Dual rotor air handling unit comprising purge air circuit

Abstract

The present disclosure relates to a dual rotor air handling unit for carbon dioxide removal, wherein energy efficiency and air quality is simultaneously obtained by at least one purge air circuitry connecting a process air circuitry to a regeneration air circuitry.

Description

[0001] AIR HANDLING UNIT

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to energy efficient dual rotor air handling units.

[0004] BACKGROUND ART

[0005] Air handling units for air purification, such as air handling units for removal of carbon dioxide from the air, have many passive and powered components that operate in tandem to process the air. The complex interplay of the passive and powered components of the air handling unit may lead to inefficient power usage. There is thus a need in the art for air handling units with improved energy efficiency.

[0006] SUMMARY OF THE INVENTION

[0007] The present disclosure relates to an air handling unit, AHU. The AHU comprises a first rotor comprising a desiccant material, and a second rotor comprising a carbon dioxide capture material. The AHU further comprises a process air circuit configured to conduct process air through a first process sector of the first rotor and a second process section of the second rotor, and a regeneration air circuit configured to conduct regeneration air through a first regeneration section of the first rotor and a second regeneration sector of the second rotor. The AHU also comprises a first heater configured to heat the regeneration air downstream of the second rotor and upstream of the first rotor, and a second heater configured to heat the regeneration air upstream of the second rotor. The AHU additionally comprises at least one purge air circuit configured to conduct purge air through respective purge sectors of the second rotor. The at least one purge air circuit is connected to the regeneration air circuit downstream of the second rotor and / or upstream of the second heater. The at least one purge air circuit is configured to collect the purge air from the process air upstream and / or downstream of the second rotor.

[0008] The second rotor is arranged downstream of the first rotor in the process air circuit and the first rotor is arranged downstream of the second rotor in the regeneration air circuit. The at least one purge air circuit will recycle remaining heat from the regeneration sector and exit the second rotor warmer than it entered. This air stream may still contain carbon dioxide but will have a very low water content. If mixed into the regeneration air of the regeneration air circuit downstream of the second rotor, it can improve the regeneration by reducing the humidity, since energy usage of the first heater is decreased at the same time by preheating the air with the purge. Similarly, if mixed into the regeneration air of the regeneration air circuit upstream of the second heater, energy usage of the second heater is decreased.

[0009] Process air, regeneration air and purge air are considered known within the technical field of air handling units and the purpose of such airflows will not be described in more detail herein.

[0010] According to some examples, the at least one purge air circuit comprises a first purge air circuit configured to collect the purge air from the process air upstream of the second rotor and connect to the regeneration air circuit upstream of the second heater.

[0011] According to some examples, the at least one purge air circuit comprises a second purge air circuit configured to collect the purge air from the process air upstream of the second rotor and connect to the regeneration air circuit downstream of the second rotor.

[0012] According to some examples, the at least one purge air circuit comprises a third purge air circuit configured to collect the purge air from the process air downstream of the second rotor and connect to the regeneration air circuit downstream of the second rotor.

[0013] By collecting purge air downstream of the second rotor, the purge air will enter the second rotor from the hotter side and pick up more of the heat from the second rotor, thereby simultaneously improving the temperature of the second rotor and the amount of heat transported to the regeneration air circuit.

[0014] According to some examples, the at least one purge air circuit comprises a fourth purge air circuit configured to collect the purge air from the process air downstream of the second rotor and connect to the regeneration air circuit upstream of the second heater.

[0015] By collecting purge air downstream of the second rotor, the purge air will enter the second rotor from the hotter side and pick up more of the heat from the second rotor, thereby simultaneously improving the temperature of the second rotor and the amount of heat transported to the regeneration air circuit. According to some examples, the AHU further comprises a fifth purge air circuit configured to conduct purge air through a first purge sector in a first direction through the second rotor, and through a second purge sector in a second direction through the second rotor, wherein the first direction is opposite to the second direction.

[0016] According to some examples, the AHU further comprises a sixth purge air circuit configured to conduct purge air through a purge sector of the first rotor, wherein the sixth purge air circuit is connected to the regeneration air circuit upstream of the first heater, and wherein the sixth purge air circuit is configured to collect the purge air from the process air upstream of the first rotor.

[0017] According to some examples, the AHU further comprises a seventh purge air circuit configured to conduct purge air through a first purge sector in a first direction through the first rotor, and through a second purge sector in a second direction through the first rotor, wherein the first direction is opposite to the second direction.

[0018] The term upstream, when used in relation to a first component at an air circuit, means upstream of the first component and downstream of any component upstream of the first component. For instance, upstream of the first heater (which is arranged at the regeneration air circuit) also implies downstream of the second rotor.

[0019] Likewise, the term downstream, when used in relation to a second component at an air circuit, means downstream of the second component and upstream of any component downstream of the second component. For instance, downstream of the first rotor along the process air circuit means downstream of the first rotor and upstream of the second rotor. Similarly, downstream of the second rotor along the regeneration air circuit means downstream of the second rotor and upstream of the first heater.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1a schematically illustrates an air handling unit according to examples of the present disclosure; and

[0022] Figures 1 b-1 r schematically illustrate purge air circuits according to examples of the present disclosure. DETAILED DESCRIPTION

[0023] Figure 1a schematically illustrates an air handling unit, AHU, 100a-r according to the present disclosure and Figures 1 b-1 r schematically illustrate different example configurations of purge air circuits of the AHU as disclosed in Figure 1 a.

[0024] The AHU comprises a first rotor 110 comprising a desiccant material, and a second rotor 120 comprising a carbon dioxide capture material.

[0025] The AHU further comprises a process air circuit S1 configured to conduct process air through a first process sector z1 a of the first rotor 110 and a second process section z1 b of the second rotor 120.

[0026] The AHU also comprises a regeneration air circuit S2 configured to conduct regeneration air through a first regeneration section z2a of the first rotor 110 and a second regeneration sector z2b of the second rotor 120.

[0027] The AHU additionally comprises a first heater 130a configured to heat the regeneration air downstream of the second rotor 120 and upstream of the first rotor 110, and a second heater 130b configured to heat the regeneration air upstream of the second rotor 120.

[0028] The AHU further comprises at least one purge air circuit configured to conduct purge air through respective purge sectors z3a-d of the second rotor 120. The at least one purge air circuit S3a-d is connected to the regeneration air circuit S2 downstream of the second rotor 120 and / or upstream of the second heater 130b, and wherein the at least one purge air circuit S3a-d is configured to collect the purge air from the process air upstream and / or downstream of the second rotor 120.

[0029] Each rotor 110, 120 is configured to rotate about a central axis. Each rotor is configured to rotate in respective first and second rotational directions r1 , r2. For illustrative purposes, the first and second rotational directions r1 , r2 are depicted as rotating in the same direction, clockwise when viewed in the same direction as the flow of the process air of the process air circuit S1 . It should be noted however that the rotational directions can be going in the opposite direction of what is illustrated in the Figures herein. Moreover, the rotational directions may be configured to rotate in opposite directions. As the rotors rotate, different portions of the respective rotors will overlap with any purge sector and / or the process and regeneration sectors described herein, with the sector overlap order being determined by the rotational directions. The rotational directions r1 , r2 will therefore have an impact on the technical effects of purge circuits as described below, in particular with the relative placement of a purge sector with respect to any other purge sector and / or the process and regeneration sectors described herein. The relative placement of purge sectors of one or more purge air circuits are thus arranged in relation to the rotational direction of the respective rotor, which will be illustrated further below.

[0030] It should be noted that the purge sectors of Fig. 1 a are illustrated only to assist in viewing the respective connections of the purge sectors and their optimal relative placement relative to each other and the rotational directions r1 , r2 will be illustrated in relation to Figures 1 b-1 r below.

[0031] Figures 1 b-1 e illustrate purge air circuit options for the first rotor 110. Figure 1 b illustrates an example of no purge air circuit.

[0032] Figure 1c illustrates an example wherein the AHU 100a-r further comprising a sixth purge air circuit S5 configured to conduct purge air through a purge sector z5 of the first rotor 110, wherein the sixth purge air circuit S5 is connected to the regeneration air circuit S2 upstream of the first heater 130a, and wherein the sixth purge air circuit S5 is configured to collect the purge air from the process air upstream of the first rotor 110. The additional heat recovery added to the first rotor increases the energy efficiency AHU further.

[0033] Figure 1 d illustrates an example wherein the AHU 100a-r further comprising a seventh purge air circuit S6 configured to conduct purge air through a first purge sector z6a in a first direction through the first rotor 110, and through a second purge sector z6b in a second direction through the first rotor 110, wherein the first direction is opposite to the second direction. Energy efficiency is thereby further improved by adding the additional heat recovery at the first rotor.

[0034] Figure 1 e illustrates an example wherein the AHU comprises both a sixth purge air circuit S5 and a seventh purge air circuit S6. In a preferred example, the purge sectors are arranged relative to each other as shown in Fig. 1 e, assuming a rotational direction r1 as illustrated in Figs. 1 a-1 b. In other words, when viewed with respect to the rotational direction r1 of the first rotor 110, the second purge sectors z6b of the seventh purge air circuit S6 follows the first regeneration section z2a of the first rotor, and followed by the purge sector z5 of the sixth purge air circuit S5.

[0035] Figures 1f-1 r illustrate examples of purge air circuits of the second rotor 120. For illustrative purposes, the rotational direction r2 is assumed to be as illustrated in Fig. 1 a and Fig. 1f.

[0036] Figure 1f illustrates an example wherein the at least one purge air circuit S3a-d comprises a first purge air circuit S3a configured to collect the purge air from the process air upstream of the second rotor 120 and connect to the regeneration air circuit S2 upstream of the second heater 130b.

[0037] This will recycle remaining heat from the regeneration sector and exit the rotor warmer than it entered. This air stream may still contain carbon dioxide but will have a very low water content. If mixed into the regeneration air stream upstream of the second rotor, it can improve the regeneration by reducing the humidity. Energy usage of the second heater is decreased at the same time by preheating the air with the purge.

[0038] Figure 1 g illustrates an example wherein the at least one purge air circuit S3a-d comprises a second purge air circuit S3b configured to collect the purge air from the process air upstream of the second rotor 120 and connect to the regeneration air circuit S2 downstream of the second rotor 120.

[0039] This will recycle remaining heat from the regeneration sector and exit the rotor warmer than it entered. This air stream may still contain carbon dioxide but will have a very low water content. If mixed into the regeneration air stream upstream of the first rotor, it can improve the regeneration by reducing the humidity. Energy usage of the first heater is decreased at the same time by preheating the air with the purge.

[0040] The side of the second rotor 120 closest to the second heater 130b will typically be hotter than the opposite side. It can therefore be advantageous to configure purge air circuits to enter from the hotter side, as illustrated in Figs. 1 h and 1 i below.

[0041] Figure 1 h illustrates an example wherein the at least one purge air circuit S3a-d comprises a third purge air circuit S3c configured to collect the purge air from the process air downstream of the second rotor 120 and connect to the regeneration air circuit S2 downstream of the second rotor 120. Figure 1 i illustrates an example wherein the at least one purge air circuit S3a-d comprises a fourth purge air circuit S3d configured to collect the purge air from the process air downstream of the second rotor 120 and connect to the regeneration air circuit S2 upstream of the second heater 120.

[0042] Figure 1j illustrates an example wherein the AHU 100a-r further comprises a fifth purge air circuit S4 configured to conduct purge air through a first purge sector z4a in a first direction through the second rotor 120, and through a second purge sector z4b in a second direction through the second rotor 120, wherein the first direction is opposite to the second direction.

[0043] Figures 1 k-1 r illustrate examples of how different purge air circuits can be combined.

[0044] In the example of Fig. 1 o, an extremely low carbon dioxide level can be obtained in the resulting process air, in particular when combined with any of the purge air circuitry of Figs. 1 c-e. In the illustrated example and with the rotational direction of Fig. 1a or Fig. 1f, carbon dioxide is first removed by the regeneration air circuity. The portion of the second rotor from which carbon dioxide has been removed is then gradually rotated to overlap with the purge sector of the second purge air circuit S3b, where additional carbon dioxide is removed by a dehydrated air stream. Finally, the portion of the second rotor from which carbon dioxide has been removed is rotated to overlap with the purge sector of the first purge air circuit S3a, which will remove most of the remaining carbon dioxide.

[0045] Additional energy efficiency can be obtained by also including a fifth purge air circuit S4, as illustrated in Fig. 1 p.

[0046] Figures 1 q and 1 r illustrate examples corresponding to those of Figures 1o and 1 p, wherein the purge air is collected downstream of the second rotor 120. The examples illustrated in Figures 1 q and 1 r allow spreading heat from purge air over two points of the regeneration air circuit S2, compared to the examples of Fig. 1 h and 1 i, thereby improving flexibility in how the heat should be distributed. The respective purge sectors z3c and z3d of Figures 1q and 1 r can optionally be made smaller than corresponding purge sectors of Figures 1 h and 1 i.

Claims

8CLAIMS1 . An air handling unit, AHU, (1 OOa-r) the AHU comprising• a first rotor (110) comprising a desiccant material, and• a second rotor (120) comprising a carbon dioxide capture material,• a process air circuit (S1 ) configured to conduct process air through a first process sector (z1 a) of the first rotor (110) and a second process section (z1 b) of the second rotor (120),• a regeneration air circuit (S2) configured to conduct regeneration air through a first regeneration section (z2a) of the first rotor (110) and a second regeneration sector (z2b) of the second rotor (120),• a first heater (130a) configured to heat the regeneration air downstream of the second rotor (120) and upstream of the first rotor (110),• a second heater (130b) configured to heat the regeneration air upstream of the second rotor (120),• at least one purge air circuit (S3a-d) configured to conduct purge air through respective purge sectors (z3a-d) of the second rotor (120), wherein the at least one purge air circuit (S3a-d) is connected to the regeneration air circuit (S2) downstream of the second rotor (120) and / or upstream of the second heater (130b), wherein the at least one purge air circuit (S3a-d) is configured to collect the purge air from the process air upstream and / or downstream of the second rotor (120), and wherein the at least one purge air circuit (S3a-d) comprises a second purge air circuit (S3b) configured to collect the purge air from the process air upstream of the second rotor (120) and connect to the regeneration air circuit (S2) downstream of the second rotor (120).

92. The AHU (1 OOa-r) according to claim 1 , wherein the at least one purge air circuit (S3a-d) comprises a first purge air circuit (S3a) configured to collect the purge air from the process air upstream of the second rotor (120) and connect to the regeneration air circuit (S2) upstream of the second heater (130b).

3. The AHU (1 OOa-r) according to any of the preceding claims, wherein the at least one purge air circuit (S3a-d) comprises a third purge air circuit (S3c) configured to collect the purge air from the process air downstream of the second rotor (120) and connect to the regeneration air circuit (S2) downstream of the second rotor (120).

4. The AHU (1 OOa-r) according to any of the preceding claims, wherein the at least one purge air circuit (S3a-d) comprises a fourth purge air circuit (S3d) configured to collect the purge air from the process air downstream of the second rotor (120) and connect to the regeneration air circuit (S2) upstream of the second heater (120).

5. The AHU (1 OOa-r) according to any of the preceding claims, further comprising a fifth purge air circuit (S4) configured to conduct purge air through a first purge sector (z4a) in a first direction through the second rotor (120), and through a second purge sector (z4b) in a second direction through the second rotor (120), wherein the first direction is opposite to the second direction.

6. The AHU (1 OOa-r) according to any of the preceding claims, further comprising a sixth purge air circuit (S5) configured to conduct purge air through a purge sector (z5) of the first rotor (110), wherein the sixth purge air circuit (S5) is connected to the regeneration air circuit (S2) upstream of the first heater (130a), and wherein the sixth purge air circuit (S5) is configured to collect the purge air from the process air upstream of the first rotor (110).

7. The AHU (1 OOa-r) according to any of the preceding claims, further comprising a seventh purge air circuit (S6) configured to conduct purge air through a first purge sector (z6a) in a first direction through the first rotor (110), and through a second purge sector (z6b) in a second direction through the first rotor (110), wherein the first direction is opposite to the second direction.

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