When charging a system with a Zeotropic or Near Azeotropic blend, what must be done to avoid fractionation?

When charging a system with a Zeotropic or Near Azeotropic blend, transferring the refrigerant as a liquid is crucial to avoid fractionation. Fractionation refers to the separation of the components of the refrigerant blend, which can occur if the refrigerant is vaporized during charging. This separation happens because Zeotropic blends have varying boiling points for their components, leading to different rates of evaporation and condensation.

By charging the system with the refrigerant in liquid form, you ensure that the proportions of the components in the blend remain consistent, maintaining the refrigerant's designed performance characteristics. When the liquid refrigerant is introduced into the system, it will correctly follow the intended thermal properties and pressure-temperature relationships, thereby avoiding the adverse effects of fractionation, which can include decreased efficiency and potential system damage.

Other methods of transferring the refrigerant can risk the mixture becoming unbalanced, which is why it's essential to adhere to this best practice when dealing with Zeotropic and Near Azeotropic blends.