Abstract Energy crisis is a major challenge in the current world. Latent heat thermal energy storage (LHTES) systems are known as equipment with promising performance by which thermal energy can be recovered. In the present study a comprehensive theoretical and experimental investigation is performed on a LHTES system containing PEG1000 as phase change material (PCM). Discussed topics can be categorized in three parts. At first, a one dimensional mathematical model is introduced for a heat exchanger containing flat slabs of PCM. To consider the latent heat of phase change, effective heat capacity is used in the model. Secondly, through eight experiments designed by using factorial method, effects of inlet air velocity and temperature on the outlet stream is investigated. The results proved that having a determined temperature difference between inlet air and the PCM in both hot and cold cycles can enhance the efficiency. Finally, the feasible applications of a LHTES system for controlling the temperature swing in a greenhouse is studied numerically and the results are compared with experimental values. As a result, by using this passive coolant system diurnal internal temperature can be reduced for 10 °C.

Phase-change material

Evaporative cooler

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Citations (3)

Triacylglyceride Thermal Cracking: Pathways to Cyclic Hydrocarbons

Energy & Fuels (2011)

Alena Kubátová Jana Šťávová Wayne Seames Yan Luo Seyed Mojtaba Sadrameli

Thermal cracking of triacylglyceride (TG) oils results in complex mixtures, containing nearly 20% cyclic hydrocarbons, which can be further processed into middle-distillate transportation fuels and byproduct chemicals. The occurrence patterns of cyclic products obtained via the thermal cracking of several TG feedstocks, such as canola and soybean oils, as well as triolein and tristearin (conducted at 430–440 °C in the absence of catalysts under vacuum), were investigated to probe possible formation mechanisms. Detailed gas chromatographic characterization furnished full molar homology/molecular size and partial isomeric profiles for cyclopentanes, cyclopentenes, cyclohexanes, cyclohexenes, aromatics, and polycyclic aromatic hydrocarbons (PAHs). It was found that the data were inconsistent with previously proposed mechanisms involving the Diels–Alder reaction as a single pathway. An alternate mechanism was proposed and supported with experimental evidence based on the intramolecular cyclization of alkenyl and alkadienyl radicals formed as a result of TG cracking. The product homology profiles corroborate the proposed mechanism and show the depletion of medium-size alkenes coupled with the accumulation of corresponding monocyclic hydrocarbons (those with the matching number of carbon atoms). Similarly, the product mixtures were depleted of long-chain alkyl-substituted monocyclic hydrocarbons because of the formation of the corresponding PAHs as long as sufficient time is available. Entropy appears to determine the type and size of cyclic hydrocarbons formed.

Alkane

Triolein

Cyclopentanes

Benzothiophene

10.1021/ef200953d

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Citations (81)

Preparation of Macro Encapsulated Phase Change Materials for High Temperature Energy Storage Applications

The minerals, metals & materials series (2020)

Seyed Mojtaba Sadrameli Sajad Soleimanpour

Phase-change material

Thermal energy