Solid-State Common-Wire Adapter for Smart Thermostat Power Delivery
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Solution Overview
Problem
Conventional thermostats lack a common wire, leading to reliability issues and increased energy consumption in HVAC systems, as smart communicating thermostats often rely on power stealing methods that cause unintended system activations and battery drain, resulting in comfort issues and energy inefficiencies.
Innovation Solution
A solid-state common-wire adapter using gate-sensitive TRIACs or FETs with a capacitor and internal load resistor to recreate a full AC waveform, allowing reliable power delivery to smart communicating thermostats without the need for additional wiring, thereby eliminating the requirement for a common wire and reducing energy waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If power stealing is used to provide power to smart communicating thermostats without a common wire, then the thermostat can operate without additional wiring, but the HVAC system experiences unintended activations and battery drain causing reliability issues
Solution Approach 1:
The patent introduces an intermediary device (power extension kit or common wire adapter) that mediates between the existing 4-wire HVAC system and the smart thermostat requiring a common wire. This intermediary provides the necessary common wire connection without requiring installation of a new wire through the building, thus maintaining installation simplicity while ensuring reliable power delivery and preventing the unintended activations associated with power stealing methods
2Reliability
If electro-mechanical devices are used to provide a common wire, then common wire functionality is achieved, but the devices are large and expensive increasing overall system cost
Solution Approach 1:
The patent replaces electro-mechanical common wire providing devices with solid-state electronic solutions. The solid-state common wire adapter uses electronic components rather than electro-mechanical relays or switches, resulting in a smaller, more reliable device with no moving parts. This substitution maintains the common wire functionality while significantly reducing device size, complexity, and cost
3Use of energy by moving object
If the heater ventilation fan operates at lower speed during heating, then energy consumption is reduced, but heat soak increases causing heat loss to the environment
Solution Approach 1:
The patent implements dynamic fan speed control that adjusts the heater ventilation fan speed based on real-time operating conditions. Rather than operating at a fixed low speed, the fan dynamically adjusts its speed to optimize the balance between energy consumption and heat delivery. This prevents excessive heat soak in the heat exchanger while still reducing energy consumption compared to continuous high-speed operation
4Use of energy by moving object
If the cooling ventilation fan operates only when the cool source is energized, then energy consumption is reduced, but cold water condensation is wasted causing increased operational time
Solution Approach 1:
The patent implements a delayed fan-off feature that keeps the cooling ventilation fan running for a period after the cool source (compressor) is turned off. This preliminary continuation of fan operation allows the system to utilize the cold air already circulated and the cold water in the condenser for additional cooling before the fan shuts down. This recovers cooling capacity that would otherwise be wasted, reducing the need for extended operational time
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides reliable and continuous power to smart communicating thermostats, enhancing customer comfort and safety while minimizing energy consumption and extending the operational life of HVAC systems by reducing waste heat and transformer load.
Implementation Method 1
A solid-state common-wire adapter using gate-sensitive TRIACs or FETs with a capacitor and internal load resistor to recreate a full AC waveform
Implementation Method 2
A solid-state common-wire adapter using gate-sensitive TRIACs or FETs with a capacitor and internal load resistor to recreate a full AC waveform
Implementation Method 3
minimizing energy consumption and extending the operational life of HVAC systems by reducing waste heat and transformer load
Data Source
AI summary
A solid-state common-wire adapter combines two Heating, Ventilating, Air Conditioning (HVAC) control signals on a single pre-existing wire to allow another pre-existing wire to be used as a common-wire to provide reliable power to a Smart Communicating Thermostat. The solid-state common-wire adapter may comprise a thermostat element with at least one diode and an HVAC element with at least one device selected from the group consisting of: a solid-state TRIode for Alternating Current (TRIAC), a capacitor, a microprocessor, a power supply, an optoisolator, and a load resistor. Smart Communicating Thermostats require continuous power for communicating with a wireless network, providing a Liquid Crystal Display (LCD) display, and controlling an HVAC system. Some Smart Communicating Thermostats use power stealing which is unreliable. The solid-state common-wire adapter is reliable, small, low-cost, and easy to install.