Vertical ground heat exchanger for reducing temperature in carbonaceous shale rock mass and preventing roadbed frost heave
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Solution Overview
Problem
Current ground source heat exchangers have poor thermal conductivity, are prone to corrosion, and suffer from low heat exchange efficiency, leading to ineffective temperature reduction in carbonaceous shale rock mass and increased risk of roadbed frost heave.
Innovation Solution
A vertical ground heat exchanger with a double-layer heat exchange tube component, gas-liquid separator, and refrigeration heat exchange mechanism, utilizing graphene coating and silicon carbide materials for enhanced thermal conductivity and corrosion resistance, along with a compressor unit and flow control valve for improved heat exchange efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PE tube is used for ground heat exchanger, then ease of manufacture is improved, but thermal conductivity deteriorates
Solution Approach 1:
The patent employs composite materials including graphene-coated tubes and silicon carbide materials to enhance thermal conductivity while maintaining ease of manufacture. The graphene coating on the heat exchange tubes creates a composite structure that significantly improves thermal performance compared to conventional PE tubes, directly resolving the contradiction between ease of manufacture and thermal conductivity.
2Strength
If metal material is used for heat exchanger, then strength is improved, but corrosion resistance deteriorates
Solution Approach 1:
The patent uses composite material structures where metal tubes are coated with corrosion-resistant materials or replaced with inherently corrosion-resistant materials like silicon carbide. This composite approach maintains the structural strength provided by metal while adding corrosion protection, thereby resolving the contradiction between strength and corrosion resistance.
Solution Approach 2:
The patent introduces an intermediary protective layer (such as graphene coating or other protective coatings) between the metal tube and the corrosive environment. This intermediary layer acts as a barrier that prevents direct contact between the metal and corrosive substances, maintaining both strength and corrosion resistance.
3Device complexity
If conventional heat exchanger structure is used, then device complexity is reduced, but heat exchange efficiency deteriorates
Solution Approach 1:
The patent introduces a double-layer heat exchange tube structure with internal and external heat exchange surfaces, effectively adding a dimensional aspect to the heat exchange process. This double-layer configuration increases the heat exchange area and improves efficiency without significantly increasing device complexity, as the additional layer is integrated into the existing tube structure.
Solution Approach 2:
The patent applies localized enhancements such as graphene coating on specific sections of the heat exchange tubes or in the heat exchange mechanism. This local quality improvement focuses thermal conductivity enhancement where it is most needed for heat exchange, improving overall efficiency without requiring complete redesign of the entire system.
4Reliability
If temperature in rock mass is reduced, then roadbed frost heave prevention is improved, but energy consumption increases
Solution Approach 1:
The patent utilizes phase transition of the working fluid (evaporation and condensation) to achieve heat exchange. During evaporation, the fluid absorbs heat from the rock mass, reducing temperature. During condensation, it releases heat. This phase transition mechanism provides efficient heat transfer with relatively low energy consumption compared to conventional cooling methods, resolving the contradiction between frost heave prevention and energy consumption.
Solution Approach 2:
The heat exchanger system is designed to utilize the natural temperature differential between the rock mass and the working fluid, allowing the system to self-regulate to some extent. The evaporator absorbs heat naturally from the warmer rock mass, and the condenser releases heat to the cooler environment, reducing the need for additional energy input while maintaining effective temperature control for frost heave prevention.
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 solution provides a reliable, efficient, and cost-effective heat exchange system that uniformly dissipates heat, reducing the risk of roadbed frost heave and maintaining structural integrity by improving heat exchange efficiency and corrosion resistance.
Implementation Method 1
By continuous heat exchange between the refrigeration heat exchange mechanism and a heat source in external rock-soil body, a low-temperature and low-pressure gas is formed
Implementation Method 2
The low-temperature and low-pressure gas enters the heating mechanism to form high-temperature and high-pressure gas
Implementation Method 3
The high-temperature and high-pressure gas passes through the double-layer heat exchange tube component for heat releasing
Implementation Method 4
the gas-liquid separator performs diffluence on a gas and liquid, which pass through the double-layer heat exchange tube component
Implementation Method 5
utilizing graphene coating and silicon carbide materials for enhanced thermal conductivity
Implementation Method 6
silicon carbide materials for enhanced thermal conductivity and corrosion resistance
Data Source
AI summary
A vertical ground heat exchanger for reducing the temperature in the carbonaceous shale rock mass and preventing roadbed frost heave includes a heating mechanism, a heat releasing component respectively connected to both ends of the heating mechanism and a refrigeration heat exchange mechanism. The refrigeration heat exchange mechanism is connected to the lower end of the heating mechanism through a heat transfer pipeline and communicates with the heat releasing component. The heat releasing component includes a double-layer heat exchange tube component, a gas-liquid separator and a branch tube, wherein the double-layer heat exchange tube component is respectively connected to the both ends of the heating mechanism, the gas-liquid separator is connected to the double-layer heat exchange tube component, and the branch tube is connected between the gas-liquid separator and the refrigeration heat exchange mechanism. The double-layer heat exchange tube component includes an upper bellows and a lower bellows.