System and method for occupancy detection in split thermostat
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Solution Overview
Problem
Existing HVAC systems face challenges in accurately detecting occupancy, leading to false positive and false negative indications, which can result in inefficient energy usage and reduced user comfort.
Innovation Solution
A temperature control system that includes a thermostat with a processor and memory, along with remote auxiliary devices equipped with manually activated occupancy indicators and remote temperature sensors. This system allows users to actively indicate occupancy, which is then communicated to the thermostat to control the HVAC system effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If passive infrared (PIR) sensors are used to detect occupancy, then the system can automatically detect occupancy without user intervention, but the sensors become blind to stationary persons due to lack of movement
Solution Approach 1:
The patent introduces an occupancy indicator as an intermediary device that bridges the gap between automatic detection and reliable occupancy indication. The indicator is placed in the conditioned space and provides direct user input to confirm occupancy status, complementing the PIR sensor's automatic detection capability and resolving its blind spot issue for stationary persons.
Solution Approach 2:
The system implements feedback by having the occupancy indicator provide real-time occupancy status back to the thermostat. This feedback loop allows the thermostat to adjust its control strategy based on confirmed occupancy information, ensuring reliable operation even when automatic sensors fail to detect stationary occupants.
2Reliability
If ultrasonic or microwave sensors are used for occupancy detection, then the system can detect stationary occupants, but the sensors produce false positive and false negative indications
Solution Approach 1:
The patent merges multiple occupancy detection approaches by combining automatic sensors (PIR, ultrasonic, or microwave) with manual occupancy indicators. This hybrid system leverages the strengths of each method while compensating for their weaknesses, using the occupancy indicator to verify and correct false readings from automatic sensors.
Solution Approach 2:
The occupancy indicator provides feedback to validate or correct automatic sensor readings. When automatic sensors produce false positives or negatives, the manual indicator serves as a verification mechanism to establish the true occupancy status, thereby improving measurement precision.
3Ease of operation
If the thermostat is located in a specific conditioned space, then it can control that space effectively, but it cannot directly detect occupancy in other conditioned spaces
Solution Approach 1:
The patent segments the occupancy detection function by placing individual occupancy indicators in each conditioned space. Each indicator independently reports occupancy status of its local space to the thermostat, enabling the thermostat to gather occupancy information from multiple spaces without being physically present in each one.
Solution Approach 2:
The occupancy indicators act as intermediaries that collect occupancy information from various conditioned spaces and transmit it to the thermostat. This allows the thermostat to maintain effective control of its local space while also acquiring occupancy data from other spaces through these intermediary devices.
Data Source
AI summary
A method of operating a heating ventilation and air conditioning (HVAC) system by a thermostat to control an environmental parameter of a plurality of conditioned spaces is described. The method includes detecting a first value of the environmental parameter of the first conditioned space, the first value being detected by the thermostat, controlling the HVAC system based on the first value of the environmental parameter and a first setpoint for the environmental parameter, receiving, from a first occupancy indicator, a first indication of occupancy of a second conditioned space of the plurality of conditioned spaces, the first occupancy indicator being a human actuated occupancy indicator, and controlling the HVAC system based at least in part on the received first indication of occupancy of the second conditioned space.