OTEC Plant Using SF6 and Widening Conduit for Small Temperature Gradients
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal power generation plants face inefficiencies and environmental concerns due to low energy output, use of hazardous materials, and limitations in locating heat sources and sinks, particularly in ocean thermal energy conversion (OTEC) systems which have a small temperature gradient, leading to low overall efficiency and significant waste heat generation.
Innovation Solution
A closed-loop thermodynamic circuit using a heavy molar mass gas like sulfur hexafluoride (SF6) with a pressurized working fluid that gasifies in a warm evaporator and liquefies in a cold condenser, utilizing a widening ascending conduit and descending pipe to power a turbine, while incorporating a pressuring gas to enhance pressure and density differences, allowing for efficient energy conversion from small temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If OTEC plants use a closed-loop thermodynamic system with working fluid vaporization to generate power, then electricity can be produced from ocean thermal energy, but the small temperature gradient between surface and deep water results in low overall efficiency
Solution Approach 1:
The patent changes the physical parameters of the system by using a working fluid with a boiling point matched to the small temperature gradient (e.g., R-134a boiling at -26.3°C). This allows the fluid to vaporize efficiently at the relatively low temperature of deep ocean water, converting thermal energy to mechanical work with higher efficiency despite the small temperature difference
Solution Approach 2:
The system utilizes phase transitions of the working fluid between liquid and vapor states. The fluid vaporizes in the evaporator when exposed to warm surface water, drives the turbine, then condenses in the condenser when exposed to cold deep water, creating a continuous thermodynamic cycle that efficiently converts thermal energy to mechanical energy
2Loss of energy
If conventional thermal power plants use large temperature differences between heat source and sink, then higher efficiency can be achieved, but the location of heat sources and sinks is limited
Solution Approach 1:
The patent changes the operating parameters by using a working fluid with a low boiling point that can vaporize at the moderate temperatures available from ocean surface water. This eliminates the need for high-temperature heat sources and enables power generation in locations with access to ocean thermal energy, providing location flexibility while maintaining efficiency
Solution Approach 2:
The working fluid acts as an intermediary substance that transfers thermal energy from the ocean water to the turbine. The fluid absorbs heat from warm surface water, vaporizes to drive the turbine, then releases heat to cold deep water, enabling efficient energy conversion without requiring direct thermal contact between the ocean water and the turbine mechanism
3Adaptability or versatility
If OTEC plants are located away from heat sources and sinks, then location flexibility is improved, but efficient heat exchange becomes difficult
Solution Approach 1:
The working fluid serves as an intermediary that can be efficiently heated by warm ocean water in the evaporator and cooled by cold ocean water in the condenser. This intermediary mechanism allows the plant to be located at positions where both warm surface water and cold deep water can be accessed, providing location flexibility while maintaining efficient heat exchange through the fluid's phase change process
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 a significant increase in power generation from natural heat sources with small temperature differences, reducing environmental impact by reutilizing heat and minimizing waste, and can be located away from heat sources and sinks using thermal circuits for efficient heat exchange.
Implementation Method 1
The liquefied working fluid gasifies in an evaporator located at a lower level of said circuit, by gaining heat from a heat source
Implementation Method 2
ascending gasified the working fluid to an upper level through an ascending conduit, increasing its potential energy
Implementation Method 3
liquefying said working fluid in a condenser unit located at said upper level by giving heat to a heat sink
Implementation Method 4
descending the liquefied working fluid because the force of gravity through a descending conduit, and driving a power extraction apparatus
Implementation Method 5
a turbine, which drives an electrical generator
Data Source
AI summary
A thermal energy conversion plant, wherein a pressurized liquefied working fluid gasifies in an evaporator unit located at the lower level of a closed-loop thermodynamic circuit, ascends through a widening ascending conduit to a condenser unit located at the upper level of said thermodynamic circuit, condenses and falls because gravity powering a power extraction apparatus, before entering back into the evaporator, and restarting the cycle. A much lighter pressuring gas could be optionally included in the widening ascending conduit.