Trombe Wall Boundary Layer Disturbance for Heat Transfer
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Solution Overview
Problem
Existing Trombe wall systems exhibit disparities in air circulation and heat exchange due to variations in velocity and temperature profiles within the vertical channel, leading to inefficient thermal energy transfer.
Innovation Solution
Incorporation of means to disturb the air boundary layer on the thermal storage wall, such as motorized transverse rollers or a dielectric barrier discharge system, to modify fluid velocity and enhance heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the Trombe wall uses a simple vertical channel between the transparent cover and thermal storage wall, then the structure is simple and easy to manufacture, but the heat exchange efficiency is reduced due to laminar flow and boundary layer effects
Solution Approach 1:
The patent introduces a vibrating element (such as a vibrating wire or membrane) into the vertical channel to mechanically disturb the laminar flow and boundary layer. This vibration creates turbulence that enhances heat transfer between the air and the thermal storage wall, resolving the contradiction by maintaining structural simplicity while improving heat exchange efficiency through controlled mechanical disturbance.
Solution Approach 2:
The patent employs periodic thermal or mechanical action within the channel, such as periodic heating elements or oscillating flow inducers, to repeatedly disrupt the boundary layer and enhance convective heat transfer. This periodic disturbance prevents the formation of stable laminar flow patterns, thereby improving heat exchange efficiency without complicating the overall structure.
2Use of energy by moving object
If the Trombe wall operates with natural convection only, then the system requires no additional energy input, but the air circulation velocity is insufficient leading to poor heat transfer
Solution Approach 1:
The patent uses a low-energy vibrating element to induce oscillatory flow in the vertical channel. This vibration provides just enough mechanical energy to significantly increase air circulation velocity and disrupt the boundary layer, while consuming minimal energy compared to continuous mechanical forcing. The system thus achieves enhanced heat transfer with only slight additional energy input.
Solution Approach 2:
The patent changes the flow regime parameters by introducing periodic disturbances or vibrations that transition the flow from purely natural convection to a state with enhanced mixing and higher effective velocity. This parameter change allows the system to achieve better heat transfer with minimal additional energy consumption.
3Ease of manufacture
If the Trombe wall uses a large air gap between the transparent cover and thermal storage wall, then the structural design is simplified, but the heat exchange efficiency decreases due to reduced convective interaction
Solution Approach 1:
The patent introduces a vibrating element into the air gap to actively disturb the air flow and enhance convective heat transfer. This vibration compensates for the reduced interaction that occurs in larger air gaps by creating turbulence and preventing the formation of stable thermal layers, thereby maintaining heat exchange efficiency despite the increased gap distance and design flexibility.
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
Enhances thermal energy transfer efficiency by creating turbulence and mixing air flow, improving the phase-shifted energy storage and release mechanism.
Implementation Method 1
A Trombe wall is composed of an exterior glazing placed in front of a dark wall to cause a greenhouse effect which heats the air gap located between the two elements
Implementation Method 2
Openings in the lower and upper parts of the wall then ensure, on demand, air circulation by thermosiphon between the air gap and the interior of the premises to be heated
Implementation Method 3
By regulating the system, the calories are stored in the wall and returned in a phase-shifted manner to the building
Implementation Method 4
the surface of said thermal storage wall facing said transparent cover has at least one means of disturbing the aeraulic boundary layer
Data Source
Figure 1~2
AI summary
The invention relates to a Trombe wall comprising a heat storage wall (1) and a transparent covering (3) defining therebetween a space for air circulation and for heat exchange, said space having, in its lower part, an opening (7) leading into the interior of the building, and, in its upper region, an opening (8) leading into the interior of the building. The surface of said heat storage wall (1) that faces said transparent covering (3) has at least one means for disturbing the thermal and pneumatic boundary layer.