NOVELTY - Solar thermochemical processing system comprises: a first unit operation for receiving concentrated solar energy, using heat from the solar energy to drive the first unit operation, where the first unit operation also receives a first set of reactants and produces a first set of products; a second unit operation for receiving the first set of products from the first unit operation and for producing a second set of products; and a third unit operation for receiving heat from the second unit operation to produce a portion of the first set of reactants.    USE - The solar thermochemical processing system is useful for: storing solar energy which is useful for generating power; and for producing fuels (all claimed) including transportation fuels (e.g. diesel fuel and jet fuel).    ADVANTAGE - The solar thermochemical processing system: has high solar-to-chemical energy conversion efficiency; and produces electricity at higher capacity factors and reduces costs compared to other solar energy systems.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a method (M1) of producing a liquid hydrocarbon product comprising: sending a first set of reactants into a first unit operation to produce a first set of products; sending the first set of products to a second unit operation to produce a second set of products; heating a third unit operation using heat from the second unit operation to produce a portion of the first set of reactants, where the second set of products is further reacted to produce the liquid hydrocarbon product; and achieving carbon utilization in fuel production above 85%;    (2) a method (M2) of providing temperature control to a solar thermochemical receiver comprising: providing a solar thermochemical receiver including a first material, where the first material has an inlet and at least one outlet; providing many flow mechanisms for coupling the inlet to the outlet separately; and adjusting the flow mechanisms to control the proportion of fluid flowing through the inlet and the outlet in response to conditions within the receiver;    (3) a method (M3) of storing solar energy comprising: (a1) preheating reactants and then directing the reactants into a first endothermic reactor to produce a first set of products, where the first endothermic reactor receives concentrated solar energy as a heat source; (b1) cooling the first set of products and then further reacting the first set of products in a first exothermic reactor to produce a second set of products, where the heat of reaction from the exothermic reactor is used to produce a portion of the first set of reactants; and (c1) separating the second set of products to enable fuel to be stored;    (4) a method (M4) of power generation comprising: steps (a1) and (b1) as above per se; and separating the second set of products to provide heat for at least one of a heat engine or a fuel cell;    (5) a method (M5) of providing a solar energy augment to the chemical energy content of a reactant stream, comprising: heating a solar reforming reactor from a solar concentrator; preheating reactants in a heat exchanger before entering the reactor; and reacting the reactants in the presence of a catalyst in the reactor to generate a product stream at a solar-to-chemical energy conversion efficiency greater than 60%, where the product stream includes syngas and the syngas is reacted in a chemical reactor to produce fuel;    (6) a solar thermochemical receiver for receiving heat and performing reactions comprising: a solar receiving front plate (810); a back plate (820) with support ribs and an entrance port; a manifold; and a flow channel with a size dimension of 100 mu to 1 cm, where a reactant flow enters near the center of the back plate and splits into multiple flow paths, and the reactant flows toward the periphery of the receiver through a catalyst and exits as a product through the manifold, the manifold recollects the product to exit away from where the reactants entered the receiver, and the receiver has a solar-to-chemical energy conversion efficiency of at least 60%;    (7) a tiled receiver reactor (800) for receiving heat and performing reactions comprising: the solar receiving front plate; and a back plate having individual tile sections, where the tile sections include an inlet (830), at least one outlet (840), and catalyst channels, and the length of at least one flow channel is decreased, to make the inlet in closer proximity to the outlets;    (8) a counter radial flow reactor for receiving heat and performing reactions comprising: outward flowing channels that enter the center of the reactor and flow in a radial direction towards outlet at the periphery of the reactor; and inward flowing channels, adjacent to the outward flowing channels, that enter at the periphery and exit toward the center of reactor;    (9) a solar gas-to-liquids process (P1) comprising: preheating a fluid stream including methane and water in a heat exchanger; reacting the fluid stream in a solar thermochemical reactor to generate a product stream at a solar-to-chemical energy conversion efficiency of at least 60%, where the product stream includes syngas; cooling the product stream in the heat exchanger; and reacting the syngas in a hydrocarbon synthesis reactor that produces fuel;    (10) a solar gas-to-liquids-and-electricity process (P2) comprising: preheating reactants with solar energy from a solar concentrator and then directing the reactants into a first endothermic reactor to produce a first set of products; step (b1) as above per se; and separating the second set of products to produce a third set of products that include a liquid hydrocarbon fuel and a fourth set of products that are used for power generation;    (11) a receiver (R1) comprising: channel walls defining a flow channel; and a flow control device, where the device includes an orifice cover partially blocking an outlet orifice, and the device is coupled to the channel walls; and    (12) a receiver (R2) comprising: a flow channel having an inlet and an outlet; an insert coupled to the outlet, where the insert has a lower or higher thermal expansion coefficient compared to the receiver; and a pin to constrain movement of the insert.    DESCRIPTION OF DRAWING(S) - The figure shows a front view of a tiled receiver-reactor.    Tiled receiver-reactor (800)    Front plate (810)    Back plate (820)    Inlet (830)    Outlet (840)