HEAT EXCHANGER FOR TEMPERATURE CONTROL OF A SUBSTRATE FOR CULTIVATING HORTICULTURAL PRODUCTS, SUBSTRATE DRAWER, AND RACK

Abstract

A heat exchanger for temperature control of a substrate for cultivating horticultural products. The heat exchanger has a structure comprising a heat exchange surface arranged for heating or cooling the substrate. The structure is arranged for supporting the substrate for thereby forming a carrier plate with a carrier surface such that the heat exchange surface forms the carrier surface. The heat exchanger comprises or is configured for cooperating with one or more mounts arranged for suspending the heat exchanger to a rack. The structure of the heat exchanger is constructed such as to be self-supporting for supporting the substrate at least between the one or more mounts, such that a bottom surface of the structure opposite the heat exchange surface faces an ambient environment.

Claims

1. A rack for carrying a substrate for cultivating horticultural products, wherein the rack is provided with a heat exchanger for temperature control of the substrate, the heat exchanger having a structure comprising a heat exchange surface arranged for heating or cooling the substrate, wherein the structure is arranged for supporting the substrate for thereby forming a carrier plate with a carrier surface such that the heat exchange surface forms the carrier surface, wherein mounts suspend the heat exchanger at or along its edges to the rack, and wherein the structure of the heat exchanger is constructed such as to be self-supporting for supporting the substrate at least between the one or more mounts without additional support elements below the heat exchanger, such that a bottom surface of the structure opposite the heat exchange surface faces an ambient environment, wherein the structure comprises an extendible section, configured to extend or shorten laterally in plane of the carrier plate between the mounts for compensating thermally induced contraction or expansion of the heat exchanger, respectively.

2. The rack according to claim 1, wherein the structure of the heat exchanger comprises one or more support members, wherein the one or more support members provide structural integrity in a direction parallel to the plane of the carrier plate.

3. The rack according to claim 1, wherein the structure forms an impervious barrier, arranged for preventing passage of substrate material through the structure.

4. The rack according to claim 1, wherein the extendible section is configured to extend or shorten by elastic deformation thereof.

5. The rack according to claim 4, wherein the structure comprises at least two compartments, wherein the extendible section is formed by at least one compartment of the at least two compartments.

6. The rack according to claim 5, wherein each compartment of the at least two compartments comprises a circumferential outer wall, providing the heat exchange surface.

7. The rack according to claim 6, wherein the circumferential outer wall comprises a top portion and a bottom portion, wherein the top portion and the bottom portion are interconnected at respective opposing end sections thereof in plane of the carrier plate, and wherein each of the top and bottom portion comprises a middle section that is bent outwards with respect to the plane of the carrier plate.

8. The rack according to claim 7, wherein the circumferential outer wall has a diamond shaped cross section, having a long diagonal and a short diagonal, wherein the long diagonal is in plane of the carrier plate and wherein the short diagonal is perpendicular to the plane of the carrier plate.

9. The rack according to claim 8, wherein the at least two compartments are interconnected by elastic elements, that are elastically deformable in plane of the carrier plate.

10. The rack according to claim 5, wherein each compartment of the at least two compartments comprises a channel, through which a fluid can flow for heating or cooling the heat exchange surface.

11. The rack according to claim 10, wherein the channel is connectable to an energy recovery system, the energy recovery system being arranged for recovering energy from heat produced by the substrate.

12. The rack according to claim 1, wherein the structure comprises one or more walls mounted to the carrier plate.

13. The rack according to claim 1, wherein the one or more mounts, for movably mounting the heat exchanger to the rack, comprise at least one of: bearings, rails or a carriage or sled.

14. The rack according to claim 1, wherein a bottom side of the heat exchanger is provided with a light source.

15. The rack according to claim 8, wherein the heat exchanger is circumferentially provided with one or more elastically deformable elements; wherein the at least two compartments are rigidly interconnected.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The invention will be further elucidated in the figures:

[0030] FIG. 1 illustrates a cross sectional view of an embodiment of a heat exchanger;

[0031] FIG. 2 illustrates a cross sectional view of another or further embodiment of a heat exchanger, comprising a support member;

[0032] FIG. 3 illustrates a top view of another or further embodiment of a heat exchanger;

[0033] FIG. 4, illustrates a cross sectional view of another or further embodiment of a heat exchanger, comprising compartments;

[0034] FIG. 5 illustrates a substrate drawer, provided with a heat exchanger as described herein;

[0035] FIG. 6 illustrates a rack, provided with a heat exchanger as described herein;

[0036] FIG. 7 illustrates a rack, provided with a substrate drawer as described herein.

DETAILED DESCRIPTION

[0037] The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. In the drawings, the absolute and relative sizes of systems, components, layers, and regions may be exaggerated for clarity. Embodiments may be described with reference to schematic and/or cross-section illustrations of possibly idealized embodiments and intermediate structures of the invention. In the description and drawings, like numbers refer to like elements throughout. Relative terms as well as derivatives thereof should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the system be constructed or operated in a particular orientation unless stated otherwise.

[0038] FIG. 1 illustrates an embodiment of a heat exchanger 100 for temperature control of a substrate 200 for cultivating horticultural products 50, e.g. as part of a horticultural growing arrangement. The substrate 200 can for example be a layer of soil, sawdust or straw, or any other substrate material suitable for growing horticultural products 50, such as mushrooms, fruits, vegetables, herbs or mycelium. For example, the horticultural products 50 illustrated in FIGS. 1, 3 represent mushrooms, the horticultural products 50 illustrated in FIGS. 2 and 6 represent fruits, vegetables or herbs, and the horticultural products 50 illustrated in FIGS. 5 and 7 represent mycelium. The example types of horticultural products 50 illustrated in these figures are not bound or limited to the corresponding embodiments of the heat exchanger shown in the respective figures. Other combinations of embodiment of the heat exchanger 100 and type of horticultural product 50 may be possible.

[0039] As shown in FIG. 1, the heat exchanger 100 has a structure 110 that comprises a heat exchange surface 111, e.g. on the side of the heat exchanger facing the substrate 200, arranged for heating or cooling the substrate 200. For example, when growing mycelium, heat may be produced by the mycelium in the substrate 200, and the temperature of the substrate 200 can be controlled by having the heat exchanger 100 cool the substrate 200. In other instances, for example when the mycelium is ready for harvesting, the mycelium can be dried by having the heat exchanger 100 heat the substrate 200.

[0040] The structure 110 of the heat exchanger 100 is arranged for supporting the substrate 200, for thereby forming a carrier structure, e.g. a carrier plate with a carrier surface. Accordingly, contrary to conventional arrangements for cultivating horticultural products, there is no need for a separate carrier structure, and the total thermal mass of the arrangement, which may act as a heat sink or heat source, can be reduced. As a result, controllability of the temperature of the substrate 200 can be improved, and the energy efficiency of the heat exchanger 100 can be increased.

[0041] As illustrated in FIG. 1, the heat exchange surface 110 forms the carrier surface for carrying the substrate 200. As such, when transferring heat between the heat exchanger 100 and the substrate 200, loss of energy is minimized, e.g. by minimizing the thermal mass between the heat exchanger 100 and the substrate 200. To further minimize thermal masses, the heat exchanger 100 comprises or is configured for cooperating with one or more mounts 120 arranged for suspending the heat exchanger 100 to a support structure, and the structure 110 of the heat exchanger 100 is constructed such as to be self-supporting for supporting the substrate 200 at least between the one or more mounts 120, e.g. in a rack.

[0042] For example, each mount 120 may have a contact area through which heat can be transferred, e.g. by conduction, between the heat exchanger 100 and the support structure when the heat exchanger 100 is suspended to the support structure. To limit transfer of heat between the heat exchanger and the support structure, the contact area may be relatively small. Alternatively, the number of mounts 120 may be reduced. For example, the total contact area of the one or more mounts 120 combined may be significantly smaller than the carrier surface area, e.g. less than 10% of the carrier surface area, preferably less than 5% of the carrier surface area.

[0043] The one or more mounts 120 can for example be arranged along one or more edges of the heat exchanger 100, e.g. between opposing edges of the heat exchanger 100. The mounts 120 can be arranged for rigidly or movably suspending the heat exchanger 100, e.g. by comprising a clamping arrangement or a bearing arrangement, respectively, or by any combination of rigid and movable suspension arrangements.

[0044] When the heat exchanger 100 is suspended as carrier plate between the mounts 120 for supporting the substrate 200, the structure 110 of the heat exchanger 100 is self-supporting. In this way, the bottom surface 112 of the structure 110 opposite the heat exchange surface 111 can face an ambient environment. In other words, the bottom surface 112 can be freely accessible from and/or be in direct contact with the ambient environment, because it is not substantially covered by supporting elements, such as plates or frames, by insulating material, or by grates. As such, e.g. when the heat exchanger 100 is suspended in a rack, the bottom surface 112 can for example be arranged for heating or cooling a substrate located on a level below the heat exchanger 100.

[0045] Preferably, the structure 110 forms an impervious barrier, arranged for preventing passage of substrate material, such as sand or dirt, through the structure 110, so that any horticultural products 50 cultivated on a level below the heat exchanger 100 are not contaminated by the substrate material.

[0046] During normal operating conditions, a gravitational load is exerted on the heat exchanger 100, e.g. comprising the own weight of the heat exchanger 100, the weight of substrate 200 and the weight of any horticultural products 50 cultivated thereon. The structure 110 may be self-supporting so that, e.g. under the gravitational load, the deformation of the heat exchanger 100, due to bending stress, is within an elastic deformation regime, while the deflection of the carrier surface is within a deflection threshold.

[0047] The structure 110 can for example be made of an aluminium alloy material, or any other material that has a relatively high thermal conductivity, Young's module and yield strength, versus a relatively low density, such as steel alloys, magnesium alloys, or brass alloys.

[0048] Alternatively, or additionally, the structure 110 can be designed to have a relatively high bending stiffness in a direction normal to the plane of the carrier surface, to minimalize deflection of the carrier surface due to gravitational loads. For example, the second moment of area of the structure 110, around an axis in plane P of the carrier plate, can be increased by maximizing the height of the structure 110 in a direction normal to the plane P of the carrier plate. As such, the out of plane bending resistance of the structure 110 can be increased. By maximizing the height H, the structure 110 can remain thin walled. In this way, the thermal resistance of the heat exchanger 100, for transferring heat between the heat exchanger 100 and the substrate 200, can be minimalized.

[0049] A further synergistic effect of maximizing the height H while minimizing the wall thickness of the structure 110 is that the mass of the heat exchanger 100, and thus the gravitational load as well as the thermal mass, can be reduced. Accordingly, the structure 110 of the heat exchanger 100 can provide improved mechanical properties, for supporting the substrate 200, as well as improved thermal properties, for exchanging heat with the substrate 200.

[0050] FIG. 2 illustrates a cross sectional view of an embodiment of a heat exchanger 100, wherein the structure 110 comprises one or more support members 118 that provide structural integrity in a lateral direction, parallel to the plane P of the carrier plate. The support members 118, such as beams, bars, brackets, or plates, can be arranged at an offset to the plane P to support the bottom surface 112, e.g. directly or via intermediate bushings. The one or more support members 118 may span between longitudinal edges of the carrier plate, between lateral edges of the carrier plate, and/or between corners of the carrier plate. Since the bottom surface 112 of the structure 110 opposite the heat exchange surface 111 is intended to face an ambient environment, the one or more support members 140 may be relatively slender, to minimally obstruct the bottom surface 111, as shown in FIG. 3. For example, the support member 118 can comprise a folded plate, e.g. with a U profile having legs oriented perpendicular to the plane P of the carrier plate. The support member 118 can be provided with alignment means, such as cutouts or protrusions, for aligning the carrier plate with the support member.

[0051] As illustrated in FIG. 2, the structure 110 can further comprise an extendible section 115. The extendible section is configured to extend or shorten in plane P of the carrier plate for compensating thermally induced contraction or expansion of the heat exchanger 100, respectively. For example, when the heat exchanger 100 heats up the substrate 200, the structure 110 may expand in plane P of the carrier plate. Since the expansion of the structure 110 may be laterally constrained, e.g. due to the fixation of the heat exchanger 100 to a rack or other support structure, thermally induced stress may build up inside the structure, which can cause irreversible damage to the heat exchanger 100. In such cases, the extendible section 115 can shorten, e.g. by elastic deformation thereof, to compensate for thermally induced expansion, thereby preventing the building up of stress inside the structure 110. The extendible section 115 can e.g. have a relatively low stiffness in plane P of the carrier plate, compared to the rest of the structure 110. For example, the extendible section 115 can comprise a biasing element, arranged for exerting a preload force in plane P of the carrier plate. The biasing element can e.g. be integrated in the structure 110, when the extendible section 115 has a wall that is corrugated and relatively thin, e.g. forming a bellows. Alternatively, or additionally, at least one of the mounts 120 can comprise a biasing element, or be elastically deformable, in plane P of the carrier plate.

[0052] FIG. 4 provides a cross sectional view of an embodiment of a heat exchanger 100, in which the structure comprises a number of compartments 115-1, . . . , 115-N, e.g. two or more than two compartments 115. Here, the extendible section is formed by the compartments 115. The heat exchange surface 111 and the bottom surface are corrugated, folded or bent, thereby providing an elastically deformable mechanism in plane P of the carrier plate.

[0053] Each compartment can comprise a circumferential wall with a top portion, e.g. providing the heat exchange surface 111, and a bottom portion, e.g. providing the bottom surface 112. The top portion and the bottom portion may be interconnected at respective opposing end sections thereof in plane P of the carrier plate. Each of the top and bottom portion can comprise a middle section that is bent outwards with respect to the plane P of the carrier plate. Accordingly, each compartment may comprise an eye-shaped, or diamond shaped cross section, e.g. a cross section that has a long diagonal D.sub.1 and a short diagonal D.sub.2. The long diagonal D.sub.1 can e.g. be in plane P of the carrier plate, while the short diagonal D.sub.2 can be perpendicular to the plane P of the carrier plate. As such, thermal expansion of the heat exchanger 100 in plane P of the carrier plate can be compensated by shortening of the long diagonal D.sub.1 and expansion of the short diagonal D.sub.2. Alternatively, the long and short diagonals D.sub.1, D.sub.2 may be at an angle with respect to the plane P of the carrier plate, e.g. to reduce the expansion of the short diagonal D.sub.2 when the heat exchanger 100 thermally expands in plane P of the carrier plate.

[0054] By reducing the thickness of the circumferential outer wall 113, the thermal mass of the heat exchanger 100 can be reduced, thereby optimizing its efficiency. Moreover, in combination with having a corrugated, folded or bent circumferential outer wall 113, the stiffness of the compartment 115 in plane P of the carrier plate can be decreased, thereby increasing the flexibility of the compartment. In this way, the compartment 115 can extend or shorten in plane P of the carrier plate for compensating thermally induced contraction or expansion of the heat exchanger, by elastic deformation of the. Instead of all compartments 115-1, . . . , 115-N having the same circumferential outer wall 113 design, one or more compartments may have a circumferential outer wall 113 with a relatively low stiffness in plane P of the carrier plate, while other compartments may have a circumferential outer wall 113 with a relatively high stiffness in plane P of the carrier plate. This can e.g. be achieved by varying the wall thickness of the circumferential outer wall 113 between compartments 115. Accordingly, a selected one or more compartments 115 are arranged for forming the extendible section, thus with increased flexibility for compensating thermal expansion of the heat exchanger 100, while other compartments are e.g. designed for structural integrity.

[0055] The compartments 115 can be interconnected by elastic elements 119, that are elastically deformable in plane P of the carrier plate. Accordingly, the seams between compartments, of which the width can be larger or smaller depending on the temperature of the compartments 115, can be sealed by the elastic elements to provide an impervious carrier plate for preventing passage of substrate material through the structure 110.

[0056] The elastic elements can e.g. be made of a bent metal plate or hollow profile, such as a U-profile or an O-profile, to form a thermally conductive, yet elastically deformable connection between compartments 115. Alternatively, the elastic elements 119 can be made of a polymer or rubber material, forming an insulating connection between compartments 115. The heat exchanger 100 can also circumferentially be provided with one or more elastically deformable elements 119, while the compartments are rigidly interconnected, e.g. by a welded or brazed connection.

[0057] As illustrated in FIG. 4, each compartment 115-1, . . . , 115-N can be provided with a channel 150, through which a fluid can flow for heating or cooling the heat exchange surface 111. The channels 150 can for example be made of a material with good thermal conductive properties, e.g. a metal such as an aluminium, steel or copper alloy. The channel 150 can e.g. be made of the same material as the structure 110, or at least as the same material as the circumferential outer wall 113. The wall of the channel 150 may be thermally coupled to the circumferential outer wall 113. When a cooling or heating fluid, such as water or oil, is direct through a channel 150, heat is transferred between the fluid and the substrate 200 via the channel wall and the circumferential outer wall 113. Alternatively, each compartment 115 can itself form a channel for directing a fluid for heating or cooling the heat exchange surface 111.

[0058] The channels 150 can e.g. be part of an energy recovery system, for recovering energy from heat produced by the substrate 200. For example, when cultivating mycelium, heat is produced in the substrate 200 which can be recovered by transferring the heat to a cooling fluid passing through the channels 150. The energy transferred to the cooling fluid can be stored and reused by the energy recovery system, e.g. for heating up a mycelium substrate during its harvesting phase.

[0059] FIG. 5 illustrates a substrate drawer 300, provided with a heat exchanger 100 as described herein. The carrier plate of the heat exchanger 100 is suspended to drawer walls 180. Accordingly, a drawer is formed for containing the substrate 200 and horticultural products 50 cultivated thereon, such as mycelium. The drawer walls 180 are movably mountable to a rack, e.g. by having a bearing arrangement 120 provided on the drawer walls 180. The bearing arrangement may for instance include a planar bearing profile or roller bearings, that engage with respective roller bearings or bearing profiles on the rack. Alternatively, a bearing arrangement can be provided directly on the heat exchanger 100, e.g. on the structure 110 or on the support member 118, for movably mounting the heat exchanger 100 to the rack. The one or more mounts 120, for movably mounting the heat exchanger to the rack, may comprise at least one of: bearings, rails or a carriage or sled.

[0060] FIGS. 6 and 7 illustrate four-level racks 500, wherein each level is provided with a heat exchanger 100 as described herein. In FIG. 6 the heat exchangers 100 are directly suspended to the rack 500, by opposing mounts 120. In FIG. 7, each heat exchanger 100 is provided in a substrate drawer 300, which in turn is suspended in the rack 500 by opposing bearing arrangements 120.

[0061] As described herein, the structure 110 of the heat exchanger 100 is self-supporting for supporting the substrate 200 between the opposing mounts or bearing arrangements 120, such that a bottom surface 112 of the structure 110 opposite the heat exchange surface 111 faces an ambient environment, e.g. an environment between adjacent levels of the rack 500.

[0062] The bottom side of the heat exchanger 100, e.g. the bottom surface 112, can be provided with a light source 190, such as a LED or UV light source, as illustrated in FIG. 6. The light source 190 can e.g. be integrated in the bottom surface 112. Accordingly, the lighting conditions of a lower level substrate and horticultural products 50 cultivated thereon can be controlled. Beneficially, by having the light source 190 directly mounted to or integrated in the bottom side of the heat exchanger 100, waste heat produced by the light source 190 can be dissipated or recovered by the heat exchanger 100. For example, waste heat produced by the light source 190 can be used for heating up the substrate 200, so that less transfer of heat is needed from a heating fluid of the heat exchanger. As such, the efficiency of the heat exchanger 100 can be improved. In contrast, in conventional racks the lighting source is mounted to a bottom plate, which is thermally insulated from the heat exchanger and/or the substrate, and therefore may not contribute to the efficiency of the heat exchanger.

[0063] As shown in FIGS. 6 and 7, the rack may additionally comprise an energy recovery system 400 that is connectable to the heat exchangers 100, for recovering energy from fluid, such as water or oil, obtained from the heat exchangers 100. In this way, the efficiency of the heat exchangers can further be improved.

[0064] It is thus believed that the operation and construction of the present invention will be apparent from the foregoing description and drawings appended thereto. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.

[0065] The invention applies not only to horticultural applications where the heat exchanger is used for temperature control of a substrate, but also to other technical, agricultural or industrial applications where a heat exchanger is used. It will be clear to the skilled person that the invention is not limited to any embodiment herein described and that modifications are possible which may be considered within the scope of the appended claims. Also kinematic inversions are considered inherently disclosed and can be within the scope of the invention. In the claims, any reference signs shall not be construed as limiting the claim.

[0066] The terms comprising and including when used in this description or the appended claims should not be construed in an exclusive or exhaustive sense but rather in an inclusive sense. Thus expression as including or comprising as used herein does not exclude the presence of other elements, additional structure or additional acts or steps in addition to those listed. Furthermore, the words a and an shall not be construed as limited to only one, but instead are used to mean at least one, and do not exclude a plurality. Features that are not specifically or explicitly described or claimed may additionally be included in the structure of the invention without departing from its scope.

[0067] Expressions such as: means for . . . should be read as: component configured for . . . or member constructed to . . . and should be construed to include equivalents for the structures disclosed. The use of expressions like: critical, preferred, especially preferred etc. is not intended to limit the invention. To the extent that structure, material, or acts are considered to be essential they are inexpressively indicated as such. Additions, deletions, and modifications within the purview of the skilled person may generally be made without departing from the scope of the invention, as determined by the claims.