地板辐射供冷系统分析

本文介绍了地板辐射供冷系统的室内外设计参数选取和负荷计算方法,通过采用CFD数值模拟的方法,分析了辐射供冷地板系统在不同的室内设计温湿度及冷水温度条件下的供冷量,冷损失量及表面温度等。应用该方法可以建立系统设计查找表格为地板辐射供冷系统设计提供基础数据。本文也给出了埋管辐射地板的系统布置方式及设计流程等。     

地板辐射采暖双向散热系统夏季供冷分析

提出了地板辐射采暖双向散热系统加独立新风的设计模型,不仅可以用于冬季供热,还可以用于夏季空调.采用双向供冷空调系统后,地板表面温度与室内空调设计温度差值不大,房间舒适性高,空调系统连续运行时,无结露危险.同时,计算了采用风机盘管空调系统、地板辐射供冷加新风空调系统及双向供冷加新风空调系统在室内设计温度为24℃～28℃时的地板表面温度值,并对其进行了分析.     

基于Fluent的埋管式辐射地板传热及供冷能力研究

充分了解辐射供冷系统的传热特性有助于该系统的设计、推广及应用。构建了埋管式辐射地板的三维稳态传热模型,进行供冷工况下地板内部传热情况的数值模拟,得到了辐射地板内部及表面的温度场。经实验验证,建立的传热模型与实际误差小于9.01%。模拟分析了换热盘管长度与供水温度对辐射地板的供回水温差、供冷能力及温度分布的影响。结果表明：在相同供水温度下,换热盘管越长,埋管式辐射地板的供冷能力越弱,温度分布均匀性越差,管长每增加10 m,单位面积辐射地板供冷量约降低1.5 W/m²;在相同换热盘管长度下,供水温度越高,地板的供冷能力越弱,温度分布均匀性越好。     

地板辐射供冷系统地面温度的确定

在分析地板辐射供冷系统地面温度传热规律的基础上,建立了地板辐射供冷系统的二维稳态传热数学模型;进而利用有限单元法数值计算了地板供冷系统的地面温度,根据地面温度随供回水平均温度和室内温度的变化规律,给出了地板供冷系统适宜的供回水平均温度,最后提出了地板辐射供冷系统防止地板结露的措施,这对于地板辐射供冷系统优化系统设计,推广应用提供参考依据。     

浅析太原市地板辐射供冷的应用

通过对太原市夏季室内空气温度和相对湿度的调查,结合地板辐射供冷系统的节能、舒适等特点,对太原市采用地板辐射供冷的可行性进行了分析,得出了地板辐射供冷用于太原市居住建筑夏季降温理论上可行的结论。     

三种方式辐射供冷室内热环境对比分析

辐射供冷是一种舒适、节能的新型空调形式。为了比较相同面积顶板、地板和墙壁三种不同辐射供冷方式与置换通风相结合系统的室内热环境情况,建立供冷系统室内数值模型并运用DTRM辐射模型进行不同供冷情况的数值模拟。对室内垂直温差、吹风感、PMV-PPD指标及能量利用效率进行分析比较,发现在统一设置参数下顶板辐射供冷系统热舒适指标最为理想,地板辐射供冷系统最差;但是地板辐射供冷系统能量效率最高。计算为合理优化各不同系统提供了一定的理论依据。     

地板辐射供冷/供暖系统经济性对比分析

介绍了地板辐射系统的特点,对比分析了不同供冷/供热末端装置的经济性,提出了一种新的供冷/供暖系统评价指标——单位耗供冷/供热系数ε。利用分析法对地板辐射供冷/供暖系统与风机盘管系统和散热器系统进行了比较,结果表明,地板辐射供冷比风机盘管供冷单位耗供冷系数提高133%,地板辐射供暖比散热器供暖单位耗供热系数提高41%。     

地板辐射供冷系统水温的确定

地板辐射供冷作为一种基于低温地板辐射供暖系统发展起来的制冷技术,近年来得到了学术界的广泛关注。文章介绍了地板辐射供冷技术的国内外研究现状,对系统的特点进行了阐述,详细介绍了地板辐射供冷系统供回水温度的确定方法,解决了低温地板辐射供冷防结露的计算问题。     

新风与地板辐射联合供冷系统的设计研究

以贵州地区某医院病房为研究对象,分析了新风与地板辐射联合供冷系统的原理及设计路线。贵州地区医院病房采用联合供冷系统可行,新风送风温度较低,送风口应采取防结露措施。     

低温地板辐射供暖供冷系统传热研究

低温地板辐射供暖供冷系统作为一种新兴的供暖供冷方式,应用越来越广泛,介绍了低温地板辐射供暖供冷系统的优缺点,详细的分析了系统的供暖供冷传热过程,解决了低温地板辐射供暖供冷系统的换热计算问题,为计算热(冷)负荷提供一定的帮助。     

Numerical simulation of radiant floor cooling system: The effects of thermal resistance of pipe and water velocity on the performance

Using the existing floor heating system, the radiant floor cooling system can be used as an alternative to the conventional all-air cooling systems. In this paper, a numerical model for the radiant floor cooling system is built using finite volume method. The objective of this study is to research the effects of the thermal resistance of pipe and water velocity on the performance of the radiant floor cooling system. In order to provide better heat transfer simulation in the pipe, composite grids are used in the model. The numerical floor surface temperature and the heat flux are in agreement with the measured results. The results illustrate that the pipe has effect on the performance of the radiant floor cooling system when the thermal conductivity of the pipe is low. However, the effect of the water velocity on the performance of the cooling system is not great. The model is helpful to calculate and design such kind of radiant floor cooling systems.     

地板辐射与置换通风组合空调系统的模拟

探讨了地板辐射供暖、供冷系统与置换通风系统的组合空调系统的流程,对组合空调系统进行了数值模拟。地板辐射供暖、供冷系统与置换通风系统相结合获得了良好的室内温度场和速度场,提高了空气品质,改善了室内的热舒适性。     

Application of the control methods for radiant floor cooling system in residential buildings

In applying radiant floor cooling, its control system must prevent the floor surface condensation in hot and humid weather conditions. With no additional dehumidification system, only the radiant floor cooling system prevents floor condensation. In this case, the effects of the control of the cooling system on the indoor conditions can be changed because of the thermal inertia of the systems. Also different types of control system can be composed according to the control methods, which can affect the construction cost in the design stage. Therefore, the control methods for the radiant cooling system with respect to floor surface condensation must be studied. Furthermore, because Korean people's lifestyle involves sitting on the floor, it is necessary to evaluate if a floor cooling system will influence the thermal comfort of the occupants. This study intends to clarify the control methods of the radiant floor cooling system and to analyze the control performance and applicability of each control method with regard to the floor surface condensation and comfort by computer simulations and experiments on the control methods of the radiant floor cooling system. The results of computer simulations and experiments show that water temperature control is better than water flow control with respect to temperature fluctuations in controlling room air temperature. To prevent floor surface condensation, the supply water temperature could be manipulated according to the dew point temperature in the most humid room, and in individual rooms, the water flow rate (on/off control) can be controlled. Also, the results of radiant cooling experiments show that the floor surface temperature remained above 21 °C, the temperature difference among surfaces remained below 6 °C, and the vertical air temperature difference remained below 1.9 °C, conforming well to comfort standards.     

A calculation method for the floor surface temperature in radiant floor system

In this paper, a calculation method for the floor surface temperature in radiant floor heating/cooling system is proposed, a new formula is derived to estimate the floor surface temperature. The floor is divided into two layers. The correlation for the thermal conductivity of the lower layer is developed based on the numerical model of the radiant floor system built in this paper. The results show that the floor surface temperature values from the proposed method are in agreement with the experimental and numerical values.     

Analytical solution for heat transfer in a multilayer floor of a radiant floor system

In radiant floor systems, the distribution of the floor surface temperature, which can be used to determine the mean temperature and the lowest/highest temperature of the floor surface, is an important parameter. The mean temperature of the floor surface determines cooling/heating capacity and indoor thermal comfort. The lowest surface temperature, which considers the dew point in an indoor environment, is a crucial factor in the prevention of condensation on a floor surface. The highest surface temperature is typically considered for local thermal comfort. In this paper, an analytical solution for heat transfer in a multilayer floor structure of a radiant floor system is proposed based on the analysis of the heat transfer process of a multilayer floor, equivalent thermal resistance and separation of variables method. The corresponding formulas are derived to estimate the distribution of floor surface temperature. The calculation results are validated by experiments. The calculation and experimental results show good accordance. The absolute error between the calculation and experimental results for floor surface temperature is within 0.3°C. A method for the calculation of the dimensionless temperature of the floor surface, which can be used for radiant heating and cooling systems, is provided. Using this proposed method, the distribution of floor surface temperature and the influence of floor structure parameters on the thermal performance of floors can be estimated and analyzed.     

地板辐射与置换通风空调系统运行参数

建立了基于EnergyPlus的地板辐射供冷加置换通风空调系统模型,模拟得到的室内温度和辐射地板所承担冷量与实验结果的误差小于±7%。在此模型基础上,改变送风参数和供水参数,得到置换通风供冷量、辐射地板供冷量、地板表面温度、室内空气平均温度、AUST温度等参数的变化规律。结合热舒适性模型,得到满足室内热舒适性(-0.5≤PMV≤0.5)条件下,置换通风的送风参数和辐射地板的供水参数范围,为复合系统设计和应用提供依据。     

2006年全国暖通空调制冷学术年会综述

概要介绍了年会盛况,报道了各专题讨论会的主题,以附录介绍了低温地板辐射供暖技术,供热节能技术,安全、健康、节能的通风技术,暖通空调能源的合理利用,建筑节能——标准、设计与实践,温湿度独立控制空调系统,水系统变流量,蓄冷空调,区域供冷,地源热泵技术,地源热泵技术与工程应用,能耗模拟与系统控制,建筑环境仿真等13个专题讨论会的交流小结摘要。     

太阳辐射照度对供暖热过程影响研究

模拟了低温地板辐射供暖与对流散热器供暖系统在不同太阳辐射照度下的动态热过程.对比了室内温度及供暖耗热量等指标,结果表明在高太阳辐射照度地区地板辐射供暖系统室内过热现象更明显,地板辐射供暖能耗与散热器供暖能耗比值随太阳辐射照度的增大而增加,因此选择高太阳辐射照度地区的供暖形式时应优先采用热响应较快的散热器供暖形式.     

太阳能地板辐射供暖制冷系统模型仿真

近年来,我国北方地区新建住宅的采暖系统多数采用地板辐射供暖技术,而制冷系统仍采用传统的空调制冷技术,有必要对地板辐射制冷技术的应用进行研究,为此,针对一套实验用太阳房,搭建了太阳能地板辐射供暖制冷系统.通过计算确定了集热器面积、蓄热水箱体积、吸收式制冷机组的制冷量.利用TRNSYS仿真平台建立了系统仿真模型,并对控制策略进行了验证.仿真结果表明,该系统能有效地利用太阳能保持冬季室温18℃左右、夏季26℃左右的舒适温度.