Papers by Ulrich Filippi Oberegger
Learning and analytics in intelligent systems, 2024
Zenodo (CERN European Organization for Nuclear Research), Dec 21, 2023
Building Simulation Conference proceedings, Aug 28, 2013
Sustainable Cities and Society, Nov 1, 2021
Abstract Life cycle cost analysis represents a strategic tool for supporting the decision-making ... more Abstract Life cycle cost analysis represents a strategic tool for supporting the decision-making process while designing a new building or a renovation towards a nearly zero-energy target. Nevertheless, one of the main obstacles undermining the wide application of life cycle cost analysis deals with the effort in collecting the whole set of inputs and boundary conditions and the associated reliability of the results. To address the issue, this work compares the application of different sensitivity analysis methodologies on eleven nearly zero-energy buildings with different uses and in several European contexts, highlighting the strengths and weaknesses. Moreover, it introduces and assesses an approach for applying sensitivity analysis in life cycle cost evaluations to find an effective balance between the effort for calculation, data collection and the reliability of life cycle cost. A main result is the demonstration of a sensitivity analysis procedure to identify and evaluate parameters and boundary conditions with the largest impact on the life cycle cost of the analysed buildings, namely, the interest rate, construction and equipment maintenance costs, structural element costs, and electricity prices. These parameters lead to variations in LCC of up to 37%, with an average of 26% around the median. By focusing a more detailed analysis on these parameters, we could assess the potential life cycle cost range due to input uncertainties with a high degree of confidence while keeping efforts for practitioners reasonable.
Energy and Buildings, Mar 1, 2020
Policy makers need scientific support to set ambitious yet realistic environmental targets for th... more Policy makers need scientific support to set ambitious yet realistic environmental targets for the transition to energy efficient buildings and to develop cost-effective policies to meet these targets, but comprehensive, manageable procedures to this aim are still lacking. Our proposed method ranges from baseline creation to transition scenarios depending on annual retrofit budget and specifies the buildings to renovate according to location, size, and age, and the energy efficiency measures to apply based on cost and energy saving. We show how to extrapolate a baseline from few available data, determine retrofit costs, and create calibrated models to estimate energy savings. Retrofits are ranked by levelized cost of saved energy, which ensures that for any budget allocated to retrofit maximum energy savings are obtained at minimum cost to society. The results are summarized in an energy efficiency cost curve enabling policy makers to estimate potential costs and energy savings. We demonstrate the method on a housing stock in northern Italy and show that facade insulation of old buildings in colder climates can compete with gas heating. About 60% baseline energy consumption can be saved doubling current investments, while a maximum saving of 75% requires over three times the current investments.
Procedia Engineering, Jun 1, 2010
Energy and Buildings, Dec 1, 2015
Uncalibrated building energy models, as well as models calibrated only on a single performance in... more Uncalibrated building energy models, as well as models calibrated only on a single performance indicator such as energy consumption or indoor temperature, can be significantly unreliable regarding model parameters and other performance indicators. The risk of obtaining a calibrated model whose parameters are far from the actual values is particularly high in historic buildings because of the increased uncertainty about the building construction. In this paper, we propose a calibration methodology aimed at reducing this risk and apply it on a medieval building. The building was modeled in EnergyPlus based on an energy audit. A sensitivity analysis was performed to identify significant parameters affecting the errors between simulated and monitored indoor air temperatures. The model was calibrated on the hourly indoor air temperatures in summer by minimizing the root mean square error averaged over the building using a particle swarm optimization algorithm. A second calibration was performed by varying the parameters of a representative room. By comparing the results from these two calibrations, we obtained indications about the accuracy of the model parameters. Finally, the model was validated on hourly indoor air and surface temperatures in winter where temperature root mean square errors ranged from 0.4 to 0.8 K.
Building and Environment, 2021
Shopping centres are commonly laid out as small individual stores connected by transitional space... more Shopping centres are commonly laid out as small individual stores connected by transitional spaces. Setpoint temperatures used to control transitional spaces are normally the same as in traditional indoor environments despite substantial differences in use, time of permanence and users' needs. Currently, there are no comfort guidelines for transitional spaces and the literature lacks relevant studies on the topic. There is an untapped potential for energy savings and improved indoor environmental quality. The main objective of this work is to evaluate the suitability of Fanger's comfort model and adaptive comfort model for transitional spaces. We assessed users' thermal perception and potential impacting factors in three Italian shopping centres. 724 customers were interviewed on their thermal comfort, thermal sensation, thermal preference, and clothing level while experiencing the transitional space. In addition, the thermal environment at the interview locations (drybulb temperature, globe temperature, relative humidity, and air speed at different levels) and the outdoor temperature were monitored. The study demonstrated that Fanger's model and the adaptive comfort model are not suitable for transitional spaces. Customers were inclined to adapt to a much wider range of indoor environmental conditions. An operative temperature of up to 27.5 • C was still deemed comfortable by more than 80% of the customers. These results unlock a large potential for energy savings and pave the way for passive solutions such as natural ventilation.
Energy and Buildings, Sep 1, 2017
ARX models are an effective instrument to evaluate continuous building performance from insuffici... more ARX models are an effective instrument to evaluate continuous building performance from insufficient monitoring data. However, selecting the right model features is NP-hard. The problem of finding a minimal subset of informative inputs has been studied extensively in various fields but automatic, fast, and reliable procedures for finding optimal models for building performance evaluation are still missing. We propose a novel feature selection algorithm named Greedy Correlation Screening (GCS), which identifies a possible solution at a time by greedily maximizing the correlation between inputs and output and minimizing cross-correlations between inputs. These two objectives are competing, thus leading to best tradeoffs. Among these, the best model is automatically selected by applying filters and quality criteria such as the adjusted coefficient of correlation and non-correlation of residuals. The performance of the proposed heuristic method is compared to two of the best algorithms used in the field, such as GRASP for feature selection and NSGA-II (Non-dominated Sorting Genetic Algorithm). The application on a real case study demonstrates that the proposed method solves the problem of feature selection in building performance estimation efficiently and reliably. Moreover, the model creation is automatic, making it ideal for
Sustainability, May 30, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Journal of Astm International, 2010
We computed reaction forces and moments acting on a skier during a carved turn. We performed an i... more We computed reaction forces and moments acting on a skier during a carved turn. We performed an inverse and a forward dynamic analysis. For a run of an elite skier, marker positions on skier and skis were obtained as functions of time from a video analysis and smoothed by splines. Linear velocities and accelerations were computed by differentiating the splines, angular velocities, and accelerations via rotation matrices. The forces acting at the right ski were measured with two Kistler force plates. For the inverse dynamics, we used an adapted Hanavan model for a skier consisting of upper body, left and right thighs, shanks, and skis. Applied forces considered were weight and ski-snow friction. Drag was neglected. By prescribing a lateral weight distribution from the outer to the inner ski during the turn, reaction forces and moments at the left and right ankle, knee and hip joints were computed from the Newton–Euler equations of motion for constrained rigid multibody systems. The forward dynamics was performed with a three-segment model of a mono-skier consisting of trunk, thigh, and shank. Rotational joints were assumed in knee and hip. The track and the joint angles were prescribed. The inward lean angle was determined by a balance condition that led to nonholonomic constraints. After formulating the equations of motion in descriptor form, the resulting differential-algebraic system was solved with the numerical code RADAU5. Computed and measured reaction forces and moments agreed well within the accuracy of the measurements. The calculated joint loads are consistent with results from the literature. The forward dynamics model can be used to simulate consecutive ski turns. With parameter studies, the effects of slope, tracks, segment properties, ski-snow friction, and velocity of the skier on joint loads and performance of a run can be investigated. Further, injury mechanisms can be analyzed.
Building Simulation
A critical gap between the occupant behaviour research field and the building engineering practic... more A critical gap between the occupant behaviour research field and the building engineering practice limits the integration of occupant-centric strategies into simulation-aided building design and operation. Closing this gap would contribute to the implementation of strategies that improve the occupants’ well-being while reducing the buildings’ environmental footprint. In this view, it is urgent to develop guidelines, standardised methods, and supporting tools that facilitate the integration of advanced occupant behaviour models into the simulation studies. One important step that needs to be fully integrated into the simulation workflow is the identification of influential and non-influential occupant behaviour aspects for a given simulation problem. Accordingly, this article advances and demonstrates the application of the Impact Indices method, a fast and efficient method for screening the potential impact of occupant behaviour on the heating and cooling demand. Specifically, the m...
Sustainability
Reducing greenhouse gas (GHG) emissions and energy consumption in the building sector requires no... more Reducing greenhouse gas (GHG) emissions and energy consumption in the building sector requires not only improving the energy efficiency of buildings but also minimising material requirements, embodied emissions, and waste generation. Circular Economy (CE) principles can be applied to minimize resource extraction and waste generation in the building industry. However, to implement effective CE strategies, quantification and evaluation of materials accumulated in buildings are required. This study aims to provide accurate data and a detailed analysis of the materials available in the EU27 residential building sector. By elaborating the data provided by the H2020 European projects Hotmaps and AmBIENCe, the different materials used for floors, roofs, walls, windows, and insulation layers in single-family houses, multifamily houses, and apartment blocks in the different construction periods were quantified for each EU27 country. Considering results at the EU27 level, concrete and brick c...
Building Simulation Conference Proceedings
This database reports the detailed results of the work "Sensitivity analysis as support for ... more This database reports the detailed results of the work "Sensitivity analysis as support for reliable life cycle cost evaluation an application on eleven nearly zero-energy buildings in Europe" published on the journal Sustainable Cities and Society. In particular, it includes the main sensitivity indices and life cycle cost values of eleven nZEB buildings across Europe as calculated within the H2020 project CRAVEzero (Cost Reduction and market Acceleration for Viable nearly zero-Energy buildings).
The goal of this work is to demonstrate the coupling of energy and daylighting simulation for Com... more The goal of this work is to demonstrate the coupling of energy and daylighting simulation for Complex Fenestration Systems (CFS) using TRNSYS, one of the most user-friendly and complete software as regards the dynamic simulation of building systems. We wrote a custom TRNSYS building block, called Type, in C++ that performs the three-phase method using Radiance. The novel Type denominated Type_DLT exchanges data at every time step with the TRNSYS multi-zone building model known as Type 56. The connection between the two Types occurs through a set of equations that control the CFS based on the amount of exterior and interior daylight, solar gains and internal gains. The Bidirectional Scattering Distribution Function (BSDF) data has to be provided for each state of the CFS. The tool can be used to investigate how different controls of the CFS and occupant behaviors affect thermal and visual comfort and energy savings. We demonstrated the tool on a single zone model taken from a refurbi...
International Journal of Sustainable Energy Planning and Management, 2016
The present paper focuses on the energy system of the municipality of Bressanone-Brixen, located ... more The present paper focuses on the energy system of the municipality of Bressanone-Brixen, located in the North of Italy. The aim of this paper is to investigate various possible energy scenarios for this case study in order to improve the overall efficiency of the system. The different scenarios include high penetration of photovoltaics at urban level, considering the maximum rooftop PV potential of the local area. Different solutions have been analyzed in order to study the handling of the consequent excess of electricity production. Electric storage and a solution combining heat pumps and thermal storage have been evaluated to maximize the local use of the generated electricity. A deterministic approach (without the use of an optimization algorithm) and a heuristic optimization approach have been applied to evaluate the different possible configurations. The present analysis can be of interest for other cities in a mountain environment where the production from renewables is limite...
SUMMARY The energy diagnosis and the energy refurbishment of a historic building are in most of t... more SUMMARY The energy diagnosis and the energy refurbishment of a historic building are in most of the cases difficult. Not only there are seldom drawings with any constructive indica- tions, but often there are also limited possibilities to investigate the properties of the build- ing envelope because invasive measurements are not allowed. Dynamic simulation mod- els may be used not only to investigate the possible retrofit interventions and to optimize them, but also to improve the energy diagnosis by simulation model calibration and vali- dation from the measured performance. In this work, we analyzed the "Waaghaus" (weigh house), a historic building located in Bolzano/Bozen (Northern Italy), one of the eight case-studies within the FP7 project 3encult. It is a four storeys XIII century building with thick stone walls and a wooden roof located in the center of the city. The former use during the middle age was to weigh the products before they could go to the market. Today...
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Papers by Ulrich Filippi Oberegger