What is the electrical energy?
- Electrical energy is important because this form of energy can be easily converted into other forms of energy such as heat, light, mechanical and electromagnetic energy.
- Electrical energy can be defined as the energy carried by electrical charges which can be transformed to other forms of energy by use of an electrical device or appliance.
- The energy carried by electrical charges can be transformed to other forms of energy by using different electrical appliances. Table shows the transformation of energy for a few household appliances.
Power Rating and Energy Consumption of Various Electrical Appliances
- Practically all household electrical appliances that work on the heating effect of current are marked with voltage and power ratings.
- An electrical kettle which is marked 240V, 1500 W means that the electric kettle will consume 1500 J of electrical energy every 1 second if it is connected to a 240 V supply.
- The amount of electrical energy consumed in a given time can be calculated by:
- We can see that the energy consumption of any electrical appliance depends on the power rating and the usage time. The larger the power rating in the electrical appliance, the more energy is used every second. The longer the usage time, the more electrical energy is consumed.
- Table shows the power rating and operating voltage of some household electrical appliances.
- Appliances that have a heating effect such as electric ovens and electric kettles usually have a high power rating and consume more electricity.
- The National Electricity Board (Tenaga Nasional Berhad) calculates the electricity bill according to the readings of the kilowatt-hour meter as shown in Figure.
- The unit on the electricity bill for electrical energy used at home is kilowatt-hour or kWh.
1 kilowatt-hour represents the amount of energy consumed in 1 hour by an electrical appliance at the rate of 1 kilowatt.
1 kWh = 1 kW x 1 h
= 1000 W x 3600 s
= 3.6 x 106 J
People also ask
- What is Electric Current?
- What is an electric field and how is it created?
- What is the Relationship between Electric Current and Potential Difference?
- Electromotive Force, Internal Resistance & Potential Difference of a Cell/Battery
- How series and parallel circuits are different?
- Relationship between Energy Transferred, Current, Voltage and Time
How can we reduce the amount of energy we use?
Efficient Use of Electrical Energy:
- Electrical energy is the primary source of energy consumption in any home. Electrical appliances that we use at home account for a great part of our electricity bill.
- There are many simple steps to save electricity:
- Choose appliances with an energy label.
- Choose appliances with sizes and features which best suit your needs.
- Choose appliances with a timer or an automatic power-off function.
- Clean appliances regularly or after use.
- Do not set the temperature lower than your need for air conditioners and refrigerators.
- These steps can easily become a habit, which will lower your costs and benefit our environment at the same time.
- Figure shows the average energy usage of electrical appliances in homes.
- Choosing energy-efficient appliances will give significant savings on electricity bill. Therefore household appliances should always be chosen and used on the basis of their electrical operating efficiency.
- The Energy Commission (Suruhanjaya Tenaga) has established an energy labelling scheme for household appliances to assist Malaysian consumers. With the Energy Rating Label as shown in Figure, the appliance’s energy performance can be seen at a glance. This helps us to compare and purchase the more energy efficient products.
- Most of the electrical appliances manufactured today are of high efficiency. It is a good practice to buy an energy-efficient unit to replace an old one.
- For example, when buying new lighting, choose compact fluorescent lamps (CFLs) which use about 75% less energy to give the same amount of illumination and last up to eight to ten times longer than conventional incandescent bulbs.
- If all the lightings in a house use linear fluorescent and energy-efficient compact fluorescent lamps, we can save about 50% of the lighting costs on the electricity bill.
- Although fluorescent and compact fluorescent lamps are more expensive, they pay for themselves by saving energy over their lifetime. Moreover, they provide high-quality and high- efficiency lighting.
How can you save energy in your home?
The Importance of Maintenance in Ensuring the Efficiency of Electrical Appliances
- The following are examples to keep electrical appliances operating as efficiently as possible.
- For air conditioners
- Choose the air conditioner according to the room size.
- Clean the air filters regularly.
- Try not to install the air conditioner in a position subjected to direct sunlight.
- Avoid obstructing the air inlets and outlets.
- Do not set your air conditioner to the coldest temperature. Just set it to a temperature that you feel comfortable and cool.
- Use timers, if possible, to switch on and off your air conditioners.
- For refrigerators
- Do not allow frost to accumulate to more than half an inch in the freezer. This will cause the motor to run more often.
- If the door cannot be closed tightly, the door seal may need changing.
- Clean the coil behind the refrigerator regularly so that it will work more efficiently.
- For vacuum cleaners
- Use a vacuum cleaner only when a brush or damp mop would not do the job effectively.
- Empty the dust bag frequently. Your vacuum cleaner has to work much harder to do the same cleaning when the dust bag is full.
- Clean and replace the dust filter regularly.
- The more energy efficient an appliance is, the less it costs to operate. This lowers the electricity bill you have to pay. You will find that the maintenance of household appliances is important in ensuring efficiency and to save energy.