Cellulose nanocrystals supported— PolyHIPE foams for low‐temperature latent heat storage applications

2021 ◽  
pp. 51785
Author(s):  
Zehra Türkoğlu ◽  
Hatice Hande Mert ◽  
Emine Hilal Mert ◽  
Hale Ocak ◽  
Mehmet Selçuk Mert
2021 ◽  
Vol 11 (21) ◽  
pp. 10350
Author(s):  
Didier Haillot ◽  
Yasmine Lalau ◽  
Erwin Franquet ◽  
Sacha Rigal ◽  
Frederic Jay ◽  
...  

The industrial sector is increasingly obliged to reduce its energy consumption and greenhouse gases emissions to contribute to the world organizations’ targets in energy transition. An energy efficiency solution lies in the development of thermal energy storage systems, which are notably lacking in the low-temperature range (50–85 °C), for applications such as district heating or low-temperature waste heat recovery. This work aims to bring a latent heat storage solution from material selection to prototype evaluation. The first part of this paper is dedicated to the characterization and aging of a phase change material selected from a screening of the literature (fatty acid mixture mainly composed by stearic and palmitic acid). Then, this material is encapsulated and tested in a prototype whose performances are evaluated under various operating conditions. Finally, a numerical model validated by the experimental results is used to explore the influence of a wider range of operating conditions, dimensioning choices, and material conductivity improvements.


2007 ◽  
Vol 544-545 ◽  
pp. 645-648
Author(s):  
Chang Oh Kim ◽  
Jin Heung Kim ◽  
Nak Kyu Chung

Ice storage system that water is used as low temperature latent heat storage material, refrigerator capacity is increased and COP is decreased because refrigerator is operated at low temperature due to supercooling of water in the course of phase change from solid to liquid. This study is investigated the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, (CH3)3N) of 20~25 wt% as a low temperature latent heat storage material at -5°C, cooling source temperature. The results showed that the phase change temperature, the specific heat is increased and the supercooling degree is decreased as the weight concentration of TMA became higher. Especially, low temperature latent heat storage material containing TMA 25 wt% has the average of phase change temperature of 5.8°C, supercooling degree of 8.0°C and specific heat of 4.099kJ/kgK in the cooling process. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA-water clathrate compound.


Author(s):  
Wolf-Dieter Steinmann

The availability of cost effective storage capacity is considered essential for increasing the share of renewables in electricity generation. With the development of solar thermal power plants large thermal storage systems have become commercial in recent years. Various storage concepts are applied, systems using solid storage media are operated at a maximum temperature of 680 °C, other systems using molten salt as storage medium show thermal capacities in the GWh range. Heating these storage systems directly by surplus electricity and using the heat later during the discharge process to operate turbines is not very attractive, since the process is limited by the Carnot efficiency. Alternatively, surplus electricity can be used to transform low temperature heat into high temperature heat which is stored in a thermal storage system during the charging process. During discharge, this heat is used to drive a turbine generating electric energy. Theoretically, this concept allows a roundtrip efficiency of 100%. Various options for the implementation of this storage concept have been suggested, using air or CO2 as working fluids. Recently, DLR has demonstrated the operability of a latent heat storage system connected to a steam circuit at 100 bar. The availability of this latent heat storage technology allows new implementations of the storage concept based on heat transformation. Using a left-running Rankine cycle during the charging process, heat from the environment is used to evaporate steam, which is compressed using the surplus electricity. Superheated steam exiting the compressor flows through the thermal storage system composed of latent heat storage sections and sensible heat storage sections. After throttling, the water enters the evaporator again. During discharging, heat from the storage system is used to evaporate and superheat steam, which drives the turbine. A cascaded implementation of this concept, using ammonia for the low temperature part of the process, while water is used for the high temperature part, reaches a storage efficiency of 70%. The integration of low temperature waste heat sources allows the compensation of losses.


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