Carlo Cecere - Academia.edu (original) (raw)

Papers by Carlo Cecere

Riflessioni progettuali sulle identità possibili di Roma elaborate nel workshop internazionale di... more Riflessioni progettuali sulle identità possibili di Roma elaborate nel workshop internazionale di progettazione organizzato dal DAC dell'Universita di Roma "La Sapienza" e da ISVEU

The relationship between morphology, climate and energy has always influenced deeply the developm... more The relationship between morphology, climate and energy has always influenced deeply the development of urban settlements. In the Mediterranean context, this process led to compact and dense urban textures, made of highly inertial materials and cladded with bright colors in order to prevent overheating and thermal discomfort. Nowadays, cooling and heating systems relieves the architectural design from climatic constraints. However this has resulted in increased energy consumption, especially in the summer season because of the widespread use of air conditioning systems. The problem is worsened by the Urban Heat Island (UHI) effect. Shape and geometry of a city affect its climate, and so the energy demand at the urban scale (Ratti 2003, Morganti 2012). The proportions of the urban canyon (height/width ratio) can produce multiple reflections of solar radiation. In addition, the cooling process is decreased during the night due to the low values of the sky view factor (Oke, 2012). Therefore, in a dense and compact urban texture, higher temperatures can occur especially during the night. The present study seeks to highlight the effect of urban morphology on the UHI intensity in the Mediterranean context. Several morphologically homogeneous textures of Rome and Barcelona are parametrically modelled and compared, by means of the Urban Weather generator tool (Bueno, 2012). The results show that air temperature substantially varies according to different urban morphologies. Understanding the microclimatic behavior of most recurrent urban textures can steer energy and retrofitting policies at urban scale and help to achieve the energy goals set by E.U.

Sustainability

Nowadays, energy retrofit interventions on the existing building stock are of paramount importanc... more Nowadays, energy retrofit interventions on the existing building stock are of paramount importance towards energy consumption and emissions reductions in the construction sector. Such interventions are also crucial in the view of increasing cities resilience with respect to the intensification of frequent extreme weather events, such as cold spells and heatwaves. Indeed, a wide portion of our cities is dated and lacking with respect to performances. These are the motivations behind the proposed sustainable approach, which deals with the environmental perspective, but also with social and economic ones, by proposing the retrofit of the Public Residential Building stock (Edilizia Residenziale Pubblica, ERP). The objective is to improve the energy performance of ERP stock by means of construction materials coming from local km0 agricultural waste and by-products. The research was conducted by means of in field and numerical analyses of the energy performances of a relevant case study b...

Ace Architecture City and Environment, 2012

Science of The Total Environment

Rivista Tema

In the current scenario where urban areas are exposed to extreme climate phenomena, resilience of... more In the current scenario where urban areas are exposed to extreme climate phenomena, resilience of cities and buildings becomes fundamental. Thus, not only defensive, traditional actions, but also alternative solutions towards resilience need to be implemented. Amphibious and floating houses, still not investigated in literature, allow the building to adapt to water presence due to their specific construction and technical properties. Here, we consider such buildings’ typologies under the construction and thermal-energy performance lenses, by means of yearly dynamic energy simulations.

The International Journal of the Constructed Environment

Journal of Physics: Conference Series

Energy Procedia

Within the variation of energy performance at urban scale, the relation between solar irradiation... more Within the variation of energy performance at urban scale, the relation between solar irradiation and urban form takes a central role. The solar availability on façades which is influenced by the morphology of the urban context, is strictly related to building energy performance indeed. In this paper, we aim at identifying a set of urban morphology indicators (UMIs) that show the most accurate relations with the solar availability on façades (SI y) in the Mediterranean context. The analysis that relates to 14 urban textures of Rome and Barcelona comprises seven UMIs: gross space index, floor space index, façade-to-site ratio, average building height, volume-area ratio, building aspect ratio and sky factor of building façades. The SI y in each texture has been calculated with Heliodon2 software, using normalised models; the relation between SI y and UMIs were investigated using least-square regression analysis. Results suggest that gross space index, façade-to-site ratio and sky factor show very good correlation with SI y (R 2 = 0,91) and could be used to develop a comparative assessment tool of solar performance at fabric scale. This could ease the work of urban planners and architects in the early stage of design, reducing both data and time normally needed to perform solar analyses at urban scale.

Buildings

Energy efficiency of building heritage derived from pre-regulation period is one of the most deba... more Energy efficiency of building heritage derived from pre-regulation period is one of the most debated topics in Europe. Building façades, through opaque walls and thermal bridges, are a major source of transmission heat losses and require sustainable and consistent solutions. Aiming to achieve an energy demand reduction, thermal features of building façades were evaluated by field measurements and simulations for one INA-Casa listed apartment building built in the 1950s. Non-destructive insulating solutions have been proposed and a comparison between transmission heat loss coefficient in the current situation and the designed intervention was made. Results show that before the renovation, opaque walls and thermal bridges respectively contributed to 25% and 44% of total transmission heat loss in the case-study building façade. After the renovation, total impact was reduced up to 70% depending on whether high performance windows were replaced; in particular, the impact of opaque walls and thermal bridges were reduced by 66% and 82%, respectively. Interventions performed primarily on the internal layer of the façade with insulation elements, when appropriately designed, strengthen the negative effects of thermal bridges in junctions. Findings show that an accurate insulation design allows for both more efficient conditions and the preservation of the heritage-listed buildings.

ACE: Architecture, City and Environment

The lack of urban-specific climate data is, today, one of the major limits for an accurate estima... more The lack of urban-specific climate data is, today, one of the major limits for an accurate estimation of the building energy performance in the urban context. The urban climate is substantially modified by the "heat island" effect that determines an increase of the air temperature compared to the surrounding rural areas. By contrast, the weather data used to run the energy simulations normally refer to rural or suburban weather stations, causing relevant errors in the energy assessment, especially in hot climates. This study aims at evaluating the accuracy of the "Urban Weather Generator" (UWG), a model developed for generating urban weather files from rural weather data in order to improve the accuracy of the building energy simulations in the urban context. To this purpose, the model predictions have been compared to actual observations in different urban sites in Rome and Barcelona. The comparisons have been conducted for one year of observations for each site, focusing the analysis on summer and winter months. The model accuracy has been assessed through statistical analysis of the average error. Results show that the UWG model is able to capture the general trend of the urban temperature. The accuracy of the prediction increases for urban sites located in a rather homogeneous urban fabric in terms of building density and vegetation coverage. In these situations, the model allows a good prediction of the urban air temperatures with low computational requirement and it can be a useful tool to improve the accuracy of urban energy analysis.

Procedia Environmental Sciences, 2017

22Nd Isuf Conference City As Organism New Visions For Urban Life, Feb 15, 2015

The combined effects of urban heat island (UHI), urban population growth and energy overexploitat... more The combined effects of urban heat island (UHI), urban population growth and energy overexploitation are undermining the safety of urban areas. Urban morphology plays a prominent role in this context, because it affects building's energy demand and local climate at urban scale. However, this contribution is recurrently neglected. The present contribution seeks to investigate the direct and indirect effect of urban morphology on buildings energy performance in the Mediterranean climate. Urban morphology affects energy demand by modifying two relevant variables: outdoor air temperatures and incident radiation. The relevance of these effects were studied on a sample of urban textures of Rome and Barcelona. The study is parametric in approach. The textures were modelled and parameterized and their performances were compared. The UHI in different urban textures was calculated, by Urban Weather Generator tool. Then a sensitivity analysis of the building energy demand to the outdoor air temperatures and the incoming solar radiation was carried out, by EnergyPlus engine. Results confirm the relevance of urban morphology to the UHI intensity. Warmer temperatures lead to an average increase of energy demand from 10% to 35%, according to different urban densities. At the same time, the incident radiation reduction due to urban obstruction is desirable in Mediterranean climate; it allows a reduction of annual energy demand up to the 19% compared to an unobstructed environment. Therefore, relevant errors may occur if urban morphology's contribution to energy demand is neglected, approximately 89% for space heating and 131% for space cooling calculations, depending on the texture density and the building orientation.

The Urban Heat Island (UHI) effect is particularly concerning in Mediterranean zone, as climate c... more The Urban Heat Island (UHI) effect is particularly concerning in Mediterranean zone, as climate change and UHI scenarios foresee a fast growth of energy consumption for next years, due to the widespread of air conditioning systems and the increase of cooling demand. The UHI intensity is thus a key variable for the prediction of energy needs in urban areas. This study investigates the intensity of UHI in Barcelona (Spain), the densest Mediterranean coastal city, and its impact on cooling demand of residential buildings. The experimental analysis is based on temperature data from rural and urban Weather Stations and field measurements at street level. The maximum average UHI intensity is found to be 2.8 ◦C in winter and 1.7 ◦C in summer, reaching 4.3 ◦C at street level. Simulations performed with EnergyPlus indicate that the UHI intensity increases the sensible cooling load of residential buildings by around 18%–28%, depending on UHI intensity, amount of solar gains and cooling set point. In the light of the results, the UHI intensity in Mediterranean context should be properly considered
in performing energy evaluations for urban contexts, since standard meteorological data from airport weather stations are not found to be accurate enoug.