Boiler Oxygen Sensing for Low-Cost Combustion Feedback Control

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Solution Overview

Problem

Existing water heating systems are inefficient and unable to effectively and cost-efficiently monitor the amount of oxygen in products of combustion, relying on expensive NDIR sensors.

Innovation Solution

A water heating system with a combustion chamber, burner, oxygen sensor, and control unit that detects oxygen levels in the combustion products, allowing for feedback control to optimize combustion and heat water efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If NDIR sensors are used to monitor oxygen levels in combustion products, then measurement precision is improved, but device cost increases significantly

Engineering Contradiction:
Improveoxygen level monitoring accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive NDIR sensors with a more affordable oxygen sensor that uses a solid electrolyte and electrochemical cell. This cheaper sensor provides sufficient measurement precision for combustion optimization while dramatically reducing system cost, making the technology economically viable for widespread implementation.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the measurement approach by using a solid electrolyte-based electrochemical sensor instead of infrared spectroscopy. This parameter change in sensing technology achieves acceptable oxygen level monitoring precision at a fraction of the cost of NDIR sensors.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If feedback control is implemented using oxygen sensor data, then energy efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidcontrol system complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where the oxygen sensor continuously monitors combustion products and sends signals to the control unit. The control unit adjusts the air-to-fuel ratio based on this feedback, optimizing combustion efficiency and reducing energy loss while maintaining manageable system complexity through automated control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs self-optimization of combustion parameters through automated feedback control. The control unit independently adjusts operational parameters based on oxygen sensor readings, eliminating the need for manual intervention and simplifying operation while improving energy efficiency.

Inventive Principle:
Principle #25Self-service

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 system effectively monitors and controls oxygen levels in the combustion process, enhancing efficiency and reducing costs by using a cost-effective oxygen sensor, similar to the Bosch LSU 4.9 wideband sensor, to optimize water heating performance.

Implementation Method 1

An oxygen sensor is coupled to the combustion chamber and positioned within the combustion chamber to detect an amount of oxygen remaining in the products of combustion

Methodology Applied
Scientific EffectElectrochemical sensing:

Implementation Method 2

A heat exchanger system is coupled to the combustion chamber to heat water in the heat exchanger with the products of combustion

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

The burner causes combustion of gas to create products of combustion

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP2745052B1Water heating system with oxygen sensor
Publication Date: 2019.01.09 AERCO INTERNATIONAL INC
  • EP2745052B1 patent drawingFigure 1
  • EP2745052B1 patent drawingFigure 2
  • EP2745052B1 patent drawingFigure 3

AI summary

Water heating system and method including a boiler, a combustion chamber, and a burner housed inside the chamber. A conduit fluidly coupled to the combustion chamber to channel gas into the chamber wherein the burner causes combustion of gas. An oxygen sensor is coupled to the chamber and positioned within the chamber to detect an amount of oxygen in the products of combustion. The oxygen sensor outputs data representative of the amount to a control unit. The control unit controls the feedback control of the water heating system and wherein the combustion of the gas in the chamber is controllable by the control unit at least based on the data. A heat exchanger system is coupled to the chamber to heat water in the heat exchanger with the products. At least one flue coupled to the heat exchanger system to channel products out of the heat exchanger system.