Hybrid solar/combustion powered receiver

Claim 1

An improved hybrid solar/combustion powered receiver of the type having an insulated housing with a front end and a rear end, a heat exchanger positioned adjacent the rear housing end for extracting heat energy out of the receiver, the insulated housing surrounding the heat exchanger and forming a receiver cavity, the housing also including an aperture having an aperture axis, said aperture located in the front housing end for admitting solar radiation to the cavity to impinge upon the heat exchanger, and a plurality of gas burners to provide combustion gases within the receiver, the improvement comprising: (a) the heat exchanger being formed from a plurality of individual adjacent heater pipes arranged in a generally conical array each of the heater pipes being spaced from an adjacent heater pipe, the axis of said conical array being in line with the aperture axis, the conical array arranged such that the solar radiation impinges on a surface of each of the heater pipes; (b) the gas burners being positioned circumferentially about the axis of said conical heater pipe array for inducing a flow of combustion gases within the receiver cavity along substantially all of the surface of each of the apart heater pipes of said conical array upon which the solar radiation impinges, said gases also passing between the heater pipes, the burners being positioned to cause the hottest part of the burner flame to be located in front of said heater pipe array relative to the aperture, namely between said heater pipe array and the aperture, the combustion gas flow pattern being from the burners, between said heater pipes, and then to a back of said conical array adjacent the rear of the housing within the receiver cavity; (c) the portion of the rear of the housing within the receiver cavity adjacent said conical array being positioned closely adjacent said array to form a combustion gas flow channel for increasing the velocity of the combustion gas flowing between the heater pipes relative to the combustion gas velocity in the other parts of the combustion gas flow pattern; and (d) means for preventing the escape of combustion gases through the aperture during combustion powered operation to reduce the resultant thermal energy losses through the aperture, wherein the receiver also is of the type having a preheater for preheating combustion air using heat transferred from the exhaust gases during combustion powered operation, the preheater having a combustion air flow path connecting a preheater air inlet with the receiver cavity and an exhaust gas flow path connecting the cavity with a preheater exhaust exit, the improvement further including combustion air manifold means for interconnecting the preheater air inlet and a combustion air source, said manifold means including a plurality of manifold elements positioned on an outside surface of the housing for intercepting and recovering thermal energy conducted through the housing wall during combustion powered operation, including a portion of the housing wall adjacent the aperture, and wherein said means for preventing includes an aperture window, and wherein at least one of said manifold elements has a manifold inlet positioned to draw air from the vicinity of a surface of said window, for cooling said window outside of the receiver cavity.