The Effect of Water Spray Systems on Thermal and Solar Performance of an ETFE Panel for Building Envelope

ETFE membranes are generally used in architecture for large roofing and façade systems, because of their transparency and lightness compared to glass alternatives. Multilayer ETFE panels are used to improve single membrane systems performances, reducing thermal losses, by the use of an air gap between two or more ETFE foils, generally serigraphed or surface treated to reduce solar gains. Surface temperatures and global solar radiation strongly affects mean radiant temperature (MRT), and comfort perceived by a user facing a transparent envelope as well as solar gains strongly influences primary energy use for cooling in summer conditions. In the following paper an alternative dynamic solar gains mitigation strategy is presented and applied to a double layer, non-cushions, ETFE panel for façades. We measured the effectiveness of a water spray system located in the air-gap between the parallel ETFE foils and used to reduce surface temperatures and solar access depending on different summer solar radiation values and outdoor/indoor air temperature conditions. Systems alternative with different in nozzle dimension, water spray geometry and water consumption were already tested to evaluate the best compromise between solar gains reduction and water use. The results are preliminary but we noticed that a reduction up to the 10% of the total solar gains could be achieved as well as a reduction of 10 °C of surface temperature. Comfort evaluation for a standard indoor space were already done

Spectral Light Transmission Measure of Metal Screens for Glass Façades and Assessment of their Shading Potential

Abstract Metal mesh grids and perforated screens are used in new and renovated buildings as an external second skin for the building envelope; to enhance architecture design, to filter daylight and to reduce solar gains. Their effectiveness as shading devices depends on their geometry, texture and application. In the first part of the paper six types of shadings with similar transparencies, depending on geometry and openness factor of metal mesh grid and perforated screen, were investigated. Integrating sphere measurements were collected to obtain spectral optical properties of the shading devices. The optical properties were measured for incidence angles between normal and 60°with a step of 15°. The data collected were integrated to obtain visible and solar transmittance values in accordance with ISO 9050. In the second part of the paper a parametric study on spacing and thread dimension of metal mesh grids was done using Window 6.2 models to evaluate their shading potential, defining annual different shading profiles depending on shading geometry, latitude and orientation. A conventional office unit with a curtain wall facade with a metal mesh grid shading system was modeled in TRNSYS to evaluate the solar gain profiles and their effects on the energy balance of the office unit, under different weather conditions

A Novel Approach to Shape Memory Alloys Applied to Passive Adaptive Shading Systems

A shading device for façade application was developed by combining twisting cylindrical shading elements with the smart use of shape-memory alloy (SMA) components. These allow a dynamic behaviour of a shading device, which does not require electrical motors or manual activation, nor sophisticated electronic controls. The technical development of the system involved research of cylindrical shading geometries, which can transition from straight to hourglass configuration, given a 180° rotation, with limited mechanical movement. This is induced by the stroke of a SMA spring, which functions as both actuator and sensor. Its design is tailored to achieve a passive adaptive component that can be activated under set temperature stimuli, caused by incident solar radiation on a façade. A combination of computer simulations and physical tests were carried out to assess the optimal conditions of the SMA spring activation in a temperate climate condition (Cfa to the Koppen-Geiger classification), correlating transition temperature (50°C), incident solar radiation (>300W/m2 ) and the forces required to operate the cylinders. In parallel, an experimental apparatus was developed to validate the concept on a geometrical point of view, and to ensure its constraints were compatible with a SMA spring control system

Color heterogeneity of building surfaces: lean image processing approach for visible reflectance characterization performance

Daylighting availability and uniformity depend on the interior surface reflectance (). Currently, is obtained through suggested reference values (Illuminating Engineering Society 2012; CIBSE 2015; CIBSE/SLL 2011; CIBSE/SLL 2005), laboratory tests (ASTM E 903 (2012) describes a standardized procedure requiring a calibrated instrument and an as-built surface sample), or by on-site measures (based on luminance and illuminance differences). Novel methodologies compute it by integrating image processing and/or photometry, applied on false colour or HDR images. A simple procedure is needed for accurately assess, even in preliminary design phases, the reflectance of heterogeneous surface areas for new and historical buildings. In fact, heterogeneous surfaces (colour, texture, composition, ageing) difficult the accurate estimation of a representative reflectance value (̅) for building simulation, leading to daylighting performance deviation. This work presents a methodology, based on a per-pixel colour reflectivity () evaluation, to easily acquire an approximate value of the surface visible reflectance (̅). This approach gives a more global ̅ of all surface components, aiming to improve the accuracy of the modelled daylighting analysis. Additionally, the procedure is experimented over a sample reference test room

Experimental Assessment of the Reflection of Solar Radiation from Façades of Tall Buildings to the Pedestrian Level

Urban climates are highly influenced by the ability of built surfaces to reflect solar radiation, and the use of high-albedo materials has been widely investigated as an effective option to mitigate urban overheating. While diffusely solar reflective walls have attracted concerns in the architectural and thermal comfort community, the potential of concave and polished surfaces, such as glass and metal panels, to cause extreme glare and localized thermal stress has been underinvestigated. Furthermore, there is the need for a systematic comparison of the solar concentration at the pedestrian level in front of tall buildings. Herein, we show the findings of an experimental campaign measuring the magnitude of the sunlight reflected by scale models reproducing archetypical tall buildings. Three 1:100 scaled prototypes with different shapes (classic vertical façade, 10% tilted façade, curved concave façade) and different finishing materials (representative of extremes in reflectance properties of building materials) were assessed. A specular surface was assumed as representative of a glazed façade under high-incidence solar angles, while selected light-diffusing materials were considered sufficient proxies for plaster finishing. With a diffusely reflective façade, the incident radiation at the pedestrian level in front of the building did not increase by more than 30% for any geometry. However, with a specular reflective (i.e., mirror-like) flat façade, the incident radiation at the pedestrian level increased by more than 100% and even by more than 300% with curved solar-concentrating geometries. In addition, a tool for the preliminary evaluation of the solar reflectance risk potential of a generic complex building shape is developed and presented. Our findings demonstrate that the solar concentration risk due to mirror-like surfaces in the built environment should be a primary concern in design and urban microclimatology

Metal Mesh as Shading Devices and Thermal Response of an Office Building: Parametric Analysis

Windows are the most important part of the building façade to control solar gains, thermal losses and visual comfort. Office buildings usually have medium-high WWR (window to wall ratio value) and high internal gains (due to users, lighting and appliances). For this reason, they require a good balance between thermal and visible performances of transparent façades and shading control strategies to avoid overheating, optimizing daylighting aspects. A sensitivity analysis was assessed to evaluate primary energy use for heating, lighting and cooling for conventional Italian single office units equipped with static metal mesh shading devices with different geometries and openness factor values. Different location (Milan, Palermo), orientation (south and west) and WWR (33% and 100%) were analyzed. Hence shading devices alternatives as venetian blinds and sun control windows are proposed as a comparison

Development of a High Protein Beverage Based on Amaranth

The objective of this study was to formulate a beverage based on amaranth proteins, stable and nutritious. The process of obtaining the beverage was based on the existing knowledge about starch separation techniques and techno-functional properties of the amaranth proteins. Gums, gellan and xanthan were added to the protein extract and it was heat-treated at 80 °C during 20 min. A beverage with a composition similar to skim cow’s milk was obtained (3.42 ± 0.08; 0.60 ± 0.06; 1.9 ± 0.4; 0.43 ± 0.01; 3 and 90.58 ± 0.01% for proteins, lipids, fiber, ashes, carbohydrates and water, respectively). Thermal treatment caused the denaturation and aggregation of the proteins, while the addition of gums induced a decrease in the sensitivity to heat treatment of the proteins. Formation of protein aggregates and gum-protein complexes was characterized by electrophoresis, differential scanning calorimetry, and particle size distribution. Heat treatment and addition of gums generated macrocomplexes with enhanced absolute value of ζ-potential, which contributed to the high colloidal stability of amaranth-based beverage. This beverage is suitable for vegans, celiac patients, and lactose intolerants.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Criotecnología de Alimento

Lean Strategies for Window Retrofit of Italian Office Buildings: Impact on Energy Use, Thermal and Visual Comfort

The aim of this paper is to explore lean retrofit strategies for transparent envelope of existing Italian office buildings, to improve their performance and to ensure low energy use and a good thermal and visual comfort. Solar and light control is necessary to prevent overheating in office buildings those generally present high internal loads. The effectiveness of solar window films use in Italian buildings context is here investigated, in comparison with other strategies like the use of internal roller blinds and the substitution of the existing window panes with high performance ones. A sensitivity analysis was assessed to evaluate the office unit primary energy use under different retrofit solution, weather conditions and window to wall ratio. A conventional existing office unit was modeled in EnergyPlus and LBNL Radiance to assess heating, cooling and lighting energy demand coupled with visual comfort parameters. Thermal comfort was evaluated hourly in accordance with ISO 7730. The results are presented with a cost - benefit analysis to understand the best retrofit solution

Parametric Assessment to Evaluate and Compare the Carbon Footprint of Diverse Manufacturing Processes for Building Complex Surfaces

At present, building design is faced with a need to properly manage complex geometries and surfaces. This fact is not only driven by the increased demand for visually stunning spaces but also stems from the rise of new design paradigms, such as “user-centred design”, that include bespoke optimization approaches. Nevertheless, the escalating adoption of customized components and one-off solutions raises valid concerns regarding the optimal use of energy and resources in this production paradigm. This study focuses on the Life Cycle Assessment of a novel Cement–Textile Composite (CTC) patented material. It combines a synthetic reinforcing textile with a customized concrete matrix, to generate rigid elements that are able to statically preserve complex spatial arrangements, particularly double-curvature surfaces. Moreover, the CTC offers a low-volume cost-effective alternative for custom-made cladding applications. The study performed a comparative carbon footprint assessment of the CTC production process in contrast to other technologies, such as CNC milling and 3D printing. To facilitate meaningful comparisons among diverse construction alternatives and to derive generalized data capable of characterizing their overall capacity, independent of specific production configurations, the present study implemented a generalized parametric shape of reference defined as a bounding box (BBOX), which encloses the volume of the target shape. Comparing different production technologies of the same shape with the same BBOX results in a significant carbon saving, up to 9/10th of the carbon footprint, when the CTC technology is adopted. The study therefore highlights the potential environmental advantages of CTC in the fields of architectural design and building engineering

Exigência de manutenção e eficiência de deposição de lisina em suínos

The objective of this work was to determine the maintenance requirement and the deposition efficiency of lysine in growing pigs. It was used the incomplete changeover experimental design, with replicates over time. Twelve castrated pigs with average body weight (BW) of 52±2 kg were kept in metabolism crates with a controlled temperature of 22°C. The diets were formulated to supply 30, 50, 60, and 70% of the expected requirements of standardized lysine, and provided at 2.6 times the energy requirements for maintenance. The trial lasted 24 days and was divided into two periods of 12 days: seven days for animal adaptation to the diet and five days for sample collection. The increasing content of lysine in the diet did not affect dry matter intake of the pigs. The amount of nitrogen excreted was 47% of the nitrogen intake, of which 35% was excreted through feces and 65% through urine. The estimated endogenous losses of lysine were 36.4 mg kg-1 BW0.75. The maintenance requirement of lysine for pigs weighing around 50 kg is 40.4 mg kg-1 BW0.75, and the deposition efficiency of lysine is 90%.O objetivo deste trabalho foi determinar a exigência de manutenção e a eficiência de deposição de lisina em suínos em crescimento. Utilizou-se o delineamento experimental permutável, com repetições ao longo do tempo. Doze suínos castrados com peso vivo (PV) médio de 52±2 kg foram alojados em gaiolas metabólicas, com temperatura controlada de 22°C. As dietas foram formuladas para fornecer 30, 50, 60 e 70% das exigências esperadas de lisina estandardizada e fornecidas para atender 2,6 vezes a exigência de energia para manutenção. O experimento teve duração de 24 dias e foi dividido em dois períodos de 12 dias: sete para adaptação dos animais à dieta e cinco para coleta de amostras. O teor crescente de lisina na dieta não influenciou a ingestão de matéria seca pelos suínos. A quantidade de nitrogênio excretado foi de 47% do ingerido, dos quais 35% foram excretados pelas fezes e 65% pela urina. As perdas endógenas de lisina estimadas foram de 36,4 mg kg-1 PV0,75. A exigência de manutenção de lisina em suínos com aproximadamente 50 kg é de 40,4 mg kg-1 PV0,75, e a eficiência de deposição de lisina é de 90%