No abstract

The provisions and applications of renewable energy have great supply-demand gap problem, and thermal energy storage (TES) is a very promising solution to fully utilise the renewable energy and covers off-peak periods. The application of solid-liquid phase change material (PCM) is an effective way of TES based on the techniques of encapsulation and emulsion, but the capsules are easily broken and the emulsions are easily phase separated as they were phase changed for many times, so some other techniques should be developed. The microemulsion PCM slurry was prepared by the combination uses of emulsifiers (i.e. sorbitan monooleate 80 and polyoxyethylene sorbitan monooleate 80), coemulsifier (i.e. butanol), distilled water, purified paraffin and inorganic salts (i.e. potassium chloride). The average particle size in the slurry was about 50 nm, and the slurry was homogeneous after centrifugal acceleration of 1800g (i.e. 'g' is the gravity acceleration) for 5 min and phase change cycles for 1000 times. The latent heat of the slurry was 72.25 J g −1 and the paraffin content in the microemulsion was 43.8 wt %. The slurry can overcome the shortcomings of some other techniques and be expected to be widely applied in the TES.