Nathan Mendes

Nathan Mendes
Pontifícia Universidade Católica do Paraná (PUC-PR) · Polytechnic School

PhD

About

182
Publications
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2,578
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Publications

Publications (182)
Article
In the design context of Near-Zero Energy Buildings (nZEBs) and smart cities, robust and versatile optimization methods are needed to be coupled to simulation tools. In this way, the paper presents optimization algorithms coupled to a software with a capability to precisely simulate solar radiation availability by using a graphical pixel counting t...
Article
Full-text available
The phenomenon of summer mortality in Pacifi c oysters cultures also occurs in Brazilian crops, with predominance in the adult phase, generating signifi cant losses for local producers. In the search for a technological solution to mitigate its effects, the mechanical vapour compression and hydraulic refrigeration concepts are evaluated as two prop...
Article
A two-dimensional model is proposed for energy efficiency assessment through the simulation of heat transfer in building envelopes, considering the influence of the surrounding environment. The model is based on the Du Fort–Frankel approach that provides an explicit scheme with a relaxed stability condition. The model is first validated using an an...
Preprint
Full-text available
A two-dimensional model is proposed for energy efficiency assessment through the simulation of heat transfer in building envelopes, considering the influence of the surrounding environment. The model is based on the Du Fort–Frankel approach that provides an explicit scheme with a relaxed stability condition. The model is first validated using an an...
Data
Front Matter (Pages i-xviii) of the book: "Numerical Methods for Diffusion Phenomena in Building Physics: A Practical Introduction" by Nathan Mendes, Marx Chhay, Julien Berger and Denys Dutykh
Data
Back Matter (Pages 233-245) of the book: "Numerical Methods for Diffusion Phenomena in Building Physics: A Practical Introduction" by Nathan Mendes, Marx Chhay, Julien Berger and Denys Dutykh
Article
Multi-criteria design techniques applied to the analysis of shading devices of buildings have arisen as useful tools for architects. Even though several techniques have been applied to shading devices with simple geometries, they usually require numerous simulations to suitably complete the analysis, making the optimization process time-consuming....
Article
Full-text available
This article proposes an efficient explicit numerical model with a relaxed stability condition for the simulation of heat, air and moisture transfer in porous material. Three innovative approaches are combined to solve the system of two differential advection-diffusion equations coupled with a purely diffusive equation. First, the DuFort-Frankel sc...
Book
This book is the second edition of Numerical methods for diffusion phenomena in building physics: a practical introduction originally published by PUCPRESS (2016). It intends to stimulate research in simulation of diffusion problems in building physics, by providing an overview of mathematical models and numerical techniques such as the finite diff...
Article
Full-text available
Building Energy Simulation (BES) tools commonly use 1-D formulation for computing conductions loads through building envelopes. As this assumption may cause significant errors on the prediction of building energy and thermal performance, this work proposes a methodology for taking into account the 3-D heat transfer phenomenon nature and compare the...
Article
Moisture is one of the main issues in building disorders. It can lead to microorganism's growth, material deterioration and impact on energy consumption. A comprehensive overview on the scale of the country considering climatic conditions may be an important starting point for potential moisture risks in building analyses. In this paper, we present...
Chapter
In the field of building physics, diffusion phenomena started to be extensively modeled in the 70s (because of the oil crisis) to develop building-performance-simulation programs for the adoption of rational policies of energy conservation. However, existing tools might still present inconsistent scenarios of the actual occurrences in buildings, es...
Chapter
This chapter is organized as follows. First, we present some theoretical bases behind spectral discretizations in Sect. 8.1. An application to a problem stemming from the building physics is given in Sect. 8.3. Finally, we give some indications for the further reading in Sect. 8.4. This document contains also a certain number of Appendices directly...
Chapter
Above in Chap. 3 the basic finite differences approaches were presented. In particular, it was shown that explicit discretizations are subject to some additional constraints if one wants to have a stable numerical scheme. These restrictions are known in the literature under the name of Courant–Friedrichs–Lewy conditions [43]. For parabolic diffusio...
Chapter
In building physics, as mentioned in Chaps. 2 and 3, numerical models used to predict heat and moisture transfer involve different characteristic time and lengths. Simulation of building behavior is generally analyzed on a time scale of 1 year (or more). However, the phenomena and particularly the boundary conditions evolve in seconds. The geometri...
Chapter
This chapter is devoted to a practical presentation of the finite-element method (FEM). The focus is on the construction of numerical schemes rather than on the numerical properties that this approach benefits; References [5, 106] provide an introduction. A very large literature survey, sorted by fundamental references, mathematical foundations, ap...
Chapter
Since the main focus of the Ph.D. school is set on the diffusion processes (molecular diffusion, heat and moisture conduction through the walls, etc.), it is desirable to explain how this research started and why the diffusion is generally modeled by parabolic PDEs [61]. The historic part of this chapter is partially based on [159].
Chapter
In many engineering problems, including building modeling, the relevant information lies at the surface of a domain. In addition, only a few point-wise evaluations may be needed. Thus, classical numerical approaches would require a whole domain computation, which requires a considerable amount of information (and computation effort). The idea of us...
Chapter
The first two parts of this book provided some theoretical background for solving diffusion problems in building physics and presented traditional (finite differences and finite elements) and nontraditional numerical methods (boundary integral approach, reduced order methods, and spectral methods). In addition, some practical examples were provided...
Chapter
This chapter is entirely devoted to numerical methods, keeping in mind that the main application is on diffusion processes in building physics. However, the presentation is oriented to the practical construction of numerical schemes with an overview of their elementary numerical properties.
Conference Paper
Full-text available
Thermal comfort conditions may vary substantially within an air-conditioned room equipped by split-type systems. In this work, the comfort conditions in a classroom were evaluated experimentally based on the PMV index, according to ISO 7730 Standard that defines the thermal satisfaction in occupied environments. The experiment was carried out at th...
Conference Paper
Full-text available
In this paper, the results of the validation modeling of glazing systems and an application based on Semi-transparent organic photovoltaics (ST-OPVs) are re-ported. A numerical code was developed for research purposes to improve the glazing modeling in building energy performance taking into account spectral radiative properties in glazing, buildin...
Conference Paper
Full-text available
A new Building and Environment Simulation Platform (BESP) has been conceived to be an advanced multidimensional simulation platform for fast and accurate assessment of energy and hygrothermal performance of building elements, buildings and building communities by means of an intelligent co-simulation approach among building energy simulation tools...
Article
A precise hygrothermal model is essential to predict the energy performance of building envelopes providing coupled transport of mass (moisture and air) and heat through porous elements, considering phase change and all heat transfer modes, including the radiative transfer through fibrous materials. Therefore, a new mathematical model, called CAR-H...
Article
Predictions of physical phenomena in buildings are carried out by using physical models formulated as a mathematical problem and solved by means of numerical methods, aiming at evaluating, for instance, the building thermal or hygrothermal performance by calculating distributions and fluxes of heat and moisture transfer. Therefore, the choice of th...
Preprint
Predictions of physical phenomena in buildings are carried out by using physical models formulated as a mathematical problem and solved by means of numerical methods, aiming at evaluating, for instance, the building thermal or hygrothermal performance by calculating distributions and fluxes of heat and moisture transfer. Therefore, the choice of th...
Article
Full-text available
Moisture is one of the leading causes responsible for the worst of health conditions and energy performance in households and workplaces. To avoid it, the coupling between a combined heat, air and moisture (HAM) model and a CFD code becomes a crucial research topic to provide accurate results for real problems found in the building sector. Therefor...
Article
Pixel counting (PxC) emerged as a powerful technique for external solar shading calculations of buildings, providing accurate results with great computational efficiency even for dense geometries. Motivated by this fact and because the technique can be also adapted to cope with interior surfaces without further ado, this paper aims at experimentall...
Article
Full-text available
Clay-based materials are the most traditional components of buildings. To improve their performance in a sustainable way, agents can be mixed to fired clay acting as a pore-forming factor. However, firing temperatures highly influence their microstructure which is closely linked to a material’s final performance as a ceramic block. To highlight the...
Article
It is well known that thermal insulation is a leading strategy for reducing energy consumption associated to heating or cooling processes in buildings. Nevertheless, building insulation can generate high expenditures so that the selection of an optimum insulation thickness requires a detailed energy simulation as well as an economic analysis. In th...
Preprint
This work presents a detailed mathematical model combined with an innovative efficient numerical model to predict heat, air and moisture transfer through porous building materials. The model considers the transient effects of air transport and its impact on the heat and moisture transfer. The achievement of the mathematical model is detailed in the...
Preprint
It is well known that thermal insulation is a leading strategy for reducing energy consumption associated to heating or cooling processes in buildings. Nevertheless, building insulation can generate high expenditures so that the selection of an optimum insulation thickness requires a detailed energy simulation as well as an economic analysis. In th...
Preprint
This work presents an efficient numerical method based on spectral expansions for simulation of heat and moisture diffusive transfers through multilayered porous materials. Traditionally, by using the finite-difference approach, the problem is discretized in time and space domains (Method of lines) to obtain a large system of coupled Ordinary Diffe...
Preprint
This work presents an alternative view on the numerical simulation of diffusion processes applied to the heat and moisture transfer through porous building materials. Traditionally, by using the finite-difference approach, the discretization follows the Method Of Lines (MOL), when the problem is first discretized in space to obtain a large system o...
Article
This article describes the development of a new instructional design (ISD) to promote building energy simulation (BES) education. The study is based upon education fundamentals combined with computer-based learning and hypermedia to enable the development of a BES-based distance learning system. Some cognitive tools are established such as: (i) an...
Conference Paper
Full-text available
The correct characterization of different materials assists in improving the results obtained via physical and numerical models. This study consists of the development of a numerical algorithm based on experimental data to obtain the spectral values of the index of refraction (n) and the coefficient of extinction (k) of several types of glasses ava...
Poster
Full-text available
Análise comparativa entre duas obras unifamiliares de alto padrão, que receberam os seguintes nomes: Residencia da Araucária Descampado (2013) e Residência Villacayo (2012)
Article
Full-text available
It is of great concern to produce numerically efficient methods for moisture diffusion through porous media, capable of accurately calculate moisture distribution with a reduced computational effort. In this way, model reduction methods are promising approaches to bring a solution to this issue since they do not degrade the physical model and provi...
Article
Full-text available
This pilot study aims to analyze the solar radiation transmission, daylight performance and glare reduction probability of complex shape solar control devices, developed with parametric modeling and digital fabrication. As methodology, initially the Rhinoceros3D+Grasshopper digital tools suite was used for the parametric modeling of solar control d...
Article
This work presents an alternative view on the numerical simulation of diffusion processes applied to the heat and moisture transfer through multilayered porous building materials. Traditionally, by using the finite-difference approach, the discretization follows the Method Of Lines (MOL), when the problem is first discretized in space to obtain a l...
Article
This work presents an efficient numerical method based on spectral expansions for simulation of heat and moisture diffusive transfers through multilayered porous materials. Traditionally, by using the finite-difference approach, the problem is discretized in time and space domains (Method of lines) to obtain a large system of coupled Ordinary Diffe...
Article
One possibility to improve the accuracy of building performance simulation (BPS) tools is via co-simulation techniques, where more accurate mathematical models representing particular and complex physical phenomena are employed through data exchanging between the BPS and a specialized software where those models are available. This article performs...
Article
Full-text available
Comparisons of experimental observation of heat and moisture transfer through porous building materials with numerical results have been presented in numerous studies reported in the literature. However, some discrepancies have been observed, highlighting underestimation of sorption process and overestimation of desorption process. Some studies int...
Article
A computational procedure known as co-simulation has been proposed in the literature as a possibility to extend the capabilities and improve the accuracy of building performance simulation (BPS) tools. Basically, the strategy relies on the data exchanging between the BPS and a specialized software, where specific physical phenomena are simulated mo...
Conference Paper
Full-text available
External long-wave radiative heat transfer is a typical boundary condition problem in building physics and the solution of the Radiative Transfer Equation (RTE) involve important mathematical skills to apply a simple model and still nowadays the computational cost in algorithms for solving the integral-differential RTE is not explicit implemented i...
Article
This paper presents an experimental validation procedure of two solar shading calculation techniques - pixel counting (PxC) and polygon clipping (PgC) - and an inter-software comparison to highlight the capabilities and efficiency of each solar shading calculation method. For the first purpose, digital images were taken from the surfaces of small-s...
Conference Paper
Full-text available
Bringing advanced physics to building performance simulation (BPS) tools, by means of computational fluid dynamics (CFD) coupling, may enable significant improvement of accuracy on the prediction of energy consumption, thermal comfort, pollutant transport and mold growth risk. One of the challenges on coupling is the communication between whole-bui...
Article
This work is devoted to proposing a hybrid numerical–analytical method to address the problem of heat and moisture transfer in porous soils. Several numerical and analytical models have been used to study heat and moisture transfer. The complexity of the coupled transfer in soils is such that analytical solutions exist only for limited problems, wh...
Book
This book intends to stimulate research in simulation of diffusion problems in building physics, by first providing an overview of mathematical models and numerical techniques such as the finite difference and finite-element methods traditionally used in building simulation tools. Then, nonconventional methods such as reduced order models, boundary...
Article
This paper proposes the use of a Spectral method to simulate diffusive moisture transfer through porous materials as a Reduced-Order Model (ROM). The Spectral approach is an a priori method assuming a separated representation of the solution. The method is compared with both classical Euler implicit and Crank-Nicolson schemes, considered as large o...
Article
Since the 1970s, due to the worldwide energy crisis, some countries have adopted severe legislation to promote energy efficiency in buildings. The electrical power utilized in buildings is directly related to the equipment required to provide thermal comfort to occupants. In this context, one of the most important factors that determine the choice...
Article
This paper aims at estimating the sorption isotherm coefficients of a wood fiber material using experimental data. First, the mathematical model, based on convective transport of moisture, the Optimal Experiment Design (OED) and the experimental set-up are presented. Then, measurements of relative humidity within the material are carried out, after...
Article
This paper presents a practical application of the concept of Optimal Experiment Design (OED) for the determination of properties of porous materials with in-situ measurements and an identification method. First, an experimental set-up was presented and used for the measurement of relative humidity within a wood fibre material submitted to single a...
Article
Implicit schemes require important sub-iterations when dealing with highly nonlinear problems such as the combined heat and moisture transfer through porous building elements. The computational cost rises significantly when the whole-building is simulated, especially when there is important coupling among the building elements themselves with neigh...
Article
Moisture affects significantly the energy performance of air conditioning systems, the durability of materials, and the health of occupants. One way of reducing those effects, without increasing the energy costs, is by means of using porous material ability of absorbing and releasing moisture from/to the adjacent environment, which attenuates the i...
Article
When comparing measurements to numerical simulations of moisture transfer through porous materials a rush of the experimental moisture front is commonly observed in several works shown in the literature, with transient models that consider only the diffusion process. Thus, to overcome the discrepancies between the experimental and the numerical mod...
Article
In this paper, an innovative method to minimise energy losses through building envelopes is presented, using the Proper Generalised Decomposition (PGD), written in terms of space x, time t, thermal diffusivity and envelope thickness L. The physical phenomenon is solved at once, contrarily to classical numerical methods that cannot create a paramete...
Article
Implicit schemes have been extensively used in building physics to compute the solution of moisture diffusion problems in porous materials for improving stability conditions. Nevertheless, these schemes require important sub-iterations when treating nonlinear problems. To overcome this disadvantage, this paper explores the use of improved explicit...
Conference Paper
Full-text available
An algorithm has been developed for the determination of incidence-angle dependent radiative properties and averaged properties of glazing systems based on simple performance indicators. First, the results are obtained using a computer code that applies statistical methods, multiple correlations for data treatment, and a mathematical approach to ob...
Conference Paper
Full-text available
The Brazilian state of Santa Catarina is responsible for more than 95% of the total bivalve mollusc production in Brazil, with the Pacific oyster being its second main product. The specie farmed along Santa Catarina´s coast is well adapted to the coastal environmental conditions, allowing oyster harvesting once a year. Nevertheless, the water tempe...
Conference Paper
Full-text available
Moisture is one of the main issues in building disorders. It can lead to microorganism's growth, discomfort, material deterioration and impact on energy consumption. In Brazil, there is a lack of assessment of the moisture risk potential in a comprehensive point of view, considering that most of the country is located in a tropical climate with imp...