EP2549007B1

EP2549007B1 - Heat pump laundry treatment apparatus

Info

Publication number: EP2549007B1
Application number: EP11174963.6A
Authority: EP
Inventors: Alberto Bison; Francesco Cavarretta; Flavio Noviello
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2011-07-22
Filing date: 2011-07-22
Publication date: 2020-02-26
Anticipated expiration: 2031-07-22
Also published as: EP2549007A1

Description

The invention relates to a laundry treatment apparatus having a heat pump system, in particular a dryer, a washing machine or a washer-dryer.
DE 44 09 607 A1 suggests a laundry dryer using a heat pump system with a closed process air loop and a refrigerant loop. In the refrigerant loop a compressor drives the refrigerant through a condenser, an expansion valve, an evaporator and back to the inlet of the compressor. Near the inlet and outlet of the condenser, radiator rips are arranged at the refrigerant pipe. Cooling air is blown by a blower to the radiator rips for cooling the refrigerant and removing excess heat from the heat pump system.
In the heat-pump tumble dryer of EP 1 811 077 A1 the laundry is stored in a rotatable drum and process air is circulated by a fan through the drum, an evaporator and a condenser along a process air guiding path. The refrigerant in the heat pump system is pumped by a high capability two-stage compressor which is located within the process air channel between the evaporator and the condenser. In an embodiment the two-stage compressor is arranged outside the process air channel and in this case the compressor is thermally insulated by an external insulation space. The two pumping stages of the compressor provide a primary and secondary compression of the refrigerant. Between the first and second compression stages a refrigerant pipe is guided to the outside of the compressor and the process air channel. The refrigerant is provided with two valves which can be opened and closed under the control of a control unit such that the refrigerant coming from the first compression stage is feed back to the second compression stage or is guided through an external heat exchanger before it is feed back to the second compression stage. The external heat exchanger is arranged outside the process air channel and in a further embodiment cooling air is blown by a cooling fan to the external heat exchanger. During a warm-up phase the refrigerant is conveyed directly from the first to the second compression stage. After warm-up the closing/opening state of the valves is changed such that the refrigerant is cooled by the external heat exchanger between the first and second compression stage. The external heat exchanger serves for preserving the high pumping capability of the two-stage compressor as soon as the refrigerant is hot and would defer the pumping efficiency if not cooled by the external heat exchanger.
It is an object of the invention to provide a laundry treatment apparatus in which the operation stability and/or efficiency is improved.
The invention is defined in claim 1. Particular embodiments are set out in the dependent claims.
According to claim 1, a laundry treatment apparatus is provided in which the laundry to be treated can be stored in a laundry storing chamber, which is preferably a rotatably supported drum. The laundry is treated by process air, which is preferably completely or at least for the most part of it circulated in a closed processing air loop.
Further features are defined in claim 1.
The laundry treatment apparatus has a heat pump system for dehumidifying and heating the process air. Dehumidifying is made by cooling the process air at a first heat exchanger of the heat pump system (e.g. an evaporator or refrigerant gas heater). Heating is made at a second heat exchanger of the laundry treatment apparatus (e.g. a condenser or refrigerant gas cooler). First and second heat exchangers are serially connected in a refrigerant loop in which the refrigerant is driven by a compressor and expanded by a refrigerant expansion device.
After the warm-up phase of the heat pump system, the excessive heat is removed by an auxiliary heat exchanger (e.g. auxiliary condenser or gas cooler). According to an alternative embodiment of the present invention, the auxiliary heat exchanger is connected in the refrigerant loop serially upstream (with respect to the refrigerant flow) the second heat exchanger. The auxiliary heat exchanger is adapted to transfer heat from the refrigerant to cooling and/or ambient air ('cooling air' in the following). Additionally depositing the heat in liquid may be provided, for example in water stored in the apparatus (e.g. washing water when the apparatus is a washer-dryer). A cooling air blower is assigned to the auxiliary heat exchanger for blowing or sucking cooling air through the auxiliary heat exchanger.
According to the invention a shielding device is arranged such that the compressor is shielded against the cooling air blown by the blower. In an embodiment the compressor is additionally shielded by providing an compressor insulation adapted to prevent heat exchange between the compressor and the compressor's outer ambient. With the insulation heat exchange between the compressor and the air surrounding the compressor and the cooling air moved by the cooling air blower is prevented or essentially prevented. By thus preventing the compressor's outer surface being cooled by cooling air the operation temperature of the compressor is independent from the influence by the cooling air. For example the compressor's ambient or outer wall temperature is independent from the cooling air being driven by the cooling air blower or not, the cooling air temperature, the spatial cooling effect on the compressor's outer case and/or the cooling air flow rate. Hence the operation temperature of the compressor is independent of the cooling air characteristics and variations which results in an improved uniformity of the compressor operation temperature over time is achieved. This in turn improves its operation efficiency and long-life cycle.
With the shielding/insulation, the excessive heat amount is removed from the refrigerant without increasing the compressor heat losses. Therefore the temperature level of the refrigerant and of the process air is kept quite constant while the temperature of the compressor is kept under safety level without penalizing the performances of the system.
Preferably the maximum cooling capacity of the combination auxiliary heat exchanger and cooling air flow rate driven by the blower is in the range of the heating capacity (heat power) deposited by the compressor in the heat pump system. In the heat pump system the heating power (i.e. at the second heat exchanger) is higher than the cooling power (i.e. at the first heat exchanger) according the following: P(second heat exchanger) = P(first heat exchanger)+ P(power compressor) - P(power loss) where power loss is the amount of power lost and transferred to the environment. As in the steady state the net power deposited in and removed from the process air loop is zero, which means P(first heat exchanger) = P(second heat exchanger), the auxiliary heat exchanger needs a cooling capacity of about P(auxiliary heat exchanger) = P(power compressor) - P(power loss). As under normal conditions heat is dissipated from the process air loop and the refrigerant loop through other channels (e.g. heat loss through laundry storing chamber walls), the cooling capacity of the auxiliary heat exchanger (P(auxiliary heat exchanger)) is in the range of 10 to 100%, 15 to 80%, 20 to 60% of the P(power compressor).
Preferably the shielding device is arranged between the compressor and the auxiliary heat exchanger and/or the cooling air blower. Relating to the cooling air flow path the blower may be arranged between the shielding device and the auxiliary heat exchanger or the auxiliary heat exchanger is arranged between the shielding device and the blower. In embodiments the blower blows or sucks the cooling air through the auxiliary heat exchanger.
In an embodiment the shielding device may be formed by, may be partially formed by or is a partition wall, a component housing and/or a process air duct section. For example a section of the process air duct is arranged between blower and auxiliary heat exchanger on the one side and the compressor on the other side of the duct section. Or a drive motor housing and/or a power electronics housing is arranged to shield the compressor. Or a separate partition wall is provided to shield the compressor. The shielding device may be formed at a bottom shell of the apparatus, preferably as an integral or monolithic part therewith (e.g. in a mold process with the bottom shell), and/or the shielding device additionally has a guiding function for guiding the cooling air from or to a housing opening to exhaust or inhale the cooling air at a predetermined opening in the apparatus housing, in particular a predetermined opening at the bottom wall, a side wall and/or a bottom shell of the apparatus cabinet. The air flow guiding or deflection function of the shielding device is used for example to deflect the air flow direction with respect to the cooling air flow direction which is given by the geometry of the cooling air blower and/or the auxiliary heat exchanger. The shielding device having deflection function gives more freedom in the design and integration of the auxiliary heat exchanger/cooling air blower in the spatial layout of the apparatus.
In addition to shield the cooling air flow in a potential path to the compressor, it is advantageous to provide the shielding device with one or more side shields each at a respective side of the auxiliary heat exchanger (i.e. on one or more sides thereof). The side shield(s) extend partially or fully along a lateral side of the auxiliary heat exchanger and provide(s) additional channeling of the cooling air flow to improve efficiency in cooling of the auxiliary heat exchanger and shielding the compressor.
In a preferred embodiment at least a portion of the cooling air flow is guided to another component of the apparatus, for example to power electronics of the apparatus, like a power converter for the compressor and/or the drum driving motor, and/or to a motor of the apparatus, like the drum drive motor. If only a portion of the cooling air flow is to be used to cool such other components, preferably an auxiliary or branching cooling air guiding channel is used to guide the airflow to such other component(s). In an embodiment the auxiliary or branching cooling air channel has an input or an outlet at the shielding surface of the shielding device.
Preferably the main components of the heat pump system (at least the first and second heat exchangers and the compressor) are arranged in a base section of the apparatus and a section of a process air channel is arranged in a middle region of the base section. Preferably this section of the process air channel houses the first and second heat exchanger, wherein this arrangement is sometimes called the 'battery' of the heat pump system. In an embodiment the compressor is arranged at one side of the middle process air channel section and the auxiliary heat exchanger and the cooling air blower are arranged at another side of the middle channel section opposite to the compressor. In this way the middle channel section forms the shielding device shielding cooling air from being blown towards or being sucked from the compressor. Alternatively the cooling air blower and the auxiliary heat exchanger are arranged at a height level above the first and second heat exchanger, for example above the battery or the cooling air channel in which the first and second heat exchanger are arranged. In this case again the cooling air flow path is offset to the compressor location and cooling of the compressor is prevented.
Preferably for achieving the cooling power to remove the excessive heat during the steady state (see above) the auxiliary heat exchanger has a cooling power in the range from 10 to 500 W, 50 to 450 W or 100 to 450 W, and/or the auxiliary heat exchanger is adapted to reduce the refrigerant temperature by 2 to 18°C, 5 to 15°C, 8 to 13°C or 10 to 15°C. Additionally or alternatively the maximum conveyance capacity of the cooling air blower is in the range of 10 to 180 m³/h, 20 to 100 m³/h, or 40 to 80 m³/h.
In an embodiment the operation of the laundry treatment apparatus is controlled by control unit, including the operation and monitoring of the heat pump system. Preferably the control unit is adapted to activate the cooling air blower after the warm-up phase or when approaching the steady state. End of the warm-up phase or arriving or approaching the steady state is for example detected by a sensor device detecting the temperature and/or pressure of the refrigerant (or being dependent on the refrigerant) at a predefined location of the refrigerant loop, for example at or close to the first heat exchanger inlet or outlet. Preferably the control unit is adapted to keep the blower operating during the steady state until the running laundry treatment process is finished.
In an embodiment the conveyance or flow rate or rotation speed of the cooling air blower may be varied around a non-zero value without undershooting the zero value so as to keep continuous (positive) operation of the blower. Variation of the conveyance rate of the blower may be required to keep the operation condition of the heat pump system at a predetermined level or within a predetermined target range for optimizing the heat pump system efficiency and/or maintaining the steady state. Adaptation of cooling air flow rate may be required during a treatment cycle, if for example the laundry is to be dried and laundry humidity decreases, or if the cooling air is ambient air having a varying ambient air temperature. Then the control unit can adapt the cooling air flow rate to keep the cooling capacity of the auxiliary heat exchanger at or approximately at the excess heat power deposited by the compressor in the system, i.e. P(auxiliary heat exchanger) = P(power compressor) - P(power loss), within the ranges indicated above.
Reference is made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying figures, which show:

Fig. 1: a schematic view of a tumble dryer with a heat pump system;
Fig. 2: a top view of the basement section of the tumble dryer,
Fig. 3: an enlarged detail view of Fig. 2 in partial cross-section,
Fig. 4: a cross-sectional side view of a detail of the basement section,
Fig. 5: a perspective view of the basement section of Fig. 2,
Fig. 6: the bottom view of the basement section,
Fig. 7: a side view of the basement section partially opened,
Fig. 8: a second embodiment of a basement section of the dryer in simplified top view representation with components placed left and right to the center channel,
Figs. 9 and 10: a third and fourth embodiment of a basement section of the dryer in simplified top view representation with compressor shields in different arrangement,
Fig. 11: a fifth embodiment of a basement section of the dryer in simplified top view representation with heat pump components placed on the top of the heat pump battery, and
Fig. 12: a heat loss diagram for different operation modes of the heat pump system.

Fig. 1 depicts in a schematic representation a home appliance 2 which in this embodiment is a heat pump tumble dryer. The tumble dryer comprises a heat pump system 4, including in a closed refrigerant loop in this order of refrigerant flow B: a first heat exchanger 10 acting as evaporator (gas heater) for evaporating (heating) the refrigerant and cooling process air, a compressor 14, a second heat exchanger 12 acting as condenser (gas cooler) for cooling the refrigerant and heating the process air, an auxiliary heat exchanger 34 acting as additional condenser, and an expansion device 16 from where the refrigerant is returned to the first heat exchanger 10. Together with the refrigerant pipes connecting the components of the heat pump system 4 in series, the heat pump system forms a refrigerant loop 6 through which - in normal operation - the refrigerant is circulated by the compressor 14 as indicated by arrow B. The auxiliary condenser 34 dissipates heat to the ambient of the dryer 2 in the steady state of the heat pump system 4 in which maximum or nearly maximum operation condition is achieved after the warm-up period and the heat deposited by the compressor in the refrigerant loop 6 has to be removed via auxiliary condenser 34 to prevent overheating.
The sequence of the components in the refrigerant loop can be modified in the embodiments herein in that the auxiliary condenser 34 is not placed between the condenser 12 and the expansion device 16 with respect to refrigerant flow, but between the compressor 14 and the condenser 12 (not shown). This modification is applicable to all embodiments herein.
The expansion device 16 is a controllable valve that operates under the control of a control unit to adapt the flow resistance for the refrigerant in dependency of operating states of the heat pump system. In alternative embodiments the expansion device 16 can be a capillary tube, a valve with fixed expansion cross-section, a throttle valve with variable cross section that automatically adapts the expansion cross-section in dependency of the refrigerant pressure (e.g. by elastic or spring biasing), a semi-automatic throttle valve in which the expansion cross-section is adapted in dependency of the temperature of the refrigerant (e.g. by actuation of a thermostat and/or where the temperature of the refrigerant is taken between the gas cooler and the gas heater, the gas heater and the compressor, or the compressor and the gas cooler), or the like.
The process air flow within the home appliance 2 is guided through a compartment 18 of the home appliance 2, i.e. through a compartment 18 for receiving articles to be treated, e.g. a drum 18. The articles to be treated are textiles, laundry 19, clothes, shoes or the like. In the embodiments here these are preferably textiles, laundry or clothes. The process air flow is indicated by arrows A in Fig. 1 and is driven by a process air blower 8. Outside the drum 18 the process air A is guided through an air channel 20. The air exiting the drum 18 through the drum outlet (which is the loading opening of the drum) is filtered by a first fluff filter 22 arranged close to the drum outlet in or at the channel 20. Then the air flows through a second fluff filter 24 arranged close to the first heat exchanger 10, through the first heat exchanger 10, through the second heat exchanger 12 and is guided back through an or a plurality of openings in the backside of drum 18 into the drum. Thus a closed process air loop is formed.
When the heat pump system 4 is operating in the equilibrium or a normal mode (after the warm-up period i.e. after starting the heat pump system 4 from ambient temperature state), the first heat exchanger 10 transfers heat from the process air to the refrigerant. By cooling the process air to lower temperatures, humidity from the process air condenses at the first heat exchanger 10, is collected there and the collected condensate is drained to a condensate collector 30. The process air cooled and dehumidified when passing the first heat exchanger passes then through the second heat exchanger 12 where heat is transferred from the refrigerant to the process air. The process air is sucked from exchanger 12 by the blower 8 and driven into the drum 18 where it heats up the laundry 19 and receives the humidity therefrom.
The main components of the heat pump system 4 are arranged in a base section 5 or basement of the dryer 2, different embodiments of which are shown in the following figures. The process air channel 20 guides the process air flow A outside the drum 18 and includes different sections, including the section forming the battery channel 20a in which the first and second heat exchangers 10, 12 are arranged. The process air exiting the second heat exchanger 12 flows into a rear channel 20b in which the process air blower 8 is arranged. The air conveyed by blower 8 is guided upward in a rising channel 20c to the backside of the drum 18.
In the prior art it is known to blow ambient air for cooling through an auxiliary condenser and then to the compressor or ambient air is blown only to the compressor for cooling. Therein a cooling blower is intermittently switched ON/OFF by a thermostat if the refrigerant exceeds a critical temperature. This intermittent operation results in a cyclic increase and decrease of the operation temperature of the compressor and the refrigerant in the refrigerant loop. The time diagram in Fig. 12 shows by curve D the time behavior of the heat loss factor for a conventional heat pump tumble dryer in which an auxiliary condenser and the compressor are cooled in such an ON/OFF cycle. E shows the respective time behavior for the dryer 2 according to the invention in which the heat pump system 4 is cooled using only or essentially the auxiliary condenser 34 for removing the excessive heat during the steady state after the warm-up period. As soon as the steady state has been achieved or is approached, a cooling air blower 28 is activated and continuously operated during the steady phase without cooling down the compressor 14.
Curves E and D indicate the heat loss factor which is defined as unity (1) minus the ratio between the power given to the fluid by the compressor (P_cooling) and the electric power adsorbed by the compressor (P_compressor). I.e. the shown heat loss factor = 1 - P_cooling/P_compressor. In other words, the heat loss factor is the percentage of the power adsorbed by the compressor that is lost as heat losses. Of course, the lower this value, the better for the system efficiency. From Fig. 12 it is clear that continuous operation of the blower 28 and keeping the compressor at constant temperature is advantageous over the operation mode in prior art heat pump systems.
According to the preferred embodiment of the invention when reaching or approaching the steady state the cooling air blower 28 is activated and continuously operated. Thus the cooling capacity of the auxiliary condenser 34 is fully used (as compared to the conventional intermittent operation) and the cooling capacity of the auxiliary condenser 34 can be reduced.
Due to the improved efficiency as shown by Fig. 12 the energy efficiency is also improved.
Fig. 2 shows a top view of the heat pump system 4 of the dryer 2 arranged in the dryer base section 5. The base section is housing the heat pump system and parts of the process air channel 20 in a bottom shell 40 forming the base frame of the dryer and having the dryer foots (compare Fig. 6). A cover shell 42 is placed over the bottom shell 40, wherein portions of both shells form the battery channel 20a in which the first and second heat exchanger 10, 12 (which form the battery of the heat pump system) are encased. The rear channel 20b and the blower 8 are also encased by bottom and top shell 40, 42. In Fig. 2 the reference numerals partially (e.g. 8, 10 and 12) have been placed at or over section of the top shell 42 where the component covered by the top shell actually can not be seen, but its location is indicated thereby. The motor 9 for driving blower 8 and the drum 18 is also located under the cover shell 42 and in this embodiment is located between blower 8 and compressor 14.
In front of the inlet of the first heat exchanger 10 the second fluff filter 24 is placed in a drawer inserted into the lower part of the process air channel 20. The condensate water that is condensing at the first heat exchanger 10 is collected in a tray formed below the exchanger 10 in the bottom shell 40 and is guided in a condensate channel at the side of the second heat exchanger 12 into the condensate collector 30 formed by a rear section of the bottom shell 40. A level sensor and a condensate pump are arranged at the collector 30 to pump the condensate to a condensate reservoir at the top of the dryer.
The auxiliary condenser 34 is placed in an upright orientation in the bottom shell 40 such that its slender top side is seen in Fig. 2. At the front side of the condenser 34 the cooling air blower 28 is arranged which sucks in ambient air through openings in the bottom shell 40 at the basement front side of the dryer 2. The conveyed cooling air passes through the condenser 34 from the lower side as shown in Fig. 2 and exits at the upper side the condenser 34 which is the rear side of the condenser when seen from front of the dryer. The cooling air exiting the condenser 34 is guided downward by a deflector shield 36 placed immediately behind the condenser, facing its rear or exit side.
Fig. 3 shows in cross-section an enlarged section of the lower right side of Fig. 2 where the auxiliary condenser 34 is placed. The radiator rips of condenser 34 can be seen arranged around the zigzag or meander-shaped refrigerant pipe. As can be seen from the cross-section, there is a gap between the auxiliary condenser 34 and the deflector shield 36 such that the cooling air that has passed the condenser 34 can flow through the gap. Shield 36 has a side shield 37 that is running at both lateral sides partially over the depth of condenser 34 (the depth direction is the cooling air passing direction) and completely over the top side of the condenser. The partial side shield portions 37 can be seen in cross section in Fig. 3 and the top side shield portion 37 can be seen in the top view of Fig. 2. The shield is enclosing the rear side, partial lateral side and top side of condenser 34 and is open towards the front side (condenser air inlet) and bottom side (air outlet).
Fig. 4 is a lateral cross section of a part of the base section 5 in the region of the condenser 34 along a cross section line from the front of the dryer (left side in Fig. 4) towards the rear side of the dryer. Dashed arrow C indicates the cooling or ambient air flow conveyed by blower 28 through the auxiliary condenser 34 and deflected at its backside downward by the deflector shield 36. The air flow C exits the base section 5 through openings 38 formed in the bottom shell 40. The openings 38 can be seen in more detail in the view from below in Fig. 6.
Fig. 5 shows a perspective view to the base section 5 with the cover shell 42, second fluff filter 24 (drawer), blower 8 and motor 9 removed.
In Fig. 7 the lateral side view of the base section 5 is shown completely as compared to Fig. 4. The cover shell 42 is placed in position and over the motor 9 section of cover shell 42 the power converter 44 for the compressor 14 (and/or other power electronics) is mounted. As a modification of the embodiment shown in Figs. 1 to 6 a branching channel 46 is provided as schematically shown in Fig. 7. The branching channel 46 has a cooling air inlet at the deflector shield 36 and an outlet to the housing encasing the power electronics 44. As soon as the blower 28 is activated, a portion of the ambient air that passed the auxiliary condenser 34 is guided to the power electronics 4 for cooling it.
Figs. 8 to 11 show as schematic view the arrangement of heat pump components in the base section 5 in top view according to other embodiments. The same reference numerals for components of the heat pump system 4 operating the same way as the components in Figs. 1 to 7 are used. For simplicity reference is made to the above and deviating implementations are indicated below.
In the embodiment of Fig. 8 in the base section 5 the blower 8, drum and blower motor 9 and compressor 14 are arranged on a first side of the battery channel 20a, and the blower 28, the condenser 34 and the power electronics 44 are arranged on a second side of the battery channel 20a. The battery channel 20a is forming a center or middle section of the base section 5 running from a front region to the back region of the base section 5. It provides a partition wall or deflector shield 36a preventing a cooling or ambient air flow from the cooling air blower 28 to the compressor 14. Optionally the power electronics 44 is not arranged in the flow path of the cooling air. For example the power electronics is arranged above the motor 9 similarly as shown in Fig. 7. The cooling air flow C is sucked in by blower 28 through openings in the front region of the base section 5, is pushed by the blower 28 through the condenser 34 towards power electronics 44, is deflected by the outer case of the condensate collector to the side and exits the base section 5 through openings at a side wall thereof. In further embodiments of Fig. 8 the cooling air flow C is reversed and/or the blower 28 is arranged on the rear side of condenser 34 (when seen from the front of dryer 2).
It is to be noted that in the embodiment of Fig. 8 the depth of the dryer may be decreased as compared to the 60 cm depth of a conventional dryer. For example the depth of such dryer type is maximum or less than 55 cm, 50 cm or 45 cm. By the depth reduction the volume of the drum is reduced at the same time while the drum diameter is full size adapted to the 60 cm width of conventional dryers. With reduced drum volume the required drying capacity is reduced and the dimension or capacity of the components of the heat pump system 4 can be reduced. Thus narrowing the battery channel 20a width as indicated in Fig. 8 is easily implemented. Such dryer is adapted for small apartment use or single/double household needs.
In the embodiment of Fig. 9 the battery channel 20a is arranged on the left side of the base section 5. On the right side of the base section a deflector shield 36b is arranged between the compressor 14 at one side and the condenser 34 and blower 28 at the other side to prevent cooling air flow to the compressor. The blower 28 sucks the cooling air flow C through openings on the left side of the base section and through the auxiliary condenser 34 and blows it against the power electronics 44 and the motor 9. Exhaust of the air flow C is through openings on the lateral side and/or in the bottom of base section 5 (bottom shell 40). Optionally the flow direction of air flow C is reversed and/or the power electronics and/or the motor 9 are not in the cooling air flow path.
In the embodiment of Fig. 10 the housing of motor 9 is arranged between the cooling air flow C and the compressor 14 thus forming a deflector shield 36c. The blower 28 sucks the cooling air through openings in the bottom shell 40 and pushes it through the auxiliary condenser 34 against shield 36c which deflects the flow C through openings in the lateral side of base section 5.
In the embodiment of Fig. 11 the auxiliary condenser 34, blower 28 and power electronics 44 are placed on top and/or above the battery channel 20a (containing evaporator 10 and condenser 12). Optionally the power electronics 44 is not in the flow path of cooling air C and instead e.g. placed on the case of motor 9 (compare Fig. 7). A deflector shield 36d in the form of a cooling air channel wall is provided to guide the air flow C and prevent flowing it towards compressor 14. The air flow enters through openings in the lateral side wall of the - in this case vertically extended - base section (preferably in the bottom shell 40), flows through condenser 44 and is pushed by blower 28 towards the power electronics (optional) and through openings at the backside of the base section. Preferably the cooling air channel 36d covers the lateral side and the top side of the components 34, 28 and 44. In an embodiment the flow direction of air flow C is inverted and/or the channel 36d has openings not at the lateral side wall of the base section, but on the front side of the base section 5.
The cooling air channel 36d preferably is arranged on the outermost left side above the upper level of the battery channel 20a and is preferably small in width as compared to the battery channel 20a. Thereby the lowest point of the drum 18 can be kept close to the upper side of battery channel 20a, while the dead space at the left side within the dryer body is used to arrange the cooling air channel. The same is true in an embodiment in which the cooling air channel is arranged at the outermost right side above the level of the battery channel 20a and/or the case of the motor 9. Compare the position of the power electronics 44 in Fig. 7 - such that the channel 36d takes the position of electronics 44 and preferably does not extend the complete depth of the base section 5, e.g. by providing cooling air inlet or outlet openings at a lateral side or bottom side of the vertically extended base section 5.

In the embodiments the cooling air blower 28 is depicted and arranged as axial blower (axial fan in which the air flow C enters and exits in the axial direction with respect to the blower rotation axis). However in the embodiments a radial blower (radial fan or centrifugal fan) or a tangential blower (cross-flow fan) can be used. If for example a radial blower is used, the backside wall of the radial blower (which is opposite to the inlet opening for the conveyed air) can at the same time represent the deflector shield (shielding device) that prevents air flow to the compressor 14. Preferably if a radial blower is used as blower 28, in the embodiments the cooling air can be sucked through the auxiliary condenser 34 when the radial blower is arranged in the direction of the outlet side of the condenser 34. The cooling air conveyed by the radial blower can then be exhausted into a direction perpendicular to the exit air direction (i.e. preferably the axial inlet direction of the radial blower). For example through openings in the bottom of bottom shell 40. Specifically in the embodiment of Figs. 2 to 7 the order of auxiliary condenser 34 and blower 28 from front to rear can be changed such that the condenser 34 is close to the front opening and the blower is on the backside of condenser 34 and exhausts the cooling air through the outlet openings 38. In this way the radial blower with its housing replaces the axial blower 28 and the deflector shield 36.

Reference Numeral List:

2	tumble dryer	24	second fluff filter
4	heat pump system	28	cooling air blower
5	base section	30	condensate collector
6	refrigerant loop	34	auxiliary condenser
8	process air blower	36, 36a, 36b, 36c, 36d	deflector shield
9	blower + drum motor	36, 36a, 36b, 36c, 36d	deflector shield
10	first heat exchanger (evaporator)	37	side shield
10	first heat exchanger (evaporator)	38	bottom openings
12	second heat exchanger (condenser)	40	bottom shell
12	second heat exchanger (condenser)	42	cover shell
14	compressor	44	power converter
16	expansion device	46	branching channel
18	drum (laundry compartment)
19	laundry	A	process air flow
20	air channel	B	refrigerant flow
20a	battery channel	C	ambient air flow
20b	rear channel	D	conventional heat loss
20c	rising channel	E	reduced heat loss
22	first fluff filter

Claims

Laundry treatment apparatus (2), in particular dryer, washing machine or washing machine having drying function, comprising:
a laundry storing chamber (18) for treating laundry using processing air (A),

a blower (28) for blowing cooling air (C),

a processing air loop for circulating the processing air (A) through the laundry storing chamber (18), and

a heat pump system (4) for dehumidifying and heating the processing air (A), the heat pump system having a refrigerant loop (6), comprising:
a first heat exchanger (10) for heating a refrigerant and cooling the processing air (A),

a second heat exchanger (12) for cooling the refrigerant and heating the processing air (A),

a refrigerant expansion device (16) arranged in the refrigerant loop (6) between the second heat exchanger (12) and the first heat exchanger (10),

a compressor (14) arranged in the refrigerant loop (6) between the first heat exchanger (10) and the second heat exchanger (12),

an auxiliary heat exchanger (34) connected in the refrigerant loop (6) for cooling the refrigerant, wherein the blower (28) is adapted to remove heat from the auxiliary heat exchanger(34); and

a shielding device (36, 36a-d) arranged to shield the compressor (14) against cooling air (C) blown by the blower (28),

characterized in that

the auxiliary heat exchanger (34) is arranged in the refrigerant loop (6):
a) between the second heat exchanger (12) and the refrigerant expansion device (16), or

b) connected in said refrigerant loop (6) with respect to the refrigerant flow serially upstream the second heat exchanger (12) between the compressor (14) and the second heat exchanger (12).
Apparatus according to claim 1, wherein the shielding device (36, 36a-d) is arranged between the compressor (14) and the auxiliary heat exchanger (34) and/or between the compressor (14) and the blower (28),
Apparatus according to claim 1 or 2, wherein the shielding device (36, 36a-d) is or comprises a partition wall, a shell and/or a process air duct section (20a) in which the first and second heat exchangers (10, 12) are arranged.
Apparatus according to claim 1, 2 or 3, wherein the air flow shielding device (36, 36a-d) deflects the cooling air flow (C) and/or wherein the air flow shielding device (36, 36a-d) deflects the cooling air flow (C) to an outlet in the bottom (40) and/or side wall of the apparatus cabinet.
Apparatus according to claim 1, wherein a power electronics (44) of the apparatus is part of the flow shielding device and/or wherein the laundry storing chamber (18) is a rotatable drum and a drum driving motor (9) is part of the flow shielding device (36c).
Apparatus according to any of the previous claims, wherein the auxiliary heat exchanger (34) has a cooling air inlet, a cooling air outlet and a major flow path for the cooling air (C) through the auxiliary heat exchanger, and wherein the air flow shielding device (36, 36b, 36c) shields and/or deflects the cooling air flow away from the direction of the major flow path at the cooling air outlet of the auxiliary heat exchanger.
Apparatus according to any of the previous claims, wherein the air flow shielding device (36, 36a-d) shields the cooling air flow (C) at one, two or three lateral sides (37) of the auxiliary heat exchanger (34), wherein the lateral sides are lateral of the auxiliary heat exchanger with respect to the cooling air outlet or a major flow path of cooling air through the auxiliary heat exchanger.
Apparatus according to any of the previous claims, comprising a cooling air duct (46) to guide at least a portion of the cooling air flow blown by the blower (28) to a power electronics (44) of the apparatus.
Apparatus according to claim 8, wherein the inlet or outlet of the cooling air duct (46) is arranged at the air flow shielding device (36, 36a-d).
Apparatus according to any of the previous claims, wherein the laundry storing chamber (18) is a rotatable drum and the apparatus comprises a motor (9) for driving the drum, wherein the cooling air blown by the blower (28) is blown to the drum driving motor (9) and/or to a power electronics (44).
Apparatus according to any of the previous claims,
wherein the first and second heat exchangers (10, 12) are arranged in a process air duct section (20a) of the processing air loop which is located in a middle section of the base section (5) of the apparatus,
wherein the blower (28) and the auxiliary heat exchanger (34) are arranged at a first side of the middle section, and
wherein the compressor (14) is arranged at a second side of the middle section opposite to the first side.
Apparatus according to claim 11, wherein additionally a drum motor (9) and/or power electronics (44) is arranged at the second side.
Apparatus according to any of claims 1 to 10, wherein the auxiliary heat exchanger (34) and/or the blower (28) are arranged at a height level in the apparatus above the first and second heat exchanger (10, 12).
Apparatus according to any of the previous claims, wherein
the blower (28) is blowing the cooling air (C) towards the auxiliary heat exchanger (34) or is sucking the cooling air from the auxiliary heat exchanger, and/or
the blowing direction of cooling air (C) blown by the blower (28) is perpendicular or parallel to a process air duct section (20a) of the processing air loop in which the first and second heat exchanger (10, 12) are arranged.
Apparatus according to any of the previous claims, wherein
the auxiliary heat exchanger (34) has a cooling power in the range from 100 to 500 W, 150 to 450 W or 200 to 450 W, and/or
the auxiliary heat exchanger (34) is adapted to reduce the refrigerant temperature by 4 to 18°C, 5 to 15°C, 8 to 13°C or 10 to 15°C.
Apparatus according to any of the previous claims, wherein the blower (28) has a conveyance capacity in the range of 30 to 200 m³/h, 50 to 180 m³/h or 100 to 150 m³/h.
Apparatus according to any of the previous claims, wherein the apparatus further comprises a control unit and wherein the control unit is adapted
to control at least one laundry treatment process,
to start the blower (28) as soon as a refrigerant pressure and/or temperature in the refrigerant loop (6) and/or processing air temperature has exceeded or is approaching a predefined value(s), and
to continuously operate the blower (28) throughout the running laundry treatment process.
Apparatus according to claim 17, wherein, after starting the blower (28), the control unit is adapted to operate the blower with a constant speed or with a blower speed that is varied in a range around an average, non-zero speed, wherein the range is less than ± 30%, ± 20% or ± 10% of the average speed.
Apparatus according to any of the previous claims, wherein further the compressor (14) is insulated to prevent heat exchange with the compressor's ambient air and the cooling air (C).