Abstract: A heat exchanging element adapted to a fuel cell system includes a plurality of heat exchanging units and a fixing unit. The heat exchanging units are arranged to be spaced apart from one another along a first direction. The fixing unit fixes the heat exchanging units. Each of the heat exchanging units is demarcated into a first part and a second part extending from the first part by the fixing unit. A thermal conductivity coefficient of each of the heat exchanging units is higher than that of the fixing unit. The fixing unit is configured to slow heat conduction between the heat exchanging units. The heat exchanging element improves a heat recovery efficiency of the fuel cell system. In addition, two kinds of fuel cell systems using the above-mentioned heat exchanging element are provided.

Abstract: A projector includes a housing, an optical engine module, a light source, a system fan and a lamp cooling fan. The housing includes a air vent and an intake. The optical engine module is disposed in the housing. The light source is disposed on one end of the optical engine module for providing light. The light source includes a first side and a opposite second side opposite to the first side. The system fan is disposed adjacent to the first side for generating an airflow flowing from the first side toward the light source. The lamp cooling fan is disposed adjacent to the second side for generating an airflow flowing from the second side toward inside of the light source and the first side. The airflow generated by the lamp cooling fan mixes with the airflow generated by the system fan and then is exhausted through the air vent.