Method for transient heat flux determination in human body surface using a direct calorimetry sensor

Advantages of in vivo measurement of human skin thermal conductance using a calorimetric sensor

“…To determine the heat dissipation, an error minimization method is used (MatLab fminsearch function [15]). In the calculation, we consider that the heat dissipation is defined by a power function (W) that takes into account the stationary power values for each temperature of the thermostat and the transient caused by the instantaneous contact between the sensor and the skin [13]. The calculation method determines the parameters of the power function (W) that provide the minimum error in the reconstruction of the calorimetric signal [12,13].…”

“…The cooling system is based on a Peltier element, a heatsink, and a fan. Calibration and operation of the sensor are detailed in previous work [12,13]. Figure 1 shows the calorimetric sensor applied on the thigh and the temple.…”

“…The acquisition and control program is written in Microsoft Visual C + + and the sampling period is 0.5 s. In steady state, the oscillation of the signal provided by the measuring thermopile is ± 0.2 mV, the oscillation of the thermostat temperature is ± 5 mK, and the oscillation of the thermostat power is ± 5 mW. Thus, the uncertainty of the power measured by the sensor is ± 5 mW [12][13][14].…”

A Method to Determine Human Skin Heat Capacity Using a Non-Invasive Calorimetric Sensor

“…We assume that this increase in temperature Δ T 0 also affects the temperature of the cold focus, since T cold = T room + Δ T Peltier , where Δ T Peltier is the decrease in temperature produced by the cooling system. The value of Δ T Peltier depends on the supply voltage ( V Peltier ) of the thermopile and comes from Equation (3), whose parameters are determined experimentally [ 19 , 21 ]. …”

“…The second one, with smaller size, has a faster response and is easier to handle. With this second sensor, measurements have been performed on different subjects and its efficacy has been verified for measurements made with constant temperature of the sensor thermostat [ 21 , 22 ]. It has been experimentally found that for different constant thermostat temperatures, the heat flux decreases linearly as the thermostat temperature increases.…”