EP2711654A1

EP2711654A1 - Refrigerator

Info

Publication number: EP2711654A1
Application number: EP20120785019
Authority: EP
Inventors: Hisakazu Sakai; Kouichi Nishimura
Original assignee: Panasonic Corp
Current assignee: Panasonic Corp
Priority date: 2011-05-18
Filing date: 2012-05-16
Publication date: 2014-03-26
Also published as: WO2012157263A1; CN103547872A; CN103547872B; EP2711654A4

Abstract

A refrigerator includes at least a compressor (19), an evaporator (20), and a refrigerating cycle having a condenser in a housing, the condenser includes a forced air cooled main condenser (21), a flow path switching valve (3) connected to a downstream side of the main condenser (21), and a sub-condenser connected to the downstream side of the flow path switching valve (3), and the sub-condenser has a plurality of moisture-condensation-proof pipes (1, 2) connected in parallel, and a cooling medium is caused to flow into the plurality of moisture-condensation-proof pipes (1, 2) in parallel when the refrigerating cycle is operated under a high-load condition.

Description

TECHNICAL FIELD

The present invention relates to a refrigerator having a condenser pipe (called a "moisture-condensation-proof pipe") that prevents dew condensation on a wall surface to suppress a pressure loss caused by the moisture-condensation-proof pipe.
The present invention relates to a refrigerator that has dampers for shielding cold air in a freezing room and a refrigerating room, respectively, and independently cools the freezing room and the refrigerating room by using one evaporator to improve the efficiency of a refrigerating cycle.
The present invention relates to a refrigerator and, in particular, control to suppress an inside rising temperature in a defrosting state by a heater in a refrigerator in which a storage room is cooled by latent heat and sensible heat of frost adhering to a cooler.

BACKGROUND ART

In terms of energy saving, in a household refrigerator, in addition to a condenser that performs cooling with a fan, a moisture-condensation-proof pipe that is attached to the inside of a casing outer shell to prevent dew condensation on a wall surface is used. In this case, a combustible cooling medium is used in a household refrigerator in terms of prevention of global warming, and a moisture-condensation-proof pipe having a small pipe internal diameter is used to reduce an amount of enclosed cooling medium.
Thus, a refrigerator in which the configuration of a moisture-condensation-proof pipe is changed as needed to suppress a pressure loss caused by the moisture-condensation-proof pipe is proposed (for example, see Patent Literature 1).
A conventional refrigerator will be described below with reference to the accompanying drawings.
Fig. 21 is a refrigerating cycle block diagram of a conventional refrigerator.
As shown in Fig. 21, the refrigerating cycle includes compressor 60, main condenser 61, freezing room moisture-condensation-proof pipe 62, refrigerating room moisture-condensation-proof pipe 63, and flow path switching valve 64. Furthermore, the refrigerating cycle includes refrigerating aperture diaphragm 65, refrigerating room evaporator 66, refrigerating room fan 67, freezing aperture diaphragm 68, freezing room evaporator 69, and freezing room fan 70.
In this case, in a conventional refrigerator, a refrigerating room (not shown) is cooled by using refrigerating room evaporator 66, and a freezing room (not shown) is cooled by using freezing room evaporator 69. Refrigerating room moisture-condensation-proof pipe 63 is installed on an opening of a refrigerating room (not shown) to prevent dew condensation on a wall surface, and freezing room moisture-condensation-proof pipe 62 is installed on an opening of a freezing room (not shown) to prevent dew condensation on the wall surface.
An operation of the conventional refrigerator configured as described above will be described below.
After a cooling medium discharged from compressor 60 radiates heat by main condenser 61 and freezing room moisture-condensation-proof pipe 62 and is liquefied, the cooling medium is supplied to flow path switching valve 64. When the refrigerating room (not shown) needs to be cooled, after flow path switching valve 64 is switched to radiate heat by refrigerating room moisture-condensation-proof pipe 63, decompression is performed by refrigerating aperture diaphragm 65 to supply the cooling medium to refrigerating room evaporator 66 and to evaporate the cooling medium. At this time, refrigerating room fan 67 is driven to cool the refrigerating room (not shown).
On the other hand, the freezing room (not shown) needs to be cooled, flow path switching valve 64 is switched, and decompression is performed by freezing aperture diaphragm 68 to supply the cooling medium to freezing room evaporator 69 and to evaporate the cooling medium. At this time, freezing room fan 70 is driven to cool the freezing room (not shown).
As a result, when the freezing room (not shown) is cooled, the operation can be performed without causing the cooling medium to flow into refrigerating room moisture-condensation-proof pipe 63, and a pressure loss caused by refrigerating room moisture-condensation-proof pipe 63 can be suppressed. Some heat radiated by causing the cooling medium to flow into refrigerating room moisture-condensation-proof pipe 63 can be suppressed from entering the refrigerating room (not shown) and acting as a heat load.
However, in the configuration of a conventional refrigerator, when a refrigerating room is cooled, a cooling medium must be caused to flow in series with freezing room moisture-condensation-proof pipe 62 and refrigerating room moisture-condensation-proof pipe 63, and pressure losses of the moisture-condensation-proof pipes increase a power consumption.
In the configuration of a conventional refrigerator, regardless of an installation environment or an operation state of the refrigerator, a pressure loss and a heat load caused by freezing room moisture-condensation-proof pipe 62 cannot be suppressed.
Thus, is it a problem to suppress the pressure loss or the heat load caused by the moisture-condensation-proof pipes depending on the installation environment or the operation state of the refrigerator.
The present invention is to solve the conventional problem and has as its object to adjust and suppress a pressure loss or a heat load caused by moisture-condensation-proof pipes depending on an installation environment or an operation state of a refrigerator by connecting a plurality of moisture-condensation-proof pipes in parallel to a downstream side of a main condenser through a flow path switching valve.
In a conventional household refrigerator, in terms of energy saving, a freezing room and a refrigerating room are independently cooled by using one evaporator to improve the efficiency of a refrigerating cycle. This is because the refrigerating room having a relatively high outside-air temperature is cooled at an evaporating temperature higher than that in the freezing room to improve the efficiency of the refrigerating cycle.
Furthermore, it is proposed that, by using dampers for shielding cold air arranged on the refrigerating room and the freezing room, an evaporator is defrosted by using an amount of heat of food in the refrigerating room during stoppage of the compressor (for example, see Patent Literature 2). This is to achieve energy saving by reducing the capability of a refrigerating cycle required to cool the refrigerating room while reducing electric power of a warming heater in removal of frost adhering to the evaporator.
A conventional refrigerator will be described below with reference to the accompanying drawings.
Fig. 22 is a vertical sectional view of a conventional refrigerator, Fig. 23 is a refrigerating cycle block diagram of the conventional refrigerator, Fig. 23 is a waveform chart of temperature behaviors of a temperature sensor of the conventional refrigerator and an upper part of the refrigerating room, and Fig. 24 is a flow chart showing control on a defrosting state of the conventional refrigerator.
In Fig. 22 and Fig. 23, refrigerator 11 includes casing 12, door 13, legs 14 supporting casing 12, lower machine chamber 15 arranged in a lower part of casing 12, refrigerating room 17 arranged in an upper part of casing 12, and freezing room 18 arranged in the lower part of casing 12. As components constituting the refrigerating cycle, refrigerator 11 includes compressor 56 stored in lower machine chamber 15, evaporator 20 stored on a rear side of freezing room 18, and main condenser 21 stored in lower machine chamber 15. Refrigerator 11 includes partition wall 22 partitioning lower machine chamber 15, condenser fan 23 that air-cools main condenser 21 attached to partition wall 22, evaporating dish 57 arranged on the upper part of compressor 56, and bottom plate 25 of lower machine chamber 15. Refrigerator 11 also includes plurality of intakes 26 formed in bottom plate 25, outlet 27 formed on the rear side of lower machine chamber 15, and communicating air trunk 28 that connects outlet 27 of lower machine chamber 15 and the upper part of casing 12. In this case, lower machine chamber 15 is divided into two chambers by partition wall 22 to store main condenser 21 on the windward side of condenser fan 23 and compressor 56 and evaporating dish 57 on the leeward side.
Refrigerator 11 includes, as components constituting the refrigerating cycle, moisture-condensation-proof pipe 37 located on the downstream side of main condenser 21 and thermally coupled to the outer surface of casing 12 around the opening of freezing room 18, dryer 38 located on the downstream side of moisture-condensation-proof pipe 37 to dry a circulated cooling medium, and aperture diaphragm 39 that couples dryer 38 and evaporator 20 to reduce the pressure of the circulated cooling medium. Refrigerator 11 also includes evaporator fan 50 that supplies cold air generated by evaporator 20 to refrigerating room 17 and freezing room 18, freezing room damper 51 that shields the cold air supplied to freezing room 18, refrigerating room damper 52 that shields the cold air supplied to refrigerating room 17, duct 53 that supplies the cold air to refrigerating room 17, FCC temperature sensor 54 that detects a temperature of freezing room 18, and PCC temperature sensor 55 that detects a temperature of refrigerating room 17.
An operation of the conventional refrigerator configured as described above will be described below.
When a temperature detected by PCC temperature sensor 55 increases to an ON temperature serving as a predetermined value, freezing room damper 51 is closed in a stop state of compressor 56, and refrigerating room damper 52 is opened to drive evaporator fan 50. In this manner, evaporator 20 and low-temperature sensible heat of frost adhering thereto, and latent heat of melting of the frost are used to cool refrigerating room 17 (the operation is referred to as "off cycle cooling" hereinafter).
After a predetermined period of time has elapsed after the start of the off cycle cooling, freezing room damper 51 is closed, and refrigerating room damper 52 is opened to drive compressor 56, condenser fan 23, and evaporator fan 50. By the drive of condenser fan 23, a negative pressure is set on main condenser 21 side of lower machine chamber 15 partitioned by partition wall 22 to suck outside air from plurality of intakes 26, and a positive pressure is set on compressor 56 side and evaporating dish 57 side to discharge air in lower machine chamber 15 from plurality of outlets 27 to the outside.
On the other hand, most parts of the cooling medium discharged from compressor 56 are condensed while exchanging heat with outside air in main condenser 21 and then supplied to moisture-condensation-proof pipe 37. The cooling medium passing through moisture-condensation-proof pipe 37 radiates heat to the outside through casing 12 while warming the opening of freezing room 18 and is condensed. Liquid cooling medium passing through moisture-condensation-proof pipe 37 is dehydrated by dryer 38, reduced in pressure by aperture diaphragm 39, exchanges heat with in-room air in refrigerating room 17 while being evaporated by evaporator 20, and backflows to compressor 56 as a gaseous cooling medium while cooling refrigerating room 17 (the operation is referred to as "PC cooling" hereinafter"). At this time, since the in-room air in refrigerating room 17 has a temperature higher than that of freezing room 18 and evaporator 20 is increased in temperature by the off cycle cooling, a high evaporating temperature can be rapidly achieved in the PC cooling.
When a temperature detected by PCC temperature sensor 55 decreases to an OFF temperature serving as a predetermined value, or when a temperature detected by FCC temperature sensor 54 increases to an ON temperature serving as a predetermined value, freezing room damper 51 is opened, and refrigerating room damper 52 is closed to drive compressor 56, condenser fan 23, and evaporator fan 50. When refrigerating cycle is operated like the PC cooling, heat exchange between the in-room air in freezing room 18 and evaporator 20 is performed to cool freezing room 18 (the operation is referred to "FC cooling" hereinafter).
In Fig. 24, section e corresponds to an off cycle cooling operation, section f corresponds to a PC cooling operation, section g corresponds to an FC cooling operation, and section h corresponds to a cooling stop operation. Compressor 56 is driven in section f and section g and stops in section h and section e. Freezing room 18 is cooled in section g, and refrigerating room 17 is cooled in section e and section f. In this case, a temperature change of the upper part of refrigerating room 17 is large because, since the upper part is adjacent to high-temperature outside air and the lower part is adjacent to freezing room 18 having a low temperature, a temperature difference between the upper and lower parts increases in a non-cooling period, and a flow rate of the upper part is increased in a cooling state to rapidly cool the high-temperature upper part.
When the temperature detected by FCC temperature sensor 54 decreases to the OFF temperature serving as a predetermined value, freezing room damper 51 and refrigerating room damper 52 are closed to stop compressor 56, condenser fan 23, and evaporator fan 50 (this operation is referred to as "cooling stop" hereinafter). During a normal operation, a series of operations including an off cycle cooling operation, a PC cooling operation, an FC cooling operation, and a cooling stop operation are sequentially repeated. After the normal operation is continued for a predetermined period of time, in order to remove frost adhering to evaporator 20, off cycle cooling for a relatively long period of time is performed (this operation is referred to as "off cycle defrost" hereinafter).
Fig. 25 is a flow chart in which "start of defrost" to "determination of end of defrost" shows control of off cycle defrost. As shown in Fig. 25, immediately before the PC cooling is started, when the normal operation performed for a predetermined period of time or longer, "start of defrost", i.e., the start of off cycle defrost is determined. This is because, since frost adhering to evaporator 20 is melted and removed by using an amount of heat in refrigerating room 17, a timing at which a temperature in refrigerating room 17 is relatively high and the amount of heat is large is targeted. Freezing room damper 51 is closed during stoppage of compressor 56, refrigerating room damper 52 is opened to drive evaporator fan 50. In this manner, the same series of operations as those in the off cycle cooling are performed to defrost evaporator 20.
When a DEF temperature sensor (not shown) that detects a temperature of evaporator 20 detects a temperature higher than 0°C, "determination of end of defrost" is determined, more specifically, it is determined that frost adhering to evaporator 20 can be completely removed, and the operation of off cycle defrost is ended to return to the normal operation.
By the off cycle defrost, electric power of a warming heater normally used in defrost of evaporator 20 can be reduced, and, at the same time, the capability of a refrigerating cycle required to cool refrigerating room 17 is reduced to make it possible to achieve energy saving.
The series of operations can improve the efficiency of the refrigerating cycle by keeping the temperature of evaporator 20 in PC cooling higher than that in FC cooling, and also can achieve energy saving by recycling latent heat of melting of frost adhering to evaporator 20 by off cycle cooling to reduce the capability of the refrigerating cycle required to cool refrigerating room 17 while reducing heater electric power (not shown) in a defrosting state.
However, in the configuration of a conventional refrigerator, depending on an amount of stored food in refrigerating room 17, a period of time required for off cycle defrost disadvantageously largely changes. This is because an amount of heat melting frost adhering to evaporator 20 depends on an amount of heat of the food stored in refrigerating room 17. When an amount of stored food is very few, the frost adhering to evaporator 20 is not completely melted, and there is fear that the off cycle defrost does not end.
In the configuration of the conventional refrigerator, a warming heater is added to serve as an auxiliary heat source to reliably melt the frost adhering to evaporator 20. However, an output from the warming heater to be accessorily used is difficult to be properly adjusted. This is because an amount of heat of off cycle defrost supplied to evaporator 20 is not known based on an amount of stored food in refrigerating room 17, evaporator 20 on which adhering frost is being melted does not change in temperature, and a rate of progress of defrost is difficult to be accurately determined. As a result, even though the warming heater is added to serve as an auxiliary heat source, the warming heat is used in emergency when a period of time required for off cycle defrost is abnormally long, or an excessive output is probably supplied from the beginning.
The present invention has been made to solve the conventional problems and an object thereof is to determine an amount of heat of off cycle defrost supplied to evaporator 20 in advance and properly adjust an output from the warming heater to be accessorily used to appropriately control a period of time required for off cycle defrost.
In the configuration of the conventional refrigerator, a period of time for PC cooling is reduced by the off cycle cooling. As a result, the problem that an efficient refrigerating cycle cannot be obtained in the PC cooling is posed. This is because a circulated cooling medium is in a transition state at the initial stage of activation of the refrigerating cycle and cannot sufficiently exert refrigeration capacity appropriate to an evaporating temperature.
When the off cycle cooling and the PC cooling are continuously performed to increase the temperature of evaporator 20, a time for the off cycle cooling is difficult to be appropriately controlled to secure a time for the PC cooling. This is because, since a cooling rate of the off cycle cooling largely changes depending on a frost forming state or a temperature of evaporator 20 and is different from a cooling rate of the PC cooling, by using PCC temperature sensor 55 having a time lag with reference to a change in temperature of air in refrigerating room 17, a ratio of the off cycle cooling to the PC cooling cannot be accurately controlled.
In the configuration of the conventional refrigerator, a change in temperature of refrigerating room 17, in particular, a change in temperature of the upper part disadvantageously increases. This is because, when refrigerating room 17 is independently cooled, an air temperature near an outlet port of refrigerating room 17 changes sharply more than that obtained when refrigerating room 17 and freezing room 18 are simultaneously cooled, and a non-cooling time in which refrigerating room 17 is not cooled becomes long. In order to solve the above problem, times for the off cycle cooling and the PC cooling are further shortened, and cooling and non-cooling of refrigerating room 17 must be frequently repeated. As a result, the problem that an efficient refrigerating cycle cannot be obtained in the PC cooling is posed.
The present invention has been made to solve the conventional problems and has as its object to properly secure an operation time for PC cooling and suppress a change in temperature in the refrigerating room.
An operation of the conventional refrigerator disclosed in Figs. 22 and 23 will be described below.
In Fig. 26, arrow M1 to arrow M11 represent mode switching in cooling control of a conventional refrigerator.
In a cooling stop state (the operation is referred to as an "OFF mode" hereinafter) in which all condenser fan 23, compressor 56, and evaporator fan 50 are stopped, when a temperature detected by FCC temperature sensor 54 increases to an FCC_ON temperature serving as a predetermined value, or when a temperature detected by PCC temperature sensor 55 increases to a PCC_ON temperature serving as a predetermined value (more specifically, a condition of arrow M1 is satisfied), freezing room damper 51 is closed, and refrigerating room damper 52 is opened to drive compressor 56, condenser fan 23, and evaporator fan 50 (the operation is referred to as a "PC cooling mode" hereinafter).
In a PC cooling mode, by the drive of condenser fan 23, a negative pressure is set on main condenser 21 side of lower machine chamber 15 partitioned by partition wall 22 to suck outside air from plurality of intakes 26, and a positive pressure is set on compressor 56 side and evaporating dish 57 side to discharge air in lower machine chamber 15 from plurality of outlets 27 to the outside.
On the other hand, most parts of the cooling medium discharged from compressor 56 are condensed while exchanging heat with outside air in main condenser 21 and then supplied to moisture-condensation-proof pipe 37. The cooling medium passing through moisture-condensation-proof pipe 37 radiates heat to the outside through casing 12 while warming the opening of freezing room 18 and is condensed. Liquid cooling medium passing through moisture-condensation-proof pipe 37 is dehydrated by dryer 38, reduced in pressure by aperture diaphragm 39, exchanges heat with in-room air in refrigerating room 17 while being evaporated by evaporator 20, and backflows to compressor 56 as a gaseous cooling medium while cooling refrigerating room 17.
In the PC cooling mode, when a temperature detected by FCC temperature sensor 54 decreases/increases to the FCC_OFF temperature serving as a predetermined value, and when a temperature detected by PCC temperature sensor 55 decreases the PCC_OFF temperature serving as a predetermined value (more specifically, a condition of arrow M2 is satisfied), the mode shifts to an OFF mode.
In the PC cooling mode, when the temperature detected by FCC temperature sensor 54 exhibits a temperature higher than the FCC_OFF temperature serving as a predetermined value, and when the temperature detected by PCC temperature sensor 55 decreases to the PCC_OFF temperature serving as a predetermined value (more specifically, a condition of arrow M5 is satisfied), freezing room damper 51 is opened, and refrigerating room damper 52 is closed to drive compressor 56, condenser fan 23, and evaporator fan 50. When refrigerating cycle is operated like the PC cooling, heat exchange between the in-room air in freezing room 18 and evaporator 20 is performed to cool freezing room 18 (the operation is referred to an "FC cooling mode" hereinafter).
In the FC cooling mode, when a temperature detected by FCC temperature sensor 54 decreases to the FCC_OFF temperature serving as a predetermined value, and when a temperature detected by PCC temperature sensor 55 exhibits the PCC_ON temperature or higher serving as a predetermined value (more specifically, a condition of arrow M6 is satisfied), the mode shifts to a PC cooling mode.
In the FC cooling mode, when the temperature detected by FCC temperature sensor 54 decreases to the FCC_OFF temperature serving as a predetermined value, and when a temperature detected by PCC temperature sensor 55 exhibits a temperature lower than the PCC_ON temperature serving as a predetermined value (more specifically, a condition of arrow M4 is satisfied), the mode shifts to an OFF mode.
A cooling operation using a frost adhering to evaporator 20 will be described below.
A defrosting heater (not shown) installed near evaporator 20 is energized, compressor 56 is stopped, freezing room damper 51 is closed, and refrigerating room damper 52 is opened to drive evaporator fan 50 (the operation is referred to as a "defrost mode" hereinafter). In this manner, frost adhering to evaporator 20 is melted and removed, and refrigerating room 17 is cooled by using heat of sublimation or heat of melting of the frost that is approximately removed.
The defrosting heater (not shown) installed near evaporator 20 is not energized, compressor 56 is stopped, freezing room damper 51 is closed, and refrigerating room damper 52 is opened to drive evaporator fan 50 (the operation is referred to as a "off cycle cooling mode" hereinafter). In this manner, frost adhering to evaporator 20 is melted and removed, and refrigerating room 17 is cooled by using evaporator 20 and low-temperature sensible heat and heat of sublimation or heat of melting of the frost adhering to evaporator 20. At this time, although the frost adhering to evaporator 20 is not completely melted and removed, the frost adhering to evaporator 20 is recycled to make it possible to cool refrigerating room 17 while reducing electric power of a heater (not shown) in the defrost mode.
During the FC cooling mode, when predetermined period of time Tx2 has elapsed after the power supply is turned on or the previous defrost is ended (more specifically, a condition of arrow M7 is satisfied), FC cooling is continued for a predetermined period of time to cool freezing room 18 to a temperature lower than a normal temperature (the operation is referred to as a "pre-cool mode" hereinafter). When predetermined period of time Tx3 has elapsed after the pre-cool is started (more specifically, a condition of arrow M8 is satisfied), a defrost operation is started. During the defrost, a temperature detected by a DEF temperature sensor (not shown) attached to evaporator 20 exhibits a temperature higher than a DEF_OFF temperature serving as a predetermined value, or when predetermined period of time Tx4 has elapsed after the defrost is started (more specifically, a condition of arrow M9 is satisfied), the mode shifts to an off cycle cooling mode.
In the OFF mode, when predetermined period of time Tm has elapsed after the OFF mode is started (more specifically, a condition of arrow M10 is satisfied), the mode shifts to the off cycle cooling mode.
In the off cycle cooling mode, when predetermined period of time Td has elapsed after the off cycle cooling mode is started (more specifically, a condition of arrow M11 is satisfied), the mode shifts to the OFF mode.
In this case, a cooling operation under an overloading condition will be described below.
In a conventional refrigerator, since cooling control is performed such that PC cooling that independently cools refrigerating room 17 and FC cooling that independently cools freezing room 18 are switched, when an excessive load caused by putting high-temperature foodstuff or the like in refrigerating room 17 or freezing room 18 occurs, there is fear that any one of refrigerating room 17 and freezing room 18 may not be cooled for a long period of time.
Thus, as additionally described as the condition of arrow M5, when a temperature detected by FCC temperature sensor 54 exceeds an FCC_ON temperature serving as a predetermined temperature during PC cooling, or as additionally described as the condition of arrow M6, when a temperature detected by PCC temperature sensor 55 exceeds a PCC_ON temperature serving as a predetermined value during FC cooling, until the temperature detected by PCC temperature sensor 55 reaches the PCC_OFF temperature serving as a predetermined value, or until the temperature detected by FCC temperature sensor 54 reaches the FCC_OFF temperature serving as a predetermined value, PC cooling for predetermined period of time Txr and FC cooling for predetermined period of time Txf are alternatively repeated (the operation is referred to as "alternative cooling" hereinafter). In this manner, any one of refrigerating room 17 and freezing room 18 can be avoided from being not cooled for a long period of time.
By the operation as described above, the temperature of evaporator 20 in the PC cooling mode is kept higher than that in the FC cooling mode to make it possible to improve the efficiency of a refrigerating cycle, and, by recycling latent heat of melting of frost adhering to evaporator 20 by the off cycle cooling mode, the capability of the refrigerating cycle required to cool refrigerating room 17 is reduced while reducing heater electric power (not shown) in a defrosting state to make it possible to achieve energy saving.
However, in the configuration of the conventional refrigerator, when the alternative cooling is performed under some overload condition, any one of refrigerating room 17 and freezing room 18 is disadvantageously dully cooled. This is because, in cooling times Txr and Txf set in advance under the specific overload condition, for the various overload conditions in which a power supply is turned on and a door is frequently opened or closed in summer, control is difficult to be properly performed. As a result, this is because, under some overload conditions, a load balance between refrigerating room 17 and freezing room 18 is not matched with a ratio of cooling times Txr and Txf, any one of refrigerating room 17 and freezing room 18 is insufficiently cooled. In the alternative cooling, unless cooling time Txr in the PC cooling mode in which freezing room 18 is not cooled is properly adjusted, a problem that articles of frozen food such as ice cream may be melted under some overload condition is also concerned.
The present invention has been made to solve the above problems, and has as its object to properly adjust an amount of cooling depending on a load balance between a refrigerating room and a freezing room under an overload condition while maintaining an efficient PC cooling mode as much as possible to suppress an increase in temperature.
Fig. 27 is a vertical sectional view of a conventional refrigerator, and Figs. 28 to 31 are flow charts showing control of the conventional refrigerator.
In Fig. 27, refrigerator 101 having freezing room 102 and refrigerating room 103 configures a refrigerating cycle together with compressor 104, a condenser (not shown), and a depressurizer (not shown) that are arranged inside the refrigerator and has cooler 105 that generates cold air. Refrigerator 101 has cooling fan 106 that sucks air in freezing room 102 and refrigerating room 103 to cooler 105 and resends the air to freezing room 102 and refrigerating room 103.
Refrigerator 101 has freezing room damper 107 that adjusts communication of cold air forcibly sent into freezing room 102 by cooling fan 106 to independently cool freezing room 102 and a refrigerating room damper 108 that adjusts communication of cold air forcibly sent into refrigerating room 103 by cooling fan 106 to independently cool refrigerating room 103. Furthermore, refrigerator 101 has freezing room sensor 109 that detects a temperature in freezing room 102 and refrigerating room sensor 110 that detects a temperature in refrigerating room 103.
Defrosting heater 111 to melt frost adhering to cooler 105 is arranged under cooler 105, and cooler 105 includes cooler sensor 112 that detects the temperature of cooler 105.
An operation of the refrigerator will be described below with reference to Figs. 28 to 31.
In a normal cooling state of a refrigerator, in a freezing room cooling mode, when detected temperature Tfc of freezing room sensor 109 is higher than reference temperature Tfcon in step S01, compressor 104 is started if compressor 104 does not operate in step S02 (step S03), freezing room damper 107 is opened, refrigerating room damper 108 is closed, and cooling fan 106 is operated to cool freezing room 102 (step S04).
In step S05, when detected temperature Tfc of freezing room sensor 109 is certain reference temperature Tfcoff or less, the control flow shifts to step S06 to start the refrigerating room cooling mode.
When detected temperature Tpc of refrigerating room sensor 110 is higher than certain reference temperature Tpcon in step S06, compressor 104 is started if compressor 104 does not operate in step S07 (sep S08), freezing room damper 107 is closed, refrigerating room damper 108 is opened, and cooling fan 106 is operated to cool refrigerating room 103 (step S09).
In step S10, when detected temperature Tpc of refrigerating room sensor 110 is certain reference temperature Tpcoff or less, it is determined in step S11 whether a cooling operation is continued. In step S11, when detected temperature Tfc of freezing room sensor 109 is higher than certain predetermined reference value Tfcon, the control flow returns to step S02 to start a freezing room cooling mode. When detected temperature Tfc is Tfcon or less, the control flow shifts to step S12 to start an off cycle cooling mode.
Compressor 104 is stopped in step S12. When operation time tcomp of compressor 104 is shorter than certain predetermined reference value tdefrost, the control flow shits to step S14. When detected temperature Tpc of refrigerating room sensor 110 is higher than certain predetermined reference value Tpcoff2, freezing room damper 107 is closed, refrigerating room damper 108 is opened, and cooling fan 106 is operated to perform an off cycle cooling operation to cool refrigerating room 103. When detected temperature Tpc of refrigerating room sensor 110 is certain predetermined reference value Tpcoff2 or less, freezing room damper 107 is closed, refrigerating room damper 108 is closed, cooling fan 106 is stopped to stop the off cycle cooling operation, and the control flow returns to step S1 to perform normal cooling.
When operation time tcomp of compressor 104 is certain predetermined reference value tdefrost or more in step S13, the control flow shifts to step S18 to start a defrosting mode.
In the defrosting mode, freezing room damper 107 is closed in step S18, refrigerating room damper 108 is closed, cooling fan 106 is stopped, defrosting heater 111 is energized to melt frost adhering to cooler 105. When detected temperature Tdf of cooler sensor 112 is certain predetermined reference value Tdfoff or less in step S19, a power supply to the defrosting heater is cut off to end the defrosting mode, and normal cooling is started from step S1 again.
With the above control, a refrigerator in which refrigerating room 103 can be cooled by using latent heat or sensible heat of frost adhering to cooler 105, energy consumed to melt frost in a defrosting state can be reduced, and a defrosting time is shortened to make it possible to reduce a power consumption can be proposed (for example, see Patent Literature 3).
However, in the conventional configuration, for example, even though a time for the off cycle cooling mode from the end of the full-bore defrosting mode is short, the next defrosting mode is started at the same time interval. However, in fact, when a time for the off cycle cooling mode is long, an amount of frost adhering to cooler 105 decreases.
As a result, although a time for one defrosting mode becomes short, since the number of times of defrosting mode per unit time is same because a defrosting operation is performed when an amount of adhering frost is small, a temperature in the storage room disadvantageously increases in vain.
An object of the present invention is to provide a refrigerator that includes freezing room damper 107 and predicts an amount of frost adhering to cooler 105 from operating state and controls an interval between defrosting modes so as to suppress a storage room from being increased in temperature in vain.

Citation List

Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2009-264629
PTL 2: Unexamined Japanese Patent Publication No. 9-236369
PTL 3: Japanese Patent No. 2774486

SUMMARY OF THE INVENTION

A refrigerator according to the present invention is characterized in that a plurality of moisture-condensation-proof pipes are connected in parallel to a downstream side of a main condenser through a flow path switching valve.
In this manner, in particular, in a high-load state in which an amount of circulated cooling medium is large, the plurality of moisture-condensation-proof pipes are simultaneously used in parallel to make it possible to suppress a pressure loss caused by the moisture-condensation-proof pipes. In this case, as the high-load state, a case in which a door is frequently opened or closed in summer in which an outside-air temperature or an outside-air humidity are relatively high and a case in which a high-temperature food is stored are supposed. In this case, a running rate of a refrigerating cycle increases to increase an amount of circulated cooling medium, and the periphery of the refrigerator casing on which the moisture-condensation-proof pipes are arranged needs to be prevented from dew condensation. At this time, the moisture-condensation-proof pipes are simultaneously used in parallel to reduce an amount of circulated cooling medium per pipe, so that a pressure loss caused by the moisture-condensation-proof pipes can be suppressed.
The refrigerator according to the present invention is characterized in that an amount of stored food in a refrigerating room is detected before off cycle defrost is performed, and the off cycle defrost is performed after an output from a warming heater to be accessorily used is selected. In this manner, a time required for off cycle defrost can be appropriately controlled while suppressing an output from the warming heater, a refrigerating room and a freezing room can be suppressed from being increased in temperature while the off cycle defrost is performed, and electric power of the warming heater required for defrosting is reduced to make it possible to achieve energy saving of refrigerator.
The refrigerator according to the present invention includes an FCC temperature sensor that detects the temperature of the freezing room, a PCC temperature sensor that detects the temperature of the refrigerating room, and a DFP temperature sensor that is arranged at a position higher than the PCC temperature sensor and detects the temperature of an upper part of the refrigerating room. The refrigerator according to the present invention includes an FC cooling mode that opens a freezing room damper, closes a refrigerating room damper and cools the freezing room while operating a refrigerating cycle, a PC cooling mode that closes the freezing room damper, opens the refrigerating room damper, and cools the refrigerating room while operating the refrigerating cycle, and an off cycle cooling mode that closes the freezing room damper, opens the refrigerating room damper, and operates an evaporator fan while stopping the refrigerating cycle. In this manner, the refrigerator is characterized to have the off cycle cooling mode that performs heat exchange between the evaporator and air in the refrigerating room, determines ON/OFF states of the FC cooling mode and the PC cooling mode based on a detected temperature of the FCC temperature sensor or the PCC temperature sensor, and determine an ON/OFF state of the off cycle cooling mode based on a detected temperature of the DFP temperature sensor.
In this manner, a time for the off cycle cooling is properly adjusted to make it possible to sufficiently secure a time for the PC cooling, a change in temperature of the upper part of the refrigerating room can be suppressed, and an efficient refrigerating cycle is obtained in the PC cooling state to make it possible to achieve energy saving of refrigerator.
The refrigerator according to the present invention is characterized in that, under the normal condition, cooling is performed by combining the FC cooling mode, the PC cooling mode, and the off cycle cooling mode to each other, and, under an overload condition, cooling is performed by combining a simultaneous cooling mode and the FC cooling mode to each other. In this manner, an efficient PC cooling mode is maintained as long as possible under the normal condition, and, under the high-load condition, while continuing cooling in the freezing room, amounts of cooling of the freezing room and the refrigerating room are properly adjusted to make it possible to suppress the freezing room and the refrigerating room from being increased in temperature.
The refrigerator according to the present invention includes a first storage room having an opening on a front surface thereof, a second storage room having an opening on a front surface thereof, a refrigerating cycle having a cooler that generates cold air, a cooling fan that circulates the cold air generated by the cooler to the first storage room and the second storage room, a first damper that allows the cold air flow caused by the cooling fan to flow selectively into the first storage room, a second damper that allows the cold air flow caused by the cooling fan to flow selectively into the second storage room, and a defrosting heater that melts frost adhering to the cooler with heat. The refrigerator according to the present invention includes an off cycle cooling mode that starts the cooling fan when the refrigerating cycle is stopped, opens the first damper or the second damper to cool the first storage room or the second storage room, and a defrosting mode that melts frost adhering to the cooler by the defrosting heater, and wherein the interval from the end of a defrosting mode to the next defrosting mode can be controlled.
With the configuration, in the refrigerator including the freezing room damper, a defrosting interval can be adjusted by predicting an amount of frost adhering to the cooler, and the storage rooms can be prevented from being increased in temperature in vain, so that an energy-saving refrigerator can be provided.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a vertical sectional view of a refrigerator according to a first embodiment of the present invention.
Fig. 2 is a cycle block diagram of the refrigerator according to the first embodiment of the present invention.
Fig. 3 is a block diagram of the front surface of the refrigerator according to the first embodiment of the present invention.
Fig. 4 is a block diagram of the rear surface of the refrigerator according to the first embodiment of the present invention.
Fig. 5 is a schematic diagram of a control pattern of the refrigerator according to the first embodiment of the present invention.
Fig. 6 is a vertical sectional view of a refrigerator according to a second embodiment of the present invention.
Fig. 7 is a cycle block diagram of the refrigerator according to the second embodiment of the present invention.
Fig. 8 is a waveform chart of a temperature sensor behavior of the refrigerator according to the second embodiment of the present invention.
Fig. 9 is a flow chart showing control in a defrosting state of the refrigerator according to the second embodiment of the present invention.
Fig. 10 is a vertical sectional view of a refrigerator according to a third embodiment of the present invention.
Fig. 11 is a cycle block diagram of the refrigerator according to the third embodiment of the present invention.
Fig. 12 is a waveform chart of a temperature sensor behavior of the refrigerator according to the third embodiment of the present invention.
Fig. 13 is a vertical sectional view of a refrigerator according to a fourth embodiment of the present invention.
Fig. 14 is a cycle block diagram of the refrigerator according to the fourth embodiment of the present invention.
Fig. 15 is a diagram showing state transition and switching conditions thereof in a cooling control of the refrigerator according to the fourth embodiment of the present invention.
Fig. 16 is a vertical sectional view of a refrigerator according to a fifth embodiment of the present invention.
Fig. 17 is a graph showing a relationship between an interval between defrosting modes and an integrated time of an off cycle cooling mode in the refrigerator according to the fifth embodiment of the present invention.
Fig. 18 is a graph showing a relationship between an interval between defrosting modes and an integrated door-open time in the refrigerator according to the fifth embodiment of the present invention.
Fig. 19 is a graph showing a relationship between an interval between defrosting modes and an outside-air humidity in the refrigerator according to the fifth embodiment of the present invention.
Fig. 20 is a graph showing a relationship between an interval between defrosting modes and an in-room temperature setting in the fifth embodiment of the present invention.
Fig. 21 is a cycle block diagram of a conventional refrigerator.
Fig. 22 is a vertical sectional view of the conventional refrigerator.
Fig. 23 is a cycle block diagram of the conventional refrigerator.
Fig. 24 is a waveform chart of temperature behaviors of a temperature sensor and an upper part of a refrigerating room in the conventional refrigerator.
Fig. 25 is a flow chart showing control in a defrosting state of the conventional refrigerator.
Fig. 26 is a diagram showing state transition and switching conditions thereof in a cooling control of the conventional refrigerator.
Fig. 27 is a vertical sectional view of the conventional refrigerator.
Fig. 28 is a flow chart showing control of the conventional refrigerator.
Fig. 29 is a flow chart showing control of the conventional refrigerator.
Fig. 30 is a flow chart showing control of the conventional refrigerator.
Fig. 31 is a flow chart showing control of the conventional refrigerator.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described below with reference to the accompanying drawings. However, the same reference numerals as in the conventional technique denote the same parts in the embodiments, and a description thereof will be omitted. The present invention is not limited to the following embodiments.

FIRST EMBODIMENT

Fig. 1 is a vertical sectional view of a refrigerator according to a first embodiment of the present invention, Fig. 2 is a cycle block diagram of the refrigerator according to the first embodiment of the present invention, Fig. 3 is a block diagram of the front surface of the refrigerator according to the first embodiment of the present invention, Fig. 4 is a block diagram of the rear surface of the refrigerator according to the first embodiment of the present invention, and Fig. 5 is a schematic diagram of a control pattern of the refrigerator according to the first embodiment of the present invention.
In Fig. 1, refrigerator 11 includes casing 12, door 13, legs 14 supporting casing 12, and lower machine chamber 15 arranged in a lower part of casing 12, upper machine chamber 16 arranged on an upper part on the rear surface of casing 12, refrigerating room 17 serving as a storage room arranged in an upper part of casing 12, and freezing room 18 arranged in a lower part of casing 12.
A refrigerating cycle includes compressor 19 stored in upper machine chamber 16, evaporator 20 stored on a rear surface side of freezing room 18, and main condenser 21 having a large amount of radiated heat in condensers stored in lower machine chamber 15.
The refrigerating cycle also includes partition wall 22 partitioning lower machine chamber 15, condenser fan 23 that is attached to partition wall 22 to air-cool main condenser 21, evaporating dish 24 stored on the rear surface side of lower machine chamber 15, and bottom plate 25 of lower machine chamber 15. In this case, main condenser 21 is configured by a spiral fin tube obtained by winding a strip-shaped fin on a cooling medium pipe having an internal diameter of about 4.5 mm.
Lower machine chamber 15 includes plurality of intakes 26 formed in bottom plate 25, outlet 27 formed on the rear side of lower machine chamber 15, and communicating air trunk 28 that connects outlet 27 of lower machine chamber 15 and upper machine chamber 16. In this case, lower machine chamber 15 is divided into two chambers by partition wall 22 to store main condenser 21 on the windward side of condenser fan 23 and evaporating dish 24 on the leeward side.
As shown in Fig. 2 to Fig. 4, as condensers, in addition to main condenser 21, serving as sub-condensers that radiate high-temperature heat of the refrigerating cycle, first moisture-condensation-proof pipe 1 arranged on an opening of freezing room 18 and second moisture-condensation-proof pipe 2 arranged on the rear surface side of casing 12 are installed.
Flow path switching valve 3 that connects first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 serving as the sub-condensers to the downstream side of main condenser 21, meeting point 4 that connects the downstream side of first moisture-condensation-proof pipe 1 and the downstream side of second moisture-condensation-proof pipe 2, dryer 5 arranged on the downstream side of meeting point 4, and aperture diaphragm 6 arranged on the downstream side of dryer 5 are installed. In this case, first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 are configured by cooling medium pipes each having an internal diameter of about 3.2 mm, and are thermally coupled to the outer surface of casing 12.
An operation of the refrigerator according to the first embodiment of the present invention configured as described above will be described below.
Under a high-load condition, flow path switching valve 3 is switched, a connection to first moisture-condensation-proof pipe 1 is opened, a connection to second moisture-condensation-proof pipe 2 is opened, and condenser fan 23 is driven in conjunction with the operation of compressor 19. By the drive of condenser fan 23, a negative pressure is set on main condenser 21 side of lower machine chamber 15 partitioned by partition wall 22 to suck outside air from plurality of intakes 26, and a positive pressure is set on evaporating dish 24 side to discharge air in lower machine chamber 15 from plurality of outlets 27 to the outside.
On the other hand, most parts of the cooling medium discharged from compressor 19 are condensed while exchanging heat with outside air in main condenser 21 and then supplied to first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 through flow path switching valve 3. At this time, an initial stage in which a cooling medium is condensed is set in the pipe of main condenser 21, an amount of gaseous cooling medium in main condenser 21 is larger than that in first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2, and a flow rate is relatively high in main condenser 21. For this reason, a pipe having an internal diameter larger than that of first moisture-condensation-proof pipe 1 or second moisture-condensation-proof pipe 2, desirably, a pipe having an internal diameter of 4 mm or more is preferably used.
The cooling medium passing through first moisture-condensation-proof pipe 1 radiates heat to the outside through casing 12 and is condensed while warming the opening of freezing room 18, and the cooling medium passing through second moisture-condensation-proof pipe 2 radiates heat to the outside through casing 12 and is condensed while warming the rear surface of casing 12. Liquid cooling medium passing through first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 is dehydrated by dryer 5, reduced in pressure by aperture diaphragm 6, exchanges heat with in-room air in refrigerating room 17 or freezing room 18 while being evaporated by evaporator 20, and backflows to compressor 19 as a gaseous cooling medium.
As described above, under the high-load condition, the cooling medium is caused to flow to first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 in parallel to reduce an amount of circulated cooling medium for each pipe, so that a pressure loss caused by the moisture-condensation-proof pipes can be suppressed.
Under the normal condition, flow path switching valve 3 is switched, a connection to first moisture-condensation-proof pipe 1 is closed, and a connection to second moisture-condensation-proof pipe 2 is opened. At this time, most parts of the cooling medium discharged from compressor 19 are condensed while exchanging heat with outside air in main condenser 21 and then supplied to second moisture-condensation-proof pipe 2 serving as a sub-condenser through flow path switching valve 3. The cooling medium passing through second moisture-condensation-proof pipe 2 radiates heat to the outside through casing 12 while warming the rear surface of casing 12 and is condensed.
On the other hand, first moisture-condensation-proof pipe 1 into which the cooling medium does not flow from flow path switching valve 3 does not radiate heat and has a temperature equal to a temperature therearound. At this time, a high-pressure cooling medium flows from meeting point 4 into first moisture-condensation-proof pipe 1 to almost fill first moisture-condensation-proof pipe 1 with liquid cooling medium. In this manner, the liquid cooling medium is kept accumulated and does not move in the pipe of first moisture-condensation-proof pipe 1 that is unused on the high-pressure side of the refrigerating cycle, a total amount of cooling medium circulated in the refrigerating cycle decreases. Thus, when first moisture-condensation-proof pipe 1 or second moisture-condensation-proof pipe 2 is switched to be unused, in order to suppress the decrease in the amount of cooling medium circulated in the refrigerating cycle, a pipe having an internal diameter smaller than that of main condenser 21 is used, desirably, a pipe having an internal diameter of less than 4 mm is preferably used.
Liquid cooling medium passing through second moisture-condensation-proof pipe 2 is dehydrated by dryer 5, reduced in pressure by aperture diaphragm 6, exchanges heat with in-room air in refrigerating room 17 or freezing room 18 while being evaporated by evaporator 20, and backflows to compressor 19 as a gaseous cooling medium.
As described above, under the normal load condition, first moisture-condensation-proof pipe 1 is unused, and the cooling medium is caused to flow in second moisture-condensation-proof pipe 2, so that a heat load caused by first moisture-condensation-proof pipe 1 can be reduced. In the embodiment, first moisture-condensation-proof pipe 1 is unused on the assumption that an outside-air humidity is so low that dew condensation around the opening of freezing room 18 need not be prevented. However, when dew condensation need not be prevented because the rear surface side of refrigerator 11 is in an open space, when an outside-air humidity is relatively high, second moisture-condensation-proof pipe 2 may be selected to be unused to cause the cooling medium to flow in first moisture-condensation-proof pipe 1.
Depending on dew-condensation states around casing 12, a user selectively uses first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 to make it possible to perform selection more suitable for an installation environment, and a heat load can be more efficiently reduced while avoiding the problem of occurrence of dew condensation.
Under a low-air-temperature condition, condenser fan 23 is stopped, and flow path switching valve 3 is switched, a connection to first moisture-condensation-proof pipe 1 is opened, and a connection to second moisture-condensation-proof pipe 2 is opened. At this time, the cooling medium discharged from compressor 19 passes through main condenser 21 while slightly exchanging heat with outside air and then is supplied to first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 through flow path switching valve 3.
In this case, condenser fan 23 is stopped to avoid a dull cooling state. When condenser fan 23 is driven under the low-air-temperature condition, all the cooling medium is condensed by main condenser 21, and an amount of cooling medium supplied to evaporator 20 is short to easily cause a dull cooling state in which freezing room 18 is dully cooled. In particular, in terms of suppression of a pressure loss under the high-load condition or the normal load condition, as main condenser 21, a pipe having an internal diameter larger than that of first moisture-condensation-proof pipe 1 or second moisture-condensation-proof pipe 2 serving as the sub-condenser. For this reason, when liquid cooling medium is accumulated, an amount of cooling medium is easily short.
Thus, condenser fan 23 is stopped, and the cooling medium is caused to flow into first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 in parallel, so that a condensation capacity of the refrigerating cycle is secured while suppressing a pressure loss.
The cooling medium passing through first moisture-condensation-proof pipe 1 radiates heat to the outside through casing 12 and is condensed while warming the opening of freezing room 18, and the cooling medium passing through second moisture-condensation-proof pipe 2 radiates heat to the outside through casing 12 and is condensed while warming the rear surface of casing 12. Liquid cooling medium passing through first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 is dehydrated by dryer 5, reduced in pressure by aperture diaphragm 6, exchanges heat with in-room air in refrigerating room 17 or freezing room 18 while being evaporated by evaporator 20, and backflows to compressor 19 as a gaseous cooling medium.
As described above, under the low-air-temperature condition, condenser fan 23 is stopped, the cooling medium is caused to flow into first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2, so that a pressure loss caused by the moisture-condensation-proof pipes can be suppressed while avoiding a dull cooling state caused by shortage of the amount of cooling medium.
The ranges of the high-load condition, the normal condition, and the low-air-temperature condition serving as operation conditions of the refrigerating cycle will be described below.
In Fig. 5, the abscissa indicates an outside-air temperature around a position at which refrigerator 11 is installed, the ordinate indicates an amount of circulated cooling medium in the refrigerating cycle, and a range surrounded by a frame typically shows an operation range of the refrigerating cycle. Operation ranges indicated by P, Q, and R show the high-load condition, the normal condition, and the low-air-temperature condition, respectively.
In general, since an outside-air temperature at which a dull cooling state caused by shortage of an amount of cooling medium easily occurs is 10°C or less, operation range R including a range in which at least an outside-air temperature is 10°C or less is desirably set as the range of the low-air-temperature condition. Operation range P in which an outside-air temperature higher than that in operation range R is set and an amount of circulated cooling medium is a predetermined value or more is set as a range of the high-load condition, and operation range Q in which an outside-air temperature higher than that in operation range R is set and an amount of circulated cooling medium is less than a predetermined value is set as a range of the normal condition.
When R600a is used as the cooling medium, since pressure losses of first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 become large at, in particular, an amount of circulated cooling medium of 1.5 kg/h or more, a range in which at least an amount of cooling medium is 1.5 kg/h or more is desirably included in operation range P.
In a household refrigerator including a variable-speed compressor, under a normal use condition, an amount of circulated cooling medium exceeds 1.5 kg/h when a rotating speed of the compressor is 42 r/s or more. For this reason, when operation range P is provided when the rotating speed is provided at least 42 r/s or more, the same effect as described above can be expected. Similarly, in a household refrigerator including a variable-speed compressor, under a normal use condition, an amount of circulated cooling medium is less than 1.5 kg/h when a rotating speed of the compressor is 30 r/s or more. For this reason, when operation range Q is set when the rotating speed is set at least 30 r/s or less, the same effect as described above can be expected.
Based on temperatures of an outside-air temperature, the components of the refrigerating cycle, and the like, of operation ranges P, Q, and R, a specific operation range in which an operation state of the refrigerating cycle is set is estimated. Controls under the high-load condition, the normal condition, and the low-air-temperature condition are performed, so that a pressure loss or a heat load caused by the moisture-condensation-proof pipes can be controlled.
As described above, in the refrigerator according to the embodiment, first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 are connected to the downstream side of main condenser 21 in parallel through flow path switching valve 3, so that a pressure loss and a heat load caused by first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 are adjusted and controlled depending on an installation environment and an operation state of the refrigerator.
In this manner, first moisture-condensation-proof pipe 1 and second moisture-condensation-proof pipe 2 are simultaneously used in parallel in a high-load state in which an amount of circulated cooling medium is large to make it possible to reduce the amount of circulated cooling medium and to suppress a pressure loss, and first moisture-condensation-proof pipe 1 is unused in a normal-load state in which an amount of circulated cooling medium is small to make it possible to suppress a heat load caused by first moisture-condensation-proof pipe 1.

SECOND EMBODIMENT

Fig. 6 is a vertical sectional view of a refrigerator according to a second embodiment of the present invention, Fig. 7 is a cycle block diagram of the refrigerator according to the second embodiment of the present invention, Fig. 8 is a waveform chart of a temperature sensor behavior of the refrigerator according to the second embodiment of the present invention, and Fig. 9 is a flow chart showing control in a defrosting state of the refrigerator according to the second embodiment of the present invention.
In Fig. 6 and Fig. 7, refrigerator 11 includes casing 12, door 13, legs 14 supporting casing 12, lower machine chamber 15 arranged in a lower part of casing 12, upper machine chamber 16 arranged in the upper part of casing 12, refrigerating room 17 arranged in an upper part of casing 12, and freezing room 18 arranged in the lower part of casing 12. As components constituting the refrigerating cycle, refrigerator 11 includes compressor 19 stored in upper machine chamber 16, evaporator 20 stored on a rear side of freezing room 18, and main condenser 21 stored in lower machine chamber 15.
Refrigerator 11 includes partition wall 22 partitioning lower machine chamber 15, condenser fan 23 that air-cools main condenser 21 attached to partition wall 22, evaporating dish 24 arranged on a leeward side of partition wall 22, and bottom plate 25 of lower machine chamber 15.
Refrigerator 11 also includes plurality of intakes 26 formed in bottom plate 25, outlet 27 formed on the rear side of lower machine chamber 15, and communicating air trunk 28 that connects outlet 27 of lower machine chamber 15 and upper machine chamber 16. In this case, lower machine chamber 15 is divided into two chambers by partition wall 22 to store main condenser 21 on the windward side of condenser fan 23 and evaporating dish 24 on the leeward side.
As components constituting the refrigerating cycle, refrigerator 11 includes moisture-condensation-proof pipe 41 located on the downstream side of main condenser 21 and thermally coupled to the outer surface of casing 12 around the opening of freezing room 18, dryer 42 located on the downstream side of moisture-condensation-proof pipe 41 to dry a circulated cooling medium, and aperture diaphragm 43 that couples dryer 42 and evaporator 20 to reduce the pressure of the circulated cooling medium.
The components also include evaporator fan 30 that supplies cold air generated by evaporator 20 to refrigerating room 17 and freezing room 18, freezing room damper 31 that shields cold air supplied to freezing room 18, refrigerating room damper 32 that shields cold air supplied to refrigerating room 17, duct 33 that supplies cold air to refrigerating room 17, FCC temperature sensor 34 that detects the temperature of freezing room 18, PCC temperature sensor 35 that detects the temperature of refrigerating room 17, DFP temperature sensor 36 that is located in the upper part of refrigerating room 17 and detects the temperature of refrigerating room 17 at a position higher than that of PCC temperature sensor 35, and warming heater 44 installed in a lower part of evaporator 20 and serving as an auxiliary heat source.
In this case, duct 33 is formed along a wall surface to which refrigerating room 17 and upper machine chamber 16 are adjacent, a part of cold air passing through duct 33 is discharged from a position near the center of the refrigerating room, and most of the cold air passes through the wall surface to which upper machine chamber 16 is adjacent while cooling the wall surface and then is discharged from the upper part of refrigerating room 17.
An operation of the refrigerator according to the second embodiment of the present invention configured as described above will be described below.
When a temperature detected by DFP temperature sensor 36 increases to an ON temperature serving as a predetermined value, freezing room damper 31 is closed in a stop state of compressor 19, and refrigerating room damper 32 is opened to drive evaporator fan 30.
In this manner, evaporator 20 and low-temperature sensible heat of frost adhering thereto, and latent heat of melting of the frost are used to cool refrigerating room 17 (the operation is referred to as "off cycle cooling" hereinafter). When the temperature detected by DFP temperature sensor 36 decreases to an OFF temperature serving as a predetermined value, freezing room damper 31 is closed, and refrigerating room damper 32 are closed to stop evaporator fan 30 (this operation is referred to as "cooling stop" hereinafter).
When a temperature detected by PCC temperature sensor 35 increases to an ON temperature serving as a predetermined value during off cycle cooling or stoppage of cooling, freezing room damper 31 is closed, and refrigerating room damper 32 is opened to drive compressor 19, condenser fan 23, and evaporator fan 30.
By the drive of condenser fan 23, a negative pressure is set on main condenser 21 side of lower machine chamber 15 partitioned by partition wall 22 to suck outside air from plurality of intakes 26, and a positive pressure is set on evaporating dish 24 side to discharge air in lower machine chamber 15 from plurality of outlets 27 to the outside. Air discharged from lower machine chamber 15 is sent to upper machine chamber 16 through communicating air trunk 28 to cool compressor 19.
On the other hand, most parts of the cooling medium discharged from compressor 19 are condensed while exchanging heat with outside air in main condenser 21 and then supplied to moisture-condensation-proof pipe 41. The cooling medium passing through moisture-condensation-proof pipe 41 radiates heat to the outside through casing 12 while warming the opening of freezing room 18 and is condensed.
Liquid cooling medium passing through moisture-condensation-proof pipe 41 is dehydrated by dryer 42, reduced in pressure by aperture diaphragm 43, exchanges heat with in-room air in refrigerating room 17 while being evaporated by evaporator 20, and backflows to compressor 19 as a gaseous cooling medium while cooling refrigerating room 17 (the operation is referred to as "PC cooling" hereinafter").
When a temperature detected by PCC temperature sensor 35 decreases to an OFF temperature serving as a predetermined value, or when a temperature detected by FCC temperature sensor 34 increases to an ON temperature serving as a predetermined value, freezing room damper 31 is opened, and refrigerating room damper 32 is closed to drive compressor 19, condenser fan 23, and evaporator fan 30.
When refrigerating cycle is operated like the PC cooling, heat exchange between the in-room air in freezing room 18 and evaporator 20 is performed to cool freezing room 18 (the operation is referred to "FC cooling" hereinafter). When a temperature detected by FCC temperature sensor 34 decreases to an OFF temperature serving as a predetermined value, a cooling stop operation is performed.
The off cycle cooling operates in preference to the cooling stop during stoppage of cooling, and does not operate during the PC cooling and the FC cooling. The PC cooling and the FC cooling are operated in preference to the off cycle cooling.
The OFF temperature at which the off cycle cooling is stopped is set to be higher than the ON temperature at which the PC cooling is started. As a result, in a normal operation, a series of operations including the PC cooling, the FC cooling, and the cooling stop are sequentially repeated as a basic operation. While the PC cooling operation and the FC cooling operation are not performed, the cooling stop and the off cycle cooling are repeatedly performed several times.
In Fig. 8, section a corresponds to the PC cooling operation, section b corresponds to the FC cooling operation, section c corresponds to the off cycle cooling operation, and section d corresponds to the cooling stop operation. The series of operations keep the temperature of evaporator 20 in PC cooling higher than that in FC cooling to make it possible to improve the efficiency of the refrigerating cycle, and by recycling latent heat of melting of frost adhering to evaporator 20 by off cycle cooling, the capability of the refrigerating cycle required to cool refrigerating room 17 is reduced while reducing heater electric power (not shown) in a defrosting state to make it possible to achieve energy saving.
Based on DFP temperature sensor 36 arranged in the upper part of refrigerating room 17 having a relatively large change in temperature, while the PC cooling and FC cooling operations are not performed, off cycle cooling is performed several times to make it possible to accurately adjust a ratio of the off cycle cooling that cools refrigerating room 17 to the PC cooling. For this reason, an operation time for the PC cooling can be properly secured.
With an increase in detected temperature of PCC temperature sensor 35 or FCC temperature sensor 34, even the off cycle cooling is stopped, and the operation is preferentially switched to the PC cooling or the FC cooling to make it possible to properly secure operation times for the PC cooling and the FC cooling, so that changes in temperature of refrigerating room 17 and freezing room 18 can be suppressed.
The OFF temperature at which the off cycle cooling is stopped is set to be higher than the ON temperature at which the PC cooling is started, and the off cycle cooling is controlled while keeping the temperature of DFP temperature sensor 36 arranged in the upper part of refrigerating room 17 having a relatively high temperature relatively higher than the temperature of the PCC temperature sensor to make it possible to suppress a change in temperature of the upper part of refrigerating room 17. In the embodiment, the OFF temperature at which the off cycle cooling is stopped is set to be higher than the ON temperature at which the PC cooling is started. However, even though the OFF temperature at which the off cycle cooling is stopped is set to be higher than the OFF temperature at which the PC cooling is stopped, the same effect as described above can be obtained.
Duct 33 is formed on the wall surface of refrigerating room 17 adjacent to upper machine chamber 16 having a temperature higher than that of outside air to increase the temperature of cold air cooling refrigerating room 17 in off cycle cooling and PC cooling, in particular, the temperature of cold air cooling the upper part of refrigerating room 17 so as to avoid the upper part of refrigerating room 17 from being over-cooled and to make it possible to further suppress a variation in temperature of the upper part of refrigerating room 17. Furthermore, since the upper part of refrigerating room 17 can be avoided from being over-cooled, a flow rate of cold air cooling refrigerating room 17 in PC cooling can be increased, the heat exchange efficiency of evaporator 20 is improved to make it possible to obtain higher efficiency of the refrigerating cycle in PC cooling.
After the normal operation configured by one series of operations including the PC cooling, FC cooling, off cycle cooling, and cooling stop operations is continued for a predetermined period of time, in order to remove frost adhering to evaporator 20, off cycle cooling for a relatively long period of time is performed while using warming heater 44 as required (this operation is referred to as "off cycle defrost" hereinafter). In Fig. 9, the operations from "freezing room damper is closed" to "determination of end of defrost" configure a control flow of off cycle defrost.
Immediately before the PC cooling is started, when the normal operation is performed for a predetermined period of time or longer, "start of defrost" is determined. This is because, since frost adhering to evaporator 20 is melted and removed by using an amount of heat in refrigerating room 17, a timing at which a temperature in refrigerating room 17 is relatively high and the amount of heat is large is targeted.
An amount of food stored in refrigerating room 17 is determined. Warming heater 44 is not energized when the amount of food is large, and warming heater 44 is energized when the amount of food is small. Thereafter, as one series of operations of off cycle defrost, freezing room damper 31 is closed in a state in which compressor 19 is stopped, refrigerating room damper 32 is opened to drive evaporator fan 30, thereby defrosting evaporator 20.
A method of estimating an amount of food stored in refrigerating room 17 is described here. Since the PC cooling that mainly cools refrigerating room 17 is controlled based on PCC temperature sensor 35, an average value of temperatures detected by PCC temperature sensor 35 has a good correlation with a temperature of food stored in refrigerating room 17.
On the other hand, as shown in Fig. 8, DFP temperature sensor 36 that detects a temperature of the upper part of refrigerating room 17 exhibits a temperature relatively higher than that of PCC temperature sensor 35 in the modes (b, c, and d) except for the PC cooling and tends to be close to the temperature of PCC temperature sensor 35 in the PC cooling (a). This is because cold air is mainly supplied from the upper part of refrigerating room 17 through duct 33.
As a result, when an amount of food stored in refrigerating room 17 is relatively large, and when a heat capacity in refrigerating room 17 is large, a total amount of cold air supplied from the upper part of refrigerating room 17 becomes large, the temperature detected by DFP temperature sensor 36 decreases to a temperature that is almost equal to that of PCC temperature sensor 35 or lower than that of PCC temperature sensor 35. On the other hand, when an amount of food stored in refrigerating room 17 is relatively small, and when a heat capacity in refrigerating room 17 is small, a temperature detected by DFP temperature sensor 36 decreases to up to a temperature relatively higher than that of PCC temperature sensor 35.
Thus, for example, the lowest value of the detected temperature of DFP temperature sensor 36 is lower than the detected temperature of PCC temperature sensor 35 at the same time by a predetermined value or more, it can be determined that an amount of food stored in refrigerating room 17 is large. Similarly, depending on a difference between temperature behaviors in off cycle cooling, an amount of food stored in refrigerating room 17 can also be determined. However, since a change in temperature in PC cooling is larger than that in off cycle cooling, excellent detection accuracy can be obtained.
The refrigerator in the embodiment, based on a difference between temperature behaviors of DFP temperature sensor 36 and PCC temperature sensor 35 in PC cooling, estimates an amount of food stored in refrigerating room 17. For this reason, an amount of heat held by the food stored in refrigerating room 17 can be directly estimated, an output from warming heater 44 can be accurately adjusted.
When a DEF temperature sensor (not shown) that detects a temperature of evaporator 20 detects a temperature higher than 0°C, "determination of end of defrost" is determined, more specifically, it is determined that frost adhering to evaporator 20 can be completely removed, the operation of off cycle defrost is ended to return to the normal operation after energization of warming heater 44 is stopped.
By the off cycle defrost, in particular, when an amount of food stored in refrigerating room 17 is large, warming heater 44 is not used, and, at the same time, the capability of a refrigerating cycle required to cool refrigerating room 17 is reduced to make it possible to achieve energy saving. At this time, since an amount of food stored in refrigerating room 17 is large, an amount of heat required to defrost evaporator 20 can be secured. For this reason, the off cycle deaf can be ended within an appropriate time.
In the off cycle defrost, when an amount of food stored in refrigerating room 17 is small, by using warming heater 44, both an amount of food stored in refrigerating room 17 and electric power output from warming heater 44 are used as heat sources to reduce the electric power of warming heater 44. Furthermore, the capability of a refrigerating cycle required to cool refrigerating room 17 is reduced to make it possible to achieve energy saving. At this time, the amount of heat of the food stored in refrigerating room 17 is compensated for the electric power output from warming heater 44 to make it possible to secure an amount of heat required to defrost evaporator 20. For this reason, the off cycle defrost can be ended within an appropriate time.
In the refrigerator according to the embodiment, warming heater 44 is turned on/off to adjust the heat source in off cycle defrost. However, when an output from warming heater 44 is selected such that the output is set to be high when an amount of food stored in refrigerating room 17 is large and set to be low when the amount of food is small, the same effect as described above is expected.
As described above, in the refrigerator according to the embodiment having an off cycle defrost mode in which evaporator 20 is defrosted while cooling refrigerating room 17 during stoppage of the refrigerating cycle, an amount of food stored in the refrigerating room is detected before the off cycle defrost, and, after an output from the warming heater to be accessorily used is selected, the off cycle defrost is performed to make it possible to appropriately control a time required for the off cycle defrost. The refrigerator according to the embodiment suppresses an increase in temperature of the refrigerating room or the freezing room during the off cycle defrost and reduces electric power of the warming heater required for defrost to make it possible to achieve energy saving of refrigerator.

THIRD EMBODIMENT

Fig. 10 is a vertical sectional view of a refrigerator according to a third embodiment of the present invention, Fig. 11 is a cycle block diagram of the refrigerator according to the third embodiment of the present invention, and Fig. 12 is a waveform chart of a temperature sensor behavior of the refrigerator according to the third embodiment of the present invention.
In Fig. 10 and Fig. 11, refrigerator 11 includes casing 12, door 13, legs 14 supporting casing 12, lower machine chamber 15 arranged in a lower part of casing 12, upper machine chamber 16 arranged in the upper part of casing 12, refrigerating room 17 arranged in an upper part of casing 12, and freezing room 18 arranged in the lower part of casing 12. As components constituting the refrigerating cycle, refrigerator 11 includes compressor 19 stored in upper machine chamber 16, evaporator 20 stored on a rear side of freezing room 18, and main condenser 21 stored in lower machine chamber 15. Refrigerator 11 includes partition wall 22 partitioning lower machine chamber 15, condenser fan 23 that air-cools main condenser 21 attached to partition wall 22, evaporating dish 24 arranged on a leeward side of partition wall 22, and bottom plate 25 of lower machine chamber 15.
Refrigerator 11 also includes plurality of intakes 26 formed in bottom plate 25, outlet 27 formed on the rear side of lower machine chamber 15, and communicating air trunk 28 that connects outlet 27 of lower machine chamber 15 and upper machine chamber 16. In this case, lower machine chamber 15 is divided into two chambers by partition wall 22 to store main condenser 21 on the windward side of condenser fan 23 and evaporating dish 24 on the leeward side.
As components constituting the refrigerating cycle, refrigerator 11 includes moisture-condensation-proof pipe 37 located on the downstream side of main condenser 21 and thermally coupled to the outer surface of casing 12 around the opening of freezing room 18, dryer 38 located on the downstream side of moisture-condensation-proof pipe 37 to dry a circulated cooling medium, and aperture diaphragm 39 that couples dryer 38 and evaporator 20 to reduce the pressure of the circulated cooling medium.
The components also include evaporator fan 30 that supplies cold air generated by evaporator 20 to refrigerating room 17 and freezing room 18, freezing room damper 31 that shields cold air supplied to freezing room 18, refrigerating room damper 32 that shields cold air supplied to refrigerating room 17, duct 33 that supplies cold air to refrigerating room 17, FCC temperature sensor 34 that detects the temperature of freezing room 18, PCC temperature sensor 35 that detects the temperature of refrigerating room 17, and DFP temperature sensor 36 that is located in the upper part of refrigerating room 17 and detects the temperature of refrigerating room 17 at a position higher than that of PCC temperature sensor 35.
In this case, duct 33 is formed along a wall surface to which refrigerating room 17 and upper machine chamber 16 are adjacent, a part of cold air passing through duct 33 is discharged from a position near the center of the refrigerating room, and most of the cold air passes through the wall surface to which upper machine chamber 16 is adjacent while cooling the wall surface and then is discharged from the upper part of refrigerating room 17.
An operation of the refrigerator according to the third embodiment of the present invention configured as described above will be described below.
When a temperature detected by DFP temperature sensor 36 increases to an ON temperature serving as a predetermined value, freezing room damper 31 is closed in a stop state of compressor 19, and refrigerating room damper 32 is opened to drive evaporator fan 30.
In this manner, evaporator 20 and low-temperature sensible heat of frost adhering thereto, and latent heat of melting of the frost are used to cool refrigerating room 17 (the operation is referred to as "off cycle cooling" hereinafter). When the temperature detected by DFP temperature sensor 36 decreases to an OFF temperature serving as a predetermined value, freezing room damper 31 is closed, and refrigerating room damper 32 are closed to stop evaporator fan 30 (this operation is referred to as "cooling stop" hereinafter).
When a temperature detected by PCC temperature sensor 35 increases to an ON temperature serving as a predetermined value during off cycle cooling or stoppage of cooling, freezing room damper 31 is closed, and refrigerating room damper 32 is opened to drive compressor 19 and condenser fan 23. By the drive of condenser fan 23, a negative pressure is set on main condenser 21 side of lower machine chamber 15 partitioned by partition wall 22 to suck outside air from plurality of intakes 26, and a positive pressure is set on evaporating dish 24 side to discharge air in lower machine chamber 15 from plurality of outlets 27 to the outside. Air discharged from lower machine chamber 15 is sent to upper machine chamber 16 through communicating air trunk 28 to cool compressor 19.
On the other hand, most parts of the cooling medium discharged from compressor 19 are condensed while exchanging heat with outside air in main condenser 21 and then supplied to moisture-condensation-proof pipe 37. The cooling medium passing through moisture-condensation-proof pipe 37 radiates heat to the outside through casing 12 while warming the opening of freezing room 18 and is condensed. Liquid cooling medium passing through moisture-condensation-proof pipe 37 is dehydrated by dryer 38, reduced in pressure by aperture diaphragm 39, exchanges heat with in-room air in refrigerating room 17 while being evaporated by evaporator 20, and backflows to compressor 19 as a gaseous cooling medium while cooling refrigerating room 17 (the operation is referred to as "PC cooling" hereinafter").
When a temperature detected by PCC temperature sensor 35 decreases to an OFF temperature serving as a predetermined value, or when a temperature detected by FCC temperature sensor 34 increases to an ON temperature serving as a predetermined value, freezing room damper 31 is opened, and refrigerating room damper 32 is closed to drive compressor 19, condenser fan 23, and evaporator fan 30. When refrigerating cycle is operated like the PC cooling, heat exchange between the in-room air in freezing room 18 and evaporator 20 is performed to cool freezing room 18 (the operation is referred to "FC cooling" hereinafter). When a temperature detected by FCC temperature sensor 34 decreases to an OFF temperature serving as a predetermined value, a cooling stop operation is performed.
The off cycle cooling operates in preference to the cooling stop during stoppage of cooling, and does not operate during the PC cooling and the FC cooling. The PC cooling and the FC cooling are operated in preference to the off cycle cooling. The OFF temperature at which the off cycle cooling is stopped is set to be higher than the ON temperature at which the PC cooling is started. As a result, in a normal operation, a series of operations including the PC cooling, the FC cooling, and the cooling stop are sequentially repeated as a basic operation. While the PC cooling operation and the FC cooling operation are not performed, the cooling stop and the off cycle cooling are repeatedly performed several times.
In Fig. 12, section a corresponds to the PC cooling operation, section b corresponds to the FC cooling operation, section c corresponds to the off cycle cooling operation, and section d corresponds to the cooling stop operation. The series of operations keep the temperature of evaporator 20 in PC cooling higher than that in FC cooling to make it possible to improve the efficiency of the refrigerating cycle, and by recycling latent heat of melting of frost adhering to evaporator 20 by off cycle cooling, the capability of the refrigerating cycle required to cool refrigerating room 17 is reduced while reducing heater electric power (not shown) in a defrosting state to make it possible to achieve energy saving.
Based on DFP temperature sensor 36 arranged in the upper part of refrigerating room 17 having a relatively large change in temperature, while the PC cooling and FC cooling operations are not performed, off cycle cooling is performed several times to make it possible to accurately adjust a ratio of the off cycle cooling that cools refrigerating room 17 to the PC cooling. For this reason, an operation time for the PC cooling can be properly secured.
With an increase in detected temperature of PCC temperature sensor 35 or FCC temperature sensor 34, even the off cycle cooling is stopped, and the operation is preferentially switched to the PC cooling or the FC cooling to make it possible to properly secure operation times for the PC cooling and the FC cooling, so that changes in temperature of refrigerating room 17 and freezing room 18 can be suppressed.
The OFF temperature at which the off cycle cooling is stopped is set to be higher than the ON temperature at which the PC cooling is started, and the off cycle cooling is controlled while keeping the temperature of DFP temperature sensor 36 arranged in the upper part of refrigerating room 17 having a relatively high temperature relatively higher than the temperature of the PCC temperature sensor to make it possible to suppress a change in temperature of the upper part of refrigerating room 17.
In the embodiment, the OFF temperature at which the off cycle cooling is stopped is set to be higher than the ON temperature at which the PC cooling is started. However, even though the OFF temperature at which the off cycle cooling is stopped is set to be higher than the OFF temperature at which the PC cooling is stopped, the same effect as described above can be obtained.
Duct 33 is formed on the wall surface of refrigerating room 17 adjacent to upper machine chamber 16 having a temperature higher than that of outside air to increase the temperature of cold air cooling refrigerating room 17 in off cycle cooling and PC cooling, in particular, a temperature of the cold air cooling the upper part of refrigerating room 17, so that the upper part of refrigerating room 17 is avoided from being overcooled to make it possible to further suppress a variation in temperature of the upper part of refrigerating room 17. Furthermore, since the upper part of refrigerating room 17 can be avoided from being overcooled, a flow rate of cold air cooling refrigerating room 17 in the PC cooling state can be increased, and the heat exchange efficiency of evaporator 20 is improved to make it possible to obtain higher refrigerating cycle efficiency in the PC cooling state.
As described above, in the refrigerator according to the embodiment having, in addition to an FC cooling mode (b) and a PC cooling mode (a), an off cycle cooling mode (c) that cools refrigerating room 17 during stoppage of a refrigerating cycle, independently of control of the FC cooling mode (b) and the PC cooling mode (a), the off cycle cooling mode (c) is controlled based on a detected temperature of DFP temperature sensor 36 installed at a position higher than that of PCC temperature sensor 35 that controls the PC cooling and having a change in temperature larger than that of PCC temperature sensor 35 to properly adjust a time for the off cycle cooling. As a result, a time for the PC cooling can be sufficiently secured, and a change in temperature of refrigerating room 17 can be suppressed.

FOURTH EMBODIMENT

Fig. 13 is a vertical sectional view of a refrigerator according to a fourth embodiment of the present invention, Fig. 14 is a cycle block diagram of the refrigerator according to the fourth embodiment of the present invention, and Fig. 15 is a diagram showing state transition and switching conditions thereof in a cooling control of the refrigerator according to the fourth embodiment of the present invention.
In Fig. 13 and Fig. 14, refrigerator 11 includes casing 12, door 13, legs 14 supporting casing 12, lower machine chamber 15 arranged in a lower part of casing 12, upper machine chamber 16 arranged in the upper part of casing 12, refrigerating room 17 arranged in an upper part of casing 12, and freezing room 18 arranged in the lower part of casing 12.
As components constituting the refrigerating cycle, refrigerator 11 includes compressor 19 stored in upper machine chamber 16, evaporator 20 stored on a rear side of freezing room 18, and main condenser 21 stored in lower machine chamber 15. Refrigerator 11 includes partition wall 22 partitioning lower machine chamber 15, condenser fan 23 that air-cools main condenser 21 attached to partition wall 22, evaporating dish 24 arranged on a leeward side of partition wall 22, and bottom plate 25 of lower machine chamber 15.
In this case, compressor 19 is a variable-speed compressor and uses 6-step rotating speeds selected from 20 to 80 r/s. This is because freezing capability is adjusted by switching the rotating speed of compressor 19 in the six steps of low to high speeds while avoiding the pipes or the like from being resonant. Compressor 19 operates at a low speed at the start, and the speed of compressor 19 increases when an operation time for cooling refrigerating room 17 or freezing room 18 becomes long.
This is because the low speed that is most efficient is mainly used, and a proper relative high rotating speed is used for an increase in load of refrigerating room 17 or freezing room 18 caused by a high outside-air temperature or opening/closing the door.
At this time, although the rotating speed of compressor 19 is controlled independently of a cooling operation mode of refrigerator 11, a rotating speed at the start of the PC cooling mode having a high evaporating temperature and relatively high freezing capability may be set to be lower than that in the FC cooling mode. With a decrease in temperature of refrigerating room 17 or freezing room 18, the freezing capability may be adjusted while reducing the speed of compressor 19.
Refrigerator 11 also includes plurality of intakes 26 formed in bottom plate 25, outlet 27 formed on the rear side of lower machine chamber 15, and communicating air trunk 28 that connects outlet 27 of lower machine chamber 15 and upper machine chamber 16. In this case, lower machine chamber 15 is divided into two chambers by partition wall 22 to store main condenser 21 on the windward side of condenser fan 23 and evaporating dish 24 on the leeward side.
As components constituting the refrigerating cycle, refrigerator 11 includes moisture-condensation-proof pipe 37 located on the downstream side of main condenser 21 and thermally coupled to the outer surface of casing 12 around the opening of freezing room 18, dryer 38 located on the downstream side of moisture-condensation-proof pipe 37 to dry a circulated cooling medium, and aperture diaphragm 39 that couples dryer 38 and evaporator 20 to reduce the pressure of the circulated cooling medium.
The components also include evaporator fan 30 that supplies cold air generated by evaporator 20 to refrigerating room 17 and freezing room 18, freezing room damper 31 that shields cold air supplied to freezing room 18, refrigerating room damper 32 that shields cold air supplied to refrigerating room 17, duct 33 that supplies cold air to refrigerating room 17, FCC temperature sensor 34 that detects the temperature of freezing room 18, PCC temperature sensor 35 that detects the temperature of refrigerating room 17, and DFP temperature sensor 36 that is located in the upper part of refrigerating room 17 and detects the temperature of refrigerating room 17 at a position higher than that of PCC temperature sensor 35.
In this case, duct 33 is formed along a wall surface to which refrigerating room 17 and upper machine chamber 16 are adjacent, a part of cold air passing through duct 33 is discharged from a position near the center of the refrigerating room, and most of the cold air passes through the wall surface to which upper machine chamber 16 is adjacent while cooling the wall surface and then is discharged from the upper part of refrigerating room 17.
An operation of the refrigerator according to the fourth embodiment of the present invention configured as described above will be described below.
In Fig. 15, arrows L1 to L15 indicate mode switchings in cooling control of the refrigerator according to the fourth embodiment of the present invention. A detailed description of the same cooling operation mode and the same mode switching condition as those in the conventional refrigerator shown in Fig. 26 is omitted.
An off cycle cooling mode will be described below.
In the OFF mode, when a condition of arrow L1 (more specifically, a condition of arrow M1) is satisfied, or when a temperature detected by DFP temperature sensor 36 increases a DFP_ON temperature serving as a predetermined value (more specifically, a condition of arrow L10 is satisfied), the mode shifts to the off cycle cooling mode.
In the off cycle cooling mode, a temperature detected by FCC temperature sensor 34 does not exceed the FCC_ON temperature serving as a predetermined value, a temperature detected by PCC temperature sensor 35 does not exceed a PCC_ON temperature serving as a predetermined value, and a temperature detected by DFP temperature sensor 36 decreases to a DFP_OFF temperature serving as a predetermined value (more specifically, a condition of arrow L11 is satisfied). In this case, the mode shifts to the OFF mode. In the off cycle cooling mode, when the condition of arrow L1 (more specifically, a condition of arrow M1) is satisfied, the mode shifts to the PC cooling mode.
In this manner, by using DFP temperature sensor 36 arranged in an upper part of refrigerating room 17, a time for the off cycle cooling mode can be properly adjusted. In a conventional refrigerator, since off cycle cooling for predetermined time td is always performed, the temperature of refrigerating room 17 may excessively decrease.
A cooling operation under an overloading condition will be described below.
In the PC cooling mode, when a temperature detected by FCC temperature sensor 34 exhibits a temperature higher than the FCC_OFF temperature serving as a predetermined value, and when a temperature detected by PCC temperature sensor 35 decreases the PCC_OFF temperature serving as a predetermined value (more specifically, a condition of arrow L5 is satisfied), the mode shifts to the FC cooling mode. In addition, as additionally described in the condition of arrow L5, in the PC cooling mode, after predetermined time Tx1 has elapsed, when a difference between the temperature detected by FCC temperature sensor 34 and the FCC_OFF temperature serving as a predetermined value is equal to or larger than a difference between the temperature detected by PCC temperature sensor 35 and the PCC_OFF temperature serving as a predetermined value, the mode shifts to the FC cooling mode.
In the FC cooling mode, when a temperature detected by FCC temperature sensor 34 decreases to the FCC_OFF temperature serving as a predetermined value, and when a temperature detected by PCC temperature sensor 35 exhibits the PCC_ON temperature or higher serving as a predetermined value (more specifically, a condition of arrow L6 is satisfied), the mode shifts to a PC cooling mode. In addition, as additionally described in the condition of arrow L6, in the FC cooling mode, after predetermined time Tx1 has elapsed, when a difference between the temperature detected by FCC temperature sensor 34 and the FCC_OFF temperature serving as a predetermined value is equal to or smaller than a difference between the temperature detected by PCC temperature sensor 35 and the PCC_OFF temperature serving as a predetermined value, the mode shifts to the PC cooling mode.
In this manner, under an overload condition such as in a power-on state in which refrigerating room 17 and freezing room 18 have high temperatures, the PC cooling mode and the FC cooling mode are alternatively switched every predetermined time Tx1, and one of the modes the temperature of which is larger different from the OFF temperature serving as a measure to end cooling can be preferentially cooled. As a result, cooling operation times can be more flexibly distributed in comparison with alternative cooling that is performed with fixed cooling times in a conventional refrigerator.
However, even though alternative cooling with flexible cooling operation times is performed, since freezing room 18 is intermittently cooled, the temperature thereof may probably exceed the upper limit of a storage temperature of frozen food such as ice cream. Thus, only under the overload condition, an operation of simultaneously cooling refrigerating room 17 and freezing room 18 (the operation will be referred to as "simultaneous cooling mode" hereinafter) is added.
The simultaneous cooling mode opens freezing room damper 31 and opens refrigerating room damper 32 to drive compressor 19, condenser fan 23, and evaporator fan 30. In the simultaneous cooling mode, by the drive of condenser fan 23, a negative pressure is set on main condenser 21 side of lower machine chamber 15 partitioned by partition wall 22 to suck outside air from plurality of intakes 26, and a positive pressure is set on compressor 19 side and evaporating dish 57 side to discharge air in lower machine chamber 15 from plurality of outlets 27 to the outside.
On the other hand, most parts of the cooling medium discharged from compressor 19 are condensed while exchanging heat with outside air in main condenser 21 and then supplied to moisture-condensation-proof pipe 37. The cooling medium passing through moisture-condensation-proof pipe 37 radiates heat to the outside through casing 12 while warming the opening of freezing room 18 and is condensed. Liquid cooling medium passing through moisture-condensation-proof pipe 37 is dehydrated by dryer 38, reduced in pressure by aperture diaphragm 39, exchanges heat with in-room air in refrigerating room 17 and freezing room 18 while being evaporated by evaporator 20, and backflows to compressor 19 as a gaseous cooling medium while cooling refrigerating room 17 and freezing room 18.
At this time, evaporator fan 30 is rotated at a high speed to secure a flow rate required to cool refrigerating room 17 and freezing room 18 in parallel. As a result, since air having a temperature and a wind speed higher than those in the FC cooling mode to cause a temperature of air blown out of evaporator 20 to tend to increase, compressor 19 is desirably operated at a relatively high rotating speed to secure appropriate freezing capability. When compressor 19 is operated at a low speed in the simultaneous cooling mode, there is fear that the temperature of air blown out of evaporator 20 increases to make it impossible to cool freezing room 18 to a low temperature.
Thus, in the PC cooling mode, when the rotating speed of compressor 19 is a predetermined rotating speed or more (more specifically, a condition of arrow L12 is satisfied), the mode shifts to the simultaneous cooling mode. In the simultaneous cooling mode, when the rotating speed of compressor 19 is lower than a predetermined rotating speed (more specifically, a condition of arrow L13 is satisfied), the mode shifts to the PC cooling mode.
Mode switching between arrow L12 and arrow L13 is performed in preference to other state transitions. This is because the overload condition is detected by refrigerator 11 when the rotating speed of compressor 19 increases to a predetermined rotating speed or more to cause the mode to shift to the simultaneous cooling mode, and, when the rotating speed of compressor 19 is lower than the predetermined rotating speed, the temperature of air blown out of evaporator 20 is prevented from increasing to avoid freezing room 18 from being impossible to be cooled to a low temperature.
In the simultaneous cooling mode, when a temperature detected by PCC temperature sensor 35 decreases to the PCC_OFF temperature or lower serving as a predetermined value, and when a temperature detected by FCC temperature sensor 34 exhibits the FCC_LIM temperature or higher serving as a predetermined value higher than the FCC_ON temperature (more specifically, a condition of arrow L14 is satisfied) after the predetermined time Tx5 elapsed, the mode shifts to an FC cooling mode. This is because, in order to suppress an increase in temperature of refrigerating room 17 that is not cooled in the FC cooling mode, the simultaneous cooling mode is continued until the temperature of freezing room 18 increases to the upper limit of an allowable temperature.
Thus, the FCC_LIM temperature that is detected by FCC temperature sensor 34 is desirably set to be a predetermined value that is higher than the FCC_ON temperature serving as the upper-limit temperature in the normal cooling by 2°C to 5°C and corresponds to weak cooling.
In the embodiment, the condition of arrow L12 to cause the mode to shift to the simultaneous cooling mode corresponding to the overload condition is regulated by the rotating speed of compressor 19. However, a power-on state at a high outside-air temperature, frequent door opening/closing, or the like may be detected to cause the mode to shift to the simultaneous cooling mode.
Even though compressor 19 does not increase in speed, when refrigerator 11 is definitely set in an overload condition, the mode can be more quickly caused to shift to the simultaneous cooling mode.
In this case, the condition of arrow L13 may be changed such that the simultaneous cooling mode is canceled by detecting that refrigerating room 17 or freezing room 18 decreases in temperature to some extent. In this manner, as in the embodiment, the most efficient PC cooling mode can be used for a long time.
Defrost performed when evaporator 20 is frosted in the simultaneous cooling mode will be described below.
In the simultaneous cooling mode, when a temperature detected by FCC temperature sensor 34 exhibits a temperature lower than the FCC_LIM temperature serving as a predetermined value, and when a temperature detected by PCC temperature sensor 35 exhibits a temperature higher than the PCC_OFF temperature serving as a predetermined value, and, after predetermined time Tx6 has elapsed from the start of the simultaneous cooling mode, a difference between the temperature detected by PCC temperature sensor 35 and a temperature detected by DFP temperature sensor 36 is a predetermined value αor less (more specifically, a condition of arrow L15 is satisfied), the mode shifts to a defrost mode.
In this mode, when evaporator 20 is frosted in the simultaneous cooling mode to cause refrigerating room 17 to be tend to be dully cooled, normal defrost performed every predetermined time Tx2 is performed ahead of time. A defrosting interval of evaporator 20 is shortened to make it possible to early recover the cooling capacity of refrigerating room 17.
In the simultaneous cooling mode, evaporator fan 30 is rotated at a high speed to secure flow rates of airs that are sent to both refrigerating room 17 and freezing room 18 in parallel. However, when evaporator 20 is strongly frosted, sufficient flow rates cannot be secured. At this time, a flow rate in refrigerating room 17 having a relatively long path for air sent from evaporator 20 is considerably lower than that in freezing room 18 formed right in front of evaporator 20, a temperature difference between DFP temperature sensor 36 relatively close to a blow-out position of cold air located in the upper part of refrigerating room 17 and PCC temperature sensor 35 located near the center of refrigerating room 17 becomes smaller than predetermined value α.
Thus, by using a difference between the temperature detected by PCC temperature sensor 35 and the temperature detected by DFP temperature sensor 36, it can be detected whether a cooling state of refrigerating room 17 in the simultaneous cooling mode is normal or whether refrigerating room 17 tends to be dully cooled due to frost adhering to evaporator 20. When refrigerating room 17 tends to be dully cooled, the defrosting interval of evaporator 20 is shortened to make it possible to early recover the cooling capacity.
As described above, in the refrigerator according to the embodiment having, in addition to an FC cooling mode and a PC cooling mode, an off cycle cooling mode that cools a refrigerating room during stoppage of a refrigerating cycle, while a simultaneous cooling mode is realized only under an overload condition to maintain an efficient PC cooling mode as long as possible, amounts of cooling of the refrigerating room and the freezing room under the overload condition are automatically appropriately adjusted to make it possible to suppress the temperatures of refrigerating room and the freezing room from increasing.

FIFTH EMBODIMENT

Fig. 16 is a vertical sectional view of a refrigerator according to a fifth embodiment of the present invention. Fig. 17 is a graph showing a relationship between an interval between defrosting modes and an integrated time of an off cycle cooling mode in the refrigerator according to the fifth embodiment of the present invention. Fig. 18 is a graph showing a relationship between an interval between defrosting modes and an integrated door-open time in the refrigerator according to the fifth embodiment of the present invention. Fig. 19 is a graph showing a relationship between an interval between defrosting modes and an outside-air humidity in the refrigerator according to the fifth embodiment of the present invention. Fig. 20 is a graph showing a relationship between an interval between defrosting modes and an in-room temperature setting in the fifth embodiment of the present invention.
As shown in Fig. 16, the refrigerator according to the embodiment includes freezing room door 113 that can airtightly closes an opening of freezing room 102 and refrigerating room door 114 that can airtightly closes an opening of refrigerating room 103.
At openings 102a and 103a of freezing room 102 and refrigerating room 103, freezing room door sensor 115 and refrigerating room door sensor 116 that detect open/close of freezing room door 113 and refrigerating room door 114 and are configured by, for example, hall ICs and magnets are arranged.
Furthermore, humidity sensor 117 that detects an outside-air humidity is arranged on an outer wall side of refrigerator 101. In refrigerator 101, controller 118 that controls an operation of the refrigerating cycle and controls the operation of the refrigerating cycle based on a control state of the refrigerating cycle and outputs from freezing room door sensor 115, refrigerating room door sensor 116, and humidity sensor 117 is arranged.
An operation of the refrigerator configured as described above will be described below with reference to Figs. 17 to 20.
In a normal cooling state, when compressor 104 is stopped in step S12 shown in Fig. 30, when operation time tcomp of compressor 104 is tdefrost or more in step S13, the control flow shifts to step S18 shown in Fig. 31 to start a defrosting mode.
Time tdefrost has predetermined initial value tdefrostb, and varies depending on an off cycle cooling time, a door opening/closing time, an outside-air humidity, and an in-room temperature setting.
A relationship between the off cycle cooling time and time tdefrost will be described below with reference to Fig. 17. In the off cycle cooling, freezing room damper 107 is closed, refrigerating room damper 108 is opened, and cooling fan 106 is operated to cool refrigerating room 103 by using latent heat or sensible heat of frost adhering to cooler 105 and to draw heat from the frost adhering to cooler 105. For this reason, an amount of heat required to melt the frost adhering to cooler 105 decreases when the off cycle cooling time is long.
On the other hand, an integrated time of the off cycle cooling is counted by controller 118, and controller 118 performs control such that time tdefrost becomes long when the integrated time is long. In this manner, time tdefrost can be changed in accordance with a degree of frosting to cooler 105 depending on the integrated time of the off cycle cooling, the number of times of an operation in a defrosting mode can be optimized, and an increase in temperature in the rooms can be appropriately prevented.
A relationship between a door open/close time and time tdefrost will be described below with reference to Fig. 18. During the operation of the refrigerator, in order to pick up food or the like in a storage room, freezing room door 113 or refrigerating room door 114 is opened/closed. At this time, outside air having a temperature and a humidity that are higher than those of air in the storage room humidified and circulated by cooler 105 flows in the storage room. The high-temperature and high-humidity air flowing in the refrigerator passes through cooler 105 by the operation of cooling fan 106 to form frost on cooler 105. Thus, when the door open/close time is long, an amount of frost adhering to cooler 105 increases. In contrast to this, when the door open/close time is short, the amount of frost decreases.
On the other hand, an integrated door open/close time is counted by freezing room door sensor 115 and refrigerating room door sensor 116 and output to controller 118. Controller 118 performs control such that time tdefrost becomes short when the integrated door open/close time is long. In this manner, time tdefrost can be changed in accordance with a degree of frosting to cooler 105 depending on the integrated door open/close time, the number of times of an operation in a defrosting mode can be optimized, and an increase in temperature in the rooms can be appropriately prevented.
A relationship between an outside-air humidity and time tdefrost will be described below with reference to Fig. 19. Freezing room 102 and refrigerating room 103 are airtightly closed by freezing room door 113 and refrigerating room door 114 but not completely airtightly closed, and have small clearances. Through the small clearances, the rooms communicate with the outside to cause outside-air humidity to flow into the rooms.
As described above, when the door is opened/closed, outside-air humidity flows in the rooms. For this reason, when an outside-air humidity is high, an amount of humidity flowing in the rooms increases, and an amount of frost adhering to cooler 105 increases. When the outside-air humidity is low, the amount of frost decreases. On the other hand, the outside-air humidity is measured by humidity sensor 117, an average humidity from a full-bore defrosting mode is calculated and output to controller 118. Controller 118 controls such that time tdefrost is short when the outside-air humidity is high. In this manner, time tdefrost can be changed in accordance with a degree of frosting to cooler 105 depending on the outside-air humidity, the number of times of an operation in a defrosting mode can be optimized, and an increase in temperature in the rooms can be appropriately prevented.
A relationship between an in-room temperature setting and time tdefrost will be described below with reference to Fig. 20. When the temperature settings of freezing room 102 and refrigerating room 103 decreases, in-room air temperatures decrease. Accordingly, the temperature of cooler 105 also decreases. When the temperature of cooler 105 decreases, an amount of dehumidification from passing in-room air also increases, and an amount of frost adhering to cooler 105 also increases. In contrast to this, since the temperature of cooler 105 increases when the temperature setting becomes high, an amount of dehumidification also decreases, and an amount of frost adhering to cooler 105 decreases.
On the other hand, the in-room temperature setting is detected by controller 118, and controller 118 controls such that time tdefrost becomes long when the in-room temperature setting is high. In this manner, time tdefrost can be changed in accordance with a degree of frosting to cooler 105 depending on the in-room temperature setting, the number of times of an operation in a defrosting mode can be optimized, and an increase in temperature in the rooms can be appropriately prevented.
As described above, in the refrigerator according to the embodiment, since an increase in temperature in the rooms can be prevented, a refrigerator having a large cooling capacity can be obtained.
In the embodiment, time tdefrost is described with reference to a control method that controls time tdefrost in relation to an increase/decrease of control factors. However, even though time tdefrost is controlled in phase such that increasing/decreasing widths of time tdefrost are determined in units of ranges of the control factors, the same effect as described above can be obtained, and the control can be advantageously easily performed.
In the embodiment, the off cycle cooling is controlled to be ended by a detected temperature of refrigerating room sensor 110. However, for example, the same effect as described above can also be obtained by a method that performs control by determining, for example, an off cycle cooling time or a method that performs control by another control factor.
In the embodiment, as a refrigerator, a refrigerator having two rooms, i.e., freezing room 102 and refrigerating room 103 is described. However, when a refrigerator having three rooms including, for example, a vegetable room is controlled regardless of the number of storage rooms, the same effect as described above can be obtained.
In the embodiment, control that detects an outside-air humidity is described. However, an outside-air humidity and an outside-air temperature are measured, and time tdefrost is controlled to be changed with reference to the outside-air temperature, so that optimum control can be performed.
The refrigerator according to the embodiment is described with reference to specifications in which cold air is generated by a cooling medium compression type refrigerating cycle using compressor 104. However, even though any freezing system that generates cold air by cooler 105 is used, the same effect as described above can be obtained.
As described above, the present invention is a refrigerator that includes a forced air draft main condenser, and a flow path switching valve connected to the downstream side of the main condenser and a plurality of moisture-condensation-proof pipes that are connected to the downstream side of the flow path switching valve in parallel, a cooling medium being caused to flow into the plurality of moisture-condensation-proof pipes in parallel in a high-load state.
In this manner, in particular, in a high-load state in which an amount of circulated cooling medium is large, the plurality of moisture-condensation-proof pipes are simultaneously used in parallel to make it possible to suppress a pressure loss caused by the moisture-condensation-proof pipes. In this case, as the high-load state, a case in which a door is frequently opened or closed in summer in which an outside-air temperature or an outside-air humidity are relatively high and a case in which a high-temperature food is stored is supposed. In this case, a running rate of a refrigerating cycle increases to increase an amount of circulated cooling medium, and the periphery of the refrigerator casing on which the moisture-condensation-proof pipes are arranged need to be prevented from dew condensation. At this time, the moisture-condensation-proof pipes are simultaneously used in parallel to reduce an amount of circulated cooling medium per pipe, so that a pressure loss caused by the moisture-condensation-proof pipes can be suppressed.
The present invention is a refrigerator characterized in that, when a refrigerating cycle is operated under a normal condition, the number of moisture-condensation-proof pipes to be used is smaller than that in a high-load state.
In this manner, the number of moisture-condensation-proof pipes used in the normal load state in which an amount of circulated cooling medium is small is reduced to make it possible to suppress a heat load caused by the moisture-condensation-proof pipes. In this case, the normal load state is determined on the assumption that a door is opened/closed for a long time in autumn to spring in which a temperature and a humidity are relatively low. In this case, a running rate of a refrigerating cycle decreases to reduce an amount of circulated cooling medium, and dew condensation on the periphery of the refrigerator casing on which moisture-condensation-proof pipes are arranged rarely need to be prevented.
At this time, some of the moisture-condensation-proof pipes is selectively used to make it possible to suppress a heat load caused by the moisture-condensation-proof pipes. In particular, when dew condensation on the periphery of the opening of the refrigerator need not be prevented because an outside-air humidity is low, a moisture-condensation-proof pipe arranged on a position such as the rear surface of the refrigerator where dew condensation easily occurs on a clearance between the rear surface of the refrigerator and a wall therearound and where heat insulativity is relatively good and a heat load in rooms is not easily generated is selected so as to make it possible to efficiently suppress the heat load.
The present invention is the refrigerator characterized in that the internal diameter of the pipe of the main condenser is set to 4 mm or more, and the internal diameter of the moisture-condensation-proof pipe is less than 4 mm. For this reason, the internal diameter of the pipe of the main condenser in which a ratio of a gaseous cooling medium is high and a flow rate is relatively high is set to be large, i.e., 4 mm or more to reduce a pressure loss, and the internal diameter of the moisture-condensation-proof pipe in which a ratio of liquid cooling medium is high is set to be less than 4 mm to reduce an internal volume to make it possible to suppress an amount of cooling medium.
In particular, the internal volume in the moisture-condensation-proof pipes is reduced to reduce an amount of cooling medium accumulated in an unused moisture-condensation-proof pipe when a plurality of moisture-condensation-proof pipes are switched to unused states, so that a problem of shortage of an amount of circulated cooling medium of the refrigerating cycle can be avoided.
Since the present invention is the refrigerator characterized in that a moisture-condensation-proof pipe used when the refrigerator is operated under the normal condition is manually selected, depending on installation environments of the refrigerator, for example, only some moisture-condensation-proof pipe that causes dew condensation as a problem in terms of appearance is used to make it possible to more efficiently arbitrarily adjust and suppress a heat load caused by the moisture-condensation-proof pipe.
The present invention is the refrigerator in which, when the refrigerator is operated under a low-outside-air temperature condition, an air-cooling fan of the main condenser is stopped, and a plurality of moisture-condensation-proof pipes are used. For this reason, a problem of shortage of an amount of circulated cooling medium of the refrigerating cycle caused by an excessive amount of cooling medium accumulated in the main condenser can be avoided.
As described above, according to the present invention, a refrigerator includes a refrigerating room, a freezing room, a refrigerating cycle, an evaporator serving as a constituent element of the refrigerating cycle, an evaporator fan that supplies cold air generated by the evaporator to the refrigerating room and the freezing room, a warming heater to defrost the evaporator, a refrigerating room damper that shields the cold air supplied from the evaporator to the refrigerating room, and a freezing room damper that shields the cold air supplied from the evaporator to the freezing room, wherein the refrigerator includes an FC cooling mode in which the freezing room damper is opened, the refrigerating room damper is closed, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the freezing room, a PC cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the refrigerating room, an off cycle cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the evaporator fan is operated while the refrigerating cycle is stopped to exchange heat between the evaporator and air in the refrigerating room, and an off cycle defrost mode in which, while the warming heater is energized, the freezing room damper is closed, the refrigerating room damper is opened, and the evaporator fan is operated while the refrigerating cycle is stopped to melt and remove frost adhering to the evaporator, and after an output of the warming heater is selected based on an amount of food stored in the refrigerating room, the off cycle defrost mode is performed. Thus, a time required for the off cycle defrost can be appropriately controlled, the refrigerating room and the freezing room can be suppressed from increasing in temperature in execution of the off cycle defrost, and electric power of the warming heater required for defrosting is reduced to make it possible to achieve energy saving of refrigerator.
The present invention is the refrigerator characterized in that, whether the off cycle defrost mode can be performed is determined immediately before the PC cooling mode is started, the off cycle defrost mode can be performed at a timing at which a relatively high temperature is set immediately before the refrigerating room is cooled, an amount of heat of off cycle defrost supplied to the evaporator is increased to make it possible to further reduce electric power of the warming heater required for defrosting.
The refrigerator according to the present invention includes a PCC temperature sensor that detects a temperature of the refrigerating room, and a DFP temperature sensor that is arranged at a position higher than that of the PCC temperature sensor and detects a temperature of the upper part of the refrigerating room, wherein, based on a difference between a change in temperature of the PCC temperature sensor and a change in temperature of the DFP temperature sensor in the PC cooling mode or the off cycle cooling mode, an amount of food stored in the refrigerating room is detected. For this reason, an amount of heat held by the food stored in the refrigerating room can be directly estimated, and an output of the warming heater is accurately adjusted to make it possible to further reduce electric power of the warming heater required for defrosting.
As described above, according to the present invention, a refrigerator includes a refrigerating room, a freezing room, a refrigerating cycle, an evaporator serving as a structural element of the refrigerating cycle, an evaporator fan that supplies cold air generated by the evaporator to the refrigerating room and the freezing room, a refrigerating room damper that shields the cold air supplied from the evaporator to the refrigerating room, a freezing room damper that shields the cold air supplied from the evaporator to the freezing room, an FCC temperature sensor that detects a temperature of the freezing room, a PCC temperature sensor that detects a temperature of the refrigerating room, and a DFP temperature sensor that is arranged at a position higher than the PCC temperature sensor and detects a temperature of an upper part of the refrigerating room, wherein the refrigerator includes an FC cooling mode in which the freezing room damper is opened, the refrigerating room damper is closed, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the freezing room, a PC cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the refrigerating room, and an off cycle cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the evaporator fan is operated while the refrigerating cycle is stopped to exchange heat between the evaporator and air in the refrigerating room, and whether the FC cooling mode and the PC cooling mode are turned off/on is determined based on a detected temperature of the FCC temperature sensor or the PCC temperature sensor, and whether the off cycle cooling mode is turned on/off is determined based on a detected temperature of the DFP temperature sensor. Thus, an operation time for PC cooling can be appropriately secured.
According to this, an operation time for the off cycle cooling is controlled based on the DFP temperature sensor arranged in the upper part of the refrigerating room having a relatively large change in temperature to make it possible to accurately adjust a rate of the off cycle cooling and the PC cooling for cooling the refrigerating room. For this reason, the operation time for the PC cooling can be appropriately secured.
The present invention is the refrigerator characterized in that, when a detected temperature of the FCC temperature sensor or the PCC temperature sensor increases, the FC cooling mode and the PC cooling mode are performed in preference to the off cycle cooling mode. For this reason, reduction of operation times for the PC cooling and the FC cooling caused by the off cycle cooling can be suppressed, and changes in temperature of the refrigerating room and the freezing room can be suppressed. According to this, with an increase in detected temperature of the PCC temperature sensor or the FCC temperature sensor, even the off cycle cooling is stopped, and the operation is preferentially switched to the PC cooling or the FC cooling to make it possible to properly secure operation times for the PC cooling and the FC cooling, so that changes in temperature of the refrigerating room and the freezing room can be suppressed.
Since the present invention is the refrigerator characterized in that an OFF temperature of the DFP temperature sensor that detects the end of the off cycle cooling mode is set to be higher than an ON temperature of the PCC temperature sensor that detects the start of the PC cooling mode. The upper part of the refrigerating room can be suppressed from being over-cooled by the off cycle cooling, and the upper part of the refrigerating room can be suppressed from changing in temperature. According to this, the off cycle cooling is controlled while keeping the temperature of the DFP temperature sensor arranged in the upper part of the refrigerating room having a relatively high temperature at a temperature relatively higher than that of the PCC temperature sensor to make it possible to suppress the upper part of the refrigerating room from increasing in temperature.
The refrigerator according to the present invention includes a compressor serving as a structural element of a refrigerating cycle, an upper machine chamber accommodating the compressor disposed in the upper part of the refrigerating room, and a duct that is adjacent to the upper machine chamber and in which cold air cooling the refrigerating room is circulated. For this reason, a temperature of the cold air cooling the refrigerating room can be increased, and a variation in temperature of the upper part of the refrigerating room can be further suppressed. According to this, the duct is formed on the wall surface of the refrigerating room adjacent to the upper machine chamber having a temperature higher than that of outside air to increase the temperature of cold air cooling the refrigerating room in off cycle cooling and PC cooling, in particular, a temperature of the cold air cooling the upper part of the refrigerating room, so that the upper part of the refrigerating room is avoided from being over-cooled to make it possible to further suppress a variation in temperature of the upper part of refrigerating room. Furthermore, since the upper part of the refrigerating room can be avoided from being overcooled, a flow rate of cold air cooling the refrigerating room in the PC cooling state can be increased, and the heat exchange efficiency of the evaporator is improved to make it possible to obtain higher refrigerating cycle efficiency in the PC cooling state.
As described above, according to the present invention, a refrigerator includes a refrigerating room, a freezing room, a refrigerating cycle, an evaporator serving as a structural element of the refrigerating cycle, an evaporator fan that supplies cold air generated by the evaporator to the refrigerating room and the freezing room, a refrigerating room damper that shields the cold air supplied from the evaporator to the refrigerating room, a freezing room damper that shields the cold air supplied from the evaporator to the freezing room, an FCC temperature sensor that detects a temperature of the freezing room, a PCC temperature sensor that detects a temperature of the refrigerating room, and a DFP temperature sensor that is arranged at a position higher than the PCC temperature sensor and detects a temperature of an upper part of the refrigerating room, wherein the refrigerator includes an FC cooling mode in which the freezing room damper is opened, the refrigerating room damper is closed, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the freezing room, a PC cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the refrigerating room, a simultaneous cooling mode in which the freezing room damper is opened, the refrigerating room damper is opened, the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to simultaneously cool the freezing room and the refrigerating room, an off cycle cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the evaporator fan is operated while the refrigerating cycle is stopped to exchange heat between the evaporator and air in the refrigerating room, and performs cooling by combining the FC cooling mode, the PC cooling mode, and the off cycle cooling mode under a normal condition, and performs cooling by combining the simultaneous cooling mode and the FC cooling mode under an overload condition. The PC cooling mode having high efficiency is maintained as long as possible under the normal condition, and under the overload condition, amounts of cooling of the freezing room and the refrigerating room can be automatically appropriately adjusted while continuously cooling the freezing room, and the refrigerating room and the freezing room can be suppressed from increasing in temperature.
According to the present invention, a variable-speed compressor is included, cooling is performed by combining the FC cooling mode, the PC cooling mode, and the off cycle cooling mode when the compressor rotates at a speed lower than a predetermined rotating speed, cooling is performed by combining the simultaneous cooling mode and the FC cooling mode when the compressor rotates at the predetermined rotating speed or more, and an increase in temperature of the evaporator in the simultaneous cooling mode is suppressed to make it possible to suppress the shortage of cooling capacity of the freezing room.
According to the present invention, a reference temperature of the FCC temperature sensor when the simultaneous cooling mode is switched to the FC cooling mode is set to be higher than a reference temperature of the FCC temperature sensor when the cooling operation is started, and the simultaneous cooling mode is maintained as long as possible until the temperature of the freezing room reaches the upper limit of an allowable temperature to make it possible to suppress the shortage of cooling capacity of the refrigerating room.
According to the present invention, slowdown of a cooling rate of the refrigerating room is detected based on temperature behaviors of the PCC temperature sensor and the DFP temperature sensor to shorten a defrosting interval of the evaporator. A decrease in flow rate of the refrigerating room in the simultaneous cooling mode caused by frost adhering to the evaporator can be early recovered, and the shortage of cooling capacity of the refrigerating room can be suppressed.
As described above, the refrigerator according to the present invention includes a first storage room having an opening on a front surface thereof, a second storage room having an opening on a front surface thereof, a refrigerating cycle having a cooler that generates cold air, a cooling fan that circulates the cold air generated by the cooler to the first storage room and a second storage room, a first damper that causes the cold air flowing by the cooling fan to selectively flow into the first storage room, a second damper that causes the cold air flowing by the cooling fan to selectively flow into the second storage room, and a defrosting heater that melts frost adhering to the cooler with heat, wherein the refrigerator includes an off cycle cooling mode in which a cooling fan is operated when the refrigerating cycle is stopped and the first or second damper is opened to cool the first storage room or the second storage room, and a defrosting mode in which frost adhering to the cooler is melted by the defrosting heater, and an interval from the end of the defrosting mode to the next defrosting mode is controlled.
With this configuration, in the refrigerator having the freezing room damper, an amount of frost adhering to the cooler can be predicted to make it possible to adjust a defrosting interval. In this manner, the storage rooms can be prevented from being increased in temperature in vain.
The refrigerator according to the present invention is characterized in that an interval between the end of the defrosting mode and the next defrosting mode is controlled based on the number of times of the off cycle cooling mode from the end of the defrosting mode.
With the above configuration, an amount of adhering frost is predicted by the number of times of the off cycle cooling mode to make it possible to adjust a defrosting interval. In this manner, the storage rooms can be prevented from being increased in temperature in vain.
The refrigerator according to the present invention is characterized in that an interval between the end of the defrosting mode and the next defrosting mode is controlled based on an integrated time of the off cycle cooling mode from the end of the defrosting mode.
With the above configuration, an amount of adhering frost is predicted by the integrated time of the off cycle cooling mode to make it possible to adjust a defrosting interval. In this manner, the storage rooms can be prevented from being increased in temperature in vain.
The refrigerator according to the present invention is characterized in that a first door and a second door that can airtightly close a first storage room and a second storage room, respectively and a door opening/closing detector that detects opening/closing of the first door and the second door are arranged, and an interval between the end of a defrosting mode and the next defrosting mode is controlled depending on the numbers of times of opening of the first door and the second door from the end of the defrosting mode.
With the above configuration, an amount of adhering frost is predicted by combinations between the numbers of times of opening/closing of the doors and the number of times of the off cycle cooling mode or a time for the off cycle cooling mode to make it possible to adjust a defrosting interval. In this manner, frost can be prevented from being left on the cooler, and the storage rooms can be prevented from being increased in temperature in vain.
The refrigerator according to the present invention is characterized in that a first door and a second door that can airtightly close a first storage room and a second storage room, respectively and a door opening/closing detector that detects opening/closing of the first door and the second door are arranged, and an interval between the end of a defrosting mode and the next defrosting mode is controlled depending on an integrated opening time of the first door and the second door from the end of the defrosting mode.
With the above configuration, an amount of adhering frost is predicted by combinations between the integrated door-open time and the number of time of the off cycle cooling mode or a time for the off cycle cooling mode to make it possible to adjust a defrosting interval. In this manner, frost can be prevented from being left on the cooler, and the storage rooms can be prevented from being increased in temperature in vain.
The refrigerator according to the present invention is characterized in that a humidity detector that detects a humidity around the refrigerator is arranged, and an interval between the end of the defrosting mode and the next defrosting mode is controlled by a humidity detected by the humidity detector.
With the above configuration, an amount of adhering frost is predicted by combinations between the humidity around the refrigerator, the number of times of the off cycle cooling mode or a time for the off cycle cooling mode, the number of times of opening/closing of the doors, or the integrated opening time to make it possible to adjust a defrosting interval. In this manner, frost can be prevented from being left on the cooler, and the storage rooms can be prevented from being increased in temperature in vain.
The refrigerator according to the present invention is characterized in that a first temperature adjuster and a second temperature adjuster that set temperatures of the first storage room and the second storage room are arranged, and an interval between the end of the defrosting mode and the next defrosting mode is controlled by set temperatures of the first temperature adjuster and the second temperature adjuster.
With the above configuration, an amount of adhering frost is predicted by combinations between a temperature setting of the refrigerator, the humidity around the refrigerator, the number of times of the off cycle cooling mode or a time for the off cycle cooling mode, the number of times of opening/closing of the doors, or the integrated opening time to make it possible to adjust a defrosting interval. In this manner, frost can be prevented from being left on the cooler, and the storage rooms can be prevented from being increased in temperature in vain.

INDUSTRIAL APPLICABILITY

As described above, in the refrigerator according to the present invention, the plurality of moisture-condensation-proof pipes are connected in parallel to the downstream side of the main condenser through the flow path switching valve to make it possible to arbitrarily adjust and suppress a pressure loss or a heat load caused by the moisture-condensation-proof pipes depending on installation environments and operation states of the refrigerator. For this reason, the present invention can also be applied to other freezing/refrigerating applied products such as commercial refrigerators.
In the refrigerator according to the present invention that includes, in addition to the FC cooling mode and the PC cooling mode, the off cycle cooling mode that cools the refrigerating room during stoppage of the refrigerating cycle and the off cycle defrost mode, an output of the warming heater is adjusted based on an amount of food stored in the refrigerating room to make it possible to appropriately adjust a time for off cycle defrost. For this reason, the refrigerator can also be applied to other freezing/refrigerating applied products such as commercial refrigerators.
In the refrigerator according to the present invention that includes, in addition to the FC cooling mode and the PC cooling mode, the off cycle cooling mode that cools the refrigerating room during stoppage of the refrigerating cycle, an operation time for the PC cooling is appropriately secured, and the refrigerating room can be suppressed from being increased in temperature. For this reason, the refrigerator can also be applied to other freezing/refrigerating applied products such as commercial refrigerators.
The refrigerator according to the present invention includes, in addition to the FC cooling mode and the PC cooling mode, the off cycle cooling mode that cools the refrigerating room during stoppage of the refrigerating cycle, while a simultaneous cooling mode is realized only under an overload condition to maintain an efficient PC cooling mode as long as possible, and the refrigerating room and the freezing room under the overload condition can be suppressed from increasing in temperature. For this reason, the refrigerator can also be applied to other freezing/refrigerating applied products such as commercial refrigerators.
The present invention can provide a refrigerator in which the interior of the refrigerator is cooled during stoppage of a compressor, and storage rooms can be efficiently cooled by changing an interval of defrosting operations. Thus, the present invention is useful as household and commercial refrigerators or the like having various types and sizes.

REFERENCE MARKS IN THE DRAWINGS

1: first moisture-condensation-proof pipe
2: second moisture-condensation-proof pipe
3: flow path switching valve
4: meeting point
5: dryer
6: aperture diaphragm
11: refrigerator
12: casing
13: door
14: leg
15: lower machine chamber
16: upper machine chamber
17: refrigerating room
18: freezing room
19: compressor
20: evaporator
21: main condenser
22: partition wall
23: condenser fan
24: evaporating dish
25: bottom plate
26: intake
27: outlet
28: communicating air trunk
30: evaporator fan
31: freezing room damper
32: refrigerating room damper
33: duct
34: FCC temperature sensor
35: PCC temperature sensor
36: DFP temperature sensor
37: moisture-condensation-proof pipe
38: dryer
39: aperture diaphragm
41: moisture-condensation-proof pipe
42: dryer
43: aperture diaphragm
44: warming heater
50: evaporator fan
51: freezing room damper
52: refrigerating room damper
53: duct
54: FCC temperature sensor
55: PCC temperature sensor
56: compressor
57: evaporating dish
60: compressor
61: main condenser
62: freezing room moisture-condensation-proof pipe
63: refrigerating room moisture-condensation-proof pipe
64: flow path switching valve
65: refrigerating aperture diaphragm
66: refrigerating room evaporator
67: refrigerating room fan
68: freezing aperture diaphragm
69: freezing room evaporator
70: freezing room fan
101: refrigerator
102: freezing room
102a: opening
103: refrigerating room
103a: opening
104: compressor
105: cooler
106: cooling fan
107: freezing room damper
108: refrigerating room damper
109: freezing room sensor
110: refrigerating room sensor
111: defrosting heater
112: cooler sensor
113: freezing room door
114: refrigerating room door
115: freezing room door sensor
116: refrigerating room door sensor
117: humidity sensor
118: controller

Claims

A refrigerator comprising:
a housing including a refrigerating cycle having at least a compressor, an evaporator, and a condenser, wherein

the condenser includes a forced air cooled main condenser, a flow path switching valve connected to a downstream side of the main condenser, and a sub-condenser connected to a downstream side of the flow path switching valve,

the sub-condenser includes a plurality of moisture-condensation-proof pipes connected in parallel, and

a cooling medium flowing into the plurality of moisture-condensation-proof pipes in parallel when the refrigerating cycle is operated under a high-load condition.
The refrigerator according to claim 1, wherein when the refrigerating cycle is operated under a normal condition, a number of moisture-condensation-proof pipes to be used is smaller than that used in a high-load condition.
The refrigerator according to any one of claims 1 to 2, wherein the pipe of the main condenser has an internal diameter of 4 mm or more, and the moisture-condensation-proof pipe has an internal diameter of less than 4 mm.
The refrigerator according to any one of claims 1 and 2, wherein a moisture-condensation-proof pipe used when the operation is performed under the normal condition is manually selected by a user.
The refrigerator according to any one of claims 1 and 2, wherein when the refrigerating cycle is operated under a low-outside-air temperature condition, an air-cooling fan of the main condenser is stopped, and the plurality of moisture-condensation-proof pipes are used.
A refrigerator comprising:
a refrigerating room;

a freezing room;

a refrigerating cycle;

an evaporator serving as a structural element of the refrigerating cycle;

an evaporator fan that supplies cold air generated by the evaporator to the refrigerating room and the freezing room;

a warming heater to defrost the evaporator;

a refrigerating room damper that shields the cold air supplied from the evaporator to the refrigerating room; and

a freezing room damper that shields the cold air supplied from the evaporator to the freezing room, wherein

the refrigerator includes

an FC cooling mode in which the freezing room damper is opened, the refrigerating room damper is closed, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the freezing room,

a PC cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the refrigerating room,

an off cycle cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the evaporator fan is operated while the refrigerating cycle is stopped to exchange heat between the evaporator and air in the refrigerating room, and

an off cycle defrost mode in which, while the warming heater is energized, the freezing room damper is closed, the refrigerating room damper is opened, and the evaporator fan is operated while the refrigerating cycle is stopped to melt and remove frost adhering to the evaporator, the off cycle defrost mode being performed after an output of the warming heater is selected based on an amount of food stored in the refrigerating room.
The refrigerator according to claim 6, wherein whether or not the off cycle defrost mode can be performed is determined immediately before the PC cooling mode is started.
The refrigerator according to any one of claims 6 and 7, further comprising:
a PCC temperature sensor that detects a temperature of the refrigerating room; and

a DFP temperature sensor that is disposed at a position higher than that of the PCC temperature sensor and detects a temperature of an upper part of the refrigerating room,

wherein based on a difference between a change in temperature of the PCC temperature sensor and a change in temperature of the DFP temperature sensor in the PC cooling mode or the off cycle cooling mode, an amount of food stored in the refrigerating room is detected.
A refrigerator comprising:
a refrigerating room;

a freezing room;

a refrigerating cycle;

an evaporator serving as a structural element of the refrigerating cycle;

an evaporator fan that supplies cold air generated by the evaporator to the refrigerating room and the freezing room;

a refrigerating room damper that shields the cold air supplied from the evaporator to the refrigerating room;

a freezing room damper that shields the cold air supplied from the evaporator to the freezing room;

an FCC temperature sensor that detects a temperature of the freezing room;

a PCC temperature sensor that detects a temperature of the refrigerating room; and

a DFP temperature sensor that is disposed at a position higher than the PCC temperature sensor and that detects a temperature of an upper part of the refrigerating room,

wherein the refrigerator includes

an FC cooling mode in which the freezing room damper is opened, the refrigerating room damper is closed, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the freezing room,

a PC cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the refrigerating room, and

an off cycle cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the evaporator fan is operated while the refrigerating cycle is stopped to exchange heat between the evaporator and air in the refrigerating room, and

whether the FC cooling mode and the PC cooling mode are turned off/on is determined based on a detected temperature of the FCC temperature sensor or the PCC temperature sensor, and whether the off cycle cooling mode is turned on/off is determined based on a detected temperature of the DFP temperature sensor.
The refrigerator according to claim 9, wherein when a detected temperature of the FCC temperature sensor or the PCC temperature sensor increases, the FC cooling mode and the PC cooling mode are performed in preference to the off cycle cooling mode.
The refrigerator according to any one of claims 9 and 10, wherein an OFF temperature of the DFP temperature sensor that detects an end of the off cycle cooling mode is set to be higher than an ON temperature of the PCC temperature sensor that detects a start of the PC cooling mode.
The refrigerator according to any one of claims 9 and 10, further comprising:
a compressor serving as a structural element of the refrigerating cycle, an upper machine chamber accommodating the compressor disposed in an upper part of the refrigerating room; and

a duct adjacent to the upper machine chamber, and cold air for cooling the refrigerating room flowing therethrough.
A refrigerator comprising:
a refrigerating room;

a freezing room;

a refrigerating cycle;

an evaporator serving as a structural element of the refrigerating cycle;

an evaporator fan that supplies cold air generated by the evaporator to the refrigerating room and the freezing room;

a refrigerating room damper that shields the cold air supplied from the evaporator to the refrigerating room;

a freezing room damper that shields the cold air supplied from the evaporator to the freezing room;

an FCC temperature sensor that detects a temperature of the freezing room;

a PCC temperature sensor that detects a temperature of the refrigerating room; and

a DFP temperature sensor that is disposed at a position higher than the PCC temperature sensor and detects a temperature of an upper part of the refrigerating room,

wherein the refrigerator includes

an FC cooling mode in which the freezing room damper is opened, the refrigerating room damper is closed, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the freezing room,

a PC cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to cool the refrigerating room,

a simultaneous cooling mode in which the freezing room damper is opened, the refrigerating room damper is opened, the cold air generated by the evaporator is supplied while the refrigerating cycle is operated to simultaneously cool the freezing room and the refrigerating room,

an off cycle cooling mode in which the freezing room damper is closed, the refrigerating room damper is opened, and the evaporator fan is operated while the refrigerating cycle is stopped to exchange heat between the evaporator and air in the refrigerating room, and

the refrigerator performs cooling by combining the FC cooling mode, the PC cooling mode, and the off cycle cooling mode under a normal condition, and performs cooling by combining the simultaneous cooling mode and the FC cooling mode under an overload condition.
The refrigerator according to claim 13, further comprising a variable-speed compressor, wherein
cooling is performed by combining the FC cooling mode, the PC cooling mode, and the off cycle cooling mode when the compressor rotates at a speed lower than a predetermined rotating speed, and
cooling is performed by combining the simultaneous cooling mode and the FC cooling mode when the compressor rotates at the predetermined rotating speed or more.
The refrigerator according to any one of claims 13 and 14, wherein a reference temperature of the FCC temperature sensor when the simultaneous cooling mode is switched to the FC cooling mode is set to be higher than a reference temperature of the FCC temperature sensor when the cooling operation is started.
The refrigerator according to any one of claims 13 and 14, wherein slowdown of a cooling rate of the refrigerating room is detected based on temperature behaviors of the PCC temperature sensor and the DFP temperature sensor to shorten a defrosting interval of the evaporator.
A refrigerator comprising:
a first storage room having an opening on a front surface thereof;

a second storage room;

a refrigerating cycle having a cooler that generates cold air;

a cooling fan that circulates the cold air generated by the cooler to the first storage room and the second storage room;

a first damper that allows the cold air flow caused by the cooling fan to flow selectively into the first storage room;

a second damper that allows the cold air flow caused by the cooling fan to flow selectively into the second storage room; and

a defrosting heater that melts frost adhering to the cooler with heat, wherein

the refrigerator includes

an off cycle cooling mode in which the cooling fan is operated while the refrigerating cycle is stopped and the first or second damper is opened to cool the first storage room or the second storage room, and

a defrosting mode in which frost adhering to the cooler is melted by the defrosting heater, and wherein the interval from the end of the defrosting mode to the next defrosting mode can be controlled.
The refrigerator according to claim 17, wherein the interval between the end of the defrosting mode and the next defrosting mode is controlled based on a number of the off cycle cooling modes done from the end of the defrosting mode.
The refrigerator according to claim 17, wherein the interval between the end of the defrosting mode and the next defrosting mode is controlled based on an integrated time of the off cycle cooling modes done from the end of the defrosting mode.
The refrigerator according to any one of claims 17 to 19, further comprising:
a first door and a second door that can airtightly close the first storage room and the second storage room, respectively; and

a door opening/closing detector that detects opening/closing of the first door and the second door, wherein

the interval between the end of a defrosting mode and the next defrosting mode is controlled depending on a number of times of opening of the first door and the second door from the end of the defrosting mode.
The refrigerator according to any one of claims 17 to 19, further comprising:
a first door and a second door that can airtightly close the first storage room and the second storage room, respectively; and

a door opening/closing detector that detects opening/closing of the first door and the second door, wherein

the interval between the end of a defrosting mode and the next defrosting mode is controlled depending on an integrated opening time of the first door and the second door from the end of the defrosting mode.
The refrigerator according to any one of claims 17 to 19, further comprising a humidity detector that detects a humidity around the refrigerator, wherein
the interval between the end of the defrosting mode and the next defrosting mode is controlled by a humidity detected by the humidity detector.
The refrigerator according to any one of claims 17 to 19, further comprising a first temperature adjuster and a second temperature adjuster that set temperatures of the first storage room and the second storage room, wherein
the interval between the end of the defrosting mode and the next defrosting mode is controlled by set temperatures of the first temperature adjuster and the second temperature adjuster.