| 1. |
- Allard, Ingrid, 1986-, et al.
(författare)
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Energy evaluation of residential buildings : Performance gap analysis incorporating uncertainties in the evaluation methods
- 2018
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Ingår i: Building Simulation. - : Tsinghua University Press. - 1996-3599 .- 1996-8744. ; 11:4, s. 725-737
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Tidskriftsartikel (refereegranskat)abstract
- Calculation and measurement-based energy performance evaluations of the same building often provide different results. This difference is referred as "the performance gap". However, a large performance gap may not necessarily mean that there are flaws in the building or deviations from the intended design. The causes for the performance gap can be analysed by calibrating the simulation model to measured data. In this paper, an approach is introduced for verifying compliance with energy performance criteria of residential buildings. The approach is based on a performance gap analysis that takes the uncertainties in the energy evaluation methods into consideration. The scope is to verify building energy performance through simulation and analysis of measured data, identifying any performance gap due to deviations from the intended design or flaws in the finished building based on performance gap analysis. In the approach, a simulation model is calibrated to match the heat loss coefficient of the building envelope [kWh/K] instead of the measured energy. The introduced approach is illustrated using a single-family residential building. The heat loss coefficient was found useful towards identifying any deviations from the intended design or flaws in the finished building. The case study indicated that the method uncertainty was important to consider in the performance gap analysis and that the proposed approach is applicable even when the performance gap appears to be non-existing.
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| 2. |
- Bee, Elena, et al.
(författare)
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Air-source heat pump and photovoltaic systems for residential heating and cooling : Potential of self-consumption in different European climates
- 2019
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Ingår i: Building Simulation. - : Springer Science and Business Media LLC. - 1996-3599 .- 1996-8744. ; 12:3, s. 453-463
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Tidskriftsartikel (refereegranskat)abstract
- Renewable sources will play a key role in meeting the EU targets for 2030. The combined use of an aerothermal source through a heat pump and a solar source with a photovoltaic (PV) system is one feasible and promising technology for the heating and cooling of residential spaces. In this study, a detailed model of a single-family house with an air-source heat pump and a PV system is developed with the TRNSYS simulation software. Yearly simulations are run for two types of buildings and nine European climates, for both heating and cooling (where needed), in order to have an overview of the system behaviour, which is deeply influenced by the climate. The storage system (electrical and thermal) is also investigated, by means of multiple simulation scenarios, with and without the battery and with different water storage sizes. The numerical results provide an overview of the performance of the considered heating and cooling system, as well as the balance of the electrical energy exchange between the grid, the building, and the PV array.
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| 3. |
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| 4. |
- Davoodi, Anahita, 1979-, et al.
(författare)
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The use of lighting simulation in the evidence-based design process : A case study approach using visual comfort analysis in offices
- 2020
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Ingår i: Building Simulation. - : Springer. - 1996-3599 .- 1996-8744. ; 13:1, s. 141-153
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Tidskriftsartikel (refereegranskat)abstract
- The EBD-SIM (evidence-based design, simulation) framework is a conceptual framework developed to integrate the use of lighting simulation in the EBD process to provide a holistic performance evaluation method. A real-time case study, executed in a fully operational office building, is used to demonstrate the framework’s performance. The case study focused on visual comfort analysis. The objective is to demonstrate the applicability of the developed EBD-SIM framework using correlations between current visual comfort metrics and actual human perception as evaluation criteria. The data were collected via simulation for visual comfort analysis and via questionnaires for instantaneous and annual visual comfort perception. The study showed that for user perception, the most crucial factor for visual comfort is the amount of light on a task area, and simple metrics such as Eh-room and Eh-task had a higher correlation with perceived visual comfort than complex performance metrics such as Daylight Autonomy (DA). To improve the design process, the study suggests that, among other things, post-occupancy evaluations (POEs) should be conducted more frequently to obtain better insight into user perception of daylight and subsequently use new evidence to further improve the design of the EBD-SIM model.
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| 5. |
- Domhagen, Fredrik, 1987, et al.
(författare)
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Impact of weather conditions and building design on contaminant infiltration from crawl spaces in Swedish schools—Numerical modeling using Monte Carlo method
- 2022
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Ingår i: Building Simulation. - : Springer Science and Business Media LLC. - 1996-8744 .- 1996-3599. ; 15:5, s. 845-858
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Tidskriftsartikel (refereegranskat)abstract
- Some Swedish school buildings built in the 1960s and 1970s experience indoor air quality problems, where the contaminants are suspected to come from the crawl space underneath the building. The poor indoor air quality causes discomfort among pupils and teachers. Installing an exhaust fan to maintain a negative pressure difference in the crawl space relative to indoors or increasing the ventilation in the classroom are two examples of common measures taken to improve the indoor air quality. However, these measures are not always effective, and sometimes the school building has to be demolished. The relation between pressure distribution, contaminant concentration in the classroom, outdoor temperature, wind, mechanical ventilation, and air leakage distribution is complex. A better understanding of these relations is crucial for making decisions on the most efficient measure to improve the indoor air quality. In this paper, a model for contaminant infiltration from the crawl space is used together with the Monte Carlo method to study these relations. Simulations are performed for several cases where different building shapes, building orientations, shielding conditions, and geographical locations are simulated. Results show, for example, that for a building with an imbalanced ventilation system, air is leaking from the crawl space to the classroom for the majority of cases and that concentration levels in the classroom are usually the highest during mild and calm days.
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| 6. |
- Fong, K. F., et al.
(författare)
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Residential building performance analysis at near extreme weather conditions in Hong Kong through a thermal-comfort-based strategy
- 2023
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Ingår i: Building Simulation. - : Springer Nature. - 1996-3599 .- 1996-8744. ; 16, s. 13-25
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Tidskriftsartikel (refereegranskat)abstract
- The precise building performance assessment of residential housings in subtropical regions is usually more difficult than that for the commercial premises due to the much more complicated behavior of the occupants with regard to the change in indoor temperature. The conventional use of a fixed schedule for window opening, clothing insulation and cooling equipment operation cannot reflect the real situation when the occupants respond to the change in thermal comfort, thus affecting the appropriateness of the assessment results. To rectify the situation, a new modeling strategy in which the modification of the various operation schedules was based on the calculated thermal comfort (TC), was developed in this study. With this new TC-based strategy, the realistic building performances under different cooling provision scenarios applied to a high-rise residential building under the near extreme weather conditions were investigated and compared. It was found that sole provision of ventilation fans could not meet the zone thermal comfort by over 68% of the time, and air-conditioning was essential. The optimal use of ventilation fans for cooling could only help reduce the total cooling energy demand by less than 12% at best which could only be realistically evaluated by adopting the present strategy. Parametric studies were conducted which revealed that some design factors could offer opportunities for reducing the total cooling energy under the near extreme weather conditions.
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| 7. |
- Goto, Yutaka, 1984, et al.
(författare)
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Heat and moisture balance simulation of a building with vapor-open envelope system for subtropical regions
- 2012
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Ingår i: Building Simulation. - : Springer Science and Business Media LLC. - 1996-8744 .- 1996-3599. ; 5:4, s. 301-314
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Tidskriftsartikel (refereegranskat)abstract
- Global warming and the resource depletion induced discussions on sustainable developments within the construction sector. Also the rapid urbanization in subtropical regions is becoming one of the most important global issues. Appropriate measures must be taken in such developments to avoid further damage to the environment. In this study, the heat and moisture balance simulation of building with a sustainable building envelope system for subtropical climate was proposed. In the moisture balance simulation the moisture buffering by the interior materials was taken into account. The prediction of moisture buffer value (MBV) of the interior finishing materials was attempted and validated by measurements. Subsequently, the whole building calculation was carried out and the contribution of the moisture buffering to the indoor comfort and energy consumption was investigated. The MBVs of the mineral-based materials were predicted with high accuracy. However, that of wood-based composite was much higher than the experimental value. In order to create a more accurate model, nonlinear moisture conductance should be accounted when modeling wood-based materials. The heating and cooling demand of a test house was 9.4 kWh/m2 and 14.5 kWh/m2, respectively. It was concluded that the utilization of the building envelope system has a high potential to provide sustainable houses in subtropical regions. In order to enhance both energy efficiency and indoor comfort of buildings in subtropical regions, there still is a strong need to develop a holistic method to find the optimum building design considering not only moisture buffering but also all the relevant factors. The presented model will be validated by in-situ measurements in the near future.
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| 8. |
- Haghshenas, Samira, et al.
(författare)
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Multi-Objective Optimization of Impinging Jet Ventilation Systems: Taguchi Based CFD Method
- 2018
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Ingår i: Building Simulation. - : Springer Science and Business Media LLC. - 1996-3599 .- 1996-8744. ; 11:6, s. 1207-1214
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a Taguchi method-based approach that can optimize the operating performance of impinging jet ventilation (IJV) systems with limited computational fluid dynamics (CFD) simulation results. The Taguchi optimization calculation finds the best operating design for the weighted overall objective function as a presenter of the multi-objective function problem. The method is used to optimize the operating characteristics of an IJV system considering the factors of supply air temperature, level of the return air vent and percentage of the air exhausted through the ceiling to achieve an overall best performance of thermal comfort, indoor air quality (IAQ) and system energy performance as the objective functions. The study indicates the contribution percentage for each factor in each objective function. The level of the return air vent, the supply air temperature, and the percentage of air exhausted through the ceiling have a contribution of 35.8%, 28.5%, and 35.8% in the objective functions, respectively. Based on the results, the best performance of the IJV system happens when the inlet air temperature is 18 °C, the height of the return air vent is 2 m above the floor, and the percentage of air exhausted through the ceiling is 22.5%.
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| 9. |
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| 10. |
- Li, Pin, et al.
(författare)
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CFD modeling of dynamic airflow and particle transmission in an aircraft lavatory
- 2023
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Ingår i: Building Simulation. - : Springer Nature. - 1996-3599 .- 1996-8744. ; 16:8, s. 1375-1390
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Tidskriftsartikel (refereegranskat)abstract
- Lavatories are frequently used facilities, especially on long-haul flights. Flushing a vacuum toilet in a lavatory can induce strong airflow, produce aerosols in the toilet bowl, and resuspend deposited particles from the floor. However, the exact particle transport routes and the fates of particle after toilet flushing are unclear so far. This investigation used computational fluid dynamics (CFD) to model the transient airflow and pollutant transport after a toilet flushing process in a lavatory of a commercial aircraft. The time-varying pressure profile measured in a laboratory was assigned to the drainage valve as boundary conditions. The aerosols generated inside the toilet bowl during flushing and the particles resuspended from the lavatory floor were used as particle sources. Lagrangian tracking of airborne particles in the lavatory was conducted. In addition, ammonia gas was used to examine odor perception. The multi-physics software program COMSOL 5.4 was employed for numerical solution after being validated. The results revealed that more than 70% of the generated particles in the toilet bowl are drained into sewage. A few particles may leak out of the toilet bowl and remain suspended in the air for more than five minutes when the toilet lid is open during flushing. Flushing the toilet with a closed lid can effectively reduce the particle leakage and the spread of odor gas, but it leads to greater deposition of particles on both the lid and seat. There is a slight inhalation exposure risk in the initial three minutes after flushing with a closed lid.
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