Air-mixing plenum and method of mixing flows of air therewith
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Solution Overview
Problem
Existing air-mixing devices in ventilation systems face challenges such as freezing issues due to temperature differences in mixed air streams, leading to equipment damage and increased energy consumption, and require complex solutions that are costly and difficult to manufacture.
Innovation Solution
An air-mixing plenum with a mixing column that combines outdoor and return air streams through a perforated surface, creating a pressure differential to achieve homogeneous mixing without additional zones or moving parts, using thermal insulation to maintain temperature above the dew point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If outdoor air is mixed with return air to limit energy consumption, then energy efficiency is improved, but the temperature can drop below freezing point causing equipment damage
Solution Approach 1:
The patent applies preliminary action by pre-heating the mixed air stream using a heating coil before the air reaches the water coils. This preliminary heating ensures that the air temperature remains above the freezing point throughout the system, preventing equipment damage while still allowing energy-efficient mixing of outdoor and return air.
2Reliability
If glycol is added to the water system to protect from freezing, then freezing protection is improved, but thermal performance of heat transfer coil is greatly reduced
Solution Approach 1:
The patent extracts the freezing protection function from the water system by removing glycol entirely. Instead, it provides freezing protection through a separate air-side heating coil that pre-heats the mixed air stream, allowing the water system to operate with pure water at optimal thermal performance while still preventing freezing through the alternative heating mechanism.
3Stability of the object's composition
If air mixing device is added downstream to break stratification, then mixing performance is improved, but space requirements and manufacturing complexity increase
Solution Approach 1:
The patent merges the air mixing function with the existing plenum structure by incorporating mixing vanes directly into the plenum walls. This integration eliminates the need for separate downstream mixing devices, reducing space requirements and manufacturing complexity while still achieving effective breakdown of air stratification through the strategically positioned vanes.
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 efficient air mixing with reduced stratification, preventing equipment freezing and condensation, improving system efficiency while being simpler and less costly to manufacture.
Implementation Method 1
combines outdoor and return air streams through a perforated surface, creating a pressure differential to achieve homogeneous mixing
Implementation Method 2
using thermal insulation to maintain temperature above the dew point
Data Source
AI summary
A mixing plenum having at least one mixing column configured to be disposed in a first flow of air, the mixing column comprising an elongated body defining a channel extending along a longitudinal axis of said elongated body, the elongated body comprising at least one perforated surface, the at least one perforated surface forming an angle with a flow direction of the first flow of air, wherein the channel is adapted to receive a second flow of air, the mixing column being configured to generate a mixture of the first and second flows of air across the at least one perforated surface.