The need for temperature zoning in high-performance residential buildings

The development from poorly insulated and leaky buildings to modern high-performance buildings, such as passive houses, has led to considerable improvements regarding thermal comfort. However, user evaluations of passive houses that solely employ air heating indicate that bathrooms are often perceived as too cold and bedrooms as too warm. Based on these experiences, the functional requirement of providing thermal comfort using only air heating has not been adopted in the Norwegian standard for passive houses. Instead, usually local heat sources are installed in living rooms and bathrooms to facilitate temperature zoning within the dwelling. The questions asked in this study are how well this heating and ventilation concept functions in practice from the occupants’ point of view and whether it provides thermal comfort in the various rooms. Therefore, a questionnaire was distributed to the occupants of a typical multifamily passive house project in Norway. Despite the small sample size, the findings give important insight into the residents’ perception of the thermal conditions and clearly demonstrate the limitations of the heating and ventilation solution. Based on the results, the need for further development and further studies to provide temperature zoning is outlined.     

Reduction of energy consumption using passive architecture in hot and humid climates

Energy shortages, pollution, global warming, and the impacts of urban heat islands are among the pressing issues in this century all over the world. Historically, local architecture was based on people’s experience and knowledge. It was sympathetic to the climate and environment. After a period of building design that ignored the local climate, more passive buildings, low energy buildings, and zero buildings have come into focus because of the environmental pollution caused by an excessive use of fossil fuels. The historic architectural style in Dezful includes underground shelters, 5–12 m deep, to improve the indoor climate conditions in this hot and semi humid city. This type of underground shelter, known as a Shavadoon, is regarded as one of the passive energy strategies to seek temperature comfort using the earth annual temperature stability and natural ventilation. The present study was conducted in a house owned by Mohammad Reza Ghamsari. The house was used to test the accuracy of numerical simulation of the temperature and air flow within the Shavadoon spaces. Temperature contours, streamlines, and other related findings are reported. The results show that space conditioning costs could be cut and adequate comfort could be derived using such passive heating and cooling systems.     

Analysis of thermal comfort and indoor air quality in a mechanically ventilated theatre

Theatres are the most complex of all auditorium structures environmentally. They usually have high heat loads, which are of a transient nature as audiences come and go, and from lighting which changes from scene to scene, and they generally have full or nearly full occupancy. Theatres also need to perform well acoustically, both for the spoken word and for music, and as sound amplification is less used than in other auditoria, background noise control is critically important. All these factors place constraints on the ventilation design, and if this is poor, it can lead to the deterioration of indoor air quality and thermal comfort. To analyse the level of indoor air quality and thermal comfort in a typical medium-sized mechanically ventilated theatre, and to identify where improvements could typically be made, a comprehensive post-occupancy evaluation study was carried out on a theatre in Belgrade. The evaluation, based on the results of monitoring (temperature, relative humidity, CO₂, air speed and heat flux) and modelling (CFD), as well as the assessment of comfort and health as perceived by occupants, has shown that for most of the monitored period the environmental parameters were within the standard limits of thermal comfort and IAQ. However, two important issues were identified, which should be borne in mind by theatre designers in the future. First, the calculated ventilation rates showed that the theatre was over-ventilated, which will have serious consequences for its energy consumption, and secondly, the displacement ventilation arrangement employed led to higher than expected complaints of cold discomfort, probably due to cold draughts around the occupants’ feet.     

套室内人体热舒适的研究

借助于通用流场计算软件PHOENICS，在考虑了外界气温、太阳的热辐射条件，家具以及人员等室内微气候影响的情况下，预测了两室一厅套室内气流三维流场和温度场。得到了套室内气流的速度、温度和人体热舒适指数等参数的分布，并经过评定，该套室内的热环境达到了人体的舒适性要求。模拟计算结果对套室的设计及其空调系统的配置具有重要的参考价值，并为套室内人体热舒适的进一步研究和室内空气品质问题的研究奠定了基础。     

Evaluation and comparison of thermal comfort of convective and radiant heating terminals in office buildings

Radiant heating systems are increasingly widely utilized in buildings for its energy conservation potential and enhanced thermal comfort. This paper presented an experiment to compare the thermal comfort performance of radiant heating system with convective heating system through objective measurement and subjective survey. Six physical parameters which might influence occupants' thermal satisfaction, including the Mean Radiant Temperature(MRT), humidity, air movement, A-weighted sound level,temperature fluctuation and vertical temperature difference, were measured. In addition, 97 subjects participated in the subjective survey part of this experiment, experiencing all the three environments heated by air source heat pump, radiator and floor heating.And they were asked to vote in six thermal comfort related aspects, i.e. thermal sensation, humidity, draught, local discomfort,overall thermal satisfaction and overall preferences, plus the acoustic environment, since the operation noise of heating system might lead to complains of the occupants. It was found that in continuous heating, no significant difference between radiant and convective heating system was observed in the Mean Radiant Temperature(MRT), indoor humidity and noise issue. Though radiant heating systems resulted in lower draught risk and less local discomfort complains in the feet region due to the less significant temperature fluctuations and vertical temperature gradients, radiant heating did not have significantly higher overall thermal satisfaction votes and was not significantly more preferred by occupants.     

Numerical investigation of local thermal discomfort in offices with displacement ventilation

Local thermal discomfort in offices with displacement ventilation is investigated using computational fluid dynamics. The standard κ-ϵ turbulence model is used for the prediction of indoor air flow patterns, temperature and moisture distributions, taking account of heat transfer by conduction, convection and radiation. The thermal comfort level and draught risk are predicted by incorporating Fanger's comfort equations in the airflow model. It has been found that for sedentary occupants with summer clothing common complaints of discomfort in offices ventilated with displacement systems result more often from an unsatisfactory thermal sensation level than from draught alone. It is shown that thermal discomfort in the displacement-ventilated offices can be avoided by optimizing the supply air velocity and temperature. It is also shown that optimal supply air conditions of a displacement system depend on the distance between the occupant and air diffuser.     

银川地区被动式太阳房的室温预测

被动式太阳房是一种经济有效地利用太阳能采暖的建筑,银川地区太阳能热水器已经得到了广泛的应用,但被动式太阳房的应用较少。本文对银川地区直接受益窗与集热蓄热墙的组合式太阳房的室内温度进行预测,分析其热舒适性,以便今后更近一步的研究。     

Annual characteristics of ventilation and indoor air quality in detached houses using a simulation method with Japanese daily schedule model

This paper presents the results of investigations that were made on a simulation program, which calculates the temperature, the heat loads, the ventilation rates and the indoor air quality considering the Japanese daily schedule and the dweller's behaviour toward keeping comfortable indoor climate, in order to explain the effect of ventilation systems. In the investigation, the concentrations of carbon dioxide, carbon monoxide and formaldehyde are regarded as indicators of indoor air quality. Firstly, three types of systems were designed in a house model; that is a basic passive ventilation system, a passive stack ventilation system and a mechanical ventilation system. Next, the simulation was performed using the standard weather data on three cities in Japan; and the simulation made clear the annual characteristics of ventilation and indoor air quality. The results show that in a house with a passive ventilation system, there is much risk of indoor air pollution in spring, autumn and when air conditioned, and that indoor air quality in the rooms on the first floor differs from that on the second floor. Lastly, the performance of the ventilation systems and the solution methods of realizing these ventilation systems were discussed on the basis of the results of the simulation.     

Literature survey on how different factors influence human comfort in indoor environments

The present paper shows the results of a literature survey aimed at exploring how the indoor environment in buildings affects human comfort. The survey was made to gather data that can be useful when new concepts of controlling the indoor environment are developed. The following indoor environmental conditions influencing comfort in the built environment were surveyed: thermal, visual and acoustic, as well as air quality. The literature was surveyed to determine which of these conditions were ranked by building users as being the most important determinants of comfort. The survey also examined the extent to which other factors unrelated to the indoor environment, such as individual characteristics of building occupants, building-related factors and outdoor climate including seasonal changes, influence whether the indoor environment is evaluated as comfortable or not. The results suggest that when developing systems for controlling the indoor environment, the type of building and outdoor climate, including season, should be taken into account. Providing occupants with the possibility to control the indoor environment improves thermal and visual comfort as well as satisfaction with the air quality. Thermal comfort is ranked by building occupants to be of greater importance compared with visual and acoustic comfort and good air quality. It also seems to influence to a higher degree the overall satisfaction with indoor environmental quality compared with the impact of other indoor environmental conditions.     

室内气温对绿化屋顶当量热阻的影响

绿化屋顶在节能设计中以附加当量热阻增大屋顶总热阻值,有效减少由屋顶进入室内的热量,降低室内空气温度。但根据已有的实验研究,绿化屋顶隔热特性与室内气温是耦合关系,随室内气温的变化,绿化屋顶会呈现出不同的隔热特性。用实验测试与数值模拟相结合的方法,分析在不同室内气温下绿化屋顶、参照屋顶与等效保温屋顶内表面温度与热流的变化。结果表明:室内气温会显著改变绿化屋顶的隔热性能,其当量热阻为与室内温度正相关的变量。在被动式建筑中,绿化屋顶更能充分发挥隔热功效,且具有不向室内传热的特性。     

建筑气密性对被动房室内温度的影响

简要介绍了气密性评价方式与被动房标准。从被动房的角度出发,建立了建筑模型,利用TRNSYS软件分析了在不采取供暖和制冷措施的情况下,3种不同围护结构工况下气密性的改变对室内温度影响。结果表明,在冬季,室内温度的升高趋势随气密性改善而递增;在夏季,不开窗时,气密性性能提高会提升室内温度,降低舒适度;采取夜间通风策略后,气密性对室内温度基本无影响。     

Airflow and air temperature distribution in the occupied region of an underfloor ventilation system

Measurements were carried out in an office-type experimental room ventilated by a floor return-type underfloor ventilation system to investigate the distributions of airflow velocity and air temperature. A fan-powered floor air unit (FAU) with rectangular supply and return air outlets covered by straight-profile linear bar-type air diffusers was installed to deliver the conditioned air in the experimental room. Turbulence intensity and draught rate distributions inside the room were also calculated by using the measured data. From the experimental results, it is found that undesirable high air velocities and high draught rates were created within a small region near the supply outlet of the FAU. Temperature differences between different height levels were maintained within an acceptable comfort level under the tested supply air conditions and heat loads. The results indicated that the temperature stratification could be maintained at an acceptable comfort level by designing the supply air conditions properly. A clearance zone is suggested as a design consideration for locating the FAUs and occupants to avoid undesirable draught discomfort to the occupants.     

谈被动房建筑

介绍了被动式建筑的组成,并根据国外被动房的发展经验,对我国被动房的发展情况进行了探讨,指出被动房在外墙保温、屋面保温及新风系统等方面要求较高,从而提高了人在室内的热舒适度。     

Experimental investigation into the interaction between the human body and room airflow and its effect on thermal comfort under stratum ventilation

Room occupants' comfort and health are affected by the airflow. Nevertheless, they themselves also play an important role in indoor air distribution. This study investigated the interaction between the human body and room airflow under stratum ventilation. Simplified thermal manikin was employed to effectively resemble the human body as a flow obstacle and/or free convective heat source. Unheated and heated manikins were designed to fully evaluate the impact of the manikin at various airflow rates. Additionally, subjective human tests were conducted to evaluate thermal comfort for the occupants in two rows. The findings show that the manikin formed a local blockage effect, but the supply airflow could flow over it. With the body heat from the manikin, the air jet penetrated farther compared with that for the unheated manikin. The temperature downstream of the manikin was also higher because of the convective effect. Elevating the supply airflow rate from 7 to 15 air changes per hour varied the downstream airflow pattern dramatically, from an uprising flow induced by body heat to a jet‐dominated flow. Subjective assessments indicated that stratum ventilation provided thermal comfort for the occupants in both rows. Therefore, stratum ventilation could be applied in rooms with occupants in multiple rows.     

相变储能石膏板应用于地板供暖系统的节能效果及热舒适性分析

本文针对一种电加热相变地板供暖系统,通过模拟计算分析了其稳定性和热舒适性,并通过实验进行了验证.模拟计算结果表明相变地板供暖系统储热能力好,与普通地板供暖系统相比,室内空气温度变化平缓,人体舒适度更高.相变地板利用相变材料储存廉价低谷电热能,系统的节能性和经济性较好.     

Thermal performance of a non-air-conditioned building for passive solar air-conditioning: Evaluation of roof cooling systems

A periodic heat transfer analysis has been presented to predict the dynamic thermal behaviour of a non-air-conditioned building with evaporative cooling systems over the roof. Three different cases of evaporative cooling systems, namely, open roof pond, moving water layer over the roof, and water spray over the roof, have been studied in detail to assess their effectiveness for passive space air-conditioning. The effects of air ventilation, furnishings and ground heat conduction have been incorporated in the present analysis. Numerical computations using typical data of a harsh summer day in the Delhi climate, have been made to assess the analytical results quantitatively.It was found that the maximum cooling is achieved by water spray over the roof. However, the roof pond system with stationary water is more effective in stabilizing the fluctuations of indoor temperature as well as heat flux entering through the roof. Furthermore, with the increase in the number of air changes per hour, the time variation of indoor air approaches to that of outdoor air in phase as well as in magnitude.     

南方民宅屋顶架空遮阳网对室内外热环境的影响

为了解南方民宅屋顶自发搭建的黑色遮阳网对室内外热环境的防热效果,以两个典型民宅为研究对象对其进行实测研究,一个是厦门集美兑山村民宅,另一个是厦港片区民宅为研究对象,在晴热天气测试其室内外气候参数,对比包括遮蔽房和无遮蔽房的空气温度、湿度、黑球温度、风速、顶棚表面温度、室内热舒适PMV值、屋顶地表温度、屋顶室外热舒适SET值,结果表明黑色遮阳网对室内的遮蔽房具有明显的防热效果,白天及其他大部分时间遮蔽房比无遮蔽房的空气温度、黑球温度、顶棚表面温度、室内PMV值都明显较低,并且下午随着日照减弱各个指标的降温也更快、幅度更大、显著缩短高温的持续时间;证实黑色遮阳网的防热效果对于屋顶灰空间作用不明显,却对于灰空间下方的遮蔽房间有明显作用。     

Thermal performance of insulated roof slabs in tropical climates

Reinforced concrete roof slabs can be an ideal alternative to traditional roofs considering the better cyclone resistance that can be offered due to the self weight. However, the concrete slabs do not perform satisfactorily in warm humid tropical climatic conditions and tend to act as heated bodies for the occupants in free running spaces. As a solution, a robust roof slab insulation system is proposed and its thermal performance was determined experimentally using small and large-scale models. With comfort models developed for the people acclimatized to tropical climatic conditions, it is shown that insulated roof slabs could provide acceptable indoor conditions while providing many valuable benefits such as cyclone resistance, regaining of land lost for the house and the possibility of creation of roof top gardens.     

Indoor air quality and thermal comfort studies of an under-floor air-conditioning system in the tropics

This paper reports thermal comfort and indoor air quality (IAQ) studies of an under-floor air-conditioning (UFAC) system in hot and humid climate. Thermal comfort parameters were measured at predetermined grid points within an imaginary plane to predict the airflow pattern of the supply air jet as well as to determine the occurrence of thermal stratification in the office space. Fanger’s [Thermal Comfort Analysis and Applications in Environmental Engineering, McGraw-Hill, New York, 1970] thermal comfort index was also computed to detect the occupants’ thermal sensation. Besides, the concentration levels of dust and carbon dioxide were recorded with the intention to examine the quality of the indoor air. Statistical methods were applied to derive the relationship between air velocity and the other parameters as mentioned earlier. The main findings from the study revealed reasonable level of acceptability of IAQ associated with the UFAC system. However, occupants are likely to experience localised thermal discomfort near the supply diffusers due to the existence of large temperature gradients. In addition, a stagnant zone is discovered at sedentary level, which is caused by the parabolic airflow nature of the primary air jet.     

农村被动式住宅通风换气对室内热舒适性影响模拟分析

被动式建筑具有密闭性良好、减少能量损失的优势,在我国农村地区应用具有重要的节能意义。由于围护结构密闭性较高,被动式农村住宅通风换气技术对提高和保障室内空气品质和环境热舒适性尤为重要。针对沈阳某高校示范建筑,分析通风换气技术对其室内环境热舒适性影响,应用Airpak软件进行数值解算,给出室内温度场、速度场和PMV、PPD指标的分布状况。分析不同送风温度、送风风速工况条件下的室内空气温度分布情况,以及PMV、PPD指标对室内环境热舒适性的影响,确定满足环境热舒适性要求的送风工况,为农村被动式住宅的通风换气技术应用提供基础依据。