Is it ok to run dryer on a non heated porch in winter?

No, it is not okay to run a dryer on a non heated porch in winter. The dryer will not function properly and may cause a fire. Dryers need to be vented to the outside and have a certain amount of space around them to function properly. When it is cold outside, the dryer may not be able to vent properly and the dryer may overheat. This can cause a fire.