Thermostat with startup temperature estimation
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Solution Overview
Problem
Thermostats face challenges in accurately measuring ambient temperature due to unknown initial states and temperature errors caused by internal heating and varying airflow, leading to unreliable readings for the first hour of operation.
Innovation Solution
The thermostat employs a processing circuit with temperature sensors and uses Non-Linear Least Squares (NLSQ) and Kalman filter techniques to estimate and compensate for the unknown initial temperature state, accounting for heat rise and airflow, ensuring accurate temperature readings from startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thermostat is turned on with an unknown initial temperature state, then the thermostat can start operation immediately, but the temperature readings are unreliable for the first hour due to unknown initial state and internal heating
Solution Approach 1:
The system performs preliminary temperature estimation using a heat rise model before relying on direct sensor readings. By predicting the thermostat's internal temperature state based on ambient temperature and heat generation characteristics, the system compensates for the unknown initial state and internal heating effects, providing accurate temperature readings from startup without requiring a warm-up period
Solution Approach 2:
A temperature compensation mechanism acts as an intermediary between the raw temperature sensor readings and the final reported temperature. The compensation algorithm accounts for internal heating and airflow variations, correcting the sensor readings to provide accurate ambient temperature measurements even during the first hour of operation
2Measurement precision
If the thermostat uses internal temperature sensors, then the thermostat can measure temperature, but internal heating and varying airflow cause temperature errors
Solution Approach 1:
The system converts the harmful effect of internal heating into useful information. By modeling the heat rise characteristics and using them in temperature compensation calculations, the system actually uses the thermal signature of internal components to correct measurement errors, turning a source of inaccuracy into a calibration reference
Solution Approach 2:
The temperature compensation system continuously monitors sensor readings and compares them against the heat rise model predictions. This feedback loop allows the system to dynamically adjust for internal heating and airflow variations, maintaining accurate temperature measurements throughout operation
Data Source
AI summary
A thermostat is disclosed. The thermostat can include one or more temperature sensors configured to measure a plurality of temperature values within a building. The thermostat can include a processing circuit coupled to the one or more temperature sensors. The processing circuit can receive the plurality of measured temperature values from the one or more temperature sensors. The processing circuit can determine, based on a time invariant Non-Linear Least Squares (NLSQ) technique and the plurality of measured temperature values, a compensated temperature value within the building, wherein the compensated temperature value accounts for an unknown temperature state of the thermostat when the thermostat is turned on.