Ventilation and energy performance of partitioned indoor spaces under mixing and displacement ventilation

Ahn, Hyeunguk; Rim, Donghyun; Lo, L. James

doi:10.1007/s12273-017-0410-z

Cited by 61 publications

(22 citation statements)

References 31 publications

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“…While the present study reveals the effect of sensor position on the DCV performance in typical private or shared offices, future studies can perform the analysis for the different types of densely occupied spaces such as classrooms and auditoriums [62][63] given that high CO2 concentrations and sensing errors can occur. In addition, the present study does not fully examine effects of asymmetric internal heat loads and interior partition walls on the non-uniform CO2 concentrations in occupied spaces [35,[64][65][66]. Future studies are warranted to investigate how such conditions can contribute to the nonuniform CO2 distributions and CO2 sensing performance.…”

Section: Effect Of Co2 Sensor Positionmentioning

confidence: 95%

“…Based on the previous studies and recommendations regarding CFD validation process [32][33][34][35][36], we performed experiments in a full-scale environmental chamber and used the measurement data for validating the CFD model as described in the following sections. Figure 1).…”

Section: Validation Of Cfd Modelmentioning

confidence: 99%

“…Note that considering it is more challenging to predict buoyancy-driven stratified airflow in displacement ventilation compared to the mixing airflow [30,33,35,42], the experimental validation study focused on the scenarios with displacement ventilation. Although experimental validation was not performed for mixing ventilation cases, the simulation results were validated using the analytical solutions of the heat and mass balance in the simulation domain.…”

Section: Validation Processmentioning

confidence: 99%

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Effect of sensor position on the performance of CO2-based demand controlled ventilation

Pei

Rim

Schiavon

et al. 2019

Energy and Buildings

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CO2-based demand controlled ventilation (DCV) can save energy while maintaining acceptable indoor air quality. CO2 concentration may vary within an occupied space and it is unclear how sensor location influences the ventilation and energy performances. The objective of the present study is to investigate the effect of CO2 sensor position on the performance of DCV systems under mixing and displacement ventilation. Experimentally validated computational fluid dynamics (CFD) models were simulated under representative indoor ventilation and occupancy conditions. The results show that the ventilation strategy, occupancy level, and air change rate have notable impacts on the CO2 sensing performance. Under mixing ventilation, CO2 sensors placed at the room exhaust can meet the requirements of sensor accuracy defined by ASTM E741 and California Title 24. However, the sensor errors associated with sensor location can be higher than the acceptable threshold under displacement ventilation, which exhibits vertical CO2 stratification with two separated zones (lower transition zone and upper uniform zone). The dividing height of the two zones is highly sensitive to the occupancy level. In such cases, exhaust sensors can overestimate the breathing zone concentration and result in additional energy consumptions for thermal conditioning as well as fan operation, especially for densely occupied buildings. The study findings suggest that for ensuring good performance of CO2-based displacement ventilation, it is necessary to develop quantitative relationships between CO2 concentrations at the breathing height and the room exhaust considering ventilation strategies. Keywords: indoor air quality; CO2 sensing; computational fluid dynamics; building energy; displacement ventilation Highlights • CO2 sensors near occupants result in large errors under displacement ventilation • CO2 sensors at breathing height perform well for constant occupancy conditions • CO2 sensors at breathing height yield errors with varying occupancy • Under mixing ventilation, CO2 sensors at the room exhaust yield a good accuracy Energy and Buildings, Aug. 2019 ! https://doi.

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Section: Effect Of Co2 Sensor Positionmentioning

confidence: 95%

Section: Validation Of Cfd Modelmentioning

confidence: 99%

Section: Validation Processmentioning

confidence: 99%

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Effect of sensor position on the performance of CO2-based demand controlled ventilation

Pei

Rim

Schiavon

et al. 2019

Energy and Buildings

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“…41,42 Besides air exchange rates, two different diffuser positions, upper and lower air supply inlets of the room, were considered to investigate the impact of ventilation strategy (ie, mixing and displacement ventilation). 43,44 Finally, the effect of air mixing intensity around the human surface was examined This resulted in an average room concentration of 4 ppb without any chemical reactions for the normal breathing condition. 27,46 3 | RE SULTS Depending on the emission location of oxidation products, the spatial distributions are different.…”

Section: Parametric Analysismentioning

confidence: 99%

Spatial distributions of ozonolysis products from human surfaces in ventilated rooms

et al. 2020

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Ozone indoors is a hazardous gas for humans, due to its high reactivity. 1,2 Previous studies have shown that even low concentrations of ozone can have adverse health effects on children, exacerbating asthma, breath shortness, and chronic bronchitis. 3,4 As a strong oxidant, ozone reacts with indoor organic compounds, especially with unsaturated organic compounds. Human skin oil contains unsaturated compounds and plays a significant role as an ozone sink. 5-8 Ozone reaction with skin oil produces primary and secondary products such as carbonyls and di-carbonyls. 6,9,10 Some carbonyl products are known to be skin and respiratory irritants, 11-13 so it is important to examine factors that influence personal exposure to both ozone and ozonolysis products to estimate the impact of these species on occupants.

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“…Необходимо отметить, что располагаемое давление в квартирах верхних этажей может достигнуть отрицательных значений, что приведет к блокировке работы системы вентиляции жилого дома. Поэтому, необходимо применение специальных приточных устройств для регулируемого притока наружного воздуха в помещения квартир [1,10,11,12]. Дополнительный приток воздуха предусматривается за счет применения технических устройств, не требующих для своей работы затрат электрической энергии.…”

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Research Efficiency of Natural Ventilation System of Apartment Building

Abdrazakov¹,

Povarov²

2019

Bulletin of Belgorod State Technological University Named After. V. G. Shukhov

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The analysis of existing research in the field of ventilation systems is performed and the current shortcomings of the ventilation systems of secondary apartment houses of series 114–85 are identified. The instability of the natural ventilation system of an apartment building characterized by variable air exchange and overturning ventilation in the ventilation ducts is demonstrated. Field studies of the natural ventilation system efficiency of an apartment house series 114–85 located in Saratov are carried out. According to the research results, the absence of traction and the presence of reverse traction in the exhaust ducts of the ventilation system are revealed. The initial reason for the lack of normal traction in the ventilation system associated with its calculation in the project of building a house series 114-85 for open mode operation is stablished. The increased tightness of windows and doors of apartments is determined, resulting in a reversed traction and the impossibility of uniform distribution of air vertically of the house, therefore installing only the exhaust system of the natural ventilation of an apartment building is inefficient. It is established that the ventilation channel in the kitchen is constantly working to extract air from the premises of the apartments, since the bathroom door is tightly closed that does not correspond to the normative indicators. The analysis of ventilation system on the example of three-bedroom apartments shows the need for additional supply devices for controlled flow of outside air into the premises of apartments. The use of supply wall valves of KIV-125 brand and window ventilation valves of Air Box Comfort brand is provided. A methodology of selection the modern, highly efficient energy saving models of turbo ventilators is presented, increasing traction in exhaust ventilation ducts at 40 % and independent of direction and wind gusts.

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Ventilation and energy performance of partitioned indoor spaces under mixing and displacement ventilation

Cited by 61 publications

References 31 publications

Effect of sensor position on the performance of CO2-based demand controlled ventilation

Effect of sensor position on the performance of CO2-based demand controlled ventilation

Spatial distributions of ozonolysis products from human surfaces in ventilated rooms

Research Efficiency of Natural Ventilation System of Apartment Building

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