Determination of a System’s Entropy Using Pyroelectric Sensors

We propose a system for measuring entropy 1 variations, S, in thermal systems using pyroelectric sensors. 2 These sensors convert time-dependent temperature variations 3 into electrical current. Consequently, heat and temperature 4 variations are obtained, and sensor entropy is inferred. Various 5 polyvinylidene fluoride and lead zirconate titanate sensors have 6 been tested. Two types of measurements are performed. One in 7 the volume, to measure entropy variations in a heat source, and 8 the other on the surface, to measure entropy flux delivered by the 9 heat source. Thermodynamic models and heat transfer dynamic 10 simulations agree with the experimental results and relate the 11 sensor entropy to the heat source entropy. These results show that 12 pyroelectric sensors can enable entropy monitoring of thermal 13 processes to improve system performance. 14