HVAC Control Using Supply and Return Air Feedback to Prevent Load Hopping
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Solution Overview
Problem
Modern HVAC systems in commercial spaces operate inefficiently due to independent unit control, leading to 'load hopping' and high power consumption, resulting in uneven temperature distribution and increased greenhouse gas emissions.
Innovation Solution
The system controls HVAC units using both return air and supply air temperature sensors to prioritize cooling valve operation over fan speed, ensuring efficient temperature maintenance and reducing power consumption by minimizing fan usage and avoiding load hopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If HVAC units operate independently based only on return air temperature, then each unit can maintain its individual space temperature, but load hopping occurs and power consumption increases
Solution Approach 1:
The patent implements a feedback mechanism where each HVAC unit receives temperature signals from both its own return air sensor and supply air sensor, and also receives operational status signals from neighboring units. This feedback loop allows units to coordinate their operation, preventing simultaneous full-capacity operation and eliminating load hopping, thereby reducing overall power consumption while maintaining individual space temperature control
Solution Approach 2:
The patent merges the control logic of individual units by introducing inter-unit communication that allows them to share temperature data and operational status. This merging enables coordinated operation where units can sense each other's activity and adjust accordingly, transforming independent operation into a semi-coordinated system that reduces energy waste from competing operations
2Device complexity
If HVAC units use only return air temperature sensors, then the system is simpler, but temperature control precision deteriorates and load hopping occurs
Solution Approach 1:
The patent makes the temperature sensing system multi-functional by having each HVAC unit utilize both its own return air temperature sensor and supply air temperature sensor. This universal use of dual sensors serves multiple purposes: monitoring individual unit performance, detecting room temperature trends, and coordinating with neighboring units to prevent load hopping, thereby improving temperature control precision without proportionally increasing complexity
Solution Approach 2:
The supply air temperature sensor acts as an intermediary measurement point that provides information about the cooling effect being delivered to the room. By incorporating this intermediate measurement, the system gains better precision in controlling temperature without requiring direct measurement at every location, as the supply air temperature serves as a proxy for room temperature trends
3Reliability
If HVAC units operate at full capacity independently, then individual space cooling is maintained, but uneven temperature distribution and localized heating occur
Solution Approach 1:
The patent introduces dynamic operation modes where HVAC units can switch between full capacity, partial capacity, and idle states based on real-time temperature signals from both themselves and neighboring units. This dynamic adjustment prevents the static full-capacity operation that causes temperature unevenness, allowing units to modulate their output for smoother, more uniform temperature distribution while maintaining reliable individual space control
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 approach reduces energy consumption by up to 25% and decreases greenhouse gas emissions, saving corporations millions in power costs while maintaining consistent environmental conditions.
Implementation Method 1
a cooling valve, and a processor that is coupled to at least one fan and at least one cooling valve
Implementation Method 2
The presently disclosed invention improves upon known methods and systems of controlling HVAC systems by controlling the systems to operate more efficiently
Implementation Method 3
a fan, a cooling valve, and a processor that is coupled to least one fan and at least one cooling valve
Data Source
AI summary
Systems and methods of controlling a heating, ventilating, and air conditioning system are provided that operate according to signals returned from return air temperature sensors as well as the supply air temperature sensors. Using predetermined temperature setpoints, return temperature information, and supply temperature information, the HVAC system is configured to maintain the temperature of a room first, by the use of its cooling valve, and second and only when the capacity of the cooling valve has peaked, by use of the fan. The presently disclosed improved HVAC system operates more efficiently by avoiding unit loading hopping and minimizing power consumption.