Solar cooking pot

Abstract

A solar cooker in the form of a pot with double-walled body and lid configured to collectively constitute a near-hermetic thermal enclosure including a closed, solar radiation-absorbing and heat-retaining vessel surrounded by a vacuum insulation shield encased in a transparent peripheral jacket. The device intercepts solar energy omnidirectionally, and collects and retains it with sufficient efficiency to pasteurize water and cook food without resorting to outside reflectors, refractors, conductors, or insulators, thereby escaping from the dual requirements of solar concentration and orientation that universally govern the construction and operation of existing solar cookers. Freedom from these restrictions enables designs that are inexpensive, simple, compact, lightweight, sturdy, accessible, and applicable in varied geographic, climatic, economic, social, and culinary contexts.

1 . A solar cooking pot comprising:
 a body and a lid,   the body comprising a first double wall defining a cavity, said wall comprising a first inner wall, a first outer wall, a first space therebetween, and a first closure extending between said inner and outer walls and enclosing said space, said inner wall having a solar selective outer surface with high absorptivity and low emissivity, said outer wall being transparent, and said space being evacuated;   the lid comprising a second double wall defining an inner and an outer side, said second double wall comprising a second inner wall, a second outer wall, a second space therebetween, and a second closure extending between said second inner and outer walls and enclosing said second space, said second inner wall having a solar selective outer surface with high absorptivity and low emissivity, said second outer wall being transparent, and said second space being evacuated;   said first and second closures being configured such that when said body and said lid are mated through said closures, said body and said lid are positively engaged, said first and second inner walls cooperatively constitute a substantially closed vessel with a solar selective outer surface, said first and second spaces cooperatively constitute a substantially closed vacuum insulation shield surrounding said vessel, said first and second outer walls cooperatively constitute a substantially closed transparent jacket surrounding said shield, and said body and said lid cooperatively constitute a substantially hermetic thermal enclosure wherein solar energy is absorbed and heat is retained;   whereby said solar cooking pot is enabled to function as a solar cooker when exposed to the sun, and as a heat retention cooker in the absence of insolation.   
   
   
       2 . The device of  claim 1  wherein said first and second closures are integral projections of said first and second outer walls respectively. 
   
   
       3 . The device of  claim 1  wherein said first and second closures are composed of a material with high thermal resistance and low thermal conductance. 
   
   
       4 . The device of  claim 1  wherein said first and second closures are configured with nonlinear complementary cross-sectional profiles with a centripetally downward slope, said first inner wall extends toward said lid beyond the extent of said first closure by a first selected distance, said second inner wall extends toward said body short of the extent of said second closure by a second selected distance, said first selected distance being greater than said second selected distance; in a configuration such that when said body and said lid are mated, said first and second inner walls come into intimate contact, said first and second closures are separated by a clearance gap, the thickness of said gap being equal to the difference between said first and second selected distances, no visual line of sight exists between any part of said inner walls and the external environment, and any solid or liquid material present in said gap preferentially drains to the outside. 
   
   
       5 . The device of  claim 1  wherein said first and second outer walls are composed of polycarbonate. 
   
   
       6 . The device of  claim 1  wherein said first and second inner walls each comprise an inner layer, a core layer, and an outer layer, said inner layer being composed of a radiant non-stick plating or coating with high emissivity, said core layer being composed of a metal, and said outer layer being composed of a solar selective plating or coating. 
   
   
       7 . The device of  claim 1  wherein said first inner wall is provided with a thermometer permanently mounted on its outer surface, said thermometer being wholly contained within said first space. 
   
   
       8 . The device of  claim 7  wherein said thermometer is provided with indicia for the temperatures of water pasteurization, water boiling, and safe operating range. 
   
   
       9 . The device of  claim 7  wherein said thermometer is provided with an indicator and a display that glow in the dark. 
   
   
       10 . The device of  claim 1  wherein said first and second outer walls are provided with coatings or inclusions that glow in the dark. 
   
   
       11 . The device of  claim 1  wherein said body and lid each have a density less than the density of water. 
   
   
       12 . The device of  claim 1  wherein said second outer wall is provided with a multiplicity of circular depressions of a size suitable for accepting fingertips. 
   
   
       13 . The device of  claim 1  wherein said first and second outer walls are each provided with one or more groove means adapted for securing belts, or one or more loop means adapted for securing lanyards. 
   
   
       14 . The device of  claim 1  including a packaging system adaptable for use as an accessory solar performance booster. 
   
   
       15 . A solar cooking pot built from four separate parts formed from plastic sheet material, comprising a two-part body and a two-part lid,
 said body being shaped as a circular container and comprising a body liner and a body shell enveloping said body liner and leaving a body space therebetween, said body liner being solar absorbent, said body shell being transparent, said body liner being provided with an integral body liner lip, said body shell being provided with an integral body shell lip, said body liner lip and body shell lip being sealed together to form a body closure enclosing said body space, and said body space being evacuated;   said lid being shaped as a circular container or disk and comprising a lid liner and a lid shell separated from said lid liner by a lid space therebetween, said lid liner being solar absorbent, said lid shell being transparent, said lid liner being provided with an integral lid liner lip, said lid shell being provided with an integral lid shell lip, said lid liner lip and lid shell lip being sealed together to form a lid closure enclosing said lid space, and said lid space being evacuated;   said body and lid closures being configured such that when said body and lid are mated, said body and lid are positively engaged, said body and lid liners cooperatively constitute a substantially closed vessel with a solar absorbent outer surface, said body and lid spaces cooperatively constitute a substantially closed vacuum insulation shield surrounding said vessel, said body and lid shells cooperatively constitute a substantially closed transparent jacket surrounding said shield, and said body and said lid cooperatively constitute a substantially hermetic thermal enclosure wherein solar energy is absorbed and heat is retained;   said liners and shells being configured to facilitate fabrication by die cutting, vacuum forming, and heat sealing;   whereby said solar cooking pot is manufacturable with inexpensive materials and accessible methods.   
   
   
       16 . The device of  claim 15  wherein said body liner is composed of a black plastic sheet material. 
   
   
       17 . The device of  claim 15  wherein said body liner is coated on its outer surface with a solar selective coating. 
   
   
       18 . The device of  claim 15  wherein said body and lid shells collectively include one or more integral reinforcing projections respectively engaging said body and lid liners. 
   
   
       19 . The device of  claim 15  wherein said body and lid spaces collectively include one or more reinforcing inserts. 
   
   
       20 . The device of  claim 15  including a packaging adaptable for use as an accessory solar performance booster.