Variable Speed HVAC Control Using Single-Speed Thermostat Interface
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Solution Overview
Problem
HVAC systems with variable speed compressor technology require complex and costly communication protocols to control indoor and outdoor air temperatures, increasing system components and costs.
Innovation Solution
A method and system that uses a single-speed system controller, an interface device with a processor and temperature sensor, to determine temperature differentials and transmit signals to a variable speed HVAC component, allowing it to operate efficiently without needing to know the exact set point temperature, thereby reducing costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a proprietary communication protocol is used to control variable speed compressor, then temperature control capability is improved, but system complexity and cost increase
Solution Approach 1:
The patent introduces an intermediary device that translates between simple on/off signals from a single-speed controller and the temperature differential information needed by the variable speed compressor. This mediator converts basic conditioning signals into meaningful temperature-based control commands without requiring complex communication protocols between the controller and compressor.
Solution Approach 2:
The system enables the variable speed compressor to determine temperature differentials autonomously by providing it with the necessary temperature information and control logic. The compressor uses local temperature sensors and embedded algorithms to calculate temperature differentials and adjust its speed accordingly, eliminating the need for external controllers to perform complex temperature management.
2Measurement precision
If a proprietary communication protocol is used to control variable speed compressor, then temperature control capability is improved, but system cost increases
Solution Approach 1:
The patent employs inexpensive temperature sensors and simple on/off signaling mechanisms instead of costly proprietary communication modules. The system uses basic, readily available components that can be easily manufactured and replaced, avoiding the need for expensive specialized communication hardware while achieving effective temperature control.
Solution Approach 2:
The intermediary translation layer enables the use of simple, low-cost signaling methods while achieving sophisticated temperature control. By converting basic on/off signals into temperature differential commands at the compressor level, the system avoids the need for expensive bidirectional communication protocols throughout the entire system.
3Use of energy by moving object
If variable speed compressor is used, then energy efficiency is improved, but control complexity increases
Solution Approach 1:
The patent controls the variable speed compressor by changing a single key parameter - the temperature differential - rather than managing multiple complex control variables. The compressor speed is adjusted based on this single parameter, which directly reflects the heating or cooling demand, simplifying the control strategy while maintaining energy efficiency.
Solution Approach 2:
The system implements a feedback mechanism where temperature sensors continuously monitor the indoor environment, and the variable speed compressor adjusts its operation based on the measured temperature differential. This closed-loop feedback ensures energy efficient operation by matching compressor output to actual thermal demand without requiring complex predictive algorithms.
Data Source
AI summary
A system and method of operating an HVAC system, the HVAC system including a HVAC unit including a variable speed HVAC component in communication with a unit controller, an interface device in communication with the unit controller, and a single-speed system controller in communication with the interface device, the method including operating the interface device to receive a first conditioning signal from the system controller, operating the interface device to determine a temperature differential when the first conditioning signal is received, operating the interface device to transmit the temperature differential to the unit controller, operating the unit controller to transmit a speed signal based on the temperature differential, operating the interface device to receive a second conditioning signal, and operating the interface device to update the at least one set point estimate when second conditioning signal is received.