Sustainable Urban Environment through Green Roofs: A Literature Review with Case Studies

This study conducts a literature review coupled with case-study calculations comparing the thermal contribution of semi-intensive and intensive (deeper) green roofs to non-insulated and insulated building roofs, and enhancing comprehension by validating applied scenarios with published literature-based data. Mitigation of the urban heat island is crucial for reducing energy consumption and enhancing urban sustainability, especially through natural solutions such as green (i.e., planted) roofs. The energy and environmental benefits of green roofs include energy conservation, thermal comfort, noise reduction, and aesthetic improvement. Legal mandates, innovative business models, financial subsidies and incentives, regulations, etc. are all components of green roof policies. Conflicts between private property owners and the public, regulatory gaps, and high installation costs are among the challenges. Green roofs are layered and incorporate interacting thermal processes. Green roof models are either based on the calculation of thermal transmittance (U-values), an experimental energy balance, or data-driven (primarily neural network) approaches. U-values were calculated for eight hypothetical scenarios consisting of four non-insulated and four insulated roofs, with or without semi-intensive and intensive green roofs of various materials and layer thicknesses. While the non-planted, non-insulated roof had the highest U-value, planted roofs were particularly effective for non-insulated roofs. Three of these scenarios were in reasonable accord with experimental and theoretical thermal transmittance literature values. Finally, a non-insulated planted roof, particularly one with rockwool, was found to provide a certain degree of thermal insulation in comparison to a non-planted insulated roof

Financial crisis and energy consumption: A household survey in Greece

Δημοσίευση σε επιστημονικό περιοδικόSummarization: This research aims to investigate, analyze and characterize the relation between the economic crisis and energy consumption in Greece. A survey held in the spring and summer of 2012 collected data of the heating energy consumption for 2010–2011 and 2011–2012, from 598 households via a questionnaire. Comparing the 2010–11 winter to the harsher winter of 2011–12 showed that inhabitants consumed less energy during the winter of 2011–12 because of the rapid economic degradation. Important conclusions were drawn regarding the energy consumption of the households which during the harsh winter 2011–12 was 37% less than expected. Cluster analysis rendered two distinct clusters: three fourths of the households belonged to the lower income group that lived in a smaller space, had half the income and consumed more specific energy compared to the high income group, although much less than expected based on the degree hours of the second winter. One out of three higher-income and one out of four lower-income households adopted some conservation measures after the first winter while 2% of the higher income households and 14% of the lower-income households were below the fuel poverty threshold. Directions for further research include monitoring of low income households with sensors.Παρουσιάστηκε στο: Energy and Building