1,721,023 research outputs found
Robustness of multi-objective optimization of building refurbishment to solar radiation model
No full textThe energy saving potential of existing buildings in highly urbanized world areas stimulates interest in the introduction of renovation measures. Due to the high economic impact of those interventions, special attention has to be paid to balance energy and economic
performance, leading to the definition of the best combination through multi-objective approach. The recourse to building simulation, to improve the resolution and discrimination capability between different renovation configurations, forces us to consider the quality of the input data and leads to robustness issues for the optimal solution. In this regard, a reliable estimation of the global irradiation incident on various tilted surfaces is essential in order to account for the solar heat gains. Nonetheless, many meteorological stations
monitor only global solar radiation on a horizontal plane. As a consequence, a variety of mathematical and empirical models have been proposed in the literature for both the subdivision of horizontal solar irradiation into direct and diffuse components and for the calculation of irradiation on tilted surfaces. Besides introducing intermodal uncertainty, no pair of diffuse and tilt irradiation models can provide results with the same reliability for worldwide localities different from those considered for the definition of each model.
This research work investigates the extent to which the choice of solar irradiation models affects the confidence levels of the optimal solutions provided by multiobjective optimizations. With this purpose, several multiobjective optimizations are carried out with different solar irradiation models. Semi-detached houses, penthouses and intermediate flat in multi-storey buildings are analyzed with the purpose of broadening the representativeness of the conclusions
Occupants' interaction with building services: Development of a camera-based method for detailed monitoring of windows, shadings, and lights
Full text linkSeveral energy gains or losses in buildings are influenced by occupant interactions with building services, such as lighting or HVAC systems, thermostat settings, and window and shading operations. Occupant behavior is usually triggered by discomfort, nevertheless actions taken to restore comfort can have an impact on final energy demand. Thus, an accurate energy assessment for both new and retrofit building design must properly account for occupant behavior, based on reliable models developed from real case studies and detailed monitoring. This work presents a new approach for continuous and non-intrusive monitoring of window opening angle, shading position, and lighting operation to determine the net air exchange area for ventilation. A camera-based device and a post-processing algorithm are developed, and a monitoring campaign over 6 month is carried out to showcase the monitoring system. The device consists of a camera setup connected to a microprocessor, and a dedicated script which enables the device to track window opening, shading movement and lighting operation through target and object identification. Results of the prototyping case study show that the proposed system can effectively detect window opening angles and shutter positions, dealing with multiple windows and shutters simultaneously and allowing the deployment of the benefits of continuous monitoring. The explored application is the direct use of the collected data for the calculation of natural ventilation rates from the net exchange area (EN 16798-7) over long term datasets. As future development, the monitoring system will be used to develop accurate behavioral models based on the experimental data to analyze and suggest the occupant’s response to discomfortable conditions in order to improve indoor air quality and save energy
Impact of solar irradiation models on building refurbishment measures from multi-objective optimization
Full text linkThe European energy regulations encourage the refurbishment of existing buildings in order to ensure a reduction of the energy use. The choice of the optimal solutions is actually a trade-off problem between conflicting goals. For this reason, multiobjective optimization techniques can be coupled with building energy simulation (BES). However, even if validated BES codes are used, some discrepancies arise due to the accuracy of implemented models, such as those related to the elaboration of solar irradiation profiles. This research work investigates the extent to which the choice of solar irradiation models can affect the robustness of the Pareto front for several building configurations in two Italian climates. The results highlight the building characteristics reducing the robustness of Pareto front solutions. Nonetheless, the analysis shows a low sensitivity of cost and energy optimal solutions to the uncertainty introduced by solar models
Building Simulation Applications BSA 2017 - Proceedings of 3rd IBPSA-Italy conference
Full text linkBuilding Simulation applications (BSA) 2017 was the third IBPSA-Italy conference on building performance Simulation to take place at the Free University of Bozen-Bolzano, from
8th to 10th February 2017. The main topics dealt with were the impact of micro-climate conditions on building performance, detailed modelling of physical phenomena and building
system components, optimization techniques for high performance buildings, energy retrofit and advanced HVAC controls, integrated performance analysis, and visual and
thermal comfort assessment.It featured more than 100 participants and more than 75 presentations, about 40 % of which from abroad – Austria, US, South Korea, Ireland, Switzerland
and the UK, among the first contributors. In addition, besides researchers, it also hosted a half-day special roundtable discussion about the potential and limitations of a set of simulation tools, attended by about 80 practitioners, to discuss the opportunities opened up to professionals by the use of building simulation, as well as the main barriers preventing its broader diffusion
Influence of the representativeness of reference weather data in multi-objective optimization of building refurbishment
Full text linkEnergy saving measures properly applied to the existing building stock can bring noticeable savings. In particular, optimal cost-effective solutions can be found through multi-objective optimization techniques, such as those based on genetic algorithms (GA), coupled with building energy simulation (BES). Although the robustness of GA multi-objective optimizations to the quality of the inputs is discussed in the literature, the role of the weather data file is not investigated in detail. For this reason, this work analysed the extent to which the method adopted for the development of reference weather data for BES can affect the optimal solutions. Considering a group of simplified building configurations and the location of Trento, Italy, many multi-objective optimizations are performed. The results show changes to both Pareto fronts and optimal retrofit solutions
The impact of thermal comfort in multi-objective optimization of buildings refurbishment
No full textThe European Committee is encouraging the Member States to adopt the so-called “cost optimal approach” to define new energy performance requirements for new and existing uildings. However, the cost-optimal should not neglect the indoor thermal comfort. The improvement of the building energy performance, especially if related to the addition of high insulation thickness, can increase the risk of overheating. A small energy input raises the internal temperature considerably. Therefore, in order to move beyond the mere economic optimization of retrofit interventions, it is important to understand what the solutions able to enhance the performance of the buildings are, also in terms of thermal comfort. In this paper, this problem has been investigated. The analysis has been carried out on a set of different residential building modules, representative of different building typologies and construction periods, located in two different climatic contexts. By means of a multi-objective optimization approach, the best combination of EEMs has been defined first optimizing only the energy and economic aspects, then the indoor thermal comfort has been added and the optimization re-run. A Genetic Algorithm (NSGA-II) coupled with a simulation tool has been used to optimize the different objectives
Building Simulation Applications BSA 2019 - Proceedings of 4th IBPSA-Italy conference
Full text linkUnlike the previous editions,the fourth Building Simulation Applications BSA 2019 Conference took place in June, from 19th to 21st, instead of during the winter period. For the biennial conference hosted by the Free University of Bozen-Bolzano, IBPSA Italy had to double its efforts, considering its concurrent commitment to the organization of Building Simulation 2019 in Rome. Even so, BSA 2019 featured more than 60 participants and around 130 different authors, with a significant presence of delegates from abroad and, in particular, from Austria. A different review process was introduced, with the full paper submission and review following the conference. Based on this, only 40 out of the 54 works presented during the conference in two parallel sessions were accepted for inclusion in this proceedings book
Multi-objective optimization for existing buildings retrofitting under government subsidization
No full textThe refurbishment of existing buildings allows remarkable improvements in energy performance, even by mature and off-the-shelf technologies. However, the pursuit of nearly zero energy buildings in renovation can lead to non-optimal solutions in terms of comfort. Besides, the initial cost can limit the owner in refurbishing buildings or drive the choice toward energy-efficiency measures with minimum initial cost at the expense of energy and non-energy performances. In this regard, financial incentives can be a key driver to stimulate renovation, mobilizing private investments and overcoming the high upfront costs and relatively long pay-back time of the retrofit. In the literature, the real effectiveness of incentives to improve both the comfort and the energy performance of the cost-optimal solutions has not been assessed in depth. This work investigates to which extent the incentives on different typologies of energy-efficiencymeasures can improve the performance of the optimal retrofits solutions. The analysis has been carried out on a set of different residential building modules, representative of different building typologies and Italian construction periods, located in two different climatic contexts representative of Italy, mixed-humid (Milano) and warm-marine (Messina) (ASHRAE 2007), optimizing the energy, costs, and indoor thermal comfort aspects
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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