Coaxial Nested Duct Ventilator for Gravity-Driven Air Circulation
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Solution Overview
Problem
Conventional gravity ventilation systems are inefficient due to large duct requirements, exposure to cooler air causing stagnation, and difficulty in moving hot air during windy conditions, making them more expensive than fan-based systems and requiring skilled installation.
Innovation Solution
A coaxial ventilator system with a smaller, single-penetration design that uses temperature differences to efficiently circulate air through a nested conduit system, incorporating passive evaporative cooling and thermal storage, and rainwater collection for supplementary water supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional gravity ventilation systems use large ducts to move air, then air circulation is achieved, but the system becomes complex and expensive to install
Solution Approach 1:
The patent employs a coaxial duct configuration where an inner duct is nested within an outer duct. The inner duct carries supply air while the outer duct handles return air, allowing both functions to be integrated in a single compact assembly rather than requiring separate large ducts for each function.
Solution Approach 2:
The invention merges the supply air duct and return air duct into a single coaxial structure, combining multiple ventilation functions (supply, return, and potentially exhaust) into one integrated system that reduces overall complexity and installation requirements.
2Force
If gravity ventilation systems expose duct walls to cooler surrounding air, then air flow is generated, but stagnation occurs due to downdrafts colliding with rising warmer air
Solution Approach 1:
The inner duct is nested within the outer duct in a coaxial arrangement, which isolates the warm rising air in the inner duct from cooler air in the outer duct. This nested configuration prevents downdrafts from colliding with rising air, eliminating stagnation while maintaining reliable air flow.
3Productivity
If gravity ventilation systems use large cross-sections to allow simultaneous air circulation in opposite directions, then air flow in both directions is achieved, but the system size increases
Solution Approach 1:
The coaxial nested duct structure enables bidirectional air circulation by placing the inner duct (carrying air in one direction) inside the outer duct (carrying air in the opposite direction). This nested arrangement achieves simultaneous bidirectional flow without requiring a large cross-sectional area, as each duct handles one direction of flow independently.
4Productivity
If gravity ventilation systems require multiple penetrations through floor slabs, then air distribution is improved, but installation difficulty increases
Solution Approach 1:
The invention combines multiple duct functions (supply, return, and potentially exhaust) into a single coaxial assembly that can be installed through one penetration rather than requiring separate penetrations for each duct, significantly simplifying installation while maintaining effective air distribution.
5Reliability
If gravity ventilation systems require experienced engineers for installation, then system performance is optimized, but installation cost increases
Solution Approach 1:
The pre-fabricated coaxial nested duct assembly is designed as an integrated unit with standardized connections, allowing installers to simply connect the nested components without requiring complex calculations or expert assessment of building suitability, reducing both skill requirements and installation costs.
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 coaxial ventilator system enhances air circulation efficiency, reduces installation complexity, and increases cooling capability without increasing physical fluid capacity, providing a compact, cost-effective solution for ventilation in buildings and other structures.
Implementation Method 1
a ventilation system that exploits a temperature difference between a building's interior and the surrounding atmosphere
Implementation Method 2
Using gravity for moving heating, circulating and ventilating air is a simple technique that has been a well understood and practiced for more than 100 years. Hot air is less dense than cold air and will therefore tend to rise, while cooler air tends to settle.
Implementation Method 3
Another object of the present disclosure is the use of passive evaporative cooling both throughout the day and especially at night.
Data Source
AI summary
A coaxial ventilator exchanges atmosphere between parts of a building that are at differing heights. The coaxial ventilator includes an outer conduit that extends from an upper end thereof downward to a lower end thereof. The outer conduit surrounds an inner conduit that extends substantially the entire length of the outer conduit. Both the outer and inner conduits are open at their respective upper ends and lower ends. Temperatures of atmosphere both surrounding and within the outer conduit and the inner conduit induce an exchange of atmosphere between the coaxial ventilator and surrounding atmosphere.