Dual-Plenum Chilled Beam Airflow for Variable Thermal Loads
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Solution Overview
Problem
Active chilled beams face inefficiencies due to operating outside their optimal performance range as they are designed to handle increasing space loads, leading to high airflow requirements and increased costs, while they cannot satisfy latent loads and require additional air handling systems.
Innovation Solution
The implementation of chilled beams with separate primary and secondary plenums that generate induction jets, allowing for adjustable airflow through a heat exchanger, enabling the use of secondary air to supplement ventilation during low ventilation requirements and modulating airflow based on thermal loads, thereby optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If active chilled beams are designed to handle increasing space loads with higher airflow, then the cooling capacity is improved, but the system operates outside its optimum performance range and energy efficiency deteriorates
Solution Approach 1:
The system is divided into two separate airflows: primary ventilation airflow and secondary recirculating airflow. This segmentation allows independent optimization of each flow's function and volume, enabling the chilled beam to handle increased cooling loads through secondary air without compromising primary ventilation requirements or operating efficiency.
Solution Approach 2:
The system dynamically adjusts the ratio of primary to secondary airflow based on varying thermal loads and ventilation requirements. During high cooling demand, secondary recirculating airflow is increased to meet the load while maintaining optimal primary airflow for ventilation, allowing the system to adapt to changing conditions without operating outside its performance range.
2Object-affected harmful factors
If primary ventilation airflow is increased to satisfy latent load, then the latent load is handled, but the ventilation load requires larger air handling systems and increased energy consumption
Solution Approach 1:
The latent load handling function is extracted from the primary ventilation airflow and assigned to the secondary recirculating airflow. This allows the primary system to be sized only for ventilation requirements while the secondary system handles sensible cooling and latent load, separating the functions and reducing overall energy consumption.
Solution Approach 2:
The secondary recirculating airflow serves multiple functions: it provides additional cooling capacity, handles latent load through the heat exchanger, and can be adjusted independently of ventilation requirements. This multi-functionality eliminates the need to oversize the primary ventilation system for latent load handling.
3Power
If secondary recirculating airflow is used to satisfy thermal load, then the cooling capacity is improved, but the system complexity increases with separate primary and secondary plenums
Solution Approach 1:
The primary and secondary airflow systems are merged into a single chilled beam housing with integrated heat exchanger. Both airflows pass through the same heat exchange coils, allowing coordinated thermal processing while maintaining separate flow paths. This integration reduces space requirements and simplifies installation compared to completely separate systems.
Solution Approach 2:
The secondary recirculating airflow path is nested within the primary ventilation system structure. The heat exchanger serves both flows sequentially or in parallel depending on configuration, with the secondary airflow being drawn from and returned to the same space, creating a nested arrangement that improves capacity without proportionally increasing complexity.
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 solution enhances the operational efficiency of chilled beams by allowing for flexible airflow management, reducing energy consumption, and effectively handling both sensible and latent loads, thus improving overall system performance and cost-effectiveness.
Implementation Method 1
Each of the primary and secondary air plenums opens into a mixing chamber by means of jet openings configured to induce a flow of air through a heat exchanger
Implementation Method 2
induce a flow of air through a heat exchanger
Data Source
AI summary
A chilled beam has separate primary and secondary inlets and plenums each or which generates separate sets of induction jets to draw air through a chilled beam heat exchanger. Various system and method embodiments are described as well as features usable in conventional active chilled beams to facilitate the use variable thermal and ventilation load applications.