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地板辐射采暖系统室内热环境的数值模拟与实测分析

Numerical Simulation and Experiment Analysis of Indoor Thermal Environment with Radiant Floor Heating System

【作者】 李雄志

【导师】 王汉青;

【作者基本信息】 南华大学 , 供热、供燃气、通风与空调工程, 2008, 硕士

【摘要】 随着人们生活水平的不断提高,当今建筑采暖方式的舒适性己逐渐引起人们的重视。低温地板辐射采暖由于其舒适性高、节能、卫生条件好等优点,在北方地区得到大量推广,近年来,夏热冬冷地区也有发展的趋势。目前我国夏热冬冷地区广泛采用空调方式采暖,这种以对流传热为主的采暖方式不仅能耗高,其舒适性也受到用户的广泛批评。地板辐射采暖方式有别于传统的对流采暖方式,因其是以整个地板面为加热面,地板以辐射和对流的形式释放热量,因而研究地板辐射采暖环境下人体的热舒适性,有助于人们更好的了解该系统,为工程设计提供指导。为了较全面地反映地板辐射采暖方式下室内的热环境,本文在分析了地板采暖的传热机理及人体热舒适的基本知识的基础上,采用PMV-PPD评价指标对地板采暖方式下的人体热舒适性进行评价,同时与空调采暖方式进行对比。本文利用Airpak软件,以长沙市某套装有空气源热泵地板辐射采暖系统的办公室为研究对象,以实测为边界条件,建立了地板辐射采暖和空调采暖两种数学模型。通过数值模拟的方法,分析和比较了地板辐射采暖与空调采暖方式下的室内热环境(温度场、速度场、PMV、PPD);并以实测值与模拟结果进行了验证,得出了地板采暖和空调采暖室内的热环境特性。结果表明:地板采暖方式室内温度场和速度场分布均匀,热舒适性很好,满足国际标准ISO7730的推荐PMV—PPD值;与空调采暖方式相比,地板采暖方式室内热舒适性具有明显的优势。通过实测值与模拟值对比表明:模拟结果与实测值具有较好的吻合度,验证了采用CFD模拟室内热环境的可行性。最后对该采暖办公室进行实测,实测了系统在初始运行、连续运行、间歇运行工况下室内温度、围护结构表面温度、机组供回水温度及能耗情况,得到了夏热冬冷地区空气源热泵地板辐射采暖系统的运行特性及实际采暖效果。实测表明:热泵机组预热时间长,需要约6个小时,供回水温度才达到稳定状态;相比间歇运行,系统连续运行时,室内温度比较稳定,波动较小,室内温热感较好;在达到相同热舒适性条件下,采用间歇运行方式有利于节能。

【Abstract】 With the continuous improvement of people’s living standards,the comfort of current building heating ways has gradually aroused people’s attention. Low- temperature radiant floor heating system is being widely used in the northern region of China because of its comfort, energy saving, health and other advantages. In recent years, it also has the trend of development in hot summer and cold winter areas. At present, air-conditioning is being widely used for heating in hot summer and cold winter areas. This heating method’heat transfer form is mainly convection, which is high energy consumption, and is being widely criticized by the users because of its bad comfort. Radiant floor heating method is different from the traditional convection heating method, because the entire floor surface releases heat in the form of radiation and convection as the heating surface. Thus researching on the human thermal comfort in radiant floor heating environment can help us have a better understanding of the system; and it can provide guidance for the project design. In order to understand indoor thermal environment in the radiant floor heating way more fully, this paper adopts PMV-PPD evaluation index to evaluate human heat comfort in the floor heating environment, on the basis of analyzing the floor heat transfer mechanism and the basic knowledge of thermal comfort. At the same time, air conditioning heating method is compared.This paper makes use of Airpark software, takes one suit of office in Changsha with the air-source heat pump radiant floor heating system as study object, takes measured values as boundary conditions, establishs two kinds of mathematical models of floor heating and air conditioning heating. It uses numerical simulation method, analyses and compares indoor thermal environment (temperature, velocity, PMV(Predicted Mean Vote)-PPD(Predicted Percent Dissatisfied )) of the radiant floor heating mode and air conditioning heating mode. And it compares measured values with simulation results, educes the indoor thermal environment characteristic of the floor heating mode and air conditioning heating mode. The results show that the distribution of indoor temperature field and speed field is uniform in floor heating room, of which thermal comfort is good, and it can meet international standards of ISO7730 recommend PMV-PPD value. Comparing with air-conditioning heating mode, indoor thermal comfort of the floor heating mode has obvious advantage. Comparing with Measured value and simulation results show that the simulation values are in good agreement with the measured values,and simulating indoor thermal environment by the CFD simulation is feasible.Finally some factors of thermal enviroment are measured in the heating Office. The temperature of indoor, envelope surface and water-supply and backwater of the heat pump under initial operation, continuous operation and intermittent operation condition are measured, and the operation characteristic and actual heating effects of air-source heat pump radiant floor heating system in hot summer and cold winter area are learned. Measured results indicate: The heat pump unit preheat time is long, needs approximately six hours for the temperature of water-supply and backwater of the heat pump to come to a steady state. During continuous operation, the indoor temperature is more stable with smaller fluctuation, indoor warm feeling is better compared with intermittent operation .Under the same thermal comfort conditions, intermittent operation mode is beneficial to energy conservation.

  • 【网络出版投稿人】 南华大学
  • 【网络出版年期】2010年 02期
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