Making the solar panel based water pump highly portable and theft free we introduce an idea of using hinge or clamp between the panels so that they can be easily detached while carrying them to the field and then assembling them there only to use them as a power providing source on the field.
The frame on which the whole solar panel system is to be placed should be installed firmly on the field and we just have to put the whole setup of panels on that frame by connecting them with the hinge to make them stable on it and then connecting them either in series or parallel as per the requirement of current or voltage to drive the water pump so that water is stored in storage tank.
Considering the idea, we can use two concept of connecting either 3 panels or 6 panels as shown in the figure uploaded.
The highlight and benefit of this idea is that due to this clamping arrangement of panel a farmer can easily dissemble them when not in use and carry them easily on a bullock cart or even on small tricycle or bicycle from his field to the house to avoid theft or any kind of damage to the panels and when he requires to irrigate the field he can easily assemble them and connect the pump to the controller board to run the pump on the available solar energy keeping the environment green and pollution free.
Second benefit of this idea is it requires less maintenance cost and durability is very high. It is also a very simple design to implement and have robust construction. The whole cost of this idea is within the reach of an Indian farmer and it suites the climatic as well as the economic condition of a typical farmer who lives in India.
1. DESIGN PROCESS
The following twelve steps can be used in the design process for a PV-powered water pump system. These steps will help us ensure that the system functions properly and that water is supplied for the operation in the amounts and at the locations required.
1.0 Step 1 – Water Requirement
The first step in designing a solar-powered water pump system is to determine the overall water requirement for the operation. This can be done in part by using the average water requirement values for various crops and livestock.
1.1 Step 2 – Water Source
The configuration of the water system will be defined primarily by the type of water source used, as well as by the local topography and the location(s) of the delivery point(s). The water source may be either subsurface (a well) or surface (a pond, stream, or spring).
If the water source is a well, the following items will need to be determined:
• The static water level,
• The pumping rate and associated drawdown (along with any seasonal variation), and
• The water quality.
The drawdown value obtained from the well log should be used to determine the production potential of the well to ensure that the well will be able to supply the operation’s estimated water needs. If the well log indicates an excessive drawdown during the given testing time, the well may not have the capacity to meet the water demands of the project. If the capacity of the well is in question, a complete well test should be performed and the drawdown levels measured for different flow rates.
In addition, the drawdown level should be used when determining the pumping lift and TDH during pumping
If a new well is to be drilled for the project, information from well logs of existing, nearby wells can provide valuable information about the subsurface hydrology in the area and the potential yield of the proposed well. Records of well logs are available online from the Oregon Water Resources Department (WRD).
The expected pumping levels should be determined in areas where water table fluctuations occur throughout the year. In such areas, a well may even run dry at certain times of the year. An alternate water source should be located if there is a potential for an existing well to run dry during critical watering times.
For most wells, water quality is not an issue if the water is not used for human consumption. However, it is a good practice to obtain a water quality test if there is a potential for fecal coliform contamination, high nitrates or salinity, organic contaminants, and/or the presence of heavy metals, which may be the case for wells located in unique geological features, such as volcanic terrain.
For surface water sources, such as a stream, pond, or spring, the following need to be determined, taking seasonal variations into account:
• The water availability,
• The pumping levels, and
• The water quality, including the presence of silt and organic debris.
With a surface source, the water availability and water level can vary seasonally. In particular, the amount and quality of the water may be low during the summer, when it is needed most.
Additionally, when a surface water source is used, proper screening of the pump intake is necessary to ensure that debris and sediment from the surface water body are not pumped into the system.
1.2 Step 3 – System Layout
The third step in the system development process is to determine the layout of the entire system, including the locations and elevations of the following components:
• Water source
• PV panels
• Storage tanks
• Points of use (i.e. water troughs)
• Pipeline routes
It is also important to consider potential vandalism and theft when locating PV panels and pump systems. Unfortunately, since most solar panel systems are located in remote areas on open landscapes, the risk of vandalism and/or theft can be significant. If possible, panels, tanks, and controllers should be located away from roads and public access, as well as where features in the landscape (rolling hills, escarpments, wind blocks, etc.) can provide a maximum of shielding from public view. The use of trees, bushes, or other types of vegetation for shielding is acceptable. However, care should be taken to situate the panels far enough to the south and west of tall trees and other types of vegetation to reduce the potential for their obstruction by shadows during peak solar insolation hours.
In addition, secure fencing is essential to protect a PV-powered system. Secure fencing provides added protection against vandalism and theft, as well as against inadvertent damage from wandering wildlife or livestock.
1.3 Step 4 – Water Storage
A water storage tank is normally an essential element in an economically viable solar-powered water pump system. A tank can be used to store enough water during peak energy production to meet water needs in the event of cloudy weather or maintenance issues with the power system. Ideally, the tank should be sized to store at least a three-day water supply. Multiple tanks may be required if a very large volume of water is to be stored.
The area where the tank is to be placed must be stripped of all organic material, debris, roots, and sharp objects, such as rocks. The ground should then be leveled. Six inches of well-compacted ¾ -inch leveling rock underlain by a geotextile fabric should be provided as a base for the water tank. If an elevated platform or stand is required to provide adequate gravity-induced pressure for the water delivery system to operate, the platform or stand will need to be evaluated by a qualified engineer.
An above-ground tank should be constructed out of structurally sound, UV-resistant material to maximize its lifespan. If it will be used in areas where freezing temperatures are encountered, care should be taken to frost-proof the entire water delivery system. Tanks and pipes should be drained prior to the first freeze, and pipes should be buried below the frost line for added protection.
A buried tank is naturally shielded from UV light, and it provides protection from frost and vandalism. When using a buried tank, however, adequate drainage must be provided around the tank. In addition, its design must be analyzed for floatation to ensure that the tank will not become buoyant.
1.4 Step 5 – Solar Insolation and PV Panel
Appropriate data should be used to determine the amount of solar insolation (peak sun hours) available at the site.
In order to maximize the solar-powered system’s energy production, the panels should be south facing with no significant shading in their vicinity in order to achieve full sun exposure. However, partial shading (e.g., shadows from tall trees) in the distance during the early morning or late afternoon may be unavoidable. The effects of any shading present should be considered when determining the amount of available solar energy. Also consider the potential effects that the slope and aspect of future shading due to continued tree growth may have.
The solar array should be placed as close to the pump as possible to minimize the electric wire length (and thus any energy loss), as well as installation costs.
1.5 Step 6 – Design Flow Rate for the Pump
The design flow rate for the pump is calculated by dividing the daily water needs of the operation by the number of peak sun hours per day. For example, for a daily water requirement of 1,310 gallons/day and a solar insolation value of 7.2 kWh/m2/day, or 7.2 hr/day:
Flow = 1,310 gal/day
= 181 gal/hr
~ = 3 gal/min
1.6 Step 7 – Total Dynamic Head (TDH) for
TDH for a pump is the sum of the vertical lift, pressure head, and friction loss. Friction losses apply only to the piping and appurtenances between the point of intake (inlet) and the point of storage (i.e. the storage tank or pressure tank). Flow from the storage tank to the point of use (i.e. the trough) is typically gravity fed. Therefore, friction losses between the storage tank and the point of use are independent from the pump and do not need to be accounted for when sizing the pump.
1.7 Step 9 – PV Panel Selection and Array
When multiple panels are required, they must be wired in series, parallel, or a combination of series-parallel to meet both the voltage and amperage requirements of the pump.
The power output of the individual panels can be added together to determine the total power they produce.