You can make kefir in the fridge too. I do it and it takes a lot longer and tends to be less "fizzy". I also sometimes make the kefir and then strain it and store it in the fridge, I leave the grains, unrinsed, in the jar in the fridge til I next make it. This is sometimes a few days and it seems not to damage it. I've had the same grains for about 4 months now.
As to the whey, I just stir it back into the kefir and drink the whole thing.
Hope this helps