A. Saravanan

Four distinct neural models were used to evaluate the efficiency of a V-trough solar water heater (VTSWH) equipped with square-cut twisted tape (SCTT) and V-cut twisted tape (VCTT) at two different twist ratios, 3 and 5. The objective of this study was the use of ANFIS (Adaptive Neuro-Fuzzy Inference System), G.L.R. (Generalised linear regression), R.T. (Regression tree), and SVM (Support Vector Machine). A total of 162 data sets were acquired for these models through a variety of trials. Outdoor experiments were done using a twist ratio of Y = 3 and Y = 5, using both SCTT and VCTT. The models included eight distinct variables: ambient temperature, water mass flow rate, water intake temperature, water exit temperature, absorber plate temperature, tube temperature, solar intensity, and twist ratio. The dependent variables in this study are the Nusselt number (Nu), friction factor (FF), and efficiency (η). 130 datasets were chosen for training purposes, while 32 were used for testing. Using the ANFIS, G.L.R., R.T., and SVM techniques, the correlation coefficient (R²) values for Nusselt number were 0.9990, 0.9961, 0.9562, and 0.9280 for friction factor 0.9966, 0.9683, 0.9810, and 0.9560, and for efficiency 0.9997, 0.9976, 0.9845, and 0.9614, respectively. Comparing all models shows that ANFIS is the most effective of the four strategies studied. The ANFIS model outperformed the other models regarding Nu, FF, and η, with RMSE values of 0.0805, 0.0.0004, and 0.4534. According to the above data, the VTSWH thermal performance predicted using the ANFIS approach has the highest accuracy.

The need for freshwater grows by the day, yet the amount of freshwater accessible worldwide is insufficient to fulfil it. The distillation of saltwater could be a way to meet the demand for freshwater. The current study investigates the experimental performance enhancement of a tubular solar still (TSS) with various rotating wick materials. A rotating drum consisting of multiple wick materials (black bamboo cotton fabric, jute cloth, terry cotton, and polyester) was placed within the tube to increase the evaporation rate. The basin water depth was set at 2 cm to increase the productivity of distillate water. The black bamboo cotton fabric wick outperformed the jute cloth wick, terry cotton wick, polyester wick, and conventional tubular solar still (CTSS) by 5.7%, 12.44%, 19.94%, and 48%, respectively, while maintaining the wicked drum speed around 1 rpm. Because of its moisture-wicking nature, the efficiency of a TSS with a rotating wick made of black bamboo cotton fabric is 50.65% greater than that of a CTSS. Compared with other wick materials, it had a high absorption and evaporation rate. Furthermore, the performance of TSS was investigated, using a black bamboo cotton fabric wicked drum at 0.3, 0.5, 1, 2, and 3 rpm. The studies indicated that a wicked drum speed of 0.5 rpm improves the productivity of approximately 7.474 kg/m2. Furthermore, the average TSS efficiency was increased by 70.8% compared with the CTSS.

This experimentation deals with the comparative study of a flat plate wick-based solar water distillation system (SWDS) with and without V-trough (VT) solar collector (SC) under the actual environmental conditions of Salem, Tamilnadu, India, as an attempt to enhance the productivity of the solar water distillation system. The influences of wick material, solar intensity, flow rate, and ambient temperature on productivity are also proposed. To ensure accuracy in the experimentation, the overall observation is divided into four spells with four different wick materials. The hourly productivity of the proposed still is compared with the standard theoretical equation, and the deviation between them is well accepted with ±10.14%. The maximum convective and evaporative heat transfer coefficients are observed during spell 3 as 2.488 W/m2K and 25.321 W/m2K, respectively. The prediction of Nusselt number and Sherwood number are also proposed to validate the heat transfer and mass transfer, respectively. Compared to polyester, terry cotton, and jute wick materials, fur fabric wick yielded maximum productivity of 4.40 l/day and 6.29 l/day for SWDS alone and SWDS with VT, respectively. The results revealed that the productivity of the SWDS coupled with V-trough SC is 30.12% greater than SWDS alone.

In this present work, the influence of corrugated booster reflectors (CBR) in a centrally finned twist (CFT) inserted solar thermal collector (SC) on heat transfer and thermal performance characteristics has been approached experimentally. The experimental trials have been made with two different twist ratios (Y = 3 and 6) for typical twist (TT) and CFT under same working conditions. The results were compared with the plain tube SC with CBR plain and also with the plain tube SC with flat booster reflectors (FBR plain). The experimental result of the CBR plain has been verified with the standard equations and found the deviations within ±10.05% for Nusselt number and ±9.42% for friction factor. The CBR has 1.6% higher effective reflection area than the FBR. Hence, the CBR augmented the Nusselt number around 8.25% over the FBR. When compared to the CBR plain, the CFT of minimum twist ratio (Y = 3) offered 10.09% higher thermal efficiency. In addition, empirical correlations have been derived for predicting the Nusselt number and friction factor. The deviations of the predicted value from the experiment value fall within ±10.62% for Nusselt number and ±11.28% for friction factor.