Introduction: In a solar-powered drip irrigation system, electricity is generated by solar photovoltaic (PV) panels and used to operate pumps for the abstraction, lifting, and distribution of irrigation water.
The increase in population and its demand for water and energy have caused great stress on the world’s water and energy resources. Consequently, it has become essential to replace the conventional sources of energy with renewable energy and conventional methods of irrigation with high-efficiency irrigation to ensure global energy, food, and environmental security.
A guide to solar drip irrigation system benefits
As new irrigation technology becomes increasingly common, manufacturers will want to stay aware of these trends and upgrade their equipment to keep up with customer demand. Drip irrigation pipe should still be produced efficiently and will need to operate with smart systems.
Increasing the production of several crops while minimizing water use is key to operations that want to be both costs effective and environmentally friendly. Water is a critical resource and its preservation wants irrigation systems to optimize their approach. Smart irrigation system design should take into account not only the plants being treated and the amount of water and fertilizer they need. But also the climate of the area, the current and forecasted weather requirements, groundwater levels, the current growth stage of the plants, and more.
A solar-powered drip irrigation system was designed and developed techno-economically for citrus, olive, and grapes. The results with water-saving and fertilizer reduction of more than 50% and 40%, respectively, as compared to conventional irrigation. Further, the system is found cost-effective over the years and wants minimal operational and maintenance costs.
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Components of the solar-powered drip irrigation system
A solar-powered drip irrigation system can be applied in a wide range of scales, from an individual or community vegetable gardens to large irrigation schemes. The components of the solar-powered drip irrigation system can be given below;
Soil moisture sensors can be used for real-time collection of crop root-soil moisture content. And converting it into a signal in the range of 0 – 1 V; and the signal will be transformed as knowledge of water requirement of the crop. The soil moisture content at the root zone of several crops is collected by using the soil moisture sensor. The threshold limit for the water condition for a particular crop has been feed to the system which in turn controls the operation of the control system. The power required for the operation of the control system has been met with the use of a solar panel and the display will receive the control signal and display the data stored using the sensor from the field.
The essential components of the solar-powered drip irrigation system are;
- A solar generator, i.e. a PV panel or array of panels to generate electricity,
- A mounting arrangement for PV panels, fixed or equipped with a solar tracking system to maximize the solar energy yield,
- A pump controller,
- A surface or submersible water pump (generally integrated into one unit with an
- electric motor), and
- A distribution system and storage tank for irrigation water.
Solar-powered drip irrigation model
Drip is the agriculture solar method of irrigation in which water is applied directly to the root zone of plants using applicators that are orifices, emitters, and perforated pipe, etc operated under low pressure with the applicators being located either on or below the surface of the ground. While agriculture solar drip irrigation can be the most expensive method of irrigation, it is also the most advanced and efficient process concerning effective water use.
This agriculture solar drip method of irrigation system contains perforated pipes that are located by rows of crops or buried along their root lines and emits water directly onto the crops that need it. As a result, evaporation is drastically reduced and 25% of irrigation water is conserved in comparison to flood irrigation systems. Agriculture Solar drip irrigation allows the grower to customize an irrigation program most beneficial to each crop. With the given power crisis energy in India with 4 to 6 hours of power is obtainable for agriculture. Solar is free energy with some initial investment. Solar energy will be one of the easiest methods for farmers to produce energy. This model represents how irrigation operates using solar energy. This uses photovoltaic power than the regular power from the grid.
Advantages of using solar-powered drip irrigation
- The solar drip irrigation system is completely automatic and it is a smart irrigation controller the irrigation is controlled by the prevailing weather conditions rather than a program.
- You can also adjust the water usage by adjusting the control dripper.
- The irrigation starts at sunset when there are less evaporative losses and it can be used for both gravity feed and pressurized irrigation.
- The water usage is directly proportional to the net evaporation rate.
- If there is an unexpected heatwave, then the irrigation will respond appropriately.
- When it rains, water enters the evaporator and delays the start of the next irrigation system.
- Uses much less water without affecting the crop yield.
- This system is simple and low tech and so there are fewer things to go wrong.
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Principles of solar-powered drip irrigation system
The operating principle of this system is simple. A solar generator could provide electricity for an electric motor pump, which delivers water either directly into irrigation or to an elevated reservoir. The control module with sensor data available to the irrigation system on the difference of threshold limit of soil moisture of the irrigated crops, and the real-time soil moisture. When the soil moisture content of the particular crop is below the permissible limit, the sensors will message to the control system and irrigation system to start the irrigation process until the soil moisture content reaches the desired limit.
Fundamental design criteria for the system include minimum maintenance, maximum reliability as well as resource efficiency. A specific characteristic of this system is the fact that generally a battery back-up is not required. This is an advantage since batteries are maintenance-intensive, costly and need regular replacement.
It is the alteration of energy from sunlight into electricity, directly by using photovoltaics (PV), or indirectly by intense solar power. Solar energy is an abundant source of energy in the world. Photovoltaic is an efficient approach to using solar energy. Solar-powered irrigation can be an appropriate alternative for farmers in the present state of energy disaster automatic system using solar power. The major objective of this system is to advance an irrigation system in the field of agriculture by using solar energy.
Solar drip irrigation system working
The pumps are used for the transport of the water are equipped with solar cells. Solar energy absorbed by the cells is then converted into electrical energy. Most of the traditional pump systems mostly work with a diesel engine or with the local power grid. However, two modes of operations present disadvantages compared to solar pumps.
In many rural areas, particularly in developing and emerging countries, the access to the electricity grid is not always guaranteed. In this case, farmers cannot rely on traditional irrigation methods. Using independent and alternative energy can be a solution for the farmer to secure a safe power source and for the public grid to avoid saturation.
Diesel pumps are more efficient than AC powered pumps as they allow greater flexibility. However, one of the major constraints is that this system relies on fuel availability, added to a greater impact on the environment. Diesel-driven pumps are cheaper than solar-powered pumps but the operating costs are high and depend heavily on the diesel price. In solar-powered systems, it works the other way round, that is, although this system is expensive, the source of energy is free. So, after the amortization period, there are no longer operating costs (only the maintenance costs must be considered). Then, solar pumps turn out to be a viable long term investment.
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Working procedure for solar-powered drip irrigation system components
Solar-powered drip irrigation system provided by the following components;
Pump controller – There are mainly two types of pump controllers. They are inverter and a variable frequency drive (VFD). If an AC solar pump is used, an inverter becomes essential to change the DC from the solar panels into AC. The supported power range of a typical inverter extends from 0.15kW to 55kW, with the higher power inverter used for larger irrigation systems.
The solar panel and inverter should be sized accordingly to accommodate the inrush characteristic of an AC motor. Since the AC pump wants high power at the start, the inverter should be able to handle this extra start-up load. Sometimes a VFD controller is used to ensure that the pump motor obtains proper voltage and current.
Many solar DC pumps want a special controller if they are to be powered directly by PV modules (without batteries). The controller or linear current booster (maximum power point tracker) enables the pump to start and run in low light during a cloudy day, or early morning and evening. With a battery power source, the controller could not be required at all for a DC pump.
Solar panel – Solar panel is to generate energy to run the water pump and the panel has 25years limited warranty. A quarterly manual checkup of the solar module is recommended to eliminate dust and other such substance to ensure maximum power from the module.
The pumps are fitted with motors that get energy from solar PV arrays and the nominal power of a solar module is expressed in peak wattage (Wp). The wattage of solar panels depends on the requirement and motors used. In India, the solar PV arrays having a capacity in the range of 200W to 5kWp are recommended by the government.
Water pump – This is a particularly designed pump to operate at even very low light intensity. On a normal day, the pump can deliver 6500 to 7000litre of water /day during eight hour period.
Maximum Power Point Tracker (MPPT) – The MPPT unit adjusts the variation of the voltage on the solar array to maximize power generation. MPPT is an algorithm that included in charge controllers used for extracting maximum obtainable power from the PV module under certain conditions. The voltage at which the Photovoltaic (PV) module can generate maximum power is called maximum power point (or peak power voltage).
Filters – A disk filter is installed between the pump and irrigation pipes to remove the solids in the water to prevent the drippers from getting clogged. The filter is easy to clean and does not want replacement cartridges.
Fertigator tank – Fertigator tank consists of a five-liter steel tank to dispense fertilizers or chemicals through the drip to the crops.
Drip System – Each particular system was provided with 4000 drip points and drippers are placed at 30cm intervals. The drip line consisted of a self-cleaning device to prevent clogging of drippers.
In addition to the above components, each system is equipped with mounting structures for solar array, and water pump, water pump enclosures, 12m long suction line, 1.25” plastic foot valve, steel support structures for fertigator tank and concrete base for pole mount structures of solar panel, solar water pump, fertigator tank, and filter
The success of solar-powered drip irrigation technology
To increase the cropped area, then solar-powered drip irrigation technology. Analysis of monthly weather data and the average bright sunshine hours (BSH) during the Rabi season is 7 to 9 hours a day, which is sufficient to harness the solar energy for use in agriculture.
Under this system, solar panels were installed near the pond and a nano pump (0.1 hp) was used for lifting water from the farm pond t a tank (1,000-liter capacity) placed at 2.5 m height on a platform. During the day time, water is applied to high-value vegetable crops through drip irrigation by gravity method. The drip system discharge rate was 2.4 liters per hour. The field was mainly divided into different plots; each plot was controlled by a valve, which facilitated crop diversification.
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