Thermoelectric power generation using radiant and conductive heat dissipation

A thermoelectric power generation system includes a solar panel array on a first side of a tower to absorb solar radiation and generate electrical energy and waste heat and a panel on a second side, opposite the first side, of the tower. A plurality of thermoelectric elements of the tower are interposed between the solar panel array and the panel. The plurality of thermoelectric elements converts conductive heat flow of the waste heat from the solar panel directed toward the panel to electrical energy. A conductive base supports the tower and to conduct heat away from the panel.

BACKGROUND

Exemplary embodiments pertain to the art of power generation and, in particular, to thermoelectric power generation using radiant and conductive heat dissipation.

On-site power generation presents both an opportunity and a challenge in space travel. Power generation capability reduces the need to carry bulky power storage devices that add to launch costs. Yet, many types of power generation used on earth are impractical due to the extreme environment of space or are impractical due to inefficiency.

BRIEF DESCRIPTION

In one embodiment, a thermoelectric power generation system includes a solar panel array on a first side of a tower to absorb solar radiation and generate electrical energy and waste heat, and a panel on a second side, opposite the first side, of the tower. A plurality of thermoelectric elements of the tower are interposed between the solar panel array and the panel. The plurality of thermoelectric elements being converts conductive heat flow of the waste heat from the solar panel directed toward the panel to electrical energy. A conductive base supports the tower and to conduct heat away from the panel.

Additionally or alternatively, in this or other embodiments, the thermoelectric power generation system also includes insulating material between the solar panel array and the panel around the thermoelectric elements.

Additionally or alternatively, in this or other embodiments, the thermoelectric power generation system also includes a gimbal to control an orientation of the tower.

Additionally or alternatively, in this or other embodiments, the gimbal is changes a position of the tower in a first dimension and in a second dimension, perpendicular to the first dimension.

Additionally or alternatively, in this or other embodiments, the thermoelectric power generation system also includes a controller to control the gimbal.

Additionally or alternatively, in this or other embodiments, the conductive base is aluminum.

Additionally or alternatively, in this or other embodiments, the panel is aluminum, copper, steel, a conductive polymer, or a conductive composite.

Additionally or alternatively, in this or other embodiments, the panel includes a coolant channel for convective heat transfer from the panel.

Additionally or alternatively, in this or other embodiments, the conductive base includes a second coolant channel for convective heat transfer from the conductive base.

Additionally or alternatively, in this or other embodiments, the conductive base includes a second coolant channel for convective heat transfer from the conductive base.

In another embodiment, a method of assembling a thermoelectric power generation system includes forming a first side of a tower with a solar panel array to absorb solar radiation and generate electrical energy and waste heat and forming a second side of the tower, opposite the first side, with a panel. The method also includes disposing a plurality of thermoelectric elements between the solar panel array and the panel. The plurality of thermoelectric elements converts conductive heat flow of the waste heat from the solar panel directed toward the panel to electrical energy. A conductive base is attached to the tower to support the tower and to conduct heat away from the panel.

Additionally or alternatively, in this or other embodiments, the method also includes disposing insulating material between the solar panel array and the panel around the thermoelectric elements.

Additionally or alternatively, in this or other embodiments, the method also includes arranging a gimbal between the base and the tower to control an orientation of the tower.

Additionally or alternatively, in this or other embodiments, the arranging the gimbal includes configuring the gimbal to change a position of the tower in a first dimension and in a second dimension, perpendicular to the first dimension.

Additionally or alternatively, in this or other embodiments, the method also includes configuring a controller to control the gimbal.

Additionally or alternatively, in this or other embodiments, the attaching the conductive base includes attaching an aluminum base to the tower.

Additionally or alternatively, in this or other embodiments, the attaching the conductive base to the tower includes attaching the conducting base to the panel at a first end.

Additionally or alternatively, in this or other embodiments, the method also includes configuring the conductive base to be affixed at a surface location at an edge of a permanently shadowed region at a second end of the conductive base.

Additionally or alternatively, in this or other embodiments, the forming the second side of the tower with the panel includes forming the second side of the tower with an aluminum panel, copper panel, steel panel, conductive polymer panel, or conductive composite panel.

Additionally or alternatively, in this or other embodiments, the forming the second side of the tower with the panel includes forming the second side of the tower with the panel including a coolant channel configured for convective heat transfer from the panel or the attaching the conductive base includes attaching the conductive base including a second coolant channel configured for convective heat transfer from the conductive base.

DETAILED DESCRIPTION

As previously noted, the ability to perform power generation in space (e.g., on a lunar surface, on Mars) would reduce the need for energy storage and facilitate longer-term missions. A prior approach to power generation relies on solar panel arrays with photovoltaic modules that use photons radiated from the Sun to generate electricity via the photovoltaic effect. However, solar panel arrays suffer from inefficiency that results in the loss of much of the solar energy in the form of waste heat. Another existing technology that uses solar energy is solar thermoelectric generators (STEGs). A STEG is a solid state device that converts heat flux (i.e., a flow of energy due to a temperature difference) resulting from solar energy absorbed by one part of the STEG into electrical energy via a thermoelectric effect referred to as the Seebeck effect.

Power generation via solar panel arrays and STEGs has been combined in a hybrid system. Specifically, waste heat emanated by the solar panel array is harnessed by the STEG. That is, the conductive transfer of the waste heat through thermoelectric elements is used to generate electricity. Embodiments of the systems and methods detailed herein relate to thermoelectric power generation using radiant and conductive heat dissipation. Specifically, a hybrid system of a solar panel array and STEG is used and the conduction of the waste heat to a cold side of the system through thermoelectric elements is the source of electricity. According to the exemplary embodiments, this heat transfer and, thus, the electricity generation are encouraged by dissipating the transferred heat from the cold side via radiation and conduction. The radiant and conductive heat dissipation maintains the temperature differential required for a functioning STEG. The location and orientation of the hybrid system is controlled to enable effective radiative heat dissipation using deep space as a blackbody heat sink and conductive heat dissipation into a permanently shaded region (PSR).

FIG.1illustrates a thermoelectric power generation system100according to one or more embodiments. The system100includes a solar panel array110that represents a hot side of the thermoelectric generator and a panel120of the thermoelectric generator that may be a metal (e.g., aluminum, copper, steel) or a conductive polymer or conductive composite. The material of the panel120may be selected based on thermal properties. An insulator115is between the solar panel array110and panel120and includes a number of known thermoelectric elements125that contact the solar panel array110on one side and the panel120on the other to direct the flow of heat from the solar panel array110to the panel120. The thermoelectric elements125convert the thermal energy (i.e., waste heat) flowing from the solar panel array110to the panel120into electrical energy. The solar panel array110, insulator115, and panel120may be referred to together as a tower135.

The electrical energy produced by the thermoelectric elements125may be provided via a wire145to a load150. The load150will also receive electrical energy produced by photovoltaic modules of the solar panel array110, as indicated. The load150may be a habitat or equipment that requires electrical energy. While four thermoelectric elements125are shown for illustrative purposes, the number of thermoelectric elements125may be based on the size of the insulator115and/or on the power generation needs. The cross-sectional area and length of each thermoelectric element125, as well as the material from which it is fabricated, may also be selected based on the energy demands and the available space.

The thermoelectric power generation system100is shown with a gimbal130that facilitates control of the orientation of the tower135. The gimbal130allows the tower135to be oriented up or down and from side to side, according to the arrangement shown inFIG.1, based on a position of the sun, the source of solar radiation. That is, the gimbal130facilitates changing a position of the tower135in two dimensions that are perpendicular to each other. One of the dimensions is indicated inFIG.1and the other is indicated inFIG.2. A controller140may be used to implement orientation control of the tower135. The controller140may be collocated, as shown, or may be located away from the rest of the thermoelectric power generation system100such that control is remote via cables or wirelessly. The solar panel array110is oriented toward and to maximize exposure to solar radiation while keeping the panel120oriented toward the deep space, which serves as a blackbody radiative heat sink.

A portion of the solar radiation from the sun that is absorbed by the solar panel array110is not used for power generation by the photovoltaic modules due to inefficiency. As indicated inFIG.1, this waste heat is transferred through the tower135from the solar panel array110side to the panel120side as conductive heat flow C1due to the thermal gradient. The thermoelectric elements125produce electrical energy based on this conductive heat flow C1. Thus, the power generated by the thermoelectric elements125is proportional to the temperature difference between the solar panel array110side and the panel120side, since a higher temperature difference results in greater heat flow C1.

According to one or more embodiments, the thermoelectric power generation system100benefits from increased dissipation of heat from the panel120via conductive heat transfer, indicated as C2, in addition to radiative heat transfer, indicated as R. The dissipation of heat from the panel120maintains a temperature gradient between the solar panel array110and the panel120and encourages conductive heat flow C2and, thus, power generation by the thermoelectric elements125. The orientation of the tower135is controlled, based on the gimbal130and the controller140, to orient the solar panel array110toward the incoming solar radiation while keeping the panel120oriented toward the blackbody radiative sink that is deep space. This orientation facilitates radiative dissipation of the waste heat originating from the solar panel array110from the panel120.

A conductive base160of the thermoelectric power generation system100, which supports the tower135, is a metal (e.g., aluminum). As shown inFIG.1, the base160is physically coupled to the tower135. Specifically, the base160is attached to the panel120at one end and is affixed to the ground (e.g., planetary surface such as the lunar surface) at an opposite end. According to one or more embodiments, the location of the thermoelectric power generation system100and specifically the base160is selected to be at an edge of a PSR, as shown. Because of its location at the edge of the (cold) PSR, the base160promotes conductive heat flow, indicated as C2, from the panel120down the base160and into the ground. Thus, in addition to radiative dissipation of heat based on the orientation of the panel120toward deep space, the panel120also experiences conductive dissipation of heat based on the location of the base160near the PSR.

According to one or more alternative embodiments, convective heat flow may be used in addition to the radiative and conductive heat dissipation of the panel120. A coolant channel121is indicated within the panel120and a coolant channel161is indicated within the base160. The source of each coolant channel121,161may be at the habitat or near the base160, for example. The exemplary path shown for each coolant channel121,161is not intended to be limiting. According to one alternate embodiment, only the coolant channel121is used to additionally cool the panel120via convective heat transfer from the panel120to the coolant flowing within the coolant channel121. According to another alternate embodiment, only the coolant channel161is used to cool the base160via convective heat transfer to further encourage conductive heat transfer, indicated as C2, from the panel120to the base160. According to yet another alternate embodiment, both of the coolant channels121and161are used. In addition, the panel120may be painted white to maximize thermal emissivity.

FIG.2shows aspects of the thermoelectric power generation system100according to one or more embodiments. WhileFIG.1is a side view of the tower135, the perspective view inFIG.2shows only the solar panel array110of the tower135and the solar panels210. The dashed arc indicates the second (side-to-side) dimension in which the hinge130facilitates positioning of the tower135to orient the solar panels210to face the solar radiation.