Alternative Energy Sources Objectives Types
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1 Alternative Energy Sources Objectives • Learn the different type of alternative energy sources available for buildings • Realize important factors that will assist in determining if alternative energy should be used on a site Types • Renewable Energy Source – Solar panels – Wind turbines – Solar water heating systems
Transcript of Alternative Energy Sources Objectives Types
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Alternative Energy Sources
Objectives
• Learn the different type of alternative energy sources available for buildings
• Realize important factors that will assist in determining if alternative energy should be used on a site
Types
• Renewable Energy Source– Solar panels
– Wind turbines
– Solar water heating systems
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Who can use solar energy?
• Two major uses– Direct thermal conversion (sunlight to heat)
– Electrical, or photovoltaic, conversion (sunlight to electrical energy)
• Must control large enough, unobstructed area
How much solar energy is available?
• Can’t plan a system without reasonable expectations
• Gov’t labs have great data for free – much less localized than wind resource data
• For critical applications, multi-year simulations are available
• Software used commercially
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Solar Panels for Electricity Generation (PV)
Solar Panel Terminology
• Power Output – Power (watts) available at the power regulator,
specified usually as peak power under standard conditions
• Energy Output– The energy (watt-hour or Wh) output. This indicates
the amount of energy produced (i.e. converted from solar energy) during a certain period of time
• Conversion Efficiency– This parameter is defined as "energy output from
array" / "energy input from sun" x 100%
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Photovoltaic Systems
• Cell = solid state no moving parts long lasting
• Module = multiple cells = 1 panel– 250W/panel
• Array = multiple panels
• 12-15% efficient
Cell Materials: Silicon based
Nanosolar
Solar Panels
• Connection to structure
• Facing 0 azimuth
• Latitude tilt from horizontal plane
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From National Renewable Energy Laboratory, SolarRadiation Data Manual for Flat Plate & Concentrating Collectors
Photovoltaic grid-tie system
Florida Solar Energy Center
PV string combiner box
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Conversion to something useful
• Direct connection
• Battery chargers
• Inverters – DC to “house current”
Solar Panels Example
• 40 kWh/day system
• Compare size difference needed with;– Fixed tilt at latitude
– 1-axis tracking at latitude
– 2-axis tracking at latitude
More Information
• www.energystar.gov
• www.dsireusa.org
• Dept of Energy www.eere.energy.gov
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Solar water heating
Source: US DOE
Solar Hot Water System
• About 20% of total energy usage
• Need abundance of sunny days
• Save 10% on home utility bill
• 40-80% efficient
www.eere.energy.gov
Example: simple energy replacement
• Considering a simple water heating collector with advertised efficiency of 50%
• Central IL has annual solar availability of 4.7 kWh/day-m2
• Replacing $1/therm natural gas
• Therm = 99,976 BTU
• 293 kWh = 1 MBTU
• Simple payback 7 years?
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More Information
• International standards: ISO 9806 Test Methods for Solar Collectors (Glazed water heating)
• Florida Solar Energy Center www.fsec.ucf.edu
Wind Turbines
• Great energy source in central IL
• High speed turbines = 45% efficient
Wind Turbines
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Wind Turbines
Wind Turbines
Wind Turbines
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Wind Turbines
• Possible zoning ordinances– Lighting
– Appearance & Color
– Signs
– Access to Tower
– Setbacks
– Code Compliance
Wind Turbines
• Concerns– Lot size
– Multiple turbines
– Sound
Wind Turbine Power Calculations
• P = 0.5 x ρ x A x Cp x V3 x Ng x Nb
• where:P = power in watts (746 watts = 1 hp) (1,000 watts = 1 kilowatt)ρ = air density (about 1.225 kg/m3 at sea level, less higher up)A = rotor swept area, exposed to the wind (m2)Cp = Coefficient of performance (.59 {Betz limit} is the maximum theoretically possible, .35 for a good design) V = wind speed in meters/sec (20 mph = 9 m/s)Ng = generator efficiency (50% for car alternator, 80% or possibly more for a permanent magnet generator or grid-connected induction generator)Nb = gearbox/bearings efficiency (depends, could be as high as 95% if good)
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Wind Turbine Example
• Yearly output for 15’ diameter turbine in central Illinois. Use typical assumptions.
Power Uses
• Stand Alone – systems with no connection to utility grid
• Battery source – connected to battery for power storage
• Net Metering – Connected to Utility. Use power from renewable source first. Sell off any extra. Buy any extra needed. Sell at whole sale buy at retail.
Federal Incentive
• Solar panels = 30% of cost
• Wind Turbines = 30% of cost
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More Information
• American Wind Energy Organization www.awea.org
• Dept of Energy http://www1.eere.energy.gov/windandhydro/
