Experimental study on tubular solar still using Graphene Oxide Nano particles in Phase Change Material (NPCM's) for fresh water production

Storing of energy in the form of latent or sensible heat is the best method in improving the performance of any thermal application. Desalination using renewable energy is the best method in getting potable water and due to its lower performance and yield it is not commercially available. The present investigation deals with improving potable water produced using nanomaterial in phase change material from a tubular solar still. Three different solar still namely TSS, TSS with PCM and TSS with NPCM were used in the present study and tested under the climatic conditions of Chennai, India. The thermal conductivity of graphene oxide nanoparticle in PCM acts as the key role in improving the thermal performance as the thermal conductivity of NPCM improved by 52% compared to that of PCM without nanoparticle. There is no significant improvement in the thermal conductivity of nano enhanced PCM with concentration beyond 0.3%. With a significant improvement in the thermal conductivity of NPCM, the water temperature increased by 7 °C and 3 °C as compared to TSS loaded with PCM and TSS without PCM respectively. The maximum enhancement in temperature of NPCM is found as 24% and the temperature is higher during off shine hours compared to that of PCM without nanoparticle. Similarly, with improved water temperature using NPCM as energy material, the evaporation rate from the absorber is improved by 41.3%, whereas, the average EHTC for TSS and TSS loaded with PCM alone is improved by 32.76 and 34.32% respectively. The total cumulative yield produced per m² area from TSS, TSS with PCM, and TSS with NPCM is found to be 2.59, 3.35 and 5.62 kg respectively. Results also revealed that the daily efficiency of TSS with NPCM is improved to about 116.5% and comparatively higher than TSS with PCM and conventional tubular solar still.