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People spend nearly 90% of their time daily in various indoors, hence indoor environment is important for mortal survival and activity, which affected human health directly. Indoor particulate pollution has become an issue of increasing concern for human beings. Personnel walking behavior and ventilation mode will significantly affect the transfer characteristics of indoor particles. This paper analyzes the effect of walking process on indoor particle resuspension, and different ventilation modes (ceiling exhaust and slit exhaust) on the removal of indoor particulate concentration in experimental and theoretical models. The results show that the particle diffusion model under walking is in good agreement with the experimental results. The particles with different sizes have different diffusion characteristics during walking due to the surface deposition and resuspension rate. Particles of 1.0–3.0 μm have the fastest velocity and the largest amount in suspension, while the smallest for 0.5–1.0 μm particles. Different ventilation modes have different effects on the removal of indoor particles. The particles attenuation index is higher under slit exhaust mode, therefore the ventilation effect is higher than ceiling ventilation mode.

Understanding the thermal performance of the residential envelope is important for optimizing the indoor thermal environment. In this study, the indoor thermal environment and thermal performance of rural residences housing the elderly was determined through field measurements in Qiqihar in 2017 and 2019. The results revealed that the living room temperatures in more than 50% of homes were below the thermal neutral temperature for the elderly (17.32 &deg, C). Moreover, the indoor thermal environment changed significantly during the day, with the predicted mean vote during the day fluctuating from 2 to 4 units. The air change rate of living rooms in 2017 and 2019 was 0.20&ndash, 2.20 h&minus, 1 and 0.15&ndash, 1.74 h&minus, 1, respectively. Residential ventilation times detected by an air-tightness detector ranged from 0.40&ndash, 1.49 h&minus, 1. Furthermore, infrared thermography (IRT) detected air leakage in the windows of the all houses in this study, as well as thermal bridges and condensation on the exterior walls of several houses. The heat transfer coefficient of the exterior walls of all houses detected by IRT was 0.25&ndash, 0.74 W/(m2&middot, K), and a significant positive correlation was observed between the heat transfer coefficient of the south wall and the window-to-wall ratio. Finally, the heat transfer coefficient of the external walls exhibited a negative but not significant correlation with indoor temperature. This study provides detailed data and guidance for improving the indoor environment of rural houses in severe cold regions.

Indoor humidity levels play an important role on occupants’ health, durability of the building envelope, and energy consumption levels. To achieve a sustainable, durable, healthy, and comfortable building environment, it is essential to maintain proper indoor humidity levels. Hygroscopic materials are typically used as finishing materials in some houses to control humidity, however, there is no criterion established to evaluate the moisture buffering effect of these. In this research, a series of experiments examining the moisture buffering effect of three types of hygroscopic materials were conducted in an actual room using different air change rates, hygroscopic material loading ratios, and moisture loads. A new index is proposed to evaluate the moisture adsorption effect ( MBE a ) and moisture desorption effect ( MBE d ) of hygroscopic materials at the room scale. Using the proposed index of MBE a / MBE d , multivariate linear regression analysis was performed to find the relationship between MBE a / MBE d and the major parameters that influence this. The model results show that the moisture adsorption/desorption effect of the hygroscopic materials in real-world conditions increased exponentially when the ambient air change rate decreased or the loading ratio of hygroscopic material increased.

To study the winter indoor environment in the rural homes with elderly individuals in different climate regions, households with elderly individuals in Qiqihar (northeast China) and Shanghai (southeast China), were selected for questionnaire surveys (50 and 60 households in Qiqihar and Shanghai, respectively) and field measurements (10 and 5 households in Qiqihar and Shanghai, respectively). The field measurements included the monitoring of air temperature, relative humidity (RH), carbon dioxide (CO2), particulate matter (PM) with an aerodynamic diameter of 2.5 μm or less (PM2.5), carbon monoxide (CO), nitrogen oxides (NOx), volatile organic compounds (VOCs), and semi-volatile organic compounds (SVOCs) concentration. The results indicated that elderly individuals in Qiqihar had large temperature steps ranging from 15 to 35 °C between the indoor and outdoor, and experienced unsteady thermal environment, but those in Shanghai experienced low temperature, high RH, and steadier thermal environment. Additionally, the thermal neutral temperatures in Qiqihar and Shanghai were 17.32 °C and 16.91 °C, higher than air temperatures for living-bedrooms/kitchens (14.5 ± 4.3 °C/12.8 ± 4.7 °C) and for living rooms/bedrooms (10.4 ± 1.5 °C/10.5 ± 1.5 °C). Moreover, the older people had higher blood pressure in lower temperature. Qiqihar households showed more serious air pollution than Shanghai. For Qiqihar households, the concentration of PM2.5 and total VOCs (TVOC), which exceeded the standard, accounted for 90%, while PM2.5 concentrations in 4 households were 6 times higher than the standard. This study provides valuable data for future work on environmental risk assessment in elderly households in rural areas.

Appropriately designing buildings in hot and humid climates is challenging when environmental factors and the needs of the building’s occupants are considered thoroughly. Because of the serious issue of climate change, coupled with a scarcity of conventional energy sources and a high demand for better indoor environments, advancements in the design of buildings so that they are environmentally friendly and occupant-friendly houses are indispensable. The application of new building technologies intended for tropical climates is especially needed. Outdoor environmental considerations of available on-site and off-site renewable energy sources must be taken into account when designing buildings. An evaluation of comfortable and healthy indoor environments is also important factors. The optimized utilization of available energy sources is necessary for hybrid building operation. Increasing the energy efficiency of buildings makes operating the building significantly cheaper by lowering the energy consumption which could be sourced on-site. When a building is designed to take advantage of alternative energy sources, the building is energy independent from grid-connected electricity and, thus, is not prone to power failure. Such a building can rely on different energy sources to make the building work as an energy generator. Having energy-efficient and renewable energy-supported building in hot and humid climates reduces the conventional energy consumption of the area in which these buildings are located. It also lowers the energy required from the grid line, thus minimizing grid line stress. From this, greenhouse gas emissions, which contribute significantly to climate change, can be minimized.

China has a vast territory with a variety of climates. Residents living in different climate zones are exposed to different indoor thermal environments in their homes and thus may have various thermal comfort levels. This study conducted a one-year campaign in 157 residential apartments in 12 cities across five climate zones in China by means of indoor thermal environment monitoring and online questionnaires in bedrooms. The study found that the severe cold (SC) and cold (C) climate regions had a warm and dry winter with median air temperature and relative humidity of around 23 °C and 25%, respectively. In summer, the cold climate region had the highest indoor air temperature among all regions. In terms of thermal sensation, more than 85% of residents voted in the middle three categories (slightly cool, neutral, and slightly warm), indicating an overall satisfactory thermal environment in Chinese residential buildings. However, residents in the hot summer and cold winter (HSCW) region reported the highest percentage of “cold” votes (18%) in winter, while those in the cold climate region reported the highest percentage of “hot” votes (18%) in summer. A “seasonal effect” was observed, by which the thermal sensation and clothing insulation in a particular season followed the general air temperature level of that season. The findings of this study are expected to contribute to the design and control of a thermally comfortable environment in residential buildings.

This study attempts to collect more comprehensive data about the indoor environmental quality in urban dwellings with schoolchildren in Beijing, China. For this purpose, indoor air temperature, relative humidity and the levels of indoor chemical and biological pollutants in 14 households were measured in 2013. Results show that, in cold winter, indoor relative humidity was often lower than the comfort limit of 30%, while indoor CO2 concentration was often higher than the acceptable level of 1000 ppm in poorly ventilated homes with high occupant load. Indoor PM2.5 pollution was very severe with the highest level of 523 µg/m3 in living room and 345 µg/m3 in children’s bedroom in winter. Compared with the recommended thresholds, the levels of indoor volatile organic compounds and carbonyl compounds in most homes were low. Cigarette smoke is an important indoor source of PM2.5, formaldehyde, acetaldehyde, acetone and benzene. Also, there are significant correlations between the concentration of total volatile organic compounds and other compounds (acetaldehyde, acetone, benzene and toluene). Furthermore, two phthalates: di (2-ethylhexyl) phthalate and di-n-butyl phthalate were frequently detected in house dust. Penicillium, Cladosporium, and Aspergillus were predominant fungi in indoor air. The fungal pollution levels in different seasons and rooms were also compared.

This paper reported concentration characteristics of thirteen kinds of gaseous carbonyl compounds (CCs) in urban houses with schoolchildren in two different climatic zones of China, estimated schoolchildren’s daily inhalation dose of formaldehyde and acetaldehyde, and then evaluated potential health risks for schoolchildren. Formaldehyde was the most abundant CCs in the houses, following by acetone and acetaldehyde. Mean concentrations of indoor formaldehyde, acetaldehyde and acetone in summer were 39.4 μg/m3, 16.1 μg/m3 and 26.7 μg/m3, which were higher than the concentrations of 21.4 μg/m3, 9.9 μg/m3 and 16.5 μg/m3 in winter. Compared to winter, more kinds of CCs were detected in summer. The significant positive correlations between different CCs indicated CCs were coexisting in indoor environments and released from the same sources. Due to a longer time spent in child’s bedrooms, children’s inhalation doses of formaldehyde and acetaldehyde in child’s bedrooms were much higher than those in living rooms. The impact of formaldehyde exposure in the houses on children’s health was greater than acetaldehyde exposure. The average risk quotients for formaldehyde exposure in winter and summer were 20.74 and 39.34, while 4.65 and 6.97 for formaldehyde exposure. These results supplemented the limited data concerning children’s exposure to CCs and associated health risk in the houses of China.

Indoor thermal environments in residential buildings vary due to differences in the outdoor climates, the envelope thermal properties of the buildings, the types of heating and cooling systems, and adaptive behaviors such as the operation of air conditioners and windows by dwellers. This study comprehensively investigated the thermal environments in 46 apartments in nine cities across five climate zones in China via on-site monitoring of the indoor air temperature, the relative humidity, and the air conditioner and window use for one year. The results demonstrate large variations in the thermal environments among the cities. During the heating period, the interior air in Urumqi and Shenyang was overheated (>24 °C) 43% and 59% of the time, respectively, while the indoor air temperature in Chongqing can be lower than 10 °C. As the outdoor climate became warmer, the temperature difference between indoors and outdoors decreased due to the increased window-opening duration. In summer, the indoor humidity ratio was higher than 12 g/kg for a long time in all cities except Urumqi. A clear linear positive correlation between the indoor and outdoor humidity ratios was identified until the indoor humidity reached 18 g/kg, which was due to the increased use of air conditioners. The results of this study provide an updated overall picture of the thermal environments in Chinese residential buildings.

Based on Chinese statistics, unit energy consumption for 277 Chinese cities was clarified over the period of 2002–2012. The meter reading of energy consumption showed that annual energy consumption was recorded from 10 to 30 GJ, excluding the energy consumption by the district heating. Roughly one third of the energy consumption was used for cooking, and another one third was used for space heating, cooling, and hot water supply, and the final one third was used for the other purposes. The results of the detailed measurement indicated that in the eight apartments without district heating, the annual energy consumption varied from 8 to 32 GJ. Also, it was observed that there are large variations in the structure of end usage. That implies that there is room for further improvement in saving energy.

The Great East Japan Earthquake occurred on March 11, 2011. The resulting tsunami caused extensive damage in seaside cities along the Pacific coast of the Tohoku district of Japan. The long-term presence of water in crawl spaces and wall cavities causes elevated humidity and fungal contamination, with potential implications for affecting the health of the occupants. In order to clarify the actual indoor environment and occupants' adverse health effects, a cross-sectional study in the flood-damaged homes located in the flooding areas was conducted from July to December of 2012. We randomly selected 234 dwellings, and a total of 170 responses were obtained for a main survey (Phase 2). Indoor environmental problems related to dampness and mould growth were observed in flood-damaged homes after the flooding. Exposure to poor indoor environmental quality after flooding was positively associated with adverse health effects. Persistent health and environmental problems were recognized within six months after flooding and the long-term effects of mould growth after flooding was observed at least for one year.

This paper presented the exergoeconomic evaluation of the developed desiccant-evaporative air-conditioning system. The developed system was evaluated based on the steady-state conditions at different regeneration and reference temperatures. The exergoeconomic evaluation method was implemented to the system components and the whole system to evaluate the exergy efficiency, exergy destruction ratios, cost rates, relative cost differences and exergoeconomic factors. The regeneration and reference temperatures affected the exergy efficiencies, exergy destruction ratios, cost rates, relative cost differences and exergoeconomic factors. The desiccant wheel, heating coil and evaporative cooler had a high cost rate (investment cost, operation and maintenance cost, and exergy destruction cost). The exit air fan, outdoor air fan and evaporative cooler had a high relative cost difference. The exit air fan, outdoor air fan and secondary heat exchanger had a high exergoeconomic factor. Replacement of the desiccant wheel with a higher dehumidification performance could decrease the high cost rate. A higher efficiency evaporative cooler and heating coil were needed. Cheaper air fans (outdoor air fans and exit air fans) were needed.

The new energy policy in Japan is implemented by renewable energy resources which are given a large slice of the total for their contribution to energy sources. In addition, there is a government plan to minimize, if not to eliminate nuclear power sources. Building sector energy consumption is increasing every year, hence, utilization and development of alternative energy sources and technologies to support the requirements of every house are important. Numerical performance evaluation of the alternative energy and technologies supported single family detached house was conducted in a transient system simulation (TRNSYS) program to evaluate its performance and energy requirements, and to test the cases for a possible upgrade to an energy generating house. The evaluation of the house performance is compared for possible application to the situation in different areas of Japan. 82.6% of the total primary energy supply could be supported by renewable energy sources – solar energy and biomass fueled auxiliary heater. 69.7% of the consumed energy is electricity; grid line electricity is still needed in the present installed photovoltaic roof tiles of the house. Solar energy collection can support up to 26% of the primary thermal energy requirement of the single family detached house. The remaining 70% should be supported by the back-up water heater of which fuel can be sourced from different sources such as biomass, kerosene, etc. In general, making a house yield higher thermal performance by employing energy conservation measures (ECM) coupled with the utilization of different alternative energy sources readily available in the house’s vicinity has an impact on the reduction of the house’s energy consumption. In addition, application of new technologies which could be supported by different energy sources has an impact on the diverse utilization of the available energy sources in the house’s vicinity.

UNLABELLED Thermal conditions and indoor concentrations of aldehydes, volatile organic compounds (VOCs), and NO2 were investigated in 19 occupied temporary houses in 15 temporary housing estates constructed in Minamisoma City, Fukushima, Japan. The data were collected in winter, spring, and summer in January to July 2012. Thermal conditions in temporary log houses in the summer were more comfortable than those in pre-fabricated houses. In the winter, the indoor temperature was uncomfortably low in all of the houses, particularly the temporary log houses. Indoor air concentrations for most aldehydes and VOCs were much lower than the indoor guidelines, except for those of p-dichlorobenzene, acetaldehyde, and total VOCs. The indoor p-dichlorobenzene concentrations exceeded the guideline (240 μg/m(3)) in 18% of the temporary houses, and the 10(-3) cancer risk level (91 μg/m(3)) was exceeded in winter in 21% due to use of moth repellents by the occupants. Indoor acetaldehyde concentrations exceeded the guideline (48 μg/m(3) ) in about half of the temporary houses, likely originating from the wooden building materials. Indoor NO2 concentrations in the temporary houses were significantly higher in houses where combustion heating appliances were used (0.17 ± 0.11 ppm) than in those where they were not used (0.0094 ± 0.0065 ppm). PRACTICAL IMPLICATIONS In the winter, log-house-type temporary houses are comfortable in terms of humidity, dew condensation, and fungi based on the results of questionnaires and measurements, whereas pre-fabricated temporary houses are more comfortable in terms of temperature. In the summer, log-house-type temporary houses are comfortable in terms of temperature and humidity. More comfortable temporary housing in terms of temperature and humidity year-round is needed. Indoor air concentrations of p-dichlorobenzene and NO2 were quite high in some temporary houses due to occupants’ activities, such as use of moth repellents and combustion heating appliances. The government should provide recommendations for safe use of temporary houses by occupants.

The developed desiccant heating, ventilating and air-conditioning (DHVAC) system was evaluated using the exergetic method under controlled environmental conditions to determine the performances of the whole system and its components. Percentage contributions of exergy destruction of system components at different regeneration temperatures and reference temperatures were determined. Exergy destruction coefficient of different components at different regeneration and reference temperatures was presented. It was shown that exergetic performances varied with respect to the regeneration and reference temperatures. The exergetic performances based on thermal, electric, total exergy input, first definition and second definition efficiencies were shown. Based on the results, reference and regeneration temperatures affected the determination of the system performances and its components. It was shown that air heating coil (AHC), air fans and desiccant wheel (DW) contributed to large percentage of exergy destruction. Hence, the mentioned components should be given attention for further improvement in the system performances.

The building sector is one of the largest end-users of primary energy sources. One of the main usages of its energy is for the maintenance of indoor environmental conditions—thermal comfort and air quality. In this regard, the selection, design and installation of the heating, ventilating and air-conditioning systems in buildings and houses are very important when considering the reduction of energy consumption and, at the same time, with the provision of the required comfortable indoor thermal environment and healthy indoor air. The desiccant heating, ventilating and air-conditioning system is one of the alternative heating, ventilating and air-conditioning (HVAC) systems for providing the required indoor thermal environment and air quality. The system can provide the required thermal comfort and air quality by means of controlling the air temperature, humidity, as well as indoor chemical and biological contents. This type of system can utilize diverse sources of energy, which is very important for the optimization of on-site and off-site available alternative energy sources. As the advancement of the desiccant heating, ventilating and air-conditioning system (DHVAC) becomes globally established by the progress in different research deliverables, designs, installations and evaluation methods, it is expected that the system will become one of the most important alternative systems for the maintenance of indoor thermal environment comfort and air quality when considering the reduced reliance on conventional energy usage.

The desiccant heating, ventilating and air-conditioning system (DHVAC) consists of many heat and mass transfer components operating together with air fans. The performance test using the multiple tracer gas dilution method is important for knowing the internal and external flow rates, including the air leakages. The results of the test show the actual internal air flow rates and the sources of air leakage, and also show the interaction of air in the air-conditioned lecture room and in the mechanical room. The performance test using the multiple tracer gas dilution method in air flow and air leakages is important for a detailed evaluation of DHVAC.

The developed desiccant-evaporative air-conditioning system was evaluated using the exergetic method under controlled environmental conditions to determine the performances of the whole system and its components. Percentage contributions of exergy destruction of system components at different regeneration temperatures and reference temperatures were determined. Exergy destruction coefficient of different components at different regeneration and reference temperatures were presented. It was shown that exergetic performances varied with respect to the regeneration and reference temperatures. The exergetic performances based on thermal, electric, total exergy input, first definition and second definition efficiencies were shown. Based on the results, reference and regeneration temperatures affected the determination of the system performances and its components. It was shown that air-heating coil, air fans and desiccant wheel contributed to large percentage of exergy destruction. Hence, the mentioned components should be given attention for further improvement of the system performances.

Dust particle which includes corpses and feces of the mite, animal dander, cockroaches, and mould spores can reach the lung of human and then trigger asthma disease easily. In this research, experimental studies were carried out in order to examine particle removal efficiency in a room with two ventilation systems: a ceiling exhaust system and a slit exhaust system. The results indicated that there was no clear relationship between removal efficiency and two different outlet locations. Also, from the results after the decay, the particle count in the case of the ceiling exhaust was higher than that in the case of the slit exhaust.

The purposes of this study were to investigate and analyze the actual conditions of the residential energy consumption, and hence to ascertain what would be the important factors that influence the annual energy consumption in four Chinese cities. The questionnaire surveys revealed building characteristics, housing appliances, household characteristics, indoor environment and aspects of life style, during winter and summer seasons. The energy consumption analyses showed that the average annual energy consumption of households in Chongqing reached 41.1 GJ which was the largest among all households in the investigated cities. The influence factor analyses showed that the important influence factors were city location, floor area, CDD and water heater type. The standards “ Thermal design code for civil building ”, GB 50176-93 helps to save energy. The households equipped with solar water heater (SWH) consumed less energy, however, its possession rate was low because of the poor quality in the Chinese market. Thus, corresponding policy steering mechanisms of SWH are needed for energy saving. The annual energy consumption for water heater in Shanghai, Chongqing and Changsha was 6.7, 8.3 and 5.7 GJ, accounted for 23%, 20% and 18% respectively. The more energy would be saved if more households use solar water heater.

The purpose of this study was to reveal the energy use and indoor environment characteristics of twelve households located in six cities in China, including daily use of gas and electricity, temperature and humidity throughout a year. The energy uses for district heating and hot water were not included. The investigated houses were separated into two groups, namely Group 1 with domestic heating, and Group 2 with district heating. The analysis showed that the energy use of Lighting and Audio visual & information for each house is not very different during the four seasons. Annual energy use varied from 13.3 to 32.4 GJ in Group 1. The energy use of House 05 was 32.4 GJ/year, which is the highest in Group 1, the space heating reached 18.5 GJ/year, accounting for 57% of the total. Energy use of House 01 increased in winter and summer, which is attributed to the use of heating in winter and cooling in summer, respectively. Annual energy use varied from 2.9 to 17.0 GJ in Group 2. Almost no change of energy use was found for the houses in Group 2 during the four seasons, but a big difference of average indoor temperature was found in the coldest days between the houses in Group 1 (around 10 °C) and Group 2 (around 20 °C), while the difference was small in summer.

This paper shows the numerical investigation of the developed solar-desiccant cooling system applied in the East Asian climatic conditions with two different desiccant wheel coating materials – the Silica-Gel (SiO2) and the Titanium Dioxide (TiO2). The developed and validated numerical model of the system is currently used in the present study incorporating the two new materials in the desiccant wheel. The system was applied in temperate climate (Beijing and Tokyo), subtropical climate (Taipei and Hong Kong) and tropical climate (Manila and Singapore). The study showed that the specification of the solar-desiccant cooling system varies depending on the climatic conditions. It showed that the required flat plate collector area was getting larger from the temperate climate to the tropical climate. The storage tank requirement was getting bigger in the tropical climate compared to the subtropical and temperate climate. The volumetric flow rate of air was getting higher from temperate climate to tropical climate. In the comparison of the two materials, it was found that the Titanium Dioxide (TiO2) can support lower indoor temperature and humidity ratio than the Silica-Gel (SiO2) with the same specification of the solar thermal system and desiccant cooling system. In general, the solar-desiccant cooling system can provide the required indoor temperature and humidity ratio. However, for the hot and humid climate such as in tropical, large size of the solar thermal system is needed. In addition, higher volumetric flow of air to support the high cooling load is required. With regard to the new material, Titanium Dioxide, it is proven to be a good alternative material since it can provide lower indoor temperature and humidity ratio with higher cooling performance than the Silica-Gel.

Since indoor particles accumulate on the floors easily, there is a high possibility of allergic reactions in child whose breathing zone is near the floor surface. Ventilation is one of the best ways to remove indoor particles. The aim of this study is to clarify the diffusion characteristics of indoor particles in different ventilation strategies room by experiments and CFD. Comparison of the number of particle in experimental monitoring point shows that the number of particle in the ceiling exhaust was a little higher than the slit exhaust ventilation strategy. CFD simulations concerning diffusion fields completed. From the data we can conclude that slit exhaust ventilation strategy will produce less indoor particles in the room to compare ceiling exhaust ventilation strategy.

Based on the fact that the house dust usually falls on the ground, the floor level slit exhaust ventilation system including inlet located at the ceiling and outlet of slit exhaust installed at corner between wall and floor was considered. Experiments and simulations were performed to investigate the flow and diffusion fields that are affected by this floor level slit exhaust ventilation system. The characteristics of airflow with experiments and computation fluid dynamics (CFD) are generally similar except airflow at the location of impinging flow and the location right below the inlet. Riboflavin particles were used as the house dust. For the spatial distribution of riboflavin particles in the ventilation system before operation, due to the influence of gravity, different sizes of particles show smooth decay curve. After floor level slit exhaust ventilation system is operated, the decay rate of the particles becomes faster than that after the ventilation system is powered on, and the particles with diameter of 0.5–3.0 μm in the experimental data and calculated values show good agreement.

It is widely known that the problem of low or high indoor humidity environment has various adverse effects on occupant’s health, durability of the building envelope and energy consumption. In order to create comfortable and healthy indoor environment, it is necessary to maintain the indoor humidity steady in a correct level. Hygroscopic interior material can adsorb and desorb moisture from surrounding air, adopting this material is an energy-efficient way to moderate indoor humidity variations and thus it has been applied as finishing materials in some buildings. However, there is no criterion to evaluate the moisture buffering effect of applying hygroscopic material. In this research investigation, a series of experiments with different applying parameters were designed and carried out in a climate-controlled test chamber. The purpose of this study is to quantitatively evaluate the moisture buffering effect by applying hygroscopic material, as well as to understand the humidity distribution of a hygroscopic material furnished room. Experimental results showed that the effects of moisture adsorption/desorption decreased exponentially when the ambient air change rate per unit area of hygroscopic material increased.

In this paper, a year filed survey has been conducted in eighty households which are located in six different climatic districts in Japan from December 2002 to November 2003. The investigated contents included energy consumptions for different end users, indoor climate conditions, thermal performance of the buildings, lifestyles of residents, etc.. In addition, statistical analyses were carried out using the quantification method I, so as to find out the influential factors that determine residential energy consumptions.

The purposes of this paper are to analyse energy consumption characteristics and to find out influence factors of residential energy consumption in summer in typical cities of China. The investigated residences were located in seven cities of five architecture thermotechnical design zones. Questionnaire surveys revealed housing unit characteristics, household characteristics, the possession and utilization of domestic energy consuming appliances and indoor thermal environment in summer. Energy consumption analyses show that summer energy consumption amounts in different cities bear distinct regional characteristics: the household amounts of electricity use are largest in Hongkong, and the values are smaller but still at a high level in Beijing, Shanghai and Changsha, and at the smallest level in Kunming, Harbin and Urumqi, while the difference in gas use is small among these cities. Influence factor analyses show that city locations, housing unit characteristics, the utilization of space coolers and water heaters, household characteristics, and subjective evaluation of indoor thermal environment all contribute to the residential energy consumption in summer when taking all the families in the seven cities as the sample collectivity, while detail analyses for separate cities shows each city has its own characteristics. In Shanghai, the satisfaction rate of thermal environment, the possession and operation of air conditioners and housing unit characteristics greatly affect the summer energy consumption, but the electrical fan is judged as the non-influence factor, while in Urumqi, the possession and operation of electrical fans and the categories of water heaters have remarkable effect, and the influence of housing unit characteristics is also distinct, but the number of air conditioners and their usage contribute little to energy use due to the cool climate.

A system has been developed for predicting snow distribution in built-up environments. This system combines a mesoscale meteorological model that predicts precipitation, including snowfall in an area, and a Computational Fluid Dynamics (CFD) model that predicts snow phenomena on building scale. The system focuses on snow distribution around buildings, which often leads to snow disaster and snow-related difficulties in urban areas. It can be used for predicting snow distribution due to snowfall and snowdrift in a development area and is expected to be a useful design tool for city and architectural planning in snowy regions. This paper outlines the system and examines its performance by comparing its results with measured data. The snowdrift patterns, i.e. erosion around the upwind corners and deposition in front of and behind a building, obtained by the present model show good correspondence with those obtained from field observation. However, the model under-predicted the decrease of snow depth near the building. Further investigations required to comprehensively evaluate the prediction accuracy of the system are discussed.

This study aims to investigate and clarify the effects of roadside trees and automobiles on airflow distribution, turbulent diffusion of air pollutants and thermal environment within street canyons by means of the field measurements. The detailed field measurements were carried out at two streets with different densities of roadside trees and traffic volume in the central part of Sendai city, Japan. The microclimates and NOx concentrations as well as traffic volume were measured. The effects of roadside trees were investigated by comparing the results measured at the two streets. The results clearly showed that thermal environment has been improved but NOx concentration also increased simultaneously by the roadside trees. The more the number of moving automobiles were, the higher the NOx concentration was at the downstream of the circulating flow within street canyons due to the gas emission from automobiles.

A high or low humidity environment is related closely to not only many health problems, but also has great influence on the construction durability and energy consumption. It is very important to control humidity level, in order to achieve a healthy and comfortable indoor environment. However, various problems of the air humidity in inhabited dwellings are not yet taken serious consideration in China. Moreover, there is hardly any information available regarding the actual humidity environment in Chinese residential houses. For this reason, it is difficult to select appropriate moderate moisture strategies to maintain a harmonious indoor humidity level. The current authors carried out a field measurement survey on indoor thermal environment in nine Chinese cities. Based on this investigation, the purpose of this present study is to develop a database of actual indoor humidity conditions for moisture moderate design, through which the characteristics of indoor humidity environment in Chinese residential houses can be identified and clarified. The results demonstrated that the indoor humidity level is too low with the relative humidity falls below 20% in some cities where residences equipped with central heating system in winter. On the other hand, indoor humidity is very high with the relative humidity beyond 80% in some cities where residences have inadequate heating and high outside humidity ratio in winter. The severe indoor humidity environment indicated that the moisture level in the residential houses of China should be mitigated and controlled in order to achieve a sustainable and healthy indoor environment.

This study evaluated various ventilation strategies for efficiently removing house dust in the indoor environment. Experiments and simulations were performed to study the flow and diffusion fields that are affected by different locations and shapes of outlets. In this study, two kinds of ventilation strategies were considered i.e. ceiling exhaust and slit exhaust. In each case, experimental measurements showed that the characteristics of airflow within the whole room are generally similar except for airflow close to the outlet. CFD flow field and diffusion field simulations were also made. The CFD characteristics of airflow were similar to the experimental results. In the simulations, the volume-average concentration of house dust within the whole room decreased gradually. From the results, a conclusion can be drawn that the volume-average concentration of house dust within the whole room is lower in the case of slit exhaust than ceiling exhaust. After a ventilation period of 30 minutes the CFD r...

In this paper, experiments and simulations investigating the moisture buffering of the gypsum boards are described. A test chamber was used for the experiments. The gypsum board was installed on the interior surface in the test chamber. This chamber was located in a climate chamber. The ambient condition of the chamber was controlled at constant temperature and humidity. In the experiment three cases of ventilation rate, no ventilation, 1.0 air change per hour and 5.0 air changes per hour, were investigated. In the experiment the relationship between moisture buffering and volume rate of the materials, various area and locations of the gypsum boards on the surrounding walls were investigated. Simulation studies were also carried out to compare with the measurement results. Experimental data sets for boundary conditions, ventilation rate, amount of moisture production, ambient air temperature and humidity, were provided as input data for simulations. Six simulation programs were used in this project. Simulation results in some of the cases showed comparatively good agreement with the measurement results. However, deviations between experimental values and simulation results in other cases were large.

This paper presents the investigation of the prediction models for snowdrift around a building using CFD. Special attention is paid to prediction accuracy of the modeling for erosion and accumulation on snow surface. The computations are applied to the snowdrift around a cubic building model. The results obtained by CFD models are examined by the comparison with the results of the field measurement and the wind tunnel experiment. It is confirmed that the snowdrift patterns predicted by all proposed models correspond with those of the field measurement and the experiment. However, some differences are observed in the predicted snow depth near the building among the different modeling methods.

Based on the energy consumption database of nationally residential houses in various districts of Japan, indoor humidity environment was analyzed. In winter and summer seasons, the statistical values of temperature, relative humidity, absolute humidity and the absolute humidity difference between indoor and outdoor were calculated for each house. In addition, the relations between these statistical values and the level of thermal insulation or airtightness, as well as the possibility of fungal damage were examined.

The accuracy of the canopy models for reproducing the aerodynamic effects of trees based on k–e model was examined for the CFD prediction of wind environment at pedestrian level. After reviewing the previous researches on modeling canopy flows, two types of canopy models were selected. In addition, the model coefficients adopted in the extra term added to the transport equation of turbulence energy k and energy dissipation rate e, were optimized by comparing numerical results with field measurements. r 2008 Elsevier Ltd. All rights reserved.

This study aims at clarifying the regional heat balance characteristics in an urban space of a city. CFD analyses of mesoscale climates of Tokyo, Sendai and Haramachi were carried out. The influence of regional characteristics on urban climates was examined, based on the results of CFD analyses, by considering the heat balance mechanism in the central part of each city. It was confirmed that the factors greatly contributing to air temperature increasing and decreasing in each city was different. Furthermore, the spatial distribution of heat budget inside Sendai city was drawn, as “Heat Balance Map”. The map illustrated the areas where influence of sea breeze was significant in contrast with heat generated from ground surfaces and anthropogenic heat release in this city.

A long-term field survey was conducted with six buildings in order to investigate how the occupants adapt to the indoor climate in office buildings in Japan. More than 5000 questionnaires and corresponding indoor temperatures were collected. Clothing adjustment was observed to be related to outdoor temperature and indoor temperature, as well as dress codes. No considerable differences were found on the thermal perceptions between two groups of buildings, which provided different levels of opportunity for controlling indoor climate. With both groups, the preferred SET* was always close to 26 °C. The comfort temperature was estimated from the results of clothing adjustment and the preferred SET*. The gradient of the comfort temperature to outdoor temperature was found to be between the adaptive model for centralized HVAC and for natural ventilation. It could be caused by that the major part of the occupants in the present study had more opportunity to control their thermal conditions than in the centralized HVAC buildings (i.e. operable windows, controllable HVAC or personal fans).