ABSTRACT

Oxalic acid dihydrate (OAD) which has the high initial phase transition enthalpy is a promising PCM for thermal energy storage (TES). However, large degradations of thermophysical properties over time have restricted further application of OAD. Cyclic stability of OAD, which means thermal cycling stability, needs to be improved to give full play to its potential for TES. In this paper, cyclic stability of OAD was determined by using ordinary aluminum pans and high pressure gold-plated pans in DSC measurement. In addition, PEG (with different molecular weights) was added to improve cyclic stability of OAD. Results show that the containers with good sealing performance and strong corrosion resistance are vital for the application of OAD. Meanwhile, adding 2.5% PEG 6000 gives better cyclic stability to OAD without affecting its melting temperature neither decreasing significantly its heat of fusion.

Compounds

#	Formula	Name
1	C2H6O6	ethanedioic acid dihydrate

Datasets

The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type	Compound-#	Property	Phase	Method	#Points
POMD	1	Normal melting temperature, K ; Crystal	Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	1	Normal melting temperature, K ; Crystal	Crystal Liquid Air at 1 atmosphere	DTA	1
POMD	1	Molar enthalpy of transition or fusion, kJ/mol ; Crystal	Crystal Liquid Air at 1 atmosphere	DSC	1
POMD	1	Molar enthalpy of transition or fusion, kJ/mol ; Crystal	Crystal Liquid Air at 1 atmosphere	DSC	1

Thermodynamics Research Center / ThermoML | Thermochimica Acta

Test and improvement of the cyclic stability of oxalic acid dihydrate for thermal energy storage

Han, L.[Lipeng], Xie, S.[Shaolei], Ma, G.[Guixiang], Sun, J.[Jinhe], Jia, Y.[Yongzhong], Jing, Y.[Yan]

ABSTRACT