Method and system for heating auto-setback
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Solution Overview
Problem
Conventional HVAC systems lack the ability to autonomously determine optimal operating parameters when a space is unoccupied, leading to unnecessary energy consumption as they rely on user-input set-point temperatures and schedules, rather than adjusting based on actual occupancy and environmental conditions.
Innovation Solution
An HVAC system equipped with a controller that predicts temperatures during unoccupied times and adjusts operation accordingly, determining if the predicted temperature is below a set-point, and if so, operates the system for a calculated runtime to ensure the space reaches the desired temperature by the time it is occupied, thereby optimizing energy use without user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the HVAC system operates continuously to maintain set-point temperature, then the temperature comfort is improved, but the energy consumption increases
Solution Approach 1:
The system performs preliminary heating or cooling during unoccupied periods by predicting the temperature trajectory and determining if the space will reach the set-point temperature by occupancy time. This allows the system to operate only when necessary to meet future temperature requirements, rather than continuously maintaining set-point temperature, thereby reducing energy consumption while ensuring temperature comfort is achieved when needed.
2Use of energy by moving object
If the HVAC system shuts off during unoccupied time to save energy, then the energy consumption is reduced, but the temperature may deviate from set-point
Solution Approach 1:
The system uses predictive feedback by calculating the first predicted temperature during unoccupied time with the HVAC off, comparing it to the set-point temperature, and using this information to determine whether HVAC operation is necessary. This feedback mechanism allows the system to shut off during unoccupied periods when the predicted temperature will remain acceptable, saving energy while maintaining temperature stability when required.
3Device complexity
If the system uses simple thermostat with user-input schedules, then the device complexity is reduced, but the adaptability to actual conditions decreases
Solution Approach 1:
The system performs self-service by autonomously predicting temperature trajectories, determining occupancy status, calculating required HVAC runtime, and adjusting operation without user intervention. The controller automatically adapts to actual conditions by predicting whether the space will reach set-point temperature by occupancy time, eliminating the need for complex user-programmed schedules while maintaining high adaptability to real-time conditions.
Data Source
AI summary
A method of operating an HVAC system using a controller includes predicting a first predicted temperature of an enclosed space during an unoccupied time with the HVAC system off. The controller determines if the first predicted temperature is less than a set-point temperature. Responsive to a determination that the first predicted temperature is less than the set-point temperature, the controller predicts a second predicted temperature of the enclosed space if the HVAC system is operated for a first runtime. The controller determines if the second predicted temperature is less than the set-point temperature and, responsive to a determination that the second predicted temperature is not less than the set-point temperature, the controller operates the HVAC system for the first runtime.