الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
The present study have been carried out to develop an electrical “solar” powered mower (12 voltages battery charged from a photovoltaic solar tnalp) by modifying a gasoline-powered brush cutter to be a trail to overcome the shortage and high cost of fossil fuels and its negative effect on the environment by reducing harmful greenhouse gas emissions. The main results obtained from the preliminary and performance test can be summarized under the following:
Morphological properties of tested plants
The plant avearage stalk height was 75; 82 and 32 cm for alfalfa; clover and grass respectively.while the plant stalk diameter was; 4; 3 and 1.9 mm. for the same plants respectively. On the other hand the plant density was ranged between 6000 to mor than 12000 plant/m2 for the three tested plant; and the moisture containts for the plants during the mowing operation was ranged between 79 to 93 %.
The relation between the plant type, stalk diameter with the cutting force; (N).
The highest cutting force recorded with Alfalfa stalk were 130, 112.6 and 80.5 N. when the stalk diameter were 4; 2.9 and 1.9 mm respectively; while the lowest cutting force recorded with grass were 18.6, 17.3 and 14.7 N. when the stalk diameter were 2; 1.25 and 0.5 mm respectively. It means that there was a direct proportion between cutting force and plant diameter. On the other hand the cutting force recorded with clover were 65.8; 63.4 and 21.4N when the stalk diameter were 4.7; 3.35 and 2 mm respectively.
Performance rate.
The highest perfomance rate was ( 0.127 fed/h) recorded with the grass at the lowest plant density 6000 plant/m2 when the disc speed was 9000 r.p.m. while the lowest performance rate was (0.067 fed/h.) recorded with alfalfa at the highest density 12000 plant/m2 when the disc speed was 3600 r.p.m.; it means that the performance rate was directly proportional to the disc speed and reversaly proportional to the plant density with all the three tested plants.
Performance efficiency.
The highest perfomance efficiency was (54%) recorded with the grass at the lowest plant density 6000 plant/m2 when the disc speed was 9000 r.p.m. while the lowest performance efficiency was (18.63%) recorded with alfalfa at the highest density 12000 plant/m2 when the disc speed was 3600 r.p.m.; it means that the performance efficiency was directly proportional to the disc speed and reversaly proportional to the plant density with all the three tested plants.
Cutting efficiency.
The highest cutting efficiency was (85 %) recorded with the grass at the lowest plant density 6000 plant/m2 when the disc speed was 9000 r.p.m. while the lowest cutting efficiency was (60 %) recorded with alfalfa at the lowest density 6000 plant/m2 when the disc speed was 3600 r.p.m.; it means that the cutting efficiency was directly proportional to the disc speed and reversaly proportional to the plant density with all the three tested plants.
State of charge for the selected battery.
To discibe the state of charge; S.O.C; % for the selected battery at DC motor pulled 15 amper, the battery charging level was 100 % “full charging” when the terminal voltage was 14 volt. While it was 20 % “ full discharging” when the voltage was 8 volt. the current flactuated between the maximum limits at the active stroke and gradiually decreased to the minmum limit at the drawn down stroke.
Energy consumption.The highest energy consumption was (4.831 kW/fed) recorded with the clover at the highest plant density 12000 plant/m2; while the lowest energy consumption was (3.54 kW/fed) recorded with grass at the lowest plant density 6000 plant/m2.
Cost estimation.
The operating cost when using the solar powerd machine was 15.66 L.E/h. and 233.7 L.E/fed; while it was 24.89 L.E/h and 195.9 L.E/fed. When using the gasoline powered machine.
Using the solar powered maching reduce the total operating cost L.E/h by 37 %. On the other hand using the solar powered machine increased the operating cost L.E/fed by 16 % compared with the gasoline powered machine.
CONCLUSION:
Our findings proved the possibility of converting a gasoline engine disk mower into solar powered disk mower exploiting solar energy as a source of power. Herein, it could be concluded that:
1- The solar powered hand-held disk mower was constructed with good and locally available materials. Its performance was satisfactory. The total production cost is quite affordable, compared with the gasoline powered machine; it was helpful for non-commercial use (home users) in maintaining and trimming the grass in gardens, home, or yards. Specially small home lawn less than 1000m2
2- To ensure acceptable performance from the hand held solar mower; DC motor must install directly with the cutter disk.
3- Harnessing of solar energy was a viable solution to the energy crisis in Egypt.
4- Using DC motor instead of the gasoline engine will reduce the mass of the hand held disk mower from 12.5 kg to 9.6 kg, which means easy maneuverability; more working hours and low level of labor fatigue.
5- Using solar power machine having much more advantages i.e, no fuel cost, no pollution and no fuel residue, less wear and tear because of less number of moving components and this can be operated by using solar energy which is vastly available.
6- The electrical circuit incorporating a charging device provides opportunity for continuous operation up to one hour at full battery charge.
7- The machine eliminated noise which is commonly associated with lawn mowers and brush cutters.
RECOMMENDATIONS:
Further research to improve performance rate by using most suitable DC motor.
Having a facility of charging the batteries while the solar powered machine is in motion. So the same work can be operated in night time also, as there is a facility to charge these batteries in day light.
Fabrication of the solar powered lawn mower.
Further study on how to popularize usage of renewable energy should be done.
Replacing solar power with the other Agriculture application will help to overcome the shortage on fossil fuels and electricity.
Offering governmental support and subsidy for the solar equipment. The industries may encourage for producing these components in mass productions, so the cost of the system may come down. So in future it is expected to run all equipment’s by using solar energy.