Sustainable Thermal Energy Storage Research Articles

3D Printable, Recyclable and Adjustable Comb/Bottlebrush Phase Change Polysiloxane Networks toward Sustainable Thermal Energy Storage

Polymeric solid-solid phase change materials (SSPCMs) have garnered enduring attention due to the excellent latent heat and no encapsulation. However, the green manufacturing and recycling use of polymeric SSPCMs have long-term constraint on the development toward sustainable thermal energy storage. Moreover, 3D printing can help polymeric SSPCMs overcome shape limitations and optimize architectures, resulting in the customer-designed objects and effective thermal management. Herein, we proposed a novel strategy to facilely prepare the 3D printable, recyclable and adjustable comb/bottlebrush phase-change polysiloxane networks (Si-ODT-x). Wherein, the grafting crystalline alkyl chain content can effectively regulate the latent heat (from 24.9 J/g to 125.3 J/g), phase-change temperature (from 24.9°C to 53.6°C), thermomechanical and viscoelastic properties of networks. Besides, the degradation and recycling mechanisms were clarified. Moreover, Si-ODT-100 was exemplarily manufactured as a prototype with shape memory ability via 3D printing. Furthermore, the wearable, recyclable and multi-responsive phase-change composite was fabricated by Si-ODT-25 and carbon fiber cloth, which is suitable for the temperature management of human body. This study skillfully combines the tailorable phase-change ability of comb/bottlebrush networks, recyclability of polysiloxane as well as effective photo-induced thiol-ene click reaction, which will open up infinite possibilities for the thermal energy storage materials.

Thermodynamic analyses and assessments of various thermal energy storage systems for buildings

In this study, energetic, exergetic, environmental and sustainability analyses and their assessments are carried out for latent, thermochemical and sensible thermal energy storage (TES) systems for phase change material (PCM) supported building applications under varying environment (surrounding) temperatures. The present system consists of a floor heating system, System-I, System-II and System-III. The floor heating system stays at the building floor supported with a floor heating unit and pump. The System-I includes a latent TES system and a fan. The latent TES system is comprised of a PCM supported building envelope, in which from outside to inside; glass, transparent insulation material, PCM, air channel and insulation material are placed, respectively. Furthermore, System-II mainly has a solar-thermochemical TES while there are an aquifer TES and a heat pump in System-III. Among the TESs, the hot and cold wells of the aquifer TES have maximum exergetic efficiency values of 88.782% and 69.607% at 8°C dead state temperature, respectively. According to the energy efficiency aspects of TESs, the discharging processes of the latent TES and the hot well of the aquifer TES possess the minimum and maximum values of 5.782% and 94.118% at 8°C dead state temperature, respectively. Also, the fan used with the latent TES is the most environmentally-benign system component among the devices. Furthermore, the most sustainable TES is found for the aquifer TES while the worst sustainable system is the latent TES.