Solar radiant heating of gas-particle mixtures. FY 1984 summary report [report]

A. Hunt, J. Ayer, P. Hull, R. McLaughlin, F. Miller, J. Noring, R. Russo, W. Yuen
1986 unpublished
The technology that underlies the current state of solar thermal conversion is a product of more than a century of experience with fossil fuel combustion. It is a relatively mature technology, but has biased contemporary thinking about heat transfer mechanisms towards convection and conduction. Concentrated sunlight, however, is an intense source of pure radiant energy, originating from a 5800 0 K blackbody, that has quite .different characteristics from the less intense radiation emitted by
more » ... sil fuel combustion. It is therefore appropriate to. develop a solar energy conversion method that fully takes advantage of the unique characteristics of solar radiation. The use of small particles, dispersed in a gas, ~o directly absorb concentrated sotar radiation, is just that method. In absorbing materials, radiation is converted to heat within distances comparable to the wavelength of light. Therefore, absorbers in the form of dispersed micron-sized particles can collect the solar radiation efficiently. Moreover, small particles present a very large surface area per unit mass; heat and mass transfer, and surface chemical activity, are greatly enhanced. This report describes the FY 1984 research program at Lawrence Berkeley Laboratory which investigated a unique solar receiver embodying the above principle. In this receiver, a gas-particle mixture directly absorbs concentrated sunlight to drive an endothermic chemical reaction for the production of a useful fuel or chemical. We call this solar receiver STARR, an acronym for Solar Thermally Activated Radiant Reactor. The objective of the work was to understand the optical, thermodynamic, and chemical processes in solar heated particle suspensions through a balanced program of analytical and experimental investigations. This work was built upon the effort in previous years of using gaS-particle mixtures to heat a gas, which culminated in the successful test of the concept in 1982.
doi:10.2172/5188817 fatcat:bkdzmu23pngifhecaoc6424a2y