Internal Heat EXCHANGER

The 2015 Golf has the "Internal heat exchanger" (IWT), which is also used in the Volkswagen Touareg. This is a refrigerant line that forms a "pipe-in-pipe system".

This refrigerant line has a low-pressure line inside of a high pressure line. The refrigerant flows through the outer line to the expansion valve (high pressure), and flows back from the expansion valve through the inner line towards the air conditioner compressor (low pressure).

This design transfers the heat between the high and low pressure systems, increasing efficiency and reducing fuel consumption.