POWER AND ENERGY IN THE HOME BY ALISSA WHITE AND RACHEL SHAH

Overview

What is power and energy in the home?

Where does it come from?

Wattages for everyday appliances

Estimating energy consumption

Energy Efficiency

Power and Energy?In the average household, many appliances require different amounts of power so that they may function properly.

This energy and power comes from a power plant, transfers to a system of power lines, power substations, and transformers.

Transformer drum

Kilowatt-Hour Meter

Wattage

For all of the household appliances used today, they all have certain wattages.

For example:

Air Conditioner- 5,000 watts

Microwave Oven- 750-1,100 watts

Hair Dryer-1,538 watts

Coffee-1,000 watts

Estimating Energy Consumption

Watts can be calculated by amps multiplied by volts

To estimate energy consumption you can multiply wattage by hours used by and divide this by 1000

(Wattage x Hours used per day) / 1000 = daily kilowatt hour (kWh) consumption

Example: Air Conditioner

(5,000 watts x 1 hour) / 1000 = 5

kWh

Example: Water Heater

(4,500 watts x 3 hour) / 1000 = 13.5

kWh

Estimating Energy Consumption

To calculate the annual consumption in kWh per year, multiply the value from the first equation by the number of days you use the appliance during the year.

What uses the most energy?

According to a 2009 study by Lawrence Berkeley National Laboratory, the seven major household energy uses are:

29%

17%14%

13%

11%4%

12%

What uses the most energy?Space Heating—29%

Space Cooling—17%

Water Heating—14%

Appliances—13%

Lighting—12%

Other (stoves, ovens, microwaves, coffee makers, dehumidifiers)—11%

Electronics (computers, monitors, DVD players, TVs)—4%

29%

17%14%

13%

11%4%

12%

Efficiency in the Home

A way to cut the costs and reduce energy consumption in your household is to make it energy efficient.

Ways to make a house more energy efficient include changing light bulbs, insulation, reducing air infiltration, purchasing more efficient water heating, and upgrading appliances.

Efficiency- LCD/LED Display or TV

Compared to a CCFL backlit screen, a LED backlit LCD is 20-30% more efficient.

Lighting

The types of light bulbs that are mostly used in households are incandescent, compact fluorescent lamps (CFLs), and light emitting diodes (LEDs).

CFLs and LEDs are more widely used nowadays because they are more efficient than incandescent bulbs.

Incandescent Light BulbsThe incandescent light bulb is a source of electric light that works by incandescence - the emission of light caused by heating the filament.

The original form of electric lighting and have been used for over 100 years.

Edison is widely considered to be the inventor although there were earlier prototypes before his.

Incandescent Light BulbsBritish physicist, Joseph Wilson Swan, received the first

patent for a complete incandescent light bulb with a carbon filament in 1879.

Swan and Edison merged their companies and together they were the first to design a bulb that was commercially viable.

They have a very low manufacturing cost and work well on either alternating current or direct current.

They are also compatible with control devices such as dimmers, timers, and photo sensors, and can be used both indoors and outdoors.

They are extremely inefficient because approximately 90% of the energy generated with these bulbs is heat instead of light.

CFLsCFLs are known primarily for their efficiency, long life, low cost, and ease of upgrading.

CFLs are lit by an electric current that is sent through a tube containing argon and a small of amount of mercury gases. This in turn generates an invisible ultraviolet light, which then stimulates a fluorescent coating on the inside of the tube, producing visible light.

CFLsCFLs consume only 20 to 33 percent of the power of an equivalent incandescent lamp and last 13 times longer.

According to the Energy Star Web site, an Energy Star qualified-CFL bulb will pay for itself in six months and save about $30 in electricity over its lifetime.

A CFL bulb uses about 75 percent less energy than a traditional light bulb.

The United States could eliminate greenhouse gas emissions equal to 800,000 cars if each household in the country replaced just one incandescent bulb with a CFL bulb

LEDsThe first LED was invented in 1962 by Nick Holonyak, Jr., who was working as a consulting scientist for General Electric at the time.

They work by the movement of electrons through a semiconductor material.

They don't contain any hazardous mercury gas like CFLs do, but LEDs cost more than CFLs.

LEDsLED lamps use one-tenth of the energy and last up to 40 times as long as incandescent bulbs.

An LED bulb lasts 2 to 4 times longer than a CFL bulb.

LEDs are the most efficient. A 16.5-watt LED bulb is equivalent to a 20-watt CFL and a 75-watt incandescent.

According to the US Department of Energy, adoption of LED lighting over standard incandescents over the next 20 years will prevent 40 new power plants from being constructed, generate more than $265 billion in energy savings, and reduce lighting electricity demand by 33 percent in 2027.

Insulation Insulation in your home is made up of fiberglass and cellulose fiber.

Insulation in the home reduces cooling costs by around 20%.

Currently, insulation in US buildings reduces the amount of carbon dioxide by 780 million tons each year.

Sources

http://tcipg.mste.illinois.edu/lessons/PowerandEnergy.pdf

http://tcipg.org/applet-peh

http://energy.gov/energysaver/articles/estimating-appliance-and-home-electronic-energy-use

http://www.naima.org/

http://www.homepower.com/articles/home-efficiency/basics/getting-started-home-efficiency

http://energyusecalculator.com/electricity_cfllightbulb.htm

Thank You!