太阳能通风结合相变墙在苏北沿海的应用研究

结合苏北沿海地区的气候特点,通过对苏北沿海代表性城市盐城地区的室外温度、太阳光线强度等外部环境展开分析,选择相变温度以及潜热较为合理的相变材料展开实验,从而了解太阳能烟囱以及相变蓄热墙在改变室内热环境和针对负荷所表现出的削峰移峰2个方面影响作用。实验结果显示,在盐城同样的室外温度环境下,采用相变墙的房间具有明显的隔热保温作用,有效提升了室内环境的舒适度。充分说明,相变房温度条件得到了改善,房间给人更高的舒适感,降低了空调负荷,达到了节约能源的目的。     

南疆传统大空间建筑的夏季热环境实测分析

为了解典型干热气候下南疆地区传统大空间建筑的夏季室内外热环境,选取喀什阿帕克霍加麻扎建筑群中的主墓室、大清真寺内殿、侧殿、外殿和室外环境作为研究对象,对其温度和相对湿度进行了实测。通过测试结果的分析发现：喀什地区夏季室外昼夜温差大,主墓室的热稳定性明显优于大清真寺内殿和外殿,围护结构材料热惰性大、开口面积小,建筑体型系数小,内部有热缓冲区是主墓室热稳定性好的主要原因;大清真寺外殿出挑深度与太阳角度关系密切;室外绿化、水体作为下垫面的降温和加湿效果优于广场。结论可为当地现代大空间建筑室内外环境的气候适应性设计提供参考。     

Double cooling coil model for non-linear HVAC system using RLF method

The purpose of heating, ventilating and air conditioning (HVAC) system is to provide and maintain a comfortable indoor temperature and humidity. The objective of this work is to model building structure, including equipments of HVAC system. The hybrid HVAC model is built with physical and empirical functions of thermal inertia quantity. Physical laws are used to build the sub-model for subsystems that have low thermal inertia while the empirical method is used to build the sub-model for subsystems with high thermal inertia. The residential load factor (RLF) is modeled by residential heat balance (RHB). RLF is required to calculate a cooling/heating load depending upon the indoor/outdoor temperature. The transparency, functionality of indoor/outdoor temperatures and simplicity of RLF makes it suitable for modeling. Furthermore, the parameters of the model can be calculated differently from room to room and are appropriate for variable air volume (VAV) factor. Nowadays, a VAV system is universally accepted as means of achieving both energy efficiency and comfortable building environment. In this research work, a pre-cooling coil is added to humidify the incoming air, which controls the humidity more efficiently inside conditioned space. The model presented here is verified with both theoretical and numerical methods.     

Measurements of indoor thermal environment and energy analysis in a large space building in typical seasons

Shanghai International Gymnastics Stadium is the selected object for site-measurement. The site-measurements have been carried out during summer, winter, and the transitional seasons. Their indoor thermal environments were controlled by continuous air-conditioning, intermittent air-conditioning and natural ventilation, respectively. The site-measurement includes outdoor environment (the weather conditions and peripheral hallway), indoor air temperature distribution (the occupant zone temperature, radial temperature near upper openings and the vertical temperature distributions, etc.), and the heat balance of air-conditioning system, etc. It is found that temperature stratification in winter with air-conditioning is most obvious. The maximum difference of vertical temperature is 15 °C in winter. The second largest one is 12 °C in summer, and less than 2 °C in the transitional season. The results of measurements indicate that it is different in the characteristics on energy saving of upper openings during the different seasons. With heat balance measurements, it is discovered that the roof load and ventilated and infiltrated load account for larger percentages in terms of cooling and heating load. In this paper, many discussions on the results of site measurements show some characteristics and regulations of indoor thermal environment in large space building.     

空调设备排热对传热、新风冷负荷的影响

建立了室内外热环境耦合计算模型。通过实地测量,验证了模型模拟结果的准确性。采用该模型,以某典型办公建筑群为研究对象,探讨了空调设备排热对传热冷负荷及新风冷负荷的影响。空调设备排热加大了传热冷负荷及新风冷负荷,对新风冷负荷的影响更为显著。     

大空间建筑室内热环境现场实测及能耗分析

通过对上海国际体操中心室内热环境夏季工况的现场实测,得到了大空间建筑的室内温度分布;通过对能耗的实测分析得到了大空间建筑的室内负荷构成。现场实测分析计算结果对大空间建筑热环境设计和空调设计具有一定的参考价值。     

The characteristics of space cooling load and indoor humidity control for residences in the subtropics

For residential buildings located in the subtropics, it is more challenging and difficult to deal with space latent cooling load than space sensible load, using a room air conditioner (RAC), partly due to hot and humid climates. This paper reports a simulation study on the characteristics of space cooling load and indoor humidity control for residences in the subtropics, using a building energy simulation program. Both the weather conditions and the typical arrangements of high-rise residential blocks in subtropical Hong Kong were used in the simulation study. The simulation results on both the space cooling load characteristics and the hourly application sensible heat ratio (SHR) in the living/dining room and the master bedroom in a selected west-facing apartment under different operating modes of RACs in the summer design day are presented. The problem of indoor humidity control due to the mismatching between an application SHR and an equipment SHR in the two rooms both in the summer design day and during part load operations and the influences of indoor furnishings acting as moisture capacitors on indoor RH level are discussed.     

A study of the effectiveness of passive climate control in naturally ventilated residential buildings in Singapore

Singapore has the hot and humid climate throughout the year. Many passive climate control methods are adopted in the naturally ventilated residential buildings to help achieve thermal comfort and reduce the energy consumption of air-conditioning. A field measurement and computational energy simulations were conducted to examine the effectiveness of commonly used passive climate control methods for these buildings. The effect of building orientation, façade construction, special roof system and window shading device on indoor thermal environment and cooling load was studied. The surface temperature of external wall and indoor thermal environment was measured to analyze the façade thermal performance. The cooling load was simulated to evaluate the effectiveness of various passive climate methods. Using the special roof system as thermal buffer is the most efficient method to reduce the room cooling load.     

商业综合体冷站用能分析与优化

商业综合体由于在内部空间结构、功能及人员行为方面的复杂性,其负荷特征、空调运行及室内环境等状况复杂,冷站设计及节能优化需要结合自身特点。首先,针对商业综合体分析其空调使用需求特征,通过室内热湿环境实测分析,发现室内环境较传统商业建筑波动较大,不同业态室内环境有显著差异。其次,通过冷站实际运行工况分析其能耗特征、供冷系统运行模式及问题,发现商业综合体冷负荷稳定、冷站运行时间长、冷机设计容量普遍存在过大的问题。最后,利用DeST软件对两类典型空间分布(环绕型、中庭型)的商业综合体建立模型,分析不同区域、不同时间段的负荷特征,并根据业态负荷或时间负荷特征对冷源设计方案进行优化设计和对比,发现按照业态负荷特征对体量大、业态布局分散且各业态负荷差异大的商业综合体进行冷源设计对冷站节能有利。     

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。     

Courtyard design impact on indoor thermal comfort and utility costs for residential households: Comparative analysis and deep-learning predictive model

A courtyard is an architectural design element which is often known as microclimate modifiers and is responsible to increase the indoor occupant comfort in traditional architecture. The aim of this study is to conduct a parametric evaluation of courtyard design variants in a residential building of different climates with a focus on indoor thermal comfort and utility costs. A brute-force approach is applied to generate a wide range of design alternatives and the simulation workflow is conducted by Grasshopper together with the environmental plugins Ladybug and Honeybee. The main study objective is the evaluation of the occupant thermal comfort in an air-conditioned residential building, energy load, and cost analysis, derived from different design variables including courtyard geometry, window-to-wall ratio, envelope materials, heating, and cooling set-point dead-bands, and building geographical location. Furthermore, a Deep Learning model is developed using the inputs and outputs of the simulation and analysis to transform the outcomes into the algorithmic and tangible environment feasible for predictive applications. The results suggest that regarding the thermal loads, costs, and indoor thermal comfort index (PMV), there are high correlations between the outdoor weather variation and dead-band ranges, while in extreme climates such as Singapore, courtyard spaces might not be efficient enough as expected. Finally, the highly accurate deep learning model is also developed, delivering superior predictive capabilities for the thermal comfort and utility costs of the courtyard designs.     

蒸发冷却在我国不同区域地下工程中的适用性分析

以送风状态点的干球温度、湿球温度及含湿量为基准,建立了蒸发冷却适用区域的6区模型,并以室内状态点的上限值作为送风状态点,分别以夏季空调室外设计参数、地下工程夏季空调设计参数、夏季空调干球温度及不满足200 h含湿量作为室外状态设计参数,计算并分析了各种形式的蒸发冷却系统在我国不同区域地下工程中的适用性,为蒸发冷却在地下工程中的应用提供基本设计依据。     

南方建筑非透明围护结构热工与节能设计

如何兼顾冬夏两季建筑供暖空调负荷和能耗,保证室内热环境质量,确定最适宜的热工特性,是长期困扰中国南方建筑围护结构热工与节能设计的难点。通过对夏热冬冷和夏热冬暖地区建筑在采暖、空调与自然通风条件下动态热过程的分析,研究了这一地区围护结构热特性与能耗的制约关系,以及对室内热环境与建筑热稳定性的作用机理。在兼顾冬季保温与夏季隔热的情况下,将建筑全年能耗作为控制目标,从室内热环境质量、节能效果、围护结构的安全性、可靠性、经济性和实用性等角度评价目前所采用的围护结构节能技术存在的问题,提出一种适宜南方气候的建筑围护结构热特性指标及构造形式。     

居住建筑室内热环境低能耗营造的多目标设计方法

人居环境改善涉及重大民生问题,节能减排是国家重大战略。因此,有必要寻求合理的居住建筑设计方法,使设计方案既满足居民的室内热舒适需求又能降低建筑能耗。基于多目标遗传优化算法,建立能够对建筑设计方案进行优化、实现增加室内热舒适时间比例的同时降低建筑全年冷热负荷的居住建筑设计双目标优化模型。最后,以重庆典型户型为实例进行优化,优化后的设计方案建筑全年冷热负荷降低了47.74%,室内热舒适时间比例提高了3.94%,验证了模型的可行性和准确性。     

Enhanced conduction-corrected modified effective temperature as the outdoor thermal environment evaluation index upon the human body

This paper aims to clarify the handling technique of the solar radiation in an element of the thermal environment evaluation indices and to add expansions and improvements to conduction-corrected modified effective temperature ETF (Kurazumi et al., 2009) that can quantify the comprehensive effect on sensational and physiological sense and the effect of individual meteorological elements on the same evaluation axis applicable to an outdoor environment. Mean radiant temperature and radiant heat transfer coefficient of the outdoor space was defined. Enhanced conduction-corrected modified effective temperature ETFe that is ETF including short-wave solar radiation in outdoor space was defined. This sensational and physiological climatic environment index can make temperature convert each effect of difference in posture; air velocity; long-wave radiation in the outdoor space; short-wave solar radiation; contact surface temperature and humidity into individual meteorological elements. The addition of each temperature-converted factor is possible and quantifying the composite effect on sensational and physiological sense in the outdoor spaces as well as the discrete effect of each meteorological element is possible on the same evaluation axis. Consequently, it is possible to make the climate modification effects due to tree shade and areas of water that improve the urban thermal environment quantitatively explicit.     

A study on the characteristics of nighttime bedroom cooling load in tropics and subtropics

In both tropical and subtropical regions, residential air conditioning serves to maintain appropriate indoor thermal environments not only at daytime, but also at nighttime in bedrooms for sleeping. However, the current practices for air conditioning are primarily concerned with the situations in which people are awake at daytime. Therefore, these may not be directly applicable to nighttime bedroom air conditioning. This paper reports on a simulation study on the characteristics of nighttime bedroom cooling load in tropics and subtropics, using a building energy simulation program. The weather conditions of and the typical arrangements of high-rise residential blocks in Hong Kong are used in the simulation study. The simulation results on the cooling load characteristics in bedrooms under three different operating modes of room air conditioners (RACs) at the summer design day, the breakdown of the total cooling load in a bedroom at nighttime operating mode (NOM), indoor air temperature and mean radiant temperature variation at NOM, and the effects of indoor design air temperature on the cooling load characteristics at NOM are presented. The differences in the cooling load characteristics among three different operating modes and the issues related to the sizing of RACs used in bedrooms are discussed.     

城市规划阶段建筑空调负荷预测方法

提出一种基于建筑空调负荷指标和气象参数的负荷因子法,分别计算建筑围护结构负荷、新风负荷、人员负荷、照明负荷及设备负荷,逐时叠加获得总的建筑空调负荷。利用正交试验对建筑空调负荷影响因素的显著性进行了分析,得出室外气象条件、室内设计参数及新风标准为建筑空调负荷预测的显著性影响因素。     

Indoor cooling/heating load analysis based on coupled simulation of convection,radiation and HVAC control

A computational fluid dynamics (CFD) simulation for analyzing indoor cooling/heating load is presented in this study. It is coupled with a radiative heat transfer simulation and heating, ventilating, and air-conditioning (HVAC) controlling system in a room. This new method feeds back the outputs of the HVAC system control to the input boundary conditions of the CFD, and this method includes a human model to evaluate the thermal environment. It would be used to analyze the heating/cooling loads of different HVAC systems under the condition of the same human thermal sensation (e.g. PMV, operative temperature, etc.) even though the temperature and air-velocity distribution in the room are different from each other.To examine the performance of the new method, a cooling load and a thermal environment within a semi-enclosed space, which opens into an atrium space, is analyzed under the steady-state conditions during the summer season. This method is able to analyze the indoor cooling load with changes of target thermal environments of a room and/or changing clothing conditions of occupants considering the temperature and air-velocity distribution in the room. In this paper, two types of HVAC system are compared; i.e. radiation-panel system and all-air cooling system. The radiation-panel cooling system is found to be more energy efficient for cooling the semi-enclosed space. Changes of the level of thermal environment reduce cooling load effectively in case of the all-air cooling system while the radiation-panel system does not reduce cooling load even though the targeted thermal condition is relaxed. Energy saving effect is expected by easing the clothing conditions of occupants. In this study, the reducing effect of cooling load is quantitatively evaluated with clothing conditions also.     

Investigation of transient thermal environments

Human beings are commonly exposed to transient thermal environments in their daily life. But most of the studies on indoor thermal environment have been conducted under steady-state conditions. The aim of this paper is to summarize the investigation on human responses to transient thermal environment carried out by the indoor environment group at Tsinghua University, and to predict the possibility of using their research findings in practice. Human responses to transients have some special characteristics, which could be beneficial to environmental control. Air movement is especially effective at realizing a transient thermal environment, offsetting higher air temperature or operative temperature in warm climates. Based on the analysis of measured data, the characteristics of air movement outdoors are different from artificial air supply such as fans or air supply outlets, in the probability distribution of their velocities, turbulence intensity, and power spectrum. Based on subjective experiments, it is evident that artificial air movement, which is mainly simulated with outdoor airflow characteristics, has the highest occupant preference in warm conditions. Experimentally simulated air movement improves not only whole-body cooling, but also local cooling as from personal air supplies. Finally, it is important that introducing simulated natural air movement into the space in warm or hot conditions could significantly decrease the building's energy consumption.     

Optimization of indoor climate conditioning with passive and active methods using GA and CFD

This study aims at the development of an optimal design tool using a genetic algorithm (GA) and computational fluid dynamics (CFD). Random variables (fluctuating outdoor conditions), passive design elements (model variables) and active design elements (HVAC system) were set up to represent a realistic building environment. A combination of designs is determined based on the relationship between fluctuating outdoor conditions and the HVAC system in the optimal design search. Building environment designs should consider both active and passive design elements because the HVAC system keeps adjusting the supply air flow rate until the indoor climate reaches target conditions when outdoor conditions are changing.