US20230060644A1

US20230060644A1 - Temperature controlled payload container

Info

Publication number: US20230060644A1
Application number: US17/887,812
Authority: US
Inventors: Julian Bell
Original assignee: United Parcel Service of America Inc
Current assignee: United Parcel Service of America Inc
Priority date: 2021-08-26
Filing date: 2022-08-15
Publication date: 2023-03-02
Also published as: CA3227388A1; US20230060684A1; US20230063715A1; US20230061386A1; US12183940B2; US12080907B2

Abstract

A thermally controlled payload container for carrying payloads by an Unmanned Aerial Vehicle (UAV) comprising an inner wall and an outer wall. The inner wall forms a chamber having an open end and a closed end. The payload container also comprises a thermal control body adjacent to the inner wall and disposed between the inner wall and the outer wall. The payload container also comprises a thermoelectric cooler (TEC) extending through the outer wall from a first side of the TEC to a second side of the TEC, the first side adjacent the thermal control body and the second side coupled to an external heat sink.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. Provisional Application No. 63/237,392, filed Aug. 26, 2021, entitled “Pneumatic Platform and Payload Containers for Unmanned Aerial Vehicles.” The aforementioned application is expressly incorporated herein by reference in its entirety.

BACKGROUND

Unmanned Aerial Vehicles (UAVs) are used to deliver goods. Some UAVs are being used to commercially deliver parcels. The majority of deliveries performed by UAVs include relatively small, light parcels.
One current use case for UAV delivery involves delivering critical medical supplies or lab samples. UAVs have significantly reduced the delivery time historically experienced through traditional delivery methods. This has resulted in the faster processing of lab samples and more rapid deployment of critical medical supplies during emergencies.

SUMMARY

This summary is intended to introduce a selection of concepts in a simplified form that is further described in the Detailed Description section of this disclosure. The Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Additional objects, advantages, and novel features of the technology will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the disclosure or learned through practice of the technology.
At a high level, aspects described herein relate to a temperature controlled payload container for carrying payloads. A payload container can include a container suitable for carrying objects for delivery, and may be used in conjunction with delivering payloads using a UAV. The UAV can pick-up and deliver a payload, such as a canister, in the temperature controlled payload container.
To control the temperature, the payload container comprises an inner wall and an outer wall. The inner wall forms a chamber that has an open end and a closed end. In some embodiments, a thermal control body is disposed within the inner and outer wall, and adjacent to the inner wall. The thermal control body may comprise a material with relatively high specific heat (e.g., greater than 3 J/gK) and relatively low density (e.g., less than 1 g/cm³). A thermal electric cooler (“TEC”) extends from a first side that is coupled and/or adjacent to the thermal control body to a second side that is coupled directly or indirectly to an external heat sink. The external heat sink may help facilitate the dissipation of heat, thereby cooling an inner chamber of the payload container and the contents, such as the payload, within it. In another embodiment, the external heat sink may be located in such a way that airflow in the primary direction of flight will similarly facilitate the dissipation of heat from the heat sink to the environment by flowing through fins of the heat sink. Cooling of the inner chamber in this manner may take advantage of the Peltier effect, which generally causes heat to be admitted or absorbed when an electric current passes across a junction of semiconductors between two materials. Taking advantage of the Peltier effect, a TEC having a first side (e.g., a cold side) adjacent or coupled to the thermal control body at a cold junction and a second side (e.g., a hot side) adjacent or coupled to the external heat sink is able to transfer heat from the inner chamber that is absorbed by the thermal control body to the ambient environment outside the payload container.
In other embodiments, the TEC is either not utilized during transit or is absent from the temperature controlled payload container. For example, the TEC may be utilized while the payload container is connected to a power source while docked in order to cool the thermal control body and thereby creating a cold reservoir to keep the contents of the payload container cool without utilizing the TEC during transit.
In another example, the payload container has no TEC or thermal control body and, instead, relies on having a thermal conduction pathway through the payload container to the external heat sink where heat may be dissipated into the ambient environment.
To deliver a temperature controlled payload, the UAV may navigate to a pick-up location and secure a payload within the temperature controller payload container. The payload container may be positioned in such a way that air flow from the principal direction of flight will improve heat transfer between the external heat sink and the ambient environment. The UAV may navigate to another location, which may be the destination of the payload, and ultimately deliver the payload.
Additional objects, advantages, and novel features of the technology will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or learned by practice of the technology.

BRIEF DESCRIPTION OF THE DRAWINGS

The present technology is described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 is an example of a payload container, in accordance with an embodiment described herein;

FIG. 2 illustrates an example payload container utilizing an active cooling system, in accordance with embodiments described herein;

FIG. 3 illustrates an example payload container utilizing a passive cooling system; in accordance with an embodiment described herein;

FIG. 4 is an example of a payload container with a payload secured within; in accordance with an embodiment described herein; and

FIG. 5 is an example of a UAV carrying a payload container with a payload secured within; in accordance with an embodiment described herein.

DETAILED DESCRIPTION

UAVs are utilized for delivering objects, including parcels and laboratory samples. One challenge is the transport of temperature-sensitive objects. This is particularly challenging for certain medical or biological deliverables that are often highly sensitive to temperature. As such, when delivering items using UAVs it can be beneficial for the UAV to provide a temperature controlled environment for temperature-sensitive objects to maintain their integrity upon arrival at a destination.
The present disclosure provides systems and methods that improve aspects of object delivery using UAVs. The technology uses a heat transfer system to facilitate heat transfer from an inner chamber. In another aspect of the technology, an active cooling system is provided that includes TEC cooling of the inner chamber. Some aspects are also particularly useful for delivering objects such as blood or lab samples across healthcare institutions without subjecting them to potentially damaging temperatures. For example, thermoelectric coolers are known for their ability to control temperatures within a fraction of a degree. However, aspects of the current invention not only help improve the ability to control the internal temperature of a payload container, but also help improve the ability to control the temperature more efficiently, for instance by coupling a hot side of a TEC with an external heat sink having fins aligned in the primary direction of flight.
One example payload container for carrying payloads by a UAV includes a payload container comprising an inner wall and an outer wall, the inner wall forming an inner chamber having an open end and a closed end. However, in some embodiments, the thermal control body is integral with the inner wall forming the inner chamber (e.g., the thermal control body defining at least a portion of the inner wall), reducing the conduction path between the inner chamber and an external heat sink. In other embodiments, the inner wall may be separate material coupled, or adjacent to, the thermal control body (e.g., thin metal liner such as aluminum or copper). Between the inner wall and the outer wall is an internal void. The outer wall may comprise a reflective outer surface for reducing radiative heating effects from external sources, such solar radiation. The open end is configured to receive and secure a payload within the payload container. The closed end may also be configured to secure a payload within the payload container (e.g., a bumper). The thermal control body may be disposed in the internal void and adjacent to the inner wall. The thermal control body may comprise a material with relatively high specific heat (e.g., greater than 3 J/gK) and relatively low density (e.g., less than about or less than 1 g/cm³). Example materials suitable for the thermal control body includes water (4.2 J/gK and 1 g/cm³); paraffin wax (3.6 J/gK and 0.7 g/cm³); and the like. However, in some embodiments, there is no thermal control body.
In an embodiment configured to transfer heat out of the inner chamber, the thermal control body being disposed adjacent to the inner wall (e.g., lining the outer surface of the inner wall) allows the thermal control body to absorb heat from the inner chamber conducted through the inner wall. The inner wall may also be made of a relatively thin (e.g., 0.2 mm or thinner) material which may be highly thermally conductive (e.g., aluminum), thus allowing greater transfer of heat from the inner chamber to the thermal control body. However, in some embodiments the inner wall may not be highly thermally conductive (e.g., less than 0.020 W/m·K). A first side of a TEC is coupled to the thermal control body. The TEC further comprises a second side coupled to an external heat sink at a hot junction. This configuration advantageously allows heat to be efficiently transferred to the first side of the TEC from the inner chamber where the TEC transfers the heat to the second side. Heat flows from the first side of the TEC to the second side of the TEC then transfers to the external heat sink where the dissipation of heat is increased by the external heat sink, which may be further facilitated by fins of the heat sink being in alignment with the principal direction of flight. In some embodiments, the heat sink is integral with the outer wall. In other embodiments, the heat sink is insulated from the outer wall (e.g., a layer of insulation or insulative material), thereby reducing heat conduction directly from the outer wall to the heat sink and improving heat conduction out of the inner chamber.
In an embodiment that does not include a TEC, there may be no thermal control body and the inner wall may not be highly thermally conductive (e.g., less than 0.020 W/m·K). In such a configuration, the inner wall may work to prevent heat conduction from the outer wall into the inner chamber relative to other embodiments. The external heat sink may extend through the outer wall and couple directly to the inner wall.
The internal void between the inner wall and the outer wall of the payload container may be hermetically sealed and may comprise a vacuum. The internal void may also comprise insulation with a thermal conductivity less than about 0.020 W/m·K(e.g., silica aerogel). In some cases, the thermal conductivity of the insulation is less than 0.020 W/m·K. Providing insulation in the internal void not only helps reduce the amount of heat that is absorbed from the ambient environment by the inner chamber, but the insulation also helps facilitate heat flow from the TEC to the external heatsink. For example, heat absorbed by the thermal control body from the inner chamber will be more efficiently transferred to the first side of the TEC if insulation is used to reduce the amount of heat that dissipates from the thermal control body into the inner void before reaching the first side of the TEC. The more heat there is flowing to the first side of the TEC, the easier it is for the TEC to transfer heat from the first side to the second side. This is because the TEC has to expend more energy to transfer the same amount of heat when there is a lesser total amount of heat flow to begin with. For example, if the temperature differential between the two sides of the TEC is 10 degrees Celsius, it could require 0.8A to push through 2 W against the temperature gradient. The same system could require 2A to push through 2 W if the temperature differential is 38 degrees Celsius. Therefore, in an embodiment where a relatively cold inner chamber temperature is desired, facilitating heat flow efficiently from the inner chamber to the first side of the TEC will help reduce the temperature differential between the first and second sides of the TEC so that the TEC can function more efficiently to maintain the relatively low temperature inside the inner chamber. The outer wall may comprise a material having a thermal conductivity lower than a thermal conductivity of the thermal control body.
An example range of the thermal conductivity of the thermal control body is from about 0.004 to about 0.020 W/m·K. In some cases, the range is from 0.004 to 0.020 W/m·K. In some embodiments, a thermal conductivity of the outer wall may have a range of about 0.004 to about 0.020 W/m·K. In some cases, the range is from 0.004 to 0.020 W/m·K. In other cases, the thermal conductivity of the outer wall is greater than 0.020 W/m·K. In yet other embodiments, the above ranges are measured as the total thermal conductivity of the payload container as a whole from the inner chamber, along the thermal conduction pathway, which can be dependent upon what specific configuration of materials is used, and to the outer wall. To facilitate heat transfer, the thermal conductivity of the outer wall is lower than the thermal conductivity of the thermal control body. Such a thermal conductivity differential between the outer wall and the thermal control body helps transfer heat away from the inner chamber. In some embodiments, the payload container may comprise an outer wall having a thermal conductivity in a range of 0.004 to 0.020 W/m·K, yet lower than the thermal conductivity of the thermal control body. However, in some embodiments, the outer wall may not have a lower thermal conductivity than the thermal control body. For example, a payload container carrying a frozen laboratory sample in Antarctica may not be as worried about the conduction of heat entering the payload container by way of a warm ambient temperature, but may be more concerned by solar radiation. In such an instance, a highly reflective (e.g., solar reflex index value of 0.65 or greater) outer wall may cause a selection of suitable material (e.g., aluminum) that may not be selected for another payload container operating in different conditions. A reflective outer surface may be applied to an outer wall (e.g., Mylar film) to reflect radiation. For nighttime deliveries near the equator, conductive heat may be more of a more greatly affect material choices. Other variations, and their potential benefits, are also conceived of in light of the specification. The invention may be adapted for various needs without departing from the invention.
Using this configuration, a UAV carrying a payload container can navigate to a pick-up location in order secure a payload within the payload container. The UAV can then navigate away from the pick-up location to another location, which may be a final destination, while controlling the temperature of the objects to be delivered. The UAV may also navigate to a pick-up location in order to secure a payload container containing a payload to the UAV before navigating to another location.
It will be understood that, although the disclosure describes the technology in conjunction with UAVs, some technologies described herein are also suitable for use with ground vehicles or manned vehicles. As such, the disclosed technology should not be limited to only applications involving UAVs, but instead, it should be more broadly interpreted for use with other applications where practical.
With reference now to the figures, FIG. 1 illustrates a high level example of a payload container for carrying payloads in accordance with an embodiment described herein. It should be understood that while payload container 100, and other payload container systems described herein, are described in use with an unmanned systems, the illustrations and associated discussion are meant as examples only, and any of the payload container systems described herein could also be used in conjunction with a manned delivery system.
The payload container 100 comprises an inner wall 102 and an outer wall 104. The inner wall 102 and outer wall 104 may be cylindrical in shape (e.g., tube or hollow cylinder) and define an inner chamber 106 of payload container 100. However, inner wall 102 and outer wall 104 may be round, square, oval, or any other shape. Furthermore, inner wall 102 and outer wall 104 may be different shapes. Inner chamber 106 may be defined by inner wall 102. Inner chamber 106 may have a closed end 108 opposite an open end 110. Closed end 108 may be rounded to form a void of inner chamber 106. In an embodiment where inner wall 102 and outer wall 104 have different shapes, inner wall 102 may not continue to compliment the shape of outer wall 104 as it rounds at closed end 108. Open end 110 may comprise a connection between inner wall 102 and outer wall 104, thereby enclosing an internal void 112 located between inner wall 102 and outer wall 104. An edge of open end 110 may generally correspond in shape to inner wall 102 and outer wall 104 (e.g., cylindrical), and open end 110 provides an access aperture to inner chamber 106. A diameter of the access aperture of open end 110 corresponds to an inner wall edge at open end 110. The open end 110 may receive objects (e.g., payloads, loads, canisters) to be secured and transported within payload container 100. Open end 110 may also be configured to remain permanently open. While depicted as cylindrical, payload container 100 may take the form of another shape. In some embodiments, inner wall 102 may not extend to the edge of open end 110 and, instead, outer wall 104 may have a greater thickness at open end 110 than outer wall 104 has at other locations; or have a change in cross-section to reduce in diameter to meet inner wall 102; such that outer wall 104 forms the entirety of the edge of open end 110 and inner wall 102 is concealed from the ambient environment.
Internal void 112 is located between inner wall 102 and outer wall 104. Internal void 112 may be hermetically sealed and/or comprise a vacuum wherein air has been vacuumed out of internal void 112. The distance between inner wall 102 and outer wall 104 may be from about 1 cm to about 10 cm. In some instances, the distance between inner wall 102 and outer wall 104 is from 1 cm to 10 cm. In another embodiment, the distance between inner wall 102 and outer wall 104 is less than 1 cm. Providing internal void 112 between inner wall 102 and outer wall 104 allows better temperature control than using a single wall to separate a payload from an ambient environment because internal void 112 may be insulated. Forms of both material and/or vacuum insulation are conceived.
Another advantage of providing internal void 112 between inner wall 102 and outer wall 104 is that materials with different properties may be used to form inner wall 102 and outer wall 104. For example, outer wall 104 may comprise materials with low thermal conductivity (e.g., from about 0.004 to about 0.020 W/m·K) to reduce heat flow from outside payload container 100 to within inner chamber 106 while inner wall 102 may comprise materials having high thermal conductivity (e.g., more than 0.020 W/m·K) in order to enhance heat flow from inner chamber 106 to within inner void 112 (e.g., improving conductivity between a payload and a first side of a TEC or heat path leading to external heat sink). However, in some embodiments, inner wall 102 may comprise materials having a thermal conductivity of 0.020 W/m·K or less. Outer wall 104 may comprise a material layer (e.g., greater than 5 mm width) made to withstand the elements and protect cargo (e.g., steel) and a reflective outer surface (e.g., aluminum paint or Mylar film). Additionally, inner wall 102 may comprise a thin material layer (e.g., 0.2 mm or thinner) made of a thermally conducive material (e.g., greater than 0.020 W/m·K).
A heat sink 114 is located external outer wall 104. Heat sink 114 comprises a bottom plate and a series of extensions (e.g., fins alternating with cavities) in alignment extending away from the bottom plate. As depicted in FIG. 1 , an arrangement of the series of extensions shows an increase in the number of extensions in a length-wise direction from closed end 108 to open end 110. However, the arrangement of the series of extensions may also be such that the series of extensions increase in number perpendicular to the length-wise direction. That is, the series of extensions may extend in a lengthwise direction from closed end 108 to open end 110 (for example, as illustrated in FIG. 5 ). The bottom plate is adjacent outer wall 104 and aids in heat exchange from the bottom plate (and thermally connected components) to the series of extensions where the heat dissipates via convection with ambient air. The series of extensions provide increased surface area to enhance a heat exchange between ambient air and the series of extensions along a length of the bottom plate. In order to achieve adequate air flow, the series of extensions may be placed about 0.1 mm to about 5 mm apart. In some instances, the series of extensions are placed 0.1 mm to 5 mm apart.
The specific spacing may further depend upon the specific shape of the payload container. For example, if heat sink 114 has the configuration depicted in FIG. 5 wherein the series of extensions extend radially outward, the series of extensions may be spaced closer together at the point of connection with the bottom plate (e.g., a base portion) and become further spaced apart as they extend radially. Furthermore, a thickness of an individual extension of the series of extensions (e.g., about 0.1 mm to about 5 mm) may be thicker at the base portion than at an end portion (e.g., furthest point away from the bottom plate). In an embodiment where the series of extensions are thicker at the base portion than at the end portion, the thickness may gradually reduce from the base portion to the end portion along substantially an entire length of the series of extensions, or the thickness may be constant from the base portion for a distance that is less than the entire length of an extension and begin to reduce thickness at a location that is between the base portion and the end portion. The series of extensions may also be aligned with the principal direction of flight. For example, an embodiment where the principal direction of flight for payload container 100 is in the direction of closed end 108, heat sink 114 may be in an orientation wherein the series of extensions increase in number radially around at least part of the diameter of payload container 100 and wherein an extension of the series of extensions extends both radially outward and for a distance along a length of payload container 100 that is parallel with the length of payload container 100 from closed end 108 to open end 110.
The bottom plate of heat sink 114 may extend length-wise along outer wall 104 between closed end 108 and open end 110. The series of extensions may be in vertical parallel alignment with one another and increase in number in the length-wise direction along the bottom plate. However, the size, location, and orientation of heat sink 114 depicted in FIG. 1 is a non-limiting example in order to describe aspects of the invention. In an embodiment with a cylindrical payload container, the series of extensions may extend radially around an entire diameter of the payload container and may further extend along substantially an entire length or the entire length of the payload container between closed end 108 and open end 110. Other shapes (e.g., cubical or spherical) for payload container 100 and variations of size, location, and orientation of heat sink 114 similarly corresponding to the other shapes are contemplated within the invention.
Bumper 118 is located near closed end 108 of inner chamber 106. In some examples, bumper 118 may be a cushioned bumper to soften the impact of an object when inserted. Positioning bumper 118 within the chamber may include coupling bumper 118 to inner wall 102 within inner chamber 106. In some cases, the bumper 118 may be coupled to the inner wall at a location within the rounded void of inner chamber 106.
In the example illustrated, the payload container has one or more retaining clamps, such as retaining clamp 122. Generally, the one or more retaining clamps can be used to secure an object within inner chamber 106. As illustrated, retaining clamp 122 is located at open end 110 and also secures the object within inner chamber 106. Retaining clamp 122 having a bias toward a center of inner chamber 106. In some aspects, more than one retaining clamp 122 may be used and may be secured to inner wall 102 within inner chamber 106. Retaining clamp 122 advantageously allows payload container 100 to have an open end 110 configured to remain open while still securing the object.
Vent 120 extends along the length of the container in the example illustrated. Vent 120 may be an air vent. Generally, vent 120 comprises a first open end within inner chamber 106 and a second open end that opens to an area external to outer wall 104, such that air from within inner chamber 106 passes through the first open end, through vent 120, and out of the second open end, and air external to the outer wall 104 passes through the second open end, through vent 120, and into inner chamber 106 via the first opening. The first open end of vent 120 may be positioned proximate the closed end of the payload container 100. This configuration can allow air within inner chamber 106 to be pushed out as an object enters the inner chamber 106 through the open end of the payload container 100. Similarly, the configuration can allow external air to enter the inner chamber 106 at the closed end as the object is removed from within the inner chamber 106 through the open end of the payload container 100, thus reducing or eliminating a potential air lock and permitting easy removal of the load.
Various components and arrangements of FIG. 1 may be used to transport canisters or other objects in a temperature controller manner. This may be done using an active cooling system, which will be described further with respect to FIG. 2 and/or a passive cooling system, which will be described further with respect to FIG. 3 .
Referencing FIG. 2 , an example payload container 200 having an active cooling system is illustrated. Payload container 200 may comprise features or components described in FIG. 1 . Payload container 200 comprises inner wall 202 and outer wall 204, inner wall 202 forms an inner chamber 206 having an open end 210 and a closed end 208. A thermal control body 222 may be adjacent to inner wall 202 and disposed between inner wall 202 and the outer wall 204.
One example active cooling system that may be utilized with this and other arrangements is a thermoelectric cooler (“TEC”) 224. In the example illustrated by FIG. 2 , TEC 224 is adjacent to and extends from thermal control body 222 toward outer wall 204. One example TEC that is suitable is a Peltier module. Other TEC systems may be utilized. As will be understood, many TEC systems, such as Peltier modules, cause heat to flow from one side to another by applying a current through the system. This creates a “hot side” and a “cold side,” where the temperature of the cold side is less than the temperature of the hot side. It will be understood that these are relative terms, and the hot side and cold side may comprise either side of the TEC system based on the direction of current flow.
Payload containers, such as payload container 200 of FIG. 2 are generally described with reference to example use cases in which the temperature of an inner chamber is reduced. However, it will be understood that, in other implementations, such systems may be used to increase the temperature of the inner chamber. For consistency, this disclosure generally uses the terms “cold side” and “hot side,” along with “cold junction” and “hot junction.” Such terms based on implementations where the temperature of an inner chamber is being reduced. However, it should be understood that in other implementations, such as those where the temperature is being increased within the inner chamber, such terms are to be construed so that they are structurally consistent with the understanding that some structural arrangements can be used for cooling or heating the inner chamber using a TEC system based a direction of the current applied to the TEC.
In the example payload container 200 illustrated in FIG. 2 , TEC 224 comprises a cold junction 218 to a hot junction 214. The cold junction 218 is adjacent to or integral with thermal control body 222 and the hot junction 214 is coupled, directly or indirectly, to heat sink 216. In the aspect illustrated, inner wall 202 comprises a first side that is adjacent to inner chamber 206. The first side of inner wall 202 is opposite a second side of inner wall 202. Thermal control body 222 comprises a first side that is adjacent to or integral with the second side of inner wall 202.
While FIG. 2 illustrates TEC 224 directly adjacent to thermal control body 222, in an embodiment, TEC 224 is directly adjacent to inner wall 202. TEC 224 may be directly adjacent to a thermal control body 222 that is integral with an inner wall 202 or TEC 224 may extend through at least a portion of thermal control body 222 and be directly adjacent to inner wall 202.
As illustrated, the first side of thermal control body 222 is opposite a second side of thermal control body 222. TEC 224 comprises a first side (e.g., a cold side) that is adjacent to or integral with the second side of thermal control body 222 at cold junction 218. TEC 224 extends from the first side to a second side (e.g., a hot side) that is indiretly or directly coupled to heat sink 216 at hot junction 214. In the example illustrated, the second side of TEC 224 is indirectly coupled to heat sink 216 via heat path 226, which will be described in more detail. Here, heat path 226 comprises a first side that is adjacent to or inegral with the second side of TEC 224 at hot junction 214. Heat path 226 extends from the first side to a second side that is coupled to heat sink 216. As shown, heat path 226 extends from the first side through outter wall 204. Heat path 226 can be coupled to the heat sink 216 at a location external from inner void 212.
As noted, the arragement provided in FIG. 2 is only one example. In another example arrangment, the first side of TEC 224 (e.g., the cold side) maybe coupled direcly to or be inegral a portion of inner wall 202. In some configurations, the second side of TEC 224 is coupled directly to heat sink 216.
In one embodiment, thermal control body 222 may comprise an insulating material that preferably has a low specific heat (e.g., 0.004 to 0.020 W/m·K) and a low density (e.g., about 1 g/cm³or less) such as styrofoam or another like material. In such an embodiment, inner wall 202 may comprise a thin liner (e.g., aluminum or copper) that is coupled with, or adjacent to, thermal control body 222. Additionally, TEC 224 may be disposed adjacent to inner wall 202 or be coupled with inner wall 202. When thermal control body 222 comprises such a material, TEC 224 may be insulated from thermal control body 222 by the internal void 212, e.g., separated by another material or void. Advantageously, this configuration provides an efficient heat conduction pathway from inner chamber 206, through inner wall 202 and TEC 224, and eventually dissipating into the ambient environment at heat sink 216.
In another embodiment, thermal control body 222 may comprise a material with a high specific heat and low density (e.g., water or paraffin wax) as discussed previously. In such an embodiment, inner wall 202 may comprise a thin liner that is coupled with, or adjacent to, thermal 222. In an embodiment, inner wall 202 may be integral with thermal control body 222 such that thermal control body 222 defines at least a portion of inner wall 202. TEC 224 may be disposed adjacent to, or coupled with, thermal control body 222. In such an embodiment, internal void 212 may further comprise insulation in addition to thermal control body 222 or thermal control body 222 may substantially occupy the entirety of internal void 212 except for TEC 224. In addition to the advantages discussed elsewhere, this embodiment provides further advantages such as being able to remove heat from thermal control body 222 when connected to shore power such that thermal control body 222 may act like an ice pack. During flight, thermal control body 222 may absorb heat that would otherwise transfer to inner chamber 206. Additionally, thermal control body 222 having such qualities would allow for less work to be done by TEC 224 during transit to maintain a relatively cool temperature inside inner chamber 206.
With continued reference to payload container 200, closed end 208 of payload container 200 may be rounded and outer wall 204 may be cylindrical in shape, although other configurations are also contemplated. For example, a pointed end may also provide an aerodynamic design while still being suitable to house other necessary components. The inner wall 202 of FIG. 2 is depicted as being rounded at the closed end 208 and having a similar shape to outer wall 204, however, inner wall 202 may exist in a different configuration (e.g., squared at the closed end 208). For example, the configuration of inner wall 202 could be altered to create more space in internal void 212 between inner wall 202 and outer wall 204 without altering the shape or configuration of outer wall 204. Internal void 212 is a space between inner wall 202 and outer wall 204. Internal void 212 may be hermetically sealed by inner wall 202 and outer wall 204 at open end 210 where inner wall 202 and 204 meet. In some embodiments, internal void 212 may be hermetically sealed and comprise still air or a vacuum. A getter (a metallic compound that absorbs gas molecules) may also be disposed in internal void 212. In other embodiments, internal void 212 comprises insulation (e.g., LI900, aerogel, etc.). The size and shape of internal void 212 is defined by inner wall 202 and outer wall 204. However, in some embodiments, thermal control body 222 may extend integrally from inner wall 202 and be formed of a same material, such that inner wall 202 and thermally insulative material 222 are provided as a unitary component.
Altering the space within internal void 212 may allow for certain portions of internal void 212 to have more insulation or thermal control body 222 than other portions of internal void 212 although the configuration and amount of materials within internal void 212 may be altered without changing the shape of inner wall 202 and outer wall 204. Depending on the intended use, as discussed previously in relation to operation in different environments, a suitable configuration of insulation and thermal control body 222 may be selected. For example, as opposed to a configuration in which equal amounts or a uniform distribution of insulation is disposed throughout internal void 212, greater amounts of insulation may be used in a portion of internal void 212 near closed end 208 and/or open end 210. Such a configuration may provide better insulating properties when payload container 200 is being carried by a UAV and traveling in a direction where a head wind is hitting closed end 208 than a configuration with less insulation near closed end 208. In some embodiments, a portion of inner wall 202 may be exposed to the ambient environment at open end 210. Providing additional insulation in a portion of internal void 212 near open end 210 reduces the rate of heat transfer from the ambient environment to within payload container 200 at a position where a portion of inner wall 202 may be exposed to the ambient environment. Furthermore, portions of inner void 212, through which thermal control body 222 does not extend, may have additional insulation disposed within in order to prevent heat from collecting in areas that are away from TEC 224 or thermal control body 222. By altering the configuration of inner wall 202 and outer wall 204, and/or altering the disposition of components within internal void 212, suitable configurations can be implemented which work to control the transfer of heat from inner chamber 206 to heat sink 216 with minimal heat loss along its path.
Additionally, inner wall 202 and/or thermal control body 222 could be shaped to increase surface area of the inner wall 202 with internal void 212 and inner chamber 206. For example, an inner surface of inner wall 202 (e.g., on the first side of inner wall 202) facing inner chamber 206 may comprise a series of peaks and valleys or other textured shape to increase surface area between inner chamber 206 and inner wall 202. Increased surface area may improve the efficiency of TEC 224thermal control body. However, the inner surface of inner wall 202 may also have a smooth and/or non-textured surface when, for example, inner wall 202 is configured to be in contact with a payload secured within payload container 200 (e.g., the payload has a smooth outer surface). In such a configuration, the payload having more points of contact with inner wall 202 may, in some situations, provide better heat flow from the payload (such as a canister) within inner chamber 206 through inner wall 202 to thermal control body 222 compared to a configuration providing more overall surface area between inner chamber 206 and inner wall 202 (e.g., ridges). An outer surface of inner wall 202 facing internal void 212 may have similar configurations as those discussed with the inner surface of inner wall 202 (e.g., ridges or smooth). For example, the inner surface of inner wall 202 may comprise a series of valleys and peaks to increase surface area between inner wall 202 and inner chamber 206. Inner wall 202 may be thermally conductive (e.g., made from a material like aluminum or copper, with K=200-400 W/m-K) to assist in the transfer of heat out of the inner chamber into the thermal material 222. However, to minimize heat transfer from the outer wall 204 back into the inner wall 202 via their junction, the inner wall may be very thin (e.g., 0.2 mm or less) to provide a minimal conduction path to the outer wall.
Inner wall 202 and/or thermal control body 222 may define the shape of inner chamber 206. When payload container 200 has a cylindrical shape (as in FIG. 2 ), inner wall 202 may define a diameter of inner chamber 206 between opposite sides of inner wall 202 from open end 210 to closed end 208. The distance between opposite sides of inner wall 202 (e.g., diameter of inner chamber 206) may be greater at open end 210 than at other portions along inner chamber 206. The distance between opposite sides of inner wall 202 may decrease where inner wall 202 begins to round at closed end 208, eventually decreasing to zero at the furthermost edge of the rounding at closed end 208. At a portion of inner wall 202 at open end 210, the distance between opposite sides of inner wall 202 may increase and eventually couple to outer wall 204.
Outer wall 204 comprises an inner surface (e.g. on the first side of outer wall 204) facing internal void 212 and an outer surface facing the ambient environment. In embodiments where insulating internal void 212 includes vacuum insulation, outer wall 204 may have a vacuum port 230 providing access to internal void 212 through outer wall 204. For example, in an embodiment where internal void 212 is primarily comprised of thermal control body 222 and TEC 224, the space between thermal control body 222 and/or inner wall 202 and outer wall 204 may be from 0.5 mm to 5 mm. In such an embodiment, it may be advantageous to apply vacuum insulation through vacuum port 230. Getters may also be disposed in internal void 212 to improve the lifespan and performance of the vacuum.
The entirety of outer wall 204 or just the outer surface of outer wall 204 may comprise an external shield or material with high reflectivity to minimize radiative uptake (e.g., aluminum foil, white paint, Mylar, etc.). Outer wall 204 may vary in thickness between different embodiments and within the same embodiment. For example, an embodiment where the conduction of heat entering payload container 200 through outer wall 204 could occur during use, it may be beneficial to use a material with a relatively low thermal conductivity (e.g., from about 0.004 to about 0.020 W/m·K) that is relatively thick (e.g., greater than 5 mm) in order to keep heat from entering payload container 200. In another embodiment where heat uptake due to radiation could occurring during use, a relatively thinner (e.g., less than 5 mm) and lightweight material (e.g., between 2 g/cm³and 3 g/cm³) which is highly reflective of radiation may be used to efficiently control the flow of heat while having a lesser overall weight. By weighing less, payload container 200 may be more easily carried by a UAV. Furthermore, the outer surface of outer wall 204 may comprise a layer of reflective material (e.g., paint or foil) applied on outer wall 204. Within a particular embodiment, the thickness of outer wall 204 may vary as well. For example, outer wall 204 may be thicker at open end 210 where outer wall 204 couples to inner wall 202. The coupling of outer wall 204 to inner wall 202 at open end 210 may hermetically seal internal void 212 between outer wall 204 and inner wall 202. Providing a thicker outer wall 204 having heat resistant properties (e.g., low thermal conductivity and/or reflectivity) at this location provides better insulation for payload container 200 at open end 210 because it exposes less of inner wall 202 (and/or thermal control body 222) and/or increases the distance between inner wall 202 and the ambient environment.
In embodiments, thermal control body 222 may be disposed within internal void 212 and adjacent inner wall 202 along part, all, or substantially all of the length of inner wall 202. Thermal control body 222 may be in physical contact with the outer surface of inner wall 202 or may be in proximity (e.g., less than 0.5 mm). In some cases, thermal control body 222 does not contact the outer surface of inner wall 202. For example, in an embodiment where the outer surface of inner wall 202 comprises a series of peaks and valleys to increase surface area, thermal control body 222 may be disposed to contact the outer surface of inner wall 202 throughout the series of peaks and valleys in order to increase the area at which heat may be absorbed by thermal control body 222. A thickness of thermal control body 222 may remain constant or may vary at different points within internal void 212. Thermal control body 222 may comprise a material with a specific heat greater than 3 J/gK and a density less than 1 g/cm³. Examples of suitable materials to be used include foams. The thermal conductivity of thermal control body 222 may be about 0.004 to about 0.020 W/m·K. In some cases, the thermal conductivity of thermal control body 222 is 0.004 to 0.020 W/m·K. Such specific heat is advantageous as it allows thermal control body 222 to act as a reservoir that is able to absorb large amounts of heat from inner chamber 206, thus allowing TEC to operate more efficiently. The density noted above allows for an overall lighter payload container 200.
The range of thermal conductivity suitable for thermal control body 222 provides benefits for payload container 200. For example, thermal control body 222 conducts heat well enough to absorb heat from inner chamber 206 through inner wall 204, but also well enough to efficiently transfer the absorbed heat to the cold side of TEC 224. The ability of thermal control body 222 to absorb heat from inner chamber 206 may be enhanced when thermal control body 222 is in contact and/or coupled to inner wall 202, where inner wall 202 is made of a liner with high thermal conductivity (e.g., an aluminum alloy or copper). Therefore, thermal conductivity in a range of about 0.004 to about 0.020W/m·K, high specific heat, and low density are properties possessed by thermal control body 222 in order to effectively absorb heat from inner chamber 206 and transfer the absorbed heat to the cold side of TEC 224.
TEC 224, as noted, may comprises a Peltier element and have a cold side at a cold junction 218 with thermal control body 222, and a hot side at a hot junction 214 with a heat path 226, with heat path 226 coupled to a heat sink 216. As an electrical current flows, heat is transferred from the cold side to the hot side. In an embodiment where thermal control body 222 defines inner chamber 206 (e.g., in the absence of inner wall 202) or where thermal control body 222 is adjacent or coupled to substantially an entirety of the outer facing surface of inner wall 202, TEC 224 may advantageously be disposed in various locations while retaining a connection to the thermal conduction pathway. This is advantageous with regard to payload container 200 because the location of heat sink 216 affects the amount of air velocity that passes over heat sink 216 during operation. Therefore, one or more TECs 224 may be placed in positions and/or orientations that receive the most air velocity (e.g., when the series of extensions of heat sink 216 are aligned with the principal direction of flight) while still effectively conducting heat from substantially an entire surface area of inner chamber 206.
In an example TEC comprising a Peltier element, the Peltier element comprises one or more devices with a cold side and a hot side. Between the two sides are semiconductors. The cold side and the hot side are generally made from materials with high thermal conductivity (e.g., greater than 100 W/m·K) but also low electrical conductivity (e.g., 10⁻²to 10⁻³S/cm). An example of a material used for the sides of Peltier element 224 include dielectric ceramic plates. This advantageously allows for Peltier element 224 to efficiently use an electric current to transfer heat from the cold side to the hot side without diminishing the electrical current or the transferred heat returning back to the cold side. The cold side of Peltier element is adjacent to and/or coupled with thermal control body 222 at cold junction 218 to allow for enhanced heat transfer between thermal control body 222 and the cold side. The hot side of Peltier element is adjacent to and/or coupled with heat path 226 at hot junction 214 to allow for enhanced heat transfer between heat path 226 and the hot side.
Heat path 226 extends from hot junction 214 through outer wall 204 and is coupled to heat sink 216. Heat path 226 may comprise a material with high thermal conductivity (e.g., greater than 100 W/m·K) in order to efficiently transfer heat between the hot side and the heat sink 216. As it is a desire to push as much heat through TEC 224 (i.e., higher temperature differentials between heat sink 216 and the ambient environment causes more heat to dissipate and inner chamber 206 to reach lower temperatures), heat path 226 allows heat to move from TEC 224. Heat path 226 may comprise a heat pipe or other suitable configurations to efficiently transfer heat.
Heat sink 216 is located external to outer wall 204 and may comprise similar materials as heat path 226. In some embodiments, heat path 226 and heat sink 216 are not separate components but are made as a single component where heat path 226 integrally extends from heat sink 216. Heat sink 216 may comprise a bottom plate located adjacent to outer wall 204 and coupled to heat path 226. Having such a bottom plate allows heat sink 216 not only to absorb heat from heat path 226, but also absorb heat that dissipates from the hot side of TEC 224 but is uncaptured by heat path 226 and that may be absorbed by a portion of outer wall 204 located near TEC 224. In some embodiments, TEC 224 may be integral with outer wall 204. However, in other embodiments, TEC 224 may be separate and insulated from outer wall 204. Providing material insulation between TEC 224 and outer wall 204 is advantageous for reducing the connection of outer wall 204 with the thermal conduction pathway.
Extending from the bottom plate of heat sink 216 are a series of extensions (e.g., fins with alternating cavities) providing increased surface area to heat sink 216. The extensions may be aligned vertically and sufficient distance between them to allow sufficient air flow (e.g., 0.1 mm to 5 mm). An optimal balance between surface area and air flow is desired. Air existing between extensions may represent the ambient air temperature. The higher the ambient air temperature, the less efficiently TEC 224 may cool the inside of the payload container 200.
A power source 220 provides an electrical current for TEC 224. Power source 220 may comprise any power source suitable for generating an electrical current (e.g., batteries, solar power, hydro fuel cell, combustion engine, etc.). For example, power source 220 may be a rechargeable battery included in the system of payload container 200. However, power source 220 supplying an electrical current may come from a UAV carrying payload container 200. While illustrated as having wired connection extending through outer wall 204, it will be understood that power source 220 may be electrically coupled to any one or more TEC elements in any configuration.
Still referring to FIG. 2 , in an example embodiment in which heat is being transferred out of inner chamber 206, the cool side of TEC 224 would be adjacent, and coupled to, thermal control body 222 at cold junction 218. The hot side of TEC 224 would be adjacent, and coupled to, heat path 226 at hot junction 214. Heat path 226 extends from hot junction 214 through outer wall 204 and connects to heat sink 216 external outer wall 204.
In this example configuration, TEC 224 may receive an electric current from power supply 220 and move heat from the cool side to the hot side of TEC 224. As heat is drawn away from the cool side, a temperature differential increases between the cool side and thermal control body 222 causing heat from thermal control body 222 to be transferred to the cold side across cold junction 218. As heat begins to flow to the cool side from thermal control body 222 at cold junction 218, a temperature differential increases between thermal control body 222 and inner wall 202 causing heat from inner wall 202 to flow to thermal control body 222. As heat flows through thermal control body 222 from inner wall 202, a temperature differential increases between inner wall 202 and inner chamber 206 causing an increase in heat flow from inner chamber 206 to inner wall 202 (or straight to thermal control body 222 in embodiments without inner wall 202). Ultimately, heat is transferred from objects within inner chamber 206 to internal void 212.
Continuing with the example configuration, heat from the cold side of TEC 224 is eventually dissipated external to outer wall 204 (e.g., to ambient air surrounding payload container 200. In in doing so, TEC 224 transports heat from the cool side to the hot side. This creates a temperature differential between the hot side of TEC 224 and heat path 226, causing heat to flow to increase from the hot side of TEC 224 to heat path 226. As heat path 226 absorbs energy from the hot side of TEC 224, a temperature differential increases between heat path 226 and heat sink 216 causing heat flow to increase from heat path 226 to heat sink 216. Finally, the heat may dissipate from heat sink 216 to the outside environment.
Dissipation of heat from heat sink 216 to the outside environment may occur with still air and/or be enhanced by air flowing over heat sink 216 due to movement of a UAV carrying payload container 200. The orientation and location of payload container 200 and/or heat sink 216 relative to the direction of flight may also result in increased air velocities across heat sink 216. In this way, activation of TEC 224 begins facilitates drawing heat from inner chamber 206 and dissipating it outside of payload container 200.
This example illustrates a payload container system that is able provide heat removal from within a payload container. However, it can be appreciated that changing the direction of heat flow by TEC 224 will result in payload container 200 transferring heat from the outside environment to inner chamber 206. The benefits of components and/or their material compositions described in relation to withdrawing heat from inner chamber 206 are also applicable in relation to transferring heat to inner chamber 206.
Turning now to FIG. 3 , an example payload container 300 is illustrated. Payload container 300 uses a passive heat transfer system to facilitate heat transfer away from an inner chamber 306. In order to accomplish this, payload container 300 comprises an inner wall 304, an outer wall 304, inner chamber 306, a closed end 308, an open end 310, an internal void 312, a heat sink 316, a heat path 326, and a vacuum port 330. The components comprising payload container 300 may have the same or similar features as described in relation to counterpart components in FIGS. 1 and 2 . As such, with regard to the discussion of FIG. 3 , the previous discussion of similar components at least up to this point should be incorporated herein and will be understood to apply to corresponding components of FIG. 3 .
In order to reduce heat transfer into inner chamber 306, payload container 300 comprises an inner wall 302 and an outer wall 304, where inner wall 302 forms inner chamber 306, and where inner chamber 306 has a closed end 308 and an open end 310. An internal void 312 may be hermetically sealed by inner wall 302 and outer wall 304. Internal void 312 may comprise insulation (e.g., material or vacuum insulation) as well as getters. Inner wall 302 may comprise materials with a thermal conductivity of about 0.020 W/m·K or less to further reduce heat conduction from outer wall 306 through inner wall 302. A heat path 326 may couple to inner wall 302 and extend through outer wall 304 to a heat sink 316. Heat path 326 may be integral with heat sink 316, or they may be formed as separate components coupled together. Furthermore, heat path 326 and heat sink 316 may be integral with outer wall 304, or they may be formed as separate components from outer wall 304. In some embodiments, outer wall 304 is insulated from heat path 326 and heat sink 316.
Referring to an example embodiment as depicted in FIG. 3 in which heat is being transferred out of inner chamber 306, the heat may flow through an at least partially insulated thermal conduction pathway (e.g., internal void 312) and dissipate into the ambient environment external payload container 300. For example, as a result of heat dissipating into the ambient environment from heat sink 316 heat flow from inner chamber 306 to heat sink 316 may be increased. As heat sink 316 dissipates heat, heat begins to flow from heat path 326 to heat sink 316. Continuing, heat also begins to flow from inner wall 302 to heat path 326 and from inner chamber 306 to inner wall 302. Ultimately, heat flows out of inner chamber 306 to heat sink 316 along the thermal conduction pathway. Furthermore, even in a situation where inner chamber 306 is cool enough that heat is not flowing to heat sink 316, an embodiment as depicted in FIG. 3 will help keep inner chamber 306 cool.
Alternatively, or in addition, to heat dissipation at heat sink 316, payload container 300 may experience heat flow into inner chamber 306 such that a heat flow begins from inner chamber 306 to inner wall 302. The heat continues to flow from inner wall 302, through heat path 326, and eventually flowing to heat sink 316. The heat may dissipate into the ambient environment from heat sink 316, thus enhancing the flow of heat out of inner chamber 306 further.
Turning now to FIG. 4 , an example payload container 400 with a payload 418 secured within is illustrated. Payload container 100 of FIG. 1 , payload container 200 of FIG. 2 , and payload container 300 of FIG. 3 are example payload container suitable for use as payload container 400. Payload 418 may be any object to be transported in payload container 400. As illustrated in FIG. 4 , payload 418 is generally cylindrical with seal 408A located near open end 412. Payload container 400 may be configured such that seal 408A of payload 418 may contact inner wall 416 to restrict the movement of air in and out of payload container 400 through open end 412. Heat sink 406 may generally be disposed along outer wall 404 and extend through outer wall 404 to within payload container 400. In some embodiments, payload 418 comprises seal 408B near closed end 414. heat sink 406 may be disposed in an area along payload container 400 that is between seal 408A and seal 408B. The area between seal 408A and seal 408B may define cooled portion 410 of the payload container 400. Cooled portion 410 may also be defined by inner wall 416 of payload container 400. Cooled portion 410 may also be defined by the body of payload 418 between seal 408A and seal 408B.
Heat sink 406 may be disposed between seal 408A and seal 408B when payload 418 is secured within payload container 400. Such positioning allows heat sink 406 to facilitate heat transfer away from payload 418 using any of the active or passive method previously discussed. The temperature of cargo within payload 418 being carried by payload container 400 may be effectively controlled as well if the cargo is confined to the portion of payload 418 within cooled portion 410. For example, payload 418 may comprise components which are structured to insulate, protect, and/or grant access to the cargo space within payload 418 beyond seal 408A and seal 408B, however, the area between seal 408A and 408B on payload 418 may actually contain the cargo when payload 418 is secured within payload container 400. This configuration allows effective control the temperature of the cargo of payload 418 without requiring a cap or lid over open end 412.
FIG. 5 illustrates a payload container 502 that may be permanently or removably coupled to a UAV 500. Any payload container described herein may be used as payload container 502. More than one payload container 502 may be coupled to UAV 500. In the example illustrated in FIG. 5 , payload container 502 is coupled to UAV 500 and positioned beneath the body of UAV 500, however, payload container 502 may be secured at other locations or orientations to UAV 500. Payload container 500 may comprise components that are similar to and correspond to components of those payload containers already discussed. Payload container 500 may be use any of, and comprise the components used with, the active or passive cooling systems and techniques previously described.
Payload container 502 comprises a payload 504 secured within and a heat sink 506 exposed to the ambient environment on an outside of payload container 502. In the example illustrated, heat sink 506 comprises a series of extensions. The series of extensions extends along payload container 502 in a direction from closed end 510 and open end 512. Payload container 502 may be coupled to UAV 500 in a manner such that the series of extensions is aligned with the principal direction of flight of UAV 500. While UAV 500 is traveling, an increase in air flow in th principal direction of flight may be experienced by payload container 502.
In some embodiments, heat sink 506 may extend around an entirety or substantially all of an entirety of a body of payload container 502. For example, when payload container 502 is cylindrical in shape, having two circular ends such as closed end 510 and open end 512 and a curved lateral surface between the circular ends, heat sink 506 may extend around an entirety or substantially all of an entirety of the curved lateral surface of payload container 502.
An orientation of heat sink 506 may be such that a series of extensions of the external heat sink increase in number in a circumferential direction perpendicular to both an axial direction and radial direction of payload container 502 as heat sink 506 extends around the curved lateral surface of payload container 502. This example embodiment may advantageously allow easier aircraft movement. Furthermore, such an orientation of heat sink 506 and its positioning around a circumference of the curved lateral surface of payload container 502 allows for increased air flow in the principal direction of flight through the external heat sink while UAV 500 is in operation, thus increasing the ability of payload container 502 to dissipate heat from within payload container 502 to the ambient environment.
UAV 500 may be used to transport payload 504 in the temperature controlled environment of payload container 502. For example, UAV 500 may be navigated to a first location to pick-up payload 504. UAV 500 may or may not already be coupled to payload container 502, and payload 504 may or may not already be in payload container 502. UAV 500 may be configured to carry multiple payload containers 502 in multiple orientations. After payload 504 is secured within payload container 502, payload container 502 being located outside of rotor wash area 508, UAV 500 may navigate towards another location.
During operation, payload container 502 control, or otherwise modify, the temperature of payload 504 within. To aid in this process, heat sink 506 may be located on the outside of payload container 502 and configured such that the series of extensions of the external heat sink 506 extend in a circumferential direction around the curved surface of payload container 502. As UAV 500 travels, heat sink 506 is exposed to increased air flow in the principal direction of flight and the ability to control the temperature within payload container 502 may be further enhanced by increased flow across the series of extensions when the series of extensions are aligned (e.g., parallelly aligned length-wise) with the principal direction of flight. For example, as depicted in FIG. 5 , the series of extensions are aligned when the principal direction of flight is in a direction pointing the same way as closed end 510.
Embodiments described above may be combined with one or more of the specifically described alternatives. In particular, an embodiment that is claimed may contain a reference, in the alternative, to more than one other embodiment. The embodiment that is claimed may specify a further limitation of the subject matter claimed.
The subject matter of the present technology is described with specificity herein to meet statutory requirements. However, the description itself is not intended to limit the scope of this disclosure. Rather, the inventors have contemplated that the claimed or disclosed subject matter might also be embodied in other ways, to include different steps or combinations of steps similar to the ones described in this document, in conjunction with other present or future technologies. Moreover, although the terms “step” or “block” might be used herein to connote different elements of methods employed, the terms should not be interpreted as implying any particular order among or between various steps herein disclosed unless and except when the order of individual steps is explicitly stated.
In addition, words such as “a” and “an,” unless otherwise indicated to the contrary, include the plural as well as the singular. Thus, for example, the constraint of “a feature” is satisfied where one or more features are present. Also, the term “or” includes the conjunctive, the disjunctive, and both (a or b thus includes either a or b, as well as a and b).
From the foregoing, it will be seen that this technology is one well adapted to attain all the ends and objects described above, including other advantages that are obvious or inherent to the structure. It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims. Since many possible embodiments of the described technology may be made without departing from the scope, it is to be understood that all matter described herein or illustrated the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
Some example aspects that can be practices from the foregoing description include the following:
Aspect 1: A payload container for carrying loads by an Unmanned Aerial Vehicle (UAV), the payload container comprising: an inner wall and an outer wall, the inner wall forming a chamber having an open end and a closed end; a thermal conductive material adjacent to the inner wall and disposed between the inner wall and the outer wall; and a thermal electric cooler extending through the outer wall from a cold junction to a hot junction of the thermoelectric cooler, the cold junction coupled to the thermal control body and the hot junction coupled to an external heat sink.
Aspect 2: Aspect 1, wherein an internal void between the inner wall and the outer wall comprises a vacuum.
Aspect 3: Any of Aspects 1-2, wherein an internal void between the inner wall and the outer wall comprises insulation with an R value equal to or greater than 2.
Aspect 4: Any of Aspects 1-3, wherein the outer surface comprises a reflective material.
Aspect 5: Any of Aspects 1-4, wherein the outer wall comprises a material having a thermal conductivity lower than a thermal conductivity of the thermal control body.
Aspect 6: Any of Aspects 1-5, wherein a thermal conductivity of the thermal control body is from about 0.004 to about 0.020 W/m·K.
Aspect 7: Any of Aspects 1-6, wherein an internal void between the inner wall and the other wall is hermetically sealed.
Aspect 8: An unmanned aerial vehicle (UAV) comprising: a payload container for carrying loads by the UAV, the payload container comprising: an inner wall and an outer wall, the inner wall forming a chamber having an open end and a closed end; a thermal conductive material adjacent to the inner wall and disposed between the inner wall and the outer wall; and a thermal electric cooler extending through the outer wall from a cold junction to a hot junction of the thermoelectric cooler, the cold junction coupled to the thermal control body and the hot junction coupled to an external heat sink.
Aspect 9: Aspect 8, wherein an internal void of the payload container between the inner wall and the outer wall comprises a vacuum.
Aspect 10: Any of Aspects 8-9, wherein an internal void between the inner wall and the outer wall comprises insulation with an R value equal to or greater than 2.
Aspect 11: Any of Aspects 8-10, wherein the outer surface comprises a reflective
material.
Aspect 12: Any of Aspects 8-11, wherein the outer wall comprises a material having a thermal conductivity lower than a thermal conductivity of the thermal control body.
Aspect 13: Any of Aspects 8-12, wherein a thermal conductivity of the thermal control body is from about 0.004 to about 0.020 W/m·K.
Aspect 14: Any of Aspects 8-13, wherein an internal void between the inner wall and the outer wall is hermetically sealed.
Aspect 15: A method of temperature controlled delivery, the method comprising: navigating an unmanned aerial vehicle (UAV) from a first location to a second location, the payload container comprising: an inner wall and an outer wall, the inner wall forming a chamber having an open end and a closed end; a thermal conductive material adjacent to the inner wall and disposed between the inner wall and the outer wall; and a thermal electric cooler extending through the outer wall from a cold junction to a hot junction of the thermoelectric cooler, the cold junction coupled to the thermal control body and the hot junction coupled to an external heat sink; at the second location, securing a payload within the payload container; and navigating the UAV having the payload within the payload container away from the second location.
Aspect 16: Aspect 15, wherein the payload container further comprises an internal void between the inner wall and the outer wall, and wherein the internal void comprises a vacuum.
Aspect 17: Any of Aspects 15-16, wherein an internal void between the inner wall and the outer wall comprises insulation with an R value equal to or greater than 2.
Aspect 18: Any of Aspects 15-17, wherein the outer surface comprises a reflective material.
Aspect 19: Any of Aspects 15-18, wherein the outer wall comprises a material having a thermal conductivity lower than the thermal control body.
Aspect 20: Any of Aspects 15-19, wherein a thermal conductivity of the thermal control body is from about 0.004 to about 0.020 W/m·K.

Claims

What is claimed is:

1. A payload container for carrying loads, the payload container comprising:

an inner wall and an outer wall, the inner wall forming a chamber having an open end and a closed end;

a heat sink positioned on the outer wall;

a thermal control body extending from the inner wall and disposed between the inner wall and the outer wall; and

a thermal electric cooler (TEC) extending from a first side of the TEC to a second side of the TEC, the first side of the TEC adjacent to the inner wall and the second side of the TEC coupled to the heat sink.

2. The payload container of claim 1, wherein an internal void between the inner wall and the outer wall comprises a vacuum.

3. The payload container of claim 1, wherein the heat sink comprises a series of extensions extending from the closed end to the open end.

4. The payload container of claim 1, wherein an outer surface of the outer wall comprises a reflective material.

5. The payload container of claim 1, wherein the outer wall comprises a material having a thermal conductivity lower than a thermal conductivity of the thermal control body.

6. The payload container of claim 1, wherein a thermal conductivity of the thermal control body is from about 0.004 to about 0.020 W/m·K.

7. The payload container claim 1, wherein an internal void disposed between the inner wall and the outer wall is hermetically sealed.

8. An unmanned aerial vehicle (UAV) comprising:

a payload container for carrying loads by the UAV, the payload container comprising:

a heat sink positioned on the outer wall;

9. The UAV of claim 8, wherein an internal void of the payload container between the inner wall and the outer wall comprises a vacuum.

10. The UAV of claim 8, wherein the heat sink comprises a series of extensions extending from the closed end to the open end.

11. The UAV of claim 8, wherein an outer surface of the outer wall comprises a reflective material.

12. The UAV of claim 8, wherein the outer wall comprises a material having a thermal conductivity lower than a thermal conductivity of the thermal control body.

13. The UAV of claim 8, wherein a thermal conductivity of the thermal control body is from about 0.004 to about 0.020 W/m·K.

14. The UAV of claim 8, wherein an internal void between the inner wall and the outer wall is hermetically sealed.

15. A method of temperature controlled delivery, the method comprising:

navigating an unmanned aerial vehicle (UAV) from a first location to a second location, the UAV having a payload container coupled thereto, the payload container comprising:

a heat sink positioned on the outer wall;

a thermal electric cooler (TEC) extending from a first side of the TEC to a second side of the TEC, the first side of the TEC adjacent to the inner wall and the second side of the TEC coupled to the heat sink;

at the second location, securing a payload within the payload container; and

navigating the UAV having the payload within the payload container away from the second location.

16. The method of claim 15, wherein the payload container further comprises an internal void between the inner wall and the outer wall, and wherein the internal void comprises a vacuum.

17. The method of claim 15, wherein the heat sink comprises a series of extensions extending from the closed end to the open end.

18. The method of claim 15, wherein an outer surface of the outer wall comprises a reflective material.

19. The method of claim 15, wherein the outer wall comprises a material having a thermal conductivity lower than a thermal conductivity of the thermal control body.

20. The method of claim 15, wherein a thermal conductivity of the thermal control body is from about 0.004 W/m·K to about 0.020 W/m·K.