Ventless hoods are widely used in the restaurants or cafeterias which do not need that much ventilation or just need limited use of electric cooking, either grease cooking(type 1)  or vaper with grease( limited type 1) will do the job. The 3 or 4 layer filtration will remove most of the grease, moisture and odor. Some restaurants directly use ventless fryers to solve their problems in limited space.