250 likes | 425 Views
Energy Efficiency. Energy Efficiency : Percentage of the total energy input that does useful work and is not converted into LQE. HQE = high-temperature heat and chemical energy in fossil and nuclear fuels - useful
E N D
Energy Efficiency Energy Efficiency: Percentage of the total energy input that does useful work and is not converted into LQE. HQE = high-temperature heat and chemical energy in fossil and nuclear fuels - useful LQE = low-temperature heat that is dispersed or diluted – mostly useless (generally through water vapor/steam) Life Cycle Cost = initial cost + lifetime operating cost. Energy efficient appliances cost more initially, but cost less to maintain and therefore have lower life cycle costs.
ENERGY EFFICIENCY FACTS • 84% of all commercial energy used in the USA is wasted. • People in the USA unnecessarily waste as much energy as 2/3 of the world’s population consumes (more than $300 billion/year). • 43% of the energy wasted is from using “energy inefficient” motor vehicles (especially SUV’s).
WHAT DOES THIS MEAN? Energy Efficiency = Military, Economic, and Environmental Security How do we achieve this? LIFE STYLE CHANGES!
ENERGY EFFICIENCY IN COMMON ENERGY CONVERSION DEVICES Fluorescent Light Bulb 22% Incandescent Light Bulb 5%
ENERGY EFFICIENCY CONTINUED Gasoline Internal Combustion Engine 10%-30% Steam Turbine – used in most power plants 45%
ENERGY EFFICIENCY CONTINUED Coal Combustion = 30 % Efficient
ENERGY EFFICIENCY CONTINUED Nuclear Power = 17 % Efficient With externalities = 8% Efficient Note: The greater the number of steps involved in energy conversion, the lower it’s net efficiency will be.
ENERGY EFFICIENCY IN APPLIANCES • Energy-efficient appliances typically cost more than than less efficient models. • Look for Energy Stars label. • Use appliances during off-peak hours: winter – peak generating costs 4:00 – 8:00 pm summer – peak generating costs 11:00 am – 8:00 pm
OVENS AND RANGES • Gas – 60 % loss in energy, but heat is distributed more evenly. • Electric – 40 % loss in energy. • Ovens that cycle on/off are more efficient. • Self-cleaning ovens have more insulation and retains heat very well - uses a LOT of energy
Appliance Temperature Time Energy Cost* Electric oven 350ºF 1 hr. 2.0 kWh 16¢ Convection Oven 325ºF 45 min. 1.39 kWh 11¢ Gas oven 350ºF 1 hr. 0.112 therm 7¢ Cooktop/fryingpan 420ºF 1 hr. 0.9 kWh 7¢ Toaster oven 425ºF 50 min. 0.095 kWh 8¢ Crockpot 200ºF 7 hrs. 0.7 kWh 6¢ Microwave oven "High" 15 min. 0.36 kWh 3¢ *Cost assumes 8¢/kWh for electricity and 60¢/therm for gas (Source: ACEEE, Consumer Guide to Home Energy Savings, 1999) Comparison table of the energy costs of cooking the same meal by several methods
CLOTHES WASHERS • A considerable amount of hot water is used for washing clothes. Use a machine that uses the fewest gallons of water per pound of clothes and one with H,M & L settings for water level control. • Use appropriate volume of water for load. • Use a low-warm water temperature for washing and cold cycle for rinsing. • Use during off-peak hours. • Follow maintenance instructions and clean regularly.
CLOTHES DRYERS • A dryer evaporates water from clothes and minimizes wrinkling by tumbling the clothes. • Water evaporation requires large amounts of heat. • Don’t over dry clothes! • Dry clothes outside on clothesline whenever possible. • Vacuum lint from motor housing 3-4 times per year.
DISHWASHERS • Dishwashers use less hot water than washing dishes by hand, but requires the water to be 20 degrees F hotter. • Buy a dishwasher with an energy saving switch. • Wash only full loads during off-peak hours. • Clean filter screen regularly. • Follow maintenance instructions.
DISHWASHERS Make sure dishes are rinsed thoroughly before running load!
REFIGERATOR-FREEZERS • The larger the unit, the more energy required to maintain desired temperature. • Refrigerator should be kept between 38-42 degrees F. • Manual defrost freezers use the least amount of energy, typically 55-60% less! • Buy a model with extra improved insulation. • Buy one with a seasonal energy-saving switch. Saves 15% of annual operating costs. • Top/bottom freezers are more energy efficient than side by side models.
CENTRAL AIR CONDITIONING • Central air conditioners (central ACs) are rated according to their seasonal energy efficiency ratio (SEER). • This is the ratio of cooling output to power input for a hypothetical average U.S. climate. • The higher the SEER, the more efficient the air conditioner. SEER standards requirements were raised to 13 in 2006 (from ~6-7)
WHAT CAN YOU DO AT HOME • Look for Energy Stars labels. • Turn off the lights when you leave a room. • Buy compact fluorescent light bulbs. • Shut doors behind you so that heat does not escape. • Seal windows and doors to prevent air drafts. • Make sure your refrigerator is an energy star product because it uses the MOST electricity out of all appliances. • Use toaster oven or microwave instead of oven when possible.
WHAT ELSE CAN YOU DO? • Walk/bike for short, local trips. • Use mass transit (trains, bus, ferry) • Wear extra/less layers of clothing instead of turning up/down the thermostat. • Turn off lights when not needed.
REDUCING ENERGY WASTE IS IMPORTANT BECAUSE… • Decreases rate at which fossil fuels become economically depleted and allows extended time to phase in renewable energy resources. • Decreases dependency on foreign oil resources (probably not by drilling in ANWR) • Reduces local and global environmental damage. • Quickest and cheapest way to slow projected global warming. • Improves competitiveness in the International Marketplace.
Ways to improve energy efficiency • Power Utilities are the largest industry in USA – “regulated monopolies” – most utility companies make money by increasing the demand for electricity • Approximately 20 Utility Companies in the USA are promoting the “Negawatt Revolution” – utilities give customers cash rebates for improving energy efficiency in their houses • ONG – rebates for installing gas dryers/water heaters/heating systems • OG&E – “Smart Hours” to shift energy consumption way from 2-7pm
SAVING ENERGY IN TRANSPORTATION • Increase fuel efficiency in motor vehicles - in USA, fuel efficiency has decreased by 5% in the last 15 years • 30 hybrid/electric models available at the beginning of 2011 in US – Toyota Prius is the most well-known, has the largest market share • Problem: Little interest in consumer market because of fuel subsidies that generally promote waste and prohibit conservation interest.
GREEN BUILDINGS SAVE ENERGY • Focus is on heating, cooling and lighting • South facing – maximize angle of insolation to capture solar energy (passive solar heating). • Energy-efficient lighting (passive lighting through south-facing windows and skylights) • Superinsulation & high efficiency natural gas burners. PROBLEM: air tight buildings negatively impact indoor air quality • LEED is “nationally recognized benchmark for green building”