Evaluation of paraffin/water emulsion as a phase change slurry for cooling applications

A Phase Change Slurry (PCS) is a latent heat storage and transfer medium consisting of a Phase Change Material (PCM) as a dispersed phase and a carrier fluid as a continuous phase. PCSs have a high energy density because they use not only the sensible heat capacity of the carrier fluid, but also the latent heat capacity of the PCM during the phase transition. In this paper, a paraffin/water emulsion has been studied as a PCS for comfort cooling applications in a temperature range of 0–20°C. A paraffin blend having a melting temperature range of 2–12°C was used for preparing the emulsion. The properties of the emulsion were studied in view of the application requirements on PCSs. The dependence between the paraffin fraction and emulsion properties was investigated. The stability of the emulsion was examined both during the storage period and under mechanical–thermal loads in a test rig by determining the change in the properties. The results indicate that the paraffin/water emulsion containing a paraffin weight fraction of 30–50 wt.% is an attractive candidate for cold storage and distribution applications.