HEAT RECOVERY ADSORBER AS VENTILATION SYSTEM IN BUILDINGS

Abstract

The invention relates to a ventilation system (10) with heat recovery adsorber, the ventilation system (10) for being installed in buildings, wherein the ventilation system (10) furthermore comprises at least one exterior intake/outlet opening (11) for an air stream from outside of the building and at least one interior intake/outlet opening (23) for an air stream from inside the building, at least one air fan unit (14) and at least one filter unit (12, 22), wherein the heat recovery adsorber includes a heat exchange material (16) for absorbing and releasing heat from the air streams and a sorption material (18) for at least adsorbing and desorbing at least one sorbate from the air streams, wherein the at least one sorbate is water vapor, said sorption material (18) comprising at least one adsorbent for water vapor exhibiting an s-shaped water adsorption isotherm (30) at room temperature (25 C.+/10 C.) with a steep increase in a narrow relative humidity range, wherein a main loading lift of the adsorbent for water vapor occurs in the relative humidity range from 0.1 to 0.5 and the saturation capacity of the adsorbent for water vapor lies in the range from 0.25 to 1.2 kg.sub.water/kg.sub.adsorbent. The invention further relates to methods and uses for combined heat recovery, cooling/heating and dehumidifying/humidifying of air streams for buildings as well as such buildings.

Claims

1.-16. (canceled)

17. A ventilation system (10) with heat recovery adsorber, the ventilation system (10) for being installed in buildings, wherein the ventilation system (10) furthermore comprises at least one exterior intake/outlet opening (11) for an air stream from outside of the building and at least one interior intake/outlet opening (23) for an air stream from inside of the building, at least one air fan unit (14) and at least one filter unit (12, 22), wherein the heat recovery adsorber includes a heat exchange material (16) for absorbing and releasing heat from the air streams and a sorption material (18) for at least adsorbing and desorbing at least one sorbate from the air streams, wherein the at least one sorbate is water vapor, said sorption material (18) comprising at least one adsorbent for water vapor exhibiting an s-shaped water adsorption isotherm (30) at room temperature (25 C.+/10 C.) with a steep increase in a narrow relative humidity range, wherein a main loading lift of the adsorbent for water vapor occurs in the relative humidity range from 0.1 to 0.5 and the saturation capacity lies in the range from 0.25 to 1.2 kg.sub.water/kg.sub.adsorbent.

18. The ventilation system (10) according to claim 17, wherein the steep increase of the water adsorption isotherm (30) is in the relative humidity range from 0.15 to 0.4.

19. The ventilation system (10) according to claim 17, wherein the saturation capacity of the adsorbent for water vapor lies in the range from 0.3 to 0.6 kg.sub.water/kg.sub.adsorbent.

20. The ventilation system (10) according to claim 17, wherein the loading lift is at least 65% of the total loading.

21. The ventilation system (10) according to claim 17, wherein the adsorbent for water vapor is selected from the group consisting of silica gels, activated alumina, activated bauxite, molecular sieves and metal-organic frameworks (MOFs).

22. The ventilation system (10) according to claim 17, wherein the sorption material (18) is provided as pulverulent material, granulates, shaped bodies or monoliths and arranged in a casing as a matrix or a filling such as a packed bed or a moving bed and preferably as monolith.

23. The ventilation system (10) according to claim 17, wherein the sorption material (18) is deposited as a coating on a substrate, preferably made of ceramic, metal, plastic, foam based on polyurethane, polypropylene, polyester, metal or ceramic, woven or non-woven fibers of plastic, cellulose or mixtures thereof.

24. The ventilation system (10) according to claim 17, wherein the sorption material (18) is a metal-organic framework (MOF), preferably as aluminum fumarate MOF.

25. The ventilation system (10) according to claim 17, wherein the heat exchange material (16) is selected from the group consisting of ceramic or brick pieces, stone or fired clay gravel or pebbles, fired pellets of iron or other suitable high thermal capacity pelletized materials, conventional ceramic, metal or plastic packing of different shapes, corrugated metal and wire mesh.

26. The ventilation system (10) according to claim 17, wherein the heat exchange material (16) is provided as a honeycomb-structure.

27. The ventilation system (10) according to claim 23, wherein the coating comprises aluminum fumarate MOF deposited on a ceramic substrate.

28. The ventilation system (10) according to claim 17, wherein the sorption material (18) further comprises a sound-absorbing sorbent (20).

29. The ventilation system (10) according to claim 17, wherein the ventilation system (10) is provided as a decentralized unit, preferably installed in separated rooms of the building or as a centralized unit, installed in the building, wherein air from inside of the building is led to the interior intake/outlet opening (23) and the exterior intake/outlet opening (11) is arranged on an envelope of the building.

30. A method for combined heat recovery, cooling/heating and dehumidifying/humidifying air streams for buildings comprising the step passing indoor and/or outdoor air streams through a ventilation system (10) according to claim 17, wherein from the air streams heat and water vapor are regulated by the heat recovery adsorber.

31. A building having a ventilation system (10) according to claim 17.

32. Method of using a ventilation system (10) according to claim 17 for combined heat recovery, cooling/heating and dehumidifying/humidifying of air streams for buildings.

Description

[0042] Exemplary embodiments of the invention are illustrated in the figures and are explained in greater details in the following description.

[0043] In the figures:

[0044] FIG. 1 shows an embodiment of a ventilation system with a heat recovery adsorber according to the invention;

[0045] FIG. 2 shows another embodiment of a ventilation system with a heat recovery adsorber according to the invention;

[0046] FIG. 3 shows water adsorption isotherms of a preferred adsorbent for water vapor BASOLITE A520 used in an embodiment of a combined ventilation system according to the invention 298 K.

[0047] Referring to drawings, FIG. 1 shows a ventilation system 10 with a heat recovery adsorber in one preferred embodiment of the invention intended to be used in buildings, i.e. industrial, commercial and residential buildings, houses and mobile homes. As schematically indicated in FIG. 1 the ventilation system 10 comprises from outside to the inside of the building the following components: an exterior intake/outlet opening 11, a first filter unit 12, i.e. a dust filter, a air fan unit 14, for example a reversible air fan unit, heat exchange material 16, sorption material 18, sound-absorbing sorbent 20, a second filter unit 22 and an interior intake/outlet opening 23. In FIG. 1 a controller unit to control the rotation and direction of an electric motor operating the reversible air fan unit is not shown.

[0048] The reversible air fan unit 14 includes a housing attached to the following components, an axial type propeller and a reversible electric motor secured to the housing

[0049] When the air fan propeller rotates in one direction fresh air from the outside is sucked in and flows through the first filter unit 12, the following heat exchange material 16, sorption material 18, in the shown embodiment sound-absorbing sorbent 20 and the second filter unit 22, when it rotates in the opposite direction it forces the exhaust air from inside through the ventilation system to outdoor. Using a controller with the reversible air fan unit 14 the directions of the rotation can be reversed in equal time intervals, therefore the flow of the two air streams through the ventilation system 10 is periodic, countercurrent and balanced.

[0050] The ventilation system 10 comprises in the embodiment shown in FIG. 1 the first filter unit 12 and the second filter unit 22. According to a preferred embodiment the first filter unit 12 is a conventional filter for cleaning the incoming air from pollutants, dust, particulate matters and of odors etc. The second filter unit 22 may comprise a filter material to clean the air stream from pollens. Building filters typically employ activated impregnated carbons for the removal of pollutants, i.e. toxic chemicals. In filter units a sorbent is housed in a structure such that the toxic gas stream passes through a packed bad, monolith or volume such that the toxic gas contacts the sorbent and is removed by physical adsorption and/or chemical reaction.

[0051] According to the embodiment shown in FIG. 1 the heat exchange material 16, the sorption material 18 and the sound-absorbing sorbent 20 are arranged in separated components which are connected to one another in an appropriate way. The heat exchange material 16 is provided as a matrix in a casing with an opening for intake of exhaust air and an opening for outdoor fresh air and an opening for discharge of the exhaust air and for discharge of the fresh air. The matrix may include a single bed of solids or preferably a monolithic structure. Depending on the application, the matrix may include heat exchange material 16 such as ceramics.

[0052] The sorption material 18 includes at least an adsorbent for water vapor suitable for adsorbing moisture from the incoming fresh outdoor air wherein the water adsorption isotherm 30 of the adsorbent shows the characteristic s-shape form. During a sorption period the moisture from the incoming fresh outdoor air is adsorbed and is transferred into the exhaust air during desorption period. Furthermore moisture form exhaust air may adsorb on the adsorbent for water vapor and may desorb into incoming cool air. Said adsorbent for water vapor can be provided in different forms, alone or together with other sorbents of the sorption material 18. The sorption material 18 may be used as loose materials or as shaped bodies. The preferred metal-organic framework (MOF) may be used in form of granulates, shaped bodies or monolith. It is likewise to use mixtures of metal-organic framework (MOE) and other sorbents such as activated carbon, wherein mixtures of shaped bodies may be used too. The geometries of the shaped bodies are not subject to any restrictions. For example, possible shapes are, inter alia, pellets, pills, spheres, granules and extrudate such as rods, honeycombs, grids or hollow bodies. The sorption material 18 may be provided as monolith or in form of granulates attached to a substrate, for example a film permeable to air. The sorption material 18 may be provided as coating on a substrate or support. Furthermore the sorption material 18 may be provided as a matrix, including a heater for example in the form of heating wires.

[0053] The sound-absorbing sorbent 20 may include a noise-absorbing material, for example in the form of monolithic thermoplastic foam.

[0054] Since heat exchange material 16, sorption material 18 and sound-absorbing sorbent 20 may include structures or solids the preferred overall pressure drop has to be in the range of 1 mbar to 100 mbar.

[0055] Referring to FIG. 2, another embodiment of the ventilation system 10 with heat recovery adsorber is shown. In this embodiment the numbers of the comprised components are reduced by integrating different functions of the ventilation system 10 in a combined component 24. According to FIG. 2 the heat exchange material 16, the sorption material 18 and the sound-absorbing sorbent 20 are combined. Said combined component 24 may include the heat exchange material 16 provided as a matrix of ceramics and coated with the sorption material 18, for example the adsorbent for water vapor and/or the sound-absorbing sorbent 20. Furthermore, said combined component 24 may include monoliths, wherein a part is coated with a sound-absorbing sorbent 20 and another part is coated with the adsorbent for water vapor such as MOF, i.e. BASOLITE A520.

[0056] Referring to FIG. 3, a water adsorption isotherm of the preferred adsorbent for water vapor BASOLITE A520 is shown. The x-coordinate 26 represents the relative humidity, which is defined by the ratio of the partial pressure of water vapor to the saturation pressure of water vapor at the same temperature. The y-coordinate 28 represents the excess-uptake of the adsorbent for water vapor expressed in kg.sub.water/kg.sub.adsorbent. The preferred adsorbent BASOLITE A520, based on aluminum fumarate MOF, exhibits typically s-shaped water adsorption isotherm 30 recorded at 298 K. The isotherm 30 shows in the relative humidity range <0.15 less adsorption, i.e. preferably less than approximately 0.10 kg.sub.water/kg.sub.adsorbent, and the favorable steep increase in a narrow region of the relative humidity from 0.15 to 0.4. The water uptake in this relative humidity range is approximately 80% of the total loading. The isotherm 30 reaches a saturation plateau with less pronounced adsorption in the relative humidity range >0.4, wherein the additional water uptake is in the range from 0.05 to 0.15 kg.sub.water/kg.sub.adsorbent. The total water uptake at 100% humidity for the preferred adsorbent for water vapor BASOLITE A520 is approximately 0.55 kg.sub.water/kg.sub.adsorbent.