Wind loss prevention for open cavity solar receivers

DETAILED DESCRIPTION Referring now to FIG.
1, an open cavity receiver 10 which operates at or close to ambient pressure is illustrated as having a cavity 12, an aperture 14, a heat exchanger 16 in the form of a ceramic honeycomb in the cavity and a terminal concentrator 18 or similar structure which, in general, has a frusto-conical shape and is located symmetrically about aperture 14 for redirecting stray radiation from a mirror field 20 into the receiver cavity.
It will be appreciated that not all solar receivers need have terminal concentrators and that the subject systems for airflow deflection may be located at the receiver aperture if no terminal concentrator is used.
Note: rays from the sun generally indicated by reference characters 22 are redirected by the mirrors of the mirror field as illustrated by rays 24 and are focused on heat exchanger 16.
The mirrors track the movement of the sun during the day so as to maintain the sun focused onto the heat exchanger.
In one embodiment receiver 10 may be mounted in a central receiver tower 26 and may have an outlet line 28 connected to the inlet of a heat storage unit 30.
The outlet of storage unit 30 is connected to a conventional blower type pumping system 32 which draws air through the storage unit and returns it over line 34 to the front end of the receiver cavity 12.
In operation, solar energy impinging on the heat exchanger causes the temperature of the heat exchanger to rise.
Energy from the heat exchanger is then transferred to air from the illuminated end of the receiver.
This air passes through the heat exchanger and out through line 28 to storage unit 30.
When storage unit 30 is charged up, for instance, to a temperature of 2000.
degree.
F.
, it is switched to the position indicated by storage unit 40 by conventional valve means.
Storage unit 40 is discharged over line 42 to a conventional Brayton cycle engine 44 which is mechanically coupled to an electric generator 48.
The outlet gas from the turbine section of the Brayton cycle engine is returned over line 50 to a pumping station 52 which pressurizes storage unit 40 via line 54 during the discharge of the storage unit