Method for generating steam and electricity with solar power
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Solution Overview
Problem
Existing parabolic trough solar collectors face inconsistent heating due to fluctuations in irradiation and low efficiency, leading to suboptimal steam generation.
Innovation Solution
A two-pipe heat exchanger system with a helical pipe for water circulation and a sand-filled pipe for heat storage, controlled by a solenoid valve, which operates in two modes to generate steam during high irradiance and release steam during low irradiance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-pipe heat exchanger system is used, then the device complexity is reduced, but the steam generation consistency deteriorates under varying irradiation conditions
Solution Approach 1:
The heat exchanger system is divided into two separate pipes: a first pipe for receiving and heating water to generate steam during high irradiance, and a second pipe for receiving cooler water and generating steam during low irradiance. This segmentation allows the system to maintain consistent steam generation across varying solar conditions by switching between pipes based on thermal state.
2Adaptability or versatility
If solar radiation intensity fluctuates, then the adaptability to environmental conditions is improved, but the steam generation efficiency deteriorates
Solution Approach 1:
The system dynamically switches between the first and second pipes based on real-time irradiance conditions and thermal state. During high irradiance, the first pipe generates steam efficiently; during low irradiance, the second pipe uses stored thermal energy to maintain steam generation. This dynamic adaptation preserves productivity across varying environmental conditions.
Solution Approach 2:
The first pipe pre-heats water and generates steam during periods of high solar irradiance, storing thermal energy in the surrounding sand medium. This preliminary action ensures that when irradiance drops, the second pipe can immediately utilize the stored thermal energy to maintain steam generation without interruption.
3Ease of operation
If water is continuously circulated through a single pipe, then the ease of operation is improved, but the temperature control precision deteriorates
Solution Approach 1:
The system employs periodic switching between the first and second pipes based on thermal thresholds. The first pipe operates during high irradiance to heat water and generate steam, while the second pipe operates during low irradiance using stored thermal energy. This periodic operation maintains precise temperature control for steam generation while keeping the control system relatively simple.
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
The system ensures consistent steam production by leveraging solar radiation for efficient steam generation during varying irradiation conditions, enhancing the overall efficiency and reliability of solar power plants.
Implementation Method 1
focusing solar radiation upon the absorber tube and heating water in the helical pipe
Implementation Method 2
converting the water in the helical pipe to steam by focusing solar radiation upon the absorber tube
Implementation Method 3
heating sand in a sand filled pipe surrounded by the helical pipe
Implementation Method 4
A solenoid valve is connected between the helical pipe and the inner pipe. The solenoid valve is configured to block the water from entering the inner pipe when the solenoid valve is closed and release the water to the inner pipe when the solenoid valve is opened.
Data Source
AI summary
An absorber tube for a parabolic trough solar power plant is described. The absorber tube includes a glass pipe that extends from a first end to a second end of the parabolic trough. A helical pipe is enclosed within the glass pipe. The helical pipe is configured to hold water. A sand filled pipe is surrounded by the helical pipe. The absorber tube further includes an inner pipe, centered within the sand filled pipe and the inner pipe extends from the first end to the second end of the parabolic trough along a central axis of the glass pipe. A solenoid valve is connected between the helical pipe and the inner pipe. The solenoid valve is configured to block the water from entering the inner pipe during periods of high solar irradiance and release the water to the inner pipe during periods of low solar irradiance.