Near-optimal temperature setpoint transition strategies for peak load reduction and thermal comfort in grid-integrated school buildings

Space Design for Thermal Comfort and Energy Efficiency in Summer

Indoor thermal comfort is essential for occupants’ well-being, productivity, and efficiency. Global climate change is leading to extremely high temperatures and more intense solar radiation, especially in hot, humid areas. Passive cooling is considered to be one of the environmental design strategies by which to create indoor thermal comfort conditions and minimize buildings’ energy consumption. However, little evidence has been found regarding the effect of passive cooling on the thermal comfort of historical buildings in hot–dry or hot–humid areas. Therefore, we explored the passive cooling features (north-south orientation, natural ventilation, window shading, and light color painted walls) applied in historic residential buildings in Zanzibar and evaluated the residents’ thermal responses and comfort perception based on questionnaires and field surveys. The results showed that the average predicted mean votes (PMVs) were 1.23 and 0.85 for the two historical case study buildings; the average predicted percentages of dissatisfaction (PPD) were 37.35% and 20.56%, respectively. These results indicate that the thermal conditions were not within the acceptable range of ASHRAE Standard 55. Further techniques, such as the use of lime plaster, wash lime, and appropriate organization, are suggested for the improvement of indoor thermal comfort in historical buildings in Zanzibar. This study provides guidelines to assist architects in designing energy-efficient residential buildings, taking into account cultural heritage and thermal comfort in buildings.

Passive cooling in a low-energy office building

Natural ventilation potential (NVP) has been evaluated for two climate-specific Indian cities New Delhi and Jodhpur in terms of pressure difference Pascal hour (PDPH), under various indoor conditions. Indoor temperature, indoor heat gain, and natural ventilation rate because of both buoyancy and wind effect have been evaluated for a conceptualized low-rise building using an analytical model for NVP. Thermal comfort in these stations has been evaluated in terms of percentage of time the indoor temperature falls within the thermal comfort zone. Qualitative assessment of NVP has been carried out through the cumulative frequency curves for adequate pressure variation throughout the indoor and outdoor environment of the building. The thermal comfort assessment shows that New Delhi and Jodhpur have indoor thermal comfort for 40% of the time in a typical year. Thermal comfort is found to exist for 45–90% of the time during the months of July, August, and September, whereas least thermal comfort period of 20–40% is observed during winter months of December, January, and February and PDPH curves confirms the fact that natural ventilation alone does not provide indoor thermal comfort. To achieve thermal comfort in the building during the rest of the time, an active system or complex passive systems are required to be employed.

The UN has issued a policy regarding the achievement of sustainable development goals, among which are to ensure inclusive and equitable quality education and promote lifelong learning opportunities for all. One of the contributors to the quality of education is the convenience of buildings as educational facilities. This paper describes thermal comfort analysis in the case study of the LABTEK VII Building on the Bandung Institute of Technology campus divided into 2 cases: the open space in the building’s hallway and the study room in the building. Thermal comfort analysis uses standard thermal comfort analysis tools as a measurement effort. This research was conducted by analysing the indicators of thermal comfort in educational buildings with multiple capacities in temperature, humidity (humidity), and wind speed obtained from Meteoblue and indicators of metabolic rate and clothing of building users. The analysis of these indicators is processed using CBe thermal Comfort and Rayman to produce thermal comfort in the building. This paper presents the highest PET values obtained at 2 pm with PET temperatures reaching 40 ° C, considered a Hot sensation. And in the CBE measurement results, it can be seen that the process of changing indoor temperature from morning to evening is getting higher. From measurements with these two tools, concludes that the thermal comfort at Labtek VII ITB is thermally comfortable.

Thermal comfort in educational buildings: The Classroom-Comfort-Data method applied to schools in Bogotá, Colombia

Thermal comfort in the building affects occupants’ health, productivity, and electricity use. Predicting occupants’ thermal comfort in advance will be helpful. Nowadays, a widely used model for thermal comfort prediction is the predicted mean vote (PMV). However, studies have found discrepancies between PMV and thermal sensation votes. In this paper, a comparative study was made by developing thermal comfort prediction in office building models using linear estimation and machine learning (ML) algorithms. Fanger’s six parameters and nine other parameters are considered for linear estimation and ML input parameters. These parameters are divided into two groups: the psychology group with the parameter’s thermal preference, thermal acceptance, overall comfort, air movement vote, humidity preference, and humidity vote, and the personal group with the parameters of gender and age. The predictive model developed showed the validated coefficient of correlation of more than 0.88 for both categories. For ML, training and evaluation have been done for five ML models: Artificial Neural Network (ANN), Support Vector Machine (SVM), Random Forest (RF), Decision Tree (DT), and K-Nearest Neighbour (KNN). The findings showed that new parameters made significantly better thermal comfort prediction. RF has the lowest prediction average error, 0.706 when including all the psychological group parameters.

Optimum conditions help us think and work better. Thermal comfort in lecture buildings is important to maintain students’s comfort and help them concentrate on study. The fastest way to achieve expected thermal comfort inside the lecture room is using air conditioner, however, compensation on high electricity bills and degradation of the environmental quality has to be made. Therefore, the aim of this paper is to find and promote several environmental friendly strategies which can provide comfort to users in one hand, but also can reduce energy consumption in another hand. There have been several strategies in records to increase thermal comfort in buildings. To select the best and the most appropriate alternative, Analytical Hierarchy Process method was used by setting the criteria, sub-criteria, and alternatives to increase thermal comfort in lecture buildings of Andalas University. To test the selected alternative, thermal comfort inside two lecture rooms were evaluated experimentally. The comfort level was evaluated using PMV (Predicted Mean Vote) and PPD (Predicted Percentage Dissatisfied) model. For all experimental conditions, PMV and PPD results and individual thermal vote results showed a good match statistically meaning that the PMV and PPD models could predict thermal condition inside the lecture rooms. Results also showed that the presence of natural vegetation infront of glass windows of the lecture rooms statistically improved thermal comfort sensations of students under natural ventilation mode and reduced thermostat setting under air conditioning mode.

Thermal comfort and building energy consumption implications – A review

Improving students’ thermal comfort in university courtyards and indoor spaces promotes walkability, enhances livability, and fosters social interaction among students. This study aims to improve students’ outdoor thermal comfort in university courtyards, to reduce heat transfer to classrooms, and to accordingly reduce energy consumption in university buildings in hot arid climates. Thus, the proposed coupled methodology for the case study, the Faculty of Agriculture, New Sohag University, Egypt, consists of three stages. First, monitoring and questionnaire surveys were conducted in the open courtyard and the classroom to obtain air temperature, wind speed, thermal image, and CO2 and thermal comfort analysis. Secondly, the Envi-met model was used to investigate the impact of six improvement solutions on improving thermal comfort in the courtyard. Third, retrofitting strategies in the building envelope were evaluated to decrease heat transfer and energy consumption by DesignBuilder software. Consequently, the findings revealed a high outdoor air temperature, which causes discomfort for students. Hence, the simulation results concluded that the significant reduction of physiological equivalent temperature (PET), which ranged between 11.1 °C and 13.9 °C, occurred after applying the hybrid improvement solutions (vegetation area and semi-shading or pergola-shading). Moreover, integrating a combination of retrofitting strategies into the faculty buildings contributed to a 30% reduction in energy consumption. Ultimately, the proposed methodology aims to assist architects and urban designers in the early design stages by providing the appropriate environmental solutions for the universities’ courtyards and buildings in hot arid climates.

Heated glass can be applied to improve windows’ condensation resistance and indoor thermal comfort in buildings. Although this applied technology has advantages, there are still some concerns in practical applications, such as additional energy consumption and control issues. This study evaluates the effectiveness of a heated window heating (HWH) system in terms of thermal comfort and heating energy performance (HEP). The simulation-based analysis is performed to evaluate the effectiveness of the HWH using a residential building model and to compare it with radiant floor heating (RFH) and hybrid heating (HH) systems (i.e., combined HWH and RFH). This study also investigates the peak and cumulative heating loads using HWH systems with various scenarios of control methods and setpoint temperature. The predicted mean vote (PMV) is used as an indoor thermal comfort index. The ratio of cumulative thermal comfort time to the entire heating period is calculated. The results show that HWH and HH can reduce the heating load by up to 65.60% and 50.95%, respectively, compared to RFH. In addition, the times of thermal comfort can be increased by 12.55% and 6.98% with HWH and HH, respectively. However, considering the social practices of South Korea, HH is more suitable than HWH. Further investigations for HH show that a surface setpoint of 26 °C is proper, considering both heating demands and thermal comfort. In addition, the setpoint temperature should be determined considering HEP and the thermal comfort for HWH, and the optimal setpoint temperature was suggested under specific conditions.

Thermal comfort in buildings is essential for occupant well-being and energy efficiency, particularly in naturally ventilated environments where indoor conditions are closely influenced by outdoor climates. Current studies have not fully explored how thermal comfort varies across regions with similar climatic classifications but distinct geographic and cultural contexts. Addressing this gap, we analyzed and compared the adaptive thermal comfort responses in different naturally ventilated buildings located in temperate oceanic regions arising due to the high latitude in Europe and the elevated Himalayan region of Darjeeling, India. A mixed-methods approach was used with data from classrooms, offices, and residential buildings with adaptive thermal comfort modeling. The results show that European buildings exhibit narrower thermal comfort ranges compared to Darjeeling, for example, 21.2~24.8 °C versus 16.0~21.6 °C for 80% comfortability in classroom settings, respectively. Statistical analysis revealed significant differences in clothing insulation levels, with occupants in Darjeeling buildings demonstrating higher variability (mean rank 2103.31) compared to their European counterparts (mean rank 1207.30, p < 0.001). Additionally, a stronger correlation between indoor and outdoor air temperature was observed in Darjeeling (R: 0.785, p < 0.001), reflecting limited thermal buffering compared to European buildings (R: 0.372, p < 0.001). The paper advances adaptive thermal comfort models that account for regional differences and links these finding to sustainable building practices. The findings provide actionable insights for energy-efficient, climate-responsive building practices while supporting global sustainable development goals.

Impact of light-colored paint materials on discomfort in a building for hot-dry climate

The optimization of thermal comfort in buildings and passenger cabins has become one of the major aspects during the conception phase of HVAC systems. The static PMV model is among the most recognized thermal comfort models and depends besides the dry air temperature, radiant temperature, humidity and air velocity also on the activity level and the clothing of the human. The aim of this investigation is the application of a simple and reliable model of human metabolism based on Olesen combined with CFD simulations to attain a sufficiently accurate reflection of the human heat exchange to evaluate the PMV index and predict thermal comfort in a fast and cost-effective way by CFD simulations. Basis of the CFD model developed in the current investigations are measurement results obtained during experimental investigations inside a cabin mock-up model placed in a controlled climatic chamber under various pre-defined steady-state environmental conditions. The cabin mock-up model is equipped with a radial-flow fan for influencing convective flow inside the cabin and a temperature control system for adjusting the ceiling surface temperature to obtain mainly the impact of radiant temperature on the thermal comfort. Depending on the activity level, the local clothing and ambient conditions such as the flow structure inside the cabin, the local human heat flux due to convection and radiation is examined within a steady-state, two-way-coupled CFD simulation coupling human and environment with one continuous fluid phase (dry air) and the usage of the discrete transfer radiation model.

The dry Mediterranean climate (BShs) is the European region with the highest number of hours of sunshine per year. The high annual solar radiation makes sun shading devices necessary to comply with current energy efficiency standards. However, these standards do not sufficiently consider their effect on the indoor lighting comfort of buildings. The objective is to qualitatively and quantitatively determine how movable sun shading devices jointly influence the energy efficiency, thermal comfort and lighting comfort of buildings in BShs climate. The scientific novelty of the work consists of demonstrating the limitations of the sun shading systems commonly used in southeastern Spain and determining the optimal technical solution in this climate to simultaneously improve thermal and lighting comfort. This research comparatively studies the influence of various movable sun shading systems on the daylighting and thermal performance of an educational building. This study conducted on-site measurements, user surveys and computer simulations to study how to improve the thermal and lighting performances of the building. This work demonstrates that interior solar shading provides little improvement in thermal comfort and reduces the cooling demand by only 25%. External movable sun shading improves thermal comfort and reduces the cooling demand by more than 60%, but only adjustable blinds or awnings achieve adequate and homogeneous illuminance values as they diffuse daylight. The paper concludes that energy efficiency standards should be modified to ensure adequate lighting comfort in buildings.