Networked Thermostat Setpoint Ramping for HVAC Cycling Efficiency
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Solution Overview
Problem
Standard programmable thermostats have a restrictive user interface, leading to sub-optimal energy savings due to limited ability to account for multiple variables and require frequent user input, and they rely on a fixed hysteresis zone that can result in inefficient HVAC cycling, while humans are insensitive to slow temperature changes, suggesting potential for energy savings through adaptive temperature ramping without compromising comfort.
Innovation Solution
A network-connected thermostat system that uses a server to log ambient and external data to apply an n-phase ramped setpoint algorithm, adjusting the average temperature over time based on user preferences and external conditions, allowing for automatic optimization of temperature settings without affecting perceived comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed hysteresis zone is used to control HVAC cycling, then the thermostat allows temperature to drift within a set range to prevent rapid cycling, but this results in inefficient HVAC operation and increased energy consumption
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed hysteresis zone to a dynamic, adaptive hysteresis zone that adjusts its width based on outdoor temperature conditions. The system calculates an optimal hysteresis width using a quadratic function of the temperature difference between indoor setpoint and outdoor temperature, allowing the control band to expand when outdoor conditions are extreme and contract when conditions are mild, thereby reducing unnecessary HVAC cycling and energy consumption while maintaining system stability
Solution Approach 2:
The patent implements parameter changes by modifying the hysteresis zone width as a variable parameter rather than a fixed value. The system dynamically adjusts the hysteresis parameter based on real-time temperature measurements and a calculated optimal width, enabling the thermostat to adapt its temperature band to current environmental conditions, which optimizes energy efficiency while preventing rapid HVAC cycling
2Extent of automation
If programmable thermostats are used to shift between multiple temperatures at different times, then automation is improved, but the restrictive user interface and limited variables result in sub-optimal energy savings
Solution Approach 1:
The patent applies self-service by enabling the thermostat to automatically calculate and adjust its own optimal hysteresis zone width based on outdoor temperature conditions without requiring user programming or intervention. The system uses embedded algorithms that compute the optimal temperature band dynamically, eliminating the need for users to program complex schedules while achieving superior energy savings compared to traditional programmable thermostats
Solution Approach 2:
The patent implements feedback by continuously monitoring outdoor temperature conditions and using this information to dynamically adjust the hysteresis zone width. The system measures the temperature difference between indoor setpoint and outdoor temperature, processes this feedback through a quadratic calculation, and adjusts the control band accordingly, creating a closed-loop system that automatically optimizes energy efficiency based on real-time environmental conditions
3Ease of operation
If the setpoint temperature is maintained constantly to maximize comfort, then occupant comfort is improved, but energy consumption increases as the setpoint diverges from the balance point
Solution Approach 1:
The patent applies dynamics by implementing a dynamic setpoint strategy that adjusts the temperature setpoint based on outdoor conditions and occupancy patterns. The system uses a quadratic function to calculate an optimal hysteresis zone that allows the setpoint to vary within a comfortable range while minimizing energy consumption, particularly during extreme outdoor temperature conditions or when occupancy is low
Data Source
AI summary
The invention comprises systems and methods for ramping setpoints on thermostats controlling HVAC systems. At least one thermostat is located inside a structure and is used to control an HVAC system in the structure. At least one remote processor is in communication with said thermostat and at least one database stores data reported by the thermostat. At least one processor compares the outside temperature at least one location and at least one point in time to information reported to the remote processor from the thermostat. The remote processor ramps the setpoint on the thermostat so as to reduce the average spread between inside temperature and outside temperature in order to reduce energy consumption with affecting comfort. The remote processor takes into account the effect of weather conditions and occupant preferences in determining whether and when to ramp setpoints.