# Photovoltaic power generation project load power consumption estimation

**Source:**the Internet**Release on :**2018-12-26

There are some off-grid users who have not installed electric meters. They are not very clear about their own power usage. There are also some off-grid systems that are newly built. At this time, it is necessary to estimate the daily electricity consumption. For light bulbs and electric fans, The load of the hair dryer is equal to the power multiplied by the time; but the load of the air conditioner and the refrigerator is intermittent, and the load such as TV, computer, and audio is rarely in the full power state when working, and the power is calculated. It is necessary to consider it comprehensively.

For DC circuits and AC pure resistance circuits, the load power is equal to the load voltage * current, the sinusoidal AC circuit power calculation formula is P = UIcos φ (cos φ is the power factor) φ is the phase difference between voltage and current, pure resistance circuit φ = 0, according to Trigonometric function is introduced, cos0°=sin90°=1, all, this formula can be simplified to P=UI. For inductive and capacitive loads, there is a phase difference between voltage and current (the pure inductive load voltage leads the current by 90 degrees, and the pure capacitive is the current lead voltage of 90°) φ is not 0, cosφ is not equal to 1, so Cannot be calculated by P=UI.

The calculation of the power of the three-phase asynchronous motor, but also the efficiency of the motor, so the formula is: P = √ 3 × U × I × COS Φ × η, for example, calculate the three-phase motor current of 3000 watts, (power factor is 0.86, efficiency is 0.88) If so, can be substituted into the formula, 3000 = √ 3 × 380 × I × 0.86 × 0.88, I = 6.02A.

Not every customer will be very clear about the load power. The following list is the power of common household appliances for design reference.

In household appliances, there are two types of load power consumption that are difficult to calculate. One is the intermittent working electrical appliances, such as refrigerators and air conditioners, and the other is electrical appliances whose power changes at any time, such as televisions, computers with switching power supplies and the like.

The air conditioner manual is marked with output power and input power. 1P (1) air conditioner output power (we are talking about cooling capacity) up to 2500W, but the power consumption is not 2500W. The input power (that is, the power consumption) of the 1P air conditioner is 850W-1000W per hour. However, the air conditioner is not always working. When the indoor temperature of the room drops to the set temperature, the air conditioner will stop working and be in the standby state. At this time, the power consumed is very small. If one air conditioner is used, 12 square meters of room, 24 hours a day, if they are running at full load, the power consumption is 900 * 24 = 21.6 degrees, but in fact not so much, if the room is more sealed, using energy-saving inverter air conditioner, may only consume 5 per day -8 degrees of electricity.

TV, desktop computer, there is a switching power supply, like a TV set, usually not running at rated power, power is changing with screen brightness and sound, such as a nominal 100W TV, working under normal conditions, power May only be 50-80W.

For DC circuits and AC pure resistance circuits, the load power is equal to the load voltage * current, the sinusoidal AC circuit power calculation formula is P = UIcos φ (cos φ is the power factor) φ is the phase difference between voltage and current, pure resistance circuit φ = 0, according to Trigonometric function is introduced, cos0°=sin90°=1, all, this formula can be simplified to P=UI. For inductive and capacitive loads, there is a phase difference between voltage and current (the pure inductive load voltage leads the current by 90 degrees, and the pure capacitive is the current lead voltage of 90°) φ is not 0, cosφ is not equal to 1, so Cannot be calculated by P=UI.

The calculation of the power of the three-phase asynchronous motor, but also the efficiency of the motor, so the formula is: P = √ 3 × U × I × COS Φ × η, for example, calculate the three-phase motor current of 3000 watts, (power factor is 0.86, efficiency is 0.88) If so, can be substituted into the formula, 3000 = √ 3 × 380 × I × 0.86 × 0.88, I = 6.02A.

Not every customer will be very clear about the load power. The following list is the power of common household appliances for design reference.

In household appliances, there are two types of load power consumption that are difficult to calculate. One is the intermittent working electrical appliances, such as refrigerators and air conditioners, and the other is electrical appliances whose power changes at any time, such as televisions, computers with switching power supplies and the like.

The air conditioner manual is marked with output power and input power. 1P (1) air conditioner output power (we are talking about cooling capacity) up to 2500W, but the power consumption is not 2500W. The input power (that is, the power consumption) of the 1P air conditioner is 850W-1000W per hour. However, the air conditioner is not always working. When the indoor temperature of the room drops to the set temperature, the air conditioner will stop working and be in the standby state. At this time, the power consumed is very small. If one air conditioner is used, 12 square meters of room, 24 hours a day, if they are running at full load, the power consumption is 900 * 24 = 21.6 degrees, but in fact not so much, if the room is more sealed, using energy-saving inverter air conditioner, may only consume 5 per day -8 degrees of electricity.

TV, desktop computer, there is a switching power supply, like a TV set, usually not running at rated power, power is changing with screen brightness and sound, such as a nominal 100W TV, working under normal conditions, power May only be 50-80W.

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