In solar central air conditioner system, the air conditioner is powered by solar energy and the grid power is used as the backup power. In the daytime, the system draw the power from solar panels as preference input; when the sun is not strong enough to satisfy the needs of the A/C, the grid power will automatically get connected as input. It's mainly used at places with high electricity rates in order to cut electricity bills. It's the 4th generation models, designed for low cost, easy installation and a fast payback, requiring no batteries, no inverter, no controller-just plug in solar panels to save 40-100% power in daytime compared with an electric A/C. https://www.royalstarhomeapplian...onditioner-for-shop.html