This study presents experimental results for the heat transfer coefficient during pool boiling of DI water and Al 2 O 3-water based nanofluid at saturation conditions. Based on these data, an analysis of the heat transfer enhancement due to the nanofluids was performed. The experiments were performed for Al 2 O 3-water based nanofluid with different volume concentrations (0.0007 vol.% and 0.007 vol.%, corresponding to low and high nanofluid concentration, respectively). A copper surface, with different roughness values (R a = 0.05 lm, corresponding to a smooth surface, and R a = 0.23 lm, corresponding to a rough surface), was used as test section. The nanoparticle average size was 10 nm and the applied heat flux ranged from 100 to 800 kW/m 2. For nanofluid pool boiling, it was observed an increase in the heat transfer coefficient up to 75 %, and 15% for the smooth and rough surfaces, respectively, in comparison to that of DI water. According to results, the surface roughness is strongly affected by nanofluid concentration due to the nanoparticle deposition on the heating surface. The results indicate that the use of nanofluids is effective on pool boiling heat transfer, for moderate heat flux and low volumetric concentration.

As is widely known, the issue of freshwater scarcity affects practically all people, and all are looking for innovative and workable ways to attempt to solve this issue. In this work, a novel method of desalination is proposed. The proposed system consists of a solar collector (PTSC), evacuated pipe (EP), condenser (CU), and separation unit (SU). The working principle of the system is heating the feed saline water using the PTSC and EP and controlling the water flow rate to control the output conditions of the EP. The produced vapor is therefore separated from salty water using the SU. In addition, the generated steam is condensed into the CU to produce a freshwater distillate. Consequently, the effect of solar radiation on the affecting temperatures was tested. In addition, the effect of using different water flow rates (6, 7.5, 10, 20, 40, and 60 L/h) inside the EP on the system productivity was investigated. The primary findings of this work may be highlighted in relation to the experiments conducted. At midday, when ultraviolet irradiance reached its highest, the EP’s water flow entrance and outflow had the largest temperature differential. In addition, the lower the water flow rate inside the EP, the higher the water temperature, the higher the evaporation rate of the system, and the greater the freshwater productivity of the system. At 6 L/h, the water’s highest temperature was 92 °C. Moreover, the best performance of the system was obtained at 7.5 L/h, where the freshwater production and average daily effectiveness of the distillate process were 44.7 L/daytime and 59.6%, respectively. As well, the productivity of EP was augmented by around 11.86% when using graphite nanoparticles. Additionally, the distilled freshwater from the system operating at the flow rate of 7.5 L/h costs 0.0085 $/L.

This article present physiochemical characterization of commonly available agricultural waste residues on dry basis for: (Corn cob, Coconut shell, Cashew nut, Palm kernel shell and Cassava stem) with the view to evaluate their respective suitability for biofuel production using thermochemical conversion process. The investigated respective biomass feedstock milled samples was analyzed in the laboratory for fuel physiochemical characterization. The physiochemical characterization carried out on each biomass waste sample are Proximate Analysis, Ultimate Analysis, Elemental composition analysis and determination of their respective Higher heating Value(HHV). The obtained results revealed that of all the biomass samples characterized, the Coconut shell (CNS), Corn cob(CC) and Cassava stem(CS) samples proved to possess the most suitable characteristics for better bio-oil production. Palm kernel shell(PKS), Coconut shell(CNS) and Cashew nut(CN) due to their obtained low ash content, adequate hardness and fairly high fixed carbon content are generally regarded to be a potential source for making quality grade charcoal (bio-char) using Pyrolysis process. Gasification process is found desirable to producing high yield of bio-gas for Corncob(CC) and Cassava stem(CS) biomass samples due to their respectively obtainable high value of moisture content: (13.4%wt and 15.10%wt.) and fixed carbon contents of (67.94%wt and 74.13%wt) in this study. Moreover, among all other biomass sample investigated in this study, Coconut Shell(CNS) in comparison to all other samples characterized attained highest HHV of 31.2 MJ/kg. Negligible amount of Sulphur and Nitrogen which could resulted to lower emission of SO2 and NO2 if use directly for heating purposes aftermath application of any of the thermochemical conversion processes is also observed for the biomass waste samples analyzed independent of their types. These results show that the characterized biomass samples could be a suitable candidate for alternative energy fuels production in terms of quality and environment concern.