Simulation of hybrid ground-coupled heat pump with domestic hot water heating systems using HVACSIM+

A hybrid ground-coupled heat pump (HGCHP) with domestic hot water (DHW) supply system has been proposed in this paper for space cooling/heating and DHW supply for residential buildings in hot-climate areas. A simulation model for this hybrid system is established within the HVACSIM+ environment. A sample system, applied for a small residential apartment located in Hong Kong, is hourly simulated in a typical meteorological year. The conventional GCHP system and an electric heater for DHW supply are also modeled and simulated on an hourly basis within the HVACSIM+ for comparison purpose. The results obtained from this case study show that the HGCHP system can effectively alleviate the imbalanced loads of the ground heat exchanger (GHE) and can offer almost 95% DHW demand. The energy saving for DHW heating is about 70% compared with an electric heater. This proposed scheme, i.e. the HGCHP with DHW supply, is suitable to residential buildings in hot-climate areas, such as in Hong Kong.     

Modelling the heat consumption in district heating systems using a grey-box approach

The heat consumption in a large geographical area is considered together with climate measurements on a single location in the area. The purpose is to identify a model linking the heat consumption to climate and calendar information.The process of building a model is split into a theoretical based identification of an overall model structure followed by data-based modelling, whereby the details of the model are identified. This approach is sometimes called grey-box modelling, but the specific approach used here does not require states to be specified. Overall, the paper demonstrates the power of the grey-box approach.     

地板辐射与散热器供暖系统经济性分析

对两种供暖系统进行了初投资和年运行费用比较,同时对其各自的优缺点进行了分析,在肯定了低温地板辐射供暖系统的优点后,得出了散热器供暖系统经济性优于地板辐射供暖系统的结论。     

地板辐射供暖加热管的VBA辅助设计

介绍了一个用VBA编制的程序,用于AutoCAD绘制低温热水地板辐射供暖加热管的布置图时辅助计算加热管的长度。     

A numerical modelling technique for geosynthetics validated on a cavity model test

Numerical modelling approaches can aid in designing geotechnical constructions involving geosynthetics. However, the reliability of numerical results depends on how the model is developed, the constitutive model, and the set of parameters used. By comparing the numerical results with experiment, the present work verifies a numerical modelling technique developed to model multilayered geosynthetic lining systems for landfills. The numerical modelling technique involves strain softening at interfaces and allows the axial stiffness of the geosynthetics to evolve as a function of strain. This work focuses on a two-dimensional finite-difference model, which is used to simulate three types of experimental tests: conventional uniaxial tensile tests, direct shear tests, and a large-scale test that was used to assess the overall mechanical behaviour of a reinforced geosynthetic system that spanned over a cavity. This reinforced geosynthetic system consisted of a 50 kN/m polyvinyl alcohol geogrid reinforcement embedded in a layer of sand, a geosynthetic clay liner, a high-density polyethylene geomembrane, and a non-woven needle-punched geotextile. The uniaxial tensile tests, direct shear tests, and the large-scale test were numerically modelled and the numerical results were compared with experimental results. The results of the numerical modelling technique presented very closely match the results of the three experimental tests, which indicates that the numerical model correctly predicted the measured data.     

地板辐射供暖系统热工性能实验研究

基于对采用PFLB管材、等密度双回型铺设方式的低温地板辐射供暖系统的实验研究，得到该系统散热量与流量及供水温度关系的热工特性曲线，发现随着流量的增加，散热量对管路内平均流速的变化率呈减小趋势。通过与传统柱型散热器热工特性对比及实验数据拟合，给出了供水温度为30～60℃、水系统流量为0．03～0．60m^3／h时，该系统散热量的计算公式，并验证了公式的有效性。     

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%。     

低温地板辐射供暖系统设计

介绍了管道长度的简化计算方法以及地板表面平均温度及散热量的确定,指出进行系统设计时应绘制管道布置图,管道间距及地板表面温度应在合理范围内,供热量无法满足要求时,应设置其他供暖设备。     

直接膨胀式土壤耦合热泵系统研究进展

介绍了DX-GCHP系统和SL-GCHP系统,分析了DX-GCHP系统的循环特点及设计时需要注意的问题,回顾和总结了DX-GCHP系统的发展现状和相关研究文献,展望了DX-GCHP系统的发展前景。     

土壤耦合热泵系统地下埋管换热器传热模型的研究

在总结埋管传热理论的基础上,系统地介绍了国外关于土壤耦合热泵系统地下埋管换热器传热模型的研究进展,并给出了各传热模型的形式及其理论基础。     

Strategies for flow rate balancing in radiant floor heating systems

Flow rate balancing makes it possible to provide each zone with a design flow rate and to meet the heating load in a radiant floor heating system. Even though the control device of the heating system works well, insufficient water flow rates can degrade control performance and thermal comfort. The water flow rate should be adjusted appropriately to cope with the heating load of each zone. This study analyzes the effect of flow rate balancing upon indoor climate and thermal comfort in a radiant floor heating system through field survey and computer simulations. The results indicate that an increase in the dwelling floor area coincides with a more excessive uneven distribution of flow rate. As the gross floor area of the sample houses increases, the necessity of flow rate balancing for each zone becomes more crucial. An analysis was performed for additional hydraulic problems caused by hydronic devices such as header, valve, etc., and possible strategies to maintain the optimal flow-rate inside the pipes in a radiant floor heating system were suggested. Under part-load conditions the use of a dynamic balancing valve is a more effective method to prevent a cavitation as it reduces the pressure drop across a balancing valve.

L'équilibrage du débit permet d'assurer à chaque zone un débit de conception et de satisfaire à la charge calorifique d'un système de chauffage rayonnant par le sol. Même si le dispositif de régulation du système de chauffage fonctionne bien, des débits d'eau insuffisants peuvent dégrader les performances de la régulation et le confort thermique. Le débit d'eau devrait être réglé de façon appropriée afin de faire face à la charge calorifique de chaque zone. Cette étude analyse l'effet de l'équilibrage du débit sur le climat intérieur et le confort thermique dans un système de chauffage rayonnant par le sol en recourant à une enquête de terrain et à des simulations sur ordinateur. Les résultats indiquent qu'une augmentation de la surface habitable coïncide avec une répartition inégale encore plus accentuée du débit. Plus la superficie hors ?uvre des maisons utilisées comme exemples augmente, plus la nécessité d'un équilibrage du débit de chaque zone devient cruciale. Une analyse a été réalisée concernant les problèmes hydrauliques supplémentaires occasionnés par les dispositifs hydroniques tels que collecteur, soupape, etc., et des stratégies possibles ont été suggérées pour maintenir le débit optimum à l'intérieur des tuyaux d'un système de chauffage rayonnant par le sol. Dans des conditions de charge partielle, l'utilisation d'une soupape d'équilibrage dynamique est une méthode plus efficace pour éviter une cavitation, étant donné qu'elle réduit la chute de pression intervenant dans une soupape d'équilibrage.

Mots clés: cavitation?débit?équilibrage hydronique?chauffage rayonnant par le sol?immeubles d'habitation?confort thermique?Corée     

基于BP神经网络的地板辐射供暖系统逐时负荷预测

采用BP神经网络,可利用较少的输入参数建立地板辐射供暖系统热负荷预测模型,以大连市某超低能耗建筑为实测对象,根据实测的供暖期逐时热负荷数据建立了BP神经网络热负荷预测模型,并进行了改进.结果表明,采用基于多项式拟合改进的神经网络预测模型能够精确地预测一个单元未来24 h的逐时热负荷,预测误差为5％左右.     

壁挂冷凝式燃气锅炉与热地板在户式供暖系统中的应用

指出了现有户式供暖系统的缺点，分析了冷凝式锅炉和地板供暖系统各自的优点，介绍了壁挂冷凝式燃气锅炉与热地板联合的户式供暖系统形式。     

空气源热泵与地板供暖联合运行实验研究

在夏热冬冷地区的住宅中,对该系统在初始运行、连续运行以及停机等工况下的室温变化、能耗及机组运行情况作了实验。结果表明,优化空气源热泵与地板供暖系统之间的匹配具有很大节能潜力;利用地板供暖系统的蓄能特性,采用夜间运行、白天停机的运行模式,对电网负荷可以起到削峰填谷的作用。     

PE-X管材质量及在地板供暖中的应用

交联聚乙烯PE—X管材是低温热水地板辐射供暖系统常用的管材之一。介绍了不同交联类型的PE—X管材及其生产过程质量控制问题,同时提出了PE-X管材应用在地板辐射供暖工程中应注意的问题。     

低温地板辐射采暖和地热水供热的综合利用

针对北方地区冬季采暖实际使用情况,通过陕西咸阳一房地产开发项目,论述了低温地板辐射采暖和地热水供热在住宅开发中的综合利用,指出低温地板辐射采暖系统与地热井供热综合利用可达到高效节能的效果。     

新型低温热水地板辐射供暖结构层传热数学模型

同时考虑了地板结构层向下层房间传热及地板层上表面与各个墙之间的多面辐射换热,建立了地板辐射供暖结构层传热物理及数学模型.并将模拟计算结果与实测结果进行了对比分析,验证了模型及计算方法的正确性.     

Development of a ground-coupled heat pump system simulation model using g-function approximation for a residential code-compliant tool

This study develops a ground-coupled heat pump (GCHP) simulation model for a residential code-compliant simulation tool. To achieve this, this study proposed the g-function approximation method using polynomial curve-fitting equations. In addition, the residential air-source heat pump (ASHP) simulation model (i.e., RESYS in DOE-2.1e) was modified to include a vertical ground heat exchanger module. To check validity of the new GCHP system model, this study compared the simulation results against the results from the other simulation tools. The results between the programs showed good agreement within 5.3% differences for the annual total site energy use. Using the developed GCHP simulation model, the energy savings for a code-compliant residential building in Houston and Dallas were evaluated in comparison with the ASHP system, and the resultant annual energy savings were about 10% to 15% in the total site energy use and 30% to 40% in the heating plus cooling energy use.     

Performance assessment of a ductless personalized ventilation system using a validated CFD model

The aim of this study is twofold: to validate a computational fluid dynamics (CFD) model, and then to use the validated model to evaluate the performance of a ductless personalized ventilation (DPV) system. To validate the numerical model, a series of measurements was conducted in a climate chamber equipped with a thermal manikin. Various turbulence models, settings, and options were tested; simulation results were compared to the measured data to determine the turbulence model and solver settings that achieve the best agreement between the measured and simulated values. Subsequently, the validated CFD model was then used to evaluate the thermal environment and indoor air quality in a room equipped with a DPV system combined with displacement ventilation. Results from the numerical model were then used to quantify thermal sensation and comfort using the UC Berkeley thermal comfort model.     

太阳能热泵-地板辐射供热系统实验研究

实验研究了太阳能热泵-地板辐射供热系统的性能,并与燃油、燃气锅炉集中供热系统进行了经济性分析比较。实验结果表明,热管真空管集热器的集热效率为64·4%,U形管真空管集热器的集热效率为59%,热泵机组的能效比为3·08;室内温度变化相对机组供热时间滞后3h,有利于采用间歇运行方式降低运行费用。经济性分析结果表明,在青岛地区为节能型建筑供热时,该系统的单位面积费用年值介于燃气、燃油锅炉集中供热之间。