Energy storage systems designers normally use the thermophysical propertiesof phase change materials (PCMs) from the manufactures/suppliers data sheet.Unfortunately, sometimes PCMs systems do not behalf according to supplierdata sheet, especially after cycling use. Designing systems based on these unre-alistic data sheet make the system operates at off design conditions most oftime. The problem is substantially appears in salt hydrates PCMs systems. Inthis short communication, a case study of such discrepancies in air free coolingis addressed. The system design was based on SP24E PCM data sheet, butresults showed that liquids and solidus lines cannot shown on the temperaturetransient history during charging and discharging process, and complete solidi-fication and melting could not be obtained. For further detailed investigations;differential scanning calorimeter (DSC) tests were conducted for SP24E PCMand completely different results than supplier data sheet were obtained DSCtests showed (a) a wide range of temperature variation during melting andsolidifications, (b) phase change starts and ends at lower temperatures com-pared with supplier data sheet, and (c) phase change latent heat is lower thanthe one listed in supplier data sheet. |
