Incorporating PCMs into building envelope for energy conservation and maintaining indoor thermal comfort has attracted growing attention worldwide. This study focused on the development of a novel form-stable PCM, which using capric-stearic acid eutectic (CA-SA) as phase change energy storage material and White Carbon Black (WCB) as matrix. Based on theoretical prediction, CA-SA (78.40/21.60 wt.%) was prepared. Then CA-SA/WCB was obtained by capsulation of CA-SA into the pores of WCB without leakage. CA-SA/WCB was characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermal gravimetric (TG), thermal constants analyzer and thermal cycling test. Results show that WCB has good performance for interacting with CA-SA via physical interaction, indicating good adsorption and compatibility. The melting temperature and latent heat of CA-SA/WCB are 20.79 degrees C and 78.74 J/g, respectively. CA-SA/WCB is stable up to 143.10 degrees C, indicating a much higher thermal stability than CA-SA. Besides, CA-SA/WCB has a thermal conductivity of 0.38 W/(m.K) and good thermal reliability up to 500 thermal cycles. All results suggest that CA-SA/WCB possesses high thermal storage density, suitable melting temperature and thermal conductivity, good chemical compatibility and thermal stability, as well as good reliability, indicating great potential in building application. (C) 2017 Elsevier B.V. All rights reserved.