Seal an opening in a concrete exterior wall

[mrw]

Hello

I am going to remove a basement window (90x35 cm) to temporarily install ventilation with a simple heat exchanger.
I don’t want to brick up the hole as it needs to be reversible. The wall is about 30 cm thick.
How should I go about doing it well?

I'm considering building a module like an exterior wooden wall and then installing it in the window opening. How should I do it to make it airtight?



Thank you in advance

 

[jonaserik]

You can build frames and insert edge to edge outside and inside and some form of board that covers the hole. With insulation in between, good insulation is cellplast.