EP2129984A2

EP2129984A2 - Apparatus for drying materials, particularly zeolites or the like

Info

Publication number: EP2129984A2
Application number: EP08719133A
Authority: EP
Inventors: Alessandro Bozzoli; Guido Cicolini; Giordano Contin; Francesco Fontana; Luca Pomari
Original assignee: Kloben Sas Di Turco Adelino E C
Current assignee: Fondazione Bruno Kessler
Priority date: 2007-02-13
Filing date: 2008-02-13
Publication date: 2009-12-09
Also published as: WO2008099262A3; WO2008099262A2; ITMO20070046A1

Abstract

The apparatus (1) for drying materials, particularly zeolites or the like, comprises heating means (2) for heating a gaseous fluid, wherein the heating means (2) have a solar collector crossed by the fluid, and conveyor means (3) suitable for bringing the heated fluid into contact with the surface of a material suitable for the adsorption of the humidity of a gaseous mix.

Description

APPARATUS FOR DRYING MATERIALS, PARTICULARLY ZEOLITES OR THE LIKE.

Technical Field

The present invention relates to an apparatus for drying materials, particularly zeolites or the like. Background Art

In the field of air-conditioning in homes, industries and public places, the use is known of heat pumps suitable for heating or cooling the environments in which the temperature is to be regulated to bring it to desired values. The fast growing demand for constant climatic comfort has in fact produced a substantial increase in the use of air-conditioning devices. Traditional compression devices operate with electricity, exploiting the refrigeration effect produced by the condensation/evaporation of a coolant fluid, typically gaseous, to cool the air to be introduced into air-conditioned environments.

These compression devices can if necessary operate like heat pumps, thereby also heating the building during the cold months.

Compression systems do however have a number of drawbacks. In fact, the energy consumption required to make the compression system work is very high and is very costly for the user.

Furthermore, the gas used in these systems often has a fairly strong impact on the environment, calling for skilled labour to dispose of the appliances no longer used.

Also known is the use of adsorption air-conditioning systems which exploit the characteristic of a number of porous materials to exothermally absorb on their surface a number of molecules, in particular water vapour, such as zeolites, silica, active charcoals, rocks (diatomite, montmorillonite, etc.), calcium (oxides, sulphates, etc.), synthetic compounds which act as molecular sieves, and others. These air-conditioning systems can operate in two modes: cooling and heating. In both the modes, the adsorption of the water vapour on zeolites involves a saturation of the active surface, and therefore a loss of functionality; the surface must therefore be regenerated before a new cycle can start.

Traditional regeneration comprises the use of electric devices or fuel devices suitable for heating a flow of air passing over the porous material, desorbing the water vapour.

Once the trapped humidity has been removed, the zeolites can be used again in a new cycle.

The adsorption air-conditioning systems do however have a number of drawbacks.

In fact, the regeneration of the zeolites occurs through the use of traditional heating sources which eliminate the advantages produced by the adsorption, meaning the obtaining of low-cost clean energy.

To overcome this drawback, the coupling is known of the adsorption systems on porous material with thermal solar panels in which circulates a thermo- vector liquid used to heat the water inside a tank.

The hot water is then used, not only for domestic purposes, but also to heat the flow of air used to dry, and therefore regenerate, the porous material.

This solution also has its drawbacks, as it requires the integration of a sufficiently-sized tank associated with the solar panels, with a consequent increase in the costs of installation, labour and maintenance; furthermore, the installation of a tank in structures or buildings which have not been pre- prepared can be very complex whenever the necessary space is not available.

A second drawback is tied to the large quantity of heat required to bring the water in the tank to an optimum operating temperature: in case of bad weather, the inevitable heat dispersions cause the water to cool quickly and before this can be used for the regeneration phase, the absorption is required of large quantities of thermal energy.

Another drawback is associated with the fact that the higher the temperature of the flow of air passing over the surface of the zeolites, the quicker and more efficient the desorption of the humidity from the zeolites; inevitably, the use of a water tank places strong limits to this temperature, depending on the quantity of solar energy available and on the boiling point of the water, making the drying process slow and not very efficient. Object of the Invention

The main aim of the present invention is to provide an apparatus for drying materials, particularly zeolites or the like, that is able to operate in a cost- effective way, while at the same time ensuring efficient operation over a long period of time.

Another object of the present invention is to find an apparatus that is totally environment friendly, using only renewable energy sources and without the emission of combustion produced gases.

Yet another object of the apparatus according to the invention is to eliminate dependence on a water heating tank, thereby permitting a reduction in installation costs. Another object of the present invention is to provide an apparatus that allows to overcome the mentioned drawbacks of the known technique within the ambit of a simple and rational solution, which is easy and effective to use, as well as having a low cost.

The above objects are all achieved by the present apparatus for drying materials, particularly zeolites or the like, which comprises heating means for heating a substantially gaseous fluid, conveyor means suitable for bringing said heated fluid into contact with the surface of at least a material suitable for the adsorption of the humidity of a gaseous mix, characterized by the fact that said heating means comprise at least one solar collector crossed by said fluid. Brief Description of the Drawings Further characteristics and advantages of the present invention will appear more evident from the description of a preferred, but not exclusive, embodiment of an apparatus for drying materials, particularly zeolites or the like, illustrated indicatively by way of non limiting example in the accompanying drawings, wherein: figure 1 is a view of an apparatus for drying materials according to the invention joined to a thermal conditioning system operating in a first operating mode; figure 2 is a view of an apparatus for drying materials according to the invention joined to a thermal conditioning system operating in a second operating mode. Embodiments of the Invention

With particular reference to such figures, an apparatus for drying materials, particularly zeolites or the like, has been globally indicated by 1.

The apparatus 1 comprises heating means 2 for heating a gaseous fluid and conveyor means 3 suitable for bringing the heated fluid into contact with the surface of the material to be dried. Usefully, the material to be dried is suitable for selectively adsorbing the humidity from a gaseous mix, such as, e.g., environment air.

The materials suitable for this purpose are zeolites, silica, active charcoals, rocks (diatomite, montmorillonite, etc.), compounds containing calcium (oxides, sulphates, etc.), synthetic compounds which act as molecular sieves, and others that have a micro-porosity adequate for the adsorption of at least one fraction of the gaseous mix with which they are placed in contact and with the contemporaneous freeing of heat.

The heating means 2 consist in a solar collector in which circulates the fluid used for drying; other embodiments cannot however be ruled out in which the apparatus 1 uses a plurality of solar collectors. Advantageously, the gaseous fluid used for drying is air.

The solar collector 2 is of the pipe type and is therefore made up of a plurality of tubular elements 4 inside which the fluid flows; these elements comprise, in particular, a surface exposed to the sun and suitable for exchanging the heat obtained by irradiation with the fluid passing inside. Alternatively, the solar collector 2 can be of the flat type, with glazed or unglazed surfaces, with vacuum pipes, or in any other alternative embodiment suitable for heating a substantially gaseous fluid.

The apparatus 1 also comprises a first container 5 and a second container 6, each containing the material to be dried and associated with the conveyor means 3; for a person expert in the sector, using just one or a plurality of containers, alternatively or in addition to the pair of containers 5 and 6 will prove straightforward. Usefully, inside the first container 5 and the second container 6 the material to be dried is arranged so as to expose as large a surface as possible to the passing air flow and thus optimise both drying and adsorption.

Both the first container 5 and the second container 6 are associated with a thermal conditioning system 7 suitable for cooling and heating domestic or industrial environments and domestic hot water or for similar uses. The conveyor means 3 comprise an air inlet duct 8 used for drying inside the solar collector 2, ventilation means 9 suitable for moving the air along the conveyor means 3 and filtering means 10 for filtering the inflowing air. The ventilation means 9 and the filtering means 10 consist of a fan and a filter respectively arranged on the inlet duct 8.

Downstream of the solar collector 2 with respect to the direction of flow of the fluid, a distribution duct 1 1 is arranged suitable for connecting the solar collector 2 with the first container 5 and the second container 6 in a fluid way. The distribution duct 1 1, in particular, divides into a first branch 12 and into a second branch 13 for the fluidic connection with the first container 5 and the second container 6 respectively.

The conveyor means 3 further include selective control means 14 for controlling the flow of the fluid used for drying, suitable for alternatively defining two work configurations.

In the first work configuration, the first container 5 is in fluidic connection with the solar collector 2, while the second container 6 is in fluidic connection with the thermal conditioning system 7; in the second work configuration, on the other hand, the first container 5 is in fluidic connection with the thermal conditioning system 7, while the second container 6 is in fluidic connection with the solar collector 2.

The selective control means 14 are composed of a first valve element 15 and of a second valve element 16 located on the first branch 12 and on the second branch 13 respectively; other embodiments cannot however be ruled out where the control means are composed of a single valve upstream of the first branch 12 and of the second branch 13 suitable for controlling the opening or the closing of the first branch 12 or of the second branch 13. Figure 1 shows the operation of the apparatus 1 in the first work configuration and of the thermal conditioning system 7 used to cool environments and to heat domestic hot water or the like.

The fluid used for drying, in the illustrations, environment air, enters the inlet duct 8 and is pushed by means of the ventilation means 9; subsequently it is filtered by the filtering means 10, before entering the solar collector 2.

Flowing close to the irradiated surfaces of the solar collector 2, the air acquires thermal energy and heats up.

Through the distribution duct 1 1, the heated fluid reaches the first branch 12 and the second branch 13.

The selective control means 14 are positioned so the first container 5 is placed in fluidic connection with the solar collector 2, while the second branch 13 is obstructed.

The heated air therefore flows only through the whole of the first branch 12 and enters the first container 5.

The heated fluid, coming into contact with the material to be dried, desorbs the water molecules adsorbed in the porous structure causing the latter to dry and therefore regenerate.

Usefully, after being used for drying, the fluid used for drying coming out of the first container 5 is conveyed, through a valve 17, to a system of valves 18 which controls its entry into a first hot exchanger 19 where the fluid yields the residual heat to domestic water or the like.

The second container 6 on the other hand is fluidically connected to the thermal conditioning system 7. The thermal conditioning system 7 comprises an inlet channel 20 for the environment air, on which are located a filter 21 and a fan 22.

Through a three-way valve 23, the environment air from the inlet channel 20 is directed to the second container 6 containing the dry material and suitable for adsorbing the water vapour in the air. The dehumidified air coming out of the second container 6 is therefore hot and dry and is conveyed, through the second valve element 16, first into an air/air heat exchanger 24 where it is cooled, and then into an evaporator 25 where it is humidified and further cooled.

Coming out of the evaporator 25, the cold air passes through the valve 26 and enters a cold exchanger 27 in which circulates the thermovector means to be cooled, e.g., air, water or the like; this means is then used to cool the environments.

The air coming out of the cold exchanger 27 passes through the valve 28 and is again conveyed to the air/air heat exchanger 24 where it is heated.

By passing through the valve system 18, the air reaches the first hot exchanger 19, where it yields the thermal energy acquired in the air/air heat exchanger 24.

As an expert in the sector can easily appreciate, by operating on the valves 17,

23 and 26 together with the first valve element 15 and second valve element 16 the first work configuration can be switched with the second and the first container 5 can thus be placed in fluidic connection with the thermal conditioning system 7 and the second container 6 in fluidic connection with the solar collector 2.

Similarly, different operating modes can be obtained of the thermal conditioning system 7 by simply modifying the path of the air flow circulating inside it.

Figure 2, for example, shows the operation of the apparatus 1 in the first work configuration and of the thermal conditioning system 7 used to heat domestic hot water or the like and to heat environments.

The operation of the apparatus 1 is the same as that shown in figure 1 and permits drying the material contained in the first container 5 and heating domestic hot water inside the first hot exchanger 19. Unlike the operating model in figure 1, on the other hand, the environment air entering the inlet channel 20 through the operation of the fan 22 and passing through the filter 21, is deviated into the valve 28 and then into the evaporator

25, where it is humidified and cooled.

Exiting from the evaporator 25, the air enters the air/air heat exchanger 24 where it is preheated, and from here, through the second valve element 16, it is directed to the second container 6 containing the dry material suitable for adsorbing the water vapour in the air. The air coming out of the second container 6 is therefore hot and dry, and after passing through the valve 23 and the valve system 18 is conveyed directly to a second hot exchanger 29, where it yields the thermal energy acquired in the second container 6 to another heat transfer means. The heat transfer means is easy to use for heating domestic or industrial environments.

Advantageously, the air coming out of the second heat exchanger is already dry and filtered and can therefore be used as air supply entering the solar collector 2. In the same way as the operating mode shown in figure 1, it is straightforward for a person in the sector to switch the apparatus 1 and the thermal conditioning system 7 from the first to the second work configuration by simply intervening on the valves 17 and 23 together with the first valve element 15 and the second valve element 16. It has in point of fact being ascertained how the described invention achieves the proposed objects.

In particular, the fact is underlined that the use of a solar collector to regenerate the porous material permits obtaining a heating/cooling apparatus that fully exploits the renewable energy sources. Furthermore, the elimination of the tank traditionally associated with the solar collectors, made possible by exploiting a gaseous fluid, permits increasing the efficiency of the apparatus and eliminating the various problems tied to the presence of a tank, such as overall dimensions, installation and maintenance costs, energy dispersion, numerous heat exchanges between the apparatus elements, high heat inertia and low obtainable temperatures.

The invention thus conceived is susceptible to numerous modifications and variations, all of which falling within the scope of the inventive concept. Furthermore all the details can be replaced with others that are technically equivalent. In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements without because of this moving outside the protection scope of the following claims.

Claims

1) Apparatus for drying materials, particularly zeolites or the like, which comprises heating means for heating a substantially gaseous fluid, conveyor means suitable for bringing said heated fluid into contact with the surface of at least a material suitable for the adsorption of the humidity of a gaseous mix, characterized by the fact that said heating means comprise at least one solar collector crossed by said fluid.

2) Apparatus according to claim 1 , characterized by the fact that said collector is of the pipe type. 3) Apparatus according to one or more of the preceding claims, characterized by the fact that said collector is of the flat type.

4) Apparatus according to one or more of the preceding claims, characterized by the fact that said solar collector comprises at least one tubular element inside which said fluid flows and having a surface that can be irradiated by an irradiation source and suitable for exchanging the heat with said fluid.

5) Apparatus according to one or more of the preceding claims, characterized by the fact that it comprises at least a first container containing said material and associable with said conveyor means.

6) Apparatus according to one or more of the preceding claims, characterized by the fact that it comprises at least a second container containing said material and associable with said conveyor means.

7) Apparatus according to one or more of the preceding claims, characterized by the fact that at least one of said containers is associated with a thermal conditioning system, suitable for cooling/heating environments, domestic hot water or the like.

8) Apparatus according to one or more of the preceding claims, characterized by the fact that said first and second containers are both associated with said system.

9) Apparatus according to one or more of the preceding claims, characterized by the fact that said conveyor means comprise an inlet duct for said fluid inside said solar collector.

10) Apparatus according to one or more of the preceding claims, characterized by the fact that said conveyor means comprise ventilation means suitable for moving said fluid.

1 1) Apparatus according to one or more of the preceding claims, characterized by the fact that said ventilation means are arranged on said inlet duct. 12) Apparatus according to one or more of the preceding claims, characterized by the fact that said conveyor means comprise filtering means suitable for filtering said fluid.

13) Apparatus according to one or more of the preceding claims, characterized by the fact that said filtering means are arranged on said inlet duct. 14) Apparatus according to one or more of the preceding claims, characterized by the fact that said conveyor means comprise at least one distribution duct of said fluid located downstream of said solar collector.

15) Apparatus according to one or more of the preceding claims, characterized by the fact that said conveyor means comprise at least a first branch for the fluidic connection placed in between said distribution duct and said first container.

16) Apparatus according to one or more of the preceding claims, characterized by the fact that said conveyor means comprise at least a second fluidic connection branch placed in between said distribution duct and said second container.

17) Apparatus according to one or more of the preceding claims, characterized by the fact that said conveyor means comprise selective control means for controlling the flow of said heated fluid suitable for positioning said first container and said second container alternatively in a first work configuration wherein said first container is in fluidic connection with said solar collector and said second container is in fluidic connection with said system, and in a second work configuration, wherein said first container is in fluidic connection with said system and said second container is in fluidic connection with said solar collector. 18) Apparatus according to one or more of the preceding claims, characterized by the fact that said selective control means comprise at least a first valve element, located on said first fluidic connection branch. 19) Apparatus according to one or more of the preceding claims, characterized by the fact that said selective control means comprise a second valve element, located on said second fluidic connection branch.

20) Apparatus according to one or more of the preceding claims, characterized by the fact that said heating means comprise a plurality of solar collectors.

21) Apparatus according to one or more of the preceding claims, characterized by the fact that said material is chosen among zeolites, silica, active charcoals, rocks, calcium compounds, synthetic compounds which act as molecular sieves, etc.. 22) Method for drying a material, particularly zeolites or the like, which comprises heating a substantially gaseous fluid, bringing said fluid into contact with a material, suitable for the adsorption of the humidity of a gaseous mix, characterized by the fact that said heating comprises the crossing of said fluid in a solar collector.