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| | = '''<span style="font-size: 10pt;">T</span><span lang="EN-US" style="font-size: 10pt;">urbine/Generator</span>''' = | | = '''<span style="font-size: 10pt;">T</span><span lang="EN-US" style="font-size: 10pt;">urbine/Generator</span>''' = |
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| − | '''<u><br></u>'''<u></u>'''<span lang="EN-US" style="font-size: 10pt;">The turbine will extract energy from the flowing</span>''' water, and turn it into mechanical energy that turns the generator to create electrical energy. System efficiencies range between 65% and 80% depending upon the turbine style and design. <o:p></o:p> | + | '''<u><br></u>''''''<span lang="EN-US" style="font-size: 10pt;">The turbine will extract energy from the flowing</span>''' water, and turn it into mechanical energy that turns the generator to create electrical energy. System efficiencies range between 65% and 80% depending upon the turbine style and design. |
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| | + | <br> |
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| | + | = <!--[if gte mso 10]> |
| | + | <style> |
| | + | /* Style Definitions */ |
| | + | table.MsoNormalTable |
| | + | {mso-style-name:"Normale Tabelle"; |
| | + | mso-style-parent:""; |
| | + | font-size:10.0pt;"Times New Roman","serif"; |
| | + | mso-fareast-"Times New Roman";} |
| | + | </style> |
| | + | <![endif]--><!--[if gte mso 9]><xml> |
| | + | |
| | + | </xml><![endif]--><!--[if gte mso 9]><xml> |
| | + | |
| | + | |
| | + | </xml><![endif]--> '''<span>Microhydro-Electric</span> System Types''' = |
| | + | |
| | + | == '''Off-Grid Battery-Based Microhydro-Electric Systems''' == |
| | + | |
| | + | <span>Most small off-grid hydro systems are battery-based. Battery systems have great flexibility and can be |
| | + | combined with other energy sources, such as wind generators and solar-electric |
| | + | arrays, if the stream is seasonal. Because stream flow is usually consistent, |
| | + | battery charging is as well, and it´s often possible to use a relatively small |
| | + | battery bank. Instantaneous demand (watts) will be limited not by the water |
| | + | potential or turbine, but by the size of the inverter.</span> |
| | + | |
| | + | <span>The following illustration includes the primary |
| | + | components of any off-grid battery-based microhydro-electric system..</span> |
| | + | |
| | + | picture... <br> |
| | + | |
| | + | == '''Off-Grid Batteryless Microhydro-Electric Systems''' == |
| | + | |
| | + | <span>If the stream has enough potential, one may decide to |
| | + | go with an AC-direct system. This consists of a turbine generator that produces |
| | + | AC output at 120 or 240 volts, which can be sent directly to standard household |
| | + | loads. The system is controlled by diverting energy in excess of load requirements |
| | + | to dump loads, such as water- or air-heating elements. This technique keeps the |
| | + | total load on the generator constant. A limitation of these systems is that the |
| | + | peak or surge loads cannot exceed the output of the generator, which is |
| | + | determined by the stream´s available head and flow. This type of system needs |
| | + | to be large to meet peak electrical loads, so it can often generate enough |
| | + | energy for all household needs, including water and space heating.</span> |
| | + | |
| | + | <span>The following illustration includes the primary components |
| | + | of any off-grid batteryless microhydro-electric system. </span> |
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| | + | <!--[if gte vml 1]> |
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| | + | <![endif]-->picture .... |
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| | + | <br> |
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| | + | |
| | + | == '''Grid-Tied Batteryless Microhydro-Electric Systems''' == |
| | + | |
| | + | <span>Systems of this type use a turbine and controls to |
| | + | produce electricity that can be fed directly into utility lines. These can use |
| | + | either AC or DC generators. AC systems will use AC generators to sync directly |
| | + | with the grid. An approved interface device is needed to prevent the system |
| | + | from energizing the grid when the grid is out of action and under repair. DC |
| | + | systems will use a specific inverter to convert the output of a DC hydro |
| | + | turbine to grid-synchronous AC. The biggest drawback of batteryless systems is |
| | + | that when the utility is down, your electricity will be out too. When the grid |
| | + | fails, these systems are designed to automatically shut down.</span> |
| | + | |
| | + | <span>The following illustration includes the primary |
| | + | components of any grid-tied batteryless microhydro-electric system. </span> |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
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| | + | <![endif]--> |
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| | + | [[|]]'''<span>Microhydro-Electric</span>''' System Components |
| | + | |
| | + | '''Controls'''<span> |
| | + | </span> |
| | + | |
| | + | AKA: Charge controller, controller, regulator |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|Controller]] |
| | + | |
| | + | |
| | + | |
| | + | <span>The function of a |
| | + | charge controller in a hydro system is equivalent to turning on a load to |
| | + | absorb excess energy. Battery-based microhydro systems require charge |
| | + | controllers to prevent overcharging the batteries. Controllers generally send |
| | + | excess energy to a secondary (dump) load, such as an air or water heater. Unlike |
| | + | a solar-electric controller, a microhydro system controller does not disconnect |
| | + | the turbine from the batteries. This could create voltages that are higher than |
| | + | some components can withstand, or cause the turbine to overspeed, which could result in dangerous |
| | + | and damaging overvoltages.</span> |
| | + | |
| | + | <span>Off-grid, batteryless |
| | + | AC-direct microhydro systems need controls too. A load-control governor |
| | + | monitors the voltage or frequency of the system, and keeps the generator |
| | + | correctly loaded, turning dump-load capacity on and off as the load pattern |
| | + | changes, or mechanically deflects water away from the runner. Grid-tied |
| | + | batteryless AC and DC systems also need controls to protect the system if the |
| | + | utility grid fails.</span> |
| | + | |
| | + | == '''Dump Load''' == |
| | + | |
| | + | AKA: diversion load, shunt load |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|Dump Load 1]]<!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|Dump Load 2]] |
| | + | |
| | + | <span>A dump |
| | + | load is an electrical resistance heater that must be sized to handle the full |
| | + | generating capacity of the microhydro turbine. Dump loads can be air or water |
| | + | heaters, and are activated by the charge controller whenever the batteries or |
| | + | the grid cannot accept the energy being produced, to prevent damage to the |
| | + | system. Excess energy is "shunted" to the dump load when necessary.</span> |
| | + | |
| | + | |
| | + | |
| | + | |
| | + | |
| | + | == '''<span>Battery</span> Bank''' == |
| | + | |
| | + | AKA: storage battery |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|Battery Bank]] |
| | + | |
| | + | <span>By using |
| | + | reversible chemical reactions, a battery bank provides a way to store surplus |
| | + | energy when more is being produced than consumed. When demand increases beyond |
| | + | what is generated, the batteries can be called on to release energy to keep |
| | + | your household loads operating.</span> |
| | + | |
| | + | <span>A |
| | + | microhydro system is typically the most gentle of the RE systems on the |
| | + | batteries, since they do not often remain in a discharged state. The bank can |
| | + | also be smaller than for a wind or PV system. One or two days of storage is |
| | + | usually sufficient. Deep-cycle lead-acid batteries are typically used in these |
| | + | systems. They are cost effective and do not usually account for a large |
| | + | percentage of the system cost.</span> |
| | + | |
| | + | |
| | + | |
| | + | == '''Metering''' == |
| | + | |
| | + | <span>AKA: |
| | + | battery monitor, amp-hour meter, watt-hour meter</span> |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|Metering]] |
| | + | |
| | + | <span>System |
| | + | meters measure and display several different aspects of your |
| | + | microhydro-electric system´s performance and status—tracking how full your |
| | + | battery bank is, how much electricity your turbine is producing or has |
| | + | produced, and how much electricity is being used. Operating your system without |
| | + | metering is like running your car without any gauges—although possible to do, |
| | + | it´s always better to know how well the car is operating and how much fuel is |
| | + | in the tank.</span> |
| | + | |
| | + | |
| | + | |
| | + | [[|]]'''<span>Main DC</span>''' Disconnect |
| | + | |
| | + | == '''AKA: Battery/Inverter disconnect''' == |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|Main DC Disconnect]] |
| | + | |
| | + | <span>In |
| | + | battery-based systems, a disconnect between the batteries and inverter is |
| | + | required. This disconnect is typically a large, DC-rated breaker mounted in a |
| | + | sheet-metal enclosure. It allows the inverter to be disconnected from the |
| | + | batteries for service, and protects the inverter-to-battery wiring against |
| | + | electrical faults.</span> |
| | + | |
| | + | |
| | + | |
| | + | |
| | + | |
| | + | == '''Inverter''' == |
| | + | |
| | + | <span>AKA: DC-to-AC |
| | + | converter </span> |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|Battery-Based Inverter]]<span>Inverters |
| | + | transform the DC electricity stored in your battery bank into AC electricity |
| | + | for powering household appliances. Grid-tied inverters synchronize the system´s |
| | + | output with the utility´s AC electricity, allowing the system to feed |
| | + | hydro-electricity to the utility grid. Battery-based inverters for off-grid or |
| | + | grid-tied systems often include a battery charger, which is capable of charging |
| | + | a battery bank from either the grid or a backup generator if your creek isn´t |
| | + | flowing or your system is down for maintenance.</span> |
| | + | |
| | + | <span>In rare |
| | + | cases, an inverter and battery bank are used with larger, off-grid AC-direct |
| | + | systems to increase power availability. The inverter uses the AC to charge the |
| | + | batteries, and synchronizes with the hydro-electric AC supply to supplement it |
| | + | when demand is greater than the output of the hydro generator.</span> |
| | + | |
| | + | [[|]]'''<span>AC</span>''' Breaker Panel |
| | + | |
| | + | AKA: mains panel, breaker box, service entrance |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|AC Breaker Panel]] |
| | + | |
| | + | <span>The AC |
| | + | breaker panel, or mains panel, is the point at which all of a home´s electrical |
| | + | wiring meets with the provider of the electricity, whether that´s the grid or a |
| | + | microhydro-electric system. This wall-mounted panel or box is usually installed |
| | + | in a utility room, basement, garage, or on the exterior of a building. It |
| | + | contains a number of labeled circuit breakers that route electricity to the various |
| | + | rooms throughout a house. These breakers allow electricity to be disconnected |
| | + | for servicing, and also protect the building´s wiring against electrical fires.</span> |
| | + | |
| | + | <span>Just like |
| | + | the electrical circuits in your home or office, a grid-tied inverter´s |
| | + | electrical output needs to be routed through an AC circuit breaker. This |
| | + | breaker is usually mounted inside the building´s mains panel. It enables the |
| | + | inverter to be disconnected from either the grid or from electrical loads if |
| | + | servicing is necessary. The breaker also safeguards the circuit´s electrical |
| | + | wiring.</span> |
| | + | |
| | + | ''' ''' |
| | + | |
| | + | [[|]]'''Kilowatt-Hour Meter''' |
| | + | |
| | + | <span>AKA: KWH |
| | + | meter, utility meter</span> |
| | + | |
| | + | <!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:|Kilowatt-Hour Meter]] |
| | + | |
| | + | <span>Most |
| | + | homes with grid-tied microhydro-electric systems will have AC electricity both |
| | + | coming from and going to the utility grid. A multichannel KWH meter keeps track |
| | + | of how much grid electricity you´re using and how much your RE system is |
| | + | producing. The utility company often provides intertie-capable meters at no |
| | + | cost.</span> |
| | + | |
| | + | ''' ''' |
| | + | |
| | + | ''' ''' |
| | + | |
| | + | ''' ''' |
| | + | |
| | + | ''' ''' |
| | + | |
| | + | ''' ''' |
| | + | |
| | + | ''' ''' |
| | + | |
| | + | == ''''Turbines'types''' == |
| | + | |
| | + | <span><!--[if gte vml 1]> |
| | + | |
| | + | |
| | + | <![endif]-->[[Image:]]</span> |
| | + | |
| | + | <span>A turbine converts the energy in |
| | + | falling water into shaft power. There are various types of turbine which can be |
| | + | categorised in one of several ways. The choice of turbine will depend mainly on |
| | + | the pressure head available and the design flow for the proposed hydropower |
| | + | installation. As shown in table 2 below, turbines are broadly divided into |
| | + | three groups; high, medium and low head, and into two categories: impulse and |
| | + | reaction. </span> |
| | + | |
| | + | {| cellpadding="0" border="1" |
| | + | |- |
| | + | | valign="top" align="center" colspan="4" | |
| | + | '''<span>Head</span> ''' |
| | + | |
| | + | '''pressure''' |
| | + | |
| | + | |- |
| | + | | valign="top" | |
| | + | '''<span>Turbine</span> ''' |
| | + | |
| | + | '''Runner''' |
| | + | |
| | + | | valign="top" align="center" | |
| | + | '''High''' |
| | + | |
| | + | | valign="top" align="center" | |
| | + | '''Medium''' |
| | + | |
| | + | | valign="top" align="center" | |
| | + | '''Low''' |
| | + | |
| | + | |- |
| | + | | valign="top" | |
| | + | Impulse |
| | + | |
| | + | | valign="top" | |
| | + | <span>Pelton |
| | + | </span> |
| | + | |
| | + | Turgo |
| | + | |
| | + | Multi-jet Pelton <br> |
| | + | |
| | + | | valign="top" | |
| | + | <span>Crossflow |
| | + | </span> |
| | + | |
| | + | Turgo |
| | + | |
| | + | Multi-jet Pelton <br> |
| | + | |
| | + | | valign="top" | |
| | + | Crossflow |
| | + | |
| | + | |- |
| | + | | valign="top" | |
| | + | Reaction |
| | + | |
| | + | | valign="top" | |
| | + | <span>Francis |
| | + | </span> |
| | + | |
| | + | Pump-as-turbine (PAT) <br> |
| | + | |
| | + | | valign="top" | |
| | + | <span>Propeller |
| | + | </span> |
| | + | |
| | + | Kaplan <br> |
| | + | |
| | + | | valign="top" | |
| | + | |
| | + | |
| | + | |} |
| | + | |
| | + | ''' ''' |
| | + | |
| | + | <span>The difference between impulse and |
| | + | reaction can be explained simply by stating that the ''impulse'' turbines |
| | + | convert the kinetic energy of a jet of water in air into movement by striking |
| | + | turbine buckets or blades - there is no pressure reduction as the water |
| | + | pressure is atmospheric on both sides of the impeller. The blades of a ''reaction'' |
| | + | turbine, on the other hand, are totally immersed in the flow of water, and the |
| | + | angular as well as linear momentum of the water is converted into shaft power - |
| | + | the pressure of water leaving the runner is reduced to atmospheric or lower. </span> |
| | + | |
| | + | == '''Load factor''' == |
| | + | |
| | + | <span>The load factor is the amount of |
| | + | power used divided by the amount of power that is available if the turbine were |
| | + | to be used continuously. Unlike technologies relying on costly fuel sources, |
| | + | the 'fuel' for hydropower generation is free and therefore the plant becomes |
| | + | more cost effective if run for a high percentage of the time. If the turbine is |
| | + | only used for domestic lighting in the evenings then the plant factor will be |
| | + | very low. If the turbine provides power for rural industry during the day, |
| | + | meets domestic demand during the evening, and maybe pumps water for irrigation |
| | + | in the evening, then the plant factor will be high. </span> |
| | + | |
| | + | <span>It is very important to ensure a |
| | + | high plant factor if the scheme is to be cost effective and this should be |
| | + | taken into account during the planning stage. Many schemes use a 'dump' load |
| | + | (in conjunction with an electronic load controller - see below), which is |
| | + | effectively a low priority energy demand that can accept surplus energy when an |
| | + | excess is produced e.g. water heating, storage heaters or storage cookers. </span> |
| | + | |
| | + | == '''Load control governors''' == |
| | + | |
| | + | <span>Water turbines, like petrol or |
| | + | diesel engines, will vary in speed as load is applied or relieved. Although not |
| | + | such a great problem with machinery which uses direct shaft power, this speed |
| | + | variation will seriously affect both frequency and voltage output from a |
| | + | generator. Traditionally, complex hydraulic or mechanical speed governors |
| | + | altered flow as the load varied, but more recently an electronic load |
| | + | controller (ELC) has been developed which has increased the simplicity and |
| | + | reliability of modern micro-hydro sets. The ELC prevents speed variations by |
| | + | continuously adding or subtracting an artificial load, so that in effect, the |
| | + | turbine is working permanently under full load. A further benefit is that the |
| | + | ELC has no moving parts, is very reliable and virtually maintenance free. The |
| | + | advent of electronic load control has allowed the introduction of simple and |
| | + | efficient, multi-jet turbines, no longer burdened by expensive hydraulic |
| | + | governors. </span> |
| | | | |
| | [[Category:Hydro]] | | [[Category:Hydro]] |
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