The melting behaviour of water and water–sodium chloride solutions studied by high-resolution Peltier-element-based adiabatic scanning calorimetry

Potential new reference materials for caloric measurements on PCM

“…Water, as already suggested by Archer [13], is thus Fig. 6 Results of pASC measurements on highly pure (Fisher) water (left), and comparison with water of different purities (right): Spa water and a diluted salt solution with 0.1388 mass% of NaCl Source: [20] Table 1 Water data from Leys et al [20] The transition temperatures were obtained from the intersection of the extrapolations of the h(T) data in the upper transition region and the higher temperature phase. The transition enthalpies were obtained following the procedure of "calculation of the molten fraction".…”

“…It poses no hazards, has a low vapor pressure, and is compatible with containers and air exposure (hygroscopic, oxidation…). The measurement of the property for Δ pc h shows a variation by composition < 1% (Fischer and Spa water) and ≤ 2% by uncertainty of the value (comparison of the values from [20] with those of [34]), for T pc a variation by composition < 0.2 °C and < 0.1 °C by uncertainty of the value. The presentation/communication of the property data includes the specification of the material (composition, preparation…), the value or value of the property including uncertainty, and also the measurement method used and a reference where further information is found.…”

“…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]).…”

“…E.g. based on the assumption of having a true ideal phase change, the peak width in c p (T) reflects a gradual change of phase such that the fraction of the shaded area of the peak on the left and right of a temperature gives the fraction of the phases; this is called the 1/F (extrapolation) method [20,36]. If the phase change is not ideal, it just reflects the fraction of the peak's enthalpy.…”

“…Leys et al [20] present pASC measurements (heating) of highly pure (Fisher) water (Fig. 6, left), and comparison with water of different purity (right): Spa water and a diluted salt solution with 0.1388 mass% of NaCl.…”