Remote HVAC Control with Separate Heat and Cool Setpoints
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Solution Overview
Problem
HVAC systems with single or common temperature setpoints for both heat and cool modes face inefficiencies when used with programmable schedules, leading to unnecessary activation of heating or cooling during inappropriate seasons, which reduces overall energy efficiency.
Innovation Solution
A remote programmable thermostat with a programmable schedule and auto changeover mode sends input signals to an onboard HVAC controller, allowing for separate heating and cooling setpoints with a dead band to prevent unnecessary mode switching, enabling the HVAC system to operate efficiently by activating heating when below the setpoint and cooling when above, while remaining standby during a dead band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a single common temperature setpoint is used for both heating and cooling modes in auto changeover mode, then the system can automatically switch between heating and cooling modes, but the system may incorrectly activate heating during cooling season or cooling during heating season when setback temperatures are applied, reducing energy efficiency
Solution Approach 1:
The patent segments the temperature setpoint control into separate heating setpoint and cooling setpoint values. Instead of using a single common setpoint for both modes, the system now maintains distinct setpoints for heating and cooling operations, allowing independent optimization of each mode's temperature control logic.
Solution Approach 2:
The patent applies different temperature setpoint qualities to different operational contexts. The heating setpoint and cooling setpoint have different characteristic values and adjustment rules appropriate to their respective seasonal contexts, rather than forcing a single setpoint value to serve both purposes.
2Use of energy by stationary object
If setback temperatures are applied during unoccupied periods, then energy savings can be achieved, but the single setpoint auto changeover logic may command incorrect mode activation based on the setback temperature direction
Solution Approach 1:
The patent implements dynamic setpoint selection based on operational context. The system dynamically adjusts which setpoint (heating or cooling) is active based on the season, occupancy status, and current temperature conditions, rather than relying on a static single setpoint that can lead to incorrect mode activation.
Solution Approach 2:
The patent incorporates feedback mechanisms that monitor both the setpoint temperature and the actual seasonal context to determine appropriate mode activation. The system uses feedback from temperature sensors and seasonal information to verify that mode activation aligns with current environmental conditions, preventing incorrect heating or cooling activation.
Data Source
AI summary
An HVAC system includes an HVAC unit having a cooling mode and a heating mode for conditioning the air in an inside space, and a programmable thermostat located remotely from the HVAC unit. The HVAC unit may have an onboard controller configured to control when the HVAC unit is in the cooling mode or heating mode, and whether the HVAC unit is activated or not. In some cases, the onboard controller of the HVAC unit may use a common temperature setpoint when controlling in the cooling mode and the heating mode. The programmable thermostat may have a programmable schedule with a plurality of time periods, where each time period has a heating setpoint and a cooling setpoint separated by a dead band. The onboard controller of the HVAC unit may be configured to accept input signals from the remotely located thermostat. The remotely located thermostat may send one or more input signals to the onboard controller of the HVAC unit in accordance with the programmable schedule, where the one or more input signals cause the onboard controller of the HVAC unit to set the HVAC unit to a particular one of the cooling mode and the heating mode, and to activate the HVAC unit so as to condition the air in the inside space in the particular one of the cooling mode and the heating mode.