PV Array Thermal Management for Solar Hydrogen Efficiency
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Solution Overview
Problem
Solar hydrogen generation by photovoltaic-electrolyzer systems faces low efficiencies (2-6%) and high costs (> $11/kg H2) due to inefficiencies in converting solar irradiance to electrical energy and heat management, leading to suboptimal operating temperatures for both PV modules and electrolyzers.
Innovation Solution
A thermal management system that transfers heat from the PV array to the electrolyzer using a circulating fluid, maintaining the PV array at a lower temperature to optimize efficiency and the electrolyzer at a higher temperature to enhance hydrogen production, leveraging the opposite temperature dependencies of PV electricity generation and water electrolysis processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If PV modules operate at higher temperatures due to solar irradiance absorption, then the electrical energy conversion efficiency decreases, but the thermal energy available for heating the electrolyzer increases
Solution Approach 1:
The patent converts the harmful thermal energy (heat) that reduces PV electrical efficiency into a beneficial resource by transferring it to the electrolyzer. The heat exchanger captures waste heat from PV module cooling and uses it to preheat the electrolyzer inlet water, transforming an energy loss into a useful heating function that improves overall system efficiency.
Solution Approach 2:
The patent introduces a heat exchanger as an intermediary device between the PV modules and the electrolyzer. This mediator transfers thermal energy from the PV cooling fluid to the electrolyzer inlet water, enabling thermal coupling of the two subsystems and optimizing both electrical and thermal energy utilization.
2Productivity
If the electrolyzer operates at higher temperatures, then the hydrogen production efficiency increases, but additional thermal management complexity is required
Solution Approach 1:
The patent merges the PV cooling system with the electrolyzer heating system into a single integrated thermal management architecture. The heat exchanger combines these two functions, allowing the PV array cooling fluid to simultaneously cool the PV modules and heat the electrolyzer inlet water, reducing the need for separate thermal management systems.
Solution Approach 2:
The circulating fluid system serves multiple functions: it cools the PV modules to maintain electrical efficiency, heats the electrolyzer inlet water to improve hydrogen production, and can provide thermal energy storage capability. This multi-functional approach reduces overall system complexity compared to separate dedicated cooling and heating systems.
3Productivity
If thermal energy from PV modules is utilized to heat the electrolyzer, then the overall solar to hydrogen efficiency increases, but the PV module temperature control becomes more challenging
Solution Approach 1:
The patent implements temperature sensors and control logic that continuously monitor PV module temperature and electrolyzer inlet water temperature. The system adjusts the heat exchanger operation and fluid flow rates based on feedback from these sensors, automatically optimizing thermal energy transfer while maintaining PV modules within their optimal electrical performance temperature range.
Solution Approach 2:
The patent employs dynamic control of the thermal management system, adjusting heat exchanger effectiveness and fluid flow rates in real-time based on operating conditions. The system can modulate between maximizing electrical output (prioritizing PV cooling) and maximizing hydrogen production (prioritizing electrolyzer heating) depending on ambient temperature, solar irradiance, and electrolyzer operational requirements.
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 increases the overall solar to hydrogen efficiency by up to 67% for aqueous KOH-based electrolyzers and 5% for PEM electrolyzers, reducing the cost of hydrogen production and improving system performance.
Implementation Method 1
PV modules are rated in terms of the power produced under standard test conditions (STC)... most of the solar irradiance is converted to heat with less than 20% converted to electrical energy
Implementation Method 2
transferring heat from the PV array to the electrolyzer, the transferring heat comprising circulating a first fluid
Implementation Method 3
transferring heat from the PV array to the electrolyzer
Implementation Method 4
Certain hydrogen generation devices use electricity to produce hydrogen (and oxygen) by electrolysis of water in an electrolyzer
Data Source
AI summary
One embodiment of the invention includes a process comprising transmitting electrical power produced by a PV array to an electrolyzer and transferring heat from the PV array to the electrolyzer. The resulting process produces renewable hydrogen from solar energy at a lower cost per kg.