CN110219152B

CN110219152B - Clothes drying equipment with heat pump

Info

Publication number: CN110219152B
Application number: CN201910148327.6A
Authority: CN
Inventors: J·A·鲁伊斯贝尔梅霍
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2018-03-02
Filing date: 2019-02-28
Publication date: 2023-03-14
Anticipated expiration: 2039-02-28
Also published as: CN110219152A; PL3533920T3; ES2724363A1; EP3533920B1; EP3533920A1

Abstract

Laundry drying apparatus (1) comprising a heat pump (11), said heat pump (11) comprising a compressor (12), a condenser (9), an expansion device (13) and an evaporator (6) connected by fluid conduits (14-17) carrying a working fluid (F); and comprising a control unit (18) connected to the compressor (12), said control unit (18) being adapted to operate the compressor (12) in a first and a second operation mode during the drying cycle, wherein the compressor (12) is an AC rotary compressor (12), in the first operation mode the AC rotary compressor (12) being continuously on, and in the second operation mode the AC rotary compressor (12) being alternately on and off. Furthermore, a method for operating a laundry drying apparatus (1) comprising a heat pump (11) comprising an AC rotary compressor (12) in a first and a second mode of operation is disclosed.

Description

Clothes drying equipment with heat pump

Technical Field

The present invention relates to a laundry drying apparatus comprising a heat pump comprising a compressor, a condenser, an expansion device and an evaporator connected by fluid conduits carrying a working fluid, and comprising a control unit connected to the compressor, said control unit being adapted to operate the compressor. The invention also relates to a method for operating a laundry drying appliance comprising a heat pump comprising a compressor, a condenser, an expansion device and an evaporator connected by fluid conduits carrying a working fluid. The invention is particularly suitable for use in domestic appliances.

Background

The use of heat pumps in laundry drying appliances is well known.

For example, WO 2007/077084 A1 discloses a household appliance for care of laundry items, in particular a tumble dryer. The appliance comprises a container for receiving laundry items, a process air supply connected to the container to allow process air to flow through the container, and a first heat exchanger coupled to the process air supply and designed to dry process air exiting the container.

EP 2 985 466 A1 discloses a rotary compressor comprising a cylindrical shell, a cylindrical roller housed in the shell, a motor shaft guided through the roller having a cam for rolling the roller along the side wall of the shell, and a discharge port guided through the bottom cover. A household appliance, in particular a laundry care appliance, comprises a heat pump.

In order to vary the energy consumption of the heat pump, it is known to use a BLDC driven compressor and vary the speed of the BLDC driven compressor, i.e. the rotational speed of the BLDC motor driving the compressor. However, the BLDC driven compressors have a disadvantage in that they are expensive and use additional components such as an inverter.

Disclosure of Invention

It is an object of the present invention to at least partially overcome the problems associated with the prior art. A particular object of the invention is to be able to vary the energy consumption of a heat pump in a particularly cost-effective manner.

This object is achieved according to the features of the invention. Advantageous embodiments can be found in, for example, the description.

This object is achieved by a laundry drying apparatus comprising a heat pump comprising a compressor, a condenser, an expansion device and an evaporator connected by fluid conduits carrying a working fluid, and comprising a control unit connected to the compressor, the control unit being adapted to operate the compressor during a drying cycle in a first mode of operation and in a second mode of operation, wherein the compressor is an AC rotary compressor, in the first mode of operation the AC rotary compressor being continuously on, and in the second mode of operation the AC rotary compressor being alternately on and off.

An advantage of the laundry drying appliance is that in the first operating mode, a particularly fast drying ("speed mode") can be achieved, whereas in the second operating mode, a particularly energy-efficient drying ("economy mode") can be achieved. The operation mode may be selected by a user and/or may be automatically selected by the laundry drying apparatus. The energy saving effect of the second operation mode is achieved by not operating the AC rotary compressor in its off state. The thermal inertia of the condenser and evaporator then still allows the laundry to dry in the off state. If the drying efficiency in the off state falls below a predetermined level, the compressor is turned on again. Thus, the alternating on and off of the AC rotary compressor achieves a reduction in the total energy consumption during the drying cycle.

Another advantage of the laundry drying apparatus is that it is more cost-effective than using a BLDC driven compressor. While BLDC driven compressors have higher efficiency, they are also more expensive and require additional components to operate, such as electronic inverters. The laundry drying apparatus using the AC rotary compressor is also more durable.

The laundry drying apparatus may be a dryer or a washer/dryer combination. The laundry drying appliance may be a household or domestic appliance.

In particular, the AC rotary compressor or the AC driven rotary compressor may have a fixed rated speed in its on-state. An AC rotary compressor is a compressor driven by an AC motor.

A heat pump may include a compressor, a condenser, an expansion device (e.g., a capillary tube or an expansion valve), and an evaporator connected in series by fluid conduits carrying a working fluid (refrigerant). Thus, the heat pump provides a working fluid circuit for flowing a working fluid in that direction through the compressor, condenser, expansion device, and evaporator. The fluid conduit may be or comprise a tube or the like. The tube may be made of copper, aluminum, or the like.

The working fluid may include: flammable refrigerants such as R290, R32 and/or R1270 (propylene) and the like, and/or Hydrofluorocarbons (HFCs) such as R407C and/or R134a and the like. The condenser and evaporator function as heat exchangers located in a process air channel (e.g., an open-loop or closed-loop process air channel). In particular, the condenser may serve as a heater for the process air flowing through the process air channel, while the evaporator may serve as a cooling device to cool the process air. The arrangement and the operating principle of a heat pump for a laundry drying appliance are generally known and will therefore not be described in detail.

The "drying cycle" may be part of the drying process, in particular the drying program. The drying process may include further cycles such as a spin or spin dehydration cycle, an anti-wrinkle cycle, and the like. During the drying cycle, the laundry contained in the laundry chamber of the laundry drying appliance may be dried by introducing warm and dry process air into the laundry chamber and releasing moist process air from the laundry chamber. The laundry chamber may be a rotatable drum. The drying process may have one or more than two drying cycles. If the drying process comprises a plurality of drying cycles, they may be separated by at least one further cycle, for example a spin drying cycle.

The control unit is adapted to selectively switch on and off the AC rotary compressor. The control unit may be a central control unit of the laundry drying appliance controlling the operation of the drying cycle.

In one embodiment, the control unit is adapted to repeatedly switch on and off the AC rotary compressor. This provides the advantage that the drying efficiency can be kept at a high level during the second mode of operation. In particular, there may be two or more time slots for switching the AC rotary compressor on and/or off during the drying cycle. The duration of the time slot may be predefined. Alternatively or additionally, the duration of the time slot may be set based on input from sensors of the laundry drying appliance, such as input from one or more temperature sensors, humidity sensors, etc.

In one embodiment, the control unit is adapted to change the duration of the time slot for switching the AC rotary compressor on and off. This advantageously allows to adjust the level of drying efficiency, for example based on the amount of laundry (e.g. weight), the moisture content of the laundry (e.g. degree of dryness), the type of laundry, the selected duration of the drying cycle or drying program, etc. The time slots for switching on and off the AC rotary compressor may be different, i.e., have different lengths or durations.

In one embodiment, the control unit is adapted to change the duration of the time slot during the drying cycle. This advantageously allows further optimizing the level of drying efficiency.

In one embodiment, the time slot (on or off) is at least three minutes in duration. Varying the duration of the on-time slot and/or the off-time slot may affect the temperature stability and/or the drying time associated with energy consumption.

In one embodiment, the heat pump comprises an open fluid conduit for carrying a working fluid, wherein in its off-state the AC rotary compressor prevents the working fluid from flowing between its high pressure side and its low pressure side, and/or wherein the expansion device is selectively switchable between an open state and a closed state, and the control unit is adapted to open the expansion device when the AC rotary compressor is switched on and to close the expansion device when the AC rotary compressor is switched off. This provides the advantage of a particularly simple, cost-effective and durable arrangement in which the thermal inertia of the evaporator and condenser can be reliably maintained in the switched-off state of the compressor for a relatively long time. An "open fluid conduit" is understood to mean a fluid conduit without a dedicated shut-off device to prevent the flow of working fluid through it. The control unit being adapted to open the expansion device may comprise opening the expansion device or keeping the expansion device open. Similarly, the control unit being adapted to close the expansion device may comprise closing the expansion device or keeping the expansion device closed. Advantageously, the expansion device is an expansion valve.

In one embodiment, the fluid conduit comprises at least one controllable shut-off device, wherein the at least one controllable shut-off device is open when the AC rotary compressor is on during the drying cycle, and wherein the at least one controllable shut-off device is closed when the AC rotary compressor is off during the drying cycle and the at least one controllable shut-off device is open when the AC rotary compressor is on during the drying cycle. This provides the following advantages: the thermal inertia of the evaporator and the condenser can be maintained in a particularly reliable manner even if the compressor and/or the expansion device of the heat pump cannot prevent or effectively prevent the working fluid from flowing through them. The controllable shut-off device can be selectively opened and closed by the control unit. The controllable shut-off device may be a valve. The controllable shut-off device may be connected to the control unit to be selectively switched on and off by the control unit. The fluid conduit including a cut-off device may comprise the cut-off device being located in or between two parts of the fluid conduit and/or may comprise a cut-off device being located between the fluid conduit and a functional component of the heat pump, such as a compressor, an evaporator, a condenser and/or an expansion device.

In one embodiment, the at least one controllable shut-off device comprises a shut-off device located between the expansion device and the evaporator or between the condenser and the expansion device. This advantageously provides a particularly efficient way to prevent the working fluid from flowing in the heat pump, while keeping costs low, especially if the expansion device is not closable.

In one embodiment, the at least one controllable shut-off device comprises a shut-off device located between the AC rotary compressor and the condenser or between the evaporator and the AC rotary compressor. This advantageously provides another particularly effective way to prevent the working fluid from flowing in the heat pump while maintaining low cost, particularly if the high and low pressure sides of the AC rotary compressor are not shut off in their off state.

In one embodiment, the at least one controllable cut-off device comprises two cut-off devices, a first cut-off device being located between the expansion device and the evaporator or between the condenser and the expansion device, and a second cut-off device being located between the evaporator and the AC rotary compressor or between the AC rotary compressor and the condenser. This advantageously provides a particularly effective way to prevent the working fluid from flowing in the heat pump, while keeping costs low, especially if the AC rotary compressor is not fluidly closed between its high pressure side and its low pressure side during its off-state and the expansion device is not closable.

In one embodiment, the at least one controllable shut-off device comprises a first shut-off device between the expansion device and the evaporator or between the condenser and the expansion device, a second shut-off device between the evaporator and the compressor, and a third shut-off device between the compressor and the condenser. This advantageously provides a more efficient way to prevent the working fluid from flowing in the heat pump while keeping costs low, especially if the AC rotary compressor is not fluidly closed between its high pressure side and its low pressure side during its off-state and the expansion device is not closable. The controllable shut-off device may be a valve. The controllable shut-off device may be connected to the control unit to be selectively switched on and off by the control unit.

The object is also achieved by a method for operating a laundry drying appliance comprising a heat pump comprising a compressor, a condenser, an expansion device and an evaporator connected by fluid conduits carrying a working fluid, wherein in a first operating mode the AC rotary compressor is continuously on during a drying cycle and in a second operating mode the AC rotary compressor is alternately on and off during the drying cycle.

The method can be implemented similarly to the drying apparatus comprising the same as described above and with the same advantages.

For example, in one embodiment, when the AC rotary compressor is off, the working fluid is prevented from flowing freely through the heat pump. This enhances the energy saving effect. Preventing the working fluid from freely flowing through the heat pump may include, at least one location of the heat pump (working fluid circuit), the working fluid being blocked or at least severely prevented from flowing.

Drawings

The above-mentioned features and advantages of the present invention and their embodiments will now be schematically described in more detail by means of at least one embodiment in one or more of the figures.

Fig. 1 shows a functional block diagram of a laundry drying appliance 1 according to the present invention.

Detailed Description

The laundry drying apparatus 1 has a closed loop process air circuit 2 comprising a rotating drum 3 for holding laundry. The outlet port of the drum 3 is connected to a lint filter 4 via a section (long dashed line) of a process air channel 5. The lint filter 4 is connected via another section of the process air channel 5 to a first heat exchanger 6. The process air P is guided over the surface of the first heat exchanger 6 where it is cooled so that the moist process air P from the drum 3 condenses. The resulting condensate 7 may be collected in a tray 8. The collected condensate may lead to waste or may be reused, for example for cleaning at least the first heat exchanger 6. The heat exchanger 6 is further connected to a second heat exchanger 9 via another section of the process air channel 5. At the second heat exchanger 9, the dried process air P from the first heat exchanger 6 is heated. The second heat exchanger 9 is connected via another section of the process air channel 5 to a fan 10 for moving the process air P within the process air circuit 2. The fan 10 is connected to the inlet port of the drum 3 via another section of the process air channel 5. Thus, dry and warm process air P is introduced into the drum 3 to dry the laundry. The fan 10 may also be placed at another location within the process air circuit 2, for example between the drum 3 and the lint filter 4. The process air circuit 2 may have additional components (not shown), such as additional electric heaters, additional fans, additional lint filters, etc.

The first heat exchanger 6 and the second heat exchanger 9 are also components of a heat pump 11 of the laundry drying appliance 1. The first heat exchanger 6 corresponds to an evaporator of the heat pump 11, and the second heat exchanger 9 corresponds to a condenser thereof. The heat pump 11 also includes an AC rotary compressor 12 and an expansion device 13, such as a capillary tube or an expansion valve.

The high pressure side or port of the AC rotary compressor 12 is connected to the condenser (second heat exchanger 9) via a first fluid conduit 14 for the working fluid F. The condenser 9 is further connected to the high pressure side of the expansion device 13 via a second fluid conduit 15 for the working fluid F. The low pressure side of the expansion device 13 is connected to the evaporator (first heat exchanger 6) via a third fluid conduit 16 for the working fluid F. The evaporator 6 is connected to the low pressure side of the AC rotary compressor 12 via a fourth fluid conduit 17 for the working fluid F.

When the AC rotary compressor 12 is switched on, the pressurized working fluid F flows from the high pressure side of the AC rotary compressor 12 through the first conduit 14, through the condenser 9, through the second conduit 15, through the expansion device 13 (expanded at its low pressure side), through the third conduit 16, through the evaporator 6 and through the fourth conduit 17 to the low pressure side of the AC rotary compressor 12. In the AC rotary compressor 12, the working fluid F is compressed and then discharged again at the high pressure side of the AC rotary compressor 12.

When the AC rotary compressor 12 is switched off, the working fluid F is no longer moved by the AC rotary compressor 12, but can be moved to balance the pressure between the high pressure section of the heat pump 11 and the low pressure section of the heat pump 11 if not prevented. The

conduits

14 and 15 carrying the high-pressure working fluid F are shown in dotted lines, while the

conduits

16 and 17 carrying the low-pressure working fluid F are shown in dashed lines.

The laundry drying apparatus 1 further comprises a control unit 18 controlling the operation of the AC rotary compressor 12, in particular for switching the AC rotary compressor 12 on and off. The control unit 18 may also control the operation of the drum 3 and the fan 10, as well as other components of the laundry drying appliance 1.

The control unit 18 is adapted to operating the AC rotary compressor 12 during a drying cycle in a first operation mode and in a second operation mode, wherein in the first operation mode the AC rotary compressor 12 is continuously on and in the second operation mode the AC rotary compressor 12 is alternately, in particular repeatedly, on and off. The control unit 18 may be adapted to vary the duration of the time slots for switching the AC rotary compressor 12 on and off. The control unit 18 may also be adapted to vary the duration of the time slot during the drying cycle.

In a first variant of the laundry drying appliance 1, the heat pump 11 comprises open ducts 14 to 17. In order to prevent the working fluid F from flowing to balance the pressure when the AC rotary compressor 12 is turned off, the AC rotary compressor 12 is implemented such that, in the turned-off state, its high-pressure side and its low-pressure side are hermetically sealed from each other. Thus, the disconnected AC rotary compressor 12 prevents the working fluid F from flowing from its high pressure side to its low pressure side. Additionally or alternatively, the expansion device 13 may be selectively switched between an open state and a closed state by the control unit 18, and the control unit 18 is adapted to open the expansion device 13 when the AC rotary compressor 12 is switched on and to close the expansion device 13 when the AC rotary compressor 12 is switched off. Thus, the expansion device 13 prevents the working fluid F from flowing from its high-pressure side to its low-pressure side.

In a second variant of the laundry drying apparatus 1, the laundry drying apparatus 1 comprises a controllable first cut-off device 19 connected to the control unit 18, the first cut-off device 19 being located between the expansion device 13 and the evaporator 6. The control unit 18 controls the first cut-off device 19 such that it is opened when the AC rotary compressor 12 is turned on, and it is closed when the AC rotary compressor 12 is turned off during the drying cycle. This variant may be particularly advantageous if the high-pressure side and the low-pressure side of the AC rotary compressor 12 are hermetically sealed from each other in the disconnected state, but the expansion device 13 is not closable, i.e. always open. Alternatively, the controllable first shut-off device 19 may be located between the condenser 9 and the expansion device 13.

In a third variant of the laundry drying appliance 1, the laundry drying appliance 1 additionally comprises a controllable second cut-off device 20 or a controllable third cut-off device 21 connected to the control unit 18. The second cut-off device 20 is located between the evaporator 6 and the low pressure side of the AC rotary compressor 12. The third cut-off 21 is located between the high pressure side of the AC rotary compressor 12 and the condenser 9. The control unit 18 controls the second cut-off 20 or the third cut-off 21 such that it is opened when the AC rotary compressor 12 is turned on, and it is closed when the AC rotary compressor 12 is turned off during the drying cycle. This variant may be particularly advantageous if the high-pressure side and the low-pressure side of the AC rotary compressor 12 are in communication with each other in the disconnected state and the expansion device 13 is not closable.

In a fourth variant of the laundry drying appliance 1, the laundry drying appliance 1 comprises a controllable first cut-off device 19, a controllable second cut-off device 20 and a controllable third cut-off device 21. This variant prevents the working fluid from moving particularly reliably during the switched-off state of the AC rotary compressor 12, for example if the high-pressure side and the low-pressure side of the AC rotary compressor 12 are in communication with one another in the switched-off state and the expansion device 13 is not closable.

Of course, the invention is not limited to the described embodiments.

For example, the laundry drying apparatus 1 may not have the lint filter 4.

Furthermore, the laundry drying appliance 1 may comprise an additional fan for cooling the AC rotary compressor 12.

List of reference numerals

1 clothes drying apparatus

2 process air circuit

3 roller

4 cotton linter filter

5 Process air channel

6 first heat exchanger/evaporator

7 condensate

8 tray

9 second Heat exchanger/condenser

10 Fan

11 heat pump

12AC rotary compressor

13 expansion device

14 first pipeline

15 second conduit

16 third pipeline

17 fourth pipeline

18 control unit

19 first cutting device

20 second cutting device

21 third cutting device

F working fluid

P treating air

Claims

1. A laundry drying apparatus (1),

-comprising a heat pump (11) comprising a compressor (12), a condenser (9), an expansion device (13) and an evaporator (6) connected by fluid conduits (14-17) carrying a working fluid (F), and

-comprising a control unit (18) connected to the compressor (12), the control unit (18) being adapted to operate the compressor (12) in a first and a second operation mode during a drying cycle,

wherein the content of the first and second substances,

-the compressor (12) is an AC rotary compressor (12),

-in a first operation mode, the AC rotary compressor (12) is continuously switched on, and

-in a second operation mode, the AC rotary compressor (12) is alternately switched on and off,

-the heat pump (11) comprises an open fluid conduit (14-17) for carrying a working fluid (F), wherein the AC rotary compressor (12) in its off-state prevents the working fluid (F) from flowing between its high pressure side and its low pressure side, and/or the expansion device (13) is selectively switchable between an open state and a closed state, and the control unit (18) is adapted to open the expansion device (13) when the AC rotary compressor (12) is on and to close the expansion device (13) when the AC rotary compressor (12) is off,

and/or

-the fluid conduit (14-17) comprises at least one controllable shut-off device (19-21), wherein,

the at least one controllable shut-off device (19-21) is open when the AC rotary compressor (12) is switched on during a drying cycle, and

the at least one controllable shut-off device (19-21) is closed when the AC rotary compressor (12) is switched off during a drying cycle, and the at least one controllable shut-off device (19-21) is open when the AC rotary compressor (12) is switched on during a drying cycle.

2. The laundry drying apparatus (1) according to claim 1, wherein said control unit (18) is adapted to repeatedly switch said AC rotary compressor (12) on and off.

3. The laundry drying appliance (1) according to claim 1 or 2, wherein said control unit (18) is adapted to vary the duration of a time slot for switching said AC rotary compressor (12) on and off.

4. The laundry drying apparatus (1) according to claim 3, wherein said control unit (18) is adapted to vary the duration of said time slot during a drying cycle.

5. Laundry drying apparatus (1) according to any of claims 1, 2, 4, wherein said at least one controllable shut-off device (19-21) comprises a shut-off device (19) located between the expansion device (13) and the evaporator (6) or between the condenser (9) and the expansion device (13).

6. Laundry drying apparatus (1) according to any of claims 1, 2, 4, wherein said at least one controllable shut-off device (19-21) comprises:

-a first shut-off device (19) between the expansion device (13) and the evaporator (6) or between the condenser (9) and the expansion device (13),

-a second shut-off device (20) between the evaporator (6) and the compressor (12), and

-third shut-off means (21) between the compressor (12) and the condenser (9).

7. Method for operating a laundry drying apparatus (1) comprising a heat pump (11) comprising a compressor (12), a condenser (9), an expansion device (13) and an evaporator (6) connected by fluid conduits (14-17) carrying a working fluid (F), wherein the compressor (12) is an AC rotary compressor (12),

-in a first mode of operation, the AC rotary compressor (12) is continuously switched on during the drying cycle, and,

-in a second mode of operation, the AC rotary compressor (12) is alternately switched on and off during a drying cycle,

-preventing the working fluid (F) from flowing freely through the heat pump (11) when the AC rotary compressor (12) is switched off,

-the heat pump (11) comprises an open fluid conduit (14-17) for carrying a working fluid (F), wherein the expansion device (13) is selectively switchable between an open state and a closed state, and the control unit (18) is adapted to open the expansion device (13) when the AC rotary compressor (12) is switched on and to close the expansion device (13) when the AC rotary compressor (12) is switched off,

and/or

said at least one controllable shut-off device (19-21) is open when the AC rotary compressor (12) is switched on during a drying cycle,