HVAC Setpoint Modulation for Demand Response Energy Reduction
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Solution Overview
Problem
HVAC systems consume a significant amount of energy, and existing demand response schemes often disregard user preferences for temperature and humidity, leading to inefficient energy reduction strategies.
Innovation Solution
Implementing setpoint adjustment-based duty cycling techniques that modulate the thermostat setting between a base and an offset or fixed value to reduce energy consumption during demand response events, allowing the HVAC system to operate within acceptable comfort levels while minimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the HVAC system is regularly shut off to reduce energy consumption, then energy consumption is reduced, but user preferences with respect to temperature, humidity, and airflow are not taken into account
Solution Approach 1:
The patent implements dynamic duty cycling that adjusts the HVAC system operation based on real-time conditions. The controller dynamically modifies duty cycle parameters (on/off timing, duration) based on user preferences, outdoor conditions, and indoor environmental sensors, allowing the system to adapt between energy savings and comfort requirements rather than using fixed shutdown schedules
Solution Approach 2:
The system changes operational parameters by adjusting temperature setpoints, humidity setpoints, and airflow rates during duty cycling events. Instead of simple on/off control, the controller modifies these parameters to achieve energy reduction while maintaining acceptable comfort levels, such as allowing temperature to drift within a predefined comfort range during off-periods
2Ease of operation
If the HVAC system operates continuously to maintain user comfort preferences, then user preferences are satisfied, but energy consumption increases
Solution Approach 1:
The patent implements periodic duty cycling where the HVAC system alternates between active and inactive periods. During active periods, the system operates to maintain or restore comfortable conditions; during inactive periods, it shuts off to save energy. The timing, duration, and intensity of these periodic cycles are optimized based on thermal mass, outdoor conditions, and user comfort thresholds
Solution Approach 2:
Instead of continuous full-capacity operation, the system applies partial action by operating at reduced capacity or for reduced duration during duty cycling events. The controller allows temperature and humidity to drift partially away from ideal setpoints within acceptable comfort ranges, achieving energy savings while maintaining satisfactory comfort levels
3Loss of energy
If demand response schemes shut off HVAC components without regard to thermostat controller, then energy consumption is reduced during peak demand, but the system does not take into account user preferences
Solution Approach 1:
The patent incorporates multiple feedback mechanisms including indoor temperature sensors, humidity sensors, and user preference inputs that continuously inform the duty cycling controller. This feedback allows the system to adjust duty cycle timing and intensity to prevent comfort violations while achieving energy reduction goals during demand response events
Solution Approach 2:
The system performs preliminary actions by pre-cooling or pre-heating spaces before anticipated duty cycling off-periods, and by pre-adjusting setpoints based on forecasted outdoor conditions. This allows the HVAC system to be shut off during peak demand periods while thermal mass and pre-established conditions maintain acceptable comfort levels
Data Source
AI summary
A facility for performing setpoint adjustment-based duty cycling techniques by adjusting the setpoint of a device or component is described. The facility reduces energy consumption for a system, such as an HVAC system, or device by adjusting or modulating an associated setpoint or temperature setting. The facility modulates the setpoint between a base setpoint value and another setpoint value based on a mode of the system. When the system is in a cooling mode, the facility modulates the temperature between the base setpoint value and a higher setpoint value. When the system is in heating mode, the facility modulates the temperature between the base setpoint value and a lower setpoint value. The facility may modulate the setpoint between the two setpoint values based on an offset value or a fixed setpoint value.