Abstract: A range hood includes a housing, a cover, an exhaust pipe and at least two vacuum fans. The housing has a top and bottom openings opposite to each other. The cover is disposed in the housing and adjacent to the bottom opening. The cover has an air inlet facing the bottom opening. The exhaust pipe is disposed in the housing and located between the top opening and the cover. The exhaust pipe has an air outlet adjacent to the top opening and communicates with the cover. The vacuum fans are disposed in the cover and located between the air inlet and the exhaust pipe. Each vacuum fan has an air flow inlet adjacent to the air inlet and an air flow outlet adjacent to the air outlet. An area of the air inlet is greater than or equal to an area of the air flow inlets.

Abstract: A projector includes a casing, an optical engine module, and a heat dissipation module. The optical engine module is disposed in the casing. The heat dissipation module is disposed in the casing and includes a heat dissipation fin set. The heat dissipation fin set includes at least one heat dissipation fin and at least one turbulent structure. The heat dissipation fin has a surface. The surface includes a first turbulent region and a second turbulent region. The first turbulent region is adjacent to the second turbulent region. The turbulent structure is disposed at least one of the first turbulent region and the second turbulent region, and the turbulent structure protrudes from the surface. An opening is formed between a top end of the turbulent structure and the surface.