Patent Description:
A dual ventilation system aims at extracting exhaust air from one or more rooms, for example from a house or a building, and blowing fresh air into said rooms to renew and thus purify the air of the rooms. The dual ventilation system comprises a fresh air circuit and an exhaust air circuit.

The dual ventilation system also comprises a thermal exchanger disposed at a junction between the exhaust and fresh air circuits to heat up the fresh air blown into the rooms with the exhaust air extracted from the room. This thermal exchanger is used when the temperature of the outside fresh would interfere with the comfort of the users.

A dual ventilation system comprises a dual flow ventilation unit having a casing connected to both fresh and exhaust air circuits to form a junction between these two circuits within the casing. A thermal exchanger is disposed within the casing at this junction.

Condensation may occur on the walls of the thermal exchanger when fresh or exhaust air contains water vapor. These condensates have to be evacuated from the casing to ensure the working of the ventilation system.

To evacuate these condensates, dual flow ventilation units generally comprise a drainage tray disposed inside the casing and below the thermal exchanger to collect these condensates by gravity. A drainage duct is connected to this drainage tray to evacuate these condensates. Due to the collection of the condensates by gravity, the casing must be oriented with the drainage tray disposed at the bottom of the casing.

For the installation of a dual flow ventilation unit in a building, air ducts of the exhaust and fresh air circuits have to be connected to the unit, one inlet and one outlet for each air circuit. These air ducts may be already positioned such that the connection of the dual flow ventilation unit to the fresh and exhaust air circuits may be difficult because the orientation of the casing is already set with the drainage tray disposed at the bottom of the casing.

Some existing dual flow ventilation unit may include the possibility to readdress the air inlets and outlets of the unit to make it correspond to the actual position of the preinstalled air ducts. However, the unit must be adapted to this swap, notably by reprogramming the controller of the unit for proper operation of the unit. This swap is therefore very constraining for the installer and requires advanced knowledge.

<CIT> discloses a ventilation unit upon which the preamble of claim <NUM> is based.

There is a need for an improved dual flow ventilation unit allowing a more flexible installation, particularly for the connection to fresh and exhaust air circuits.

To solve this problem, the invention provides a dual-flow ventilation unit for extracting exhaust air from at least one room and blowing fresh air into said at least one room, said dual-flow ventilation unit having a casing comprising two main walls opposite each other and a plurality of lateral walls extending between said two main walls, said casing comprising:.

characterized in that each of said main walls comprises a receiving slot configured to receive said drainage collector so that said drainage collector is configured to be selectively fixed to either one of said main walls depending on the orientation of the casing.

Providing each of the main walls, i.e. each opposite side of the casing, with a receiving slot associated with a removable drainage collector allows to fix the removable collector to either of the two opposite main walls. The casing may be thus disposed in at least two orientations: a first orientation wherein a first main wall is facing downwards and a second position wherein a second main wall opposite to the first one is facing downwards. In other words, the orientation of the casing may be reversed to lean on either of the main walls while ensuring that the condensate generated onto the thermal exchanger may be collected into the drainage collector by gravity.

This ability to reverse the orientation of the casing onto either of the main walls improve the number of connecting configurations of the casing to the fresh and exhaust air circuits. The installation of the dual flow ventilation unit is therefore made more flexible.

According to an embodiment of the dual flow ventilation unit, said drainage collector is a cover forming at least a part of an external surface of the casing when received into said receiving slot.

According to an embodiment of the dual flow ventilation unit, each of said receiving slots forms a through-hole facing said thermal exchanger in a direction perpendicular to said main walls, said drainage collector being disposed within said through-hole when received into said receiving slot, said through-hole having dimensions allowing the thermal exchanger to be removed through said through-hole.

According to an embodiment of the dual flow ventilation unit, said drainage collector comprises a water retention cavity extending below the thermal exchanger when the casing is oriented with drainage collector facing downwards, the drainage collector further comprising a drainage duct extending along the main wall onto which the drainage collector is fixed and is in fluid communication with the water retention cavity to conduct water near a lateral wall of the casing.

According to an embodiment of the dual flow ventilation unit, each of said main walls comprises a duct imprint to receive said drainage duct when said drainage collector is received within said receiving slot, said duct imprint extending from a central portion of the main wall towards a lateral wall of the casing.

According to an embodiment of the dual flow ventilation unit, said drainage collector comprises an internal surface in contact with said thermal exchanger to form an abutment for said thermal exchanger when said drainage collector is received within said receiving slot.

According to an embodiment of the dual flow ventilation unit, said drainage collector comprises air and water tightness means between said internal surface of the drainage collector and said thermal exchanger.

According to an embodiment of the dual flow ventilation unit, said drainage collector comprises air tightness means extending around the thermal exchanger when said drainage collector is received within the receiving slot.

According to an embodiment of the dual flow ventilation unit, said thermal exchanger comprises a fresh air entrance opening and a fresh air exit opening as well as an exhaust air entrance opening and an exhaust exit opening, said water retention cavity at least extending below the exhaust air exit opening of the thermal exchanger when the drainage collector is fixed to either one of said main walls.

According to an embodiment of the dual flow ventilation unit, at least one lateral wall of the casing comprising an additional drainage collector for collecting by gravity water generated by condensation on the thermal exchanger and conducting said water outside the casing.

According to an embodiment of the dual flow ventilation unit, said additional drainage collector is formed by a drainage through-hole within a lateral wall facing exhaust air exit opening of the thermal exchanger to allow water generated by condensation onto the thermal exchanger to flow by gravity through said drainage through-hole.

According to an embodiment of the dual flow ventilation unit, the drainage collector is configured to be secured to said receiving slot with one or more among: a screwing connection, a snap-fit connection or a close fit connection.

The invention also provides a method for installing a dual-flow ventilation unit according to any one of the preceding claims in a building comprising an exhaust air circuit and a fresh air circuit, comprising the steps of:.

According to an embodiment of the installing method, the drainage collector is already fixed to a main wall before the fixing step, said method comprising a step of removing the drainage collector from said main wall before the fixing step.

In the description which follows, the drawing figures are not necessarily to scale and certain features may be shown in generalized or schematic form in the interest of clarity and conciseness or for informational purposes. In addition, although making and using various embodiments are discussed in detail below, it should be appreciated that as described herein are provided many inventive concepts that may embodied in a wide variety of contexts. Embodiments discussed herein are merely representative and do not limit the scope of the invention which is defined by the appending claims.

It will also be obvious to one skilled in the art that all the technical features that are defined relative to a process can be transposed, individually or in combination, to a device and conversely, all the technical features relative to a device can be transposed, individually or in combination, to a process.

The terms "comprise" (and any grammatical variation thereof, such as "comprises" and "comprising"), "have" (and any grammatical variation thereof, such as "has" and "having"), "contain" (and any grammatical variation thereof, such as "contains" and "containing"), and "include" (and any grammatical variation thereof such as "includes" and "including") are open-ended linking verbs. They are used to specify the presence of stated features, integers, steps or components or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps or components or groups thereof. As a result, a method, or a step in a method, that "comprises", "has", "contains", or "includes" one or more steps or elements possesses those one or more steps or elements but is not limited to possessing only those one or more steps or elements.

The present invention provides a dual flow ventilation unit of a dual flow ventilation system according to claim1.

A dual flow ventilation system comprises an exhaust air circuit for extracting exhaust air from one or more rooms and a fresh air circuit for blowing fresh air to said one or more rooms. Each of said fresh and exhaust air circuits comprises an air duct extending from said one or more rooms to an outside area.

The fresh air and exhaust air circuits correspond to a first and a second air circuits.

As shown on <FIG>, the dual flow ventilation unit <NUM> comprises a casing <NUM> having a first <NUM> and a second <NUM> main walls facing each other and disposed at opposite sides of the casing. The casing <NUM> further comprises a plurality of lateral walls <NUM> extending between the first <NUM> and the second <NUM> main walls. The casing <NUM> defines an internal cavity <NUM> delimited by the first <NUM> and second <NUM> main walls as well as the lateral walls <NUM>.

The casing <NUM> has three dimensions in space: a width, a length and a height with the length and the width perpendicular to the height. The casing <NUM> is substantially parallelepipedal with the main walls defining the length and the width and the lateral walls defining the height of the parallelepiped. Particularly, the casing <NUM> is preferably a perpendicular parallelepiped. The height of the casing <NUM> is preferably lower than each of the length and width so that the casing is essentially a flat parallelepiped.

In the preferred embodiment shown on <FIG>, vertices of the parallelepiped formed by the casing are truncated when observed in a direction A perpendicular to the first <NUM> or the second <NUM> main walls. Hence, four sloping lateral walls <NUM> are formed at each vertex of the casing <NUM> when observed in said direction A perpendicular to the first <NUM> or the second <NUM> main walls.

The casing <NUM> comprises a fresh air inlet <NUM> and a fresh air outlet <NUM> in fluid communication with each other along a fresh air channel <NUM>. The fresh air inlet <NUM> and outlet <NUM> are respectively configured to be connected to a first <NUM> and a second <NUM> air ducts of a fresh air circuit <NUM>.

The casing <NUM> also comprises an exhaust air inlet <NUM> and an exhaust air outlet <NUM> in fluid communication with each other along an exhaust channel <NUM>. The exhaust air inlet <NUM> and outlet <NUM> are respectively configured to be connected to a first <NUM> and a second <NUM> air ducts of an exhaust air circuit <NUM>.

The fresh air inlet <NUM> and outlet <NUM> and the exhaust air inlet <NUM> and outlet <NUM> are formed on a lateral wall <NUM> so that the fresh air <NUM> and exhaust air <NUM> channels substantially extend perpendicularly to the direction A.

The fresh air inlet <NUM> and outlet <NUM> and the exhaust air inlet <NUM> and outlet <NUM> are disposed around the casing <NUM> such that the fresh air <NUM> and exhaust air <NUM> channels intersect at a central portion of the casing <NUM>. This central portion is for example centered around the direction A. In this configuration, the fresh air <NUM> and exhaust air <NUM> channels extend to form an X, each end of the X corresponding to one of the fresh air inlet <NUM> and outlet <NUM> and the exhaust air inlet <NUM> and outlet <NUM>.

In the preferred embodiment wherein the vertices of the casing <NUM> are truncated, each of the fresh air inlet <NUM> and outlet <NUM> and the exhaust air inlet <NUM> and outlet <NUM> is disposed at a sloping lateral wall <NUM>.

As shown on <FIG>, the casing <NUM> further comprises a thermal exchanger <NUM> disposed at the junction of the fresh <NUM> and exhaust <NUM> air channels. The thermal exchanger <NUM> is particularly disposed at the central portion of the casing <NUM>. The thermal exchanger <NUM> and the fresh and exhaust air channels are disposed within said internal cavity <NUM> of the casing <NUM>.

The thermal exchanger <NUM> comprises a fresh air entrance opening <NUM> and a fresh air exit opening <NUM> as well as an exhaust air entrance opening <NUM> and an exhaust exit opening <NUM>. The fresh air channel <NUM> passes through the fresh air entrance opening <NUM> and the fresh air exit opening <NUM>. The exhaust air channel <NUM> passes through the exhaust air entrance opening <NUM> and the exhaust exit opening <NUM>.

The thermal exchanger <NUM> allows heat transfer between the exhaust air and the fresh air without mixing it. The thermal exchanger is for example a plate heat exchanger.

The dual flow ventilation unit <NUM> may further comprise an additional heating device <NUM> disposed in the fresh air channel <NUM>. The additional heating device <NUM> is for example disposed between the fresh air inlet <NUM> and the fresh air entrance opening <NUM>.

The dual flow ventilation unit <NUM> may also comprise a bypass device <NUM> allowing the exhaust air to bypass the thermal exchanger <NUM>. The bypass device <NUM> comprises a movable flap <NUM> directing the exhaust air either through the thermal exchanger <NUM> or through a bypass channel <NUM> which is in fluid communication with the exhaust air outlet <NUM>. Hence, the exhaust air does not flow through the thermal exchanger <NUM> when the thermal exchanger is bypassed. This bypass functionality allows not to heat the fresh air blown into the one or more rooms with the thermal exchanger <NUM> if the temperature inside said rooms is considered to be sufficient. It is particularly useful when the dual ventilation system is operated in summer.

The bypass channel <NUM> is preferably running along a peripheral portion of the casing <NUM>, between one of the first <NUM> or second <NUM> main walls and the fresh air channel <NUM>. The bypass channel <NUM> is distinct from and thus not in fluid communication with the fresh air channel <NUM>.

The dual flow ventilation unit <NUM> comprises ventilating means for moving air through said fresh air <NUM> and exhaust air <NUM> channels. Ventilating means are preferably air fans disposed within said fresh air <NUM> and exhaust air <NUM> channels. In the embodiment shown on <FIG>, a first air fan (not shown) is disposed between the exhaust air outlet <NUM> and the exhaust air exit opening <NUM>. A second air fan (not shown) is disposed between the fresh air outlet <NUM> and the fresh air exit opening <NUM>.

The dual flow ventilation unit <NUM> comprises a drainage collector <NUM> for collecting by gravity water generated by condensation on the thermal exchanger <NUM> as well as conducting said water outside the casing <NUM>. The drainage collector <NUM> is disposed below the thermal exchanger <NUM> to be able to collect water by gravity.

The drainage collector <NUM> is removably fixed to one of said first <NUM> and second <NUM> main walls. Particularly, as shown on <FIG>, each of said first <NUM> and second <NUM> form a receiving slot <NUM> configured to receive said drainage collector <NUM>. Hence, each of the first <NUM> and second <NUM> main walls is configured to receive said drainage collector <NUM> so that said drainage collector <NUM> is selectively fixed to either one of said first <NUM> and second <NUM> main walls depending on the desired orientation of the casing <NUM>.

The drainage collector <NUM> is for example screwed to either the first <NUM> or the second <NUM> main walls.

Providing each of the first <NUM> and second <NUM> main walls, i.e. each opposite side of the casing <NUM>, with the receiving slot <NUM> associated with a removable drainage collector <NUM> allows to fix the removable drainage collector <NUM> to either of the two opposite first <NUM> and second <NUM> main walls. The casing <NUM> may be thus disposed in at least two orientations: a first orientation wherein the first main wall <NUM> is facing downwards and a second position wherein a second main wall <NUM> opposite to the first one is facing downwards. In other words, the orientation of the casing <NUM> may be reversed to lean on either of the main walls while ensuring that the condensates generated onto the thermal exchanger <NUM> may be collected into the drainage collector <NUM> by gravity.

In these first and second orientations of the casing, the direction A extends vertically to allow water collection by gravity using the drainage collector <NUM>.

This ability to reverse the orientation of the casing <NUM> onto either of the first <NUM> and second <NUM> main walls improves the number of connecting configurations of the casing to the fresh <NUM> and exhaust <NUM> air circuits. The installation of the dual flow ventilation unit <NUM> is therefore made more flexible.

As shown on <FIG>, <FIG> and <FIG>, the drainage collector <NUM> comprises a water retention cavity <NUM> formed to extend below the thermal exchanger when the casing is oriented with drainage collector facing downwards. Particularly, the water retention cavity <NUM> may be formed to encompass at least two openings among the fresh air entrance <NUM> and exit <NUM> openings and the exhaust air entrance <NUM> and exit <NUM> openings when observed along the direction A. Most particularly, the water retention cavity <NUM> may be formed to encompass at least the fresh air exit opening <NUM> and the exhaust air exit opening <NUM> when observed along the direction A so that condensates generated onto said fresh air <NUM> and exhaust air <NUM> exit openings can be collected by gravity.

The water retention cavity <NUM> may also comprise water guide <NUM> which allows to prevent water from leaving the water retention cavity <NUM>. In other words, the water guide <NUM> allows preventing water leakage. This water guide <NUM> comprises a ramp part extending perpendicularly from an internal surface <NUM> of the drainage collector <NUM> and a cover part extending from the ramp part along the internal surface <NUM>. Hence, the water guide <NUM> has a L-shaped cross-section extending at partially around the water retention cavity <NUM>. the water guide <NUM> preferably extends from a bottom part <NUM> of the water retention cavity <NUM> to near an exit orifice <NUM> intended to be in fluid communication with a drainage duct <NUM>. The shape of the water guide <NUM> allows to guide water through the exit orifice <NUM> while preventing this water to leak inside the casing <NUM>.

The drainage collector <NUM> may comprise two water retention cavities <NUM> disposed at opposite sides of the drainage collector <NUM>. Each of these water retention cavities <NUM> is intended to be in fluid communication with a drainage duct <NUM>. In doing so, the water drainage may operate whatever the side of the casing <NUM> orientated downwards. Each water retention cavity <NUM> may comprise a water guide <NUM> as described above.

The drainage collector <NUM> may further comprise a drainage duct <NUM> extending perpendicular to the direction A and in fluid communication with the water retention cavity <NUM> to allow condensates to evacuate the casing <NUM>. The drainage duct <NUM> extends in a plane perpendicular to the direction A.

Each of said first <NUM> and second <NUM> main walls may comprise a duct imprint <NUM> to receive said drainage duct <NUM> when said drainage collector <NUM> is received within the receiving slot <NUM>. The duct imprint <NUM> extends from the central portion of the casing <NUM> towards a lateral wall of the casing <NUM>. The drainage duct <NUM> is preferably removably fixed to a collector body <NUM> of the drainage collector <NUM>. The drainage duct <NUM> may be fixed to the duct imprint by friction.

In a preferred embodiment shown on <FIG>, <FIG>, the drainage collector <NUM> is a cover forming at least a part of an external surface of the casing when received into said receiving slot <NUM>. In other words, the drainage collector <NUM> is at least partly in the form of a plate removably fixed to either the first <NUM> or the second <NUM> main walls.

Each receiving slot of the first <NUM> or the second <NUM> main walls forms a through-hole <NUM> intended to face said thermal exchanger <NUM> in the direction A. The drainage collector <NUM> is disposed within said through-hole <NUM> when received into said receiving slot <NUM>. In other words, the through-hole <NUM> is covered by the drainage collector <NUM>.

Said through-hole <NUM> preferably has dimensions allowing the thermal exchanger <NUM> to be removed through said through-hole <NUM>. In other words, an edge <NUM> defining the outline of the through-hole <NUM> extends beyond the outline of the thermal exchanger <NUM> when observed along the direction A. It allows to ease extraction of the thermal exchanger <NUM>, for example for the maintenance or replacement of the thermal exchanger <NUM>.

The drainage collector <NUM> comprises an internal surface <NUM> in contact with said thermal exchanger <NUM> to form an abutment for said thermal exchanger <NUM> when said drainage collector <NUM> is received within said receiving slot <NUM>. This abutment is formed along the direction A, i.e. in a direction perpendicular to the first <NUM> and second <NUM> main walls. As shown on <FIG>, the drainage collector <NUM> comprises air and water tightness means between said internal surface of the drainage collector <NUM> and said thermal exchanger <NUM>. The air and water tightness means are for example in the form of a seal plate <NUM> intended to abut against the thermal exchanger <NUM> when said drainage collector <NUM> is received within said receiving slot <NUM>.

The air and water tightness means allow to provide an air and water seal between the thermal exchanger <NUM> and the drainage collector <NUM>. Furthermore, the air and water tightness means, e.g. the seal plate <NUM>, also provide thermal insulation and noise reduction. The air and water means may be made with foam. The air and water tightness means preferably obturate the through-hole <NUM> when the drainage collector <NUM> is received within the receiving slot <NUM> to improve thermal insulation and noise reduction.

The drainage collector further comprises air tightness means between the collector body <NUM> and the first <NUM> or the second <NUM> main walls. Said air tightness means extend around the through-hole <NUM> when said drainage collector <NUM> is received within the receiving slot <NUM>. Said air tightness means are for example a sealing strip <NUM>. Said airtightness means extend around the water retention cavity <NUM>.

Said dual flow ventilation unit <NUM> comprises an additional drainage collector <NUM> providing at a lateral wall <NUM> of the casing <NUM>. This additional drainage collector <NUM> is configured to collect by gravity water generated by condensation on the thermal exchanger <NUM> and conduct said water outside the casing <NUM> when the casing <NUM> is in a third orientation where the direction A is horizontal. The additional drainage collector <NUM> allows to change the orientation of the direction A such that the installation of the casing <NUM> is further flexible.

As shown on <FIG>, the additional drainage collector <NUM> is preferably formed by a drainage through-hole <NUM> within a lateral wall <NUM> facing the fresh air <NUM> and exhaust air <NUM> exit openings of the thermal exchanger <NUM> to allow water generated by condensation onto the thermal exchanger <NUM> to flow by gravity through said drainage through-hole <NUM>.

The dual flow ventilation unit <NUM> further comprise a covering plate (not shown) intended to be fixed to one of the receiving slot <NUM> of the first <NUM> or second <NUM> main walls, particularly the main wall onto which the drainage collector is not fixed to. Hence, the covering plate allows to close the through-hole <NUM> of the receiving slot <NUM> when the drainage collector <NUM> is fixed to the other main wall. The covering plate is also configured to contact the thermal exchanger <NUM> when disposed within the receiving slot <NUM>. This covering plate also comprises air and water tightness means to provide an air and water seal between the thermal exchanger <NUM> and the covering plate as well as between the covering plate and the receiving slot <NUM>. These air and water tightness means may comprise a seal plate <NUM> dimensioned to both contact the thermal exchanger <NUM> when the covering plate is fixed to the receiving slot <NUM> and contact the receiving slot <NUM>.

The drainage collector <NUM> may comprises two cut-out portions <NUM> configured to each face an air filter <NUM> disposed through the fresh air <NUM> and exhaust air <NUM> channels. These cut-out portions <NUM> allows to remove these air filters <NUM> without removing one of the first <NUM> and second <NUM> main walls or the drainage collector <NUM>. Said cut-out portions <NUM> are dimensioned and positioned so that an air filter <NUM> can be removed from the casing <NUM> through the corresponding cut-out portion <NUM> without removing the drainage collector <NUM>. The maintenance of the air filters <NUM> is thus facilitated. One air filter is preferably disposed between the fresh air inlet <NUM> and the fresh air entrance opening <NUM> of the thermal exchanger <NUM>. Another air filter is preferably disposed between the exhaust air inlet <NUM> and the exhaust air entrance opening48 of the thermal exchanger <NUM>.

A method for is also provided for installing the dual-flow ventilation unit <NUM> in a local or a building comprising an exhaust air circuit <NUM> and a fresh air circuit <NUM>. Said method comprises a step of determining the position of the exhaust <NUM> and fresh air <NUM> circuits. Particularly, the position of the first <NUM> and second <NUM> air ducts of the fresh air circuit <NUM> and the first <NUM> and second <NUM> air ducts of the exhaust air circuit <NUM>.

Then, the orientation of the casing <NUM> is determined depending on the position of the exhaust <NUM> and fresh <NUM> air circuits. Particularly, the orientation of the casing <NUM> is determined among the first orientation, wherein the first main wall <NUM> is facing downwards, the second orientation, wherein the second main wall <NUM> is facing downwards, and the third orientation wherein the lateral wall <NUM> comprising the additional drainage collector <NUM> is facing downwards.

The orientation is preferably determined so that all or as many inlets and outlets of the casing as possible can be easily connected to the air ducts of the exhaust <NUM> and fresh <NUM> air circuits. For example, if the first air duct <NUM> of the fresh air circuit <NUM> is short or not sufficiently accessible, the installer may choose an orientation of the casing <NUM> allowing to bring the fresh air inlet <NUM> closer to said first air duct <NUM>. In other example, the installer may determine that the space available in the local where the casing <NUM> is installed requires that the casing <NUM> is installed vertically, i.e. with the direction A extending horizontally.

The casing <NUM> may further comprise fastening means to fasten the casing to a support or a wall. In the first and second orientation, the casing <NUM> may lie onto the floor and in the third orientation the casing <NUM> may be fixed to a wall.

Claim 1:
Dual-flow ventilation unit (<NUM>) for extracting exhaust air from at least one room and blowing fresh air into said at least one room, said dual-flow ventilation unit (<NUM>) having a casing (<NUM>) comprising two main walls (<NUM>, <NUM>) opposite each other and a plurality of lateral walls (<NUM>, <NUM>) extending between said two main walls, said casing comprising:
- a thermal exchanger (<NUM>),
- a first (<NUM>) and a second (<NUM>) flow circuits extending at least partially through the thermal exchanger (<NUM>) to transfer heat from air flowing through one of said first (<NUM>) and second (<NUM>) flow circuits to air flowing through the other one among said first (<NUM>) and second (<NUM>) flow circuits, each of the first (<NUM>) and second (<NUM>) flow circuits comprising an air inlet and an air outlet formed through one lateral wall (<NUM>) among the plurality of lateral walls (<NUM>, <NUM>),
- ventilating means for moving air through said first and second flow circuits,
- a drainage collector (<NUM>) for collecting by gravity water generated by condensation on the thermal exchanger (<NUM>) and conducting said water outside the casing (<NUM>), said drainage collector (<NUM>) being removably fixed to one among said main walls (<NUM>, <NUM>),
characterized in that each of said main walls (<NUM>, <NUM>) comprises a receiving slot (<NUM>) configured to receive said drainage collector (<NUM>) so that said drainage collector (<NUM>) is configured to be selectively fixed to either one of said main walls (<NUM>, <NUM>) depending on the orientation of the casing (<NUM>).