Granular balancer of air composition between separate zones with different ambient conditions

Abstract

Device for balancing the air composition between separate zones with different ambient conditions, reducing heat transmission by convection and mixing of unnecessary components as well as sound transmission, containing a section of the connecting duct between zones filled with one or several groups of granular behaviour over a length related to the type of granular element used and the final performance provided.

Description

Technical area

[0001] The present invention relates to a device for balancing the air composition between separate zones with different environmental conditions, which reduces the transmission of heat and noise between them. It is applicable in regulating the levels of indoor air components such as carbon dioxide, radon, formaldehyde, formaldehyde, humidity, etc., in relation to the outdoor environment. It is also applicable between rooms in the same building that have different environmental requirements such as classrooms-hallways, offices-staircases, workshops-storerooms, bedrooms-lounges, etc. It is also applicable in industrial processes such as the reduction of environmental humidity in cold rooms, etc. Finally, it should be noted that it can be used as a single device or as a complement to other systems, such as duct networks with mechanical ventilation.Background to the invention

[0002] The presence of unwanted components in indoor air is usually greater than in outdoor air, since they are produced by the activity itself, the presence of users, building materials, installations, furniture, appliances, etc. This makes it possible to reduce the unwanted components in indoor air by mixing it with outdoor air and can be done by opening communication gaps between the two environments. The problem is that direct communication also alters the environmental conditions, mainly temperature and noise, resulting in additional energy loss and consumption. There are currently two approaches to minimise the problem: a) Active, which involves the construction of networks of ducts, fans and energy recuperators by heat exchange between surfaces in common contact but is costly and very difficult to implement in existing buildings, which are the vast majority. b) Passive, which can be implemented in any building and consists of direct communication between zones using mechanisms to control air flows and minimise the problems derived from this direct communication. There are two different types and to date they are described in the Spanish CTE-HS3 standard as follows: b.1) "Micro-ventilation device: a fixed opening in a window frame allowing a very small amount of ventilation sufficient to ensure the required flow rates". b.2) "Aerator device: a device fitted to the inlet openings to properly direct the flow of air and prevent the entry of water and insects or birds. It may be adjustable or fixed aperture and may be fitted with additional elements to provide adequate sound attenuation.

[0003] The first b.1) is as simple as opening a window very little at the user's will, a slit. It is designed for a given wind speed and temperature difference, which are assumed to be constant over time, and the sound transmission through a slit is less than when the whole window is opened. The limitations of these devices for controlling airflow and noise are obvious.

[0004] The second b.2) is the closest to the proposed invention, although it has a narrower scope of application. These are ducts that direct the air flow through narrowings and changes of direction in order to control the air flow by blocking the flow, which is highly variable as it depends on the action of the wind and the temperature difference, which is why some of them have adjustable openings that are normally manually operated. The more complex ones include dampers with mechanisms that close at certain times when the air flow is very high. This difficulty in controlling the air flow is the main disadvantage, causing annoying draughts and energy losses. The same mechanism serves, with similar problems, to hinder the propagation of noise between zones, since changes of direction and narrowing imply loss of sound energy, which can be improved by placing materials with high acoustic absorption on some interior surfaces of the duct. It should be noted that the ease of airflow and sound absorption are inversely related, the higher the airflow the lower the sound absorption, so that difficulties in controlling one have an impact on the other. Finally, it should be noted that the manufacture of these devices in their most efficient mode, with changes of direction in the duct, point coatings for acoustic absorption, flow control dampers and manual opening regulation, is complex.Explanation of the invention

[0005] The proposed invention makes it possible to balance the composition of the air between separate zones (1) and with different environmental conditions, reducing heat transmission by convection and mixing of unnecessary components, as well as sound transmission. It differs from the above technical background in that it contains a section of the connecting duct (2) between zones is filled with one or more groups of granular material elements (3), requiring a different and simpler manufacturing system.

[0006] The material of the connecting duct can be any material suitable for air conduction, however, it is desirable that it is or is covered with insulating materials that reduce the transmission of heat and sound energy.

[0007] The granular material group is a collection of solid macroscopic particles that are large enough for the interaction force between them to be that of friction and which collectively exhibit properties similar to those of a solid or a fluid, depending on the type of forces to which it is subjected. As a fluid it can easily adapt the shape of its container and when confined it behaves like a solid, but since the particles do not fit together perfectly, voids are formed which are connected to each other forming a three-dimensional network of conduits which is characterised by properties called void ratio and permeability. Another important characteristic is that granular matter tends to dissipate kinetic energy quickly due to the frictional force between particles, so it can also absorb sound energy vibrations.

[0008] According to the above, the particles can be of any shape and material that as a group meet the above conditions such as sand, plastic granules, expanded clay, etc., however, there are certain properties such as thermal conductivity, heat capacity and acoustic absorption that, together with the particle size and shape, determine the final performance of a group of granular material, which together with the section of the duct and the length of the filled section provide values that for now are obtained empirically, and which are formalised in a specific design of the invention.

[0009] It is manufactured by simply filling a section of duct with the granular elements which, if the shape or position of the duct is suitable, can be made by direct pouring into the duct. If it is not, the ends of the section to be filled are provided with containment systems for granular material that allow air to pass through (6), such as grids, nets or perforated sheets, which are also poured from one end and then closed. Finally, it is installed in the separation wall between the zones (7).

[0010] It works as follows: Gases are fluids composed of different molecules that move freely and interact very little with each other, so the composition of gases within a compartment and at the same height tends to be homogeneous. If the components do not have very different atomic weights, and there is movement within the compartment that favours mixing, the height has no influence. The same is true for most aerosols. Consequently, when the air components in one zone communicate directly with those in another zone, they exchange components until they are equal in composition.

[0011] If the zones are at different temperatures, heat transfer also occurs with turbulent movements due to density differences, which we call convection; and which involve all the components; those in different proportions and those already in the same proportion. Since air is mainly composed of inert gases, 78% nitrogen, most of the gases that are moved, mixed and thermally conditioned in ventilation are not useful for their intended purpose, although they are the ones that require the most energy consumption to maintain the original temperature conditions.

[0012] The proposed invention reduces these effects. The air from the separate zones comes into contact through the connecting duct by passing through the section filled by the granular group, which is porous and permeable, thus allowing the exchange of components until their composition is equalised.

[0013] If the filled section is of adequate length, the influence of air movements and temperature differences between the zones is reduced by friction and heat exchange between the air and the particles. Thus, there are two sub-sections (4) on each side that function as dampers and a central one (5) in which the exchange takes place in a protected manner. Since the components that are in similar proportions in both zones have no differential partial pressure, they are displaced to a lesser extent. Consequently, heat transfer by convection and mixing of unnecessary components is reduced. The heat and sound transfer reduction provided is evaluated empirically for a given duct cross-section, filled section length and granular element.

[0014] There are variations that improve the effectiveness of the device, such as a widening of the central part of the duct occupied by the granular group with respect to the ends to increase the volume of the exchange subgroup, or the use of spherical shaped granular elements to provide a high void ratio.

[0015] It is also possible to incorporate environmental sensors that trigger a duct closure damper to prevent the process in the event of trying to evacuate a component from one area to another area where that component is already present in greater proportion. This would obviously not be possible since the resulting process would be contrary to the intended process. In general, this mechanism is useful to cancel any kind of exchange of unwanted components, and to resume it when conditions are suitable. It can also be done manually.

[0016] Because some air components may be trapped inside the device due to their density or because they condense into liquid, a drainage system can be incorporated. This can also be done with the shape and orientation of the duct.

[0017] Since there are components of indoor air that cannot be evacuated as quickly as necessary, such as biological agents, combustion fumes, human bioeffluents, etc., their use can be combined with other devices such as air purifiers, exhaust ducts, etc., thus integrating them into indoor environmental quality systems.

[0018] On the other hand, given that granular matter absorbs sound energy due to its capacity to dissipate kinetic energy, noise transmission between zones is reduced by a mechanism independent of that which allows the exchange of components, and whether this exchange is very high or nil is not influenced by the above-mentioned factors.

[0019] It is also possible to connect several zones by means of a branched or series duct.

[0020] Finally, it should be noted that it can be combined with multiple devices for user information on operation, sensory indicators, displays and data logging, with the necessary power supplies for operation.Brief description of the drawings

[0021] To complement the description being made and in order to assist in a better understanding of the features of the invention, in accordance with a preferred example of a practical embodiment of the invention, a set of figures is attached as an integral part of this description, in which the following is illustrated for illustrative purposes and without limitation: Figure 1 shows an external view of a possible realisation of the device according to the present invention with two zones and a granular group. Figure 2 shows the elements of the device shown in Figure 4 disassembled. Figure 3 shows a variant of the device shown in Figure 4 applied to three zones. Figure 4 shows an external view of a possible realisation of the device according to the present invention with two zones, three different granular material groups with flaring for the central group, environmental sensor, gate, and device for informing the user of the operation. Figure 5 shows the elements of the device shown in Figure 4 disassembled and viewed from the inside. Figure 6 shows the elements of the device shown in figure 4 disassembled and viewed from the outside. Figure 7 shows a cross-section of the device in figure 4. Figure 8 shows in the upper part an irregular granular group, in the middle part a granular group of spherical elements and in the lower part a granular group of spherical elements of similar size, showing the variation of the void ratio in each case. Figure 9 shows in the upper part a schematic realisation in accordance with the present invention in which a single granular group has been poured into the duct without the need for a containment system, and another schematic realisation is shown in the lower part in which containment systems for two different granular groups and complementary systems for aerosol decontamination have been included.

[0022] The following is a list of the various elements depicted in the figures comprising the invention: 1 = Separate zones with different environmental conditions 2 = Connecting duct between zones 3 = Granular group filling a section of the pipeline 4 = Granular end subgroup for damping of environmental conditions 5 = Central granular subgroup of component exchange 6 = Confinement system of granular elements 7 = Separation wall between zones with different environmental conditions 8 = Damper actuated by environmental sensor to regulate the duct closure 9 = Condensate and heavy air component drainage system. 10 = Aerosol retaining filter 11 = Electromagnetic wave emitter for aerosol decontamination 12 = Device for informing the user of operation Preferred embodiment of the invention

[0023] Figures 1 to 2 show a preferred embodiment of the invention for installation through a very thin wall separating an office from the access stairs, where the frequent opening of doors to the outside provides high air renewal, lower temperature and high noise level with respect to the offices. It contains a metal duct with a constant circular section, filled with glass spheres of uniform grain size close to the millimetre with a containment system at each end formed by a metal mesh with a smaller hole than the spheres.

[0024] Figure 3 shows a variant of the previous version to be installed through the walls between an area located in a hospital environment with ductwork for general ventilation and two other areas without ducts that use recirculating indoor air for biological decontamination. It contains a HEPA type filter on the metal mesh of these areas and a single branched duct filled with ceramic spheres of uniform granulometry close to a centimetre.

[0025] Figures 4 to 7 show a preferred embodiment of the invention for installation through a wall separating the interior from the exterior of a building in an urban area with high traffic. It contains a circular duct made of rigid plastic material with low thermal conductivity divided into three sections. One duct section is longer than the other two and has an inner diameter greater than the sum of the outer diameter of the other two. The smaller ducts are inserted inside the larger one and attached to opposite ends, which have metal covers with a gap coinciding with the free section of each smaller duct, thus resulting in a duct with a central widening. Each of the sections is filled with different granular elements to improve the effectiveness of the device. The larger duct is filled with expanded plastic spheres of similar diameter and approximately half a centimetre in diameter, as the main insulating body. The smaller ducts are also filled with spheres of similar diameter, but the inner side is filled with ceramic spheres to reduce convection losses, and the outer side with porous expanded clay spheres to reduce noise transmission. It has a damper for closing the duct on the outside environment side, which is activated by sensors for high levels of urban traffic pollution, and a device for informing the user of the operation with environmental sensors, display and acoustic indicator of inadequate levels in the composition of the air.Industrial application

[0026] The proposed invention can be implemented by a person skilled in the art and applied to different models providing particular performance capabilities.

Claims

1. Device for balancing the air composition between two or more separate zones (1) with different environmental conditions, which contains a duct (2) connecting the zones with each other, characterised by a group of granular elements (3) that completely fills a section of said duct in a length related to the type of granular element used and the final performance provided in terms of substance, heat and sound exchange, which are obtained empirically.

2. Device for balancing the air composition according to claim 1, which contains spherical shaped granular elements.

3. Device for balancing the air composition according to claim 2, which contains granular elements of spherical shape and same size.

4. Air composition balancing device according to any one of the preceding claims which contains two or more duct sections filled by groups of granular elements.

5. Air composition balancing device according to any one of the preceding claims, which contains widening in the duct.

6. Device for balancing the air composition according to claim 5, which contains a widening in the duct manufactured with three ducts, one of which is longer than either of the other two and also has an inside diameter greater than the sum of the outside diameter of the other two, so that the smaller ducts are inserted into the larger one and are attached to opposite ends, which have covers for the larger duct with a gap coinciding with the free section of each smaller duct. Figures 4 to 7.

7. Device for balancing the air composition according to any one of the preceding claims, wherein the position of the granular elements of a group is kept stable by means of an external confinement system (6) with perforations that allow the passage of air but not of the granular elements.

8. Device for balancing the air composition according to any one of the preceding claims 1 to 6, wherein the position of the granular elements of a group is kept stable by a binder between the elements.

9. Device for balancing the air composition according to any one of the preceding claims, which contains one or more dampers able to partially or completely close the duct.

10. Device for balancing the air composition according to claim 9, which contains a one or more environmental sensors that automatically trigger the opening or closing of the duct.

11. Device for balancing the air composition according to any one of the preceding claims, which contains a drainage system (9) for condensate and heavy air components.

12. Device for balancing the air composition according to any one of the preceding claims, which contains an aerosol retaining filter (10).

13. Device for balancing the air composition according to any one of the preceding claims, which contains an electromagnetic wave emitter (11) with a wavelength suitable for aerosol decontamination.

14. Device for balancing the air composition according to any one of the preceding claims, which is integrated into other devices for improving indoor environmental quality.

15. Device for balancing the air composition according to any one of the preceding claims, which contains a device that provides information to the user about the operation by means of one or more visual indicators, acoustic indicators, displays, data loggers, and environmental sensors, with power supplies necessary for its operation.

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