US20130098588A1

US20130098588A1 - Air-air heat exchanger

Info

Publication number: US20130098588A1
Application number: US13/806,564
Authority: US
Inventors: Patrick Damizet; Xavier Boulanger
Original assignee: Aldes Aeraulique SA
Current assignee: Aldes Aeraulique SA
Priority date: 2010-06-23
Filing date: 2011-06-17
Publication date: 2013-04-25
Also published as: FR2961891B1; CA2800715A1; WO2011161360A2; FR2961891A1; WO2011161360A3

Abstract

Air-air heat exchanger (1) intended to be fitted to a room double-flow ventilation system comprising a plurality of plates (2) that are superposed to form a stack (3), each plate (2) comprising a plurality of flow channels forming a first air circulation volume (5) for a first air flow. The heat exchanger (1) further comprises spacer means designed to keep the plates (2) a distance apart so as to delimit a space (10) between two adjacent plates (2), these various spaces (10) between plates (2) forming an air circulation volume for a second air flow, first means for closing off the spaces (10) between the plates (2) at the two ends (6, 7) of the exchanger, second closing-off means (13), these second closing-off means (13) comprising, near the ends of the exchanger, two openings (20, 21), one for letting the second air flow in and the other for letting it out.

Description

TECHNICAL FIELD

The invention relates to an air-air heat exchanger for a controlled double-flow ventilation system, as well as a controlled mechanical ventilation system equipped with said exchanger.

BRIEF DISCUSSION OF RELATED ART

A controlled mechanical ventilation (CMV) system is a system designed to renew the air inside a technical or residential room.
In order to avoid losses due to air renewal, the ventilation established in a building is generally of the double-flow type, in particular static double-flows that are characterized by the fact that a static exchanger recovers the calories from the exhaust air removed from the building to make way for new air entering the building through a free recovery on simple heat exchange by conduction. In light of the current evolution in buildings, heating needs are tending to decrease significantly. In fact, the progress made owing to the design and use of new materials in terms of installation, windows, and heat bridge limitation have made it possible to decrease heat loss in residences significantly. However, in that type of habitat, losses due to air renewal should be decreased. The ventilation put in place is therefore generally of the double-flow type. In double-flow ventilation, an air-air network is designed to blow air into the main rooms or living rooms, and a second network removes air from the technical rooms or humid rooms. Controlled double-flow mechanical ventilation comprises two ventilators providing the same flow rate, one of which is designed to blow air into the building, and the other of which is designed to remove air from the building.
Quite often, the exchangers are made up of plastic plates adhered to one another (or made from welded aluminum), but whereof the plates delimit areas in contact on the welds.
The plates are generally identical.
In order to produce a high-performing heat exchanger, it is ideal to be able to benefit from a so-called counter-current exchange, i.e. in which the incoming and outgoing flows flow in substantially parallel, but opposite, directions.
Traditional exchangers are therefore generally faced with construction difficulties relative to pointed shapes that make it possible to have the flow separated by the plates themselves, but which creates a non-optimized exchange on large surface areas, since the flows are simply crossed, ultimately for a large proportion of the surface of the exchanger.
Document EP 2 071 267 describes a heat exchanger made from a stack of a plurality of parallelepiped plates, called honeycomb plates, each comprising a plurality of air circulation channels extending between two opposite ends of the plate, the other two ends being covered. The stack assumes a parallelepiped shape and is made such that the even plates and plates of the stack have ends in which the channels emerge respectively on two opposite lateral sides of the stack and on the other two lateral sides of the stack. In this way, the stack has, on each lateral side, a series of ends on which the air circulation channels emerge and covered ends, the even plates delimiting a first circulation volume and the odd plates delimiting a second circulation volume. During use, the incoming and outgoing air flows are each oriented toward a different circulation volume, one in the channels of the even plates, the other in the channels of the odd plates.
In this configuration, the heat exchanges take place at the interfaces between plates over the entire width of the exchanger, the incoming and outgoing flows being crossed. Such heat exchangers have a certain number of drawbacks: the heat exchange is not optimized, since the exchange takes place using a crossed arrangement, it requires a large number of plates for its design, and the heat exchange is done through two wall thicknesses, the lower wall of one plate and the upper wall of the plate positioned below it, which limits the performance of the heat exchanger.

BRIEF SUMMARY

The present invention aims to resolve these drawbacks.
The technical problem at the base of the invention is to provide a heat exchanger that offers both optimized heat exchange, in particular through the trajectory of the incoming and outgoing air in the exchanger, and reduced production costs relative to an exchanger using honeycomb plates. To that end, the invention relates to an air-air heat exchanger to be fitted to a room double-flow ventilation system, comprising:

- a plurality of identical and parallelepiped plates that are superimposed to form a generally parallelepiped stack, each plate comprising a plurality of air flow channels extending over the entire length of the plate, said channels being delimited by longitudinal partitions, all of the air circulation channels of the plates forming a first air circulation volume for guiding a first air flow in a first direction, over the entire length of the exchanger between a first end and a second end of the exchanger,
- characterized in that it comprises:
- spacer means designed to keep the plates a distance apart so as to delimit a space between two adjacent plates, these various spaces between plates forming an air circulation volume for guiding a second air flow in a second direction substantially parallel to the first direction,
- first means for closing off the spaces between the plates at the two ends of the exchanger,
- second means for closing off the spaces between the plates at the two longitudinal walls of the exchanger, i.e. those parallel to the circulation channels for the first air flow,
- the second closing-off means comprising, in one and/or the other of the two longitudinal walls, and near the two ends of the exchanger, two openings, one for letting the secondary flow in and the other for letting it out, respectively, arranged to guide the first and second air flows in opposite directions.

Such a heat exchanger using a stack of parallelepiped plates whereof the channels of the plates delimit a first circulation volume for an air flow along the stack and the spacing between plates, a second circulation volume for an air flow along the stack, makes it possible to produce a heat exchanger with a simple design and reduced cost, since one of the circulation volumes is made by the space between plates, producing an optimized heat exchange, since it uses a heat exchange according to the principle of counter-current flows over the entire length of the exchanger and only through one plate wall thickness.
Advantageously, the spacer means and the first closing-off means are made using at least two nozzle pieces respectively positioned at the first end and the second end of the exchanger.
Using nozzle pieces arranged at the two ends of the stack makes it possible, by using a single type of piece, both to keep the plates at a distance from each other and thereby delimit the second air circulation volume, and separate the first and second air flows.
Preferably, each nozzle piece comprises:

- at least one housing to house one side of a plate on which the channels emerge, this housing being provided with a through opening emerging in the circulation channels formed by the channels of the plate housed therein,
- at least one spacer forming the spacer means, the or each spacer maintaining a distance, alone or in cooperation with another spacer arranged on another end nozzle, from a plate housed in the nozzle piece of a directly adjacent plate in the stack,
- at least one closing-off member, for example such as a closing-off plate, forming the first closing-off means, said or each member closing off, alone or in cooperation with a closing-off member arranged on another nozzle piece, the space between a plate housed in the nozzle piece and a directly adjacent plate in the stack.

Using nozzle pieces comprising at least one housing for each plate, at least one spacer, and a closing-off member allows good maintenance of the distance between the adjacent plates, the plates being arranged in a housing and kept spaced apart by the spacers. The closing-off members make it possible to improve the separation of the air flows.
Advantageously, each spacer serves as a closing-off member.
The use of spacers as closing-off members makes it possible to guarantee good sealing of the space between plates, since the closing is done over the entire thickness of the spacer.
Advantageously, the nozzle piece or set of nozzle pieces equipping the first/second end of the exchanger closes the edge of the set of spaces between plates at the first/second end of the exchanger so as to separate the first and second circulation volumes at the first/second end of the exchanger.
The closing of one of the ends of the stack by the nozzle pieces equipping that end allows sealed closing off of the spaces between plates, thereby allowing good separation between the inlet/outlet of the first air circulation volume and the second air circulation volume.
Preferably, the second closing-off means comprise longitudinal ribs arranged between two directly adjacent plates of the stack, said ribs closing at least one longitudinal wall of the exchanger during formation of the stack.
The use of ribs on the plates serving as second closing-off means allows rapid assembly of the exchanger, since they do not require assembling an additional piece to close off the longitudinal wall(s) closed off by the ribs.
Advantageously, the second closing-off means comprise at least one closing-off plate fastened at the longitudinal wall of the exchanger so as to hermetically seal each inter-plate space on that same longitudinal wall, said closing-off plate preferably comprising second spacer means between plates such as spacers.
The use of a plate comprising spacers makes it possible to close off the wall over the entire height thereof, with a single piece.
Advantageously, the inlet and the outlet of the second air flow are arranged on the same lateral wall of the exchanger.
Such positioning of the air flows makes it possible to design an air-air circuit taking up a limited amount of space, since the air inlets and outlets are located on the same side.
Preferably, the inlet and outlet of the second air flow are respectively positioned on one and the other of the lateral walls.
Such positioning makes it possible to adapt the heat exchanger for installation in a ventilation circuit whereof the inlets and outlets for the second air flow are opposite one another without requiring the use of additional ventilation sheaths.
Advantageously, the heat exchanger also comprises a double collector for two flows of air arranged at each end of the stack, each collector making it possible to separate and orient the air flows either from the air-air network toward the corresponding circulation volume, or from the corresponding circulation volume toward the air-air network, the separation of the flow being obtained using the nozzle piece(s) arranged on the end of the stack on which the collector is installed, a portion elongated to extend the end of the stack serving as the partition to separate the air flows.
Using an elongated portion of the nozzle piece forming a partition cooperating with a double collector to separate the flows of air makes it possible to reduce the production costs for such a heat exchanger.
Preferably, the heat exchanger also comprises an air bypass corridor delimited by a chute adjacent to the stack, an air flow collector, and a valve mounted in the collector, movable between two positions, i.e. a first position in which it orients one of the air flows, preferably the second, toward the first or preferably the second circulation volume, and a second position in which it orients that same air flow toward the air bypass corridor.
Such a bypass corridor allows a periodic transmission of the air flows without performing a heat exchange between the first and second air flows, thereby allowing circulation in the air-air circuit without heat exchange when the latter is not required.
Preferably, the plates, the spacer means, and the first closing-off means are made from a plastic.
The invention also relates to a controlled room double-flow ventilation system, characterized in that it comprises an air-air heat exchanger as described above.
According to one feature, the heat exchanger is arranged such that the first flow of air circulating in the first air circulation volume of the exchanger is blown into the room, and the second air flow circulating in the second air circulation volume of the exchanger is removed from the room.
The second air flow circulates through the second air circulation volume. When the second air flow is removed from a bathroom, it has significant hygrometry. Frost therefore frequently forms inside the second circulation volume.
The second circulation volume is delimited by the inter-plate spaces and thus has a sufficient width to limit the risk of obstruction by the frost.

BRIEF DESCRIPTION OF THE DRAWINGS

In any case, the invention will be well understood using the following description in reference to the appended diagrammatic drawing showing, as a non-limiting example, several embodiments of this air-air heat exchanger.

FIG. 1 is a perspective view of a first exchanger;

FIG. 2 is an enlarged perspective view of a honeycomb plate forming the exchanger;

FIG. 3 is a perspective view of a honeycomb plate with longitudinal ribs;

FIG. 4 is a front view of the nozzle piece;

FIG. 5 is a perspective view of a stack of plates according to the embodiment of the heat exchanger made with a nozzle piece;

FIG. 6 is a longitudinal cross-sectional view of FIG. 5 along line A-A;

FIG. 7 is a front view of a heat exchanger equipped with specific collectors for the two air flows;

FIG. 8 is a perspective view of a heat exchanger equipped with double collectors for the two air flows and a bypass system for the blown air flow;

FIG. 9 is a partial perspective view of the exchanger of FIG. 8 in partial cross-section along plane B-B.

DETAILED DESCRIPTION

FIG. 1 shows an air-air heat exchanger 1 according to the invention designed to work with a room double-flow ventilation system comprising a first blown air flow and a second exhaust air flow. Such a heat exchanger 1 comprises:

- a plurality of plates 2 superimposed so as to form a stack 3, each plate 2 comprising a plurality of longitudinal air circulation channels 4 forming the first air circulation volume 5 for a first air flow between a first end 6 and second end 7 of the exchanger,
- spacer means 8, 9 arranged to keep the plates 2 a distance apart so as to limit the space 10 between two adjacent plates 2, these various spaces 10 between plates forming an air circulation volume 11 for a second air flow,
- first closing-off means 8, 9 for the spaces 10 between plates at both ends 6, 7 of the exchanger 1,
- second closing-off means 12, 13 for the spaces between the plates 2 at the two longitudinal walls 14 of the exchanger 1, i.e. those parallel to the circulation channels 4 of the first air flow.

The plates 2 forming the stack 3 are, as illustrated in FIG. 2, hollow plates 2 with identical dimensions and a parallelepiped shape preferably made from plastic. They each comprising a plurality of longitudinal channels 4 with a rectangular section. The channels are delimited by vertical and longitudinal partitions 15. These plates 2 may, depending on the manufacturing stresses and needs, comprise, as shown in FIG. 3, on one of the sides, a rib 12 forming a spacer means with an adjacent plate.
During the assembly of the heat exchanger 1, the plates 2 are superimposed at a distance from one another so as to form the stack 3 with a space 10 between two adjacent plates 2. The stack 10 thus formed has a generally parallelepiped structure. The space between the plates 2 forms the air circulation volume 11 for a second air flow. The maintenance of the distance between each plate 2 is obtained by using first spacer means 8, 9 arranged on the nozzle pieces 16 positioned at each end 6, 7 of the stack 3.
These nozzle pieces 16 are preferably made from plastic. The nozzle pieces 16 each comprise, as shown in FIG. 4:

- at least one housing 17 to house one side of the plate 2 in which the channels emerge, said housing 17 being provided with a through opening 18 emerging in the circulation channels 4 of the plate 2 that is housed therein,
- at least one spacer 8, 9 forming the spacer means 8, 9, the or each spacer 8, 9 maintaining, alone or in combination with another spacer arranged on another nozzle piece, a distance between a plate 2 housed in the nozzle piece 16 and a directly adjacent plate in the stack 3,
- at least one closing- off member 8, 9, forming the first closing-off means 8, 9, this or each member 8, 9 closing off, alone or in cooperation with a closing-off member arranged on another nozzle piece, the space 10 between a plate 2 housed in the nozzle piece 16 and a directly adjacent plate in the stack 3.

The height of the spacers is chosen to adapt the passage section of the second flow to the desired aeraulic conditions, for example to account for pressure losses on the intake network and the exhaust network.
Each nozzle piece 16 may comprise either a housing for a single plate 2 or, as illustrated in FIGS. 4, 5 and 6, five housings or ten housings. In the configuration with five housings, a nozzle piece 16 comprises four inner spacers 8 separating the plates 2 from one another arranged in the housings 18 of the nozzle piece 16, and two outer spacers 9 arranged at each end of the nozzle piece 16. The outer spacers 9 make it possible, in cooperation with an outer spacer of a directly adjacent nozzle piece in the stack 3, to close off the space 10 between the stack formed by the plates 2 housed in the nozzle piece 16 and the plates housed in the directly adjacent nozzle piece of the stack 3.
In this way, the set of nozzle pieces 16 equipping one end 6, 7 of the exchanger 1 closes off, as shown in FIG. 7, the edge of the set of spaces 10 between plates 2 at the end 6, 7 of the exchanger 1. This closing off is a separation between the first 5 and second 11 air circulation volume at the end 6, 7 equipped with the nozzle pieces 16.
The exchanger 1 also comprises, to close off the longitudinal walls 14 of the exchanger 1 and so as to close the sides of the second circulation volume 11, second closing off means 12, 13.
These second means 12, 13 may, if the plates 2 used to produce the exchanger 1 are provided therewith, be ribs 12 arranged on one side of the plate 2. These ribs 12 close off the longitudinal walls 14 formed by the sides of the plates 2 on which they are arranged.
These second closing-off means 12, 13 may also be a closing-off plate 13 fastened at the longitudinal walls 14 of the exchanger 1 so as to hermetically seal, on that same lateral wall 14, the spaces 10 between plates 2. This closing-off plate 13 may also comprise, as illustrated in FIG. 5, second spacer means 19 between plates 2 such as the spacers 19. The spacer means 19 facilitate the production of the space between plates 2 during the assembly of the heat exchanger 1.
The second closing-off means 12, 13, whether made using ribs 12 or a closing-off plate 13, comprise, in one and/or the other of the two longitudinal walls 14 and close to the ends 6, 7 of the exchanger 1, two openings 20, 21 for the second circulation volume 11, respectively for the inlet 20 and the outlet 21 for the second air flow.
During assembly, the heat exchanger is generally equipped with flow collectors 22, 23, said collectors being able to be either collectors 22 specific to each flow, as shown in FIGS. 1 and 7, or double collectors 23 for both air flows, as shown by FIGS. 8 and 9.
For an assembly with single collectors 22, the collectors are arranged at the ends of the inlet 20 and the outlet 21 of the second circulation volume 11. The first portion of the ventilation circuit, that of the blown flow, is sealably connected to the inlet 6 and the outlet 7 of the first air circulation volume 5 by the nozzle pieces 16. The second portion of the ventilation circuit, that of the exhaust flow, is sealably connected to the inlet collector 22 and the outlet collector 22. In this way, the blown and exhaust flows both pass through the heat exchanger 1, the inlets and outlets of those flows being opposite, allowing a heat exchange between the two flows that circulate counter-current. The blown flow is thus heated by the exhaust flow, limiting heat losses related to the air renewal in the room.
For an assembly comprising double collectors 23, the intake and exhaust air flows are collected by the collectors 23. The separation of these two air flows and the respective guiding toward the corresponding inlets 6, 20 and outlets 7, 21 are done by means of nozzle pieces 16. In fact, the nozzle pieces 16 may comprise, for installation with a double collector 23, an elongated portion 24 in the extension of the end of the stack 3 serving as the separating partition.
During an installation comprising a double collector 23, it is also possible to produce a so-called bypass installation, i.e. comprising an air bypass corridor 25. This type of heat exchanger comprises, as shown in FIGS. 8 and 9, a chute 26 adjacent to the stack 3, delimiting the air bypass corridor 25, and a so-called bypass valve 27 mounted in one of the collectors 23 such that it can move between two positions, i.e. a first position in which it orients the second air flow toward the second circulation volume 11, and a second position in which it orients that same air flow toward the air bypass corridor 25. In this way, the second air flow, the exhaust flow, may, as a function of the position of the valve 27, either be oriented toward the second circulation volume 11 of the exchanger 1, thereby allowing a heat exchange with the blown flow, or toward the bypass circulation corridor 25, without a heat exchange.
During the installation of a heat exchanger comprising double collectors 23 in a ventilation circuit, the first portion and the second portion of the ventilation circuit are connected to the double collectors 23 of the heat exchanger 1, the blown flow oriented toward the first air circulation volume 5 of the exchanger 1 and the exhaust flow oriented toward the second air circulation volume 11. In this way, using a principle similar to the use of an exchanger comprising several collectors 22, an optimized heat exchange is obtained with the additional advantage, due to the use of the bypass valve 27, of being able to separate the blown flow from the exhaust flow thermally and periodically.
The invention is of course not limited solely to the embodiments of this heat exchanger described above as examples, but on the contrary encompasses all alternative embodiments.

Claims

1. An air-air heat exchanger to be fitted to a room double-low ventilation system, comprising:

a plurality of identical and parallelepiped plates that are superimposed to form a generally parallelepiped stack, each plate comprising a plurality of air flow channels extending over the entire length of the plate, said channels being delimited by longitudinal partitions, all of the air circulation channels of the plates forming a first air circulation volume for guiding a first air flow in a first direction, over the entire length of the exchanger between a first end and a second end of the exchanger,

characterized in that it comprises:

spacer means designed to keep the plates a distance apart so as to delimit a space between two adjacent plates, these various spaces between plates forming an air circulation volume for guiding a second air flow in a second direction substantially parallel to the first direction,

first means for closing off the spaces between the plates at the two ends of the exchanger,

second means for closing off the spaces between the plates at the two longitudinal walls of the exchanger, parallel to the circulation channels for the first air flow,

Wherein the second closing-off means comprises, in one and/or the other of the two longitudinal walls, and near the two ends of the exchanger, two openings, one for letting the secondary flow in and the other for letting it out, respectively, arranged to guide the first and second air flows in opposite directions.

2. The air-air heat exchanger according to claim 1, wherein the spacer means and the first closing-off means are made using at least two nozzle pieces respectively positioned at the first end and the second end of the exchanger.

3. The air-air heat exchanger according to claim 2, wherein each nozzle piece comprises:

at least one housing to house one side of a plate on which the channels emerge, this housing being provided with a through opening emerging in the circulation channels formed by the channels of the plate housed therein,

at least one spacer forming the spacer means, the or each spacer maintaining a distance, alone or in cooperation with another spacer arranged on another end nozzle, from a plate housed in the nozzle piece of a directly adjacent plate in the stack,

at least one closing-off member, for example such as a closing-off plate, forming the first closing-off means, said or each member closing off, alone or in cooperation with a closing-off member arranged on another nozzle piece, the space between a plate housed in the nozzle piece and a directly adjacent plate in the stack.

4. The air-air heat exchanger according to claim 3, wherein each spacer serves as a closing-off member.

5. The air-air heat exchanger according to claim 3, wherein the nozzle piece or set of nozzle pieces equipping the first/second end of the exchanger closes the edge of the set of spaces between plates at the first/second end of the exchanger so as to separate the first and second circulation volumes at the first/second end of the exchanger.

6. The air-air heat exchanger according to claim 1, wherein the second closing-off means comprise longitudinal ribs arranged between two directly adjacent plates in the stack, said ribs closing at least one longitudinal wall of the exchanger during formation of the stack.

7. The air-air heat exchanger according to claim 1, wherein the second closing-off means comprise at least one closing-off plate fastened at the longitudinal wall of the exchanger so as to hermetically seal each inter-plate space on that same longitudinal wall, said closing-off plate preferably comprising second spacer means between plates such as spacers.

8. The air-air heat exchanger according to claim 1, wherein the inlet and the outlet of the second air flow are arranged on the same lateral wall of the exchanger.

9. The air-air heat exchanger according to claim 1, wherein the inlet and outlet of the second air flow are respectively positioned on one and the other of the lateral walls.

10. The air-air heat exchanger according to claim 2, further comprising a double collector for two flows of air arranged at each end of the stack, each collector making it possible to separate and orient the air flows either from the air-air network toward the corresponding circulation volume, or from the corresponding circulation volume toward the air-air network, the separation of the flow being obtained using the nozzle piece(s) arranged on the end of the stack on which the collector is installed, a portion elongated to extend the end of the stack serving as the partition to separate the air flows.

11. The air-air heat exchanger according to claim 1, further comprising an air bypass corridor delimited by a chute adjacent to the stack, an air flow collector, and a valve mounted in the collector, movable between two positions, comprising a first position in which it orients one of the air flows, toward the first or the second circulation volume, and a second position in which it orients that same air flow toward the air bypass corridor.

12. The air-air heat exchanger according to claim 1, wherein the plates, the spacer means, and the first closing-off means are made from a plastic.

13. A controlled room double-flow ventilation system, comprising an air-air heat exchanger according to claim 1.

14. The controlled room double-flow ventilation system according to claim 13, wherein the heat exchanger is arranged such that the first flow of air circulating in the first air circulation volume of the exchanger is blown into the room, and the second air flow circulating in the second air circulation volume of the exchanger is removed from the room.