Air-conditioning method and device

Abstract

The invention relates to an air conditioning apparatus including a first absorptive heat exchanger having sorption channels in at least one flow direction, a method for conditioning fluids, in particular for cooling and/or drying a stream of air, an adsorptive air-air cross-flow heat exchanger, and an outer wall element including an integrated air conditioning apparatus.

Claims

1. An absorptive air-air cross-flow heat exchanger, wherein the channels of the heat exchanger have no internal fins, wherein the heat exchanger has sorption channels having a channel width of from 0.5 to 2 mm, the sorption channels coated with an adsorption material in at least one flow direction, the adsorption material comprising water-adsorbing metal-organic frameworks, wherein a coating thickness of the adsorption material in the sorption channels is from 10 to 200 μm, and heat exchanger channels in at least one other flow direction, wherein an amount of an adsorption material coated in the heat exchanger channels is less than 5% of an amount of the adsorption material coated in the sorption channels.

2. The absorptive air-air cross-flow heat exchanger according to claim 1, wherein the heat exchanger channels have no adsorption material.

3. The absorptive air-air cross-flow heat exchanger according to claim 1, wherein the channel width of the sorption channels is from 0.7 to 1.5 mm.

4. The absorptive air-air cross-flow heat exchanger according to claim 1, wherein the coating thickness of the adsorption material in the sorption channels is from 20 to 150 μm.

5. A process for conditioning a fluid, which comprises the following steps: (a) flow of the process fluid through the sorption channels of a first absorptive heat exchanger, (b) drying of the process fluid in the first absorptive heat exchanger, (c) flow of the dried process fluid to the cold side of a cold source, (d) cooling of the dried process fluid in a cold source, (e) flow of the dried and cooled process fluid into the region to be conditioned, (f) parallel flow of the regeneration fluid through the heat exchanger channels of the first absorptive heat exchanger, (g) uptake of the heat of adsorption by the regeneration fluid, (h) flow of the heated regeneration fluid to the hot side of a heat source, (i) further heating of the regeneration fluid in the heat source, (j) flow of the heated regeneration fluid through the sorption channels of a second absorptive heat exchanger, (k) vaporization of the adsorbates located in the second absorptive heat exchanger and uptake of these adsorbates by the regeneration fluid, (l) flow of the moist regeneration fluid into an exterior region; wherein at least one of the first absorptive heat exchanger and the second absorptive heat exchanger is the absorptive air-air cross-flow heat exchanger of claim 1.

6. The process according to claim 5, wherein exhaust air from the region to be conditioned is used as regeneration fluid.

7. The process according to claim 5, wherein the process is operated cyclically.

8. The process according to claim 5, wherein the steps (a) to (l) and the cooling of the second absorptive heat exchanger are followed by the following steps: (m) optional interruption of the flow of the process fluid and of the regeneration fluid in the first adsorptive heat exchanger, should this not yet have taken place, (n) flow of the process fluid through the sorption channels of a second absorptive heat exchanger, (o) drying of the process fluid in the second absorptive heat exchanger, (p) flow of the dried process fluid to the cold side of a cold source, (q) cooling of the dried process fluid in a cold source, (r) flowing of the dried and cooled process fluid into the region to be conditioned, (s) parallel flow of the regeneration fluid through the heat exchanger channels of the second absorptive heat exchanger, (t) uptake of the heat of adsorption by the regeneration fluid, (u) flow of the heated regeneration fluid to the hot side of a heat source, (v) further heating of the regeneration fluid in the heat source, (w) flow of the heated regeneration fluid through the sorption channels of a first absorptive heat exchanger, (x) vaporization of the adsorbates located in the first absorptive heat exchanger and uptake of these adsorbates by the regeneration fluid, (y) flow of the moist regeneration fluid into an exterior region.

9. The process according to claim 5, wherein, as heat source or cold source, heat pumps based on compressor plants are used.

10. The process according to claim 5, subsequently comprising a further step: cooling of the second absorptive heat exchanger.

11. The process according to claim 10, wherein the cooling of the second absorptive heat exchanger is achieved by means of the regeneration fluid for the second heat exchanger, the conditioned process fluid and/or the exterior air flowing through the heat exchanger.

12. An air conditioning apparatus for conditioning a fluid, comprising a first absorptive heat exchanger, which has sorption channels in at least one flow direction and has heat exchanger channels in at least one flow direction, a heat-cold source for the removal of heat arranged downstream of the first absorptive heat exchanger in the flow direction of the sorption channels, a heat-cold source for the uptake of heat arranged downstream of the first absorptive heat exchanger in the flow direction of the heat exchanger channels and a second absorptive heat exchanger, which is arranged downstream of the heat-cold source for the uptake of heat and has sorption channels in at least one flow direction and has heat exchanger channels in at least one flow direction, where the sorption channels on the second heat exchanger are arranged in the flow direction of the heat exchanger channels of the first heat exchanger; wherein at least one of the first absorptive heat exchanger and the second absorptive heat exchanger is the absorptive air-air cross-flow heat exchanger of claim 1.

13. The air conditioning apparatus according to claim 12, wherein the heat exchangers and the heat-cold sources are connected via rigid pipes and/or movable hoses.

14. The air conditioning apparatus according to claim 12, wherein the apparatus does not comprise any rotating components.

15. The air conditioning apparatus according to claim 12, wherein elements which fan out and/or laminarize the airflow are inserted upstream of the heat exchangers.

16. The air conditioning apparatus according to claim 12, wherein the adsorption material has a density of from 0.2 to 2 g/cm.sup.3 and metal-organic frameworks and/or modified carbon are used as adsorption material in the sorption channels.

17. The air conditioning apparatus according to claim 12, wherein BASOLITE® A520, MIL-160, MOF-841, U10-66, DUT-67 and/or MOF-801 are used as adsorption material in the sorption channels.

18. An outer wall element comprising an air conditioning apparatus according to claim 12.

Description

(1) FIG. 1: Abstracted structure of the air conditioning apparatus

(2) The following abbreviations are used in FIG. 1: OL Exterior air KL Conditioned air IL Interior air AL Exhaust air 10 Absorber heat exchanger 1 11 Absorber heat exchanger 2 20 Heat pump 21 Hot pole of the heat pump 22 Cold pole of the heat pump 23 Drive energy for the heat pump

(3) FIG. 2: Structure of the air-air cross-flow heat exchanger

(4) The following abbreviations are used in FIG. 2: 50 Heat exchanger area coated with absorbent 51 Uncoated heat exchanger area 60 Flow of the fluid, advantageously air, to be dried or regenerated 61 Flow of the regeneration fluid, advantageously exhaust air, to be cooled

(5) FIG. 3: First routing state of the air conditioning apparatus of the invention

(6) In the lower part of FIG. 3, the optionally filtered exterior air flows into the apparatus and is conveyed via the left-hand branch into the sorption channels of the first heat exchanger which has been coated according to the invention. The dried air leaves the heat exchanger upward in the direction of a cooling element, here denoted by way of example by Peltier cooling. At top left of the figure, air flows from the interior space into the heat exchanger channels of the first, active heat exchanger and, heated by the heat of adsorption, leaves the latter at right in the direction of the supplementary heating device, here configured by way of example as electric tube heating. The heated air flows from above into the sorption channels of the second heat exchanger to be regenerated and leaves the apparatus with water vapor from the regeneration process.

(7) FIG. 4: Second routing state of the air conditioning apparatus of the invention. In the lower part of FIG. 4, the optionally filtered exterior air flows into the apparatus and is conveyed via the right-hand branch into the sorption channels of the previously regenerated heat exchanger which has been coated according to the invention. The dried air leaves the heat exchanger upward in the direction of a cooling element, here denoted by way of example by Peltier cooling. At top left in the figure, air flows from the interior space into the heat exchanger channels of the active heat exchanger and, heated by the heat of adsorption, leaves the latter at left in the direction of the supplementary heating device, here configured by way of example as electric tube heating. The heated air flows from above into the sorption channels of the second heat exchanger to be regenerated and leaves the apparatus with water vapor from the regeneration process.

EXAMPLE 1

(8) Aluminum fumarate was prepared as described in EP2 230 288.

(9) A dispersion composed of 1300 g of aluminum fumarate and 3300 g of distilled water was produced by stirring at 570 rpm by means of a toothed disk stirrer (7 cm disk diameter; Heidolph RZR2010control) for 15 minutes. After addition of 810 g of polyacrylate dispersion (Acronal® Edge, 40% solids content), the stirrer speed was increased to 740 rpm for 15 minutes. Five batches produced in this way were mixed using a propeller stirrer (diameter 10 cm, IKA EURO ST 40DS0000) and homogenized for 12 hours. The foam was subsequently removed and the dispersion was degassed by slow stirring.

(10) The dispersion had a viscosity of 4 Pa s at 10 Hz (measured using Anton Paar, MCR102, PP50, 400 μm gap, 25° C.).

(11) The dispersion was introduced twice through one of the two channel systems of a countercurrent heat exchanger made of aluminum (length 397 mm; height 172 mm; width 200 mm; channel width uncoated about 1 mm; Klingenburg GS18-200) and the channels were blown free by means of air. After drying of the heat exchanger, a total weight increase of 346 g, corresponding to an average layer thickness of 96 μm, was obtained.

Example 2

(12) A heat exchanger which had been coated as in example 1 was connected so that air at 27° C. with 90% relative atmospheric humidity (OL) was passed through the coated channel bundle (1) and air at 20° C. with 80% relative atmospheric humidity (IL) was passed through the other channel bundle. The flow rate was 50 m.sup.3/h. Within the first 5 minutes of operation of the adsorber, temperatures in the range from 28° C. to 32° C. and a relative atmospheric humidity in the range from 35% to 50% were established at the outflow end of the coated channel bundle (KL). The enthalpy of the air was for this purpose reduced isothermally from 80 kJ/kg to 63 kJ/kg.

(13) The outflow from the uncoated channel bundle (AL) displayed a temperature increase to 30° C. The enthalpy of this air stream rose from about 51 kJ/m.sup.3 to about 63 kJ/m.sup.3. The heat exchanger heated up by 10°. Within the first 5 minutes, 60 kJ/m.sup.3 were transferred from the exterior air stream (OL.fwdarw.KL) to the interior air stream (IL.fwdarw.AL), which corresponds to about 50% of the adsorption enthalpy of water on aluminum fumarate.

Example 3

(14) The heat exchanger of example 2 was flushed for 5 minutes with hot, dry air (90° C., 3% rel. atmospheric humidity). The experiment of example 2 was then repeated. Temperatures in the range from 27° C. to 33° C. and a relative atmospheric humidity in the range from 40 to 50% were measured at the outflow end of the coated channel bundle within the first 5 minutes.

Example 4

(15) Comparison with Kubota et al.

(16) TABLE-US-00001 According to the invention Kubota et al Heat exchanger Air-air plate heat Air-air plate heat exchanger, about 20 exchanger, about 20 cm × 20 cm × 40 cm, cm × 20 cm × 20 cm, without internal fins, with internal fins; internal surface area internal surface area about 1 m.sup.2 about 12 m.sup.2 Coating Aluminum fumarate, about Aluminophosphate, about 150 g/m.sup.2 30 g/m.sup.2 Total amount 150 g 360 g of absorbent Flow rate 60 m.sup.3/h 1 m/s, 72 m.sup.3/h Adsorption time 300 s 300 s to half maximum, measure of the cycle time

(17) Adsorption Time to Half Maximum:

(18) When exterior air (ODA) flows through a freshly regenerated heat exchanger, it is dried very quickly. The enthalpy of adsorption involved here produces a temperature increase. The increasing loading of the absorbent with water leads to a reduction in the uptake of moisture and the enthalpy of adsorption. The exiting air (SUP) therefore approaches the exterior air in respect of atmospheric humidity and temperature with increasing time. The operation then has to be switched over to the other cycle. The time from the commencement of the adsorption to the point in time when the temperature or atmospheric humidity has become equal to half the maximum of the exterior air conditions is selected as a characteristic measure of the cycle time of a setup having two alternately operated coated heat exchangers. Under these conditions, it can be assumed that the quickly available amount of adsorbent is loaded and the distribution of the enthalpy of adsorption is largely concluded.

(19) Explanation for Evaluation of the Measured Curves: FIG. 5

(20) Evaluation of the measured curve for 60 m.sup.3/h. The atmospheric humidity of the exterior air (ODA) is 20 g/kg, and that of the feed air (SUP) varies with the saturation of the adsorbent. In the case of a regenerated adsorbent, the atmospheric humidity is 5 g/kg, and after long times it approximates the exterior air. The curve can be characterized by means of the time to half maximum, here indicated by the lines at 13 g/kg and about 350 s.

(21) FIG. 6: Adsorption and desorption curve of aluminum-fumarate MOF. The graph shows the equilibrium state of the loading of MOF with water as a function of the relative atmospheric humidity. In contrast to typical analogous measurements on zeolites, the MOFs display a two-part curve: below 20% relative atmospheric humidity, the MOF does not take up any water vapor, i.e. it does not overdry the air. In the range from 20 to 40% relative atmospheric humidity, the MOF absorbs up to 30% of its own weight of moisture from the air. At even higher relative atmospheric humidities, a further continuous uptake of water occurs.

(22) Explanation for the Mollier Diagram, FIG. 7:

(23) The graph shows the possible combinations of absolute atmospheric humidity and temperature. In this depiction, the influence of the atmospheric humidity on the density of the air has been disregarded (this effect would allow the isotherms (states having the same temperature) to increase slightly from the left to the right.)

(24) The uptake capacity of air for water vapor increases with increasing temperature. The saturation curve is indicated as 100% relative atmospheric humidity. Below this temperature, atmospheric moisture condenses as mist. For this reason, it is also referred to as “mist curve”.

(25) The comfort range for office rooms is from 40% relative atmospheric humidity/20° C. to 60% relative atmospheric humidity/26° C.

(26) A typical example of exterior conditions in a hot humid climate is the point with 30° C. and 80% relative atmospheric humidity (about 23 g/kg of water vapor). To get into the range of interior room comfort, the air must, in particular, be dried. In the established air conditioning technology, this is achieved by cooling to about 10° C., so that the moisture in the air condenses out until the absolute atmospheric humidity is about 10-12 g/kg (mist curve).

(27) The air can be dried virtually isothermally by means of the coated heat exchanger of the invention, without being cooled.

(28) Drying without heat exchanger would lead to an increase in the temperature of the air as a result of liberation of the enthalpy of condensation and of adsorption of the water.