Lab Report: Renewable Energy Lighting System Design
Communities around the country as well as around the world are setting sustainable development goals. Twidell and Weir (2006, 2) define sustainable development in general terms as “living, producing and consuming in a manner that meets the needs of the present without compromising the ability of future generations to meet their needs.” Renewable energy sources are critical for sustainability. Renewable sources like wind and sun are different from fossil fuels because intense human labor is not necessary. Renewable resources do not negatively impact the environment which is also an important factor for reaching sustainability goals. Twiddel and Weir (2006, 3) explain that “ecological sustainability” can only be accomplished by expanding supplies of renewable energy and making sure energy is used efficiently.
The purpose of this lab report is to propose a design an outdoor lighting system for use in a small town park where a children’s playground is located. The park would be used more often if the area had lighting in the evening and at night. The wind speed data used was from the Class Weather Station (at a height of 3 meters) for the month of March 2011. The goal of the design is to provide enough energy for a minimum of 800 lumens of light. In order to make sure the project is cost effective the turbine and all the necessary support equipment needs to have at least a ten-year lifetime. The park has very little budget for maintenance so the end result should require only a minimum of annual maintenance.
The NegMicon wind turbine with a 60 m diameter rotor has been a standby in the industry since it was produced in 1997. (IPS, 2011) A Horizontal Axis Wind Turbine (HAWT) is athe suitable style for this project. (See fig. 1) The wind strikes the back of the blade and the rotor allows the blade component to move (pitch). (See fig 2) The diameter of the rotor determines the amount of energy created. The rotor sits at the base of the blade component (top left). The low speed shaft connects to the rotor and the gear box. The gear is connected to the high-speed shaft which holds the generator. A controller is computerized and has control of the anemometer and wind vane as it also collects data. The schematic on the right shows an exterior view of the yaw component which is located between the nacelle and the tower components of the wind turbine construction. The yaw drive is located within the top of the tower base and a yaw motor allows for control of the yaw movement – the purpose of the yaw is to provide the optimal amount of energy generation. (See fig. 2) The size of a turbine depends on the location, wind speed, air pressure, density and meteorological and structural factors. Wind turbines are located both onshore and offshore.
Figure 1 Dedicated up tower NegMicon
(IPS Wind Service Data sheet, 2011) (See Appendix)
Figure 2 Diagram of the interior construction of contemporary HAWT, three bladed (left)
and schematic of the exterior (right
(Office of Energy Efficiency and Renewable Energy, 2006 (left)
and Hanuman Wind, 2009 (right))
Figure 2 is a diagram of the interior construction of a three bladed HAWT. Note that the Wind direction is denoted by the thick blue areas. The placement of the turbine must be chosen on the basis of wind direction; it can be placed upwind or downwind for optimum potential results.
Figure 3 Very large turbine’s gear box, rotor shaft and brake assembly being mounted
(Source geograph.org.uk 2008; photo by Paul Andersen 2008)
Figure 3 is a photo of a 12-ton gearbox and disk brake assembly being placed into position 60 meters above ground. The gearbox is being lifted and placed into position by a crane. The crane operator and the engineer in charge have to use radio communications to make sure the gearbox was placed correctly.
The choice of tower height can be crucial to whether or not the most wind power is being accessed for energy. “Power in wind is proportional to the cube of the wind speed; the economic impact of even modest increases in wind speed can be significant” (Masters 2004, 319). The section of air near the surface is affected by air friction because of the obstacles on the earth’s surface; whereas “a calm sea offer(s) very little resistance” (Masters, 2004, 319) The proposed lighting project using wind energy is in a small a town in a park with a few tall trees but mostly shrubs and hedges. Therefore the Friction Coefficient, α, would be expected to be about 0.30. (Masters, 2004, 320) The Friction Coefficient influences the amount of stress on the rotor. This preliminary project assumes the Friction Coefficient to be zero because the first goal is to decide if the park is suitable for wind turbine energy for lighting purposes. The project will be initially designed with a 3.05 meter (10 feet) because the sample weather data was taken at that height.
Rayleigh wind statistics theory and equations have been used to evaluate the data available for the project. Figure 4 shows the graphs of two types of data. The curved line showing a Bell curve distribution is the Raleigh probability in percent; the peak falls at approximately 5 m/s. The second graph is from weather data from Altamont Pass, California. Natural wind speed occurring over time is more random. Notice that the Rayleigh average probability density function, ͞v equals 6.4 m/s or 14.3 mph falls parallel to the probability density functions (note the arrows) at Altamont Pass. (Masters, 2004, 345)
Figure 4 Percent probability versus wind speed v (m/s)
(Masters, 2004, 345)
Figure 4 shows two graphs laid on top of one another in order to depict the Rayleigh probability density function (theoretical) and the weather data from the Altamont Pass, California weather station (real data).
Masters (2004, 350) explains “reasonable assumptions of the overall conversion efficiency into electricity into electricity by the turbine” the amount of wind converted to energy can be estimated in terms of annual energy made available. Masters (2004, 350) also explains that the “highest efficiency possible for the rotor itself is 59.3 percent.” Figure 5 depicts hours per year wind speed versus wind speed (m/s). The shape of the graph is the same as that of the velocity probability density function graph. (See figures 5 and 6)
Figure 5 Ideal conditions for a wind turbine (Masters, 2004, 340)
Figure 5 is a graph created from v (m/s) versus hours per year in histogram form. The hours per year that the wind is traveling at a certain speed are depicted. (Masters, 2004, 340)
Figure 6 Wind speed probability density function
(Masters, 2004, 342)
Figure 6 defines the areas under the curve that is produced by the probability density curve. The average wind speed is not at the peak but to the right of the peak. The velocity (in whatever chosen units) increases from the x/y intersection onwards.
The Capacity Factor can be used to calculate the energy output.
The site selected for the proposed lighting project is the playground area in a small park. The park is in a Class 3 wind power region in the northeastern New Mexico. Tall trees are in the region but shrubs and bushes are interspersed with flowers in the playground area.
The Classroom weather station data were used for graphing and calculating the following information.
The data in Table 1 on the left was used to construct the graph of total number of hours per month at each wind speed on the right. (Figure 8)
749 data measurements were taken in hourly sampling events at a hub height of 3 meters during March 2011. Wind measurements were taken hourly. The data from each day was averaged in order to calculate the Capacity Factor. The average wind speed for March 2011 was calculated to be 11.5 MPH.
Figure 8 Whisper 500 Output, function of wind speed
Figure 8 is a graph of the power output I Watts versus the instantaneous wind speed in mph and m/s.
The wind speed data from the NM Classroom weather station fits fairly well to the output of the Whisper 500 output but the average speed depicted in the graph 13.5 mph. Therefore a smaller model of Whisper wind turbine was found to be more suitable for this project.
Capacity Factor. The Capacity Factor was then calculated in order to calculate the energy needs.
CF = 0.0887 ͞v – PR / D2 (Rayleigh Winds) (Eqn. 1)
CF = Capacity Factor
͞v – velocity (wind speed) (m/s or MPH)
PR = Rated Power (kW)
D2 = Diameter of the wind turbines rotor (m2)
Figure 9 Capacity factor from Average daily wind speed data, March 2011 (Weather Station Data File
Figure 9 shows the resulting linear graph that resulted from the Classroom data. R2 equals 1 so the data has an excellent fit to the slope.
The resulting graph of the Calculated Capacity Factor versus the Daily Average Wind Speed for March 2011 is shown in figure 9 where the slope (y) = 0.087x -0.278. Therefore
CF = 0.087 ͞V - (PR/D2) = 0.087 ͞V – 0.278 (Eqn. 2)
In order to calculate the energy value from the CF equation the specifications of the wind turbine had to be added to the equation.
The energy output for a full year using the Whisper 900 for 24 hours each day for 1 year would be equal to 3526 kWh/y assuming 11.5 MPH average monthly wind speed. (See eqn. 5) The energy output for a full year using the Whisper 900 for 12 hours each day for 1 year would be equal to 1682 kWh/y assuming 11.5 MPH average monthly wind speed. (See eqn. 6)
Energy = (8760) (0.9) (0.413) = 3256 kWh/yr (Eqn. 5)
Energy = (4380) (0.9) (0.413) = 1682 kWh/yr (Eqn. 6)
The Whisper .9 with a 2.13 meter rotor radius was found to the best fit for the projects needs after comparing and contrasting the wind turbines listed in Table 3. The full specification data sheet for the Whisper Wind Turbine H900/2.13 was found online. (See appendix)
Figure 10 Types of lighting coverage (Recommendations, 2010, 6)
Figure 10 shows the five types of lighting coverage from street lamps.
Type III lighting coverage from the street lamps was chosen because there is little to no light leak into neighboring yards. (See fig. 10) Figure 11 depicts diagrams of illumination coverage to illustrate the coverage of Lateral Type III lighting. A vertical coverage of short was chosen so that the forward illumination would equal 63.9 percent, the backward illumination would equal 36.1 percent of the lighting coverage and there would be no upward illumination. Maginess (2012, 11)r recommends 30 to 55 fc of domestic Light for casual reading and 50 to 100 fc for Work Area Light when average reading is required; so 55 fc were chosen and an optimum pole height of 10 feet. The Assist calculator reported the light loss factor under these parameters to be 0.2, the number of luminaires per pole should be 1 and the LSAE at optimum pole height would equal 6.44 lm/W.
Input power: 170 Watts
Candela Multiplier: 10
Distribution types – Lateral: Type III
Vertical – Short
Forward Illumination 63.9%
Backward Illumination 36.1% of total
Upward Illumination – 0.00% of total
Figure 11 Illumination diagrams and assumptions used
Basic parameters 0.2 fc to 4fc
[Recommended Domestic Light level for casual reading requires 30 to 55 fc. (Maginness, 2012, 11) Recommended Work Area Light level for average reading requires 50 to 100 fc. (Maginness, 2012, 11)]
Light loss factor 0.2
Optimum pole height: 3.05 meters (10 feet)
LSAE at optimum pole height: 6.44 lm/W
Figure 12 is a graph of the Luminaire System Application Efficacy (LSAE) in lm/W when the pole height for the street lighting equals 10 feet (mounting height). LSAE is a measurement of the Watts necessary to project the luminous flux to the area desired. If the LSAE can be optimized the amount of energy efficiency will automatically be optimized (Assist 2012)
Figure 12 Luminaire System Application Efficacy in lm/W at 3.05 meters (10.0 feet)
Figure 12 is a graph of the distribution of luminaires per Watt from a 10 foot high mounting hub.
Luminaire system application Efficacy at desire pole height
Luminaire System Application Efficacy (LSAE) 6.44 lm/W
Estimated longitudinal spacing 50.0 feet (15.2 meters)
Estimated transversal spacing 37.5 feet (11.4 meters)
Average illuminance in areas 2.58 fc (27.8 lx)
Average power density 0.0907 W/ft2 (0976 W/m2)
Figure 13 Lighting at ground level on pavement
Figure 13 is a visual representation of the amount of light reaching and reflected from the pavement under the street lamp during the night. (Assist 2012) The amount of light coverage does not fall outside the mesopic light area. (www.lrc.rpi 2013) Mesopic light is the considered the usual light level luminances from about 0.0001to 3 cd m-2. In fact outdoors and traffic lighting during the night are in the mesopic range. (www.lrc.rpi 2013)
Life cycle costs for 365 days a year for 12 hours per day.
Lumanaire price $1000
Initial installation cost per pole (including parts and labor) $500
Lamp life (hours) 10,000
Hours of operation per day 12
Lamp replacement cost including parts labor $200
Electricity cost 10¢ / kWh
Annual interest rate 5%
Life cycle cost per pole $5,003
Average life cycle cost $2.67 / ft2 ($287 / m2)
Prices are the prices from Luminaire http://www.lrc.rpi.edu/parkinglot/#step2
Equipment and circuit drawings
Figure 14 Whisper Wind Turbine and charge controllers (Brother 2013)
Figure 14 displays two photos from the Brother Brennan Centre in New Foundland. On the left is a photo of one of their two Whisper 500 Wind Turbines. On the right is a photo of the “Charge controllers for the wind turbines (diversion resistors on top, on bottom; brake, diversion switch and battery key switch” (Brothers 2013)
Figure 15 Batteries to input and save the energy from the wind turbine
Figure 15 depicts one of the battery arrays used to store energy created by the wind turbines at the Brother Brenna Center.
Figure 16 Typical Electrical layout (European, 2011, 67)
Figure 16 depicts a schematic for a typical electrical wind turbine project. Notice at the top right the existing grid is pointed out. The best position for the electrical equipment is near the grid in case the batteries storing the wind energy have no energy.
The layout in Figure 16 could work well for the park. A wind turbine is situated in the center and a connection to other wind turbines is noted as they are to the east. Meanwhile using the first wind turbine as an example there are two points of common coupling along the HV cable at both the east and the west side of the turbine. The HV/MV transformer substation is located next to the turbine on the north side. all the wind turbines are connected to transformers which are ‘fuse protected’. (See fig. 16) Figure 14 shows the Brother Brennan Centre’s substation with the electrical components.
Figure 17 Whisper 900 turbines behind the Brother Brennan Center, California
(Source Brother Brennan Environmental Centre, 2013)
In conclusion in order to meet the needs of a park playground of approximately 50 m2 it is suggest that eleven wind turbines be used for street lamps with 15 W LEDs. The small Whisper 170 W/ 2.13 m diameter rotor turbines could work well. The Capacity Factor for the Whisper was calculated to be 0.413 which gave a Energy output value of 1682 kWh/y for 12 hours of use each day. A Type III lighting distribution should be satisfactory for park coverage without light leakage into homes along the perimeter. Costs for a street lighting system from Luminaire would cost about $1500 for initial installation. The life cycle cost per pole were estimated to be $5003.
Boyle, G. (ed) (2012)Renewable Energy (3rd Edition), Oxford University Press, 470pp.
Boyle, G.(2012) ‘Solar Photovoltaics’, in Boyle, G.(ed) Renewable Energy (3rd Edition), Oxford University Press, pp. 307 – 383.
Brother Brennan Centre. (2013) “Renewable Energy System: User Manual” Environmental Education Commission, St. Johns, New Foundland Canada http://www.brotherbrennancentre.ca
CIE Publication No. 41. Light as a true visual quantity: principles of measurement. 1978. http://www.cie.co.at/Publications/index.php?i_ca_id=318, 1978. Web. 25 July 2012
European Communities (2001) “Wind Energy: The Facts” Official Journal of the European Communities, www.ewea.org/fileadmin/ewea_documents//Facts_Summary.pdf 27 Oct. 2001. Web. 25 July 2012.
Maginnes, M. (2012) “Lighting your layout”, Presentation v. 1.9d, Seattle 2012 32nd National Narrow Gauge Convention, NNGC Bellevue WA. http://www.4dpnr.org/articles/Layout_Room_Lighting.pdf 2012. 27 Oct. 2001. Web. 25 July 2012.
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“Recommendations for Evaluating Parking Lot Luminaires” (2010) Alliance for Solid-State Illumination Systems and Technology (ASSIST), Lighting Research Center, Rensselaer 7(3) http://www.lrc.rpi.edu/programs/solidstate/assist/recommends.asp January 2010. 27 Oct. 2001. Web. 25 July 2012.
Southwest Wind Power. (2013) http://www.altestore.com/store/Alternative-Energy-Products/501W-TO-1kW-Wind-Turbine/Southwest-Wind-Power-WHISPER-H40-900W-12-48V-Wind-Turbine/p3576/ 31 July 2013 27 Oct. 2001. Web. 25 July 2012.
Twidell, J. and Weir, A. (2006) Renewable Energy Resources, (2nd ed.), London: E.F. and F. Spon.
Appendix 1. Data Sheet for NegMicon Wind Turbines (IPS Wind Services 2011)
Appendix 2. The wind turbine power specification examples from Masters (2004, 364)
Appendix 3 Example from Masters (2004, 365) for total energy produced at 6 m/s wind speed
Appendix 4 Whisper wind turbine specifications
Appendix 4 continued
Appendix 4 continued
Appendix 4 continued
Appendix 5 Detailed wind turbine system diagram for Brother Brennan’s Center
Brother Brennan Center