A thermal control device comprising: a first thermoelectric cooler having an active face and a reference face; a second thermoelectric cooler having an active face and a reference face; a thermal interposer disposed between the first and second thermoelectric coolers such that the reference face of the first thermoelectric cooler is thermally coupled with the active face of the second thermoelectric cooler through the thermal interposer, wherein the thermal interposer is a thermal capacitor formed of a layer of a thermally conductive material having a higher thermal mass than that of the active face and reference face of each of the first and second thermoelectric coolers; a first temperature sensor adapted to sense the temperature of the active face of the first thermoelectric cooler; a second temperature sensor adapted to sense a temperature of the thermal capacitor; and a controller operatively coupled to each of the first and second thermoelectric coolers, the controller configured to operate the second thermoelectric cooler concurrent with the first thermoelectric cooler so as to increase efficiency of the first thermoelectric cooler as a temperature of the active face of the first thermoelectric cooler changes from an initial temperature to a desired target temperature, wherein the first and second temperature sensors are coupled with the controller such that operation of the first and second thermoelectric coolers is based, at least in part, on an input from the first and second temperature sensors to the controller, wherein the controller is configured to operate the first thermoelectric cooler according to a primary control loop into which the input of the first temperature sensor is provided, and to operate the second thermoelectric cooler according to a secondary control loop into which the input of the second temperature sensor is provided, wherein the primary control loop for the first thermoelectric device is faster than the secondary control loop such that the secondary control loop lags the primary control loop so as to allow more rapid switching between heating and cooling with the first thermoelectric cooler. a first thermoelectric cooler having an active face and a reference face; a second thermoelectric cooler having an active face and a reference face; a thermal interposer disposed between the first and second thermoelectric coolers such that the reference face of the first thermoelectric cooler is thermally coupled with the active face of the second thermoelectric cooler through the thermal interposer, wherein the thermal interposer is a thermal capacitor formed of a layer of a thermally conductive material having a higher thermal mass than that of the active face and reference face of each of the first and second thermoelectric coolers; a first temperature sensor adapted to sense the temperature of the active face of the first thermoelectric cooler; a second temperature sensor adapted to sense a temperature of the thermal capacitor; and a controller operatively coupled to each of the first and second thermoelectric coolers, the controller configured to operate the second thermoelectric cooler concurrent with the first thermoelectric cooler so as to increase efficiency of the first thermoelectric cooler as a temperature of the active face of the first thermoelectric cooler changes from an initial temperature to a desired target temperature, wherein the first and second temperature sensors are coupled with the controller such that operation of the first and second thermoelectric coolers is based, at least in part, on an input from the first and second temperature sensors to the controller, wherein the controller is configured to operate the first thermoelectric cooler according to a primary control loop into which the input of the first temperature sensor is provided, and to operate the second thermoelectric cooler according to a secondary control loop into which the input of the second temperature sensor is provided, wherein the primary control loop for the first thermoelectric device is faster than the secondary control loop such that the secondary control loop lags the primary control loop so as to allow more rapid switching between heating and cooling with the first thermoelectric cooler.