Helicopter air-conditioning systems are designed to regulate the cabin temperature for comfort and safety, especially in extreme climates. These systems work similarly to those in cars or buildings, using a refrigeration cycle that involves a compressor, condenser, evaporator, and refrigerant. Here's a brief overview:

1. Compressor: The refrigerant gas is compressed, increasing its temperature and pressure.
2. Condenser: The hot, pressurized refrigerant passes through the condenser, where it releases heat and condenses into a high-pressure liquid.
3. Expansion Valve: The high-pressure liquid refrigerant flows through an expansion valve, reducing its pressure and causing it to cool down rapidly.
4. Evaporator: The cooled refrigerant absorbs heat from the cabin air as it passes through the evaporator, cooling the air before it's blown back into the cabin.
5. Blower Fans: Fans circulate the cooled air throughout the helicopter cabin, maintaining a comfortable temperature.

These systems are compact and lightweight to suit the helicopter's limited space and weight constraints, ensuring effective cooling without compromising performance. After a flight in the summer it is normal to see a small puddle of water below the helicopter as the condensation from the air-conditioning system drains out. This occurs because the evaporator cools the warm, humid air inside the helicopter cabin. As the air cools, moisture condenses out of it, forming water droplets on the evaporator coils. These droplets are then collected and drained out of the helicopter through a drain line, leading to the small puddle of water you see beneath the helicopter after a flight, especially in warm and humid conditions. This is a normal and expected result of the air-conditioning process.