严寒地区被动房顶棚辐射供暖系统传热特性模拟

Simulation of Heat Transfer Characteristics of Ceiling Radiant Heating System in Passive House in Severe Cold Region

模拟研究被动房顶棚辐射供暖系统的传热特性,评价各影响因素(管中心距、顶棚底面与埋管中心距、埋管外直径、供水温度、热水流速)对顶棚底面表面热流密度的影响程度。供水温度升高1℃,顶棚底面平均温度升高约0.6℃,顶棚底面热流密度增大约2 W/m^(2)。当供水温度为30℃时,热水流速由0.25 m/s增至0.50 m/s,顶棚底面平均温度升高1.2℃,顶棚底面热流密度增大3.9 W/m^(2)。当供水温度为30℃时,埋管外直径由16 mm增至25 mm,顶棚底面平均温度升高2.4℃,顶棚底面热流密度增大8 W/m^(2)。顶棚底面与埋管中心距对顶棚辐射供暖系统的传热特性影响比较小,工程上取50 mm可满足要求。当室内温度为20℃时,建议埋管外直径取20 mm,供水温度取30℃,热水流速取0.3 m/s。顶棚底面热流密度影响因素由强到弱的排序为供水温度、埋管外直径、热水流速、管中心距、顶棚底面与埋管中心距。

The heat transfer characteristics of the ceiling radiant heating system in the passive house are simulated and studied.The degree of influence of various influencing factors(pipe center distance,distance between ceiling bottom surface and buried pipe center,outer diameter of buried pipe,water supply temperature and hot water flow rate)on the heat flux density of the ceiling bottom surface was evaluated.When the water supply temperature increases by 1℃,the average temperature of the ceiling bottom surface increases by about 0.6℃,and the heat flux density of the ceiling bottom surface increases by about 2 W/m^(2).When the water supply temperature is 30℃,the hot water flow rate increases from 0.25 m/s to 0.50 m/s,the average temperature of the ceiling bottom surface increases by 1.2℃,and the heat flux density of the ceiling bottom surface increases by 3.9 W/m^(2).When the water supply temperature is 30℃,the outer diameter of the buried pipe increases from 16 mm to 25 mm,the average temperature of the ceiling bottom surface increases by 2.4℃,and the heat flux density of the ceiling bottom surface increases by 8 W/m^(2).The distance between the ceiling bottom surface and the buried pipe center has little influence on the heat transfer characteristics of the ceiling radiant heating system,and 50 mm can meet the requirements in the project.When the indoor temperature is 20℃,it is recommended to take the buried pipe outer diameter of 20 mm,the water supply temperature of 30℃,and the hot water flow rate of 0.3 m/s.The factors affecting the heat flux density of the ceiling bottom surface are ranked from strong to weak as follows:water supply temperature,outer diameter of buried pipe,hot water flow rate,pipe center distance and distance between ceiling bottom surface and buried pipe center.