EP2674527A1

EP2674527A1 - Laundry treatment apparatus with heat exchanger unit

Info

Publication number: EP2674527A1
Application number: EP12171660.9A
Authority: EP
Inventors: Paolo Ros; Alessandro Vian
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2012-06-12
Filing date: 2012-06-12
Publication date: 2013-12-18
Also published as: WO2013186129A1

Abstract

The invention relates to a laundry treatment apparatus, in particular dryer or washing machine having drying function, wherein the apparatus comprises: a laundry treatment chamber for treating laundry using process air, a process air loop for circulating the process air, and a heat exchanger unit (2) arranged in the process air loop comprising a first heat exchanger (4) having a plurality of first fins (6) adapted to cool the process air and a second heat exchanger (8) having a plurality of second fins (10) adapted to heat the process air, wherein the first heat exchanger (4) and the second heat exchanger (8) are separated by a gap (16) such that the first fins (6) and the second fins (10) are separated from each other by the gap (16), wherein the heat exchanger unit (2) is arranged in a basement of the treatment apparatus, wherein the first heat exchanger (4) and the second heat exchanger (8) are connected to each other by means of at least two connecting plates (12, 14), and wherein at least one of the connecting plates (12, 14) extends across or essentially extends across the side surfaces of the first heat exchanger (4) and the second heat exchanger (8) and over the gap (16) between the first fins (6) and second fins (10).

Description

The invention relates to a laundry treatment apparatus, in particular a dryer or a washing machine having dryer function, comprising a heat exchanger unit.
In the heat pump tumble dryer of EP 2 034 084 A1 the heat pump system is arranged in a basement of the dryer. An evaporator, condenser, auxiliary condenser and compressor are provided as separate elements such that they have to be separately assembled at the time of manufacturing.
It is an object of the invention to provide a cost-efficient laundry treatment apparatus comprising a robust heat exchanger unit.
The invention is defined in claim 1. Particular embodiments are set out in the dependent claims.
According to claim 1 a laundry treatment apparatus comprises a laundry treatment chamber for treating laundry using process air, a process air loop for circulating the process air and a heat exchanger unit arranged in the process air loop, wherein the heat exchanger unit is located in a basement of the treatment apparatus. The heat exchanger unit comprises a first heat exchanger having a plurality of first fins which are adapted to cool the process air and a second heat exchanger having a plurality of second fins which are adapted to heat the process air. The first and second heat exchangers are separated by a gap or spacing, such that the first fins and the second fins are separated from each other by the gap. The first and second fins are spaced apart such that they do not physically contact each other. The gap or spacing between the first and second heat exchanger may be non-linear, e.g. meandering or labyrinth formed when seen from above or when seen from a direction perpendicular to the process air flow through the heat exchanger unit and parallel to the fins (which are preferably plate-shaped and/or flat).
The first heat exchanger and the second heat exchanger are connected to each other by means of at least two connecting plates, wherein at least one of the connecting plates extends across or essentially extends across the side surfaces of the first heat exchanger and the second heat exchanger and over the gap between the first and second fins. I.e. the at least one connecting plate extends across or essentially extends across the side surface of the heat exchanger unit. In an embodiment one or two of these cross-extending connecting plates are provided or both of the two connecting plates are such cross-extending connecting plates. The at least one connecting plate extends or essentially extends across the (entire) side surface of the heat exchanger unit providing a larger connecting area (e.g. more connecting points) and therefore a strong and reliable connection between the first and second heat exchanger. Thus the heat exchanger unit is robust and easy to handle, e.g. during assembly or maintenance of the apparatus, as a risk of damage of the heat exchanger unit during handling due to the robust build-up is prevented. The unit consisting of first and second heat exchangers connected by the at least one connecting plate is preferably provided as pre-assembled unit such that at the time of final dryer assembling the number of assembling steps and parts to be assembled is significantly reduced.
The gap or spacing provided by the gap between the first and the second heat exchanger may be in longitudinal or flow direction of the heat exchanger unit and/or the gap between respective first fins and second fins may be in longitudinal or flow direction of the heat exchanger unit. In particular a gap or spacing is not provided in the at least one connecting plate.
Preferably the treatment apparatus comprises a heat pump system having a refrigerant loop and a compressor for circulating a refrigerant through the refrigerant loop, wherein the heat exchanger unit is part of the heat pump system and the first and second heat exchangers are included in the refrigerant loop for passing the refrigerant there through. For example the first heat exchanger may be an evaporator or refrigerant (gas) heater for heating the refrigerant and cooling process gas and the second heat exchanger may be a condenser or refrigerant (gas) cooler for cooling the refrigerant and heating process gas, i.e. process air.
The connecting plates may be arranged on opposing sides of the heat exchanger unit and additionally or alternatively on adjacent sides of the heat exchanger unit. For example connecting plates may be arranged on each lateral side of the heat exchanger unit, i.e. the sides of the heat exchanger unit parallel or essentially parallel to the process air flow. E.g. one or more of the connecting plates may extend across or may essentially extend across the side surface of the heat exchanger unit. E.g. the heat exchangers are connected to each other by two connecting plates extending or essentially extending across the (entire) side surface of the heat exchangers and the gap, which provides an even stronger and more robust connection between heat exchangers.
Connecting plates which extend across or essentially across the (entire or three or all four) side surfaces of the first and second heat exchanger and the gap may be provided on each lateral side of the heat exchanger unit. I.e. the connecting plates laterally surround the heat exchanger unit forming a portion of the process air channel, whereby the process air flow is efficiently guided through the heat exchanger unit. In this embodiment a bottom and/or lower connecting plate may be provided with a condensate channel for conveying condensate generated at the evaporator away from the heat exchanger unit. Alternatively a lower connecting plate is omitted or does not extend across the entire lower surface of the heat exchanger unit, in particular not across the lower surface of the evaporator.
Preferred the at least one connecting plate extends or the connecting plates extend as a single piece over the or essentially over the entire lateral side surfaces of the first and second heat exchangers to provide a simple and cost-efficient connection.
The at least one connecting plate may have heat conducting capability. For example the at least one connecting plate is formed of metal having heat conductivity such that it assists in exchanging heat between the process air and the refrigerant guided through (e.g. refrigerant pipes of) the first and/or second heat exchanger. Alternatively the at least one connecting plate is formed of a thermally non-conducting material. In this case heat conduction between the first and second heat exchanger via solid state contact conduction is avoided or reduced. For example the at least one connecting plate may be formed from plastic, resin, ceramic, glass or any other material having low heat conductivity as compared to metal (e.g. compared to iron, aluminum or copper).
Preferably the at least one connecting plate is formed of a material and/or has material properties different to the ones of the first and/or second fins (of the first and second heat exchanger, respectively). Preferably the different material or material property renders the at least one connecting plate mechanically more stable as if made from the material of the fins. Preferably the at least one connecting plate has a thickness at least 1.5, 2, or 3 fold the thickness of the first and/or second fins. Additionally or alternatively the at least one connecting plate has reinforcement ribs and/or edges extending perpendicular or essentially perpendicular to the base plate of the connecting plate for providing mechanical rigidity. Preferably the at least one connecting plate has an alignment structure and additionally or alternatively one or more alignment elements adapted to align the heat exchanger unit in a process air channel, a battery channel and/or in the basement of the treatment apparatus, such that assembly of the treatment apparatus is facilitated. For example the alignment structure and/or the alignment elements effect the heat exchanger unit to be centered within the process air channel and/or battery channel, such that the fins are optimally aligned with respect to the process air flow. In particular the process air channel and/or battery channel may be at least partially arranged in the basement or lower part of the apparatus.
Preferred the connecting plate is or the connecting plates are parallel or essentially parallel to a longitudinal or flow direction of the heat exchanger unit. Alternatively or additionally the connecting plate is or the connecting plates are parallel or essentially parallel to first and/or second fins. Thus the connecting plate(s) efficiently guide or convey the process air through the heat exchanger unit, in particular across the gap between the heat exchangers.
According to an embodiment the basement of the apparatus comprises a bottom shell and a cover shell to form a portion of the process air loop and/or to form the process air channel and/or battery channel where the heat exchanger unit is arranged. I.e. the basement of the apparatus is formed by at least two parts which are easy and fast and therefore cost-efficient to assemble.
Preferably at least one connecting plate forms at least a portion of a wall of the bottom shell, of the cover shell and/or of the battery channel. I.e. the at least one connecting plate forms a structural part of the basement of the treatment apparatus, in particular a portion of a process air channel.
According to an embodiment at least one connecting plate is fixed to or is integrally or monolithically formed at the bottom shell or the cover shell. I.e. the bottom shell or cover shell is part of heat exchanger unit, whereby the heat exchanger unit is reliably attached to the basement by connection to the at least one connecting plate.
The inlet and outlet (connections and/or openings) for guiding refrigerant to and from the heat exchanger unit may be arranged on one side of the heat exchanger unit. Thus the inlet and outlet are easily and conveniently accessible during assembly or maintenance of the treatment apparatus.
Preferably a refrigerant pipe for guiding refrigerant along a portion of the refrigerant loop is passing through the at least one connecting plate. Alternatively one or more turning loops of the refrigerant pipe are passing through the at least one connecting plate. Thus the refrigerant pipe efficiently forms a connection between the heat exchanger and the at least one connecting plate.
According to an embodiment the first and the second heat exchanger have a common row pitch in longitudinal or flow direction of the heat exchanger unit, wherein the gap or spacing between the first and the second heat exchanger is a multiple of the row pitch. I.e. the row pitch of the refrigerant pipes of the first and second heat exchanger are the same, whereby the preparation of the at least one connecting plate is simplified as the same pitch for holes or apertures for the refrigerant pipes are provided for the entire connecting plate. In particular the refrigerant pipe diameter is the same for the first and second heat exchanger. The preparation is further simplified, as the 'pitch' of the gap or spacing is a multiple of the common row pitch. The pitch multiple being for example in the range of 1.5 to 10, 2 to 8 or 3 to 5.
Preferably the basement comprises a bottom shell over which at least a portion of the heat exchanger unit or at least the first heat exchanger is arranged, wherein the bottom shell comprises a condensate channel which extends along, in parallel and/or below at least one of the connecting plates. E.g. the at least one connecting plate forms an outer side of the heat exchanger unit and the condensate channel extending along, parallel and/or below the connection plate such as to efficiently collect condensate at least from the entire first heat exchanger and also to collet condensate which might be generated at the at least one connecting plate.
The at least one connecting plate may at least partially have the function of a fin common for the first and the second heat exchanger. For example at least one connecting plate is formed by a common outer or external fin of the first and the second heat exchanger, wherein such common fin may be designed as described above (e.g. higher mechanical rigidity).
According to an embodiment the first and second fins of the first and second heat exchanger, respectively, are arranged such that at least one or more first fins at least partially overlap with at least one or more second fins. E.g. the fins are interlocking but without contact between first and second fins, i.e. the fins are spaced apart, such that a gap or spacing is provided between the first fins and second fins. In particular the first fins overlap the second fins or vice versa when seen in side projection perpendicular to fin surface. Thus the overlapping fins guide the process air flow in the gap or spacing between the first and second heat exchanger. I.e. the overlapping fins prevent cross-flow of process air. Further with the same outer dimension of the heat exchanger unit, the overlapping fins provide a larger heat exchange surface, i.e. fin surface, whereby the heat exchanger unit operates more efficient.
Reference is made in detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying figures, which show:

Fig. 1: a perspective view of a heat exchanger unit,
Fig. 2: a perspective view of the heat exchanger unit of Fig. 1 and a bottom shell of a treatment apparatus before assembly, and
Fig. 3: a perspective view of the heat exchanger unit and the bottom shell of Fig. 2 after assembly.

Fig. 1 shows a perspective view of a heat exchanger unit 2 for a laundry treatment apparatus like a heat pump tumble dryer. The heat exchanger unit 2 comprises an evaporator 4 having a plurality of evaporator fins 6, a condenser 8 having a plurality of condenser fins 10 and a first and second connecting plate 12, 14 arranged on opposing lateral sides of the heat exchanger unit 2. The connecting plates 12, 14 connect the evaporator 4 to the condenser 8 with a gap 16 or spacing between them, such that the heat exchanger unit 2 is formed. A plurality of refrigerant pipe loops 18a-d of the condenser 8 and the evaporator 4 extend through the connecting plates 12, 14, such that the evaporator 4 and condenser 8 are connected to the connecting plates 12, 14 and therefore connected to each other.
The evaporator 4 is adapted to heat a refrigerant flowing through the refrigerant pipe (loops) 18a and to cool process gas or process air B (Fig. 3) passing through the evaporator 4. The condenser 8 is adapted to cool refrigerant flowing through refrigerant pipe (loops) 18b and to heat process gas or air. Process air B flows longitudinally through the heat exchanger unit 2, in particular parallel or essentially parallel to a fin alignment A of the fins 6, 10 of the evaporator 4 and condenser 8 or parallel or essentially parallel to the connecting plates 12, 14. I.e. the heat exchanger unit is configured such that process air B enters the heat exchanger unit 2 via a lateral front face 28, passes the evaporator 4, where it is cooled down, passes the gap 16 and the condenser 8, where the process air A is heated, and leaves the condenser 8 via a rear face 30 of the heat exchanger unit 2 to be reintroduced to a drying compartment (not shown) of a treatment apparatus (only bottom part 1 thereof is shown in Figs. 2 and 3).
Refrigerant inlets 20a-b and refrigerant outlets 22a-b of the evaporator 4 and condenser 8 extend through the first connecting plate 12. I.e. all refrigerant connections are located on the same side of the heat exchanger unit 2, thus facilitating the connection to refrigerant feed and drain pipes 24a-b, 26a-b (Fig. 2).
The basement 1 or base unit of the treatment apparatus comprises two (shell or body) parts, a bottom shell 34 and a cover shell (not shown), whereby the assembly of the basement or the base unit is facilitated. Fig. 2 shows a perspective view of the heat exchanger 2 of Fig. 1 and the bottom shell 34 of a treatment apparatus before assembly. The bottom shell 34 (together with the cover shell) forms part of a process air loop of the treatment apparatus, in particular a front channel 44 in front of the heat exchanger unit 2, a battery channel 38 (adapted to receive the heat exchanger unit 2 therein) and a rear channel 46 behind or downstream the heat exchanger unit 2. A condensate channel 36 is provided which is located below the evaporator 4 after assembly of the heat exchanger unit 2 and the bottom shell 34 (Fig. 3). Condensate generated at the evaporator 4 during a drying operation of the treatment apparatus is collected and conveyed via the condensate channel 36 towards a drain outlet (not shown).
A compressor 42 is mounted on the bottom shell 34 with refrigerant feed pipes 24a-b and drain pipes 26a-b connected thereto to feed and drain refrigerant to and from the evaporator 4 and condenser 8. When the heat exchanger unit 2 is connected to the refrigerant pipes 24a-b, 26a-b, a closed refrigerant loop is provided through which the refrigerant is circulated by the compressor 42.
The heat exchanger unit 2, i.e. each connecting plate 12, 14, comprises alignment elements 32a-d protruding from the connecting plates 12, 14. The bottom shell 34 comprises corresponding receiving elements 40a-b at the front side and the rear side of the heat exchanger unit 2 for receiving and therefore aligning the heat exchanger unit 2 with respect to the bottom shell 34 and the battery channel 38, respectively.
Fig. 3 shows a perspective view of the heat exchanger unit 2 mounted in the bottom shell 34 of the basement 1 - the elements of Fig. 2 after assembly. For clarity the compressor 42 and refrigerant pipes 24a-b, 26a-b have been omitted. The heat exchanger unit 2 is received and aligned in the bottom shell 34, i.e. in the battery channel 38, in its operating position. Process air B from the front channel 44 enters the heat exchanger unit 2 via its front face 28, passes the heat exchanger unit 2 parallel or essentially parallel to the fin alignment A, i.e. along the fins 6, 10, where the process air is cooled at the evaporator 4 to remove moisture and heated at the condenser 6 to be returned to the drying compartment. The process air B exits the heat exchanger unit 2 via the rear face 30 and is guided by the rear channel 46 to a drying compartment of the treatment apparatus.

Reference Numeral List

1: bottom portion or basement of laundry treatment apparatus
2: heat exchanger unit
4: evaporator
6: evaporator fins
8: condenser
10: condenser fins
12: first connecting plate
14: second connecting plate
16: gap
18a-d: refrigerant pipe loop
20a-b: refrigerant inlet
22a-b: refrigerant outlet
24a-b: refrigerant feed pipe
26a-b: refrigerant drain pipe
28: front face
30: rear face
32a-d: alignment element
34: bottom shell
36: condensate channel
38: battery channel
40a-b: receiving element
42: compressor
44: front channel
46: rear channel

A: fin alignment
B: process air flow

Claims

Laundry treatment apparatus, in particular dryer or washing machine having drying function, comprising:
a laundry treatment chamber for treating laundry using process air,

a process air loop for circulating the process air, and

a heat exchanger unit (2) arranged in the process air loop comprising a first heat exchanger (4) having a plurality of first fins (6) adapted to cool the process air and a second heat exchanger (8) having a plurality of second fins (10) adapted to heat the process air,

wherein the first heat exchanger (4) and the second heat exchanger (8) are separated by a gap (16) such that the first fins (6) and the second fins (10) are separated from each other by the gap (16), and

wherein the heat exchanger unit (2) is arranged in a basement of the treatment apparatus,

characterized in that

the first heat exchanger (4) and the second heat exchanger (8) are connected to each other by means of at least two connecting plates (12, 14), wherein at least one of the connecting plates (12, 14) extends across or essentially extends across the side surfaces of the first heat exchanger (4) and the second heat exchanger (8) and over the gap (16) between the first fins (6) and second fins (10).
Apparatus according to claim 1, comprising a heat pump system having a refrigerant loop and a compressor (42) for circulating the refrigerant through the refrigerant loop, wherein the heat exchanger unit (2) is part of the heat pump system and the first and second heat exchanger (4, 8) are included in the refrigerant loop for passing the refrigerant there through.
Apparatus according to claim 1 or 2, wherein a first connecting plate (12) extends across or essentially across one side surface and a second connecting plate (14) extends across or essentially extends across an opposing side surface of the first heat exchanger (4) and the second heat exchanger (8).
Apparatus according to claim 1, 2 or 3, wherein the at least one connecting plate (12, 14) extends as a single piece over the or essentially over the entire lateral side surfaces of the first and second heat exchanger (4, 8).
Apparatus according to any of the previous claims, wherein the at least one connecting plate (12, 14)
is formed of a material or has a material structure that is mechanically more stable than one of the first or second fins (6, 10),
has a thickness at least 1.5, 2, or 3 fold the thickness of the first or second fins (6, 10), or
has reinforcement ribs or edges extending perpendicular or essentially perpendicular to the base plate of the connecting plate (12, 14) for providing mechanical rigidity.
Apparatus according to any of the previous claims, wherein the at least one connecting plate (12, 14) has an alignment structure or one or more alignment elements (32a-d) adapted to align the heat exchanger unit (2) in an process air channel, a battery channel (38) or in the basement of the treatment apparatus.
Apparatus according to any of the previous claims,
wherein the connecting plate is or the connecting plates (12, 14) are parallel or essentially parallel to a longitudinal or flow direction of the heat exchanger unit (2), or
wherein the connecting plate is or the connecting plates (12, 14) are parallel or essentially parallel to fins (6, 10) of the first and the second heat exchanger.
Apparatus according to any of the previous claims, wherein the basement of the apparatus comprises a bottom shell (34) and a cover shell to form a portion of the process air loop or to form a battery channel (38) where the heat exchanger unit (2) is arranged.
Apparatus according to any of the previous claims, wherein inlets (20a-b) and outlets (22a-b) for guiding the refrigerant to and from the heat exchanger unit (2) are arranged on one side of the heat exchanger unit (2).
Apparatus according to any of the previous claims, wherein a refrigerant pipe for guiding refrigerant along a portion of the refrigerant loop is passing through the at least one connecting plate (12, 14), or wherein one or more turning loops (18a-c) of the refrigerant pipe are passing through the at least one connecting plate (12, 14).
Apparatus according to any of the previous claims, wherein the first and the second heat exchanger (4, 8) have a common row pitch in longitudinal or flow direction of the heat exchanger unit (2), and wherein the gap (16) or spacing between the first and the second heat exchanger (4, 8) is a multiple of the row pitch.
Apparatus according to any of the previous claims, wherein the basement comprises a bottom shell (34) over which at least a portion of the heat exchanger unit (2) or at least the first heat exchanger (4) is arranged, wherein the bottom shell (34) comprises a condensate channel (36) which extends along, in parallel or below at least one of the connecting plates (12, 14).