Summer Overheating in a New Multi-storey Building in Berlin: Numerical Study for Improving the Indoor Microclimate

Abstract The topic of indoor overheating in a modern and well-insulated building is investigated. A real case study is proposed, where, even if the summer ambient conditions are not extreme, thermal discomfort has been verified during the first years of operations. The office building, built recently in Berlin, fulfils the German requirements in matter of energy performance of buildings and heat protection in summertime. Active system for the space cooling are not installed. In the frame of the new international approach to the cost-optimality, by adopting the adaptive comfort criteria for naturally-ventilated buildings, strategies for improving the indoor conditions during the cooling season are here investigated, by analysing various typologies and management strategies for solar shadings

Thermal Dynamic Insulation: Numerical Modeling in a Transient Regime and Application to Alternative Aviary Houses

Abstract The paper proposes a numerical model for investigating the energy performance of thermal dynamic insulation in transient conditions. This technology consists of porous building components that are permeable to airflow, ensuring high levels of energy performance and IAQ. The model is implemented in MATLAB environment and allows an accurate evaluation of heat transfer through porous media, with the final purpose of quantifying the energy benefits deriving from dynamic insulation. Beyond its presentation, the model is used to investigate the implementation of a dynamically-insulated ceiling to an alternative aviary house for laying-hens, located in Des Moines, Iowa (U.S.). The proposed system produces thermal, energy and economical savings in both cold and warm seasons

Thermal Performance of an Electric-Driven Smart Window: Experiments in a Full-Scale Test Room and Simulation Model

This paper reports the results of experimental tests and numerical simulations aimed at evaluating the performance of an electric-driven smart window with respect to solar control in buildings. The experimental performances of the electric-driven smart window were evaluated using a south oriented full scale experimental facility designed and realized. The tests were carried out during the summer under real sky conditions upon varying the state of the electricdriven smart window (clear and milky). In the first part of the paper, the experimental results are discussed in terms of surface temperature of glazings as well as indoor air temperature in order to highlight the potential benefits on thermal comfort associated to the application of electric-driven smart windows. In the second part of this paper, the experimental data are compared to the numerical results generated through a simulation model of the electric-driven smart window in order to assess its reliability under different operating scenarios. Finally, the simulation model is used to quantify the potential cooling load reduction deriving from the integration of electric-driven smart windows in an office façade located in Naples (Italy)

Energy Performance of Cool-colors and Roofing Coatings in Reducing the Free Solar Gains during the Heating Season: Results of an In-Field Investigation☆

Abstract Today, it is not well-known the impact of cool roofs during heating season in balanced climates. Proposed study tries to quantify the increase of energy demands of buildings characterized by high-reflective and high-emissive coatings of roof, by means of experiments and numerical simulations. Three coatings are investigated with different solar absorptance and thermal emittance. The experiments have been carried out at the living lab of the University of Sannio, a full-scale test-room, provided with a large flexibility in terms of variability of the thermal envelope and air-conditioning system. Moreover, numerical evaluations of heating and annual energy consumptions are presented

energy refurbishment of a university building in cold italian backcountry part 2 sensitivity studies and optimization

Abstract The first part of this study provided a discussion about the methodological approach for designing energy refurbishment measures of buildings. The case study is a building owned by University of Molise, in Campobasso, a cold Italian city. The reference scenario is a numerical model built after deep investigations, and thus surveys, questionnaires, documents and experimental measurements on the real building. Then, a calibrated energy model was presented. In this second part, starting from the calibrated model, some energy retrofit measures have been implemented. The obtained results allow to discuss two key points for researches in matter of energy refurbishment of buildings: a) the importance of using validated models to simulate the present performance; b) the environmental benefits and the economic implications of a deep energy refurbishment

energy refurbishment of a university building in cold italian backcountry part 1 audit and calibration of the numerical model

Abstract The study provides a methodological approach for designing energy refurbishment measures of buildings, enabling to understand the uncertainty of using numerical modelling and the real impacts due of adopting some energy efficiency technologies. The case study is a University building of the centre of Italy, and the reference scenario has been supported by various in-situ surveys, investigations and evaluations of the indoor comfort. Collected data, together with a comparison with energy bills, has allowed a proper calibration of a numerical model simulated by means EnergyPlus. All this phase is described in this paper, while a second part will discuss the energy retrofit and the building energy optimization

Pennes' bioheat equation vs. porous media approach in computer modeling of radiofrequency tumor ablation

[EN] The objective of this study was to compare three different heat transfer models for radiofrequency ablation of in vivo liver tissue using a cooled electrode and three different voltage levels. The comparison was between the simplest but less realistic Pennes' equation and two porous media-based models, i.e. the Local Thermal Non-Equilibrium (LTNE) equations and Local Thermal Equilibrium (LTE) equation, both modified to take into account two-phase water vaporization (tissue and blood). Different blood volume fractions in liver were considered and the blood velocity was modeled to simulate a vascular network. Governing equations with the appropriate boundary conditions were solved with Comsol Multiphysics finite-element code. The results in terms of coagulation transverse diameters and temperature distributions at the end of the application showed significant differences, especially between Pennes and the modified LTNE and LTE models. The new modified porous media-based models covered the ranges found in the few in vivo experimental studies in the literature and they were closer to the published results with similar in vivo protocol. The outcomes highlight the importance of considering the three models in the future in order to improve thermal ablation protocols and devices and adapt the model to different organs and patient profiles.This work was supported by the Spanish Ministerio de Economia, Industria y Competitividad under "Plan Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad", Grant No "RTI2018-094357-B-C21" and by the Italian Government MIUR Grant No "PRIN-2017F7KZWS".Tucci, C.; Trujillo Guillen, M.; Berjano, E.; Iasiello, M.; Andreozzi, A.; Vanoli, GP. (2021). Pennes' bioheat equation vs. porous media approach in computer modeling of radiofrequency tumor ablation. Scientific Reports. 11(1):1-13. https://doi.org/10.1038/s41598-021-84546-6S113111Chu, K. F. & Dupuy, D. E. 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nzeb target for existing buildings case study of historical educational building in mediterranean climate

Abstract A key element of the Energy Performance of Building Directive 2010/31/EU is the introduction of nearly zero energy building (NZEB) standard for new constructions. However, considering the very low rate of new built volume, the major change for achieve the sustainable grow of the European economy, appears to be the renovation of existing building stock. But, is it possible to reach very low or nearly zero energy standard during refurbishment design? Proposed paper tries to answer this question, evaluating if the refurbishment of historic architectures to very low energy need is possible and economically feasible. With reference to a case study, this paper investigates the cost-optimal energy refurbishment of a Renaissance-style palace, located in the center of Naples, South Italy. The adopted methodology consists of various steps. Firstly, a model of the building has been accurately built and calibrated. Then, it has been used to evaluate possible interventions concerning both the envelope and the energy systems. The best solutions, chosen according to the European methodology of cost-optimality, have been combined in a last simulation. The results show that great energy savings as well as economic and environmental improvements are possible, although heritage buildings present a less flexibility in the proposal of energy efficiency measures

Development of an Electric-Driven Smart Window Model for Visual Comfort Assessment

Smart windows, especially those electric-driven, represent one of the most advanced technologies for controlling solar radiation. For a correct use, it is necessary to understand their real behaviour through in-situ measurements on full-scale application as well as calibrating and validating visual simulation models capable of predicting their performances. In this paper, the preliminary results of current research activities aimed at developing simulation models of electric-driven full-scale glazing are presented. The research activities started with the assessment of the visible solar transmittance as a function of light incident angle through in-situ measurements; different models, with related values, of the visible solar transmittance were considered. For each simulation model, the corresponding transmittance value was set in the RADIANCE “trans” material model and the simulated illuminance values, for a defined acquisition point of a test-facility, were then compared with the experimental data. Finally, for each model, indoor luminance distributions were reported considering a typical office seating position. Preliminary results, based on the in-situ measurements approach, highlighted a sufficient accuracy for one of the models adopted; further analyses are needed in order to upgrade the simulation models available and assess the effective performances of these windows

Multi-Objective Optimization for Cooling and Interior Natural Lighting in Buildings for Sustainable Renovation

In order to achieve the ‘nearly zero-energy’ target and a comfortable indoor environment, an important aspect is related to the correct design of the transparent elements of the building envelope. For improving indoor daylight penetration, architectural solutions such as light shelves are nowadays commercially available. These are defined as horizontal or inclined surfaces, fixed or mobile, placed on the inner and/or the outer side of windows, with surface features such to reflect the sunlight to the interior. Given the fact that these elements can influence different domains (i.e., energy need, daylighting, thermal comfort, etc.), the aim of this paper is to apply a multi-objective optimization method within the design of this kind of technology. The case study is a student house in the University of Athens Campus, subject to a deep energy renovation towards nZEB, under the frame of H2020 European project Pro-GET-onE (G.A No 723747). Starting from the numerical model of the building, developed in EnergyPlus, the multi-objective optimization based on a genetic algorithm is implemented. The variables used are various light shelves configurations by differing materials and geometry, as well as different window types and interior context scenarios. Finally, illuminance studies of the pre- and post-retrofit building are also provided through Revit illuminance rendering