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

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.

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

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.

Contribution of the species Pilea microphylia in the thermal comfort of a house [Contribución de la especie Pilea microphylia en el confort térmico de una casa]

The research presents the influence of the species Pilea microphylia on the thermal comfort of a house. The dimensions of the test were 2.8 m x 3.8 m x 2.5 m. The measurements were made in two rooms, a room with a roof covered by species Pilea microphylia and another room with a roof no covered. The experimentation was carried out during the months of October and November of 2018. The results show that the room with roof covered with the Pilea microphylia plant improved the thermal comfort of the room in week 5 (temperature of 20.07 °C and relative humidity 75.75%) than with the room with uncovered roof (temperature of 24.94 °C and relative humidity 82.90%). Therefore, it is concluded that the species Pilea microphylia improves the thermal comfort of the room with a temperature variation of 4.87 °C and an attenuation of the relative humidity in 7.15%.

Effect of roof painting of aviaries on thermal comfort, productive performance and physiological variables of broilers chickens

SUMMARY The objective this study was to evaluate the thermal comfort, performance and the physiological variables of 21-42 day of age broiler chickens housed in aviaries with painted and not painted fiber cement roof. A completely randomized design was used in a split-plot design where the plots were composed of the sheds (painted and not painted roof) and the subplots were the evaluation hours (6h00, 9h00, 12h00, 15h00 and 18h00) for a 22-day data collection, considered as the replicates. It was observed that the external painting in white of the roof provided improvements inside the shed for airtemperature (Ta), roof temperature (Tr) and the thermal load of radiation (TLR). The relative humidity (RH) and the Globe-Temperature-Humidity-Index (GTHI) varied only according to the collection times. The exterior painting of the roof had no effect on the physiological variables of the broilers. Productivity performance indexes and financial compensation per lot were better for the roof painted shed. As a result, fiber cement roof painted in white is recommended in aviaries located in hot climates, such as the region in this study.

Base on Real Time Temperature Monitoring and Sprinkler Cooling Control to Achieve Energy Conservation of Air-Conditioning Systems

If the air conditioning usage situation cannot be effectively improved, the energy consumption process will be accelerated, exacerbating the energy crisis. Despite scientists’ efforts to find alternative energy sources to solve the energy crisis, the most immediate solution is to reduce energy consumption.In this study, the energy-conservation system was designed by setting up several temperature sensors, transfer modules, and water sprinklers on rooftops and external walls that were exposed to the most sunlight; the temperature sensor modules regularly measured the roof temperature and used radio frequency (RF) technology to transfer the temperature data to the indoor receiving set. The measured temperatures were then compared with the indoor temperatures, after which the monitor program analysed and sent commands to control and activate the water sprinkler system. This allowed timely sprinkling using the proper water amount to lower the surface temperature of the roofs and external walls, which also slightly reduces the indoor temperature, achieving energy-conservation objective. Actual examples were then used to investigate the energy-saving effectiveness of the proposed system.

Carbon Fiber Reinforced the Cracking Framework Top Side Columns Caused by Roof Temperature Deformation

An example of horizontal cracks on the surface of reinforced concrete side-columns is presented. Based on the finite element analysis , a conclusion is made that those cracks are caused by the frame’s deformation under changing temperature. Then the way to calculate the width of such cracks is raised. The design method for the reparation by sticking carbon fiber materials to the column is also developed. Those methods are applicable in realistic works.

Research of Artificial Sites Green Roof for Energy-Saving Efficiency in Taiwan Taichung

In this study, set the empirical plane pilot area planting the groove (long 425cm × width 300cm × Height 20cm ) in the Taichung City residential area on the second floor roof, planting the groove bottom-up sequence laying frame high-rise, water proof layer, drainage layer,filter layer (non-woven, water-pottery-stone), the medium layer and planting of layer, planting the groove around the hollow brick interval income side to lighten the load. Noon hours exposed roof temperature of 25.49-37.56°C, green roofs surface only at 16.45-24.69°C, 17.74-24.79°C indoor temperature on the second floor, effectively prevent the roof surface temperature rise, and thus reduce the interior roof of the second temperature7.75-12.77°C. Building green roofs to cooling, mainly to reduce the building temperature, reducing air conditioning electricity consumption , accomplish cooling and energy-saving benefits.Compare different annual electricity consumption in the same period, extensive green roof to total electricity consumption of 860 K.Watts/hours , exposed roof to total electricity consumption in 1767 K.Watts/hours, 48.67% of the electricity consumption savings, to achieve energy efficiency.