Method and apparatus for producing hydrogen using solar energy
AssigneeNational Research Development Corporation
InventorGeorge Porter
Life of this patent
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Abstract
Apparatus suitable for use as a solar energy collector, the apparatus comprising a closed loop through which, in use, an aqueous solution can be circulated and be impinged upon by incident sunlight; means for circulating the aqueous solution around the closed loop; an inlet for introducing reactants into the closed loop; at least one unit in which the aqueous solution can be subjected to a chemical reaction, the said unit being interposed in the closed loop in a manner such that the said solution can flow through the unit; and an outlet for withdrawing products from the closed loop. The use of such apparatus to perform the photochemical oxidation of water to give oxygen and a reduced electron acceptor which acts as a store of energy is also described.
Claims26
A unidirectional continuous flow solar energy collector comprising a closed loop through which, in use, an aqueous solution can be circulated continuously in one direction only and be impinged upon by incident sunlight while circulating through the said loop;
- means for circulating the aqueous solution continuously in one direction through the closed loop;
- an inlet for introducing reactants into the closed loop;
- at least one station comprising a means for the liberation of hydrogen derived from the water of the aqeuous solution, the hydrogen being in gaseous or combined form, said station being interposed in the closed loop in a manner such that the aqueous solution can flow through the station;
- and an outlet for withdrawing products from the closed loop.
A method for the collection of solar energy by photo-oxidation of water and for the conversion of such energy into a chemical fuel, which method comprises:
- (i) forming an aqueous solution of an absorbing substance D, a reducing substance R and an oxidising substance Ox, the substances D R and Ox being chosen so that upon irradiation by sunlight dissociation and photo-oxidation of water takes place as a result of D absorbing light and the resultant excited state of D reacting with R, Ox and water to oxidise to R to R.sub.Ox and reduce Ox to Ox.sub.R ;
- (ii) causing the said aqueous solution to circulate in one direction around the closed loop of a unidirectional, continuous flow solar energy collection apparatus while irradiating the solution with incident sunlight to thereby cause said photo-oxidation of water;
- the said solar energy collection apparatus comprising a closed loop through which, in use, an aqueous solution is continuously circulated in one direction only and is impinged upon by incident sunlight while circulating the aqueous solution continuously in one direction around the closed loop, an inlet for introducing reactants into the closed loop, at least one first station comprising means for regenerating Ox from Ox.sub.R with liberation of hydrogen as chemical fuel, an optional at least one second station comprising means for regenerating R from R.sub.Ox with concomittant release of oxygen, the said first and second stations being interposed in the closed loop in a manner such that the said aqueous solution flows through the first and second stations, and an outlet for withdrawing products from the closed loop;
- (iii) at the said first station in the closed loop, regenerating Ox from Ox.sub.R with liberation of hydrogen as the chemical fuel;
- (iv) optionally at the said second station in the closed loop, regenerating R from R.sub.Ox with concomitant release of oxygen;
- and (v) introducing water into the closed loop to replace dissociated water.
Dependencies are inferred from the claim text.