No abstract

Efficient use of solar energy by thermal energy storage composites and utilizing environmentally friendly cementitious materials are important trends for sustainable building composite materials. In this study, a paraffin/low density polyethylene (LDPE) composite shape-stabilized phase change material (SSPCM) was prepared and incorporated into a sulphoaluminate cement (SAC) mortar to prepare thermal energy storage mortar. The thermal and mechanical properties of SSPCM and a SAC-based thermal energy storage material (SCTESM) were investigated. The result of differential scanning calorimeter (DSC) analysis indicates that the latent heat of SCTESM is as high as 99.99 J/g. Thermogravimetric analysis demonstrates that the SCTESM does not show significant decomposition below 145 °C. The volume stability test shows the volume shrinkage percentage of the SCTESM is less than that of pure SAC mortar and far less than that of ordinary Portland cement mortar. The SCTESM has high early strength so that the compressive strength at 1-, 3-, and 7-day curing age is up to that at 28-day curing age of 67.5%, 78.3%, and 86.7%, respectively. Furthermore, a mathematical prediction model of the SCTESM compressive strength was proposed. The investigation of latent heat storage characteristics and the thermoregulating performance reveals that SCTESMs have the excellent capacity of heat storage and thermoregulating.

Lhasa is located in the middle of the Tibetan plateau, north of the Himalayas, its climatic characteristics and the form of residents are representative of the Tibetan Plateau. In order to master the indoor thermal environment of rural highland in Tibet, this paper tests the indoor and outdoor thermal environment parameters of a passive solar heating house in Lhasa, and analyzes the test results. The results show that the solar radiation intensity is high and the sunshine time is long, which is suitable for the development of passive solar energy buildings, and the interior space of the rural buildings is rationally arranged based on the use function, which can effectively improve the temperature of the main rooms. The variation law of indoor air temperature and wall temperature is approximately the same, and there is a certain phase difference between the two kinds of temperature waves;The relative humidity of the indoor air fluctuates between 18% and 32%, and the relative humidity of the indoor air is small, and the indoor humidity environment should be improved. The results of this study can provide theoretical reference for indoor thermal environment improvement in this area.