A linear Fresnel collector design with an operation temperature of 300 degrees C or above typically requires a solar flux concentration ratio of at least 20 on the surfaces of the receiver assembly. For the commercial linear Fresnel collector design in this work, the receiver assembly includes a secondary reflector and an evacuated receiver tube. The high-concentration solar flux may impose additional operating-temperature requirements on the secondary reflector and receiver tube. Thus, a careful heat-transfer analysis is necessary to understand the operating temperature of the receiver assembly component surfaces under design and off-design conditions to guide appropriate material selections. In this work, a numerical heat-transfer analysis is performed to calculate the temperature distribution of the surfaces of the secondary reflector and receiver glass envelope for a commercial collector design. Operating conditions examined in the heat-transfer analysis include various wind speeds and solar concentration ratios. The results indicate a surface temperature higher than 100 degrees C on the secondary reflector surface, which suggests that a more advanced secondary reflector material is needed. The established heat-transfer model can be used for optimization of the other types of linear Fresnel collectors.