光催化氧化技术在Trombe墙采暖模式中的应用

Application of Photocatalytic Degradation in the Heating Mode of Trombe Wall

为减少室内空气处理的能耗同时改善传统型Trombe墙体功能单一的问题,将光催化氧化技术与Trombe墙采暖技术结合,提出了一种零能耗光催化空气净化型Trombe墙系统。该系统中涂覆在玻璃盖板内侧的TiO_2涂层吸收太阳辐照中的紫外波段光催化降解室内甲醛,余下的可见及红外波段被Trombe墙的吸热背板吸收用以采暖,实现了对太阳能光谱的梯级利用。将无机粘结剂与光催化剂混合涂覆在玻璃盖板内侧制得光催化玻璃,设计并于安徽省合肥市搭建了空气净化型Trombe墙及传统型Trombe墙模块的对比实验平台,利用对比实验研究了空气净化型Trombe墙的甲醛降解及采暖性能。实验结果表明,光催化型Trombe墙系统的空气瞬时集热效率为0.2～0.4,平均集热效率为0.267,与传统型Trombe墙相比,平均集热效率下降0.2;光催化型Trombe墙系统的甲醛单通性降解效率为0.2～0.4,日产生洁净空气量达112 m^3/(m^2·d)。

Trombe wall system is popularized as one kind of energy - saving systems which can provide heating-cooling or ventilation. Solar photocatalytic degradation is a potential technology to purify indoor air due to its＇ stability and friendly cost. In this study, to reduce energy consumption of indoor air treatment and improve current status of single -function in the traditional Trombe wall, a novel zero - energy air purification Trombe sample wall was proposed. The new Trombe wall combined photocatalytic degradation technology with traditional Trombe wall, and could realize indoor air purification and space heating simultaneously without auxiliary energy except solar energy. In the system, commercial photocatalyst TiO： P25 was coated on the inside borosilicate glass cover plate by a certain amount of inorganic binder Na：SiO3 .9H：O. The photocatalytic glass cover plate utilized ultraviolet radiation in the solar radiation to degrade indoor air contaminant taken typical indoor air pollution formaldehyde as example. In addition, the remaining visible and infrared bands were absorbed by absorber plate for indoor air heating. The whole process achieved cascade utilization of solar spectrum. To obtain appropriate mass ratio of photocatalyst and binder, single - pass experiment was conducted. The mass of coated photocatalyst was 2. 2 g, and the transmittance of photocatalytic glass cover plate was also tested and calculated. A full - day experiment was conducted to investigate photocatalytic degradation performance and air heating performance of photocatalytic air purification Trombe wall by comparative methods in Hefei, Anhui. In our experiments＇, the transmittance of photocatalytic glass cover plate was 77. 8%, and the UV transmittance was only 5%, which illustrated almost all the UV radiation was absorbed to motivate photocatalyst. In terms of air heating, the instantaneous thermal efficiency of photocatalytic air purification Trombe wall was in the range of O. 2 -O. 4, and the average thermal efficiency of photocatalytic air purification was O. 267. The average thermal efficiency of photocatalytic Trombe wall was O. 2 lower than that of traditional Trombe wall. And the lower thermal efficiency was the result of lower transmittance of photocatalytic glass cover plate which decreased the absorbed solar radiation of absorber plate. However, the system still had good heating effect, and the temperature rise reached 15 - 20 -C when inlet temperature was 20 -C. In addition, photocatalytic results＇ showed that traditional Trombe wall had no air purification effect while photocatalytic Trombe wall could degrade formaldehyde, and the photocatalytic degradation rate was from 0.2 - 0.4. The change of intensity of UV radiation had little effect on photocatalytic degradation rate. The fact made photocatalytic Trombe wall system have better indoor air purification performance than that of thermal catalytic Trombe under low solar radiation conditions like cloudy weather. Furthermore, the daily generated volume of clean air of photocatalytic Trombe wall reached 112m^3/（m^2·day）.