DE102012212159A1 - Front loading exhaust air laundry drying apparatus e.g. exhaust air washer-dryer, has recovery aggregate for transferring heat from channel to passage and designed as heat pump that comprises vaporizer, condenser, compressor and valve - Google Patents

Abstract

The apparatus (1) has an air intake passage (3) leading from an outside (A) to a heatable laundry treatment space (2). An air outlet channel (5) leads to the outside from the laundry treatment space. A heat recovery aggregate transfers heat from the outlet channel to the intake passage. An additional heating system (7) is arranged at the intake passage. The heat recovery aggregate is designed as a controllable heat pump i.e. gas process heat pump, that comprises a vaporizer (8), a condenser (9), a compressor (10) i.e. rotation speed-controllable compressor, and an expansion valve (11). The heatable laundry treatment space is designed as a rotatable laundry drum.

Description

The invention relates to an exhaust air drying device comprising an air inlet duct leading from the outside to a heatable laundry treatment room, an air outlet duct leading outwardly from the laundry treatment room, a heat recovery unit for transferring heat from the air outlet duct to the air inlet duct and an auxiliary heater disposed on the air inlet duct , The invention further relates to a method for operating such an exhaust air laundry drying device.

For example DE 197 37 075 A1 an exhaust air drying device of the type mentioned is known in which the heat recovery unit is an air / air heat exchanger, which is on the one hand with air of the air inlet channel and on the other hand with air of the air outlet channel flows. The air / air heat exchanger is arranged in terms of flow before an additional heating.

By replacing the air / air heat exchanger with a heat pump efficiency of the exhaust air dryer can be further increased. The efficiency depends on a predetermined design or tuning of the heat pump, the efficiency is the higher the better the heat pump is adapted to a temperature or to a temperature difference of the process air and thus the air ducts. Conversely, the efficiency is reduced when fluctuations in the performance of the exhaust air dryer, especially in its temperature or temperature differences, occur. Such fluctuations may occur, for example, as a function of a load and a humidity of the laundry located in the laundry treatment room, as well as due to an operation of the additional heating. In particular, due to an additional heat input generated by the additional heating, overheating of the evaporator can become so high that the efficiency drops significantly.

DE 10 2007 062 776 A1 discloses an exhaust air dryer with a drying chamber, a process air duct, in which a heating for heating the process air is and the heated process air can be guided by means of a blower in the drying chamber, a motor and a controller, which dryer is set up for operation while receiving an electric Power which never exceeds a predetermined value Pmax. The exhaust air dryer has means which are set up in such a way that, during operation, the dryer receives at least in phases the electrical power corresponding to the predetermined value Pmax. The dryer may include a heat pump cycle with an evaporator, a liquefier, a compressor, and an expansion valve or throttle valve.

Out US 2010/0077787 A1 For example, a circulating-air condensing clothes dryer with a compressor heat pump is known in which a 'normal' drying operation and an 'energy-saving' drying operation can be realized by operating the compressor or compressor at different speeds. If a temperature during the 'energy-saving' drying operation falls below a predetermined threshold, the speed may be increased to achieve a temperature increase.

DE 10 2007 016 077 A1 discloses a method of operating a circulating air condensing clothes dryer with a drying chamber for articles to be dried, a process air circuit in which a heater for heating the process air is and the heated process air is guided by means of a first blower over the objects to be dried, an air-air Heat exchanger and a heat pump circuit with an evaporator, a compressor and a condenser, the heat pump circuit and the heater with a heating capacity in the process air circuit act. The heating capacity is regulated depending on at least one parameter of the heat pump cycle. The document also relates to a corresponding condensation clothes dryer. To regulate the heating power, the power consumption of the compressor, which determines the operation of the heat pump cycle and thus in particular acting in the process air circuit heat output of the condenser of the heat pump can be controlled. By appropriate regulation of the heating power through the refrigeration cycle of the heat pump improved tuning can be achieved and thus a further improved relation between energy consumption and drying time in a condensation hybrid dryer can be made possible.

It is the object of the present invention to provide a possibility for exhaust air drying laundry with a heater (hereinafter called "auxiliary heater") and a heat exchanger unit, which at least partially overcomes the disadvantages of the prior art and in particular a high efficiency over a wider range of Can maintain operating conditions. It is another object to provide an uninterruptible opportunity for exhaust air dryer drying.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims and the following description.

The object is achieved by an exhaust air dryer having an air inlet duct leading from outside to a heatable laundry treatment room, an air outlet duct leading outwards from the laundry treatment room, a heat recovery unit for transferring heat from the air outlet duct to the air inlet duct and one at the Air inlet duct arranged additional heater, the heat recovery unit is a (power) controllable heat pump.

By the performance of the heat pump according to the invention can be regulated, their operation can be adapted to different operating and environmental conditions of the exhaust air dryer. This allows in particular a particularly energy-efficient operation of the exhaust air dryer in a variety of conditions. In addition, it can also be avoided in particular to have to completely stop the power input, whereby drying no longer needs to be interrupted.

Under a performance of the heat pump can be understood in particular a einbringbare in the associated cooling circuit thermal performance. Alternatively or additionally, a power of the heat pump may be understood as meaning a (primary) power (for example an electric power of an electric drive motor) which is input to a drive of the heat pump. In particular, there may be a known relationship between the (primary) introduced into the drive power and its resulting thermal performance. The primary power and the thermal power can therefore also be used interchangeably, unless otherwise stated in the context.

A unit arranged on an air inlet duct or an air outlet duct may in particular be understood to mean a unit which is arranged at least partially in this air duct. Alternatively, this may be understood to mean a unit which is fluidically coupled to this air duct, e.g. is arranged in a parallel arranged air duct.

The exhaust air dryer can be a (combined) exhaust air washer dryer or a pure exhaust air dryer.

The laundry treatment room may in particular be a rotatable laundry drum. The exhaust air dryer may be in particular a front loader.

The additional heating may be, for example, a current-driven heating (resistance heating) or a gas-operated additional heating. The additional heater may be an at least partially autonomously operable auxiliary heater for even lower energy consumption, e.g. operated by solar cells.

It is a preferred embodiment that the heat pump has a drive which generates a higher thermal power than the additional heater. This embodiment has the advantage that the auxiliary heating does not need to be activated for energy-saving operating modes, but the heat pump is sufficient for a drying operation. In particular, the heat pump may then be operated particularly effectively.

It is still a preferable configuration that a sum of the thermal powers of the heat source of the heat pump (e.g., an evaporator of a compression heat source) and the auxiliary heater may be made higher or higher than a maximum allowable electric power.

It is a further preferred embodiment that a maximum permissible electrical connection power is approximately 2 kW to 2.5 kW. This is advantageous, for example, if a supply network to which the exhaust air dryer is connectable, a voltage of about 230 V and a maximum current of 10 A supplies.

It is also a preferred embodiment that the heat pump has an evaporator, a condenser, a drive in the form of a compressor and a relaxation device and that the condenser is thermally coupled to the air inlet duct and the evaporator is thermally coupled to the air outlet duct. Due to the fact that the evaporator is thermally coupled to the air outlet duct, heat is extracted from the air outlet duct or the warm, moist process air (exhaust air) located in the air outlet duct and transferred to the evaporator. Conversely, by thermally coupling the condenser to the air inlet duct, heat can be transferred from the condenser to the air inlet duct or to the process air (fresh air) located in the air inlet duct. Due to the temperatures or temperature differences (and analogous to the pressures or pressure differences) on the evaporator and the condenser, the heat pump cycle is operable. Efficiency of the heat pump depends on these temperatures or temperature differences and can be optimized by design of the elements of the heat pump to the temperatures or temperature differences for given boundary conditions. Such a compressor Heat pump is particularly robust, compact and inexpensive available.

It is also a preferred embodiment that a heat sink of the heat pump, for example in the case of a compressor heat pump of the evaporator, is arranged in the air outlet duct. Thus, heat can be pumped from the warm process air into the heat source effectively by means of the heat pump, also a simple structure is achieved. It is an alternative embodiment that the heat sink in an air duct parallel to the process air duct, in particular air outlet duct to position.

It is also a preferred embodiment that the compressor is a variable speed compressor, so in particular a variable speed motor ("compressor motor") has. For a continuous adjustment of the speed and thus the power of the compressor motor may be in particular a brushless DC motor ("BLDC motor"). The speed may in particular be adjustable between 150 rpm and 350 rpm.

Alternatively or additionally, a compressor heat pump can also be controlled or regulated by setting a flow cross section through the expansion device. By changing the relaxation characteristic, in particular as a function of the activity of the additional heating, the heat pump, in particular its optimal operating point, can be easily adapted to a particularly strong shift of the operating point of the heat pump, in particular due to an operation or an activity of additional heating.

The expansion device may, for example, be or have an expansion valve (also called a throttle valve), and a flow cross-section of the expansion valve (as a variable influencing the expansion characteristic) may be adjustable or controllable depending on the at least one parameter. Thus, the adjustment of the compressor heat pump can also be achieved in a simple and inexpensive way. The expansion valve may in particular be a remotely controllable, in particular a controllable, expansion valve. The expansion valve may in particular be an electronic expansion valve. For operation of the heat pump, the flow cross section of the adjustable expansion valve may be adjustable, in particular, between a smallest flow cross section and a largest flow cross section, both flow cross sections being greater than zero, ie, the expansion valve is not closed even at the smallest flow cross section.

It is still a preferred embodiment that the expansion device comprises a group of several fluidly connected in parallel capillaries, of which at least one capillary depending on the at least one parameter is selectively openable and closable. A flow cross section of the expansion device is then determined by the number of open capillaries, whereby the expansion device consequently has a stepwise adjustable flow cross section. In particular, a capillary can be present as an expansion valve with a flow cross-section fixed in the open state. In particular, all capillaries or all capillaries except a first capillary can optionally be opened and closed.

It is also a preferred embodiment that the expansion device is adjustable in such a way that it (only) between a first operating position and a second operating position is switchable. In this case, therefore, the expansion device has only two adjustable flow cross sections. Such a relaxation device may be particularly simple and inexpensive ausgestaltbar, e.g. by providing only two capillaries.

It is also a preferred embodiment that the expansion device is multistage or continuously adjustable, which can be achieved even more accurate adjustment of the heat pump. For example, the expansion valve may change its flow cross-section gradually or continuously. To operate the heat pump, the flow cross section of the adjustable expansion valve may be adjustable, in particular stepwise or stepwise, between a smallest flow cross section and a largest flow cross section. An overall flow cross-section of the group of several fluidically connected capillaries is simply stepwise or multi-stage adjustable.

It is also a preferred embodiment that the heat pump is a gas process heat pump. The gas-process heat pump may be, for example, a heat pump operating according to the Stirling principle or according to the Vuilleumier principle. For example, its operating frequency can be controlled, e.g. by setting or regulating a heating of the heat pump according to the Vuilleumier principle.

It is still a preferred development that the heat pump is a Peltier heat pump, This can sic example, regulate their operating voltage.

It is still a preferred embodiment that the exhaust air dryer has at least a first mode and a second mode, wherein in the first mode, the heat pump and the auxiliary heater are operated at maximum power and in the second mode, only the heat pump is operated. There may be additional operating modes in addition, in which, for example, the heat pump and the auxiliary heater are operated together, but not together at maximum power.

It is yet another preferred embodiment that the heat pump can be regulated as a function of at least one parameter associated with an activity of the additional heating. A parameter associated with an activity of the additional heating may in particular be an operating parameter of the additional heating. Thus, an adaptation to the operation of the additional heating can be done immediately. For example, a relaxation characteristic of a relaxation device and / or an engine speed of a compressor heat pump may be controllably adjustable as a function of at least one operating parameter of the additional heater.

In particular, it is a preferred development that the heat pump, in particular its power, is adjustable or controllable as a function of a current heating power of the additional heater. The associated with the activity of the additional heating parameters is thus the heating power. This heating power can be regarded in particular as an operating parameter of the additional heater. The heating power may, for example, be represented by an electric power currently consumed by the auxiliary heater, which may be e.g. can be measured by means of a current sensor. Alternatively, the heating power may be represented by a desired power of the additional heater, which can be dispensed with a current sensor.

In addition, it is a preferred development that the heat pump, in particular its power, can be set or regulated as a function of a switch-on state of the additional heater. The parameter associated with the activity of the additional heating is thus the switch-on state ("on" or "off" or the like) of the additional heating. The switch-on state can therefore be regarded as an operating parameter of the additional heater. Thus, an improvement in the efficiency can be achieved with particularly simple means. In particular, the expansion device of a compressor heat pump can be switched over between a first operating position, which corresponds to an off additional heater, and a second operating position, which corresponds to an activated additional heater. Alternatively or additionally, in the case of a compressor heat pump, a flow cross section between a smallest flow cross section of the expansion device can be switched over in the case of an activated additional heater and a largest flow cross section in the case of an activated additional heater. In particular, the expansion device only needs to have these two operating positions. Alternatively, e.g. the speed of a compressor motor of a compressor heat pump between a first speed, which corresponds to an off additional heater, and a second speed, which corresponds to an activated auxiliary heater, are switched.

It is still a preferred embodiment that the heat pump, in particular their performance, in dependence on a temperature difference and / or a pressure difference is adjustable or regulated. The associated with the activity of the additional heating at least one parameter thus includes a temperature difference and / or a pressure difference. The temperature difference and / or a pressure difference may be a difference in the air duct or the process air. The temperature difference and / or the pressure difference may alternatively or additionally be a difference in the refrigeration cycle or the refrigerant. This embodiment allows a particularly accurate adaptation of the heat pump.

It is particularly preferred that the heat pump, in particular its output, be adjustable in dependence on a temperature difference and / or a pressure difference across the evaporator (i.e., between an inlet temperature and an outlet temperature of the refrigerant at the evaporator).

The setting of the heat pump, in particular its power, depending on the actual heating power, the temperature difference, the pressure difference and / or another parameter of the exhaust air dryer, which may take several values, may be proportional (ie, linearly proportional or non-linearly proportional ) are set to this parameter, if necessary only within a predetermined value range of the parameter.

The adjustment or regulation can be carried out alternatively or additionally with reaching or exceeding / falling below one or more threshold values of at least one parameter of the exhaust air laundry drying device. Thus, a speed of a compressor motor may be increased or decreased stepwise or continuously, if corresponding threshold values of the heating power and / or the temperature difference at the evaporator are reached.

The object is also achieved by a method for operating an exhaust air dryer with an auxiliary heater and a heat pump, wherein the method comprises at least the following steps: (a) monitoring at least one associated with an activity of the additional heating parameter (eg a power of the additional heating and or a temperature difference on an evaporator) and (b) controlling the heat pump as a function of the at least one parameter. The method has the same advantages as the described exhaust air dryer and can be configured in an analogous manner.

In particular, monitoring can include determining a desired value and / or measuring an actual value.

For example, in step (b), controlling the heat pump may include controlling a speed of a compressor motor of a compressor heat pump.

Also, step (a) may be configured as: (a) monitoring a turn-on state (on / off) of the booster heater.

In the context of another example, step (a) may comprise: (a) monitoring a temperature difference and / or a pressure difference (in particular of the coolant, in particular between an inlet temperature and an outlet temperature of the coolant at the evaporator).

In the following, the invention will be described in more detail by means of exemplary embodiments, which are schematically illustrated in the figures of the attached drawing. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity. Show it:

1 shows a sketch of an exhaust air dryer according to a first embodiment;

2 shows a sketch of an exhaust air-drying machine according to a second embodiment; and

3 shows a sketch of an exhaust air dryer according to a third embodiment.

1 shows a sketch of an exhaust air dryer 1 according to a first embodiment. The exhaust air dryer 1 is a front loader with a rotating laundry drum 2 as a laundry treatment room. From an outside space A, an air intake passage leads 3 to the laundry drum 2 , At the air inlet duct 3 is a fan 4 for conveying air L (then still as fresh air) from the outside space A into the laundry drum 2 and further (as exhaust air) from the laundry drum 2 via an air outlet duct 5 again in the outer space A. When flowing through the laundry drum 2 The air L absorbs moisture of laundry W contained therein to dry the laundry W.

For heating the air L in the air intake duct 3 in an energy-saving way, the exhaust air dryer shows 1 a compression heat pump 8th to 11 with an evaporator 8th , a condenser or condenser 9 , a compressor or compressor 10 and a relaxation device in the form of an expansion valve 11 on. The condenser 9 is with the air intake duct 3 thermally coupled, and the evaporator 8th is with the air outlet duct 5 thermally coupled. This will cause the air outlet duct 5 or in the air outlet duct 5 located warm humid air (exhaust air) L heat withdrawn and put on the evaporator 8th transfer. Conversely, the fact that the liquefier 9 with the air inlet duct 3 is thermally coupled, heat from the condenser 9 on the air intake duct 3 or on the in the air intake duct 3 be transferred air (fresh air) L transferred. By the temperatures or temperature differences on the evaporator 8th and the liquefier 9 is the heat pump 8th to 11 operated. An operation of the heat pump 8th to 11 is basically well known and need not be further elaborated here.

At the air inlet duct 3 is also an additional heater 7 arranged to heat the laundry W even more and to accelerate their drying. The fan 4 may alternatively at the air outlet duct 5 be arranged.

An efficiency of the heat pump 8th to 11 depends on these temperatures or temperature differences and can by a design, for example by dimensioning the elements of the heat pump 8th to 11 be optimized for given boundary conditions. In order to keep the efficiency high for changing boundary conditions, especially in an operation of the exhaust air dryer 1 optionally with and without additional heating 7 , is a speed of the compressor 10 or its compressor motor 15 adjustable or adjustable. The compressor motor 15 is in particular a BLDC motor, which ensures its stepless controllability, if so desired. To monitor the speed like the compressor motor 15 a speed sensor (o.Fig.) Have or be coupled to such.

To set or regulate the speed in the heat pump or refrigeration cycle of the heat pump 8th to 11 in front of and behind the evaporator 8th temperature sensor 12 and 13 provided, which an inlet temperature and an outlet temperature of the coolant to the evaporator 8th of sensing. The temperature sensors 12 and 13 are with a serving as an evaluation device control device 14 coupled, as indicated by the associated dashed lines. The control device 14 For example, the operation of other components (such as the laundry drum 2 and the additional heating 7 ) Taxes. In the control device 14 are those of the temperature sensors 12 and 13 sensed sensor signals or temperature values linked to a temperature difference.

The control device 14 So monitors the temperature difference and can the speed of the compressor motor 15 set continuously depending on the temperature difference, eg proportional to the temperature difference. In particular, the speed may be reduced with increasing temperature difference and increased with decreasing temperature difference. In addition, the speed may assume a minimum (but finite) value, if the temperature difference when the auxiliary heater is switched off 7 reaches or falls below a lower threshold. By adjusting the speed, the heat pump 8th to 11 with high accuracy to the operation of the exhaust air dryer 1 with and without additional heating 7 adapted, even if a power of additional heating 7 is variable.

In addition, also like a property of the expansion valve 11 how its flow cross-section, be adjustable or adjustable.

2 shows a sketch of an exhaust air dryer 21 according to a second embodiment. The exhaust air dryer 21 is similar to the exhaust air dryer 1 trained, except that now the speed of the compressor motor 15 depending on a current heating capacity of the additional heater 7 is adjustable. The current heating power can be measured by means of a current sensor 22 be measured or otherwise, eg indirectly, recorded or calculated.

3 shows a sketch of an exhaust air dryer 31 according to a third embodiment. The exhaust air dryer 21 is similar to the exhaust air dryer 21 trained, but now the speed of the compressor motor 15 only as a function of a (in particular gradually variable) setpoint of the heating power of the additional heater 7 be set. Here, on an associated sensors, eg 22 be omitted because the setpoint (in the present example, as an absolute value or as a relative value (eg as a heating level)) is already known and eg in the control device 14 can be stored.

Of course, the present invention is not limited to the embodiments shown.

Thus, features of various embodiments may be additionally or alternatively used.

LIST OF REFERENCE NUMBERS

1

 Exhaust laundry drying device

2

 washing drum

3

 Air inlet duct

4

 fan

5

 air outlet

7

 additional heating

8th

 Evaporator

9

 condenser

10

 compressor

11

 expansion valve

12

 temperature sensor

13

 temperature sensor

14

 control device

15

 compressor motor

21

 Exhaust laundry drying device

22

 current sensor

31

 Exhaust laundry drying device

A

 outer space

L

 air

W

 Laundry

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19737075 A1 [0002]
• DE 102007062776 A1 [0004]
• US 2010/0077787 A1 [0005]
• DE 102007016077 A1 [0006]

Claims (10)

Exhaust Air Dryer ( 1 ; 21 ; 31 ), comprising - an air intake duct ( 3 ), which from the outside (A) to a heatable laundry treatment room (A) ( 2 ), - an air outlet duct ( 5 ) coming from the laundry treatment room ( 2 ) leads to the outside (A), - a heat recovery unit for transferring heat from the air outlet duct ( 5 ) on the air inlet duct ( 3 ) and - one at the air inlet duct ( 3 ) arranged additional heating ( 7 ), where - the heat recovery unit is a controllable heat pump ( 8th to 11 ). Exhaust Air Dryer ( 1 ; 21 ; 31 ) according to claim 1, wherein the heat pump ( 8th to 11 ) a drive ( 10 ), which generates a higher thermal power than the auxiliary heater ( 7 ). Exhaust Air Dryer ( 21 ) according to one of the preceding claims, wherein a sum of the thermal outputs of the heat pump ( 8th to 11 ) and the additional heating ( 7 ) can be higher than a maximum permissible electrical connection power. Exhaust Air Dryer ( 1 ; 21 ; 31 ) according to claim 3, wherein a maximum allowable electrical connection power is between 2 kW and 2.5 kW. Exhaust Air Dryer ( 1 ; 21 ; 31 ) according to one of the preceding claims, wherein the heat pump ( 8th to 11 ) an evaporator ( 8th ), a liquefier ( 9 ), a drive in the form of a compressor ( 10 ) and a relaxation device ( 11 ) and wherein the liquefier ( 9 ) with the air inlet duct ( 3 ) is thermally coupled and the evaporator ( 8th ) with the air outlet duct ( 5 ) is thermally coupled. Exhaust Air Dryer ( 1 ; 21 ; 31 ) according to claim 5, wherein the compressor ( 10 ) a variable speed compressor ( 10 ). Exhaust Air Dryer ( 1 ; 21 ; 31 ) according to one of claims 5 or 6, wherein the evaporator ( 8th ) in the air outlet duct ( 5 ) is arranged. The exhaust air drying apparatus according to any one of claims 1 to 4, wherein the heat pump is a gas process heat pump. Exhaust Air Dryer ( 1 ; 21 ; 31 ) according to one of the preceding claims, wherein the exhaust air drying device ( 21 ) has at least one first mode and a second mode, wherein - in the first mode, the heat pump ( 8th to 11 ) and the additional heating ( 7 ) are operated at maximum power and - in the second operating mode, only the heat pump ( 8th to 11 ) is operated. Exhaust Air Dryer ( 1 ; 21 ; 31 ) according to one of the preceding claims, wherein the heat pump ( 8th to 11 ) depending on at least one with an auxiliary heating activity ( 7 ) is controllable.

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