ES2658148T3 - Heat exchanger unit - Google Patents

Abstract

Heat exchanger unit (1) comprising: a housing (2) defining a conduit through which a fluid will flow, a fan (20) disposed in the housing (2) and configured to induce a fluid flow through the conduit in a flow direction (F), a heat exchanger (5) that is V-shaped in side view with a vertex (8) at one end and an opening (12) at the opposite end, being arranged the heat exchanger (5) in the conduit with the opening (12) directed towards the direction of flow (F), in which a line (CL) passing through the vertex (8) of the heat exchanger (5) V-shaped in the side view extends horizontally, in which the fan (20) is arranged downstream of the heat exchanger (5) in the direction of flow (F), characterized in that the heat exchanger (5) it further comprises a connection element (9) that connects an upper heat exchanger part (6) and an int part lower heat exchanger (7), the connecting element (9) being arranged at the vertex (8) and being configured to block the flow of fluid through the heat exchanger (5) at the vertex (8), extending the connecting element (9) beyond the apex (8) of the heat exchanger (5) covering a part of a lower surface of the lower heat exchanger part (7).

Description

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DESCRIPTION

Heat exchanger unit Technical field

The present invention relates to a heat exchanger unit for an air conditioner. In particular, the heat exchanger unit is of a class that can be installed in, for example, hidden behind, a roof of a building or any other location that provides a limited installation space, particularly a limited height.

Frequently, heat exchanger units of this type are also referred to as duct type heat exchanger units, which are connected to and are part of an air duct of an air conditioner.

Background

An example of such a heat exchanger unit is known from EP 2 108 897 A1 which discloses a heat exchanger unit having an L-shaped heat exchanger installed on its side, in which air is flowed through both sections of the "L". Said heat exchanger, however, provides a relatively small heat exchange surface in combination with a relatively uneven distribution of air flowing through the heat exchanger (uneven air distribution). In addition, the height of the heat exchanger unit is relatively large, since the sections of the "L" shaped heat exchanger are arranged with their width oriented vertically.

In EP 2 402 669 A2 a heat exchanger unit is disclosed which provides a larger heat exchange surface and a lower height. This heat exchanger unit implements a V-shaped heat exchanger with a central axis of the "V" oriented horizontally. Therefore, the height of the heat exchanger can be reduced while increasing the heat exchange surface. However, the air distribution of the air flowing through the heat exchanger remains relatively uneven, since the air is blown by a fan towards the apex of the "V" leading to reduced heat exchange efficiency.

From US 5,964,370 A1, a heat exchanger unit having the characteristics defined in the preamble of claim 1 is known.

Brief Description of the Invention

In view of the aforementioned, the object of the present invention is to provide a heat exchanger unit that has been improved with respect to its heat exchange efficiency.

This object is solved by a heat exchanger unit as defined in claim 1. Embodiments of the invention are named in the dependent claims, in the following description and in the accompanying drawings.

According to one aspect, a heat exchange unit is suggested that comprises a housing having a conduit through which a fluid will flow, particularly air (reference is made mainly only to air, but it should be understood that other fluids can also be used). The housing is particularly configured to connect to a fluid path, particularly an air duct, for example, which is connected to a space to be conditioned or a heat source, particularly outside air. As such, the housing will be part of the fluid path.

In addition, a fan is arranged in the housing. Certainly, more than one fan can be provided. In this case, it is desirable that the central shafts of the fans are aligned and located in a horizontal line. The fan or fans are configured to induce a flow of fluid through the conduit in a direction of flow.

In addition, a heat exchanger is provided within the conduit and through which the fluid will flow through the conduit through the fan (s). Preferably, the heat exchanger is arranged in the duct so that air cannot be diverted from the heat exchanger. In other words, the heat exchanger is arranged in the air duct so that the entire amount or at least a greater part of the air flowing through the duct also passes through the heat exchanger. The heat exchanger is V-shaped in a cross-sectional or side view with a vertex at one end and an opening at the opposite end. The angle of the "V" can be adjusted as needed. The larger the angle, the better it will be to achieve uniform air distribution and good efficiency. The smaller the angle, the better it will be to obtain a low height. According to an example, the heat exchanger may comprise two

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planar or plate-shaped heat exchange elements that are positioned to form the "V". These elements can be fluidly connected by coolant pipes through which coolant will flow preferably in parallel. In addition, these elements can be defined as an upper heat exchange element and a lower heat exchange element. The terms "superior" and "inferior" in this context refer to a line that passes through the vertex and extends horizontally in use. In certain embodiments, this line can be a center line or a symmetry line of the heat exchanger when viewed in the side view. In this particular embodiment, the heat exchanger is arranged in the conduit with the opening of the "V" directed towards the direction of flow. In other words, the flow of the fluid through the conduit enters the heat exchanger through the opening of the "V".

In addition, the fan or fans is / are disposed downstream of the heat exchanger in the direction of flow. In other words, the fan is disposed farther from the opening than the apex of the heat exchanger or is disposed on one side of the vertex of the "V" of the heat exchanger.

Since the fan is arranged downstream of the heat exchanger in the flow direction, it can be ensured that the fluid is passing through all or at least most of the heat exchanger in a relatively uniform amount distributed over the heat exchange surface of the heat exchanger (air distribution). In particular, the fan sets a lower pressure on the downstream side of the heat exchanger. Therefore, air is sucked into the duct from a side upstream of the heat exchanger that flows more evenly into a duct inlet opening and therefore into the "V" opening of the heat exchanger. As a result, the amount of air is not concentrated so much in a particular part of the heat exchanger as in the prior art. Therefore, a more uniform air distribution and, therefore, higher efficiency can be achieved.

According to one embodiment, the heat exchanger is symmetrical in the side view. In particular, it is desired that a symmetry line of the heat exchanger be extended horizontally in the side view. In this context, the upper and lower heat exchange elements are preferably identical or at least substantially identical. All these measures help to obtain a uniform air distribution.

In this context, it is also desired that the central axis of the fan or fans, particularly his / her suction opening / s, is located in a line parallel to the line of the V-shaped heat exchanger, particularly its central line or line of symmetry. According to a preferred embodiment, the central axis of the fan or fans, particularly his / her suction opening / s, is located in a common line with the V-shaped heat exchanger line, particularly its line central or line of symmetry in the side view.

According to one aspect, the fan or fans is / are a backward curved centrifugal fan. As described above, the heat exchanger unit is arranged in a fluid path (air duct). The heat exchanger unit is more preferably used as part of a heat source unit (also known as an outdoor unit although it is arranged inside) and can be combined with a compressor or a separate compressor unit to constitute the "unit from outside. " In these devices, a relatively large pressure drop has to be overcome due to barriers and filters. Therefore, a relatively high ESP (external static pressure) is required. In addition, a relatively high air flow is required to allow use in an air conditioner that supplies a plurality of indoor units arranged in the spaces to be conditioned. In this context, normal outdoor units provide an air flow of 120 m3 per minute, while common indoor units provide an air flow of 30 m3 per minute. The apparatus of the heat exchanger unit as described above only requires a lower flow rate compared to normal outdoor units but a higher flow rate compared to conventional indoor units. The use of a backward curved centrifugal fan is desirable to achieve a relatively high ESP and high efficiency air flow. An additional requirement for the heat exchanger unit to be placed on the ceiling is that the entire unit and also the fans have to be restricted in terms of weight and size. In addition, the fluid flow rate must be adjustable. In addition, these requirements can be met by using a backward curved centrifugal fan.

In one embodiment, the flow rate to be induced by the fans is between approximately 60 m3 per minute and 100 m3 per minute and preferably approximately 60 m3 per minute and 85 m3 per minute. This can be obtained efficiently with one or more backward curved centrifugal fans. In addition, the flow rate must also be adjustable at the intervals mentioned above.

The use of a plurality of backward curved centrifugal fans also provides a reduced overall speed of fluid in the high speed areas of the fans. Accordingly, the fans can be located closer to the heat exchanger without attracting the condensation water formed on the outer surface of the heat exchanger into the fans. By placing the fans closest to the heat exchanger, a more compact heat exchanger unit can be achieved in terms of length. In particular embodiments, the vertex must be 20-30 cm away from the fan to prevent water from being sucked into the fan at a flow rate of 85 m3 per minute when using two

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backward curved centrifugal fans. In addition, the use of a plurality of fans leads to less noise since each fan can be driven at lower RPMs to reach a certain air flow rate compared to the use of fewer fans to reach the same air flow rate.

According to the invention, the heat exchanger comprises an air-impermeable connection element that connects an upper and a lower heat exchanger part, for example the upper and lower heat exchanger elements described above. The connecting element is arranged at the vertex and configured to block the flow of fluid through the heat exchanger at the vertex, in particular the tip of the vertex. An area is created at the apex of the heat exchanger, particularly if flat heat exchanger elements are used, which cannot effectively exchange heat. By blocking the flow of fluid through this part by means of the connecting element, the flow in the vertex is decreased. Therefore, the fluid distribution of the fluid flowing through the remaining parts of the heat exchanger is improved. More particularly, the connecting element forms a barrier that creates a higher pressure drop at the vertex causing the reduction of air flow through the vertex. Without the connecting element, the flow of air flowing through the vertex may become too high. In addition, the connecting element can preferably be used to physically connect the upper and lower heat exchanger elements at the apex and, therefore, improve the rigidity of the heat exchanger.

According to the invention, the connecting element extends beyond the apex of the heat exchanger covering a part of a lower surface of the lower part of the heat exchanger, particularly the lower heat exchanger element. In use, condensation water is formed on the outer surface of the heat exchanger that tends to flow along the surfaces of the heat exchanger downwards. Extending the connecting element beyond the vertex so that it covers a part of a lower surface of the lower part of the heat exchanger, this condensation water is guided away from the vertex or front part of the heat exchanger by the extended part of the element of connection. Therefore, water can be prevented from falling down from the heat exchanger at the vertex. If water falls down from the vertex or other parts close to the fan, water can be drawn into the fan and, therefore, into the fluid path (air duct). In the best case, the above configuration guides the water along the lower surface of the lower heat exchanger part towards the very end of the lower heat exchanger part in the heat exchanger opening. As a drain pan will be placed under the heat exchanger (see below) and due to the "V", the distance between the very end of the lower heat exchanger part and the drain pan will be minimal in the length of the heat exchanger and in the drain pan. Therefore, any risk of the water being drawn into the fans and therefore the air duct can be safely prevented.

The use of a V-shaped heat exchanger with the direction of fluid flow to the V-shaped heat exchanger opening can result in a relatively low air flow in the access part of the heat exchanger close to The opening. In order to improve the distribution of fluid through the heat exchanger sections, particularly the upper and lower heat exchanger elements, particularly close to the opening, a guide blade can be provided and positioned between opposite ends in the horizontal direction, that is between the vertex and the opening, of the heat exchanger. According to one aspect, the guide blade is oriented longitudinally between opposite ends, particularly closer to the vertex than to the opening. In one embodiment, the guide blade can be fixed at its ends in the width direction to the housing. According to one embodiment, the guide plate has no physical contact with the heat exchanger, particularly the fins of the heat exchanger. It has been shown that said guide blade is particularly advantageous at higher flow rates that are particularly necessary if the heat exchanger unit of the present invention is used as an outdoor unit (see above), however being located inside. However, the guide plate can also be used for indoor units of air conditioners. Therefore, the guide plate contributes to an increased efficiency of the heat exchanger. Particularly, said guide blade is preferred when the heat exchanger unit is used only in cooling applications of the air conditioner or as an indoor heat exchanger (of an indoor unit) in heat pump applications. Otherwise, there may be a risk that the ice formed on the surface of the upper heat exchanger element oriented towards the guide plate will fall on the guide plate during the defrosting operation and block the flow path through the heat exchanger. hot.

In order to provide a uniform air distribution through the upper and lower heat exchanger part or elements, it is beneficial that the guide blade has an aerodynamic surface with a line of symmetry that is aligned with the line, particularly the line central or the symmetry line of the heat exchanger.

In addition, it has been shown that the guide blade is most effective if the guide blade has a leading edge directed towards the direction of flow and is pointed (sharp). A particularly advantageous form of the guide plate is an aerodynamic surface in the shape of a dolphin fin.

In addition, the effect of the guide blade is as effective as the blade is placed as close as possible to the heat exchanger. However, the effect decreases again when the guide blade is closer to

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15 mm to heat exchanger.

In order to collect condensation water formed on the external surfaces of the heat exchanger, the heat exchanger unit according to one aspect further comprises a drain pan. The drain pan can be a drain pan that needs to be removed or emptied manually or a drain pan that is connected to a drain.

It is preferred that the drain pan has a lower position. If the drain pan is connected to a drain, a drain opening is placed in the lowest position. According to one aspect, it is preferred that the lowest position, and if the drain opening is present, is arranged in that half of the drain pan away from the fan seen in the direction of flow. In particular, the drain pan extends in one direction away from the fan. If the drain pan, in this sense of extension, is separated into halves, the lowest position is in that half that is farther from the fan than the other half. In addition, the drain pan is particularly designed to guide the accumulated water in the drain pan away from the fan to its lowest position and if the drain opening is present. According to a further aspect, the lowest position of the drain pan corresponds to the lower corner (the very end) of the heat exchanger, particularly the lower corner (the very end) of the lower heat exchanger element. Therefore, the drain pan can even be used to support the heat exchanger and it can be ensured that water is guided by the lower heat exchanger element directly to the lowest position of the drain pan (see above).

According to a further aspect, the heat exchanger unit further comprises an insulation (thermal and / or sound) arranged on an opposite side of the heat exchanger with respect to the drain pan. In order to obtain a conduit that is as symmetrical as possible in order to obtain as uniform an air distribution as possible through the heat exchanger, it is preferred that the insulation surfaces and the drain pan directed towards the Heat exchanger have preferably identical approximate shapes. Particularly, in combination with the connection plate, the pressure within the "V" can be balanced with the result of a more uniform fluid flow distribution.

In addition and in order to further prevent water from falling from the heat exchanger near the fan, it is preferred to use embossed fins for the heat exchanger or at least one of the upper and lower parts (elements) of the heat exchanger. In this context, the heat exchanger or the heat exchanger elements each comprise tube loops with fins that interpose between the tubes. These fins are preferably embossed fins without any opening formed in the fins themselves.

Additional characteristics and effects of the heat exchanger unit can be obtained from the following description of embodiments. In the description of these embodiments, reference is made to the accompanying drawings.

Brief description of the drawings

Figure 1 shows a perspective view of a heat exchanger unit from one side;

Figure 2 shows a perspective view of the heat exchanger unit of Figure 1 from the opposite side;

Figure 3 shows a longitudinal section through the heat exchanger unit along a line that cuts a center of one of the fans; Y

Figure 4 shows a simulation of air distribution in the heat exchanger in a) a heat exchanger without a guide blade, b) a heat exchanger with a pointed guide blade and c) a heat exchanger with a blade Dolphin fin shaped guide.

Description of the embodiments

Figures 1 and 2 show a heat exchanger unit 1 according to an embodiment.

The heat exchanger unit 1 comprises a housing 2 that is configured for connection to an air duct of an air conditioner. In particular, the heat exchanger unit is configured as an "outdoor" unit of an air conditioner which, however, is arranged inside, particularly inside the roof of a building. Therefore, a first connection 3 is provided in the housing 2 for connection to an air duct that communicates the heat exchanger unit 1 with the outside of the building and to allow the suction of outside air into the housing 2. At the opposite end of the housing 2 there is a connection 4 provided for the connection of the heat exchanger unit 1 to the air duct that also leads to the outside of the building and to allow blowing out of air that has passed by heat exchanger 5 outside.

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The housing is substantially rectangular and flat, which means that the height H is smaller than the width W and the length L. In one embodiment, the height H is not more than 500 mm, preferably not more than 450 mm, more preferably no more than 400 mm and most preferred no more than 350 mm.

The heat exchanger unit 1 further comprises a heat exchanger 5 which can also be seen in Figure 1. However, the configuration of the heat exchanger 5 can best be seen from Figure 3. Figure 3 also represents a view heat exchanger side 5.

The heat exchanger 5 comprises an upper heat exchanger element 6 and a lower heat exchanger element 7. Both the upper and lower heat exchanger elements 6, 7 are flat or planar in shape and are located at an angle to included among them. Therefore, the heat exchanger 5 has a V-shape in which the "V" is oriented horizontally. A line CL passing through vertex 8 of the "V" is oriented horizontally, that is, along the length extension L of the heat exchanger unit 1. Line CL is also the central line of the exchanger of heat 5 or, in other words, a line of symmetry of its separation in terms of heat exchanger elements 6, 7.

The heat exchanger 5 is disposed within the air duct formed by the housing 2 so that all the air sucked through the opening in the connection 3 has to flow through the heat exchanger 5 without air being diverted from the exchanger of heat 5 at the top or bottom or sides of the heat exchanger 5 in the width W direction.

The upper and lower heat exchanger elements 6, 7 are connected to each other at vertex 8 by a connection element 9. The connection element is air impermeable and is also used to mechanically or physically connect the heat exchanger elements upper and lower 6, 7. Each of the heat exchanger elements 6, 7 comprises heat exchanger coils 10 (tube loops) and fins 11 disposed therebetween. The heat exchanger of the present embodiment is particularly applied to outdoor applications, that is as part of the heat source unit of an air conditioner. In this case, the fins of the upper and lower heat exchanger elements 6, 7 are preferably embossed fins. However, in case the heat exchanger is used for indoor applications (when indoor air passes through the heat exchanger), that is, as an indoor unit of an air conditioner, apersianized fins can be used. The apersianadas fins are preferably for a good flow of air through the heat exchanger since several holes are provided to allow air to flow through the fins. However, condensation water can accumulate in these holes and can lead to problems with frost formation during a heating operation if used as an outdoor application (i.e. when outside air passes through the heat exchanger) , when the ambient temperature is lower than approximately 7 ° C. To prevent these problems, in these cases it is preferred to use embossed fins.

Two backward curved centrifugal fans 20 are provided inside the housing. These backward curved centrifugal fans 20 each have a suction opening 21. In the side view (Figure 3), the central axis of the suction opening 21 and, therefore, of the fans 20 is substantially congruent or aligned with the central line CL of the heat exchanger 5. However, in some devices, it may be sufficient, as in the embodiment shown, that the central axis of the suction opening 21 and the central line CL of the heat exchanger 5 They are parallel but are displaced relative to each other in a horizontal direction.

In use, the fans 20 create a suction force in the suction opening 21 to induce a fluid flow (air flow) in the F direction. Thus, air, particularly outside air, is drawn through the connection 3 towards the open end 12 of the heat exchanger 5, passes through the upper and lower heat exchanger elements 6, 7 and is suctioned through the suction opening 21 to make it flow outwardly through the connection 4. As such, the housing 2 defines a conduit from connection 3 by means of heat exchanger 5 and fan 20 to connection 4. In this context, connection 3 and connection 4 define an inlet opening 13 and an outlet opening 14.

In addition, a drain pan 15 is provided inside the housing. The drain pan 15 is separated into two halves 16, 17 along the length L of the housing 2 in the side view. In Figure 3, the two halves 16, 17 are identified with the broken line, one half being located on the left side and one half located on the right side of the broken line. The drain pan 15 has a lower position 18 in which a drain opening 19 is provided. The bottom of the drain pan 15 is inclined towards the drain opening 19 and therefore towards the lowest position 18. By therefore, the water that falls from any component into the drain pan is guided directly to the drain opening 19 and to the lowest position 18 that is furthest from the fan 20. Therefore, the water is prevented from accumulated inside the drain pan, it can be sucked into the fan 20 and therefore through the opening 14 into the duct. The drain opening 19 connects directly to the drain so that the water drains directly.

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In addition, sound and / or thermal insulation 22 is provided within the housing 2 on the side opposite the drain pan 15 with respect to the CL line. In the cross section and therefore in a side view (Figure 3), the internal surfaces of the drain pan 15 and of the insulation 22 respectively directed towards the heat exchanger 15 must be approximated so that the conduit created within the housing 2 Be as symmetrical as possible.

In addition, the distance between the vertex 8 and the inlet of the suction opening 21 should be as short as possible to reduce the length. In particular, in the side view, the high speed of the fans should not overlap with the heat exchanger 5 and / or with the drain pan 15.

Figure 4 shows simulations of the distribution of air through the heat exchanger 5. Figure 4a) shows that the pressure drop can be increased at vertex 8 by the connection plate 9 compared to the pressure drop in the opening 12, thus providing a more uniform air distribution of the air (amount of air) flowing through the heat exchanger 5.

Even though the distribution of air flowing through the upper and lower heat exchanger elements 6, 7 is already relatively uniform in Figure 4a), due to the arrangement of the fan 20 downstream of the heat exchanger 5 and the provision of the connection element 9, it is evident that the air passing through the upper corner and lower corner portions 30, 31 at the very end of the upper and lower heat exchanger elements 6, 7 of the heat exchanger 5 It is relatively low compared to other parts.

In order to give uniformity to the air distribution, a guide blade 32 can therefore be provided which is preferably symmetrical to the center line CL and which has an aerodynamic surface directed towards the opening 12 of the heat exchanger 5. In others In other words, the front end 33 is directed towards the opening 12. The front end 33 of the guide blade 32 may be pointed as shown in Figure 4b) or the aerodynamic surface may have the shape of a dolphin fin such as is shown in Figure 4c).

The pressure drop at the vertex is increased by the connection element 9 and, therefore, a better air distribution can be achieved. In particular, the flow of fluid through the parts 30 and 31 is increased with respect to the parts close to the vertex 8. Therefore, the air distribution of the air flowing through the heat exchanger 5 is improved with a shovel guide 32.

Claims (8)

one. 10 fifteen twenty 25 2. 3. 30 Four. 35 5. 40 6. 7. 45 8. fifty 9. 55 10. 60 Heat exchanger unit (1) comprising: a housing (2) defining a conduit through which a fluid will flow, a fan (20) disposed in the housing (2) and configured to induce a flow of fluid through the conduit in a direction of flow (F), a heat exchanger (5) that is V-shaped in side view with a vertex (8) at one end and an opening (12) at the opposite end, the heat exchanger (5) being arranged in the conduit with the opening (12) directed towards the direction of flow (F), in which a line (CL) passing through the vertex (8) of the V-shaped heat exchanger (5) in the side view extends horizontally, in which the fan (20) is arranged downstream of the heat exchanger (5) in the direction of flow (F), characterized in that The heat exchanger (5) further comprises a connection element (9) that connects an upper heat exchanger part (6) and a lower heat exchanger part (7), the connection element (9) being arranged in the vertex (8) and being configured to block the flow of fluid through the heat exchanger (5) at the vertex (8), the connecting element (9) extending beyond the vertex (8) of the heat exchanger ( 5) covering a part of a lower surface of the lower heat exchanger part (7). Heat exchanger unit (1) according to claim 1, wherein the central axis of the fan (20) and the line (CL) of the V-shaped heat exchanger (5) are parallel in the side view, preferably at the same height in the side view. Heat exchanger unit (1) according to claim 1 or 2, wherein the fan (20) is a backward curved centrifugal fan. Heat exchanger unit (1) according to any one of the preceding claims, further comprising a guide blade (32), the guide blade (32) being disposed between opposite ends of the heat exchanger (5). Heat exchanger unit (1) according to claim 4, wherein the guide blade (32) has an aerodynamic surface with a line of symmetry that is aligned with the line (CL) of the heat exchanger (5) . Heat exchanger unit (1) according to claim 4 or 5, wherein the guide blade (32) has a leading edge (33) directed towards the direction of flow (F), the leading edge (33) being ) pointed. Heat exchanger unit (1) according to any one of claims 4 to 6, wherein the guide blade (32) has an aerodynamic surface in the form of a dolphin fin. Heat exchanger unit (1) according to any one of claims 4 to 7, wherein a shorter distance between the guide blade (32) and the heat exchanger (5) is not less than 15 mm. Heat exchanger unit (1) according to any one of the preceding claims, further comprising a drain pan (15), wherein the drain pan (15) has a drain opening (19) disposed therein half (17) of the drain pan (15) in the direction of flow (F) away from the fan (20), in which the drain pan (15) is configured to guide the water accumulated in the drain pan ( 15) away from the fan (20) to the drain opening (19). Heat exchanger unit (1) according to any one of the preceding claims, further comprising a drain pan (15) and an insulation (22) disposed on an opposite side of the drain pan (15) with respect to the heat exchanger (5), in which the insulation surfaces (22) and the drain pan (15) directed towards the heat exchanger (5) have approximate shapes in side view. Heat exchanger unit (1) according to one of the preceding claims, wherein the heat exchanger (5) comprises coils (10) and embossed fins (11) disposed between the coils (10).