scholarly journals Experimental Evaluation and Numerical Simulation of the Thermal Performance of a Green Roof

2020 ◽  
Vol 10 (5) ◽  
pp. 1767 ◽  
Author(s):  
Claudia Guattari ◽  
Luca Evangelisti ◽  
Francesco Asdrubali ◽  
Roberto De Lieto Vollaro
Keyword(s):  
Energy Savings ◽  
Thermal Inertia ◽  
Green Roofs ◽  
Energy Performance ◽  
High Energy ◽  
Active Systems ◽  
Building Models ◽  
Collateral Effect ◽  
Building Components ◽  
Energy Simulations

In the building sector, both passive and active systems are essential for achieving a high-energy performance. Considering passive solutions, green roofs represent a sustainable answer, allowing buildings to reach energy savings, and also reducing the collateral effect of the Urban Heat Island (UHI) phenomenon. In this study, a roof-lawn system was investigated by means of an extended measurement campaign, monitoring the heat transfer across the roof. Heat-flow meters and air- and surface-temperature probes were applied in a real building, in order to compare the performance of the roof-lawn system with a conventional roof. This experimental approach was followed to quantify the different thermal behaviors of the building components. Moreover, an equivalent thermal model of the roof-lawn system was studied, in order to obtain the equivalent thermal properties of the roof, useful for setting building models for yearly energy simulations. The roof-lawn system revealed its advantages, showing a higher thermal inertia with no overheating in summertime and a lower thermal transmittance with energy savings in wintertime, and, consequently, better indoor conditions for the occupants of the building.

scholarly journals On the Energy Performance of an Innovative Green Roof in the Mediterranean Climate

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5163
Author(s):  
Luca Evangelisti ◽  
Claudia Guattari ◽  
Gianluca Grazieschi ◽  
Marta Roncone ◽  
Francesco Asdrubali
Keyword(s):  
Urban Areas ◽  
Energy Savings ◽  
Thermal Inertia ◽  
Thermal Conditions ◽  
Noise Pollution ◽  
Green Roofs ◽  
Energy Performance ◽  
Thermal Insulating ◽  
Heating And Cooling ◽  
High Thermal Inertia

Green roofs have a thermal insulating effect known since ancient times. In the building sector, green roofs represent a sustainable passive solution to obtain energy savings, both during winter and summer. Moreover, they are a natural barrier against noise pollution, reducing sound reflections, and they contribute to clean air and biodiversity in urban areas. In this research, a roof-lawn system was studied through a long experimental campaign. Heat-flow meters, air and surface temperature sensors were used in two buildings characterized by different surrounding conditions, geometries and orientations. In both case studies, the thermal behaviors of the roof-lawn system were compared with the conventional roofs. In addition, a dynamic simulation model was created in order to quantify the effect of this green system on the heating and cooling energy demands. The roof-lawn showed a high thermal inertia, with no overheating during summer, and a high insulating capacity, involving energy savings during winter, and consequently better indoor thermal conditions.

scholarly journals Impact of a building shape factor on space cooling energy performance in the green roof concept implementation

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 687-698 ◽  
Author(s):  
Marija Stamenkovic ◽  
Mirjana Miletic ◽  
Saja Kosanovic ◽  
Goran Vuckovic ◽  
Srdjan Glisovic
Keyword(s):  
Shape Factor ◽  
Energy Savings ◽  
Green Roof ◽  
Green Roofs ◽  
Energy Performance ◽  
Environmental Benefits ◽  
Existing Buildings ◽  
Building Shape ◽  
Building Models ◽  
Space Cooling

The reduction of energy demand for space cooling requires adequate solutions at building and built environment scales in order to achieve sustainability goals. Since many existing buildings have inadequate envelopes for reducing heat gains in summer and heat losses in winter, environmentally friendly renovation techniques have to be considered. The roofs of existing buildings were identified as a field of intervention which could contribute to providing both energy savings and environmental benefits. The aim of the paper was to evaluate the contribution of green roofs to energy savings for space cooling depending on the building shape factor. Two groups of building models, with vertical and horizontal expansions, were analysed. The comparative analyses of the building models with conventional and green roofs showed small reduction of energy consumption less than 1% in case of well-insulated roofs with the addition of the extensive green roof. The comparison of different building models with green roofs of the same volume, which is in this case the same cooling area, indicated a more effective solution for green roofs implementation with the aim to improve energy performances of existing buildings using this passive design technique.

scholarly journals Benchmarking of energy consumption in municipal wastewater treatment plants – a survey of over 200 plants in Italy

2018 ◽  
Vol 77 (9) ◽  
pp. 2242-2252 ◽  
Author(s):  
M. Vaccari ◽  
P. Foladori ◽  
S. Nembrini ◽  
F. Vitali
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Municipal Wastewater ◽  
Energy Savings ◽  
Wastewater Treatment Plants ◽  
Specific Energy Consumption ◽  
Oxygen Demand ◽  
Energy Performance ◽  
High Energy ◽  
Municipal Wastewater Treatment

Abstract One of the largest surveys in Europe about energy consumption in Italian wastewater treatment plants (WWTPs) is presented, based on 241 WWTPs and a total population equivalent (PE) of more than 9,000,000 PE. The study contributes towards standardised resilient data and benchmarking and to identify potentials for energy savings. In the energy benchmark, three indicators were used: specific energy consumption expressed per population equivalents (kWh PE−1 year−1), per cubic meter (kWh/m3), and per unit of chemical oxygen demand (COD) removed (kWh/kgCOD). The indicator kWh/m3, even though widely applied, resulted in a biased benchmark, because highly influenced by stormwater and infiltrations. Plants with combined networks (often used in Europe) showed an apparent better energy performance. Conversely, the indicator kWh PE−1 year−1 resulted in a more meaningful definition of a benchmark. High energy efficiency was associated with: (i) large capacity of the plant, (ii) higher COD concentration in wastewater, (iii) separate sewer systems, (iv) capacity utilisation over 80%, and (v) high organic loads, but without overloading. The 25th percentile was proposed as a benchmark for four size classes: 23 kWh PE−1 y−1 for large plants > 100,000 PE; 42 kWh PE−1 y−1 for capacity 10,000 < PE < 100,000, 48 kWh PE−1 y−1 for capacity 2,000 < PE < 10,000 and 76 kWh PE−1 y−1 for small plants < 2,000 PE.

scholarly journals Review on the HVAC System Modeling Types and the Shortcomings of Their Application

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Raad Z. Homod
Keyword(s):  
Large Scale ◽  
Energy Savings ◽  
Thermal Sensation ◽  
System Modeling ◽  
Thermal Inertia ◽  
Hvac System ◽  
Advantages And Disadvantages ◽  
Building Models ◽  
Hvac System Modeling ◽  
High Thermal Inertia

The modeling of the heating, ventilation, and air conditioning (HVAC) system is a prominent topic because of its relationship with energy savings and environmental, economical, and technological issues. The modeling of the HVAC system is concerned with the indoor thermal sensation, which is related to the modeling of building, air handling unit (AHU) equipments, and indoor thermal processes. Until now, many HVAC system modeling approaches are made available, and the techniques have become quite mature. But there are some shortcomings in application and integration methods for the different types of the HVAC model. The application and integration processes will act to accumulate the defective characteristics for both AHU equipments and building models such as nonlinear, pure lag time, high thermal inertia, uncertain disturbance factors, large-scale systems, and constraints. This paper shows types of the HVAC model and the advantages and disadvantages for each application of them, and it finds out that the gray-box type is the best one to represent the indoor thermal comfort. But its application fails at the integration method where its response deviated to unreal behavior.

scholarly journals Urban Overheating Impact: A Case Study on Building Energy Performance

2021 ◽  
Vol 11 (18) ◽  
pp. 8327
Author(s):  
Gabriele Battista ◽  
Marta Roncone ◽  
Emanuele de Lieto Vollaro
Keyword(s):  
Energy Savings ◽  
Meteorological Data ◽  
Building Energy ◽  
Energy Performance ◽  
Climatic Conditions ◽  
Building Energy Performance ◽  
Suburban Areas ◽  
Energy Needs ◽  
Energy Scenario ◽  
Energy Simulations

It is well known that the construction sector is one of the main sectors responsible for energy consumption in the current global energy scenario. Thus, buildings’ energy software become essential tools for achieving energy savings. Climate and its implications for building energy performance are a critical threat. Hence, the aim of this study is to evaluate the climatic conditions in urban and suburban areas of Rome, estimating the incidence of the Urban Heat Island (UHI) phenomenon. To this end, meteorological data obtained from three different areas (two airports and one inside the city) were examined and compared. Then, TRNSYS software was used to create a simple building, in order to assess the impacts of various climatic situations on building energy performance. The study revealed significant percentage differences both in terms of energy needs for heating, from −20.1% to −24.9% when the reference stations are, respectively, Fiumicino and Ciampino, and for cooling, with a wider range, from +48.7% to +87.5% when the reference stations are Ciampino and Fiumicino. Therefore, the study showed the importance of more accurately selecting sets of climate values to be included in energy simulations.

scholarly journals Thermal Analysis of an Industrial Furnace

2016 ◽  
Author(s):  
Mirko Filipponi ◽  
Federico Rossi ◽  
Andrea Presciutti ◽  
Stefania De Ciantis ◽  
Beatrice Castellani ◽  
...  
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Cfd Simulation ◽  
Energy Performance ◽  
High Energy ◽  
Simulation Software ◽  
Pollutant Emissions ◽  
Door Opening ◽  
Temperature And Pressure ◽  
Mechanical Machining

Industries, which are mainly responsible for high energy consumptions, need to invest in research projects in order to develop new managing systems for rational energy use and to tackle the devastating effects of climate change caused by human behavior. The study reported in this paper concerns the forging industry, where the production processes generally start with the heating of the steel in furnaces and continue with other processes, such as heat treatments and mechanical machining. One of the most critical operations, in terms of energy loss, is the opening of the furnace doors for the insertion and extraction operations. During this time, the temperature of the furnaces decreases by hundreds of degrees in a few minutes. Because the dispersed heat needs to be supplied again through the combustion of fuel, increasing the consumption of energy and the pollutant emissions, the evaluation of the amount of the lost energy is crucial for the development of operating or mechanical systems able to contain this dispersion. To perform this study, CFD simulation software was used. Results show that at the door opening, because of temperature and pressure differences between the furnace and the ambient, turbulences are generated. Results also show that the amount of energy lost for an opening of 10 minutes for radiation, convection and conduction is equal to 5606 MJ where convection is the main contributor with 5020 MJ. The model created, after being validated, has been applied to perform other simulations in order to improve the energy performance of the furnace. Results show that a reduction of the opening time of the door allows energy savings and limits pollutant emissions.

scholarly journals Nearly Zero Energy Standard for Non-Residential Buildings with High Energy Demands—An Empirical Case Study Using the State Related Properties of Bavaria

2017 ◽  
Author(s):  
Michael Keltsch ◽  
Werner Lang ◽  
Thomas Auer
Keyword(s):  
Energy Demand ◽  
Energy Savings ◽  
Residential Buildings ◽  
Energy Performance ◽  
High Energy ◽  
Primary Energy ◽  
The State ◽  
Zero Energy ◽  
Primary Energy Demand ◽  
New Buildings

The Energy Performance of Buildings Directive 2010 calls for the Nearly Zero Energy Standard for new buildings from 2021 onwards: Buildings using “almost no energy” are powered by renewable sources or energy produced by the building itself. For residential buildings, this ambitious new standard has already been reached. But for other building types this goal is still far away. The potential of these buildings to meet a Nearly Zero Energy Standard was investigated by analyzing ten case studies representing non-residential buildings with different uses. The analysis shows that the primary characteristics common to critical building types are a dense building context with a very high degree of technical installation (such as hospital, research and laboratory buildings). The large primary energy demand of these types of buildings cannot be compensated by building and property-related energy generation including off-site renewables. If the future Nearly Zero Energy Standard were to be defined with lower requirements because of this, the state related properties of Bavaria suggest that the real potential energy savings available in at least 85% of all new buildings would be insufficiently exploited. Therefore, it would be useful to instead individualize the legal energy verification process for new buildings to distinguish critical building types such as laboratories and hospitals.

scholarly journals Industrial Decarbonization by a New Energy-Baseline Methodology. Case Study

2020 ◽  
Vol 12 (5) ◽  
pp. 1960
Author(s):  
Rosaura Castrillón-Mendoza ◽  
Javier M. Rey-Hernández ◽  
Francisco J. Rey-Martínez
Keyword(s):  
Energy Consumption ◽  
Energy Management ◽  
Energy Efficient ◽  
Energy Savings ◽  
Energy Performance ◽  
High Energy ◽  
Industrial Sector ◽  
Raw Material ◽  
Management Plans ◽  
The Impact

The main target of climate change policies in the majority of industrialized countries is to reduce energy consumption in their facilities, which would reduce the carbon emissions that are generated. Through this idea, energy management plans are developed, energy reduction targets are established, and energy-efficient technologies are applied to achieve high energy savings, which are environmentally compatible. In order to evaluate the impact of their operations and investments, companies promote measures of performance in their energy management plans. An integral part of measuring energy performance is the establishment of energy baselines applicable to the complete facility that provide a basis for evaluating energy efficiency improvements and incorporating energy performance indicators. The implementation of energy management systems in accordance with the requirements of ISO Standard 50001 is a contribution to the aim and strategies for improving cleaner production in industries. This involves an option for the industry to establish energy benchmarks to evaluate performance, predict energy consumption, and align production with the lowest possible consumption of primary and secondary forms of energy. Ultimately, this goal should lead to the manufacturing of cleaner products that are environmentally friendly, energy efficient, and are in accordance with the global environmental targets of cleaner manufacturing. This paper discusses an alternative for establishing energy baselines for the industrial sector in which several products are produced from a single raw material, and we determined the energy consumption of each product and its impact on the overall efficiency of the industry at the same time. The method is applied to the plastic injection process and the result is an energy baseline (EBL) in accordance with the requirements of ISO 50001, which serves as a reference for determining energy savings. The EBL facilitates a reduction in energy consumption and greenhouse gas emissions in sectors such as plastics, a sector which accounts for 15% of Colombia’s manufacturing GDP.

scholarly journals Nearly Zero Energy Standard for Non-Residential Buildings with High Energy Demands—An Empirical Case Study Using the State Related Properties of Bavaria

2017 ◽  
Author(s):  
Michael Keltsch ◽  
Werner Lang ◽  
Thomas Auer
Keyword(s):  
Energy Demand ◽  
Energy Savings ◽  
Residential Buildings ◽  
Energy Performance ◽  
High Energy ◽  
Primary Energy ◽  
The State ◽  
Zero Energy ◽  
Primary Energy Demand ◽  
New Buildings

The Energy Performance of Buildings Directive 2010 calls for the Nearly Zero Energy Standard for new buildings from 2021 onwards: Buildings using “almost no energy” are powered by renewable sources or energy produced by the building itself. For residential buildings, this ambitious new standard has already been reached. But for other building types this goal is still far away. The potential of these buildings to meet a Nearly Zero Energy Standard was investigated by analyzing ten case studies representing non-residential buildings with different uses. The analysis shows that the primary characteristics common to critical building types are a dense building context with a very high degree of technical installation (such as hospital, research and laboratory buildings). The large primary energy demand of these types of buildings cannot be compensated by building and property-related energy generation including off-site renewables. If the future Nearly Zero Energy Standard were to be defined with lower requirements because of this, the state related properties of Bavaria suggest that the real potential energy savings available in at least 85% of all new buildings would be insufficiently exploited. Therefore, it would be useful to instead individualize the legal energy verification process for new buildings to distinguish critical building types such as laboratories and hospitals.

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