scholarly journals The Equation for Rise in Superheat by Adding Electrolyte

Author(s):  
John H. Jennings

For many liquids, the limit of superheat is 0.89 Tc, where Tc = temperature Kelvin at critical point.  The rise in the limit of superheat by addition of polymer has a formula, B’, derived by Jennings, and this paper makes use of a pattern to predict the formula for rise in superheat by adding electrolyte, B. The equations for boiling point elevation by addition of electrolyte, A, and polymer, A’, are known, so we make use of a proportion and solve for the unknown, B, thus: B= (A/A’) x B’ to get the equation. A, A’ and B’ all have the phase change temperature squared at 1 atmosphere pressure in the numerator times the ratio of the molecular weight solvent divided by the product of the density of solvent times molecular weight solute in the expression that equals lim c--->0 (dT/dc) giving the limiting slope of rise in temperature versus concentration solute.  The van’t Hoff factor is included.  The proposed formula B for RISE IN SUPERHEAT BY ADDITION OF ELECTROLYTE is:   lim c--->0 (dT/dc)s, electrolyte = (3 k MW1 Ts 2 i) / (ρ1  σ1 a MW2(e)).             

2006 ◽  
Vol 326-328 ◽  
pp. 1275-1278 ◽  
Author(s):  
Chang Oh Kim ◽  
Jin Heung Kim ◽  
Nak Kyu Chung

This study aims to find out cooling characteristics of TMA 25wt%-water clathrate compound with ethanol such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at -6, -7 and -8, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as 5.1 and 5.0, 3.8 according to cooling source temperature in case that 0.5wt% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is 0.9 and minimum supercooling is 0.8, 0.7 according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is 3.013~3.048 kJ/kgK according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol.


2017 ◽  
Vol 21 (5) ◽  
pp. 15-23
Author(s):  
Muhammad Irsyad ◽  
Yuli S. Indartono ◽  
Ari D. Pasek ◽  
Willy Adriansyah

2020 ◽  
pp. 2000429
Author(s):  
Al-Amin Ahmed Simon ◽  
Lyle Jones ◽  
Yoshifumi Sakaguchi ◽  
Henri Kunold ◽  
Isabella van Rooyen ◽  
...  

2013 ◽  
Vol 773 ◽  
pp. 534-537 ◽  
Author(s):  
Li Li Feng ◽  
Jing Jing Tong ◽  
Chong Yun Wang

Shape-stabilized phase change material (PCM) composed of polyethylene glycol and silica hollow nanospheres was prepared by a vacuum impregnating method. Thermal properties of the composite PCM were investigated by various techniques. Lower phase change temperature and enthalpy of the composite PCM were observed. It is concluded that the phase change properties of the composite PCM are influenced by the adsorption confinement of the PEG segments from the porous structure of the silica hollow nanospheres.


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