Nested Double-Coil Condensing Exchanger for Condensate Evacuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional condensation heat exchangers with plain surface serpentine coils suffer from liquid deposition due to condensation of combustion products within exchange interspaces, limiting their application to specific boiler arrangements and reducing efficiency.
Innovation Solution
A double tubing condensation exchanger is designed with a plain tubing coil nested inside a corrugated coil, featuring a pseudo-pentagonal, rectangular, or ovoidal cross section, allowing for efficient heat transfer and preventing liquid deposition in the interspaces by ensuring condensate formation only near the corrugated outer coil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plain surface serpentine coil is used in a condensation heat exchanger, then the structure is simple and easy to manufacture, but liquid deposition occurs due to condensation of combustion products within exchange interspaces
Solution Approach 1:
The patent implements a nested coil configuration where a first serpentine coil is positioned inside a second serpentine coil, creating multiple interspaces. This nested arrangement prevents liquid deposition by ensuring condensate forms only near the outer corrugated coil where it can be effectively evacuated, while the inner coil remains protected from liquid accumulation.
Solution Approach 2:
The patent applies different surface profiles to different coils: the outer coil features a corrugated profile while the inner coil has a plain profile. This local differentiation optimizes heat transfer characteristics in different regions and ensures that condensation occurs preferentially in the outer interspaces where liquid evacuation is most effective.
2Device complexity
If a single coil configuration is used, then the device complexity is low, but the energetic efficiency is limited and specific load loss is higher
Solution Approach 1:
The nested dual-coil configuration increases the effective heat transfer surface area and creates multiple thermal exchange pathways. The inner and outer coils operate in parallel, allowing more complete heat recovery from combustion products and reducing specific load loss while maintaining manageable device complexity.
Solution Approach 2:
The patent transitions from a single-plane coil arrangement to a three-dimensional nested configuration. This spatial arrangement allows simultaneous heat exchange across multiple surfaces and creates optimized flow paths for both combustion products and thermal carrier fluid, enhancing energetic efficiency.
3Loss of energy
If the first coil is arranged inside the second coil with conforming cross section, then the thermal exchange surface is optimized, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies that only the outer coil requires a corrugated profile while the inner coil can be plain, reducing manufacturing complexity. The conforming cross-section requirement is applied selectively to optimize thermal contact where most beneficial, rather than requiring precision throughout the entire assembly.
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
This configuration enhances energetic efficiency, reduces specific load loss, and improves condensate evacuation, offering higher flexibility and reliability compared to single coil systems, while maintaining a favorable cost-to-benefit ratio.
Implementation Method 1
hot gaseous fluids lick both corrugated tubing 3 surface and plain tubing 2 surface, both with thermal carrier liquid to be heated
Implementation Method 2
Fumes, once reached upper bottom 5, are forced to invert their direction, again going down toward lower bottom through passages realised between corrugated tubing 3 and plain tubing 2
Implementation Method 3
Fumes, during the path, are cooled by system water up to reaching dew temperature and thus releasing condensation latent heat
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention concerns a double tubing condensation exchanger (1) for heating water and/or for producing sanitary hot water, characterized in that it provides a first coil (2) with a plain surface and a second coil (3) with a corrugated surface, provided in parallel each other, said first (2) and second (3) coils being spiral wound, a thermal carrier fluid circulating, independently, inside said first and second coil, said first (2) coil exchanging heat with combustion fumes mainly by irradiation and convection, and said second coil (3) exchanging heat with combustion fumes mainly by condensation.