Available online at ScienceDirect. Energy Procedia 90 (2016 )

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1 Available online at ScienceDirect Energy Procedia 90 (2016 ) th International Conference on Advances in Energy Research, ICAER 2015, December 2015, Mumbai, India Performance Assessment of Solar Agricultural Water Pumping System V.S.Korpale a,d.h.kokate a,s.p.deshmukh a* a Department of General Engineering, Institute of Chemical Technology,Matunga Mumbai ,India Abstract The solar photovoltaic based agricultural water pumping system is best suited technology for irrigation of farms. The generation of electrical power from Photovoltaic cell is mainly dependent on solar irradiations at respective times. The study reported in this paper deals with characteristic study of existing water pumping system based on solar photovoltaic power and conventional electrical power. Thin film Cd-Te solar panels were used to power 2HP existing water pump. The performance of solar powered water pump was as equal as pump powered by conventional one. The efficiency of solar based water pump is much higher than conventional power based water pump. The maximum flow rate obtained was 69 LPM against 65 LPM for conventional power method. MPPT was used to track best operating point of solar PV array. The outcomes of reported study are important making socio-economic impact on Indian agricultural sector The The Authors. Published Published by Elsevier by Elsevier Ltd. This Ltd. is an open access article under the CC BY-NC-ND license ( Peer-review under responsibility of the organizing committee of ICAER Peer-review under responsibility of the organizing committee of ICAER 2015 Keywords: Thin Film Cd-Te Solar panels; MPPT, Solar photovoltaic power. 1. Introduction Demand of electricity in India is now becoming scares. According to sectorial demand pattern of electricity, the demand of electricity for Agriculture is 21.5% [1]. The Agriculture sector with demand potential of ¼ of the whole, but demand always not been fulfilled. Agriculture sector in India shows very slow growth rate, sometimes negative also. The farming requires majorly two valuable resources viz., water and electricity. These two are analogous to each other because of similar impact on Agriculture sector. Thus the conservation of these resources would save deterioration Agriculture sector. In recent years the development of renewable energy sources viz., solar PV technology is being popular. Due to High Grade energy output the PV cells are used to run the electrical equipments directly. One of the remarkable applications of solar PV is to provide electricity to Agricultural water pumps. As the integrated model is being very popular in the market, the energy conservation possibilities are now increased to The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license ( Peer-review under responsibility of the organizing committee of ICAER 2015 doi: /j.egypro

2 V.S. Korpale et al. / Energy Procedia 90 ( 2016 ) reduce burden on existing grid. Many research studies were carried out to regularize the performance of water pumps based on solar energy. P. E. Campana et al [2] studied water demand of crops and requirement of solar power. The dynamic modeling and sizing of photovoltaic water pumping system was carried out to assess economic optimization. The sizing of photovoltaic water pumping system is greatly affected by variable demand of water for crops. Also the steady efficiency value of water pumping efficiency is required to find out optimal size of PV array. The availability of ground water is the main factor in assessment of motor-pump set. A.A. Ghoneim et al [3] studied five parameters model and validated within the range of 2.5%. Campana and Zhang [4] worked on economic optimization of photovoltaic water pumping system for irrigation purpose. They stated models separately in discretized system viz., model for voltage characteristics of PV output, inverter-water pumping system model, crop growth model and groundwater supply model. Modeling study helped to reduce size of PV module from 1.44 m 2 to.96 m 2. Deveci and Onkul et al [5] worked on development of low cost solar powered Drip irrigation model. They concluded that increase in temperature of solar PV panel doesn t affect overall system efficiency. But due to increase in available solar radiations the divergence in MPPT (maximum power point tracking) would be observed. This divergence can be avoided through MPPT controllers. Also direct coupled PV based water pumping shows increment in flow rate from 8.00 am to am. Direct coupled photovoltaic systems could give maximum flow rate at higher intensities. R.Lopez-Luque [6] developed similar type of PV water pumping model to design standalone system for olive orchads. Tomas Correa and Rocha Silva [7] worked on efficiency optimization of standalone photovoltaic water pumping system. They focused on MPPT and MLPT (Minimum loss point tracking) methods on improvement of system efficiency. An implementation of MLPT in addition to MPPT would increase pump output in nearly constant solar radiation environment. All the mentioned studies focus on performance of integrated PV water pump system with their economic analysis. Here a technology gap can be analyzed regarding water pump. Farmers already use water pumps for irrigating their farms. Hence they cannot afford specially designed solar water pumps. Hence there is a scope to study a performance of existing water pump based on solar PV power. The research work presented in this paper deals with performance comparison of existing 3-Phase submersible pump powered by conventional and solar photovoltaic array. Nomenclature D Diffused Solar Intensity (W/m 2 ) G Global Solar Intensity (W/m 2 ) h Required pumping height (m) I sys, I System Current based in solar PV, Current based on conventional power (A) P a Active power supplied to motor-pump set (W) P ap Reactive power supplied to motor-pump set (W) PF Power factor Q Discharge of water (m 3 /s) T Time (min) V sys, V System Voltage based in solar PV, voltage based on conventional power (V) n Efficiency of water pumping (%) ρ Density of water (kg/m 3 ) 1.1. Methodology Solar energy is clean and cheap source of energy. Proper utilization of solar energy for different industrial and household requirements are now need of time. The technique of solar based water pumping is essential technology to conserve valuable resources i.e. water and energy. The one of the important application of this technology is to irrigate farm crops. Existing solar water pump technologies available in the market comprises both DC and AC pumps. Major hindrance in commercialization of any solar technology is the cost per watt of installed system. Higher income farmers can afford new integrated system i.e. solar PV panel with DC motor pump set. Low and

3 520 V.S. Korpale et al. / Energy Procedia 90 ( 2016 ) middle income level farmers cannot afford high cost of integrated system. So they rely on conventional power source from MSETCL or other private electricity supplier companies. Ultimately the model of integrated solar water pumping technique and related policies become useless to recover defined revenue. Here an attempt has been made to absorb existing AC water pumps of farmers. The experimentation work was carried out on bore well submersible pump at Institute of Chemical Technology. 2. Equipments and Methods: The performance of PV based water pump depends upon solar intensity of respective date and time. Several photovoltaic system combinations are prescribed in the literature are stated below. [8] Grid connected PV array system Standalone PV array with DC line output Standalone system with AC line output The experimental setup comprises a thin film PV array with standalone AC line with existing 3-phase induction motor. A DC/DC frequency tuner and DC/AC inverter collectively called controller of 465 DC volt capacities is connected in the system. A thin film PV module of Cadmium Telluride Cd-Te comprising installed capacity 2.7 KW are used to generate DC power from solar radiations. Panel arrangement is 9 connected in series. Two rows of 9 panels each are connected in parallel. The maximum power point tracking method was used to track best operating point of solar PV panel. A resistance box comprising different resistance values is used for MPPT experiment. Solar PV array 9X2 + - RY B DC/AC controller Existing pumpmotor system Fig. 1. Schematic of experimental solar PV based water pump setup AC output from controller is connected to 3-phase submersible motor-pump set. Solar radiation pyranometer is used to measure solar global and diffused radiations. An Energy auditor meter SPVR 96U (MECO) is used to record power consumption, system voltage-current and power factor at an instant of motor pump system operation. A change over switch is used between controller output to motor-pump set to ensure both conventional or solar power based operation as per requirement. The discharge and pressure at the pump outlet are measured using Rotameter and pressure gauge mounted at outlet. The auto focusing systems are somewhat costly and are unaffordable for medium level income farmers also. As the basis of proposed research work is to minimize cost of water pumping and simultaneously conserve energy, so the PV panels are tilted at a fixed angle.

4 V.S. Korpale et al. / Energy Procedia 90 ( 2016 ) MPPT procedure: Connect the resistance box, solar panel and ammeter in series. Connect voltmeter across the two terminals of resistance box. At zero current value voltage is called Open circuit voltage. Make any number of equal steps of resistance from zero to high value. Add appropriate high resistance in a circuit. Measure the current and voltage. Reduce the resistance by 1 step and again measure current and voltage. Repeat the procedure for each step and record the variation of current against voltage. 3. Equations The water pumping efficiency is calculated based on following equation. Water pumping efficiency in %, ρ. Q. g. h*100 n = Pa (1) 4. Illustrations 4.1. Variation of solar intensity: Mumbai is located on N; E on longitude and latitude with annual global solar radiation exposure is MJ/m2 and diffused solar radiation exposure 8.52 MJ/m2. A variation in global and diffused solar radiations on a typical day has been presented in Fig. 2. Fig. 2. Solar Intensity variation over the daytime The global intensity at 10:00 is increasing slightly upto 12:30. The maximum solar intensity recorded was 843 W/m 2. At noon sometimes due to cloudy environment intensity falls down. At the same time diffused intensity increases due to cloudiness. It merely affects the performance of load connected in the circuit i.e. motor-pump. At the intensity falls down upto 600 W/m2. Based on recorded intensity the electrical characteristics of motor pump are presented in Fig. 5.

5 522 V.S. Korpale et al. / Energy Procedia 90 ( 2016 ) Maximum power point tracking: Maximum power point tracking method is used to calculate best operating point of solar photovoltaic system. A single panel in the array of 150W and 50.5 V DC capacity was used to find out best operating point. The best operating voltage and current range obtained was V DC and respectively Electrical Characteristics: Fig. 3. Maximum power point tracking of 150W thin film solar panel Fig. 4 shows variation of current and voltage with fluctuation solar intensity on respective time of day. The maximum DC voltage and current obtained from solar PV array was 376 V and 2.5 A respectively at the 12:15 day time. Fig. 4. Variation of system AC Current and AC voltage based on PV power input The maximum AC system voltage obtained was 308 VAC with 4.38 A current. The average AC voltage and current recorded as VAC and 2.33 respectively. The AC voltage shows almost flat linear trend with little fluctuations. The system current curve is fluctuating in nature but exhibiting nearly linear nature.

6 V.S. Korpale et al. / Energy Procedia 90 ( 2016 ) Fig. 5. Variation of system AC Current and AC voltage based on conventional power input Similar electrical characteristics were studied based on conventional power presented in Fig. 5. The study was carried out for 40 min. The AC voltage is showing more fluctuations compared to AC current. The average system AC voltage was 392 and current was 5.5 A. A concluding remark has been made as the motor exhibits same electrical characteristics with only 7% loss of AC voltage of solar PV as compared to conventional electricity Performance of Pump The typical active AC power input given to motor pump set has been presented in Fig. 6. The average active power over the time of day was 276 W with power factor The maximum power factor obtained was with maximum AC power of 339W. (A) (B) Fig. 6. (A) Performance of motor pump with PV energy input (B) Performance of motor pump with conventional energy input

7 524 V.S. Korpale et al. / Energy Procedia 90 ( 2016 ) Fig. 7. Performance of submersible pump based on solar PV power input In Fig. 7 the discharge shows linear relationship with solar intensity. The maximum discharge obtained was 1.15X10-3 (69 LPM) with maximum solar intensity. The maximum discharge obtained with conventional electricity was 65 LPM. Here a conclusion can be made as the discharge obtained due to PV input is little more than conventional. The possible reason is that PV arrays are at MPPT point. The average efficiency of solar based water pumping obtained was 39 % as compared to 10% efficiency of conventionally powered motor pump set. 5. Conclusion In the present study a comparison of solar based water pump and conventionally powered water pump was reported. Based on system response to different power sources some of the important conclusions can be drawn as follows: An existing submersible pump can be absorbed in the system with good process adaptation. Due to solar PV based output the efficiency of solar pump was increased to 39%. Motor characteristics are almost equal for PV power source and conventional power source. MPPT controllers are necessary to obtain best efficiency points of solar PV array. References [1] CIRSIL, Customized Research Bulletin. CRISIL, (2014)1-28. [2] Pietro Elia Campana, Hailong Li, Jinyue Yan. J. Applied Energy (2013), p. 11. [3] A.A.Ghoneim, Energy Conversion and Management 47 (2006), pp [4] P.E.Campana, H.Li,J.Zhang,R.Zhang, J.Liu,J.Yan., Energy Conversion and Management 95(2015), pp [5].Onur Deveci, Mert Onkol, Hakki Ozgur Unver, Zafer Ozturk. Elsevier Ltd. (2015), pp [6] R.Lopez-Luque, J.reca,J.Martinez., J Applied Energy 149 (2015), pp [7] Tomas Perpetuo Correa, Seleme,Issac Seleme Jr,Selenio Rocha Silva., J. Renewable Energy41(2012), pp [8]Bureau of Indian Standards, IS14153 (1994), pp. 1-8.