Comparison of Mixed and Stratified Ventilation Systems in Production Areas: Experimental and Simulation Studies

2013 ◽  
Author(s):  
Mirko Schäfer ◽  
Johannes Wagner ◽  
Jens Hesselbach ◽  
Long Phan ◽  
Cheng-Xian Lin
Keyword(s):  
Energy Demand ◽  
Ventilation System ◽  
Experimental Studies ◽  
Carbon Dioxide Concentration ◽  
Simulation Models ◽  
Cooling Capacity ◽  
Climatic Regions ◽  
Industrial Buildings ◽  
Mass Loads ◽  
Ventilation Systems

Ventilation system can have significant influences on the energy consumption, especially in factories with high thermal loads. To remove generated thermal and mass loads from manufacturing areas, several mechanisms can be applied: mixing and layering ventilation. This paper shows experimental studies to compare mixed and stratified ventilation systems for industrial buildings. These experiments were conducted in a factory model with a scale of 1:2.5. The measurements consist of vertical distribution of carbon dioxide concentration and temperature in the ambient room. Additionally, a simulation study was conducted based on the same factory model to predict the annual energy demand of mixed and stratified ventilation systems in different climatic regions. The simulation models were validated with measurements from machines and devices in the authors’ laboratories and in the factories of project partners. The results show advantages in airflow, air quality, cooling capacity and energy demand at different climatic zones when using stratified ventilation.

Air Flow Straighteners’ Application to Reduce the Power Consumption of Exhaust Ventilation Schemes

2018 ◽  
Vol 875 ◽  
pp. 137-140 ◽  
Author(s):  
Valery N. Azarov ◽  
Natalia M. Sergina ◽  
I.V. Stefanenko
Keyword(s):  
Power Consumption ◽  
Air Flow ◽  
Ventilation System ◽  
Aerodynamic Resistance ◽  
Experimental Studies ◽  
Swirling Flows ◽  
Dust Collector ◽  
Exhaust Ventilation ◽  
Outlet Pipe ◽  
Ventilation Systems

It was proposed to use air flow screw straightened units in outlet pipe of the dust collectors to reduce the aerodynamic resistance of exhaust ventilation systems. It is allowed to decrease power consumption for their maintenance operation consequently. The article describes the results of experimental studies to evaluate its effectiveness by applying the tangential screw straightened unit within ventilation system. The obtained results showed that the use of this device allows reducing the aerodynamic resistance of the cyclone by 14.6%, and for counter-swirling flows’ dust collector (CSFC) by 17.2-23.6%. It was found that meanings of the aerodynamic resistance depend on value the share proportion of the flow entering into lower CSFC apparatus’ input.

The Trombe Wall as a Passive Air Conditioning System for Hot Climates

Proceedings ◽  
2019 ◽  
Vol 44 (1) ◽  
pp. 7
Author(s):  
Ivan Felis Enguix ◽  
Sina Ellesser ◽  
Constantino Torregrosa ◽  
María de Castro
Keyword(s):  
Energy Demand ◽  
Ventilation System ◽  
Mathematical Formulation ◽  
Experimental Studies ◽  
Air Conditioning System ◽  
Air Chamber ◽  
Air Ventilation ◽  
Trombe Wall ◽  
Service Sectors ◽  
Radiation Conditions

The residential and service sectors are responsible for a large portion of energy demand in modern societies. Therefore, today, buildings are expected to be energy-efficient and environmentally friendly. In this context, bioclimatic architecture and its related systems seem to show a good way to achieve this. A relevant system in this issue is the Trombe wall, under study in the present work. Although this system has been studied and implemented in cold climates (in heating mode), not so many theoretical and experimental studies have examined its operation in hot climates (in ventilation mode). To collaborate in this regard, an air-ventilation Trombe wall prototype was made and analysed, both theoretically and experimentally. The size of the prototype is 1 m height, 0.6 m width and 0.2 m length and it has an outer glass surface with a hole at the top, an air chamber, and an inner insulating panel with a hole at the bottom. These experiments were carried out both under controlled conditions in the laboratory and outside. In this sense, physical and psychrometric behaviour were obtained. As a conclusion, the system produced air currents between 0.2 and 0.4 m/s, improving the feeling of comfort by 3 °C. Thus, it demonstrates its possibility of use as a passive ventilation system. Additionally, both air temperature and speed data trends were fitted by mathematical formulation, which allows the prediction of the behaviour of the Trombe wall under different solar radiation conditions in hot climates.

scholarly journals A Comparative Study for Forced Ventilation Systems in Industrial Buildings to Improve the Workers’ Thermal Comfort

2021 ◽  
Vol 13 (18) ◽  
pp. 10267
Author(s):  
Mohamed I. Elhadary ◽  
Abdullah Mossa Y. Alzahrani ◽  
Reda M. H. Aly ◽  
Bahaa Elboshy
Keyword(s):  
Thermal Comfort ◽  
Cooling System ◽  
Volume Flow Rate ◽  
Ventilation System ◽  
Forced Ventilation ◽  
Industrial Buildings ◽  
Increase Productivity ◽  
Computational Fluid Dynamics Cfd ◽  
Spot Cooling ◽  
Ventilation Systems

The appropriate ventilation for factory spaces with regard to volume flow rate and air velocity inside the factory is one of the most important factors in the improvement of the thermal comfort of workers and in the reduction of the percentage of pollution they are exposed to, which in turn helps to improve the work environment and increase productivity. It also could improve the performance of machines. Hence, overheating can cause various problems and malfunctions. In this study, three types of mechanical ventilation systems are compared: the wall fan extract ventilation system, the roof fan extract ventilation system, and the spot cooling system. The Ansys software has been used to conduct the computational fluid dynamics (CFD) simulations for the different cases and the ventilation effectiveness factor (VEF) has been used to compare the performances of the three systems. The ventilation factor notably relies on the temperature distribution produced through the modeling and the results show that the most optimal system that can be used for similar factory spaces is the forced ventilation system. Finally, it is also the best in terms of energy consumption, despite the increase in the initial cost of its installation.

scholarly journals Determination of the most influential and cost-optimal building characteristics on the energy performance of commercial and industrial buildings

2019 ◽  
Vol 111 ◽  
pp. 03030
Author(s):  
Hilde Breesch ◽  
Barbara Wauman ◽  
Marcus Peeters
Keyword(s):  
Energy Demand ◽  
Ventilation System ◽  
Energy Performance ◽  
Building Envelope ◽  
Additional Energy ◽  
Heating And Cooling ◽  
Industrial Buildings ◽  
Thermal Bridges ◽  
Energy Simulations ◽  
The Cost

Unlike other types of buildings, commercial and industrial buildings have been so far “forgotten”. In addition, EPBD requirements are increasingly challenging for this type of buildings. This paper aims to identify the most building determinants of the energy performance of commercial and industrial buildings, focussing on the building envelope. Building energy simulations (BES) in TRNSYS are used to simulate the energy demand for heating and cooling in five building variants. The Pareto optimality approach that considers the economic and energetic objectives equally, is used to determine the cost-optimal solutions. The sensitivity analysis and cost-optimal study clearly reveal that airtightness seems to be the most important factor. Although heat recovery on a balanced mechanical ventilation system has a major impact on the energy demand for heating, this measure is not cost-optimal. The large impact of the U-value of the roof on the energy demand for heating is also reflected in the cost-optimal study. The insulation of the floor do not appear to be cost-optimal. Moreover, attention to construction detailing is important. The additional energy losses that can occur due to thermal bridges quickly reach significant values although solving the thermal bridges seems not to be cost-optimal.

Numerical Modeling and Experimental Studies of the Operational Parameters of the Earth-To-Air Heat Exchanger of the Geothermal Ventilation System

2021 ◽  
Vol 23 ◽  
pp. 42-64
Author(s):  
Boris Basok ◽  
Ihor Bozhko ◽  
Maryna Novitska ◽  
Aleksandr Nedbailo ◽  
Myroslav Tkachenko
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Ventilation System ◽  
Experimental Studies ◽  
Operating Conditions ◽  
Operational Parameters ◽  
Cross Sectional ◽  
Distinctive Features ◽  
Sectional Shape ◽  
Experimental Bench

This article is devoted to the analysis of the heat engineering characteristics of the operation of an Earth-to-Air Heat Exchanger, EAHE, with a circular cross-sectional shape, which is a component of the geothermal ventilation system. The authors analyzed literature sources devoted to the research of heat exchangers of the soil-air type of various designs and for working conditions in various soils. Much attention is paid to the issues of modeling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. The results of these studies are the basis for the development of a method for determining the optimal diameter of an EAHE under operating conditions for soil in Kyiv, Ukraine.

Development of an Evaporating Type Air Cooler for Ventilation Systems

2021 ◽  
pp. 37-44
Author(s):  
А. В. Бараков ◽  
В. Ю. Дубанин ◽  
Д. А. Прутских ◽  
А. А. Надеев
Keyword(s):  
Experimental Studies ◽  
Engineering Calculation ◽  
Design Calculation ◽  
Efficiency Coefficient ◽  
Empirical Relationships ◽  
Additional Energy ◽  
Air Cooler ◽  
Hot Season ◽  
Experimental And Theoretical Studies ◽  
Ventilation Systems

Постановка задачи. Подаваемый в помещения воздух в жаркое время года должен быть охлажден до комфортных температур. В связи с тем, что дополнительного расхода энергии на это охлаждение не предусмотрено, возможно применить воздухоохладитель испарительного типа. Однако известные в настоящее время результаты экспериментальных и теоретических исследований таких аппаратов не позволяют их проектировать, что препятствует их распространению. Рассмотрено строение такого аппарата и выполнены его теоретические и экспериментальные исследования, результаты которых могут быть использованы для инженерного расчета и конструирования подобных аппаратов. Результаты. Описан сконструированный авторами воздухоохладитель испарительного типа для систем вентиляции. Проведено теоретическое и экспериментальное исследование воздухоохладителя. Получены аналитические соотношения для определения времени движения насадки в «мокрой» камере аппарата, температуры охлажденного воздуха и температуры насадки в любом сечении контура циркуляции. Получены эмпирические соотношения для коэффициента эффективности охладителя и его гидравлического сопротивления. Выводы. Полученные зависимости послужат основой для разработки методики проектного расчета воздухоохладителей косвенно-испарительного типа с перемещающимся псевдоожиженным слоем в поле центробежных сил. Statement of the problem. The air supplied to the premises during the hot season must be cooled to comfortable temperatures. Due to the fact that additional energy consumption for this cooling is not provided, it is possible to use an evaporative-type air cooler. However, the currently known results of experimental and theoretical studies of such devices do not allow for their design, which prevents their spread. The structure of such an apparatus is considered and its theoretical and experimental studies are carried out, the results of which can be used for engineering calculation and design of such apparatus. Results. An evaporative-type air cooler designed by the authors for ventilation systems is described. A theoretical and experimental study of the air cooler has been carried out. Analytical relationships were obtained for determining the time of movement of the material checker in the «wet» chamber of the apparatus, the temperature of the cooled air and the temperature of the checker in any section of the circulation loop. Empirical relationships have been obtained for the efficiency coefficient of the cooler and its hydraulic resistance. Сonclusions. The obtained dependencies will serve as the basis for the development of a methodology for the design calculation of indirect-evaporative air coolers with a moving fluidized bed in the field of centrifugal forces.

scholarly journals Evaluation of litter material and ventilation systems in poultry production: III. litter reuse, darkling beetle populations and intestinal parasites

2011 ◽  
Vol 40 (6) ◽  
pp. 1372-1380
Author(s):  
Valéria Maria Nascimento Abreu ◽  
Doralice Pedroso de Paiva ◽  
Paulo Giovanni de Abreu ◽  
Arlei Coldebella
Keyword(s):  
Broiler Chickens ◽  
Intestinal Parasites ◽  
Organic Fertilizer ◽  
Ventilation System ◽  
Poultry Production ◽  
Rice Husks ◽  
Darkling Beetle ◽  
Eimeria Spp ◽  
Soybean Straw ◽  
Ventilation Systems

It was evaluated the quality of rice husks or soybean straw as litter substrate and the effect of litter reuse for four consecutive flocks of broiler chickens on populations of darkling beetle and intestinal parasite and as organic fertilizer. The experiment was carried out in four 12 m × 10 m poultry houses, internally divided in 4 boxes/poultry house with 200 birds/pen for four consecutive flocks, each flock with a duration of 42 days and with a 15-day downtime between flocks. The evaluated treatments were two ventilation systems (stationary or oscillating fans) and two litter materials (soybean straw or rice husks). Darkling beetle population was followed by collecting the insects in traps, three traps per box, and endoparasite litter contamination was determined by eggs/oocyst counts per gram of litter. Levels of dry matter, total nitrogen, total phosphorus, potassium, copper, zinc, manganese, iron, organic carbon and pH were evaluated by physical/chemical analyses of samples of the litters in each flock. Overall, litters of broilers used by three flocks meet the minimal legal requirements to be marketed as simple organic fertilizer, regardless to the material used as substrate. Soybean straw presented higher darkling beetle counts in stationary ventilation system as well as in oscillating ventilation system. The probability of rice husks litter present contamination by Eimeria spp oocysts is 18.78 times higher in rice husks than in soybean straw litter when both are submitted to oscillating ventilation, and 1.32 higher when stationary ventilation is used. Litter temperature does not influence significantly levels of contamination by oocysts.

scholarly journals Determination of conditions for spontaneous combustion of combustible dust deposits on equipment, in ventilation systems, and aspiration systems of buildings and structures

2020 ◽  
Vol 29 (4) ◽  
pp. 32-41
Author(s):  
L. P. Vogman ◽  
D. A. Korolchenko ◽  
A. V. Khryukin
Keyword(s):  
Spontaneous Combustion ◽  
Growth Dynamics ◽  
Operating Conditions ◽  
Industrial Enterprises ◽  
Process Characteristics ◽  
Industrial Buildings ◽  
Dust Deposits ◽  
Production Facilities ◽  
Ventilation Systems

Introduction. Determination of the scientifi cally substantiated frequency of cleaning the ducts of local exhausts of industrial buildings and structures is one of the tasks in the fi eld of fi re safety of industrial enterprises. The paper describes design methods, in particular, a method for determination of the induction period during spontaneous combustion of dust deposits in air ducts of ventilation systems and equipment, which can be used in solving problems focused on the development of preventive measures to ensure their fi re and explosion safety.Methods. In order to solve the problem set in this paper and compare the indicators obtained in the calculation and analytical part of the studies with the growth dynamics of deposits in real facilities, fi eld tests have been accomplished in the production facilities of the fl our mill of OJSC MK “Voronezhsky” and JSC Concern “Sozvezdiye”.Results and discussion. The timeframes for cleaning of deposits on ventilation (aspiration) equipment of buildings and structures cannot be universal for various industries and must take into account the dynamics of the growth of deposits depending on the specifi cs of combustible deposits, the workload of the production facilities of the protected object in a given period of time, and the operating conditions of the equipment. As a result of the experiments, it was found that the places of maximum accumulations of deposits are most often formed on the surfaces of joints and on the bends of pipelines of ventilation systems. The conditions of spontaneous combustion of combustible dust are studied by calculation and analytical method, depending on such process characteristics as the speed of the dust-air mixture fl ow in the duct, as well as the diameter of the duct’s cross section.Conclusions. The nomograms built on the basis of the studies performed can be used to determine the multiplicity of cleaning of combustible dusts of equipment and air ducts of industrial ventilation systems. The paper provides a calculation of the period of induction of spontaneous combustion of combustible dust deposits using the example of rye fl our with asymmetric heat transfer. Its signifi cance is due to the process of accumulation of deposits of combustible dust to a critical thickness in terms of spontaneous combustion conditions.

scholarly journals Energy-efficient outdoor air flow control in ventilation systems

2021 ◽  
Vol 5 (2) ◽  
pp. 18-24
Author(s):  
A. B. Sulin ◽  
◽  
A. A. Nikitin ◽  
T. V. Ryabova ◽  
S. S. Muraveinikov ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Block Diagram ◽  
Ventilation System ◽  
Flow Characteristics ◽  
Carbon Dioxide Concentration ◽  
Measured Parameter ◽  
Time Interval ◽  
Air Conditioning System ◽  
Control Zone ◽  
Exhaust Duct

A method for controlling the ventilation system flow characteristics is considered based on the forming principle an air temperature and carbon dioxide concentration predicted estimate in a room based on the changes dynamics analysis in these parameters in the supply and exhaust ducts. The expected microclimate parameters predicted assessment in real time opens up the possibility of using such elements and algorithms for controlling the ventilation and air conditioning system, which provide the required air quality with minimal energy consumption. The analysis calculates the finding probability the measured parameter inside or outside the control zone after a specified time interval. The algorithm for the control system actuators actuation for the channels of temperature and carbon dioxide concentration is presented in the block diagram form. The decision-making logic for actuating the actuators is based on the changes direction and intensity analysis in temperature and carbon dioxide concentration in the exhaust duct and the temperature difference between the supply and exhaust

scholarly journals Treeline advance - driving processes and adverse factors

2007 ◽  
Vol 1 ◽  
pp. 1-33 ◽  
Author(s):  
Friedrich Karl Holtmeier ◽  
Gabriele E. Broll
Keyword(s):  
Experimental Studies ◽  
Temporal Variations ◽  
Considerable Effect ◽  
Future Climate Change ◽  
Anthropogenic Factors ◽  
Site Conditions ◽  
Mature Trees ◽  
Climatic Regions ◽  
Functional Relationships ◽  
Animal Populations

The general trend of climatically-driven treeline advance is modified by regional, local and temporal variations. Treelines will not advance in a closed front parallel to the shift of any isotherm to higher elevations and more northern latitudes. The effects of varying topography on site conditions and the after-effects of historical disturbances by natural and anthropogenic factors may override the effects of slightly higher average temperatures. Moreover, the varying treeline-forming species respond in different ways to a changing climate. Forest advance upwards and northwards primarily depends on successful regeneration and survival of young growth rather than on increasing growth rates of mature trees. Every assessment of treeline response to future climate change must consider the effects of local site conditions and feedbacks of increasing tree population in modulating the climatically-driven change. Treeline-shift will influence regional and local climates, pedogenesis, plant communities, animal populations and biodiversity as well as having a considerable effect on economic changes in primary production. A better understanding of the functional relationships between the many treeline-relevant factors and treeline dynamics can be achieved only by extensive research at different scales within different climatic regions supported by as many as possible experimental studies in the field together with laboratory and remote sensing techniques.

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