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ThesisItem Open Access Developing and testing of a collector-cum-storage types solar water heater for domestic use(Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2000) Bijukumar, K; KAU; Mohammad, C PThe present study was undertaken to desi~n and develop a collector-cum-storage type solar water heater of 30 litre capacity to supply hot water for domestic use. Five solar water heaters with different absorber plate positions were constructed. The storage tanks with dimensions of 67 xIl7 x 10 cm were made by using fibre glass, and the top of these storage tanks were covered using single plain glass plates of 71 x 51 x 0.4 cm size. The position of the absorber plate was varied by changing the width of the spacers (4 nos. at an angle of 400 with the side aluminium sheet), which connects bottom aluminium plate and top absorber plate. The absorber plate was of 65 x 45 cm size. The top face of the absorber plate was painted black to absorb maximum solar. radiation. The absorber plate positions were lcm, 3cm, 5cm, 7cm and 9cm from the top glass cover plate and were designated as SWHl 0, SWH30, SWH5.0, SWH7.0 and SWH9.0 respectively. The absorber plate position was optimized by testing the solar water heaters under two different test conditions. Solar water heater II (SWH3.0) outperforms other solar water heaters under the two test conditions. Maximum outlet temperature of 64°C af 3pm and maximum efficiency of 55.72% also at 3pm were observed in solar water heater 11. So it is optimized that the position of the absorber plate should be at 3cm from . the top glass plate. The solar warer heater can easily be handled by a single person since the weight is only 9.5kg. The operating cost per unit of thermal energy obtained withthe solar water heater was found to be 25 paise per kWh.ThesisItem Open Access Development of a cono-puddler attachment for a 5HP tiller(Department of Farm Power Machinery and Energy, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 2000) Tejendra Sharma; KAU; Ramachandran, V RA 5hp power tiller operated cono – puddler was fabricated based on the IRRI design and tested. Based on the test result, four more models of cono – puddlers were fabricated and tested. Out of the five models, four were walking behind type implemented and were tested at travel speed of around 0.786 m/sec whereas one was of riding type (model – 5) and was operated at travel speed of around 0.964 m/sec. All the models were tested for three and four times operations. The depth of puddling of the model – 1 was 10 – 11 cm. Another set of conical rotors was fabricated by increasing the blade height to 90 mm from 70 mm (model – 2). The depth of puddling obtained was 12.2 to 13.8 cm. Because of the problem of clogging of soil in between the blades and due to a wide gap in between the rotors which leaves the soil uncut, another set of rotors was fabricated by increasing and modifying the shape of the blades to helical and tested (model – 3). The above three models consisted of six conical rotors clamped individually on a toolbar assembly. Another model, (model – 4) was tested by increasing the number of rotors of model – 3 to eight numbers. The maneuverability of this model was not good as it was difficult at the time of headland turning. The average percolation loss of water for the five models measured for 20 days after puddling varied from 3.692 to 3.979 mm/day for three time operations and 2.650 to 2.983 mm/day for four times operations. The least percolation loss of water was observed in case of model – 5 and highest in case of model – 1 in both numbers of operations. The puddling indices for the five models varied from 56.31 to 59.34 per cent for three times operations and 63.46 to 68.89 per cent for times operations. The highest puddling index was observed in case of model – 5 in both numbers of operations. The average percentage burial of weeds from different test plots varied from 98. 38 to 98.79 per cent in terms of number of weeds and 99.09 to 99.34 per cent in terms of dry weight basis for three times operations. The variation was from 98.94 to 99.69 per cent in terms of number of weeds and 99.40 to 99.83 per cent in terms of dry weight basis for four times operations. The effective field capacities for model – 1, model – 2, model – 3, model – 4 and model – 5 were 0.826, 0.790, 0.843, 0. 826 and 1.053 ha/day respectively for three times operations and 0.618, 0.598, 0.613, 0.643 and 0.799 ha/day respectively for four times operations. The field efficiencies of the five models for different number of operations varied from 52.58 to 72.20 per cent where field efficiency of model – 4 was observed least in both number of operations. In both cases, field capacity and field efficiency of the model – 5 was highest. The draft of model – 1, model – 2, model – 3 model – 4 and model – 5 were 40.68, 45.03, 46.81, 48.19 and 58.06 kg and draw bar horse power requirement were 0.426, 0.472, 0.491, 0.505 and 0.746 hp respectively. The power required for the model – 5 was higher than the other models. The fuel consumption rate for the five models operated at different number of operations varied from 0.495 It/h in case of model – 1 operated three times to 0.666 It/h in case of model – 5 operated for four times. The slippage of the ground wheel for the five models varied from 0.811 per cent to 3.588 per cent. Lowest ground wheel slippage of 0.881 per cent was observed in model – 1 operated three times and highest of 3.588 per cent in model – 5 operated 4 times. The cost of puddling one hectare of land using model – 3 and model – 5 are Rs. 534.39 and Rs. 432.83 when operated for four times and break even point is 1.2 ha compared to animal drawn country plough.
