顶板辐射系统的换热性能研究

发布时间：2018-07-27 20:06

【摘要】：随着空调的普及,人们对空调的性能要求越来越高,顶板辐射空调系统节能、环保、舒适,得到人们广泛的关注。因为辐射顶板的传热过程比较复杂,对该方面的研究还不完善,本文通过实验研究与理论分析相结合的方法研究了混凝土顶板辐射系统的换热性能。首先,本文介绍了顶板辐射空调系统的原理、优缺点及系统的构成,主要介绍了系统的三种末端形式的结构和特点,并且分析了混凝土辐射顶板的传热机理。其次,搭建了顶板辐射的实验平台,通过改变埋管间距与供水温度进行了顶板辐射系统的制热工况的实验研究,获得了各组实验下的室内空气温湿度、顶板表面温度、地板温度及墙体温度等数据,根据实验数据分析了参数变化对顶板换热性能的影响,并且通过分析围护结构表面温度、室内温度梯度、顶板表面辐射换热量、平均辐射温度及作用温度随时间的变化规律来研究系统的热响应特性及蓄热性能。最后,本文以傅立叶定律为基础,提出了顶板表面换热量的当量热阻法,提出导热形状因子的概念,将顶板填充层及以下结构镜像并简化得出了填充层当量热阻的计算公式,推导出当量热阻法计算顶板供热量的计算方法,并且通过实例计算分析验证了当量热阻法的正确性,使用当量热阻法对影响顶板换热性能的因素进行了分析研究,研究结果表明:顶板表面主要以辐射的方式与室内进行热交换,室内舒适性好;热水温度越高,顶板表面温度越高,顶板的供热能力越强;室内空气温度越高,顶板表面温度越高,但顶板的供热量减小;埋管间距越大,顶板表面温度越低,顶板的供热量越小,因此不宜将埋管间距取得过大;埋管深度越大,顶板表面温度越小,顶板供热量就越小,但是影响不显著;埋管管径及室外空气温度对顶板换热性能的影响不大。
[Abstract]:With the popularity of air conditioning, people have higher and higher requirements for the performance of air conditioning, roof radiation air-conditioning system energy saving, environmental protection, comfort, people have received widespread attention. Because the heat transfer process of radiation roof is complex and the research on this aspect is not perfect, the heat transfer performance of the radiation system of concrete roof is studied by means of the combination of experimental research and theoretical analysis. Firstly, this paper introduces the principle, merits and demerits of the radiant ceiling air conditioning system, introduces the structure and characteristics of the three end forms of the system, and analyzes the heat transfer mechanism of the radiant roof of concrete. Secondly, the experimental platform of roof radiation is built. By changing the distance between buried pipes and the temperature of water supply, the heating condition of the roof radiation system is studied, and the indoor air temperature and humidity, the surface temperature of the roof are obtained. According to the data of floor temperature and wall temperature, the influence of parameter change on the heat transfer performance of roof is analyzed, and the surface temperature, indoor temperature gradient, radiation heat transfer of roof surface are analyzed. The variation of average radiation temperature and action temperature with time is used to study the thermal response and heat storage performance of the system. Finally, on the basis of Fourier's law, an equivalent thermal resistance method for heat transfer on roof surface is proposed, and the concept of heat conduction shape factor is put forward. The structure image of the top filled layer and the following structure are mirrored and the formula for calculating the equivalent thermal resistance of the filling layer is obtained. The calculation method of equivalent thermal resistance method for calculating heat supply of roof is deduced, and the correctness of equivalent thermal resistance method is verified by an example. The factors affecting the heat transfer performance of roof are analyzed and studied by using equivalent thermal resistance method. The results show that the heat exchange between the roof surface and the room is mainly by radiation, and the indoor comfort is good; the higher the hot water temperature, the higher the roof surface temperature, the stronger the heating capacity of the roof, the higher the indoor air temperature, the higher the indoor air temperature. The higher the surface temperature of roof is, the smaller the heat supply of roof is; the larger the distance between pipes is, the lower the surface temperature of roof is, and the smaller the heat supply of roof is, therefore, it is not appropriate to make the distance of buried pipe too large; the deeper the pipe is, the smaller the surface temperature of roof is. The heat supply of roof is smaller, but the influence is not obvious, and the diameter of buried pipe and outdoor air temperature have little effect on the heat transfer performance of roof.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU83

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