A new method to determine thermophysical properties of PCM-concrete brick

Accurate measurement of thermophysical properties of PCM-concrete brick is very important for simulation and evaluation of its energy saving performance. However, there is currently no effective way to accurately measure thermophysical properties of PCM-concrete brick. First we analyzed the shortcomings of using traditional testing methods to measure thermophysical properties of PCM-concrete brick. We then proposed a new method based on the inverse problem, which deals with the measurements of thermal conductivity and specific heat of PCM-concrete brick during the phase change process. The equivalent specific heat distributions of 4 wt% and 6 wt% PCM-concrete brick were determined using this method. We found that the accuracy (the relative error of the calculated cp based on the inverse problem and their real values ranges from 10.43% to 19.4%) was acceptable for engineering use. The influences of the temperature segments span and optimization algorithms were analyzed. The results showed that the Sequential Quadric Programming (SQP) method provides the highest accuracy and least complexity compared with the Particle Swarm Optimization and Genetic Optimization methods. Finally, we suggested how to apply this method to other similar problems to extend its application scope.