Thermal control devices adapted to provide improved control and efficiency in temperature cycling are provided herein. Such thermal control device can include a thermoelectric cooler controlled in coordination with another thermal manipulation device to control an opposing face of the thermoelectric cooler and/or a microenvironment. Some such thermal control devices include a first and second thermoelectric cooler separated by a thermal capacitor. The thermal control devices can be configured in a planar configuration with a means for thermally coupling with a planar reaction vessel of a sample analyzer for use in thermal cycling in a polymerase chain reaction of the fluid sample in the reaction vessel. Methods of thermal cycling using such a thermal control devices are also provided.