Materials-to-device design of hybrid metal-polymer heat exchanger tubes for low temperature waste heat recovery

Review of Scientific Instruments

Sinha

2021

Self Cite

Magnetostrictive transducers are commonly used as actuators, sonar transducers, and in remote non-destructive evaluation. Their use in wireless thermometry is relatively unexplored.Since magnetostriction-based sensors are passive, they could potentially enable long-term nearfield thermometry. While the temperature sensitivity of resonance frequency in magnetostrictive transducers has been reported in previous studies, the origin of the temperature sensitivity has however not been elucidated. Here, we identify material properties that determine temperature sensitivity, and identify ways to improve sensitivity as well as the detection technique. Using a combination of analytical and computational methods, we systematically identify the material properties that directly influence the temperature coefficient of resonance frequency (TCF). We first experimentally measure the shift in resonance frequency due to temperature changes in a Metglas strip to be 0.03%K -1 . Using insights from theory, we then experimentally demonstrate a 5-fold improvement to the TCF by using Terfenol in place of Metglas as the magnetostrictive sensor material. We further demonstrate an alternate temperature sensing technique that does not require measuring the resonance frequency, consequently reducing instrument complexity. This work provides a general framework to analyze magnetostrictive materials and the sensing scheme for near-field wireless thermometry.

Section: Discussionmentioning

confidence: 99%

Design and analysis of magnetostrictive sensors for wireless temperature sensing

Review of Scientific Instruments

Sinha

2021

Self Cite

“…(4)) using Figure 2. We use finite element simulations that were validated for interfacial resistance modeling in our previous work [40], [54], [61] and for modeling transients in the supplementary material. A nominal volumetric heat of 2.5 nW is assumed to be released per cell, which corresponds to a typical cell metabolism rate [41], [62].…”

Section: Revisiting the Effective Thermal Conductivity Approximationmentioning

confidence: 99%

Cellular Thermometry Considerations for Probing Biochemical Pathways

Sinha

2021

Cell Biochem Biophys

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Temperature is a fundamental thermodynamic property that can serve as a probe of biochemical reactions. Extracellular thermometry has previously been used to probe cancer metabolism and thermoregulation, with measured temperature changes of ~1-2 K in tissues, consistent with theoretical predictions. In contrast, previous intracellular thermometry studies remain disputed due to reports of >1 K intracellular temperature rises over 5 min or more that are inconsistent with theory. Thus, the origins of such anomalous temperature rises remain unclear. An improved quantitative understanding of intracellular thermometry is necessary to provide a clearer perspective for future measurements. Here, we develop a generalizable framework for modeling cellular heat diffusion over a range of subcellular-to-tissue length scales. Our model shows that local intracellular temperature changes reach measurable limits (> 0.1 K) only when exogenously stimulated. On the other hand, extracellular temperatures can be measurable (> 0.1 K) in tissues even from endogenous biochemical pathways. Using these insights, we provide a comprehensive approach to choosing an appropriate cellular thermometry technique by analyzing thermogenic reactions of different heat rates and time constants across length scales ranging from sub-cellular to tissues. Our work provides clarity on cellular heat diffusion modeling and on the required thermometry approach for probing thermogenic biochemical pathways.

“…For instance, the heat flux across batteries [3], [13], thermoelectric coolers [14], [15] and heat spreaders [16], [17] in electronics packaging are often limited by the thermal resistance of their interfaces, which are ~10 -5 -10 -3 m 2 KW -1 . Similarly, in composite heat recovery systems, the effective thermal conductivity and the profitability of heat recovery is dependent on the thermal interfacial resistance [6], in particular on metal-polymer TIR in the range 10 -5 -10 -3 m 2 KW -1 . Such metal-polymer interfaces, especially in electronics packaging [16] and batteries [3], often deteriorate over time due to cyclic loading, which increases the TIR and can even lead to thermal runaway [4], [18].…”

Section: Introductionmentioning

confidence: 99%

Intrinsic thermal interfacial resistance measurement in bonded metal–polymer foils

Review of Scientific Instruments

Man

Agrawal

et al. 2020

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Heat conduction through bonded metal-polymer interfaces often limits the overall heat transfer in electronics packaging, batteries, and heat recovery systems. To design the thermal circuit in such systems, it is essential to measure the thermal interfacial resistance (TIR) across ~1-100 μm junctions. Previously reported TIR of metal-polymer junctions utilize ASTM E1530-based twoblock systems that measure the TIR by applying pressure across the interface through external heating and cooling blocks. Here, we report a novel modification of the ASTM-E1530 technique that employs integrated heaters and sensors to provide an intrinsic TIR measurement of an adhesively bonded metal-polymer junction. We design the measurement technique using finite element simulations to either passively suppress or actively compensate the lateral heat diffusion through the polymer, which can minimize the systematic error to ≲5%. Through proof-of-concept experiments, we report the TIR of metal-polymer interfaces made from DuPont's Pyralux doubleside copper-clad laminates, commonly used in flexible printed circuit boards. Our TIR measurement errors are <10%. We highlight additional sources of errors due to non-idealities in the experiment and discuss possible ways to overcome them. Our measurement technique is also applicable to interfaces that are electrically insulating such as adhesively-joined metal-metal junctions and sputter-coated or welded metal-polymer junctions. Overall, the technique is capable of measuring TIR ≳10 -5 m 2 KW -1 in bonded metal-polymer foils, and can be tailored for in situ measurements in flexible electronics, circuit packaging, and other hybrid metal-polymer systems.