Polyethylene glycol-based phase change materials with high photothermal conversion efficiency and shape stability in an aqueous environment for solar water heater

2021 ◽  
pp. 106778
Author(s):  
Huizhi Yang ◽  
Yufeng Bai ◽  
Chunhua Ge ◽  
Lili He ◽  
Weiyue Liang ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Phase Change ◽  
Conversion Efficiency ◽  
Phase Change Materials ◽  
Aqueous Environment ◽  
Solar Water Heater ◽  
Water Heater ◽  
Shape Stability ◽  
Photothermal Conversion ◽  
Solar Water

Preparation and Evaluation of PCMs by Macro Encapsulation for Solar Energy Storage

2021 ◽  
Vol 14 ◽  
Author(s):  
Sunita Routray ◽  
Vishal Agarwal ◽  
Ranjita Swain ◽  
Rudra Narayan Mohapatro
Keyword(s):  
Phase Change ◽  
Large Scale ◽  
Phase Change Materials ◽  
Low Cost ◽  
Storage System ◽  
Solar Water Heater ◽  
Water Heater ◽  
Latent Heat Storage ◽  
Solar Water ◽  
Thermal Fluids

Abstract: Phase Change Materials (PCMs) are used in a latent heat storage system for storing thermal energy. The thermal conductivity of PCMs is enhanced by macro encapsulation for large-scale use. This technique not only provides a self-supporting structure of PCM, also separates the PCM from thermal fluids and enhances the heat transfer rate. The current work involves the study of encapsulation of low-cost inorganic PCMs, such as Sodium nitrate (NaNO3), in a temperature range of 300 – 500˚C. Silicate coating is also applied to PCM capsules. A Solar water heater is then designed using the macro encapsulated PCM. The water heater consists of copper cylindrical pipes, filled with the phase change material. The efficiency of the solar water heater is found to be 22.5%.

Evacuated Tube Solar Collectors Integrated With Phase Change Materials and Silicone Oil

2017 ◽  
Author(s):  
Alexios Papadimitratos ◽  
Sarvenaz Sobhansarbandi ◽  
Vladimir Pozdin ◽  
Anvar Zakhidov ◽  
Fatemeh Hassanipour
Keyword(s):  
Phase Change ◽  
Solar Collector ◽  
Phase Change Materials ◽  
Silicone Oil ◽  
Solar Water Heater ◽  
Water Heater ◽  
Solar Water ◽  
Water Heaters ◽  
Evacuated Tubes ◽  
Solar Water Heaters

This paper presents a novel method of integrating Phase Change Materials (PCMs) and Silicone oil within the Evacuated solar Tube Collectors (ETCs) for application in Solar Water Heaters (SWHs). In this method, heat pipe is immersed inside the phase change material, where heat is effectively accumulated and stored for an extended period of time due to thermal insulation of evacuated tubes. The proposed solar collector utilizes two distinct phase change materials (dual-PCM), namely Tritriacontane paraffin and Erythritol, with melting temperature 72°C and 118°C respectively. The integration of Silicone oil for uniform melting of the PCMs, utilizes the convective heat transfer inside the evacuated tubes, as this liquid polymerized material is well known for its temperature-stability and an excellent heat transfer medium. The operation of solar water heater with the proposed solar collector is investigated during both normal and stagnation (on-demand) operation. The feasibility of this technology is tested via small scale and large scale commercial solar water heaters. Beyond the improved functionality for solar water heater systems, the results from this study show show efficiency improvement of 26% for the normal operation and 66% for the stagnation mode compared with standard solar water heaters that lack phase change materials and silicone oil. The benefit of this method includes improved functionality by delayed release of heat, thus providing hot water during the hours of high demand or when solar intensity is insufficient such in a cloudy day and during night time.

ANALISA PENGARUH PENAMBAHAN THERMAL ENERGY STORAGE PADA PEMANAS AIR TENAGA SURYA TIPE PLAT DATAR

POROS ◽  
2017 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Maharuli Maharuli ◽  
I Made Kartika ◽  
Harto Tanujaya
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Heating Process ◽  
Solar Water Heater ◽  
Solar Thermal Energy ◽  
Water Heater ◽  
Solar Water

Abstract: Solar energy, the renewable energy is only available at certain hour. So it is essential to develop efficient, economical solar thermal energy storage. Thermal energy storage (TES) systems provide several alternatives for efficient energy use and conservation. Phase change materials (PCMs) for TES are materials supplying thermal regulation at particular phase change temperatures by absorbing and emitting the heat of the medium. TES in general and PCMs in particular, absorb energy during the heating process as phase change takes place and release energy to the environment in the phase change range during a reverse cooling process. PCMs possesses the ability of latent thermal energy change their state with a certain temperature. Paraffin is the PCM used in this research. Paraffin is being added to a solar water heater to store thermal energy at daylight and supply the stored energy to the heat pipe when the sundown. From this research, it is found that the solar water heater with paraffin need longer heating time than the conventional solar water heater but it could provide steadier heating performance and warm water even when the sun was down. 

scholarly journals Cellulose Nanofibers/Melanin Hybrid Aerogel Supported Phase Change Materials with Improved Photothermal Conversion Efficiency and Superior Energy Storage Density

2021 ◽  
Author(s):  
Jiulong Chen ◽  
Yiyang Zhang ◽  
Fugeng Wu ◽  
Bin Guan ◽  
Xiaosheng Du ◽  
...  
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Conversion Efficiency ◽  
Phase Change Materials ◽  
Cellulose Nanofibers ◽  
Structure Stability ◽  
Energy Storage Density ◽  
Shape Stability ◽  
Storage Density ◽  
Photothermal Conversion

Abstract Organic phase change materials (PCMs) have been widely applied in thermal energy storage fields due to their good structural stability, high energy storage density, adjustable phase change temperature and non-toxic. However, the poor solar-thermal conversion performance and structure stability restrict the large-scale application of organic PCMs. Herein,novel PCM composites (CMPCMs) with good structure stability, improved photothermal conversion efficiency, and superior energy storage density were successfully synthesized by impregnating poly (ethylene glycol) (PEG) into cellulose nanofibers/melanin hybrid aerogel. The three-dimensional (3D) aerogel framework had good shape stability and strong encapsulation ability, which inhibited the leakage of PEG and enhanced the shape stability of the synthesized PCM. The differential scanning calorimetry (DSC) results showed that CMPCMs exhibited relatively high melting enthalpies ranging from 168.3 to 175.9 J/g, and the introduction of melanin almost unchanged the energy storage density of the synthesized PCM composites. Simulated sunlight test revealed that the introduction of melanin significantly improved the photothermal conversion efficiency of CMPCMs (from 47.2 to 85.9%). The thermal cycling test and thermogravimetric analysis showed that CMPCMs possessed excellent thermal stability and good encapsulation ability. In conclusion, the synthesized CMPCMs showed great potential in the practical utilization and storage of solar energy.

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