Journal of Architectural Engineering

Owing to the recent global emergence of COVID-19 and its effects on education, particularly in Saudi Arabia, schools in the Kingdom have adopted online virtual learning styles. This is a quick reaction to the government’s decision to close all schools to control the spread of the coronavirus. This study examines the effects of virtual learning on architectural engineering and architecture education in the context of Saudi Arabia’s Pandemic Lockdown. The study collected population-representative survey data from 146 eligible respondents via a five-scale Likert questionnaire survey distributed among Saudi university students. The statistical package SPSS 28.0 was used to analyze the results, which included simple descriptive statistics and Spearman’s correlation. The study discovered that the pandemic had affected architecture and architectural engineering teaching and learning pedagogy, online assessment and examination, the environment and resources for teaching and learning, and the future application of online teaching and learning. The study reveals a strong reluctance to recommend online learning in the future for both studio- and lab-type lessons, because the available online learning hardware tools for studio-type instruction are insufficient. The findings of this study will help handle various architecture and architectural engineering courses in times of emergency that necessitates switching to online classes.

Green roofing technologies have been developed and implemented worldwide as they bring with them thermal, hydrological, and environmental benefits, especially in urbanized areas. Many studies have been conducted to investigate the thermal performance of green roofs over reinforced cement concrete (RCC) structural bases but there is a lacuna of experimental evaluation of the thermal performance of green roofs on sloping galvanized iron (GI) sheet truss type roof structures. In this paper, the thermal performance of a retrofitted extensive green roof is quantified; this is challenging in subtropical climates because of extreme seasonal and diurnal variations. The thermal performance of the green roof system was assessed using a life-size experiment setup followed by a whole-building simulation using Design Builder, which runs on the EnergyPlus simulation engine. Two prototype roofs were analyzed and the performance of the retrofitted extensive green roof was compared with that of a conventional RCC roof solution. To validate the results, two prototype buildings were constructed at a university campus and their thermal and energy performance analyzed for two observation periods, one during a typical summer week and the other during a typical winter week. The extensive retrofitted green roof displayed enhanced thermal and energy performance at a nominal additional cost. The findings of this study can be deployed in the development of a retrofitted extensive green roof module for sloped GI sheet roofs for better thermal performance, and hence reduced energy loads, and meet the sustainable development goals.

Abstract

Gun ranges in the United States are underinvestigated regarding indoor air quality (IAQ) and energy efficiency. Navy Environmental Health Center (NEHC), National Guard Bureau (NGB), and Air Force Civil Engineer Support Agency (AFCESA) recommend using 100% outdoor air, but this measure will cause prohibitive energy costs since indoor gun ranges must maintain a low air velocity ranging from 0.25 to 0.36 m/s and a supply temperature close to the range target temperature. Hence, typical commercial firing ranges use a fixed outdoor air ratio (OAR) ranging from 25% to 30% together with high-efficiency particulate air filtration to save energy. This OAR is arbitrary and not supported by any standards or guidelines. To obtain reliable control of contaminant levels and better energy efficiency, we propose a model-based demand control ventilation feedback control strategy in which carbon monoxide is monitored and controlled as a proper IAQ indicator around the clock. Our 52-day field study demonstrates that our demand control ventilation control strategy can ensure proper IAQ, reduce the OAR from 30% to as low as 2.5%, and cut up to 85% cooling load and 70% heating load introduced by ventilation.

Practical Applications

Indoor gun ranges in the United States often struggle with keeping the air clean and energy costs down. Existing recommendations suggest using a lot of outdoor air for ventilation, but this can be expensive because gun ranges need to maintain specific air conditions. Most gun ranges use a fixed amount of outdoor air and special filters to save energy, even though there are no clear guidelines for this. To tackle these issues, we have come up with a smart ventilation system. It constantly checks the air for carbon monoxide, a sign of bad air quality. Our 52-day study showed that this system works considerably well. It keeps the air clean, reduces the need for outdoor air substantially, and cuts down on heating and cooling costs. This means that indoor gun ranges can have clean air and save energy at the same time. It is a practical and efficient solution for making indoor shooting ranges safer and more cost-effective.

Abstract

The supply airflow rate is crucial for monitoring, controlling, and detecting faults in rooftop air conditioner units (RTUs). However, the cost and intrusiveness of a supply airflow rate sensor (SARS) make it difficult to deploy in the field. Virtual SARSs have been proposed, but they often require testing or experimentation to train the model, which is not easily scalable. To overcome this limitation, the present study proposed deriving supply airflow using publicly available and scalable original equipment manufacturer (OEM) data of RTU blowers. Two models, the gray-box, and the black-box, were proposed using the OEM data and applied to data from four different manufacturers. Despite limited OEM data, the gray-box model showed an accuracy of ±5%, while the black-box model provided high overall accuracy for the full range of data but yielded low accuracy (up to 27% error) at a lower blower rotation speed. The models were also validated through laboratory testing, with an accuracy of ± 10% for the motor speed range of 50%–100% of the rated speed.

Practical Applications

Monitoring and controlling the airflow rate in rooftop air conditioner units (RTUs) is essential, but traditional sensors for this purpose are costly and intrusive, making them challenging to use in the real world. To address this issue, researchers have proposed virtual sensors that estimate airflow without physical sensors, but these often require complex training processes that are not easily scalable. In this study, a novel approach is introduced. It leverages readily available data from RTU manufacturers (OEM data) to estimate airflow. Two models, known as the gray-box and the black-box models, are developed using this OEM data and tested on data from four different RTU manufacturers. The gray-box model, despite limited OEM data, achieves impressive accuracy within ±5%. The black-box model performs well overall but struggles with lower blower rotation speeds, resulting in up to a 27% error. To validate the models, laboratory tests were conducted, confirming an accuracy of ±10% for motor speeds ranging from 50% to 100% of the rated speed. This research offers a promising and cost-effective solution for accurately estimating supply airflow rates in RTUs, making it easier to monitor and control these systems efficiently.

The present study focuses on the innovative technique for making rectangular and circular hollow concrete blocks using fly ash (FA) and recycled concrete aggregates (RCA). The feasibility of employing RCA in conjunction with fly ash as a substitute for natural aggregates and cement in a proportion ranging from 30%–90% and 15%–45%, respectively, is tested in the laboratory. According to current standards, the tests comprise the slump test, compressive strength test, water absorption test, and structural efficiency evaluation. An empirical quantitative technique is used for the cost–benefit analysis of a 100-square-foot model built with recycled concrete hollow blocks. The study suggests that employing recycled concrete aggregate and fly ash as replacements for conventional materials would result in a minimum cost savings of 17%. The quantity of greenhouse gases produced in CO₂ equivalents during concrete production is calculated using the Inventory of Carbon and Energy database. According to research findings, the utilization of recycled concrete aggregates and fly ash reduced carbon dioxide equivalent emissions by 30%–40%. It was also confirmed that cement has a major effect on greenhouse gas emission generation throughout the concrete manufacturing phase, regardless of the use of RCA over virgin aggregates. This study intends providing a significant understanding of how RCA and FA can not only contribute to environmental conservation but also offer economic benefits. Finally, the research intends to encourage the adoption of ecologically responsible and economically viable sustainable practices in the construction industry.

As cities and economies grow, energy demands also grow, especially in developing countries, given the material production, construction, and operational processes of buildings and cities. Since the recent Powerhouse standard assumes that a building can generate as much energy as it will require during its lifespan, the present study aimed to implement this building standard in the Andean equatorial climate. For this purpose, a building energy model (BEM) integrated into a building information modeling (BIM) process design method was proposed, developing a prototype with vernacular technology, high solar potential, and local or regional data on embodied energy in accordance with a life cycle assessment (LCA) from cradle to grave. Solar potential estimations were complemented by system advisor model (SAM) tool projections. Because of the low energy content of the vernacular architecture proposal and prototype development with a high generation capacity, this standard can be met six times faster in the Andean equatorial climate than in extreme seasonal climates (8.53 years versus 60.0 years). The main goal of our research was to propose a methodological approach that integrates the BEM tool with vernacular concepts and materials and architectural formal criteria for high solar exploitation that, with background data from the literature, makes it possible to decipher the capability of the proposed energy standard.

Continual two-year measurements of daylight illuminance were performed in order to evaluate the daylighting of a model room. The key research idea was to study room orientation and its effect on daylight availability by using real measurements from a physical scale model. Firstly, differences between the illuminance in the north- and south-oriented rooms were compared. Secondly, a characteristic annual profile of the external horizontal illuminance data was determined. Finally, the median external diffuse illuminance data from measurements were compared with values based on the values recommended in the standard. The goal of the research was focused on the evaluation of a regional daylight climate model applicable for daylight evaluations. The results of the daylight illuminance measurements showed the importance of climatic daylight data for indoor daylighting in building design performance.

The construction industry plays a significant role in shaping our environment and economy. However, it also substantially impacts the environment, including the depletion of natural resources, increased energy consumption, and waste generation. The green building trend has recently gained significant attention in recent years to mitigate the negative impacts of the building industry, focusing on sustainable materials and practices. One of the primary materials used in this field is clay brick, which leads to soil depletion over time. In this context, this study explores the potential of sawdust waste as a partial replacement for clay in brick production, aiming to reduce the depletion of natural resources while enhancing the properties and performance of the produced bricks. The study consists of two main phases: experimental and simulation. In the experimental phase, clay brick samples were produced by adding sawdust at different ratios (1%, 2%, 4%, 8%, and 10% of the raw weight), and various physical and mechanical properties of the produced samples were tested to ensure their suitability for construction use. Also, the thermal properties of the proposed brick were measured to investigate the effect of sawdust addition on brick thermal insulation. Consequently, thermal conductivity and specific heat were measured. In the simulation phase, DesignBuilder software (version 7.0.2) was used to investigate the impact of the proposed material on building envelope’s performance and heat gain reduction. All experimental and simulation results were compared with the traditional clay brick measurements, which reveal a significant improvement in brick properties and performance with an increase in comprehensive strength of up to 192.3% and a reduction in energy consumption reaching 11.27%. The study results showed significant improvement in the properties and performance of the produced bricks, indicating the potential of using sawdust waste as a sustainable material for green buildings.

As the current environmental crisis and depletion of our energy resources are pushing the Architecture, Engineering, and Construction (AEC) industry toward the design and construction of High-Performance (HP) buildings, new organizational and technological methods of practice, such as Integrated Design Process (IDP) and Building Information Modeling (BIM), have emerged to facilitate this transition. Consequently, Architecture schools are left with the duty of training practitioners with the required holistic vision and technical knowledge for designing HP buildings, technological abilities to work with new BIM tools, collaboration skills to work with cross-disciplinary team members, and theoretical knowledge to run the new processes. Scholars of architectural education are faced with a significant theoretical and practical knowledge gap on how to add all these new layers of knowledge and skills to what is an already saturated curriculum in architecture schools. To address this need, we developed a conceptual framework for teaching an integrated and BIM-based HP design studio for the MS program in Building Science. The experience was successful in creating an effective systematic method for integrating HP design elements in the students’ projects, with all the teams achieving their project performance targets in six distinct HP categories of energy consumption, greenhouse gas emissions, health and wellbeing, water management, and resiliency, while meeting reasonable architectural qualities and economic criteria. The key elements of this pedagogical approach, including teamwork, a structured and iterative design process, decision-making mechanism with a high level of attention given to various performance metrics, the use of related BIM technologies, and the evaluation techniques, are introduced, discussed, and recommendations are proposed for future applications.