Fresnel Solar Concentrator Mirror Control for Steam Temperature
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Solution Overview
Problem
Fresnel-type concentrating solar power plants with direct steam generation face challenges in maintaining the steam temperature at the nominal operating temperature due to performance degradation and solar flux variations, leading to inefficiencies and energy loss when trying to compensate with oversizing or defocusing mirrors.
Innovation Solution
A Fresnel-type solar power plant design with at least two receivers, one for vaporization and one for superheating, where the movement and focusing of mirrors are controlled to rebalance energy distribution between the receivers, optimizing the use of mirror surface area and maintaining steam temperature by redirecting energy from one receiver to another as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the solar field is sized to reach the nominal temperature, pressure and steam flow setpoint, then the nominal operating parameters are achieved, but the steam temperature cannot be maintained when solar flux varies or receiver performance degrades
Solution Approach 1:
The patent applies dynamics by making the mirror focusing adjustable rather than fixed. The system can dynamically change the focal length and mirror orientation to redirect solar flux between the vaporization section and superheating section, allowing real-time adaptation to maintain steam temperature despite varying solar conditions or receiver degradation.
Solution Approach 2:
The invention changes the optical parameters of the solar field by adjusting mirror focal lengths and orientations. This allows the system to modify the distribution of solar energy between different receiver sections, enabling temperature control through parameter adjustment rather than fixed design conditions.
2Temperature
If the vaporization and superheating sections are oversized to compensate for performance degradation, then temperature control is improved, but the cost increases and energy is lost due to defocusing mirrors
Solution Approach 1:
Instead of static oversizing, the system uses dynamic mirror adjustment to optimize energy distribution. Mirrors can be actively focused on either the vaporization or superheating section as needed, preventing energy loss from defocusing while maintaining temperature control through real-time optimization of the solar field configuration.
3Temperature
If mirrors are defocused to compensate for receiver performance imbalance, then energy distribution can be adjusted, but the utilization rate of mirror surface area decreases
Solution Approach 1:
The system replaces static defocusing with dynamic focusing. Mirrors maintain optimal focus on their target receiver section while the focal length and orientation are adjusted to redirect energy flow. This dynamic approach preserves mirror surface utilization by ensuring all mirrors remain actively focused, unlike static defocusing which wastes optical capacity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for optimized use of mirror surface area, compensates for performance imbalances, and accelerates the start-up phase by ensuring steam is produced at the desired temperature, reducing energy loss and maintaining efficiency.
Implementation Method 1
flat mirrors which reflect the light rays on the receiver, which has the effect of heating the fluid
Implementation Method 2
concentrating solar power plant
Implementation Method 3
the fluid leaving the receiver is in the form of superheated steam or saturated steam
Implementation Method 4
At the inlet of the receiver, the fluid is in liquid form, it vaporizes while circulating in the duct(s)
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3
AI summary
Solar power station of the Fresnel type comprising a vaporizing receiver (2) and a superheating receiver (4) arranged in parallel, and mirrors (8.1, 8.2) comprising first mirrors (8.1) focused on the vaporizing receiver (2) during nominal operation and the second mirrors (8.2) being focused on the superheating receiver (4) in nominal operation, mirror movement means, in which power station the superheating receiver (4) is supplied with fluid in the form of steam by the vaporizing receiver (2), said power station also comprising means for controlling the movement means, and means for measuring at least one operating parameter of the power station. The control means activate the movement means as a function of at least one operating parameter of the power station so that at least one mirror (8.1, 8.2) is focused onto a different receiver (2, 4) from the receiver on which it is focused in nominal operation.