Summer bypass in a Irish heat recovery system

Calahonda52

Looking at some specs for whole house HR systems.

One, German made, PH approved kit, says:
"Incorporates a summer bypass to stop the introduction of warm, humid air in the summer months and increase comfort"

This may not be an issue in Ireland
However I then read, on an Irish website:
"What is a summer bypass and do I need it?
Most manufacturers offer units with and without summer bypass. The summer bypass is an efficient way of assisting the indoor comfort level. Most bypasses open 100% and can be programmed to suit individual dwellings and requirements. The warm humid air is extracted in the normal manner - it passes through the exchanger and on out to atmosphere. The difference is with the fresh air coming into the house - with the bypass activated the air coming into the house does not pass through the heat exchanger. However, it does pass through the filtration system. The result is that you get a 'cooling effect' and an overall better indoor comfort level."

My understanding of a summer bypass is that the incoming air is not heated.

Am puzzled as to how the German one stops the humid air coming in.
Thanks
Answer
Many of the Zehnder units have enthalpy exchangers which function
differently to a ¹standard¹air to air type exchanger which has a
condensate drain to eliminate excess moisture.
The enthalpy exchanger
uses the moisture to transfer to the supply air to prevent drying.
They are taken out at the end of the humid season and reinstalled at the start.
They are alternated with a normal heat exchanger for the non humid season.

Not required here in Ireland