization-side heat exchanger (31, 41) function respectively as a
condenser and as an evaporator, the liquid refrigerant inflow
passageway (66) is connected to the heat source-side liquid pipe
(62) of the heat source-side unit (10), the heat source-side liquid
pipe (62) being connected to the integrated liquid pipe (53) of the
liquid-side interunit piping line (53, 54, 55), and to the inlet
port of the receiver (17) and the switch valve (SV1) capable of
being on-off controlled is disposed in the liquid refrigerant
inflow passageway (66). Therefore, by performing such a 100% heat
recovery operation mode with the switch valve (SV1) placed in the
closed state, the refrigeration apparatus operates wherein the
quantity of heat of condensation of the second utilization-side
heat exchanger (21) and the quantity of heat of evaporation of the
first utilization-side heat exchanger (31, 41) are in balance with
each other.
[0036] On the other hand, if the operation capacity of the
compression mechanism (11D, 11E) is increased when there is excess
refrigerant in the second utilization-side heat exchanger (21) and
the liquid-side interunit piping line (53, 54, 55), an operation to
place the switch valve (SV1) in the opened state is performed,
thereby permitting escape of the liquid refrigerant accumulated in
the second utilization-side heat exchanger (21) and the liquid-side
interunit piping line (53, 54, 55) to the receiver (17) from the
first branch liquid pipe (54) by way of the integrated liquid pipe
(53), the heat source-side liquid pipe (62), and the liquid
refrigerant inflow passageway (66). Therefore, it becomes possible
to prevent the high pressure of the compression mechanism (11D,
11E) from increasing too much. Accordingly, if it is arranged such
that prior to activation of the pressure switch (HPS) for high
pressure protection the switch valve (SV1) is placed in the opened
state, this makes it possible to prevent the refrigeration
apparatus from malfunctioning to stop operating due to shutdown of
the compression mechanism (11D, 11E).
[0037] In the case where the second utilization-side units (20) are
connected in parallel to the heat source-side unit (10), the
discharge pressure of the compression mechanism (11D, 11E) tends to
increase if there is a second utilization-side unit (20) that is
placed in the thermo-off state and in addition the refrigeration
apparatus tends to stop operating because of activation of the
pressure switch for high pressure protection. However, according to
the second aspect of the present invention, placing the switch
valve (SV1) in the opened state prior to activation of the pressure
switch may ensure that the malfunction of the refrigeration
apparatus is prevented from occurring.
[0038] In the refrigeration apparatus according to the third aspect
of the present invention having the first system-side circuit (50A)
in which refrigerant is circulated between the heat source-side
unit (10) and the first utilization-side unit (30, 40) in one
direction to thereby provide compartment cooling and the second
system-side circuit (50A) in which refrigerant is circulated
reversibly between the heat source-side unit (10) and the second
utilization-side unit (20) to thereby provide indoor air
conditioning, the discharge pressure of the compression mechanism
(11D, 11E) is prevented from increasing too much by placing the
switch valve (SV1) in the opened state during the 100% heat
recovery operation mode in which the second utilization-side heat
exchanger (21) and the first utilization-side heat exchanger (31,
41) function, respectively, as a condenser and as an evaporator,
even if the operation capacity of the compression mechanism (11D,
11E) is increased when there is excess refrigerant in the second
utilization-side heat exchanger (21) and the liquid-side interunit
piping line (53, 54, 55). Accordingly, as in the first and second
aspects of the present invention, it is ensured that the
refrigeration apparatus is prevented from malfunction.
[0039] According to the fourth aspect of the present invention, by
virtue of the provision of the control means (95) capable of on-off
control of the switch valve (SV1) in response to the operation
state, it becomes possible to prevent the occurrence of operation
problems in the 100% heat recovery operation mode or other
operation mode.
[0040] According to the fifth aspect of the present invention, in
the operation state in which the second utilization-side heat
exchanger (21) and the first utilization-side heat exchanger (31,
41) function, respectively, as a condenser and an evaporator, the
switch valve (SV1) is placed in the closed state if the discharge
pressure of the compression mechanism (11D, 11E) is below the
predetermined value while on the other hand the switch valve (SV1)
is placed in the opened state if the discharge pressure of the
compression mechanism (11D, 11E) increases to equal or exceed the
predetermined value. Therefore, during the 100% heat recovery
operation mode, the switch valve (SV1) is placed in the closed
state under normal conditions whereby the refrigeration apparatus
operates wherein the quantity of heat of condensation of the second
utilization-side heat exchanger (21) and the quantity of heat of
evaporation of the first utilization-side heat exchanger (31, 41)
are in balance with each other. On the other hand, since it is
possible to permit escape of high pressure refrigerant between the
second utilization-side heat exchanger (21) and the liquid-side
interunit piping line (53, 54, 55) into the receiver (17) by
placing the switch valve (SV1) in the opened state if the discharge
pressure of the compression mechanism (11D, 11E) reaches the
predetermined value or above, it becomes possible to prevent the
problem that causes the refrigeration apparatus to stop operating
by setting the set pressure of the switch valve (SV1) at which it
is placed in the opened state to fall below the working pressure of
the pressure switch for high pressure protection.
[0041] According to the sixth aspect of the present invention, in
the operation state in which the second utilization-side heat
exchanger (21) and the first utilization-side heat exchanger (31,
41) function, respectively, as a condenser and an evaporator, the
switch valve (SV1) is placed in the closed state if the amount of
liquid refrigerant accumulated in the second utilization-side heat
exchanger (21) and the liquid-side interunit piping line (53, 54,
55) is below the predetermined value while on the other hand the
switch valve (SV1) is placed in the opened state if it is estimated
that the liquid refrigerant amount accumulated reaches the
predetermined value or above. Therefore, during the 100% heat
recovery operation mode, the switch valve (SV1) is placed in the
closed state under normal conditions whereby the refrigeration
apparatus operates wherein the quantity of heat of condensation of
the second utilization-side heat exchanger (21) and the quantity of
heat of evaporation of the first utilization-side heat exchanger
(31, 41) are in balance with each other. On the other hand, it is
possible to permit escape of high pressure refrigerant between the
second utilization-side heat exchanger (21) and the liquid-side
interunit piping line (53, 54, 55) into the receiver (17) by
placing the switch valve (SV1) in the opened state if it is
estimated that the liquid refrigerant amount accumulated reaches
the predetermined value or above. This therefore makes it possible
to prevent excess accumulation of liquid refrigerant in the second
utilization-side heat exchanger (21) and the liquid-side interunit
piping line (53, 54, 55), and it becomes also possible to prevent
the refrigeration apparatus from malfunctioning to stop operating
due to the discharge pressure of the compression mechanism (11D,
11E) increasing too much.
[0042] According to the seventh aspect of the present invention, in
the operation state in which the second utilization-side heat
exchanger (21) and the first utilization-side heat exchanger (31,
41) function, respectively, as a condenser and an evaporator, the
switch valve (SV1) is placed in the closed state if the temperature
of liquid refrigerant in the second utilization-side heat exchanger
(21) is below the predetermined value while on the other hand the
switch valve (SV1) is placed in the opened state if the liquid
refrigerant temperature increases to equal or exceed the
predetermined value. Therefore, during the 100% heat recovery
operation mode, the switch valve (SV1) is placed in the closed
state under normal conditions whereby the refrigeration apparatus
operates wherein the quantity of heat of condensation of the second
utilization-side heat exchanger (21) and the quantity of heat of
evaporation of the first utilization-side heat exchanger (31, 41)
are in balance with each other. On the other hand, since it is
possible to permit escape of high pressure refrigerant between the
second utilization-side heat exchanger (21) and the liquid-side
interunit piping line (53, 54, 55) into the receiver (17) by
placing the switch valve (SV1) in the opened state if the liquid
refrigerant temperature increases to equal or exceed the
predetermined value, it becomes possible to prevent the problem
that causes the compression mechanism (11D, 11E) to stop operating
by setting the pressure derived from the set temperature of the
switch valve (SV1) at which it is placed in the opened state to
fall below the working pressure of the pressure switch for high
pressure protection.
[0043] According to the eighth aspect of the present invention, in
the operation state in which the second utilization-side heat
exchanger (21) and the first utilization-side heat exchanger (31,
41) function, respectively, as a condenser and an evaporator, the
switch valve (SV1) is placed in the closed state if the pressure of
liquid refrigerant in the liquid-side interunit piping line (53,
54, 55) is below the predetermined value while on the other hand
the switch valve (SV1) is placed in the opened state if the liquid
refrigerant pressure increases to equal or exceed the predetermined
value. Therefore, during the 100% heat recovery operation mode, the
switch valve (SV1) is placed in the closed state under normal
conditions whereby the refrigeration apparatus operates wherein the
quantity of heat of condensation of the second utilization-side
heat exchanger (21) and the quantity of heat of evaporation of the
first utilization-side heat exchanger (31, 41) are in balance with
each other. On the other hand, since it is possible to permit
escape of high pressure refrigerant in the liquid-side interunit
piping line (53, 54, 55) into the receiver (17) by placing the
switch valve (SV1) in the opened state if the liquid refrigerant
pressure increases to equal or exceed the predetermined value, it
becomes possible to prevent the problem that causes the compression
mechanism (11D, 11E) to stop operating by setting the pressure
derived from the set temperature of the switch valve (SV1) at which
it is placed in the opened state to fall below the working pressure
of the pressure switch for high pressure protection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] In the accompanying drawings:
[0045] FIG. 1 is a refrigerant circuit diagram of a refrigeration
apparatus according to an embodiment of the present invention;
[0046] FIG. 2 is a refrigerant circuit diagram illustrating a
cooling operation mode in the embodiment;
[0047] FIG. 3 is a refrigerant circuit diagram illustrating a
refrigeration operation mode in the embodiment;
[0048] FIG. 4 is a refrigerant circuit diagram illustrating a first
cooling/refrigeration operation mode in the embodiment;
[0049] FIG. 5 is a refrigerant circuit diagram illustrating a
second cooling/refrigeration operation mode in the embodiment;
[0050] FIG. 6 is a refrigerant circuit diagram illustrating a
heating operation mode in the embodiment;
[0051] FIG. 7 is a refrigerant circuit diagram illustrating a first
heating/refrigeration operation mode in the embodiment;
[0052] FIG. 8 is a refrigerant circuit diagram illustrating a
second heating/refrigeration operation mode in the embodiment;
[0053] FIG. 9 is a refrigerant circuit diagram illustrating a third
heating/refrigeration operation mode in the embodiment; and
[0054] FIG. 10 is a refrigerant circuit diagram of a conventional
refrigeration apparatus.
DESCRIPTION OF THE REFERENCE NUMERALS
[0055] 1: refrigeration apparatus [0056] 10: outdoor unit (heat
source-side unit) [0057] 11D: compression mechanism [0058] 11E:
compression mechanism [0059] 15: outdoor heat exchanger (heat
source-side heat exchanger) [0060] 17: receiver [0061] 20: indoor
unit (second utilization-side unit) [0062] 21: indoor heat
exchanger (second utilization-side heat exchanger) [0063] 30: cold
storage unit (first utilization-side unit) [0064] 31: cold storage
heat exchanger (first utilization-side heat exchanger) [0065] 40:
freeze storage unit (first utilization-side unit) [0066] 41: freeze
storage heat exchanger (first utilization-side heat exchanger)
[0067] 50: refrigerant circuit [0068] 50A: first system-side
circuit [0069] 50B: second system-side circuit [0070] 51: first
gas-side interunit piping line (gas-side interunit piping line)
[0071] 52: second gas-side interunit piping line (gas-side
interunit piping line) [0072] 53: integrated liquid pipe
(liquid-side interunit piping line) [0073] 54: first branch liquid
pipe (liquid-side interunit piping line) [0074] 55: second branch
liquid pipe (liquid-side interunit piping line) [0075] 62: outdoor
liquid pipe (heat source-side liquid pipe) [0076] 66: liquid
refrigerant inflow passageway [0077] 95: control means [0078] SV1:
solenoid valve (switch valve)
BEST MODE FOR CARRYING OUT THE INVENTION
[0079] In the following, preferred embodiments of the present
invention will be described in detail with reference to the
drawings.
[0080] FIG. 1 is a refrigerant circuit diagram of a refrigeration
apparatus (1) according to an embodiment of the present invention.
The refrigeration apparatus (1) is installed, for example, in a
convenience store and provides cooling of a showcase used for cold
storage, cooling of a showcase used for freeze storage, and
cooling/heating of the store space.
[0081] The refrigeration apparatus (1) includes these units: an
outdoor unit (heat source-side unit) (10), an indoor unit (second
utilization-side unit) (20), a cold storage unit (first
utilization-side unit) (30), and a freeze storage unit (first
utilization-side unit) (40). These units (10, 20, 30, 40) are
connected by a gas-side interunit piping line (51, 52) and a
liquid-side interunit piping line (53, 54, 55) to constitute a
refrigerant circuit (50) in which a vapor compression refrigeration
cycle is performed.
[0082] The gas-side interunit piping line (51, 52) is made up of a
first gas-side interunit piping line (low pressure gas pipe) (51)
and a second gas-side interunit piping line (52). The first
gas-side interunit piping line (51) is connected to the outdoor
unit (10), the cold storage unit (30), and the freeze storage unit
(40). The second gas-side interunit piping line (52) is connected
to the outdoor unit (10) and the indoor unit (20). On the other
hand, the liquid-side interunit piping line (53, 54, 55) is made up
of an integrated liquid pipe (53), a first branch liquid pipe (54),
and a second branch liquid pipe (55). The integrated liquid pipe
(53) is connected to the outdoor unit (10). The first branch liquid
pipe (54) is a branch pipe diverged from the integrated liquid pipe
(53) for connection to the cold storage unit (30) and the freeze
storage unit (40). The second branch liquid pipe (55) is also a
branch pipe diverged from the integrated liquid pipe (53) for
connection to the indoor unit (20). Also note that the first branch
liquid pipe (54) is made up of a cold storage-side first branch
liquid pipe (54a) on the side of the cold storage unit (30) and a
freeze storage-side first branch liquid pipe (54b) on the side of
the freeze storage unit (40). In the present embodiment, the
integrated liquid pipe (53) which is a portion of the liquid-side
interunit piping line (53, 54, 55) on the side of the outdoor unit
(10) is shared between the indoor unit (20) and the cold and freeze
storage units (30, 40), in other words, the present embodiment
employs an interunit piping line configuration of the three-pipe
system.
[0083] The indoor unit (20) is configured switchably between a
cooling operation mode and a heating operation mode and is
installed, for example, in a store selling space or the like. In
addition, the cold storage unit (30) is placed in a showcase used
for cold storage and provides cooling of compartment air in the
cold storage showcase. The freeze storage unit (40) is placed in a
showcase used for freeze storage and provides cooling of
compartment air in the freeze storage showcase. In the present
embodiment, two indoor units (20) are connected in parallel, eight
cold storage units (30) are connected in parallel, and a single
freeze storage unit (40) is connected. However, for the sake of
simplicity there are only shown in the figure one of the two indoor
units (20), one of the eight cold storage units (30), and the one
freeze storage unit (40).
[0084] And, the refrigerant circuit (50) includes a first
system-side circuit (50A) used to provide cold/freeze storage and a
second system-side circuit (50B) used to provide air conditioning.
The first system-side circuit (50A) is made up of the outdoor unit
(10) which is a heat source-side unit, the cold storage unit (30)
which is a first utilization-side unit, and the freeze storage unit
(40) which is a first utilization-side unit, and refrigerant is
circulated in one direction therein. On the other hand, the second
system-side circuit (50B) is made up of the outdoor unit (10) which
is a heat source-side unit and the indoor unit (20) which is a
second utilization-side unit, and refrigerant is circulated
reversibly therein.
Outdoor Unit
[0085] The outdoor unit (10) is provided with an inverter
compressor (11A) as a first compressor, a first non-inverter
compressor (11B) as a second compressor, and a second non-inverter
compressor (11C) as a third compressor. In addition to these
compressors, the outdoor unit (10) further includes a first
four-way valve (12), a second four-way valve (13), a third four-way
valve (14), and an outdoor heat exchanger (15) which is a heat
source-side heat exchanger. Also note that the outdoor heat
exchanger (15) is, for example, a fin and tube heat exchanger of
the cross fin type, and an outdoor fan (16) which is a heat source
fan is disposed in vicinity to the outdoor heat exchanger (15).
[0086] The compressors (11A, 11B, 11C) are each formed, for
example, by a hermetic, high pressure dome type scroll compressor.
The inverter compressor (11A) is a variable capacity compressor the
capacity of which can be gradually or continuously variable by
inverter control of an electric motor. Each of the first and second
non-inverter compressors (11B, 11C) is a fixed displacement
compressor which is driven by an electric motor constantly at a
fixed speed of rotation.
[0087] The inverter compressor (11A), the first non-inverter
compressor (11B), and the second non-inverter compressor (11C)
together constitute a compression mechanism (11D, 11E) of the
refrigeration apparatus (1). The compression mechanism (11D, 11E)
is made up of a compression mechanism (11D) of a first system and a
compression mechanism (11E) of a second system. More specifically,
the compression mechanism (11D, 11E) when in operation is
configured as follows. On one hand, the inverter compressor (11A)
and the first non-inverter compressor (11B) together constitute the
compression mechanism (11D) of the first system while the second
non-inverter compressor (11C) alone constitutes the compression
mechanism (11E) of the second system. On the other hand, the
inverter compressor (11A) alone constitutes the compression
mechanism (11D) of the first system while the first non-inverter
compressor (11B) and the second non-inverter compressor (11C)
together constitute the compression mechanism (11E) of the second
system. Stated another way, the inverter compressor (11A) is used
fixedly by the first system-side circuit (50A) for cold/freeze
storage and the second non-inverter compressor (11c) is used
fixedly by the second system side circuit (50B) for air
conditioning while the first non-inverter compressor (11B) can be
used selectively by either the first system-side circuit (50A) or
the second system-side circuit (50B).
[0088] The inverter compressor (11A), the first non-inverter
compressor (11B), and the second non-inverter compressor (11C) have
respective discharge pipes (56a, 56b, 56c) which are connected to a
single high pressure gas pipe (discharge piping line) (57). The
discharge pipe (56b) of the first non-inverter compressor (11B) is
provided with a check valve (CV1). The discharge pipe (56c) of the
second non-inverter compressor (11C) is provided with a check valve
(CV2).
[0089] The high pressure gas pipe (57) is connected to a first port
(P1) of the first four-way valve (12). The gas-side end of the
outdoor heat exchanger (15) is connected to a second port (P2) of
the first four-way valve (12) by an outdoor first gas pipe (58a).
The second gas-side interunit piping line (52) is connected through
an outdoor second gas pipe (58b) to a third port (P3) of the first
four-way valve (12). A fourth port (P4) of the first four-way valve
(12) is connected to the second four-way valve (13).
[0090] A first port (P1) of the second four-way valve (13) is
connected to the discharge pipe (56c) of the second non-inverter
compressor (11C) by an auxiliary gas pipe (59). A second port (P2)
of the second four-way valve (13) is a closed port, in other word
the second port (P2) is blocked. A third port (P3) of the second
four-way valve (13) is connected to the fourth port (P4) of the
first four-way valve (12) by a connection pipe (60). In addition, a
suction pipe (61c) of the second non-inverter compressor (11C) is
connected to a fourth port (P4) of the second four-way valve (13).
Since the second port (P2) of the second four-way valve (13) is a
closed port, this may allow use of a three-way valve as a
substitute for the second four-way valve (13).
[0091] The first four-way valve (12) is configured such that it is
switchable between (i) a first state (see solid line representation
in the figure) that allows fluid communication between the first
port (P1) and the second port (P2), and between the third port (P3)
and the fourth port (P4) and (ii) a second state (see broken line
representation in the figure) that allows fluid communication
between the first port (P1) and the third port (P3), and between
the second port (P2) and the fourth port (P4).
[0092] Likewise, the second four-way valve (13) is configured such
that it is switchable between (i) a first state (see solid line
representation in the figure) that allows fluid communication
between the first port (P1) and the second port (P2), and between
the third port (P3) and the fourth port (P4) and (ii) a second
state (see broken line representation in the figure) that allows
fluid communication between the first port (P1) and the third port
(P3), and between the second port (P2) and the fourth port
(P4).
[0093] One end of an outdoor liquid pipe (heat source-side liquid
pipe) (62) which is a liquid line is connected to the liquid-side
end of the outdoor heat exchanger (15). A receiver (17) for storing
therein liquid refrigerant is disposed along the outdoor liquid
pipe (62), and the other end of the outdoor liquid pipe (62) is
connected to the integrated liquid pipe (53) of the liquid-side
interunit piping line (53, 54, 55).
[0094] The receiver (17) is connected to the outdoor liquid pipe
(62) through these pipes: a first inflow pipe (63a) which allows
inflow of refrigerant from the outdoor heat exchanger (15), a first
outflow pipe (63b) which allows outflow of refrigerant to the
liquid-side interunit piping line (53, 54, 55), a second inflow
pipe (liquid refrigerant inflow passageway) (63c) which allows
inflow of refrigerant from the liquid-side interunit piping line
(53, 54, 55), and a second outflow pipe (63d) which allows outflow
of refrigerant to the outdoor heat exchanger (15).
[0095] A suction pipe (61a) of the inverter compressor (11A) is
connected through a low pressure gas pipe (64) of the first
system-side circuit (50A) to the low pressure gas-side interunit
piping line (51). A suction pipe (61c) of the second non-inverter
compressor (11C) is connected through the first and second four-way
valves (12, 13) to a low pressure gas pipe (either the outdoor
second gas pipe (58b) or the outdoor first gas pipe (58a)) of the
second system-side circuit (50B). In addition, a suction pipe (61b)
of the first non-inverter compressor (11B) is connected through the
third four-way valve (14) to the suction pipe (61a) of the inverter
compressor (11A) and to the suction pipe (61c) of the second
non-inverter compressor (11C).
[0096] More specifically, a branch pipe (61d) is connected to the
suction pipe (61a) of the inverter compressor (11A) and a branch
pipe (61e) is connected to the suction pipe (61c) of the second
non-inverter compressor (11C). And the branch pipe (61d) of the
suction pipe (61a) of the inverter compressor (11A) is connected
through a check valve (CV3) to the first port (P1) of the third
four-way valve (14); the suction pipe (61b) of the first
non-inverter compressor (11B) is connected to the second port (P2)
of the third four-way valve (14); and the branch pipe (61e) of the
suction pipe (61c) of the second non-inverter compressor (11C) is
connected through a check valve (CV4) to the third port (P3) of the
third four-way valve (14). The check valves (CV3, CV4) disposed
respectively in the branch pipes (61d, 61e) permit only flow of
refrigerant in the direction of the third four-way valve (14) while
stopping reverse refrigerant flow. In addition, a high pressure
introduction pipe (not shown) for introduction of the high pressure
of the refrigerant circuit (50) is connected to the fourth port
(P4) of the third four-way valve (14).
[0097] The third four-way valve (14) is configured such that it is
switchable between (i) a first state (see solid line representation
in the figure) that allows fluid communication between the first
port (P1) and the second port (P2), and between the third port (P3)
and the fourth port (P4) and (ii) a second state (see broken line
representation in the figure) that allows fluid communication
between the first port (P1) and the fourth port (P4), and between
the second port (P2) and the third port (P3).
[0098] The first and second gas-side interunit piping lines (51,
52), and the integrated liquid pipe (53) of the liquid-side
interunit piping line (53, 54, 55) are extended outside from the
outdoor unit (10), and their associated stop valves (18a, 18b, 18c)
are disposed within the outdoor unit (10).
[0099] Connected to the outdoor liquid pipe (62) is an auxiliary
liquid pipe (65) (the second outflow pipe (63d)) which bypasses the
receiver (17). Refrigerant flows through the auxiliary liquid pipe
(65), mainly during the heating operation mode. The auxiliary
liquid pipe (65) is provided with an outdoor expansion valve (19)
which is an expansion mechanism. A check valve (CV5) which permits
only flow of refrigerant in the direction of the receiver (17) is
disposed between the outdoor heat exchanger (15) and the receiver
(17) in the outdoor liquid pipe (62), in other words the check
valve (CV5) is disposed in the first inflow pipe (63a). The check
valve (CV5) is positioned between a part of connection with the
auxiliary liquid pipe (65) and the receiver (17) in the outdoor
liquid pipe (62).
[0100] The outdoor liquid pipe (62) is diverged between the check
valve (CV5) and the receiver (17) into a liquid branch pipe (66)
(the second inflow pipe (63c)), and is connected to between the
stop valve (18c) and a check valve (CV7) (to be described later) in
the outdoor liquid pipe (62). The liquid branch pipe (66) is
provided with a check valve (CV6) which permits flow of refrigerant
towards the receiver (17) from a point of connection with the
outdoor liquid pipe (62) between the stop valve (18c) and the check
valve (CV7).
[0101] The liquid branch pipe (66) (the second inflow pipe (63c))
is a liquid refrigerant inflow passageway which is connected to the
outdoor liquid pipe (62) which is connected to the integrated
liquid pipe (53) of the liquid-side interunit piping line (53, 54,
55), and to the inlet port of the receiver (17). The liquid
refrigerant inflow passageway (66) is provided with a solenoid
valve (switch valve) (SV1) capable of being on-off controlled. The
solenoid valve (SV1) is disposed between a point of connection with
the outdoor liquid pipe (62) in the liquid branch pipe (66) and the
check valve (CV6).
[0102] The outdoor liquid pipe (62) is provided, between a point of
connection with the auxiliary liquid pipe (65) and the stop valve
(18c), with the check valve (CV7), in other words the check valve
(CV7) is disposed in the first outflow pipe (63b). The check valve
(CV7) permits only flow of refrigerant towards the stop valve (18c)
from the receiver (17).
[0103] A liquid injection pipe (67) is connected to the liquid
branch pipe (66) (the second inflow pipe (63c)) and to the low
pressure gas pipe (64). One end of the liquid injection pipe (67)
is connected between a point of connection with the outdoor liquid
pipe (62) and the solenoid valve (SV1) to the liquid branch pipe
(66) (the second inflow pipe (63c)). In addition, the other end of
the liquid injection pipe (67) is connected between the suction
pipe (61a) of the inverter compressor (11A) and the stop valve
(18a) to the low pressure gas pipe (64). The liquid injection pipe
(67) is provided with a motor-operated expansion valve (67a) for
flow rate control.
Indoor Unit
[0104] The indoor unit (20) is provided with an indoor heat
exchanger (air conditioning heat exchanger) (21) which is a second
utilization-side heat exchanger and an indoor expansion valve (22)
which is an expansion mechanism. The second gas-side interunit
piping line (52) is connected to the gas side of the indoor heat
exchanger (21). On the other hand, the second branch liquid pipe
(55) of the liquid-side interunit piping line (53, 54, 55) is
connected through the indoor expansion valve (22) to the liquid
side of the indoor heat exchanger (21). Also note that the indoor
heat exchanger (21) is, for example, a fin and tube heat exchanger
of the cross fin type, and an indoor fan (23) which is a
utilization-side fan is disposed in vicinity to the indoor heat
exchanger (21). In addition, the indoor expansion valve (22) is
formed by a motor-operated expansion valve.
Cold Storage Unit
[0105] The cold storage unit (30) is provided with a cold storage
heat exchanger (31) which is a first utilization-side heat
exchanger (evaporator) and a cold storage expansion valve (32)
which is an expansion mechanism. The first branch liquid pipe (54)
(the cold storage-side first branch liquid pipe (54a)) of the
liquid-side interunit piping line (53, 54, 55) is connected through
the cold storage expansion valve (32) and then through a solenoid
valve (SV2) to the liquid side of the cold storage heat exchanger
(31). The solenoid valve (SV2) is employed to stop flow of
refrigerant during the thermo-off (rest) operation mode. On the
other hand, a cold storage-side branch gas pipe (51a) diverged from
the first gas-side interunit piping line (51) is connected to the
gas side of the cold storage heat exchanger (31).
[0106] The cold storage heat exchanger (31) is in fluid
communication with the suction side of the inverter compressor
(11A) while on the other hand the indoor heat exchanger (21) is in
fluid communication with the suction side of the second
non-inverter compressor (11C) during the cooling operation mode.
The refrigerant pressure (evaporation pressure) of the cold storage
heat exchanger (31) is lower than the refrigerant pressure
(evaporation pressure) of the indoor heat exchanger (21). More
specifically, the refrigerant evaporation temperature of the cold
storage heat exchanger (31) is, for example, minus 10 degrees
Centigrade and the refrigerant evaporation temperature of the
indoor heat exchanger (21) is, for example, plus 5 degrees
Centigrade, and the refrigerant circuit (50) constitutes a circuit
in which refrigerant is evaporated at different temperatures.
[0107] Also note that the cold storage expansion valve (32) is a
temperature-sensitive expansion valve and its temperature sensing
bulb is mounted at the gas side of the cold storage heat exchanger
(31). Accordingly, the degree of opening of the cold storage
expansion valve (32) is controlled based on the temperature of
refrigerant at the outlet side of the cold storage heat exchanger
(31). The cold storage heat exchanger (31) is, for example, a fin
and tube heat exchanger of the cross fin type, and a cold storage
fan (33) which is a cooling fan is disposed in vicinity to the cold
storage heat exchanger (31).
Freeze Storage Unit
[0108] The freeze storage unit (40) is provided with a freeze
storage heat exchanger (41) which is a first utilization-side heat
exchanger, a freeze storage expansion valve (42) which is an
expansion mechanism, and a booster compressor (43) which is a
freeze storage compressor. The first branch liquid pipe (54) (the
freeze storage-side first branch liquid pipe (54b)) of the
liquid-side interunit piping line (53, 54, 55) is connected through
the freeze storage expansion valve (42) and then through the
solenoid valve (SV3) to the liquid side of the freeze storage heat
exchanger (41).
[0109] The gas side of the freeze storage heat exchanger (41) and
the suction side of the booster compressor (43) are connected
together by a connection gas pipe (68). Connected to the discharge
side of the booster compressor (43) is the freeze storage-side
branch gas pipe (51b) diverged from the first gas-side interunit
piping line (51). The freeze storage-side branch gas pipe (51b) is
provided with a check valve (CV8) and an oil separator (44).
Connected to between the oil separator (44) and the connection gas
pipe (68) is an oil return pipe (69) having a capillary tube
(45).
[0110] In order that the refrigerant evaporation temperature of the
freeze storage heat exchanger (41) may fall below the refrigerant
evaporation temperature of the cold storage heat exchanger (31),
the booster compressor (43) performs, together with the compression
mechanism (11D) of the first system, two-stage compression of
refrigerant. It is set such that the refrigerant evaporation
temperature of the freeze storage heat exchanger (41) is, for
example, minus 35 degrees Centigrade.
[0111] Also note that the freeze storage expansion valve (42) is a
temperature-sensitive expansion valve and its temperature sensing
bulb is mounted at the gas side of the freeze storage heat
exchanger (41). The freeze storage heat exchanger (41) is, for
example, a fin and tube heat exchanger of the cross fin type, and a
freeze storage fan (46) which is a cooling fan is disposed in
vicinity to the freeze storage heat exchanger (41).
[0112] In addition, a bypass pipe (70) having a check valve (CV9)
is connected to the connection gas pipe (68) which is the suction
side of the booster compressor (43), and to between the oil
separator (44) and the check valve (CV8) in the freeze storage-side
branch gas pipe (51b). The bypass pipe (70) is configured such that
refrigerant is allowed to flow, bypassing the booster compressor
(43) during the shutdown time (for example, when the booster
compressor (43) fails to operate properly).
Control System
[0113] The refrigerant circuit (50) is provided with various
sensors and various switches. The high pressure gas pipe (57) of
the outdoor unit (10) is provided with a high pressure sensor (75)
which is a pressure detector means for detection of the pressure of
high pressure refrigerant, and a discharge temperature sensor (76)
which is a temperature detector means for detection of the
temperature of high pressure refrigerant. The discharge pipe (56c)
of the second non-inverter compressor (11C) is provided with a
discharge temperature sensor (77) which is a temperature detector
means for detection of the temperature of high pressure
refrigerant. In addition, the discharge pipe (56a) of the inverter
compressor (11A), the discharge pipe (56b) of the first
non-inverter compressor (11B), and the discharge pipe (56c) of the
second non-inverter compressor (11C) are each provided with a
respective pressure switch (78) for high pressure protection which
is placed in the opened state to stop its associated one of the
compressors (11A, 11B, 11C) whenever the pressure of high pressure
refrigerant reaches a predetermined value.
[0114] The suction pipe (61a) of the inverter compressor (11A) is
provided with a low pressure sensor (79) which is a pressure
detector means for detection of the pressure of low pressure
refrigerant, and a suction temperature sensor (81) which is a
temperature detector means for detection of the temperature of low
pressure refrigerant. Likewise, the suction pipe (61c) of the
second non-inverter compressor (11C) is provided with a low
pressure sensor (80) and a suction temperature sensor (82).
[0115] The outdoor heat exchanger (15) is provided with an outdoor
heat exchange sensor (83) which is a temperature detector means for
detection of the temperature of evaporation or condensation which
is the temperature of refrigerant in the outdoor heat exchanger
(15). In addition, the outdoor unit (10) is provided with an
outside air temperature sensor (84) which is a temperature detector
means for detection of the temperature of outdoor air.
[0116] The indoor heat exchanger (21) is provided with an indoor
heat exchange sensor (85) which is a temperature detector means for
detection of the temperature of evaporation or condensation which
is the temperature of refrigerant in the indoor heat exchanger
(21). The indoor heat exchanger (21) is also provided, at its gas
side, with a gas temperature sensor (86) which is a temperature
detector means for detection of the temperature of gas refrigerant.
In addition, the indoor unit (20) is provided with a room
temperature sensor (87) which is a temperature detector means for
detection of the temperature of indoor air.
[0117] The cold storage unit (30) is provided with a cold storage
temperature sensor (88) which is a temperature detector means for
detection of the compartment temperature of the cold storage
showcase. The freeze storage unit (40) is provided with a freeze
storage temperature sensor (89) which is a temperature detector
means for detection of the compartment temperature of the freeze
storage showcase. In addition, the booster compressor (43) has, at
its discharge side, a pressure switch (90) for high pressure
protection which is placed in the opened state to stop the booster
compressor (43) whenever the pressure of discharge refrigerant
reaches a predetermined value.
[0118] Output signals from these various sensors and switches are
fed to a controller (control means) (95). The controller (95) is
configured such that it controls the operation of the refrigerant
circuit (50) whereby the refrigerant circuit (50) is operated
selectively in either one of eight different operation modes (to be
described later). And, in operation, the controller (95) provides:
control of the start, stop, and capacity of the inverter compressor
(11A); control of the start and stop of the first and second
non-inverter compressors (11B, 11C); and control of the adjustment
of the degree of opening of the outdoor and indoor expansion valves
(19, 22). In addition, the controller (95) provides control of the
switching of each of the four-way valves (12, 13, 14) and control
of the degree of opening of the motor-operated expansion valve
(67a) of the liquid injection pipe (67).
[0119] The controller (95) provides also control of the on-off of
the solenoid valve (SV1) of the liquid branch pipe (66) which is a
liquid refrigerant inflow passageway in response to the operation
state. More specifically, the controller (95) provides the
following control when performing, without the use of the outdoor
heat exchanger (15), a heating operation mode of 100% heat recovery
in which the indoor heat exchanger (21) functions as a condenser
and the cold and freeze storage heat exchangers (31, 42) function
as evaporators.
[0120] In the first place, during the 100% heat recovery heating
operation mode, the controller (95) performs the following control
on the solenoid valve (SV1). That is, when the discharge pressure
of the compression mechanism (11D, 11E) is below a predetermined
value, the solenoid valve (SV1) is placed in the closed state. On
the other hand, when the discharge pressure of the compression
mechanism (11D, 11E) increases to equal or exceed the predetermined
value, the solenoid valve (SV1) is placed in the opened state. In
addition, during the 100% heat recovery heating operation mode, the
controller (95) further performs the following control on the
solenoid valve (SV1). That is, when the amount of liquid
refrigerant accumulated in the indoor heat exchanger (21) and the
liquid-side interunit piping line (53, 54, 55) is below a
predetermined value, the solenoid valve (SV1) is placed in the
closed state. On the other hand, when it is estimated that the
liquid refrigerant amount accumulated reaches the predetermined
value or above, the solenoid valve (SV1) is placed in the opened
state. Furthermore, during the 100% heat recovery heating operation
mode, the controller (95) provides the following control on the
solenoid valve (SV1). That is, when the temperature of liquid
refrigerant in the indoor heat exchanger (21) is below a
predetermined value, the solenoid valve (SV1) is placed in the
closed state. On the other hand, when the liquid refrigerant
temperature increases to equal or exceed the predetermined value,
the solenoid valve (SV1) is placed in the opened state. Besides,
during the 100% heat recovery heating operation mode, the
controller (95) performs the following control on the solenoid
valve (SV1). That is, when the pressure of liquid refrigerant in
the liquid-side interunit piping line (53, 54, 55) is below a
predetermined value, the solenoid valve (SV1) is placed in the
closed state. On the other hand, when the liquid refrigerant
pressure increases to equal or exceed the predetermined value, the
solenoid valve (SV1) is placed in the opened state.
[0121] Also note that during the cooling operation mode (to be
described later) and when the compression mechanism (11D, 11E) is
placed at rest, the controller (95) provides control so that the
solenoid valve (SV1) is placed in the closed state. In addition,
during the heating operation mode in which the outdoor heat
exchanger (15) is used as an evaporator, the controller (95)
provides control so that the solenoid valve (SV1) is placed in the
opened state.
Running Operation
[0122] Next, description will be made regarding each of operation
modes of the running operation of the refrigeration apparatus (1).
The refrigeration apparatus (1) is configured such that it is
selectively settable to operate in either one of, for example,
eight different operation modes, in the present embodiment. More
specifically, the refrigeration apparatus (1) is so configured as
to be able to selectively perform:
(i) a cooling operation mode that provides only indoor space
cooling by the indoor unit (20); (ii) a refrigeration operation
mode that provides only compartment cooling by the cold and freeze
storage units (30, 40); (iii) a first cooling/refrigeration
operation mode that provides indoor space cooling by the indoor
unit (20) simultaneously with compartment cooling by the cold and
freeze storage units (30, 40); (iv) a second cooling/refrigeration
operation mode that is performed if the cooling capacity of the
indoor unit (20) is insufficient in the first cooling/refrigeration
operation mode; (v) a heating operation mode that provides only
indoor space heating by the indoor unit (20); (vi) a first
heating/refrigeration operation mode that provides, without the use
of the outdoor heat exchanger (15), indoor space heating by the
indoor unit (20) and compartment cooling by the cold and freeze
storage units (30, 40) with 100% heat recovery; (vii) a second
heating/refrigeration operation mode that is performed if the
heating capacity of the indoor unit (20) is in surplus in the first
heating/refrigeration operation mode; or (viii) a third
heating/refrigeration operation mode that is performed if the
heating capacity of the indoor unit (20) is insufficient in the
first heating/refrigeration operation mode.
[0123] In the following, each of the above operation modes is
described more specifically.
Cooling Operation Mode
[0124] The cooling operation mode is an operation mode that
provides only indoor space cooling by the indoor unit (20). During
the cooling operation mode, the inverter compressor (11A) alone
constitutes the compression mechanism (11D) of the first system
while the first non-inverter compressor (11B) and the second
non-inverter compressor (11C) together constitute the compression
mechanism (11E) of the second system, as shown in FIG. 2. And, only
the first and second non-inverter compressors (11B, 11C), i.e., the
compression mechanism (11E) of the second system, are
activated.
[0125] In addition, as indicated by solid line representation in
FIG. 2, the first and second four-way valves (12, 13) each change
state to the first state while, on the other hand, the third
four-way valve (14) changes states to the second state. In
addition, the outdoor expansion valve (19), the motor-operated
expansion valve (67a) of the liquid injection pipe (67), the
solenoid valve (SV1) of the liquid branch pipe (66) (the second
inflow pipe (63c)) which is a liquid refrigerant inflow passageway,
the solenoid valve (SV2) of the cold storage unit (30), and the
solenoid valve (SV3) of the freeze storage unit (40) are all placed
in the closed state.
[0126] In this state, discharged refrigerant from the first and
second non-inverter compressors (11B, 11C) flows through the first
four-way valve (12) and then through the outdoor first gas pipe
(58a) into the outdoor heat exchanger (15), and is condensed to
liquid refrigerant. The condensed liquid refrigerant flows through
the outdoor liquid pipe (62), passes through the receiver (17),
then through the integrated liquid pipe (53) of the liquid-side
interunit piping line (53, 54, 55), and then through the second
branch liquid pipe (55), enters the indoor heat exchanger (21) by
way of the indoor expansion valve (22), and is evaporated to gas
refrigerant. The evaporated gas refrigerant passes through the
second gas-side interunit piping line (52), then through the
outdoor second gas pipe (58b), then through the first four-way
valve (12), and then through the second four-way valve (13) and
thereafter flows through the suction pipe (61c) of the second
non-inverter compressor (11C). A portion of this low pressure gas
refrigerant is returned back to the second non-inverter compressor
(11C) while, on the other hand, the rest is diverged from the
suction pipe (61c) of the second non-inverter compressor (11C) to
the branch pipe (61e) and is retuned back to the first non-inverter
compressor (11B) by way of the third four-way valve (14).
Repetition of such refrigerant circulation effects cooling of the
store space.
[0127] In this operation state, the start/stop of the first and
second non-inverters (11B, 11C) and the degree of opening of the
indoor expansion valve (22) are controlled in response to the
indoor cooling load. Only one of the compressors (11B, 11C) may be
put in operation.
Refrigeration Operation Mode
[0128] The refrigeration operation mode is an operation mode that
provides only compartment cooling by the cold and freeze storage
units (30, 40). During the refrigeration operation mode, the
inverter compressor (11A) and the first non-inverter compressor
(11B) together constitute the compression mechanism (11D) of the
first system while, on the other hand, the second non-inverter
compressor (1C) alone constitutes the compression mechanism (11E)
of the second system, as shown in FIG. 3. And, the inverter
compressor (11A) and the first non-inverter compressor (11B), i.e.,
the compression mechanism (11D) of the first system, are activated
together with the booster compressor (43), and the second
non-inverter compressor (11C) is placed at rest.
[0129] In addition, as indicated by solid line representation in
FIG. 3, the first and second four-way valves (12, 13) each change
state to the first state and the third four-way valve (14) also
changes state to the first state. Furthermore, the solenoid valve
(SV2) of the cold storage unit (30) and the solenoid valve (SV3) of
the freeze storage unit (40) are placed in the opened state while,
on the other hand, the solenoid valve (SV1) of the liquid branch
pipe (66) (the second inflow pipe (63c)) which is a liquid
refrigerant inflow passageway, the outdoor expansion valve (19),
and the indoor expansion valve (22) are placed in the closed state.
In addition, in response to the operation state, the motor-operated
expansion valve (67a) of the liquid injection pipe (67) is set
either in the fully closed state or to a predetermined degree of
opening that allows liquid refrigerant to flow at a predetermined
flow rate.
[0130] In this state, discharged refrigerant from the inverter and
first non-inverter compressors (11A, 11B) flows through the first
four-way valve (12) and then through the outdoor first gas pipe
(58a) into the outdoor heat exchanger (15), and is condensed to
liquid refrigerant. The condensed liquid refrigerant flows through
the outdoor liquid pipe (62), passes through the receiver (17), and
is diverged from the integrated liquid pipe (53) of the liquid-side
interunit piping line (53, 54, 55) into the cold storage-side first
branch liquid pipe (54a) and into the freeze storage-side first
branch liquid pipe (54b).
[0131] Liquid refrigerant flowing through the cold storage-side
first branch liquid pipe (54a) flows through the cold storage
expansion valve (32) into the cold storage heat exchanger (31), is
evaporated to gas refrigerant, and then flows through the cold
storage-side branch gas pipe (51a). On the other hand, liquid
refrigerant flowing through the freeze storage-side first branch
liquid pipe (54b) flows through the freeze storage expansion valve
(42) into the freeze storage heat exchanger (41), is evaporated to
gas refrigerant. The gas refrigerant evaporated in the freeze
storage heat exchanger (41) is drawn into and compressed in the
booster compressor (43), and discharged to the freeze storage-side
branch gas pipe (51b).
[0132] The flow of the gas refrigerant evaporated in the cold
storage heat exchanger (31) and the flow of the gas refrigerant
discharged from the booster compressor (43) join together in the
first gas-side interunit piping line (51). The combined refrigerant
is then returned back through the low pressure gas pipe (64) to the
inverter compressor (11A) and the first non-inverter compressor
(11B). Repetition of such refrigerant circulation effects cooling
of the cold storage showcase compartment and cooling of the freeze
storage showcase compartment.
[0133] The pressure of refrigerant in the freeze storage heat
exchanger (41) falls below the pressure of refrigerant in the cold
storage heat exchanger (31) since the refrigerant is sucked into
the booster compressor (43). As a result, for example, the
temperature (evaporation temperature) of refrigerant in the freeze
storage heat exchanger (41) is minus 35 degrees Centigrade while,
on the other hand, the temperature (evaporation temperature) of
refrigerant in the cold storage heat exchanger (31) is minus 10
degrees Centigrade.
[0134] During the refrigeration operation mode, the start/stop of
the first non-inverter compressor (11B) and either the start/stop
or the capacity of the inverter compressor (11A) are controlled,
for example, based on LP (the pressure of low pressure refrigerant)
detected by the low pressure sensor (79), whereby the refrigeration
apparatus (1) operates in response to the refrigeration load.
[0135] For example, when effecting control of increasing the
capacity of the compression mechanism (2D), the inverter compressor
(11A) is first activated, with the first non-inverter compressor
(11B) placed at rest. If, after the capacity of the inverter
compressor (11A) increases to a maximum, there is a further
increase in the load, then the capacity of the inverter compressor
(1A) is decreased to a minimum simultaneously with activation of
the first non-inverter compressor (11B). Thereafter, if the load
increases still further, the capacity of the inverter compressor
(11A) is increased while the first non-inverter compressor (11B)
still remains activated. On the other hand, when effecting control
of reducing the compressor capacity, the opposite operation to the
compressor capacity increasing control is carried out.
[0136] The degree of opening of the cold storage and freeze storage
expansion valves (32, 42) is superheat controlled by their
temperature-sensing bulbs. This is the same as in each of the
following operation modes.
First Cooling/Refrigeration Operation Mode
[0137] The first cooling/refrigeration operation mode is an
operation mode that provides indoor space cooling by the indoor
unit (20) simultaneously with compartment cooling by the cold and
freeze storage units (30, 40). As shown in FIG. 4, during the first
cooling/refrigeration operation mode, the inverter compressor (11A)
and the first non-inverter compressor (11B) together constitute the
compression mechanism (11D) of the first system while, on the other
hand, the second non-inverter compressor (11C) alone constitutes
the compression mechanism (11E) of the second system. And, the
inverter compressor (11A), the first non-inverter compressor (11B),
and the second non-inverter compressor (11C) are all activated and,
in addition, the booster compressor (43) is also activated.
[0138] In addition, as indicated by solid line representation in
FIG. 4, the first four-way valve (12), the second four-way valve
(13), and the third four-way valve (14) each change state to the
first state. Further, the solenoid valve (SV2) of the cold storage
unit (30) and the solenoid valve (SV3) of the freeze storage unit
(40) are placed in the opened state while, on the other hand, the
solenoid valve (SV1) of the liquid branch pipe (66) (the second
inflow pipe (63c)) which is a liquid refrigerant inflow passageway
and the outdoor expansion valve (19) are placed in the closed
state. In addition, in response to the operation state, the
motor-operated expansion valve (67a) of the liquid injection pipe
(67) is set either in the fully closed state or to a predetermined
degree of opening that allows liquid refrigerant to flow to the
suction side of the compression mechanism (11D) at a predetermined
flow rate.
[0139] In this state, the flow of discharged refrigerant from the
inverter compressor (11A), the flow of discharged refrigerant from
the first non-inverter compressor (11B), and the flow of discharged
refrigerant from the second non-inverter compressor (11C) join
together in the high pressure gas pipe (57). Thereafter, the
combined refrigerant flows through the first four-way valve (12)
and then through the outdoor first gas pipe (58a) into the outdoor
heat exchanger (15), and is condensed to liquid refrigerant. The
condensed liquid refrigerant flows through the outdoor liquid pipe
(62), passes through the receiver (17), and flows through the
integrated liquid pipe (53) of the liquid-side interunit piping
line (53, 54, 55).
[0140] A portion of the liquid refrigerant flowing through the
integrated liquid pipe (53) of the liquid-side interunit piping
line (53, 54, 55) diverges therefrom into the second branch liquid
pipe (55), flows through the indoor expansion valve (22) into the
indoor heat exchanger (21), and is evaporated to gas refrigerant.
The evaporated gas refrigerant passes through the second gas-side
interunit piping line (52), then through the outdoor second gas
pipe (58b), then through the first four-way valve (12), then
through the second four-way valve (13), and then through the
suction pipe (61c), and is returned back to the second non-inverter
compressor (11C).
[0141] On the other hand, the other portion of the liquid
refrigerant flowing through the integrated liquid pipe (53) of the
liquid-side interunit piping line (53, 54, 55) diverges therefrom
into the cold storage-side first branch liquid pipe (54a) and into
the freeze storage-side first branch liquid pipe (54b). The liquid
refrigerant flowing through the cold storage-side first branch
liquid pipe (54a) flows through the cold storage expansion valve
(32) into the cold storage heat exchanger (31), is evaporated to
gas refrigerant, and flows through the cold storage-side branch gas
pipe (51a). Meanwhile, the liquid refrigerant flowing through the
freeze storage-side first branch liquid pipe (54b) flows through
the freeze storage expansion valve (42) into the freeze storage
heat exchanger (41), and is evaporated to gas refrigerant. The gas
refrigerant evaporated in the freeze storage heat exchanger (41) is
drawn into and compressed by the booster compressor (43) and then
discharged to the freeze storage-side branch gas pipe (51b).
[0142] The flow of the gas refrigerant evaporated in the cold
storage heat exchanger (31) and the flow of the gas refrigerant
discharged from the booster compressor (43) join together in the
first gas-side interunit piping line (51). Thereafter, the combined
gas refrigerant is returned back through the low pressure gas pipe
(64) to the inverter compressor (11A) and the first non-inverter
compressor (11B).
[0143] Repetition of such refrigerant circulation effects cooling
of the store space simultaneously with cooling of the cold storage
showcase compartment and cooling of the freeze storage showcase
compartment.
Second Cooling/Refrigeration Operation Mode
[0144] The second cooling/refrigeration operation mode is an
operation mode that is performed if the cooling capacity of the
indoor unit (20) is insufficient in the first cooling/refrigeration
operation mode. In the second cooling/refrigeration operation mode,
the first non-inverter compressor (11B) is switched to the air
conditioning side. As shown in FIG. 5, the setting in the second
cooling/refrigeration operation mode is basically the same as that
in the first cooling/refrigeration operation mode, with the
exception that the third four-way valve (14) changes state to the
second state.
[0145] Accordingly, during the second cooling/refrigeration
operation mode, discharged refrigerant from the inverter compressor
(11A), the first non-inverter compressor (11B), and the second
non-inverter compressor (11C) is condensed in the outdoor, heat
exchanger (15) and evaporated in the indoor heat exchanger (21),
the cold storage heat exchanger (31), and the freeze storage heat
exchanger (41), in the same way as the first cooling/refrigeration
operation mode.
[0146] Then, the refrigerant evaporated in the indoor heat
exchanger (21) is returned back to the first and second
non-inverter compressors (11B, 11C) while, on the other hand, the
refrigerant evaporated in the cold storage heat exchanger (31) and
the freeze storage heat exchanger (41) is returned back to the
inverter compressor (11A). By use of these two compressors (11B,
11C) on the air conditioning side, the lack of cooling capacity is
compensated.
Heating Operation Mode
[0147] The heating operation mode is an operation mode that
provides only indoor space heating by the indoor unit (20). During
the heating operation mode, the inverter compressor (11A) alone
constitutes the compression mechanism (11D) of the first system
while, on the other hand, the first and second non-inverter
compressors (11B, 11C) together constitute the compression
mechanism (11E) of the second system, as shown in FIG. 6. And, only
the first and second non-inverter compressors (11B, 11C), i.e., the
compression mechanism (11E) of the second system, are
activated.
[0148] Further, as indicated by solid line representation in FIG.
6, the first four-way valve (12) changes state to the second state;
the second four-way valve (13) changes state to the first state;
and the third four-way valve (14) changes state to the second
state. On the other hand, the motor-operated expansion valve (67a)
of the liquid injection pipe (67), the solenoid valve (SV2) of the
cold storage unit (30), and the solenoid valve (SV3) of the freeze
storage unit (40) are all placed in the closed state. Furthermore,
the indoor expansion valve (22) is fully opened; the solenoid valve
(SV1) of the liquid branch pipe (66) (the second inflow pipe (63c))
which is a liquid refrigerant inflow passageway is opened; and the
outdoor expansion valve (19) is controlled to a predetermined
degree of opening.
[0149] In this state, discharged refrigerant from the first
non-inverter compressor (11B) and the second non-inverter
compressor (11C) flows through the first four-way valve (12), then
through the outdoor second gas pipe (58b), and then through the
second gas-side interunit piping line (52) into the indoor heat
exchanger (21), and is condensed to liquid refrigerant. The
condensed liquid refrigerant flows through the second branch liquid
pipe (55) of the liquid-side interunit piping line (53, 54, 55) and
then through the integrated liquid pipe (53) of the liquid-side
interunit piping line (53, 54, 55), passes through the liquid
branch pipe (66) (the second inflow pipe (63c)) which is a liquid
refrigerant inflow passageway, and flows into the receiver (17).
Thereafter, the liquid refrigerant flows through the outdoor
expansion valve (19) of the auxiliary liquid pipe (65) into the
outdoor heat exchanger (15), and is evaporated to gas refrigerant.
The evaporated gas refrigerant passes through the outdoor first gas
pipe (58a), then through the first four-way valve (12), and then
through the second four-way valve (13), flows through the suction
pipe (61c) of the second non-inverter compressor (1C), and is
returned back to the first and second non-inverter compressors
(11B, 11C). Repetition of such refrigerant circulation effects
heating of the store space.
[0150] Only one of the compressors (11B, 11C) may be put in
operation, as in the cooling operation mode.
First Heating/Refrigeration Operation Mode
[0151] The first heating/refrigeration operation mode is a 100%
heat recovery operation mode that provides space heating by the
indoor unit (20) and compartment cooling by the cold and freeze
storage units (30, 40), without the use of the outdoor heat
exchanger (15). In the first heating/refrigeration operation mode,
as shown in FIG. 7, the inverter compressor (11A) and the first
non-inverter compressor (11B) together constitute the compression
mechanism (11D) of the first system while, on the other hand, the
second non-inverter compressor (11C) alone constitutes the
compression mechanism (11E) of the second system. And, the inverter
compressor (11A) and the first non-inverter compressor (11B) are
activated, and the booster compressor (43) is also activated. The
second non-inverter compressor (11C) is placed at rest.
[0152] Further, as indicated by solid line representation in FIG.
7, the first four-way valve (312) changes state to the second state
while, on the other hand, the second and third four-way valves (13,
14) each change state to the first state. Furthermore, the solenoid
valve (SV2) of the cold storage unit (30) and the solenoid valve
(SV3) of the freeze storage unit (40) are opened while, on the
other hand, the outdoor expansion valve (19) is closed. In
addition, the solenoid valve (SV1) of the liquid branch pipe (66)
(the second inflow pipe (63c)) which is a liquid refrigerant inflow
passageway is basically placed in the closed state unless: the
discharge pressure of the compression mechanism (11D) increases to
equal or exceed a predetermined value; it is estimated that the
amount of liquid refrigerant accumulated in the indoor heat
exchanger (21) and the liquid-side interunit piping line (53, 54,
55) reaches a predetermined value or above; and the temperature of
liquid refrigerant in the indoor heat exchanger (21) increases to
equal or exceed a predetermined value.
[0153] In this state, discharged refrigerant from the inverter
compressor (11A) and the first non-inverter compressor (11B) flows
through the first four-way valve (12), then through the outdoor
second gas pipe (58b), and then through the second gas-side
interunit piping line (52) into the indoor heat exchanger (21), and
is condensed to liquid refrigerant. The condensed liquid
refrigerant is diverged, before the integrated liquid pipe (53),
from the second branch liquid pipe (55) of the liquid-side
interunit piping line (53, 54, 55) into the cold storage-side first
branch liquid pipe (54a) and into the freeze storage-side first
branch liquid pipe (54b).
[0154] The liquid refrigerant flowing through the cold storage-side
first branch liquid pipe (54a) flows through the cold storage
expansion valve (32) into the cold storage heat exchanger (31), is
evaporated to gas refrigerant, and flows through the cold
storage-side branch gas pipe (51a). Meanwhile, the liquid
refrigerant flowing through the freeze storage-side first branch
liquid pipe (54b) flows through the freeze storage expansion valve
(42) into the freeze storage heat exchanger (41), and is evaporated
to gas refrigerant. The gas refrigerant evaporated in the freeze
storage heat exchanger (41) is drawn into and compressed in the
booster compressor (43) and then discharged to the freeze
storage-side branch gas pipe (51b).
[0155] The flow of the gas refrigerant evaporated in the cold
storage heat exchanger (31) and the flow of the gas refrigerant
discharged from the booster compressor (43) join together in the
first gas-side interunit piping line (51). The combined refrigerant
is then returned back through the low pressure gas pipe (64) to the
inverter compressor (11A) and the first non-inverter compressor
(11B). Repetition of such refrigerant circulation effects heating
of the store space simultaneously with cooling of the cold storage
showcase compartment and cooling of the freeze storage showcase
compartment. During the first heating/refrigeration operation mode,
the cooling capacity (the amount of heat of evaporation) of the
cold and freeze storage units (30, 40) and the heating capacity
(the amount of heat of condensation) of the indoor unit (20) are in
balance with each other whereby 100% heat recovery is
accomplished.
[0156] Also note that if the amount of liquid refrigerant flowing
to the first branch liquid pipe (54) from the second branch liquid
pipe (55) is insufficient, liquid refrigerant is drawn into the
first branch liquid pipe (54) from the receiver (17) by way of the
integrated liquid pipe (53) of the liquid-side interunit piping
line (53, 54, 55).
[0157] On the other hand, the pressure within the receiver (17)
drops when the temperature of outside air is low. Accordingly, if
the solenoid valve (SV1) of the liquid branch pipe (66) as a liquid
refrigerant inflow passageway is not placed in the closed state,
this may lead to the result that the pressure of the integrated
liquid pipe (53) of the liquid-side interunit piping line (53, 54,
55) also drops, and the liquid refrigerant condensed in the indoor
heat exchanger (21) flows neither into the cold storage heat
exchanger (31) nor into the freeze storage heat exchanger (41) but
enters the receiver (17) by way of the integrated liquid pipe (53)
from the second branch liquid pipe (55). In the present embodiment,
however, it is possible to prevent inflow of liquid refrigerant to
the receiver (17) by placing the solenoid valve (SV1) of the liquid
branch pipe (66) in the closed state. In other words, the pressure
of the integrated liquid pipe (53) can be prevented from falling to
a lower level by placing the solenoid valve (SV1) in the closed
state. This ensures that liquid refrigerant exiting the indoor heat
exchanger (21) is introduced into the cold storage heat exchanger
(31) and into the freeze storage heat exchanger (41). In addition,
it is ensured that the drop in capacity due to the insufficiency in
the flow rate of liquid refrigerant in the cold and the freeze
storage heat exchangers (31, 41) is prevented.
[0158] On the other hand, when one of the two indoor units (20) is
placed in the thermo-off state (which is a state that performs an
air supply operation in which refrigerant either stops circulating
through the indoor heat exchanger (21) or is allowed to flow
therethrough, but in very small amount) during the 100% heat
recovery operation, the indoor expansion valve (22) connected to
the indoor heat exchanger (21) is either placed in the fully closed
state or set to a very small degree of opening even when opened. At
this time, the other indoor unit (20) in operation continuously
provides space heating, and discharged refrigerant from the
compression mechanism (11D) is supplied also to the thermo-offed
indoor heat exchanger (21). However, in the thermo-offed indoor
heat exchanger (21), little refrigerant flows, resulting in gradual
accumulation of refrigerant therein.
[0159] If, at this time, there is a request that the cooling
capacity of the cold and freeze storage heat exchangers (31, 41) be
increased, an operation to increase the capacity of the compression
mechanism (11D) is carried out. As a result, the discharge pressure
of the compression mechanism (11D) increases, and if the solenoid
valve (SV1) of the liquid branch pipe (66) remains closed, the
discharge pressure increases too much. In the present invention,
however, because of the operation to place the solenoid valve (SV1)
in the opened state, it becomes possible to permit escape of the
liquid refrigerant to the receiver (17) whereby the discharge
pressure of the compressor is prevented from increasing too
much.
[0160] In addition, the following possibility exists in
conventional refrigeration apparatus in which the liquid branch
pipe (66) is provided with a relief valve. That is, the discharge
pressure of the compression mechanism (11D) increases too much
before the relief valve is opened, thereby activating the pressure
switch (78) for high pressure protection. As a result, the
compression mechanism (11D) stops operating, thereby causing the
apparatus to stop operating due to malfunction. In the present
embodiment, however, such malfunction is prevented by setting the
set pressure, at which the solenoid valve (SV1) is placed in the
opened state when the high pressure of the refrigerant circuit (50)
increase, to fall below the working pressure of the pressure switch
(78).
[0161] In addition, during the 100% heat recover operation mode,
the solenoid valve (SV1) is controlled as follows. If the amount of
liquid refrigerant accumulated in the indoor heat exchanger (21)
and the liquid-side interunit piping line (53, 54, 55) is below a
predetermined value, the solenoid valve (SV1) is closed. On the
other hand, if it is estimated that the liquid refrigerant amount
reaches the predetermined value or above, the solenoid valve (SV1)
is opened. In this case, if the value detected by the gas
temperature sensor (86) for detection of the temperature of gas
refrigerant in the indoor heat exchanger (21) approaches the
saturated temperature corresponding to the pressure, it can be
estimated that there is an accumulation of liquid refrigerant in
the indoor heat exchanger (21) and the liquid-side interunit piping
line (53, 54, 55).
[0162] If, in the way as described above, it is estimated that the
liquid refrigerant amount reaches the predetermined value or above,
then the solenoid valve (SV1) is opened to thereby permit escape of
high pressure refrigerant in the indoor heat exchanger (21) and the
liquid-side interunit piping line (53, 54, 55) into the receiver
(17). Accordingly, even in the case where there is no/little
increase in the discharge pressure of the compression mechanism
(11D), it is possible to prevent too much accumulation of liquid
refrigerant in the indoor heat exchanger (21) and the liquid-side
interunit piping line (53, 54, 55).
[0163] In addition, during the 100% heat recovery operation mode,
the solenoid valve (SV1) is controlled as follows. That is, if the
temperature of liquid refrigerant in the indoor heat exchanger (21)
is below a predetermined value, the solenoid valve (SV1) is closed.
On the other hand, if the liquid refrigerant temperature increases
to equal or exceed the predetermined value, the solenoid valve
(SV1) is opened. Also in this case, by setting the pressure
corresponding to the set temperature at which the solenoid valve
(SV1) is opened to fall below the working pressure of the pressure
switch (78) for high pressure protection, it becomes possible to
prevent the discharge pressure of the compression mechanism (11D)
from increasing too much.
[0164] Furthermore, during the 100% heat recovery operation mode,
the solenoid valve (SV1) is controlled as follows. That is, if the
pressure of liquid refrigerant in the liquid-side interunit piping
line (53, 54, 55) is below a predetermined value, the solenoid
valve (SV1) is closed. On the other hand, if the liquid refrigerant
pressure increases to equal or exceed the predetermined value, the
solenoid valve (SV1) is opened. The reason for this is that since
the heating capacity is sufficiently obtained when the pressure of
the liquid-side interunit piping line (53, 54, 55) is high, it is
necessary to permit escape of liquid refrigerant to the receiver
(17).
[0165] More specifically, the following control is possible. In the
first place, if, when it is estimated that the difference between
the temperature of gas refrigerant and the temperature of liquid
refrigerant detected respectively by the temperature sensors (86,
85) disposed respectively at the inlet and outlet sides of the
indoor heat exchanger (21)) is small during the heating operation
mode of 100% heat recovery (which is an operation mode during which
the indoor fan (23) is rotated), it is possible to estimate that:
the gas refrigerant temperature approaches the liquid refrigerant
temperature; there is an accumulation of liquid refrigerant in the
indoor heat exchanger (21); and the pressure of the liquid-side
interunit piping line (53, 54, 55) is high. Accordingly, the
solenoid valve (SV1) is controlled such that it enters the opened
state.
[0166] In the second place, since the high pressure tends to
increase when the room temperature approaches a set temperature
(i.e., when being about to be thermo-offed) or when an overload
occurs because the room temperature is high, the solenoid valve
(SV1) is controlled such that it enters the opened state. In
addition, since the room temperature is assumed to be high when the
temperature of outside air is high, the solenoid valve (SV1) is
likewise controlled such that it enters the opened state.
[0167] By virtue of the above-described arrangement, it becomes
possible to prevent the discharge pressure of the compression
mechanism (11D) from increasing too much.
Second Heating/Refrigeration Operation Mode
[0168] The second heating/refrigeration operation mode is an
operation mode that is performed when the heating capability of the
indoor unit (20) is more than needed in the first
heating/refrigeration operation mode. During the second
heating/refrigeration operation mode, as shown in FIG. 8, the
inverter compressor (11A) and the first non-inverter compressor
(11B) together constitute the compression mechanism (11D) of the
first system while on the other hand the second non-inverter
compressor (11C) alone constitutes the compression mechanism (11E)
of the second system. And the inverter compressor (11A) and the
first non-inverter compressor (11B) are activated and, in addition,
the booster compressor (43) is also activated. The second
non-inverter compressor (11C) is placed at rest.
[0169] The second heating/refrigeration operation mode is similar
to the first heating/refrigeration operation mode (for example, the
same valve setting), with the exception that the second four-way
valve (13) changes state to the second state, as indicated by solid
line representation in FIG. 8.
[0170] Accordingly, a portion of the discharged refrigerant from
the inverter compressor (11A) and the first non-inverter compressor
(11B) flows into the indoor heat exchanger (21), and is condensed
to liquid refrigerant, as in the first heating/refrigeration
operation mode. The condensed liquid refrigerant flows, before the
integrated liquid pipe (53), into the first branch liquid pipe (54)
(the cold storage-side first branch liquid pipe (54a) and the
freeze storage-side first branch liquid pipe (54b)) from the second
branch liquid pipe (55) of the liquid-side interunit piping line
(53, 54, 55).
[0171] On the other hand, the other portion of the discharged
refrigerant from the inverter compressor (11A) and the first
non-inverter compressor (11B) passes through the auxiliary gas pipe
(59), then through the second four-way valve (13), and then through
the first four-way valve (12). Thereafter, the refrigerant flows
through the outdoor first gas pipe (58a), and is condensed to
liquid refrigerant in the outdoor heat exchanger (15). The
condensed liquid refrigerant passes through the receiver (17)
during flow through the outdoor liquid pipe (62), passes through
the integrated liquid pipe (53) of the liquid-side interunit piping
line (53, 54, 55), flows to the first branch liquid pipe (54) (the
cold storage-side first branch liquid pipe (54a) and the freeze
storage-side first branch liquid pipe (54b)), and joins the
refrigerant from the second branch liquid pipe (55).
[0172] Thereafter, the liquid refrigerant flowing through the cold
storage-side first branch liquid pipe (54a) flows into the cold
storage heat exchanger (31), is evaporated to gas refrigerant, and
flows through the cold storage-side branch gas pipe (51a). On the
other hand, the liquid refrigerant flowing through the freeze
storage-side first branch liquid pipe (54b) flows into the freeze
storage heat exchanger (41), is evaporated to gas refrigerant, is
drawn into and compressed in the booster compressor (43), and is
discharged to the freeze storage-side branch gas pipe (51b). The
flow of the gas refrigerant evaporated in the cold storage heat
exchanger (31) and the flow of the gas refrigerant discharged from
the booster compressor (43) join together in the first gas-side
interunit piping line (51). The combined refrigerant is then
returned back, through the low pressure gas pipe (64), to the
inverter compressor (11A) and the first non-inverter compressor
(11B).
[0173] During the second heating/refrigeration operation mode,
repetition of such refrigerant circulation effects heating of the
store space simultaneously with cooling of the cold storage
showcase compartment and cooling of the freeze storage showcase
compartment. At this time, the cooling capacity (the amount of heat
of evaporation) of the cold and freeze storage units (30, 40) and
the heating capacity (the amount of heat of condensation) of the
indoor unit (20) are out of balance with each other, and surplus
heat of condensation is discharged to outside the room in the
outdoor heat exchanger (15).
Third Heating/Refrigeration Operation Mode
[0174] The third heating/refrigeration operation mode is an
operation mode that is performed if the heating capability of the
indoor unit (20) is insufficient in the first heating/refrigeration
operation mode. During the third heating/refrigeration operation
mode, as shown in FIG. 9, the inverter compressor (11A) and the
first non-inverter compressor (11B) together constitute the
compression mechanism (11D) of the first system while, on the other
hand, the second non-inverter compressor (11C) alone constitutes
the compression mechanism (11E) of the second system. And, the
inverter compressor (11A), the first non-inverter compressor (11B),
and the second non-inverter compressor (11C) are activated and, in
addition, the booster compressor (43) is also activated.
[0175] The third heating/refrigeration operation mode is set in the
same way as the first heating/refrigeration operation mode, with
the exception that: the degree of opening of the outdoor expansion
valve (19) is controlled; the solenoid valve (SV1) of the liquid
branch pipe (66) is opened; and the second non-inverter compressor
(11C) is activated.
[0176] Accordingly, discharged refrigerant from the inverter
compressor (11A), the first non-inverter compressor (11B), and the
second non-inverter compressor (11C) flows through the second
gas-side interunit piping line (52) into the indoor heat exchanger
(21), and is condensed to liquid refrigerant, as in the first
heating/refrigeration operation mode. The condensed liquid
refrigerant diverges from the second branch liquid pipe (55) of the
liquid-side interunit piping line (53, 54, 55) into the first
branch liquid pipe (54) (the cold storage-side first branch liquid
pipe (54a) and the freeze storage-side first branch liquid pipe
(54b)) and into the integrated liquid pipe (53).
[0177] The liquid refrigerant flowing through the cold storage-side
first branch liquid pipe (54a) flows into the cold storage heat
exchanger (31), is evaporated to gas refrigerant, and flows through
the cold storage-side branch gas pipe (51a). Meanwhile, the liquid
refrigerant flowing through the freeze storage-side first branch
liquid pipe (54b) flows into the freeze storage heat exchanger
(41), is evaporated to gas refrigerant, is drawn into and
compressed in the booster compressor (43), and is discharged to the
freeze storage-side branch gas pipe (51b). The flow of the gas
refrigerant evaporated in the cold storage heat exchanger (31) and
the flow of the gas refrigerant discharged from the booster
compressor (43) join together in the first gas-side interunit
piping line (51). The combined refrigerant is then returned back,
through the low pressure gas pipe (64), to the inverter compressor
(11A) and to the first non-inverter compressor (11B).
[0178] On the other hand, the liquid refrigerant condensed in the
indoor heat exchanger (21) and thereafter flowing through the
integrated liquid pipe (53) flows through the liquid branch pipe
(66) into the receiver (17). Thereafter, the liquid refrigerant
flows into the outdoor heat exchanger (15) by way of the outdoor
expansion valve (19) and is evaporated to gas refrigerant. The
evaporated gas refrigerant flows through the outdoor first gas pipe
(58a), then through the first four-way valve (12), and then through
the second four-way valve (13). Then, the gas refrigerant flows
through the suction pipe (61c) of the second non-inverter
compressor (11C), and is returned back to the second non-inverter
compressor (11C).
[0179] During the third heating/refrigeration operation mode,
repetition of such refrigerant circulation effects heating of the
store space simultaneously with cooling of the cold storage
showcase compartment and cooling of the freeze storage showcase
compartment. At this time, the cooling capacity (the amount of heat
of evaporation) of the cold and freeze storage units (30, 40) and
the heating capacity (the amount of heat of condensation) of the
indoor unit (20) are out of balance with each other, and the amount
of heat of evaporation lacked is obtained from the outdoor heat
exchanger (15).
Advantageous Effects of the Embodiment
[0180] In the present embodiment, during the 100% heat recovery
operation mode in which: the outdoor heat exchanger (15) is not
used; the indoor heat exchanger (21) functions as a condenser; and
the cold and freeze storage heat exchangers (31, 41) function as
evaporators, the solenoid valve (SV1) of the liquid branch pipe
(66) is placed in the closed state under normal conditions whereby
the apparatus is able to operate wherein the quantity of heat of
condensation of the indoor heat exchanger (21) and the quantity of
heat of evaporation of the cold and freeze heat exchangers (31, 41)
are in balance with each other.
[0181] On the other hand, for example, if the operation capacity of
the compression mechanism (11D) is increased when there is excess
refrigerant in the indoor heat exchanger (21) and the liquid-side
interunit piping line (53, 54, 55), the solenoid valve (SV1) is
placed in the opened state to thereby permit escape of the liquid
refrigerant accumulated in the indoor heat exchanger (21) and the
liquid-side interunit piping line (53, 54, 55) to the receiver
(17), and so it becomes possible to prevent the high pressure of
the compression mechanism (11D) from increasing too much.
Accordingly, if it is arranged such that prior to activation of the
pressure switch (78) for high pressure protection the solenoid
valve (SV1) is placed in the opened state, this makes it possible
to prevent the refrigeration apparatus from malfunctioning to stop
operating due to shutdown of the compression mechanism (11D).
[0182] In addition, in the present embodiment, the two indoor units
(20) are connected in parallel. The discharge pressure of the
compression mechanism (11D) tends to increase due to accumulation
of liquid refrigerant in the indoor heat exchanger (21) and the
liquid-side interunit piping line (53, 54, 55), when one of the two
indoor units (20) is placed in the thermo-off state, and the
apparatus tends to stop operating due to activation of the pressure
switch (78) for high pressure protection. However, the solenoid
valve (SV1) is opened prior to activation of the pressure switch
(78), thereby ensuring that the malfunction of the refrigeration
apparatus is prevented from occurring.
[0183] In addition, it is possible to prevent the occurrence of
problem conditions to the apparatus by closing the solenoid valve
(SV1) during the cooling operation mode and opening the solenoid
valve (SV1) only when the outdoor heat exchanger (15) functions as
an evaporator.
Another Embodiment
[0184] With respect to the above-described embodiment, the
following configurations may be employed.
[0185] For example, although the description has been made in
regard to an exemplary case where two indoor units (20), eight cold
storage units (30), and a freeze storage unit (40) are disposed to
a single outdoor unit (10). However, the number of utilization-side
units (20), the number of utilization-side units (30), and the
number of utilization-side units (40) may be modified according to
need as long as the 100% heat recovery operation mode is possible
to perform.
[0186] In addition, in the above-described embodiment, the
description has been made in regard to an exemplary case where the
compression mechanism (11D, 11E) is formed by the three compressors
(11A, 11B, 11C). However, the number of compressors may be modified
according to need.
[0187] It should be noted that the above-described embodiments are
essentially preferable exemplifications which are not intended in
any sense to limit the scope of the present invention, its
application, or its application range.
INDUSTRIAL APPLICABILITY
[0188] As has been described above, the present invention finds its
utility in the field of refrigeration apparatuses having multiple
systems of utilization-side heat exchangers and capable of
performing a 100% heat recovery operation mode between each
utilization-side heat exchanger.
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