Experimental study on the performance of hybrid ventilation system combining forced longitudinal flow and shaft natural ventilation in tunnels

2020 ◽  
Vol 103 ◽  
pp. 103491
Author(s):  
Dong Yang ◽  
Song Dong ◽  
Miao He ◽  
Zhongjie Zhang ◽  
Tao Du ◽  
...  
Keyword(s):  
Experimental Study ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Longitudinal Flow ◽  
Hybrid Ventilation

scholarly journals Comparison of indoor air pollutants concentration in two Romanian classrooms

2018 ◽  
Vol 32 ◽  
pp. 01023
Author(s):  
Vasilica Vasile ◽  
Alina Dima ◽  
Elena Zorila ◽  
Andrei Istrate ◽  
Tiberiu Catalina
Keyword(s):  
High School ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Pollutants ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Experimental Campaign ◽  
Air Pollutions ◽  
Hybrid Ventilation ◽  
Indoor Air Pollutants

This paper investigates the air pollutions in space ventilated in two High School classrooms. The analysis consists of comparison of one classroom with hybrid ventilation system and another one stander-by classroom with natural ventilation. Several studies regarding indoor air quality during the experimental campaign have been done for VOC, CO2, CO, other pollutants, keeping monitored for humidity and temperature. The experimental demonstrated that the highest value for CO2 in stander-by classroom is 2691 ppm and in classroom with hybrid ventilation is 1897 ppm, while values for CO are 1.1 / 1.1 ppm and VOC 0.14 / 0.06 ppm, better use hybrid ventilation.

scholarly journals Development of an Energy­Efficient Microclimate System for Dairy Herd Loose Keeping

2021 ◽  
Vol 15 (3) ◽  
pp. 73-80
Author(s):  
I. M. Dovlatov ◽  
S. S. Yurochka
Keyword(s):  
Heat Stress ◽  
Energy Consumption ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Live Weight ◽  
Animal Husbandry ◽  
Technical Literature ◽  
Limit Values ◽  
Hybrid Ventilation ◽  
Ventilation Systems

The authors studied the scientific and technical literature regarding the microclimate influence on dairy cattle productivity. It was found out that the building microclimate parameter deviation from certain limit values reduces milk yield by 10-20 percent decrease the live weight gain by 20-30 percent increases the mortality of young animals by 5-40 percent and reduces the number of lactations by 15-20 percent for the herd. (Research purpose) To conduct a survey of modern microclimate systems and their technical implementation for livestock buildings, suggesting the best option while reducing energy costs. (Materials and methods) A classification scheme was provided for microclimate systems. The factors affecting the microclimate of livestock premises were presented in one figure. The main functions of ventilation systems in animal husbandry were identified. The conditions for the use of natural and forced (tunnel) ventilation systems were described. The devices for changing the microclimate on the premises were presented. The possibility of using an overlapped ridge in the area of the roof ridge was considered to catch the airflow and minimize moisture penetration. (Results and discussion) To decrease energy consumption, it was proposed to shift from a supply ventilation system to a natural and hybrid ventilation system, which contains an air removal system, lighting equipment, heating elements, sensors, fans with spray nozzles, sashes. (Conclusions) It was found out that in summer, natural ventilation is unable to prevent heat stress from cows. It was determined that in case of heat stress within 60 days, losses could amount to 4.2 million rubles. To ensure optimal microclimate conditions and reduce costs from heat stress, it was proposed to use an innovative natural and hybrid ventilation system. The calculations showed that a 60-day energy consumption of  the proposed system equals 264 thousand rubles.

scholarly journals RESEARCH OF APARTMENT BUILDINGS‘VENTILATION SYSTEMS AND ANALYSIS OF SYSTEM RENEWAL OPTIONS / DAUGIABUČIŲ GYVENAMŲJŲ NAMŲ VĖDINIMO TYRIMAI IR SISTEMŲ ATNAUJINIMO GALIMYBIŲ ANALIZĖ

2015 ◽  
Vol 7 (4) ◽  
pp. 484-492 ◽  
Author(s):  
Kęstutis Valančius ◽  
Sabina Paulauskaitė ◽  
Violeta Motuzienė
Keyword(s):  
Experimental Study ◽  
Mechanical Ventilation ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Heating Season ◽  
Apartment Buildings ◽  
Air Ventilation ◽  
Hygienic Conditions ◽  
Ventilation Systems

The paper presents experimental study of apartment buildings' ventilation parameters which was carried out during the heating season. The results show that the existing apartment buildings often don‘t guarantee the hygienic conditions that are directly related to the indoor air ventilation. Also article contains an analysis of possibilities to upgrade the ventilation systems of apartment buildings. Four ventilation systems‘ upgrade options were examined. The economic analysis showed that according to the economic aspect the best solution for mechanical ventilation in the typical apartment houses is a centralized ventilation system which operates in combination with ground heat pump when supply ducts are mounted on the building facade, and extraction takes place at existing natural ventilation system channels. Straipsnyje pateikiami daugiabučių gyvenamųjų namų vėdinimo parametrų eksperimentiniai tyrimai, kurie buvo atlikti šildymo sezono metu. Tyrimų rezultatai rodo, kad esamuose daugiabučiuose namuose dažniausiai nėra užtikrinamos higieninės sąlygos, kurios yra tiesiogiai susijusios su šių namų vėdinimu. Taip pat straipsnyje pateikiama daugiabučio vėdinimo sistemų atnaujinimo galimybių analizė. Ekonomiškai išnagrinėti keturi vėdinimo sistemų atnaujinimo variantai. Atlikus ekonominę analizę, nustatyta, jog ekonominiu aspektu geriausias mechaninio vėdinimo sprendimas tipiniame daugiabučiame name yra centralizuota vėdinimo sistema, veikianti kombinuotai su gruntiniu šilumos siurbliu, kai tiekiamieji ortakiai montuojami ant pastato fasadų, o ištraukimas vyksta esamais natūralios vėdinimo sistemos kanalais.

scholarly journals Performance of a natural ventilation system with heat recovery in UK classrooms: An experimental study

2018 ◽  
Vol 179 ◽  
pp. 278-291 ◽  
Author(s):  
Paraskevi Vivian Dorizas ◽  
Stamp Samuel ◽  
Mumovic Dejan ◽  
Yan Keqin ◽  
Makris-Makridis Dimitris ◽  
...  
Keyword(s):  
Experimental Study ◽  
Heat Recovery ◽  
Natural Ventilation ◽  
Ventilation System

scholarly journals Three-Dimensional Simulation of Wind-Driven Ventilation Through a Windcatcher With Different Inlet Designs

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. Phuoc Huynh
Keyword(s):  
Wind Speed ◽  
Average Velocity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Ansys Fluent ◽  
Wind Velocities ◽  
Dimensional Simulation ◽  
Convergent Inlet

Abstract Windcatcher is an effective natural ventilation system, and its performance depends on several factors including wind speed and wind direction. It provides a comfortable and healthy indoor environment since the introduced fresh air decreases the moisture content and reduces the pollutant concentration. Since the wind speed and its direction are generally unpredictable, it is important to use special inlet forms and exits to increase the efficiency of a windcatcher. In this study, computational fluid dynamics (CFD) modeling is implemented using ansys fluent to investigate the airflow entering a three-dimensional room through a windcatcher with different inlet designs. Three designs are studied which are a uniform inlet, a divergent inlet, and a bulging-convergent inlet. The airflow pattern with all inlets provided adequate ventilation through the room. With all the applied wind velocities (1, 2, 3, and 6 m/s) at the domain's inlet, the divergent inlet shape has captured the highest airflow through the room and provided higher average velocity at 1.2 m high enhancing the thermal comfort where most of the human occupancy occurs. With 6 m/s wind velocity, the divergent inlet has captured 2.55% more flow rate compared to the uniform inlet and 4.70% compared to the bulging-convergent inlet, and it has also provided an average velocity at 1.2 m high in the room of 7.16% higher than the uniform inlet and 8.44% higher than the bulging-convergent inlet.

scholarly journals In vitro growth of Cattleya nobilior Rchb. f.: culture media, sealing systems and irradiance

2021 ◽  
Vol 51 ◽  
Author(s):  
Kaliana Gottschalk de Freitas ◽  
José Carlos Sorgato ◽  
Jackeline Schultz Soares ◽  
Luan Marlon Ribeiro
Keyword(s):  
Plant Height ◽  
Natural Ventilation ◽  
Culture Medium ◽  
Culture Media ◽  
Ventilation System ◽  
Light Condition ◽  
Leaf Length ◽  
In Vitro Growth ◽  
Randomized Design

ABSTRACT Some factors may influence the in vitro culture of native orchids, especially the culture medium, sealing system and light condition. This study aimed to evaluate the addition of banana pulp and peel in the formulation of culture media, sealing system and irradiance, in the in vitro growth of Cattleya nobilior Rchb. f. A completely randomized design was used in a factorial scheme with five culture media [Murashige & Skoog supplemented or not with banana pulp or peel (100 or 200g L-1)], two light conditions [3,000 K LED lamps (43 µmol m-2 s-1 or 86 µmol m-2 s-1)] and two sealing systems (natural and conventional ventilation), with six replicates of one vial each. The plant height, diameter of the largest pseudobulb, length of the largest root and of the largest leaf, fresh weight and number of leaves, roots and shoots were evaluated. The use of both the banana pulp and peel as additives in the culture medium formulation promoted the C. nobilior growth. The natural ventilation system increased the plant height, pseudobulb diameter and leaf length, while the conventional system promoted tillering.

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