•Problems of technical condition of swimming pools and its evaluation.•The impact of ventilation on the safety and durability of swimming pool facilities.•Numerical methods (CFD) for evaluating the ...effectiveness of ventilation performance in swimming pool facilities, both for cases just designed and completed.•Comparison of numerically indicated threats to the durability of swimming pool structures and problems occurring.•Numerical testing (CFD) of ventilation performance is a valuable tool that allows you to accurately identify problems and threats to the durability of pool structures, both at the design stage and in actually operating pool facilities.
Swimming pools are characterized by high humidity, high temperature, an aggressive environment caused by disinfection processes, high energy consumption, and extensive technical infrastructure. As a result, these facilities are at high risk of damage, including structural damage, which can have catastrophic consequences in extreme cases. Adequate ventilation plays a critical role in natatoria. The technical condition of swimming pool facilities should be regularly inspected to ensure that they are safe for the public. Various techniques can be used for this purpose. In the present study, a numerical analysis of ventilation performance and an assessment of the risks associated with design and construction errors in the ventilation system were conducted in a swimming pool building with a volume of 116,280.7 m3 and a surface area of 20,188.6 m2 in north-eastern Poland. Two scenarios were analyzed: the performance of the originally designed ventilation system and the performance of the ventilation system installed in the examined facility. The analyses were conducted with the use of computational fluid dynamics (CFD) tools in the FloVent program. Air distribution was determined by measuring ventilation parameters and conducting smoke tests in analyzed natatorium, and the obtained data were consistent with the results of the numerical analysis. The analyzed scenarios were compared to identify the risks associated with inadequate ventilation in swimming pools. A significant decrease in air supply led to local increases in air velocity and worsened thermal comfort parameters in the real-world facility. In addition, the decrease in air supply induced changes in air distribution and prevented air streams from reaching all parts of the natatorium. Some areas were inadequately ventilated, and condensed water vapor settled on the building’s glass facade and the roof, posing a direct threat to structural elements. The results of the numerical analysis were congruent with on-site measurements, which indicates that CFD tools are highly useful for assessing ventilation systems in swimming pools. These tools can be used to analyze ventilation performance and optimize the proposed solutions already at the design stage. The applied tools enable designers to eliminate construction errors and optimize a building’s structural safety, performance, and energy efficiency.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Despite various preventive interventions, nosocomial cross-infection remains a significant challenge in healthcare facilities worldwide. Consequently, prolonged hospitalization, elevated healthcare ...costs, and mortality rates are major concerns. Proper ventilation has been identified as one of the possible interventions for reducing the risk of cross-infection between patients and healthcare workers in hospital wards by diluting infectious agents and their carrying particles. The use of air cleaners in conjunction with the ventilation system further reduces the concentration of indoor pathogens. This article presents a systematic review of the ventilation solutions employed in hospital wards where pathogen removal performance can be enhanced using air-cleaning techniques while maintaining the thermal comfort of patients and healthcare staff. We provide a comparative analysis of the performance of different ventilation strategies adopted in one-, two-, or multi-bed hospital wards. Additionally, we discuss the parameters that influence the aerosol removal efficiency of ventilation systems and review various air-cleaning technologies that can further complement the ventilation system to reduce contaminant concentrations. Finally, we review and discuss the impact of different ventilation strategies on the perceived thermal comfort of patients and healthcare workers. This study provides insights into the cross-contamination risks associated with various hospital ward setups and the vital role of the ventilation system in reducing the adverse effects of infection risk. The findings of this review will contribute to the development of effective ventilation solutions that ensure improved patient outcomes and the well-being of healthcare workers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Despite a myriad of technical advances in medical imaging, as well as the growing need to address the global impact of pulmonary diseases, such as asthma and chronic obstructive pulmonary disease, on ...health and quality of life, it remains challenging to obtain in vivo regional depiction and quantification of the most basic physiological functions of the lung—gas delivery to the airspaces and gas uptake by the lung parenchyma and blood—in a manner suitable for routine application in humans. We report a method based on MRI of hyperpolarized xenon-129 that permits simultaneous observation of the 3D distributions of ventilation (gas delivery) and gas uptake, as well as quantification of regional gas uptake based on the associated ventilation. Subjects with lung disease showed variations in gas uptake that differed from those in ventilation in many regions, suggesting that gas uptake as measured by this technique reflects such features as underlying pathological alterations of lung tissue or of local blood flow. Furthermore, the ratio of the signal associated with gas uptake to that associated with ventilation was substantially altered in subjects with lung disease compared with healthy subjects. This MRI-based method provides a way to quantify relationships among gas delivery, exchange, and transport, and appears to have significant potential to provide more insight into lung disease.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Surface westerly winds in the Southern Hemisphere have intensified over the past few decades, primarily in response to the formation of the Antarctic ozone hole, and there is intense debate on the ...impact of this on the ocean's circulation and uptake and redistribution of atmospheric gases. We used measurements of chlorofluorocarbon-12 (CFC-12) made in the southern oceans in the early 1990s and mid- to late 2000s to examine changes in ocean ventilation. Our analysis of the CFC-12 data reveals a decrease in the age of subtropical subantarctic mode waters and an increase in the age of circumpolar deep waters, suggesting that the formation of the Antarctic ozone hole has caused large-scale coherent changes in the ventilation of the southern oceans.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
This study contains an analysis of indoor air quality in an office building. The analysis was carried out in real conditions. The purpose of conducted research was to determine façade-mounted ...ventilation unit efficiency to reduce pollution. The air was supply and exhaust from the room cycles lasting 2 min, 4 min and 10 min. The experimental research and calculation with use of tracer gas were conducted for determination of the air change rate. Carbon dioxide was used as tracer gas. The results of completed studies and calculations have shown that decentralised façade ventilation systems sufficiently reduces the concentration of gaseous pollutants. They keep the room temperature in the range of 21–22 °C and the relative humidity 28–39%. Cyclic air supply and exhaust guarantees hourly air change rate sufficient to dilute pollution. For the shortest cycle the experimental value of the air change rate equalled 2.3 h−1, and the calculated value equalled 2.2 h−1. For the longest cycle both values equalled 2.7 h−1. The conducted statistical analysis showed that the greatest average feature value of the reduction characteristic (reduction of carbon dioxide concentration) can be expected for the setting characteristic (lasting time of cycle) 10 min.
•Decentralised, façade ventilation units keep air temperature in range 21,2–22 °C.•Cyclic air supply and exhaust allow for obtaining the proper air exchange rate.•Measurement of air flow confirm calculated values of ACR with using tracer gas.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ
•A novel automated real-time model-based fault detection method is presented.•The proposed FDD method is used to identify abnormal performance in ventilation units.•Simulations of a dynamic energy ...performance model were used as a reference.•The method is implemented and evaluated in a case study university building.•The method implementation shows satisfactory results.
Studies show that buildings are able to attain energy savings of up to 30% by rectifying faulty HVAC systems using fault detection and diagnostic methods. In this study, we propose an automated top-down model-based fault detection method that can detect abnormal electricity consumption of building ventilation systems. This is achieved by employing a dynamic building model of the highly efficient OU44 teaching building at the University of Southern Denmark in Odense, allowing for identification and quantification of sub-optimal performance in real-time. The methodology is based on a statistical definition of abnormal telecommunicational operation that employs an approximation of the Chernoff bound proposed by Cheung et al. We develop and implement the Chernoff bound method for building ventilation systems and propose a simple approach of defining threshold limits based on a percentage of the model predicted performance of the ventilation systems. Each time the observed data deviates from the threshold limits, a suspicion is then evoked. The urgency of each suspicion period is classified into three levels of urgency (high, medium and low) depending on the probability of abnormality calculated from the Chernoff approximation, thereby aiding building managers in resource delegation matters. A FDD analysis for a time period of two months is conducted using the proposed method. The results show some high urgency classified suspicion periods within the investigated period, which are manually diagnosed by utilising room level sensor data. This led to the observation of a faulty occupancy counter. The proposed method shows promising outlook within the field of automated fault detection methods in terms of highlighting periods with abnormal behaviour.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Ventilation systems with desiccant wheel were analyzed from exergy destruction.•Main performances influencing factors for ventilation systems are put forward.•Improved ventilation systems with lower ...exergy destruction are suggested.•Performances of heat pumps driven ventilation systems are greatly increased.
This paper investigates the performances of ventilation systems with desiccant wheel cooling from the perspective of exergy destructions. Based on the inherent influencing factors for exergy destructions of heat and mass transfer and heat sources, provide guidelines for efficient system design. First, performances of a basic ventilation system are simulated, which is operated at high regeneration temperature and low coefficient of performance (COP). Then, exergy analysis of the basic ventilation system shows that exergy destructions mainly exist in the heat and mass transfer components and the heat source. The inherent influencing factors for the heat and mass transfer exergy destruction are heat and mass transfer capacities, which are related to over dehumidification of the desiccant wheel, and unmatched coefficients, which represent the uniformity of the temperature or humidity ratio differences fields for heat and mass transfer components. Based on these findings, two improved ventilation systems are suggested. For the first system, over dehumidification is avoided and unmatched coefficients for each component are reduced. With lower heat and mass transfer exergy destructions and lower regeneration temperature, COP and exergy efficiency of the first system are increased compared with the basic ventilation system. For the second system, a heat pump, which recovers heat from the process air to heat the regeneration air, is adopted to replace the electrical heater and cooling devices. The exergy destruction of the heat pump is considerably reduced as compared with heat source exergy destruction of the basic ventilation system and the first system, leading to a great enhancement of COP and exergy efficiency.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK, ZRSKP
•Real-time dynamic scenarios are investigated in the context of indoor environment.•The necessity of implementing CO2 mass balance Equation has been established.•A demand-controlled ventilation (DCV) ...resetting strategy is proposed.•The proposed approach demonstrates significant energy savings potential.
The ventilation component is one of the critical parts in an heating, ventilation and air-conditioning systems (HVAC) system and holds prime importance in ensuring operational efficacy and efficiency in terms of energy consumption and indoor environmental conditions. A true demand-based ventilation system with an economy air cycle not only offers reduced amounts of energy consumption but also can take part in a healthy indoor environment. This study provides true insight into the performance of a typical variable-air-volume air handling unit system under different operating conditions through a rigorous case study analysis in a real commercial building. To highlight pragmatic solutions to existing complexity within demand control ventilation strategies of the case building this study sets up real-time dynamic scenarios and investigates those scenarios in the context of indoor environment where both carbon dioxide (CO2) and volatile organic compound (VOC) concentrations are linked. To predict and monitor the indoor air CO2 concentration for the stated real time scenarios this study uses the mass balance equation for CO2 concentration. This study demonstrates that integrating the CO2 mass balance equation along with CO2 sensor data into the building management control system not only assists in reducing energy consumption but also takes part in a healthy indoor environment. This study suggests including the mass balance equation for CO2 concentration into the Australian ventilation standard AS 1668.2.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Sick building syndrome (SBS) is characterized by a group of common symptoms that occur inside the building like working offices, schools, malls or industries. It causes many adverse health effects ...due to tightly packed indoor environment. This is the first study done at the historical place of Karachi pertaining to SBS. A questionnaire based survey was conducted in Empress market, Karachi in October 2018 to find out the negative impact on human health as well as to give awareness about SBS to workers. This building consists of almost 280 shops and workers. The workers suffer from common health diseases like headache, fatigue and dryness of the throat. Congested areas, no ventilation, poor design and heavy traffic were observed. Fans were the only source of ventilation. SBS effects can be reduced by the good ventilation source, proper cleaning system, building maintenance and proper bimonthly checkup of the workers. Keywords: sick building syndrome, indoor environment, awareness, human health, ventilation systems
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The application of computational fluid dynamics (CFD) in the agricultural industry is becoming ever more important. Over the years, the versatility, accuracy and user-friendliness offered by CFD has ...led to its increased take-up by the agricultural engineering community. Now CFD is regularly employed to solve environmental problems of greenhouses and animal production facilities. However, due to a combination of increased computer efficacy and advanced numerical techniques, the realism of these simulations has only been enhanced in recent years. This study provides a state-of-the-art review of CFD, its current applications in the design of ventilation systems for agricultural production systems, and the outstanding challenging issues that confront CFD modellers. The current status of greenhouse CFD modelling was found to be at a higher standard than that of animal housing, owing to the incorporation of user-defined routines that simulate crop biological responses as a function of local environmental conditions. Nevertheless, the most recent animal housing simulations have addressed this issue and in turn have become more physically realistic.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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