PCM Thermal Storage State of Charge Measurement via Gas Flow
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Solution Overview
Problem
Existing Thermal Storage Systems (TSS) using Phase Change Materials (PCM) face challenges in accurately measuring the state of charge due to the need for significant pressure resistance and tightness in the tank design, and are limited to PCMs with sufficient volume variation during phase change, which not all materials exhibit.
Innovation Solution
A measuring device that detects the circulation of gas between a gas headspace and another volume, resulting from volume changes of the PCM, allowing for the measurement of the state of charge without requiring forced gas injection or significant pressure resistance, using sensors and processing means to convert these measurements into data representing the charge state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure variation measurement in gas headspace is used to evaluate charge level, then measurement can be performed, but tank requires significant pressure resistance and tightness which increases device complexity
Solution Approach 1:
The invention extracts the measurement function from the pressurized gas headspace environment and relocates it to the external environment. By measuring gas flow rate outside the tank through a flow meter, the system eliminates the need for the tank to withstand significant pressure variations, thereby reducing tank design complexity while maintaining measurement capability
Solution Approach 2:
The invention introduces a flow meter as an intermediary device that mediates between the PCM volume change and the measurement system. Instead of directly measuring pressure inside the tank, the flow meter measures the gas flow rate caused by PCM expansion/contraction, providing an indirect but simpler measurement approach that avoids pressure resistance requirements
2Measurement precision
If forced gas injection is used to measure charge level, then measurement can be performed, but additional equipment and energy consumption are required
Solution Approach 1:
The system utilizes the natural volume expansion and contraction of the PCM during phase change to drive gas flow through the flow meter. This self-service mechanism eliminates the need for external gas injection equipment, pumps, or energy input, as the PCM's own physical properties provide the driving force for measurement
Solution Approach 2:
The invention replaces the mechanical forced injection system with a passive flow measurement system. Instead of using pumps or pressure vessels to force gas through the measurement path, the system relies on the natural buoyancy and volume changes of the PCM to create gas flow, substituting active mechanical systems with passive physical phenomena
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 enables accurate measurement of the state of charge without the need for complex tank design and pressure resistance, and is applicable to a wider range of PCMs, providing continuous and precise monitoring of charging and discharging power and energy storage.
Implementation Method 1
volume variation of the PCM during its change of state
Implementation Method 2
volume expansion or contraction of the PCM
Implementation Method 3
measuring device that detects the circulation of gas between a gas headspace and another volume
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to Thermal Storage Systems (TSS) using Phase Change Materials (PCMs), and more particularly, to a measuring device 102 for measuring the state of charge of a TSS 100 comprising a reservoir 101 for containing a PCM 200 and a gas head 300. The measuring device includes at least one sensor 1021 configured to deliver a measurement signal of a parameter relating to gas flow between a first volume containing the gas head 300 and a second volume, the gas flow being a consequence of a volume change in the PCM intended to be contained in the reservoir, such that the measured parameter is representative of the TSS's charge level. The PCM TSS according to the invention notably eliminates the need to design a reservoir resistant to significant pressure variations in the gas head.