EP1535000A1

EP1535000A1 - Device and method for air treatment

Info

Publication number: EP1535000A1
Application number: EP03791176A
Authority: EP
Inventors: Rosella Rizzonelli
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-08-30
Filing date: 2003-08-19
Publication date: 2005-06-01
Also published as: ITBS20070034U1; AU2003264871A1; ITTN20020016A1; WO2004020913A1

Abstract

Fan-convector comprising: a motor fan (1) conveying air of the room to be conditioned to a finned heat exchanger (2) and to a second natural radiant and convective heat exchanger (3). These two elements are associated to a frame (4) comprising: an air outlet rack (6), an air cleaning filter (5), and two ducts (9) and (11) for conveying air and two or more basins (8) for collecting condensation water. The coordinated working of the two heat exchangers and of the fan generates a heat diffusion both by convection with mechanical ventilation and by natural irradiation and convection.

Description

DEVICE AND METHOD FOR AIR TREATMENT

DESCRIPTION The present invention relates to a device and a method for air treatment in rooms, and therefore for heating, cooling or dehumidifying air.

It is known about air treatment devices known as fan- convectors, which are used in domestic and industrial installations such as terminals for heating or cooling and dehumidifying air. In more sophisticated applications they can also carry out dehumidification through the combined effect of a cooling and dehumidifying battery and a pos -heating battery.

The primary operating fluid (i.e. circulating within the heat exchanger) can consist of water or other fluids that are able to convey heat both by conduction and by state change (through gas evaporation or condensation processes) .

The secondary fluid (circulating outside the exchanger) consists of humid air.

Heating, cooling or thermodynamic treatment (in case of saturated steam compression systems) of the primary fluid are carried out at the state of the art by means of central units consisting of devices such as: boilers, water refrigerators or motocondensing units (outer units of air conditioners) with or without heat pump system, electrical resistances, solar panels, heat regenerators, absorption cycle machines, etc. The primary fluid is supplied through pipes connecting the user or treatment unit, for instance the fan- convector, to the heat generation or absorption unit. One or more fan-convectors for conditioning the various rooms can be mounted in a single installation. Present fan-convectors basically consist of the following components:

A ventilation group circulating air on the heat exchanger. This ventilating system can be centrifugal (suction from fan center and intake conveyed by a suitable screw conveyor into a precise direction) or tangential (suction of fluid filaments tangential to fan diameter, with dynamic acceleration of air flow, through the principle of central vortex with cut-off area) .

A heat exchanger primary fluid-air comprising a series of parallel pipes (generally made of copper) arranged according to precise geometries, onto which is fastened with an excellent mechanical and thermal contact a series of thin low-thickness metal sheets (generally made of aluminum) . Pipes are connected one to the other through suitable bends having pipe diameter, so as to form one or more closed circuits in which the primary fluid circulates. Metal sheets can be more or less spaced one from the other. Their aims is to better dissipate heat contained in the primary fluid, or in case of cooling operation, to transmit heat contained in air (or secondary fluid) to pipes and then to the primary fluid. Heat exchangers are equipped with suitable connections.

Metal sheet or plastic carrying structure anchoring the components described above and ensuring the fastening or resting of the device onto a wall, ceiling or floor.

Metal or plastic cabinet for aesthetic covering and closing of inner air ducts. If the fan-convector is not in sight (false ceilings, engine rooms, etc.) the outer cover has only a functional and not an aestheti- cal purpose, and is therefore made of metal sheets or simple plastic boards.

Suction and intake racks for treated air. For hidden machines these devices are not among the accessories of the fan-convector, but are chosen by the installer depending on contingent needs. Air intake racks are often adjustable so as to choose flow direction. Electric or electronic control panel for managing functions, mainly present in accessible fan-convector located within rooms to be conditioned. Air filter. This device can be mechanical, electrostatic or with active carbons. In some cases these technologies are combined together into one component . The working of present fan-convectors is therefore based only on the principle of convection by mechanical ventilation. The fan-convector ensures - thanks to mechanical ventilation - large air flows that can convey large amounts of heat with relatively small exchange surfaces. This feature is even more relevant the greater absolute temperature differences between primary fluid and air. In particular, in case of cooling function, where there are small temperature differences between the fluids, ventilation is very important to ensure sufficient heat conveyance in small- size devices (that can be integrated into any room) . However, said fan-convectors have some drawbacks, since in case of absence of the air flow generated by the working of the motor fan, thermal yield values, also for heating, are very low and therefore insufficient to keep thermal conditions in the room. The constant ventilation further generates some negative effects such as: a more or less relevant noise and a continuous movement of air and dusts, containing substances dangerous for the human organism. At the state of the art it is also known about radia- tors that are commercially available at present in various technical embodiments (cast iron or aluminum meltings, cold forming of steel sheets, assembly of pipes or extruded profiles and laminates, etc.), which are based only on natural convection and irradiation principles. Their limitations are a low heating power with respect to their size and the absence of a cooling function. The low specific power of radiators results in a long starting stage for winter thermal conditions in rooms, especially starting from very low inner temperatures .

Under these circumstances the technical task underlying the present invention is to conceive a device and a method for air treatment that can basically obviate the aforesaid drawbacks .

In the framework of said technical task an important aim of the invention is to conceive a device and a method for air treatment that can combine the advantages of a system exploiting natural irradiation and convection with those of a system exploiting convection with mechanical ventilation. Another aim of the invention is to carry out a device and a method that enable a coordination of the operations performed by the single components and thus an optimal air treatment. A further aim of the invention is to conceive a device and a method enabling a particularly effective and efficient air treatment. Further aims of the invention are to conceive a device and a method that are easy to be carried out and to be used and with low costs.

The technical task and the aims referred to above are basically achieved by a device and a method characterized in that they comprise one or more of the technical solutions claimed below.

The following contains by way of merely illustrative and non-limiting example the description of a preferred - though not exclusive - embodiment of a device and a method according to the invention, shown in the accompanying drawings, in which:

- Figure 1 shows a perspective view of a device according to the present invention;

- Figure 2 is a view corresponding to the one in Figure 1, in which the front portion of the device frame has been removed;

- Figure 3 shows a lateral sectioned view of the device in Figure 1;

- Figure 4 schematically shows three possible assembling positions of the device of Figure 1 in a room. With reference to the figures mentioned above, the device for air treatment according to the invention is globally referred to with reference number 15. The device 15 comprises a frame 4 housing ventilating means 1, comprising for instance a conventional mechanical ventilation system, preferably a motor fan 1. The carrying structure or frame 4 ensures the fastening of the various components and is also necessary for anchoring the whole device 15 to the wall, ceiling or floor.

Through the ventilation means 1 air is sucked from outside thanks to an inlet opening 16 letting air into the frame 4 and conveyed into a first duct 9 within the frame 4 towards a convective heat exchanger (for instance a finned battery) or first heat exchanger 2. The device 15 further comprises a screw conveyor 7. The motor fan 1 can be carried out by exploiting the principles of the various aeraulic machines known at present (centrifugal, radial, tangential or axial machines) . In said exchanger 2 heat is transferred between the primary operating fluid circulating in the pipes or ducts 10 connected to the first heat exchanger 2, and air itself. After being treated by the first heat exchanger 2, air flows through a second duct 11 of the frame 4 till it gets again outside through the rack 6 or through a further duct and dif- fuser assembled during the installation of the device 15 .

The device 15 further comprises two collection basins 8 through which condensation water that forms on the convective exchanger 2 during cooling and dehumidifi- cation operation is drained. In particular, the basins 8 help to collect condensate when the device 15 is in standing position 12 close to the ground, in horizontal position, for instance when placed 14 on the ceiling, or upside down, as it is when placed 13 in the high part of the wall (see Figure 4) .

A filter 5 is advantageously mounted onto the inlet opening 16, which filter can be directly placed on the device or separately mounted by the installer. The working principle of the filter 5 can be by mechanical sieving (mechanical separation of dusts from air) , electrostatic (where thanks to an electrostatic potential difference between some suitably shaped electrodes dust is attracted on the latter) , or by active carbons (where polluting substances with very small molecules are adsorbed) . In Figure 3 convenient arrows show air inlet 19 and outlet 20 flows from the frame 4.

According to the present invention, in the front portion of the device 15 there is a natural radiator- convector or second heat exchanger 3, operatively con- nected to the ducts 10, in which the primary fluid circulates in series or parallel to the convective exchanger with mechanical ventilation 2. The second exchanger 3 can be differently sized and carried out. The function of the radiator 3 is to ensure - even if the motor fan 1 is not working - a good thermal yield both by radiant and natural convective effect. The device 15 can therefore advantageously comprise a radiant fan-convector with natural convective and radiant effect, deriving from the second exchanger, and with convective effect with mechanical ventilation, deriving from the first exchanger 2.

In short, the invention combines and coordinates the operation of the components constituting a traditional fan-convector with an integrated element having natural radiant and convective effect without the need for mechanical ventilation. This element, the second exchanger 3, is preferably positioned on the front portion of the device 15, so as to perform its function correctly and to act also as an aesthetic cover. The coordination and automation of the working of the various components are achieved thanks to convenient electromechanical and electronic devices or through mechanically driven valves. In short, the working of the device 15 is managed by control and coordination means 17 of the working of the various components, which are schematically shown in the figures and can comprise automatic devices (electronic control cards) or partially manual devices (keys and electromechanical adjustments) , which control mechanical means such as valves and the like for the selection of suitable flows in the ducts 10. In other words, said control and coordination means 17 can comprise control circuits known per se, which are therefore not described in further detail. The device 15 is further equipped with a heat generation or absorption unit, not shown in the accompanying drawings since it is of a conventional type, opera- tively connected through the ducts 10 to both heat exchangers 2 , 3.

The device 15 described above can be advantageously integrated into an air treatment unit which can comprise a plurality of devices 15 and at least a central heat generation or absorption unit operatively connected to said devices 15 through the ducts or connection lines 10.

In accordance with a method for air treatment according to the present invention, the control and coordination means 17 of the working of the first and second exchanger comprise an adjustment and control system operating on the basis of electromechanical, electronic or thermodynamic principles ensuring the highest comfort during use.

For instance, the working of the various components can be affected by the difference between room temperature and the temperature requested by the user. More to the point, when there is a considerable difference between the temperature detected in the room and the desired temperature (for instance delta T > 5- 6°C) , the fan starts working in order to ensure a large heat flow that will rapidly heat or cool the room. When the temperature difference lowers (for instance delta T < 1-2°C) , the fan automatically stops and the natural radiant-convective exchanger allows to keep comfort temperature unchanged.

In short, a method for air treatment in a room according to the present invention basically comprises the following steps:

- measurement of the difference between room temperature and a temperature required by a user;

- room air treatment by convection through forced ventilation if said difference is above a given value;

- stop of forced ventilation when the difference is below said given value; and

- room air treatment by natural irradiation and con- vection so as to keep the difference unchanged basically on said given value.

The step in which room air is treated by natural irradiation and convection can be carried out as an alternative to or also simultaneously to the step in which room air is treated by convection through forced ventilation.

The invention has important advantages . In particular, it should be pointed out that the invention combines the potentialities of a convective system with mechanical ventilation with the comfort of a radiant-convective system.

The performances of the device thus conceived are definitely better for rapidly achieving and keeping room thermal comfort, especially during heating operation.

Also temperature control becomes much more precise thanks to a power supply during heating and cooling which is proportional to differences between room temperature and the temperature required by the user. Finally, it should be pointed out that the invention allows to obtain a device and a related method for air treatment which are easy to be carried out, simple and convenient to be used and with particularly low costs.

Claims

1. Device for air treatment comprising a supporting frame (4) , a first heat exchanger (2) operating by convective effect, housed in said frame (4) , and ventilation means (1) generating an air flow through said first heat exchanger (2) , characterized in that it further comprises a second heat exchanger (3) , operating by natural irradiation and convection, associated to said frame (4) , and control and coordination means (17) for the working of the first (2) and second exchanger (3) .

2. Device according to claim 1, characterized in that it comprises a radiant fan-convector for air heating, cooling and/or dehumidification.

3. Device according to claims 1 or 2 , characterized in that said first exchanger (2) and said second exchanger (3) are operatively connected through ducts (10) for circulating a primary operating fluid.

4. Device according to claims 1, 2 or 3 , characterized in that said second exchanger (3) is associated outside said frame (4) .

5. Device according to any of the preceding claims, characterized in that the second exchanger (3) is mounted onto the front portion of the frame (4) .

6. Device according to any of the preceding claims, characterized in that said ventilation means (1) are mechanical and comprise a motor fan (1) .

7. Device according to claim 6, characterized in that said motor fan (1) is tangential.

8. Device according to any of the preceding claims, characterized in that it can be installed in a plurality of assembling positions, low-wall (12) , high-wall (13), turned upside down of 180°, or on the ceiling (14) in horizontal position.

9. Device according to claim 8, characterized in that it comprises two collection basins (8) for draining condensate water forming on the first exchanger (2) during cooling and dehumidification operation, arranged so as to collect condensate in all different assembling positions.

10. Device according to any of the preceding claims, characterized in that it further comprises an air filter element (5) of mechanical or electrostatic type or with active carbons, arranged on an air inlet opening (16) letting into the frame (4) .

11. Device according to any of the preceding claims, characterized in that the control and coordination means (17) for the working of the first (2) and second exchanger (3) comprise automatic devices, such as electronic control cards, and partially manual de- vices, such as keys and electromechanical adjustments, which control mechanical means, such as valves and the like, for the section of primary fluid flows in both exchangers (2, 3) .

12. Device according to any of the preceding claims, characterized in that the first heat exchanger (2) is supplied with a refrigerant other than water-

13. Device according to any of the preceding claims, characterized in that said first exchanger (2) comprises a finned battery.

14. Device according to any of the preceding claims, characterized in that it combines the convective effect achieved by the ventilation means (1) and by the first heat exchanger (2) with the natural radiant- convective effect of the second exchanger (3) .

15. Device according to any of the preceding claims, characterized in that it further comprises sensor means (18) for detecting the temperature of the room in which the device (15) is installed and the temperature of the primary fluid.

16. Device according to any of the preceding claims, characterized in that said frame (4) is provided with a first air duct (9) housing said ventilation means (1) , and with a second air duct (11) operatively connected to the first duct (9) and housing said first exchanger (2) , and with an air outlet rack (6) arranged at the end of said second duct (11) .

17. Air treatment unit, characterized in that it comprises a plurality of devices (15) according to any of the preceding claims, and at least a central heat generation or absorption unit operatively connected to said devices (15) through connection lines.

18. Method for air treatment in a room, characterized in that it comprises the following steps:

- stop of said forced ventilation when said difference is below said given value; and

- room air treatment by natural irradiation and convection so as to keep said difference unchanged basically on said given value.

19. Method according to claim 18, characterized in that said step in which the air of said room is treated by natural irradiation and convection is also carried out simultaneously to said step in which the air of said room is treated by convection through forced ventilation.