Water Heater Thermal Quantity Estimation Using Stratified Tank Model

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Solution Overview

Problem

Existing methods for estimating thermal quantities in water heaters are invasive and only applicable to new systems, requiring physical modifications and multiple sensors, which limits their use in existing equipment and accuracy due to the assumption of uniform temperature in storage tanks.

Innovation Solution

A method that estimates thermal quantities in water heaters by determining the final volumes and temperatures of tank parts based on operating regimes, energy consumption, and flow measurements, allowing for precise control without substantial modifications to existing systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple temperature sensors and capillary tubes are installed in the tank to measure thermal quantities, then measurement precision is improved, but device complexity and ease of manufacture deteriorate due to invasive modifications

Engineering Contradiction:
Improvethermal quantity estimation accuracyVSAvoidsystem modification complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses electrical consumption data as a proxy copy for thermal energy input, avoiding direct thermal measurement. Instead of installing temperature sensors throughout the tank, the system copies the thermal state information from electrical consumption records, combined with a simplified thermal model, to estimate thermal quantities non-invasively

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical sensor-based measurement system with an electrical/data-based estimation system. Instead of physically measuring temperature at multiple points, the system uses electrical consumption data processed through algorithms to infer thermal quantities, substituting physical measurement with computational estimation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a simplified single-temperature model is used for the tank, then ease of operation is improved, but measurement precision deteriorates due to temperature stratification assumptions

Engineering Contradiction:
Improvesystem operation simplicityVSAvoidthermal quantity estimation accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent divides the water tank into multiple vertical zones (upper, middle, lower portions) that can have different temperature characteristics. This segmentation allows the model to account for temperature stratification without requiring complex multi-sensor systems, balancing simplicity with accuracy by creating discrete thermal regions

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If existing water heaters are used without modification, then ease of manufacture and adaptability are improved, but measurement precision deteriorates due to lack of direct thermal measurements

Engineering Contradiction:
Improveapplicability to existing systemsVSAvoidthermal quantity estimation accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent enables existing water heaters to self-report their thermal state through their existing electrical consumption data and basic sensors. The system uses data already generated by the heater's operation (electrical consumption, basic temperature readings) to estimate thermal quantities, allowing the existing system to serve the measurement function without external modification

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

This method provides a non-invasive, accurate estimation of thermal quantities, enabling better energy optimization and adaptation to renewable energy variability while maintaining user comfort, and can be applied to existing water heaters without physical modifications.

Implementation Method 1

An intermediate part in thermal exchange with a device for heating the water in the tank, the device comprising heating means supplied by an electrical network

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The water inlet and/or the water outlet being equipped with a flow sensor measuring a flow rate of withdrawn water

Methodology Applied
Scientific EffectFlow measurement:

Implementation Method 3

An intermediate part in thermal exchange with a device for heating the water in the tank

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

water heater type system

Methodology Applied
Scientific EffectThermal convection: Convection

Data Source

PatentEP3101366B1Method for estimating a physical magnitude of a water heater water tank
Publication Date: 2019.06.26 ELECTRICITE DE FRANCE
  • EP3101366B1 patent drawingFigure 1a
  • EP3101366B1 patent drawingFigure 1b
  • EP3101366B1 patent drawingFigure 1c

AI summary

The invention relates to a method for estimating a thermal quantity of a water tank (10), the water tank (10) extending along a substantially vertical axis and having: - an intermediate part (P2 ) in heat exchange with a device (11) for heating the water in the tank (10); - A lower part (P1) having a water inlet (E); - An upper part (P3) having a water outlet (S); The water inlet (E) and/or the water outlet (S) being equipped with a flow sensor (21, 22) measuring a flow rate of withdrawn water; The method being characterized in that it comprises the implementation by data processing means (30) connected to said flow sensor (21, 22), of steps of: (a) Determination of an operating regime ; (b) From an initial volume (V2i) of the intermediate part (P2) and initial temperatures (T1i, T2i, T3i) of the parts (P1, P2, P3) of the reservoir (10), determination of a final volume (V2f) of the intermediate part (P2) and final temperatures (T1f, T2f, T3f) of the parts (P1, P2, P3) of the tank (10); (c) Estimation of said thermal quantity of the water tank (10) as a function of the final temperatures and volumes (T1f, T2f, T3f, V1f, V2f, V3f) of the parts (P1, P2, P3) of the tank (10) .