相变通风屋顶的供热节能优化设计研究

提出太阳能相变屋顶系统(主要由太阳能空气集热系统、相变通风屋顶组成),将两种相变材料(PCM1、PCM2,PCM1用于供冷期蓄冷,相变温度在35℃左右。PCM2用于供暖期蓄热,相变温度在18℃左右)及风道(预制在钢筋混凝土板内,供冷期利用夜间低温空气冷却屋顶与PCM1,供暖期利用太阳能空气集热器出口热空气加热屋顶与PCM2)预制在屋顶内,形成相变通风屋顶(由上至下的基本结构为保护层、防水层、找坡层、保温层、找平层、PCM1、钢筋混凝土板),实现供冷期夜间蓄冷日间吸热、供暖期日间蓄热夜间放热。针对供暖工况,采用模拟方法,结合评价指标,对相变通风屋顶中相变材料(由于供暖工况PCM1不发生相变,因此研究对象为相变材料PCM2)的相变温度、结构(即相变材料位置)、相变材料厚度进行优化选取。A型相变通风屋顶将PCM2设置在PCM1与钢筋混凝土板之间,B型相变通风屋顶将PCM2设置在钢筋混凝土板下面,C型相变通风屋顶将PCM2设置在预制风道外圈。PCM2的最佳相变温度为18~20℃,最优结构为B型相变通风屋顶,PCM2最佳厚度为30 mm。与无相变通风屋顶(将B型相变通风屋顶中的30 mm厚PCM2相变材料替换成相同厚度的水泥砂浆,保留预制风道,其他各层材料及厚度均保持不变)相比,最佳相变通风屋顶(PCM2相变温度为18~20℃、厚度为30 mm的B型相变通风屋顶)的各项评价指标均更优。

Research on Optimal Design of Heating and Energy Saving of Phase Change Ventilated Roof

A solar phase change roof system( mainly composed of a solar air heat collection system and a phase change ventilated roof) is proposed. Two phase change materials( PCM1 and PCM2,PCM1 is used for cold storage during the cooling period,and the phase change temperature is about 35 ℃,PCM2 is used for heat storage during the heating period,and the phase change temperature is about 18 ℃) and air ducts( prefabricated in reinforced concrete slabs,the roof and PCM1 are cooled by low-temperature air at night during the cooling period, and the roof and PCM2 are heated by hot air from the outlet of the solar air collector during the heating period.) are prefabricated in the roof to form a phase change ventilated roof( the basic structure from top to bottom is protective layer,waterproof layer,slope finding layer,thermal insulation layer,leveling layer,PCM1 and reinforced concrete slab) to realize the night cool storage and daytime heat absorption during cooling period and the daytime heat storage and night heat release during heating period. Aiming at the heating conditions,the simulation method is used in combination with evaluation indicators, the phase change temperature, structure( namely,phase change material position) and thickness of phase change material in the phase change ventilated roof( since PCM1 does not undergo phase change in heating conditions,the research object is phase change material PCM2) are optimized. PCM2 is arranged between PCM1 and the reinforced concrete slab in the A-type phase change ventilated roof,PCM2 is arranged under the reinforced concrete slab in the Btype phase change ventilated roof,and PCM2 is arranged in the outer ring of the prefabricated air duct in the C-type phase change ventilated roof. The optimal phase change temperature of PCM2 is 18 to 20 ℃,the optimal structure is the phase change ventilation roof of Type B,and the optimal thickness of PCM2 is 30 mm.Compared with the non-phase change ventilated roof( the 30 mm thick PCM2 phase change material in the B-type phase change ventilated roof is replaced with the cement mortar of the same thickness,the prefabricated air duct is retained,and the materials and thickness of other layers remain unchanged),the best phase change ventilated roof( the phase change temperature of PCM2 is 18 to 20 ℃,and the thickness of B-type phase change ventilated roof is 30 mm) has better evaluation indexes.