In this study ,we established transient performance calculation models for air- cooled and heat pipe two-stage thermoelectric cooler devices operating in confined spaces with internal heat sources. We determined the variation laws of the cooling space temperature ,temperature differencebetween thetwojunctionsofthe module ,and cooling coefficientwith time as wellas compared the effects ofthe two heatdissipation methods on the device characteristics. We analyzed the effects of the operating current ,thermocouple two-stage area ratio ,and thermocouple leg length ratio on the temperature ,elapsed time ,and cooling coefficient. Our results showed thatfor an internal heat source power of6 W ,the temperatures of the air-cooled and heatpipe coolers were 8. 28 and 7. 86 ℃ higher than that observed without a heat source. Furthermore ,the cooling temperature of the heatpipe cooler was 1. 85℃ lower than that of the air- cooled cooler ,whereasits cooling coefficientwas 12. 12% higherthan thatofthe air-cooled cooler.