Geothermal energy mining system using stepped gravity-assisted heat pipe having no accumulated liquid effect
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Solution Overview
Problem
Existing gravity-assisted heat pipes used in geothermal energy recovery face reduced heat transfer efficiency when extracting deep geothermal resources due to liquid accumulation, which prevents the working medium from vaporizing at deeper depths, leading to inefficiencies in heat transfer.
Innovation Solution
A ladder-structural gravity-assisted-heat-pipe geothermal energy recovery system without liquid accumulation, featuring a heat pipe with a ladder structure and liquid-level control tubes, where the liquid level is maintained below a certain level through liquid-level control tubes, ensuring complete wetting and preventing vaporization issues, and includes a condenser and liquid tank for efficient heat transfer and circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid column is formed at the heated section to ensure complete wetting, then the heated section is completely wetted, but the saturation temperature increases with depth due to gravity pressure, preventing vaporization at deeper levels and reducing heat transfer efficiency
Solution Approach 1:
The heat pipe is divided into multiple sections with division plates at different heights. Each section has its own liquid-level control tube, creating segmented zones that independently control liquid levels. This segmentation allows the liquid column to be maintained at appropriate heights in each section, preventing excessive pressure buildup that would inhibit vaporization while ensuring complete wetting of the heated section.
Solution Approach 2:
Liquid-level control tubes act as intermediary devices between the liquid working medium and the heated section. These tubes provide a controlled pathway for liquid to enter the heat pipe sections, regulating the liquid level to optimal heights. The intermediary structure ensures that liquid is supplied at the right pressure and level, enabling both complete wetting and effective vaporization without the harmful effects of excessive liquid column pressure.
2Reliability
If the liquid level depth increases to ensure complete wetting, then the heated section is completely wetted, but the working medium cannot vaporize due to higher saturation temperature, resulting in reduced heat transfer efficiency
Solution Approach 1:
By segmenting the heat pipe into multiple sections with division plates, the liquid column is divided into smaller segments. Each section maintains a limited liquid level depth through its own liquid-level control tube, preventing the accumulation of excessive liquid depth that would raise saturation temperature beyond vaporization capability. This segmentation enables sustained vaporization and efficient heat transfer while ensuring complete wetting.
Solution Approach 2:
The liquid-level control tubes provide dynamic control of liquid levels in each section. As liquid accumulates, the control tubes regulate the level to prevent excessive depth, allowing the system to dynamically maintain optimal liquid levels for both wetting and vaporization. This dynamic adjustment ensures that the working medium can continuously vaporize and transfer heat efficiently.
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 design enhances heat transfer efficiency by preventing liquid accumulation and ensuring vaporization, allowing for the effective exploitation of deep geothermal resources without the need for auxiliary power and minimizing medium loss and environmental pollution.
Implementation Method 1
the liquid working medium flows from the liquid tank 3 through the return pipe 7 into each of the sections of the space between the outer pipe 8 and the inner pipe 9 sequentially, absorbs heat from the high-temperature rock 6 through a wall of the outer pipe 8, and vaporizes into a gaseous working medium
Implementation Method 2
the gaseous working medium gets into the inner pipe 9 and rises to the condenser 2
Implementation Method 3
the condenser 2 exchanges heat with environment to condense the gaseous working medium into the liquid working medium
Implementation Method 4
wherein when a liquid level in one of the sections is higher than the tube, a liquid working medium flows to a lower section through the tube
Data Source
Figure 1
Figure 2
AI summary
A ladder-structural gravity-assisted-heat-pipe geothermal energy recovery system without liquid-accumulation effect, comprises a ladder-structural gravity-assisted heat pipe, a condenser, and a liquid tank. The ladder-structural gravity-assisted heat pipe comprises a return pipe, an outer pipe and an inner pipe. The return pipe is provided in a space between the outer pipe and the inner pipe and communicated with the liquid tank, and the space between the outer pipe and the inner pipe is divided to form a ladder structure. A liquid working medium flows from the liquid tank through the return pipe into each of the sections sequentially, absorbs heat from the high-temperature rock through a wall of the outer pipe, vaporizes into a gaseous working medium, gets into the inner pipe, and rises to the condenser to condense and flows to the liquid tank again to circulate. Compared with the prior art, the heated section of the heat pipe is divided to form a ladder structure in the present invention, such that the liquid level in each section is limited below a certain level via a liquid-level control tube. Such design allows the heated section to be completely wetted while avoids the problem that the working medium is unable to vaporize due to excessively high liquid level, and thereby greatly improves the heat transfer efficiency in geothermal energy recovery using ultra-long heat pipes.