Strategies towards reducing carbon emission in university campuses: A comprehensive review of both global and local scales

Universities and other Higher Education Institutions (HEIs) have a key role to play in promoting decarbonisation and sustainable development. The implementation of low-carbon and energy-efficient strategies in colleges and University Campuses (UCs) is of utmost importance, as the number of these buildings continues to grow rapidly worldwide. This paper uses an organized search strategy for reviewing the most impactful previous studies regarding decarbonisations strategies in UCs in different climate contexts. This research presents a comprehensive overview of influential parameters, which are practical to be considered in designing new or retrofitting existing UCs which has not been done before and also highlights relevant policies and guidelines required to implement these parameters. These factors are spatial planning and landscape, renewable and clean energy, energy systems, thermal envelope, green transportation, management and control, human-related performance and smartness. This review also explores the recent trends in the decarbonisation of UCs such as the application of smart technologies and implementation of real-time data-based control and management technologies. Finally, this review presents the research gaps, future trends and technologies which will facilitate the decarbonisation of UCs. This review would help researchers and designers to facilitate the transition towards net-zero carbon future in university campuses

A comprehensive review of outdoor thermal comfort in urban areas: effective parameters and approaches

Increased urban air temperature considerably affects the health, comfort and consequently the quality of life in urban spaces. Urban design and planning studies, therefore, face an increasing challenge as they aim to improve Outdoor Thermal Comfort (OTC) and microclimate conditions of urban environments. Analysing OTC is more challenging when compared to indoor thermal comfort since a wider range of interrelated parameters exists in outdoor environments. Therefore, this research aims to classify urban studies that investigate OTC by conducting a comprehensive review based on key metrics such as approaches taken, methodologies and spatial and temporal scales. By extracting the key findings, this research forms an integrated framework of these metrics that presents a thorough view of the OTC concept in the context of climate-sensitive studies. Furthermore, this research elaborates on the main two groups of parameters affecting OTC including environmental and human-based parameters. Exploring the intricate inter-relationships of these two groups of parameters clarifies their contribution to OTC. Results of this study help architects and urban planners to improve their climate-sensitive strategies and support the decision-making process by providing a comprehensive perspective about different aspects of OTC. Finally, recommendations for future research are outlined

Factors influencing radon concentration during energy retrofitting in domestic buildings: a computational evaluation

The findings of recent research signalled increased radon levels following energy retrofitting of dwellings but to date, there have been limited quantitative data to support this observation. A modelling framework was developed that incorporates a dynamic radon entry rate, capturing changes in pressure differentials, to investigate changes in radon concentration following different energy-efficient retrofit measures in naturally-ventilated dwellings. Simulations examined a range of input criteria: dwelling type, air permeabilities, radon flow exponents, pre and post thermal retrofit characteristics, outdoor weather locations and corresponding wind profiles, as well as different ventilation guidelines. A total of 3,780 simulations were carried out. The air permeability of the building had the greatest impact on radon concentration with increases of up to 107%. Non-linear increases were observed arising from the impacts on pressure differentials due to changes in air permeability. The application of representative weather profiles associated with different locations (e.g. coastal, inland) resulted in differences of up to 37%. To a lesser extent, increased indoor temperature due to thermally retrofitting the building fabric, without changes in air permeability, resulted in radon levels increasing by 7%. Additionally, it was shown that the radon flow exponent was not a significant influence on radon concentrations following a retrofit. The addition of ventilation measures means that it is possible to achieve increased airtightness without impacting on the radon concentration. Overall, the simulations provide quantitative information that explains increased airtightness and elevated radon levels, highlighting the potential for radon concentrations to either increase or decrease following an energy retrofit

Feasibility analysis of community-based PV systems for residential districts: A comparison of on-site centralized and distributed PV installations

Photovoltaic systems are one of the most promising renewable energy technologies for on-site generation. Most of the techno-economic studies consider distributed standalone photovoltaic generation with little consideration of community-based standalone photovoltaic systems. Location-based case studies are required to provide economic and reliable photovoltaic systems to meet the peak loads of residential neighbourhoods in an optimized manner. This paper devises an integrated evaluation methodology; a combination of white-box energy modelling and black box photovoltaic design optimization. This research uses optimization methods to develop a quantitative optimized model for analysing the opportunities of centralized systems to adequately meet the demands of a residential neighbourhood and support the grid. This analysis includes three metrics including the level of the energy production, reliability of system for peak power and finally the capital cost of implementation in residential districts. Results indicate that the size of a centralized photovoltaic installation is less when compared to distributed installations to support a similar single peak load. The required converter size is reduced for the centralized system owing to the reduced system size. Centralized installations require fewer batteries to store surplus energy produced due to increased interaction of energy flows. Centralized installations are economically more viable than distributed ones.Science Foundation IrelandUniversity College DublinESIPP UC

A Review of District-scale Energy Performance Analysis: Outlooks towards Holistic Urban Frameworks

Over the past few decades, the world has experienced a major population shift towards urban areas resulting in environmental degradation and increased energy consumption. To combat these challenges, energy efficiency measures are being deployed to improve the performance of different entities within urban built environments. However, effective implementation of such measures often requires a holistic approach to account for existing interrelated and complex relationships between entities at the urban scale. This paper presents a distillation of salient facts and approaches for energy performance evaluation of districts. The studies are reviewed in three sections; (1) concepts defining district energy performance, (2) approaches and methodologies for district energy performance evaluation and (3) system interactions between district entities. The state of the art review reveals that several challenges exist in the initial stages of energy performance assessment of districts. The suggested framework in this paper addresses this issue through pre-processing of data related to entities such as transportation systems and buildings. The framework classifies the available information under three potential categories, namely, 'subject and Scope’, ‘Input Data Management’ and ‘Methods’. This categorisation results in easier integration of multidisciplinary aspects of entities involved in district energy performance assessment.Science Foundation Irelan

Airborne and aerosol pathogen transmission modeling of respiratory events in buildings : An overview of computational fluid dynamics

Publisher Copyright: © 2022 Elsevier LtdPathogen droplets released from respiratory events are the primary means of dispersion and transmission of the recent pandemic of COVID-19. Computational fluid dynamics (CFD) has been widely employed as a fast, reliable, and inexpensive technique to support decision-making and to envisage mitigatory protocols. Nonetheless, the airborne pathogen droplet CFD modeling encounters limitations due to the oversimplification of involved physics and the intensive computational demand. Moreover, uncertainties in the collected clinical data required to simulate airborne and aerosol transport such as droplets’ initial velocities, tempo-spatial profiles, release angle, and size distributions are broadly reported in the literature. There is a noticeable inconsistency around these collected data amongst many reported studies. This study aims to review the capabilities and limitations associated with CFD modeling. Setting the CFD models needs experimental data of respiratory flows such as velocity, particle size, and number distribution. Therefore, this paper briefly reviews the experimental techniques used to measure the characteristics of airborne pathogen droplet transmissions together with their limitations and reported uncertainties. The relevant clinical data related to pathogen transmission needed for postprocessing of CFD data and translating them to safety measures are also reviewed. Eventually, the uncertainty and inconsistency of the existing clinical data available for airborne pathogen CFD analysis are scurtinized to pave a pathway toward future studies ensuing these identified gaps and limitations.Peer reviewe

Definition of a useful minimal-set of accurately-specified input data for Building Energy Performance Simulation

Developing BEPS models which predict energy usage to a high degree of accuracy can be extremely time consuming. As a result, assumptions are often made regarding the input data required. Making these assumptions without introducing a significant amount of uncertainty to the model can be difficult, and requires experience. Even so, rules of thumb from one geographic region are not automatically transferrable to other regions. This paper develops a methodology which can be used to determine useful guidelines for defining the most influential input data for an accurate BEPS model. Differential sensitivity analysis is carried out on parametric data gathered from five archetype dwelling models. The sensitivity analysis results are used in order to form a guideline minimum set of accurately defined input data. Although the guidelines formed apply specifically to Irish residential dwellings, the methodology and processes used in defining the guidelines is highly repeatable. The guideline minimum data set was applied to practical examples in order to be validated. Existing buildings were modelled, and only the parameters within the minimum data set are accurately defined. All building models predict annual energy usage to within 10% of actual measured data, with seasonal energy profiles well-matching.European Commission - Seventh Framework Programme (FP7)Science Foundation IrelandScience Program Without Borders/CAPES - Brazil24 month embargo- ACUpdate issue date during checkdate report - A