JP2023015876A - Adsorber for heat storage - Google Patents

Abstract

To provide a structure of an adsorbent suitable for adsorption for a relatively long time in an adsorber for heat storage that stores cold or heat by adsorption of an adsorbate to the adsorbent.SOLUTION: In an adsorber for heat storage that stores cold or heat by adsorption of an adsorbate to the adsorbent, on an outer periphery of a heat transfer pipe where a heating medium flows, an adsorption layer is formed by stacking the adsorbents at a plurality of stages to form a mesh shape. In the adsorber for heat storage, the adsorbents at the same stage are disposed in parallel in the same direction leaving gaps between them, and the adsorbents at the adjacent stages are disposed in the directions different from each other.SELECTED DRAWING: Figure 3

Description

The present invention relates to a heat storage adsorber.

Adsorbers are known in the art which contain adsorbents for adsorbing and desorbing vaporized adsorbates, such as water. For example, Patent Literature 1 listed below discloses a technique in which a working medium to be adsorbed by adsorbents is circulated through a channel disposed between a plurality of plate-shaped adsorbents. Further, Patent Document 2 below discloses a technique for circulating a working fluid through a plurality of holes formed in a plate-like adsorbent.

Japanese Patent No. 6045413 Japanese Patent No. 5900391

A conventional adsorber has an adsorption layer filled with an adsorbent and hardened on the outer periphery of a heat transfer tube through which a heat exchange medium flows. In this adsorption layer, the adsorbent is randomly packed. In such a conventional adsorber, the thickness of the adsorption layer is increased in order to increase the amount of adsorption by adsorbing the adsorbate over a relatively long period of time, such as one hour. will be However, in the case of an adsorption layer with such a packed structure, as the thickness of the adsorption layer increases, both the thermal resistance and the transport resistance of the adsorbate increase, resulting in a decrease in the utilization rate of the adsorbent. .

An object of the present disclosure is to realize an adsorbent structure suitable for adsorption for a relatively long time in a heat storage adsorber that stores cold or warm heat by adsorbing an adsorbate to the adsorbent.

A first embodiment of the present disclosure is a heat storage adsorber that stores cold or hot heat by adsorbing an adsorbate to an adsorbent, in which the adsorbent is formed in a mesh shape on the outer periphery of a heat transfer tube in which a heat medium flows. A plurality of stages are stacked, and the adsorbents in the same stage are arranged in parallel in the same direction, and the adsorbents in adjacent stages are arranged in different directions.

That is, since the adsorbents are stacked in multiple stages in a mesh shape, the adsorbents in the same stage are arranged in parallel in the same direction, and the adsorbents in adjacent stages are arranged in different directions, A flow path is provided between the adsorbents as a transfer route for the adsorbate. Since the flow path reduces the transfer resistance of the adsorbate, even if the thickness of the adsorption layer is increased, the thermal resistance does not increase.

In addition to the configuration of the first embodiment, the heat storage adsorber of the second embodiment of the present disclosure has a wire diameter of the adsorbent of w (mm) and a thickness of the adsorption layer of H (mm). when
0.95≦w≦1.47 and 13≦H≦(1100w−161)/52, or
1.47<w≦3.2 and 13≦H≦28,
is.

Here, in the above relational expression, between the wire diameter w of the adsorbent and the thickness H of the adsorption layer,
H = nw (where n is a natural number of 2 or more)
There is a relationship That is, an adsorption layer with a thickness H is formed by stacking n stages of adsorbents with a wire diameter w.

When the wire diameter w of the adsorbent and the thickness H of the adsorption layer satisfy the above relationship, the heat storage adsorber having such an adsorption layer adsorbs the adsorbate over a long period of time, for example, one hour. , the utilization rate of the adsorbent is improved and the power output in releasing cold or hot heat is increased.

The heat storage adsorber of the third embodiment of the present disclosure, in addition to the configuration of the second embodiment, has a wire diameter w (mm) of the adsorbent of 1.1 ≤ w ≤ 2.8
and
The thickness H (mm) of the adsorption layer is 16≦H≦21
is.

When the wire diameter w of the adsorbent and the thickness H of the adsorption layer satisfy the above relationship, the heat storage adsorber having such an adsorption layer adsorbs the adsorbate over a long period of time, for example, one hour. , the utilization rate of the adsorbent is further improved and the power output in discharging cold or hot heat is further increased.

A fourth embodiment of the present disclosure has the configuration of any one of the first to third embodiments, and in addition, the gap between the adjacent adsorbents is 500 μm or less.

By setting the gap between the adsorbents to 500 μm or less, it is possible to secure a path for the gaseous adsorbate to move within the adsorption layer, thereby improving the utilization rate of the adsorbent not only on the surface of the adsorption layer but also inside the adsorption layer. Although the lower limit of the gap between the adsorbent tubes is not particularly limited as long as it exceeds 0 μm, it is preferably 50 μm or more from the viewpoint of ensuring the movement of the adsorbate.

Since the embodiments of the present disclosure are configured as described above, in a heat storage adsorber that stores cold or warm heat by adsorbing an adsorbate to the adsorbent, an adsorbent that is suitable for adsorption for a relatively long time is used. A structure is realized.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram of the adsorption heat pump provided with the adsorption layer of embodiment. It is a schematic diagram which shows the structure of an adsorbent. It is a schematic diagram which shows the detailed structure of an adsorption layer. For an adsorption layer with a thickness H when the adsorbent is stacked in seven stages, (A) average cold power (VCP), (B) total heat storage density (Q), and (C) utilization rate (X) of the adsorbent It is the graph which measured the value. For an adsorption layer with a thickness H when the adsorbent is stacked in 10 layers, (A) average cold power (VCP), (B) total heat storage density (Q), and (C) utilization rate (X) of the adsorbent It is the graph which measured the value. For the adsorption layer of thickness H when the adsorbent is stacked in 13 stages, (A) average cold power (VCP), (B) total heat storage density (Q) and (C) utilization rate (X) of adsorbent It is the graph which measured the value. 4 is a graph showing measured values of (A) average cold power output (VCP), (B) total heat storage density (Q), and (C) adsorbent utilization (X) for the adsorption layer of the comparative example. FIG. 4 is a contour diagram showing calculation results of an average cold power output (VCP) with respect to a wire diameter w of an adsorbent and a thickness H of an adsorption layer. FIG. 4 is a contour diagram showing calculation results of a utilization rate (X) of the adsorbent with respect to the wire diameter w of the adsorbent and the thickness H of the adsorption layer.

(1) Schematic Configuration of Embodiment FIG. 1 is a schematic diagram of an adsorption heat pump 10 including an adsorption layer 20 of the embodiment. The adsorption heat pump 10 includes two heat storage adsorbers 6 and 7, two evaporative condensers 8 and 9, connection pipes 3a, 3b, 3c and 3d connecting these, connection pipes 3a, 3b and 3c, It includes a plurality of valves 4a, 4b, 4c, 4d arranged respectively in 3d, and a control unit (not shown). The adsorption heat pump 10 uses a combination of two sets of heat storage adsorbers 6 and 7 and evaporative condensers 8 and 9 to generate cold heat from hot heat.

The heat storage adsorbers 6 and 7 are respectively the reaction vessels 6a and 7a, the adsorbents 1 accommodated inside the reaction vessels 6a and 7a, and the heat exchangers for circulating the heat medium inside the reaction vessels 6a and 7a. 5 and . The adsorbent 1 adsorbs adsorbate vapors, for example water vapor, generated in the evaporative condensers 8,9. Also, the adsorbent 1 adsorbing water vapor desorbs the water vapor using the heat of a heat medium flowing through the heat exchanger 5, for example, hot water. In other words, the heat storage adsorbers 6 and 7 store cold heat or heat by adsorbing the adsorbate on the adsorbent 25 (see FIG. 3) that constitutes the adsorbent 1 .

The evaporative condensers 8 and 9 respectively have pipes 8a and 9a through which a heat medium flows, and storage vessels 8b and 9b that store adsorbate, such as water, to be adsorbed by the adsorbent 1 . In the evaporative condensers 8, 9, the heat medium flowing through the pipes 8a, 9a is cooled by the heat of vaporization when the adsorbate in the storage containers 8b, 9b evaporates according to the mode of the heat storage adsorbers 6, 7 connected. or the adsorbate vapor in the storage vessels 8b, 9b is condensed back to liquid.

Next, the action of the adsorption heat pump 10 of FIG. 1 will be described. In the state shown in FIG. 1, the valve 4a arranged in the connection pipe 3a connecting the heat storage adsorber 6 and the evaporative condenser 8, and the heat storage adsorber 7 and the evaporative condenser 9 are connected by a command from the control unit. is opened, the valve 4c arranged in the connection pipe 3c connecting the heat storage adsorber 6 and the evaporative condenser 9, and the heat storage adsorber 7 and the valve 4d arranged in the connecting pipe 3d connecting the evaporative condenser 8 is closed.

In the heat storage adsorber 6 and the evaporative condenser 8, which are connected via the connecting pipe 3a, the pressure inside is reduced by a pump (not shown) as an adsorption step. This produces adsorbate vapor in the evaporative condenser 8 . The generated adsorbate vapor passes through the connection pipe 3a (white arrow F11), enters the heat storage adsorber 6, and is adsorbed by the adsorbent 1. As shown in FIG. At this time, the heat medium such as water flowing through the pipe 8a of the evaporative condenser 8 is cooled by the heat of vaporization of the adsorbate. As a result, cold heat is supplied to the outside of the adsorption heat pump 10 by discharging a cooled heat medium such as cold water from the pipe 8a.

In the heat storage adsorber 7 and the evaporative condenser 9, which are connected via the connecting pipe 3b, a heat medium such as hot water is supplied to the heat exchanger 5 of the heat storage adsorber 7 as a desorption step. In the adsorbent 1 of the heat storage adsorber 7 that adsorbs the adsorbate, the adsorbate is desorbed from the adsorbate 1 by the heat of the heat medium supplied. The desorbed adsorbate enters the evaporative condenser 9 as vapor (white arrow F12) and is condensed by a heat medium such as water flowing through the pipe 9a to become a liquid such as water. This liquid heat carrier is utilized in the subsequent adsorption step.

In the adsorption heat pump 10 of FIG. 1, one of the heat storage adsorbers 6 and 7 adsorbs the vapor of the adsorbate, and the other desorbs the adsorbate. The production of cold by the feed of adsorbate is done continuously.

As shown in FIG. 2, the adsorbent 1 has a linear structure in which an adsorption layer 20 is formed on the outer circumference of a heat transfer tube 30 in which the flow path of the heat medium in the heat exchanger 5 is subdivided in the heat storage adsorbers 6 and 7. has a structure in which a large number of are bundled. In other words, an adsorption layer is formed by laminating the adsorbent in a plurality of mesh-like stages on the outer periphery of the heat transfer tube through which the heat medium flows. As shown in FIG. 3, the adsorption layer 20 has a mesh-like structure in which adsorbents 25 arranged in parallel in the same direction with gaps 25a interposed therebetween are laminated over a plurality of stages. Adjacent stages of adsorbent 25 are oriented in different directions as shown in FIG.

Let w (mm) be the wire diameter of the adsorbent 25 shown in FIG. 3, and let H (mm) be the thickness of the adsorption layer 20 in which the adsorbent 25 is stacked in multiple stages (four stages in FIG. 3, for example). 0.95≦w≦1.47 and 13≦H≦(1100w−161)/52, or 1.47<w≦3.2 and 13≦H≦28 It is desirable to have Specifically, although details will be described later, it is desirable to form the adsorbent 25 with a wire diameter w and a thickness H specified in the area inside the pentagon ABCDE in the graph of FIG. The cross-section of the adsorbent 25 may be substantially square as schematically shown in FIG. 3, or may be substantially circular. The wire diameter w in the case of a substantially square shape represents the length of one side, and the wire diameter w in the case of a substantially circular shape represents a diameter.

More preferably, 1.1≤w≤2.8 and 16≤H≤21. Specifically, although details will be described later, it is more preferable to form the adsorbent 25 with a wire diameter w and a thickness H specified in the area inside the rectangle A'B'C'D' in the graph of FIG. desirable.

The gap 25a between the adsorbents 25 is desirably 10 μm or more, more desirably 20 μm or more, most desirably 50 μm or more. Also, the gap 25a between the adsorbents 25 is desirably 1000 μm or less, more desirably 700 μm or less, most desirably 500 μm or less.

The material of the adsorbent 25 is not particularly limited as long as it can be used as an adsorbent in a normal heat exchanger, but it is desirable to use silica gel, 13X zeolite, or Y-type zeolite, for example. Moreover, it is desirable that the material of the adsorbent 25 contains a heat conduction aid such as carbon.

The wire diameter w of the suitable adsorbent and the thickness H of the adsorption layer were verified below. Specifically, the inner diameter of the heat transfer tube was set to 1 cm. In addition, the heat transfer tubes provided with the adsorption layers described below were arranged at intervals of 2 mm. As the material of the adsorbent 25, silica gel having a particle size of 74 μm is used as the main material, and carbon as a heat conduction aid is mixed with this at a rate of 10% by mass of the whole. Adsorbents obtained by forming this material into a linear shape having a substantially square cross section and a wire diameter w were laminated on the outer circumference of the heat transfer tube in n layers in a mesh shape as shown in FIG. 3 to form an adsorption layer. As an example, for a thermal storage adsorber comprising an adsorbent 1 with adsorbent layers formed with n=7 (FIG. 4), n=10 (FIG. 5) and n=13 (FIG. 6), the adsorption time The average cold power output (VCP), the total heat storage density (Q) and the utilization rate of the adsorbent (X) were measured when the time was set to 1 hour. The average cold output (kW/m ³ ) was calculated as power per unit volume. Total heat storage density (MJ/m ³ ) was calculated as energy per unit volume. The utilization rate of the adsorbent was calculated as the ratio of the amount of adsorbate actually adsorbed to the amount of adsorbate that could theoretically be adsorbed. Further, as a comparative example, the adsorption layer 20 in which the same material as the adsorbent 25 is attached to the outer periphery of the heat transfer tube 30 in a filling structure having a predetermined thickness H is also similarly average cold heat output (VCP), total heat storage density (Q ) and adsorbent utilization (X) were measured (FIG. 7).

In FIGS. 4 to 7, the relationship between the average cold heat output (VCP) and the thickness of the adsorption layer (H, unit: mm) is plotted on the vertical axis and the horizontal axis, respectively. (B) is a graph in which the relationship between the heat storage density (Q) and the thickness (H) of the adsorption layer is plotted on the vertical axis and the horizontal axis, respectively, and the utilization rate of the adsorbent (X) and the thickness of the adsorption layer. (C) is a graph in which the relationship with (H) is plotted on the vertical axis and the horizontal axis.

FIG. 4 shows the case where n=7, that is, the adsorption layer is formed by laminating seven layers of adsorbents. As shown in FIG. 4(A), the average cooling power (VCP) increased as the thickness H of the adsorption layer increased, showing a peak of over 40 kW/m ³ at about 16.8 mm. When the thickness H became more than that, the average cold heat output showed a gradual decreasing tendency. On the other hand, as shown in FIG. 4(B), the total heat storage density (Q) increased as the thickness H of the adsorption layer increased. Then the rate of increase seemed to approach a plateau. In addition, as shown in FIG. 4(C), the utilization rate (X) of the adsorbent rapidly exceeds 0.75 when the thickness H of the adsorption layer exceeds 0, but again FIG. It showed a decreasing tendency from the value of the thickness H showing a peak at . Therefore, when FIG. 4 (A) to (C) is put together, the combination of the thickness H of the adsorption layer of about 16.8 mm and the wire diameter w of the adsorbent divided by n in the vicinity of 2.4 mm is It has been found to be desirable as a heat storage adsorber.

FIG. 5 shows the case where n=10, that is, the adsorption layer is formed by stacking 10 layers of adsorbents. As shown in FIG. 5(A), the average cooling power (VCP) increased as the thickness H of the adsorption layer increased, and showed a peak exceeding 40 kW/m ³ at about 18 mm. When the thickness H became more than that, the average cold heat output showed a gradual decreasing tendency. On the other hand, as shown in FIG. 5(B), the total heat storage density (Q) increased as the thickness H of the adsorption layer increased. Then the rate of increase seemed to approach a plateau. In addition, as shown in FIG. 5(C), the utilization rate (X) of the adsorbent sharply exceeds 0.75 when the thickness H of the adsorption layer exceeds 0. However, as shown in FIG. It showed a decreasing tendency from the value of the thickness H showing a peak at . Therefore, when FIG. 5 (A) to (C) is summarized, the combination in which the thickness H of the adsorption layer is about 18 mm and the wire diameter w of the adsorbent divided by n is around 1.8 mm is suitable for heat storage. It was found to be desirable as an adsorber.

FIG. 6 shows the case where n=13, that is, the adsorption layer is formed by stacking 13 layers of adsorbents. As shown in FIG. 6(A), the average cooling power (VCP) increased as the thickness H of the adsorption layer increased, and showed a peak exceeding 40 kW/m ³ at about 19.5 mm. When the thickness H became more than that, the average cold heat output showed a gradual decreasing tendency. On the other hand, as shown in FIG. 6(B), the total heat storage density (Q) increased as the thickness H of the adsorption layer increased. Then the rate of increase seemed to approach a plateau. In addition, as shown in FIG. 6(C), the utilization rate (X) of the adsorbent sharply exceeds 0.75 when the thickness H of the adsorption layer exceeds 0. However, as shown in FIG. It showed a decreasing tendency from the value of the thickness H showing a peak at . 6A to 6C together, the combination of the thickness H of the adsorption layer of about 19.5 mm and the wire diameter w of the adsorbent divided by n in the vicinity of 1.5 mm is It has been found to be desirable as a heat storage adsorber.

In the comparative example shown in FIG. 7, probably because the adsorption layer does not have a laminated structure, the thickness H is about 3 mm as shown in FIG. The utilization factor (X) of the adsorbent reached a peak at 100.degree. C., and decreased sharply when the thickness H exceeded that. The same was true for the average cold heat output (VCP) (Fig. 7(A)). It should be noted that the total heat storage density (Q) shown in FIG. 7(B) increased as the thickness H of the adsorption layer increased, as in each example.

As described above, by having an adsorption layer in which the adsorbent is laminated in multiple stages, the adsorbent is more likely to come into contact with the adsorbate than in the case of a packed structure that does not have a laminated structure, so the utilization rate (X) of the adsorbent was improved, and the thickness H of the adsorption layer, which increased the average cold power output (VCP), was also increased. Regarding the total heat storage density (Q), it seems that it depends on the material of the adsorbent, so there was no big difference between each example and comparative example, but the utilization rate (X) and average cold power (VCP ) can be increased while the thickness H of the adsorption layer can be increased.

FIG. 8 is obtained by dividing each point plotted in FIGS. 4A, 5A and 6A by the thickness H of the adsorption layer on the x-axis and H on the y-axis divided by n. It is a contour diagram created based on a three-dimensional graph in which the average cold power output (VCP) is three-dimensionally plotted on the wire diameter w of the adsorbent and the z axis. The numerical values shown in FIG. 8 represent the numerical range of the average cold power output (VCP) of the region. 9, each point plotted in FIG. 4(C), FIG. 5(C) and FIG. 6(C) is plotted with the thickness H of the adsorption layer on the x-axis and H divided by n on the y-axis. 2 is a contour diagram created based on a three-dimensional graph obtained by three-dimensionally plotting the wire diameter w of the adsorbent and the utilization rate (X) of the adsorbent on the z-axis. The numerical values shown in FIG. 9 represent the numerical range of the utilization rate (X) of the adsorbent in the region. In the graphs of FIGS. 8 and 9, the non-shaded area in the upper left indicates an area where the numerical value cannot be complemented because the value of n, which is the number of layers of the adsorbent layered, becomes too large. .

In FIG. 8, point A with w=1.47 and H=28, point B with w=3.2 and H=28, point C with w=3.2 and H=13, w=0. An adsorbent with wire diameter w and thickness H within the pentagon ABCDE bounded by point D where 95 and H = 13 and point E where w = 0.95 and H = 17 is at least 40 kW/m It can be seen that an average cold power output (VCP) of ³ is obtained.

Here, a straight line AE passing through the points A and E can be seen as a function of the wire diameter w and the thickness H. If this function is
H=aw+b Expression (1)
and Here, a in the above formula (1) represents the slope of this straight line, and b represents the y-intercept of this straight line.

By solving the simultaneous equations obtained by substituting w = 1.47 and H = 28 at point A and w = 0.95 and H = 17 at point E into this equation 1, a in the above equation (1) and b are determined. As a result, the straight line AE is
H=(1100w-161)/52 Expression (2)
It can be expressed as. therefore,
H≤(1100w-161)/52
is the area below the straight line AE in FIG.

That is, the relationship between the wire diameter w of the adsorbent within the range within the pentagon ABCDE in FIG. 8 and the thickness H of the adsorption layer is
0.95≦w≦1.47 and 13≦H≦(1100w−161)/52, or
1.47<w≦3.2 and 13≦H≦28,
is represented.

That is, when the wire diameter w of the adsorbent and the thickness H of the adsorption layer satisfy the above relationship ^, the heat storage adsorber using this adsorbent has a high average cold power output (VCP ) will be obtained. When this range is applied to FIG. 9, when the wire diameter w of the adsorbent and the thickness H of the adsorption layer satisfy the above relationship, the utilization rate (X) of the adsorbent is approximately 0.75 or more, which is also high. value will be obtained.

In FIG. 8, point A' where w=1.1 and H=21, point B' where w=2.8 and H=21, and point C' where w=2.8 and H=16. , w=1.1 and H=16, the adsorbent having a wire diameter w and a thickness H within the rectangle A'B'C'D' enclosed by the point D' where w=1.1 and H=16. ³ , and even higher average cold power output (VCP) can be obtained. Incidentally, from FIG. 9, the utilization rate (X) of the adsorbent within the range of this rectangle A'B'C'D' exceeds 0.75.

That is, the wire diameter w (mm) of the adsorbent is 1.1 ≤ w ≤ 2.8
and the thickness H (mm) of the adsorption layer is 16 ≤ H ≤ 21
As a result, a heat storage adsorber using this adsorbent can stably obtain a higher average cold power output (VCP).

1 Adsorbents 3 a, 3 b, 3 c, 3 d Connection pipes 4 a, 4 b, 4 c, 4 d Valve 5 Heat exchanger 6 Heat storage adsorber 6 a Reaction vessel 7 Heat storage adsorber 7 a Reaction vessel 8 Evaporative condenser 8 a Piping 8 b Storage vessel 9 Evaporative condenser 9a Piping 9b Storage container 10 Adsorption heat pump 20 Adsorption layer 25 Adsorbent 25a Gap 30 Heat transfer tube

Claims (4)

In a heat storage adsorber that stores cold or warm heat by adsorbing an adsorbate to an adsorbent,
An adsorption layer is formed by stacking a plurality of stages of the adsorbents in a mesh shape on the outer circumference of the heat transfer tube through which the heat medium flows, and the adsorbents in the same stage are arranged in parallel with each other in the same direction with a gap therebetween. , wherein the adsorbents in adjacent stages are oriented in different directions from each other. When the wire diameter of the adsorbent is w (mm) and the thickness of the adsorption layer is H (mm),
0.95≦w≦1.47 and 13≦H≦(1100w−161)/52, or
1.47<w≦3.2 and 13≦H≦28,
The heat storage adsorber according to claim 1, wherein The wire diameter w (mm) of the adsorbent is 1.1 ≤ w ≤ 2.8
and
The thickness H (mm) of the adsorption layer is 16≦H≦21
The heat storage adsorber according to claim 2, wherein 4. The heat storage adsorber according to any one of claims 1 to 3, wherein said gap is 500 [mu]m or less.

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