BULLOCK CART LOADED SPV WATER PUMPING SYSTEM FOR SMALL FARMERS By Dr. A.G.Mohod and Dr. R.T.Thokal Dr. B.S.Konkan Krishi Vidyapeeth, Dapoli Dist. Ratnagiri-415712 (MS) India A. Introduction Wheat is the most important food grain crop in India, occupying approximately 230 million ha world over. India is the second largest producer of the wheat with 25 million ha area and 70 million tones production. About one tenth of the global production is from India. Wheat is grown during winter in the states of Punjab, Haryana, Uttar Pradesh, Bihar, Rajasthan, Madhya Pradesh and Maharashtra. While in northern states it is grown as irrigated crop, in parts of Madhya Pradesh and Maharashtra it is grown largely under rainfed conditions with little or no irrigation support. Well drained loams and clay loams are ideal for wheat cultivation. However, good crops are raised in sandy loams and black soils also. Soil ph below 6.5 and above 7.8 are not suitable. Being low temperature loving crop, it is grown in winter from end of October to February under rainfed conditions and from middle of November to March/April under irrigated conditions. Total duration of the crop ranges from 110 to 120 days under irrigated conditions and 100-110 days under rainfed conditions. B. Crop Water Requirement in Bihar : Total water requirement of the wheat crop is 450-650 mm, which need to be provided over first 100 days of crop growth uniformly. Flood irrigation with canal or bore well water is a common practice. A minimum of five to six irrigations are necessary for optimum productivity. Under assured irrigated conditions irrigation is to be provided at an interval of about 10-20 days, starting from 21, 42, 60, 75, 90 and 100 days of sowing. Total water requirement of vegetables is 550-700 mm and wheat crop is 450-650 mm. Considering the average water requirement as 600 mm for the vegetables and wheat crop and application efficiency through traditional irrigation system as 65%, the gross water requirement comes to be about 950 mm. The irrigation interval for wheat in Northern India is in the range of 10 to 20 days and for vegetables also, 10-15 days. Thus, considering the irrigation interval as 15 days and net irrigation depth as 90 mm each irrigation, total irrigations and net irrigation requirement for crop period will be 6 irrigations and 540 mm, respectively. The gross irrigation requirement per irrigation considering the application efficiency as 70% will be 130 mm. Assuming irrigation rotation period as 15 days and 8
hours as operational time for lifting water through solar pump, the discharge requirement for irrigating one hectare area with solar pump will be A y q= 27. 78 R T Where, q is rate of discharge of pump, lit/sec; A is area to be irrigated in ha; depth of irrigation, cm; R is rotation period in days and T is duration of pumping, hr/day. The pump of 3.00 lit/sec will be required to irrigate one hectare of vegetables or wheat. Considering the total lift including losses of pump as 7m and pump efficiency as 72%, the power requirement pump will be Discharge( lps) totalhead ( m) Horsepower= 76 pump efficiency Horse power requirement of pump will be about 0.40 HP or 300 Watts. C. Source of Power The crystalline silicon solar cell of capacity about 300 Wp ( 4 nos.of panel @ 75 Watt power) will be required for pump discharge of 3 lit/sec and generating electric power for pump of 0.40 HP. The dimensions of commercially available solar panel are 925mm (L) x 660mm (W) x 35mm (T). By connecting two solar panels lengthwise in series on each side of bullock cart, maximum length will be 2000mm. The requirement of bullock cart with length and width of loading platform will be 2000mm (L) and 700mm (W) and height of side panel of loading platform 700mm. Specification of SPV pump PV array- Solar panel made up of crystalline solar cell having certificate of testing confirming to IEC 61215 edition 2/BIS 14286.( 300 Wp) Motor D.C. Motor Pump Set with Brushes or Brush Less D.C.(B.L.D.C.), 300 Wp Dynamic Head- 7 metres Module mounting structure On traditional bullock cart with tracking facilities Water Output- * 60,000 liters per day from a total D. Bullock cart mounted SPV pump Traditionally farmers in India used bullock carts for various farm activities including transportation. The traditional bullock carts in India has the loading platform having dimension of 2 mtr.( L) x 1 mtr (W). The small farmers have at least the bullock cart, which can be used for mounting the solar PV panels along with pump for water lifting and irrigating the crops. The mounting of SPV pump will add about 50 kg additional load, however the mounting does not affect its capacity. This
mounting will facilitate the portability to pumping unit which will be useful for preventing theft of valuable solar panels and pump. This cart mounted with pumping system has two way axis tracking mechanism by proper placement of cart as well as by using the telescopic pipe attached at the yoke to increase the efficiency of solar pump. The water lifting pump has discharge capacity 3.0 lps with 0.40 HP DC pump. This is sufficient to irrigate crop in one hectare area throughout its growing period. The side panels of cart are rectangular in shape and are made up of iron angle frame. Two (02) solar PV panels of size 925 mm (L) x 660 mm (W) x 35 mm (T) can be mounted on each side panel of cart. The four number of 75 Wp solar panels can be fixed on the both side panels through riveting and cushioning to prevent them from vibration during transport. This mounting of solar panels on the cart with pump will be about Rs. One lack. Features of solar bullock-cart: 1. Renewable energy powered alternative 2. Mounted on bullock cart with compact design of solar panels, thus portability is more and can be easily transported to safe location 3. No special design of bullock cart is required as the solar panels and pump will be mounted on normally available dimension cart 4. No special installation is required on the cart, thus same cart can be used for goods transportation 5. Cheap installation and reliable as well as loaded on the locally available carts, care is taken for robustness 6. The bullock cart installed with foldable solar panels can be tracked in two axis with the help of telescopic rod attached at yoke which increase the efficiency and ultimately reduced the size of PV module. Traditional bullock cart in India
Bullock cart in movement Bullock cart during pumping Bullock cart in morning Bullock cart in after noon