Final answer:
Condensation on the suction line occurs when the suction line temperature drops to or below the dew point temperature, the point at which air can no longer hold all of its water vapor, which then condenses into liquid.
Step-by-step explanation:
Condensation will occur on the suction line when the suction line temperature drops to a level at or below the dew point temperature. This is because the dew point is the temperature at which the air is saturated with moisture and any further cooling results in water vapor condensing into liquid form. When the temperature in the suction line reaches this critical point, the latent heat of vaporization is released, stabilizing the temperature and preventing it further drops without the removal of heat.
Low humidity conditions, such as in deserts, result in low dew points. Therefore, in these regions, condensation is less likely to occur because the air can cool down much more before reaching the dew point. However, in humid climates, the dew point is often higher, meaning that condensation can occur at higher temperatures, which has a stabilizing effect on the air temperature.