HVAC Airflow Bypass Layout for Independent Humidity Control
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Solution Overview
Problem
Conventional HVAC systems struggle to independently control temperature and humidity, often leading to inefficient energy use and undesirable changes in either temperature or humidity levels when trying to maintain desired conditions in enclosed spaces.
Innovation Solution
An energy exchange system with a supply flow path including a central sub-path connected to a bypass sub-path and a delivery sub-path, featuring a sensible heat exchanger and a first coil, along with bypass and re-direct dampers, allows for selective control of air flow to bypass or re-direct air through heat exchangers, enabling independent control of temperature and humidity adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vapor compression system is used to dehumidify hot and humid ambient air, then the supply air is cooled to remove moisture, but the air is overcooled and requires reheating which is inefficient
Solution Approach 1:
The system segments the air conditioning process into two independent paths: a central sub-path with full conditioning equipment (sensible heat exchanger, cooling coil, heating coil) and a bypass sub-path that allows air to bypass these components. This segmentation enables selective application of conditioning treatments, avoiding the need to overcool all air for dehumidification purposes.
Solution Approach 2:
The system applies different conditioning treatments to different portions of the air stream based on local requirements. The bypass damper controls the proportion of air that receives full conditioning versus bypass treatment, allowing precise local control of temperature and humidity levels in different zones or at different times.
2Temperature
If the outdoor air temperature decreases while cooling an enclosed space, then the available energy to reheat air decreases, but the air supplied may become lower than desired
Solution Approach 1:
The system performs preliminary heating of the air stream in the central sub-path through the heating coil before the air is delivered to the enclosed space. This preliminary action ensures that even when outdoor air temperature is low and reheating energy is limited, the supply air temperature can be maintained at desired levels by pre-heating the air in the controlled environment of the HVAC system.
Solution Approach 2:
The system introduces an intermediary heating coil in the central sub-path that acts as a mediator between the cooling process and the final supply air temperature. This intermediary component allows independent control of heating without relying solely on outdoor air temperature, enabling precise temperature management even when outdoor conditions are unfavorable.
3Temperature
If typical conditioning systems are used to change temperature, then humidity changes occur but cannot be controlled independently
Solution Approach 1:
The system segments the air handling functions into separate components: a sensible heat exchanger for temperature control, a cooling coil for dehumidification, and a heating coil for humidification/temperature adjustment. The bypass damper allows selective routing of air through different combinations of these components, enabling independent control of temperature and humidity by adjusting the proportion of air that passes through each component.
Solution Approach 2:
The system dynamically adjusts the air flow distribution between the central sub-path and bypass sub-path through the bypass damper, and further dynamically controls the operation of the sensible heat exchanger, cooling coil, and heating coil. This dynamic control allows the system to independently vary temperature and humidity settings according to different environmental conditions and occupancy 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
This system allows for precise control of temperature and humidity levels, reducing energy consumption and preventing over-cooling or over-heating, while maintaining desired conditions in enclosed spaces by allowing air to bypass or re-heat through the system.
Implementation Method 1
A sensible heat exchanger configured to condition the supply air is disposed within the central sub-path
Implementation Method 2
A first coil configured to further condition the air is disposed within the central sub-path downstream from the sensible heat exchanger
Data Source
AI summary
An energy exchange system includes a supply flow path including a central sub-path connected to a bypass sub-path that is, in turn, connected to a delivery sub-path that connects to the enclosed structure. A sensible heat exchanger configured to condition the supply air is disposed within the central sub-path. The bypass sub-path connects to the central sub-path upstream from the sensible heat exchanger within the central sub-path. A first coil configured to further condition the supply air is disposed within the central sub-path downstream from the sensible heat exchanger. A bypass damper is disposed within the bypass sub-path. The bypass damper is configured to be selectively opened and closed. The bypass damper allows at least a portion of the supply air to pass through the bypass sub-path into the delivery sub-path and bypass the sensible heat exchanger and the first coil when the bypass damper is open.