The document summarizes four air conditioning systems that can enhance green technology:
1) Solar-enhanced systems that use solar thermal energy to drive double effect chillers for more efficient cooling.
2) Ice-powered air conditioners that store energy at night in ice to provide cooling during peak daytime hours using 95% less energy.
3) Systems using natural refrigerants like hydrocarbons and carbon dioxide that are more energy efficient and have lower global warming potential than fluorocarbons.
4) Inverter technology that varies compressor speed based on cooling needs, providing better temperature control while reducing power consumption up to 71% compared to non-inverter systems.