HVAC Variable-Air-Volume Control Using Generic Electronic Thermostat

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Single-zone Variable-Air-Volume (VAV) HVAC systems cannot be controlled using generic controllers like electronic thermostat modules, requiring OEM-specific integrated controllers or Building Automation Systems controllers, limiting user flexibility and compatibility.

Innovation Solution

A method and system that utilize a controller to measure temperature, calculate temperature differences, and select operating modes for HVAC systems, allowing for flexible control and operation using a generic controller, enabling compatibility with various controllers and systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If VAV systems use OEM-specific integrated controllers or Building Automation Systems controllers, then precise temperature control and system reliability are improved, but device complexity and user operation difficulty increase

Engineering Contradiction:

Improvetemperature control precisionVSAvoidcontroller complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a communication interface as an intermediary layer between the simple electronic thermostat and the complex VAV system. This interface translates generic thermostat commands into VAV-specific control signals, enabling precise temperature control without requiring users to directly interact with complex VAV controllers. The intermediary handles the complexity internally while presenting a simple interface to the user.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If VAV systems use OEM-specific integrated controllers, then system reliability and temperature control are improved, but ease of operation and user flexibility deteriorate

Engineering Contradiction:

Improvesystem reliabilityVSAvoiduser operation ease

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent makes the electronic thermostat universal by enabling it to control multiple types of HVAC systems including VAV, conventional, and heat pump systems. The thermostat maintains its simple, familiar interface while internally adapting to different system types through communication protocols and control algorithms that work across various HVAC architectures, thus preserving ease of operation while ensuring reliable control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If VAV systems use Building Automation Systems controllers with communication protocols, then adaptability and control flexibility are improved, but device complexity increases

Engineering Contradiction:

Improvecontroller adaptabilityVSAvoidcontroller complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The communication interface acts as an intermediary that handles protocol translation and system adaptation internally. It converts simple temperature setpoint commands from the electronic thermostat into appropriate VAV control signals using communication protocols, thereby providing adaptability to different HVAC systems without exposing the user to protocol complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of operation

If generic electronic thermostat modules are used to control VAV systems, then ease of operation and cost are improved, but temperature control precision and system compatibility deteriorate

Engineering Contradiction:

Improvethermostat operation easeVSAvoidtemperature control precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The communication interface serves as an intermediary that receives simple temperature setpoint inputs from the electronic thermostat and translates them into precise VAV control commands. It calculates appropriate airflow adjustments and compressor operations based on the temperature differential, maintaining temperature control precision while preserving the simplicity of the electronic thermostat interface.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical/electrical connection methods with communication-based control. Instead of requiring hardwired connections to complex VAV controllers, the system uses communication protocols to transmit control signals, substituting physical complexity with digital communication that maintains precision while simplifying user interaction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10635060B2Systems and methods for variable control and operation of HVAC components

Publication Date: 2020.04.28 LENNOX IND INC

AI summary

A method of controlling operations of an HVAC system includes measuring temperature within an enclosed space, receiving a setpoint temperature within the enclosed space, calculating a temperature difference between the measured temperature and the received setpoint temperature, and determining whether the temperature difference between the measured temperature and the received setpoint temperature is greater than or equal to a first predetermined temperature differential value. If the temperature difference between the measured temperature and the received setpoint temperature is greater than or equal to the first predetermined temperature differential value, determining whether the temperature difference between the measured temperature and the received setpoint temperature is greater than or equal to a second predetermined temperature differential value. If the temperature difference between the measured temperature and the received setpoint temperature is less than the second predetermined temperature differential value, selecting a first operating mode of a plurality of operating modes of the HVAC system.