Thermophysical Property Measurements of Tetrabutylphosphonium Oxalate (TBPOx) Ionic Semiclathrate Hydrate as a Media for the Thermal Energy Storage System

Abstract

With increasing global power demand, thermal energy storage technology could play a role ensuring a sustainable energy supply in power generation from renewable energy sources and power demand concentration. Hydrates have high potential as phase change materials (PCMs) for the use as a thermal energy storage medium. To develop thermal energy storage technology using a hydrate-based material, further investigation of thermophysical properties and the selection of a suitable hydrate are required. Tetrabutylphosphonium oxalate (TBPOx) ionic semiclathrate hydrate contains oxalic acid in salt form, as a guest compound, which is classified as carboxylic acid group with low environmental impact. In the present study, the phase equilibrium temperature and the dissociation heat of TBPOx hydrate were measured. The highest equilibrium temperature of the solid hydrate formed was 9.4 • C at the mass fraction 0.35 of TBPOx in aqueous solution. The largest dissociation heat was 186.0 ± 0.5 kJ•kg −1 at the mass fraction of 0.35. Comparing with other PCMs with close phase equilibrium temperatures, TBPOx hydrate is superior in safety and sustainability. These results indicate that TBPOx hydrate would be suitable as the thermal storage medium for the general air conditioning systems.

Investigation of the thermodynamic properties of hydrates as cooling phase change materials for their implementation in electric vehicles

“…The enthalpy of hydrate decomposition has been measured by the same experimental method. 26,[32][33][34] The validity of the temperature rise rate was demonstrated by Yamauchi et al 36 To confirm the reproducibility of the heat flow rate curve and the dissociation enthalpy value, three measurements were carried out at each concentration. The measurements were performed with three different samples which were adjusted to the same concentration.…”

“…The following methods were used in previous studies, which reported the equilibrium temperature of other hydrates formed under atmospheric pressure. 26,[32][33][34] Approximately 25 g of aqueous piperazine solution was injected using a pipette at various mass fractions and was sealed in a glass tube with an inner volume of 70 cm 3 . The tubes were kept at 5 1C in a refrigerator for 24 hours to ensure the formation of piperazine hydrate.…”

“…35 This apparatus is the same as that used in previous studies. 26,[32][33][34]36 In this study, a stainless-steel test cell (100 cm 3 ) was used. Approximately 35 g of reagent was injected into the test cell using a dropper.…”

Functional Unit Construction for Heat Storage by Using Biomass-Based Composite

“…(Yu et al, 2020;Wu et al, 2021). The increasing energy shortage and environmental pollution bring an urgency to the improvement of energy storage efficiency and the reduction of greenhouse gas emissions (Huang et al, 2021a;Miyamoto et al, 2020). To solve the above problem, thermal energy storage technology is widely utilized to alleviate the mismatch between energy supply and demand to a certain extent, therefore improving the utilization rate of renewable energy (Lu et al, 2019a;Yang et al, 2019;Li et al, 2022).…”

Thermal Energy Storage Performance of Tetrabutylammonium Acrylate Hydrate as Phase Change Materials

“…Utilizing clathrate hydrate for a thermal energy storage medium has been proposed as a better idea than water or an ice-based medium [19][20][21][22][23]. Clathrate hydrates, ice-like compounds, are formed when some gases have contact with water or ice under high pressure and/or low temperature [24].…”