Rooftop Area Research Articles

A Study on the Indoor Heating Effect of Blue Green Roofs during Cold Waves

With the increasing frequency of heat-based climate disasters due to recent climate change, various technologies are being developed to mitigate their impacts. Blue-green roofs (BGR) is a technology that consists of rainwater storage tanks and grass layers installed on building rooftops to reduce the infiltration of cold or heat into the building interiors. This study analyzed the indoor temperature changes between two buildings with equal rooftop area, one equipped with a BGR and the other without, during winter season to evaluate their heating effects. The results indicated an average heating effect of 0.56 °C across the entire monitoring period for the building with a BGR. The heating effect was observed only at temperature ranges below 6.5 °C, with no effect at higher temperatures. This study suggests that even installing a roof-based system can provide some degree of heating benefits. Further research and development are needed to improve the heating efficien through additional technological advancements.

Evaluation of photovoltaic installation potential in industrial complexes around metropolitan areas: Regulatory obstacles and geographical considerations

The assessment of photovoltaic (PV) installation potential in industrial complexes is critical for advancing renewable energy objectives, particularly in urbanized settings like Gyeonggi Province, South Korea. This study examines the complex interaction of geographical, regulatory, and environmental factors affecting PV feasibility across 193 industrial complexes. Employing a GIS-based methodology, the research evaluates available rooftop and general land areas totaling 47.3 km2, estimating a PV capacity potential of 3.72 GW. Despite significant rooftop spaces predominantly on concrete structures (10 km2), stringent setback regulations present substantial obstacles, particularly in areas such as Ansan. General land sites covering 16.6 km2 offer promising prospects, notably in Pyeongtaek. Current regulatory challenges, including setback regulations, impede the realization of the targeted 3.8 GW PV capacity, highlighting the potential benefits of policy reforms to facilitate deployment. This study underscores PV's pivotal role in sustainable energy transitions and advocates for strategic reforms to align regulatory frameworks with renewable energy aspirations. By integrating GIS analyses with regulatory insights, the study informs spatial planning initiatives essential for scaling up solar energy contributions in industrial contexts, supporting informed decision-making toward achieving a low-carbon future.

Prioritizing social vulnerability in urban heat mitigation.

We utilized city-scale simulations to quantitatively compare the diverse urban overheating mitigation strategies, specifically tied to social vulnerability and their cooling efficacies during heatwaves. We enhanced the Weather Research and Forecasting model to encompass the urban tree effect and calculate the Universal Thermal Climate Index for assessing thermal comfort. Taking Houston, Texas, and United States as an example, the study reveals that equitably mitigating urban overheat is achievable by considering the city's demographic composition and physical structure. The study results show that while urban trees may yield less cooling impact (0.27 K of Universal Thermal Climate Index in daytime) relative to cool roofs (0.30 K), the urban trees strategy can emerge as an effective approach for enhancing community resilience in heat stress-related outcomes. Social vulnerability-based heat mitigation was reviewed as vulnerability-weighted daily cumulative heat stress change. The results underscore: (i) importance of considering the community resilience when evaluating heat mitigation impact and (ii) the need to assess planting spaces for urban trees, rooftop areas, and neighborhood vulnerability when designing community-oriented urban overheating mitigation strategies.

Urban greening in Dhaka: Assessing rooftop agriculture suitability using GIS and MCDM techniques

Dhaka ranks among the world's most densely populated cities, with built-up areas expanding to accommodate the demands of a growing population. The rapid urbanization has reduced green space and exacerbated urban heat and pollution in the city. In the quest for a greener and healthier urban environment, rooftop agriculture has emerged as a promising solution, offering opportunities for the restoration of the environment and safe food production. Despite its potential, limited studies have explored the viability of this alternative greening solution for Dhaka. Therefore, this study aims to assess the suitability of rooftops for agricultural activities employing Geographic Information System (GIS) and Multi-Criteria Decision Making (MCDM) techniques. First, seven criteria were selected based on the literature, such as building age, height, rooftop size, building utility, property value, sunlight, and water availability. Second, an expert opinion survey was conducted using the Best Worst Method (BWM) to calculate the criteria's weights. Finally, the suitability map for Dhaka was derived by combining the criteria layers and was subsequently validated. Rooftop area and property value were identified as the most and least important criteria. Approximately 9% (6.27 km2), 68% (46.59 km2), 22% (15.15 km2), and a negligible portion (0.1 km2) of Dhaka city has been classified as highly suitable, suitable, moderately suitable, and not suitable, respectively, for rooftop agriculture. By identifying and promoting the most suitable locations for rooftop agriculture and highlighting existing opportunities, this research will help to initiate and expand sustainable agriculture practices that can contribute to climate change adaptation and urban resilience.

ASSESSING the POTENTIAL of RAINWATER HARVESTING and REUSE for SUSTAINABLE UNIVERSITY CAMPUS

Water resource management, one of the paradigms for creating sustainable universities, ensures that universities both manage the quantity of water used and maintain the quality of water. Water resource management models that begin with campus priority create input for cities at a higher scale. Water resource management encompasses a variety of sustainable practices. One of the most applicable is the reuse of rainwater. Based on these findings, the main objective of the study is to re-evaluate the rainwater harvested with proposed solutions on site and contribute to nature and the water cycle. In the study, the “Rational Method” was used as the method for calculating the amount of rainwater. Hardscape (roads, parking lots), landscaped areas (landscaped and wooded areas) and roofing materials within the campus were determined. The efficiency coefficients of the materials were determined. The area occupied by each material was calculated. The total amount of rainwater was calculated by multiplying by the rainfall data. Studies on rainwater harvesting usually only calculate the amount harvested from roof surfaces. This study calculated the amount of rainwater harvested from hardscape, landscape and rooftop areas. In one year, an average of 243,000 liters of water is needed to use the reservoir and 54,530,000 liters of water for plant irrigation. The total water consumption was calculated at 54,773,000 liters. The annual rainwater volume is 494,000,000 liters and the useful volume is 296,400,000 liters. It can be seen that a volume is achieved that is approximately 5 times the amount of water required.

Photovoltaics Energy Potential in the Largest Greek Cities: Atmospheric and Urban Fabric Effects, Climatic Trends Influences and Socio-Economic Benefits

This comprehensive study explores the influence of aerosols and clouds on solar radiation in the urban environments of nine of Greece’s largest cities over the decade from 2014 to 2023. Utilizing a combination of Earth Observation data, radiative transfer models, and geographic information systems, the research undertook digital surface modeling and photovoltaic simulations. The study meticulously calculated the optimal rooftop areas for photovoltaic installation in these cities, contributing significantly to their energy adequacy and achieving a balance between daily electricity production and demand. Moreover, the research provides an in-depth analysis of energy and economic losses, while also highlighting the environmental benefits. These include a reduction in pollutant emissions and a decrease in the carbon footprint, aligning with the global shift towards local energy security and the transformation of urban areas into green, smart cities. The innovative methodology of this study, which leverages open access data, sets a strong foundation for future research in this field. It opens up possibilities for similar studies and has the potential to contribute to the creation of an updated, comprehensive solar potential map for continental Greece. This could be instrumental in climate change mitigation and adaptation strategies, thereby promoting sustainable urban development and environmental preservation.

Assessment of rainwater harvesting potential from rooftops in Jordan's Twelve Governorates.

Rooftop rainwater harvesting (RRWH) offers a potential solution to Jordan's pressing water scarcity problems. Yet, its feasibility and benefits necessitate a thorough assessment, particularly as existing studies on the subject are outdated and often constrained by limited scope or small data sets. To this end, our study assessed the potential of RRWH in Jordan's 12 governorates, utilizing historical rainfall data from 1987 to 2018 and official statistics on population and rooftop areas. The analyses used the Ripple Method and Water Balance Model to determine potential harvestable water volumes, potential water-saving percentages, and optimal tank sizes under different scenarios (i.e., using rainwater to meet the total consumption or only for toilet flushing). The findings reveal that Jordan has a total potential for rooftop rainwater harvesting amounting to 23.74 Mm3/year, corresponding to 4.54% of the total water demand. Should RRWH be implemented across all rooftops, the projected financial savings for Jordan could range from $170 million to $678 million. Among the governorates, Irbid and Amman have the highest potential, with estimated yields of 7.754 Mm3 and 8.453 Mm3 per year, respectively. Based on the best results for the scenario where harvested rainwater is only used to flush toilets, the optimal tank sizes for storing rainwater were estimated to be 2.7 m3 and 2 m3 per household in Ajlun and Irbid, respectively. For a regularized case (October-May), a payback period of 12.5-24 years based on desalination cost was found for an RRWH system capable of meeting thrice the flushing needs of a household. RRWH was showcased as a sustainable solution to Jordan's water scarcity, emphasizing the necessity for broader implementation.

Harnessing rooftop solar photovoltaic potential in Islamabad, Pakistan: A remote sensing and deep learning approach

Solar energy shines as a beacon for sustainable development, with rooftop solar photovoltaic (PV) installations playing a crucial role. This study proposes a novel framework to precisely assess citywide existing solar power generation and analyze future potential under various rooftop utilization scenarios (10–50 %). To illustrate the methodology, the existing solar PV yield and future potential of Islamabad are explored as a case study. Employing open-source satellite data and deep learning (DL), this study quantified the electricity generation from current solar infrastructure and projected future possibilities. DL models like Mask R–CNN and Deeplab-v3 are trained on extensive custom datasets for solar panels and rooftops extraction. The study delineated 19,000 solar arrays, covering an area of 0.8 sqkm, and extracted 75.08 sqkm of suitable rooftops for future installations. The analysis revealed, current solar infrastructure generates 141.42 GWh electricity, satisfying 6.34 % of Islamabad's annual energy demand. Utilizing 50 % rooftop area could generate 6578 GWh annually, meeting 294 % of the city's electricity needs. This research contributes to the strategic planning for solar energy infrastructure, demonstrating the substantial role rooftop solar can play in meeting urban energy needs. This can inform policy decisions and guide investment opportunities for expanding clean energy in the city.

Using Urban Building Energy Models for the Development of Sustainable Island Energy Systems

This study evaluates the use of City Energy Analyst, an urban building energy modelling tool, to design zero-carbon energy communities in low-industry isolated island settings. The research aims to test the effectiveness of the software during the development of sustainable energy systems in isolated microgrids and compares it with the widely used tool EnergyPLAN. The goal of the study focused on making a community self-sustainable, considering the rooftop area available in the populated settlements to install photovoltaic systems and distributed storage capacity. With this purpose in mind, the evaluated tool estimated the energy consumption of each building and the respective total annual consumption of Corvo Island, a location that is naturally isolated and dependent on fossil fuels. The results demonstrated that City Energy Analyst is an innovative tool to estimate energy consumption and potential energy generation of photovoltaic systems in a remote location, providing additional features to a traditional model and motivating further development of the associated plug-in. However, it requires initial time-consuming efforts to build a reliable model. As a complement, EnergyPLAN can be used to enhance the design, with the integration of the local existing and potential generation sources and to confirm the stability of the overall energy system. This tool introduced additional wind capacity and centralized storage into the model, testing the balance of the system. Therefore, the study proposes a framework combining the strengths of both tools to measure island energy systems, as they can complement each other, to build a strong analysis model.

Evaluating rooftop rainwater harvesting potential to satisfy urban water demand in Hosaena City, South Central Ethiopia

ABSTRACT The assessment of the rainwater harvesting (RWH) potential in Hosaena City from medium to large public buildings is the main objective of the study. ArcGIS with Google Earth Pro was used to calculate the rooftop area of the selected building, and RWH from each category of public buildings was evaluated by considering rooftop areas, monthly rainfall, and runoff coefficient. The result shows that the highest amount of rainwater was harvested from the City Administration building in August (197.1 m3), whereas the lowest was collected from the Health Center building in December (1.8 m3). Additionally, the contribution of RWH from individual public buildings for each month was evaluated, and its values ranged from 0.073 to 1.8%. The comparison shows that Wachemo University, Nigist Eleni Comprehensive Hospital, a technical and vocational institute, and teacher training center buildings, could have a significant potential for rainwater storage, ranging from 1.56 to 28.41%. This implies that, besides saving a noteworthy volume of potable water, the excess rainwater can be stored and utilized for the later dry months. As a result, it is recommended that rooftop RWH in Hosaena be the best source of the city's water supply system to reduce the current water supply shortage.

Application of Satellite Data for Estimating Rooftop Solar Photovoltaic Potential

Rooftop solar photovoltaics can significantly contribute to global energy transitions by providing clean, decentralized energy without the need for new land, thereby avoiding land-use conflicts. It serves as a valuable complement to other renewable-energy sources and is expected to play a crucial role in future electricity systems. Due to the spatiotemporal variability in the solar radiation on roof surfaces, it is essential to determine the potentials of the rooftop photovoltaics and its variations in specific regions. In Germany, this potential was assessed in 5 km × 5 km zones, as well as at the federal-state and national levels. High-quality satellite and reanalysis data were used to determine the power output of the solar photovoltaics. Additionally, high-resolution (2 m × 2 m) European Settlement Map data, calibrated with solar cadastre data, were utilized to evaluate different scenarios. The results show that the potential is concentrated in larger urban areas and the southwestern part of Germany due to the availability of rooftop space and solar radiation. Overall, the national rooftop areas are substantial across all scenarios, ranging from 2100 to 4500 km2. The applied methods and scenarios provide a straightforward way to reveal the spatiotemporal variability and define realistic ranges of the solar photovoltaic potential without requiring detailed information about each building. However, assessing the rooftop photovoltaic potential remains challenging and uncertain due to the lack of large-scale, high-resolution data on building characteristics and the complexity of the solar radiation distribution in urban environments.

Global high-resolution growth projections dataset for rooftop area consistent with the shared socioeconomic pathways, 2020–2050

Assessment of current and future growth in the global rooftop area is important for understanding and planning for a robust and sustainable decentralised energy system. These estimates are also important for urban planning studies and designing sustainable cities thereby forwarding the ethos of the Sustainable Development Goals 7 (clean energy), 11 (sustainable cities), 13 (climate action) and 15 (life on land). Here, we develop a machine learning framework that trains on big data containing ~700 million open-source building footprints, global land cover, road, and population datasets to generate globally harmonised estimates of growth in rooftop area for five different future growth narratives covered by Shared Socioeconomic Pathways. The dataset provides estimates for ~3.5 million fishnet tiles of 1/8 degree spatial resolution with data on gross rooftop area for five growth narratives covering years 2020–2050 in decadal time steps. This single harmonised global dataset can be used for climate change, energy transition, biodiversity, urban planning, and disaster risk management studies covering continental to conurbation geospatial levels.

Multi-Scenario analysis of rooftop greening regulation on runoff effects based on adaptive Evaluation: A case study of Macau, China

The reduction in internal ecological spaces within urban environments and the expansion of impervious surfaces have been identified as factors significantly increasing the susceptibility of cities to flood disasters. Rooftop greening, an essential component of urban stormwater management strategies, offers a versatile solution for augmenting permeable surfaces and delivering ecological services while seamlessly integrating with existing urban infrastructure. This approach has been proven effective in enhancing urban resilience against rainfall-induced flooding events. Hence, the precise identification of suitable building rooftops for green infrastructure within urbanized regions, combined with the simulation of runoff regulation effects brought about by these rooftop greening interventions, holds substantial practical significance. This study innovatively constructs a technical method for measuring the runoff control performance of urban-scale green roofs from identification, evaluation to simulation. Taking the Macao Special Administrative Region as an example, a green roof suitability evaluation index system that is consistent with urban characteristics has been constructed, integrating machine learning, comprehensive evaluation, SWMM simulation methods to evaluate the suitability of roof greening in urban areas and simulate the impact of multi-senarios green roof construction types on runoff regulation. Finally, a comprehensive strategy for rooftop greening construction in Macau is proposed, with the aim of amplifying the runoff regulation capabilities of such initiatives. The main findings of the research include the following: (1) The research area exhibits a notably high aggregate potential for rooftop greening, with suitable rooftop areas comprising approximately 34% of the total rooftop expanse. Notably, construction vintage and roof elevation are identified as the most substantive constraints on rooftop greening. (2) Discernible differences in rooftop greening construction scale exert a significant influence on runoff regulation capacity, with the magnitude of greening positively correlated with its runoff regulation efficacy. Distinct greening typologies elicit varying impacts on runoff regulation, with semi-intensive rooftop greening surpassing extensive approaches in runoff regulation performance. Disparate distribution patterns of rooftop greening engender dissimilar runoff regulation effects, with rooftop greening layouts situated distant from drainage outlets facilitating runoff mitigation, while those in close proximity to drainage outlets enhance peak flow reduction effects.

Multicriteria solar photovoltaic potential evaluation for high educational buildings. Case study of Polytechnic University of Valencia, Spain

Solar PV technologies have been expanding rapidly, and the installed power has increased, especially in the last decade. Their inclusion in university buildings arises as a key factor for sustainable transition in cities, since they have an important potential as case studies for urban experimentation positive effects on students and other stakeholders. This paper proposes a method to determine the availability for installing solar PV in universities' rooftops, considering simulation and cartography data, together with a final experimental validation stage. Unavailable areas for each rooftop are determined, including obstacles, the inner use of the rooftop and shadowed areas. Finally, the method verifies the technical suitability for all the proposed scenarios and applies an economic-environmental multicriteria evaluation to select the most suitable one. The methodology is validated in the Universitat Politècnica de València Vera-Campus. In total, 88913 m2 of the rooftops are suitable for solar PV incorporation, representing 48 % of the total surface. 52 % of the solar PV installable capacity takes place in surfaces which can incorporate more than 100 kW, 20.6 % between 50 and 100 kW and 27.4 % less than 50 kW. Finally, the multicriteria evaluation proved that the scenario with all the possible installations is the most suitable one.

Massive Solar PV Potential in Sri Lanka

Sri Lanka is facing an energy crisis due to insufficient exploitation of renewable energy resources and high reliance on imported fossil fuels. Building-integrated PV (BIPV) systems are one approach that provides various benefits in countries with limited land areas and congested metropolitan regions for ensuring energy security. This study was conducted to evaluate the rooftop solar PV capacity and yearly electricity generation potential in selected provinces in Sri Lanka. The study found 115 km2 of rooftop area for solar PV installation in four Sri Lankan provinces; Sabaragamuwa, Western, Northern, and North Central with approximately 25 GW of solar PV installation capacity could lead to annual electricity generation of 45 TWh which could reduce carbon emissions by 20 million tCO 2 per year.

Estimation of Roof Top Rain Water Harvesting Potential: A Proposed Solution to Water Scarcity in Shrigonda Town, Maharashtra, India

The burning issue in cities will be water scarcity in the coming years. The world population in cities has increased from 29.6 percent to 56.2 percent and is predicted to reach 68.4 percent by 2050. Therefore, this study has attempted to find a solution to tackle the urban water scarcity issue. Recently, rainwater harvesting has emerged as a sustainable and effective system for water conservation in urban areas. Hence, the ward-wise rooftop area was calculated and the rooftop rainwater harvesting potential was estimated by applying the Gould & Nissen, formula for Shrigonda Town. The result reveals that the total water demand in the water stress period was 41,34,41,010 litres while the total rainwater harvesting potential was 39,07,42,128 litres, which means about 94.51 % of the total demand will be met after the rooftop rainwater harvesting system is installed. The study concludes that rooftop rainwater harvesting is considered a sustainable and best alternative tool to tackle urban water scarcity.

A GIS-based approach to determine the priority area for rainwater harvest in Kupang

Kupang, a pivotal economic and administrative hub in Nusa Tenggara Timur, Indonesia, faces recurring droughts resulting in crop failures, food insecurity, and health problems. Addressing this water crisis entails rainwater harvesting as a potential solution. This study establishes a comprehensive framework for prioritizing rainwater harvesting areas in Kupang. Using the weighted overlay method and open-source GIS software, our approach involves three stages: identifying drought and flood priority zones, defining suitability indicators, and quantifying the potential of rainwater harvesting systems. By leveraging climatological, geological, and hydrological information, we determine priority areas for drought and flood management. Our analysis of rainwater harvesting suitability integrates climatological information, land use and land cover mapping, runoff potential assessment, and water use index. Quantification of rainwater harvesting system requirements hinges on rooftop area and population data. The entire wards in Kupang are classified as high priorities for drought mitigation. Therefore, rainwater harvesting is a viable strategy for all wards. The most prioritized and in-demand wards, Oesapa, Sikumana, Lasiana, and Liliba, have the potential to install a minimum of 12,000 rainwater harvesting systems, each with a 1500-liter volume barrel.

INTERNET OF THINGS-BASED AIR QUALITY ANALYSIS FOR MONITORING CO2 CONCENTRATION IN ROOFTOP BUILDING AREAS

This research aims to comprehend the air quality in rooftop areas in the city of DKI Jakarta, renowned for its high population density and rapid infrastructure development. The main focus is on the concentration of carbon dioxide (CO2) in the roof area, serving as an indicator of air quality influenced by air pollution, industrial activity, and heavy transportation. The utilization of Internet of Things (IoT) technology and CO2 sensors proves to be an effective solution for real-time monitoring of CO2 concentrations. This research holds significance for air pollution control measures, providing insight into the impact of rooftop gardens in reducing CO2 emissions and inspiring future research in the realms of air quality and IoT technology. Through prior literature, three notable studies underscore the industrial and technological impact of CO2 monitoring. The research was conducted in two locations in DKI Jakarta, namely the Garden Roof and Ordinary Roof areas. Monitoring took place over four parts of the day with a four-hour interval to compare CO2 levels. The tools employed included the NodeMCU ESP8266, DHT-22 sensor, and MQ-135 sensor. Results revealed that roof areas with gardens exhibited lower average CO2 levels (295 PPM) compared to regular roofs (360 PPM), indicating the potential of garden roof designs to reduce CO2 concentrations. Research recommendations include increasing the frequency of data collection and considering additional factors for a more comprehensive understanding of urban air quality.

Building a Better Roadmap toward a Green Economy through Advanced Rooftop Solar Mapping and Enhanced Energy Yield

Objective: This study aims to develop a transparent roadmap for the implementation of rooftop solar (RTS) systems to boost solar energy adoption, addressing the lack of a definitive solar roadmap. The objective is to utilize Helioscope solar software to envision the maximum shadow-free area over building rooftops and simulate energy generation potential using fixed tilt-based and monthly optimum tilt-angle control-based solar photovoltaics systems. Methods: The research employs HelioScope software to estimate shadow-free rooftop areas of government buildings in an Indian state, considering both fixed-tilt and optimum tilt angle control-based solar tracking systems. The study validates monthly optimum tilt angles for different districts and presents an experimental setup with a 2kWp RTS system. Results: The district-wise analysis reveals the useful rooftop area and energy generation potential, indicating an increase in annual solar energy yield with the implementation of an optimum tilt angle control-based tracking system. The results suggest that chronological implementation based on available rooftop area can aid in achieving the mandated RTS target. Conclusion: The proposed methodology provides a guideline for developing a transparent RTS installation roadmap. The study highlights the potential of an 8% increase in annual solar energy yield by incorporating monthly optimum tilt angle control. The district-wise spatial differences in solar energy production serve as a prototype for other states and countries, facilitating effective solar mapping and policy planning for RTS installations.

Application of Green Technologies to Reduce Impacts of Urban Non-Point Sources Pollution

Storm water runoff from different types of urban catchments and discharge from LID system applied in urban catchments were monitored since 2009 to 2017 in Kongju National University. The performance of green technology (GI) system was evaluated to mitigate the problem like pollutant treatment and restore natural hydrological cycle. The result showed that the urban catchments were sources of pollutants like sediments, organics, nutrients and heavy metals. Thus, the concentrations of these pollutants are highly dependent on the antecedent dry days and types of catchments. Since, roads and parking lots observed higher concentration of sediment and organics however heavy metals were highly contributed by the rooftop areas. Moreover, the application of green technologies could be a better solution to mitigate the problems associated with urbanization. Similarly, GI technology were highly significant to reduce runoff generated and can restore natural hydrological cycle. Lastly, the pollutant removal efficiency of different system was significant due to application of different media and plants.