Multi-room Building Research Articles

The Numerical Simulation Study of Pumping Airflow Driven by Wind Pressure for Single- and Multi-Room Buildings

Pumping airflow occurs in single-sided natural ventilation buildings when the openings are located on the leeward side; the direction of airflow through the building then changes periodicity. In order to propose a calculation method of the ventilation rates for single-room buildings and analyze the pumping ventilation for multi-room buildings, the CFD method with an SST k-ω turbulence model was used to conduct numerical simulation in this study, which is verified by other experimental results. Firstly, the qualitative and quantitative characteristics of pumping ventilation were investigated for a single-room building with two openings. The results show that the steady-state method underestimates the ventilation flow rates, and the unsteady-state method captures the microstructures of the flow better. Secondly, the vortex-shedding and indoor airflow oscillation frequencies were analyzed based on transient simulation for a single-room building. It was found that both of them increase with air speed. Then, the factors affecting ventilation flow rates were analyzed. A calculation method for dimensionless ventilation rates is proposed. Finally, the pumping ventilation for a multi-room building was numerically simulated. The ventilation rate for a middle room is greater than that for a corner room, and the ventilation rate for any room in a multi-room building is greater than the single-room building given the same room size and the same incoming wind speed. The findings of this paper are helpful for the design and evaluation of natural ventilation.

Comprehensive performance analysis of a rural building integrated PV/T wall in hot summer and cold winter region

The building-integrated PV/T technologies have garnered significant attention due to their considerable potential in low-carbon and zero-energy buildings. To gain deeper insights into the practical application of this technology, a comprehensive study was conducted on a rural building integrated with PV/T walls for demonstration purposes. A novel simulation approach, coupling the numerical models of the PV/T walls with the building energy software, was proposed and experimentally validated. Based on the validated simulation approach, this study investigated the comprehensive performance of the demo building and explored the optimal capacity of the energy storage system (ESS). The main findings are as follows: (1) The proposed simulation approach could accurately predict the energy behaviors of the multi-room building integrated PV/T wall. (2) The demo building with the optimized EES yielded 1355.32 kWh of clean electricity and 455.3 kWh of heat gain for water heating, while reducing cooling and heating loads by 5% and 12%, respectively. (3) The optimal azimuth for the building in the studied region was 45°, and the total energy benefits of the building decreased by 28.5% with an increase in dust density from 0 g/m2 to 10 g/m2.

Geophysical Investigations within the Latus Dextrum of Porolissum Fort, Northwestern Romania—The Layout of a Roman Edifice

This paper summarizes the results of a recent geophysical investigation carried out at Porolissum, which is considered to be one of the most significant Roman sites in Romania. The geophysical survey was carried out within the latus dextrum of the fort, which is the same location that had been the subject of earlier geophysical surveys as well as older archaeological excavations (1970s) that had uncovered a multiroom building. A cesium vapor total field magnetometer and a multi-electrode resistivity meter for a dense Electrical Resistivity Tomography (ERT) survey were used. Eighty parallel ERT profiles in combination with the emerging total field magnetic data and an antecedent magnetic survey allowed us to complete a more precise interpretation regarding the building that once existed on the left side of Porolissum’s Principia (the commander’s house). In contrast to the magnetic survey, which only reveals a part of the building’s architecture, the ERT survey provides a comprehensive view of the structure’s layout. More than 20 rooms could be positively identified, and the existence of further rooms might be deduced from the data. The ERT scan revealed the existence of the building’s northern external wall as well, which is not reflected on the magnetic map. Because some parts of the building are not visible on the magnetic map, we can assume that the building was constructed with at least two types of rocks (magmatic and sedimentary). In addition to the archaeological interpretation of the geophysical anomalies, a number of discussions concerning the connection between our survey and the geology of the area were held. The complementarity of the magnetic and resistivity results prompted us to conceive a preliminary 3D reconstruction of the building. Even if the building function is unknown in the absence of reliable archaeological data, it could have been a storage building, a second praetorium, a valetudinarium (hospital), or an armamentarium (weapons storage building). The illustrative reconstruction was completed taking into consideration that the building was a Roman military hospital, which, based on the available data, may be considered a credible assumption.

Creative Hubs in Hanoi, Vietnam

Creative Hubs in Hanoi, Vietnam

Domestic risk factors for increased rodent abundance in a Lassa fever endemic region of rural Upper Guinea

Lassa fever (LF) is a viral haemorrhagic fever endemic in West Africa and spread primarily by the multimammate rat, Mastomys natalensis. As there is no vaccine, reduction of rodent-human transmission is essential for disease control. As the household is thought to be a key site of transmission, understanding domestic risk factors for M. natalensis abundance is crucial. Rodent captures in conjunction with domestic surveys were carried out in 6 villages in an area of rural Upper Guinea with high LF endemicity. 120 rodent traps were set in rooms along a transect in each village for three nights, and the survey was administered in each household on the transects. This study was able to detect several domestic risk factors for increased rodent abundance in rural Upper Guinea. Regression analysis demonstrated that having > 8 holes (RR = 1.8 [1.0004–3.2, p = 0.048), the presence of rodent burrows (RR = 2.3 [1.6–3.23, p = 0.000003), and being in a multi-room square building (RR = 2.0 [1.3–2.9], p = 0.001) were associated with increased rodent abundance. The most addressable of these may be rodent burrows, as burrow patching is a relatively simple process that may reduce rodent entry. Further study is warranted to explicitly link domestic rodent abundance to LF risk, to better characterize domestic risk factors, and to evaluate how household rodent-proofing interventions could contribute to LF control.

Investigation of potential aerosol transmission and infectivity of SARS-CoV-2 through central ventilation systems

The COVID-19 pandemic has raised concern of viral spread within buildings. Although near-field transmission and infectious spread within individual rooms are well studied, the impact of aerosolized spread of SARS-CoV-2 via air handling systems within multiroom buildings remains unexplored. This study evaluates the concentrations and probabilities of infection for both building interior and exterior exposure sources using a well-mixed model in a multiroom building served by a central air handling system (without packaged terminal air conditioning). In particular, we compare the influence of filtration, air change rates, and the fraction of outdoor air. When the air supplied to the rooms comprises both outdoor air and recirculated air, we find filtration lowers the concentration and probability of infection the most in connected rooms. We find that increasing the air change rate removes virus from the source room faster but also increases the rate of exposure in connected rooms. Therefore, slower air change rates reduce infectivity in connected rooms at shorter durations. We further find that increasing the fraction of virus-free outdoor air is helpful, unless outdoor air is infective in which case pathogen exposure inside persists for hours after a short-term release. Increasing the outdoor air to 33% or the filter to MERV-13 decreases the infectivity in the connected rooms by 19% or 93% respectively, relative to a MERV-8 filter with 9% outdoor air based on 100 quanta/h of 5 μm droplets, a breathing rate of 0.48 m3/h, and the building dimensions and air handling system considered.

Monumental Structures of Bilyar: new approach. Buildings with Underfloor Heating

The article discusses the monumental buildings of Bilyar, located in the citadel of the fortified settlement. Great mosque of Bilyar and other public buildings were investigated in the 70s of XX century. At the same time their reconstruction, which became canonical were made. Consideration of Bilyar buildings in the context of the architecture of the entire Muslim world makes it possible to make some adjustments both in the interpretation of buildings and in the elements of their reconstruction. The building with underfloor heating near the Juma mosque was considered the house of a feudal lord and was reconstructed as a two-story domed building. Another multi-room building with heated floors was interpreted as a caravanserai. Underfloor heating, plastering floors and walls with a water-resistant mortar, and a water drainage system indicate that these buildings were public baths. Like all eastern baths, they had one floor and were multi-domed buildings.

Dispersion Characteristics of Hazardous Gas and Exposure Risk Assessment in a Multiroom Building Environment.

The leakage of hazardous chemicals during storage and transport processes is a kind of commonly occurring accident that can pose a serious threat to people’s lives and property. This paper aims to investigate the airflow and dispersion characteristics of hazardous gas around a multiroom building, and evaluate the corresponding exposure risks. The effects on indoor air quality (IAQ) when polluted air enters a room under different indoor and external conditions were examined by using a computational fluid dynamics technique. First, the numerical model established herein was verified by the available wind-tunnel experimental data, and acceptable agreement was found between the predicted and measured velocities. Subsequently, the effects of different natural ventilation paths, wall porosities and outdoor pollutant source characteristics on the airflow and contaminant distribution were evaluated. The study not only reveals the airflow pattern and concentration distribution in indoor spaces under different natural ventilation conditions but also quantitatively analyzes the relationship between the probability of death and the corresponding source strength under the circumstance of pollutant leakage near a building. The results can be useful for the prevention and control of hazardous chemical gas leakages and provide some guidance on evacuation after an accidental or routine leakage.

Experimental study of airflow and pollutant dispersion in cross-ventilated multi-room buildings: Effects of source location and ventilation path

Indoor air quality (IAQ) problem and associated health risks, determined by the indoor air pollutant, are of great concern in modern society. This paper presents a detailed experimental study of pollutant dispersion and airflow characteristics in a multi-room building under cross ventilation condition. A series of experiments were conducted in a scaled multi-room chamber which represents a slap-shaped building. A wind wall system was developed to simulate the cross-ventilated environment. The windows and doors were used as cross ventilation openings, enabling three ventilation path test scenarios. Tracer gas technique was employed to reveal the pollutant dispersion features in the chamber under different conditions. Both the air velocities and tracer gas concentrations at selected key positions in the chamber were measured. The mean concentration values were analyzed to investigate the influence of source location and ventilation path on the pollutant dispersion. This study shows that the pollutant dispersion and airflow characteristics can be strongly influenced by the source location and the ventilation path under approximately the same inflow conditions, and the differences were quantitatively presented. The results give useful insights into the airflow pollutant dispersion process in cross-ventilated multi-room buildings and provide a valuable database for the validation of CFD simulations.

Fractional-Derivative Approximation of Relaxation in Complex Systems

In this paper, we present a system identification (SI) procedure that enables building linear time-dependent fractional-order differential equation (FDE) models able to accurately describe time-dependent behavior of complex systems. The parameters in the models are the order of the equation, the coefficients in it, and, when necessary, the initial conditions. The Caputo definition of the fractional derivative, and the Mittag-Leffler function, is used to obtain the corresponding solutions. Since the set of parameters for the model and its initial conditions are nonunique, and there are small but significant differences in the predictions from the possible models thus obtained, the SI operation is carried out via global regression of an error-cost function by a simulated annealing optimization algorithm. The SI approach is assessed by considering previously published experimental data from a shell-and-tube heat exchanger and a recently constructed multiroom building test bed. The results show that the proposed model is reliable within the interpolation domain but cannot be used with confidence for predictions outside this region. However, the proposed system identification methodology is robust and can be used to derive accurate and compact models from experimental data. In addition, given a functional form of a fractional-order differential equation model, as new data become available, the SI technique can be used to expand the region of reliability of the resulting model.

散水屋根面のある多数室室温計算の簡易化と散水の熱的効果に関する研究 : 第1報-計算法の概要

散水屋根面のある多数室室温計算の簡易化と散水の熱的効果に関する研究 : 第1報-計算法の概要

散水屋根面のある多数室室温計算の簡易化と散水の熱的効果に関する研究 : 第2報-熱的効果と簡易計算法の評価

散水屋根面のある多数室室温計算の簡易化と散水の熱的効果に関する研究 : 第2報-熱的効果と簡易計算法の評価

Real-Time Forecasting of Building Fire Growth and Smoke Transport via Ensemble Kalman Filter

Forecasting building fire growth and smoke dispersion is a challenging task but can provide early warnings to first responders and building occupants and thus significantly benefit active building fire protection. Although existent computer simulation models may provide acceptable estimations of smoke temperature and quantity, most simulations are still not able to achieve real-time forecast of building fire due to high computational requirements, and/or simulation accuracy subject to users’ inputs. This paper investigates one of the possibilities of using ensemble Kalman filter (EnKF), a statistical method utilizing the real-time sensor data from thermocouple trees in each room, to estimate the spread of an accidental building fire and further forecast smoke dispersion in real time. A general approach to forecasting building fire and smoke is outlined and demonstrated by a 1:5 scaled compartment fire experiment using a 1.0 kW to 2.8 kW propane burner as fire source. The results indicate that the EnKF method is able to forecast smoke transport in a multi-room building fire using 40 ensemble members and provide noticeable accuracy and lead time. Unlike other methods that directly use measurement data as model inputs, the developed model is able to statistically update model parameters to maintain the forecasting accuracy in real time. The results obtained from the model can be potentially applied to assist mechanical smoke removal, emergency evacuation and firefighting.

Numerical analysis of propane dispersion under continuous release condition in a multi‐room building

Propane dispersion after the continuous leaking in the residential building is numerically simulated with FLUENT by computational fluid dynamic method. The variation characteristics of the concentration contribution and explosive range of propane are analyzed. The propane diffusion scope and explosive area increase with time. The highest concentration appears in the kitchen while the lowest concentration appears in the bedroom. Propane explosive area appears only in the kitchen and in the sunroom. Obvious stratification of the propane over the vertical height is due to gravity. The concentration, diffusion scope, and explosive area decrease with the number of windows open. The explosive range appears in the kitchen and the sunroom, but does not appear in the bedroom, the living room, or the bathroom. The research results can provide scientific support and references for risk evaluation, accident prevention and emergency rescue of propane hazards in the building. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 973–981, 2015

빌딩 내의 공기유동량 예측을 위한 누입 및 환기모델의 개발

A ventilation model was developed for predicting the air change per hour(ACH) in buildings and the airflow rates between zones of a multi-room building. In this model, the important parameters used in the calculation of airflow are wind velocity, wind direction, terrain effect, shielding effect by surrounding buildings, the effect of the window type and insect screening, etc. Also, the resulting set of mass balance equations required for the process of calculation of airflow rates are solved using a Conte-De Boor method. When this model was applied to the building which had been tested by Chandra et al.(1983), the comparison of predicted results by this study with measured results by Chandra et al. indicated that their variations were within -10%~+12%. Also, this model was applied to a building with five zones. As a result, when the wind velocity and direction did not change, terrain characteristics influenced the largest and window types influenced the least on building ventilation among terrain characteristics, local shieldings, and window types. Except for easterly and westerly winds, the ACH increased depending on wind velocity. The wind direction had influence on the airflow rates and directions through openings in building. Thus, this model can be available for predicting the airflow rates within buildings, and the results of this study can be useful for the quantification of airflow that is essential to the research of indoor air quality(temperature, humidity, or contaminant concentration) as well as to the design of building with high energy efficiency.

Relay Deployment in Cellular Networks: Planning and Optimization

This paper presents closed-form capacity expressions for interfere-limited relay channels. Existing theoretical analysis has primarily focused on Gaussian relay channels, and the analysis of interference-limited relay deployment has been confined to simulation based approaches. The novel contribution of this paper is to consolidate on these approaches by proposing a theoretical analysis that includes the effects of interference and capacity saturation of realistic transmission schemes. The performance and optimization results are reinforced by matching simulation results. The benefit of this approach is that given a small set of network parameters, the researcher can use the closed-form expressions to determine the capacity of the network, as well as the deployment parameters that maximize capacity without committing to protracted system simulation studies. The deployment parameters considered in this paper include the optimal location and number of relays, and resource sharing between relay and base-stations. The paper shows that the optimal deployment parameters are pre-dominantly a function of the saturation capacity, pathloss exponent and transmit powers. Furthermore, to demonstrate the wider applicability of the theoretical framework, the analysis is extended to a multi-room indoor building. The capacity improvements demonstrated in this paper show that deployment optimization can improve capacity by up to 60% for outdoor and 38% for indoor users. The proposed closed-form expressions on interference-limited relay capacity are useful as a framework to examine how key propagation and network parameters affect relay performance and can yield insight into future research directions.

Decentralized Inverse Model for Estimating Building Fire Source Location and Intensity

A decentralized inverse approach based on Bayesian inference and Markov Chain Monte Carlo sampling is developed to estimate the location and intensity of building fires. Compared with the methods based only on sensor data or fire models, this approach has little limits on the complexity of building structures and can be performed in real time due to the combination of those two methods. Additionally, by dividing the building into several zones, each of which is capable of fire inversion based on its local sensor reading and/or together with neighbor sensor readings, the decentralized algorithm is more efficient and robust compared with the centralized model using all sensor data. Three cases are designed to test the model and investigate the influence of sensor data quality and quantity in a multiroom building. The estimation from the fire zone can match the actual values when sufficient sensor data are used. The closer a zone is to the fire source, the more accurate the result is. In addition, this paper also investigates the effects of systematic errors in simulation-modeled sensor data. In the zones near the fire, the predicted location can be accurately determined but the predicted intensity is sensitive to the systematic errors.

Uncertainty of Tenability Times in Multiroom Building Fires

Fire risk for building occupants is determined by the time required for safe egress and the time at which untenable conditions develop in building rooms or on the egress routes. In the present study, the CFAST zone model is applied to the simulation of fire development and smoke propagation in multiroom buildings, with the aim of studying the sensitivity of predicted tenability times and quantification of the uncertainties due to variability of the scenario parameters. The building geometries considered are (i) a single room with a door and a window, (ii) three rooms connected by a long corridor, and (iii) two-level configuration with two rooms on the lower floor connected by a vertical vent to a room on the upper floor. Sensitivity indices of the tenability times due to high temperature and smoke obscuration are analyzed. Distribution functions of the tenability times are presented and compared for different building rooms.

The Ptolemaic–Roman Cemetery at the Quesna Archaeological Area*

The 2007 season of the Minufiyeh Archaeological Survey commenced with a topographic survey at Quesna, and continued with the opening of two test trenches to evaluate the results of a magnetometry survey undertaken in 2006. These renewed investigations in 2007 were situated to the west of the mausoleum, and revealed burials of the Ptolemaic and Roman periods; these included simple pit burials, mud-brick burials, and ceramic coffins. The second trench was aimed at better understanding a rectangular structure adjoining the falcon necropolis in the west, and was successful in locating a multi-room mud-brick building with internal and external walls defined. The initial interpretation of this structure is that it served as an entrance building, originally with vaulted ceilings, which led beneath the ancient ground level and, it might be assumed, into the corridors of the falcon necropolis.

Experimental study on fire smoke movement in a multi-floor and multi-room building

Fire smoke movement of multi-floor and multi-room (MFMR) fire was studied at the model test building in State Key Laboratory of Fire Science (SKLFS). The ingredient, temperature, air pressure difference and air velocity of smoke were measured and analyzed. Meanwhile, the hazard of smoke ingredient to exposed occupants was analyzed based on the national standard, Occupational Exposure Limit for Hazardous Agents in the Workplace (GBZ2-2002). The experimental results showed that the maximum temperature difference in MFMR fire was located along the vertical height from the fire source. With the spreading and diffusion of smoke, the temperature of smoke layer would tend to be no difference. In the fire of woodpile and kerosene, the main smoke ingredients such as SO 2 , CO and CO 2 would first exceed human’s average physiological limit, while smoke ingredients such as NO and NO 2 would come behind. Because of the higher fluctuation range and frequency of air pressure difference of smoke in multi-layer building fire, the fire smoke would spread around everywhere of the passageway and made the human evacuation more difficult.