Wood-based solar thermal devices, and methods for fabrication and use thereof

Abstract

Solar thermal devices are formed from a block of wood, where the natural cell lumens of the wood form an interconnected network that transports fluid or material therein. The block of wood can be modified to increase absorption of solar radiation. Combining the solar absorption effects with the natural transport network can be used for various applications. In some embodiments, heating of the modified block of wood by insolation can be used to evaporate a fluid, for example, evaporating water for extraction, distillation, or desalination. In other embodiments, heating of the modified block of wood by insolation can be used to change transport properties of a material to allow it to be transported in the interconnected network, for example, heating crude oil to adsorb the oil within the block of wood.

1 . A solar thermal device comprising:
 a natural wood block having:
 a first surface for receiving solar radiation thereon; 
 a second surface, opposite the first surface, for contacting fluid; 
 an internal fluidic transport network comprised of microstructures of natural wood between the first and second surfaces; and 
 a plurality of artificial holes extending from the first surface to the second surface; and 
   a solar absorption layer on at least the first surface of the natural wood block,   wherein the natural wood block pumps fluid from the second surface to the first surface by the internal fluidic transport network via capillary action and/or nano-cavitation effects, and   fluid from the internal fluidic transport network and/or from the first surface returns to the second surface via the artificial holes.   
     
     
         2 . The solar thermal device of  claim 1 , wherein each artificial hole has a diameter of 100 μm to 5 mm. 
     
     
         3 . The solar thermal device of  claim 1 , wherein the fluid contains salt, and the natural wood block is constructed such that a salinity in the internal fluidic transport network is higher than a salinity within the artificial holes during transport of the fluid between the first and second surfaces. 
     
     
         4 . The solar thermal device of  claim 1 , wherein
 the natural wood block has cellulose-based lumen extending along a tree growth direction that is substantially parallel to at least one of the first and second surfaces, and   the internal fluidic transport network comprises spirals or pits between adjacent lumen.   
     
     
         5 . The solar thermal device of  claim 1 , wherein
 the natural wood block has cellulose-based lumen extending along a tree growth direction that is at a non-zero angle with respect to at least one of the first and second surfaces, and   the internal fluidic transport network comprises the lumen.   
     
     
         6 . The solar thermal device of  claim 1 , wherein the solar absorption layer comprises:
 a carbonized portion of the natural wood block, or   a coating of at least one of nanoparticles, nanowires, graphene, graphene oxide, reduced graphene oxide, graphite, single walled carbon nanotubes, double walled carbon nanotubes, multiwalled carbon nanotubes, polyaniline, carbon black, amorphous carbon, hard carbon, and soft carbon.   
     
     
         7 . The solar thermal device of  claim 6 , wherein the nanoparticles comprise plasmonic metallic nanoparticles. 
     
     
         8 . The solar thermal device of  claim 1 , further comprising at least one of:
 a concentrator that focus insolation onto the first surface;   a collector that collects vapor emanating from the first surface; and   a condenser that condenses vapor from the first surface.   
     
     
         9 . A solar thermal device comprising:
 a natural wood block having:
 a first surface for receiving solar radiation thereon; 
 a second surface, opposite the first surface, for contacting fluid; and 
 an internal fluidic transport network comprised of microstructures of natural wood between the first and second surfaces; and 
   a solar absorption layer on at least the first surface of the natural wood block,   wherein the natural wood block has cellulose-based lumen extending along a tree growth direction that is substantially parallel to at least one of the first and second surfaces,   the internal fluidic transport network comprises spirals or pits between adjacent lumen, and   the natural wood block pumps fluid from the second surface to the first surface by the internal fluidic transport network via capillary action and/or nano-cavitation effects.   
     
     
         10 . The solar thermal device of  claim 9 , wherein the solar thermal device comprises at least one artificial hole extending from the first surface to the second surface and having a diameter of 100 μm to 5 mm. 
     
     
         11 . The solar thermal device of  claim 9 , wherein the solar absorption layer comprises:
 a carbonized portion of the natural wood block, or   a coating of at least one of nanoparticles, nanowires, graphene, graphene oxide, reduced graphene oxide, graphite, single walled carbon nanotubes, double walled carbon nanotubes, multiwalled carbon nanotubes, polyaniline, carbon black, amorphous carbon, hard carbon, and soft carbon.   
     
     
         12 . The solar thermal device of  claim 11 , wherein the nanoparticles comprise plasmonic metallic nanoparticles. 
     
     
         13 . The solar thermal device of  claim 9 , further comprising at least one of:
 a concentrator that focus insolation onto the first surface;   a collector that collects vapor emanating from the first surface; and   a condenser that condenses vapor from the first surface.   
     
     
         14 . A solar thermal device comprising:
 a carbonized block of natural wood having:
 a first surface for receiving solar radiation thereon; 
 a second surface, opposite the first surface, for contacting a material to be adsorbed; and 
 an internal fluidic transport network comprised of microstructures of the natural wood between the first and second surfaces; 
   wherein all internal and external surfaces of the carbonized block have been carbonized,   the carbonized block has a porosity greater than that of the natural wood, and   the carbonized block is constructed to adsorb said material into the internal fluidic transport network.   
     
     
         15 . The solar thermal device of  claim 14 , wherein said surfaces of the carbonized block are hydrophobic. 
     
     
         16 . The solar thermal device of  claim 14 , wherein
 the carbonized block has cellulose-based lumen extending along a tree growth direction that is at a non-zero angle with respect to at least one of the first and second surfaces, and   the internal fluidic transport network comprises the lumen.   
     
     
         17 . The solar thermal device of  claim 14 , wherein
 the carbonized block has cellulose-based lumen extending along a tree growth direction that is substantially parallel to at least one of the first and second surfaces, and   the internal fluidic transport network comprises spirals or pits between adjacent lumen.   
     
     
         18 . The solar thermal device of  claim 17 , wherein the carbonized block includes at least one artificial hole extending from the first surface to the second surface, each artificial hole having a diameter of 50 μm to 500 μm. 
     
     
         19 . The solar thermal device of  claim 14 , wherein the greater porosity includes pores introduced by at least one of:
 at least partial delignification of the natural wood prior to carbonization thereof; and   CO 2  activation during carbonization.   
     
     
         20 . The solar thermal device of  claim 14 , further comprising a pump that removes the adsorbed material from the from the carbonized block. 
     
     
         21 - 39 . (canceled)