Indoor Thermal Conditions Research Articles

Influence of cross-ventilation cooling potential on thermal comfort in high-rise buildings in a hot and humid climate

The rising cooling energy demand, caused by the increase in global average temperature and the frequency of heat waves, is currently leading to a significant increase in global electricity consumption. Passive cooling strategies, such as ventilative cooling, can provide acceptable indoor thermal comfort with no or minimal energy consumption, offering an alternative to air conditioning systems in buildings. This paper investigates the effectiveness of natural ventilation in an iconic post-modernist high-rise building in India: Charles Correa's Kanchanjunga Apartments. The research, employing CFD simulation paired with building energy simulation, demonstrates how cross-ventilation can improve the ventilative cooling efficiency in buildings, ensuring affordable indoor thermal conditions even in adverse climatic conditions like the Indian one. Thanks to night-time structural cooling, a maximum reduction in the operative temperature of up to 5.3 °C was achieved compared to the scenario without natural ventilation and up to 6.4 °C compared to the outdoor temperature peak on the hottest day. Consistently with the Indian Model for Adaptive Comfort, cross-ventilation ensures a reduction in discomfort hours of up to 58 % on the hottest day and a total reduction in discomfort hours on a typical monsoon and winter day. The paper aims to assist architects and policymakers in quantifying the cooling potential of natural ventilation in high-rise buildings, suggesting passive solutions for cooling energy saving.

Green roofs and thermal comfort: a comparative study of soil layers’ seasonal thermal performance integrated with ventilation in hot climate

ABSTRACT Green roofs’ (GR) positive impact on indoor thermal conditions in hot areas may have possible negative impacts during hot and cold weather. Most previous studies have focused on GR’s positive effects as a standalone strategy without mitigating these side effects of GR application. This study contributes to a more comprehensive understanding of the impact of GR and how to mitigate the negative aspects by integrating it with other passive techniques (natural ventilation and thermal insulation). Therefore, this study experimentally compares the seasonal impact of various soil layer configurations, integrated with natural ventilation, on improving Indoor Thermal Comfort (ITC) throughout the day in summer and winter. Field experiments were conducted using two identical validated test boxes. The results revealed that clay soil reduced Indoor Air Temperature (IAT) during the daytime in summer by up to 4.7 and 4°C for low and high soil thickness, respectively. Increasing clay soil thickness improved average IAT during the daytime in summer and winter by up to 6.49% and 2.61%, respectively. Additionally, adding thermal insulation is preferred in winter, while uninsulated soil had a slight positive effect on IAT and Indoor Relative Humidity (IRH) in summer. The use of natural ventilation at night and closed-ventilated systems during the daytime in summer and winter is recommended. Clay soil could save cooling and heating energy by up to 34.8% and 12.18%, respectively. These findings might inform designers by adjusting different GR soil parameters and the importance of natural ventilation in improving multi-seasonal thermal and energy performance.

Thermal Comfort Comparison and Cause Analysis of Low-Temperature High-Humidity Indoor Environments of Rural Houses in Gansu Province, China

Low temperatures and high humidity often occur in the northern basins and mountainous regions of China. This research reveals a common winter indoor environment in this rural areas characterized by low-temperature and high-humidity indoor thermal conditions. Improving this environment directly with equipment would inevitably result in significant energy consumption. Therefore, comprehending the thermal performance mechanisms of different structural building materials is of vital importance as it provides crucial baseline values for environmental improvement. This study conducted a survey utilizing user questionnaires, resulting in the collection of 214 valid responses. Additionally, a local experiment regarding thermal comfort was conducted. Simultaneously, this study monitored the indoor physical environments of these houses (a sample of 10 rooms was taken from earth houses and 12 rooms from brick houses). Parameters measured on site included air temperature, relative humidity, light illumination, and CO2. The results showed that the humidity inside the earth houses is more stable and regression models can be developed between thermal sensations and temperature for long-term residents. The residents of these earth houses are more sensitive to temperature step. In contrast, the residents of brick houses, experiencing greater environmental variability, demonstrated lower sensitivity and greater adaptability to temperature changes. In addition, heating from bottom to top is more comfortable and healthier for the residents of brick houses in Gansu. Moreover, it is more favorable for the inhabitants’ livelihood to regulate the temperature steps to a maximum of 4 °C. This study provides valuable reference information for the future design of houses in low-temperature and high-humidity environments.

Thermal conditions in workspace centre and adjacent to inclined glazed façade of a green-certified office building in the tropics

This paper aims to assess the effectiveness of incorporating inclined glazing with double low-emissivity (low-e) glazing, in glazed, green-certified office buildings in Malaysia. The study was conducted in an open workspace facing south and west. Comparisons were conducted between measurements made on weekdays when cooling systems were active and weekends when they were not in use. The analysis considered two different zones based on the proximity to the glazed facade: the adjacent zone and the central zone. The thermal performance of the glazed facade and the indoor thermal conditions were measured from July 25th to August 30th. The findings indicate that the building successfully maintains indoor air temperature within the recommended thermal range of 23 °C–26 °C, as specified by the Malaysia Standard. However, it was noted that the air velocity fell below the required level for optimal indoor air circulation. Measuring the globe temperature showed a remarkable difference, with the adjacent zone experiencing 4.1 °C higher temperatures due to radiant heat from the glazing. Additional research is suggested to assess the effectiveness of inclined and double low-e glazing in hot–arid climates like Saudi Arabia.

A simulation-based evaluation of using PCMs in buildings for energy efficiency under different climate conditions

Today, majority of energy consumed in buildings is used to provide thermal comfort conditions. Reducing heating and cooling loads to provide comfort conditions in buildings is possible by taking the right passive design decisions concerning the variables that affect these loads. The building envelope which seperates indoor environment from the outdoor environment and affects the development of indoor thermal comfort conditions is the most important determining factor for energy loads in buildings. In this study, after applying PCM on the building envelope and inner walls and inner floors annual heating, cooling and total energy consumptions and indoor environment comfort conditions in the zones were evaluated. The study was done for Istanbul representing temperate humid climatic zone and for Diyarbakir representing hot-dry climatic zone in the same degree-day region according to the TS825 standards. The residential building simulated for calculations is a 3 storey building with a rectangle floor plan and flat roof and the dimensions of these buildings are 10 m × 30 m × 9 m. The building comprises 9 zones and the building coverage is 300 m2. In order to reduce the difference in energy consumption and thermal comfort conditions among the zones due to their different locations, PCM was applied on inner walls and inner floors in addition to the building envelope to develop a range of alternatives. Annual energy performance evaluation and calculation of daily operative temperature values for January 21 which represents the heating period and July 21 which represents the cooling period were done by the EnergyPlus simulation tool. According to the calculations, the total energy load of the building in the A4.2 alternative where PCM was applied on the building envelope and on inner walls and inner floors was reduced by 11.96 % and 9.69 % in Istanbul and Diyarbakır respectively. With the alternatives, differences in energy consumption among the zones were reduced but not eliminated. Operative temperature values in the zones changed by 1.04 °C – 3.32 °C in Istanbul and by 0.87 °C – 1.16 °C in Diyarbakır with the PCM application contributing to the improvement of indoor comfort conditions.

A Comparative Analysis of Outdoor Thermal Comfort Indicators Applied in China and Other Countries

Outdoor thermal comfort is an important criterion for evaluating the quality of outdoor activity environments and is also a significant indicator for assessing sustainable building design. Over the past century, more than 165 indoor and outdoor thermal comfort indexes have been developed to define human thermal comfort conditions under various circumstances and to quantify indoor and outdoor thermal environmental conditions. However, in the process of outdoor thermal comfort indicators becoming widely used worldwide, it remains a pressing research issue to compare the current state of application in China and other countries, identify the key areas of application for both sides, and outline the trends in outdoor thermal comfort index application. This study analyzed 346 articles on outdoor thermal comfort indicators. Employing bibliometric methods, we outline the general landscape of outdoor thermal comfort index applications in China and other countries. Additionally, we utilize comparative analysis to uncover similarities and differences in the research focus on outdoor thermal comfort. The research findings indicate the following: (1) Compared to China, other countries started outdoor thermal comfort index application research earlier. Their papers have higher average citation counts and engage in close academic collaborations. However, the quantity of published papers is fewer than in China. (2) The top five frequently used indexes in both China and other countries are PET (including mPET), UTCI, PMV, SET* (including OUT_SET*), and THI (including DI). China tends to use PET and UTCI more frequently than other countries. (3) The potential future directions for outdoor thermal comfort index applications in both China and other countries include: “monitoring and controlling regional outdoor thermal comfort at the temporal and spatial scales”, “multi-factors coupling effects on outdoor thermal comfort”, “human health assessment and prediction based on outdoor thermal comfort”, and “utilizing computational algorithms to calculate outdoor thermal comfort”. This study can serve as a reference for researchers and designers in the industry, contributing to the creation of sustainable outdoor environments.

Data-driven model for predicting indoor air quality and thermal comfort levels in naturally ventilated educational buildings using easily accessible data for schools

Modeling indoor air quality and thermal conditions in educational buildings is significant for protecting students' health, well-being, and productivity. The predictive models in existing studies were mainly built and applied in controlled environments with HVAC systems. These models did not involve occupant-related factors, had limited scope in a single building or space, and required indoor environmental monitoring data for the model input. This limits the applicability and generalization ability of the model in a large number of schools relying on natural ventilation, where indoor air quality and thermal conditions are significantly affected by occupants’ activities and ventilation practices. Hence, this paper proposes a methodology to develop a data-driven model for predicting the level of indoor air quality and thermal comfort in naturally ventilated educational buildings, and identifies the key influential factors. The model was developed using the class-weighted random forest algorithm with data collected from a large measurement campaign. The developed model demonstrated good accuracy, generalization ability, and robustness. The analysis concluded that occupancy, windows and doors operation, and outdoor environmental parameters are key factors must be involved, whereas building characteristics have no practical contribution to the prediction. The model inputs are easily accessible data for schools. Once the model is developed with data collected from an initial measurement campaign in representative educational buildings, it can be used in all local schools without requiring monitoring sensor networks, thereby rendering a “cost-effective” way of assessing indoor air quality and thermal comfort to help relevant stakeholders improve building management practices in schools.

A comparative study of the whole life carbon of a radiant system and an all-air system in a non-residential building

There is an urgent need to reduce carbon emissions from the building sector. This study focused on the whole life carbon of a building’s heating, ventilation, and air conditioning system. A methodology to compare the whole life carbon of different HVAC systems was proposed and used in a case study with boundary conditions in Denmark. All-air system and radiant systems were compared, as they have different working principles and the potential for differences in both their embodied and operational carbon. The radiant system was a Thermally Active Building System (TABS), and the all-air system was a packaged variable-air-volume system with reheat. The building model was based on the medium-sized office of prototype buildings developed by the U.S. Department of Energy. Life cycle stages of the building were classified based on EN15978:2011. Two models, one for dynamic building simulation and the other for measuring the mass of materials (e.g., concrete), were adopted in a novel approach. The operational carbon of the HVAC systems was calculated under very similar indoor thermal comfort conditions. The whole life carbon was 10.1 kgCO2-eq/m2/year and 9.0 kgCO2-eq/m2/year for the all-air system and TABS, respectively. Compared to the all-air system, TABS reduced annual total primary energy use by 34% and whole life carbon by 11%. If dynamic carbon intensity of the grid were to be implemented, further reduction of carbon emission is expected with TABS, owing to its flexibility in operation with the activated thermal mass.

Optimizing automated shading systems for enhanced energy performance in cold climate zones: Strategies, savings, and comfort

Enhancing urban sustainability requires innovative strategies to improve energy performance while maintaining occupant comfort in new and existing buildings. Buildings located in cold climate zones with high glazing-to-wall ratios often face unwanted solar gain and heat loss that, in turn, negatively impact building energy performance. Though automated shading systems effectively reduce excessive indoor solar gain in warm climates, a research gap exists regarding their ability to enhance building energy performance in heating-dominant climates. This paper investigates automated shading implementation for cold climate zones and develops a novel cold climate optimized sensorless control strategy for interior roller shades. A field study was conducted to assess the impact of roller shade operation on indoor thermal conditions. Results from the field study showed that the prototype roller shades operating on the developed control strategy reduced daytime indoor peak temperatures during the summer season to 26.4 °C ± 0.5 °C from 30.0 °C ± 1.9 °C and 28.5 °C ± 1.2 °C for the unshaded and shaded static operation baseline scenarios, respectively. During winter season tests, shade deployment reduced the overnight indoor cooling rate from 0.60 °C/hr ± 0.30 °C/hr and 0.42 °C/hr ± 0.18 °C/hr. A mathematical model was also developed to estimate shading system energy performance based on user-defined building specifications and weather-related variables. It was found that automated shading systems are suitable for use as a green retrofit strategy for cold climate zone buildings. The technology exhibited a payback period range of approximately 5–15 years, depending on factors such as glazing type, glazing orientation, solar exposure, and local climate conditions. Findings from both the simulation and prototype field study support the use of cold climate-optimized automated shading systems to improve overall building energy performance - reducing both building heating and cooling-related energy consumption.

The Chinese thermal comfort dataset

Heating and cooling in buildings accounts for over 20% of total energy consumption in China. Therefore, it is essential to understand the thermal requirements of building occupants when establishing building energy codes that would save energy while maintaining occupants’ thermal comfort. This paper introduces the Chinese thermal comfort dataset, established by seven participating institutions under the leadership of Xi’an University of Architecture and Technology. The dataset comprises 41,977 sets of data collected from 49 cities across five climate zones in China over the past two decades. The raw data underwent careful quality control procedure, including systematic organization, to ensure its reliability. Each dataset contains environmental parameters, occupants’ subjective responses, building information, and personal information. The dataset has been instrumental in the development of indoor thermal environment evaluation standards and energy codes in China. It can also have broader applications, such as contributing to the international thermal comfort dataset, modeling thermal comfort and adaptive behaviors, investigating regional differences in indoor thermal conditions, and examining occupants’ thermal comfort responses.

Mitigating undercooling and overheating risk in existing desert schools under current and future climate using validated building simulation model

In Palestine and neighboring regions, buildings are constructed without insulation and mechanical heating and cooling systems, leading to significant thermal discomfort for occupants. To address this issue, the paper introduces a robust methodology that utilizes a validated building simulation model (BSM) created based on hourly indoor air temperature to assess indoor thermal comfort during winter and summer seasons under both current and future climates. This methodology is applied to an existing school built in 1990 in Jericho-Palestine, which has a hot desert climate. Classrooms rely on the thermal mass to increase the indoor temperature in the winter, and natural ventilation to reduce it in the summer. The effect of climate change on indoor thermal conditions is evaluated using typical warmer and colder future years based on the latest SSP5-8.5 scenario. The results showed that the calibrated and validated BSM achieved a highly accurate prediction of indoor air temperature compared to indoor air measured temperature. The validated BSM showed extreme cold for 880 h (91% of wintertime) and excessive heat for 90 h (19% of summertime) during school days. Passive winter measures, including high insulation and airtightness level, and using double glass windows, reduce undercooling to less than 40 h but increase overheating to 180 h. Passive summer measures, including night cooling and exterior shading, are necessary to reduce overheating to around 40 h. These measures are still effective in resisting the cold future years, but more creative passive summer measures and/or a mechanical cooling system are needed.

Simulation-based assessment of the climate change impact on future thermal energy load and indoor comfort of a light-weight ecological building across the six climates of Morocco

The potential effects of global climate change on buildings are a growing concern worldwide, as rising temperatures can significantly impact their energy performance and indoor thermal comfort conditions. This article examines the impact of global warming across six different climate zones of Morocco by comparing under 2050 RCP8.5 scenario the current and future thermal energy requirements and indoor comfort levels of a light-weight ecologically-designed detached residential house. The reference case study building is in a semi-arid climate of Morocco and empirically validated following the ASHRAE guideline 14, with CV(RMSE) less than 3.2 and NMBE less than 1.4 for the two 38-day monitored thermal zones.The study includes aframework to evaluate the thermal energy needs for maintaining indoor thermal comfort and the overheating intensity triggered by climate change and varying due to spatial scale. Overall, the findings show that Morocco will suffer with differing magnitudes from the temperature increase linked to global warming, which will result in an upsurge in the thermal needs for cooling, particularly in the southern regions of Morocco, and a general reduction in the heating thermal energy needs across the different climates of Morocco, with an annual thermal energy demand change ranging from −2.7% to 17%, depending on the investigated city. This wide variation in thermal energy demand underlines the need to assess the effects of the warming climate in the local context. Besides, under conditions of Air Conditioning (AC) failure, the Indoor Overheating Hours (IOH) increase up to 27% between the current climate conditions and the 2050 climate conditions while indoor temperature changes exceed 1.5 °C during the hottest days of the summer.Strategically, the research study intends to support global efforts to build resilient societies by bringing awareness to how susceptible indoor occupants are to projected warming temperatures. The study also lays the groundwork for prioritizing and assessing adaptation solutions to protect people's health, comfort, and productivity within buildings despite climate change in the most sustainable manner.

The effect of geometry and location of balconies on single-sided natural ventilation in high-rise buildings

The demand for housing and the expansion of urbanization have increased the price of land and vertical growth of buildings, resulting in converting the courtyard and porch to balconies. Nowadays, semi-open spaces, which play a critical role in providing optimal indoor air and thermal conditions, are neglected. In addition, the area of such spaces is regarded as limited and sometimes even the balcony is eliminated, leading to improper thermal behavior and increased energy consumption, while such elements can be used for better natural ventilation of spaces and utilization of natural energy, resulting in reducing energy consumption in addition to controlling the pressure created by the wind in the case of correct design. The purpose of the current paper is to evaluate the performance of balconies on the high-rise buildings using single-sided ventilation in the harsh hot-arid climate of Hamdan in Iran, which there has not been studied already A general basic model is presented according to field studies and criteria. Field survey indicates that most of the high-rise buildings in Hamedan have single-sided natural ventilation, as well as are located on the south side, have a rectangular shape, are enclosed on three sides, and have recessed balconies. Based on the climate data of Hamedan, July is considered the hottest month of the year, during which natural ventilation should be applied. Simulation is conducted by computational fluid dynamics (CFD) method and ANSYS software. Based on the results, 4.5 m width and 1.5 m depth are regarded as the best geometry of the balcony for Hamedan providing a mass flow rate up to 1.38 kg/s. In addition, the position of the balcony in the wall of the building should not be symmetrical. The usage of a balcony in the middle of the façade could provide higher ventilation rate and reduce cooling energy up to 7% compared with the base case. Through a meticulous balcony design, wind could path through the larger spaces then it is led towards the opposite window, and finally exits the building in a single-sided ventilation mode. This causes the air to flow in most of the interior spaces, leading to better ventilation than other methods.

Air-conditioning usage behaviour of the elderly in caring home during the extremely hot summer period: An evidence in Chongqing

Using air conditioners to cool down the indoor thermal environment is necessary to avoid the elderly exposing themselves to hot conditions in extreme weather. Considering the frequency occurrence of heatwave events, this study investigated air-conditioner operation behaviours and indoor thermal condition features during extremely hot summer periods to understand the elderly's thermal demand and their behaviour patterns of using air conditioners. Fifteen elderly residents from a caring home in Chongqing were recruited, and their air-conditioners’ historical operation data and indoor and outdoor temperatures were continuously measured and retrieved from the air-conditioner manufacturing data warehouse. The results indicate that the elderly subjects were active in adjusting their air-conditioner settings with multiple daily actions of turning-on and setpoint-changing behaviours in the extremely hot summer period. The air-conditioner temperature setpoint preferred by the elderly subjects was between 27 °C and 30 °C, resulting in the indoor temperature mainly remaining in the range between 28 °C and 32 °C, which presented a negative relationship with the outdoor temperature. The elderly's daily air-conditioner operation in the extremely hot summer period can be clustered into four groups, including inactive-usage, afternoon-usage, night-usage and all-day-usage groups. The inactive usage group with short-term and discrete air-conditioner operation would prefer a fast-cooling setting, whereas the all-day usage group showed a higher setpoint-change frequency, indicating the dynamic cooling demand may exist in the elderly's long-term air-conditioner daily usage.

Evaluating the Impact of Trees on Residential Thermal Conditions in Los Angeles Using Community Science

As the planet warms, heat-vulnerable communities in cities face increased heat-related risks including lost productivity, reduced learning outcomes, illness, and death. Despite the growing threat of heat, effective approaches to alleviate urban heat are available. Tree planting has received investment in a growing number of cities around the world, but there are significant gaps in our understanding of the cooling potential of trees in the urban context, particularly the impacts on indoor spaces where urban dwellers spend most of their time. Our study engaged community scientists in Los Angeles County, USA to collect data on the impacts of trees on indoor and outdoor thermal conditions in residential sites. Participants created a thermal sensor network that contributed continuous readings for the study period. We mimicked an experimental research design using a difference-in-differences approach where “treehouses” with more trees and “non-treehouses” with fewer trees were compared on hot days (>90°F or 32°C) and non-hot days. We found that on hot days indoor temperatures in treehouses warm less than in non-treehouses, but that trees provide relatively less benefit at night. We also found that exposure to extreme heat reaches dangerous levels in older residences without trees or air conditioning. underscoring the need for swift action to cool heat-vulnerable communities.

Evaluation of the cooling potential of a vertical greenery system coupled to a building through an experimentally validated transient model

Despite several studies showed that Vertical Greenery Systems (VGSs) have relevant thermal benefits at urban and building scales, researches devoted to investigate the benefits of a green facade through detailed transient thermal simulations are scarce. Furthermore, a study comparing the effectiveness of different plant types is still missing. The present paper aims to fill such gaps by studying the effectiveness of a green façade to improve the thermal behaviour of a well-insulated lightweight building in the Mediterranean area, as well as the perceived indoor thermal conditions, based on both on-site experimental measurements and dynamic thermal simulations with a novel Type in TRNSYS validated through the monitoring campaign. To this aim, two identical full-scale prefabricated modules were installed and monitored at the University Campus of Catania (Italy), differing from each other because one of them hosted a climbing plant species in its west façade. The validated numerical model was then used to appraise the cooling effect of the green façade with two different plant species commonly used in Mediterranean countries (Trachelospermum Jasminoides and Hedera Helix namely). Results show that Hedera helix ensures the best performance when the foliage layer is at an intermediate state of its growing process, while under full foliage development the species investigated show almost the same performance. The incoming heat flux can be strongly attenuated, showing a quite flat daily profile, while the peak value of the internal and external surface temperature of the wall can be reduced by up to 1.6 °C and 10.5 °C, respectively.

Analysis of Measured CO2 Levels through Long-Term Monitoring in Renovated Multifamily Buildings: A Common Case

The purpose of this study was to analyze the indoor air quality, in particular, the CO2 level, in a real environment, within 16 apartments located in the municipality of Zalău, Romania, in five recently renovated multifamily buildings in which families live under normal conditions. Long-term monitoring was undertaken for 4.5 months, during the heating season of 2022–2023. A representative microclimate perspective was analyzed: the median value of the time fraction, which exceeded the Indoor Environment Quality Category I (IEQcat I) threshold for adults’ bedrooms was 82.30%. For children’s bedrooms, it was 75.65%, while for living rooms, it was 58.78%. When considering IEQcat IV, it was identified that for the bedrooms, the time fraction for which the threshold values were exceeded was still significant (median value of 45.37% for adults’ bedrooms and 50.14% for children’s bedrooms). Even if the indoor thermal comfort conditions increased, it was found that for almost half of the time, the bedrooms did not provide a health-safe indoor environment for the occupants due to inadequate ventilation, exceeding the health threshold values. Thus, it was identified that the ventilation of buildings is a key issue within the renovation process and, currently, is not properly undertaken for the mass renovation of existing multifamily residential buildings.

Double Skin Façade Mechanical Systems as Ad-vanced Building Technologies

The double-wall façades (or “double skin façades”) are deter-mined as building mechanical and engineered systems realized by the cavity between the inner curtain and the outer screen, for thermal and acoustic insulation, for ventilation and for the inser-tion of functional devices (such as sunscreens) and, also, plant ducts. The cavity between the two enclosures constitutes a venti-lated cavity that can be used according to certain modes of func-tioning (passive or active type) aimed at controlling external cli-matic and environmental stresses in order to regulate the condi-tions of the interior spaces. The double envelope system is real-ized as an apparatus of mediation and reaction towards envi-ronmental loads, according to the needs of well-being and reduc-tion of energy consumption. In general, the system offers the functioning in the form of a passive solar system, assuming the use and accumulation of solar radiation for the regulation of indoor thermal comfort conditions, and the functioning for the capture and input of air flows. The calibration of solar radiation is integrated with the use of shading devices in order to achieve diffuse lighting conditions in interior spaces. In addition, the application of the double glass surface reduces thermal losses from the interior spaces by reducing the speed of the airflow in contact with the inner curtain, increasing thermal insulation. The system foresees that the ventilated cavity performs various inte-grated functions (for the definition of complex mechanisms of dynamic interaction with the external climatic conditions), both permanent (e.g. for the increase of thermal inertia and acoustic insulation relative to the internal curtain) and temporary (e.g. for the cooling of the same spaces during periods of high tempera-ture).

Impact of solar radiation on indoor thermal comfort near highly glazed façades in a hot-humid subtropical climate: An experimental evaluation

Solar radiation has a profound impact on indoor thermal conditions, particularly in highly glazed spaces. However, there have been limited field measurements on this subject. Focusing on subtropical climate, this study investigated the effects of irradiation on thermal comfort from two aspects, disparities in glass properties and spatial positions, through a field measurement. Six test cells, each equipped with a representative type of glass, were established; two measurement points were set at inner and near-window positions to analyze the spatial disparities and impacts of solar radiation asymmetry. PMV-PPD-based evaluation criteria were employed to assess the long-term comfort levels and classified by environmental quality index (EQI); additionally, we assessed the risk of overheating by considering two indices: overheating hours and overheating severity, which represent the duration and extent of thermal discomfort. The results indicated that radiation asymmetry varied depending on glass properties and spatial/temporal difference, leading to partial thermal discomfort. Specifically, the MRT at the near-window point increased significantly, reaching 50.8 °C for single-pane glass, 40.1 °C for single-pane tinted glass, and a minimum of 32.8 °C for double-pane reflective glass after 14:30 due to direct sunlight. In contrast, the MRT at the indoor positions remained relatively stable at around 25 °C–27 °C, irrespective of the glazing type. SHGC of glass is critical for thermal comfort, as higher SHGC values intensify the sensation of extreme warmth. Through experiments, this study quantified the relationship between thermal discomfort and glazing properties, providing valuable insights for glazing facades design that can optimize indoor thermal environments.

Investigation on Energy Use in Passive Design House at High Altitude Climate in Malang City, Indonesia

Indonesia is a tropical climate, hence building controlling air ventilation and humid condition have been a challenge to meet residents’ convenience. It is often energy usage that is majorly used to control indoor air climate circulation. The passive design has recently received increasing attention as an option to reduce energy consumption and abate carbon footprint by taking advantage of local climatic conditions of building features. This pilot study seeks to identify the relationships between real energy consumption data and building design data. A dwelling house located in Malang, Indonesia was selected as a sample building for the study which introduces a method to use real energy consumption data to calculate the extra energy use related to tropical indoor thermal conditions. The 24 h observation result was validated through interviews with residents, before analyzing with criteria of ideal climate conditions from the literature study. This study also presents relationships between the increase in mean daily energy consumption data and trends of humidity building design data. In conclusion, this present study establishes the starting point for exploring all features affecting the tropical climate benefits of passive design for building energy efficiency.