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This article presents an analysis of the optical design characteristics of a stationary reflecting/tracking absorber solar energy collector. This type of collector consists of a segment of a spherical mirror placed in a stationary position facing the sun, but having a linear absorber that can track the image of the sun by a simple pivoting motion about the center of curvature of the reflector. The optical characteristics of this system and the axial variation of its concentration ratio are developed to provide information for the engineering design and sizing of this type of solar energy collector system.

Transient forced convection heat transfer coefficients for both subcritical and supercritical helium in a rectangular flow channel heated on one side were measured during the application of a step in heat flux. Zero flow data were also obtained. The heater surface which served simultaneously as a thermometer was a fast response carbon film. Operating conditions covered the following range: Pressure, 1.0 × 105 Pa (1 bar) to 1.0 × 106 Pa (10 bar); Temperature, 4 K–10 K; Heat Flux, 0.1 W/cm2−10 W/cm2; Reynolds number, 0–8 × 105. The experimental data and a predictive correlation are presented.

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