An electronic device comprising: a circuit board that includes a first active component; a number of guide walls (10A-E), wherein, when the electronic device is installed in a chassis that includes a number of fans and when the fans operate, air flows along an airflow path that flows from an air inlet channel defined by the guide walls (10A-E) to an exhaust of the chassis, the first active component being located in the airflow path downstream of the air inlet channel and upstream of the exhaust; a thermoelectric cooler, TEC,, wherein a heat absorbing portion of the TEC extends into the airflow path upstream of the first component and a heat releasing portion of the TEC extends into the airflow path downstream of the first component, wherein the electronic device, when installed in the chassis, is connected to a rear side of a midplane of the chassis and wherein, when the fans operate, air flowing along the airflow path: flows rearward from a front side of the midplane through the air inlet channel, then flows forward on a first side of the circuit board from an opening in the air inlet channel toward the midplane, where the first active component is disposed on the first side of the circuit board, then flows upward or downward through a gap between the midplane and the circuit board, and then flows rearward on a second side of the circuit board toward the exhaust of the chassis. a circuit board that includes a first active component; a number of guide walls (10A-E), wherein, when the electronic device is installed in a chassis that includes a number of fans and when the fans operate, air flows along an airflow path that flows from an air inlet channel defined by the guide walls (10A-E) to an exhaust of the chassis, the first active component being located in the airflow path downstream of the air inlet channel and upstream of the exhaust; a thermoelectric cooler, TEC,, wherein a heat absorbing portion of the TEC extends into the airflow path upstream of the first component and a heat releasing portion of the TEC extends into the airflow path downstream of the first component, wherein the electronic device, when installed in the chassis, is connected to a rear side of a midplane of the chassis and wherein, when the fans operate, air flowing along the airflow path: flows rearward from a front side of the midplane through the air inlet channel, then flows forward on a first side of the circuit board from an opening in the air inlet channel toward the midplane, where the first active component is disposed on the first side of the circuit board, then flows upward or downward through a gap between the midplane and the circuit board, and then flows rearward on a second side of the circuit board toward the exhaust of the chassis. flows rearward from a front side of the midplane through the air inlet channel, then flows forward on a first side of the circuit board from an opening in the air inlet channel toward the midplane, where the first active component is disposed on the first side of the circuit board, then flows upward or downward through a gap between the midplane and the circuit board, and then flows rearward on a second side of the circuit board toward the exhaust of the chassis.