Occupancy Sensor Network for HVAC Auto-Away Energy Control
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Solution Overview
Problem
Commercial HVAC systems in buildings face challenges in efficiently managing energy consumption, as they often continue to operate even when spaces are unoccupied, leading to increased energy costs.
Innovation Solution
A networked smart lighting system with integrated occupancy sensors is used to control thermostats, enabling an "auto-away" feature that turns off heating or cooling units when no occupancy is sensed, thereby reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If HVAC systems operate continuously to maintain temperature, then temperature stability is improved, but energy consumption increases
Solution Approach 1:
The system performs preliminary actions by pre-cooling or pre-heating spaces before occupancy is expected, and maintains temperature only in occupied zones. The occupancy detection system anticipates when spaces will be needed and prepares them in advance, rather than continuously maintaining all spaces regardless of actual need.
Solution Approach 2:
The system dynamically adjusts HVAC operation based on real-time occupancy data from sensors throughout the building. Temperature setpoints, fan speeds, and system activation are continuously modified according to actual occupancy patterns, transforming the static continuous-operation model into a dynamic responsive system.
2Extent of automation
If occupancy sensors are integrated into the lighting network, then automation capability is improved, but device complexity increases
Solution Approach 1:
The patent makes the existing lighting network universal by enabling it to perform multiple functions: traditional lighting control plus occupancy detection and HVAC coordination. Rather than creating a separate dedicated HVAC control system, the lighting infrastructure is enhanced to serve both purposes, reducing overall system complexity.
Solution Approach 2:
The control server acts as an intermediary that receives occupancy data from the lighting network and translates it into appropriate HVAC control signals. This mediator layer integrates the lighting and HVAC systems without requiring direct complex interactions between them, simplifying the overall architecture.
3Productivity
If existing thermostat systems are modified to integrate with occupancy sensors, then energy control capability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent extracts the occupancy detection and control logic functions from the thermostat itself and places them in the existing lighting network and control server. This extraction allows the thermostat to remain a simple temperature-control device while the complex occupancy-based control intelligence resides elsewhere in the lighting infrastructure.
Solution Approach 2:
The system uses the existing lighting network infrastructure as a template or model for HVAC control. By copying the successful deployment pattern of occupancy sensors in lighting systems and applying the same approach to HVAC control, the patent avoids the need to manufacture entirely new thermostat devices with integrated sensors.
Data Source
AI summary
A system of networked occupancy sensors and a thermostat that is controlled using data from the sensors. In a data network of occupancy sensors, the sensors (i) sense occupancy in a first space, such as a room within a building, and (ii) transmit data packets. Each of the data packets comprises an indication whose value is based in part on whether occupancy is sensed or not in the first space. The thermostat is situated in the first space and provides a control signal on an output line for controlling heating, ventilation, and air conditioning (HVAC), based on the temperature sensed by the thermostat. A controller unit comprises (i) a radio transceiver, capable of receiving the data packets, and (ii) a processor. The processor modifies the control signal on the output line of the thermostat, based in part on the value of the indication in the packets from the occupancy sensors.