WO2015171052A2

WO2015171052A2 - A ventilation device

Info

Publication number: WO2015171052A2
Application number: PCT/SE2015/050484
Authority: WO
Inventors: Mattias Svensson; Karl-Henrik Nilsson
Original assignee: Smartvent Sverige Ab
Priority date: 2014-05-05
Filing date: 2015-04-30
Publication date: 2015-11-12
Also published as: SE1450530A1; SE540183C2; WO2015171052A3

Abstract

A ventilation device (10) for exchanging room air, comprising a casing (15) having an internal wall (22) dividing the casing (15) into a first compartment (23) and a second compartment (24), each of said compartments (23, 24) having a first opening (25a, 25b) and a second opening (26a, 26b), wherein the ventilation device further comprises a first heat exchanger (11a) arranged in the first compartment, a second heat exchanger (11b) arranged in the second compartment, a first fan (12a) arranged in the first compartment and a second fan (12b) arranged in the second compartment, said fans being arranged for alternatingly providing, in a first direction, an exhaust airflow (13) from the room to an air supply through the heat exchangers, and alternatingly providing, in an opposite second direction, a supply airflow (14) from the air supply to the room through the heat exchangers.

Description

A VENTILATION DEVICE

FIELD OF THE INVENTION The invention relates to a ventilation device for exchanging room air.

Air in premises, such as rooms in houses, offices, commercial buildings, industrial buildings and other types of buildings, are ventilated to exchange air in one or more of the rooms. For example, such systems and methods are arranged for ventilating a dwelling or a part thereof. Fresh air is supplied from an air supply, such as ambient air, i.e. outdoor air, or air from another space, to the rooms through ventilation devices. Further, exhaust air is conveyed from the one or more rooms and, for example, to the outside of the building. This type of ventilation devices comprises a regenerative heat exchanger for recovering thermal energy and for reducing energy loss when providing fresh air to the rooms and transporting exhaust air out from the rooms.

BACKGROUND AND PRIOR ART

There are several different types of ventilation devices comprising re- generative heat exchangers in the prior art.

Regenerative heat exchange is a process where heat from a hot fluid, such as an exhaust airflow, is intermittently stored in a thermal storage medium before it is transferred to a cold fluid, such as a supply airflow of fresh air. To accomplish this, the exhaust airflow, for example, is brought into contact with the thermal storage medium, wherein thermal energy is transferred from the exhaust airflow to the thermal storage medium. Then, the supply airflow is brought into contact with the thermal storage medium, wherein thermal energy is transferred from the thermal storage medium to the supply airflow.

In practical applications, in order to maximize the surface area and performance of the regenerative heat exchange process, the thermal storage medium is usually a material matrix with pervading channels. The exhaust airflow and supply airflow are brought into contact with the matrix by alternat- ingly moving through the matrix in a re-occurring loop. Hence, a single airflow is conveyed through the matrix in a cyclical reversible flow. One period or cycle is the time from which the exhaust airflow enters the matrix in a first direction and until the supply airflow exits the matrix in the opposite direction. Hence, the supply airflow and the exhaust airflow move alternatingly through the matrix.

One problem with ventilation devices according to prior art is that they require a lot of space.

Another problem with such prior art devices is that they can be complicated to install and require installation of cables between different ventilation devices.

SUMMARY OF THE INVENTION

An object of the present invention is to avoid the problems of the prior art. The invention results in a compact en effective ventilation device being simple to install and which provides efficient ventilation. The present invention relates to a ventilation device for exchanging room air in at least one room, comprising a casing having an internal wall dividing the casing into a first compartment and a second compartment, each of said compartments having a first opening and a second opening, wherein the device further comprises a first heat exchanger arranged in the first com- partment, a second heat exchanger arranged in the second compartment, a first fan arranged in the first compartment and a second fan arranged in the second compartment, said fans being arranged for alternatingly providing, in a first direction, an exhaust airflow from the at least one room to an air supply through the heat exchangers, and alternatingly providing, in an opposite sec- ond direction, a supply airflow from the air supply to the at least one room through the heat exchangers. Hence, two or more compartments having a fan and a heat exchanger, such as a regenerative heat exchanger, is combined in a single joint casing and can work together in such as way that the total net airflow in ventilation applications is adjustable down to zero as per requirement (fluid going into the room or confinement minus the fluid going out of the room or confinement equals zero). Hence, two or more airflows can be handled by the ventilation device simultaneously. Further, the ventilation device results in a compact and efficient ventilation device which is easy to install and set up.

The first opening can be arranged in a rear side of the device, and the second opening can be arranged perpendicular to the first opening, e.g. in lateral sides of the casing. Hence, an efficient handling of the exhaust airflow and supply airflow is provided which makes it possible to have a compact design of the ventilation device and efficient ventilation.

The internal wall can divide the first opening to a first opening part leading to the first compartment and a second opening part leading to the second compartment. The first opening can be arranged centrally in the rear side of the casing. An airflow pipe can be connected to the first opening and can be arranged for connecting the first and second compartments to supply air. The airflow pipe can comprise a first duct to the first compartment and a second duct to the second compartment. Hence, one or several ducts that enable separation of two or more airflows (typically supply air and exhaust air) can be arranged in one single round hole in a building wall and still utilizing the full cross-section area of the round wall hole. The separation of the air flows can be realized by either using one or more internal walls inside the airflow pipe or joining one or more pipes to form a joint airflow pipe having substantially circular cross section. Utilizing the full cross-section area of the hole in the wall goes against previous solutions using two circular pipes in one hole in the wall. Using two pipes in one hole in the wall equates to utilizing maximum 50% of the hole in the wall. According to one aspect of the invention 50% or more of the cross-section area of the hole in the wall, such as substantially the entire hole, can be utilized for the airflows. The innovation leads to the possibility of utilizing the full cross-section area of one single hole in walls of the building for both exhaust and supply flow to cut costs, shorten installation time and improve the handling of the flows. The external geometry of the pipe can be round, enabling the possibility of utilizing the full cross-section of drilled/cut holes in walls of the building. This solution can be realized through either one pipe with a fix or removable internal wall or by having two pipes, that are half-circular shaped, together forming the overall externally round geometry. The heat exchanger can be a fixed matrix generative heat exchanger having, for example, a flow length less than 100 mm or 50-80 mm. According to one aspect of the innovation the flow length in the regenerative heat exchanger matrix is shortened compared to prior art with minimal impact on dry energy recovery efficiency. This is made possible by use of the fixed matrix, such as a ceramic fixed matrix having through channels for the airflow, resulting in advantageous heat transport characteristics. It has been found that flow length less than 100 mm and even down to 50 mm still can result in a dry energy recovery efficiency of 80 % and upwards. The fans can be axial fans arranged on a tray or a wall element. Said tray can be arranged in a structure of sound and/or vibration dampening material, which structure is arranged in contact with the inside of the casing. Prior art vibration dampening solutions for axial fans feature a compromise between size and leakage and are not sufficiently effective. Generally the inside of ventilation device casings most often feature sound insulation or sound dampening material. Closely related to sound dampening materials are materials that are designed towards vibration dampening. However, according t one aspect of the innovation the fans can be attached directly or indirectly, such as through the fan tray, by a face of the fan (inlet or outlet side) to sound and vibration dampening material. The sound and vibration dampening material can be lined to the inside of the ventilation unit casing. A fan tray with the fan mounted on it can be slid into grooves in two side parts of the sound/vibration dampening material structure. The remaining two sides of the fan tray can be in contact with the top and bottom parts of the sound/vibration dampening material structure, e.g. under tension. This solution enables limited contact between the fan tray and the sound/vibration dampening material and yet effectively separating the back and front of the fan (meaning no/little leakage).

Further characteristics and advantages of the present invention will become apparent from the description of the embodiments below, the appended drawings and the dependent claims. SHORT DESCRIPTION OF THE DRAWINGS

The invention will now be described more in detail with the aid of embodiments and with reference to the appended drawings, in which

Fig. 1 a is a schematic perspective view illustrating the operation of a ventilation device comprising a regenerative heat exchanger, wherein an exhaust airflow is conveyed in a first direction and thermal energy in the exhaust airflow is recovered by the heat exchanger in a first part of a working cycle,

Fig. 1 b is a schematic view according to Fig. 1 a, in which supply airflow is conveyed in a second direction and is heated by the heat exchanger in a second and final part of the working period, Fig. 2 is a schematic perspective view of a ventilation device according one embodiment of the invention,

Fig. 3 is a schematic section view of the ventilation device according to Fig.

2,

Fig. 4a is a schematic perspective view from above of a ventilation device according to one embodiment arranged in a room and illustrating an exhaust airflow and a supply airflow in a first part of a working cycle, Fig. 4b is a schematic perspective view according to Fig. 4a, illustrating the exhaust airflow and the supply airflow in a second and final part of the working cycle,

Fig. 5a is a schematic perspective view from above of the ventilation device according to Fig. 2 arranged in a room and illustrating an exhaust airflow and a supply airflow in a first part of the working cycle, Fig. 5b is a schematic perspective view according to Fig. 5a, illustrating the exhaust airflow and the supply airflow in a second and final part of the working cycle, Fig. 6 is a schematic perspective view of an airflow pipe of the ventilation device according to one embodiment.

Fig. 7 is a schematic front view of the airflow pipe according to Fig. 6, and Fig. 8 is a schematic perspective view of a fan of the ventilation device according to one embodiment.

THE INVENTION Referring to Fig. 1 a and Fig. 1 b a general operation of a ventilation device 10 comprising a regenerative heat exchanger 1 1 is illustrated schematically. The ventilation device 10 is, for example, arranged for ventilating at least one room, such as a dwelling. The ventilation device 10 comprises a heat exchanger 1 1 and a fan 12 for providing an airflow through the heat ex- changer 1 1 . The heat exchanger 1 1 comprises a thermal storage medium in the form of a fixed material matrix with through conduits for the airflow. For example, the thermal storage medium comprises a ceramic material. The heat exchanger 1 1 is arranged for recovering heat from hot air, wherein thermal energy from the hot air is transferred to the thermal storage medium of the heat exchanger 1 1 . Then, when cold air is transported through the heat exchanger heat is transferred to the cold airflow, which is heated. Correspondingly, the heat exchanger 1 1 can be used for cooling an airflow.

With reference to Fig. 1 a and Fig. 1 b the airflow through the ventilation device 10 is illustrated by means of an arrow, wherein the striped part repre- sent hot air and the plain part represent cold air. In the example illustrated in Fig. 1 a the fan 12 provides an exhaust airflow 13 from the at least one room to an air supply. Heat from the exhaust airflow 13 is transferred from the building comprising one or more rooms to the air supply in a first direction by means of the fan 12. Said air supply is, for example, air outside of the build- ing, such as outdoor ambient air, or another space containing fresh air. Heat from the exhaust airflow 13 is recovered by the heat exchanger 1 1 . Then, after a period of time or based on another parameter the fan 12 changes direction to provide a supply airflow 14 of fresh air into the one or more rooms of the building from the air supply, which is illustrated in Fig. 1 b, wherein the supply airflow 14 is heated when passing the heat exchanger 1 1 . Hence, the fan 12 is intermittently, i.e. periodically and cyclically, moving air in the first direction and the second direction for providing the exhaust airflow 13 and the supply airflow 14, wherein the airflow goes back and forth through the ventilation device 10 and the heat exchanger 1 1 . The exhaust airflow 13 and supply airflow 14 are brought into contact with the heat exchanger 1 1 by al- ternatingly moving through heat exchanger 1 1 in a re-occurring loop. Hence, a single airflow is conveyed through the heat exchanger 1 1 in a cyclical reversible flow. One period or cycle is the time from which the exhaust airflow 13 enters the ventilation device 10 in the first direction and until the supply airflow 14 exits the ventilation device 10 in the opposite direction. Hence, the supply airflow 14 and the exhaust airflow 13 move alternatingly through the heat exchanger 1 1 . For example, during a first part of the period the exhaust airflow 13 is exclusively directeded through the heat exchanger in the first direction, wherein the supply airflow 14 is exclusively directed through the heat exchanger in the second direction during a second part of the period. The heat exchanger 1 1 is, for example, a fixed matrix generative heat exchanger having through channels for the airflow. For example, the air is moved back and forth through the same channels in the heat exchanger 1 1 , so that the hot exhaust airflow is transported through the channels in the first direction during the first part of the period and the cold supply airflow is transported through the very same channels in the opposite second direction during the second part of the period.

With reference to Figs. 2 and 3 the ventilation device 10 according to one embodiment of the invention is illustrated. The ventilation device 10 comprises a casing 15 having a front side 16 and an opposite rear side 17. In the illustrated embodiment, the casing 15 is box-shaped having an upper side 18, an opposite lower side 19, a left side 20 and a right side 21 , the up- per, lower, left and right sides 18-21 extending between and being perpendicular to the front and back sides 16, 17. Alternatively, the casing 15 is cylinder shaped or formed with another suitable shape having areas corresponding to the upper, lower, left and right sides 18-21 . The ventilation device 10 comprises an internal wall 22 dividing the casing 15 into a first compartment 23 and a second compartment 24. In the illustrated embodiment, the first and second compartments 23, 24 are similarly designed and are inverted in relation to each other. The first and second compartments 23, 24, respectively, comprise a first opening 25a, 25b and a second opening 26a, 26b. The first opening 25a, 25b is connected to an airflow pipe 27 connecting the ventilation device 10 to the air supply, such as ambient air, for directing the supply airflow and the exhaust airflow between the air supply and the compartments 23, 24 of the ventilation device 10.

Hence, the airflow pipe 27 is arranged for extending through a wall of a build- ing. The airflow pipe 27 is connected to the rear side 17 of the ventilation device 10. The exhaust airflow and the supply airflow from the air supply and into the compartments 23, 24 of the ventilation device 10 through the airflow pipe 27 are illustrated by means of the arrows A and B in Fig. 2.

The second openings 26a, 26b are arranged for directinging exhaust airflow and supply airflow between the at least one room and the compartments 23, 24 of the ventilation device 10, which is illustrated by means of the arrows C and D in Fig. 2. For example, the second opening 26a of the second compartment 24 is arranged in the left side 20 of the casing 15, wherein the second opening 26b of the first compartment 23 is arranged in the right side 21 of the casing 15. Alternatively, the second openings 26a, 26b are arranged in the upper and lower sides 18, 19. Hence, the second openings 26a, 26b are arranged in a side of the casing 15 being perpendicular to the rear side 17.

The ventilation device 10 or the casing 15 is, for example, formed with a thickness or depth x of 100-200 mm or 100-150 mm, a width y of 200-500 mm, 250-400 mm, 300-400 mm or 350-380 mm, and a height z of 200-500 mm, 250-400 mm or 300 mm. Each of the compartments 23, 24 comprise the heat exchanger 1 1 and the fan 12 for providing the exhaust airflow and the supply airflow alternating- ly through the first and second compartments 23, 24. Hence, the first compartment 23 comprises a first heat exchanger 1 1 a and a first fan 12a, where- in the second compartment 24 comprises a second heat exchanger 1 1 b and a second fan 12b. When the exhaust airflow is directed through the first compartment 23, the supply airflow is directed through the second compartment 24 and vice versa. In the illustrated embodiment the heat exchanger 1 1 a, 1 1 b is arranged at the second opening 26a, 26b wherein the fan 12a, 12b is ar- ranged between the heat exchanger 1 1 a, 1 1 b and the first opening 25a, 25b. Alternatively, the fan 12a, 12b is arranged at the second opening 26a, 26b.

In the illustrated embodiment the first opening 25a, 25b of the first compartment 23 and the second compartment 24 are formed by a single opening, such as a single circular hole, in the casing 15, said opening being divided by the internal wall 22. Hence, in the illustrated embodiment, the first opening 25a, 25b of the first and second compartments 23, 24 are semicircular, wherein the flat side of the first openings 25a, 25b is formed by the internal wall 22.

The heat exchanger 1 1 a, 1 1 b is, for example, a fixed matrix generative heat exchanger having through channels for the airflow. According to one embodiment, the heat exchanger 1 1 a, 1 1 b comprises a ceramic material. The thickness t of the heat exchanger 1 1 a, 1 1 b, i.e. the distance from the airflow entrance side to the airflow exit side is, for example, less than 90 mm, less than 75 mm or less than 60 mm. For example, the thickness t of the heat exchanger 1 1 is about 50 mm.

In the illustrated embodiment, the fans 12a, 12b, respectively, are arranged in a wall element 28 connected to the inside of the casing 15 for increasing the efficiency of the fans 12a, 12b. According to one embodiment the ventilation device 10 has the capacity of providing an airflow of at least 0.3 l/s per m² or at least 0.35 l/s per m² For example, the ventilation device 10 has a range of 6-16 l/s with a dry energy recovery efficiency of more than 80 %. With reference to Figs. 4a and 4b the operation of the ventilation device 10 is illustrated schematically in a simplified manner. The ventilation device 10 is arranged in a room 29 or a confinement for exchanging the air therein. Hence, the ventilation device 10 is arranged for simultaneously providing the exhaust airflow 13 and the supply airflow 14, wherein the exhaust airflow 13 is directed through the first compartment 23 and the supply airflow 14 is directed through the second compartment 24. Thermal energy is recovered by means of the heat exchangers 1 1 a, 1 1 b. The fan 12a of the first compartment 23 is arranged for providing the exhaust airflow 13 from the room 29 to the air supply in a first direction through the heat exchanger 1 1 a of the first compartment 23, while the fan 12b of the second compartment 24 is arranged for providing the supply airflow 14 from the air supply to the room 29 in an opposite second direction through the heat exchanger 1 1 b of the second compartment 24, which is illustrated in Fig. 4a. Then, after a prede- termined period of time or based on another parameter, the airflow direction through the compartments 23, 24 is switched, so that the supply airflow 14 is directed through the first compartment 23 and the exhaust airflow 13 is directed through the second compartment 24, which is illustrated in Fig. 4b. For example, the direction of rotation of the fans 12a, 12b is switched to reverse the airflows. According to one embodiment, the operation of the fans 12a,

12b are synchronized or coordinated, so that the airflow direction through the first and second compartments 23, 24 is switched simultaneously or with a minor time delay to reduce noise.

With reference to Figs. 5a and 5b the operation of the ventilation de- vice 10 is illustrated schematically according to one embodiment. A first part, such as a warm part, of the exhaust airflow 13 is sucked into the first compartment 23 through the second opening 26a by means of the fan 12a inside the first compartment 23. Hence, the first part of the exhaust airflow 13 is sucked into the first compartment 23 in the lateral direction from the side and thus perpendicular to the rear side of the casing 15. Any thermal energy is recovered by the heat exchanger 1 1 a and stored therein. A second part, such as a cold part, of the exhaust airflow 13 is blown out from the first compartment 23 through the first opening 25a in a direction perpendicular to the first part of the exhaust airflow 13. Simultaneously, the supply airflow 14 is provided through the second compartment 24 in the opposite direction. Then, as illustrated in Fig. 5b, the airflows are reversed through the first and second compartments 23, 24 and the thermal energy is recovered. With reference to Figs. 6 and 7 the airflow pipe 27 is illustrated according to one embodiment. The airflow pipe 27 is arranged for directing two airflows simultaneously in opposite directions, i.e. the exhaust airflow from the first or second compartment and the supply airflow to the first or second department. Hence, the airflow pipe 27 is arranged for directing both the supply airflow and the exhaust airflow to and from the ventilation device 10. According to the illustrated embodiment the airflow pipe 27 comprises a first duct 30 and a second duct 31 . For example, the first and second ducts 30, 31 are formed by a wall 32 dividing the airflow pipe 27 into the first and second ducts 30, 31. Alternatively, the first and second ducts 30, 31 are joined to form the airflow pipe 27. The first duct 30 is connected to the first compartment 23 and the second duct 31 is connected to the second compartment 24. The cross section of the airflow pipe 27 is, for example, circular, wherein the cross section of the first duct 30 is semi-circular and the cross section of the second duct 31 is semi-circular. With reference to Fig. 8 the fan 12 is illustrated according to one embodiment. For example, the fan 12 is an axial fan and provides the airflows in a direction along an axis of rotation of the fan 12. The fan 12 is arranged in a wall element 28 being connected to the inside of the casing 15 through a bottom 33, a top part 34 and side parts 35. In Fig. 8 one of the side parts 35 has been removed. The bottom, 33, the top part 34 and the side parts 35 are arranged in a sound dampening and/or vibration dampening material and are arranged in direct contact with the inside of the casing 15 to support the wall element 28 carrying the fan 12 in a sound and/or vibration dampened manner. Hence, the bottom 33, the top part 34 and the side parts 35 form a struc- ture of dampening material supporting the wall element 28 with the fan 12. For example, the wall element 28 carrying the fan 12 is slid into grooves in the bottom 33, the top part 34 and the side parts 35 of dampening material. Said grooves extends a distance into the bottom 33, the top part 34 and the side parts 35 but not through them, wherein the wall element 28 is not in contact with the casing 15. Hence, the entire periphery of the wall element 28 is enclosed by the structure formed by the bottom 33, the top part 34 and the side parts 35.

Claims

1 . A ventilation device (10) for exchanging room air in at least one room (29), comprising a casing (15) having an internal wall (22) dividing the casing (15) into a first compartment (23) and a second compartment (24), each of said compartments (23, 24) having a first opening (25a, 25b) and a second opening (26a, 26b), wherein the ventilation device (10) further comprises a first heat exchanger (1 1 a) arranged in the first compartment (23), a second heat exchanger (1 1 b) arranged in the second compartment (24), a first fan (12a) arranged in the first compartment (23) and a second fan (12b) arranged in the second compartment (24), said fans (12a, 12b) being arranged for alter- natingly providing, in a first direction, an exhaust airflow (13) from the at least one room (29) to an air supply through the heat exchangers (1 1 a, 1 1 b), and alternatingly providing, in an opposite second direction, a supply airflow (14) from the air supply to the at least one room (29) through the heat exchangers (1 1 a, 1 1 b).

2. A ventilation device according to claim 1 , wherein the first opening (25a, 25b) is arranged in a rear side (17) of the casing (15), and wherein the sec- ond opening (26a, 26b) is arranged perpendicular to the first opening (25a, 25b).

3. A ventilation device according to claim 2, wherein the second opening (26a) of the first compartment (23) is arranged on a first lateral side (21 ) of the device, wherein the second opening (26b) of the second compartment (24) is arranged in an opposite second side (20) of the casing (15).

4. A device according to any of the preceding claims, wherein the internal wall (22) divides a hole in the casing (15) to the first opening (25a) leading to the first compartment (23) and the first opening (25b) leading to the second compartment (24).

5. A device according to any of the preceding claims, comprising an airflow pipe (27) connected to the first opening (25a, 25b) and being arranged for connecting the first and second compartments (23, 24) to supply air.

6. A device according to claim 5, wherein the airflow pipe (27) comprises a first duct (30) to the first compartment (23) and a second duct (31 ) to the second compartment (24).

7. A device according to claim 6, wherein the first duct (30) and the second duct (31 ) together form a pipe having circular cross section.

8. A device according to any of the preceding claims, wherein the heat exchanger (1 1 a, 1 1 b) is a fixed matrix regenerative heat exchanger.

9. A device according to any of the preceding claims, wherein the heat exchanger flow length is less than 100 mm or 50-80 mm.

10. A device according to any of the preceding claims, wherein the fans (12a, 12b) are axial fans.

1 1 . A device according to any of the preceding claims, wherein the fans (12a, 12b) are connected to the inside of the casing (15) through a sound and/or vibration dampening material.