Hi All
I recently upgraded to an all in one washer dryer with heat pump and no longer need the dryer vent in my mechanical room. I’m considering installing a HRV and using the dryer vent as the stale air exhaust.

I dont know a lot about building science and was hoping for some help.  

My dryer vent goes straight up and out through the unconditioned attic space and out the roof. Will I have problems with condensation and freezing in the cold winter months? If so what can I do to prevent this or create drainage?

Im assuming that most of the condensation will happen at the heat exchanger when cold air meets warm air but will there be more condensation in the unconditioned part of the vent?

Thanks for your help!