THE IMPROVEMENT OF ENERGY EFFICIENCY IN AVIATION AND AIR CARGO PUBLIC FACILITIES IN NIGERIA: A CALL FOR POLICY AND SUPPORTIVE REGULATORY FRAMEWORKS

Theoretical Minimum Thermal Load in Buildings

Space Design for Thermal Comfort and Energy Efficiency in Summer

ABSTRACTThis study investigates the viability and benefits of utilizing compressed earth blocks (CEBs) as a sustainable construction material under varying climatic conditions, focusing on two cities in Saudi Arabia: Riyadh, representing a hot desert climate, and Abha, representing a cooler, high‐altitude climate. A comprehensive simulation‐based methodology was employed, which included energy performance modeling and optimization using EnergyPlus software, climate data analysis, environmental impact assessment, and cost analysis. To further verify the results, the EnergyPlus simulations were validated using a machine learning model, specifically the gradient boosting regressor (GBR), to ensure accuracy and reliability. The simulations demonstrate that CEBs provide substantial benefits in terms of structural performance, energy efficiency, and sustainability. For instance, CEB buildings showed reduced cooling loads by 35% in Riyadh and 25% in Abha, while also maintaining high indoor air quality and thermal comfort, leading to 80‐85% occupant satisfaction. The use of CEBs contributed to significant reductions in carbon emissions, with 90% renewable materials, and proved to be cost‐effective over the long term. The GBR validation confirmed less than 2% variation from the EnergyPlus simulations, further ensuring the reliability of the results. Environmental impact assessments revealed substantial reductions in carbon emissions, resource consumption, and waste generation through the adoption of CEBs. Although the initial cost of CEBs may be slightly higher than traditional materials, the long‐term energy savings and reduced maintenance costs make them an economically viable option, particularly in regions with extreme climates. This study underscores the potential of CEBs as a versatile, efficient, and sustainable building material, offering significant benefits in energy efficiency, environmental impact reduction, cost‐effectiveness, and occupant comfort—all based on robust simulation and modeling results.

This study focuses on enhancing indoor air quality and thermal comfort in indoor swimming pool facilities through the investigation of ventilation system configurations. Creating a comfortable and healthy environment in these facilities is crucial for the well-being of occupants and overall operational efficiency. The performance of the ventilation system significantly influences user comfort, energy consumption, and air quality. This research aims to analyze the impact of different ventilation system configurations on indoor air quality and thermal comfort parameters using computational fluid dynamics (CFD) simulations.To achieve the research objectives, CFD simulations were conducted using ANSYS Fluent ®, a widely used commercial CFD package. The simulations involved solving the governing equations for continuity, momentum, energy, and species transport, along with employing the k-epsilon turbulence closure model. A high-resolution mesh with over 5.6 million elements accurately captured the flow regimes and related phenomena.The study investigated various aspects of ventilation system configurations, including the placement and design of inlets and outlets, airflow rates, and distribution patterns. Evaluations were made based on key performance indicators such as indoor air quality parameters, thermal comfort indices, and energy efficiency metrics. Comparisons were made between different configurations to identify the most effective strategies for enhancing indoor air quality and thermal comfort.The findings of the study demonstrate the importance of ventilation system design in achieving optimal indoor air quality and thermal comfort in indoor swimming pool facilities. The results indicate that specific configuration choices, such as the use of circular inlets in the ceiling for improved spectator comfort and rectangular inlets in the side walls for better performance in the swimming pool area, can significantly impact thermal conditions and air distribution. Additionally, the study emphasizes the need for appropriate inlet grille height to ensure adequate air mixing and thermal comfort.The outcomes of this research provide valuable insights for architects, engineers, and facility managers involved in the design, construction, and operation of indoor swimming pool facilities. By understanding the impact of different ventilation system configurations, stakeholders can make informed decisions to optimize indoor air quality, thermal comfort, and energy efficiency. Ultimately, this research contributes to the development of sustainable and comfortable indoor swimming pool environments that cater to the needs of occupants and enhance their overall experience.

PurposeOccupant behavior can lead to considerable uncertainties in thermal comfort and air quality within buildings. To tackle this challenge, the use of probabilistic controls to simulate occupant behavior has emerged as a potential solution. This study seeks to analyze the performance of free-running households by examining adaptive thermal comfort and CO2 concentration, both crucial variables in indoor air quality. The investigation of indoor environment dynamics caused by the occupants' behavior, especially after the COVID-19 pandemic, became increasingly important. Specifically, it investigates 13 distinct window and shading control strategies in courtyard houses to identify the factors that prompt occupants to interact with shading and windows and determine which control approach effectively minimizes the performance gap.Design/methodology/approachThis paper compares commonly used deterministic and probabilistic control functions and their effects on occupant comfort and indoor air quality in four zones surrounding a courtyard. The zones are differentiated by windows facing the courtyard. The study utilizes the energy management system (EMS) functionality of EnergyPlus within an algorithmic interface called Ladybug Tools. By modifying geometrical dimensions, orientation, window-to-wall ratio (WWR) and window operable fraction, a total of 465 cases are analyzed to identify effective control scenarios. According to the literature, these factors were selected because of their potential significant impact on occupants’ thermal comfort and indoor air quality, in addition to the natural ventilation flow rate. Additionally, the Random Forest algorithm is employed to estimate the individual impact of each control scenario on indoor thermal comfort and air quality metrics, including operative temperature and CO2 concentration.FindingsThe findings of the study confirmed that both deterministic and probabilistic window control algorithms were effective in reducing thermal discomfort hours, with reductions of 56.7 and 41.1%, respectively. Deterministic shading controls resulted in a reduction of 18.5%. Implementing the window control strategies led to a significant decrease of 87.8% in indoor CO2 concentration. The sensitivity analysis revealed that outdoor temperature exhibited the strongest positive correlation with indoor operative temperature while showing a negative correlation with indoor CO2 concentration. Furthermore, zone orientation and length were identified as the most influential design variables in achieving the desired performance outcomes.Research limitations/implicationsIt’s important to acknowledge the limitations of this study. Firstly, the potential impact of air circulation through the central zone was not considered. Secondly, the investigated control scenarios may have different impacts on air-conditioned buildings, especially when considering energy consumption. Thirdly, the study heavily relied on simulation tools and algorithms, which may limit its real-world applicability. The accuracy of the simulations depends on the quality of the input data and the assumptions made in the models. Fourthly, the case study is hypothetical in nature to be able to compare different control scenarios and their implications. Lastly, the comparative analysis was limited to a specific climate, which may restrict the generalizability of the findings in different climates.Originality/valueOccupant behavior represents a significant source of uncertainty, particularly during the early stages of design. This study aims to offer a comparative analysis of various deterministic and probabilistic control scenarios that are based on occupant behavior. The study evaluates the effectiveness and validity of these proposed control scenarios, providing valuable insights for design decision-making.

Hot and arid regions require substantial energy to maintain indoor thermal comfort due to extreme climatic conditions. Selection and optimization of building materials offer substantial potential for enhancing energy efficiency and thermal comfort. This study investigates building envelope materials’ impacts on energy efficiency and occupant comfort through multi-objective optimization, evaluating six materials (insulated adobe, adobe, fire bricks, concrete, stone masonry and sintered bricks). In addition to Energy Use Intensity (EUI), Predicted Mean Vote (PMV) and Percentage of People Dissatisfied (PPD), a novel comfort level index is proposed, integrating thermal comfort perception and energy efficiency. This index quantifies both occupant thermal comfort perception and energy effectiveness of achieving such comfort conditions. A case study of Sukkur, Pakistan, using EnergyPlus simulations revealed insulated adobe as the optimal solution. Its Pareto-optimal configuration reduced annual energy consumption by 37.6% compared to concrete while ensuring thermal comfort for occupants. The results highlight that insulated adobe has superior thermophysical properties for balancing energy savings and comfort in hot, arid climates. This framework provides architects and policymakers with a decision-making tool to achieve climate-responsive designs through material optimization, advancing sustainable construction practices. The methodology and index offer theoretical and practical contributions to building performance evaluation.

Energy-Efficient Office Renovation

Essence of indoor thermal comfort and reduction of active power consumption to meet indoor thermal needs has been a keen interest of academia around the globe which has resulted into formulation of strict guidelines for indoor environment requirements in developed countries. Nepal on the other hand lacks the basic provisions when it comes to assuring indoor comfort. Studies shows that unscientific building construction has caused people to depend on changing food and clothing habits to accommodate to the present scenario of indoor environment. The main aim of this study is to address this underlying issue through passive interventions such that both indoor thermal comfort and energy efficiency can be achieved. The study is based on evaluating the effects of various passive and energy efficient building technologies on indoor thermal environment through building energy modeling using EnergyPlus computational engine. Present scenario of indoor thermal environment of residential buildings at Biratnagar and retrofitting measures including insulation, glazing variants, shading, air tightness and others that can enhance indoor thermal comfort whilst enhancing energy efficiency is presented in this paper. In present context, the indoor thermal comfort as indicated by ASHRAE (American Society of Heating Refrigeration and Air Conditioning Engineers) 55 Adaptive Model 80% Acceptability limits is only 32% of total hours in a year, i.e. indoor comfort is compromised for above 5800 hours (equivalent to 8 months) with `hot' to `sweltering' indoor environment. Effects of 8 passive design interventions on residential building was analyzed based on the thermal load reduction potential and increase in acceptable limits of indoor comfort hours. It was found that combination of various design changes would help achieve up to 86% indoor thermal comfort hours and reduce annual thermal load by 68% relative to the base case scenario The study shows that incorporating passive techniques on Nepalese residential buildings can assure indoor comfort and reduce active heating/cooling demand.

The indoor environmental quality (IEQ) and occupant comfort are closely related. The current indoor environmental assessment includes four aspects, namely thermal comfort (TC), indoor air quality (IAQ), visual comfort (VC) and aural comfort (AC). IAQ, as the nature of air in an indoor environment with relation to the occupant health and comfort is not an easily defined concept. In a broad context, it is the result of complex interactions between building, building systems and people. Comparative risk studies performed by the United States Environmental Protection Agency (USEPA) ranked IAQ as one of the 5 top environmental risks to the public health. Over the past decades, exposure to indoor air pollutants increased due to a variety of factors including: construction of tightly sealed buildings, reduction of ventilation rates (for energy saving) and use of synthetic building materials and furnishings as well as chemically formulated personal care products, pesticides and household cleaners. The effect of chemical pollutants on the perceived IAQ was investigated in several studies. The volatile organic compounds (VOCs) were suspected to cause ‘‘sick-building’’ symptoms, like headache, eye and mucous membrane irritation, fatigue and asthmatic symptoms (Redlich et al. 1997). The WHO air quality guidelines exist for major ambient air pollutants such as nitrogen dioxide and ozone, a few organic pollutants including mainly chlorinated and aromatic hydrocarbons (World Health Organization, 2000). The International Agency of Cancer Research recently upgraded formaldehyde to the group 1, known human carcinogen (IARC, 2004). However, there are still inadequate data about health effects of other VOCs. The total amount of VOCs and TVOC was not proven to correlate with symptoms. Investigations of all types of indoor air pollutants for the general air quality monitoring and assessment are complicated. In many studies, it was suggested that the measurement and analysis of the indoor carbon dioxide (CO2) concentration could be useful for understanding the Indoor Air Quality (IAQ) and ventilation effectiveness. Healthy people can tolerate the CO2 level up to 10,000 ppm without serious health effects. An acceptable indoor CO2 level should be kept below 1000 ppm or 650 ppm above the ambient level in order to prevent any accumulation of associated human body odors. The indoor carbon dioxide is relatively easy to measure and its low level in the indoor air usually corresponds to a low level of VOCs.

Energy-Efficient Office Renovation

One-year Field Study on Indoor Environment of Huizhou Traditional Vernacular Dwellings in China

On the potential of demand-controlled ventilation system to enhance indoor air quality and thermal condition in Australian school classrooms

Indoor environmental quality profoundly impacts student learning outcomes and teacher effectiveness, particularly in primary education, where children spend most of their developmental years. The study compares the New Zealand Ministry of Education’s Designing Quality Learning Spaces (DQLS) version 2.0 for primary school classrooms with international standards set by OECD countries to develop IAQ and thermal comfort best practices in New Zealand across six climate zones. The research evaluates indoor air quality (IAQ) and thermal comfort factors affecting students’ and teachers’ health and performance. Using Ladybug and Honeybee plugin tools in Grasshopper with Energy Plus, integrated into Rhino 7 software, the study employed advanced building optimisation methods, using multi-criteria optimisation and parametric modelling. This approach enabled a comprehensive analysis of building envelope parameters for historical classroom designs, the Avalon block (constructed between 1955 and 2000). Optimise window-to-wall ratios, ceiling heights, window placement, insulation values (R-values), clothing insulation (Clo), and window opening schedules. Our findings demonstrate that strategic modifications to the building envelope can significantly improve occupant comfort and energy performance. Specifically, increasing ceiling height by 0.8 m, raising windows by 0.3 m vertically, and reducing the window-to-wall ratio to 25% created optimal conditions across multiple performance criteria. These targeted adjustments improved adaptive thermal comfort, ventilation, carbon dioxide, and energy efficiency while maintaining local and international standards. The implications of the findings extend beyond the studied classrooms, offering evidence-based strategies for overall design and building performance guidelines in educational facilities. This research demonstrates the efficacy of applying computational design optimisation during early design phases, providing policymakers and architects with practical solutions that could inform future revisions of New Zealand’s school design standards and align them more closely with international best practices for educational environments.

Maintaining good indoor air quality and thermal comfort is a challenge for naturally ventilated educational buildings, as it can be difficult to achieve both aspects simultaneously. Nonetheless, most of the existing studies only focus on one aspect. To explore the potential of balancing indoor air quality and thermal comfort, both topics must be investigated concurrently. This study assessed indoor air quality and thermal comfort in 32 naturally ventilated classrooms of 16 primary and secondary schools in the Mediterranean climate, based on a large on-site measurement campaign lasting one year that gathered over 460 hours of data. The research investigated occupants’ adaptive behaviors, analyzed the actual thermal comfort of around 600 students, and characterized the representative scenarios leading to good and poor indoor air quality and thermal comfort by clustering analysis. The results showed that poor indoor air quality was mainly due to closing windows and doors in winter, while thermal discomfort mainly occurred in summer because of the high indoor temperature. The findings suggested that a proper ventilation protocol is the key to balancing indoor air quality and thermal comfort.

With growing popularity of green building rating systems, LEED and GSAS projects are becoming a building industry standard in Qatar. Furthermore, more projects targeting higher rating in green building certification has become a trend. A large number of green buildings have been focused on in terms of energy and water efficiency, where a high level of certification can be achieved and their performance can be easily translated and expressed into numeric terms. Media tends to highlight efficiencies in green buildings that are broadcasted as high-performance buildings. Although non-quantifiable benefits of green buildings such as enhanced occupant's productivity, health and comfort are equally important, emphasis on human factor has drawn relatively less attention to the green building design process. Considering the significance of cost incurred for building occupants in facility operation, worker's wages and expenses are much higher than the utility cost or any other operation costs. Especially, low energy and water tariffs in Qatar actually lower financial feasibility of high energy and water performance green buildings than those in other countries. In addition, due to hot weather conditions in Qatar, people spend more hours indoor than outdoor compared with other climate zone countries. In this regard, building occupant's health and comfort should be more importantly treated in the context of green building in Qatar. According to a study on Qatari public health, a large percentage of students in Qatar experience allergic diseases (asthma, allergic rhinitis and eczema) and communicable diseases (influenza and hepatitis). Such diseases result in absenteeism and poor academic performance. Knowing that Doha was ranked the 12th worst ambient air quality in fine particles by the World Health Organization (WHO) in 2014, prevalence of such diseases indicates that indoor environment is not sufficiently protected from polluted outdoor conditions. The diseases eventually burden the national healthcare cost to attend patients and potentially deteriorate Qatari businesses as well as education performance resulted from high absenteeism. This paper aims to first understand the level of the occupant's satisfaction in indoor air quality and thermal comfort based on a survey questionnaire for typical operating buildings in Qatar, and strives to find the correlation between indoor environment quality in Qatari buildings and locally prevalent allergic and communicable diseases. The study finally aims to determine the root causes of health-related indoor environmental quality issues and to suggest improvements in design, construction and operation of a green building implementation.