System and method for generating steam using a solar power source in conjunction with a geothermal power source
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Solution Overview
Problem
Conventional solar power systems using synthetic heat transfer fluids face issues with low energy density, flammability, and efficiency losses due to two-phase water/steam flow, leading to higher costs and safety concerns, while direct steam generation systems are inefficient and sensitive to solar flux and atmospheric conditions.
Innovation Solution
A pressurized solar power system that uses a closed loop of pressurized pipes to heat water above its boiling point, eliminating two-phase flow instability and leveraging water's superior heat transfer capabilities, with a control system to manage variable solar energy input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If synthetic heat transfer fluid is used in conventional CSP systems, then the system can operate with unpressurized pipes and simpler design, but the energy density is low (2100 J/kg°C vs 4200 J/kg°C for water) requiring larger and more costly heat transfer components
Solution Approach 1:
The patent changes the physical state parameter of water from atmospheric pressure to high pressure (e.g., 150-300 atm), which raises the boiling point from 100°C to above 370°C. This parameter change allows water to remain in liquid phase at high temperatures, achieving superior energy density (4200 J/kg°C) compared to synthetic fluids, thereby reducing the size of heat transfer components while maintaining safe operation without flammability risks
Solution Approach 2:
The patent replaces expensive synthetic heat transfer fluids (like Therminol®) with water, which is inexpensive and non-flammable. Although water has a lower boiling point at atmospheric pressure, the patent overcomes this by using high pressure to maintain liquid phase, achieving both cost reduction and improved energy density without the safety hazards of synthetic fluids
2Use of energy by moving object
If direct steam generation is used, then water's superior heat transfer capabilities are utilized, but two-phase flow instability (Ledinegg Instability) occurs creating boiling fronts that reduce efficiency
Solution Approach 1:
The patent changes the pressure parameter to maintain water in single-phase liquid state at high temperatures (above 370°C) by operating at high pressure (150-300 atm). This eliminates the two-phase flow instability and boiling front phenomena that occur in direct steam generation systems, allowing water to carry thermal energy efficiently while remaining in stable liquid phase throughout the heat transfer process
Solution Approach 2:
The patent segments the heat transfer process into two distinct phases: (1) water circulation and heating in pressurized solar collectors where water absorbs solar energy and reaches high temperatures while remaining liquid, and (2) steam generation in a separate heat exchanger where the heated water converts to steam to drive the turbine. This segmentation allows optimization of each phase independently, maintaining stable liquid flow in collectors and efficient steam generation in the heat exchanger
3Loss of energy
If synthetic heat transfer fluid is used, then the system can transfer thermal energy from solar collectors to heat exchanger, but the fluid is flammable creating safety risks and requiring careful handling to prevent overheating
Solution Approach 1:
The patent replaces flammable synthetic heat transfer fluids with water, which is non-flammable and safe. By operating at high pressure to raise the boiling point above 370°C, water achieves superior thermal energy transfer capability (4200 J/kg°C) without any fire hazard, eliminating the need for complex safety systems and careful handling procedures required for synthetic fluids
Solution Approach 2:
The patent creates an inert environment by using water under high pressure, which cannot combust or support combustion. The high-pressure liquid water system eliminates oxygen contact and combustion risks, providing an inherently safe heat transfer medium that transfers thermal energy efficiently without flammability concerns
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 achieves higher energy carrying capacity, reduces costs, and mitigates safety risks by using pressurized water, enhancing efficiency and allowing for smaller solar collectors, while the control system ensures efficient energy utilization and stability.
Implementation Method 1
CSP utilizes solar collectors comprising large mirrors, mirror arrays, or lenses, which concentrate solar energy upon a typically unpressurized pipe or tube that contains a heat transfer fluid
Implementation Method 2
A pressurized solar power system that uses a closed loop of pressurized pipes to heat water above its boiling point, eliminating two-phase flow instability
Implementation Method 3
One or more pumps are situated along the pipe to pump the fluid through the solar collectors and towards a boiler with a heat exchanger coil. At the heat exchanger coil, the transfer fluid is used to heat water in the boiler to produce steam
Implementation Method 4
The steam is then used for powering a steam driven engine that turns a generator to produce electricity
Data Source
AI summary
Systems and methods for generating electrical power using a solar power system that comprises a pressurized closed loop pipe containing a transfer liquid extending between a solar collector and a heat exchanger. The transfer liquid is heated by the solar collector and gives up its thermal energy at the heat exchange to produce steam. The system also includes a source of geothermal energy and a source of natural gas. The geothermal energy in the form of heat separates the natural gas from the ground water in a separation tank. At the resulting heated ground water from the separation tank is connected to the heat exchanger to supplement thermal energy from the solar collector.