Salt-based PCMs

A comparison between organic and salt-based PCMs is provided in Table 7.3. Today, most popular PCMs used in textile applications are based on paraffins (waxes). Compared to other PCMs, paraffins have high heat-storage capacities. 

One disadvantage of paraffin-based PCMs is their low resistance to ignition, but the addition of fire retardants can overcome this problem Furthermore, paraffins have, in general, a lower density than PCMs produced by TEAP (www.teappcm.com) consequently, paraffins have less thermal capacity per unit volume. Paraffins also have a lower thermal conductivity, both in sohd and hquid phases, than inorganic salt-based PCMs, and this may present problems for designers in the heat-transfer process. 

Given that inorganic filler is a mixture of salts (potassium, magnesium ehlo-rides magnesium sulfates potassium and ammonium nitrates), it was shown (Table 1.2) that exactly nitrogen-containing salts led to a significant increase of the melt flow index in sevilene-based PCMs. 

The dependence of e on position allows to describe both local saturation effects, and, in salt solution, the dependence of e on concentration. In numerical grid methods (there are families of methods, called Finite Elements Methods, FEM, and Finite Differences Methods, FDM - see Tomasi and Persico (1994) for a short explanation of differences) there is nothing but a little increase in complexity in treating eq.(lll) instead of eqs.(109-110). The treatment of the latter model by means of a MPE method is more difficult, and a specialized PCM version (Cossi et al., 1994) is necessary to exploit it with a BEM-derived method (see Juffer et al., 1991, for another proposal based on the BEM technique). 

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