When an evaporator and heat exchanger are in the same system, which component comes before the other?

In a system where both an evaporator and a heat exchanger are present, the typical configuration is for the heat exchanger to come before the evaporator. This is because the heat exchanger serves to transfer heat from one fluid to another, thereby pre-conditioning the fluid that will later enter the evaporator.

When the heat exchanger is positioned before the evaporator, it allows for better thermal efficiency by ensuring that the refrigerant entering the evaporator is at a higher temperature, which helps in the evaporation process. The refrigerant absorbs heat from the fluid passing through the heat exchanger, which facilitates a more efficient phase change from liquid to vapor in the evaporator.

This sequence is particularly important in HVAC systems, where maintaining the right temperatures and heat transfer efficiency is crucial for optimal system performance. Inconsistent or reversed order might lead to lesser efficiency and improper operation of the refrigeration cycle.