Cold Plate Differential Calorimetry for Accurate Open-System Heat Flux
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Solution Overview
Problem
Existing calorimeters are inadequate for measuring heat and power in open systems, as they cannot account for continuous heat or mass exchange, are expensive, and are not suitable for complex or large samples, limiting their practicality and accuracy.
Innovation Solution
An open system cold plate differential calorimeter using a solid-state thermoelectric unit as a heat reservoir, with calibrated thermal flux sensors and common mode rejection to measure heat flux, allowing for precise energy and power measurements in systems that exchange mass or heat with the environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If closed system calorimeters (bomb type) are used to measure heat flux, then measurement precision is improved, but adaptability to open systems deteriorates
Solution Approach 1:
The patent creates a reference cell that copies the thermal characteristics of the sample cell, allowing environmental effects to be measured and subtracted. This enables accurate open system measurements by replicating the thermal environment in a controlled reference chamber with identical thermal pathways.
Solution Approach 2:
The patent introduces a differential measurement system that acts as an intermediary between the sample and the measurement instrument. By measuring the difference between sample and reference cells, the system eliminates the need for perfect thermal isolation while maintaining measurement accuracy.
2Measurement precision
If closed system calorimeters are used, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines the sample measurement and environmental reference measurements into a single integrated differential system. The sample cell and reference cell share common thermal pathways and measurement electronics, reducing overall system complexity while maintaining accuracy.
Solution Approach 2:
The differential measurement system serves multiple functions: it measures sample heat flux, characterizes environmental effects, and provides calibration reference all within a single system architecture, reducing the need for separate specialized equipment.
3Measurement precision
If closed system calorimeters are used, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent uses inexpensive, easily manufactured components for both the sample and reference cells, such as simple aluminum blocks with embedded thermocouples. These cells can be easily replaced or reconfigured, avoiding the need for expensive custom-built equipment while maintaining measurement precision.
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
Enables accurate measurement of energy and power in open systems by canceling environmental temperature changes, providing precise measurements from a few milliwatts to several watts, immune to ambient temperature variations.
Implementation Method 1
a solid-state thermoelectric unit to act as a very precisely electronically controlled heat reservoir
Implementation Method 2
Heat flux between the active vessel and the thermal reservoir is measured by a first heat flux detector and heat flux between the passive vessel and the thermal reservoir is measured by a second heat flux detector
Data Source
AI summary
An open calorimetry system comprising an active vessel, a passive vessel, and a first and second heat flux detector in thermal communication with the active vessel and passive vessel respectively. A thermal reservoir is connected to the first heat flux detector and the second heat flux detector, wherein data from the heat flux detectors is used in a differential analysis resulting in an energy measurement of an article in the active vessel.