Solar Air-Liquid Heat Exchanger With Baffles for Turbulent Flow
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Solution Overview
Problem
Existing heat exchange systems are inefficient for heating liquids with air due to the significant density difference between air and liquids, requiring large volumes of air to achieve heat transfer, and lack effective methods to create high turbulence for enhanced heat exchange.
Innovation Solution
An air-liquid heat exchanger design featuring an insulated chamber with a coil member and baffle members that create turbulence by forcing air to pass between coil windings multiple times, utilizing a double-action deflector with a rounded shape and shear barrier to enhance air flow turbulence and energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional heat exchanger design is used, then the structure is simple, but the heat transfer efficiency is low due to insufficient air-liquid heat exchange
Solution Approach 1:
The heat exchanger is divided into multiple segments including a plenum chamber, multiple coils positioned at different heights, and multiple baffles. Each segment serves a specific function: the plenum chamber distributes air, the coils provide heat transfer surfaces at different levels, and the baffles create turbulence. This segmentation allows efficient heat transfer while maintaining manageable structural complexity.
Solution Approach 2:
The invention transitions from a single-plane heat exchange design to a multi-dimensional structure with coils positioned at different vertical heights within the plenum chamber. Air flows horizontally while heat transfer occurs across multiple vertical levels, creating three-dimensional heat exchange pathways that significantly improve efficiency without proportionally increasing complexity.
2Productivity
If air volume is increased to compensate for low density, then heat transfer potential improves, but the system size and complexity increase
Solution Approach 1:
The invention changes the flow regime parameter from laminar to turbulent flow by introducing baffles and optimizing air velocity. This parameter change dramatically improves heat transfer efficiency without requiring proportional increases in air volume or exchanger size, as turbulence enhances convective heat transfer coefficients.
Solution Approach 2:
The baffles create periodic turbulence and recirculation patterns within the plenum chamber, causing air to repeatedly contact different portions of the coils. This periodic action maximizes heat transfer within a compact volume by ensuring thorough mixing and multiple contact opportunities between air and heat transfer surfaces.
3Productivity
If air flow velocity is increased to enhance heat transfer, then heat exchange efficiency improves, but turbulence control becomes difficult
Solution Approach 1:
The baffles are strategically positioned to automatically generate turbulence and recirculation patterns based on the natural air flow through the system. The structure itself serves the function of flow control without requiring external actuators or complex control mechanisms. Air velocity and turbulence are self-regulated by the geometric configuration of the baffles and coils.
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 design achieves a 20% efficiency improvement in heat transfer by creating repetitive turbulence and multiple contacts between air and the coil, ensuring uniform energy distribution and high efficiency in energy transfer from air to liquid.
Implementation Method 1
A coil for carrying a liquid wherein the coil consists of a long winding pipe forming tube bundles passing through all of the plurality of chambers
Implementation Method 2
force the air to pass in between the coil windings and increase the air contact with the coil and provide a large heat exchange
Implementation Method 3
Several baffle members are placed each side of the coil member and an interior area of the insulated chamber and force air to circulate multiple times through the coil member, thereby allowing for an efficient exchange from the hot air to the heat transfer liquid
Implementation Method 4
An insulated chamber adapted to allow hot air to pass therethrough
Data Source
AI summary
A liquid-gas heat exchanger for use in a heat exchange system using solar energy has an insulated chamber adapted to allow hot air to pass therethrough. A coil member extends through the insulated chamber and is adapted to allow a heat transfer liquid to pass into and then out of the insulated chamber. The spacing between the windings of the coil are predefined and the coil is in a predetermined position inside the insulated chamber, so as to force the air to pass in between the coil windings and increase the air contact with the coil and provide a large heat exchange. Several baffle members are placed each side of the coil member and an interior area of the insulated chamber and force air to circulate multiple times through the coil member, thereby allowing for an efficient exchange from the hot air to the heat transfer liquid. The insulated containe contains the heat exchanger which is comprised of a plurality of chambers, wherein each the plurality of chambers has a repeating pattern of shapes wherein each of the chamber of th plurality of chambers consists of one deflector which deflector being opposite to another deflector, which other deflector is a mirror image of its opposite deflector but shifted approximately half a the wall length. Each of the deflectors is defined by a specific sequence of components starting with a rounded wall from which extends a shear barrier and the wall is terminated by a diverter.