Indoor Comfort Level Research Articles

Assessing Thermal Comfort in Studio Classrooms of an Institutional Building: Case of Composite Climate

Architectural studios represent unique indoor environments where the interplay of design, occupancy, and climate can significantly influence thermal comfort. This research article investigates the thermal comfort conditions in studio classrooms located within an institutional building in Lucknow, situated in composite climate. Lucknow subtropical climate, characterized by hot summers and mild winters, poses distinct challenges for maintaining comfortable indoor conditions. A study on the indoor comfort level of a studio space, where both theory and drawing classes take place, was conducted to assess their thermal conditions during student lesson hours. The study was conducted over two distinct periods, in January and May of 2024, to cover two different seasons. Six studio classrooms distributed across three floors were systematically assessed to comprehensively evaluate thermal comfort parameters. The field study involved monitoring thermal comfort during a hot summer week and a cold winter week, each consisting of 3 working days from 8 am to 4 pm. Through a combination of quantitative measurements and qualitative observations, various factors influencing thermal comfort, such as temperature and occupant satisfaction, were analyzed. The findings of this study contribute to a deeper understanding of thermal comfort dynamics within studio classrooms in composite climates, offering insights that can inform building design and management strategies to enhance occupants comfort and well-being. . KEYWORDS :Levels, Orientation, Temperature, Thermal Comfort, Thermal Environment

Flexible regulation of airport air-conditioning systems: Impact of cooling load variations on temperature stability

The integration of renewable energy sources has led to notable supply-demand imbalances due to their intermittent nature. Air-conditioning systems, as significant energy consumers with considerable flexibility, play a crucial role in integrating renewable energy and regulating power systems. This paper delves into the capability of air-conditioning systems in airports to flexibly adjust, particularly examining how varying cooling loads impact indoor temperatures. The energy flexibility of the air-conditioning system is evaluated based on three fundamental cooling load variations (incremental, translational, and discrete), and several evaluation parameters are defined. For areas with smaller cooling load fluctuations, there is a greater adjustment margin, but long adjustment periods should be avoided. For areas with larger fluctuations, the original cooling load curve should be considered in the adjustment strategy. The simulation results show that advancing or delaying the supply by 1 h during peak cooling load periods can ensure indoor temperature stability, and step-type cooling load curves do not adversely affect indoor comfort levels. Practical case studies further demonstrate that utilizing water storage as an active regulation strategy can reduce operational costs by 26 %, and with flexible adjustments, this reduction can increase to 35–54 %. The study offers a framework to optimize air-conditioning flexibility in airports, facilitating better renewable energy integration and grid stability, which holds significant potential to reduce costs and improve energy efficiency, thus contributing to sustainable energy management.

The Influence of Daylight Availability on Thermal Comfort in Classroom Environments

Daylight is not just an illuminating source for building interiors, but it is also a force that influences thermal comfort. Despite extensive research on daylight and thermal comfort, there remains a significant gap in understanding how these factors affect human behaviour. This study aims to understand how daylight influences not only aesthetic and energy-saving purposes but also individuals' thermal perception and comfort goes beyond, holding critical significance for design and planning decisions that shape modern living spaces. This study investigates the impact of daylight on thermal comfort in a classroom environment by collecting thermal responses through observations and measurements. Limitations of the study include a small sample size and the use of mobile phones to measure indoor air quality and comfort levels. Behavioural responses to daylight levels measured through a mobile application were observed, revealing that the impact of daylight on thermal comfort is not entirely independent but shaped by participants' perceptions and behaviours. Future research should increase the reliability and validity of findings by using larger sample sizes and specialized measurement tools.

Optimizing HVAC Systems for Pharmaceutical Manufacturing Facilities

This text provides an extensive overview of Heating, Ventilation, and Air Conditioning (HVAC) systems, their components, functions, and impact on energy consumption and building sustainability. It highlights the significance of HVAC systems in maintaining indoor comfort levels and discusses various techniques for enhancing energy efficiency. Additionally, it covers topics such as air handling units (AHUs), temperature and relative humidity testing, energy efficiency regulations, ventilation systems, air conditioning methods, and the effects of building behavior on HVAC energy consumption. The abstract also outlines advantages and disadvantages of HVAC systems, emphasizing their role in indoor air quality, energy savings, and environmental impact.

Variability in Heating Demand Predictions: A Comparative Study of PHPP and Mc001-2022 in Existing Residential Buildings

The construction industry is a key driver of environmental change due to its extensive use of resources and high emissions, thus significantly burdening global efforts towards sustainable development targets. A large portion of the environmental footprint of buildings results from the energy required to sustain indoor comfort levels. Thus, enhancing the energy efficiency of existing buildings becomes critical in reducing their environmental impact. This study explores the impact of thermal performance improvements on the heating demand, employing numerical modeling and two energy performance methodologies, PHPP and Mc001-2022, across various climatic datasets and case studies in Romania. The results show substantial variability in heating demand predictions: Mc001-2022 predicts up to 27.2% higher continuous heating demands and 21.0% higher intermittent demands compared to PHPP in one case study. In the second case study, the differences range from 8.1% higher to 6.9% lower for continuous heating and from 3.3% higher to 9.9% lower for intermittent heating, depending on the scenario. These findings underscore the importance of the methodological choice and localized climatic data in heating demand assessments, highlighting the need for a tailored, context-specific approach to energy performance assessment, integrating multiple energy efficiency measures suited to the unique characteristics of each building.

Assessment of Gel-Based Thermochromic Glazing for Energy Efficiency in Architectural Applications.

With the increasing global focus on energy efficiency and environmental sustainability, intelligent building materials such as thermochromic glazing have emerged as a hot topic of research. The intent of this paper is to explore the utilization of gel-type thermochromic glazing within the realm of architectural energy conservation calculations. It conducts an exhaustive examination of the material's attributes, its capacity for energy savings, and the obstacles encountered in real-world applications. Through simulation studies and case analyses, this paper assesses the energy efficiency of gel-type thermochromic glazing across various climates and suggests strategies for optimization. The study revealed that the incorporation of gel-based thermochromic glazing leads to a marked reduction in energy usage within buildings, an improvement in indoor comfort levels, and significant environmental advantages.

Winter indoor thermal environment and livability analysis of traditional residential houses in northeast Sichuan, China

With the rapid development of the national economy, increasing attention has been given to the living environment in rural areas, especially indoor thermal and wind environments. This study conducted on-site measurements and questionnaire surveys during winter in the indoor environment of five villages in northeastern Sichuan. Eighty-nine traditional residences were selected to investigate their fundamental characteristics, indoor thermal environment, humidity conditions, and comfort levels. Questionnaires and comparative experiments were also conducted with natives and locals. This combination of objective data and subjective feedback provides a comprehensive perspective for assessing the indoor thermal environment. The results showed that when expressed as neutral temperature and humidity, the temperature difference was 2.36 °C, with little humidity difference. Residents exhibited higher tolerance towards the local thermal and humidity environment than nonlocal volunteers, who showed greater sensitivity to it. In addition, residents had a Predicted Mean Vote (PMV) value of −0.69 and a heat acceptance value of −1.78, while non-local volunteers had a PMV value of −0.76 and a heat acceptance value of −1.32. A detailed evaluation and analysis of the relationship between the indoor thermal environment and human comfort of local residential houses was carried out, providing technical guidance for energy conservation and thermal insulation of local buildings.

Thermal Comfort Assessment of UPM Engineering Library in Tropical Climate Conditions

Thermal comfort is the study of indoor comfort level feel by the occupant in a room. This paper presents the study of thermal comfort that had been carried out in the library of engineering faculty at Universiti Putra Malayia in Serdang, Malaysia. The study was made in 4 days from 9 am to 11 am on October and November. This study was carried out to assess their thermal conditions during the occupants’ study hours. Thermal comfort variables were measured during study hours too. Qualitative and Quantitative data analysis showed that engineering library meet the requirement of comfort zone thermal conditions of ASHRAE standard 55 and ISO 7730. The result shows the environmental condition of the library is neutral to slightly warm in 4-point ASHRAE scale. The linear regression between Predicted Mean Vote and Operative Temperature reveals that the maximum acceptable temperature in this field of study is 26.5ºC.

Passive strategies for climate change mitigation in architectural heritage: the case study of Santa Maria in Trastevere Basilica, Rome

ABSTRACT According to the most recent climate projections, urban settings and historic centres will be affected by considerable increases in temperature extremes and heat waves as a result of climate change. For this reason, the issue of energy efficiency and indoor comfort in historic buildings has become a topic of major interest for the significant number of buildings in the national and European territories. The performance redevelopment of architectural heritage, particularly religious buildings, requires accurate design, through a careful assessment of the occupants’ needs and the historic building’s characteristics, to guarantee adequate levels of thermal comfort and ensure an indoor climate suitable for safeguarding the cultural asset. In this regard, the study investigates, through a data-driven approach and building performance analysis, the indoor comfort level of a religious building in the historical centre of Rome that presents phenomena of excessive indoor overheating. The objective is to identify passive cooling strategies, through the optimization of natural ventilation levels and reduction of surface temperatures of the envelope exposed to solar radiation, in order to propose different design scenarios. The results show how a data-driven process in a digital environment can significantly contribute to the identification of optimal and integrated design strategies and solutions.

Numerical investigation of evaporative cooling strategies on the aero-thermal performance of courtyard buildings in hot-dry climates

In hot and dry urban environments, courtyards help mitigate extreme heat and influence the urban microclimate. These structures not only provide light and private outdoor spaces but also aid in mitigating the urban heat island (UHI) effect through improved airflow and evapotranspiration. Courtyards, being central open-air areas enclosed by buildings, are crucial in creating opportunities for natural ventilation driven by wind and buoyancy-induced forces, thus serving as a microclimatic regulator. This study investigates the role of courtyards in modulating their microclimate and adjacent indoor areas by integrating evaporative cooling strategies to enhance cooling in these spaces. While numerous studies have been conducted on the role of water bodies in evaporative cooling, the aero-thermal impact on adjacent indoor spaces remains less understood. Addressing this gap, the present research explores the effect of an evaporative cooling system on the wind and thermal conditions within a courtyard and examines different natural ventilation modes, namely, single-sided and crossflow ventilation, in indoor spaces. A computational fluid dynamics (CFD) model, validated against wind tunnel experimental data, was employed to simulate various evaporative cooling water spray configurations. The results reveal complex courtyard microclimates with diverse cooling effects influenced by room orientation and floor level. Specifically, in single-sided ventilated courtyards, water sprays significantly improved the indoor thermal environment, with the average temperature across all rooms decreased by 2.06 °C, and humidity increased by 4.29 %. However, in cross-ventilated courtyards, water sprays' cooling and humidifying effects were relatively less effective. This research underscores the potential of evaporative cooling technology in improving the microclimate of courtyards, with practical applications extending to urban design and architecture. By tailoring cooling strategies to specific courtyard configurations, urban planners and architects significantly improve indoor comfort levels and energy efficiency.

Cumulative climate-induced fatigue damage in wooden painted surfaces: The case of wooden churches in Sweden

Environmental variations of Temperature (T) and Relative Humidity (RH) in air cause a superficial and/or sub-surface deformation (shrinkage/swelling) of organic hygroscopic objects, as for example wood. These environmental variations may be due to the natural variability of climate, to the use of Heating, Ventilation and Air Conditioning (HVAC) systems and to the presence of people. This contribution focuses on a group of wooden rural churches located in harsh climates in Sweden. The churches, which are still in use for the local communities, are heated during wintertime to reach acceptable indoor comfort levels causing potentially risky T and RH fluctuations for hygroscopic objects. In this framework, the main goal is assessing the risk of fracture on wooden structural elements caused by hygrothermal fluctuations. The method is based on a preliminary approach for reconstructing the climate history experienced by a typical wooden structural element of these churches and that, over time, results in a cyclic fatigue loading, naturally induced by the outdoor climate. Then, the effect of the artificial heating on the indoor microclimate and, therefore, on the reconstructed fatigue curve is assessed. Main outcomes were obtained by using a methodology that is preliminary based on simplifying assumptions, due to a severe lack of knowledge, in literature, about the fatigue behavior of wood. Finally, main considerations on the fatigue behavior of exposed wooden elements are drawn up, namely the estimation of their residual life (or “life-to-damage”), which may support conservators or church managers in better managing the microclimate to reduce the risk of fracture on valuable objects.

Enhancing indoor comfort and building energy efficiency with cross-laminated timber (CLT) in hygrothermal environments

The hygrothermal behavior of a building is important because it directly influences indoor comfort levels and energy consumption. Hence, effective strategies must be implemented to minimize energy consumption while optimizing indoor conditions. This study analyzed indoor hygrothermal environments and energy consumption in scenarios related to passive and active building elements, such as exterior walls and indoor control temperature. A simulation considering hygrothermal behavior in walls and spaces was utilized, and the accuracy of the model was validated via an on-site test. Here, cross-laminated timber (CLT) walls, which have been proposed for their energy-saving potential, were substituted for conventional concrete walls. The application of CLT walls enhances indoor comfort better than concrete walls. Despite using the same CLT material, different wall layer compositions lead to internal moisture accumulation. Hence, it was determined that appropriate wall layer compositions should be selected based on regional climate conditions. Furthermore, although indoor comfort was ensured by varying indoor control temperatures, the energy consumption of the heating and cooling systems increased by up to 81 %. Despite the application of passive elements, an indoor heating temperature of 24 °C achieves an optimal balance between comfort and energy consumption. This temperature ensured a satisfactory indoor comfort level and facilitated a manageable increase in energy consumption. In summary, this study provides nuanced insights into the hygrothermal dynamics of buildings, emphasizing the demand for strategic materials, considering regional climates, and carefully managing indoor temperatures to strike an effective balance between comfort and energy efficiency.

Analysis of the indoor thermal environment and livability of traditional residences in summer in Northeast Sichuan, China

Abstract With the rapid development of the national economy, increasing attention has been given to the living environment in rural areas, especially indoor thermal and wind environments. This study conducted onsite measurements and questionnaire surveys during summer in the indoor environment of five villages in northeastern Sichuan. A total of 89 traditional residences were selected to investigate their fundamental characteristics, indoor thermal environment, humidity conditions and comfort levels. The results showed that when expressed as neutral temperature and humidity, the temperature difference was 1.35°C and the humidity difference was 8.14%. Local residents exhibited higher tolerance toward the local thermal and humidity environment compared to nonlocal volunteers, who displayed greater sensitivity toward it. In addition, local residents had a thermal comfort value of 0.03 and a thermal acceptance value of 1.16, whereas nonlocal volunteers had a thermal comfort value of 1.42 and a thermal acceptance value of −0.45.

Analysis of the influence of outer envelope structure on indoor thermal environment of zero energy building

Zero-energy building is the main development trend in the current construction field. Reducing the carbon emission of the building, enhancing the indoor comfort of the building, and improving the comprehensive performance of the building are the current research hotspots in the field of construction, and it is necessary to explore the impact of the envelope on the performance of the building as the main medium for the transfer of indoor and outdoor heat in the building. In this paper, zero energy consumption buildings in Northwest China are taken as the study application. Numerical simulation and experimental research are combined to compare and analyze the changes of indoor thermal environment under the conditions of external wall insulation layer thickness of 150mm, 140mm, 130mm and window-wall ratio of 0.36 and 0.5 in the heating season. The results show that the indoor comfort level of 130mm is lower than that of 140mm and 150mm external wall insulation layer thickness, and in winter, the increase of window wall ratio improves indoor thermal comfort. In general, increasing the thickness of external wall insulation layer and window wall ratio can be effective means to improve indoor comfort. However, blindly increasing the thickness of insulation layer and window wall ratio will only cause resource waste and cost increase, affecting the long-term development of zero-energy buildings.

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.

Reinforcement learning-based demand response strategy for thermal energy storage air-conditioning system considering room temperature and humidity setpoints

Heating, ventilation, and air-conditioning systems significantly influence demand response (DR) actions. In the literature, many studies have investigated the reduction of sensible loads through DR events by increasing temperature setpoints while satisfying indoor comfort levels. However, less consideration has been given to latent loads. Therefore, proximal policy optimization reinforcement learning (RL) algorithms are adopted to simultaneously control indoor temperature and humidity (T&H) setpoints to reduce sensible and latent loads. An EnergyPlus-Python joint simulation platform was created for the temperature-humidity independent control system. DR strategies based on RL, active thermal energy storage, and time-of-use electricity prices are formulated to find the optimal indoor T&H setpoints, considering environmental constraints, comfort levels, and energy consumption. The results showed that in the optimal experimental strategies implemented based on negative feedback regulation, savings of 29.15 % on electricity consumption were achieved during DR periods and 46.11 % savings on the daily operating costs. Moreover, a simulation strategy based on feed-forward regulation was developed and found to reduce electricity consumption by 6.92 % during DR periods. Compared with a fixed T&H setpoint, the developed strategy meets the preferences of different groups of people for thermal comfort and increases the system's flexibility.

Operative Temperature Variance and Life Cycle Assessment Impacts of Wall Construction Materials

The overdependence on concrete in the construction industry in sub-Saharan African countries limits the potential use of sustainable materials in the construction of buildings. Hollow Concrete Block (HCB), the industry’s most widely used wall material, contributes to excessive carbon emissions and environmental degradation. Moreso, constructions that employ HCBs, specifically in Nigeria, severely threaten the indoor comfort levels in Naturally Ventilated Spaces NVSs. This study relies on quantitative data to analyse the impact of alternative wall materials in a case building in northern Nigeria. Mud bricks (MB) and Timber/brick (TB) were compared with the existing concrete (CW) case building. The study uses Meteonorm 8 and Climate Consultant 6.0 for EPW file generation. At the same time, dynamic thermal simulation and comparative experiments for thermal comfort and carbon emissions were conducted using DesignBuilder V6 and OneClick Lifecycle assessment tools, respectively. Modelled and simulated under NVS conditions using ASHRAE’s PMV model, the result of the study suggests that the MB alternative, although with an intermediate U-value of 0.318 W/m²k, accounts for the best indoor comfort temperature annually. While the CW building accounts for 41.31% of hours above the comfort temperature of 28⁰C, the TB and MB alternatives account for 29.99% and 27.37% of hours, respectively. Furthermore, the MB alternative is the most environmentally friendly material with 510 KgCO₂/m² emissions, a value 26% less than the CW building with an embodied carbon benchmark of 690 KgCO₂/m² during the building’s life cycle stages. The author suggests that mud construction’s thermal properties and Global Warming Impact (GWI) make it a better alternative to concrete and timber buildings in the tropics.

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.

Research trends in phase change materials (PCM) for high-performance sustainable construction

In the face of escalating environmental perils driven by climate change and global warming, there is an urgent call for innovative and sustainable energy solutions, especially within the construction sector, which is a major consumer of energy and emitter of greenhouse gases. Among various energy-efficient interventions, Phase Change Materials (PCMs) have emerged as a promising technology for passive thermal regulation in buildings. This review paper delves into recent advancements in integrating PCMs within building envelopes, which serve to store thermal energy, thus reducing temperature fluctuations and enhancing indoor comfort levels. The study also underscores the increasing global demand for energy storage systems in pursuit of a low-carbon economy and how PCMs can address this imperative. A special focus is given to applications of PCMs in diverse climatic zones, and the paper offers insights into the thermo-physical properties that make them amenable for building integration. Furthermore, the paper reveals that paraffin wax is the most extensively used PCM and discusses the relevance of selecting PCMs based on their melting points, which is pivotal for optimizing heat transfer efficiency. This study also highlights the need for extensive real-world, full-scale evaluations of PCMs, and the importance of scrutinizing their impact on the mechanical properties of building materials. The lifecycle and cost analyses of PCM integration, which are often overlooked, are identified as crucial areas for further research. Through a comprehensive review of global applications and experimental findings, this paper accentuates the potential of PCMs in revolutionizing building energy efficiency, cooling-heating systems, and integration in concrete, mortar, walls, and solar energy applications while also calling for continued research into performance enhancement and understanding potential drawbacks. This underscores the pivotal role of PCMs in steering the construction industry towards sustainability and energy conservation.

Assessment of Indoor Thermal Condition on Traditional Vernacular Masjid: A Case Study on Masjid Kampung Laut, Malaysia

Traditional vernacular architectures in Malaysia include public buildings such as a masjid were designed with the tropical climate in mind and have proven to be an excellent example of providing indoor thermal comfort to the occupants. It is a naturally ventilated building being greatly influenced by the building designs. In traditional vernacular architecture, the roof is the main building enclosure that contributes to the total heat gain. Hence, the research aims to assess the indoor thermal condition of Masjid Kampung Laut, Kelantan, the first traditional vernacular masjid in Malaysia. Data were collected using the method of field measurement to evaluate the indoor comfort level of the masjid, in terms of indoor air temperature, air velocity, and relative humidity. The results demonstrate that the average indoor air temperature is acceptable and Masjid Kampung Laut responded favorably to the local climate. However, it is believed that with an increase of 0.4m/s to 1.2m/s of air movement, will further enhance indoor thermal comfort. Therefore, the findings can guide further thermal comfort prediction studies for other naturally ventilated buildings. Several other potential passive design strategies for roof design are proposed in this study to achieve acceptable indoor thermal comfort conditions for the masjid in Malaysia.