Coaxial ventilator
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Solution Overview
Problem
Conventional gravity ventilation systems are inefficient due to large duct requirements, air flow stagnation, and difficulty in moving hot air, especially in windy conditions, and often require multiple penetrations and skilled installation.
Innovation Solution
A coaxial ventilator design featuring a thermally conductive outer conduit and a thermally insulative inner conduit, which allows for efficient air circulation and thermal exchange without a separate return duct, using temperature differences to facilitate airflow and incorporating passive evaporative cooling and rainwater collection for enhanced cooling capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional gravity ventilation ducts are used, then air circulation is achieved, but the duct size becomes large and installation becomes difficult
Solution Approach 1:
The patent implements a coaxial duct configuration where an inner return air duct is nested within an outer supply air duct. This nested structure allows both supply and return airflows to occupy the same spatial envelope, dramatically reducing the overall duct size while maintaining adequate airflow capacity for both functions.
Solution Approach 2:
The invention transitions from conventional separate parallel ducts occupying horizontal space to a vertical coaxial arrangement. By utilizing the vertical dimension and nesting ducts along the same central axis, the system achieves efficient air circulation with significantly reduced footprint and installation complexity.
2Ease of operation
If separate return ducts are used, then air flow paths are established, but the system complexity and installation requirements increase
Solution Approach 1:
The patent merges the supply air duct and return air duct into a single coaxial structure, where the inner duct serves as the return path and the outer duct serves as the supply path. This consolidation eliminates the need for separate return ducts while maintaining distinct and efficient airflow paths for both supply and return air.
3Ease of manufacture
If gravity ventilation is used, then no fan is required, but thermal energy consumption increases to maintain adequate air velocity
Solution Approach 1:
The patent modifies the thermal parameters within the duct system by introducing evaporative cooling elements in the return air duct. This changes the temperature and density of the return air, enhancing the buoyancy-driven natural convection currents and increasing air velocity without requiring additional thermal energy input or mechanical fans.
4Temperature
If duct walls are exposed to cooler surrounding air, then heat exchange occurs, but downdrafts are induced causing air flow stagnation
Solution Approach 1:
The patent converts the potentially harmful effect of cooler surrounding air causing downdrafts into a beneficial feature. The outer supply duct is intentionally exposed to cooler ambient temperatures, creating a temperature differential that drives stronger natural convection currents. The cooler air entering the building through the outer duct creates upward buoyancy forces that enhance overall air circulation efficiency.
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 provides efficient air circulation over longer lengths with reduced duct size, eliminates air flow stagnation, and integrates cooling and heating functions in a compact, cost-effective manner, suitable for buildings and other enclosed spaces.
Implementation Method 1
A coaxial ventilator design featuring a thermally conductive outer conduit and a thermally insulative inner conduit, which allows for efficient air circulation and thermal exchange
Implementation Method 2
using temperature differences to facilitate airflow
Implementation Method 3
incorporating passive evaporative cooling and rainwater collection for enhanced cooling capacity
Data Source
AI summary
A coaxial ventilator (20) exchanges atmosphere between parts of a building (22) that are at differing heights. The coaxial ventilator (20) includes an outer conduit (24) that extends from an upper end (42) thereof downward to a lower end (44) thereof. The outer conduit (24) surrounds an inner conduit (62) that extends substantially the entire length of the outer conduit (24). Both the outer and inner conduits (24, 62) are open at their respective upper ends (42, 66) and lower ends (44, 68). Temperatures of atmosphere both surrounding and within the outer conduit (24) and the inner conduit (62) induce an exchange of atmosphere between the coaxial ventilator (20) and surrounding atmosphere.