Split-Flow Condensing Economizer for Gravity Condensate Drainage
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Solution Overview
Problem
Existing condensing heat recovery systems face inefficiencies due to re-evaporation of condensate by hot flue gas and difficulty in maintaining heat exchange tubes, particularly in cylindrical designs where tubes are inaccessible and prone to corrosive condensate drainage issues.
Innovation Solution
A reverse flow economizer design with a main duct and multiple reverse flow passages, where upward flue gas is redirected downward through heat exchange tubes, forming condensate that drains by gravity, and cooled gas is redirected upward through return passages, with adjustable dampers and accessible heat exchange tubes for easy maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If flue gas flows upward across heat exchange tubes with condensate draining downward, then heat recovery is achieved, but condensate is re-evaporated by hot flue gas reducing heat transfer efficiency
Solution Approach 1:
The patent inverts the conventional flow arrangement by directing flue gas downward through the heat exchange tubes instead of upward. This reversal ensures that condensate forms on the outside of tubes and drains downward without being exposed to hot flue gas, preventing re-evaporation and maintaining heat transfer efficiency.
2Loss of energy
If cylindrical economizer design with concentric shells is used, then heat recovery is achieved, but assembly is laborious and maintenance is difficult due to inaccessible tubes
Solution Approach 1:
The patent segments the heat exchange tube bundle into a removable assembly that can be accessed from the front of the economizer. The tubes are arranged in a rectangular configuration within a frame structure, allowing the entire bundle to be removed as a unit for maintenance without disassembling the concentric cylindrical shells.
3Volume of moving object
If heat exchange tubes are positioned in inaccessible zones between flow ducts and outer shells, then compact design is achieved, but maintenance becomes very difficult
Solution Approach 1:
The patent transitions from a three-dimensional nested cylindrical arrangement to a two-dimensional rectangular planar configuration. The heat exchange tubes are arranged in a flat rectangular bundle that can be accessed from the front, converting the maintenance access problem from an intractable three-dimensional constraint to a simple two-dimensional front-access design.
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 design enhances heat transfer efficiency by preventing condensate re-vaporization and simplifies fabrication and maintenance by eliminating nested cylindrical components, allowing for efficient heat recovery and easy access to heat exchange tubes.
Implementation Method 1
the downwardly flowing flue gas interacts with the heat exchange tubes to form condensate and cool the flue gas
Implementation Method 2
the downwardly flowing flue gas interacts with the heat exchange tubes to form condensate and cool the flue gas
Implementation Method 3
a respective bundle of heat exchange tubes in each of the plurality of reverse flow passages, the heat exchange tubes carrying a heat exchange medium
Implementation Method 4
forming condensate that drains by gravity
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A condensing heat exchange economizer wherein upwardly flowing hot flue gas is apportioned by a damper among a plurality of reverse flow passages and redirected to flow in a downward direction through the reverse flow passages over respective bundles of heat exchange tubes carrying a counter-flowing heat exchange medium to form condensate and cool the flue gas. The economizer may comprise a housing having a main flow duct defining a main flow passage in which the damper is located, a pair of conduits opposing one another across the main flow duct and defining respective reverse flow passages, and a pair of return channels opposing one another across the main flow duct and defining respective return flow passages. The cooled flue gas may be merged with the main flow passage at a location above the damper.