SE545085C2 - A battery device for a ventilation system - Google Patents

Abstract

A battery device (10) arranged to be installed in a ventilation system (1) and arranged to extract energy from a flow (F) of air from said air, said battery device (10) comprises: a housing (11 ) arranged to receive said flow (F) of air through a first end (11 a) and at least one bent conduit arrangement (12) arranged inside said housing (11 ) to extend in a direction from the first end of the housing (11 a) to a second end of the housing (11b), whereby said flow (F) of air will pass along the bent conduit arrangement (11 ) when said flow (F) of air is received by said housing (11 ), wherein said at least one bent conduit arrangement (12) comprises at least a first conduit (13) and a second conduit (14) arranged in a bent pattern extending in the direction of the bent conduit arrangement (12) parallel to the flow of air, wherein the first conduit (13) is arranged interleaved with the second conduit (14), wherein the bent pattern comprises bent section portions (12a) and straight portions (12b), the straight portions (12b) being arranged horizontally and in a first direction relative the flow of air.

Description

TECHNICAL FIELD The present invention relates to a battery device for a ventilations system and preferably a ventilation system in a large scale kitchen, and in particular to a battery device in a ventilation system, preferably a ventilation system in a large scale kitchen.

BACKGROUND Most ventilation systems in newer residential and office buildings that contain both exhaust air and supply air deploy energy recycling equipment. The general aim is to extract the energy from the Warm exhaust air and, via a heat exchanger device, transfer the energy into the cold supply air to pre-warm it, using recycled energy. Such a part can for example be a cross-stream air-to-air exchanger configured to transfer the inherent energy in the exhaust air to the supply air utilizing metal flanges, or a rotating air-to-air exchanger where the energy exchange is achieved by means of a rotating disc transferring the energy from the exhaust air to the supply air.

Such a part can also be a battery device which is configured to extract inherent energy in the exhaust air mainly utilizing the difference in temperature between the exhaust air and a fluid inside the battery and subsequently reversing the process in the supply air to heat the cool supply air.

Particularly during the cold winter months, regardless of which recycling technology is deployed, this recycled energy cannot raise the temperature of the supply air all the way to the desired temperature needed to keep a comfortable ambient temperature indoors - Therefore, the supply air will be incrementally heated with an extra heating battery, placed downstream of the recycling battery. This battery is connected to the building°s heating system, utilizing whatever means of heating that is deployed, for example district heating, gas or electricity to infuse the supply air with the incremental energy needed to achieve the desired temperature.

To protect the technical equipment designed to extract the energy from the Warm exhaust air, the flowing exhaust air is always filtered before it is led into the energy recycling equipment. Such filtration norrnally consists of bag filters, designed to capture particles that otherwise might get stuck on the recycling equipment and there, as a first detrimental effect, deteriorate the efficiency of the energy exchange. As a second detrimental effect, the particles can start blocking the path of the eXhaust air, resulting in an increased resistance, Which means the fans Will have to Work harder to eXtract the required air volumes from the building, thus increasing the energy bill. In the eXtreme case, the particles building up might eventually block up the equipment to an extent that the air floW cannot be maintained, resulting in a seriously deteriorated indoor air quality.

As one aim is to reduce the energy needed, by recycling the energy (heat or cold), it is a serious draWback if the energy needed to drive the air floW through the recycling equipment Would substantially detract from the total net amount of energy recycled by the system.

In ventilation systems for restaurants, bakeries or similar establishments different types of air borne particles, formed during cooking, baking or other activities, create severe issues for the technical equipment designed to eXtract the energy from the Warm eXhaust air. EXamples of such particles can be grease, zoot or dust.

The problem With these particles is that they Will - very quickly - clog up the traditional bag filters used to protect the recycling equipment in residential and office building ventilation. Traditionally, such recycling equipment is thus not useful in ventilation systems that handles airfloW containing such contaminants. The ventilation industry has therefore during many years tested other filtration technologies designed specifically to eXtract or remove grease and zoot from the eXhaust air in restaurant and bakery ventilation, leading to increased costs.

There is also a problem in the prior art in that manufacturing, assembling and mounting traditional systems having both a filter and a battery unit requires time and leads to high costs.

There are numerous patents pertaining to this traditional approach of trying to create a robust solution specifically for energy recycling in ventilation systems for restaurants, bakeries and similar types of establishments. These are all aimed at as a first step to filter and clean the eXhaust air to capture or remove the grease and as a second step to subsequently lead the filtered and cleaned and supposedly grease-free exhaust air through energy recycling devices designed for residential and office type Ventilation systems. One known prior art is described in for example EP SUMMARY An objective has been to find a new technical solution that would enable to extract the inherent energy in exhaust air (for example from restaurant, bakery and similar ventilation systems) robustly, over time, even when handling air carrying lots of contaminants.

It should be noted that the teachings herein may be applied to both heating systems as well as cooling systems, where heating energy is extracted and recycled in heating systems and cooling energy is extracted and recycled in cooling systems.

An objective has been to find a new technical solution that would enable to extract the inherent energy also in air (for example from restaurant, bakery and similar ventilation systems) without having to deploy and try to protect energy recycling units that are designed for other types of ventilation systems, i.e. energy recycling units for residential and office ventilation, which cannot survive in the extreme environment. The new technical solution is a totally new type of energy extraction unit, specifically designed to be able to survive in the aggressive environment occurring in ventilation systems in restaurants, bakeries and similar operations represent, without any need for pre-filtration of the air by means of a separate air cleaning technology and with the inherent, specifically designed-in ability to manage the air borne particles that would clog up the traditional energy recyclers.

These objectives are achieved by a technique defined in the appended independent and dependent claims and where certain embodiments are being set forth in the related dependent claims.

In a first aspect, there is provided a battery device for a ventilation system, arranged to receive a flow of air, configured to extract energy from the flow of air, said battery device comprises: a housing arranged to receive said flow of air through a first end and at least one bent conduit arrangement arranged inside said housing to extend in a direction from the first end of the housing to a second end of the housing, whereby said floW of air Will pass along the bent conduit arrangement When said floW of air is received by said housing, Wherein said at least one bent conduit arrangement comprises at least a first conduit and a second conduit arranged in a bent pattern extending in the direction of the bent conduit arrangement parallel to the floW of air or tilted at a small angle relative the direction of the floW of air, Wherein the first conduit is arranged interleaved With the second conduit, Wherein the bent pattern comprises bent sections and straight sections, the straight sections being arranged horizontally and in a first direction relative the floW of air :as toa-tr For the context of the teachings herein, horizontal should be understood to be in the range of 2 to -2 degrees seen in the direction of floW of air.

As the bent conduit arrangements are arranged parallel to the floW of air, the bent sections Will also be arranged substantially horizontal. This insightful arrangement of the bent conduits being arranged horizontally or slightly tilted enables for the fluid to be transported through the conduits at a minimum or at least reduced pressure drop. Furthermore, interleaving the conduits enables a greater number of conduits to be used (and at greater length) than prior art systems using the same amount of energy to pump the fluid. This provides for an increased heat exchange (as the heat exchange surface is increased substantially compared to prior art systems using the same amount of energy) making the battery device according to the teachings herein highly energy efficient, especially compared to prior art systems. battery device comprises at least two bent conduit arrangements Wherein a first bent conduit arrangement is arranged parallel to a second bent conduit arrangement at a vertical distance. The floW of air is thus enabled to pass through the battery device substantially unhindered, While still providing a sufficient surface for heat exchange between the floW of air and the fluid due to the insightful arrangement of the bent conduit arrangements. Furthermore, most, if not all, of the (unWanted) particles in the floW of air Will thus also pass through the battery device Without colliding With the intemal structure of the battery device and clogging up the battery device. The battery device according to herein thus does not require any pre- filtering as in prior art systems.

In a second aspect there is provided a self-cleaning battery device, Wherein the at least one conduit has an outer surface, the conduit being configured to receive a fluid, Wherein the conduit is configured to have a first temperature and a second temperature, Wherein When the conduit has the first temperature, condensation and a particle layer of pollutants is formed on the outer surface of the conduit, and Wherein When the conduit has the second temperature the condensation freezes and subsequently cracks the particle layer such that the particle layer is detached from the conduit, thereby self- cleaning the battery device.

In a third aspect there is provided a method for self-cleaning of a battery device, Wherein the method comprises: causing the at least one conduit to assume a first temperature, Whereby condensation and a particle layer of pollutants is formed on the outer surface of the at least one conduit; and causing the conduits to assume a second temperature, Whereby the condensation and the particle layer freezes and subsequently cracks such that the particle layer is detached from the at least one conduit.

The battery device according to herein is arranged to be highly efficient providing for a minimum in pressure drop both in the fluid and in the eXhaust air While providing a maximum heat exchange. The battery device according to herein also does not need any pre-filtering.

The battery device is also easy to manufacture and assemble and enables for operation using a minimum of energy.

One aspect of the invention is to utilize a battery device as herein in a ventilation system (as herein) as an energy battery to facilitate additional recycling of the energy in the ventilation system, thus reducing the amount of energy having to be purchased from a utility company and also eliminate or at least reduce the need for any pre-filterin g .

The arrangements according to herein provide for a simple and elegant solution to several problems that have been prevalent in the industry for several years, even decades.

Other embodiments are disclosed in the detailed description and in the attached claims and other benefits are also disclosed in the description herein.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described in the following, reference being made to the appended drawings which illustrate non-limiting examples of how the inventive concept can be reduced into practice.

Fig. 1 is a schematic view of a Ventilation system according to an embodiment of the invention, Fig. 2 is a schematic view from above of a bent conduit arrangement according to one embodiment of the teachings herein to be used in a battery device according to an embodiment of the invention used in the Ventilation system in Fig. 1, Fig. 3A is a schematic view of a bent conduit arrangement according to one embodiment of the teachings herein, Fig. 3B is a schematic view of a bent conduit arrangement according to one embodiment of the teachings herein, Fig. 4A is a schematic view of an arrangement of bent conduit arrangements according to one embodiment of the teachings herein, Fig. 4B is a schematic view of an arrangement of bent conduit arrangements according to one embodiment of the teachings herein, Fig. 5 is a schematic view of an arrangement of bent conduit arrangements according to one embodiment of the teachings herein, Fig. 6 is a schematic side view of a bent conduit arrangement according to one embodiment of the teachings herein, Fig. 7 is a schematic view of an assembly of supports to be used with bent conduit arrangements according to one embodiment of the teachings herein, Fig. 8 is a schematic view of how a plurality of supports can be used in a bent conduit arrangement according to one embodiment of the teachings herein, Fig. 9 is a schematic view of a Ventilation system according to an embodiment of the invention, Figures 10A, 10B, 10C and 10D each show a schematic view of a conduit wall and a layer of pollutants and how they are affected according to the present invention, Figure 11 showing a flowchart for a general method of the teachings according to the present invention, and Figure 12 is a schematic view of an altemative battery device according to herein.

DETAILED DESCRIPTION OF EMBODIMENTS With reference to the drawings, figure 1 is a schematic side-view of a ventilations system 1 with a duct 2 and a battery device 10 arranged along the duct 2 so that the duct 2 may lead eXhaust air through the battery device 10. The ventilation system 1 as such can be any known type of ventilation system and is not lirniting the features of the battery device 10. The ventilation system 1 can even be located in an environment where eXhaust air contains unwanted particles such as grease, zoot, dust or other types of particles which needs to be effectively managed. Such an environment can for example be a large scale restaurant kitchen, a bakery or any other where unwanted particles are created during use.

These types of particles may be of different sizes and shapes. A typical range of particle sizes for more than 95% of the sample mass of a troublesome pollutant - grease - is from 2 um up to 25 um.

The battery device 10 is designed and arranged to receive a flow F of air, such as eXhaust air possibly containing unwanted particles (not shown in figure 1), flowing through the duct 2 of the ventilation system 1. The flow F of air is achieved and/or enforced by a fan unit 3. The fan unit may be located towards the front-end and/or the back-end of the ventilation duct 2. The fan unit 3 can be any type of fan unit used in ventilation systems today.

The battery device 10 presented below is enabled to eXtract energy from the flow of eXhaust air due to temperature differences between the flow of air and the conduits of the battery device 10 that the air passes through. This is explained in more detail below. The battery device 10 presented below is also able to keep the battery device clean enough for efficient operation in contaminated eXhaust air, without the need for any pre-filtration. That is, the battery device according to the present invention is efficient and robust enough to operate even when no pre-filtration is provided, as the structure of the battery device 10 according to herein is not prone to clogging. The battery device according to herein is also able to self-clean any particles that do adhere to the metal surfaces of the battery device.

The eXtracted energy may then be re-distributed into the energy system of a building, for example in the building in which the ventilation system is installed, utilizing the eXtracted energy where it is needed and/or beneficial. The eXtracted energy may also or alternatively be redistributed to other systems as needed.

In order to achieve the above purposes, the battery device 10 includes a plurality of conduits 13,14 through which the exhaust air flows. The conduits 13,14 are arranged in horizontally arranged bent conduit arrangements Figure 2 shows a schematic top view of a battery device 10 according to the teachings herein. As can be seen, the battery device 10 comprises a bent conduit arrangement 12 comprising two conduits, a first conduit 13 and a second conduit 14. It should be noted that even though only one bent conduit arrangement 12 is shown in figure 2, this is purely for illustrative purposes, and a battery device 10 would comprise a plurality of bent conduit arrangements 12, as will be illustrated below. It should also be noted that even though the bent conduit arrangement 12 is eXemplified as having two conduits, a bent conduit arrangement may comprise three, four or even more conduits, as will also be illustrated below.

As can be seen in figure 2, the battery device is arranged to receive a flow of (exhaust) air, referenced “F°, through a first end 1 la, to guide the flow F over the bent conduit arrangement 12 and then out of the second end 11b of the battery device 10. The bent conduit arrangement eXtends in a direction substantially parallel to the flow of the air, and horizontally, comprising a plurality of straight sections 12b of conduit that are arranged substantially perpendicular to the flow of air, also horizontally.

The first conduit 13 and the second conduit 14 of the bent conduit arrangement 12 of figure 2 are interleaved so that they run substantially parallel in substantially the same horizontal plane (with reservations to manufacturing variations) back and forth across the flow F of air. This enables for a large surface of the conduits to interact with the flow of air using only a small volume for the battery device Compared to using a single conduit that is bent more times and allowed to run back and forth across the flow of air, the use of several conduits reduces the pressure drop in each conduit, thereby reducing the energy needed to pump a fluid through the conduits, thereby also reducing the energy consumption of the battery device The straight sections 12b are connected by bent sections 12a. In one embodiment, the straight sections 12b and the bent sections 12a are made of separate pieces that are to be joined.

In one embodiment, the straight sections 12b and the bent sections 12a of at 1east one conduit are formed by the same conduit, by the conduit being bent or bent repeated1y. This has the benefit of reducing the time and cost for manufacturing and assemb1ing the battery device.

In one embodiment, the straight sections 12b and the bent sections 12a of at 1east one conduit are formed by the one or more conduits, by the conduits being bent or bent repeated1y and joined together.

Using bent conduits a1so has the benefit in simp1ifying the distribution and co11ection of coo1ing fluids. As the conduits are bent, on1y one point of distributing and one point for co11ecting are needed, Which reduces the cost for manufacturing the co11ection and distribution conduits as We11 as assemb1ing the battery device 10. As Wi11 be c1ear from the be1oW, using the same co11ection and distribution conduits for severa1 bent conduit arrangements a1so reduces the cost for manufacturing and assemb1ing the battery device.

As the conduits 13, 14 are arranged horizonta11y, the bent sections Wi11 a1so be arranged horizonta11y. This ensures that no air (or other gas) bubb1es are captured in the bends, Which ensures that the Work required for the pump that circu1ates the coo1ing fluid is maintained at an acceptab1e 1eve1 and that the pressure drop in the conduits is kept 1oW.

In order for the first and second conduits to be inter1eaved, the bent sections 12a are made up of bent sections 13a, 13b, 14a, 14b for the first and the second conduits that are repeated a1ternating1y. In the example of figure 2, the first conduit 13 comprises a first bent section 13a and a second bent section 13b, Wherein the first bent section 13a is arranged on one side of the bent conduit arrangement 12, and the second bent section 13b is arranged on the opposite side of the bent conduit arrangement 12. Likewise, the second conduit 14 comprises a first bent section 14a and a second bent section 14b, wherein the first bent section 14a is arranged on one side of the bent conduit arrangement 12, and the second bent section 14b is arranged on the opposite side of the bent conduit arrangement 12. The first and the second bent sections are repeated altematingly across the length of the conduit and the bent conduit arrangement 12. In the example of figure 2, the first bent section 13a of the first conduit 13 matches the first bent section 14a of the second conduit 14 in such a manner that the first conduit 13 runs parallel - or substantially equidistant - to the second conduit 14 also through the bent section 12a.

In the example of figure 2, the first bent section 13a of the first conduit 13 equals the second bent section 14b of the second conduit 14, and the first bent section 14a of the second conduit 14 equals the second bent section 13b of the first conduit In one embodiment a bent section may be a radially curved portion of conduit.

In one embodiment a bent section may be a bent portion of conduit.

In one embodiment a bent section may be a bent portion followed by a straight portion followed by another bent portion.

In one embodiment, the bent sections are arranged to be substantially 180 degrees, seen from an inlet of the bent section to an outlet of the bent section. In one embodiment, the bent sections are arranged to be in the range 178-182 degrees. In one embodiment, the bent sections are arranged to be in the range 175-185 degrees. In one embodiment, the bent sections are arranged to be in the range 170-190 degrees. In one embodiment, the bent sections are arranged to be in the range 160-200 degrees. The greater the angle of a bent section, the area of the straight sections can be housed in a given area/volume. The smaller the angle, the less drop in pressure of the fluid. The angles possible are also dependent on the length of the straight sections and the distance between the straight sections. A compromise may therefore be made and the inventors have found that an angle of 180 degrees provide for a good compromise that is also easy to install.

For an angle differing from 180 degrees, the straight sections may not be truly parallel, but will be discussed herein as being parallel in the meaning that they run in the same horizontal plane. ll The bent sections may be continuous (or Smooth). The bent sections may also or altematively be discontinuous. In one such embodiment, the bent section is stepwise discontinuous using substantially straight portions. In one alternative or additional such embodiment, the bent section is stepwise discontinuous using substantially straight portions connected by smooth bends.

A bent section thus comprises at least one bent portion and possibly one or more straight portions. A straight portion, need not be strictly straight, but can be a portion having a curvature with a large radius.

In one embodiment, the bent sections are arranged to be semi-oval.

In one embodiment, the bent sections are arranged to be sen1i-circular.

In one embodiment, the bent sections are arranged to be U-shaped.

In one embodiment, each bent conduit arrangement 12 comprises more than 5 bent sections for each conduit 13, 14. In one such embodiment, each bent conduit arrangement 12 comprises more than 9 bent sections for each conduit 13, 14. In one such embodiment, each bent conduit arrangement 12 comprises more than 15 bent sections for each conduit 13, 14. In one such embodiment, each bent conduit arrangement 12 comprises more than 25 bent sections for each conduit 13, 14. In one such embodiment, each bent conduit arrangement 12 comprises more than 35 bent sections for each conduit 13, A conduit may have bent sections of the same type or of varying or different types.

As the number of bent sections for a conduit grows, the surface for heat exchange also grows. However, the pressure drop for the fluid in the conduit will also grow. Therefore, as the inventors have realized, it is better to use interleaved conduits instead of increasing the length (number of bent sections) of a conduit, as the surface for heat exchange will remain the same, while not increasing the pressure drop for the fluid.

In order for the conduits to be interleaved, the first and second bent sections for the first conduit are not of the same radius or extent in the case of a non-radially curved bent section, one bent section being smaller than the other to enable the interleaving of conduits 13, 14, by one bent section partially encompassing the other bent section.In one embodiment, a bent section of a first conduit is arranged to match a corresponding bent section of the second conduit by the conduits being at an equal distance (equidistant) to each other through the bent section.

In one embodiment, a bent section of a first conduit is arranged to match a corresponding bent section of the second conduit by the outer conduit being arranged to accommodate or partially enclose the inner conduit through the bent section.

In one embodiment, the bending radius of the smaller bent section is equal to 1.5 to 2.5 times the diameter of the conduit. In one embodiment, the bending radius of the smaller bent section is equal to 1.75 to 2.25 times the diameter of the conduit In one embodiment, the bending radius of the smaller bent section is equal to or larger than twice the diameter of the conduit.

This ensures that any fluid that is transported through the conduit will travel unhindered and decreases the turbulence in the conduit.

In one embodiment, the bent section of the smaller bent section is made utilizing bending machines based on a technique not deforming the inner radius of the bent section, for example booster functionality. In such an embodiment, the bent section radius may be smaller than twice the diameter of the conduit.

The pairs of conduits (i.e. the first and the second conduits) making up a straight section 12b is arranged at a section distance (indicated D2 in figure 2) from another pair of conduits, i.e. the next section. By placing the straight sections at a distance from one another enables the passing air to enter this void so that any turbulence caused by the conduits may evolve and also increases the exposed surface between the air in the air flow F and the conduits 13, 14, which increases the heat exchange between the fluid in the conduits and the air.

In one embodiment the section distance is 14 mm. In one embodiment the section distance is in the range 12 to 16 mm. In one embodiment the section distance is in the range 10 to 20 mm. In one embodiment the section distance is in the range 5 to 30 mm.

In one embodiment the section distance is dependent on the diameter of the conduit. In one such embodiment the section distance is in the range 2-5 times the diameter of the conduit. In one such embodiment the section distance is in the range 2-times the diameter of the conduit. In one such embodiment the section distance is 2 times the diameter of the conduit.

Along the straight sections, the first and second conduits 13, 14 are arranged at conduit distance (indicated D1 in figure 2) from one another. For straight sections not running parallel, the distance is an average or a mid-point distance. By keeping the conduit distance low, more conduits may be housed in the same area, thus increasing the use of space making the battery device smaller for the same number of straight sections and conduit surface exposed to the flow of air. The conduit distance D1 is therefore smaller than or equal to the section distance D In one embodiment the conduit distance is 14 mm. In one embodiment the conduit distance is in the range 12 to 16 mm. In one embodiment the conduit distance is in the range 10 to 20 mm. In one embodiment the conduit distance is in the range 5 to 30 mm.

In one embodiment the conduit distance is dependent on the diameter of the conduit. In one such embodiment the conduit distance is in the range 2-5 times the diameter of the conduit. In one such embodiment the conduit distance is in the range 2-3 times the diameter of the conduit. In one such embodiment the conduit distance is 2 times the diameter of the conduit.

Figures 3A and 3B each show a schematic top-view of an altemative embodiment of a bent conduit arrangement 12 as per the teachings herein. As mentioned above, a bent conduit arrangement 12 may comprise more than two conduits, and figure 3A shows an example where a bent conduit arrangement 12 comprises a first conduit 13, a second conduit 14 and a third conduit 15. As can be seen, the conduits are approximately equidistant in the bent sections 12a and parallel in the straight sections 12b. The third conduit 15 is arranged between the first conduit 13 and the second conduit 14. The third conduit 15 is, in one embodiment, arranged with a bent section that is repeated over the third conduit”s extension in the bent conduit arrangement Figure 3B shows an example where a bent conduit arrangement 12 comprises a first conduit 13, a second conduit 14, a third conduit 15 and a fourth conduit 16. As can be seen, the conduits are approximately equidistant in the bent sections 12a and parallelin the straight sections 12b. As can be seen, the fourth conduit 16 is arranged in between the first conduit 13 and the second 14 adjacent the third conduit In one embodiment, the third conduit 15 is arranged bent uti1izing a first 15a and a second 15b bent section, the fourth conduit 16 is arranged bent uti1izing a first 16a and a second 16b bent section, wherein the first bent section 15a of the third conduit 15 corresponds to the first bent section 16a of the fourth conduit 16 and the second bent section 15b of the third conduit 15 corresponds to the second bent section 16b of the fourth conduit In one embodiment, two (or more) bent conduit arrangements may be arranged nest1ed or inter1eaved as an alternative or in addition to, having more conduits in the bent conduit arrangement. In such an embodiment, the section distance wi11 then vary between sections to accommodate a section from the nest1ed bent conduit arrangement.

As mentioned above, a battery device 10 according to the teachings herein comprises more than one bent conduit arrangement 12, and figure 4A shows a schematic top-view of a battery device 10 comprising a first bent conduit arrangement 12-1 and a second bent conduit arrangement 12-2. For i11ustrative purposes on1y two bent conduit arrangements are shown in figure 4A. As can be seen the first bent conduit arrangement 12-1 is arranged on top of the second bent conduit arrangement 12-2. By stacking the bent conduit arrangements on top of one another, severa1 bent conduit arrangements 12 may be housed in the same battery device In one embodiment, the first bent conduit arrangement 12-1 is arranged straight on top of the second bent conduit arrangement 12-2. This has the benefit of making the overa11 size of the battery device, and the size of the distribution and co11ection conduits sma In one embodiment, the first bent conduit arrangement 12-1 is arranged on top of the second bent conduit arrangement 12-2, but offset in the direction of the flow of air. In one embodiment, the first bent conduit arrangement 12-1 is offset the second bent conduit arrangement 12-2 by an offset distance (referenced D4 in figure 6). This has the benefit of reducing the turbu1ence created between the bent conduit arrangements when the flow of air is received, thereby a11owing for a minimized pressure drop.

In one embodiment the offset distance is 14 mm. In one embodiment the offset distance is in the range 12 to 16 mm. In one embodiment the offset distance is in the range 10 to 20 mm. In one embodiment the offset distance is in the range 5 to 30 mm.

In one embodiment the offset distance is dependent on the diameter of the conduit. In one such embodiment the offset distance is in the range 2-5 times the diameter of the conduit. In one such embodiment the offset distance is in the range 2-3 times the diameter of the conduit. In one such embodiment the offset distance is 2 times the diameter of the conduit.

The first bent conduit arrangement 12-1 is arranged at a vertical distance D3 from the second bent conduit arrangement 12- In one embodiment, the Vertical distance D3 is 3 to 7 mm. In one embodiment, the vertica1 distance is 5 mm.

In one embodiment, the vertica1 distance D3 is proportiona1 to the diameter of the conduit. In one such embodiment, the vertica1 distance D3 is in the range 0.5 to 1 times the diameter of the conduit.

The vertica1 distance D3 is, in one embodiment, a minimum distance between the two bent conduit arrangements. Some conduits may be at a 1arger distance from one another, but not a sma11er.

The vertica1 distance D3 is, in one embodiment, an average distance between the two bent conduit arrangements.

By ensuring a (minimum) Vertical distance between the bent conduit arrangements, the flow of air is provided with passages to flow through, thereby reducing the pressure drop and/or the power needed to drive the flow of air through the battery device and the pressure drop of the air flow can be kept at a 1ow and acceptab1e 1eve1. The actua1 minimum distance needed depends on the air flow and the required minimum pressure drop.

Figure 4B shows a side-view of a conduit arrangement 12 according to the teachings herein comprising at 1east a first and a second bent conduit arrangement 12-1, 12-2. As can be seen the bent conduit arrangements may be arranged ti1ted re1ative the flow of air. In one embodiment, this is achieved by arranging a front portion of the bent conduit arrangement at a higher position, than a rear portion of the conduit arrangement.Figure 4B illustrates a tilt angle gamma, which is greatly exaggerated for illustrative purposes. The tilt angle is, in one embodiment, in the range 5 to -5 degrees relative the direction of the flow of air, as indicated by the dashed line in figure 4B. The tilt angle is, in one embodiment, in the range 1 to -5 degrees. The tilt angle is, in one embodiment, in the range 1 to -2 degrees. By arranging the conduit arrangement 12 at a tilt angle, where the front portion is higher than the rear portion, it will be easier to transport any gas bubbles out of the system. As the tilt angle is relatively small, the flow of air will still be allowed to flow unhindered through the battery device The tilt angle is, in one embodiment, substantially 0 degrees (with reservations to manufacturing variations).

Figure 5 shows a schematic side-view of an arrangement of bent conduit arrangements 12 comprising a realistic number of bent conduit arrangements 12. In the example of figure 5, there are forty (40) bent conduit arrangements 12 all stacked and altematingly offset one another.

Figure 6 shows a schematic side-view of a cross-sectional cut-out, showing the openings of the conduits 13, 14 of several bent conduit arrangements 12-1-12-4. In figure 6, the various distances D1-D4 are shown, and in the example of figure 6, the distances D1-D3 are substantially equal and the offset distance D4 approximately equaling half the other distances (D4=D1/2).

In one embodiment a battery device 10 according to herein comprises 30 to 80 bent conduit arrangements, each comprising 10 to 20 bent sections.

Utilizing a battery device as per herein, has several benefits, and provides an improved heat exchange. This improved heat exchange is in part due to the arrangement of the bent conduits and the relationship between the distances between the conduits. The heat exchange in a battery device as per herein has been found to be so efficient that the actual material of the conduits is of less importance. However, in one embodiment, the conduit is made of brass or a brass alloy. In one embodiment, the conduit is made of an aluminum alloy. In one embodiment, the conduit is made of a copper or copper alloy. ln one embodiment, the conduit is made of stainless steel. In one embodiment, the conduit is made of plastic.In one embodiment, the bent conduit arrangements are kept in place by their connections to the distribution 19 and collection conduits bent conduit arrangements 12 are kept at the minimum distance from one another also by supports 17 being arranged between at least some of the bent conduit arrangements 12. This has the benefit that the conduits may be made of thinner material and especially that the connections to the distribution and collection conduits may be made less robust.

Figure 7 shows a schematic side view of two supports 17-1 and 17-2. Each support is arranged with a first (upper) side 17A and a second (lower) side 17B. At least one side is arranged with at least one cut-out 17C, that may be circular, semi-circular, rectangular, U-shaped or otherwise shaped and sized to receive a conduit 13, 14 (or 15, 16 not shown in figure 7). It should be noted that the length of the supports may vary as per the length of the bent conduit arrangement 12, and the length in figure 7 is chosen for illustrative purposes and is arranged to hold 4 to 5 straight sections.

In one embodiment, the cut-outs 17C are arranged in groups, where the number of cut-outs in the group correspond to the number of conduits in the bent conduit arrangement. In the example shown in figure 7, there are two cutouts 17C1 and 17C2 in each group.

The distance between each cutout 17C in a group substantially corresponds (within variances due to machining and to allow for tolerances) to the distance between conduits in a straight section; Dl. The distance between each cutout group substantially corresponds (within variances due to machining and to allow for tolerances) to the distance between straight sections; D The distance between cutouts 17C in a first side 17A and the cutouts in a second side 17B of a support 17 group substantially corresponds (within variances due to machining and to allow for tolerances) to the distance between bent conduit arrangements; D In one embodiment, the cutouts 17C are sized and shaped to receive each a conduit 13, 14 of each straight section. In figure 7, this is indicated by cutouts 17C1, 17C2. This enables a more stable arrangement, preventing or reducing any vibration in the conduits.In one embodiment, the cutouts 17C are sized and shaped to receive a conduit section, i.e. the first, second and so on conduit of each straight section. In figure 7, this is indicated by cutout 17C”. This enables a lighter support (saving on materials cost) and an easier mounting.

As is disclosed with relation to the conduit distance D1 and the section distance D2 above, the cutout distances may also be equal.

When mounting the bent conduit arrangements 12and the supports 17, the conduits 13,14 of a first bent conduit arrangement 12 (not shown in figure 7) are mounted or placed within the cutouts 17C (such as 17C1, 17C2, 17C°) of a first (upper) side 17A of a first (lower) support 17-1, as indicated by the arrows in figure 7. A second (upper) support 17-2 is then placed on top so that the cutouts 17C of the second (lower) side 17B of the second (upper) support 17-2 receives the conduits 13, 14, as indicated by the arrows in figure 7. As can be seen in figure 7, the sections between cutouts may overlap, in one embodiment, when the supports are mounted.

In one embodiment, there is arranged a hole 17D in at least one section between two cutouts 17C in the first support 17-1. In one such embodiment, there is arranged a corresponding hole 17D” in a corresponding section between two cutouts 17C in the second support 17-2. In an altemative or additional such embodiment, there is arranged a corresponding pin 17E in a corresponding section between two cutouts 17C in the second support 17- By aligning a hole 17D with a corresponding hole 17D, the two supports 17-1 and 17-2 may be attached to one another by inserting a screw, pin, bolt or other attachment means (not shown) through the holes 17D and 17D”. Altematively or additionally, the pin 17E is inserted into and through the hole 17D to attach the two supports.

By attaching the supports to one another, a more stable arrangement is provided.

In one embodiment, as shown in figure 7, the first side 17A and the second side 17B of a support 17 are arranged at a support angle A to one another. This enables an easier assembly or mounting as the attachment means may be inserted from above at anangle, instead of from the side, which at mounting is inside the bent conduit arrangement In one embodiment, the cutouts 17C are rectangular. In one embodiment, the cutouts 17C are U-shaped. In one embodiment, the cutouts 17C are semi-circular.

Figure 8 shows a schematic view of how a plurality of supports 17-1, 17-2, 17- 3 may be mounted with relation to one another, where the supports may be joined at an angle, as indicated by the dashed arrows.

In one embodiment, there may be a base support 17-0 at the lower or upper end of the arrangement for simplifying the mounting as if the support is leaned at an angle to a supporting structure it will not stand by itself until it is joined to another support. In one embodiment, such base support 17-0 is part of, comprised in or joined to the housing 11. In one embodiment, the base support 17-0 is arranged so that the upper side 17A is arranged with cutouts 17C (and the lower is not, apart from cutouts for reducing the weight or receiving other structures). In one embodiment, the base support 17-0 is arranged so that the upper side 17A is arranged at a second angle B relative the lower part, where the second angle B substantially equals half the angle A plus 90 degrees.

Returning to figure 1, the battery device 10 is, in one embodiment, arranged in a Ventilation system 1. However, it should be noted that the battery device may be arranged in any system, where energy is to be eXtracted from an air (or other gas) flow.

In operation, the battery device 10 further comprises a fluid that the battery device is arranged to receive, such as a refrigerant. The fluid is to be transported through the conduits 13, 14. In one embodiment, the fluid is brine. The fluid is, in one embodiment, configured to cool the conduits 13, 14 which in tum will cool the surrounding eXhaust air. It should be noted that the fluid may alternatively be used to heat the conduits. A common temperature of such a flow F of eXhaust air is between 20°C and 32°C and a common temperature of the transported fluid is between -10°C and 20°C which means that a temperature drop of between 4°C and 18°C of the eXhaust air can be achieved. Thus, the (cooling) fluid and the arrangement of conduits 13, 14 are configured to eXtract energy from the flow F of exhaust air by cooling the eXhaust air, and also by eXtracting the energy released as parts of the water content in the eXhaust air condensates.

In prior art battery devices, a pre-filtration is required as the battery devices will otherwise clog up too quickly to operate efficiently.

The battery device 10 of the present invention is, however, constructed in such a manner that no pre-filtering is needed. The design of the battery device disclosed herein minin1izes the pressure drop of the flow of air, and thus allows the flow of air to pass (relatively) unhindered.

This is enabled by the bent section arrangement°s aerodynamic qualities which allows for the flow of air to pass (relatively) unhindered through the battery device thereby allowing the pollution particles (e.g. grease, soot, moisture, etc.) to also pass through the battery device, without colliding with and adhering to the internal structure (bent section arrangements and so on) of the battery device 10, preventing or at least reducing the risk of the battery device clogging up.

The battery device 10 is thus capable of operating in contarninated air without the need for pre-filtering.

Returning to the battery device 10 the cooling fluid is arranged to run in a closed loop between the conduits 13, 14 of the battery device 10 and an optional thereto connected pump by means of two pipes. The pump can be replaced by for example a heat eXchanger, a heat pump or any other suitable device, such as the heating system 4,5 discussed below, but for now will be referred to as a pump. The pump feeds the cooling fluid which has been cooled to the right temperature. A preferred temperature of the cooling fluid when entering the battery device 10 is between -10°C and 20°C. As the cooling fluid has passed through the conduits 13, 14 of the battery device 10 and cooled the conduits 13, 14, the cooling fluid returning now has a higher temperature. The cooling fluid is, within the closed loop, again cooled to the right temperature by any suitable device before returning to the battery device 10 and the conduits 13, 14. The difference in temperature between the cooling fluid and the retuming cooling fluid can be between 4°C and 18°C. The eXtracted energy from the flowing eXhaust air can be used to reduce the energy consumption of the overall system, for example, heat the building or room in which the ventilation system 1 operates. It should also be noted, as discussed above, that the teachings herein may equally well be applied in a cooling system, where energy is eXtracted and reused for cooling.Figure 9 shows a schematic view of a system 1, where a battery device 10 in a ventilation system is used as a battery device for heat exchange system 4, 5. It should be noted that many variations are possible for connecting the battery device of the present invention with a heat exchange system and figure 9 only shows one example. In one example, the heat exchange system is a heating system, where energy is extracted and reused for heating. It should also be noted, as discussed above, that the teachings herein may equally well be applied in a cooling system, where energy is extracted and reused for cooling.

The heat exchange system 4, 5 generally comprises a first unit 4 and a second unit 5. In one embodiment, the first unit 4 is a pump arranged to receive a fluid from the battery device 10 through conduit 7 and transport the fluid to the second unit 5 through conduit 8. In such an embodiment the fluid of the battery device is allowed to undergo heat exchange (HE) with a medium of the heat exchange system, for example for heating or cooling supply air thereby recycling or reusing the energy extracted by the battery device. The fluid is then returned to the battery device through conduits 9 and In one embodiment the first unit is a heat pump arranged to receive and return a fluid from the battery device 10 through conduits 6 and 7 and allow the fluid received from the battery device 10 to undergo heat exchange (HE) with a fluid of the heat exchange system which is transported between the first unit 4 and the second unit 5 through conduits 8 and 9. In such an embodiment the fluid of the heat exchange system is then allowed to undergo heat exchange with a medium of the heat exchange system, for example for heating or cooling supply air thereby recycling or reusing the energy extracted by the battery device.

Such heat exchange systems 4, 5 are known and require no further explanation, and it should be noted that since they are so well-known many details and variations have been left out for reasons of conciseness. For example, in the embodiment where the first unit 4 is a pump, the pump of the heat exchange system may be implemented or replaced by a pump 21 of the battery device 10, the two systems sharing a pump.

Returning to figure 2, the battery device 10 further has a distribution conduit 19 arranged to receive the fluid (cooling fluid in the example of a heating system and heating fluid in the example of a cooling system) from the pump 21. As is indicated infigure 2 by the dashed box referenced 4,5, the fluid may also be pumped through an additional or external system 4,5 as discussed in relation to figure 9. The distribution conduit 19 is arranged to distribute the fluid to each one - or at least a plurality - of the conduits 13, 14 of a bent conduit arrangement 12. Further, the battery device 10 includes a collection conduit 20 arranged to receive the fluid after it has been transported through the conduits 13, 14 of a bent conduit arrangement 12 and return it to the pump 21, possibly via a heating system 4, In one embodiment the distribution conduit 19 is arranged to distribute the fluid to a plurality of bent conduit arrangements 12, and in one such embodiment the distribution conduit 19 is arranged to distribute the fluid to all of the bent conduit arrangements 12 of the battery device Similarly, in one embodiment the collection conduit 20 is arranged to collect the fluid from a plurality of bent conduit arrangements 12, and in one such embodiment the collection conduit 20 is arranged to collect the fluid from all of the bent conduit arrangements 12 of the battery device Such collective distribution and collection is made possible by the clever arrangement of bent conduit arrangements, enabling for a minimum pressure drop in the fluid. This also enables for a simplified manufacturing and installation.

In the example embodiment of figure 2, the distribution conduit 19 is arranged downstream of the flow of air F, and the collection conduit 20 is arranged upstream. This enables a more efficient heat exchange.

A water distribution device, here called a sprinkler device 23 may further be included in either the battery device 10 and/or in the ventilation system 1. Advantageously, the sprinkler device 23 can gather heated water from a chamber 22 for cleaning the battery device A shunting valve 29 may also be arranged in the ventilation system The battery device 10 as described above has many advantages. The battery device 10 may extract energy to be further used in a heating system, even without pre- filtering. In known ventilation systems these two features (the (heat) battery and the pre- filtering) are separate, using two different units to accomplish both filtering and energy extracting. This has not been beneficial since, for example, the amount of necessarycleaning and maintenance Work that needs to be done regularly is too extensive and not as efficient as With the battery device 10 presented above. Also, the pre-filtering brings about an unavoidable pressure drop in the floW of air, Which either leads to a lower efficiency of the heat exchange in the battery device, or must be compensated for, Which increases the power consumption of the system, also leading to a lower energy efficiency of the system. Often the unit enabling the energy extraction is not suited to handle unWanted particles such as grease, soot and similar Which, if they stick to the unit, also can affect the efficiency of it. Further, the filter units used today are not able to filter the floW of exhaust air such that the energy extracting unit is totally protected from the unWanted particles. By being robust enough to operate in unfiltered air, not only the efficiency of the ventilations system can be increased but also a less energy demanding fan unit can be used in the ventilation system. This is because the previously used energy extracting unit has created an obstacle in the course in Which the exhaust air floWs Which in turn demands a stronger fan to create the desired floW.

As there Will always be some degree of build-up of contaminants - even When using the clever arrangement of the bent conduit arrangements taught herein, the battery device 10 may also be arranged to be self-cleaning.

The battery device is configured to receive a floW of exhaust air containing pollutants, Wherein said battery device comprises at least one conduit With an outer surface, the conduit being configured to have a first temperature and a second temperature, Wherein When the conduit has the first temperature condensation and a particle layer of pollutants is formed on the outer surface of the conduit, and Wherein When the conduit has the second temperature the condensation and the particle layer freezes and subsequently cracks such that the particle layer is detached from the conduit.

This is advantageous since the battery device stays clean and no aggregation of grease particles and other pollutants Will clog the battery device. Since it is a self- cleaning process, no aid from a person, or addition of any extra media or chemicals, is needed and the cleaning is performed automatically. To crack the formed layer of pollutants With freezing, results in an efficient cleaning process Where no pollutant particles Will remain on the surfaces in the battery device, as Would be the issue if, forexample the chosen method for cleaning Would be to try to melt the adhered layer of pollutants off the conduits for example by hot water spray provided by the sprinkler device 23, or by running the fluid at a second (higher) temperature through the conduits.

In one embodiment, there is provided a ventilation system, wherein the at least one conduit is arranged to receive a fluid, which is arranged to assume a first and a second fluid temperature, wherein when the fluid assumes the first fluid temperature, the conduit will assume the first temperature, and when the fluid assumes the second fluid temperature, the conduit will assume the second temperature.

In one embodiment the conduit is caused to assume the second conduit temperature by causing the fluid to assume the second fluid temperature by regulating the temperature of the fluid.

In one embodiment the conduit is caused to assume the second conduit temperature by regulating the airflow.

In one embodiment, there is provided a self-cleaning battery device, wherein the second temperature is in a range between 0 to -60°C. Preferably, the second temperature is between -3 to -20°C, and more preferably between -8 to -12°C. These temperature intervals ensure that the formed ice layer cracks the layer of pollutants.

It should be noted, and as will be explained in the detailed description, that it is not the ice layer that cracks in its structure, but the ice layer cracks the particle layer thus forcing the particle layer to release its cohesion to or grip on the outer surface of the conduit.

In many situations the ventilation system 1 comprising the battery device 10 is located in an environment where exhaust air contains pollutants such as grease, soot, dust, grime or other types of particles, which need to be effectively managed. Such an environment may for example be a large scale restaurant kitchen, a bakery or any other environment where pollutants as described are air bome.

The battery device 10 is designed and arranged to receive a flow F of exhaust air which may contain pollutants flowing into the ventilation duct 2 and trough the battery device 10, where some of the pollutants may collide with the conduits 13, 14 of the battery device and a layer of pollutants is slowly built-up over time.

The battery device 10 according to herein, may however, be arranged to be se1f-c1eaning in a c1ever manner and the description be1ow and with reference to figures 10A-10D show how the battery device 10 is ab1e to remove po11utants from and c1ean itse1f, figure 10 being a series of schematic views of a conduit wa11 28 and a 1ayer of po11utants 25. First, the battery device 10 is arranged in the venti1ation system 1. In one embodiment, the conduits 13, 14 of the battery device 10 are then caused to assume a first conduit temperature TC1, or conduit coo1ing temperature TC In one embodiment causing the conduits to assume a first conduit temperature TC1 is accomp1ished by circu1ating the fluid having a first fluid temperature Tp1. Thus, the conduits 13, 14 assume a temperature TC1 c1ose to the temperature Tp1 of the fluid. Due to the first conduit temperature TC1, condensation wi11 form on the outer surface 28 of the conduits 13, As the fluid and the conduit wi11 have temperatures that- at 1east after an initia1 period after a temperature change has been effected - are substantia11y the same or at 1east corresponds to one another due to the heat transfer between the fluid and the conduit, it may be said that changing the temperature of the conduit corresponds to changing the temperature of the fluid and vice versa.

The flow of exhaust air F is provided to the battery device 10 and the air flows in between or next to the conduits 13, In one embodiment causing the conduits to assume a first conduit temperature TC1 is accomp1ished by the flow of eXhaust air, having a re1ative1y high temperature, being higher than the first conduit temperature TC1, which wi11 heat up the conduit (and a1so the fluid) and cause the conduit to assume the first conduit temperature which depends on the fluid temperature and the temperature in the flow of air.

Partic1es in the eXhaust air flow F wi11 co11ide with and adhere to the outer surfaces 28 of the conduits 13, 14. A 1ayer of po11utants 25 are thus formed on the surfaces To remove the po11utant1ayer 25, i.e. to c1ean the battery device 10 by a c1eaning process, the fluid is caused to assume a second fluid temperature Tpg, or freeze temperature. The second temperature TF; is 1ower than the first temperature Tp1. Thiscauses the conduits 13, 14 to assume a second conduit temperature TC; Which corresponds substantially to the second fluid temperature Tpg.

In one embodiment the fluid is caused to assume the second fluid temperature TF; (and thereby Will the conduit be caused to assume the second conduit temperature Tçg) by actively changing or regulating the temperature of the fluid, such as by cooling the fluid or by replacing the fluid. In such an embodiment, the fluid is caused to assume the first fluid temperature Tp1by actively changing or regulating the temperature of the fluid, such as by heating the fluid or by replacing the fluid.

In one embodiment the fluid is caused to assume the second fluid temperature TF; by causing the conduit to assume the second conduit temperature Tçg, thereby cooling the fluid, by adapting the floW of air F. As the inventors have realized, the floW of air has a heating effect on the conduits, and the floW of air can thus be used to regulate the temperature of the conduit 13, 14 causing the conduit to assume different temperatures, possibly Without changing the fluid in other manners, by simply adapting the floW of air.

It should be noted that the adaptation of air may be in addition to or as an altemative to adapting or regulating the fluid.

In one embodiment the floW of air is adapted by reducing the floW of air.

In one embodiment the floW of air is adapted by halting the floW of air.

In one embodiment the floW of air is adapted by shunting in cool air in the floW of air. The cool air may be shunted in through a shunting Valve 29. The cool air may be outdoor air in Which case no additional cooling Will be necessary, thereby saving further on energy consumption.

In one embodiment the floW of air is adapted While circulating the fluid. The fluid Will thus not be heated as much any longer by the floW of air, and the conduit Will assume the second temperature being lower than the first temperature.

As simply adapting the floW of air, especially by reducing, halting or shunting in outside air, does not require any energy to perform, but actually reduces the power consumption, the overall power consumption of the ventilation system is reduced and the cleaning process is highly efficient and environmentally friendly.The second Cooling temperature TC; (in some embodiments the second fluid temperature TF;) is chosen in order to freeze the condensation 26 and the layer of pollutants 25 on the surface 28 of the conduits 13, The condensation thus turns into a layer of ice 26I. It is to be noted that the conduits 13, 14 are not always necessarily covered by the ice layer 26I.

Only when the cleaning process is underway is the ice layer 26I forced to form on the conduits 13, 14. Thus, energy is not required in order to keep the fluid or conduit at a temperature enough to freeze the condensation 26 at all times. The cleaning process is conducted at regular intervals. The time span between each cleaning event depends on the environment in which the battery device 10 is arranged, the air flow rate etc. lf the battery device 10 is in need of extra moisture in order to form condensation on the outer surface 28, moisture can be added, before causing the conduits 13, 14 to assume the second conduit temperature TC; - by for instance sprinkling water on the conduits 13, 14 with a sprinkle device. Altematively, or additionally, additional moisture is added before the particles adhere to the conduits. It is favorable to switch off the ventilation system function during the self-cleaning process. However, it is not mandatory to do so.

Such a sprinkle device may also be used to subsequently spray clean the conduits 13, The conduits 13, 14 are kept at the second temperature TC; until the formed layer of ice 26I and the layer of pollutants 25 crack, forcing the layer of pollutants 25 away from the outer surface 28, due to the low temperatures TC;, TF; In one embodiment, the conduits 13, 14 are kept at the second temperature TC; by circulating the fluid while adapting the air flow F. The cracked combination of layer of ice 26I and layer of pollutants 25 thus detach the layer of pollutants 25 from the conduits 13, 14 and fall off from the conduits 13, 14, at least when the conduits again assume a higher temperature, such as when the heat exchange system is turned off (whereby no fluid is circulated to cool the conduits), when the fluid is caused to assume a higher temperature or when the ventilation system is activated, whereby the flow of air will heat the conduits.In the following the process of the cracking the ice layer and particle layer will be disclosed in more detail. As can be seen in figure 10A the outer surface 28 of a conduit is shown in enlargement. It should be noted that the series of figures of 10A- 10D is not to scale and some proportions have been greatly exaggerated for illustrative purposes, such as the thickness of the condensation layer.

A condensation layer 26 is formed on the outer surface 28 when the conduit temperature is at the first conduit temperature (such as when the first temperature is above 0 degrees Celsius). It should be noted that the condensation layer may be formed through natural adsorption, especially when the conduit is made of metal, whereby no energy is needed for causing the condensation layer to be formed.

The condensation layer may be very thin and need not have a specific thickness. It should be noted though that since the cleaning process disclosed herein actually saves energy, it may be repeated many times and so a high efficiency is not necessary.

The condensation layer may also comprise fluids sprayed into the ventilation system.

As no surface is completely smooth, there will always be some pockets where condensation can be formed.

As is illustrated in figure 10A, the layer of pollutants 25 is irregular in its structure and especially its surface. There will thus be formed small pockets (P) of condensation between the layer of pollutants 25 and the outer surface 28 of the conduit. As is also illustrated in figure 10A, as the layer of pollutants is irregular and may also have been constructed in layers, possibly comprising several particles that are clumped together, there may also be holes (H) in the layer of pollutants that are filled (at least partially) with condensation or other fluids.

As is known, when liquids, especially water, freezes they expand. Figure 10B shows how the condensation layer expands as it turns into an ice layer 261. The expansion is indicated by the arrows indicating the direction of the expansion. As the outer surface 28 of the conduit is impermeable, or at least less permeable than the free air, the ice layer 261 will expand away from the outer surface 28. As it does so, the condensation in the pockets P will also expand and push the layer of pollutants 25 awayfrom the outer surface 28, thereby cracking the ice layer 261 and the layer of pollutants Furthermore, as the layer of pollutants and the condensation layer does not consist of the same material, they will expand at different rates as they freeze, which will also cause the ice layer 261 and the layer of pollutants 25 to crack. 1n addition to this, the holes H of condensation in the layer of pollutants 25 will also expand and possibly cause the layer of pollutants 25 to crack from inside forming cracks C.

Figure lOC shows the situation when the ice layer 261 has eXpanded and the layer of pollutants 25 has been distanced from the outer surface 28, that is, after the ice layer 261 and the layer of pollutants 25 has cracked. As the layer of pollutants 25 has been distanced from the outer surface 28 it loses- at least partially - its cohesion to or grip on the outer surface 28. Due to gravity some of the layer of pollutants 25 will fall off already at this point. 1t is thus not the ice layer that cracks, but it is the combined layer of the ice layer and the layer of pollutants that cracks as is indicated in the above.

Figure lOC also shows the situation where cracks C have been formed in the layer of pollutants As is noted above, the conduits are only kept at the lower temperature for a time period, and then allowed to assume a higher temperature (above 0 degrees Celsius), such as an inactive temperature or the first temperature whereby the ice layer 261 will melt. Figure lOD shows the situation when the ice layer 261 has melted and returned to a condensation layer 26. This is indicated by the arrows. As is illustrated in figure lOD, the layer of pollutants 25 is now distanced from the outer surface 28 and also, there is no ice layer 261 to hold it to the outer surface, and most or at least some of the layer of pollutants 25 will fall off the outer surface 28, as is indicated by the bold dotted arrow.

Due to gravity, later rinsing/spraying and/or the reintroduction of the air flow most of the layer of pollutants 25 will be caused to fall off the outer surface As noted above, this process is very energy efficient, and may thus be repeated regularly. 1n case there is a remaining layer of pollutants, as the conduits are caused to assume the first temperature again, a new or the same condensation layer Will form, but now in the pockets which have been made larger and also in any holes, which have been made larger, and/or cracks and as the conduits are again caused to assume the second temperature (being below 0 degrees Celsius), the ice layer 261 will again be formed, causing the ice layer and remaining layer of pollutants 25 to crack even more, and distance the remaining layer of pollutants 25 from the outer wall 28 even further, thereby increasing the likelihood of the remaining layer of pollutants 25 to fall off the outer wall The conduits 13, 14 have thus become cleaned with a self-cleaning process. Thereafter, the conduit is brought back to the first temperature or at least a temperature above 0 degrees Celsius, such as an inactive temperature. In one embodiment, this is achieved by the fluid being brought back to the first fluid temperature Tp1. ln one embodiment this is achieved by the air flow being re-adapted. Thus, also the conduits 13, 14 assume the first conduit temperature TC1 once more and the air cleaning process starts over again. Alternatively, the heat exchange system is turned off completely whereby the conduits assume the inactive temperature, assumingly being above 0 degrees Celsius as at least parts of the ventilation system is arranged indoors.

Should the ventilation system be arranged outdoors and the ventilation system is tumed off, the conduits will remain at the lower temperature until the ventilation system is tumed back on and the warm air flow from the restaurant recommences. The situation can then utilize the invention by using the turned off period as the period when the conduits are kept at the lower or second temperature and then form the ice layer cracking the ice and particle layer.

To summarize, with reference to figure 11, showing a flowchart of a general method according to herein, the manner of operating the self-cleaning ventilation system according to this application, thus comprises causing the conduits to assume 1102 a first temperature and to provide 1103 a flow of air. The conduits are caused to assume the first temperature by a fluid being circulated in the conduits and by being heated by the air flow. By circulating the fluid at least shortly before providing the flow of air enables for a condensation layer to be formed more efficiently before the flow of air - and the accompanying particles - first contact the conduits. As it will take sometime to cool the conduits, the conduits Will not freeze immediately upon receiving the fluid. The first temperature - at least as eventually reached during filtering - is above 0 degrees Celsius.

As the air flows through the ventilation system, particles being carried by the air flow will collide and adhere 1104 to the conduits. When they do, small pockets of condensation will be formed under the layer of particles, and as the conduits are caused to assume a second temperature, the condensation will freeze, possibly along with the layer of pollutants, and crack 1107 the layer of pollutants causing the layer of pollutants to lose (at least some of) its adhesion to the outer wall 28 of the conduit 13, 14. The ice layer may also crack due to the freezing. The second temperature - at least as eventually reached - is below 0 degrees Celsius. The conduits are caused to assume the second temperature by the fluid being circulated in the conduits being further cooled and/or by no longer being heated by the air flow - or to a reduced degree. By no longer heating the conduits, possibly by simply turning off the air flow, an energy saving manner of cooling the conduits is achieved as the manner of driving the air flow (possibly the fan) is tumed off or down.

The cracked layer of pollutants, and possibly some of the ice layer, detaches 1108 from the conduit, at least when the temperature is brought back to the first temperature, or another temperature, such as an inactive temperature, above 0 degrees Celsius.

The details of the battery device 10 according to one embodiment will now be described in more detail. The fluid is caused to assume the first fluid temperature Tp1. The pump 21, pumps the fluid with temperature Tp1 through the conduits 13, A preferred value of the first fluid temperature Tp1 when entering the battery device 10 is between -20°C and 10°C. The fluid may be arranged to run in a closed system of the battery device 10. The pump 21 can in other embodiments be replaced by for example a heat eXchanger, a heat pump or any other suitable device.

In a situation, the conduits 13, 14 have assumed the first conduit temperature TC1 by heat transfer from the fluid having the first fluid temperature Tp1. The flow of eXhaust air F flows into the ventilation system 1 and into the battery device 10.In one embodiment, the conduits 13, 14 have assumed the first conduit temperature TC1 by heattransfer from the fluid having the first fluid temperature Tp1 in combination with being heated by the flow of air.

A common temperature of the flow F of eXhaust air is between 18°C and 35°C.

A common va1ue of the first fluid temperature Tp1 of the fluid is between -20°C and 10°C. The first conduit temperature TC1, which the conduits 13, 14 assume when the fluid of temperature TR1passes through them, is s1ight1y higher than the first fluid temperature Tp1. This is due to the 1aws of thermodynamics.

This means that a temperature drop of the eXhaust air can be achieved. As the flow of air is activated the first conduit temperature, wi11 increase as the conduit (and the fluid) is heated by the flow of air. Thus, the fluid and the arrangement of conduits 13, 14 are configured to extract energy from the flow F of eXhaust air by coo1ing the eXhaust air by means of the fluid having the first fluid temperature TR Periodica11y, the bui1d-up of the partic1es, i.e. the po11utant1ayer 25, and condensation on the outer surface 28 of the conduits 13, 14, needs to be removed as is discussed above. That is, the battery device needs to be c1eaned. Cleaning is important in order to avoid increased resistance of the air flow and avoid the risk of c1ogging. Therefore, the temperature of the fluid is decreased to the second fluid temperature TRg. The second fluid temperature TF; is between 0°C and -60°C, preferab1y between -3 and -20°C, or between -5°C and -15°C and more preferred between -1°C and -10°C. The se1f-c1eaning effect is enhanced if the second fluid temperature TF; is app1ied in severa1 cyc1es or for a 1onger duration of time. As stated above, the fluid may be caused to assume the second fluid temperature by adapting the airflow as an a1ternative or in addition to active1y coo1ing the fluid.

Due to the first conduit temperature TC1 of the conduits 13, 14, condensation 26 from water bound in the eXhaust air has formed on the outer surfaces 28 of the conduits 13, 14. When the fluid is coo1ed to the second fluid temperature Tpg, the conduits 13, 14 assume the second conduit temperature Tçg, and the condensation freezes such that a 1ayer of ice 261 is formed on the outer surface 28 of each conduit 13, 14. Since the condensation forms c1osest to the conduit surface 28 at 1east a part of thepollutants adhere on top of the condensation, i.e. at least a part of the condensation is beneath the pollutant layer Eventually, the layer of ice 261beneath the layer of pollutants 25 eXpands and thus cracks the pollutant layer 25 due to the lower second fluid temperature Tpg. The lower second fluid temperature Tpg, compared to the first fluid temperature Tp1, causes the layer of pollutants 25 to contract and become brittle, which eventually lead to a blasting or cracking effect. When the layer of ice 261 and layer of pollutants 25 crack, the layer of pollutants 25 detach from and fall off from the conduits 13, 14. 1n some instances, where the layer of ice has been cracked in itself, the layer of ice 261 also fall off the outer surface 28. This temperature varying process, or freeze process, achieves self-cleaning of the conduits 13, 14 of the battery device 10 in the ventilation system 1. When the ice 261 and pollutant layer 25 has fallen off the conduits 13, 14, the temperature of the fluid is brought back to the first fluid temperature Tp1 or an inactive temperature, and the process may be started again. The unit may include a controller (not shown), which controls the temperature of the fluid, the interval at which the cleaning takes place, and various optional features, such as alarms for when there is a need for emptying collection means. The controller may e. g. control a compressor, by which the temperature changes of the fluid is handled.

A preferred cleaning interval, i.e. temperature change from the first fluid temperature Tp1 to the second fluid temperature TF; is once every 24 hours. However, this depends on the amount of particles/pollutants in the eXhaust air.

Thus, it is efficient and simple to form a layer of ice 261 on the conduits 13, 14 according to the present invention. The layer of ice 261 can be formed during high load cycles and the layer of pollutants 25 will fall off from the surface 28 of the conduits 13, 14 when the layer of ice 261 cracks the layer of pollutants 25, leaving no melted grease on the surfaces 28. 1n addition, no further chemicals, such as a surfactant, is needed to achieve a well-functioning self-cleaning process. During use, the flow F of eXhaust air is cooled by the cooled conduits 13, 14 and condensation is formed on the outer surfaces 28 of the conduits 13, Excess condensation water formed in the battery device 10 and on the conduits 13, 14 may be collected by the collection means and transported to a chamber 22. TheChamber 22 may also be used for collecting the cracked layer of ice 261 and layer of pollutants 25 during self-cleaning of the battery device The gathered condensation water and/or layer of ice 261, can in one embodiment be recycled in the self-cleaning process of the battery device 10. Optionally, the chamber 22 is connected to a heating device which is arranged to heat the ice 261 which has fallen off the conduits 13, 14 sufficiently to melt the ice 261. 1f the heating device is not used, the ice 261 will melt due to the temperature being above 0°C in the collection tray. The condensation water and/or the melted ice 261 can be sprinkled or sprayed on the conduits 13, 14 in order to add extra moisture to the outer surface 28 of the conduits 13, 14. Thus, the conduits 13, 14 can be wetted to ensure that an ice layer 261 is formed thereon to facilitate the cracking process. However, if the melted condensation water is to be recycled, a filter is preferably used to filter away the pollutants prior the sprinkling.

The sprinkler 23 device may further be included in either the battery device 10 and/or in the ventilation system 1. Advantageously, the sprinkler 23 device can gather water from the chamber 22. 1f the battery device 10 and the conduits 13, 14 need to be cleaned but there is no condensation to form an ice layer 261, water may be sprinkled onto the conduits 13, 14. 1f water from the chamber 22 is not enough, the chamber 22 can be connected to and use water from any other suitable water source (not shown), for example a tap in the room where the ventilation system 1 is in use. The sprinkler 23 device and optionally the above described heating device may further be connected to any regular water source if more water is needed during cleaning. 1t is however an advantage to be able to use the condensation water first and then add water from another source. To recycle the condensation is an advantage since it is a sustainable use of the ventilation system 1, without the necessity to add tap water and waste resources.

The sprinkler 23 device may be of use for instance if the ventilation system 1 and/or the battery device 10 has not been in use for a long time or if the eXhaust air is eXtraordinary dry. The relative humidity of the air alters depending on weather, climate and season for instance. When air is very dry, there is a risk that too little water is present in the air flow F to enable the formation of an ice layer 261. This is solved by the addition of moisture by means of the sprinkler 23 device.

The battery device 10 as described above has many advantages. The battery device 10 provides a built-in self-cleaning system. The efficiency of the cleaning of the ventilations system is thereby increased and also the risk of clogging in the ventilation system causing poor air quality and foul smell is diminished.

In one embodiment, at least one of the conduits 13, 14 is made of metal, Which further improves the adsorption.

In one embodiment, at least one of the conduits 13, 14 is coated to enable the pollutants to lose their adhesion more easily. In one such embodiment, the coating is nano-coating.

Figure 12 shows a schematic overview of an alternative embodiment, Where the distribution conduit 19 and the collection conduit 20 are arranged on opposite sides of the battery device, unlike in previously disclosed embodiments, Where the distribution conduit 19 and the collection conduit 20 are arranged on the same side of the battery device. By arranging the distribution conduit 19 and the collection conduit 20 on a same side of the battery device, the installation may be simplified as only one side need to be accessible.

Although the present invention has been described above With reference to specific embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the invention is limited only by the accompanying claims.

In the claims, the term “comprises/comprising” does not exclude the presence of other elements or steps. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. In addition, singular references do not exclude a plurality. The terms “a”, “an”, “first”, “second” etc. do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as lin1iting the scope of the claims in any Way.

Claims (5)

1. A battery device (10) arranged to be installed in a ventilation system (1) and arranged to eXtract energy from a flow (F) of air, said battery device (10) comprises: a housing (11) arranged to receive said flow (F) of air through a first end (11a) and at least g-“bent conduit arrangement§ (12) arranged inside said housing (11) to eXtend in a direction from the first end of the housing (11a) to a second end of the housing (11b), whereby said flow (F) of air will pass along the bent conduit arrangement (11) from the first end to the second end when said flow (F) of air is received by said housing (11), at least one bent conduit arrangement (12) comprises at least a first conduit (13) and a second conduit (14) arranged in a bent pattem eXtending in the direction of the bent conduit arrangement (12) and at a tilt angle (gamma) being in the range of 5 to -5 degrees relative the direction of the flow of air, wherein the first conduit (13) is arranged interleaved with the second conduit (14), wherein the bent pattem comprises a plurality of bent sections (12a) and a plurality of straight sections (12b), each of the straight sections (12b) being arranged substantially horizontally and in a first substantially perpendicular direction relative the flow of air, and the plurality of bent sections (12a) being arranged at the tilt angle, wherein a first bent conduit arrangement (12-1) is arranged parallel to a second bent conduit arrangement (12-2) at a vertical distance (D3), further comprising at least one support (17) having an upper side (17A) and a lower side (17B), the at least one support (17) being arranged between the first bent conduit arrangement (12-1) and the second bent conduit arrangement (12-2), wherein said support (17) is arranged to eXtend in a direction parallel to the flow (F) of air and comprises cutouts (17C) for receiving said first and second conduits (13, 14), wherein said cutouts (17C) are arranged on one side (17a, 17b) of the (17), wherein said cutouts (17C) are arranged as (17) and lower cutouts on a upper cutouts on an upper side (17a) of the lower side (17b) of the ,§gjg;>(17).

2. The battery device (10) according to c1aim 1, Wherein the upper side (17a) of ~ (17) is arranged at an angle re1ative the 1oWer side (17b) of the (17).

3. The battery device (10) according to c1aim 2, Wherein the ang1e is in the range 1-45 degrees, 10-45 degrees, 20-45 degrees, or 30-45 degrees.

4. The battery device (10) according to according to any of c1aims 1 to 3, comprising a first support (17-1) and a second support (17-2) Wherein said first support (17-1) is arranged in the direction para11e1 to the floW (F), and said second support (17- 2) is arranged turned in the opposite direction para11e1 to the floW (F).

5. The battery device according to any preceding c1aim, Wherein the battery device is connected to a heat exchange system (4,5).