HVAC systems and methods with improved heat exchangers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas furnaces in HVAC systems face inefficiencies in heat transfer due to lower operating temperatures in secondary heat exchangers, which can lead to thermal energy loss and reduced energy efficiency, particularly because condensate-capable vapors may escape without being fully utilized for heat transfer.
Innovation Solution
Incorporating a plurality of turbulators with a variable pattern, such as a ribbon member with bends and apertures, within the secondary heat exchanger to induce turbulence and enhance contact between combustion products and the heat exchanger, thereby increasing condensate production and thermal mixing, and improving heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional heat exchanger is used in a secondary heat exchanger position, then the structure is simple, but heat transfer efficiency is reduced due to lower operating temperatures and thermal energy loss
Solution Approach 1:
The heat exchanger is divided into multiple sections along the flow path, with each section containing turbulators at specific intervals. This segmentation allows the introduction of turbulence-enhancing features without requiring a complete redesign of the entire heat exchanger structure, thus improving heat transfer efficiency while maintaining manufacturing feasibility.
Solution Approach 2:
Turbulators with curved or spiral configurations are introduced into the heat exchanger passages. These curved structures induce rotational flow and turbulence in the combustion products, enhancing thermal mixing and heat transfer coefficients. The curvature creates centrifugal forces that promote boundary layer disruption and improve condensate formation, thereby reducing thermal energy loss.
2Loss of energy
If turbulators are added to enhance heat transfer, then thermal energy loss is reduced, but device complexity increases
Solution Approach 1:
Turbulators are strategically positioned at specific locations within the heat exchanger where temperature gradients and heat transfer coefficients are most beneficial for condensate formation. Rather than uniformly distributing turbulators throughout the entire heat exchanger, they are placed in zones where they provide maximum thermal energy recovery while minimizing overall structural complexity.
Solution Approach 2:
The design optimizes parameters such as turbulator spacing, size, and configuration to achieve effective turbulence induction with minimal structural addition. By carefully selecting these parameters, the system achieves enhanced heat transfer and reduced thermal energy loss without proportionally increasing device complexity.
3Productivity
If turbulence is increased to enhance condensate production, then heat transfer efficiency is improved, but pressure drop increases
Solution Approach 1:
Rather than creating extreme turbulence throughout the entire heat exchanger, the design applies partial turbulence enhancement through selectively placed turbulators. This approach generates sufficient turbulence to improve condensate production and heat transfer efficiency while avoiding the excessive pressure drop that would result from uniform, intense turbulence throughout the system.
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 use of turbulators with a variable pattern effectively enhances heat transfer by increasing turbulence and condensate formation, reducing thermal energy loss and improving energy efficiency in gas furnaces by maximizing heat transfer while minimizing pressure drop.
Implementation Method 1
The ribbon member is operational to induce turbulence in a heated gas flowing through the conduit
Implementation Method 2
The drawn air is then convectively forced across the heat exchanger
Implementation Method 3
The drawn air is then convectively forced across the heat exchanger
Implementation Method 4
A temperature difference between the hot flow and the cold flow allows the heat exchanger to extract heat from the circulating combustion products and deposit such heat into a convection current of drawn air
Implementation Method 5
the hot flow is typically generated by igniting fuel to produce combustion products
Data Source
AI summary
Systems, tools, and methods are presented that enable a plurality of turbulators to enhance heat transfer within a heat exchanger of a heating, ventilating, and air conditioning (HVAC) system. The plurality of turbulators each include a ribbon member having a variable pattern formed over a length. In one instance, the variable pattern of the ribbon member includes a plurality of bends defining intervals of alternating pitch. The intervals progressively increase in dimension as the ribbon member is traversed over the length. In another embodiment, the intervals contain apertures whose area increases as the length is traversed. Other systems, tools and methods are presented.