how to work out how much energy is used?
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['Device Wattage (watts) x Hours Used Per Day = Watt-hours (Wh) per Day.', 'Device Usage (Wh) / 1000 (Wh/kWh) = Device Usage in kWh.', 'Daily Usage (kWh) x 30 (Days) = Approximate Monthly Usage (kWh/Month)']
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Calculate the kilowatt-hours (kWh) required to heat the water using the following formula: Pt = (4.2 × L × T ) ÷ 3600. Pt is the power used to heat the water, in kWh. L is the number of liters of water that is being heated and T is the difference in temperature from what you started with, listed in degrees Celsius.
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Calculate the kWh use for each appliance. The formula for kWh is watts multiplied by hours used and then divided by 1000. For instance, a 100-watt light bulb used for 10 hours would use one kWh. Add all of the kWh totals from your appliances to get an idea of your electrical load that you use every day.
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W is the power consumption in watts. For example, if the electric motor uses 50 amps at 240 volts, the wattage is 50 x 240 x 1.73, or 20,760 watts. Electricity costs are based on kilowatts (kW), so divide watts by 1000 to convert to kilowatts (20,760 wats/1000 = 20.76 kW). Record the time the motor is in operation.
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Divide the number of watts by 1000 to convert the number from watts to kilowatts. 60W divided by 1000 results in 0.06kW. Multiply the number of kilowatts by the number of hours the device will be used. If the device will be used for three hours, multiply 0.06kW by three to produce 0.18kWh.
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So, just multiply the watts times the hours used to get the watt-hours. (Then divide by 1000 to get the kilowatt-hours, which is how your utility charges you.) Example: 100-watt bulb x 2 hours ÷ 1000 = 0.2 kWh.
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Once you have your meter reading, you can calculate how much electricity you've used since your last electricity bill. To do so, first find your last month's electricity bill to see the reported reading. You'll then subtract last month's reading from your current reading.
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Calculate Watt-hours Per Day One kilowatt is equal to 1000 watts, so to calculate how many kWh a device uses, divide the watt-hours from the previous step by 1000.
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Divide the amount of heat energy provided to the substance, in joules, by the mass of the substance, in grams (g). For example, if 4,000 joules of energy were provided to 500 g of water, you would calculate 4,000/500 = 8. Divide the result of the previous calculation by the specific heat capacity of the substance.
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The formula for calculating wattage is: W (joules per second) = V (joules per coulomb) x A (coulombs per second) where W is watts, V is volts, and A is amperes of current. In practical terms, wattage is the power produced or used per second.
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Multiply watts by seconds to get joules. A 1 Watt device consumes 1 Joule of energy every 1 second. If you multiply the number of watts by the number of seconds, you'll end up with joules. To find out how much energy a 60W light bulb consumes in 120 seconds, simply multiply (60 watts) x (120 seconds) = 7200 Joules.
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To calculate the energy you will use over time, just multiply the power consumption by the hours of use. The 13W light fitting, on for 2 hours, will take 13 x 2 = 26Wh from the battery. Repeat this for all the appliances you wish to use, then add the results to establish total consumption.
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Multiply the grams by the Energy per gram to obtain the Energy. Note: The Energy per gram is the conversion factor. It should be multiplied in such a way that the energy is on top and the grams are on bottom because you want your final answer to be energy in Cal or kcal or kJ.
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['E = emissions;', 'A = activity rate;', 'EF = emission factor, and.', 'ER =overall emission reduction efficiency, %']
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['kW/ton = 12 / EER.', 'kW/ton = 12 / (COP x 3.412)', 'COP = EER / 3.412.', 'COP = 12 / (kW/ton) / 3.412.', 'EER = 12 / (kW/ton)', 'EER = COP x 3.412.']
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125 watts x 3 hours = 375 Wh/Day However, electricity on your bill is measured in kilowatt-hours (kWh), not watt-hours. One kilowatt is equal to 1000 watts, so to calculate how many kWh a device uses, divide the watt-hours from the previous step by 1000.
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You can calculate how many solar panels you need by multiplying your household's hourly energy requirement by the peak sunlight hours for your area and dividing that by a panel's wattage. Use a low-wattage (150W) and high-wattage (370W) example to establish a range (ex: 17-42 panels to generate 11,000 kWh/year).