For a take on the classic l'orange, I used to take a tablespoon of OJ concentrate. Defat the drippings as much as possible, then deglaze the pan with dry sherry or vermouth, maybe some chicken stock if the fortified wines are too strong or the concentrate too sweet. Add the spoon of orange juice concentrate and a grinding of nutmeg. Hmmm ... haven't made that in decades! Sounds good, but my kitchen has no exhaust fan, so I only do duck outside over coals in the summer!
Why do you feel you need an exhaust fan to cook duck indoors?