Why tracking matters for concentrated solar
Solar tracking keeps mirrors or lenses aimed at the sun as it moves across the sky, which is essential for maintaining concentrated sunlight on a small receiver. Without tracking, the focal point would drift, significantly reducing the system’s ability to concentrate energy and lowering the operating temperature.
Tracking benefits include:
- Higher energy capture: Following the sun increases the hours that collectors operate at optimal angles, raising daily energy yield.
- Consistent high temperatures: For CSP, stable temperature at the receiver improves thermal-to-electric conversion efficiency and supports storage charging.
- Smaller optics: Accurate tracking lets designers use smaller reflectors and receivers for the same energy capture, saving materials and cost.
Types of tracking systems:
- Single-axis tracking: Rotates collectors around one axis (usually east–west) to follow the sun’s daily path. It offers a good balance of performance and simplicity and is common in trough and linear Fresnel systems.
- Dual-axis tracking: Follows both daily and seasonal sun movement, keeping the reflector pointed directly at the sun. Dual-axis is used for dishes and some heliostats and yields the highest concentration and efficiency.
- Fixed-tilt: No tracking; simplest and cheapest but unsuitable for high-concentration CSP because it cannot maintain focus.
Tracking systems add complexity, cost, and maintenance, with motors, gearboxes, control electronics, and position sensors. However, for CSP applications that depend on focused sunlight, tracking is not optional: it substantially increases capacity factors and makes thermal storage practical by maintaining steady input temperatures.
In summary, tracking enables concentrators to maintain precise optical alignment with the sun, boosting energy capture, operating temperature, and overall plant performance, while requiring additional engineering and upkeep.