I have a bunch of bell pepper plants with a ton of bell peppers on them. Can I move these guys into a greenhouse and keep them alive? Or do bell pepper plants die each year?
You can pot them and keep them alive all winter. Pepper plants are actually tropical and will last for several years.
However they have been bred to produce fruit heavy in the first year so they cannot be kept bearing forever.
Place them in a green house. They love heat and humidity. Should be misted daily and don't let them get chilled. Well drained soil. Under 50F degrees they will stop blooming and putting on new fruits. If you use a deep tray under the pots the overflow will humidfythe air without drowning the roots. Peppers do not like their roots soggy.
The smaller "hot" pepper plants are often sold as "Houseplants" because of their various colors, red thru yellow thru purple. Those are easy if kept in a sunny kitchen window. Clear them of all fruits once in a while and they will bloom again for a new crop.
Edit note; When you transplant, pick all the bigger fruits to prevent shock. I just cut mine up and put in sandwich bags for the freezer.