- What is power consumption
- Energy efficiency and its relationship to power consumption
- What determines the power consumption
- Compressor potential
- Temperature difference
- Various functions performed
- Working in the cold
- How much do household and industrial air conditioners consume?
- Electricity consumption calculation
What is power consumption
When deciding when buying about how much power the air conditioner consumes, many users confuse different concepts. A distinction should be made between:
- power consumption, that is, the consumption of energy from the power grid;
- cooling / heating capacity (cooling and heating capacity), that is, the amount of provided cold / heat after processing of the used electrical energy.
Both of these quantities are measured in watts (watts) or kW (kilowatts). On any air conditioner and in the instructions for it there is information about how much energy it can consume, and also give it out after, but already in the form of heat or cold.
Do not confuse these designations with W / h and kW / h, since these designation units convey the amount of energy already produced per hour. For example, an air conditioner with a power consumption of 700 watts worked for one hour, while it needed 700 watt-hours or 0.7 kilowatt-hours.
Typically, the power consumption indicated by the manufacturer may differ significantly from the actual one. This is due to the fact that the rating in the manual is calculated according to the ISO 5151 measurement standard, where the temperature values are strictly fixed - with the windows and doorways closed, 27 ° C indoors and 35 ° C outside, and the operating time per day does not exceed 2 hours. When HVAC equipment operates in a domestic or industrial environment, these parameters change greatly.
Energy efficiency and its relationship to power consumption
There is such a thing as the energy efficiency of an air conditioner. What it is? This definition means the ratio of the output power for cold / heat and the power consumption, indicated in EER (cooling) / COP (heating) - the coefficient of energy efficiency. The higher the final figure is, the higher the efficiency, and the less costly in terms of electricity costs the climatic device is considered.
It should be remembered that any air conditioner consumes 3 times less energy than it gives out, since electricity consumption is used only for the circulation of freon through the refrigeration circuit and its transformation.
How efficient is the power consumption of an air conditioner can be seen on a specific example. If we assume that in moderate temperatures a household wall-mounted split system has an average electrical power consumption of about 1.2 kW, and produces a cold load of about 3.5 kW, then its energy efficiency coefficient will be closer to 3 kW. This is considered an average effective indicator.
Based on the EER and COP values, we have created energy efficiency classes, consisting of 7 divisions (A-G), as shown in the picture. The most profitable in terms of electricity costs are considered devices that correspond to class A.
What determines the power consumption
What does the power consumption of an air conditioner depend on when using? Several factors are important here:
- compressor potential;
- the difference in temperatures outside and indoors;
- function to be performed;
- cooling capacity, i.e. cold load.
Although it should be noted right away that the dependence of the consumption of the air conditioner arises only from inverters from these reasons.Models operating in the start-stop mode (temperature reached → turned off; temperature changed again → turned on), have unchanged electricity consumption values, but take more time to reach the set parameters.
The lower the compressor speed, the lower the energy consumption. Such energy-efficient air conditioners most often have an inverter way of controlling the operation of the compressor, when the energy-saving mode is automatically activated when the set temperature values are reached.
That is why the inverter is considered a more profitable purchase in comparison with conventional start-stop devices, which always work in the same power mode.
The greater the temperature difference between the room and the street, the greater the power consumption of the air conditioner in kW will be. If it is 40 ° C outside, and at home it is required to set 22 ° C, then the costs will be higher than at 25 ° C outside.
In an air conditioner with a linear energy conversion, the power consumption per hour itself will not change, but when the set temperature is reached, its compressor will turn off, and when it rises, it will turn on.
Various functions performed
Different functions require different time costs. In principle, there is an analogy here with the previous point. There will be no changes in the power consumption of the air conditioner in kW per hour, but if the time is large, the number of kW that the air conditioner "ate" will increase, therefore, the expense of funds for payment for utility bills will be higher.
Working in the cold
How does the relationship between cooling capacity and how much power is consumed by the air conditioner from the network manifest? In fact, the dependence is simple - the higher the cold load indicators, the higher the electricity consumption will be.
How much do household and industrial air conditioners consume?
The difference between how many kilowatts can be consumed by air conditioners for domestic and industrial use is very large. Household models serving an area of up to 25 m² often take less than 1 kW for the rest of the averaged indicators. Usually air conditioners installed in apartments do not exceed the consumption of 2.4 kW or 2400 W. They have a single phase connection. For semi-industrial devices (duct, column, cassette) and even more for industrial (chillers, server cabinets and the like), electricity consumption can reach hundreds of kW. They usually have a three-phase connection.
Most often, a separate power cable does not need to be connected to household refrigeration devices, but they can be plugged into a regular outlet. For the rest, it is necessary to lay a separate wire with a large cross section.
They also pay attention to which outlet is allocated for power. Old Soviet sockets may not be able to handle the load in excess of 1 kW.
Electricity consumption calculation
Before purchasing a refrigerator, many are interested in how to determine how much electricity an air conditioner consumes per hour / month or other period of time.
It is impossible to calculate 100% accurately these indicators, since it is simply unrealistic to know in advance the temperature at which the device will be used, the frequency of its switching on and many other parameters. But, starting from the consumption of the air conditioner per hour (indicated by the manufacturer), you can approximately calculate the daily consumption rate.
If we assume that the start-stop will work 6 hours a day in moderate heat in summer, and the specified demand is 800 W, then it will spend 4.8 kW per day. With an average cost per kWh of 4.32 rubles, the price of cooling in one day will be about 21 rubles. Then it is easy to roughly calculate how much electricity the air conditioner consumes per month - simply the resulting value is multiplied by the number of days per month.For example, 30 days at 21 rubles will cost you an extra 630 rubles, plus the cost of electricity.
Again, it should be borne in mind that these indicators are very conditional. In extreme heat or cold, the data can change significantly. Someone will need a round-the-clock operation of the device (top floor, a house with a flat roof, sunny side), therefore, how much electricity is consumed per month will increase 4 times, that is, 630 × 4 = 2520 rubles.
According to manufacturers, the energy consumption of an inverter air conditioner is reduced by an average of 40%. If we assume that the power values of the inverter split are the same, then under the conditions described above, the consumption will not be 0.8 kW, but approximately 0.5 kW. Here, the daily consumption will be equal to 13 rubles when working for 6 hours, and the monthly waste will be only 390 rubles. If you work 24/7, the amount will be a little more than one and a half thousand.
But all calculations here are relative, since even for several hours the air conditioner cannot function with constant potential, especially since this cannot be during round-the-clock operation. In inverter models, even the rated power consumption of the air conditioner per hour is constantly changing.
How much energy is required will become more or less clear after the first month of operation in the cold in hot weather or for heating at extremely low temperatures outside. Then the user will be able to set the required number of operating hours of the device to create a comfortable temperature and calculate the cost of payment for electricity receipts.