scholarly journals The Role of the Extensive Green Roofs on Decreasing Building Energy Consumption in the Mediterranean Climate

2020 ◽  
Vol 12 (1) ◽  
pp. 359 ◽  
Author(s):  
Mario Maiolo ◽  
Behrouz Pirouz ◽  
Roberto Bruno ◽  
Stefania Anna Palermo ◽  
Natale Arcuri ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Mediterranean Climate ◽  
Positive Impact ◽  
Green Roofs ◽  
Building Envelope ◽  
Insulation Layer ◽  
Indoor Temperature ◽  
The Mediterranean ◽  
One Year ◽  
Roof Temperature

Buildings portion in global energy consumption is 40%, and in the building envelope, the roof is a crucial point for improving indoor temperature, especially in the last and second last floors. Studies show that green roofs can be applied to moderate roof temperature and affect the indoor temperature in summer and winter. However, the performance of green roofs depends on several parameters such as climate, irrigation, layer materials, and thickness. In this context, the present research deals with a comprehensive experimental analysis of different thermal impacts of green roofs in summer and winter in a Mediterranean climate. Measurements carried out in one year in three different types of green roofs with different thicknesses, layers, and with and without the insulation layer. The analysis determined the possible period that indoor cooling or heating might be required with and without green roofs and demonstrated the positive impact of green roofs in moderating the roof temperature and temperature fluctuations, which in summer was remarkable. In conclusion, since in the Mediterranean climate, the thermal differences between green roofs and conventional roofs in summer are much higher than winter, it seems that the green roof without an insulation layer would show better performance.

scholarly journals Decreasing Water Footprint of Electricity and Heat by Extensive Green Roofs: Case of Southern Italy

2020 ◽  
Vol 12 (23) ◽  
pp. 10178 ◽  
Author(s):  
Behrouz Pirouz ◽  
Stefania Anna Palermo ◽  
Mario Maiolo ◽  
Natale Arcuri ◽  
Patrizia Piro
Keyword(s):  
Energy Consumption ◽  
Water Consumption ◽  
Experimental Analysis ◽  
Energy Production ◽  
Mediterranean Climate ◽  
Water Footprint ◽  
Green Roof ◽  
Green Roofs ◽  
Air Conditioner ◽  
Roof Temperature

Electrical and energy production have a noticeable water footprint, and buildings′ share of global energy consumption is about 40%. This study presents a comprehensive experimental analysis of different thermal impacts and water consumption of green roofs in a Mediterranean climate. The study aims to investigate the use of water directly for green roofs and reduce the water footprint of energy in summer and winter due to its thermal impacts. The measurements were carried out for an extensive green roof with an area of 55 m2 and a thickness of 22 cm, and direct water consumption by a green roof and direct and indirect water consumption by cooling and heating systems were analyzed. According to the analysis, in summer, the maximum roof temperature on a conventional roof was 72 °C, while under the green roof it was 30.3 °C. In winter, the minimum roof temperature on a conventional roof was −8.6 °C, while under the green roof it was 7.4 °C. These results show that green roofs affect energy consumption in summer and winter, and the corresponding thermal requirements for the building have a water footprint regarding energy production. In summer, the thermal reduction in the water footprint by a green roof was 48 m3 if an evaporative air conditioner is used and 8.9 m3 for a compression air conditioner, whereas the water consumed in the green roof was 8.2 m3. Therefore, using water directly in the green roof would reduce the energy consumption in buildings, and thus less water has to be used in power plants to provide the same thermal impact. In winter, green roofs′ water consumption was higher than the thermal water footprint; however, there is no need to irrigate the green roof as the water consumed comes from precipitation. This experimental analysis determines that in the Mediterranean climate, green roofs allow the achievement of the same thermal conditions for buildings in both summer and winter, with a reduction in water consumption.

scholarly journals Online Implementation of a Soft Actor-Critic Agent to Enhance Indoor Temperature Control and Energy Efficiency in Buildings

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 997
Author(s):  
Davide Coraci ◽  
Silvio Brandi ◽  
Marco Savino Piscitelli ◽  
Alfonso Capozzoli
Keyword(s):  
Energy Consumption ◽  
Temperature Control ◽  
Weather Conditions ◽  
Heating System ◽  
Building Envelope ◽  
Indoor Temperature ◽  
Model Free ◽  
Occupancy Patterns ◽  
Online Implementation ◽  
Indoor Temperature Control

Recently, a growing interest has been observed in HVAC control systems based on Artificial Intelligence, to improve comfort conditions while avoiding unnecessary energy consumption. In this work, a model-free algorithm belonging to the Deep Reinforcement Learning (DRL) class, Soft Actor-Critic, was implemented to control the supply water temperature to radiant terminal units of a heating system serving an office building. The controller was trained online, and a preliminary sensitivity analysis on hyperparameters was performed to assess their influence on the agent performance. The DRL agent with the best performance was compared to a rule-based controller assumed as a baseline during a three-month heating season. The DRL controller outperformed the baseline after two weeks of deployment, with an overall performance improvement related to control of indoor temperature conditions. Moreover, the adaptability of the DRL agent was tested for various control scenarios, simulating changes of external weather conditions, indoor temperature setpoint, building envelope features and occupancy patterns. The agent dynamically deployed, despite a slight increase in energy consumption, led to an improvement of indoor temperature control, reducing the cumulative sum of temperature violations on average for all scenarios by 75% and 48% compared to the baseline and statically deployed agent respectively.

Analysis of Building Envelope Materials Retrofitting of Timber Dwellings Based on Energy Efficiency

2016 ◽  
Vol 723 ◽  
pp. 687-693
Author(s):  
Chun Hua Huang ◽  
Sheng Liu ◽  
Yi Ming Liu
Keyword(s):  
Energy Efficiency ◽  
Payback Period ◽  
Building Envelope ◽  
Energy Simulation ◽  
Simulation Tool ◽  
Insulation Layer ◽  
Architectural Styles ◽  
Western Hunan ◽  
One Year ◽  
Passive Strategy

To find out the optimum building envelope retrofitting methods for timber dwellings in Western Hunan, China, energy efficiency retrofitting strategies of building envelope materials are optimized by an orthogonal test and energy simulation tool, DeST-h. On the premise of protecting their architectural styles, a comprehensive materials retrofitting strategy, a polyurethane foam insulation layer for the double-fir external wall envelope, reed foil for the clay insulation layer roof, using ordinary insulating glass units window material, is provided for the existing timer-structured dwellings in rural area of Western Hunan. After retrofitting, this passive strategy can achieve an energy-saving rate of 64.97%, short 4 years dynamic payback period of investment, and increase by 847h acceptable temperature hours in one year.

scholarly journals Thermal Performance of a Massive Wall in the Mediterranean Climate: Experimental and Analytical Research

2020 ◽  
Vol 10 (13) ◽  
pp. 4611 ◽  
Author(s):  
Chiara Tribuiani ◽  
Luca Tarabelli ◽  
Serena Summa ◽  
Costanzo Di Perna
Keyword(s):  
Mediterranean Climate ◽  
External Surface ◽  
Building Envelope ◽  
Simulation Software ◽  
Thermal Mass ◽  
Cooling Systems ◽  
External Insulation ◽  
Analytical Research ◽  
The Mediterranean ◽  
Italian Territory

In the Mediterranean climate, indoor overheating and, thus, excessive use of cooling systems represents one of the main problems both for the occupants’ health and energy consumption. In order to limit this problem, an appropriate design or energy retrofitting of the building envelope is of utmost importance. The predominance of massive buildings in the Italian territory and the need to comply with Italian regulations often leads technicians to not optimal energy saving solutions. To this purpose, this experimental research was conducted on a mockup building, located in Fabriano and characterized by high thermal mass walls (W0) and two different external insulating systems: Cork based lightweight plaster (W1) and Extruded polystyrene foam panel (XPS) (W2). Furthermore, a virtual model in TRNSYS, a transient simulation software, was used to compare analytical and simulated values. Results show that W2 undergoes a higher level of thermal stress than W1, due to higher peaks in the external surface temperature and larger fluctuations in daily temperature. Therefore, a high value of thermal resistance of the external insulation and low value of external areal heat capacity on a massive building causes external surface overheating problems, thus, not representing the optimal construction solution.

scholarly journals A Comparison of Energy and Thermal Performance of Rooftop Greenhouses and Green Roofs in Mediterranean Climate: A Hygrothermal Assessment in WUFI

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2030
Author(s):  
Mansoureh Gholami ◽  
Alberto Barbaresi ◽  
Patrizia Tassinari ◽  
Marco Bovo ◽  
Daniele Torreggiani
Keyword(s):  
Thermal Performance ◽  
Mediterranean Climate ◽  
Green Roof ◽  
Green Roofs ◽  
Energy Performance ◽  
Building Envelope ◽  
Considerable Proportion ◽  
Urban Context ◽  
Cooling Period ◽  
The Impact

In urban areas, a considerable proportion of energy demand is allocated to buildings. Since rooftops constitute one-fourth of all urban surfaces, an increasing amount of attention is paid to achieving the most efficient shapes and component designs compatible with every climate and urban context, for rooftops of varying sizes. In this study, three types of rooftop technologies, namely insulated, green roof, and rooftop greenhouse, are evaluated for energy and thermal performance using computer simulations. Water surface exposure, absorption, and intrusion are the three important factors in the calculation of hygrothermal models that impact energy consumption and building envelope performance; however, a few studies are specifically focused on providing realistic results in multi-dimensional hygrothermal models and the assessment of the impact of moisture in roofing solutions. This paper aims at evaluating the performance of three different roofing technologies through a two-dimensional hygrothermal simulation in software WUFI. To accomplish this, a precise localized microclimate model of a complex urban context on the scale of a neighborhood was employed to evaluate the cooling and heating loads of the buildings, the impact of the water content in the green roof on the thermal behavior of the roof surface, and the feasibility of designing a building with nearly zero cooling needs. A two-story building in the city center of Bologna, Italy is modelled. Simulation results have shown that during the cooling period, the performance of the designed rooftop greenhouse is the most effective by 50% reduction in cooling loads. Besides, the impact of moisture in green roofs has been detected as a negative factor for thermal and energy performance of the building in the Mediterranean climate. The results ultimately highlighted the capability of passively-designed rooftop greenhouses to create a building with nearly zero cooling needs.

scholarly journals Should You Put Your Energy Into Green Roofs to Reduce Energy Consumption in Your Building

2008 ◽  
Vol 3 (2) ◽  
pp. 26-40 ◽  
Author(s):  
Brad Bass
Keyword(s):  
Energy Consumption ◽  
Urban Areas ◽  
Green Roof ◽  
Green Roofs ◽  
Building Envelope ◽  
Root Penetration ◽  
Environmental Technology ◽  
Drainage Layer ◽  
Growing Medium ◽  
Reduce Energy Consumption

Green roofs are touted as an environmental technology for urban areas due to their many benefits (Lundholm et al. 2008). Although the design and the benefits have been reported in many reports and articles, they are reviewed here for those who are unfamiliar with this technology. Green roofs, or more formally, green roof infrastructure, is a technology that allows for the growth of vegetation on a roof while protecting the building envelope from leakage and root penetration. A green roof is more than a layer of soil piled on the roof, planted in the way that you might plant a garden. The technology consists of multiple layers that include the plants and growing medium or substrate, but also a drainage layer for storing water that was not used by the plants and a waterproof, root-repellent membrane (Figure 1).

scholarly journals Indoor Temperature Improvement and Energy-Saving Renovations in Rural Houses of China’s Cold Region—A Case Study of Shandong Province

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 870 ◽  
Author(s):  
Yanqiu Cui ◽  
Ninghan Sun ◽  
Hongbin Cai ◽  
Simeng Li
Keyword(s):  
Energy Consumption ◽  
Rural Areas ◽  
Building Envelope ◽  
Shandong Province ◽  
Indoor Temperature ◽  
Before And After ◽  
Level Of Economic Development ◽  
Improvement Measures ◽  
Insulation Performance

With the continuous implementation of a plan for reconstruction of “Beautiful Countryside” in China, the rural environment and appearance of rural houses have been significantly improved. However, those houses in cold areas of China have great trouble with indoor temperature and heating-related energy consumption. After investigating the current situation of the layout, building envelope, indoor temperature, and energy consumption of the rural houses renovated by the plan of “Beautiful Countryside” in Shandong Province, this paper puts forward the improvement measures of raising indoor temperature and reducing energy consumption. On this basis, a typical rural house was selected, and DesignBuilder was utilized to simulate the effects before and after the application of different renovation measures for this house. The results show that the main way to raise indoor temperature and reduce energy consumption is to improve the thermal insulation performance of the building envelope, including renovation of the roof, exterior walls, doors and windows, and attached sunspace. In addition, combined with the achievements of “Beautiful Countryside” reconstruction, this paper shall propose specific renovation practices which are suitable for different rural houses. Based on the level of economic development in rural areas, it also puts forward some feasible renovation paths for different rural areas, and further provides references for other areas to carry out relevant work in the future.

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