Offset-Flow Filter Heat Exchanger for Grease-Laden Flue Gas
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Solution Overview
Problem
Commercial kitchens face inefficiencies in heat recovery and particulate filtration due to existing heat exchanger designs being distant from heat sources, causing thermal energy loss and clogging issues, which are costly and time-consuming to retrofit.
Innovation Solution
A filter unit with a heat exchanger coated with reduced-friction material and finned conduits that maximizes heat transfer by redirecting hot gases through baffles and fins, allowing for efficient heat capture and particulate filtration, compatible with existing flue systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a heat exchanger is positioned downstream of a grease filter, then the filter can capture particulates, but heat transfer efficiency decreases because the heat exchanger is located at a significant distance from the heat source
Solution Approach 1:
The patent combines the heat exchanger and grease filter into a single integrated unit, eliminating the need for separate components positioned at different locations. The heat exchanger surfaces are positioned within the filter housing to directly capture heat from exhaust gases passing through the filter media, thereby reducing thermal energy loss while maintaining filtration capability.
Solution Approach 2:
The patent incorporates heat transfer surfaces in multiple orientations within the filter housing, including horizontal and inclined surfaces. This multi-dimensional arrangement maximizes heat capture from gases flowing through the filter while maintaining compact positioning near the heat source, resolving the contradiction between heat transfer efficiency and device complexity.
2Productivity
If existing grease filters are used, then particulate matter can be captured, but air flow is significantly impeded when congested with grease, reducing ventilation efficiency
Solution Approach 1:
The filter media is divided into multiple horizontal and inclined surfaces arranged in stages within the housing. This segmentation allows grease to be captured and drained at multiple points along the flow path, preventing congestion that would impede air flow while maintaining effective particulate capture across the entire filter area.
Solution Approach 2:
The patent employs inclined and curved surfaces within the filter housing that facilitate smooth gas flow and grease drainage. These curved geometries reduce flow resistance compared to flat, congested filter surfaces, maintaining ventilation efficiency while effectively capturing particulates.
3Loss of energy
If heat exchangers are retrofitted into existing kitchen equipment, then heat recovery can be achieved, but the conversion requires an entirely new flue hood assembly and substantial piping, making it time-consuming and expensive
Solution Approach 1:
The filter unit is designed as a universal component that can be installed in various exhaust system configurations without requiring custom flue hood assemblies or extensive piping modifications. The integrated heat exchanger and filter design allows it to function as a standalone unit that can be retrofitted into existing systems with minimal structural changes.
Solution Approach 2:
The patent extracts the heat recovery function from complex integrated systems and incorporates it directly into the filter housing itself. This extraction allows the heat exchanger to be positioned within the existing filter assembly, eliminating the need for separate heat recovery equipment and substantial piping installations.
4Use of energy by moving object
If the heat source is turned off, then energy consumption decreases, but grease quickly solidifies within existing filters, causing maintenance issues
Solution Approach 1:
The inclined and curved surfaces within the filter housing prevent grease from solidifying in stagnant positions by facilitating continuous drainage toward collection points. This geometric design ensures that even when the heat source is off, grease flows smoothly to drainage areas rather than accumulating and hardening within the filter media, reducing maintenance requirements.
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 heat transfer efficiency and reduces maintenance costs by maximizing heat exposure and preventing particulate buildup, allowing for efficient retrofitting into existing kitchen ventilation systems.
Implementation Method 1
transfers heat from the hot gas to a circulating fluid
Implementation Method 2
heat transfer efficiency
Implementation Method 3
hot gas is drawn through the at least one entrance opening and across the heat exchanger
Implementation Method 4
heat exchanger coated with reduced-friction material
Implementation Method 5
baffles and fins, allowing for efficient heat capture and particulate filtration
Data Source
AI summary
A filter unit heat exchanger is provided that may include a housing substantially surrounding a heat exchange assembly. Provided through the housing are one or more tortuous fluid flow paths used to direct airflow therethrough around portions of the heat exchange assembly for efficient operation. The tortuous path(s) may be provided by one or more nozzle openings on an input side of the housing and one or more diffuser openings on an output side of the housing, where the nozzle openings and diffuser openings are offset to cause desired airflow deflection. The filter unit may include desired symmetries to improve manufacturability and/or installation.