UncategorizedMarch 23, 2023by Alex

Inverter air conditioners

As it is known, according to the type of compressor, air conditioners are divided into usual (on/off models) and inverter types.


An Inverter air conditioner is a device with adjustable compressor power. After setting the desired temperature in the premises, the inverter models do not turn off but go into a mode of reduced power consumption. Due to this, they continue to maintain the microclimate at the proper level. The principle of operation of such an air conditioner is based on the inverter scheme of compressor power supply: alternating current is converted into direct current, adjusted according to certain parameters, and converted back into alternating current. This ensures continuous operation of the air conditioner with the possibility of power modulation.


Let’s look at the operation cycle of a classic air conditioner for comparison: 


– after setting the temperature on the control panel, the device begins to cool the air and at the moment of reaching the desired indicators it turns off; 


– in 15-20 minutes the temperature in a room increases by 1-2°C and the conditioner starts its work again. 


As a result of frequent temperature jumps and starts of the device, there are significant loads on the compressor operation, which leads to a reduction in service life and reliability. 


The inverter allows you to avoid the disadvantages described above, because, as already mentioned, it constantly works in the optimal mode of reduced power, instead of turning off. Besides it is much less noisy than the device of classical type, precisely maintaining the set temperature.


Choosing an inverter conditioner for your house you will get an irreplaceable assistant! It will automatically select the necessary power level for creating a comfortable atmosphere and set the temperature twice quicker as the non-inverter model. And you will also be able to save on electricity because air conditioners with inverters are extremely economical because of the increased productivity of heat exchangers and compressors, the precise microprocessor control, and a number of innovative technologies used in the creation of these devices. 


How to choose the wattage of an air conditioner?


It turns out that the power of an air conditioner should be chosen correctly, taking into consideration not only the area of the room where it will work. The important thing is also the heat inflows, coming inside the constructions from different sources – solar energy, home appliances, lighting, people, and so on. 


The power of heat flows is calculated by adding the results of calculations according to the formulas and methods presented below.


  1. P1=QxSxH, where P1 is the heat gains of the room, S and H are the area and height, and Q is the specific factor, whose value depends on the orientation of the room and is equal on average to 35 W/m.


  1. P2 – excessive heat from household appliances and office equipment in the room – 30% of the total power consumption of all the equipment or 100 W for each device. 


       3. P3 – excess heat from people in the premises: 100W per person in offices and 100-300W per person in workrooms.


  1.  P4=SvhK, where P4 – heat coming into the premises through the windows, Sî – window area, and K – heat coefficient selected from the list of standard values, depending on the sides of the world, on which the windows of the room open. 


For the northern, southern, eastern, and western directions, K is 40, 366, 309, and 350 W / sq.m. respectively, for the north-eastern, south-eastern, north-western, and south-western – 67, 403, 281, and 405 W / sq.m. respectively.


  1. P5=P1+P2+P3+P4, where P5 is the actual heat load on the room, the value of which should be considered when choosing an air conditioner. 


Here is an example of heat load calculation for a specific room with an area of 20 sq.m., ceiling height of 2.5 m, and window area facing north of 3 sq.m. There are 5 people, 2 PCs, and a printer in the room on a regular basis. Thus, according to the algorithm described above: 



P2=2×100+1×100=300 W 





So for this room, you would need an air conditioner with 2670 watts or 9130 BTU. Close to this number, the standard capacity value is 9000 BTU, which is what you should take as a basis when going to buy new appliances. 


But there is not always time for such precise calculations. For such cases, a simplified method is suitable: 


  1. In a room with a ceiling height of 2,5-3 m P1 can be calculated using the ratio of 1 kW of heat per each 10 sq.m. area. 


  1. P2 for the south, southwest, and southeast is 400 watts per square meter of window area. The same parameter for the northwest, east, and west is 300 watts/square meter of window area. The P2 value for north or northeast can be neglected.


  1. P3 is 30% of the total power consumption of the room technique. 


  1. P4 is calculated by multiplying the number of people in the room by 100 watts. 


Let’s return to our example with specific room dimensions in order to use a simplified method of calculating the capacity of an air conditioner. 


  1. P1=2 kW for a room of 20 sq.m. 
  2. P2=0, because windows are oriented to the north. 
  3. P3=300 W, as there are 3 appliances in the room, and 100 W of heat is selected for each of them. 
  4. P4=500W – 100W for each of the five people in the room. 
  5. P5=2000+0+300+500=2800 W or 9570 BTU.


As you can see, the result obtained by the simplified methodology has a slight deviation from the power value after more accurate calculations.


SDAC Heating & Air Conditioning can help you with any project, no matter whether it is the installation of a new HVAC system with efficiently routed ducts or a repair of a current system. You will always receive sound advice on any case. Our specialist at SDAC Heating & Air Conditioning will examine the ducts in your San Diego County home to make sure there are no leaks that should be addressed to avoid any malfunction in the future.


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