PMV Values Research Articles

Review and Measure Winter Thermal Performance in CLT Building: A Case Study on Meldia Research Institute for Advanced Wood

Abstract CLT (Cross Laminated Timber) as a building material could help lower the carbon footprint of construction projects. Thermal performance and comfort in CLT buildings as a place to work are very important for optimizing comfort and work quality using CLT buildings. In winter conditions, measure and review is very necessary to optimize the desired building according to the standard level of comfort when working. The aims of this research is to measure and review indoor thermal comfort of CLT building during winter, with the case study Meldia Research Institute for Advanced Wood, Fukuoka, Kitakyushu. This research method involves measuring indoor temperature intensity in winter to understand how CLT buildings can achieve an optimal balance of thermal comfort. The results of measurements using PMV analysis of both rooms with the HVAC on at a temperature of 22 degrees Celsius are that the PMV value tends from a Slightly warm condition (+1) to a Neutral (0) at each measurement time and at all points. Room 1 has the highest PMV value between slightly cool (-0.5) to Slightly warm (+1), while room 2 has the lowest value between Cool (-2) to Slightly warm (+1). These findings can guide building designers in developing architectural solutions that are sustainable and focus on occupant well-being.

Construction of a Model for Assessing the Comfort of Residential Indoor Environment Based on Multisensory Design

Economic development and technological progress have made people’s demand for indoor environments higher and higher, and designing safe, comfortable, and healthy indoor environments through multisensory design is worthy of serious consideration. In order to realize the assessment of indoor environment comfort under multi-sensory design, this paper carries out data assessment from three dimensions of thermal environment, light environment and air environment. Relying on the PMV model of thermal environment comfort, we analyze the trends of indoor temperature and humidity, average radiant temperature, and PMV values. Combine Weber-Fechler and lighting coefficient to study the visual comfort change of indoor light environment, and analyze the lighting illuminance of indoor light environment under different working conditions by illuminance uniformity. From the basic principle of indoor wind environment, the changes of effective temperature difference and blowing sense caused by air temperature and wind speed are investigated. The temperature difference of the south-facing room decreased between 12.14% and 15.65% before and after the heating was stopped, which is a small change. The average indoor ambient radiant temperature values at different measurement points were up to 27.59 °C, and the fluctuations of the average indoor thermal ambient PMV values were within the range of [-1.2,1.6]. When the indoor light ambient illuminance value increased from 200 lux to 600 lux, the visual comfort improvement was more significant than from 600 lux to 1000 lux. The indoor air distribution characteristic ADPI value was 100% when the air velocity was 0.15m/s and 0.25m/s. Based on the results of indoor environment comfort assessment, multisensory optimization of indoor environment comfort from heat, light and air environments is proposed to provide guidance for improving people’s satisfaction with indoor environment.

Evaluation of insulation effectiveness for thermal comfort in summers: experimental and CFD numerical study

We evaluate the thermal performance of PUF-insulation boards embedded in the roof of an office-sized room. Two rooms were constructed: one with and the other without insulation. The thermal comfort was evaluated by performing an experimental study according to ANSI/ASHRAE Standard 55-2017. The inside air temperature, humidity, wall and ceiling temperatures, air velocities and thermal flux were measured for the summer April–June 2023. Using these measurements, the PMV and PPD values were computed. The effectiveness of the insulation material with regard to thermal comfort is judged by the reduction in values of these indices. During a typical day, a reduction of around 30% is achieved just by adding the insulation. Nusselt number correlations are proposed to predict the convective heat transfer from the walls. Detailed CFD simulations were performed and a parametric study to understand the effect of insulation thickness, wall insulation, roof thickness and room dimensions on thermal comfort was undertaken.

Optimization Strategy for Thermal Comfort in Railway Stations above Ground Level in Beijing

Urban rail transit, a convenient and fast public transportation mode with rapid construction and development, occupies fewer land resources and accommodates large passenger volumes. However, thermal comfort should be given more attention. Stations above ground level experience poor thermal comfort on the platforms, especially in hot summers. This study combines field research with a simulation analysis to propose a strategy for improving thermal comfort on above-ground urban rail transit platforms. This study analyzed the effects of the skylight opening rate, side window opening rate, design of transparent maintenance structure shading, and the platform profile shape on the thermal comfort of above-ground stations using field research, comparative experiments, and a simulation analysis with the PHOENICS (Command Prompt) software. The results indicate that adding longitudinal sunshade louvers to the skylight of the station platform is a cost-effective method to reduce the average temperature and PMV value, thereby improving thermal comfort. Increasing the skylight opening rate can result in a temperature rise. Adjusting the opening rate of the side windows to 20% and adding sun-shading louvers can also significantly enhance the station’s thermal comfort. Taking Wudaokou Station on Beijing Line 13 as an example, the simultaneous installation of additional longitudinal skylight shading and side window shading and increasing the side window opening rate to 20% on the platform resulted in a 2.6 °C decrease in the average temperature, a 4.7% increase in the average wind speed, and a 0.62 decrease in the PMV value, significantly enhancing thermal comfort for passengers. This study confirms that optimizing shading and ventilation systems can significantly reduce the platform temperature and improve passengers’ thermal comfort. This study provides theoretical support and innovative methods for optimizing thermal environments in similar environments.

Optimizing human thermal comfort and mitigating the urban heat island effect on public open spaces in Rome, Italy through sustainable design strategies

The climate affects how a city’s outdoor spaces are utilized. It is more likely that people will use and appreciate public areas designed for pedestrian use, such as parks, squares, streets, and foot-cycle pathways, when they provide a comfortable and healthy environment. A predicted increase in global temperature has made the climate uncomfortable, especially during the summer when heat stress is strengthened and anticipated. This phenomenon is more severe in urban areas, often affected by the Urban Heat Island (UHI) effect. Since the spatial characteristics of a city influence its climate, urban design can be deployed to mitigate the combined effects of climate change and UHI. This research is conducted to study the UHI effect on thermal comfort in an urban open space in Rome (Italy) and aims at identifying and implementing a methodology that urban designers can follow to reduce the impact of urban heat islands and increase thermal comfort in urban outdoor space. This study is based on an urban design concept adopting the Sustainable Development Goals as guidelines; it investigates how UHI’s effect affects the use of public space and examines the influence of urban microclimatic conditions on the thermal perception of users through PET, PMV and PPD values, that were assessed through simulations with ENVI-MET software. The study thus proposes a redesign for the site in Rome, with a masterplan based on sustainable design principles, aimed at improving the microclimatic conditions in the site. The design solution was then validated through ex post simulations.

Optimization Design Methods for Thermal Environment Problems in Chinese University Teaching Buildings at Various Periods

Chinese universities have gone through three periods of centralized construction and significant differences in the design of teaching buildings in different periods may cause various thermal environment problems. This study takes a city in a cold region in northern China as an example and selects three teaching buildings built during three concentrated construction periods: 1950s to 1960s, 1980s to 1990s, and early 21st century as common cases. Based on field research, thermal environment measurement, APMV and PMV-PPD evaluation, and DeST simulation methods, it was found that the average summer APMV of the three teaching buildings was 1.37, indicating poor thermal comfort. In winter, the ambient temperature of the classrooms was below 18 °C for about 30% to 40% of the whole year, the average PMV value was −2.36, and the PPD value was obtained as 83.28%, far exceeding the standard requirements. The obtained results form a design strategy to optimize the thermal environment of teaching buildings. By considering the teaching building of historical architecture from the 1950s to 1960s as an example, the optimization design was carried out from three aspects to improve the indoor thermal environment and reduce the building’s cooling and heating load. The cumulative load of the building throughout the year was reduced by 21%, the cumulative heat load was reduced by 28.3%, and the cumulative cooling load was reduced by 10.1%. This research is anticipated to be of great reference significance for enhancing the thermal comfort of existing buildings, promoting energy conservation, and reducing carbon emissions. At the same time, it contributes to the protection and optimal use of historical buildings.

Summer and winter performance evaluation of double layered PTFE dome with aerogel-glass wool thermal insulation- field experiments and numerical simulation

Achieving optimal thermal performance in large membrane-enclosed buildings presents a significant challenge. Aerogel mats offer potential for enhanced insulation, but their effectiveness in varying seasonal conditions is yet to be fully determined. The current study investigates the thermal performance of an enclosed dome with double-layered PTFE membrane roof integrated with aerogel-glass wool insulation mats. This research utilizes field experiments to assess indoor thermal comfort and numerical model to evaluate the effectiveness of the dome’s insulation capabilities during summer and winter conditions. The Aerogel integrated areas show a difference of 10.26/3.72 °C for summer/winter while that of 9.36/3.22 °C for glass wool-integrated areas. An online thermal comfort tool utilized maximum indoor temperature values during both seasons obtained from numerical results indicating that winter comfort falls within ASHRAE comfort range with PMV value −0.48 but summer conditions require enhancements. Additionally, the study assessed the insulation’s effectiveness using Maximum Reduction in Temperature (MRT), Decay Factor (DF), and Time Delay (TD) indicators. Results showed significant thermal lag, with peak temperature delays of up to 3.1 h in summer and 2.2 h in winter. Notable temperature differences between the dome’s inner and outer surfaces, alongside 28 % and 27 % DF reductions during summer and winter, respectively, demonstrated the roof insulation’s effectiveness. These findings support the use of both experimental and numerical methods to develop thermal management practices that improve sustainable building design, emphasizing occupant comfort and energy efficiency.

Evolution the Relationship Between Physiologically Equivalent Temperature and Some Meteorological Parameters for Basra City, Iraq

Background: Physiologically equivalent temperatures (PET) is highly efficient in evaluating the thermal component of any given microclimate as a single thermal index. The assist stakeholders in understanding and interpreting existing bioclimatic, allowing them to make any required modifications and become more robust to predicted climate change. Objective: This study assesses the relationship between Physiologically equivalent temperatures (PET) and some Meteorological Parameters. Methods: The data for this study includes observed mean monthly air temperature values, relative humidity, and wind speed for the period (2001-2020). The data was acquired from “Iraqi Meteorological Organization and Seismology (IMOS)” stations for Basra city. The radiation and Human Bioclimatic (RayMan) model were used to simulate bioclimatic indices (SET, UTCI, PET, PMV). Results: The findings revealed that the greatest mean values for PMV (4.3), SET (36.3), PET (45.5), and UTCI (42.1) were seen in July and August. The measurements have a nice thermal sensation of PMV (-0.5 - 1.9), SET (19.2- 29), PET (18.1- 31.8), and UTCI (15.9 - 28.7) is most noticeable in the months of (March, April, and October). The results showed the PET values (cool) and (Slightly cool) between (9- 18.3) for January, February, March, and December. The value of UTCI was between (5.9- 8.5) within classes (Slight cold stress), the values of PMV (-2.6- (-2.1)) within classes (strong cold stress) and (Slight cold stress) and the value of SET was (10.2- 12.4) within classes (Slight cold stress). Conclusions: Correlations between PET and air temperature (0.99), indicating good agreement between PET and air temperature, and relative humidity (0.96). PET and wind speed (R2=0.56). The scattering pattern of PET and other thermal indices shows that all indexes have a significant correlation coefficient, between PET and UTCI (R2=0.99), between PET and SET (R2=0.98), and (R2=0.99) between PET and PMV.

Investigating enhanced thermal comfort and energy efficiency through strategized airflow in Micro-Zonal Occupant-Centric Control (MZOCC)

The potential of Micro-Zonal Occupant Centric Control (MZOCC) to save HVAC energy consumption in medium sized open-plan offices has been established in literature. This is done by virtually dividing a thermal zone into micro-zones and allowing independent diffuser-level control in each micro-zone when the micro-zone is occupied. In continuation, there is a need to ensure that thermal comfort is achieved within micro-zones under such localised control. This is important because several forms of discomfort such as draft, horizontal thermal asymmetry and vertical thermal gradients may arise in MZOCC. Further, the effect of MZOCC airflow control strategies, such as setback flow and setback temperature, which were proposed in previous studies on thermal comfort of occupants needs to be evaluated. In an attempt to address these research gaps, this study explores thermal comfort for different scenarios of diffuser arrangements, airflow control strategies and occupancy conditions and also explores the effect of varying supply velocities used in setback flow and setpoint temperatures used as setback temperatures on air distribution and thermal comfort.Results show that low PMV values, increased draft discomfort and heavy thermal gradients are observed for certain scenarios of MZOCC. Tuning airflow control by choosing appropriate setback flow or setback temperature helps in restoring thermal comfort. As different forms of discomfort are observed in different cases, it is important to plan micro-zones and control airflow, such that, MZOCC does not violate thermal comfort criteria while optimising energy efficiency. This study gives a framework for selecting appropriate airflow control strategies for a selected diffuser arrangement for a given occupancy condition. Comfort-based MZOCC that uses appropriate airflow control strategy saves about 60% energy when the zone is half occupied and about 85% energy when the zone is quarter occupied. Results also show that, improving the diffuser arrangement improves energy savings and increases the options of airflow control strategies that can be used. Also, different airflow control strategies behave differently for each diffuser arrangement and has to be chosen separately for given diffuser setting and occupancy condition.

Numerical-experimental investigation of a wind tower-room sustainable system: A parametric analysis of the mixed convection with humidification

The wind tower is a sustainable architectural solution designed to improve natural ventilation and thermal comfort in buildings while reducing energy consumption. This study examines thermal comfort, natural ventilation, and heat transfer in a wind tower-room system with air humidification, such that the interaction of mixed convection with these parameters can be linked. The performance of the system is evaluated considering both natural and forced convection, influenced by differential heating and air inlet through the tower, respectively. A parametric analysis explores various parameters like outside air temperature, humidity, and velocity, along with room wall temperatures. Reynolds and Grashof numbers range from 8.57 × 103-1.99 × 105 and 2.20 × 109-1.31 × 1010, respectively. Simulations are validated against experimental data, with deviations under 5.0 %, 10.0 %, and 19.6 % for dry-bulb temperature, wet-bulb temperature, and air velocity. The system shows improved heat extraction efficiency under dominant forced convection conditions. Humidification yields PPD values between 10.0 % and 46.0 % and PMV values below 0 at air temperatures range 25.0–30.0 °C. At air temperatures of 35.0 °C with air humidity below 40.0 %, PPD values remain below 20.0 %. However, above 40 % humidity, humidification is less effective. The air exchange effectiveness reduction due to humidification is minimal at 0.61 %. These results illustrate the combination of parameters necessary for the optimal performance of the tower-room system, this study provides a valuable guide for integrating wind towers with humidification systems in building design and contributing to reduced electricity use and CO2 emissions.

Thermal performance of a novel traditional Chinese personal heating device (Huotong) combined with PCMs

Chinese traditional individual heating equipment with a history of hundreds of years “Huotong” was widely used in rural areas. The Huotong consisted of a closed wooden barrel-shaped outer wall and an iron basin with combustion layer. However, the traditional Huotong had problems of low energy utilization efficiency and poor thermal comfort. Thus, a novel Huotong combined with phase change materials (PCMs) was proposed. The basic model of novel Huotong was designed and manufactured. The thermal performances of the novel Huotong under two kinds of heat sources of charcoal heating and electric heating were investigated. The results showed that: (1) Under the method of charcoal heating, the heat storage and thermal comfort performance of the novel Huotong were higher than that of the traditional Huotong. Under the three-charcoal mass of 0.15, 0.25 and 0.5 kg, the heat storage performance of the novel Huotong was 1.36, 1.43 and 1.52 times of the traditional Huotong, respectively. The average PMV values of the novel Huotong was 0.92, 1.17 and 1.31, while for the traditional Huotong was 0.87, 1.32 and 1.58, respectively. (2) Under the four electric heating methods, the thermal efficiency of the novel Huotong was 1.63, 1.61, 1.47 and 1.39 times of the traditional Huotong, respectively. The heat storage performance was 1.72, 1.67, 1.47 and 1.28 times than that of the traditional Huotong. The average PMV values of the novel Huotong was 1.25, 1.22, 0.69 and 1.68, while for the traditional Huotong was 1.64, 1.53, 0.87 and 2.03, respectively.

Evaluation of Nature-Based Solutions to Improve the Urban Microclimate in Mediterranean Climate Conditions: A Case Study of Izmir-Karsıyaka

Today, rapid urbanization and increasing human activities have affected the climate at macro and micro scales in cities and caused unfavorable conditions in terms of human thermal comfort, especially in outdoor spaces. In this context, new solutions need to be researched, developed, tested, and updated to improve thermal comfort in cities. Using ENVI-met 5.1 software, this study investigated the effects of different NBS combinations on the urban microclimate and human bioclimatic comfort in Izmir (Turkey). The current situation, the scenarios where some nature-based solutions (NBS) are applied within the scope of the European Union’s HORIZON 2020 “URBAN GreenUP” project, and two other scenarios planned within the scope of the study were evaluated. The findings of the study showed that both the NBS scenarios created within the scope of the EU project and the NBS scenarios with large deciduous trees had the most positive impacts on improving thermal comfort conditions in all three study zones and achieved temperature reductions of up to 2.5 °C in urban temperatures. In terms of thermal comfort, the most significant differences were calculated between the minimum PMV values and were close to 1 °C. In addition, the simulation results showed positive changes in psychological stress levels.

Thermal Comfort in a Tropical Climate: Case Study of the Cafeteria in Student Residential College, UTHM Pagoh Branch Campus

Thermal comfort is important for buildings, especially in tropical climates. The issue of increasing indoor temperature is influenced by various factors that cause occupants to face thermal discomfort in cafeterias that uses both mechanical and natural ventilation systems. This study aims to determine the perception of occupants and evaluate parameter variations of thermal comfort in the cafeteria of Pagoh Campus Residential College, UTHM Pagoh Branch Campus. This study was conducted through the measurements of subjective and physical parameters. Data collection is carried out in two days, which are weekdays and weekends. This study uses some parameters variation which are thermal sensation vote index (TSV), predicted mean vote index (PMV), predicted percentage of dissatisfaction (PPD), operative temperature (To) and neutral operative temperature (Tneutop) to determine the thermal comfort conditions in the cafeteria. The results shows that the average values of air temperature, mean radiation temperature, relative humidity and air velocity from environmental measurements were 30.2 °C, 30.6 °C, 66% and 0.1 m/s respectively. In addition, PMV and PPD values were 2.0 and 76% from environmental measurements, while 1.36 and 43% from questionnaires. For To and Tneutop, the average values obtained are 30.4 °C and 28.6 °C. Furthermore, the findings showed that only the morning session was in the acceptable operative temperature range and complied with ASHRAE Standard 55 for both the 80% and 90% acceptability limits. At the end of the study, it was found that the values from the thermal environment measurements and surveys exceeded those recommended by ASHRAE Standard 55. This concluded that the quality of the occupants’ environment in the cafeteria is outside the satisfactory thermal comfort level. Therefore, the improvement through mechanical ventilation may very helpful in improving a good ventilation system as well as encouraging an increase in thermal comfort in the building.

A study on the impact of electrochromic glazing on indoor environment

The study investigates the impact of electrochromic glazing on indoor environments, providing valuable insights for the practical application of electrochromic glazing. Three rooms were constructed in Zhangjiakou City, China, equipped with different shading devices (electrochromic glazing, venetian blind, and base case of the glazing with no shading). Through experiments and simulations, the analysis of the overall indoor illuminance revealed that electrochromic glass, in its dark state, effectively reduces the average indoor illuminance while ensuring a uniform distribution of illuminance throughout the space, meeting the specified values for the discomfort glare index most of the time. During nighttime lighting, the average illuminance in room with electrochromic glazing was 42% higher than in the control rooms. In winter, the daily heat supply quantity in room with electrochromic glazing was 4.4%–21.9% higher than in the control rooms. In summer, the heat gain in room with electrochromic glazing was 19.1%–41.8% lower than in room with base case of the glazing. On a sunny day in winter, the room with electrochromic glazing exhibited more stable PMV values compared to the room with base case of the glazing, with a 20% increase in the duration of PMV thermal comfort compliance, but its Percentage of PPD values were inferior to the room with base case of the glazing. In summer, the room with electrochromic glazing outperformed both the room with venetian blind and the room wtih base case of the glazing in terms of PMV and PPD values.

An investigation concerning optimal design of confluent jets ventilation with variable air volume

This parametric study aims to predict the performance of confluent jets ventilation (CJV) with variable air volume (VAV) from four CJV design parameters. A combination of computational fluid dynamics (CFD), and response surface method (RSM) has been used to predict the energy efficiency, thermal comfort and IAQ for the four expected vital design variables, i.e., heat load (XH), number of nozzles (XN), airflow rate (XQ) and supply temperature (XTS). The RSM was used to generate a quadratic equation for the response variables exhaust temperature (TE), supply temperature (TP), PMV, DR, εT and ACE. The RSM shows that the TE, TP and PMV were independent of the number of nozzles. The proposed equations were used to generate setpoints optimized for thermal comfort (PMV) for summer, spring and winter cases with different CLO factors and different TS under a scenario where the heat load varied between 10-30 W/m2. TE was used as setpoint to regulate the airflow rate to keep the PMV values close to zero. The results show that by adapting the TS to the CLO factor both thermal comfort and the energy efficiency can be improved. Further energy reduction can be gained by downregulating the airflow rate to keep the TP at a fixed setpoint when the heat load is decreased. This means that a CJV can effectively be combined with VAV to improve environmental performance with good thermal comfort (-0.5 < PMV < 0.5, DR < 20%), above average IAQ (ACE ≈ 106%) and with a higher heat removal efficiency (ε T ≈110%) than conventional mixing ventilation.

Enhancement of Indoor Thermal Comfort Using Alternative Building Materials and Construction Technology in Low Income Housing - A Case of Trivandrum, Kerala

In India, rapid urbanisation followed by increased demand for housing has led to higher energy consumption in the building sector and a larger percentage of which is contributed by the housing sector. And the population using affordable housing is higher compared to other developed countries (MOUHA, 2013). The occupants tend to achieve the desired level of thermal comfort by personal adjustments and mechanical means. Using energy intensive methods for comfort is not feasible for a country, like India, with a low energy economy. This study analyses the indoor thermal comfort in low income housing with respect to the building materials and construction technology used. Two typologies of housing were studied which includes a row housing constructed using conventional materials, with hollow brick cement plastered walls and RCC roof slabs, and a vertical stacking multi dwelling constructed using Laurie Baker’s alternative construction technology, with rat-trap bond brick walls and filler slabs. The study explored the current scenario of housing based on a thermal comfort field study using questionnaire survey and onsite measurements (following ASHRAE class II protocol) which was then simulated using Design Builder software changing the wall material used to understand the improvement in indoor thermal comfort. An adaptive thermal comfort model and neutral temperature was generated for both types of housing which was then compared with IMAC Model ranges. The adaptive comfort ranges obtained for both housing were too warm than the acceptable ranges and the PMV values in row housing are hot, while that in vertical stacking is slightly warm to warm. The neutral temperature obtained in vertical stacking housing (28 deg C) is within the acceptable range, whereas that of row housing (28.8 deg C) is greater than the upper limit range of neutral temperature under the IMAC model. The results showed that building material with good thermal performance can cause a significant reduction in indoor temperatures thus improving indoor thermal comfort. Thus indoor thermal comfort in low income housing can be improved by using alternative construction technology, without compromising cost-effectiveness and affordability, and thus contributing to energy efficiency.

Design recommendations for the rehabilitation of an urban canyon in a subtropical climate region using aerial thermography and simulation tools

Outdoor public space is the setting for everyday social interaction where activities take place in order to satisfy collective urban needs. It is important to achieve climate-friendly urban design in order to ensure acceptable urban thermal comfort, especially in over-urbanised city centres during summer periods. In this research, an urban canyon street located in the historical centre of the subtropical city of Huelva (Spain) was analysed. After a survey carried out by in situ meteorological sensors and airborne infrared sensors (equipped on an unmanned aerial vehicle, UAV), the current thermal comfort was analysed in terms of PMV and PPD at different times of a typical summer day (11:00 h, 15:00 h and 19:00 h) with the aim of formulating design recommendations to improve its performance in terms of urban comfort. Then, thermal comfort was evaluated in different scenarios where feasible mitigation strategies (replacement of materiality, addition of vegetation and sun shading elements) were applied to classify them according to their effectiveness using the ENVI-met simulation tool. The results of the current scenario showed that, due to its N-S orientation and its aspect ratio (H/W), the urban comfort depends drastically on the day hour variation. A comfortable thermal environment is achieved at all points of the urban canyon as a result of the shade generated by the buildings during the morning and afternoon. However, in the central hours of the day the feeling of thermal discomfort was alarming (PMV values of +3 and PPD values above 90%). The proposed mitigation measures showed a considerable improvement in urban thermal comfort, with the addition of vegetation being the most effective solution (with an improvement in PMV value of 42% and a reduction in PPD value of 43%). The combination of all the proposed measures in a single scenario showed encouraging results in the rehabilitation of public spaces in use.

Assessment of some Bioclimatic Indices using RayMan Model for Baghdad-Iraq

Abstract The evaluation of bioclimatic conditions on a local scale is still an important topic. It might be a key component of the national plan for the sustainable development of various areas under changing climatic conditions. The present study aimed to examine the behaviour of four bioclimatic indices namely physiologically equivalent temperature (PET), Standard Effective Temperature (SET*), Universal thermal climate index(UTCI) and, Predictive mean vote(Pmv) derived from energy budget models for Baghdad city. The monthly means data of air temperature, relative humidity, wind speed, and solar radiation during the period (1981-2021) were used in this study. All calculations of this study were extracted using RayMan Model. The relationship between PET, Pmv, SET, and UTCI indices in addition to meteorological parameters was also conducted in this study. The results indicate that July and August had the highest values of Pmv (4), SET* (39.4), PET (43.9), and UTCI (39.4). For the majority of the studied indices, the comfortable thermal perception occurred only in March, April, and October. PET and UTCI revealed acceptable comparability in terms of temperature perception when compared to other indices for most months of the year. The maximum heat stress was reported for all indices between May and September, with the lowest stress occurring between January and December. April was the most comfortable month of the year, according to the data. Correlations between UTCI and meteorological parameters found a substantial association with air temperature (0.99) and relative humidity (0.98), respectively. The lowest correlation coefficient (R2=0.69) was found with wind speed. All other indicators indicate a substantial association with the UTCI.

An Anti-Condensation Radiant Heating Floor System in Buildings under Moistening Weather

In most regions of southern China, condensation frequently occurs on building surfaces during the period from March to April. This phenomenon has been affecting people’s safety and structural properties. This article proposes an innovative anti-condensation floor system based on the reverse Carnot cycle. The evaporation side treats the air and reduces the moisture content, and the heat extracted from the condensation side is recovered by a heat exchanger and transferred to the floor through capillary mats. Simulation studies of the dynamic operation performance have been conducted through the TRNSYS 18 software. The results show that an innovative anti-condensation floor system can effectively keep the floor dry in Guilin. At the same time, regarding the indoor comfort level index, the PMV value is within ±0.5, and the energy consumption of the system is 42% less than that of the cooling dehumidification system. The system also performs well in representative cities where the air moisture content is less than 12 g/kg. This article also provides a reference for the feasibility of radiant floor systems in humid climate areas.

Window Direction Factor toward PMV and PPD Values in Classrooms

Thermal comfort is an important element in students’ learning activities. The object chosen was the classroom of the Sawah Besar 01 Public Elementary School in Semarang, Indonesia built in a densely populated area, resulting in a window design that has varying orientation directions but with a homogenous façade design. This affects the level of thermal comfort in the classroom. Data analysis was carried out quantitatively – namely, to obtain a thermal comfort index, PMV, and PPD according to the Indonesia National Standard and ASHRAE. The thermal comfort conditions of all selected rooms on the 1st and 2nd floors, either indoor or outdoor, did not meet the comfortable thermal comfort standard for classrooms. The PMV index is above +1 and is mostly categorized as slightly warm, warm, and hot, and all of the PPD percentages are above 10%, indicating that most of the occupants are not satisfied with the temperature in the classroom. New façade opening designs and mechanical ventilation aids need to be applied to improve thermal comfort according to the Indonesia National Standard and ASHRAE.