Dedicated outdoor air system configuration systems and methods
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Solution Overview
Problem
Existing HVAC systems with horizontally disposed heat exchangers in dedicated outdoor air systems suffer from reduced air flow efficiency due to the use of knee walls, increased footprint, and pressure drops, which affect the overall performance and efficiency of the system.
Innovation Solution
The system reorients the heat exchanger vertically within the HVAC unit, eliminating the knee wall and allowing for a more direct air flow path between the blower and heat exchanger sections, enhancing air flow efficiency and reducing the system's footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the heat exchanger is disposed horizontally in the dedicated outdoor air system, then the system structure is simplified, but air flow efficiency is reduced due to pressure drops and the need for knee walls
Solution Approach 1:
The heat exchanger is inverted from a horizontal disposition to a vertical disposition within the enclosure. This inversion eliminates the need for knee walls and creates a more direct air flow path from the blower section through the heat exchanger to the air outlet, thereby improving air flow efficiency while maintaining structural simplicity
Solution Approach 2:
The heat exchanger is reoriented from a horizontal plane to a vertical plane, changing the dimensional arrangement of components. This vertical orientation allows air to flow upward through the heat exchanger sections without requiring horizontal directional changes, reducing pressure drops and improving overall air flow efficiency
2Ease of operation
If the heat exchanger is disposed horizontally, then the air flow path is straightforward, but the system footprint increases due to knee wall requirements
Solution Approach 1:
By inverting the heat exchanger from horizontal to vertical orientation, the knee walls are eliminated. The air flow path remains straightforward but now flows vertically through the heat exchanger sections, reducing the horizontal footprint of the system while maintaining operational simplicity
Solution Approach 2:
The knee walls are extracted or removed from the system design. By eliminating these structural elements that were necessary for horizontal heat exchanger support, the system footprint is reduced while the air flow path is maintained through the vertical heat exchanger configuration
3Ease of manufacture
If the heat exchanger is disposed horizontally, then installation is conventional, but thermal efficiency is reduced due to pressure drops
Solution Approach 1:
The heat exchanger is inverted to a vertical orientation, which eliminates pressure drops associated with horizontal flow through knee walls. This improves thermal efficiency by allowing more effective heat transfer between the air and heat exchanger surfaces, while the vertical configuration remains consistent with conventional installation practices
Solution Approach 2:
The vertical heat exchanger configuration enables continuous, uninterrupted air flow through the heat transfer surfaces without the pressure drops and flow separations caused by knee walls. This continuous flow maintains optimal thermal exchange throughout the entire air passage through the heat exchanger
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 increases air flow efficiency and thermal efficiency by eliminating pressure drops and reducing the system's size, resulting in improved performance and cost-effectiveness.
Implementation Method 1
a heat exchanger to condition the environmental air flow, generating the conditioned air flow
Implementation Method 2
a blower to motivate the environmental air flow from the air inlet to the heat exchanger
Data Source
AI summary
A direct outdoor air system may include an enclosure having an air inlet to direct environmental air into the enclosure, a heat exchanger section to receive the environmental air and direct conditioned air to an air outlet of the enclosure, and a blower section to receive the environmental air from the air inlet and direct the environmental air to the heat exchanger section via an air flow path between the blower section and the heat exchanger section. The air outlet may direct the conditioned air to a conditioned space. The direct outdoor air system may also include a heat exchanger disposed in the heat exchanger section to condition the environmental air, generating the conditioned air, and a blower disposed in the blower section to motivate the environmental air through the air flow path. Additionally, a heat exchange area of the heat exchanger may be oriented vertically relative to gravity.