Your Answer : (Not Answered)

Correct Answer : C

The major advantage is operation at higher temperature.

A concentrating collector focuses sunlight from a large aperture onto a small absorber. Heat losses scale with the absorber area, so they are small relative to the energy collected, and the working fluid can reach hundreds of degrees, enough for process steam or power generation. Flat plate collectors are limited to roughly 100 °C.

Concentrators can use only direct beam radiation, not diffuse, and need tracking, which raises cost rather than lowering it. For the same output the aperture area is set by the solar energy needed, so it is the absorber, not the aperture, that becomes smaller.

Your Answer : (Not Answered)

Correct Answer : A

The angle is the declination.

Solar declination is the angle between the line joining the centres of the Sun and the Earth and its projection on the Earth's equatorial plane. Because the Earth's axis is tilted by about 23.45°, it varies through the year from +23.45° at the June solstice to -23.45° at the December solstice, and is zero at the equinoxes.

Latitude locates a place on Earth, not the Sun. The azimuth angle is measured in the horizontal plane, and the zenith angle between the Sun's direction and the local vertical.

Your Answer : (Not Answered)

Correct Answer : A

The complement of the solar altitude angle is the zenith angle.

The solar altitude angle is measured up from the horizontal to the line to the sun. The zenith angle is measured down from the vertical (the zenith) to the same line. Horizontal and vertical are at right angles, so the two angles add up to 90°: zenith angle = 90° − altitude angle.

The azimuth angle measures the sun’s direction in the horizontal plane, from north or south. The hour angle measures the time from solar noon, at 15° per hour. The profile angle is the sun’s altitude projected onto a vertical plane normal to a surface, used in shading design. None of them is defined as 90° minus the altitude.