Study of Magnesium Nitrate Hexahydrate and Magnesium Chloride Hexahydrate Mixture as Phase Change Material

Author(s):  
Qing Ding ◽  
XueGang Luo ◽  
XiaoYan Lin ◽  
HongPing Zhang
Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7108
Author(s):  
Yang Li ◽  
Caixia Wang ◽  
Jun Zong ◽  
Jien Ma ◽  
Youtong Fang

Phase change heat storage material is a preferred material in solar building heating or off-peak electric-heat storage heating technology and is the research focus. A compact phase change thermal storage device has been designed and experimentally studied for improving heating system load in this work. A new type, magnesium nitrate hexahydrate-based phase change material has been studied to improve the cooling degree and crystallization difficulty. The focus of this study is on the heat charging and discharging characteristics of this new phase change material. The heat storage device has two groups of coils, the inner side which carries water and the outer side which is the phase change material. A testing system was built up to value the thermal cycling performance of the heat storage device. The measurement data include phase change material temperature field, water inlet and water outlet mean temperature, heat charging and heat discharging depth, and flow rates over the operating period. The results show the phase change material has a quick response with the operating temperature range of 20–99 °C. Its latent heat is 151.3 J/g at 91.8 °C. The heat storage density of this phase change material is about 420 MJ/m3. The thermal performance degradation is about 1.8% after 800 operation cycles. The phase change thermal storage device shows flexibility and a great potential to improve the capacity and economy of heating systems.


2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2803-2812 ◽  
Author(s):  
Ramalingam Senthil ◽  
Marimuthu Cheralathan

In this work, the use of phase change material in the circular tank solar receiver is proposed for a 16 m2 Scheffler parabolic dish solar concentrator to improve the heat transfer in the receiver. Magnesium chloride hexahydrate with melting temperature of 117?C is selected as the phase change material in the annular space of the receiver with rectangular fins inside the phase change material. Experimental work is carried out to analyze heat transfer from the receiver to heat transfer fluid with and without phase change material in the inner periphery. Energy and exergy efficiency are determined from the measurements of solar radiation intensity, receiver temperature, surroundings temperature, heat transfer fluid inlet and outlet temperatures, storage tank temperature, and wind speed. The experiments were conducted in SRM University, Chennai, India (latitude: 13? 5? N, longitude: 80?16? E) in April 2014. Use of phase change material in receiver periphery increased energy efficiency by 5.62%, exergy efficiency by 12.8% and decreased time to reach the boiling point of water by 20% when compared with the receiver without phase change material.


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