Air Handling Unit Setpoint Control for Comfort-Energy Balance
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Solution Overview
Problem
HVAC systems, particularly air handling units, often operate inefficiently due to poor setpoint choices and control strategies, leading to excessive energy consumption and thermal discomfort in buildings.
Innovation Solution
The approach involves using a thermal comfort level index like PMV to optimize setpoints by computing a supply air properties target area, considering geographical location, season, occupant factors, and internal heat gain, and transforming the zone air properties target area into a supply air properties target area using resets and corrections to minimize energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional fixed setpoints are used for air handling units, then control simplicity is maintained, but energy consumption increases and thermal comfort deteriorates
Solution Approach 1:
The patent implements dynamic setpoint optimization by continuously adjusting supply air temperature and humidity setpoints based on real-time zone conditions, outdoor weather, and thermal comfort requirements. The system transitions from fixed static setpoints to dynamic adaptive setpoints that respond to changing environmental conditions and occupancy patterns, thereby reducing energy consumption while maintaining thermal comfort.
Solution Approach 2:
The system employs feedback mechanisms by monitoring zone air temperature, humidity, and thermal comfort indices (such as PMV) and using this information to adjust supply air setpoints. The controller continuously compares actual zone conditions with target conditions and modifies operating parameters accordingly, creating a closed-loop control system that optimizes energy usage while maintaining comfort standards.
2Temperature
If supply air temperature is reduced to improve thermal comfort, then zone comfort increases, but energy consumption for cooling increases
Solution Approach 1:
The patent changes multiple parameters simultaneously rather than adjusting a single parameter. It optimizes the combination of supply air temperature, supply air humidity, and supply air flow rate together to achieve thermal comfort while minimizing total energy consumption. By coordinating changes in temperature and humidity setpoints based on psychrometric relationships and thermal comfort models, the system avoids the energy penalty of overly cold supply air.
Solution Approach 2:
The system uses a composite approach by integrating multiple control strategies including thermal comfort modeling (PMV), psychrometric analysis, and energy optimization algorithms into a unified control framework. This composite methodology combines different technical approaches to achieve both comfort and energy efficiency objectives that cannot be met by single-parameter control.
3Object-affected harmful factors
If outdoor air portion is increased to improve indoor air quality, then IAQ improves, but energy consumption for conditioning outdoor air increases
Solution Approach 1:
The system dynamically adjusts the outdoor air portion by changing the mixing ratio parameter based on zone conditions, outdoor air quality, and energy considerations. It optimizes the balance between outdoor air intake and recirculated air based on real-time conditions, allowing maximum outdoor air when IAQ is prioritized and increased recirculation when energy conservation is the priority, thereby resolving the contradiction between IAQ and energy consumption.
Data Source
AI summary
An approach for providing setpoint optimization for air handling units. An area for such optimization may incorporate choosing a thermal comfort level index, finding a zone air properties target area and computing a supply air properties target area. Beyond the present approach, an outdoor air portion may be optimized, a feasible psychrometric path found, supply airflow versus temperature optimized, and a controller run to meet setpoints.