Effect of the mode and dynamics of thermal processes on DSC-acquired phase-change temperature and latent heat of different kinds of PCM

Abstract

Thermal-energy-storage systems utilizing phase-change materials (PCMs) can find use in many fields, such as solar-energy storage, waste-heat recovery or smart air conditioning in buildings. However, their incorporation into certain building elements and possible utilization of thermal energy are related to the proper understanding of phase-change processes. In this paper, thermophysical properties of five different PCMs were characterised in order to find suitable materials for incorporation into lightweight plasters capable of moderating the interior microclimate of buildings. A DSC analysis as the main investigation method was applied in the range of -10°C to 55°C, with the heating/cooling rates of (1, 5, 10 and 20)°C /min. Based on the DSC data, the temperatures and enthalpies of the phase change were determined as functions of both the modes and dynamics of the simulated thermal process. The obtained results were discussed and proper PCM candidates for an application in lightweight interior plasters were identified. Keywords: phase-change materials, differential scanning calorimetry, phase-change temperature Sistemi za skladi{~enje toplotne energije, ki izkori{~ajo fazne spremembe v materialih (angl. PCMs; Phase Change Materials), se uporabljajo na mnogih podro~jih, kot na primer pri pridobivanju in skladi{~enju son~ne energije, izkori{~anju odpadne toplote, ali v inteligentnih prezra~evalnih sistemih stavb. Kakorkoli, njihova vgradnja v dolo~ene gradbene elemente in mo`no izkori{~anje odpadne toplote, je povezana z ustreznim razumevanjem faznih sprememb. V tem prispevku so bile dolo~ene termo-fizikalne lastnosti petih razli~nih PC materialov, da bi na{li ustrezne materiale za vklju~itev v lahke omete, ki bi bili sposobni uravnavati notranjo mikroklimo stavb. Kot glavna preiskovalna metoda je bila uporabljena DSC (diferencialna vrsti~na kalorimetrija) analiza v temperaturnem obmo~ju med -10°C in 55°C, s hitrostjo ogrevanja/hlajenja (1, 5, 10 in 20)°C/min. Glede na podatke DSC-analize, so bile dolo~ene temperature in entalpije faznih sprememb v odvisnosti od obeh na~inov in dinamike simuliranega termi~nega procesa. Dobljeni rezultati so bili pre{tudirani in najdeni so bili ustrezni PCM-materiali za uporabo v lahkih notranjih ometih. Klju~ne besede: materiali s faznimi spremembami, diferen~na dinami~na kalorimetrija, temperatura fazne spremembe

Can movable PCM-filled TES units be used to improve the performance of PV panels? Overview and experimental case-study

“…These values are much lower than those expected from the product datasheet. The same problem was remarked by Fořt et al [60]. Regarding the specific heat, only a single value of 2000 J kg -1 K -1 is provided by the manufacturer.…”