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<p>An open system differential vacuum calorimeter was designed, constructed, and characterized for use in measuring heat flow associated with changes in non-equilibrium steady-state dynamical systems. While not unprecedented, these systems are new, and not generally available commercially. This system utilizes a pair of containers with an active experiment placed in one, and a reference experiment containing an equivalent thermal mass placed in the other; the reference container is used to reject common-mode heat perturbations that are primarily influenced via black-body radiation, since no convection occurs, and the conductive heat-transport path is minimized by design. Two different pairs of thermoelectric modules are used within the calorimeter design. A passive pair is used as heat-flux sensors, while an active pair is used in a feedback loop to create an isothermal reservoir. In addition to experimental containers and thermoelectric modules, the calorimeter is composed of three elements: heat-transfer plates, a cold plate, and a liquid-cooled heatsink to lift waste heat from the active thermoelectric modules. High vacuum is achieved using a turbomolecular pump where the mean-free path length in the resulting vacuum of less than 10<sup>–5</sup>&#xa0;torr is much larger than the calorimeter itself. The system has been used over an operating range of input and extracted heat ranging from 20&#xa0;mW up to 28&#xa0;W, reflecting an operating temperature range from 12 to 244&#xa0;°C, within 1% accuracy.</p>

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An open system differential vacuum calorimeter

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年6月9日

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  • Mitchell D. Kelley,
  • Madison Atwood,
  • Trevor Dardik,
  • Dennis van der Vliet,
  • Shelby Lacouture,
  • Jephthah Akene,
  • Samuel Adeosun,
  • Robert V. Duncan

摘要

An open system differential vacuum calorimeter was designed, constructed, and characterized for use in measuring heat flow associated with changes in non-equilibrium steady-state dynamical systems. While not unprecedented, these systems are new, and not generally available commercially. This system utilizes a pair of containers with an active experiment placed in one, and a reference experiment containing an equivalent thermal mass placed in the other; the reference container is used to reject common-mode heat perturbations that are primarily influenced via black-body radiation, since no convection occurs, and the conductive heat-transport path is minimized by design. Two different pairs of thermoelectric modules are used within the calorimeter design. A passive pair is used as heat-flux sensors, while an active pair is used in a feedback loop to create an isothermal reservoir. In addition to experimental containers and thermoelectric modules, the calorimeter is composed of three elements: heat-transfer plates, a cold plate, and a liquid-cooled heatsink to lift waste heat from the active thermoelectric modules. High vacuum is achieved using a turbomolecular pump where the mean-free path length in the resulting vacuum of less than 10–5 torr is much larger than the calorimeter itself. The system has been used over an operating range of input and extracted heat ranging from 20 mW up to 28 W, reflecting an operating temperature range from 12 to 244 °C, within 1% accuracy.