Enthalpy Sensor Wire for Thermal Energy Metering

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Solution Overview

Problem

Conventional systems for thermal energy metering in solar hot water tanks are expensive, inaccurate, and difficult to install, as they rely on flow meters and temperature sensors, providing indirect and inefficient measurements of energy input.

Innovation Solution

The use of an enthalpy sensor with a sensor wire that changes resistance with temperature, coupled with a processing unit to determine temperature changes, allowing for accurate measurement of energy flows in hot water storage tanks, including solar hot water storage tanks, by covering the entire vertical height of the tank and compensating for temperature variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional flow meters and temperature sensors are used for thermal energy metering, then measurement capability is provided, but system cost increases and installation difficulty increases

Engineering Contradiction:
Improvethermal energy measurementVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the temperature sensing function with the flow measurement function into a single integrated sensor assembly. The sensor wire is positioned within the flow path structure, allowing simultaneous measurement of flow rate and temperature differential without requiring separate flow meters and temperature sensors, thereby reducing system complexity while maintaining measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sensor wire serves multiple functions: it acts as both the flow measurement element (through its positioning and resistance characteristics) and the temperature sensing element (through its electrical resistance temperature detection capability). This multi-functionality eliminates the need for separate dedicated flow meter and temperature sensor components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If conventional flow meters and temperature sensors are used for thermal energy metering, then measurement capability is provided, but installation difficulty increases

Engineering Contradiction:
Improvethermal energy measurementVSAvoidinstallation ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The sensor assembly is designed as a segmented, modular structure where the sensor wire can be independently positioned and installed within the flow path. This segmentation allows for easier installation compared to conventional systems that require installation of multiple separate components (flow meter, multiple temperature sensors), as the integrated design reduces the number of installation steps and potential error sources.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If conventional temperature sensor-pairs are used in the solar loop, then indirect energy measurement is provided, but measurement accuracy decreases

Engineering Contradiction:
Improvesystem simplicityVSAvoidenergy measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The sensor wire acts as an intermediary element that directly interacts with the flowing water to simultaneously capture flow rate and temperature information. This direct measurement approach through the intermediary sensor wire eliminates the need for indirect energy measurement calculations based on separate flow meter and temperature sensor data, thereby improving measurement accuracy while maintaining system simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution provides a cost-effective, accurate, and easy-to-install method for thermal energy metering, enabling precise calculation of energy changes in solar hot water systems, improving measurement accuracy and user understanding of energy performance and cost savings.

Implementation Method 1

a sensor wire according to claim 1

Methodology Applied
Scientific EffectResistive temperature sensing: Electrical Resistance

Implementation Method 2

determining temperature based on changes in the resistance of the sensor wire

Methodology Applied
Scientific EffectTemperature coefficient of resistance: Thermo-resistive Effect

Data Source

PatentEP3129723B1Thermal energy metering using an enthalpy sensor
Publication Date: 2020.05.27 AQUANTA INC
  • EP3129723B1 patent drawingFigure 1
  • EP3129723B1 patent drawingFigure 2
  • EP3129723B1 patent drawingFigure 3~5

AI summary

Apparatus and methods are provided for thermal energy metering by measuring the average temperature of fluid in a tank, such as a hot water storage tank. Average temperature is measured with an elongated temperature sensor wire that can span the vertical height of the tank. The sensor wire can be protected with a waterproofing jacket. The sensor wire can be coupled to a second substantially parallel wire. A processing unit measures temperature from changes in the resistance of the sensor wire and measures rates of change to allow the system to distinguish different sources of heat increase and/or decrease.