DIY simple cheap easy HRV=fresh air system for your home (prototype 2)

I have long wanted to do something about the air quality in the bed roome so it would be nicer to sleep in there. Then I got an idea to make this heat exchanger HRV. It replaces the air very efficiently heat exchange is not overly good but it is a cheap DIY project that works. Part 2 Fan spec: ARCTIC SILENT F12 Silent Extra Quiet Case Fan 120 mm 800 RPM Airflow 37CFM/