Phase-Change Materials

Današnja praksa održive gradnje zahtjeva brzo i racionalno građenje energetski učinkovitih građevina. Prilikom građenja teži se dematerijalizaciji građevinskih elemenata, što dovodi do umanjenja toplinske akumulacije građevine i posredno do povećanog utroška energenata za grijanje, hlađenje i klimatizaciju. Toplinski kapacitet građevine, naročito kod laganih konstrukcija s izražajnijim problemom, sve češće rješava se uporabom fazno promjenljivih materijala, takozvanih PCM (Phase Change Materials), koji imaju mogućnost pohrane znatno veće topline od konvencionalnih građevinskih materijala. To im omogućuje svojstvo da prelaze iz jednog u drugo agregatno stanje u temperaturom intervalu od 20 do 30 C, te da pritom pohranjuju ili oslobađaju velike količine latentne topline iskoristive za sobnu regulaciju temperature. Na temperaturama nižim i višim od temperature tališta ponašaju se kao ostali građevinski materijali, ali im je specifični toplinski kapacitet obično znatno veći, te i senzibilnom toplinskom energijom doprinose boljim toplinskim karakteristikama građevine u uporabi.Today\u27s practice of sustainable construction requires quick and rational construction of energy efficient buildings. The tendency during construction is to dematerialise construction elements, which leads to the reduction of heat accumulation of building and indirectly to the increased consumption of energy for heating, cooling and air conditioning. The problem of heat capacity, especially notable in lightweight structures, is increasingly solved using phase-change materials (PCM), which have much greater ability to store heat than conventional building materials. This feature allows them to pass from one to another physical condition in the temperature interval of 20-30°C, and at the same time to store or release large amounts of latent heat usable for room temperature control. At temperatures lower and higher than the temperature of the melting point they behave like other construction materials; however, their specific heat capacity is usually much higher, and with sensible heat, they contribute to better thermal performance of buildings in use