Heat exchanger unit especially for electrostatic air filter, contains panels with perforated support and heat transfer film on one side

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PATENT INVENTOR INVENTOR'S OFFICE NAME

Eurus AirTech AB, Österskärsvägen 14 184 50 Åkersberga SE

Andrzej Loreth, Åkersberga SE, Jonas Törnblom,

Norrtelje Patentbyrå AB

Heat Exchanger Unit and Air Conditioning Assembly Including Such (56) PUBLICATIONS Cited: --- (57) SUMMARY:

The present invention relates to a heat exchanger unit (1; 1 '; 1; 1' '), preferably for single use, comprising a plurality of disc-shaped elements (2; 2'; 2; 2 ''; 2 '' '). spacers (7, 9) disposed between the disc-shaped elements (2; 2 '; 2; 2' ''; 2 '' ') are defined to define a plurality of channels (10, 11; 10', 11 '; 10, 11; 10 ', 11'; 10, 11) for supply and exhaust air (3, 5) respectively. The invention also relates to an air treatment unit.

The characteristic of the heat exchanger unit (1; i_; in_; 1 ') is that at least some of the disc-shaped elements (2; 2'; 2b; 2 '; 2) include a carrier (12) which is perforated, and that said disc-shaped elements (2; 2', · 2 "b ; 2 '; 2) on one side are coated / laminated with a foil (14) with good heat transfer properties. According to a preferred embodiment of the invention, the heat exchanger unit (1; 1 '; 1; 1') can simultaneously function as condensers of so-called 1 year e.

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The numbers in brackets indicate International identification code, INID code. Letters in clamps indicate international document code.

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Technical field of the invention

The present invention relates to a heat exchanger unit, preferably for single use, comprising a plurality of disc-shaped elements arranged by means of the spacer elements disposed between the disc-shaped elements to define a plurality of channels for respective exhaust air. The invention also relates to an air treatment unit comprising a heat exchanger unit according to the invention.

The prior art

The energy crisis in the late 1970s resulted in our homes becoming increasingly airtight. The uncontrolled entry and exit of air (self-suction) has been replaced by controlled ventilation. The overall aim was to take advantage of the exhaust air heat and heat the cold supply air with the recycled energy.

The use of heat exchangers increased and also the use of air filters on both the supply air and exhaust air side. The latter was mainly to protect heat exchangers from contamination and thereby from degraded operating parameters. The rapidly increasing frequency of asthmatic / allergic diseases over the past 20 years has increasingly focused attention on the indoor environment and its impact on these diseases. Demands for better indoor air quality grew.

In recent years, billions have been invested in new ventilation systems, especially in schools and nurseries. Despite this, expectations of good indoor air have not been met. Therefore, it is attempted, among other things, to try the use of room-placed individual air treatment systems in order to avoid the transport of air through long ventilation ducts. These units, like ventilation units, consist of heat exchangers that are protected by fine filters from both supply air and extract air side, which, due to the resulting pressure drop, greatly limits their capacity and complicates both construction and maintenance. This in combination with relative

513 603 expensive installation costs mean that the use of such units is very limited.

The objects and features of the invention

A primary object of the present invention is to create a heat exchanger unit, preferably for single use, where in the usual way an energy exchange takes place between supply air and exhaust air. Disposable means that the heat exchanger is made of materials that can be incinerated or reused.

A further object of the invention is that the heat exchanger unit can be modified in such a way that it simultaneously functions as an electrostatic air purifier, preferably for the supply air.

Yet another object of the present invention is that the heat exchanger unit / air purifier should have low weight relative to its effective surface, the low weight facilitating replacement of the heat exchanger unit / air purifier when it is consumed.

At least the primary object of the present invention is realized by means of a heat exchanger unit having obtained the features set forth in the following independent claim 1. Preferred embodiments of the heat exchanger unit are defined in the dependent claims.

Brief description of the drawings

Below, embodiments of the invention will be described with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a schematic diagram.

heat exchanger unit of the present invention;

Figure 2 shows on a larger scale a section through a portion of an element included in a heat exchanger unit;

Fig. 3 shows a transparent perspective view of an air conditioning unit, which includes a heat exchanger unit according to the present invention;

Fig. 4 shows a transparent perspective view of an air treatment unit, which includes partly an ionization chamber and a heat exchanger unit /

513 603 capacitor separators of the present invention;

Fig. 5 is a schematic side view of the air treatment assembly of Fig. 4, showing the electrical arrangements of the ionization chambers and the capacitor separator;

Fig. 6 is a perspective view of an alternative embodiment of a heat exchanger unit / capacitor separator according to the present invention;

Fig. 7 is a schematic side view of the structure and electrical arrangements of the heat exchanger unit / capacitor separator of Fig. 6;

Fig. 8 shows a heat exchanger unit according to the present invention operating without a mechanical fan; and Fig. 9 shows a detail of two elements which are curved in a heat exchanger unit.

Detailed Description of Preferred Embodiments of the Heat Exchanger / Air Purifier of the Invention

The first embodiment of a heat exchanger unit 1 according to the present invention is shown schematically in Fig. 1.

The heat exchanger unit 1 according to Fig. 1 comprises planar elements 2 which are parallel to each other and with a mutual gap distance d, these elements being arranged so that two separate, symbolized arrows, air streams 3 and 5 respectively can pass the heat exchanger unit 1 without mixing. In this way, the air stream 3 can constitute supply air and the air stream 5 exhaust air. As Fig. 1 shows, this is accomplished by separating two adjacent elements 1 by means of spacers 7 and 9 respectively in the way that air supply ducts 10 and exhaust air ducts 11 are formed, all air ducts 10, 11 of the embodiment shown having a rectangular cross-section.

The spacer elements 7 and 9, respectively, are arranged at different levels and extend substantially perpendicular to each other.

This means, in accordance with the embodiment shown in Fig. 1, that the air ducts 10 and 11, respectively, are perpendicular to each other and arranged alternately on different

513 603 levels. In this context, it should be noted that the gap distance d may be different for the supply air and exhaust air ducts respectively.

It can be seen from Fig. 2 that the elements 2 comprise a carrier 12, the starting material used in the manufacture of said carrier 12 being preferably used a polyethylene coated cardboard type Invercote® from Iggesunds Pappersbruk AB. To form the carrier 12 according to the present invention, the starting material is provided with perforations (holes) 13, indicating as a guide value that 60 -95% of the surface of the carrier 12 can be perforations. In this connection, however, it must be taken into account that even after the perforations 13 are taken up, the carrier 12 must exhibit sufficient mechanical stability.

Subsequently, the support 12 is laminated with an aluminum foil 14. It has surprisingly been found that such lamination is possible by hot coating the aluminum foil 14 when applied to one side of said support 12. At the hot overcoating, the polyethylene coating melts on one side of the support 12, said molten coating serves as a binder between the carrier 12 and the aluminum foil 14. In the embodiment of element 2 shown in Fig. 2, the aluminum foil 14 is applied to the underside of the carrier 12, whereby within the scope of the invention it can equally be applied to the upper side of the carrier 12. To achieve the best heat transfer properties, extra thin aluminum foil (about 0.010.02 mm) is preferably used.

Fig. 3 shows an air handling unit for room placement. Said assemblies include a heat exchanger unit 1 according to the present invention, in the corresponding manner as indicated in Fig. 1 supply air, symbolized by the arrows 3, passes through the heat exchanger unit 1 in a first direction and extract air, symbolized by the arrows 5, passes through the heat exchanger unit 1 in a second direction, the first and second directions being perpendicular to each other.

Upstream of the heat exchanger unit 1, seen in the flow direction of the supply air 3, is provided an electrostatic particle filter comprising a

513 603 ionization chamber 15 with a corona electrode 16, a capacitor separator 17 and a high voltage unit (not shown). Said electrostatic particle filter is designed in a known manner and in this context can be referred to SE-B-469 466, WO 96/11060 and WO 97/46322, which show electrostatic particle filters which can be used in an air treatment unit according to Fig. 3. This means that the the incoming supply air 3 is cleaned before passing through the heat exchanger unit 1. Extract air 5 is not purified at the air treatment unit of Fig. 3, as it is normally returned to the outside air via the outlet 18 of the air treatment unit of Fig. 3. In addition, a disposable heat exchanger does not need to be protected from contamination in the same way as a traditional heat exchanger. In many cases, only filters on the supply air side can suffice. In this context, it should be pointed out that the absence of filters means that pressure drops are avoided.

However, within the scope of the invention, of course, it can also be thought that the exhaust air 5 is purified in the same way as the supply air 3. In this connection it should be mentioned that it is in no way necessary that, for example, the purification of the supply air takes place by means of an electrostatic particle filter. It is quite possible to purify the air by other filters, for example mechanical, but these generally cause a substantially larger pressure drop than an electrostatic particle filter.

In some environments, e.g. In areas with wood burning, the supply air may contain corrosive substances. Therefore, there may be a need to epoxy-coat the aluminum foil or to ensure that the heat exchanger is changed more frequently.

The air transport through the particle filter and the heat exchanger unit 1 can be carried out in an appropriate manner, for example by mechanical fans or by self-drawing.

The construction of an air treatment device according to the above creates the conditions for the construction of large units to its volume, which provides better conditions for both heat recovery properties and particle filtration, whereby both of these functions occur without significant pressure drop, ie without expensive energy costs and with exceptionally simple maintenance.

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The size of the device is of significant importance with regard to condensation in exhaust air ducts. At very small gap distances between the respective elements 2, the pressure drop due to condensation can increase by a couple of hundred percent against the pressure drop over the same unit without condensation. Therefore, it is of great practical and economic importance that a surface enlargement of the heat exchanger can be achieved and thus sufficiently high air flow ducts (gap spacing). A preferred gap distance d for the exhaust air ducts 11 can be between 4 and 10 mm.

The air handling unit shown in Fig. 4 is supplied in a manner similar to that of the air handling unit of Fig. 3, supply air 3 and extract air 5, the directions of these air flows being substantially perpendicular to each other.

The air treatment unit of Fig. 4 includes a heat exchanger unit / capacitor separator 1 'which corresponds to the heat exchanger structure 1 of Fig. 1 in principle. in the manner shown in Fig. 5, i.e. the elements 2 'constitute electrode elements. Said electrode elements 2 'have a structure corresponding to the elements 2 according to Fig. 2, ie a carrier of polyethylene coated cardboard of type Invercote® from Iggesunds Pappersbruk AB. This works great for electrode elements that are part of a capacitor separator as cardboard is a high-resistance material. As can be seen in Fig. 5, the electrode elements 2 'which define a supply air duct 10' are of different potential, ie an electrode element 2 'is grounded and an electrode element 2' has a potential of - 3-6 kV, while the electrode element elements 2 'which define a exhaust duct 11 'is at the same potential, that is, both are grounded or both have, via a high voltage source 19', been given a certain equal potential of the order of 3-6 kV. Thus, the electrostatic field between the electrode elements 2 'defining an exhaust duct 11' is equal to zero (the field in a so-called Faraday's cage).

In this connection it should be pointed out that it is advantageous if the supply air ducts 10 'are delimited by the side of the

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Ί The electrode elements 2 'which consist of high-resistive material because they have different potential and there is less risk of transposition between surfaces of high-resistive material. This means that the exhaust air ducts 11 'will be delimited by the side of the electrode elements 2' coated / laminated with aluminum foil, which can be an advantage from the aspect that there is a risk of condensation in the exhaust air ducts 11 ', whereby said condensation is easier can run from aluminum foil.

The air treatment assembly of Fig. 4 also includes an ionization chamber 15 'with a corona electrode 16'. An associated high voltage source 20 'provides for electric charge of particles in supply air 3 via the corona electrode 16' in the ionization chamber 15 '.

The air transport through the ionization chamber 15 'and the heat exchanger unit / capacitor separator 1' can be carried out in an appropriate manner, for example by mechanical fans or by self-drawing.

The air treatment assembly of Fig. 4 works in such a way that the particles in the supply air 3 entering the ionization chamber 15 'are charged by the corona electrode 16'. Thereafter, the supply air 3 passes into the supply air ducts 10 ', whereby the electrostatic field present in said supply air ducts 10' causes the charged particles to settle on the electrode elements 2 'which define said supply air ducts 10'. Since said electrode element 2 'is preferably coated / laminated with aluminum foil only on its one side, preferably the side which is not coated with aluminum foil may define the associated supply air duct 10'.

As pointed out above, the electrostatic field in the exhaust air ducts 11 'is equal to zero, which means that the particles transported through the exhaust air ducts 11', regardless of whether the particles are charged or not, will not be separated from the exhaust air stream. However, this is perfectly acceptable as there is normally no need to clean the exhaust air which is transferred to the outdoor air.

The alternative embodiment of a heat exchanger unit / capacitor separator 1 shown in Figs. 6 and 7 differs.

513 603 from the corresponding unit according to Figures 4 and 5 at a number of points. However, it should be mentioned at the outset that the heat exchanger unit / capacitor separator 1 according to Figs. 5 and 7 is intended to be included in an air treatment unit of the same kind as that in Fig. 4, ie an ionization chamber is provided upstream of the heat exchanger unit / capacitor separator 1 in the supply air flow.

As can be seen most clearly in Fig. 7, two supply air ducts 10 are arranged in pairs next to each other, said supply air ducts 10 being mutually defined by a common electrode element 2a of high-resistance material, preferably polyethylene-coated cardboard of type Invercote® from Iggesunds Pappersbruk AB. These electrode elements 2a are not coated / laminated with aluminum foil and do not exhibit perforations. The other electrode elements 2b constitute one boundary for the supply air ducts 10 and both the delimiters for the exhaust air ducts 11. These electrode elements 2b have a basic structure corresponding to the elements 2 / the electrode elements 2 ', ie they have a cardboard carrier, are coated / laminated with aluminum foil. perforated.

In the embodiment of Figs. 6 and 7, the high-resistance material electrode elements 2a have a potential of 3-6 kV, by means of the high voltage source 19, while the laminated and perforated electrode elements 2b are grounded. The connection of the electrode elements 2a, 2b to the high voltage source 19 and to the ground, respectively, takes place in a conventional manner. However, it may be appropriate that electrode elements 2a are connected to the high voltage source 19 via high-ohmic resistors, which arrangement means that it is not as critical to protect the electrode elements 2a from contact.

The air transport through the heat exchanger unit / capacitor separator 1 can be carried out in an appropriate manner, for example by mechanical fans or by self-suction.

The heat exchanger unit / capacitor separator 1 shown in Figs. 6 and 7 functions in such a way that the supply air 3 entering the channels 10 contains charged

513 603 particles, which are deposited on the electrode elements. 2a of high-resistance material because there is a potential difference between the electrode elements 2a, 2b defining the supply air ducts 10. The particles in the exhaust air passing through the ducts 11 are not deposited on the electrode elements 2b, whether or not they are electrical charge carriers, as said electrical elements 2b is at the same potential (Faraday's cage) and according to the embodiment shown, they are grounded.

For those embodiments which include so-called electrode elements 2 '; 2b, which are coated / laminated with aluminum foil, it is advantageous if the aluminum foil does not extend all the way to the edge of the electrode elements 2 '; 2b without there being a circumferential edge portion constituted by the carrier, which preferably consists of high-resistance material. Thereby the risk of breakage between the electrode elements 2 'is reduced; 2b.

A heat exchanger according to the present invention can also be used without fans. However, it is a prerequisite that there are no significant pressure drops in the device so that temperature differences and thus the different weight of the air can be utilized and that the space in which the heat exchanger is placed is not disturbed by other ventilation systems. Such conditions can prevail in many homes.

Fig. 8 shows an embodiment of a heat exchanger unit 1 '' 'according to the present invention operating without a mechanical fan. The unit 1 '' 'according to Fig. 8 is placed vertically near an outer wall or window, whereby the unit supply duct 10' '' is connected to an inlet 21 '' 'for outdoor air / supply 3 at the upper end of the unit 1 and partly the unit 1 '' 'exhaust duct 11' '' is connected to an outlet 22 '' 'at the lower end of the unit 1 for exhaust air 5 into the outdoor air. Thus, as can be seen from Fig. 8, the inlet 21 '' 'of the supply air 3 is located higher than the outlet 22' 'of the exhaust air 5.

Although not shown in Fig. 8, the supply air duct is used

10 '' and the exhaust air duct 11 are completely separated from each other, ie there is no mixing of supply air and exhaust air, but the energy transfer between the supply air and the extract air takes place through boundaries, which are in principle constructed

513 603 of a perforated carrier and a foil of a material with good heat transfer properties.

The device shown in Fig. 8 works in such a way that the cold supply air 3 flows downward due to its weight which is greater than the hot exhaust air 5. The hot exhaust air 5 flows / is drawn downwards through the exhaust air duct 11 supply air and become heavier the further down in the exhaust duct 11 '' 'it is located. The unit 1 '' 'operates as a pump or according to the laws of nature which control ventilation through open windows, ie the cold air flows through the lower part of the window towards the floor and extends the warm air at the ceiling through the upper part of a window.

Charging of particles in the supply air should take place closest to the inlet 21 '' 'in a previously known manner. The embodiment of Fig. 8 is of course more efficient the longer the air flow ducts 10 '' ', 11' '' are.

In Fig. 9 it is shown how element 2 '' 'contained in a heat exchanger unit according to the present invention can be imparted to a curved shape. If the elements 2 '' '' are imparted to said curvature, it is easier to obtain a constant mutual distance between the elements between the spacer elements.

Possible modifications of the invention

In the above-described embodiments, aluminum foil 14 is used, which is laminated to the carrier 12. However, within the scope of the invention, it is also contemplated to use foils of other materials, whereby exemplary and non-limiting purposes may be mentioned other than aluminum, paper or plastic. In general, for the foil used, it has good heat transfer properties, which in this context can also be achieved if the foil is extremely thin. In addition, the foil should exhibit a certain electrical conductivity, ie semi-conductive or antistatic materials can be used. The foil should also be moisture resistant.

In the above-described embodiments of Figures 3 and 4, the particles are charged into the air in an ionization chamber.

However, within the scope of the invention, it is also conceivable that the particles are charged differently.

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In the embodiments described above, some of the electrode elements are grounded. In this context, however, it should be noted that within the scope of the invention, it is not necessary for said elements to be grounded, they may also be subject to a certain voltage.

The heat exchanger units / air treatment units described above are preferably stated to be room-located. However, within the scope of the invention, it is also conceivable that they are located in ventilation ducts.

In the following claims, it is stated that the elements contained in the heat exchanger unit / capacitor separator are disc-shaped. By this term, it is to be understood in this context that capacitor separators according to, for example, WO 97/46322 are also considered to include disc-shaped elements, which in the present case have obtained a curved shape. Namely, it is the case that capacitor separators according to WO 97/46322 can be used as heat exchanger units through suitable arrangements, in which case two separate groups of ducts for supply air and exhaust air are arranged. It is also conceivable that the disc-shaped elements are curved into cylindrical shape, the elements being concentric relative to each other.

There are thus a large number of possible solutions, however, in general it should be possible to arrange two groups of separated air ducts.

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