An Efficient Global Optimization Scheme for Building Energy Simulation Based on Linear Radial Basis Function

Motivation: The building performance optimization is considerably increasing since the design goals are moving from the solely energy saving target to the optimization of the overall performances, cost and sustainability objectives. The evolutionary algorithms coupled with building simulation codes are often used in academic researches, however, they are limited applied in actual building design. Indeed, the high number of expensive simulation runs required by evolutionary algorithms strongly limits their suitability for the professional practice. For this reason, an efficient optimization scheme is essential for the diffusion of the building performance optimization tools outside the academic world. What was done: The research focuses on the development of an efficient global optimization scheme (EGO) based on a radial basis function network (RBFN) meta-model to emulate the expensive function evaluation by means of the building energy simulation. In this surrogate model, each cost function can be approximated by a linear combination of unknown coefficient multiplied by a set of linear radial-basis function. In the proposed method, the surrogate model is firstly used in the evolutionary algorithm code to find the optimal solutions. Then, the actual fitness functions are evaluated for the optimal points by means of building simulation and the surrogate model is then update. These steps are continued until the convergence criterion is met. This efficient optimization scheme has been implemented in Matlab and verified on some test cases. The test bed of the method is the optimal building refurbishment of three simplified existing buildings, for which the optimal solutions have been also calculated by using the brute force approach. Finally, the EGO performances were also compared with those offered by the popular Non Sorting Genetic Algorithm (NSGA-II). Expected benefits of what was done: The results of this research show how the EGO algorithm is able to find a large number of optimal solutions with a reduced number of expensive simulation runs. This makes it possible to apply the algorithm to the optimization of building projects that use expensive simulation codes such as lighting models, CFD codes or coupled dynamic simulation of building and HVAC systems

Introduction to Pragmatism and Theories of Emergence

Emergence is a pivotal concept for interpreting the reality of natural and social human life in all its processual complexity. The recently renewed debate about this concept and the different forms of emergentism is particularly varied, widely referring to biology, metaphysics, philosophy of mind (Kim 1999, 2005, 2006a,b; Cunningham 2001; Pihlström 2002; El-Hani 2002; El-Hani & Pihlström 2002; Chalmers 2006; Bedau & Humphreys 2008; Corradini & O’Connor 2010; Okasha 2012; Humphreys 2016; Sarte..

Modelling Of The Thermal Behavior Of Walls And Floors In Contact With The Ground

One of the most complex configuration to model in detail, both in the dynamic simulation of buildings and in the analytical quasi steady-state calculations, is the thermal dispersion through the walls and the floor in contact with the ground. The problem consists in determining the boundary conditions of the external wall surface directly exposed to the soil, whose temperature cannot be considered undisturbed. Different studies, both experimental and numerical, have been carried out in the last decades in order to determine the ground boundary conditions, some of which have been used to elaborate the technical standard EN ISO 13370. This standard gives some indications about the conditions to be considered in the use of quasi steady-state methods and within the dynamic simulation. The evaluation of the simulation software in the specific context of the ground heat transmission, has also driven the IEA to define a specific series of validation cases, the BESTEST In-depth ground coupled heat transfer tests. The present research aim is to test implement reliable calculation procedures for the thermal dispersion through the building envelope towards the ground, in dynamic simulation modelling systems. In this work, a test case of the EN ISO 13370 standard has been modelled with FEM codes, both in steady-state conditions and also in periodic external conditions. Different types of floor have been considered, with different thickness and position of the insulation layer. The results have been compared with those calculated following the prescriptions of the standard EN ISO 13370

Effect of Solar Radiation Model on the Predicted Energy Performance of Buildings

The building energy balance is strictly connected with the solar irradiation. Therefore, a reliable estimation of the global irradiation incident on various tilted surfaces is essential in order to account for the solar heat gains. In many meteorological stations, only global solar radiation on a horizontal plane is monitored while, in some stations, also the direct and diffuse components are collected. However, only few stations measure the solar radiation incident on tilted surface. For these reasons, a variety of mathematical and empirical models have been proposed in the literature for both the subdivision of horizontal solar radiation into direct and diffuse components (horizontal diffuse irradiance models) and for the calculation of irradiation on tilted surfaces (irradiance models for tilted surfaces). Nevertheless, there is no pair of models that can provide results with the same reliability for different worldwide localities. This topic has been widely discussed in the literature by means of solar model validation against experimental data for a particular location. Little is still known about the propagation of these model uncertainties through the building energy balance. This research work investigates the extent to which the choice of solar radiation models affects the predicted energy performance of a set of simplified reference buildings. By means of a full factorial plan, a set of 72 simplified residential buildings is defined by changing the insulation and thermal inertia of opaque components, the windows surface and orientations and the solar heat gain coefficient of glazing. Moreover, a full combination of 22 horizontal diffuse irradiance models coupled with 12 irradiance models for tilted surfaces is implemented and used as a pre-processor of solar data used in building energy simulation codes (i.e. TRNSYS). Starting from these data, the hourly dynamic energy simulations were performed for several European locations. In particular, the Europe region has been divided in 5 zones considering the classes of annual solar radiation and, for each zone, a representative city was identified and used for this work. Finally, the distribution of monthly energy needs and peak loads are studied and discussed by means of statistical techniques, in order to generalize the found discrepancies and to correlate the deviations to the building envelope characteristics

Solar Irradiance Modelling And Uncertainty On Building Hourly Profiles Of Heating And Cooling Energy Needs

Building energy simulations require a detailed characterization of the boundary conditions in order to solve the air heat balance problem. While for dry and dew bulb temperatures and wind speed, hourly profiles can be successfully developed from raw data measurements, to be included in weather files, beam and diffuse solar irradiance on the external surfaces of the building envelope are not directly known. Measured global solar irradiance is rarely available for the possible orientations of buildings surfaces and when the distinction between the beam and diffuse irradiance components is recorded, it is only for horizontal measurements. Consequently, solar irradiance models are necessary to elaborate hourly beam and diffuse irradiation profiles on the various elements of the building envelope. We can distinguish the different models into two groups: horizontal diffuse irradiance models – to calculate the diffuse component on the horizontal plane starting from the global measurement, and irradiance models for tilted surfaces – to estimate the irradiance collected on tilted surface with a given orientation. Even if some models try to exploit some mathematical expressions to describe the phenomenon, most of them rely mainly on statistical correlations derived from empirical data. Since the samples of solar irradiance measurements used for the models development have been collected mostly in North America and European localities, these models are far from providing an adequate worldwide representativeness and none can be precisely defined as the best one. As observed in previous works in the literature and other authors’ works, the adoption of a pair of models for horizontal diffuse irradiance and for the irradiance on tilted surfaces introduces an uncertainty on the estimation of this specific boundary conditions in building energy simulation. However, different localities, building configurations and kind of energy need – heating and cooling, have different sensitivities to this suboptimal characterization of the solar irradiance. Thus, for some cases, the choice on the couple of models can affect significantly the simulation outputs and influences the robustness of the design solutions. Moreover, also the time discretization of the outputs can be relevant on the quantification of the uncertainty brought by the choice of solar irradiance models. Further expanding previous analyses, in this contribution, 22 horizontal diffuse irradiance models have been coupled with 12 irradiance models for tilted surfaces in order to develop hourly profiles of solar irradiance for 5 European localities (Berlin, Vienna, Trento, Rome and Messina). The 264 alternatives have been used as input in TRNSYS for the simulation of the hourly energy performances of a set of 72 simplified residential buildings, built varying parametrically insulation and thermal inertia of opaque components, windows surface and orientation and solar heat gain coefficient of glazing. The distributions of hourly heating and cooling energy needs along the year and for the different configurations of the sample have been studied in order to identify the building features enhancing the uncertainty due to the solar irradiance modelling on short-term outputs

An Epoxy Adhesive Crosslinked through Radical‐Induced Cationic Frontal Polymerization

AbstractUV‐initiated cationic frontal polymerization is exploited as a solvent‐free, extremely fast, and low‐temperature technique to obtain epoxy‐based adhesives. Epoxy formulations are prepared by blending commercial resins at different weight ratios and adding photo and thermal initiators at different percentages. In addition, the influence of other critical parameters, including the joint thickness, the nature of the adherends, and the temperature, is studied. As the reaction front is thermally sustained, the boundary conditions play a key role during the curing process and heat dissipation through the adherends in particular. The thermal properties of the epoxy formulation are studied through differential scanning calorimetry analysis, and the joint strengths are investigated by carrying out single lap off‐set shear tests under compression. The results demonstrate the feasibility of obtaining joints by means of the radical induced cationic frontal polymerization of the epoxy adhesives, which exhibit comparable epoxy group conversion and mechanical performances to the ones cured by traditional energy‐intensive techniques

Endomyocardial biopsy in the clinical context: current indications and challenging scenarios

Endomyocardial biopsy (EMB) is an invasive procedure originally developed for the monitoring of heart transplant rejection. Over the year, this procedure has gained a fundamental complementary role in the diagnostic work-up of several cardiac disorders, including cardiomyopathies, myocarditis, drug-related cardiotoxicity, amyloidosis, other infiltrative and storage disorders, and cardiac tumours. Major advances in EMB equipment and techniques for histological analysis have significantly improved diagnostic accuracy of EMB. In recent years, advanced imaging modalities such as echocardiography with three-dimensional and myocardial strain analysis, cardiac magnetic resonance and bone scintigraphy have transformed the non-invasive approach to diagnosis and prognostic stratification of several cardiac diseases. Therefore, it emerges the need to re-define the current role of EMB for diagnostic work-up and management of cardiovascular diseases. The aim of this review is to summarize current knowledge on EMB in light of the most recent evidences and to discuss current indications, including challenging scenarios encountered in clinical practice

Effects of different moisture sorption curves on hygrothermal simulations of timber buildings

Building energy simulations are a key tool to design high performance buildings capable of facing the future challenges and to help reaching the emissions reduction targets. Currently, thermal properties of materials used in most building energy simulations are assumed to be constant and not dependent of moisture content and temperature. Heat and moisture dynamic transfer models allow to simulate building envelope performance considering thermal resistance reduction due to moisture effects. These models are generally considered more accurate than the heat transfer models and they could be used to simulate the heat transfer (increased by water vapour storage) and the moisture buffering effect on the indoor environment. For the simulation to be performed, hygrothermal material properties should be known as functions of moisture content. Nevertheless, hygrothermal material properties are rarely available and correlations from the literature have to be used. In this study, the moisture storage curves of CLT, OSB and two types of wood fibre insulation have been measured with a dynamic vapour sorption analyser. The other hygrothermal properties are estimated from values measured in previous studies or taken from the literature. The simulations of two small single room buildings in four Italian locations are performed with the software EnergyPlus, considering an ideal HVAC system, to calculate the heating and cooling needs of the building. The HAMT (heat and moisture transfer) module of EnergyPlus is used. With the results presented in this study, it is possible to evaluate how an approximated curve affects the results of a whole-building simulation in terms of wall average water content, indoor air relative humidity and heating/cooling loads