Views:266 Author:Site Editor Publish Time: 2020-07-17 Origin:Site
The ceaselessly increase in the depletion of fossil fuels and greenhouse gas emissions, as well as the ever-increasing energy shortages and global warming, has been widely discussed among the world. People have reached a consensus that improving energy utilization efficiency is the most effective strategies in terms of energy conservation and environmental protection. The consideration of utilization of thermal energy storage (TES) has been paid attention to phase change materials (PCMs) that have the intrinsic capacity of absorbing and releasing abundant heat during their phase transition process. But a leakage problem during the solid-liquid phase change process is the obstacle of its practical application. Among much approaches have been used to solve the leakage problem, tremendous interest has been focused in PEG based organic PCMs due to its remarkable merits of relative high phase enthalpy and suitable phase change temperature, good chemical stability, nontoxicity, and good biocompatibility.
As we know, integration of LAL particle into PCMs to synthesize PEG based self-luminous SSPCMs for both thermal and light energy storage, have not been reported. So in this work, we prepared a novel self-luminous SSPCMs via incorporating the LAL particle into PEG based SSPCMs for both thermal and light energy storage.
The shape-stability performance of self-luminous SSPCMs was conducted by the leakage test and the results of the leakage test were displayed by digital photos. It can confirm that the self-luminous SSPCMs have excellent shape-stability performance due to the network structure because of the stability of chemical bonds.
From the perspective of applicable phase change temperature and high latent heat, phase change performances are of vital importance for applications. This result was contributed to the high restriction of chemical effects, leading the rearrangement and orientation of PEG chains in self-luminous SSPCMs are hindered by the introduction of covalent bonds with amorphous units, which weakened crystallite size and crystallization ability of PEG4K.
Luminescence repeatability of self-luminous SSPCMs is also a vital factor because of the consecutive alternation of day and night for the practical utilization. The luminescence repeatability of these self-luminous SSPCMs was conducted by storing-releasing light energy test for 50 cycles. It demonstrated that the self-luminous SSPCMs have outstanding luminescence repeatability, which is practicable for application.
The thermal stability is important for self-luminous SSPCMs that need work a long time yet the outer temperature fluctuates frequently during usage. For practical consideration, the self-luminous SSPCMs should be satisfactorily durable without thermal decomposition or degradation. Thus, the thermal stability was investigated by TGA method that is the commonly adopted method to evaluate thermal stability.
Incorporation of LAL particles into the self-luminous SSPCMs can endow the self-luminous function, absorbing and storing visible light sources in the daylight but slowly releasing blue light in the dark over a long time. Thus, the self-luminous SSPCMs can achieve thermal and light energy storage.
In conclusion, the self-luminous material SSPCMs with high latent heat, suitable phase change temperature, effective storage of thermal energy and light energy, and outstanding stability and reliability, have a new way to expand the additional functions other than TES function in self-luminous emergency signs and wallboard for buildings.