A numerical study on summer operation performance of PCM wallboard cooling tower coupling system in hot-summer and cold-winter regions of China

The use of phase change materials in building envelopes shows promise in reducing overall building energy consumption. Researchers are focusing on designing optimal wall structures based on varying climate characteristics to enhance building energy efficiency. This study presents a novel system that couples phase change material wallboard with cooling tower. In the summer months, the system efficiently utilizes cooling water to dissipate heat stored in the phase change material during the day, thereby maximizing the utilization of the phase change material. The research includes the design and optimization of a southward prefabricated phase change material wallboard and evaluates the long-term performance of the phase change material wallboard cooling tower coupling system through a validated numerical model. The optimization findings indicate that the system achieves maximum energy savings with a cooling water flow velocity of 0.0125 m/s. Moreover, double-level control shows a substantial improvement in system performance compared to single-level control. Long-term operation results demonstrate that the phase change material wallboard cooling tower coupling system effectively reduces indoor heat gain during summer, with a cumulative indoor heat gain of −16.29 kWh/m², representing a 343.5 % reduction compared to the common wallboard. The system has the potential to significantly decrease power consumption in air-conditioning systems, particularly in regions with hot summers and cold winters.