Which type of refrigerant system is least prone to leaking refrigerant?

The indirect refrigerant system is least prone to leaking refrigerant primarily due to its design, which separates the refrigerant from the environment in which it's operating. In an indirect system, the refrigerant circulates within a closed loop, transferring heat to a secondary fluid, typically water or glycol. This design allows large quantities of heat to be absorbed and rejected without the refrigerant ever being exposed directly to the atmosphere.

In contrast, other systems, such as direct systems, may have refrigerant flowing directly into the air or through other less-protected components, making them more vulnerable to leaks. Closed-loop systems are designed to minimize exposure as well, but indirect systems offer an additional layer of security because they do not rely on direct contact with the air for heat exchange. Open-loop systems, which use water from a natural source as the heat transfer medium, are even more susceptible to leaks, as they introduce larger volumes of fluid that can escape.

Therefore, the design of the indirect system inherently minimizes the risk of refrigerant loss, making it the most reliable option in terms of maintaining system integrity and preventing leaks.