A new calorimetric technique for phase change materials and its application to alkane-based PCMs

Abstract

The correct determination of the phase transition behaviour of phase change materials (PCMs) is paramount for assessing their application potential. In this work, the merits of a novel calorimetric technique, Peltierelement-based adiabatic scanning calorimetry (pASC), for PCM characterisation are investigated, especially in comparison with the commonly-used differential scanning calorimeter (DSC). A comparative study of two alkanebased PCMs, the commercial mixture RT42 and the pure alkane tricosane (C23) with these two techniques shows that pASC provides data at much higher resolution than DSC, due to its operation in thermodynamic equilibrium. Specifically the rate-dependence and deformation that is inherent to DSC experiments is absent in pASC. In addition, the enthalpy of the PCM is directly obtained. pASC results easily conform to the accuracy limits that are proposed in literature for the transition temperature and storage capacity of PCMs.

CdSe/ZnS quantum dot fluorescence spectra shape-based thermometry via neural network reconstruction

“…The temperature of the plate was measured by both an Omega F3141 PT1000 RTD (measured by an HP-34401, with an uncertainty of 0.065 K, based on calibration inside of a furnace used in adiabatic scanning calorimetry 33 ) and an in-house welded Omega type T thermocouple (via HP-34970 A, with an uncertainty of 0.1 K, based on a similar calibration) to ensure that the ends of the fiber were near the same temperature, with their location shown in Figure 1. The temperature control of the plate was based on the PT1000 using a PID subroutine in Labview, which controlled the heating resistor voltage supplied by an Agilent E3631A power supply.…”

Potential new reference materials for caloric measurements on PCM

“…This size is similar to that of typical hf-DSC equipment. Recently, pASC has been used extensively for measuring reference materials like gallium [18] or biphenyl and phenyl salicylate [19], water and water-sodium chloride solutions [20], the n-alkanes C23 [21] and C26, C27, C28, C29, C30 [22], as well as the commercial PCM RT42 ( [21,23]).…”

Investigation of the electrocaloric effect in BaTiO3 multilayers by pASC calorimetry

“…As mentioned above, Peltier-element-based adiabatic scanning calorimetry (pASC) is a well-established method for thermal analysis, in which a constant power is applied to a sample, in particular for studying the enthalpy evolution throughout a phase transition while maintaining thermodynamic equilibrium and yielding rate independent results. In this work, a standard pASC measurement setup [15] was modified in order to apply an electric field to the sample for direct electrocaloric measurements under isothermal conditions. Measurements were carried out on a multilayer capacitor containing barium titanate (Model Y5V) purchased from AVX Company The sample size was 3.3 × 2.9 × 2.56 mm 3 with mass 91.14 mg.…”

“…Fitting with P = a ∆V + b yielded a = 6. 13 The main favorable feature of the employed calorimeter design is the highly precise measurement of the heat produced in the sample, by adequate control and measurement of the (typically zero) heat exchange with the environment [15,17,18]. In the used apparatus, the thermal contact with the environment is minimized by making use of long, thin coiled wires for the electrical connections to the platinum resistors and heating resistor on the measurement platform, and by maintaining vacuum in all compartments.…”

“…The present study addresses this need, proposing a genuine adiabatic calorimeter design that is intended to yield reliable direct measurements on electrocaloric materials. The design is based on a Peltier element based adiabatic scanning calorimeter [15]. In its standard mode of operation, a constant power P is supplied to the sample platform, while the temperature evolution is continuously monitored.…”