| 1. |
- De Coninck, Roel, et al.
(författare)
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Toolbox for development and validation of grey-box building models for forecasting and control
- 2016
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Ingår i: Journal of Building Performance Simulation, Taylor & Francis. - : Informa UK Limited. - 1940-1507 .- 1940-1493. ; 9:3, s. 288-303
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Tidskriftsartikel (refereegranskat)abstract
- As automatic sensing and information and communication technology get cheaper, building monitoring data becomes easier to obtain. The availability of data leads to new opportunities in the context of energy efficiency in buildings. This paper describes the development and validation of a data-driven grey-box modelling toolbox for buildings. The Python toolbox is based on a Modelica library with thermal building and Heating, Ventilation and Air-Conditioning models and the optimization framework in JModelica.org. The toolchain facilitates and automates the different steps in the system identification procedure, like data handling, model selection, parameter estimation and validation. To validate the methodology, different grey-box models are identified for a single-family dwelling with detailed monitoring data from two experiments. Validated models for forecasting and control can be identified. However, in one experiment the model performance is reduced, likely due to a poor information content in the identification data set.
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| 2. |
- Filipsson, Peter J, 1985, et al.
(författare)
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Modelling of rooms with active chilled beams
- 2020
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Ingår i: Journal of Building Performance Simulation. - : Informa UK Limited. - 1940-1493 .- 1940-1507. ; 13:4, s. 409-418
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Tidskriftsartikel (refereegranskat)abstract
- Active chilled beams (ACBs) are often modelled as generic cooling devices. Due to induction, the air flow discharged from an ACB is several times higher than supplied from the air handling unit, and due to its design, it affects the temperature of the ceiling to a greater extent than an arbitrary cooling device. This paper investigates the impact of taking these features into account when simulating air and operative temperature in a room equipped with an ACB. The building performance simulation software IDA ICE is used for analysis and the simulations are compared with full-scale experiments. The main findings are that simulations which take into account the features mentioned above correspond more closely with measurements. If designing for a certain operative temperature, this reduces the required design cooling capacity. Although negligible in many applications, the magnitude of this reduction is 9% with high-temperature cooling.
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| 3. |
- Gonzalez Caceres, Alex Arnoldo, 1982, et al.
(författare)
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Towards digital twinning for multi-domain simulation workflows in urban design: a case study in Gothenburg
- 2024
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Ingår i: Journal of Building Performance Simulation. - 1940-1493 .- 1940-1507. ; In Press
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Tidskriftsartikel (refereegranskat)abstract
- This work proposes an automated workflow using digital twinning for multi-domain environmental performance analysis of urban developments. Digital twins can potentially provide a common basis for multi-domain simulations and help overcome data availability and interoperability issues. The proposed workflow consists of five steps: (1) creating a procedural urban 3D model, (2) generating design alternatives parametrically, (3) exporting the context and each design alternative to each simulation tool, (4) running simulations for wind comfort, energy demand, and noise for each design alternative, and (5) combining and visualizing the simulation results using the digital twin. The workflow was applied to a neighbourhood in Sweden, the resultsreveal significant reduction in manual work when applying multiple simulation software for different domains. This is one step forward in streamlining the workflow for urban analysis, crucial for multi-domain optimization. In the future, further domains and simulation tools can be added to the workflow.
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| 4. |
- Haller, M., et al.
(författare)
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A Unified Model for the Simulation of Oil, Gas, and Biomass Space Heating Boilers for Energy Estimating Purposes : Part II: Parameterization and Comparison with Measurements
- 2011
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Ingår i: Journal of Building Performance Simulation, Taylor & Francis. - : Taylor & Francis. - 1940-1493 .- 1940-1507. ; 4:1, s. 19-36
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Tidskriftsartikel (refereegranskat)abstract
- A semi-physical model for the simulation of oil, gas and biomass space heating boilers has been parameterized based on measurements on nine different boiler units and simulation results have been compared to results obtained from measurements in steady state and transient operation. Although the agreement between simulated and measured boiler efficiencies was within the range of measurement uncertainties in most cases, model improvements are expected to be possible concerning the heat capacitance modelling in cycling on/off operation as well as influences of start and stop behaviour on the overall efficiency. It is found that electricity consumption during cycling on/off operation of small pellets or oil space heating boilers may have a significant influence on the overall energy balance of these units. This influence increases strongly with decreasing heat load and increasing number of on/off cycles.
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| 5. |
- Haller, M., et al.
(författare)
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A Unified Model for the Simulation of Oil, Gas, and Biomass Space Heating Boilers for Energy Estimating Purposes : Part I: Model Development
- 2011
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Ingår i: Journal of Building Performance Simulation, Taylor & Francis. - : Taylor & Francis. - 1940-1493 .- 1940-1507. ; 4:1, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- A unified model for the simulation of oil, gas, pellet and wood chip space heating boilers for energy estimating purposes has been developed based on a literature review and laboratory measurements on four different boilers. The model includes the influence of space heating return temperature, power modulation and condensation gains on the flue gas losses of the boiler, the simulation of a thermal boiler capacitance including its heat losses during standby and operation, and the ability to calculate carbon monoxide emissions and electricity use dependent on power modulation and number of burner starts. Some of the new features of the presented boiler model are the unification of models for oil, gas and biomass boilers into one model, and the combination of steady state calculation for the flue gas to water heat transfer with an explicit solution for the time dependent temperature change of the boiler’s thermal capacitance.
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| 6. |
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| 7. |
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| 8. |
- Johansson, Dennis, et al.
(författare)
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Simulating space heating demand with respect to non-constant heat gains from household electricity
- 2011
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Ingår i: Journal of Building Performance Simulation, Taylor & Francis. - : Informa UK Limited. - 1940-1507 .- 1940-1493. ; 4:3, s. 227-238
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Tidskriftsartikel (refereegranskat)abstract
- It is crucial to perform energy simulations during the building process to design a building that meets requirements regarding low energy use. In a low energy building, internal heat gains such as excess heat from household electricity are a large part of the heat balance of the building. The internal heat gains depend on the occupants and are not constant, although they are often assumed constant in simulations of space heating demand. This article analyses how different usage patterns of household electricity affects simulated space heating demand. Parametric studies of energy use-related parameters were done to study the influence from different designs. The results show that the different energy use patterns affect the space heating demand, especially in low energy buildings and during the colder parts of the year. To make accurate energy simulations of low energy buildings, household electricity use patterns should be taken into account.
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| 9. |
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| 10. |
- Ochoa, Carlos E., et al.
(författare)
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State of the art in lighting simulation for building science : A literature review
- 2012
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Ingår i: Journal of Building Performance Simulation, Taylor & Francis. - : Informa UK Limited. - 1940-1493 .- 1940-1507. ; 5:4, s. 209-233
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Forskningsöversikt (refereegranskat)abstract
- This paper examines the current state of the art in lighting simulation related to building science research. Discussion on historical developments and main modelling approaches is followed by describing lighting simulation within the design process, where it is applied beyond presentation renderings. Works are grouped using the main aspects of a program (input, modelling and output). Lighting simulation currently focuses on representing accurately a large number of common situations encountered by building designers and researchers. Existing models apply roughly the same theoretical algorithms and calculation aids, limiting representation of certain physical phenomena. Although some models can be used for element design, they are not practical enough to develop or prototype new, untested elements. Elaborate building components require separate analysis through complex simulation aids. Few tools support the early architectural design process. Simplification applies when integrating lighting simulation to wholebuilding simulation. Input quality affects accuracy, while output needs careful expert interpretation.
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| 11. |
- Puttige, Anjan Rao, 1990-, et al.
(författare)
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Improvement of borehole heat exchanger model performance by calibration using measured data
- 2020
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Ingår i: Journal of Building Performance Simulation, Taylor & Francis. - : Taylor & Francis. - 1940-1493 .- 1940-1507. ; 13:4, s. 430-442
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Tidskriftsartikel (refereegranskat)abstract
- Planning the operation of large ground source heat pump (GSHP) systems requires accurate models of borehole heat exchangers (BHEs) that are not computationally intensive. In this paper, we propose parameter estimation using measured data as a method to improve the analytical models of BHE. The method was applied to a GSHP system operating for over 3 years. The deviation between modelled and measured load of the BHE reduced from 22% to 14%. Influence of the calibration data set was tested by changing time resolution and season of the calibration data. We concluded that the time resolution must be high enough to differentiate among the effects of different parameters and that different model parameters must be used for injection and extraction (seasons). The method was also applied to a GSHP that has been monitored for 10 years, which showed that accuracy of the model can be improved by annual updates of parameters.
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| 12. |
- Sasic Kalagasidis, Angela, 1968
(författare)
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A multi-level modelling and evaluation of thermal performance of phase change materials in buildings
- 2014
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Ingår i: Journal of Building Performance Simulation. - : Informa UK Limited. - 1940-1493 .- 1940-1507. ; 7:4, s. 289-308
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Tidskriftsartikel (refereegranskat)abstract
- Integration of phase-change materials (PCMs) in building envelopes is a way to enhance heat storage capacity of buildings and thereby to rationalize the use of energy for heating and cooling of buildings. This work presents a numerical model of a building envelope with PCMs, verifications of the model according to a normative benchmark and measurements and a tentative case study that exemplifies the effects of such a building envelope on the thermal performance of a whole building. Simulations have been carried out using a modular environment of the International Building Physics Toolbox in Simulink®. As for the effects of PCMs in buildings, it is concluded that they are rather case sensitive; in the tentative case study, the annual savings of total energy for heating and cooling vary between 5% and 21%, depending mainly on the thermal comfort and the placement of PCM in the building envelope.
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| 13. |
- Vesterberg, Jimmy, 1976-, et al.
(författare)
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Calibration of low-rise multifamily residential simulation models using regressed estimations of transmission losses
- 2016
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Ingår i: Journal of Building Performance Simulation, Taylor & Francis. - : Informa UK Limited. - 1940-1493 .- 1940-1507. ; 9:3, s. 304-315
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we evaluated a proposed calibration approach for whole-building energy simulation models. This approach was based on a regression analysis of measured data collected during a time period when the global solar radiation was the lowest. The proposed approach was compared with a more conventional calibration approach with different degrees of complexity, starting from design stage assumptions, through audits, and lastly by refining the model with detailed measurements and numerical calculations. The evaluation was performed using measured data from two multifamily buildings located in Umeå, Sweden, and the IDA ICE 4.61 simulation software. The best agreement between simulated and measured data was obtained with the proposed calibration approach. The monthly normalized mean bias error and the coefficient of variation was less than 5.0% and 6.0% respectively. For the conventional calibration approach, detailed measurements and time-consuming numerical calculations were required to reach similar results.
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| 14. |
- Widén, Joakim, 1980-, et al.
(författare)
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Models of domestic occupancy, activities and energy use based on time-use data : deterministic and stochastic approaches with application to various building-related simulations
- 2012
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Ingår i: Journal of Building Performance Simulation, Taylor & Francis. - : Informa UK Limited. - 1940-1493 .- 1940-1507. ; 5:1, s. 27-44
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Tidskriftsartikel (refereegranskat)abstract
- Time-use data (TUD) have a large potential for improving occupancy and load modelling and for introducing realistic behavioural patterns into various simulations. In this article, previously developed models of occupancy, activities and energy use based on TUD are extended and described in a general framework. Two extensions are studied: deterministic conversion of empirical TUD is extended into a complete thermal load model encompassing both occupancy and various end-uses and a Markov-chain approach for generating synthetic TUD sequences is extended to include a model for load management. Three examples of building-related applications are presented: simulation of indoor climate in a low-energy building, household electricity load management in response to time-differentiated electricity tariffs and simulations of load matching in a net zero energy building. The main conclusion is that the extended model framework can generate detailed and realistic behavioural patterns that allow diversity and correlations between end-uses to be taken into account.
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| 15. |
- Petersson, Bo
(författare)
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Putin and the Russian Mythscape : Dilemmas of Charismatic Legitimacy
- 2017
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Ingår i: Demokratizatsiya. - : IERES. - 1074-6846 .- 1940-4603. ; 25:3, s. 235-254
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Forskningsöversikt (refereegranskat)abstract
- For decades now, President Vladimir Putin has consistently enjoyed markedly high approval rates and seemingly benefitted from charismatic legitimacy, whereas systemic legal-rational legitimacy has remained on a low level. This article discusses how, through the successful communication of political myth, legitimacy has become ever more personalized in Putin’s Russia, and considers some of the dilemmas inherent in non-democratic settings where legitimacy builds on grounds that are not legal-rational in the Weberian sense.
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