October 12th, 2012 | Published in Thesis Methodology
This chapter refers to the theoretical analysis of the method appropriate to a pico hydro field of study or to the body of methods and principle particular to a branch of knowledge.
It is nothing more than a simple set of methods or procedure, or it may refer to the rationale and the philosophical assumption that underlie a particular study relative to the scientific method. Specifically, this chapter includes the Gantt chart, flow chart and the scope of work of the project study.
4.1 Gantt chart
4.1.1 Pico hydro system planning
This stage is the most critical stage in this project as it determines the feasibility and achievement of water available from the water flow inside the penstock, used turbine and generator type and capacity, capacity of electrical load to be supplied by the pico hydro system and the cost of developing the project and operating the system.
4.1.2 Site Selection
There are thousands of sites where people have a source of falling but do not have electricity. For these rural communities, pico hydro is the lowest cost technology for generating electricity. Lighting from this source is cheaper than using kerosene lamps, and safer too. There are three basic types of location which are suitable for conducting a study regarding the energy potential of available in Maluya Central, Balanga City, Bataan is suitable for the implantation of the study regarding the generation of electrical energy.
Pico hydro power generate a limited power, because of that, is oriented to reduced application as small grid or individual use. According to this, to avoid high grid expenses and power losses, the site should not be too far from end users. As a standard for 1 kw of power, the distance should not be more than 2km in this project, the distance if the site into the end user is 150m obtaining 240W which is appropriate for the study.
4.1.3 Measuring Flow
The flow of water in a river should be enough throughout a year, extreme flows can affect to the system performance, and the excess flow must be controlled. The measurement of the flow should be at least be done twice a year, during the lowest season (February- May) ad also in the highest season (end of September – beginning of October.
The flow of water on the desired locations was determined using practical methods. The water flow can be located approximately by knowing the water speed. By dropping a left upstream and reading the time it takes to travel the measured distance. This practical approach of measuring the speed of water is done exactly 15 times.
4.1.4 Testing and set up
This includes set up and of pico hydro to chosen site in sitio catmon, diwa, pilar, bataan. Pico hydro set up typically are run of stream, meaning that dams are not used , but rather pipes divert some of the flow, drop this down a gradient, and through the turbine before being exhausted back to the stream.
The two vital factors to consider are the flow and the head of the stream or river. The flow is the volume of water which can be captured and redirected to run the turbine generator, and the head is the distance the water will fall its way to the generator.
4.2 Flow chart
A flow chart shows the step by step process represent in boxes of various kinds, and their order by connecting these with arrows, this diagrammatic representation can give a step by step solution to a given problem. The process is stared with the selection of topic data, data gathering and data analysis, site investigation, canvassing of materials for the design, fabrication, measurement and calculation of the parameters present at the site, testing of the system and troubleshooting. But if there is a point in a process wherein an error takes place, it is necessary to go back to troubleshooting, design and calculation of parameters.
4.3 Input parameters
Flow rate – amount of water that flows that passes the turbine in a given time, measure in the liter/second.
Head – the height of water surface flowing into the turbine down to the water surface below, measure in m(m), inches (in), of feet (ft)
Hydraulic pressure – relationship between the force you apply and the result you get. It is the way a liquid acts in a closed system of pipes and cylinder. The action of liquid under such condition is somewhat different from its behavior in open container or in lakes, rivers, or ocean. You cannot compress most liquid into a smaller space. Liquid don’t give the way air when you apply pressure, nor do liquids expand when you removed pressure.
4.4 Output parameters
Electric power – amount of work done by an electric current in a unit time. It is considered a rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt. When electric current flows in a circuit, it can transfer energy to do mechanical or thermodynamic work. Devices convert electrical energy into many useful forms such as heat (electric heater), light (light bulbs), motion (electrical motors) and sound (loudspeaker).
Power house – the rate at which electrical energy is transferred by a circuit. In physics, it is the rate at which work is performed or energy is converted.
Voltage – it is commonly used as a short name for electrical potential difference. The voltage between two points is a short name for the electrical driving force that could determine an electric current between those points. Basically, it is equal to energy per unit charge.
Electric potential energy – potential energy can be defined as the capacity for doing work arises from position or configuration. In the electrical case, a charge will exert a force on any other charge and potential energy arises from any collection of charges. It is also a potential energy associated with the conservative coulomb forces within a defined system of point charges.
Ampere – in practical terms, it is a measure of the amount of electric charge passing a point per unit time. Around 6.24 x 10 to the 18 electrons or coulomb passing a given point each second constitutes one ampere.
4.5 Water source and energy potential
A run of river has been chosen for the pico hydro system due to the fact that it has a high head, suitable flow rate, and is conveniently located near the main. Although the stream is being used for irrigation, there are decreasing occurrences of drop failure due to having intensive irrigation schemes for the execution of the supply of water.
All measurements were taken during the dry season (late January). Using the float method, the flow of the river was determined to be around 0..35 m3 (351/s). Effectively, this is the amount of water not currently being used by the community. Practically, it would be possible to utilize the entire 35 1/s flow since it is a run of river scheme in which all water will be returned to the stream.
The available head and flow is enough to provide for the energy needs of one household. As such, there is range of possibilities for the combination of head and flows that would be sufficient for the system. The final decision was determined based on the most convenient location for civil works and the power source.
A proposed location for the intake was along the river. This provides a gross head of 1m between the penstock intake and the powerhouse based on the requirement of the turbine, a flow rate of between 12 and 15 liters/s will be used (approximately 45% of the low season flow). This will ensure the required flow is available year round, in addition to preserving the aesthetic quality of the waterfall.
4.6 Civil works
Since the stream has more than flow to power the system even during the dry season, only a low level of civil works will be required. A small collection area was submerged. Although there is limited amount of sediment in the stream, the collection area will also allow any sediment to settle before entering the intake. To further ensure the intake is submerged during the dry season, a small diversion could be constructed on the shelf using stone and mortar.
4.7 Transmission lines
The household is located 100 meter from the proposed power source, which will be required 50 meters of transmission cable 3.5 mm2 cooper wire THWN/THHN service drop wire was in connecting transmission and is locally available and suitable for a 118W system.
Excerpt from the Project Study for Rural Electrification by Jerome dela Cruz, Kenneth Aquino, Wilgem Regino Crespo, John Andrew Molino and Rosauro Fernando Jr of BPSU.