scholarly journals Study of the effectiveness of the use of closed-type UV-recirculators for air disinfection in enclosed space

2021 ◽  
Vol 100 (11) ◽  
pp. 1229-1235
Author(s):  
Sergey V. Kostyuchenko ◽  
Alexander I. Vasil’ev ◽  
Andrey A. Tkachev ◽  
Anzhelika V. Zagainova ◽  
Irina V. Kurbatova ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Theoretical Calculation ◽  
Indoor Air ◽  
Culture Media ◽  
Total Bacterial Count ◽  
Agar Culture ◽  
Sabouraud Agar ◽  
Air Exchange Rate ◽  
Air Disinfection ◽  
Air Exchange

Introduction. The research is devoted to assessing the results of our studies of indoor air concerning microbial contamination during the operation of a UV recirculator with different modes (different UV doses). Also, a theoretical calculation of the influence of the ratio of the capacity of the UV recirculator to the air volume of the treated room on the efficiency of air disinfection has been made. Materials and methods. The study of indoor air in terms of total bacterial count (TBC), including coccal microflora and yeast and mould fungi, were carried out. Air sampling and evaluation were carried out under the requirements of Methodical guidelines MUK 4.2.2942-11 “Methods of sanitary and bacteriological studies of environmental objects, air and sterility control in medical institutions”. The evaluation of the results was carried out following R 3.5.1904-04, "The use of ultraviolet bactericidal radiation for disinfection of indoor air". During the study, agar culture media were used: Sabouraud agar, yolk-salt agar (YSA), meat-peptone agar (MPA), nutrient agar with the addition of 5% sheep blood (blood agar), bismuth sulfite agar, XLD-agar, cetrimide-agar, “Shine” agar, Endo agar. Results. As a result of the studies carried out, it was shown that a dose of UV irradiation of the order of 12-15 mJ/cm2 leads to an insignificant change in the concentration of bacteria (TBC) and fungi in the air (the efficiency was 58% and 69%, respectively). UV doses of the order of 25-30 mJ/cm2 significantly reduce the concentration of bacteria (TBC) and fungi in the air (efficiency was 99.99% and 99.4%, respectively). A theoretical calculation showed that it is practical to use a UV recirculator of such a capacity that provides an air exchange rate in the room of at least 4 (with ventilation operating at a rate of at least 2). Conclusion. To effectively use UV recirculators in enclosed spaces against bacteria and fungi, it is necessary to use models that provide a UV dose of at least 25-30 mJ/cm2. In contrast, their air capacity should provide an air exchange rate of at least 4.

scholarly journals First steps in the development of a possible measurement method to estimate the radon concentration as an indicator of the indoor air quality

2014 ◽  
Vol 29 (suppl.) ◽  
pp. 52-58
Author(s):  
Franz Roessler ◽  
Jai Azzam ◽  
Volker Grimm ◽  
Hans Hingmann ◽  
Tina Orovwighose ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Primary Energy ◽  
Air Pollutant ◽  
Daily Routine ◽  
Air Exchange Rate ◽  
Pollutant Concentrations ◽  
Air Exchange

The energy conservation regulation provides upper limits for the annual primary energy requirements for new buildings and old building renovation. The actions required could accompany a reduction of the air exchange rate and cause a degradation of the indoor air quality. In addition to climate and building specific aspects, the air exchange rate is essentially affected by the residents. Present methods for the estimation of the indoor air quality can only be effected under test conditions, whereby the influence of the residents cannot be considered and so an estimation under daily routine cannot be ensured. In the context of this contribution first steps of a method are presented, that allows an estimation of the progression of the air exchange rate under favourable conditions by using radon as an indicator. Therefore mathematical connections are established that could be affirmed practically in an experimental set-up. So this method could provide a tool that allows the estimation of the progression of the air exchange rate and in a later step the estimation of a correlating progression of air pollutant concentrations without limitations of using the dwelling.

scholarly journals An Unobstructive Sensing Method for Indoor Air Quality Optimization and Metabolic Assessment within Vehicles

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7202
Author(s):  
Yue Deng ◽  
Mark Sprowls ◽  
S. Jimena Mora ◽  
Doina Kulick ◽  
Nongjian Tao ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Air Quality ◽  
Metabolic Rate ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Accumulation Rate ◽  
Ventilation System ◽  
Reference Method ◽  
Air Exchange Rate ◽  
Air Exchange

This work investigates the use of an intelligent and unobstructive sensing technique for maintaining vehicle cabin’s indoor air quality while simultaneously assessing the driver metabolic rate. CO2 accumulation patterns are of great interest because CO2 can have negative cognitive effects at higher concentrations and also since CO2 accumulation rate can potentially be used to determine a person’s metabolic rate. The management of the vehicle’s ventilation system was controlled by periodically alternating the air recirculation mode within the cabin, which was actuated based on the CO2 levels inside the vehicle’s cabin. The CO2 accumulation periods were used to assess the driver’s metabolic rate, using a model that considered the vehicle’s air exchange rate. In the process of the method optimization, it was found that the vehicle’s air exchange rate (λ [h−1]) depends on the vehicle speeds, following the relationship: λ = 0.060 × (speed) − 0.88 when driving faster than 17 MPH. An accuracy level of 95% was found between the new method to assess the driver’s metabolic rate (1620 ± 140 kcal/day) and the reference method of indirect calorimetry (1550 ± 150 kcal/day) for a total of N = 16 metabolic assessments at various vehicle speeds. The new sensing method represents a novel approach for unobstructive assessment of driver metabolic rate while maintaining indoor air quality within the vehicle cabin.

DETERMINATION AND ANALYSIS OF AIR EXCHANGE RATE IN A LARGE GREENHOUSE EQUIPPED WITH INSECT PROOF NET

2007 ◽  
pp. 151-160
Author(s):  
H. Majdoubi ◽  
T. Boulard ◽  
A. Hanafi ◽  
H. Fatnassi ◽  
H. Demrati ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Air Exchange Rate ◽  
Air Exchange

Zonal air exchange rate of a passive solar house and resultant sensible air heat transfer

2018 ◽  
Vol 28 (7) ◽  
pp. 914-926 ◽  
Author(s):  
Ochuko Kelvin Overen ◽  
Edson Leroy Meyer ◽  
Golden Makaka ◽  
Sosten Ziuku ◽  
Sampson Mamphweli
Keyword(s):  
Heat Transfer ◽  
Exchange Rate ◽  
Air Exchange Rate ◽  
Passive Solar ◽  
Solar House ◽  
Air Exchange

scholarly journals The Effect of Ventilation Strategies on Indoor Air Quality and Energy Consumptions in Classrooms

Buildings ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 110 ◽  
Author(s):  
Luca Stabile ◽  
Angelamaria Massimo ◽  
Laura Canale ◽  
Aldo Russi ◽  
Alexandro Andrade ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Air Quality ◽  
Energy Saving ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
High Energy ◽  
Air Exchange Rate ◽  
Co2 Concentrations ◽  
Naturally Ventilated Buildings ◽  
Energy Consumptions

Most of the school buildings in Italy are high energy-demanding buildings with no ad-hoc ventilation systems (i.e., naturally-ventilated buildings). Therefore, reducing the heat losses of schools represent the main aspect to be dealt with. Nonetheless, the indoor air quality of the building should be simultaneously considered. Indeed, to date, energy consumptions and air quality are considered as incompatible aspects especially in naturally-ventilated buildings. The aim of the present paper is to evaluate the effect of different ventilation and airing strategies on both indoor air quality and energy consumptions in high energy-demanding naturally-ventilated classrooms. To this purpose, an Italian test-classroom, characterized in terms of air permeability and thermophysical parameters of the envelope, was investigated by means of experimental analyses and simulations through CO2 mass balance equation during the heating season. The air quality was assessed in terms of indoor CO2 concentrations whereas the energy consumptions were evaluated through the asset rating approach. Results clearly report that not adequate indoor CO2 concentrations are measured in the classroom for free-running ventilation scenarios even in low densely populated conditions (2.2 m2 person−1), whereas scheduled airing procedures can reduce the indoor CO2 levels at the cost of higher energy need for ventilation. In particular, when airing periods leading to the air exchange rate required by standards are adopted, the CO2 concentration can decrease to values lower than 1000 ppm, but the ventilation losses increase up to 36% of the overall energy need for space heating of the classroom. On the contrary, when the same air exchange rate is applied through mechanical ventilation systems equipped with heat recovery units, the ventilation energy loss contribution decreases to 5% and the overall energy saving results higher than 30%. Such energy-saving was found even higher for occupancy scenarios characterized by more densely populated conditions of the classroom typically occurring in Italian classrooms.

Nasal Mucosal Swelling in Relation to Low Air Exchange Rate in Schools

Indoor Air ◽  
1997 ◽  
Vol 7 (3) ◽  
pp. 198-205 ◽  
Author(s):  
Robert Walinder ◽  
Dan Norback ◽  
Gunilla Wieslander ◽  
Greta Smedje ◽  
Claes Erwall
Keyword(s):  
Exchange Rate ◽  
Air Exchange Rate ◽  
Nasal Mucosal Swelling ◽  
Air Exchange

Effective Energy Saving Research on the Air Exchange Rate of Residential Buildings in Guangzhou Based on the Software DeST-h

2011 ◽  
Vol 374-377 ◽  
pp. 430-435
Author(s):  
Wei Wei Du ◽  
Cui Cui Qin ◽  
Li Hua Zhao
Keyword(s):  
Exchange Rate ◽  
Exchange Rates ◽  
Energy Saving ◽  
Residential Buildings ◽  
Linear Regression Analysis ◽  
Functional Relation ◽  
Residential Building ◽  
Saving Rate ◽  
Air Exchange Rate ◽  
Air Exchange

Reasonable determination of indoor ventilation rates are the main content of residential ventilation designs, and can save consumption by air conditioners. Firstly, the energy saving potential of ventilation cooling technology in Guangzhou is analyzed in this paper. The cooling load of a residential building in Guangzhou with different air exchange rates is simulated by the DeST-h after indoor heating quantity of different rooms is set. The energy saving rate is analyzed, the functional relation between energy saving rate of ventilation and air exchange rate is obtained using the linear-regression analysis method. After a comprehensive consideration of various factors, including variation of energy efficiency, room volume, air outlet size, and that the maximum air exchange rates of different rooms are fixed.

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