Fan Coil Thermostat Activity Sensing for Occupancy Setback
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Solution Overview
Problem
Fan coil systems in buildings consume significant energy, especially in unoccupied rooms, as existing thermostats lack the ability to automatically adjust temperature settings to energy-saving levels when spaces are unoccupied.
Innovation Solution
A fan coil thermostat with a controller implementing a control algorithm and a timer that allows for an unoccupied temperature setting, which can be overridden by user input, automatically reverts to this setting after a predetermined time or based on occupancy indicators, optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the thermostat maintains comfort temperature continuously, then occupant comfort is improved, but energy consumption increases
Solution Approach 1:
The thermostat dynamically adjusts the temperature setpoint based on detected occupancy status. When occupancy is detected, it maintains comfort temperature; when unoccupied, it transitions to energy-saving setback temperature, making the system adaptive rather than static
Solution Approach 2:
The system uses occupancy sensors to detect whether the space is occupied or unoccupied, providing feedback to the controller which then adjusts the temperature setpoint accordingly, creating a closed-loop control system that responds to actual conditions
2Use of energy by moving object
If the thermostat uses setback temperature for unoccupied rooms, then energy savings are improved, but occupant comfort deteriorates when rooms are reoccupied
Solution Approach 1:
The thermostat performs preliminary heating or cooling when occupancy is detected after a setback period, pre-conditioning the space before occupants arrive, so that comfort is restored without requiring excessive energy input at the moment of reoccupation
3Use of energy by moving object
If the thermostat automatically adjusts temperature based on occupancy, then energy efficiency is improved, but device complexity increases
Solution Approach 1:
The thermostat integrates multiple functions into a single device: occupancy detection, temperature sensing, timer functionality, and control algorithm processing, allowing it to perform automatic temperature adjustment without requiring separate dedicated devices for each function
Data Source
AI summary
Fan coil thermostats can provide energy savings by, for example, not unnecessarily heating and/or cooling an unoccupied room or other space. Fan coil systems employing such a fan coil thermostat may be more energy efficient. A fan coil system may include a fan coil that is configured for fluid communication with a source of heated fluid and/or a source of cooled fluid, a valve that controls fluid flow through the fan coil, a fan that blows air across the fan coil and a fan coil thermostat. The fan coil thermostat may include a controller that implements a control algorithm that may include an unoccupied temperature setting. The controller may be programmed to permit a user to enter a user-chosen temperature setting. In response, the controller may initiate a timer, and may automatically return to the unoccupied temperature setting once the timer has expired.