Stacked Counter-Flow Heat Exchangers for Air-Handling Height Utilization

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Solution Overview

Problem

Counter-flow heat exchangers in air handling units do not maximize heat recovery efficiency due to suboptimal use of available height, as they are not standardized to fit all air handling unit sizes, leading to incomplete utilization of interior space and potential odor transfer risks.

Innovation Solution

The arrangement of multiple counter-flow heat exchangers of varying heights stacked within the air handling unit, with air distributors guiding airflow through each exchanger to prevent mixing, allowing for flexible adaptation to different unit sizes and maximizing interior height usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single standardized counter-flow heat exchanger is used, then the device structure is simple and easy to manufacture, but the available height of the air handling unit is not fully utilized

Engineering Contradiction:
Improvestandardized heat exchanger productionVSAvoidheat exchanging surface area
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The heat exchanger is divided into multiple segments stacked vertically, each segment being a standardized counter-flow heat exchanger unit. This segmentation allows the system to achieve greater total heat exchanging surface area by combining multiple standard units, while maintaining the manufacturing simplicity of individual standardized components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The solution transitions from a single horizontal heat exchanger to a vertical stacking arrangement of multiple heat exchanger segments. By utilizing the vertical dimension (height) of the air handling unit, the system maximizes the use of available space and increases the total heat exchanging surface area without compromising the standardized manufacturing of individual segments.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If multiple heat exchangers of different sizes are arranged to maximize height utilization, then the heat recovery efficiency increases, but the device complexity and assembly difficulty increase

Engineering Contradiction:
Improveheat recovery efficiencyVSAvoidmultiple different-sized components
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system uses multiple identical or similar standardized heat exchanger segments rather than different-sized components. This segmentation approach allows flexible vertical arrangement to match various air handling unit heights while maintaining component uniformity, thereby reducing assembly complexity despite the multi-segment configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The standardized heat exchanger segments are designed to be universal and interchangeable, serving the same function in different positions within the vertical stack. This universality simplifies assembly and maintenance, as the same component design can be used throughout the system regardless of the total number of segments required.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If counter-flow heat exchangers are used instead of cross-flow, then odor transfer is prevented, but the device does not fit optimally with standard air handling unit sizes

Engineering Contradiction:
Improveodor transfer preventionVSAvoidadaptation to air handling unit sizes
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The counter-flow heat exchanger is segmented into multiple vertical units that can be stacked to match different air handling unit heights. This segmentation maintains the odor-preventing counter-flow configuration while providing adaptability to various standard sizes through vertical arrangement of standardized segments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system provides dynamic adaptability by allowing the vertical stacking of heat exchanger segments to be configured according to the specific height requirements of different air handling units. This dynamic configuration capability enables the counter-flow heat exchanger to adapt to various standard sizes while maintaining its superior odor transfer prevention characteristics.

Inventive Principle:
Principle #15Dynamics

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 heat recovery efficiency by fully utilizing the air handling unit's height, minimizing non-active space, and ensuring high air tightness, while allowing for modular and easy assembly, thereby improving the overall performance and adaptability of heat recovery devices.

Implementation Method 1

energy is recovered from a first air stream and is delivered to a second air stream

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

so-called counter-flow heat exchangers are used preferably when a high heat recovery efficiency is wanted

Methodology Applied
Scientific EffectCounter-flow heat exchange: Heat Exchanger

Data Source

PatentEP3259536B1Heat recovery device and method for the use of disposable height of the device in an air handling unit
Publication Date: 2020.04.01 FLAEKTGROUP SWEDEN AB
  • EP3259536B1 patent drawingFigure 1
  • EP3259536B1 patent drawingFigure 2a~2b

AI summary

Method and heat recovery device at an air handling unit (1 ), comprising at least one first and one second counter-flow heat exchanger (2, 3) arranged to exchange energy between a first air stream (4) and a second air stream (5). The device is characterized by that at least the second counter-flow heat exchanger (3) is arranged on-top of the first counter-flow heat exchanger (2), and that the height dimension (b) of the second counter-flow heat exchanger (3) differs from the height dimension (a) of the first counter-flow heat exchanger (2). Further are, in connection to an inlet and outlet of said counter-flow heat exchangers (2, 3), two air distributors (6, 7) arranged, which are dimensionally coordinated with the inlet and outlet of the counter-flow heat exchangers (2, 3) to ensure that all air passes through the air distributors (6, 7), and which air distributors (6, 7) distributes and guides the air to respective from the counter-flow heat exchangers (2, 3) to prevent mixing of the two air streams (4, 5).